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54,992,251 | https://en.wikipedia.org/wiki/Botrytis%E2%80%93induced%20kinase%201 | Botrytis–induced kinase 1 (BIK1) is a membrane-anchored enzyme in plants. It is a kinase that provides resistance to necrotrophic and biotrophic pathogens. As its name suggests, BIK1 is only active after being induced by Botrytis infection. When Botrytis cinerea is present, the BIK1 gene is transcribed so that the kinase is present to defend the cell. BIK1 functions to regulate the amount of salicylic acid (SA) present in the cell. When Botrytis cinerea or Alternaria brassicicola or any other necrotrophic pathogen is present, BIK1 is transcribed to regulate the pathogen response mechanisms. When BIK1 is present, SA levels decrease, allowing the nectrotrophic response to take place. When nectrotrophic pathogens are not present, BIK1 is not transcribed and SA levels increase, limiting the necrotrophic resistance pathway. Only the pathogenic defense response that is initiated by BIK1 is dependent on SA levels. Non-pathogenic cellular functions occur independently. In terms of non-pathogenic cellular functions, BIK1 is described as a critical component of ET signaling and PAMP-triggered immunity to pathogens.
Functions of BIK1
For cellular processes that are not directly related to pathogen resistance or defense, BIK1 does not utilize traditional defense-mediating hormones such as SA, JA, or ACC, but instead utilizes an herbicide, known as paraquat which produces ROIs. It is believed that SA, JA, and ACC have no effect on BIK1 induction because they are likely located downstream from the BIK1 gene, or it is possible that BIK1 operates completely independently. However, it is believed that BIK1 does play a vital role in the ET signaling pathway. Based on the signaling function of BIK1 in ET responses, it is believed that Botrytis-induced kinase1 accumulates response signals that it receives from upstream regulators and then integrates them into its own resistance mechanism.
BIK1 is a receptor-like cytoplasmic kinase (RLCK) that associates with a cell-surface receptor, FLS2, and a co-receptor kinase, BAK1 to transduce signals when a PAMP is detected. In order for BIK1 to be activated, site-specific phosphorylation must occur.
Effects of Phosphorylation on BIK1 Function
Because BIK1 is a possible regulator of the FLS2-BAK1 complex, it is speculated that in vitro, BAK1 phosphorylates BIK1, which then phosphorylates both FLS2 and BAK1. However, in vivo, BIK1 is not phosphorylated until about 5-10 minutes after the addition of FS2, and the peak phosphorylation occurs just after the phosphorylation of the FS2-BAK1 complex. It is speculated that BIK1 activation might be enhanced through transphosphorylation by BAK1 rather than by FLS2 because FLS2 more likely serves as a scaffold protein for the arrangement of the BAK1-FLS2 complex. This hypothesis will require more testing in vivo. Research has shown that BIK1 and BAK1 are signaling partners for the flagellin receptor FLS2 and that the three together initiate defense response. However, BIK1 and BAK1 phosphorylate different residues of the FLS2 receptor with the exception of only a select few. This suggests that both BAK1 and BIK1 play unique roles in defense response by a series of phosphorylation reactions with one another and the flagellin receptor FLS2.
BIK1 effect on Plant Growth and Development
Root systems in plants with an expressed BIK1 gene and in plants with a loss-of-function mutant show that without an expressed BIK1 gene, roots grow more laterally, in greater numbers, and with shorter primary roots. With a functional BIK1 gene, roots grew downward into the soil and had less root hairs. Additionally, without a functional BIK1 gene, leaves showed serrated edges and considerable wrinkles whereas leaves with a functional BIK1 gene showed stronger, smoother leaves. Flowering plants that lack a functional BIK1 gene flower an average of six days before those with a functional BIK1 gene and show weaker stem strengths, reduced fertility, and smaller siliques. The BIK1 protein contributes to overall stronger stems, broader leaves, and a healthy flowering timeline. Plants lacking a BIK1 protein or that have a BIK1 protein whose functions are being inhibited may exhibit a shorter flowering period and a smaller stature for the plant overall. This suggests that BIK1 plays a significant role in a plant's ability to grow properly as well as its ability to maintain an adequate rigidity and stem strength that contribute to overall plant health.
Research
Current research regarding Botrytis-induced kinase1 aims to determine how BIK1 interacts with MAPK pathway proteins as well as with the OXI1 kinase. Also, studies are being conducted to determine the relationship between BIK1 and the phosphorylizing homolog kinases PEPR1 and PEPR2. Though it is believed that PEPR1 and PEPR2 act as enzymes toward BIK1 and phosphorylate the kinase, research is still being done to examine the effects of the interaction on a broader scale. Previously published research suggests that PEPR1 and PEPR2 work with the ET signal pathway and Botrytis-induced kinase1 in order to amplify the defense mechanism in immune response. Additionally, future research may explore the mechanism that allows BIK1 and BAK1 to cooperate with the FLS2 receptor to initiate defense response. While it is known that the three work together and each is required for the process to occur efficiently, but the exact relationship between the three remains unknown and the specific binding residues for each component have yet to be determined in vivo.
References
EC 2.7
Immune system
Protein kinases
Signal transduction | Botrytis–induced kinase 1 | [
"Chemistry",
"Biology"
] | 1,280 | [
"Immune system",
"Signal transduction",
"Organ systems",
"Biochemistry",
"Neurochemistry"
] |
54,992,733 | https://en.wikipedia.org/wiki/PGC%201 | PGC 1 is a radio galaxy located about 1.1 billion light-years away in the constellation Pisces.
Physical characteristics
PGC 1 appears to have a companion galaxy called SDSS J235958.29+004208.6. However, the difference in the recessional velocities for the two galaxies corresponds to about 55 million light years difference in distance, so it is possible that they may not be a physical pair, but however they are essentially the same distance.
Radio Jet
PGC 1 has a radio jet coming out of its center.
See also
Principal Galaxies Catalogue
References
External links
Galaxies
Pisces (constellation)
000001
Radio galaxies | PGC 1 | [
"Astronomy"
] | 138 | [
"Pisces (constellation)",
"Galaxy stubs",
"Astronomy stubs",
"Constellations"
] |
54,993,244 | https://en.wikipedia.org/wiki/Environmental%20personhood | Environmental personhood or juridic personhood is a legal concept which designates certain environmental entities the status of a legal person. This assigns to these entities, the rights, protections, privileges, responsibilities and legal liability of a legal personality. Because environmental entities such as rivers and plants can not represent themselves in court, a "guardian" can act on the entity's behalf to protect it. Environmental personhood emerged from the evolution of legal focus in pursuit of the protection of nature. Over time, focus has evolved from human interests in exploiting nature, to protecting nature for future human generations, to conceptions that allow for nature to be protected as intrinsically valuable. This concept can be used as a vehicle for recognising Indigenous peoples' relationships to natural entities, such as rivers. Environmental personhood, which assigns nature (or aspects of it) certain rights, concurrently provides a means to individuals or groups such as Indigenous peoples to fulfill their human rights.
Background
The United States Professor Christopher D. Stone first discussed the idea of attributing legal personality to natural objects in the 1970s, in his article "Should trees have standing? Towards legal rights for natural objects". A legal person cannot be owned; therefore, no ownership can be attributed to an environmental entity with established legal personality. Standing is directly related to legal personality. Entities with standing, or locus standi, have the right or capacity to bring action or appear in court. Environmental entities cannot themselves bring action or appear in court. However, this action or standing can be achieved on behalf of the entity by a representing legal guardian. Representation could increase protection of culturally significant aspects of the natural environment, or areas vulnerable to exploitation and pollution.
Although there is no federal law in the United States implementing environmental personhood, the idea has been advocated for by a US Supreme Court Justice. In the decision of the 1972 US Supreme Court case Sierra Club v. Morton, Justice William Douglas wrote a dissenting opinion arguing that certain "environmental elements" should have locus standi, and that people with a meaningful relationship to that environmental element should be able to act on its behalf for its protection. As of June 2021, at least 53 initiatives in 12 countries have used the concept of 'person' in their legal text.
The Sierra Club, an environmental advocacy group, brought this suit against then Secretary of the Interior of the United States, Roger C. B. Morton stating that the federal government, according to the Administrative Procedure Act, could not grant permits for developers to build infrastructure – specifically a highway, powerlines, and a ski resort – in the Mineral King Valley, part of the Sequoia National Forest. The Sierra Club aimed to protect this undeveloped land within the national forest, but the U.S. Court of Appeals for the Ninth Circuit had stated that because the members of the Sierra Club would not be directly affected they could not sue under the Administrative Procedure Act, which "provides standards for judicial review" for instances where a person is negatively impacted by an agency action, such as granting a permit. The Supreme Court agreed that the Sierra Club could not sue under the Administrative Procedure Act, as it could not show that the actions of the defendant caused or would cause injury to its members. This ruling led Supreme Court Justice William Douglas to write his dissenting opinion, arguing that people should be allowed to sue on behalf of non-living things writing, "[t]hose who have that intimate relation with the inanimate object about to be injured, polluted, or otherwise despoiled are its legitimate spokesmen." This opinion is shared by those who continue to argue for environmental personhood in the United States and around the world.
Domestic rights of nature
New Zealand
In 2014, Te Urewera National Park was declared Te Urewera, an environmental legal entity. The area encompassed by Te Urewera ceased to be a government-owned national park and was transformed into freehold, inalienable land owned by itself.
Following the same trend, New Zealand's Whanganui River was declared to be a legal person in 2017. This new legal entity was named Te Awa Tupua and is now recognised as "an indivisible and living whole from the mountains to the sea, incorporating the Whanganui River and all of its physical and metaphysical elements." The river would be represented by two guardians, one from the Whanganui iwi and the other from the Crown.
Also in 2017, the New Zealand government signed an agreement granting similar legal personality to Mount Taranaki and pledging a name change for Egmont National Park, which surrounds the mountain.
India
The Ganges and Yamuna Rivers are now considered legal persons in an effort to combat pollution. The rivers are sacred to Hindu culture for their healing powers and attraction of pilgrims who bathe and scatter the ashes of their dead. The rivers have been heavily polluted by 1.5 billion litres of untreated sewage and 500 million litres of industrial waste entering the rivers daily.
The High Court in the northern Indian state of Uttarakhand ordered in March 2017 that the Ganges and its main tributary, the Yamuna, be assigned the status of legal entities. The rivers would gain "all corresponding rights, duties and liabilities of a living person." This decision meant that polluting or damaging the rivers is equivalent to harming a person. The court cited the example of the New Zealand Whanganui River, which was also declared to possess full rights of a legal person.
This development of environmental personhood has been met with scepticism as merely announcing that the Ganges and Yamuna are living entities will not save them from significant, ongoing pollution. There is a possible need to change long-held cultural attitudes towards the Ganges, which hold that the river has self-purifying properties.
There is further criticism that the guardianship of the rivers was only granted to Uttarakhand, a region in northern India which houses a small part of the rivers' full extent. The Ganges flows for 2,525 km through Uttarakhand, Uttar Pradesh, Bihar, Jharkhand and West Bengal, with only a 96 km stretch running through Uttarakhand. Only a small section of the 1,376 km Yamuna tributary runs through Uttarakhand – which also crosses through the states of Haryana, Himachal Pradesh, Delhi and Uttar Pradesh.
Regardless of scepticism surrounding the decision of the Uttarakhand High Court, proclaiming these vulnerable rivers as legal entities invokes a movement of change towards environmental and cultural rights protection. The decisions may be built upon as a foundation for future environmental legislative change.
United States
In 2006, the borough of Tamaqua, Pennsylvania, worked with a rights of nature group called the Community Environmental Legal Defense Fund (CELDF). Together, the groups drafted legislation to protect the community and its environment from the dumping of toxic sewage. Since 2006, CELDF has assisted with over 30 communities in ten states across the United States to develop local laws codifying the rights of nature. CELDF also assisted in the drafting of Ecuador's 2008 constitution following a national referendum.
Besides Tamaqua, several other towns throughout the United States have drafted legislation that would, in effect, give nature natural rights. In 2008, residents in a town by the name of Shapleigh, Maine, added new provisions to the town's legal code. The new sections granted rights to the nature and natural bodies of water that surrounded Shapleigh, and purported to strip the rights of corporations granted by the United States Constitution. What prompted the change to Shapleigh's legal code was a plan by the Nestle Corporation, which owns several water bottle brands such as Poland Spring, to pump truckloads of groundwater from Shapleigh to a water bottling facility. As of 2019, no lawsuits have been filed against Shapleigh, Maine for the change in the town's legal code, and the Nestle Corporation has not chosen to challenge the code either. In this case the CELDF did not assist the residents of Shapleigh in drafting sections 99-11 and 99-12 of their legal code, they were instead assisted by lawyers from Vermont.
In April 2013, the CELDF assisted officials in Mora County, New Mexico, in creating an ordinance that limited the ability of corporations to extract gas and oil, and gave rights to the natural ecosystems and bodies of water that resided within Mora County. This ordinance made Mora County the very first place within the United States to ban the production of gas and oil, within a certain area, in an official statement. A lawsuit was filed against Mora County on November 12, 2013, which asserted that Mora County's ordinance infringed on corporations rights, especially the first, fifth, and fourteenth amendments. In January 2015, Mora County's ordinance was overthrown by U.S. District Judge James O. Browning as he viewed the ordinance to violate the first amendment rights of corporations.
In early 2014, Grant Township, Indiana, Pennsylvania, enlisted the CELDF's help in drafting an ordinance that would give the natural bodies of water surrounding Grant Township natural rights. A company named Pennsylvania General Energy (PGE) had converted an old oil and gas well into a "wastewater injection well," and residents became concerned for what that could mean for the natural ecosystems surrounding their township. The water in a wastewater injection well is waste that is left over from a process called fracking. This water can contain harmful pollutants and chemicals that can poison groundwater. In Grant Township, most residents rely on the Little Mahoning Creek for their water needs. If the wastewater injection well were to leak, there is a possibility it could contaminate the Little Mahoning. The risk of contamination is what prompted Grant Township residents to ask the CELDF for assistance in drafting an ordinance. Grant Township's ordinance gave natural rights to the ecosystems and bodies of water that were within the borders of Grant Township. Grant Township's ordinance also stripped corporations of their rights deeming that corporations would not be seen as "persons" within the borders of Grant Township. In August 2014, PGE sued Grant Township which began a legal battle that would last for almost five years. Grant Township lost the lawsuit against PGE in April 2019, and Judge Susan Baxter ordered Grant Township to pay PGE's legal expenses which were over $100,000. In addition, Grant Township's ordinance was declared invalid.
On 26 February 2019, voters in Toledo, Ohio passed the Lake Erie Bill of Rights. The main point of the Lake Erie Bill of Rights is that Lake Erie has the right to "flourish." Residents of Toledo, and surrounding areas, have suffered times where the tap water, which comes from Lake Erie, was not safe to drink, or use, due to pollution. Cases of unsafe water conditions, amongst other pollution problems, is what prompted residents of Toledo to ask the CELDF for help. On 27 February 2019, the day after the Lake Erie Bill of Rights was passed by voters, a lawsuit was filed by an Ohio farmer. On 27 February 2020, U.S. District Judge Jack Zouhary invalidated the bill, ruling it was "unconstitutionally vague" and beyond "the power of municipal government in Ohio."
In the summer of 2019, the Yurok tribe in northern California gave the Klamath River personhood status.
Ecuador
The rights of nature "to exist, persist, maintain and regenerate its vital cycles" have been proclaimed under Ecuador's 2008 constitution. This occurred after a national referendum in 2008, allowing the Ecuador constitution to reflect rights for nature, a world first. Every person and community has the right to advocate on nature's behalf. The Constitution proclaims that the "State shall give incentives to natural persons and legal entities and to communities to protect nature and to promote respect for all the elements comprising an ecosystem."
The first successful case of the rights of nature implementation under Ecuador constitutional law was presented before the Provincial Court of Justice of Loja in 2011. This case involved the Vilcabamba River as the plaintiff, representing itself with its own rights to 'exist' and 'maintain itself' – as it attempted to halt construction of a government highway project interfering with the natural health of the river. This case was brought before court by two individuals, Richard Frederick Wheeler and Eleanor Geer Huddle, as legal guardians acting in favour of nature – specifically the Vilcabamba River. A constitutional injunction was granted in favour of the Vilcabamba River and against the Provincial government of Loja, attempting to conduct the environmentally-harmful project. The project was forced to be halted and the area was to be rehabilitated.
Bolivia
The constitutional change in Ecuador was followed legislatively by Bolivia in 2010, passing the 'Law of the Rights of Mother Earth' (Ley de Derechos de la Madre Tierra). This legislation designates Mother Earth the character of 'a collective subject of public interest' with inherent rights specified in the law. The Law of the Rights of Mother Earth give aspects of legal personhood to the natural environment. Judicial action can be taken for infringements against individuals and groups as part of Mother Earth as 'a collective subject of public interest'. The legislation states that "Mother Earth is the dynamic living system made up of the indivisible community of all living systems, living, interrelated, interdependent and complementary, sharing a common destiny."
Colombia
The Colombia Constitutional Court found in November 2016 that the Atrato River basin possesses rights to "protection, conservation, maintenance, and restoration." This ruling came about as a result of degradation to the river basin from mining, impacting nature and harming of Indigenous peoples and their culture. The court referred to the New Zealand declaration of the Whanganui River as a legal person holding environmental personhood. The court ordered that joint guardianship would be undertaken in the representation of the Atrato River basin. Similarly to the New Zealand declaration, the representatives would come from the national government and the Indigenous people living in the basin.
The court stated:(I)t is the human populations that are interdependent of the natural world – and not the opposite – and that they must assume the consequences of their actions and omissions with the nature. It is a question of understanding this new sociopolitical reality with the aim of achieving a respectful transformation with the natural world and its environment, as has happened before with civil and political rights…Now is the time to begin taking the first steps to effectively protect the planet and its resources before it is too late...In April 2018 the Supreme Court of Colombia has issued a decision recognizing the Amazon River ecosystem as a subject of rights and beneficiary of protection.
Canada
The Magpie river in the Côte-Nord region of Quebec was given a set of rights, including the right to take legal action, by the Innu Council of Ekanitshit and Minganie county. Representatives can be appointed by the regional municipality and the Innu to act on behalf of the river and take legal action to protect its rights which they define as: "the right to flow; the right to respect for its cycles; the right for its natural evolution to be protected and preserved; the right to maintain its natural biodiversity; the right to fulfil its essential functions within its ecosystem; the right to maintain its integrity; the right to be safe from pollution; the right to regenerate and be restored; and finally, the right to sue." This aligns with the belief that the river is an independent, living entity separate from human activity.
Spain
In Spain, the Law recognizes environmental personhood to Mar Menor.
Arguments for and against
The concept of environmental personhood is controversial, even among environmentalists. One can advocate for a legal framework that acknowledges rights of nature, but may not believe that environmental personhood is the right way to implement it. Proponents of environmental personhood argue that it is valuable to be able to sue on behalf of the environment, because it would allow for environmental protection that does not rely on harm being done to human beings. Environmental personhood also better honors the significant relationships of Indigenous peoples to their environment.
However, there are arguments against the concept of environmental personhood. One concern is that the status of legal personhood implies a right not only to sue but to be sued. Can a river be liable for damage it causes in a flood? Would the guardians of that river be asked to pay for damages caused by natural disasters? Community Environmental Defense Fund lawyer Lindsey Schromen-Wawrin writes that this concern is "one of the things that could derail in my opinion the ability for rights in nature to be a check on destructive activities and instead could set up kind of like natural resource trustees for ecosystems where there's a flood and now the ecosystem has to pay out of the fund that would otherwise have gone to restoring habitat that had been destroyed."
Another concern is that even with a legal right to sue on behalf of a natural entity, lawsuits are expensive. There are issues of environmental justice if the cost to exercise the right to sue is inaccessible. Other issues arise when environmental entities exist beyond the bounds of the jurisdiction that decided on environmental personhood, which was the case with a river which held rights as a legal person in Uttarakhand, India. According to reporting by National Public Radio, there are also cases where the rights of environmental entities may be at odds with the rights of human beings, "Many of the [environmental personhood] laws have also been met with resistance from industry, farmers and river communities, who argue that giving nature personhood infringes on their rights and livelihoods."
Significance for cultural human rights
The recognition of the Whanganui River as a legal entity in New Zealand (Te Awa Tupua) encompassed a vivid sense of cultural "inalienable connection" to the local iwi and hapu of the river. Māori culture considers natural features such as the Whanganui River as ancestors and iwi hold deep connections with them as living entities. This inalienable connection of indigenous culture to their natural surroundings is apparent in other parts of the world such as Colombia where a similar environmental personhood declaration was made for the Atrato River basin.
The lead negotiator for the Whanganui iwi, Gerrard Albert, said "we consider the river an ancestor and always have...treating the river as a living entity is the correct way to approach it, as an indivisible whole, instead of the traditional model for the last 100 years of treating it from a perspective of ownership and management." James D K Morris and Jacinta Ruru suggest that giving "legal personality to rivers is one way in which the law could develop to provide a lasting commitment to reconciling with Maori." This was the longest-running legal dispute in New Zealand. The Whanganui iwi had been fighting to assert their rights in harmony with the river since the 1870s.
Ecocide
The concept of environmental protection on behalf of the environment is not new, and widespread harm to the environment has a name: ecocide. The Independent Expert Panel for the Legal Definition of Ecocide defines ecocide as "unlawful or wanton acts committed with knowledge that there is a substantial likelihood of severe and either widespread or long-term damage to the environment being caused by those acts." There are advocates of making ecocide an international crime, like the crimes dealt with by the Rome Statute of the International Criminal Court (ICC). This would place ecocide alongside currently recognized international crimes like genocide, war crimes, and crimes against humanity. If added, ecocide would be the only crime "in which human harm is not a prerequisite for prosecution." This protection of nature for nature's sake is central to the advocacy behind environmental personhood. Do human beings need to be harmed to warrant legal action? The concept of ecocide is not new, nor is the advocacy for adding it to the Rome Statute of the ICC.
Extraterrestrial
With new increased interest in extraterrestrial spaceflight in the 2020s planetary personhood has been discussed, for Mars (including Martian meteorites), but particularly for the Moon, recognizing the Moon as having memory and agency, with its surface interacting, changing and remembering.
See also
Corporate personhood
Legal person
Personhood
Rights of nature
Te Urewera
Whanganui River
References
External links
Whanganui River Maori Trust Board
Whanganui's Official Tourism Portal
Te Urewera the Tuhoe Homeland
CELDF Website
2008 Constitution of Ecuador
Legal entities
Rights
Environmental law legal terminology
Corporate personhood
Personhood
Environmental law
Environmental ethics | Environmental personhood | [
"Environmental_science"
] | 4,240 | [
"Environmental personhood",
"Environmental ethics"
] |
54,993,625 | https://en.wikipedia.org/wiki/Phosphirene | Phosphirene is the hypothetical organophosphorus compound with the formula C2H2PH. As the simplest cyclic, unsaturated organophosphorus compound, phosphirene is the prototype of a family of related compounds that have attracted attention from researchers.
Phosphirenes, that is substituted phosphirene compounds where one or more of the H's are replaced by organic substituents, are far more commonly discussed than the parent phosphirene. The first example of a phosphirene, 1,2,3-triphenylphosphirene was prepared via trapping of the phosphinidine complex Mo(CO)5PPh with diphenylacetylene.
Placement of the double bond between the carbon atoms provides a 1Hphosphirene in which the phosphorus center is bonded to two carbon atoms and a hydrogen atom. Alternatively, placement of the double bond between the phosphorus center and a carbon atom generates a 2H-phosphirene. The first 2H-phosphirene was synthesized as early as 1987 by Regitz group. However, the chemistry of 2H-phosphirenes was relatively dormant until a series of reports by Stephan group.
References
Phosphorus heterocycles
Three-membered rings
Hypothetical chemical compounds | Phosphirene | [
"Chemistry"
] | 279 | [
"Theoretical chemistry",
"Hypothetical chemical compounds",
"Hypotheses in chemistry"
] |
54,994,687 | https://en.wikipedia.org/wiki/Documenting%20Hate | Documenting Hate is a project of ProPublica, in collaboration with a number of journalistic, academic, and computing organizations, for systematic tracking of hate crimes and bias incidents. It uses an online form to facilitate reporting of incidents by the general public. Since August 2017, it has also used machine learning and natural language processing techniques to monitor and collect news stories about hate crimes and bias incidents. , over 100 news organizations had joined the project.
History
Origin
Documenting Hate was created in response to ProPublica's dissatisfaction with the quality of reporting and tracking of evidence of hate crimes and bias incidents after the United States presidential election of 2016. The project was launched on 17 January 2017, after the publication on 15 November 2016 of a ProPublica news story about the difficulty of obtaining hard data on hate crimes.
Introduction of the Documenting Hate News Index
On 18 August 2017, ProPublica and Google announced the creation of the Documenting Hate News Index, which uses the Google Cloud Natural Language API for automated monitoring and collection of news stories about hate crimes and bias incidents. The API uses machine learning and natural language processing techniques. The findings of the Index are integrated with reports from members of the public. The Index is a joint project of ProPublica, Google News Lab, and the data visualization studio Pitch Interactive.
Response
Participation
, thousands of incidents had been reported via Documenting Hate. , over 100 news organizations had joined the project, including the Boston Globe, the New York Times, Vox, and the Georgetown University Hoya.
Relationship to government statistical monitoring
A policy analyst for the Center for Data Innovation (an affiliate of the Information Technology and Innovation Foundation), while supporting ProPublica's critique of the present state of hate-crime statistics, and praising ProPublica for drawing attention to the problem, has argued that a nongovernmental project like Documenting Hate cannot solve it unaided; instead, intervention at the federal level is needed.
See also
Unite the Right rally
References
External links
Documenting Hate on ProPublica (www.documentinghate.com redirects to this ProPublica page)
Documenting Hate News Index
Google News Lab
Google Cloud Natural Language API
Pitch Interactive
Data mining
Data journalism
Hate crime
Knowledge bases
Media analysis organizations and websites
Natural language processing
Social statistics | Documenting Hate | [
"Technology"
] | 454 | [
"Natural language processing",
"Natural language and computing"
] |
55,000,798 | https://en.wikipedia.org/wiki/Minimal%20algebra | Minimal algebra is an important concept in tame congruence theory, a theory that has been developed by Ralph McKenzie and David Hobby.
Definition
A minimal algebra is a finite algebra with more than one element, in which every non-constant unary polynomial is a permutation on its domain. In simpler terms, it’s an algebraic structure where unary operations (those involving a single input) behave like permutations (bijective mappings). These algebras provide intriguing connections between mathematical concepts and are classified into different types, including affine, Boolean, lattice, and semilattice types.
Classification
A polynomial of an algebra is a composition of its basic operations, -ary operations and the projections. Two algebras are called polynomially equivalent if they have the same universe and precisely the same polynomial operations. A minimal algebra falls into one of the following types (P. P. Pálfy)
is of type , or unary type, iff , where denotes the universe of , denotes the set of all polynomials of an algebra and is a subgroup of the symmetric group over .
is of type , or affine type, iff is polynomially equivalent to a vector space.
is of type , or Boolean type, iff is polynomially equivalent to a two-element Boolean algebra.
is of type , or lattice type, iff is polynomially equivalent to a two-element lattice.
is of type , or semilattice type, iff is polynomially equivalent to a two-element semilattice.
References
Abstract algebra | Minimal algebra | [
"Mathematics"
] | 319 | [
"Abstract algebra",
"Algebra"
] |
55,002,259 | https://en.wikipedia.org/wiki/Non-canonical%20base%20pairing | Non-canonical base pairs are planar hydrogen bonded pairs of nucleobases, having hydrogen bonding patterns which differ from the patterns observed in Watson-Crick base pairs, as in the classic double helical DNA. The structures of polynucleotide strands of both DNA and RNA molecules can be understood in terms of sugar-phosphate backbones consisting of phosphodiester-linked D 2’ deoxyribofuranose (D ribofuranose in RNA) sugar moieties, with purine or pyrimidine nucleobases covalently linked to them. Here, the N9 atoms of the purines, guanine and adenine, and the N1 atoms of the pyrimidines, cytosine and thymine (uracil in RNA), respectively, form glycosidic linkages with the C1’ atom of the sugars. These nucleobases can be schematically represented as triangles with one of their vertices linked to the sugar, and the three sides accounting for three edges through which they can form hydrogen bonds with other moieties, including with other nucleobases. The side opposite to the sugar linked vertex is traditionally called the Watson-Crick edge, since they are involved in forming the Watson-Crick base pairs which constitute building blocks of double helical DNA. The two sides adjacent to the sugar-linked vertex are referred to, respectively, as the Sugar and Hoogsteen (C-H for pyrimidines) edges.
Each of the four different nucleobases are characterized by distinct edge-specific distribution patterns of their respective hydrogen bond donor and acceptor atoms, complementarity with which, in turn, define the hydrogen bonding patterns involved in base pairing. The double helical structures of DNA or RNA are generally known to have base pairs between complementary bases, Adenine:Thymine (Adenine:Uracil in RNA) or Guanine:Cytosine. They involve specific hydrogen bonding patterns corresponding to their respective Watson-Crick edges, and are considered as Canonical Base Pairs. At the same time, the helically twisted backbones in the double helical duplex DNA form two grooves, major and minor, through which the hydrogen bond donor and acceptor atoms corresponding respectively to the Hoogsteen and sugar edges are accessible for additional potential molecular recognition events.
Experimental evidences reveal that the nucleotide bases are also capable of forming a wide variety of pairing between bases in various geometries, having hydrogen bonding patterns different from those observed in canonical base pairs. These base pairs, which are generally referred to as Non-Canonical Base Pairs, are held together by multiple hydrogen bonds, and are mostly planar and stable. Most of these play very important roles in shaping the structure and function of different functional RNA molecules. In addition to their occurrences in several double stranded stem regions, most of the loops and bulges that appear in single-stranded RNA secondary structures form recurrent 3D motifs, where non-canonical base pairs play a central role. Non-canonical base pairs also play crucial roles in mediating the tertiary contacts in RNA 3D structures.
History
Double helical structures of DNA as well as folded single stranded RNA are now known to be stabilized by Watson-Crick base pairing between the purines, adenine and guanine, with the pyrimidines, thymine (or uracil for RNA) and cytosine. In this scheme, the N1 atoms of the purine residues respectively form hydrogen bond with the N3 atoms of the pyrimidine residues in A:T and G:C complementarity. The second hydrogen bond in A:T base pairs involves the N6 amino group of adenine and the O4 atom of thymine (or uracil in RNA). Similarly, the second hydrogen bond in G:C base pairs involves O6 atom and N4 amino group of guanine and cytosine, respectively. The G:C base pairs also have a third hydrogen bond involving the N2 amino group of guanine and the O2 atom of cytosine. However, even till about twenty years after this scheme was initially proposed by James D. Watson and Francis H.C. Crick, experimental evidences suggesting other forms of base-base interactions continued to draw the attention of researchers investigating the structure of DNA. The first high resolution structure of an adenine:thymine base pair, as solved by Karst Hoogsteen by single crystal X-ray crystallography in 1959 revealed a structure whose geometry was very different from what was proposed by Watson and Crick. It had two hydrogen bonds involving N7 and N6 atoms of adenine and N3 and O4 (or O2) atoms of thymine. It may be noted that due to use of thymine base with methyl group representing sugar, a symmetry axis appears passing through N1 and C6 atoms and the O2 and O4 atoms appears identical. In order to distinguish this alternate base pairing scheme from the Watson-Crick scheme, base pairs where a hydrogen bond involves the N7 atom of a purine residue have been referred to as Hoogsteen base pair, and later, the purine base edge which includes its N7 atom is referred to as its Hoogsteen edge. The first high resolution structure of guanine:cytosine pair, obtained by W. Guschelbauer also was similar to the Hoogsteen base pair, although this structure required an unusual protonation of N1 imino nitrogen of cytosine, which is possible only at significantly lower pH. Experimental evidences, including low resolution NMR studies as well as high resolution X-ray crystallographic studies, supporting Watson-Crick base pairing were obtained as late as in the early '70s. Almost a decade later, with the advent of efficient DNA synthesis methods, Richard Dickerson followed by several other groups, solved structures of the physiological double helical B-DNA with a complete helical turn, based on the crystals of synthetic DNA oligomers. The pairing geometries of the A:T (A:U in RNA) and G:C pairs in these structures confirmed the common or canonical form of base pairing as proposed by Watson and Crick, while those with all other geometries, and compositions, are now referred to as non-canonical base pairs.
It was noticed that even in double stranded DNA, where canonical Watson Crick base pairs associate the two complementary anti-parallel strands together, there were occasional occurrences of Hoogsteen and other non-Watson-Crick base pairs. It was also proposed that within Watson-Crick base pair dominated DNA double helices, Hoogsteen base pair formation could be a transient phenomenon.
While canonical Watson-Crick base pairs are most prevalent and are commonly observed in a majority of chromosomal DNA and in most functional RNAs, presence of stable non-canonical base pairs is also extremely significant in DNA biology. An example of non-Watson-Crick, or non-canonical, base pairing can be found at the ends of chromosomal DNA. The 3'-ends of chromosomes contain single stranded overhangs with some conserved sequence motifs (such as TTAGGG in most vertebrates). The single stranded region adopts some definite three-dimensional structures, which has been solved by X-ray crystallography as well as by NMR spectroscopy. The single strands containing the above sequence motifs are found to form interesting four stranded mini-helical structures stabilized by Hoogsteen base pairing between guanine residues. In these structures, four guanine residues form a near planar base quartet, referred to as G-quadruplex, where each guanine participates in base pairing with its neighboring guanine, involving their Watson-Crick and Hoogsteen edges in a cyclic manner. The four central carbonyl groups are often stabilized by potassium ions (K+). From the full genomic sequences of different organisms, it has been observed that telomere like sequences sometimes also interrupt double helical regions near transcription start site of some oncogenes, such as c-myc. It is possible that these sequence stretches form G-quadruplex like structures, which can suppress the expression of the related genes. The complementary cytosine rich sequences, on the other strand, may adopt another similar four stranded structure, the i-motif, stabilized by cytosine:cytosine non-canonical base pairs.
While non-canonical base pairs are still relatively rare in DNA, in RNA molecules, where generally a single polymeric strand folds onto itself to form various secondary and tertiary structures, the occurrence of non-Watson-Crick base pairs turns out to be far more prevalent. As early as in the 1970s, analysis of the crystal structure of yeast tRNAPhe showed that RNA structures possess significant non-canonical variations in base pairing schemes. Subsequently, the structures of ribozymes, ribosome, riboswitches, etc. have highlighted their abundance, and hence the need for a comprehensive characterization of Non-Canonical Base Pairs. These three-dimensional RNA structures generally possess several secondary structural motifs, such as double helical stems, stems with hairpin loops, symmetric and asymmetric internal loops, kissing loops between two hairpin motifs, pseudoknots, continuous stacks between two segments of helices, multi helix junctions etc. along with single stranded regions. These secondary structural motifs, except for the single stranded motifs, are stabilized by hydrogen bonded base pairs and several of these are non-canonical base pairs, including G:U Wobble base pairs.
It is notable in this context, that the Wobble hypothesis of Francis Crick predicted the possibility of G:U base pair, in place of the canonical G:C or A:U base pairs, also mediating the recognition between mRNA codons and tRNA anticodons, during protein synthesis. The G:U wobble base pair is the most numerously observed non-canonical base pair. While, because of its geometric similarity with the canonical base pairs, they frequently occur in the double helical stem regions of RNA structures, the geometric differences continue to draw the attention of nucleic acid researchers, providing new insights related to its structural significance. It may be noted that though the base pairs in the folded RNA structures, give rise to double helical stems, its two cleft regions – the major groove and minor groove, differ in their respective dimensions from those in DNA double helices. Unlike for those in DNA, the sequence discriminating major grooves in RNA double helices are very narrow and deep. On the other hand, the minor groove regions, though wide and shallow, do not carry much sequence specific information in terms of the hydrogen bonding donor-acceptor positioning of the corresponding base pair edges. The G:U wobble base pairs, along with the various other non-canonical base pairs, introduce variations in the structures of RNA double helices, thus enhancing the accessibility of the discriminating major groove edges of associated base pairs. This has been seen to be very important for molecular recognition steps during tRNA aminoacylation as well as in ribosome functions.
Considering the immense importance of the non-canonical base pairs in RNA structure, folding and functions, researchers from multiple domains – biology, chemistry, physics, mathematics, computer science, etc., have joined in the effort to understand their structure, dynamics, function and their consequences. The complexities associated with experimental handling of RNA further underline the importance of diverse theoretical inputs towards addressing these issues.
Types
Two bases may approach each other in various ways, eventually leading to specific molecular recognition mediated by, often non-canonical, base pairing interactions, in addition to strong stacking interactions. These are essential for the process of RNA single strands folding into three-dimensional structures. Early studies on such unusual base pairs by Jiri Sponer, Pavel Hobza and their group were somewhat disadvantaged due to the unavailability of suitable unambiguous systematic naming schemes. While some of the observed base pair were assigned names following the Saenger nomenclature scheme. others were arbitrarily assigned names by different researchers. It may be mentioned that some attempts were also made by Michael Levitt and coworkers to classify base-base association in terms of adjacency of bases, through either pairing or stacking interactions. There was clearly a need for a classification scheme for different types of non-canonical base pairs, which could comprehensively and unambiguously handle newer variants coming up due to the rapid increase in the sampling space. Different approaches which have evolved in response to this need are described below.
Based on hydrogen bonding
The nucleotide bases are nearly planar heterocyclic moieties, with conjugated pi-electron cloud, and with several hydrogen bonding donors and accepters distributed around the edges, usually designated as W, H or S, based on whether the edges can respectively be involved in forming Watson-Crick base pair, Hoogsteen base pair, or, whether the edge is adjacent to the C2’-OH group of the ribose sugar. Eric Westhof and Neocles Leontis used these edge designations to propose a currently widely accepted nomenclature scheme for base pairs. The hydrogen bonding donor and acceptor atoms could thus be classified in terms of their positioning along their three edges, namely the Watson-Crick or W edge, the Hoogsteen or H edge, and the Sugar or S edge. Since base pairs are mediated through hydrogen bonding interactions based on hydrogen bond donor-acceptor complementarity, this, in turn, provides a convenient bottoms-up approach towards classifying base pair geometries in terms of respective interacting edges of the participating bases. It may be noted that, unlike the Hoogsteen edge of purines, the corresponding edges of the pyrimidine bases do not have any polar hydrogen bond acceptor atom such as N7. However, these bases have C—H groups at their C6 and C5 atoms, which can act as weak hydrogen bond donors, as proposed by Gautam Desiraju. The Hoogsteen edge, hence, is also called Hoogsteen/C-H edge in a unified scheme for designating equivalent positions of purines as well as pyrimidines. Thus, the total number of possible edge combinations involved in base pairing are 6, namely Watson-Crick/Watson-Crick (or W:W), Watson-Crick/Hoogsteen (or W:H), Watson-Crick/Sugar (or W:S), Hoogsteen/Hoogsteen (or H:H), Hoogsteen/Sugar (or H:S) and Sugar/Sugar (or S:S).
In the canonical Watson-Crick base pairs, the glycosidic bonds attaching the N9 (of purine) and N1 (of pyrimidine) of the paired bases with their respective sugar moieties, are on the same side of the mean hydrogen bonding axis, and are hence called Cis Watson-Crick base pairs. However, the relative orientations of the two sugars may also be Trans with respect to the mean hydrogen bonding direction giving rise to a distinct Trans Watson-Crick geometric class, consisting of species which were earlier referred to as reverse Watson-Crick base pairs according to Saenger nomenclature. The possibility of both Cis and Trans glycosidic bond orientation for each of the 6 possible edge combinations, gives rise to 12 geometric families of base pairs (see table).
According to the Leontis-Westhoff scheme, any base pair can be systematically and unambiguously named using the syntax <Base_1: Base_2><Edge_1: Edge_2><Glycosidic Bond Orientation> where Base_1 and Base_2 carry information on respective base identities and their nucleotide number. This nomenclature scheme also allows us to enumerate the total number of distinct possible base pair types. For a given glycosidic bond orientation, say Cis, the four naturally occurring bases each have three possible edges for formation of base pairs giving rise to 12 such possible base pairing edge identities, each of which can in principle form base pairing with any edge of another base, irrespective of complementarity. This gives rise to a 12x12 symmetric matrix displaying 144 pairwise permutations of base pairing edge identities, where, apart from the 12 diagonal entries, others include repeat combinations. Thus, there are 78 (= 12 + 132/2) unique entries corresponding to the cis glycosidic bond orientation. Considering both cis and trans glycosidic bond orientations, the number of base pair types amounts to 156.
Of course, this number 156 is only an indicator. It includes base-edge combinations where base pairs cannot be formed due to absence of hydrogen bond donor acceptor complementarities. For example, potential pairing between two guanine residues utilizing their Watson-Crick edges in cis form (cWW) is not supported by hydrogen bonding donor-acceptor complementarity, and is not observed with consistent hydrogen bonding pattern. This method of enumerating the possible number of distinct base pair types also does not consider possibilities of multimodality or bifurcated base pairs, or even instances of base pairs involving modified bases, protonated bases and water or ion mediation in hydrogen bond formation. Two cytosine bases can form trans Watson-Crick/Watson-Crick (tWW) base pairing with their neutral as well as hemi protonated forms, possibly both, giving rise to the i-motif DNA. However, both C(+):C tWW and C:C tWW, are counted as one type among 156 possible types.
Based on isosteres
Although significant differences are there between structures of non-canonical base pairs belonging to different geometric families, some base pairs within the same geometric family have been found to substitute each other without disrupting the overall structure. These base pairs are called isosteric base pairs. Isosteric base pairs always belong to same geometric families, but all the base pairs in a particular geometric family are not always isosteric. Two base pairs are called isosteric if they meet the following three criteria: (i) The C1′–C1′ distances should be similar; (ii) the paired bases should be related by the similar rotation in 3D space; and (iii) H-bonds formation should occur between equivalent base positions. A detailed approach towards quantifying isostericity, in terms of an IsoDiscrepancy Index (IDI), which can facilitate reliable prediction regarding which base pair substitutions can potentially occur in conserved motifs, was formulated by Neocles Leontis, Craig Zirbel and Eric Westhof. Based on IDI values and available base pair structural data, the group maintains a curated online base pair catalogue and an updated set of Isostericity Matrices (IM) corresponding to each of the 12 geometric families. Using this resource, one can comprehensively classify different types of canonical and non-canonical base pairs in terms of their positions in the Isostericity Matrices. This approach, for example, indicates that the four base pair types: A:U cWW, U:A cWW, G:C cWW and C:G cWW are isosteric to each other. Thus, as also confirmed by detailed sequence comparisons, double mutations altering A:U cWW to U:A cWW or even to G:C cWW may not disturb the structure, and, unless stability issues are involved, the function of the related RNA. It was also found that the wobble G:U cWW base pair is not really isosteric to U:G cWW base pair, indicating that such double mutations may significantly affect the functioning of the corresponding RNA. On the other hand, some of the base pairs which are stabilized involving Sugar edge of the bases are mutually isosteric.
Based on local strand direction
It may be noted here that because of the geometric relationship of the bases with the sugar phosphate backbone, these 12 geometric families of base pairs are associated with two possible local strand orientations, namely parallel and antiparallel. For the 6 families with edge combinations involving Watson-Crick and Sugar edges, W:W, W:S and S:S, cis and trans families are respectively associated with antiparallel and parallel 5' to 3' local strand direction. Introduction of the Hoogsteen edge, as one of the partners in the combination, causes an inversion in the relationship. Thus, for W:H and H:S, cis and trans respectively correspond to parallel and antiparallel local strand orientation. As expected, when both the edges are H, a double inversion is observed, and H:H cis and trans correspond respectively to antiparallel and parallel local strand orientations. The annotation of local strand orientation in terms of parallel and antiparallel directions helps to understand which faces of the individual bases can be seen for a given base pair from the 5’- or the 3’ sides. This annotation also helps in classifying the 12 geometries into two groups of 6 each, where the geometries can potentially interconvert within each group, by in-plane relative rotation of the bases. However, one should note that the above theory is applicable only when the glycosidic torsion angles of both the nucleotide residues are anti. Notably, crystallographic observations and energetic considerations indicate that syn glycosidic torsions are also quite possible. Hence the above classification of parallel or antiparallel nature of strand directions, by itself, does not always provide the complete understanding.
Various functional RNA molecules are stabilized, in their specific folded pattern, by both canonical as well as non-canonical base pairs. Most tRNA molecules, for example, are known to have four short double helical segments, giving rise to a cloverleaf like two-dimensional structure. The three-dimensional structure of tRNA, however, takes an L-shape. This is mediated by several non-canonical base pairs and base triplets. The D-loop and TψC loop are held together by several such base pairs. There is a variety of non-canonical base pair varieties, which can be browsed through different websites such as NDB, RNABPDB, RNABP COGEST, etc., to get a better understanding.
It may be noted that the above scheme is valid for naturally occurring nucleotide bases. However, there are plenty of examples of post-transcriptional chemical modifications of the bases, many of which are seen in tRNAs or ribosomes. It may be important to understand their structural features also.
Identification
In case of double helical DNA, identification of base pairs is quite trivial using molecular visualizers such as VMD, RasMol, PyMOL etc. It is, however, not so simple for single stranded folded functional RNA molecules. Several algorithms have been implemented in software tools for the automated detection of base pairs in RNA structures solved by X-ray crystallography, NMR or other methods. Essentially the programs detect hydrogen bonds between two bases, and ensure their (near) planar orientation, before reporting that they constitute a base pair. Since most of the structures of RNA, available in public domain, are solved by X-ray crystallography, the positions of hydrogen atoms are rarely reported. Hence, detection of hydrogen bond becomes a non-trivial job.
The DSSR algorithm by Lu and Wilma K. Olson considers two bases to be paired when they detect one or more hydrogen bond(/s) between the bases, by actually modeling the positions of the hydrogen atoms, and by ensuring the perpendiculars to the two bases being nearly parallel to each other. The positions of the hydrogen atoms can be deduced by converting Internal Coordinates (bond length, bond angle and torsion angle) along with positions of precursor atoms, such as amino group nitrogen atoms and those bonded to the nitrogen or Z-matrix to external Cartesian Coordinates. The base pairs identified by this method are listed in NDB and FR3D databases.
A unique way of identification of base pairs in RNA was incorporated in MC-Annotate by Francois Major. In this algorithm they make use of the positions of the hydrogen atoms as well as lone-pair electrons using suitable molecular mechanics/dynamics force-fields and derive hydrogen bond formation probabilities for them. The final identifications of base pairs are done based on these probabilities and approach of hydrogen atoms to lone-pairs electrons of nitrogen or oxygen. This method also attempted to classify the base pair nomenclature with additional information of each interacting edge, such as Ws indicating the sugar edge corner of the Watson-Crick edge, Wh representing the Hoogsteen edge corner of Watson-Crick edge, Bw indicating bifurcated three-center hydrogen bond involving both the hydrogen atoms of amino groups to form hydrogen bonds with a carbonyl oxygen involving both of its lone-pairs, etc. As claimed by the authors, this nomenclature scheme adds some additional features to the Leontis-Westhof (LW) scheme and may be referred to as the LW+ scheme. A major advantage of this scheme lies in its ability to distinguish between alternative base pairing geometries, where multimodality is observed within an LW family. This method, however, does not consider the possible participation of the 2'-OH group of the ribose sugars in base pair formation.
Another algorithm, namely BPFIND by Dhananjay Bhattacharyya and coworkers, demands at least two hydrogen bonds using two distinct sets of donors and acceptors atoms between the bases. This hypothesis driven algorithm considers distances between two pairs of atoms (hydrogen bond donor (D1 and D2) and acceptor (A1 and A2) and four suitably chosen precursor atoms (PD1, PD2, PA1, PA2) corresponding to the D's and A's. Small values of such distances in conjunction with large values of the angles defined by θ1(PD1—D1—A1), θ2(D1—A1—PA1), θ3(PD2—D2—A2), θ4(D2—A2—PA2) (close to 180o or πc) ensures two structural features which characterize well defined base pairs: i) the hydrogen bonds are strong and linear and ii) the two bases are co-planar. Notably, so long as one restricts the search to base pairs which are stabilized by at least two distinct hydrogen bonds, the above algorithms, by and large, yield the same set of base pairs in different RNA structures.
Sometimes in the crystal structures it is observed that two closely spaced bases are oriented in such a way that apart from the regular hydrogen bonds two additional electronegative hydrogen bond acceptor atoms are very close to each other, which may cause electrostatic repulsion. The concept of protonated base pairing, implicating a possible protonation of one of these electronegative, (potentially) hydrogen bond acceptor atoms thus converting it into a hydrogen bond donor, was introduced to explain stability of such geometries. Some of the NMR derived structures also support the protonation hypothesis, but possibly more rigorous studies using neutron diffraction or other techniques would be able to confirm it. The quality of the crystal structures permitting, some algorithms also attempted to detect water or cation mediated base pair formation.
Stability
The canonical Watson-Crick base pairs, G:C and A:T/U as well as most of the non-canonical ones are stabilized by two or more (e.g. 3 in the case of G:C cWW) hydrogen bonds. Justifiably, a significant amount of research on non-canonical base pairs has been carried out towards bench-marking their strengths (interaction energies) and (geometric) stability against those of the canonical base pairs. It may be noted here that base pair geometries, as observed in the crystal structures, are often influenced by several interactions present in the crystal environment, thus perturbing their intrinsically stable geometries arising out of the hydrogen bonding and related interactions between the two bases. Therefore, in principle, it is possible that the observed geometries in some cases are intrinsically unstable, and that they are stabilized by other interactions provided by the environment. Several groups have attempted to determine the interaction energies in these non-canonical base pairs using different quantum chemistry based approaches, such as Density functional theory (DFT) or MP2 methods. These methods were applied on suitably truncated, hydrogen-added, and geometry optimized models of the base (or nucleoside) pairs extracted from PDB structures. Depending upon the optimization protocol, typically three types of interaction energies have been reported. In the first method, the base pair model geometries, isolated from their respective environments, are fully optimized without any constraints. thus providing the intrinsic geometries and interaction energies of the isolated models. This procedure, however, sometimes leads to optimized geometries of base pairs involving edges different from initial crystal geometry. Abhijit Mitra and collaborators also used an additional second protocol, where the heavy atom (non-hydrogen) coordinates are retained as in the crystal geometries, optimizing only the positions of the added hydrogen atoms. In the third protocol, followed mostly by Jiri Sponer and his group, optimization was carried out with constraints on some angles and dihedrals. Given that the models are extracted from their respective crystal structures, and are isolated from their crystal environments, the second and the third protocols provide two different approaches towards approximating the environmental effects, without explicit considerations of any specific environmental interactions. This has further been addressed in some reports by considering specific environmental factors, such as coordination with Magnesium, or even some covalent modifications to the bases.
All the three protocols are useful in their respective contexts. Further, a comparison of the model geometries, obtained by the different protocols, provide an idea regarding both, the stability of the corresponding base pair geometries, as well as regarding the probable extent and nature of environmental influences. It was found that most non-canonical base pairs, having two or more hydrogen bonds, generally maintain the same hydrogen bonding pattern in the crystal and in fully optimized in isolation geometries, respectively, thus indicating their intrinsic geometric stability. Interaction energies calculated from these optimized models also indicated the energetic stability of the corresponding non-canonical base pairs. The previous notion that non-canonical base pairs are weaker than the Watson-Crick base pairs, was found to be incorrect. Interaction energies between the bases of Several base pairs, such as G:G tWW, G:G cWH, A:U cHW, G:A cWW, G:U cWW, etc., are found to be larger than that of canonical A:U cWW base pair.
Of course all non-canonical base pairs are not necessarily very strong or stable in terms of interaction energy. Several base pairs have been detected on the basis of weak hydrogen bonds involving C—H...O/N atoms, where interaction energies are rather small. Further, geometry optimizations of some of the observed base pairs, in particular, but not limited to those involving weak hydrogen bonds, or those stabilized by single hydrogen bonds, were found to adopt alternate geometries, thus indicating their intrinsic lack of geometric stability. These alteration of hydrogen bonding schemes, giving rise to changes in base pairing family upon free optimization, may have some functional implication in RNA, such as their action as conformational switch. Accordingly, as mentioned above in the Sponer's protocol, there have been some attempts to restrain the experimentally observed geometry while carrying out geometry optimization for interaction energy calculations. Interestingly, in several cases, interaction energies calculated for these ‘away from intrinsically stable’ geometries also indicate good energetic stability.
Though the energetics and geometric stabilities of different non-canonical base pairs do not show any generalized correlations, analysis of several databases, such as RNABPDB and RNABP COGEST, which catalogue structural and energetic features of some of the observed base pair and their stacks, reveal some interesting general trends.
For example, geometry optimizations of several base pairs involving 2’-OH group of sugar residue resulted in significant alterations from their initial geometry. This is possibly due to flexibility of the sugar puckers and glycosidic torsions. The significantly high interaction energies of protonated base pairs, despite the high energy cost of base protonation, also deserve a special mention in this context. This can mostly be attributed to the additional charge-induced dipole interactions which are associated with protonated base pairs.
Structure
Base pairing
An estimated 60% of bases in structured RNA participate in canonical Watson-Crick base pairs. Base pairing occurs when two bases form hydrogen bonds with each other. These hydrogen bonds can be either polar or non-polar interactions. The polar hydrogen bonds are formed by N-H...O/N and/or O-H...O/N interactions. Non-polar hydrogen bonds are formed between C-H...O/N.
Edge interactions
Each base has three potential edges where it can interact with another base. The Purine bases have 3 edges which are able to hydrogen bond. Those are known as the Watson-Crick edge(WC), the Hoogsteen edge(H), and the Sugar edge(S). Pyrimidine bases also have three hydrogen-bonding edges. Like the purine, there is the Watson-Crick edge(WC) and the Sugar edge(S) but the third edge is referred to as the "C-H" edge(H) on the pyrimidine bases. This C-H edge is sometimes also referred to as the Hoogsteen edge for simplicity. The various edges for the purine and pyrimidine bases are shown in Figure 2.
Besides the three edges of interaction, base pairs can also vary in their cis/trans forms. The cis and trans structures depend on the orientation of the ribose sugar as opposed to the hydrogen bond interaction. These various orientations are shown in Figure 3. Therefore, with the cis/trans forms and the 3 hydrogen bond edges, there are 12 basic types of base pairing geometries which can be found in RNA structures. Those 12 types are WC:WC (cis/trans), WC:HC (cis/trans), WC:S (cis/trans), H:S (cis/trans), H:H (cis/trans), and S:S (cis/trans).
Classification
These 12 types can be further divided into more subgroups which are dependent on the directionality of the glycosidic bonds and steric extensions. With all of the various base pair combinations there are 169 theoretically possible base pair combinations. The actual number of base-pair combinations is lower because some combinations result in non-favorable interactions. This number of possible non-canonical base pairs is still being determined as it depends strongly on base pairing criteria . Understanding base pair configuration is similarly difficult since the pairing is depends on the bases surroundings. These surroundings can consist of adjacent base pairs, adjacent loops, or third interactions (such as a base triple).
The bonds between various bases are well defined because of their rigid and planar shape. The spatial interactions between the two bases can be classified in 6 rigid-body parameters or intra-base pair parameters (3 translational, 3 rotational) as shown in Figure 4. These parameters describe the base pairs' three dimensional conformation.
The three translational arrangements are known as shear, stretch, and stagger. These three parameters are directly related to the proximity and direction of the hydrogen bonds. The rotational arrangements are buckle, propeller, and opening. Rotational arrangements relate to the non-planar confirmation (as compared to the ideal coplanar geometry). Intra-base pair parameters are used to determine the structure and stabilities of non-canonical base pairs and were originally created for the base pairings in DNA, but were found to also fit the non-canonical base models.
Types
The most common non-canonical base pairs are trans A:G Hoogsteen/sugar edge, A:U Hoogsteen/WC, and G:U Wobble pairs.
Hoogsteen base pairs
Hoogsteen base pairs occur between adenine (A) and thymine (T); and guanine (G) and cytosine(C); similarly to Watson-Crick base pairs. However, the purine (A and G) takes on an alternative conformation with respect to the pyrimidine. In the A-U Hoogsteen base pair, the adenine is rotated 180° about the glycosidic bond, resulting in an alternative hydrogen bonding scheme which has one hydrogen bond in common with the Watson-Crick base pair (adenine N6 and thymine N4), while the other hydrogen bond, instead of occurring between adenine N1 and thymine N3 as in the Watson-Crick base pair, occurs between adenine N7 and thymine N3. The A-U base pair is shown in Figure 5. In the G-C Hoogsteen base pair, like the A-T Hoogsteen base pair, the purine (guanine) is rotated 180° about the glycosidic bond while the pyrimidine (cytosine) remains in place. One hydrogen bond from the Watson-Crick base pair is maintained (guanine O6 and cytosine N4) and the other occurs between guanine N7 and a protonated cytosine N3 (note that the Hoogsteen G-C base pair has two hydrogen bonds, while the Watson-Crick G-C base pair has three).
Wobble base pairs
Wobble base pairing occur between two nucleotides that are not Watson-Crick base pairs and was proposed by Watson in 1966. The 4 main examples are guanine-uracil (G-U), hypoxanthine-uracil (I-U), hypoxanthine-adenine (I-A), and hypoxanthine-cytosine (I-C). These wobble base pairs are very important in tRNA. Most organisms have less than 45 tRNA molecules even though 61 tRNA molecules would technically be necessary to canonically pair to the codon. Wobble base pairing allows for the 5' anticodon to bond to a non-standard base pair. Examples of wobble base pairs are given in Figure 6.
3-D Structure
The secondary and three-dimensional structures of RNA are formed and stabilized through non-canonical base pairs. Base pairs make up many secondary structural blocks which aid the folding of RNA complexes and three dimensional structures. The overall folded RNA is stabilized by the tertiary and secondary structures canonically base pairing together. Due to the many possible non-canonical base pairs, there are an unlimited amount of structures, which allows for the diverse functions of RNA. The arrangement of the non-canonical bases also allow long-range RNA interactions, recognition of proteins and other molecules, and structural stabilizing elements. Many of the common non-canonical base pairs can be added to a stacked RNA stem without disturbing its helical character.
Secondary
Basic secondary structural elements of RNA include bulges, double helices, hairpin loops, and internal loops. An example of a hairpin loop of RNA is given in Figure 7. As shown in the figure, hairpin loops and internal loops require a sudden change in backbone direction. Non-canonical base pairing allows for the increased flexibility at junctions or turns required in the secondary structure.
Tertiary
Three-dimensional structures are formed through the long-range intra-molecular interactions between the secondary structures. This leads to the formation of pseudoknots, ribose zippers, kissing hairpin loops, or co-axial pseudocontinuous helices. The three-dimensional structures of RNA are primarily determined through molecular simulations or computationally guided measurements. An example of a Pseudoknot is given in Figure 8.
Structural features of a base-pair, formed by two planar rigid units, can be quantified, using six parameters – three translational and three rotational. IUPAC recommended parameters are Propeller, Buckle, Open Angle, Stagger, Shear and Stretch (Figure 8). There are several publicly available software, such as Curves by Richard Lavery, 3DNA by Olson, NUPARM by Manju Bansal, etc., which may be used to calculate these parameters. While the first two calculate the parameters of canonical and non-canonical base-pairs relative to the standard canonical Watson-Crick base pairs geometry, the NUPARM algorithm calculates in absolute terms using base pairing edge specific axis system. Hence, for most non-canonical base-pairs, which involve non-Watson-Crick edges, some of the parameters (Open, Shear and Stretch) calculated by Curves or 3DNA are usually large even in their respective intrinsically most stable geometries. On the other hand, the values provided by NUPARM indicate the quality of hydrogen bonding and planarity of the two bases in a more realistic fashion. Thus, the NUPARM Stretch values, indicating separation of the two bases of a base pair, and which depend on optimal hydrogen bonding distances, are always around 3Ǻ. Some other general trends observed in the values of the above parameters may be of interest to note. Most of the cis base pairs are seen to have Propeller values around -10o and small values of Buckle and Stagger. The Open and Shear values often depend on positions of the hydrogen bonding atoms. As for example, GU cWW wobble base pairs have Shear value around -2.2Ǻ while GC or AU cWW base pairs have Shear values around zero. The Open values for most base pairs are close to zero but the values are often rather large for those involving 2’-OH group of sugar in the NUPARM derived parameter set. The trans base pairs, however, do not show any systematic trend in their Propeller values.
Roles
In RNA
The structural hierarchy in RNA is usually described in terms of a stem-loop 2D secondary structure, which further folds to form its 3D tertiary structure, stabilized by what are referred to as long range tertiary contacts. Most often the non-canonical base pairs are involved in those tertiary contacts or extra-stem base pairs. For example, some of the non-canonical base pairs in tRNA appear between the D-stem and TψC loops (Figure 5), which are close in the three-dimensional structure. Such base pairing interactions give stability to the L-shaped structure of tRNA. In this region, some base pairs are found to be additionally hydrogen bonded to a third base. Thus, the 23rd residue is simultaneously paired to 9th and 12th residues, together forming a base triple, the smallest member of the class of higher order multiplets.
Multiplets
One base, in addition to forming proper planar base pairing with a second base, can often participate in base pair formation with a third base forming a base triple. One such classic example is in formation of DNA triple helix, where two bases of two antiparallel strands form consecutive Watson-Crick base pairs in a double helix and a base of a third strand form Hoogsteen base pairing with the purine bases of the Watson-Crick base pairs. Many different types of base triples have been reported in the available RNA structures and have been elegantly classified in the literature. Multiplets are however not limited to triplet formation. Four bases giving rise to a base quartet is now well documented in the structure of the G-quadruplex characteristically found in the telomere. Here four Guanine residues pair up within themselves in a cyclic form involving Watson-Crick/Hoogsteen cis (cWH) base pairing scheme and each of the Guanine bases are found to be respectively interact with two other guanine bases. Three to four such base G-quadruplexes stack on top of the other to form a four stranded DNA structure. In addition to such a cyclic topology, several other topologies of base:base pairings are possible for higher order multiplets such as quartets, pentets etc.
Double helical regions
Non-canonical base pairs quite frequently appear within double helical regions of RNA. The G:U cWW non-canonical base pairs are seen very frequently within double helical regions as this base pair is nearly isosteric to the other canonical ones. Due to complication of strand direction, as elaborated in the Classification section (Table 1), not all types of non-canonical base pairs can be accommodated within double helical regions with anti glycosidic torsion angles. However, many non-canonical base pairs, e.g. A:G tHS (trans Hoogsteen/Sugar edge) or A:U tHW (trans Hoogsteen/Watson-Crick), A:G cWW, etc., are often seen within double helical regions giving rise to symmetric internal loop like motifs. Attempts have been made to classify all such situations where two base pairs (canonical or non-canonical) stack in anti-parallel sense possibly giving rise to double helical regions in RNA structures. These base pairs are quite stable, and they are able to maintain the helical property quite well. The backbone torsion angles around these residues are also generally within reasonable limits: C3'-endo sugar pucker with anti glycosidic torsion, α/γ torsion angles around -60o/60o, β/ε torsion angles around 180o.
Recurrent structural motifs
Non-canonical base pairs often appear in different structural motifs, including pseudoknots, with their special hydrogen bonding features. Structural features of these recurrent motifs have been archived in searchable databases, such as, FR3D and RNA FRABASE. Also, several of these motifs can be identified in a given query PDB file by the NASSAM web-server. They are most frequently detected at the termini of double helical segment acting as capping residues, often preceding hairpin loops. The most frequently found non-canonical base pair, namely G:A tSH, is an integral part of GNRA tetraloops, where N can be any nucleotide residue and R is a purine residue. This motif shows some amount of flexibility and alterations of structural features depending on whether the Guanine and Adenine are paired or not. Several other types of tetraloops motifs, such as UNCG, YNMG, GNAC, CUYG, (where Y stands for pyrimidine and M is either Adenine or Cytosine) etc., have been found in available RNA structures. However, these do not generally show involvement of non-canonical base pairing. In addition to these common hairpin motifs, where the loop residues largely remain unpaired, there are also a few motifs where the loop residues make extensive interactions between themselves or with other residues external to the loop. A common example is the C-loop motif, where the bulging loop residues make non-canonical base pairing with the bases of double helical regions forming non-canonical base pairing (Figure 9). The extra base pairs in these cases give rise to additional stabilization to the composite double helix containing motif. Non-canonical base pairs are also involved in receptor-loop interaction, such as in T-loop motif. Another interesting example of the involvement of non-canonical base pairs in recurrent contexts was detected as the GAAA receptor motif, which consists of A:A cHS base pair followed by U:A tWH base pair stacked on both sides by G:C cWW base pairs. Here we have successive non-canonical base pairs within an antiparallel RNA double helical domain. Similarly there is an A:A cSH base pair involving two consecutive residues in this motif. Such pairing between consecutive residues, which is also termed as a dinucleotide platform motif, is quite commonly observed. They appear in many RNA structures and the pairing can also be between other bases. Such dinucleotide platform was reported in A:A, A:G, A:U, G:A, G:U base pairs belonging to the cSH class and also in A:A cHH base pairs. These motifs can alter the strand direction within a double helix by formation of kinks. Such dinucleotide platform along with triplet formation is also an integral component of the Sarcin-ricin motif.
Modeling
Prediction of biomolecular structure from sequence alone is a long-term goal of scientists working in the fields of bioinformatics, computational chemistry, statistical physics as well as in computer science. Prediction of protein structures from amino acid sequence by methods like homology modeling, comparative modeling, threading, etc. were largely successful due to availability of about 1200 unique protein folds. Inspired by the protein experience, there are now several approaches towards predicting RNA structures, albeit with varying degrees of success.
It can be seen that most of the approaches are essentially limited to the prediction of RNA 2D stem-loop structure, also referred to as RNA secondary structure. For example, minimum computed free energy prediction of double helical regions of RNA sequences from the energy of base pairing and stacking interactions, essentially computationally derived from experimental thermodynamic data, was initially introduced by Ruth Nussinov and later by Michael Zuker. This, in turn, has inspired several related modified algorithms, including data on neighboring group interactions etc. Most of these approaches, however, mainly consider data on canonical base pairing, with only a few which also consider thermodynamic data on Hoogsteen base pairs. Thus, in addition to the computational costs and complications associated with the identification of pseudoknots, all these methods also suffer from the drawback associated with the paucity of experimental data on non-canonical base pairs.
However, there are also several approaches which attempt at predicting the tertiary 3D structure corresponding to given predicted 2D structures. There are also a few involving 3D fragment based modeling, which are getting further facilitated with the increasing availability of motif wise curated RNA 3D structure data. It is also encouraging to note that there are now some software and servers, such as MC-Fold, RNAPDBee, RNAWolfe, etc. available for exploring non-canonical base pairing in RNA 3D structures. Some of these methods depend on structural database of RNA, such as FRABASE, to obtain 3D coordinates of motifs containing non-canonical base pairs and stitch the information with 3D structure of double helices containing canonical base pairs.
It may be relevant in this context, to mention about the approach towards 3D model building of double helical regions with both canonical and non-canonical base pairs used in 3DNA by Olson or in RNAHelix by Bhattacharyya and Bansal. These software suites use base pair parameters to generate 3D coordinates of individual dinucleotide steps, which can be extended to model double helices of arbitrary lengths with canonical or non-canonical base pairs.
The above-mentioned methods attempt to model a single structure (2D or 3D) of a given RNA sequence. However, growing evidences indicate that a given RNA sequence can adopt ensemble of structures and possibly interconvert between them. This ensembles obviously adopt different base pairing patterns between different sets of residues. Thus, there are enough pointers to suggest that the focus on modeling single structures appears to have been a bottleneck for accurate modeling of RNA structure.
The theoretical prediction of RNA 2D structure and consequently 3D structure can also be confirmed by different chemical probing methods. One of the latest such tools is SHAPE (Selective 2′-hydroxyl acylation analyzed by primer extension), and SHAPE-Directed RNA Secondary Structure Prediction appears to be most promising. Coupled with mutational profiling, ensembles of RNA structures, which often include non-canonical base pairing, can be experimentally studied using the SHAPE-MaP approach. One of the ways ahead today appears to be an integration of Zuker's minimum free energy approach with experimentally derived SHAPE data, including simulated SHAPE data as outlined in Montaseri et al. (2016) and Spasic et al. (2017).
See also
Hoogsteen base pair
Wobble base pair
References
Molecular genetics
Nucleic acids | Non-canonical base pairing | [
"Chemistry",
"Biology"
] | 10,917 | [
"Biomolecules by chemical classification",
"Nucleic acids",
"Molecular genetics",
"Molecular biology"
] |
55,002,968 | https://en.wikipedia.org/wiki/Haldia%20Multi-Modal%20Terminal | The Haldia Multi-Modal Terminal is a inland-terminal in Port City Haldia in East Midnapore district of West Bengal and a small barrier set for small ships. The terminal is built near the Haldia Port. The terminal built as a inland-river port with 61 acres of land. The terminal is built by Inland Waterways Authority of India by help of West Bengal and the Calcutta Port Trust.
Cargo is handled through flyash berths and multi-purpose berths located within the terminal's jetty. It have a maximum depth of and able big barge. According to the Inland Waterways Authority of India, the draft of the port is around with tidal support, which accommodate 3,000 DWT (deadweight tonnage) vessels at the terminal's jetty.
Background
Due to the shortage of pontoon transport through the waterway, the government of India has decided to transport the commodity to the waterways as compared to the road and railways. For this, the government announced that the goods will be transported from Haldia to Allahabad by sea. For this, the government began to build uplines for small ships or barges in the Hooghly and Ganges rivers. It is said from the government that the terminals will be constructed in Haldia Sahebganj and Varanasi for shipping the goods through the waterway. To this end, construction of multi-modal terminals in Haldia began.
Terminal details
harbour
The harbour of the terminal has a natural harbor, which is protected by balari sandbar. The water depth of the harbour basin is , which accommodate large barges. The approach channel forms a turning circle with diameter in the harbour with a depth of , which is used to change the direction of the vessel as required before berthing the vessel at the jetty.
Approach channel
The approach channel connects the deep water body to the harbour, Which is constructed by dredging the riverbed from to deep. An 7 kilometers long approach channel at river will be used for the movement of barges to the terminal's jetty. The approach channel has a depth of and a minimum width of 45 meters, allowing vessels with a draft of to arrive and depart the harbor without tidal assistance. However, the highest and lowest tides observed in the harbor area are and meters respectively, which can significantly increase the depth of the approach channel. At high tide the channel more than deep with tidal support; vessels with a draft of or more are able to navigate during this period.
Transport of product
The proposed Haldia multipurpose terminal in West Bengal will become a major hub for the transportation of goods in West Bengal and north-east India. The terminal has the promise and potential of 5.92 MMPPA freight traffic by 2018.The main products that will be transported through this terminal include fly ash, banaspati oil, cement etc.
See also
National Waterway 1
Varanasi Multi-Modal Terminal
Sahebgang Multimodal Terminal
References
Bibliography
External links
Ports and harbours of West Bengal
Ports and harbours of India
River ports of India
Transport in Haldia
Intermodal transport
Proposed ports in India | Haldia Multi-Modal Terminal | [
"Physics"
] | 626 | [
"Physical systems",
"Transport",
"Intermodal transport"
] |
55,003,162 | https://en.wikipedia.org/wiki/Infant%20crying | Infant crying is the vocalizations of infants as a response to an internal or external stimulus. Infants cry as a form of basic instinctive communication. Essentially, newborns are transitioning from life in the womb to the external environment. Up to 27% of parents describe problems with infant crying in the first four months. Up to 38% identify a problem with their infant crying within the first year. Parents can be concerned about the amount of time that their infant cries, how the infant can be consoled, and disrupted sleeping patterns. Colic is used as a synonym for excessive crying of infants, even though colic may not be the cause of excessive crying.
Physiology
Crying may elicit the Valsalva reflex. This reflex negatively impacts sucking pressures and results in poor feeding. The cortisol levels will rise along with blood pressure. Increased blood pressure will have an effect on cerebral blood flow, cerebral blood flow velocity and intracranial pressure. Increased pressures and velocity can lead to intracranial hemorrhage. Prolonged exhalation may also cause some adverse effects. Obstructed venous return and quick inspiratory gasp can occur. Foramen ovale shunting can occur. Adults can often determine whether an infant's cries signify anger or pain. Most parents can distinguish their own infant's cries from those of a different child. Babies mimic their parents' pitch contour. French infants wail on a rising note while German infants favor a falling melody. Overstimulation may be a contributing factor to infant crying and that periods of active crying might serve the purpose of discharging overstimulation and helping the baby's nervous system regain homeostasis.
Although crying is an infant's mode of communication, it is not limited to a monotonous sound. There are three different types of cries apparent in infants. The first of these three is a basic cry, which is a systematic cry with a pattern of crying and silence. The basic cry starts with a cry coupled with a briefer silence, which is followed by a short high-pitched inspiratory whistle. Then, there is a brief silence followed by another cry. Hunger is a main stimulant of the basic cry. An anger cry is much like the basic cry; in this cry, more excess air is forced through the vocal cords, making it a louder, more abrupt cry. This type of cry is characterized by the same temporal sequence as the basic pattern but distinguished by differences in the length of the various phase components. The third cry is the pain cry, which, unlike the other two, has no preliminary moaning. The pain cry is one loud cry, followed by a period of breath holding.
Misconceptions
Misconceptions regarding the purpose of crying in the infant are common among caregivers and medical personnel. These are usually determined by cultural mores and not by evidence-based explanations. Infant crying is regarded by some to be normal. The belief that infants have a need to cry to expand or exercise their lungs is not supported by research. This is because a healthy newborn infant lung's are able to contain a sufficient amount of air plus a reserve. Birth trauma is related to the amount of crying. Mothers who had experienced obstetrical interventions or who were made to feel powerless during birth had babies who cried more than other babies. Babies who had experienced birth complications had longer crying spells at three months of age and awakened more frequently at night crying. When infants cry for no obvious reason after all other causes (such as hunger or pain) are ruled out, the crying may signify a beneficial stress-release mechanism, although not all sources agree with this. The "crying-in-arms" approach is a way to comfort these infants. Another way of comforting and calming the baby is to mimic the familiarity of the mother's womb. Consistency and promptness of maternal response is associated with a decline in frequency and duration of crying by the end of the first year, and individual differences in crying reflect the history of maternal responsiveness rather than constitutional differences in infant irritability.
Causes
Most infants cry in response to something, although it may be difficult to identify the cause. Sometimes there may be no apparent reason.
Some possible reasons include:
Hunger
Sleepiness (Normally just yawns or rubs eyes)
Gas pain (for example, if the baby has not burped)
Discomfort (for example, a wet diaper)
Temperature (for example, feeling too hot or too cold)
External stimulus (for example, too much noise or light)
Boredom or loneliness
Pain (for example, teething)
Excessive crying in infants may indicate colic or another health problem. Some health problems are listed below:
Trauma
Abuse
Corneal abrasions
Foreign body in the eye
Fractured bone
Central nervous system abnormality
Chiari type I malformation
Infantile migraine
Subdural hematoma
Constipation
Cow's milk protein intolerance
Gastroesophageal reflux
Lactose intolerance
Rectal fissure
Infection
Meningitis
Otitis media
Urinary tract infection
Viral illness
Hair tourniquet syndrome
Colic
The term 'colic' was defined in 1954 as: "crying for more than three hours per day, for more than three days per week, and for more than three weeks in an infant that is well-fed and otherwise healthy." Colic and excessive crying by infants is synonymous to some clinicians. Colic is attributed to gastrointestinal discomfort like intestinal cramping. Clinicians often admit that colic cannot be treated or that alternative treatments are ineffective. The protocol followed by clinicians to treat colic is described as "treating the parents" with reassurance.
Maternal responses
Crying in infants is associated with high stress levels and depression in mothers. Excessive crying has also been linked to maternal "physical aggression" and "angry speaking." Mothers without assistance in caring for the infant, are more prone to physical aggression. During evaluations of maternal depression responses to infant crying, sleeping problems are closely associated with excessive crying. It is not always clear that when sleeping problems are associated with infant crying, whether the sleeping problems are descriptive of the mother or the infant or both. Maternal stress is associated with excessive crying.
Effects on young children
One definition used to study excessive crying in infants (colic) is crying for three or more hours per 24 hours. Excessive infant crying has been associated with a twofold increased risk of the overall problem behavior, conduct problems, hyperactivity, and mood problems at the age of 5–6. Excessive infant crying doubles the risk of behavioral, hyperactivity, and mood problems at the age of 5–6, as reported by their mother. Excessive crying is not the only factor in later childhood difficulties. Behavioral problems in childhood include the so-called regulatory problems, such as excessive crying, sleeping, and feeding problems, which occur in 20% of infants in multiproblem families. Excessive crying, whining and sleeping problems at 4–6 months are associated with decreased social development at 12 months.
Several factors may contribute to, and partly explain, an association between excessive infant crying and later behavioral and emotional problems. During early infancy, the quality of the mother–child dyad can be considered to be a crucial vehicle for child's healthy mental development. Both early maternal and early paternal reciprocity in infancy are predictive of social competence and lower aggression in preschoolers.
Compared to other infants, excessive crying infants had a slightly lower birth weight and a slightly younger gestational age. Excessive crying infants more often had a single, lower educated mother, originating from a non-industrialized country, who reported more depression, a higher burden of infant care, and more aggressive behavior and had an authoritarian parenting style. Excessive crying was associated with a higher risk for hyperactivity/inattention problems, emotional symptoms, conduct problems, peer relationship problems, and overall problem behavior at the age of 5–6, as well as a higher risk for decreased pro-social behavior as reported by the mother. Excessive crying was also associated with mood problems as well as generalized anxiety problems at the age of 5–6.
Abuse
Shaken baby syndrome
A common type of physical abuse in infants, shaken baby syndrome, is often a reaction to infant crying. Infant crying is a leading risk factor for shaken baby syndrome and other infant abuse.
References
External links
Crying it out
Bibliography
Pain scales
Pain
Pediatrics
Palliative care
Crying
Infancy
Parenting
Human development
Developmental psychology
Sleep
Wikipedia articles incorporating text from the Centers for Disease Control and Prevention
Child abuse | Infant crying | [
"Biology"
] | 1,744 | [
"Behavior",
"Developmental psychology",
"Human development",
"Behavioural sciences",
"Crying",
"Sleep",
"Human behavior"
] |
55,004,265 | https://en.wikipedia.org/wiki/Klaas%20Wynne | Klaas Wynne (also Wijnne; born 1964) is a professor in the School of Chemistry at the University of Glasgow and chair of Chemical Physics. He was previously a professor in the Department of Physics at the University of Strathclyde (1996–2010).
Education
He received his BSc in chemistry from the University of Amsterdam in 1987 and his PhD in chemistry from the University of Amsterdam in 1990 under the supervision of Joop van Voorst. He did his postdoctoral fellowship in the laboratory of Robin Hochstrasser at the University of Pennsylvania.
Research
Wynne has authored over 90 published scientific papers. His work is focused on the structure and dynamics of liquids and solutions as well as peptides, proteins, and other biomolecules treated as amorphous objects behaving much like liquids. He described the Mayonnaise Effect, which explains the anomalous increase of the viscosity of solutions with concentration in terms of a jamming transition. He is particularly interested in phase behaviour such as "supercooling of liquids, folding transitions in peptides, phase separation and nucleation using laser-tweezing, nucleation of crystals from solution", and liquid-liquid and liquid-crystalline transitions. These phenomena are studied using femtosecond spectroscopies such as ultrafast optical Kerr-effect spectroscopy, time-domain terahertz spectroscopy (THz-TDS) as well as optical microscopy and various other forms of spectroscopy.
Awards and honours
Chemical Dynamics Award of the Royal Society of Chemistry (RSC), 2018.
Associate Editor Journal of the American Chemical Society (JACS), 2017–2020.
Elected Fellow of the Royal Society of Edinburgh (FRSE), 2015.
Member of Faraday Division Council, 2013–2016.
Member of the editorial advisory board of the Journal of Physical Chemistry, 2012–2015.
Visiting professor in the Department of Chemical and Process Engineering, University of Strathclyde, 2012–2014.
Member of the board of Chemical Physics (Elsevier), 2012-
Fellow of the Royal Society of Chemistry, 2006.
Fellow of the Institute of Physics, 2005.
NATO research fellowship, 1991.
References
External links
Chemical Photonics | Wynne lab
Ultrafast Chemical Physics in the city of Glasgow
The Biomolecular spectroscopy & dynamics Cluster (BioC)
1964 births
Living people
Academics of the University of Glasgow
Fellows of the Royal Society of Edinburgh
Fellows of the Royal Society of Chemistry
Fellows of the Institute of Physics
21st-century Scottish chemists
Physical chemists
Scientists from Amsterdam
21st-century Dutch chemists
University of Amsterdam alumni | Klaas Wynne | [
"Chemistry"
] | 530 | [
"Physical chemists"
] |
55,006,885 | https://en.wikipedia.org/wiki/ROOL%20RNA%20motif | The Rumen-Originating, Ornate, Large (ROOL) RNA motif was originally discovered by bioinformatics by analyzing metagenomic sequences from cow rumen. ROOL RNAs are found in a variety of bacterial species and apparently do not code for proteins. The RNA has a complex RNA secondary structure and its average size of 581 nucleotides is unusually large for bacterial non-coding RNAs. This large size and structural complexity for a bacterial RNA is consistent with properties of large ribozymes.
ROOL RNAs are present in prophages and purified phages, but also in bacterial genomic locations that do not appear to be related to phages. ROOL RNAs are also frequently located nearby to tRNAs. The large size and complicated secondary structure of ROOL RNAs, combined with their association with tRNAs and phages are properties that are shared by the GOLLD RNA motif, another bacterial non-coding RNA. These shared properties could suggest a related function, but the commonalities could arise for other reasons.
ROOL RNAs are present in bacteria in the phyla Bacillota, Fusobacteriota and Mycoplasmatota, in addition to phages and cow rumen metagenomes, as mentioned above. Within the Bacillota, they are present in a few species of Clostridia and many lactic acid bacteria, especially those in the genus Lactobacillus.
ROOL RNAs in Lactobacillus salivarius were independently discovered based on their extremely high rates of expression in Lactobacillus salivarius UCC118 ROOL RNAs in various strains of Lactobacillus salivarius were then studied; there is a very large range in the expression levels of ROOL RNAs in different strains, and some strains do not appear to have these RNAs in their genome. ROOL RNAs in L. salivarius UC118 are so abundant in some growth conditions that in late stationary phase they exceed even 16S ribosomal RNAs. The experimentally determined size for ROOL RNAs in L. salivarius closely matches the size of the proposed RNA structure based on bioinformatics.
References
Non-coding RNA | ROOL RNA motif | [
"Chemistry"
] | 461 | [
"Biochemistry stubs",
"Molecular and cellular biology stubs"
] |
55,008,417 | https://en.wikipedia.org/wiki/Tissue%20nanotransfection | Tissue nanotransfection (TNT) is an electroporation-based technique capable of gene and drug cargo delivery or transfection at the nanoscale. Furthermore, TNT is a scaffold-less tissue engineering (TE) technique that can be considered cell-only or tissue inducing depending on cellular or tissue level applications. The transfection method makes use of nanochannels to deliver cargo to tissues topically.
History
Cargo delivery methods rely on carriers, for example nanoparticles, viral vectors, or physical approaches such as gene guns, microinjection, or electroporation. The various methods can be limited by size constraints or their ability to efficiently deliver cargo without damaging tissue. Electroporation is a physical method which harnesses an electric field to open pores in the normally semi-permeable cell membrane through which cargo can enter. In this process, the charges can be used to drive cargo in a specific direction.
Bulk electroporation (BEP) is the most conventional electroporation method. Benefits come in the form of high throughput and minimal set-up times. The downside of BEP is that the cell membrane experiences an uneven distribution of the electric field and many membranes receive irreversible damage from which they can no longer close, thus leading to low cell viability.
Attempts have been made to miniaturize electroporation such as microelectroporation (MEP) and nanochannel electroporation (NEP) which uses electroporation approached to deliver cargo through micro/nanochannels respectively. These techniques have shown to have higher efficiency of delivery, increased uniform transfection, and increased cell viability compared to BEP.
Technique
Tissue nanotransfection uses custom fabricated nanochannel arrays for nanoscale delivery of genetic cargo directly onto the surface of the skin. The postage stamp-sized chip is placed directly on the skin and an electric current is induced lasting for milliseconds to deliver the gene cargo with precise control. This approach delivers ample amounts of reprogramming factors to single-cells, creating potential for a powerful gene transfection and reprogramming method. The delivered cargo then transforms the affected cells into a desired cell type without first transforming them to stem cells. TNT is a novel technique and has been used on mice models to successfully transfect fibroblasts into neuron-like cells along with rescue of ischemia in mice models with induced vasculature and perfusion. Current methods require the fabricated TNT chip to be placed on the skin and the loading reservoir filled with a gene solution. An electrode (cathode) is placed into the well with a counter electrode (anode) placed under the chip intradermally (into the skin). The electric field generated delivers the genes.
Initial TNT experiments showed that genes could be delivered to the skin of mice. Once this was confirmed, a cocktail of gene factors (ABM) used by Vierbuchen and collaborators to reprogram fibroblast into neurons was used. Delivery of these factors demonstrated successful reprogramming in-vivo and signals propagated from the epidermis to the dermis skin layers. This phenomenon is believed to be mediated by extracellular vesicles and potentially other factors [18]. Successful reprogramming was determined by performing histology and electrophysiological tests to confirm the tissue behaved as functional neurons.
Beyond inducing neurons, Gallego-Perez et al. also set out to induce endothelial cells in an ischemic mouse limb that, without proper blood flow, becomes necrotic and decays. Using a patented cocktail of plasmids (Etv2, Fli1, Foxc2, or EFF), these factors were delivered to the tissue above the surgery site. Using various methods, including histology and laser speckle imaging, perfusion and the establishment of new vasculature was verified as early as 7 days post-treatment.
The technique was developed to combat the limitations of current approaches, such as a shortage in donors to supply cell sources and the need to induce pluripotency. Reprogramming cells in vivo takes advantage of readily available cells, bypassing the need for pre-processing. Most reprogramming methods have a heavy reliance on viral transfection. TNT allows for implementation of a non-viral approach which is able to overcome issues of capsid size, increase safety, and increase deterministic reprogramming.
Development
The tissue nanotransfection technique was developed as a method to efficiently and benignly deliver cargo to living tissues. This technique builds on the high-throughput nanoelectroporation methods developed for cell reprogramming applications by Lee and Gallego-Perez of Ohio State's Chemical and Biomolecular Engineering department. Sen (Surgery/Regenerative Medicine) adapted this technology, in collaboration with Lee in Engineering, for in vivo tissue reprogramming applications with Gallego-Perez serving the role of a shared fellow between the two programs. Development was a joint effort between OSU's College of Engineering and College of Medicine led by Gallego-Perez (Ph.D), Lee (Ph.D), and Sen (Ph.D).
This technology was fabricated using cleanroom techniques and photolithography and deep reactive ion etching (DRIE) of silicon wafers to create nanochannels with backside etching of a reservoir for loading desired factors as described in Gallego-Perez et al 2017. This chip is then connected to an electrical source capable of delivering an electrical field to drive the factors from the reservoir into the nanochannels, and onto the contacted tissue. Later, with support from Xuan, Sen developed the current version of the tissue nanotransfection chip.
References
External links
Modification of genetic information
Nanotechnology
Cellular processes | Tissue nanotransfection | [
"Materials_science",
"Biology"
] | 1,205 | [
"Modification of genetic information",
"Nanomedicine",
"Molecular genetics",
"Cellular processes",
"Nanotechnology"
] |
55,008,850 | https://en.wikipedia.org/wiki/Th%209%20cell | In cell biology, TH9 cells (T helper type 9 cells, CD4+IL-9+IL-13−IFNγ − ) are a sub-population of CD4+T cells that produce interleukin-9 (IL-9). They play a role in defense against helminth infections, in allergic responses, in autoimmunity, and tumor suppression.
Characterization
TH9 cells are characterized by their cell surface expression of CD4 and CCR6 and the lack of CCR4. Additionally, they are defined by their high secretion of interleukin‑9. Besides IL-9, TH9 cells also produce IL-10 and IL-21. However, their functions in TH9 cells are still unclear.
Differentation
Th9 cells can differentiate either from naive T lymphocytes or by a shift from TH2 cells. There are numbers of cytokines, transcription factors and other molecules, that have a role in TH9 differentiation.
Cytokines in differentiation
Cytokines play a major role in development of TH9 cells. There are many cytokines impacting differentiation of TH9 cells and their production of IL-9 but IL-4 and TGF-β are indispensable for their development and polarization.
IL-4 and TGF-β are necessary for naive T lymphocytes to differentiate into TH9 cells. while TGF-β alone can switch TH2 cells into TH9 cells.
IL-2 is critical for interleukin-9 production by TH9 cells.
IL-1 may induce IL-9 in some cases, and IL-33 is able to induce IL-9 in T cells generally. Generally IL-1 family members enhance expression of Il9 gene.
IL-25 also induces IL-9 production in vivo.
Development of TH9 cells requires a balanced cytokines signaling for its establishment. All mentioned cytokines then signal through specific transcription factors, which are later on required for a TH9 polarization.
Transcription factors in differentiation
STAT6, IRF4, GATA3 are absolutely required for TH9 cell development and other such as PU.1, BATF, NF-κB, NFAT1, STAT5, AP-1 contribute to TH9 sub-population commitment and to IL-9 production.
STAT6 is activated by signaling through IL-4 receptor. Once activated, phosphorylated STAT6 mediate the transcription of Gata3 and Irf4, which are both necessary for polarization of TH9 cells. STAT6 repress the expression of transcription factors T-bet and Foxp3 in TH9 cells, that normally block IL-9 production.
GATA-3 in TH9 cells development represses transcriptional factor FOXP3, which would other wise let to other T helper cell subpopulation.
IRF4 binds to the promoter of Il-9 gene in TH9 cells and it is dependent on STAT6.
BATF has been also shown to bind to the Il-9 gene promoter and to activate Il-9gene transcription.
PU.1 works by directly binding to the promoter of Il-9 gene and attract chromatin-modifying enzymes which reinforce Il9-gene transcription.
NF-κB and NFAT1, are needed for a TCR-induced interleukin-9 production by TH9 cells.
STAT5, downstream factor of IL-2, induce TH9 cells IL-9. STAT5 directly bind to Il-9 gene promoter, although it has not yet been determined how important this pathway is for TH9 development in vitro and in vivo.
Molecules with regulatory effects
Numbers of molecules enhance or dampen IL-9 production and contribute to TH9 development such as:
Activin A that can fully substitute the role of TGF-β in TH9 cells, then Jagged2, programmed cell death ligand (PD-L2), cyclooxy- genase (COX)-2, 1,25-dihydroxyvitamin D3, calcitonin gene-related peptide (CGRP), tumor necrosis factor receptor superfamily member 4 (TNFRSF4 or OX40), and thymic stromal lymphopoietin (TSLP).
Physiological functions
The main physiological role of TH9 cells, while poorly defined, is defense against helminthic infections. This is likely mediated by local and/or systemic production of Interleukin-9, as well as promoted survival of other anti-parasitic leukocytes, including mast cells, eosinophils and basophils.
Th9 cells have also shown both pro- and anti-tumorigenic activity, depending on the type of cancer. They have been shown to inhibit melanoma cell growth, increase anti-tumor lymphocytes, and drastically lower tumor mass and disease severity. On the other hand patients suffering hepatocellular carcinoma with high TH9 infiltration had shorter disease-free survival period after surgical resection.
Pathophysiological functions
TH9 cells appear to be linked to many pathophysiological processes. Their exact role is poorly understood, as they appear to have a pleiotropic effect and seem to be heavily dependent on the local, as well as systemic, cytokine environment.
Allergies
TH9 cells are present in the peripheral blood of allergic patients while such a population is rare in non-allergic persons. Few studies have reported distinct correlations of in vivo IL-9 with serum IgE concentration. The percentages of IL-9-secreting T cells of atopic patients also correlated with serum IgE in adults with asthma.
Two studies showed that transferred TH9 cells result in allergic inflammation in the lung. It was also observed that TH9 cells can promote intestinal and central nervous system inflammation.
Asthma
TH9 cells are strongly linked to asthma given their presence in draining lymph nodes and airways.
TH9-Derived IL-9 has been shown to exacerbate the allergic immune response by enhancing antibody production and increasing cell infiltration inside of the respiratory tract.
Autoimmune inflammation
TH9 cells contribute to ulcerative colitis, due to the cell’s ability to impair cellular repair, as well as due to the ability of secreted IL-9 to promote a TH2-like immune response. This may also play a role in TH9 tumor suppression (see "Physiological functions" above). TH9 have been shown to play a role in both early and progressive phase of multiple sclerosis by decreasing the effects of pro-inflammatory TH17. Increased levels of IL-9, mainly produced by TH9 have been detected in patients in remission phase of the disease. However, in vitro differentiated Th9 have been shown to induce EAE and cause peripheral neuropathies in mice, emphasizing the importance of context in which the cells develops and functions.
Chronic infections
A higher percentage of TH9 cells in patients with chronic HCV was linked to higher levels of liver enzymes, more severe disease progression and faster development of HCC. Also remission and faster HCV clearance was associated with lower TH9 cytokines' levels. This might be caused by TH9 mediated promotion of TH17 phenotype and hindering of TH1 phenotype which leads to persisting viral infection. There were several publications trying to elucidate role of TH9 cells in chronic HBV infection with inconsistent results.
References
Immune system
Cell biology
Immunology | Th 9 cell | [
"Biology"
] | 1,550 | [
"Immune system",
"Organ systems",
"Immunology",
"Cell biology"
] |
55,010,333 | https://en.wikipedia.org/wiki/Gabriel%20Filippelli | Gabriel Filippelli is an American biogeochemist and professor of Earth sciences at Indiana University-Purdue University Indianapolis (IUPUI). In 2017 he began serving as the Editor in Chief of GeoHealth. Filippelli is the author of two books and many journal articles. He is the recipient of several awards and served as senior science advisor for the United States State Department from 2013–2014. His research addresses biogeochemical cycling in the environment, and the links between environmental processes and human health.
Education
Filippelli was awarded a BS in geology from the University of California, Davis in 1986, a PhD in 1994 from the University of California, Santa Cruz, and then began working as an assistant professor of geology in 1994.
Career
Filippelli is a Chancellor's Professor of Earth Sciences, the executive director of the Indiana University Environmental Resilience Institute and director of the Center for Urban Health at IUPUI.
Filippelli has been a member and chair of the United States Advisory Committee for Scientific Ocean Drilling and of the Science Planning Committee for the International Ocean Discovery Program. He has also written for a variety of major journals, including Nature, Science, and Geology, among others.
Policy
Filippelli was senior science advisor for the United States State Department from 2013–2014, working in the area of ocean and polar science policy. In this capacity, he wrote policy related to climate change in the Antarctic, and was involved in the international effort to improve scientific cooperation through the Arctic nations, eventually leading to an international agreement on this issue
In 2015 he organized a letter addressed to then Indiana governor, Mike Pence, asking to be consulted for developing Indiana's climate change adaptation plans. Governor Pence did not respond.
Filippelli is an Air Quality Fellow for the US State Department and consults with embassies and universities in Pakistan on air quality science.
Research
Filippelli is known for his work on various aspects of global nutrient cycling, including evolution of the Antarctic Circumpolar Current, terrestrial signals of cycling and landscape development, and future projections of nutrient resources to feed humanity. His recent work has focused on environmental health, marked by contributions in multiple journals on environmental exposures to contaminants and climate change.
He is the author of Climate Change and Life and a co-editor of Climate Change and Resilience in Indiana and Beyond.
Academic roles
Filippelli is a 2015 Fellow of the International Association of GeoChemistry, the winner of the Charles Bantz Fellowship for Community Engagement, the author of about 100 peer-reviewed publications, a blogger, and community activist in the areas of community-engaged research and environmental justice. In August 2017, Filippelli became the Editor in Chief of GeoHealth, an American Geophysical Union journal. The journal's founding editor was Rita R. Colwell.
Awards
Fulbright Distinguished Chair (2022), University of Newcastle, Australia
F. Earl Ingerson Lecturer (2021), Geochemical Society
John W. Ryan Award for Distinguished Contributions to International Programs and Studies, Indiana University (2020)
Chancellor's Professor, IUPUI (2020)
Prose Award for Excellence in Physical Science and Mathematics, Association of American Publishers (2019)
Fellow, International Association of GeoChemistry (2015)
References
awarded a PhD in Earth Sciences
Year of birth missing (living people)
Living people
American geochemists
University of California, Davis alumni
Indiana University faculty | Gabriel Filippelli | [
"Chemistry"
] | 702 | [
"Geochemists",
"American geochemists"
] |
55,010,893 | https://en.wikipedia.org/wiki/Amauroderma%20albostipitatum | Amauroderma albostipitatum is a polypore fungus in the family Ganodermataceae. It was described as a new species in 2015 by mycologists Allyne Christina Gomes-Silva, Leif Ryvarden, and Tatiana Gibertoni. The specific epithet albostipitatum refers to the characteristic whitish stipe. A. albostipitatum is found in the states of Rondônia and Roraima, in the Brazilian Amazon. It fruits on soil.
References
albostipitatum
Fungi described in 2015
Fungi of Brazil
Taxa named by Leif Ryvarden
Fungus species | Amauroderma albostipitatum | [
"Biology"
] | 128 | [
"Fungi",
"Fungus species"
] |
55,010,912 | https://en.wikipedia.org/wiki/Amauroderma%20aurantiacum | Amauroderma aurantiacum is a polypore fungus in the family Ganodermataceae. It was first described as a species of Ganoderma by Portuguese botanist Camille Torrend in 1932. Tatiana Gibertoni and Annarosa Bernicchia transferred it to Amauroderma in 2008. A. aurantiacum is found in Brazil and Venezuela.
References
aurantiacum
Fungi described in 1932
Fungi of South America
Fungus species | Amauroderma aurantiacum | [
"Biology"
] | 92 | [
"Fungi",
"Fungus species"
] |
55,010,947 | https://en.wikipedia.org/wiki/Amauroderma%20calcigenum | Amauroderma calcigenum is a polypore fungus in the family Ganodermataceae. It was first described as a species of Polyporus by Miles Joseph Berkeley in 1843. Camille Torrend transferred it to genus Amauroderma in 1920. A. calcigenum is found in Brazil, Guyana, and Venezuela.
References
calcigenum
Fungi described in 1843
Fungi of South America
Taxa named by Miles Joseph Berkeley
Fungus species | Amauroderma calcigenum | [
"Biology"
] | 92 | [
"Fungi",
"Fungus species"
] |
55,010,957 | https://en.wikipedia.org/wiki/Amauroderma%20floriformum | Amauroderma floriformum is a polypore fungus in the family Ganodermataceae. It was described as a new species in 2015 by mycologists Allyne Christina Gomes-Silva, Leif Ryvarden, and Tatiana Gibertoni. The specific epithet floriformum (from the Latin words flos = flower and forma = shape) refers to the flower-shaped fruit body. A. floriformum is found in the state of Pará, in the Brazilian Amazon.
References
floriformum
Fungi described in 2015
Fungi of Brazil
Taxa named by Leif Ryvarden
Fungus species | Amauroderma floriformum | [
"Biology"
] | 129 | [
"Fungi",
"Fungus species"
] |
55,010,974 | https://en.wikipedia.org/wiki/Amauroderma%20laccatostiptatum | Amauroderma laccatostiptatum is a polypore fungus in the family Ganodermataceae. It was described as a new species in 2015 by mycologists Allyne Christina Gomes-Silva, Leif Ryvarden, and Tatiana Gibertoni. The specific epithet laccatostiptatum (from the Latin words laccatus = "appearing varnished" and stipitatum = "with a stipe") refers to the varnished stipe. A. laccatostiptatum is found in the states of Amazonas, Pará, and Rondônia in the Brazilian Amazon. The fungus fruits on soil.
References
laccatostiptatum
Fungi described in 2015
Fungi of Brazil
Taxa named by Leif Ryvarden
Fungus species | Amauroderma laccatostiptatum | [
"Biology"
] | 161 | [
"Fungi",
"Fungus species"
] |
55,010,998 | https://en.wikipedia.org/wiki/Amauroderma%20ovisporum | Amauroderma ovisporum is a polypore fungus in the family Ganodermataceae. It was described as a new species in 2015 by mycologists Allyne Christina Gomes-Silva, Leif Ryvarden, and Tatiana Gibertoni. The specific epithet ovisporum (from the Latin words ovi = "egg" and spora = "spore") refers to the ovoid shape of the basidiospores. A. ovisporum is found in the states of Pará and Rondônia in the Brazilian Amazon.
References
ovisporum
Fungi described in 2015
Fungi of Brazil
Taxa named by Leif Ryvarden
Fungus species | Amauroderma ovisporum | [
"Biology"
] | 143 | [
"Fungi",
"Fungus species"
] |
55,011,018 | https://en.wikipedia.org/wiki/Amauroderma%20sessile | Amauroderma sessile is a polypore fungus in the family Ganodermataceae. It was described as a new species in 2015 by mycologists Allyne Christina Gomes-Silva, Leif Ryvarden, and Tatiana Gibertoni. The specific epithet sessile (from the Latin word sessilis = without a stipe) refers to the characteristic stipe-free fruit body. A. sessile is found in the states of Amazonas, Mato Grosso, and Pará in the Brazilian Amazon.
References
sessile
Fungi described in 2015
Fungi of Brazil
Taxa named by Leif Ryvarden
Fungus species | Amauroderma sessile | [
"Biology"
] | 134 | [
"Fungi",
"Fungus species"
] |
55,011,042 | https://en.wikipedia.org/wiki/Amauroderma%20subsessile | Amauroderma subsessile is a polypore fungus in the family Ganodermataceae. It was described as a new species in 2015 by mycologists Allyne Christina Gomes-Silva, Leif Ryvarden, and Tatiana Gibertoni. The specific epithet subsessile (from the Latin words sub "somewhat" and sessilis = "without a stipe") refers to "the basidiomata not completely sessile, with a short to long stipe". A. subsessile is found in the states of Rondônia and Pará in the Brazilian Amazon, as well as Costa Rica and Panama.
References
subsessile
Fungi described in 2015
Fungi of Central America
Fungi of Brazil
Taxa named by Leif Ryvarden
Fungus species | Amauroderma subsessile | [
"Biology"
] | 164 | [
"Fungi",
"Fungus species"
] |
55,011,892 | https://en.wikipedia.org/wiki/Waves%20and%20Instabilities%20from%20a%20Neutral%20Dynamo | Waves and Instabilities from a Neutral Dynamo or WINDY is space experiment mission for the purpose to study a phenomenon that occurs in the ionosphere – a layer of charged particles in the upper atmosphere.
Mission
WINDY is a NASA rocket mission that hopes to study disturbances in the upper atmosphere that might interfere with communication and technology systems. The experiment will form night-time white artificial clouds that will be visible by residents of the Republic of the Marshall Islands during two rocket flights. The rockets were launched September 9, 2017.
References
Ionosphere
NASA programs | Waves and Instabilities from a Neutral Dynamo | [
"Astronomy"
] | 108 | [
"Outer space stubs",
"Astronomy stubs",
"Outer space"
] |
55,012,202 | https://en.wikipedia.org/wiki/Matricin | Matricin is a sesquiterpene. It can be extracted from flower of chamomille (Matricaria chamomilla). Matricin is colorless.
Chamazulene, a blue-violet derivative of azulene, found in a variety of plants including in chamomile (Matricaria chamomilla), wormwood (Artemisia absinthium) and yarrow (Achillea millefolium) is biosynthesized from matricin.
References
Sesquiterpenes
Dienes
Acetate esters
Tertiary alcohols
Anthemideae
Heterocyclic compounds with 3 rings
Oxygen heterocycles | Matricin | [
"Chemistry"
] | 145 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
55,012,592 | https://en.wikipedia.org/wiki/Christian%20Hamel | Christian Hamel (4 October 1955 – 15 August 2017) was a French Professor at the Institute for Neurosciences of Montpellier, Hôpital Saint Eloi (INM) research unit INSERM 583 of the University. He studied transduction, integration and disorders of sensory and motor systems with the ultimate goal of finding treatments for degeneration of the retina and optic nerve.
Hamel discovered and described in 1993 the RPE65 protein. Retinal pigment epithelium-specific 65 kDa protein is an enzyme in the vertebral visual pigment. The next year he mapped the RPE65 gene to human chromosome 1 (mouse chromosome 3) and refined it to 1p31 by fluorescence in situ hybridization. His research interests were to find the causes of inherited diseases of the retina and optic nerve.
References
1955 births
2017 deaths
French medical researchers
Genetic engineering
Engineering | Christian Hamel | [
"Chemistry",
"Engineering",
"Biology"
] | 182 | [
"Biological engineering",
"Genetic engineering",
"Molecular biology"
] |
55,013,035 | https://en.wikipedia.org/wiki/French%20Crystallographic%20Association | The French Crystallographic Association (L’Association française de cristallographie or AFC) brings together physicists, chemists and biologists that use crystals and crystallography in their research or develop new crystallographic methods. Originally part of the French Society of Mineralogy, the AFC was founded in 1953 by Hubert Curien and André Guinier.
Today, its main goals are to promote dissemination of knowledge and exchange between French speaking crystallographers from all fields, and in particular to organize or support specialized or interdisciplinary workshops and conferences, educational actions and training courses in the area of crystallography. During the biannual AFC conferences, the AFC awards three PhD prizes in each of its research areas: Physics, Chemistry and Biology.
Claude Sauter, scientist at the Institut de Biologie Moléculaire et Cellulaire in Strasbourg is the President of the AFC from January 1st, 2022.
Presidents of the AFC
André Guinier
Robert Gay
Jean Wyart
1962 Erwin Félix Lewy-Bertaut
1965 Hubert Curien
1970-1972 André Authier
1972-1973 Stanislas Goldstaub
1981-1983 Jean Meinnel
1984-1987 Jean-François Petroff
1987-1990 Michel Hospital
1990-1993 Massimo Marezio
1994-1997 Roger Fourme
1997-2002 Claude Lecomte
2003-2007 Jean-Louis Hodeau
2008-2010 Jean-Claude Daran
2011-2013 Jacqueline Cherfils
2013-2016 René Guinebretière
2017-2021 Philippe Guionneau
2022-2025 Claude Sauter
See also
International Union of Crystallography
European Crystallographic Association
References
External links
Website of the French Crystallographic Association
Crystallography organizations
Scientific organizations established in 1953
Scientific organizations based in France
1953 establishments in France
Chemistry societies | French Crystallographic Association | [
"Chemistry",
"Materials_science"
] | 359 | [
"Materials science stubs",
"Chemistry organization stubs",
"Crystallography stubs",
"Crystallography",
"nan",
"Chemistry societies",
"Crystallography organizations"
] |
55,013,132 | https://en.wikipedia.org/wiki/Safety%20of%20magnetic%20resonance%20imaging | Magnetic resonance imaging (MRI) is in general a safe technique, although injuries may occur as a result of failed safety procedures or human error. During the last 150 years, thousands of papers focusing on the effects or side effects of magnetic or radiofrequency fields have been published. They can be categorized as incidental and physiological. Contraindications to MRI include most cochlear implants and cardiac pacemakers, shrapnel and metallic foreign bodies in the eyes. The safety of MRI during the first trimester of pregnancy is uncertain, but it may be preferable to other options. Since MRI does not use any ionizing radiation, its use generally is favored in preference to CT when either modality could yield the same information. (In certain cases, MRI is not preferred as it may be more expensive, time-consuming and claustrophobia-exacerbating.)
Structure and certification
In an effort to standardize the roles and responsibilities of MRI professionals, an international consensus document, written and endorsed by major MRI and medical physics professional societies from around the globe, has been published formally. The document outlines specific responsibilities for the following positions:
MR Medical Director / Research Director (MRMD) – This individual is the supervising physician who has oversight responsibility for the safe use of MRI services.
MR Safety Officer (MRSO) – Roughly analogous to a radiation safety officer, the MRSO acts on behalf of, and on the instruction of, the MRMD to execute safety procedures and practices at the point of care.
MR Safety Expert (MRSE) – This individual serves in a consulting role to both the MRMD and MRSO, assisting in the investigation of safety questions that may include the need for extrapolation, interpolation, or quantification to approximate the risk of a specific study.
The American Board of Magnetic Resonance Safety (ABMRS) provides testing and board certification for each of the three positions, MRMD, MRSO, and MRSE. As most MRI accidents and injuries are directly attributable to decisions at the point of care, testing and certification of MRI professionals seeks to reduce the rates of MRI accidents and improve patient safety through the establishment of safety competency levels for MRI professionals.
Implants
All patients are reviewed for contraindications prior to MRI scanning. Medical devices and implants are categorized as MR Safe, MR Conditional or MR Unsafe:
MR-Safe – The device or implant is completely non-magnetic, non-electrically conductive, and non-RF reactive, eliminating all of the primary potential threats during an MRI procedure.
MR-Conditional – A device or implant that may contain magnetic, electrically conductive, or RF-reactive components that is safe for operations in proximity to the MRI, provided the conditions for safe operation are defined and observed (such as 'tested safe to 1.5 teslas' or 'safe in magnetic fields below 500 gauss in strength').
MR-Unsafe – Objects that are significantly ferromagnetic and pose a clear and direct threat to persons and equipment within the magnet room.
The MRI environment may cause harm in patients with MR-Unsafe devices such as cochlear implants, aneurysm clips, and many permanent pacemakers. In November 1992, a patient with an undisclosed cerebral aneurysm clip was reported to have died shortly after an MRI exam. Several deaths have been reported in patients with pacemakers who have undergone MRI scanning without appropriate precautions. Increasingly, MR-conditional pacemakers are available for selected patients.
Ferromagnetic foreign bodies such as shell fragments, or metallic implants such as surgical prostheses and ferromagnetic aneurysm clips also are potential risks. Interaction of the magnetic and radio frequency fields with such objects may lead to heating or torque of the object during an MRI. MRI is contraindicated in those suspected with metallic foreign body in the eye. MRI may be considered if there is strong suspicion of non-metallic foreign body.
Titanium and its alloys are safe from attraction and torque forces produced by the magnetic field, although there may be some risks associated with Lenz effect forces acting on titanium implants in sensitive areas within the subject, such as stapes implants in the inner ear.
Intrauterine devices with copper are generally safe in MRI, but may become dislodged or even expelled, and it is therefore recommended to check the location of the IUD both before and after MRI.
Other implants that are contraindicated in MRI includes: magnetic dental implants, tissue expander, artificial limb, hearing aid, catheters with metallic components such as Swan-Ganz catheter and piercing. However, tooth amalgam is not contraindicated in MRI.
Risk of implant heating under MRI
Titanium and its alloys can heat from the radiofrequency field, as well as the switched gradient field (due to Faraday's law of magnetic induction).
The amount of heating that takes place has a number of contributing factors:
Injuries have been reported by this heating of metallic implants:
Projectile risk
The very high strength of the magnetic field may cause projectile effect (or "missile-effect") accidents, where ferromagnetic objects are attracted to the center of the magnet. Pennsylvania reported 27 cases of objects becoming projectiles in the MRI environment between 2004 and 2008. There have been incidents of injury and death. In one case, a six-year-old boy died in July 2001, during an MRI exam at the Westchester Medical Center, New York, after a metal oxygen tank was pulled across the room and crushed the child's head. To reduce the risk of projectile accidents, ferromagnetic objects and devices are typically prohibited near the MRI scanner, and patients undergoing MRI examinations must remove all metallic objects, often by changing into a gown or scrubs. Some radiology departments use ferromagnetic detection devices to ensure that no ferromagnetic objects enter the scanner room.
MRI-EEG
In research settings, structural MRI or functional MRI (fMRI) may be combined with EEG (electroencephalography) under the condition that the EEG equipment is MR-compatible. Although EEG equipment (electrodes, amplifiers, and peripherals) are either approved for research or clinical use, the same MR Safe, MR Conditional and MR Unsafe terminology applies. With the growth of the use of MR technology, the U.S. Food & Drug Administration [FDA] recognized the need for a consensus on standards of practice, and the FDA sought out ASTM International [ASTM] to achieve them. Committee F04 of ASTM developed F2503, Standard Practice for Marking Medical Devices and Other Items for Safety in the Magnetic Resonance Environment.
Genotoxic effects
There is no proven risk of biological harm from any aspect of an MRI scan, including very powerful static magnetic fields, gradient magnetic fields, or radio frequency waves. Some studies have suggested possible genotoxic (i.e., potentially carcinogenic) effects of MRI scanning through micronuclei induction and DNA double strand breaks in vivo and in vitro, however, in most, if not all cases, others have been unable to repeat or validate the results of these studies, and the majority of research shows no genotoxic, or otherwise harmful, effects caused by any part of MRI. A recent study confirmed that MRI using some of the most potentially-risky parameters tested to date (7-tesla static magnetic field, 70 mT/m gradient magnetic field, and maximum strength radio frequency waves) did not cause any DNA damage in vitro.
Peripheral nerve stimulation
The rapid switching on and off of the magnetic field gradients is capable of causing nerve stimulation. Volunteers report a twitching sensation when exposed to rapidly switched fields, particularly in their extremities. The reason the peripheral nerves are stimulated is that the changing field increases with distance from the center of the gradient coils (which more or less coincides with the center of the magnet). Although PNS was not a problem for the slow, weak gradients used in the early days of MRI, the strong, rapidly switched gradients used in techniques such as EPI, fMRI, diffusion MRI, etc. are capable of inducing PNS. American and European regulatory agencies insist that manufacturers stay below specified dB/dt limits (dB/dt is the change in magnetic field strength per unit time), or else prove that no PNS is induced for any imaging sequence. As a result of dB/dt limitation, commercial MRI systems cannot use the full rated power of their gradient amplifiers.
Heating caused by absorption of radio waves
Every MRI scanner has a powerful radio transmitter that generates the electromagnetic field that excites the spins. If the body absorbs the energy, heating occurs. For this reason, the transmitter rate at which energy is absorbed by the body must be limited (see Specific absorption rate). It has been claimed that tattoos made with iron-containing dyes may lead to burns on the subject's body. Cosmetics are very unlikely to undergo heating, as well as body lotions, since the outcome of the reactions between those with the radio waves is unknown. The best option for clothing is 100% cotton.
There are several positions strictly forbidden during measurement such as crossing arms and legs, and the patient's body may not create loops of any kind for the RF during the measurement.
Acoustic noise
Switching of field gradients causes a change in the Lorentz force experienced by the gradient coils, producing minute expansions and contractions of the coil. As the switching typically is in the audible frequency range, the resulting vibration produces loud noises (clicking, banging or beeping). This behaviour, of sound being generated by the vibration of the conducting components, is described as a coupled acousto-magneto-mechanical system, solutions to which provide useful insight to the behaviour of the scanners. This is most marked with high-field machines, and rapid-imaging techniques in which sound pressure levels may reach 120 dB(A) (equivalent to a jet engine at take-off), and therefore, appropriate ear protection is essential for anyone inside the MRI scanner room during the examination.
Radio frequency in itself does not cause audible noises (at least for human beings), since modern systems are using frequencies of 8.5 MHz (0.2 T system) or higher.
Cryogens
As described in the Physics of magnetic resonance imaging article, many MRI scanners rely on cryogenic liquids to enable the superconducting capabilities of the electromagnetic coils within. Although the cryogenic liquids used are non-toxic, their physical properties present specific hazards.
An unintentional shut-down of a superconducting electromagnet, an event known as "quench", involves the rapid boiling of liquid helium from the device. If the rapidly expanding helium cannot be dissipated through an external vent, sometimes referred to as a 'quench pipe', it may be released into the scanner room where it may cause displacement of the oxygen and present a risk of asphyxiation.
Oxygen deficiency monitors usually are used as a safety precaution. Liquid helium, the most commonly used cryogen in MRI, undergoes near explosive expansion as it changes from a liquid to gaseous state. The use of an oxygen monitor is important to ensure that oxygen levels are safe for patients and physicians. Rooms built for superconducting MRI equipment should be equipped with pressure relief mechanisms and an exhaust fan, in addition to the required quench pipe.
Because a quench results in rapid loss of cryogens from the magnet, recommissioning the magnet is expensive and time-consuming. Spontaneous quenches are uncommon, but a quench also may be triggered by an equipment malfunction, an improper cryogen fill technique, contaminants inside the cryostat, or extreme magnetic or vibrational disturbances.
Pregnancy
No effects of MRI on the fetus have been demonstrated. As opposed to many other forms of medical imaging in pregnancy, MRI avoids the use of ionizing radiation, to which the fetus is particularly sensitive. As a precaution, however, many guidelines recommend pregnant women only undergo MRI when essential, especially during the first trimester.
The concerns in pregnancy are the same as for MRI in general, but the fetus may be more sensitive to the effects—particularly to heating and to noise. The use of gadolinium-based contrast media in pregnancy is an off-label indication and may be administered only in the lowest dose required to provide essential diagnostic information.
Despite these concerns, MRI is rapidly growing in importance as a way of diagnosing and monitoring congenital defects of the fetus because it is able to provide more diagnostic information than ultrasound and it lacks the ionizing radiation of CT. MRI without contrast agents is the imaging mode of choice for pre-surgical, in-utero diagnosis and evaluation of fetal tumors, primarily teratomas, facilitating open fetal surgery, other fetal interventions, and planning for procedures (such as the EXIT procedure) to safely deliver and treat babies whose defects would otherwise be fatal.
Claustrophobia and discomfort
Although painless, MRI scans may be unpleasant for those who are claustrophobic or otherwise uncomfortable with the imaging device surrounding them. Older closed bore MRI systems have a fairly long tube or tunnel. The part of the body being imaged must lie at the center of the magnet, which is at the absolute center of the tunnel. Because scan times on these older scanners may be long (occasionally up to 40 minutes for the entire procedure), people with even mild claustrophobia are sometimes unable to tolerate an MRI scan without management. Some modern scanners have larger bores (up to 70 cm) and scan times are shorter. A 1.5 T wide short bore scanner increases the examination success rate in patients with claustrophobia and substantially reduces the need for anesthesia-assisted MRI examinations even when claustrophobia is severe.
Alternative scanner designs, such as open or upright systems, may be helpful where these are available. Although open scanners have increased in popularity, they produce inferior scan quality because they operate at lower magnetic fields than closed scanners. Commercial 1.5-tesla open systems have become available recently, however, providing much better image quality than previous lower field strength open models.
Mirror glasses may be used to help create the illusion of openness. The mirrors are angled at 45 degrees, allowing the patient to look down their body and out the end of the imaging area. The appearance is of an open tube pointing upward (as seen when lying in the imaging area). Even though one is able to see around the glasses and the proximity of the device is very evident, this illusion is quite persuasive and relieves the claustrophobic feeling.
For young children who cannot hold still or would be frightened during the examination, chemical sedation or general anesthesia are the norm. Some hospitals encourage children to pretend the MRI machine is a spaceship or other adventure. Certain hospitals with Children's wards have decorated scanners for this purpose, such as that at the Boston Children's Hospital, which operates a scanner with a special casing designed to resemble a sandcastle.
Obese patients and pregnant women may find the MRI machine a tight fit. Pregnant women in the third trimester also may have difficulty lying on their backs for an hour or more without moving.
MRI versus CT
MRI and computed tomography (CT) are complementary imaging technologies and each has advantages and limitations for particular applications. CT is more widely used than MRI in OECD countries with a mean of 132 vs. 46 exams per 1000 population performed respectively. A concern is the potential for CT to contribute to radiation-induced cancer and in 2007 it was estimated that 0.4% of current cancers in the United States were due to CTs performed in the past, and that in the future this figure may rise to 1.5–2% based on historical rates of CT usage. An Australian study found that one in every 1800 CT scans was associated with an excess cancer. An advantage of MRI is that no ionizing radiation is used and so it is recommended over CT when either approach could yield the same diagnostic information. Although the cost of MRI has fallen, making it more competitive with CT, there are not many common imaging scenarios in which MRI can simply replace CT, however, this substitution has been suggested for the imaging of liver disease. The effect of low doses of radiation on carcinogenesis also are disputed. Although MRI is associated with biological effects, these have not been proven to cause measurable harm.
Iodinated contrast medium is routinely used in CT and the main adverse events are anaphylactoid reactions and nephrotoxicity. Commonly used MRI contrast agents have a good safety profile, but linear non-ionic agents in particular have been implicated in nephrogenic systemic fibrosis in patients with severely impaired renal function.
MRI is contraindicated in the presence of MR-unsafe implants, and although these patients may be imaged with CT, beam hardening artefact from metallic devices, such as pacemakers and implantable cardioverter-defibrillators, also may affect image quality. MRI is a longer investigation than CT and an exam may take between 20 and 40 minutes depending on complexity.
Guidance
Safety issues, including the potential for biostimulation device interference, movement of ferromagnetic bodies, and incidental localized heating, have been addressed in the American College of Radiology's White Paper on MR Safety, which originally was published in 2002 and expanded in 2004. The ACR White Paper on MR Safety has been rewritten and was released early in 2007 under the new title ACR Guidance Document for Safe MR Practices.
In December 2007, the Medicines and Healthcare products Regulatory Agency (MHRA), a UK healthcare regulatory body, issued their Safety Guidelines for Magnetic Resonance Imaging Equipment in Clinical Use. In February 2008, the Joint Commission, a U.S. healthcare accrediting organization, issued a Sentinel Event Alert #38, their highest patient safety advisory, on MRI safety issues. In July 2008, the United States Veterans Administration, a federal governmental agency serving the healthcare needs of former military personnel, issued a substantial revision to their MRI Design Guide, that includes physical and facility safety considerations.
The European Directive on electromagnetic fields
This Directive (2013/35/EU – electromagnetic fields)
covers all known direct biophysical effects and indirect effects caused by electromagnetic fields within the EU and repealed the 2004/40/EC directive. The deadline for implementation of the new directive was 1 July 2016. Article 10 of the directive sets out the scope of the derogation for MRI, stating that the exposure limits may be exceeded during "the installation, testing, use, development, maintenance of or research related to magnetic resonance imaging (MRI) equipment for patients in the health sector, provided that certain conditions are met." Uncertainties remain regarding the scope and conditions of this derogation.
References
History of medical imaging
Magnetic resonance imaging
Magnetic resonance imaging | Safety of magnetic resonance imaging | [
"Chemistry"
] | 3,875 | [
"Nuclear magnetic resonance",
"Magnetic resonance imaging"
] |
55,013,962 | https://en.wikipedia.org/wiki/Normaliz | Normaliz is a free computer algebra system developed by Winfried Bruns, Robert Koch (1998–2002), Bogdam Ichim (2007/08) and Christof Soeger (2009–2016). It is published under the GNU General Public License version 2.
Normaliz computes lattice points in rational polyhedra, or, in other terms, solves linear diophantine systems of equations, inequalities, and congruences. Special tasks are the computation of lattice points in bounded rational polytopes and Hilbert bases of rational cones. Normaliz also computes enumerative data, such as multiplicities (volumes) and Hilbert series. The kernel of Normaliz is a templated C++ class library. For multivariate polynomial arithmetic it uses CoCoALib.
Normaliz has interfaces to several general computer algebra systems: CoCoA, GAP, Macaulay2 and Singular. It can be used interactively via its Python interface PyNormaliz. Its use in SageMath is in preparation.
Jesús A. De_Loera cites Normaliz among his favorite programs for computing Hilbert basis.
See also
Comparison of computer algebra systems
References
External links
Publications and examples of Normaliz applications
http://github.com/normaliz/Normaliz
Computer algebra system software for Linux
Computer algebra system software for macOS
Computer algebra system software for Windows
Cross-platform free software
Free computer algebra systems
Computer algebra systems | Normaliz | [
"Mathematics"
] | 298 | [
"Computer algebra systems",
"Mathematical software"
] |
55,014,116 | https://en.wikipedia.org/wiki/Artesonado | Artesonado or Spanish ceiling is a term for "a type of intricately joined wooden ceiling in which supplementary laths are interlaced into the rafters supporting the roof to form decorative geometric patterns", found in Spanish architecture. It is an example of Mudéjar style.
Artesonado decoration is usually in regular recesses between the rafter beams and the woodwork is gilded or painted. It originated in the Islamic regions of North Africa and Al-Andalus, as can be seen at the Nasrid palace of the Alhambra, and was introduced into the Iberian Christian kingdoms by Muslim craftsmen during the Christian reconquest of the Iberian Peninsula. The name comes from the Spanish word artesa, a shallow basin used in bread making.
Beginning in the 13th century, artesonado ceilings continued to be built through the Spanish Renaissance in the 15th and 16th centuries, with a change of the motifs to a classical Greco-Roman style.
Notable examples of artesonado ceilings include those in the throne room of the Aljafería (Zaragoza), the Chapterhouse of Toledo Cathedral, and the Royal Convent of Santa Clara (Tordesillas). The Spanish National Sculpture Museum also has a Spanish ceiling collection.
Original artesonado ceilings, although expensive to transport and difficult to reassemble, were bought by private collectors during the 20th century and can be currently found, for example, in the Hearst Castle, Metropolitan Museum of New York, Fine Arts Museum of San Francisco, Tomas Aquinas College of Ventura County, Worcester Art Museum and Instituto Helenístico de Ciudad de México.
Gallery
References
External links
Architecture in Spain
Ceilings
Mudéjar architecture
Islamic architectural elements | Artesonado | [
"Engineering"
] | 339 | [
"Structural engineering",
"Ceilings"
] |
56,467,603 | https://en.wikipedia.org/wiki/Durai%20Sundar | Durai Sundar is an Indian computational biologist, bioinformatician and the current Head of the Department of Biochemical Engineering and Biotechnology at the Indian Institute of Technology, Delhi. He is known for his studies in the fields of genome editing tool designing, biological studies of natural drugs and metabolic engineering as well as for his participation in the Indo-Japanese collaborative research initiatives on anti-cancer drug development and is a life member of the National Academy of Sciences, India.
The Department of Biotechnology of the Government of India awarded him the National Bioscience Award for Career Development, one of the highest Indian science awards, for his contributions to biosciences, in 2012.
Biography
Durai Sundar, born in the south Indian state of Pondicherry, did his undergraduate and post-graduate studies as well as his doctoral studies at Pondicherry University and completed his post-doctoral work at Johns Hopkins University. Subsequently, he joined the Indian Institute of Technology, Delhi (IITD) as a member of faculty where he is an associate professor, holding the Dupont Young Professor chair. At IITD, he chairs Tryst, IIT Delhi and serves as an associate faculty at the School of Interdisciplinary Research and the Value Education Centre (NRCVEE). He also coordinates the Bioinformatics Centre, a project funded by the Department of Biotechnology and DaiLab, a collaborative biomedical initiative between IIT Delhi and the National Institute of Advanced Industrial Science and Technology (AIST, Japan).
Professional profile
Sundar is known to have carried out research in the fields of genome editing tool designing, biological studies of natural drugs and metabolic engineering. When DaiLab was established at IIT Delhi, he became the coordinator of the initiative. He was a part of the team which studied the anti-cancer properties of Withania somnifera, commonly known as Ashwagandha, and the team identified Withanolide, Withaferin A and Withanone as the three steroidal contents of the plant which gives the property to it; they published their findings by way of an article published in Cell Death and Disease journal in 2017. His studies have been documented by way of a number of articles and ResearchGate, an online repository of scientific articles has listed 80 of them. Besides, he has contributed chapters to books published by others. He has also delivered invited speeches at international seminars and conferences which included the DAILAB PIKNIKH SERIES V seminar held at Tsukuba, Japan in 2015.
Awards and honors
Sundar received the Swarna Jayanti Award of the National Academy of Sciences, India in 2005 and three honors in 2006, the Young Scientist Award and the Innovative Young Biotechnologist Award of the Department of Science and Technology as well as the Young Scientist Award of the Indian Science Congress Association. The Indian National Science Academy awarded him the INSA Medal for Young Scientists in 2008 and the Lady Tata Memorial Trust selected him for the Young Researcher Award in 2011; the same year as he was elected as a life member of the National Academy of Sciences, India. The Department of Biotechnology (DBT) of the Government of India awarded him the National Bioscience Award for Career Development, one of the highest Indian science awards in 2012. He received two more awards in 2013, the Young Scientist Award of the Asian Biophysics Association and the Prof. Umakant Sinha Memorial Award of the Indian Science Congress Association.
Selected bibliography
Chapters
Articles
See also
DNA-binding domain
Acetylcholinesterase
Notes
References
External links
N-BIOS Prize recipients
Living people
Indian medical researchers
Year of birth missing (living people)
Scientists from Puducherry
Indian bioinformaticians
Pondicherry University alumni
Academic staff of IIT Delhi
Computational biology
Johns Hopkins University alumni | Durai Sundar | [
"Biology"
] | 760 | [
"Computational biology"
] |
56,467,907 | https://en.wikipedia.org/wiki/Lists%20of%20science%20and%20technology%20awards | This is a list of notable awards for specific areas of science and technology. Typically these lists give the country of the sponsoring organization, the award name, sponsor name and a description of the award criteria. Some of the awards have broad scope, or cover the intersection of different disciplines, so an award may appear in more than one list. A list of general awards for science and technology is followed by the lists of more specific awards.
General list
List of general science and technology awards
Specific lists
List of agriculture awards
List of archaeology awards
List of astronomy awards
List of aviation awards
List of biochemistry awards
List of biology awards
List of biomedical science awards
List of chemistry awards
List of computer science awards
List of computer-related awards
List of earth sciences awards
List of economics awards
List of engineering awards
List of environmental awards
List of geography awards
List of geology awards
List of geophysics awards
List of mathematics awards
List of mechanical engineering awards
List of medicine awards
List of meteorology awards
List of motor vehicle awards
List of oceanography awards
List of ornithology awards
List of paleontology awards
List of physics awards
List of psychology awards
List of science and technology awards for women
List of social sciences awards
List of space technology awards
List of student science award programs
Research
In July 2020 scientists reported that work honored by Nobel Prizes clusters in only a few scientific fields with only 36/71 having received at least one Nobel Prize of the 114/849 domains science could be divided into according to their DC2 and DC3 classification systems. Five of the 114 domains were shown to make up over half of the Nobel Prizes awarded 1995–2017 (particle physics [14%], cell biology [12.1%], atomic physics [10.9%], neuroscience [10.1%], molecular chemistry [5.3%]).
See also
Lists of awards
List of years in science
List of science communication awards
References | Lists of science and technology awards | [
"Technology"
] | 380 | [
"Science and technology awards",
"Lists of science and technology awards"
] |
56,469,937 | https://en.wikipedia.org/wiki/NGC%20522 | NGC 522, also occasionally referred to as PGC 5218 or UGC 970, is a spiral galaxy located approximately 122 million light-years from the Solar System in the constellation Pisces. It was discovered on 25 September 1862 by astronomer Heinrich Louis d'Arrest.
Observation history
D'Arrest discovered NGC 522 using his 11-inch refractor telescope at Copenhagen. He located the galaxy's position with a total of two observations. As the position matches both UGC 962 and PGC 5190, the objects are generally referred to as synonymous. NGC 522 was later catalogued by John Louis Emil Dreyer in the New General Catalogue, where the galaxy was described as "extremely faint, pretty large, irregular figure, perhaps cluster plus nebula".
Description
The galaxy can be observed edge-on from Earth, thus appearing very elongated. It can be classified as spiral galaxy of type Sbc using the Hubble Sequence. The object's distance of roughly 120 million light-years from the Solar System can be estimated using its redshift and Hubble's law.
See also
Spiral galaxy
List of NGC objects (1–1000)
Pisces (constellation)
References
External links
SEDS
Spiral galaxies
Pisces (constellation)
0522
5218
00970
Astronomical objects discovered in 1862
Discoveries by Heinrich Louis d'Arrest | NGC 522 | [
"Astronomy"
] | 274 | [
"Pisces (constellation)",
"Constellations"
] |
56,470,018 | https://en.wikipedia.org/wiki/Cognitive%20Behaviour%20Therapy%20%28journal%29 | Cognitive Behaviour Therapy is a quarterly peer-reviewed medical journal covering the application of cognitive science to the psychological study of behavior therapy. It was established in 1972 as the Scandinavian Journal of Behaviour Therapy, obtaining its current name in 2002. It is published by Taylor & Francis on behalf of the Swedish Association of Behavioural Therapists, of which it is the official journal. The editor-in-chief of the European office is Per Carlbring (Stockholm University) and that of the North American office is Mark Powers (University of Texas at Austin). In 2019 the journal had an impact factor of 4.41.
References
External links
Clinical psychology journals
Cognitive science journals
Psychotherapy journals
Behavior therapy
Academic journals established in 1972
Quarterly journals
English-language journals
Taylor & Francis academic journals | Cognitive Behaviour Therapy (journal) | [
"Biology"
] | 154 | [
"Behavior",
"Behavior therapy",
"Behaviorism"
] |
56,470,333 | https://en.wikipedia.org/wiki/Evolution%20of%20seed%20size | The first seeded plants emerged in the late Devonian 370 million years ago. Selection pressures shaping seed size stem from physical and biological sources including drought, predation, seedling-seedling competition, optimal dormancy depth, and dispersal.
History
Since the evolution of the first seeded plants ~370 million years ago, the largest change in seed size was found to be at the divergence of gymnosperms and angiosperms ~325 million years ago, but overall, the divergence of seed size appears to take place relatively consistently through evolutionary time. Seed mass has been found to be phylogenetically conservative with most differences in mean seed mass within types of seed dispersal (dispersal modes) being phylogenetic. This type of information gives us clues about how seed size evolved. Dating fossilized seeds of various sizes and comparing them with the presence of possible animal dispersers and the environmental conditions of the time is another technique used to study the evolution of seed size. Environmental conditions appear to have had a larger influence on the evolution of seed size compared to the presence of animal dispersers. One example of seed size evolving to environmental conditions is thought to have been abundant, closed forest vegetation selecting for larger seed sizes during the Eocene epoch. A general increase or decrease in seed size through time has not been found, but instead a fluctuation in seed size following the environmental conditions of the Maastrichtian, Paleocene, Eocene, Oligocene, Miocene, and Pliocene epochs. Today we also see a pattern with seed size distribution and global environmental conditions where the largest mean seed size is found in tropical forests and a steep decrease in seed size takes places globally as vegetation type changes to non-forest.
Mechanism
Modern seed sizes range from 0.0001 mg in orchid seeds to in double coconuts. Larger seeds have larger quantities of metabolic reserves in their embryo and endosperm available for the seedling than smaller seeds, and often aid establishment under low resource availability. However, smaller seeds can be produced in larger quantities which has the potential to produce more offspring and have better chances of some of the seeds dispersing into suitable habitat. This seed size-number trade off has led to the evolution of a wide range in size and number of seeds in response to environmental selection pressures.
Selective pressures
No single event, such as a large divergence in the phylogeny of seeded plants, is seen as the cause of major divergences in seed size. Rather, small events are thought to occur fairly consistently through time with minor evolutionary influence.
Shade
Species growing in shaded environments tend to produce larger seeds and larger seeded species have higher seedling survivorship in low-light conditions. The increased metabolic reserves of larger seeds allows the first shoots to grow taller and leaves to grow broader more quickly in order to compete for what little sunlight is available. A few large seeded trees that occur in closed canopy wooded areas such as old-growth forests are the many oak species, hickory, pecan, and butternut trees.
Drought
Small seeds are seen to be predominant in arid, desert environments. In some desert systems the vast majority of annual seeds weigh between zero and two milligrams. small seed size may be a favorable adaptation in desert plants for a couple reasons. Small seeds have been found to have the ability to store in dry environments for several years without desiccating. Also, in many cases, deserts have rainy seasons that provide opportunity for small seeds to germinate under conditions with ample external resources available. Due to the great importance that seeds germinate when water is available, seeds often sense the presence of water and use it as a cue to germinate. Also, many desert plants have evolved the ability to produce a fraction of their seeds to not germinate at the same time as the rest of the plant's seeds as a safe guard known as bet hedging in which if the majority of a plant's seeds germinate at one time and then die due to rain followed by drought, the potential for the plant to have successful offspring is not completely lost.
Predation
Granivors (those that feed on seeds and grains) can selectively eat either smaller or larger seeds, favoring seeds on the opposite side of the spectrum. Commonly, granivorous predation by rodents, which selectively feed on larger seeds, leads to higher fitness of smaller seeds (e.g. kangaroo rats in desert systems selectively forage on the larger seeds in the seed bank. Similarly, sometimes smaller seeds are selectively preyed upon such as with Australian granivorous ants which are only capable of carrying smaller seeds.
Seedling-seedling competition
Competition between seedlings for limited resources can result selective pressures on seed size. In dense mats of competing seedlings, those from larger seeds have higher survivorship due to their ability to more quickly grow taller shoots, broader leaves, and thus out-compete smaller seeded seedlings for resources. Germinated seedlings from larger seeds could also possibly outlive the smaller seeded seedlings which cannot live as long off their stored energy reserves.
Optimal dormancy depth
If there is a selective pressure favoring the survival of seeds buried deeper in the soil, larger seed size may evolve because of their larger reserves of energy required to emerge from further depths. One such pressure causing this type of selection is the recurrence of fires (e.g. in prairies the heat from a fire can damage or kill seeds near the surface of the soil but leave seeds buried deeper unharmed).
Dispersal
The smaller the seed, the further they can disperse, which can be beneficial for avoiding competition with siblings and the parent as well as having better chances of some of the seeds dispersing into suitable habitat. Dispersal may also lead to greater fitness in future generations if further dispersed individuals are more likely to cross pollinate with an unrelated individuals, leading to greater genetic variation. The type of seed dispersal evolved has been highly correlated to seed size in floras across the world. In general, seeds smaller than 0.1 mg are often unassisted (wind dispersed), seeds larger than 100 mg are often dispersed by vertebrates or by water, and seeds between 0.1 and 100 mg are dispersed by a large variety of dispersal modes including dispersal by a great variety of animals.
References
Evolution of plants
Phylogenetics
Tree of life (biology) | Evolution of seed size | [
"Biology"
] | 1,286 | [
"Tree of life (biology)",
"Plants",
"Taxonomy (biology)",
"Bioinformatics",
"Phylogenetics",
"Evolution of plants"
] |
56,470,344 | https://en.wikipedia.org/wiki/Monocotyledon%20reproduction | The monocots (or monocotyledons) are one of the two major groups of flowering plants (or Angiosperms), the other being the dicots (or dicotyledons). In order to reproduce they utilize various strategies such as employing forms of asexual reproduction, restricting which individuals they are sexually compatible with, or influencing how they are pollinated. Nearly all reproductive strategies that evolved in the dicots have independently evolved in monocots as well. Despite these similarities and their close relatedness, monocots and dicots have distinct traits in their reproductive biologies.
Most monocots reproduce sexually through use of seeds that have a single cotyledon, however a great number of monocots reproduce asexually through clonal propagation. Breeding systems that utilize self-incompatibility are much more common than those that utilize self-compatibility. The majority of monocots are animal pollinated (zoophilous), of which most are pollinator generalists. Monocots have mechanisms to promote or suppress cross-fertilization (allogamy) and self-fertilization (autogamy or geitonogamy). The pollination syndromes of monocots can be quite distinct; they include having flower parts in multiples of three, adaptations to pollination by water (hydrogamy), and pollination by sexual deception in orchids.
Methods of reproduction
Seed production
Reproducing through seeds is the most widespread method of reproduction in both monocots and dicots. However, internal seed structure is vastly different between these groups. The cotyledon is the embryonic leaf within a seed; monocots have one whereas dicots have two. The evolution of having one or two cotyledons may have arisen 200-150 Mya when monocots and dicots are thought to have diverged. Furthermore, the cotyledons in dicot seeds contain the endosperm which acts as the seed’s food storage, while in monocot the endosperm is separated from the cotyledon. Reproduction through seeds is normally a sexual mode of reproduction, however in some cases individuals can asexually produce fertile seeds without pollination, termed apomixis.
Clonal propagation
Some monocots can reproduce asexually without the need for seeds. Clonal propagation is the production or division of vegetative structures which develop into new individuals that are genetically identical to their progenitor. These vegetative structures can also form enlarged tubers that function as food storage. Monocots constitute the majority of plants with such structures, mainly in the families: Iridaceae, Liliaceae and Amaryllidaceae. There are many different types of clonal propagation, which are classified by the type of tissue propagating.
Rhizomes are root-like stems which usually grow laterally underground or on the ground and sprout new individuals. Most plants that produce rhizomes are monocots (grasses, bamboo, ginger, galangal, turmeric, orchids, irises, lotus); these include the families: Poaceae, Zingiberaceae, Orchidaceae, Iridaceae, and Nelumbonaceae.
Stolons (runners) are modified side-branches in which the first internode is extremely elongated and carries a new plantlet, as found in the common houseplant Chlorophytum. They can be found in grasses, irises, and orchids; these include the families: Poaceae, Iridaceae, and Orchidaceae.
Bulbs are underground food storage structures made from leaves which cycle through periods of vegetative and reproductive growth. Nearly all bulb producing plants are monocots (onion, lily, tulip, hyacinth, irises); these include the families: Amaryllidaceae, Liliaceae, Asparagaceae, and Iridaceae.
Corms are underground swollen stems that act as food storage; they appear similar to bulbs but are not layered with leaves. New corms will bud around the base of the stem. Corms can be found in irises, taro, arrowheads, sedges, and bananas; these include: Iridaceae, Araceae, Alismataceae, Asparagaceae, Colchicaceae, Cyperaceae, and Musaceae.
Keikis are clonal individuals that grow from the flowering stems of Orchids.
Breeding systems
Monocots can be classified as perfect (having bisexual flowers), monoecious (having separate male and female flowers on the same plant), dioecious (having flowers of only one sex on an individual) and polygamous (having bisexual flowers with male and/or female flowers on the same plant). Plants that are dioecious have no other option but to mate with different individuals, but in all other cases there is the possibility that an individual's pollen may make contact with its own stigma. For this reason, most plants have genetic mechanisms to prevent fertilization from pollen grains that are too closely related to the stigma (self-incompatibility). The mechanisms of breeding systems occur at the molecular level through a biochemical reaction on the stigma that recognizes genetic differences in pollen grains. Depending on the species, individual plants can self-pollinate, individuals plants can cross-pollinate intraspecifically (between individuals of the same species), or individuals can cross-pollinate interspecifically (between individuals of different species) and hybridize. Orchids are known to have weak barriers to hybridization.
Self-incompatibility
Mating with individuals that are too closely related (i.e. with self) may result in inbreeding depression, so it is usually considered advantageous to cross-pollinate intraspecifically, in which case self-incompatibility is utilized. At least 27 families of monocots have genetic mechanisms to ensure self-incompatibility (SI). The most widespread form of self-incompatibility in monocots is gametophytic, meaning compatibility is determined by the genotype of the pollen grain. There are two described mechanisms of gametophytic self-incompatibility that have been shown to occur in four families of dicots (RNase and S-glycoprotein) but none have been found in monocots. However, there is evidence that orchids have an alternative undescribed mechanism of gametophytic self-incompatibility.
Homomorphic sporophytic self-incompatibility has not yet been discovered in monocots. In this form compatibility is determined by the genotype of the anther from which the pollen grain was created. Heteromorphic sporophytic self-incompatibility, a mechanism in heterostylous flowers, has been shown to occur in only one family of monocots, Pontederiaceae. Late-acting (ovarian) self-incompatibility has been described in Agavaceae, Iridaceae, and Amaryllidaceae.
Grasses have a mechanism of self-incompatibility unique to themselves; they employ two unlinked loci, S and Z. When the alleles at these loci are equivalent between a pollen grain and a stigma on which it lands then the pollen grain will be rejected.
Self-compatibility
Self-compatible (SC) pollination systems are less common than self-incompatibile cross-pollination systems in angiosperms. However, when the probability of cross-pollination is too low it can be advantageous to self-pollinate. Self-pollination is known to be favored in some orchids, rices, and Caulokaempferia coenobialis (Zingiberaceae).
Pollination ecology
Pollination systems in monocots are just as diverse as in dicots. About two thirds of monocots evolved to be zoophilous (animal pollinated). Others are instead water-pollinated or wind-pollinated such as Cyperaceae, Juncaceae, Sparganiaceae, Typhaceae, and most notably Poaceae. These modes evolved to facilitate transfer of the pollen grain onto the stigma. Most zoophilous monocots are pollinator generalists with the most notable exception being the Orchids. Monocot pollen grains are monocolpate, meaning they have one groove; outer surfaces called exines are smooth.
Pollination strategies
All monocots utilize either cross-pollination or self-pollination strategies, as do dicots, but the advantage of either strategy depends on ecological factors such as pollinator abundance and competition. These strategies either promote fertilization with self and suppress fertilization with others resulting in self-pollination, or they suppress fertilization with self and promote fertilization with others resulting in cross-pollination. Strategies also exist to suppress fertilization with other species as reproductive barriers.
Pollination strategies have the same function as breeding systems, however they occur at the ecological level or at the level of floral structure rather than at the molecular level on the stigma through genetic recognition
Cross-pollination (allogamy)
Self-pollination can be prevented by both physical and temporal mechanisms that have evolved in response to the interactions with pollen vectors; these mechanisms make cross-pollination easier to accomplish by lowering the chances of self-pollination. For example, dichogamy, which is the temporal differentiation in the ripening of sexual organs, is common in monocots with both protogynous and protoandrous flowers. Herkogamy, which is the spatial separation of sexual organs, is also present in many monocots.
Self-pollination (autogamy and geitonogamy)
Self-pollination can occur with or without the aid of animals. When animal-mediated, sexual organs will be positioned closer spatially and temporally, inverse to the strategies of dichogamy and herkogamy. However, when self-pollination is self-induced by the flower, some unique mechanisms have evolved. In Caulokaempferia coenobialis (Zingiberaceae), pollen is transported via a drop of oil that forms on the anther and slowly slides down to the stigma. In the orchid, Paphiopedilum parishii, anthers liquify and touch the stigma with the help of gravity rather than a pollinator. Another orchid, Holcoglossum amesianum, rotates its anther in circles to transfer pollen into its stigma cavity.
Apomixis (agamospermy)
Apomixis is asexual reproduction through seeds and does not require pollination. It is distributed throughout the monocot clade in Poales, Asparagales, Liliales, Dioscoreales, and Alismatales. Thus apomixis may have evolved once in a basal ancestor and has since repeatedly become lost.
Pollination syndromes
Pollination syndromes are floral adaptations in response to pollen vectors, such as the production of nectar.
Floral morphology
Flower structure is more uniformly distributed within the monocots. Monocot flowers occur with parts having multiples of three; usually there are three stamen, three petals and three sepals (six tepals), and usually just one stigma. However stamens in twos can be found in Cypripedioideae while single fertile stamens can be found in Philydraceae, Zingiberaceae, and as gynostemium in Orchidacaea. Furthermore, flower structures that evolved to trap insects to accomplish pollination are found in many monocot genera. In relation to flower arrangement alone, plants with perfect flowers should be most likely to self-pollinate while dioecious plants should be most likely to cross-pollinate.
Animal pollination
Zoophily, or animal pollination, is a method of pollination which utilizes animals as pollen vectors.
In order for pollen to affix to animal bodies, a tryphine coating is usually present in zoophilous pollen to achieve an adhesive pollen grain.
Visual attractants of monocot flowers mainly come from the coloration of tepals. However, when species with small green tepals are zoophilous other organs can evolve to be visually attractive such as having colored bracts (Araceae, Cyclanthaceae, and some Arecaceae), otherwise attraction is based on scent only. The similar pigments used in monocot and dicot flower coloration have independently evolved.
Many monocots produce scent to attract pollinators but perhaps not as many as those that produce nectar.
Most zoophilous monocots produce nectar as a reward and this nectar is alike to nectar of dicots. Carpellary septal nectaries are common and unique to monocots. Nonseptal nectaries are most often epithelial and positioned on the perigonal nectaries of tepals when occurring in monocots. Also, nectar can be produced in perigonal unicellular hairs, a trait only observed in monocots. Monocots do not have disc nectaries whereas in dicots they are widespread.
Like dicots, some zoophilous monocots do not produce nectar and instead offer pollen as the main reward. A few even offer other rewards: oils to bees, starchy tissue to beetles, sleeping holes to bees, and a perfume which Euglossini male bees will collect and present on their legs during mating displays. Deceptive flowers that do not offer actual rewards are much more widespread in monocots than dicots, with the most common perpetrator being the orchids. Orchids commonly provide empty nectar spurs. One genus, Ophrys, is known for its ability to mimic female bees to such a degree that it fools male bees into pseudocopulating with the “female” and thereby pollinating the flower.
Wind pollination
Most wind-pollinated plants do not produce nectar, attractive scents, or petals because they are not adapted to pollination by animal vectors. Grasses are a large wind-pollinated group; their stigmas are often feathery to help catch pollen in the wind.
Water pollination
Monocots account for nearly all hydrophilous or water-pollinated plants. These are monocots that are adapted to use water as a vector and constitute most of the aquatic plants. Depending on the species, pollen can either float on the surface and disperse by wind and water currents towards other surface-floating flowers, or pollen can drift underwater to flowers that are submerged. In the later scenario, pollen is without an exine and stigmas are forked.
The flowering bamboo phenomenon
A few species of bamboos can grow for more than 120 years without flowering. Then at once flowering can simultaneously occur in groves across the world, termed gregarious or mast flowering. This is possible because the trigger to flower is genetically determined and because multiple forests can develop from the clones of one individual. The cause of the trigger is still unknown and unpredictable. During anthesis, or flowering, pollination is wind-mediated but bee pollination has been observed in at least 6 species. When pollination is zoophilous flowers can be fragrant and attract large numbers of pollinator-collecting bees to congregate around the inflorescence and take advantage of this new and abundant source of pollen. After anthesis massive die-offs of all sister groves occur within three years of each other and can have devastating effects.
See also
Monocotyledon
Plant Reproduction
Mating System
Self-incompatibility
Self-pollination
Pollination
Pollination Syndrome
Poaceae in Palaeoecological Reconstructions
References
Plant reproduction
Monocots | Monocotyledon reproduction | [
"Biology"
] | 3,258 | [
"Behavior",
"Plant reproduction",
"Plants",
"Reproduction"
] |
56,477,466 | https://en.wikipedia.org/wiki/IXPE | Imaging X-ray Polarimetry Explorer, commonly known as IXPE or SMEX-14, is a space observatory with three identical telescopes designed to measure the polarization of cosmic X-rays of black holes, neutron stars, and pulsars. The observatory, which was launched on 9 December 2021, is an international collaboration between NASA and the Italian Space Agency (ASI). It is part of NASA's Explorers program, which designs low-cost spacecraft to study heliophysics and astrophysics.
The mission will study exotic astronomical objects and permit mapping of the magnetic fields of black holes, neutron stars, pulsars, supernova remnants, magnetars, quasars, and active galactic nuclei. The high-energy X-ray radiation from these objects' surrounding environment can be polarized oscillating in a particular direction. Studying the polarization of X-rays reveals the physics of these objects and can provide insights into the high-temperature environments where they are created.
Overview
The IXPE mission was announced on 3 January 2017 and was launched on 9 December 2021. The international collaboration was signed in June 2017, when the Italian Space Agency (ASI) committed to provide the X-ray polarization detectors. The estimated cost of the mission and its two-year operation is US$188 million (the launch cost is US$50.3 million). The goal of the IXPE mission is to expand understanding of high-energy astrophysical processes and sources, in support of NASA's first science objective in astrophysics: "Discover how the universe works". By obtaining X-ray polarimetry and polarimetric imaging of cosmic sources, IXPE addresses two specific science objectives: to determine the radiation processes and detailed properties of specific cosmic X-ray sources or categories of sources; and to explore general relativistic and quantum effects in extreme environments.
During IXPE's two-year mission, it will study targets such as active galactic nuclei, quasars, pulsars, pulsar wind nebulae, magnetars, accreting X-ray binaries, supernova remnants, and the Galactic Center.
The spacecraft was built by Ball Aerospace & Technologies. The principal investigator is Martin C. Weisskopf of NASA Marshall Space Flight Center; he is the chief scientist for X-ray astronomy at NASA's Marshall Space Flight Center and project scientist for the Chandra X-ray Observatory spacecraft.
Other partners include the McGill University, Massachusetts Institute of Technology (MIT), Roma Tre University, Stanford University, OHB Italia and the University of Colorado Boulder.
Objectives
The technical and science objectives include:
Improve polarization sensitivity by two orders of magnitude over the X-ray polarimeter aboard the Orbiting Solar Observatory 8
Provide simultaneous spectral, spatial, and temporal measurements
Determine the geometry and the emission mechanism of active galactic nuclei and microquasars
Find the magnetic field configuration in magnetars and determine the magnitude of the field
Find the mechanism for X-ray production in pulsars (both isolated and accreting) and the geometry
Determine how particles are accelerated in pulsar wind nebula
Telescopes
The space observatory features three identical telescopes designed to measure the polarization of cosmic X-rays. The polarization-sensitive detector was invented and developed by Italian scientists of the Istituto Nazionale di AstroFisica (INAF) and the Istituto Nazionale di Fisica Nucleare (INFN) and was refined over several years.
Principle
IXPE's payload is a set of three identical imaging X-ray polarimetry systems mounted on a common optical bench and co-aligned with the pointing axis of the spacecraft. Each system operates independently for redundancy and comprises a mirror module assembly that focuses X-rays onto a polarization-sensitive imaging detector developed in Italy. The focal length is achieved using a deployable boom.
The Gas Pixel Detectors (GPD), a type of Micropattern gaseous detector, rely on the anisotropy of the emission direction of photoelectrons produced by polarized photons to gauge with high sensitivity the polarization state of X-rays interacting in a gaseous medium. Position-dependent and energy-dependent polarization maps of such synchrotron-emitting sources will reveal the magnetic-field structure of the X-ray emitting regions. X-ray polarimetric imaging better indicates the magnetic structure in regions of strong electron acceleration. The system is capable to resolve point sources from surrounding nebular emission or from adjacent point sources.
Launch profile
IXPE was launched on 9 December 2021 on a SpaceX Falcon 9 (B1061.5) from LC-39A at NASA's Kennedy Space Center in Florida. The relatively small size and mass of the observatory falls well short of the normal capacity of SpaceX's Falcon 9 launch vehicle. However, Falcon 9 had to work to get IXPE into the correct orbit because IXPE is designed to operate in an almost exactly equatorial orbit with a 0° inclination. Launching from Cape Canaveral, which is located 28.5° above the equator, it was physically impossible to launch directly into a 0.2° equatorial orbit. Instead, the rocket needed to launch due east into a parking orbit and then perform a plane, or inclination, change once in space, as the spacecraft crossed the equator. For Falcon 9, this meant that even the tiny IXPE likely still represented about 20–30% of its maximum theoretical performance () for such a mission profile, while the same launch vehicle is otherwise able to launch about to the same orbit IXPE was targeting when no plane change is needed, while recovering the first stage booster.
IXPE is the first satellite dedicated to measuring the polarization of X-rays from a variety of cosmic sources, such as black holes and neutron stars. The orbit hugging the equator will minimize the X-ray instrument's exposure to radiation in the South Atlantic Anomaly, the region where the inner Van Allen radiation belt comes closest to Earth's surface.
Operations
IXPE is built to last for two years. After that it may be retired and deorbited or given an extended mission.
After launch and deployment of the IXPE spacecraft, NASA pointed the spacecraft at 1ES 1959+650, a black hole, and SMC X-1, a pulsar, for calibration. After that the spacecraft observed its first science target, Cassiopeia A. A first-light image of Cassiopeia A was released on 11 January 2022. 30 targets are planned to be observed during IXPE's first year.
IXPE communicates with Earth via a ground station in Malindi, Kenya. The ground station is owned and operated by the Italian Space Agency.
At present mission operations for IXPE are controlled by the Laboratory for Atmospheric and Space Physics (LASP).
Results
In May 2022 the first study of IXPE hinted the possibility of vacuum birefringence on 4U 0142+61 and in August another study looked at Centaurus A measuring low polarization degree, suggesting that the X-ray emission is coming from a scattering process rather than arising directly from the accelerated particles of the jet. In October 2022 it observed the gamma ray burst GRB 221009A, also known as the "Brightest of all time" (BOAT).
Gallery
See also
Astrophysical X-ray source
Explorer program
GEMS, a similar spacecraft
List of X-ray space telescopes
X-ray astronomy
X-ray telescope
XPoSat - launched around the same time, complements IXPE by observing space events in 2-30 keV range
References
Space telescopes
X-ray telescopes
NASA satellites orbiting Earth
Explorers Program
Spacecraft launched in 2021 | IXPE | [
"Astronomy"
] | 1,568 | [
"Space telescopes"
] |
56,477,657 | https://en.wikipedia.org/wiki/Electrochemical%20coloring%20of%20metals | Electrochemical coloring of metals is a process in which the surface color of metal is changed by electrochemical techniques, i.e. cathodic or anodic polarization. The first method of electrochemical coloring of metals are certainly Nobili's colored rings, discovered by Leopoldo Nobili, an Italian physicist in 1826. In addition to the multicolored coatings mentioned, he has also been able to obtain monochrome coatings, and he called that technique metallocromia. Electrochemical coloring of metals based processes are black, green and blue nickel plating, black chromium plating, black rhodium plating and black ruthenium plating. Anodic oxidation of aluminum, titanium, niobium, tantalum and stainless steel are also electrochemical colouring processes. Multi-colored and green electrolytic patinas for copper and its alloys are also significant.
History
Apart from Leopoldo Nobili, who already in 1824 performed his first experiments related to the appearance of Nobili's rings, Leonhard Elsner, Alexander Watt, Antoine César Becquerel (1788–1878) and Rudolf Christian Böttger (1806–1881) also dealt with the electrochemical coloring of metals in that early period. It should also be mentioned that in 1768. Joseph Priestley (1733–1804) recorded similar phemomen and that the described phenomenon was called Priestley's or fairy rings, but Priestley used a Leiden bottle and a metal spike, and the rings were formed on a metal plate concentrically around the point of an explosive electrical discharge. We also know that George Richards Elkington (1801–1865), otherwise known for his patent for galvanic gilding and silver plating from 1840 patented at least one process of electrochemical coloring of metals (the American J.E .Stareck developed ten variants of his process around 1937). At the end of the 19th century, Lismann (DRP. 93543) and at the beginning of the 20th century, Setlik developed the first electrolytic processes for dyeing copper green, these processes was further developed between the 2 world wars and again after the World War II. Around the same time, the first procedures for electrolytic browning of steel were developed (HL Hollis' patent USPT 621,084 from 1899 was the first attempt in this direction, but Becquerel reported on this already in 1861). While the aforementioned deal with this issue primarily for protection against corrosion, the English patent 106,774 from 1916 and the American patent by T. Rondelli and Q. Sestini USPT 1,386,076 from 1921 are also oriented towards the chemical coloring of steel, and iron as the goal of the procedure.
Black nickel plating was developed around 1905, and between the two wars, black chrome plating (first German patent 1929.GP 607, 420), which saw wider use only from the mid-1950s. After the First World War, the first procedures for anodic oxidation and coloring of anodically oxidized aluminium were developed (1923, 1924.DRP. 413876). In the 1960s, procedures were developed for the anodic oxidation of titanium, a little later niobium and tantalum, and a little bit earlier stainless steel (circa 1957 patent US 2957812 A). Unlike anodically oxidized aluminum, these procedures do not involve an oxide layer that can be colored with special dyes, but interference colors .
Several significant procedures were also developed in the former Soviet Union after the Second World War, the Ukrainian A.P. Eitchis developed several complex, but also original procedures, which included the electrochemical coloring of metals (Kristalit, Iskrit, Sloit, Texturit - His work was strongly influenced by already mentioned J.E.Stareck). Chrome agate and chrome oxide processes were developed in the USSR, they were special versions of black chrome plating.
Basic division of electrochemically obtained colored coatings
Coatings formed by deposition on the cathode
Black nickel plating, blue nickel plating, green nickel plating, black chrome, chrome agate, chrome oxide, black molybdenum, black manganese, black zinc, black platinum, black palladium, black rhodium, blue rhodium, red rhodium, black ruthenium, Elkington solution, Electrocolor process, Bancroft's Blue. Among the coatings that are no longer used due to their toxicity and European ROHS regulations, we can mention coatings based on arsenic (the so-called shiny gray oxide) and lead .
Coatings formed on the anode
Nobili rings, Lismann green for copper and alloys, anodic oxidation of aluminum, magnesium, titanium, niobium, tantalum, tungsten, carbon steel and stainless steel, silver, copper and its alloys, tin, chromium and zinc.
A brief description of several processes
1. Nobilis colored rings
39 gr of lead acetate
100 ml of distilled water
cathode made of platinum or stainless steel (needle), anode nickel-plated or gold-plated copper or brass or polished steel, duration 10 s, distance between cathode and anode 3 mm . An electrolyte of 100 g of litharge dissolved in 0.5 l of water can also be used in which 100 g of NaOH is dissolved. Becquerel used a solution of 200 parts water, 20 potassium hydroxide and 15 litharge.
A. Roseleur used a much milder solution of 200 parts of water, 10 parts of potassium hydroxide and 1 part of litharge.
2. Electrolytic coloring according to Elkington
copper sulfate 75 gr/lit
Sodium hydroxide 75 gr/lit
lactic acid 126ml/lit
copper anodes, 0.25/A per square foot, gives various colors on copper and alloys, depending on the duration of the process, a large number of variations on this process have been developed, the most famous is the American Elektrocolor process developed by J.E.Stareck, Russian literature mentions more than 10 variants
3. Various colors on titanium (anodic oxidation)
A 3% trisodium phosphate solution can be used as a simple electrolyte, a stainless steel cathode, an object as an anode. The colors depend on the DC voltage. It is possible to use numerous other electrolytes - allegedly even Coca-Cola. Straw Yellow/10v - Magenta/29v - Blue/30v - Blue Green/45v - Bright Green/55v - Magenta Red/75v - Gray/110v It is mandatory to do this process with rubber gloves - potentially dangerous voltage.
4. Black nickel plating
nickel sulfate 75 gr/lit
nickel ammonium sulfate 45 gr/lit
zinc sulfate 37.5 gr/lit
ammonium thiocyanate 15 gr / lit
pH 5.6 - 5.9, temp. 55C, 0.5 - 1.5 V, 5 - 20 A /per square foot, nickel carbon anodes
5. Various colors on stainless steel 18 Cr/8 Ni (anodic oxidation)
sulfuric acid 250 ml/lit
sodium bichromate 60 gr/lit
water 1 lit
0.6 A/per square foot, 70 - 95 C, lead cathode, gives brown, blue, purple and green color depending on the duration of the process, there are many variants of this process. According to Russian literature, after processing, the objects should be soaked in a solution of potassium bichromate (5-10%), 5 – 15 minutes, 70 - 90 C solution temperature. According to a Chinese patent, additionally objects can then be treated with a hot sodium waterglass solution (1 - 5%, 95-100 C, 3 - 10 min.). As hexavalent chromium compounds are prohibited for use in the EU based on ROHS regulations and are toxic and carcinogenic, solutions based on molybdate are proposed as a replacement (e.g. molybdate 30-100g/ boric acid 10-18 g/manganese sulfate 0.5 - 5 g/1 liter of water, 0.1 - 20 A/dm2, 0.1–15 minutes).
6. Black color on carbon steel (anodic oxidation)
sodium hydroxide 700 gr
water 1 lit
5 - 10 A/dm2, 60 - 70 C temp., 30 – 40 minutes
7. Black color on copper and alloys (anodic oxidation)
Sodium hydroxide 150 - 200 gr
water 1 lit
up to 2 A/dm2,80-100 C,10 – 30 minutes
8. Krom ahat (gray lines on a black background)
chromium anhydride 300 – 400 gr
barium acetate 5 – 10 gr
zinc acetate 2 – 5 gr
calcium acetate 4 – 8 gr
water 1 liter, 30 - 40 C, 30 - 100A/dm2, duration 10 - 20 min, 6 - 9v, distance object anode 30 - 100mm. A variant of this procedure is the so-called chromium oxide procedure (250 - 300 gr of chromium anhydride, 1 - 5 gr of potassium ferrocyanide, 20 - 100 A/dm2, max. 25 C)
References
Literature
External links
Budija, G.: Collection of formulas for the chemical,electrochemical and heat colouring of metals, the cyanide free immersion plating and electroplating (https://archive.org/details/kemboj-en-2025]), Zagreb 2025
Buchner,G.: Die Metallfärbung und deren Ausführung,Berlin 1901.
Michel,J. La Coloration des metaux,Paris 1931.
Deutsches Kupfer Institut "Chemische Faerbungen von Kupfer und Kupferlegirungen ,Berlin 1974.
Coatings
Electrolysis
Metalworking
Artworks in metal | Electrochemical coloring of metals | [
"Chemistry"
] | 2,106 | [
"Electrochemistry",
"Coatings",
"Electrolysis"
] |
74,926,079 | https://en.wikipedia.org/wiki/Mona%20Berciu | Mona Inesa Berciu is a Romanian-Canadian theoretical condensed matter physicist whose research involves electromagnetic effects in materials, including ferromagnetism, superconductivity, magnetic semiconductors, photonic band gaps, polarons, spintronics, and the quantum Hall effect. She is a professor of physics at the University of British Columbia.
Education and career
Berciu represented Romania in the 1989 International Physics Olympiad, earning an honorable mention and a prize for the best female competitor. She was an undergraduate at the University of Bucharest, where she earned a bachelor's degree in physics in 1994. She came to the University of Toronto for graduate study in physics, earned a master's degree in 1995, and completed her Ph.D. in 1999. Her dissertation, A microscopic model for non-Fermi-liquid behavior and charge carrier pairing in a purely repulsive 2D electron system, was supervised by Sajeev John.
After postdoctoral research with Ravindra N. Bhatt at Princeton University, she joined the University of British Columbia as an assistant professor of physics in 2002. She has been a full professor since 2012.
Recognition
The Canadian Association of Physicists gave Berciu their 2013 CAP Medal for Excellence in Teaching Undergraduate Physics, "in recognition of for her exceptional ability to communicate knowledge and understanding and lead students to high academic achievement in physics through her own example, for her leading role in the Welcome Women (WOW) initiative to recruit female students and for her efforts to generally improve the quality of physics teaching through such work as undertaken by the Carl Weiman Science Education Initiative."
She was named as a Fellow of the American Physical Society (APS) in 2019, after a nomination from the APS Division of Condensed Matter Physics, "for outstanding contributions to the theory of dilute magnetic semiconductors and polarons".
References
External links
Home page
Year of birth missing (living people)
Living people
Romanian emigrants to Canada
Romanian physicists
Romanian women physicists
Canadian physicists
Canadian women physicists
Condensed matter physicists
University of Bucharest alumni
University of Toronto alumni
Academic staff of the University of British Columbia
Fellows of the American Physical Society | Mona Berciu | [
"Physics",
"Materials_science"
] | 432 | [
"Condensed matter physicists",
"Condensed matter physics"
] |
74,926,555 | https://en.wikipedia.org/wiki/Direct%20reduction | In the iron and steel industry, direct reduction is a set of processes for obtaining iron from iron ore, by reducing iron oxides without melting the metal. The resulting product is pre-reduced iron ore.
Historically, direct reduction was used to obtain a mix of iron and slag called a bloom in a bloomery. At the beginning of the 20th century, this process was abandoned in favor of the blast furnace, which produces iron in two stages (reduction-melting to produce cast iron, followed by refining in a converter).
However, various processes were developed in the course of the 20th century and, since the 1970s, the production of pre-reduced iron ore has undergone remarkable industrial development, notably with the rise of the . Designed to replace the blast furnace, these processes have so far only proved profitable in certain economic contexts, which still limits this sector to less than 5% of world steel production.
History
Bloomery
Historically, the reduction of iron ore without smelting is the oldest process for obtaining steel. Low-temperature furnaces, unable to reach the melting temperatures of iron alloys, produce a bloom, a heterogeneous agglomerate of metallic iron more or less impregnated with carbon, gangue, and charcoal. This process was gradually succeeded, from the 1st century in China and the 13th century in Europe, by the blast furnace, which simultaneously reduces and melts iron.
Elaborate low furnaces, such as the tatara or the Catalan forge, survived until the early 19th century. Compared with the indirect process (reduction-melting in the blast furnace, followed by cast-iron refining), these processes only survived when they enjoyed at least one of the following two advantages:
ability to process ores that are incompatible with blast furnaces (such as iron sands that clog blast furnaces, or ores that generate slag that is too pasty to be drained);
a more "reasonable" size than that of giant plants and their constraints (ore and capital requirements, production to sell off, etc.).
Modern direct reduction
More advanced direct reduction processes were developed at the beginning of the 20th century, when it became possible to smelt pre-reduced ores using the Martin-Siemens process or the electric arc furnace. Based on this technical and economic model, a number of processes were industrialized before World War II (the Krupp-Renn process adopted by the Shōwa Steel Works, the Chenot process, etc.). They remained confidential, however, and their profitability was generally debated.
Modern direct reduction processes, based on the use of natural gas instead of coal, were studied intensively in the 1950s. On December 5, 1957, the Mexican company Hylsa started up the first industrial production unit of this type in Monterrey, with the pre-reduced ore obtained destined for smelting in an electric arc furnace. As the production of pre-reduced ore with natural gas was economically viable, several plants were built in the late 1960s. As a cheap supply of natural gas was essential to their profitability, most plants were located in countries with gas deposits, in Latin America (where many were developed) and in the Middle East.
In 1970, worldwide production of pre-reduced iron ore reached 790,000 tonnes. The processes then in operation were the HYL process (680,000 tonnes produced), an SL/RN unit, a Purofer unit, and the first plant to use the Midrex process.
Although profitable and innovative, the processes invented did not ultimately prove to be a technological revolution capable of supplanting the traditional blast furnace-based process. However, the quantity of steel produced from pre-reduced materials grew steadily, outstripping world steel production:
in 1975, NML played a significant role in developing a ‘Direct Reduction Technology’ for producing sponge iron with solid fuel like non-metallurgical coal. This formed the basis of the first commercial sponge iron plant of India.
in 1976, installations in service totalled less than 5 Mt;
in 1985, annual production was 11 Mt for an installed capacity of around 20 Mt, the difference being explained by fluctuations in energy costs;
in 1991, production reached 20 Mt.
in 1995, worldwide production of prereducts passed the 30 Mt mark for the first time.
In 2010, 70 Mt were produced, 14% from HYL processes and 60% from the Midrex process. The latter accounts for most of the growth in natural gas-fired production of pre-reduced products, although since 2005 coal-fired processes have been making a strong comeback, mainly in India.
Packaging of pre-reduced iron ore is evenly divided between sponge iron and briquettes. Sponges are a highly porous metallic product, close to the original ore but highly pyrophoric, which limits their transport. They are therefore often subjected to hot compaction, which improves both product density and handling safety. In 2012, 45% of prereducts were transformed into briquettes in this way.
Chemical reactions
Iron oxide reduction
Iron oxides are reduced in the following sequence:
Fe2O3 → Fe3O4 → FeO → Fe
hematite → magnetite → wustite → iron
Each transition from one oxide to the next is due to two simultaneous high-temperature reduction reactions by carbon monoxide CO or dihydrogen H2:
These temperatures differ from those predicted by the Ellingham diagram. In reality, there is a coupling between carbon monoxide reduction and dihydrogen, so that these reactions work together, with hydrogen significantly improving the efficiency of CO reduction.
Reducing gas production
Coal-fired processes
In coal-fired processes, part of the fuel is first burnt to heat the charge. The product of this combustion is CO2. When the temperature reaches 1,000 °C, the CO2 reacts with the unburned carbon to create CO:
CO2 + C ⇌ 2 CO when T > 1 000 °C (Boudouard reaction)
The production of H2 cannot be achieved by the thermal decomposition of water, as the temperatures involved are too low. Hydrogen is in fact produced along with carbon monoxide by the reaction:
H2O + C → H2 + CO when T > 1 000 °C
These two reducing gas production reactions, which consume 172.45 and 131.4 kJ/mol respectively, are highly endothermic and operate by limiting charge heating.
Natural gas processes
The reducing atmosphere, rich in CO and H2, can be created from the high-temperature cracking of natural gas at around 1100-1150 °C, in the presence of oxidized gases (H2O and CO2) from ore reduction reactors.
CH4 + CO2 → 2 CO + H2
CH4 + H2O → CO + 3 H2
The system that generates the reducing gases is called a "reformer". In the Midrex process, it consists of tubes heated by the combustion of a portion (around a third) of the gas from the reactor.
Procedures
Plants for the production of pre-reduced iron ore are known as direct reduction plants. The principle involves exposing iron ore to the reducing action of a high-temperature gas (around 1000 °C). This gas is composed of carbon monoxide and dihydrogen, the proportions of which depend on the production process.
Generally speaking, there are two main types of processes:
processes where the reducing gas is obtained from natural gas. In this case, the ore is reduced in tanks;
processes where the reducing gas is obtained from coal. The reactor is generally an inclined rotary kiln, similar to those used in cement plants, in which coal is mixed with limestone and ore, then heated.
Another way of classifying processes is to distinguish between those where the reducing gases are produced in specific facilities separate from the reduction reactor - which characterizes most processes using natural gas - and those where the gases are produced inside the fusion reactor: coal-fired processes generally fall into this category. However, many "gas-fired" processes can be fed by gasification units producing a reducing gas from coal.
In addition, since the melting stage is necessary to obtain alloys, reduction-melting processes have been developed which, like blast furnaces, produce a more or less carburized liquid metal. Finally, many more or less experimental processes have been developed.
Tank processes
In these processes, iron ore is brought into contact with reducing gases produced and heated by a separate plant in a closed enclosure. As a result, these processes are naturally suited to the use of natural gas.
Cyclic processes
In these processes, the ore is fed into a tank, where it remains until it is completely reduced. The vessel is then emptied of its pre-reduced ore, and filled with another charge of untreated ore. These processes can therefore be easily extrapolated from laboratory experiments. What's more, their principle, based on batch production, facilitates process control.
Natural gas processes
In natural gas cyclic processes, a unit produces hot reducing gas, which is injected into the reactor. To ensure continuous operation of the unit converting natural gas into reducing gas, several tanks are operated in parallel and with a time lag.
The best-known of this type is HYL I and its improved variant, HYL II. This is the oldest industrial direct gas reduction process, developed in Mexico in 1957 by the Hylsa company.
Retorts
These are exclusively coal-fired processes, with the reducing gases generated inside the reduction vessel. The ore is charged with coal into a closed container. This is then heated until the oxygen present in the ore combines with the carbon before being discharged, mainly in the form of CO or CO2. This production of gas by heating a solid material means that the reactor belongs to the retort category.
The principle is an ancient one: in northern China, the shortage of charcoal led to the development of processes using hard coal before the 4th century. To avoid any contact between iron and sulfur, the brittle element provided by coal, China developed a process that involved placing iron ore in batteries of elongated tubular crucibles and covering them with a mass of coal, which was then burned. This process survived into the 20th century.
More recently, other historic processes have come to the fore, such as that of Adrien Chenot, operational in the 1850s in a number of plants in France and Spain. Successive improvements by Blair, Yutes, Renton, and Verdié are not significant. Among the processes developed is the HOGANAS process, perfected in 1908. Three small units are still operational (as of 2010). Not very productive, it is limited to the production of powdered iron, but as it is slow and operates in closed retorts, it easily achieves the purities required by powder metallurgy.
Other retort processes were developed, such as KINGLOR-METOR, perfected in 1973. Two small units were built in 1978 (closed) and 1981 (probably closed).
Continuous processes
Based on the principle of counter-current piston flow, these processes are the closest to the blast furnace or, more accurately, the stückofen. Hot reducing gases are obtained from natural gas, in a separate unit from the shaft, and injected at the bottom of the shaft, while the ore is charged at the top. The pre-reduced materials are extracted hot, but in solid form, from the bottom of the shaft. This similarity to a blast furnace without its crucible made it one of the first processes explored by metallurgists, but the failures of the German Gurlt in 1857, and the French Eugène Chenot (son of Adrien) around 1862, led to the conclusion that "the reduction of iron ore [...] is therefore [not] possible in large quantities by gas alone".
Developed in the 1970s, the Midrex process is the best example of a continuous direct reduction process. As much a technical success as a commercial one, since 1980 it has accounted for around two-thirds of the world's production of pre-reduced materials. Its similarity to the blast furnace means that it shares some of its advantages, such as high production capacity, and some disadvantages, such as the relative difficulty of controlling several simultaneous reactions in a single reactor (since the nature of the product changes considerably as it travels through the vessel). The strategy of selling turnkey units, combined with a cautious increase in production capacity, has given this process good financial and technical visibility... compared with the often dashed hopes of competing processes.
Its direct competitor, the HYL III process, is the result of a research effort by the Tenova Group (de), heir to the Mexican Hylsa pioneers. Accounting for almost 20% of pre-reduced product production, it differs from the Midrex process in that it features an in-house reforming unit for the production of reducing gases.
Other processes have been developed based on this continuous reactor principle. Some, like ULCORED, are still at the study stage. Most have only been developed in a single country, or by a single company. Others were failures, such as the NSC process, of which a single plant was built in 1984 and converted to HYL III in 1993, ARMCO (a single unit commissioned in 1963 and shut down in 1982) or PUROFER (3 units operational from 1970 to 1979, small-scale production resumed in 1988).
Coal-fired processes are variants of natural gas processes, where the gas can be synthesized from coal in an additional unit. Among these variants, the MxCol, of which one commercial unit in Angul commissioned by Jindal Steel and Power has been operational since 2014, is a Midrex fed by a coal gasification unit. Technically mature but more complex, they are at a disadvantage compared with equivalent gas-fired processes, which require slightly less investment.
Fluidized beds
Given that direct reduction is a chemical exchange between gas and solid, the fluidization of ore by reducing gases is an attractive line of research. However, the changing nature of the constituents, combined with the high temperature and the difficulty of controlling the fluidization phenomenon, make its adoption singularly difficult.
Many processes have been developed on this principle. Some have been technical failures, such as the HIB (a single plant commissioned in 1972, converted to the Midrex in 1981) or economic failures, such as the FIOR process (a single plant commissioned in 1976, mothballed since 2001, the forerunner of FINMET).
Developed in 1991 from the FIOR process, the FINMET process seems more mature, but its expansion has not materialized (two plants were built, and only one was in operation as of 2014). The CIRCORED process, also recent, is similarly stagnant (just one plant built, commissioned in 1999, mothballed in 2012), despite its adaptability to coal (CIRCOFER process, no industrial production).
Rotating furnace processes
Rotation of the reduction furnace may be a design choice intended to circulate the ore through the furnace. It can also play an active part in the chemical reaction by ensuring mixing between the reactants present. Rotary hearth processes, where the ore rests on a fixed bed and travels through a tunnel, fall into the first category. Rotary kiln processes, where the ore is mixed with coal at high temperature, constitute the second category.
Rotary hearth
These processes consist of an annular furnace in which iron ore mixed with coal is circulated. Hot reducing gases flow over, and sometimes through, the charge. The ore is deposited on a tray, or carts, rotating slowly in the furnace. After one rotation, the ore is reduced; it is then discharged and replaced by oxidized ore.
A number of processes have been developed based on this principle. In the 1970s-1980s, the INMETCO process demonstrated only the validity of the idea, with no industrial application. The MAUMEE (or DryIron) process came to fruition in the US with the construction of two small industrial units in the 1990s. Similarly, in Europe, a consortium of Benelux steelmakers developed the COMET process in the laboratory from 1996 to 1998. Despite the consortium's withdrawal from the research program in 1998, a single industrial demonstrator was extrapolated from it, the SIDCOMET, which was discontinued in 2002. RedIron, whose only operational unit was inaugurated in Italy in 2010, also benefits from this research. Japan has adopted the FASTMET process, with the commissioning of three units dedicated to the recovery of iron-rich powders, and is proposing an improved version, the ITmk3 process, with one unit in operation in the United States.
This non-exhaustive list shows that, despite the keen interest shown by steelmakers in developed countries during the 1990s, none of these processes met with commercial success.
Rotary drums
These processes involve high-temperature blending of iron ore and coal powder, with a little limestone to reduce the acidity of the ore. Processes such as Carl Wilhelm Siemens', based on the use of a short drum, first appeared at the end of the 19th century. The tool used then evolved into a long tubular rotary kiln, inspired by those used in cement works, as in the Basset process, developed in the 1930s.
A process of historic importance is the Krupp-Renn. Developed in the 1930s, there were as many as 38 furnaces in 1945 which, although they only had a capacity of 1 Mt/year at the time, were installed all over the world. This process was improved and inspired the German Krupp-CODIR furnaces and the Japanese Kawasaki and Koho processes. Both Japanese processes integrate a pelletizing unit for steel by-products upstream of the rotary furnaces. Two units of each process were built between 1968 (Kawasaki) and 1975 (Koho).
The ACCAR process, developed in the late 1960s and used confidentially until 1987, uses a mixture of 80% coal and 20% oil or gas: the hydrocarbons, although more expensive, enrich the reducing gas with hydrogen. The German Krupp-CODIR process, operational since 1974, has had little more success: only three units have been commissioned. Finally, Indian steelmakers are behind the SIIL, Popurri, Jindal, TDR and OSIL processes, which are simply variants developed to meet specific technical and economic constraints.
Other processes, built on the same principle, failed to develop, such as the Strategic-Udy, consisting of a single plant commissioned in 1963 and shut down in 1964.
The SL/RN process, developed in 1964, dominated coal-fired processes in 2013. In 1997, it accounted for 45% of pre-reduced coal production. In 2012, however, production capacity for this process had fallen to just 1.8 Mt/year, out of a total of 17.06 Mt attributed to coal-fired processes.
Reduction-melting processes
As the smelting stage is necessary to obtain alloys and shape the product, direct reduction processes are frequently combined with downstream smelting facilities.
Most pre-reduced iron ore is smelted in electric furnaces: in 2003, 49 of the 50 Mt produced went into electric furnaces. Process integration is generally highly advanced, to take advantage of the high temperature (over 600 °C) of the prereduct from the direct reduction reactor.
One idea is to carry out the entire reduction-melting process in the arc furnace installed downstream of the reduction plant. Several plasma processes operating above 1530 °C have been devised and sometimes tested. Furnaces can be either non-transferred arc (Plasmasmelt, Plasmared) or transferred arc (ELRED, EPP, SSP, The Toronto System, falling plasma film reactor). All these processes share the electric furnace's advantage of low investment cost, and its disadvantage of using an expensive energy source. In the case of direct reduction, this disadvantage is outweighed by the fact that a great deal of heat is required, both for the reduction process and because of the gangue to be melted.
An alternative to the electric furnace is to melt the pre-reduction with a fuel. The cupola furnace is ideally suited to this task, but since one reason for the existence of direct reduction processes is the non-use of coke, other melting furnaces have emerged. The COREX process, in operation since 1987, consists of a direct-reduction shaft reactor feeding a blast furnace crucible, in which the pre-reduced ore is brought to a liquid smelting state, consuming only coal. This process also produces a hot reducing gas, which can be valorized in a Midrex-type unit. An equivalent to COREX, based on the FINMET fluidized bed instead of the Midrex vessel, is the Korean FINEX process (a contraction of FINMET and COREX). Both processes are in industrial operation at several plants around the world.
Last but not least, a number of reduction-melting furnaces in the same reactor have been studied, but have not yet led to industrial development. For example, the ISARNA process and its derivative HISARNA (a combination of the ISARNA and HISMELT processes), is a cyclonic reactor that performs melting before reduction. These processes have culminated in an industrial demonstrator tested in the Netherlands since 2011. Similarly, Japanese steelmakers joined forces in the 1990s to develop the DIOS process which, like many reduction-fusion processes, is similar to oxygen converters. The TECNORED process, studied in Brazil, also performs reduction-melting in the same vessel, but is more akin to a blast furnace modified to adapt to any type of solid fuel. Of all the processes of this type that have been developed, a single ISASMELT-type industrial unit built in Australia, with a capacity of 0.8 Mt/year, operated from 2005 to 2008 before being dismantled and shipped to China, where it was restarted in 2016.
Economic importance
Controlling capital and material requirements
In the US, where the Midrex process was first developed, direct reduction was seen in the 1960s as a way of breathing new life into electric steelmaking. The techno-economic model of the mini-mill, based on flexibility and reduced plant size, was threatened by a shortage of scrap metal, and a consequent rise in its price. With the same shortage affecting metallurgical coke, a return to the blast furnace route did not seem an attractive solution.
Direct reduction is theoretically well-suited to the use of ores that are less compatible with blast furnaces (such as fine ores that clog furnaces), which are less expensive. It also requires less capital, making it a viable alternative to the two tried-and-tested methods of electric furnaces and blast furnaces.
The comparative table shows that the diversity of processes is also justified by the need for quality materials. The coking plant that feeds a battery of blast furnaces is just as expensive as the blast furnace and requires a specific quality of coal. Conversely, many direct-reduction processes are disadvantaged by the costly transformation of ore into pellets: these cost on average 70% more than raw ore. Finally, gas requirements can significantly increase investment costs: gas produced by a COREX is remarkably well-suited to feeding a Midrex unit, but the attraction of the low investment then fades.
The benefits of direct fuel reduction
Although gas handling and processing are far more economical than converting coal into coke (not to mention the associated constraints, such as bulk handling, high sensitivity of coking plants to production fluctuations, environmental impact, etc.), replacing coke with natural gas only makes direct reduction attractive to steelmakers with cheap gas resources. This point is essential, as European steelmakers pointed out in 1998:"There's no secret: to be competitive, direct reduction requires natural gas at $2 per gigajoule, half the European price."
- L'Usine nouvelle, September 1998, La réduction directe passe au charbon.This explains the development of certain reduction-melting processes which, because of the high temperatures involved, have a surplus of reducing gas. Reduction-melting processes such as the COREX, capable of feeding an ancillary Midrex direct reduction unit, or the Tecnored, are justified by their ability to produce CO-rich gas despite their higher investment cost. In addition, coke oven gas is an essential co-product in the energy strategy of a steel complex: the absence of a coke oven must therefore be compensated for by higher natural gas consumption for downstream tools, notably hot rolling and annealing furnaces.
The worldwide distribution of direct reduction plants is therefore directly correlated with the availability of natural gas and ore. In 2007, the breakdown was as follows:
natural gas processes are concentrated in Latin America (where many have already been developed) and the Middle East;
coal-fired processes are remarkably successful in India, maintaining the proportion of steel produced by direct reduction despite the strong development of the Chinese steel industry.
China, a country with gigantic needs and a deficit of scrap metal, and Europe, lacking competitive ore and fuels, have never invested massively in these processes, remaining faithful to the blast furnace route. The United States, meanwhile, has always had a few units, but since 2012, the exploitation of shale gas has given a new impetus to natural gas processes.
However, because direct reduction uses much more hydrogen as a reducing agent than blast furnaces (which is very clear for natural gas processes), it produces much less CO2, a greenhouse gas. This advantage has motivated the development of ULCOS processes in developed countries, such as HISARNA, ULCORED, and others. The emergence of mature gas treatment technologies, such as pressure swing adsorption or amine gas treating, has also rekindled the interest of researchers. In addition to reducing CO2 emissions, pure hydrogen processes such as Hybrit are being actively studied with a view to decarbonizing the steel industry.
Notes
References
See also
Bibliography
Amit Chatterjee, Sponge Iron Production By Direct Reduction Of Iron Oxide, PHI Learning Private Limited, 2010, 353 p. (, read online archive)
"Process technology followed for sponge iron" archive, Environment Compliance Assistance Centre (ECAC)
"World direct reduction statistics" archive of August 29th, 2005, Midrex, 2001.
"World direct reduction statistics " archive, Midrex, 2012.
J. Feinman, "Direct Reduction and Smelting Processes " archive, The AISE Steel Foundation, 1999.
"Direct Reduced Iron " archive, The Institute for Industrial Productivity.
Related articles
Loupe (sidérurgie)
Krupp-Renn Process
Direct reduced iron.
Direct reduction (blast furnace)
Histoire de la production de l'acier.
Ore deposits
Chemistry
Iron
Metallurgy
Blast furnaces
Metallurgical processes | Direct reduction | [
"Chemistry",
"Materials_science",
"Engineering"
] | 5,485 | [
"Metallurgical processes",
"Metallurgy",
"History of metallurgy",
"Materials science",
"Blast furnaces",
"nan"
] |
74,927,899 | https://en.wikipedia.org/wiki/Craniformin | Craniformin is a chemical compound found in some species of puffball mushrooms, notably Calvatia craniiformis, the brain puffball.
References
Formamides
Methylsulfates
Diazo compounds
Phenols | Craniformin | [
"Chemistry"
] | 47 | [] |
74,928,211 | https://en.wikipedia.org/wiki/Rho%20Fornacis | Rho Fornacis (ρ For) is a star of apparent magnitude +5.54 in the constellation of Fornax, the furnace.
It is found, according to the new reduction of the parallax data from Hipparcos, to 269 light years of the Solar System.
Rho Fornacis is a yellow-orange giant of spectral type G6III with an effective temperature of 4884 K.
It is similar, though somewhat hotter, than β Fornacis and π Fornacis, stars also in Fornax.
The diameter of Rho Fornacis is 9.9 times larger than the solar diameter but its mass is barely 1% greater than that of the Sun.
Its age is estimated at 5180 ± 3170 million years.
Rho Fornacis is a thick disk star, unlike most stars in our environment. Arcturus (α Boötis) and ε Fornacis, the latter in this same constellation, are examples of thick disk stars.
The eccentricity of its orbit around the Galactic Center (e = 0.56) is considerably greater than that of the Sun (e = 0.16), star of the thin disk.
Consequently, it shows a low metallicity—relative abundance of elements heavier than helium—, less than half that of the solar ([Fe/H] = -0 ,35).
Elements such as aluminum, calcium and sodium are equally deficient.
As in other similar stars, the oxygen/iron ratio is higher than in the Sun ([O/H] = 0.33).
References
Fornax
G-type giants
Fornacis, Rho
023940
1184
017738 | Rho Fornacis | [
"Astronomy"
] | 347 | [
"Fornax",
"Constellations"
] |
74,928,223 | https://en.wikipedia.org/wiki/Dogxim | Dogxim, or Graxorra in Portuguese, was a female canid hybrid between a Pampas fox and a domesticated dog that was discovered in Brazil during 2021. The canid showed a mixture of fox and dog behaviours, and a team of geneticists led by Thales Renato Ochotorena de Freitas and Rafael Kretschmer announced in 2023 that she was a distinct hybrid genetically that "represents the first documented case of hybridization between these two [fox and dog] species".
She was popularized as the first "fox"-dog hybrid documented in the world, although the Pampas fox and other South American foxes are not true foxes, being instead closer genetically to wolf-like canids, which include dogs.
Dogxim was kept at the animal care centre Mantenedouro São Braz. However, when the scientists requested fresh photographs of the canid in September 2023, the caretakers reported that she had died six months prior to the request. The Brazilian government then issued an investigation into the cause of death.
Discovery
Dogxim was run over by an automobile in Vacaria, Rio Grande do Sul in 2021. She was found by the Environmental Patrol who took her to the veterinary hospital of the Federal University of Rio Grande do Sul. After medical treatment for her injuries, she was moved to the university's Center for Conservation and Rehabilitation of Wild Animals for full recovery. Scientists recollected that in 2019 biologist Herbert Hasse Junior had observed two strange canids in the same region and they speculated that Dogxim might be one of the two.
The size of Dogxim was approximately that of a medium-sized dog. Her eyes were dark brown and her body was dark brown with specks of white and grey, and had wiry hairs. By November 2021, she was transferred to Mantenedouro São Braz, an animal care centre in Santa Maria. The caretakers there noticed unusual characteristics and features in the canid that are a mixture those of wild canids and dogs. The ultimate give away came after full recovery when she showed preference for climbing in bushes to ground roaming. The veterinarian and conservationist, Flávia Ferrari, realised the need for biological assessment for which geneticists Thales Renato Ochotorena de Freitas, of the Federal University of Rio Grande do Sul, and Rafael Kretschmer, of the Federal University of Pelotas, were consulted. The genetic study established the canid as a hybrid individual, which was reported in the journal Animals on 3 August 2023.
Name
The name Dogxim is derived from dog and graxaim-do-campo, a Portuguese name for the Pampas fox. She also was given a Portuguese name, graxorra, combining the prefix for the Pampas fox and the suffix taken from cachorra that means female dog.
Behaviour
Dogxim possessed a mixture of wild canid features and dog features. She had noticeably large pointed ears resembling that of foxes. She refused to eat dog food, but savoured rats. The pupils of her eyes resembled those of dogs and she barked exactly like dogs do. She did not show the behavior of a domestic dog, but neither did she show the aggression generally displayed by wild canids, acting more shy and introverted than violent. She easily adapted to human environment during her hospitalisation. Although she was sterilized during her medical care, scientists believed that she had been capable of reproduction.
Identification
Four species of wild canids are known in southern Brazil: the bush dog (Speothos venaticus), the maned wolf (Chrysocyon brachyurus), the crab-eating fox (Cerdocyon thous), and the Pampas fox (Lycalopex gymnocercus). It was thought that Dogxim could not have come from the bush dog as that species is not present in the Vacaria region where she was found. The largest canid in southern Brazil is the maned wolf, but Dogxim had no particular resemblance to that species. Dogxim did have common features with both the crab-eating fox and the Pampas fox, but precise identification would require genetic analysis.
Genetics
Genetic analysis indicated that Dogxim had 76 chromosomes, which exactly matches the number in the maned wolf. However, as the chromosomes lacked the common structural appearances (phenotype) of that species, it appeared likely that the two canids were not related. It was found that Dogxim's 76 chromosomes came from the haploid chromosomes, 39 from the dog and 37 from the Pampas fox, the first evidence of hybridization between these two different canid species. Dogs have 78 chromosomes (39 haploid pairs), while the Pampas fox, 74 (37 haploid pairs). Additional evidence of hybridisation was the presence of two different X chromosomes indicating their origins from two species.
In mammals such as dogs and humans, mitochondria are inherited exclusively from the mothers. Mitochondrial DNA (mtDNA) of Dogxim indicated that her mitochondria came from the Pampas fox. Thus, Dogxim came from a crossbreeding between a Pampas fox mother and a dog father of an unknown breed.
Death
In August 2023, Scientists asked the caretakers at Mantenedouro São Braz for fresh pictures of Dogxim. The caretakers replied that she had died six months prior to the request. The time and nature of her death were never reported. Veterinarian and conservationist Ferrari recalled that the canid had "no indications of any health problems" after her recovery. Six months after the injury, she had been noted as completely healed. The Brazilian government issued concerns on the cause of death. The Secretariat of Environment and Infrastructure (SEMA) is conducting the investigation.
See also
List of individual dogs
References
Canid hybrids
Carnivorans of Brazil
South American foxes
Intergeneric hybrids
Individual canines
Individual animals in Brazil
2023 animal deaths
Domesticated foxes | Dogxim | [
"Biology"
] | 1,238 | [
"Intergeneric hybrids",
"Hybrid organisms"
] |
74,928,292 | https://en.wikipedia.org/wiki/Water%20pollution%20in%20Haiti | Pollution of water resources in Haiti, as with many developing countries, is a major concern. The main cause of water pollution in the country is major deficiencies in the collection of solid waste and the absence or dysfunction of wastewater sanitation. In addition, the considerable increase in the population over the last decades coupled with a lack of urban planning by successive authorities in the country has led to massive degradation in the environment, while affecting the quality of available water resources. As a result, surface water and shallow groundwater are increasingly contaminated by micro-organisms such as bacteria, protozoa and viruses, exposing men, women and children to cholera, typhoid, Cryptosporidiosis and all kinds of waterborne diseases.
Causes of pollution
Untreated sewages
Haiti does not have a collective system for the collection and treatment of wastewater. Sanitation, when it exists in Haiti, is autonomous in nature where the individual is responsible for the management and evacuation of the water he produces. As a result, gray water generally ends up in open drainage channels that have been sized only for stormwater drainage. On the other hand, when drainage channels do not exist, they are then evacuated on the ground near the houses. This promotes contamination by runoff and infiltration of surface water and groundwater.
As for black water, the observation is overwhelming: in Haiti only 26% of the population has access to improved sanitation systems, with a partition of 34.5% in urban areas and 17% in rural areas. Note that more than half of these toilets were not built on septic tanks, and they are not regularly emptied. In addition, the emptying of sanitary systems, when it is done, is most often carried out by manual drainers and the excreta is simply thrown into canals or waterways. Indeed, the country has a single functional excreta treatment center with a capacity of 500 m3 per day, for a population of nearly 12,000,000 inhabitants and an area of 27,750 km2.
Other problems
In recent years, Haiti has experienced significant demographic growth and unplanned urbanization from rural areas to urban areas, particularly the Port-au-Prince metropolitan region. This has led to the creation of numerous slums without access to the most basic services. These areas are also major producers of solid waste, which is generally dumped in ravines, street corners, roadsides and other open spaces. In fact, studies of waste management in Port-au-Prince showed that 87.7% of the poorest households used ravines to dispose of their waste.
All these poor sanitation practices combined with shallow aquifers and fractured rocks result in widespread contamination, either through runoff and/or infiltration of polluted effluents, of the country's ground and surface water resources.
ways of curbing water pollution in Haiti
Addressing water pollution in Haiti requires a multifaceted approach that considers both immediate interventions and long-term solutions. Here are several strategies that can help curb water pollution in Haiti:
Improving Sanitation Infrastructure: Promoting the construction and maintenance of proper sanitation facilities such as toilets and sewage treatment systems can prevent untreated sewage from contaminating water sources.
Implementing Waste Management Practices: Establishing effective waste collection and disposal systems to reduce plastic and solid waste pollution in rivers, lakes, and coastal waters.
Promoting Sustainable Agriculture: Encouraging the adoption of organic farming practices and reducing the use of chemical fertilizers and pesticides to minimize agricultural runoff into water bodies.
Protecting Watershed Areas: Implementing measures to protect and restore critical watershed areas through reforestation and erosion control to prevent sedimentation and runoff pollution.
Educating Communities: Conducting educational campaigns to raise awareness about the importance of clean water, proper waste disposal, and hygiene practices among communities.
Regulating Industrial Discharges: Enforcing regulations on industrial wastewater discharge to ensure that pollutants from factories and industries do not contaminate water sources.
Investing in Water Treatment Technologies: Installing and maintaining water treatment facilities to improve access to clean and safe drinking water for communities.
Collaborating with International Organizations: Partnering with international organizations and NGOs to provide technical expertise, funding, and resources for water pollution control projects.
Quality of water resources
No recent survey has been carried out at the national level on the quality of water used daily by the population. However, according to a survey carried out in April 2012 in the Department of Artibonite, out of 108 sources tested for water quality, 2/3 of them presented traces of E. Coli (Escherichia coli) and 25.9%. had a concentration of more than 100 MPN/100mL which is very high-risk levels for human health.
Other studies carried out in the three main cities of the country, namely Port-au-Prince, Cap-Haïtien and Les Cayes, have shown the presence of microorganisms such as Giardia and Cryptosporidium at levels dangerous for the population. Indeed, values of 4 to 1274 cryptosporidium oocysts and 741 to 6088 Cryptosporidium oocysts were found in Port-au-Prince and Cap-Haïtien, in waters intended for use by the population.
The presence of these microorganisms in Haiti's waters is a marker of faecal contamination.
Related diseases
Water-borne diseases such as diarrhea, cholera, cryptosporidiosis, among others, are very common in the country. In this sense, they present a high health risk for the most vulnerable.
Easily catchable diseases, such as diarrhea and those resulting in malnutrition, kill between 20% and 28% of children aged 0 to 5, respectively. Cryptosporidiosis is a common cause of diarrhea in Haiti. It is responsible for 17.5% of acute diarrhea affecting children under 2 years old and 30% of chronic diarrhea affecting people with HIV.
Between October 2010 and February 2019, an epidemic of cholera introduced by Nepalese soldiers caused the death of nearly 10,000 people and infected more than 820,000. Only, to find a resurgence in October 2022 which have already affected 4 department in the country, with a total of 6,814 suspected cases of which 5,628 have been hospitalized and cause 144 deaths as of 6 November 2022.
References
11. World Bank. (2020). Water Supply, Sanitation, and Hygiene in Haiti. Retrieved from World Bank Haiti Water.
Water pollution in Haiti
Water pollution in Haiti
Water pollution in Haiti | Water pollution in Haiti | [
"Chemistry",
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"Water pollution by country",
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74,929,430 | https://en.wikipedia.org/wiki/General%20Company%20for%20Glass%20and%20Refractories | The glass factory, officially called the General Company for Glass and Refractories, is an Iraqi government factory for the production of glass, refractories, and ceramics. It was established in 1971, at a cost of 6,700,000 dinars, in the city of Ramadi, affiliated with the Ministry of Industry and Minerals, 80 kilometers west of Baghdad. The production of 9,000 tons of glass panels and bottles began in an initial phase in February 1972. The workers were 1,375, then they reached 5,000 employees. In 1978, the factory relied on the raw materials found in that region, and in 1979 the production capacity reached 22,700 tons. Of glass, the director of the factory stated that its production was “classified from the finest types of glass.” After the Battle of the Mother of All Battles (also known as the Persian Gulf War) in 1991, and the imposition of an economic blockade on many raw materials, the government was forced to import materials with hard currency, and to buy used glass debris from citizens. It collected 2,325 tons between May and August.
In 1992, the factory was able to produce 90% of what it had produced before the war. The factory has been closed since 2003, and 2,500 employees belong to it. The factory contains 3 complexes: a glass complex, a ceramics complex, and a refractory complex. The factory was damaged as a result of the Islamic State's control over it after the Battle of Ramadi, which resulted in the destruction of most of the production factories. The company's director, Nazim Reda Hamad, said, "This company was subjected to acts of sabotage and destruction due to the entry of terrorist groups into it, which led to the destruction of most of the production plants. The company's staff were able to limit the damage and thus it was included in the investment files, which were presented based on the ministry's instructions." The factory is close to the Anbar desert, which is rich in local raw materials. The glass factory derives its water needs through direct pipes from the Euphrates River, which is very close by. The Technical Institute was also established in Ramadi to train and graduate intermediate technicians in glass technology. The purpose of its establishment was firstly: to qualify technical staff who are being appointed for the first time or who want to change the nature of their work, and secondly: to hold various technical, financial, commercial and administrative training courses for the company's employees. Economic expert Abdul Majeed Al-Anbari said, “The Ramadi Glass Factory constitutes a major investment in the natural resources available in Anbar... This industrial institution produces glass extracted from the city of Ramadi, which is considered one of the purest glass in the world.”
The site and its construction
Natural glass is an ancient material, and Iraq is considered one of the oldest glass-manufacturing countries, as its manufacture began in Iraq more than 3,500 years ago. Iraq has a large reserve of pure white sand suitable for the manufacture of glass. Italian engineers said that the soil of Anbar is one of the regions in the world richest in silicic acid. Iraq was one of the few Arab countries that took the initiative to benefit from glass sand. It was planned that the glass factory would be established in Rutba and not Ramadi, which is about 300 km from Rutba. The preference for the location of Ramadi over Rutba has several reasons, including that Rutba is located in the middle of the desert. Western Region, where it is difficult to obtain water, and making glass requires a lot of water. Producing one ton of glass requires 98,000 liters of water. Baghdad Magazine reported in 1967 that geologists “surveyed the Wadi Houran area in Rutba and found that there were approximately 5 million tons of sand suitable for making glass at a depth of 10 meters.” In 1969, the chief engineer of the glass factory project said that the first phase, which includes the project management building, garages, sedimentation basins, and the factory fence, has now been completed, and that the second phase, which includes the fuel tanks, cooling tower, and glass paste making shops, has now been 60% completed, and work has begun. In the third stage. A team of 60 Russian experts were used to build the factory, who trained Iraqi cadres to work in it and manage it. The Journal of the California Institute of International Studies reported that Iraq would no longer need to import glass. In 1987, a contract for the expansion of the factory was awarded to Belgian contractors, so production increased and products diversified. During the imposition of the economic blockade on Iraq, Glass Industry magazine reported that a Russian team went to the glass factory in an effort to modernize and expand it. On March 18, 2021, investment contracts were concluded between the glass factory and Russian companies to rehabilitate and operate the company's factories and establish new ones.
Ramadi west of the Euphrates
The city of Ramadi was limited to the eastern side of the Euphrates, and when the glass factory was established west of the Euphrates, 7 kilometers away, urban growth began in the 1970s near the factory, and then the area increased in growth after the establishment of Anbar University. The area in which the glass factory is located is called the glass factory area, according to the municipal designation, and it is an industrial area.
References
Al Anbar Governorate
Companies of Iraq
Glassmaking companies | General Company for Glass and Refractories | [
"Materials_science",
"Engineering"
] | 1,131 | [
"Glass engineering and science",
"Glassmaking companies",
"Engineering companies"
] |
74,930,053 | https://en.wikipedia.org/wiki/Low%20anterior%20hairline | Low anterior hairline is a dysmorphic feature in which the frontal hairline which defines the top and sides of the forehead is unusually low. This can mean that either the distance between the trichion (hairline) and glabella at the midline is more than 2 SD below the mean, or that this distance is apparently (subjectively) decreased.
Conditions
Low anterior hairline is seen in the following conditions and syndromes:
8q22.1 microdeletion syndrome
Adams-Oliver syndrome 2
Agenesis of the corpus callosum with peripheral neuropathy
ALG11-congenital disorder of glycosylation
Barber-Say syndrome
Blepharophimosis - intellectual disability syndrome, Verloes type
Bohring-Opitz syndrome
Cataract - congenital heart disease - neural tube defect syndrome
Cerebellar atrophy, visual impairment, and psychomotor retardation
Coffin-Siris syndrome 5 and 12
COG7 congenital disorder of glycosylation
Congenital lactic acidosis, Saguenay-Lac-Saint-Jean type
Cornelia de Lange syndrome 3 and 5
Craniosynostosis 6
Deficiency of alpha-mannosidase
Deletion of long arm of chromosome 18
DOORS syndrome
Dysmorphism-conductive hearing loss-heart defect syndrome
Ectodermal dysplasia 13, hair/tooth type
Fanconi anemia, complementation group S
Focal facial dermal dysplasia type III
Fontaine progeroid syndrome
Hereditary spastic paraplegia 49
Intellectual disability, autosomal dominant 14, 42, and 52
KBG syndrome
Lissencephaly 7 with cerebellar hypoplasia
Megalocornea-intellectual disability syndrome
MEGF8-related Carpenter syndrome
Microcephaly, short stature, and impaired glucose metabolism 1
Muenke syndrome
Nicolaides-Baraitser syndrome
Pontocerebellar hypoplasia, IIA 17
Rubinstein-Taybi syndrome due to CREBBP mutations
Saethre-Chotzen syndrome
SCARF syndrome
Skin creases, congenital symmetric circumferential, 2
Spondyloepimetaphyseal dysplasia, Bieganski type
Spondyloepimetaphyseal dysplasia, Genevieve type
TCF12-related craniosynostosis
Vertebral anomalies and variable endocrine and T-cell dysfunction
Warburg Micro syndrome 2, 3, and 4
Zimmermann-Laband syndrome 1 and 3
See also
High anterior hairline
References
Anatomical pathology
Hair
Face | Low anterior hairline | [
"Biology"
] | 532 | [
"Organ systems",
"Hair"
] |
74,931,769 | https://en.wikipedia.org/wiki/PSLV-C41 | PSLV-C41 was the 43rd mission of the Indian Polar Satellite Launch Vehicle (PSLV) rocket. It was launched on Thursday, April 12, 2018, at 04:04 Hrs (IST) by the Indian Space Research Organisation (ISRO) from the first launch pad of the Satish Dhawan Space Centre at Sriharikota, Andhra Pradesh. This was the 12th mission to use the PSLV XL configuration.
This mission launched IRNSS-1I navigation satellite into orbit. The satellite is intended to replace the failed IRNSS-1A, and complete the constellation of geosynchronous navigation satellites after IRNSS-1H failed to do so. The satellite was successfully infected into orbit 19 minutes after lift-off. ISRO Chairman K. Sivan described the mission as a success and congratulated the scientists behind it.
Payload
Like its predecessor, IRNSS-1I has two types of payloads, navigation payload and the ranging payload. The navigation payload transmits navigation service signals to the users. This payload is operating in L5 band and S band. A highly accurate Rubidium atomic clock is part of the navigation payload of the satellite. Failure of these Rubidium atomic clocks was the reason for IRNSS-1A to be deemed unfit. The satellite contains corner cube retroreflectors used for LASER ranging.
Launch
Launched on April 12, 2018,
Ignition of the core stage, followed by the ignition of the six strap-ones.
After 70 seconds, at an altitude of 23.6 km, the boosters separated.
Core stage separated after 110 seconds, at an altitude of 55 km.
At 203 seconds, at 113&km, second stage ignited.
After the payload fairing, the second stage separated at an altitude of 131.5&km.
At 264 seconds, 132 km, third stage ignited, followed by a third stage separation at 599 seconds and 183 km height.
At 609 seconds, 185 km, fourth stage is ignited.
At 454.4 km, fourth stage is cut off. Soon after, the satellite is injected into a sub geosynchronous transfer orbit, which is 284 km at perigee and 20650 km at apogee. The maneuver took place above the island of New Guinea.
References
Spaceflight | PSLV-C41 | [
"Astronomy"
] | 471 | [
"Spaceflight",
"Outer space"
] |
74,932,167 | https://en.wikipedia.org/wiki/G%20Doradus | G Doradus (HD 37297; HR 1917; 28 G. Doradus) is a spectroscopic binary located in the southern constellation Dorado, the dolphinfish. It has an apparent magnitude of 5.34, making it faintly visible to the naked eye under ideal conditions. The system is located relatively close at a distance of 234 light-years based on Gaia DR3 parallax measurements but it is receding with a heliocentric radial velocity of approximately . At its current distance, G Doradus' brightness is diminished by a quarter of a magnitude due to interstellar extinction and it has an absolute magnitude of +1.08. The bayer designation "G Doradus" was not assigned by Benjamin Gould or Lacaille. It merely arose due to the designation assigned by Gould; 28 G. Doradus.
The visible component has a stellar classification of G8/K0 III, indicating that it is an evolved star with the characteristics of a G8 and K0 giant star. It has 3.47 times the mass of the Sun but at the age of 556 million years, it has expanded to 10.5 times the radius of the Sun. It radiates 48.4 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of , giving it an orangish-yellow hue when viewed in the night sky. G Doradus is slightly metal deficient with an iron abundance of [Fe/H] = −0.20 and it spins too slowly for its projected rotational velocity to be measured accurately.
G Doradus is a single-lined spectroscopic binary; the components – which have a separation of 0.32 AU – take 181 days to circle each other in an elliptical orbit, but the orbit is not well constrained. Although only the primary can be observed in the spectrum, the masses of both components can be determined. Krachieva et al. (1980) derives a mass of for the companion, which might be an A-type star.
References
Spectroscopic binaries
G-type giants
K-type giants
Dorado
Doradus, G
Doradus, 28
PD-64 00456
037297
026001
1917
149304313 | G Doradus | [
"Astronomy"
] | 456 | [
"Dorado",
"Constellations"
] |
74,932,282 | https://en.wikipedia.org/wiki/Ebro%20Hydrographic%20Confederation | The Ebro Hydrographic Confederation (in Spanish: Confederación Hidrográfica del Ebro, CHE) is the organization that manages, regulates and maintains the water and irrigation of the Ebro hydrographic basin (northeastern Spain). The organization's headquarters are in Zaragoza and it was the first institution created in the world with the objective of managing an entire river basin in a unitary manner.
History
In 1913, the First National Irrigation Congress was held in Zaragoza, exposing the idea of setting up a community group of an economic and supra-regional nature through the federation of the agricultural, commercial and industrial associations of the whole area subject to the influence of the Ebro.
In 1926, during the dictatorship of Primo de Rivera, the Confederaciones Hidrográficas were created under the name of Confederaciones Sindicales Hidrográficas. Article 1 of the founding Royal Decree states that:In all the hydrographic basins in which the Administration declares it convenient or in which at least 70% of its agricultural and industrial wealth, affected by the use of its flowing waters, requests it, the Confederación Sindical Hidrográfica will be formed.The Confederación Sindical Hidrográfica del Ebro was the first to be set up, by Royal Decree of March 5, 1926, and its first Technical Director was the engineer Manuel Lorenzo Pardo, a follower of the ideas of Joaquín Costa, the great instigator of its founding.
In 1931, the government of the Republic restructured the Ebro Hydrographic Confederation, renaming it the Mancomunidad Hidrográfica del Ebro (Ebro Hydrographic Commonwealth). Manuel Lorenzo Pardo was dismissed and replaced by Félix de los Ríos. In March 1936 he was replaced by Nicolás Liria Almor. In 1932 the Mancomunidad Hidrográfica del Ebro was renamed as Delegación de Servicios Hidráulicos del Ebro and in 1934 it was again renamed Confederación Hidrográfica del Ebro.
General information
Nowadays, the CHE is an autonomous agency under the Ministry of Ecological Transition. The functions of this agency are regulated in Article 25 of Royal Decree 927/1988, which approves the Regulations of the Public Administration of Water and Hydrological Planning.
These functions are the following:
The preparation of the basin hydrological plan, as well as its monitoring and revision.
The administration and control of the hydraulic public domain.
The administration and control of uses of general interest or affecting more than one Autonomous Community.
The project, construction and operation of the works carried out with charge to the own funds of the Agency, and those that are entrusted to them by the State.
Those deriving from agreements with Autonomous Communities, local corporations and other public or private entities, or from those signed with individuals.
The Ebro Confederation is also responsible for economic and ecological problems, such as zebra mussels and other introduced animal and plant species, and for providing users with information on the measures that can be taken in the use of boats, contained in the navigation regulations. It is an autonomous body under the Ministry of the Environment. The functions of this agency are regulated in article 25 of Royal Decree 927/1988, which approves the Regulations of the Public Administration of Water and Hydrological Planning.
Scope
The Ebro river basin is located in the NE quadrant of the Iberian Peninsula and covers a total surface area of 85,362 km2, of which 445 km2 are in Andorra, 502 km2 in France and the rest in Spain. It is the largest river basin in Spain, representing 17.3% of the Spanish peninsular territory. Its natural limits are: to the north the Cantabrian Mountains and the Pyrenees, to the southeast the Iberian System and to the east the Coastal-Catalan chain.
It is drained by the Ebro river which, with a total length of 910 km, runs NW-SE, from the Cantabrian Mountains to the Mediterranean, where it flows into a magnificent delta. On its way it collects water from the Pyrenees and Cantabrian mountains on its left bank through important tributaries, such as the Aragón, Gállego, Segre, etc. and on its right bank it receives tributaries from the Sistema Ibérico, normally less abundant, such as the Oja, Iregua, Jalón or Guadalope. The scope of action is very complex, affecting numerous communities and even interacting with administrations of countries such as France or Andorra. For example, the Segre river, one of the main tributaries, rises in the French Alta Cerdanya, crosses mountainous areas with numerous lagoons and springs and in turn receives tributaries such as the Valltoba, the Llosa river, the Quer, the Noguera Pallaresa, the Noguera Ribagorzana and the Cinca. Even at the local level, as shown by the helophytic vegetation that surrounds them, the saline streams and lagoons are sometimes remarkable. In total, there are about 12,000 km of main river network.
In the basin there are numerous seasonal flood lakes, lakes, and lagoons. The most famous lakes and lagoons are mainly in the mountainous areas, the so-called ibones or estanys of the Pyrenees, small in size but of great beauty.
Surface area: 85 362 km2.
Main rivers: 347
Length of rivers: 12 000 km
Inhabitants of the basin according to 2005 census: 3 019 176
Length of rivers: 12 000 km
Estimated surface water supply to the natural regime from 1940/41 to 1985/86:
Maximum 29 726 hm³
Average 18 217 hm³
Minimum 8 393 hm³
This large and varied territory is home to some 3 019 176 inhabitants, which represents a population density of 33 inhabitants/km2, well below the Spanish average (78 inhabitants/km2). Almost half of the population is concentrated in the cities of Zaragoza, Vitoria, Logroño, Pamplona, Huesca and Lérida. There is a concentration of population in the riparian areas in the center of the valley and large areas empty of human population in the Iberian System, the interior steppes, the interior pre-Pyrenees and the Pyrenees.
Wetlands
In the middle stretch of the river there are a large number of lagoons that are fed directly from the river aquifer due to its natural dynamics, which causes the water to circulate through the ground. Where the ground is below the water table, lagoons form in the meanders abandoned by the Ebro or its tributaries or in hollows of the land due to subsidence because the subsoil plaster is dissolved by the groundwater and ends up collapsing forming chasms or sinkholes that when water emerges are popularly called "Ojos" (Eyes). They are part of this abundant set present or buried for cultivation, for example the lagoons of Larralde, Ojo del Fraile, Ojo del Cura and Galachos, all around Zaragoza capital, but they are numerous in any other province of the riverbed. These lagoons or flood lakes are more common in the middle stretch of the Ebro.
There are also numerous endorheic lagoons such as the Sariñena lagoon in Huesca, the Montcornés lagoon in Lérida or the salty lagoon of Chiprana (Zaragoza). The most famous and largest in the area of the Ebro Hydrographic Confederation is the Gallocanta lagoon, located in an endorheic basin, with no external outlet of 541 km2 of basin, which forms one (when it is completely full) or three lagoons depending on the amount of rainfall it receives. The endorheic lagoons that still persist are the remains of the Cenozoic seas or Pliocene residual lakes and usually have a very characteristic and rare endemic fauna and flora with some large species such as the crane, flamingo, or the alcaraván.
Among the wetland projects are the restoration and conditioning of the El Cañizar lake in Villarquemado, (Teruel), and that of Bayas, in Miranda de Ebro (Burgos), completed in 2010; the improvement of the Ojos de Pontil, in Rueda de Jalón (Zaragoza) and the conditioning of the wetland environment in La Sima, in Rubielos de la Cérida (Teruel), both completed in 2011. The organization is also carrying out the environmental restoration of the wetland of the Guaso riverbank on the right bank of the Ara river, in Aínsa (Huesca) and the improvement and conservation of the Larralde pond (Zaragoza) and the restoration of the riverbed of the Queiles river in Los Fayos (Zaragoza).
But the great wetland of the basin is located in the Mediterranean, the Ebro Delta, of 7,736 hectares. It is a Ramsar Convention site, ZEPA area and Tierras del Ebro Biosphere Reserve.
Confederation reservoirs
Mequinenza reservoir: 1,530 hm³ (1965), lower Ebro section
Ebro reservoir: 540 hm³ (1952), headwaters of the Ebro river
Yesa reservoir: 446.86 hm³ (1959) - Yesa dam enlarged 1 100 hm³, Aragón river.
Mediano reservoir: 436.35 hm³ (1973), Cínca river.
Itoiz reservoir: 418 hm³ (2010)*, Iratí river, tributary of the Aragón.
Rialb reservoir: 402 hm³ (2000), Segre river.
El Grado I reservoir: 399.48 hm³ (1969), Cínca river.
Santa Ana reservoir: 236.60 hm³ (1961), Noguera-Ribagorzana.
La Sotonera reservoir: 189.38 hm³ (1963), Astón-Sotón river with waters of the Gállego.
Oliana reservoir: 101.10 hm³ (1959), Segre river.
Joaquín Costa reservoir or Barasona reservoir: 91.70 hm³ (1932), Ésera river.
La Tranquera reservoir: 84.17 hm³ (1960), Piedra river, tributary of the Jalón.
Caspe reservoir: 81.62 hm³ (1991), Guadalope river.
Ribarroja: lower stretch of the Ebro.
Mansilla reservoir: 68 hm³ (1960). Najerilla river. La Rioja
Pajares reservoir: 35.29 hm³ (1995), Lumbreras river. La Rioja
González Lacasa or Ortigosa reservoir: 33 hm³ (1962). Albercos river. La Rioja
El Val reservoir: 24 hm³ (1997), Val river with waters of the Queiles.
Headquarters
From October 1926 Regino Borobio Ojeda was the consulting architect of the CHE for which he carried out in the Ebro basin projects of agricultural farms, garages, schools, housing and offices in reservoirs. In 1929 he designed and built the Ebro Hydrographic Confederation Pavilion for the Barcelona Universal Exposition.
Initially the CHE was installed in premises distributed in 7 different buildings. From 1928 it was installed in a building at number 20, Paseo de Sagasta, according to a project by Pascual Bravo. In 1933 it needed an extension of 6,000 m2.
On February 4, 1933, the competition for preliminary projects for the CHE headquarters was announced. On April 13, 1933, the jury decided and the work was awarded to Regino Borobio Ojeda and José Borobio Ojeda. Work began in April 1936 and was completed in December 1946. The building is functional. It is located at Paseo de Sagasta, 24–26.
See also
Guadalquivir Hydrographic Confederation
Júcar Hydrographic Confederation
Tagus Hydrographic Confederation
Ebro valley
Ebro sedimentary basin
References
Bibliography
(in Spanish)
UTRERA CARO, Sebastián Félix, La incidencia ambiental de las obras hidráulicas: régimen jurídico, Librería-Editorial Dykinson, 2002, 310 pp. ISBN 848155913X, 9788481559132 (in Spanish)
PNILLA NAVARRO, Vicente, Gestión y usos del agua en la cuenca del Ebro en el siglo XX, Universidad de Zaragoza, 2008, 759 pp. ISBN 847733997X, 9788477339977 (in Spanish)
LORENZO PARDO, Manuel, Por el Pantano del Ebro: un convencido más, 1918, 24 pp. (in Spanish)
LORENZO PARDO, Manuel, Uriarte: recuerdos de la vida de un gran ingeniero, Tipografía del Heraldo, 1919, 237 pp. (in Spanish)
LORENZO PARDO, Manuel, Aforo de corrientes, Espasa-Calpe, 1926, 35 pp. (in Spanish)
LORENZO PARDO, Manuel, Nueva política hidráulica: la Confederación del Ebro, Campañía ibero-Americana de publicaciones, 1930, 214 pp. (in Spanish)
LORENZO PARDO, Manuel, Manuel Lorenzo Pardo (1881-1953): escritos publicados en la Revista de Obras Públicas, Colegio de Ingenieros de Caminos, Canales y Puertos, 2003, 151 pp. ISBN 8438002471, 9788438002476 (in Spanish)
BOROBIO OJEDA, Regino, BOROBIO OJEDA, José, Edificio de la Confederación hidrográgica del Ebro: Zaragoza 1933, Servicio Publicaciones ETSA, 1999, 63 pp. ISBN 8489713200, 9788489713208 (in Spanish)
External links
Libro Digital del Agua (in Spanish)
Visor Geográfico del Sistema Integrado de Información del Agua (in Spanish)
(in Spanish)
Página de la Confederación Hidrográfica del Ebro (in Spanish)
Unión de entidades para el cumplimiento de la Directiva de Aguas en la cuenca del Ebro (CuencaAzul) (in Spanish)
Confederación Hidrográfica del Ebro en la Gran Enciclopedia Aragonesa (in Spanish)
Ebro basin
Hydrography
Zaragoza
European drainage basins of the Mediterranean Sea
Rivers of Aragon
Rivers of Burgos
Rivers of La Rioja (Spain) | Ebro Hydrographic Confederation | [
"Environmental_science"
] | 3,038 | [
"Hydrography",
"Hydrology"
] |
74,932,775 | https://en.wikipedia.org/wiki/Direct%20reduction%20%28blast%20furnace%29 | Direct reduction is the fraction of iron oxide reduction that occurs in a blast furnace due to the presence of coke carbon, while the remainder - indirect reduction - consists mainly of carbon monoxide from coke combustion.
It should also be noted that many non-ferrous oxides are reduced by this type of reaction in a blast furnace. This reaction is therefore essential to the operation of historical processes for the production of non-ferrous metals by non-steel blast furnaces (i.e. blast furnaces dedicated to the production of ferromanganese, ferrosilicon, etc., which have now disappeared).
Direct-reduction steelmaking processes that bring metal oxides into contact with carbon (typically those based on the use of hard coal or charcoal) also exploit this chemical reaction. In fact, at first glance, many of them seem to use only this reaction. Processes that historically competed with blast furnaces, such as the Catalan forge, have been assimilated into this reaction. But modern direct reduction processes are often based on the exclusive use of reducing gases: in this case, their name takes on the exact opposite meaning to that of the chemical reaction.
Definition
For blast furnaces, direct reduction corresponds to the reduction of oxides by the carbon in the coke. However, in practice, direct reduction only plays a significant role in the final stage of iron reduction in a blast furnace, by helping to reduce wustite (FeO) to iron. In this case, the chemical reaction can be trivially described as follows:
FeO + C → Fe + CO consuming 155,15 kJ/mol
However, "in the solid state, there is virtually no reaction in the absence of gases, even between finely ground iron ore and coal powders. In other words, it seems certain that the reaction takes place via gases". This means that direct reduction most probably corresponds to the following chain of reactions:
FeO + CO → Fe + CO2 producing 17,45 kJ/mol (reduction by CO)
CO2 + C ⇌ 2 CO consuming 172,45 kJ/mol (Boudouard reaction)
Roles
This reaction accounts for around half of the transformation of wustite FeO into iron, and removes 30% of the total oxygen supplied, mainly in the form of iron oxide Fe2O3. This mode of wustite reduction is highly endothermic, whereas the reduction of iron oxides by CO is slightly exothermic (+155.15 kJ/mol vs. -17.45 kJ/mol), so it is essential to keep it to a minimum.
This reaction concerns all the iron oxides present in a blast furnace, but also manganese(II) oxides (Mno), silica (SiO2), chromium, vanadium and titanium, which are partially reduced in blast furnaces. These chemical reactions are described below:
MnO + C → Mn + CO consuming 282,4 kJ/mol à 1 400 °C (begins above 1,000°C and involves half of the manganese present in the charge)
SiO2 + 2 C → Si + 2 CO consuming 655,5 kJ/mol (begins above 1 500 °C)
Chromium and vanadium behave like manganese, titanium like silicon. As for the other iron oxides, their direct reduction is of negligible importance. This can be written as:
3 Fe2O3 + C → 2 Fe3O4 + CO consuming 118,821 kJ/mol
Fe3O4 + C → 3 FeO + CO consuming 209,256 kJ/mol
In non-steel blast furnaces, dedicated to the production of ferroalloys, direct reduction is fundamental. For example, for ferronickel production, both direct reduction reactions are used:
NiO + C → Ni + CO above 445 °C
FeO + C → Fe + CO above 800 °C
So, although nickel reduces slightly more easily than iron, it cannot be reduced and cast independently of iron.
Notes
References
Iron
Blast furnaces
Metallurgy
Steelmaking | Direct reduction (blast furnace) | [
"Chemistry",
"Materials_science",
"Engineering"
] | 854 | [
"Metallurgical processes",
"Metallurgy",
"Steelmaking",
"History of metallurgy",
"Materials science",
"Blast furnaces",
"nan"
] |
74,933,054 | https://en.wikipedia.org/wiki/Pi2%20Doradus | {{DISPLAYTITLE:Pi2 Doradus}}
Pi2 Doradus, Latinized from π2 Doradus, is a solitary star located in the southern constellation Doradus. It is faintly visible to the naked eye as a yellow-hued point of light with an apparent magnitude of 5.38. The object is located relatively close at a distance of 277 light-years based on Gaia DR3 parallax measurements, but it is receding with a heliocentric radial velocity of approximately . At its current distance, Pi2 Doradus' brightness is diminished by 0.27 magnitudes due to interstellar extinction and it has an absolute magnitude of +0.78.
Pi2 Doradus has a stellar classification of G8 III, indicating that it is an evolved G-type giant star. It is a red clump star that is currently on the horizontal branch—fusing helium at its stellar core. It has 1.8 times the mass of the Sun but, at the age of 1.61 billion years, it has expanded to 9.84 times the radius of the Sun. It radiates 51.1 times the luminosity of the Sun from its photosphere at an effective temperature of Pi2 Doradus is metal deficient with an iron abundance of [Fe/H] = −0.26 or roughly 55% of the Sun's. Like many giant stars Pi2 Doradus spins slowly, having a projected rotational velocity lower than .
References
G-type giants
Horizontal-branch stars
Dorado
Doradus, Pi2
Doradus, 42
CD-69 00392
046116
030565
2327
167126852 | Pi2 Doradus | [
"Astronomy"
] | 344 | [
"Dorado",
"Constellations"
] |
74,933,186 | https://en.wikipedia.org/wiki/Eta3%20Fornacis | {{DISPLAYTITLE:Eta3 Fornacis}}
Eta3 Fornacis (η3 Fornacis) is an orange giant in the constellation of Fornax. The star has a spectral type of K2III and an apparent magnitude of 5.47. The star is visually close to, but unrelated with the similar stars η2 Fornacis and η1 Fornacis. The star is located at approximately 489 light years away with a luminosity of about , and is a suspected binary system with the primary being the orange giant.
References
Fornax
Fornacis, Eta2
K-type giants
017829
0851
013265 | Eta3 Fornacis | [
"Astronomy"
] | 139 | [
"Fornax",
"Constellations"
] |
74,933,406 | https://en.wikipedia.org/wiki/Emilia%20Morosan | Emilia Morosan (also Moroșan, born 1976) is a Romanian-American condensed matter physicist whose research involves the synthesis of quantum materials, including quantum criticality and unconventional superconductors. She is also known for her discovery of super-strong titanium gold alloys. She is a professor at Rice University.
Education and career
Morosan was born in 1976 in Suceava, and studied physics at Alexandru Ioan Cuza University in Iași, Romania, earning a bachelor's degree in 1999. She completed a Ph.D. in physics and astronomy at Iowa State University in 2005. Her doctoral dissertation, Field-induced magnetic phase transitions and correlated electronic states in the hexagonal RAgGe and RPtIn series, was supervised by Paul C. Canfield.
After postdoctoral research in chemistry at Princeton University, Morosan joined Rice University in 2007, as an assistant professor with a joint appointment in the Department of Chemistry and the Department of Physics and Astronomy, her primary affiliation. She was promoted to associate professor in 2013, adding another affiliation in the Department of Materials Science and Nanoengineering. Her promotion to full professor in 2015 added a fourth affiliation, in the Department of Electrical and Chemical Engineering. She is also a member of the Rice Center for Quantum Materials.
Recognition
Morosan was a 2009 recipient of the Presidential Early Career Awards for Scientists and Engineers. She was named as a Fellow of the American Physical Society (APS) in 2018, after a nomination from the APS Division of Condensed Matter Physics, "for experimental contributions to the understanding of correlated magnetic and superconducting materials, through the synthesis and study of unconventional magnetic systems, heavy fermion compounds and superconductors". She is also an Alexander von Humboldt fellow and a National Academy of Sciences Kavli Frontiers Fellow.
References
External links
Morosan Research Group
1976 births
Living people
People from Suceava
Romanian emigrants to the United States
Romanian physicists
Romanian women physicists
American physicists
American women physicists
Condensed matter physicists
Alexandru Ioan Cuza University alumni
Iowa State University alumni
Rice University faculty
Fellows of the American Physical Society
Recipients of the Presidential Early Career Award for Scientists and Engineers | Emilia Morosan | [
"Physics",
"Materials_science"
] | 447 | [
"Condensed matter physicists",
"Condensed matter physics"
] |
74,933,569 | https://en.wikipedia.org/wiki/Donald%20W.%20Brenner | Donald W. Brenner is a Kobe Distinguished Professor and Head of the Department of Materials Science and Engineering at North Carolina State University. His research focuses on computational studies of materials for extreme environments, high entropy ceramics, tribology and tribochemistry, shock and high strain rate dynamics, nuclear materials, and self-assembled monolayers.
Research and career
Donald W. Brenner is best known for his development of the reactive empirical bond order (REBO) interatomic potential, which was a precursor to ReaxFF and similar many-body reactive potentials. After receiving his Ph.D. in Chemistry Brenner was a member of the research staff in the Theoretical Chemistry Section at the U.S. Naval Research Laboratory in Washington DC before joining the faculty at the North Carolina State University.
His honors include the 2002 Feynman Prize in Nanotechnology (theory), the 2013 Alcoa Foundation Distinguished Engineering Achievement Award, and the 2016 Alexander Quarles Holladay Medal for Excellence. He is also an editor of the "Handbook of Nanoscience, Engineering and Technology, three editions", W. Goddard, D. Brenner, S. Lyshevski and G. Iafrate, Eds., CRC Press (2002, 2007 and 2012).
Education
B.S. in Chemistry from the State University of New York in 1982
Ph.D. in Chemistry from Pennsylvania State University in 1987
References
Materials scientists and engineers
North Carolina State University faculty
Living people
Year of birth missing (living people) | Donald W. Brenner | [
"Materials_science",
"Engineering"
] | 316 | [
"Materials scientists and engineers",
"Materials science"
] |
74,934,050 | https://en.wikipedia.org/wiki/Carme%20Jordi | Carme Jordi is a Catalan astronomer. She is a teacher in the Department of Astronomy and Meteorology at the University of Barcelona. She is a member of the Gaia science team, advising the European Space Agency on the scientific aspects of their missions.
References
Year of birth missing (living people)
Living people
Astronomers
Astronomers from Catalonia
Women astronomers
Academic staff of the University of Barcelona | Carme Jordi | [
"Astronomy"
] | 77 | [
"Astronomers",
"Astronomy stubs",
"Women astronomers",
"People associated with astronomy",
"Astronomer stubs"
] |
74,935,727 | https://en.wikipedia.org/wiki/Taiwan%20sleeper%20shark | The Taiwan sleeper shark (Somniosus cheni) is a small sleeper shark from the western North Pacific Ocean around Taiwan. It is only known from a single adult specimen, a pregnant female with 33 embryos, which was caught in 2017.
References
Fish described in 2020
Somniosus
Species known from a single specimen | Taiwan sleeper shark | [
"Biology"
] | 67 | [
"Individual organisms",
"Species known from a single specimen"
] |
74,936,187 | https://en.wikipedia.org/wiki/Deuremidevir | Deuremidevir, also known as VV116, is a nucleoside analogue antiviral drug. It is administrated through oral tablets, which contain the hydrobromide salt of this drug.
The drug is a deuterated tri-isobutyrate of GS-441524, the active metabolite of remdesivir. It was first described in a November 2020 preprint by a team including members of Wuhan Institute of Virology and Vigonvita. It completed a phase 3 trial in 2022. Results from a separate Phase 3 trial conducted in mainland China from October 2022 to January 2023 suggested that deuremidevir may shorten the duration of COVID-19 symptoms in non-hospitalized adults with mild-to-moderate disease compared to placebo. Junshi, which markets the drug, received conditional approval from China's National Medical Products Administration in January 2023.
In November 2023, in response to viral mutations and changing characteristics of infection, the WHO adjusted its treatment guidelines. Among other changes, the use of deuremidevir was recommended against, except for clinical trials.
Research
In preclinical studies, a single high dose of the drug (at least 1.0 g/kg) was shown to be tolerated in rats and dogs.
References
Anti–RNA virus drugs
Antiviral drugs
Deuterated compounds
Isobutyrate esters
Nitriles
Nucleosides
COVID-19 drug development | Deuremidevir | [
"Chemistry",
"Biology"
] | 307 | [
"Antiviral drugs",
"Biocides",
"Drug discovery",
"Functional groups",
"COVID-19 drug development",
"Nitriles"
] |
74,936,212 | https://en.wikipedia.org/wiki/SN%20H0pe | SN H0pe (pronounced: Supernova Hope) is a Type Ia supernova discovered in 2023, at a redshift of z=1.78. It is a supernova discovered in a gravitationally lensed subject system, being itself a triply lensed object. Its name, H0pe, comes from its proposed utility in determination of the Hubble Constant (H0) that would allow determination of H0 in the distant universe and compare it with local determinations; and hopefully resolve Hubble tension, the difference in such determinations with local Type Ia supernovae and those based on the very distant Cosmic Microwave Background. The supernova exploded when the universe was 3.5 billion years old, rather than at today's date of 13.8 billion years old. The supernova progenitor was a white dwarf star, the progenitor of all Type Ia supernovae. The gravitational lens is galaxy cluster PLCK G165.7+67.0 (at a redshift of z=0.35), which lensed the supernova and its host galaxy.
The determination for the Hubble Constant (H0) using this Type Ia supernova was 75.4 kilometers per second per megaparsec. This greatly agrees with the determination of H0 with local Type Ia supernova of 73 kilometers per second per megaparsec. And this is at variance with the determination from the Cosmic Microwave Background and baryon acoustic oscillations, of 67 kilometers per second per megaparsec. Thus not resolving the Hubble tension, but instead reinforcing the difference. This determination of H0 from a multiply-lensed Type Ia supernova represents the first such precision measurement.
The supernova is located in the galaxy PLCK G165.7+67.0 Arc 1 (Arc 1 for short) located at redshift z=1.78, behind the lensing cluster PLCK G165.7+67.0 (G165 for short) located at redshift z=0.35, and is triply imaged, each image called Arc 1a, Arc 1b, Arc 1c. This galaxy is part of a compact group of galaxies, of 6 members, 4 of which surround the host galaxy. This group 6 of galaxies is part of 11 galaxies that are imaged by the lens, each referred to as Arc 1, Arc 2, etc. The host galaxy is the dominant galaxy in its compact group. The lens system is located in the constellation of Ursa Major.
References
External links
NASA/IPAC Extragalactic Database (NED): PLCK G165.7+67.0
SIMBAD: (CNL2018) PLCK G165.7+67.0 lens -- Cluster of Galaxies
Supernovae
Ursa Major
2023 in outer space | SN H0pe | [
"Chemistry",
"Astronomy"
] | 591 | [
"Supernovae",
"Ursa Major",
"Astronomical events",
"Constellations",
"Explosions"
] |
74,936,885 | https://en.wikipedia.org/wiki/Dry%20shipper | A dry shipper, or cryoshipper, is a container specifically engineered to transport biological specimens at cryogenic temperatures utilizing the vapor phase of liquid nitrogen.
Function
The architecture of a dry shipper encompasses two primary components: an internal canister and an external protective shell. The inner canister, designed to hold biological specimens, is positioned within the vapor phase of the liquid nitrogen. This configuration ensures that the specimens are maintained at temperatures below -150 °C for prolonged durations. A distinctive feature of dry shippers is their ability to avert direct contact between samples and liquid nitrogen, reducing risks of contamination and ensuring consistent cryogenic conditions during transit.
Applications
Dry shippers serve various sectors in both the scientific and medical arenas. In the realm of reproductive medicine, these containers facilitate the transportation of delicate biological entities, including human ova and embryos. Within the research landscape, they are employed to carry materials such as spermatozoa or preimplantation embryos of genetically modified mouse strains, safeguarding the integrity and viability of these research assets during their journey. Moreover, biobanks, which archive diverse biological specimens for subsequent scientific exploration, utilize dry shippers to dispatch and acquire samples from researchers worldwide.
Alternative for specimen transport
One common alternative to dry shippers is using dry ice. This method reduces package weight and costs since there's no need for return shipping, unlike with dry shippers. However, at -80 °C, dry ice might not provide a temperature low enough for all specimens. For instance, while cryopreserved mouse spermatozoa can handle this temperature for short periods without losing their fertilization capacity, cryopreserved mouse embryos require colder environments, such as those below -150 °C in dry shippers, to maintain their quality. Another method is shipping freeze-dried samples at ambient temperatures, as seen with freeze-dried mouse spermatozoa. This can be more cost-effective, but many samples, when freeze-dried, experience a notable decline in quality, limiting its applicability.
See also
Cryoconservation of animal genetic resources
References
External links
Capacities of different dry shippers illustrated by the Florida State University
Laboratory mouse strains
Transport
Cryogenics
Genetically modified organisms | Dry shipper | [
"Physics",
"Engineering",
"Biology"
] | 451 | [
"Applied and interdisciplinary physics",
"Genetically modified organisms",
"Cryogenics",
"Genetic engineering",
"Physical systems",
"Transport"
] |
74,938,415 | https://en.wikipedia.org/wiki/Simnotrelvir/ritonavir | Simnotrelvir/ritonavir (trade name Xiannuoxin) is a pharmaceutical drug used for the treatment of COVID-19. Simnotrelvir/ritonavir is a combination drug of simnotrelvir, an inhibitor of SARS-CoV-2 3CLpro, and ritonavir, a CYP3A inhibitor.
It was developed by Simcere Pharmaceutical and conditionally approved in China by the National Medical Products Administration (NMPA) in January 2023. Results for the phase Ib trial are available. In a phase II/III trial, it reduced the duration of symptoms by a median of 36 hours compared to placebo.
See also
Nirmatrelvir/ritonavir
References
External links
NHSA slideshow, also shows adverse effect data from phase II/III
Antiviral drugs
Combination antiviral drugs
COVID-19 drug development | Simnotrelvir/ritonavir | [
"Chemistry",
"Biology"
] | 187 | [
"Antiviral drugs",
"COVID-19 drug development",
"Biocides",
"Drug discovery"
] |
74,939,785 | https://en.wikipedia.org/wiki/Ray%20Baughman | Ray Baughman is an American chemist and academic, currently holding the Robert A. Welch Distinguished Chair in Chemistry and serving as the Director of the Alan G. MacDiarmid NanoTech Institute at the University of Texas at Dallas. He earned his B.S. in physics from Carnegie Mellon University and his Ph.D. in Materials Science from Harvard University.
With more than 100 issued U.S. patents and over 450 refereed publications, he has made notable contributions to the field of nanotechnology. Baughman is a member of the National Academy of Engineering and The Academy of Medicine, Engineering and Science of Texas.
In 2005, Discover magazine ranked Baughman's carbon nanotube yarns and carbon nanotube sheets as the eighth-most important scientific discovery of the year. The sheets and yarns were noted in the Scientific American 50.
References
American chemists
Nanotechnologists
Carnegie Mellon University alumni
Harvard University alumni
University of Texas at Dallas faculty
Living people
Year of birth missing (living people) | Ray Baughman | [
"Materials_science"
] | 208 | [
"Nanotechnology",
"Nanotechnologists"
] |
74,939,996 | https://en.wikipedia.org/wiki/KdpD/KdpE%20two-component%20system | The KdpD/KdpE two-component system is a regulatory system involved in controlling potassium transport and intracellular osmolarity of pathogenic bacteria. It plays an important role in potassium transport for osmoregulation of bacteria. In some bacteria, it can act as a virulence factor and acquire new adaptations from different selective pressures in the environment. It is also demonstrated to maintain internal pH, stress responses, enzyme activation, and gene expression. K+ ions are used for necessary biological processes and can generate a negative electric potential on the cytoplasmic side of the plasma membrane. There are different uptake systems for K+ ions, but the specific mechanisms vary between species.
Physiological significance
As previously mentioned, the KdpD/KdpE system is mainly responsible for the regulation of potassium concentrations within the cell to maintain homeostasis. This system is induced and repressed by quorum molecules, nutrient levels, pH, and ATP concentrations. It can be triggered when there is a lack of potassium ions in the cell, which may be sensed by a decrease in turgor pressure. Interestingly, the kdpFABC gene is reportedly only activated by salts and not sugar, despite both of them increasing osmolarity. This system has a higher affinity for potassium ions compared to average potassium pumps.
The KdpD/KdpE system can contribute to an organism's virulence factor and aid in longer survival. In a study, they examined a strain of avian pathogenic E.coli, AE17ΔKdpDE, and created deletion mutants that affected the KdpD/KdpE system. They found that the deletion mutants, when compared to the WT, had decreased motility, fewer flagellum, altered metabolic pathways, and assembly of movement mechanisms. Since the deletion mutant's motility was significantly underdeveloped, it majorly decreased the virulence of the avian E.coli. Another study inserted the KdpD/KdpE system gene from Photorhadbus asymbiotica into E. coli via a transposition, which resulted in E. coli being able to evade the host cells and not perish by phagocytosis.
Components of the system
KdpD, a sensor kinase, is sensitive to changes in extracellular concentrations of potassium. KdpD is a homodimer consisting of four transmembrane domains, an N-terminal cytoplasmic domain, and a C-terminal cytoplasmic domain. KdpD possesses autokinase, phosphotransferase, and protein phosphatase activity. KdpD undergoes autophosphorylation due to fluctuations in the concentration of potassium. The phosphorylated KdpD-P activates KdpE.
KdpE, a transcriptional regulator, regulates the expression of genes containing high-affinity potassium transport systems. KdpE is a cytoplasmic, homodimer protein. KdpE is phosphorylated by KdpD-P. The activated KdpE-P, a transcription factor, binds to the kdpFABC operon encoding high-affinity potassium transporters.
Activation mechanism
The early models of KdpD stimulus proposed that KdpD sensed changes in turgor pressure. It was later found that the intracellular concentration of potassium affects the autophosphorylation of KdpD. High concentrations of intracellular potassium inhibit the autophosphorylation of KdpD. KdpD also detects changes in intracellular ionic strength. Higher concentrations of extracellular salts stimulate KdpD phosphorylation. The N-terminal domain contains two parts (Walker A & B) that act as ATP binding sites. The intracellular level of ATP affects the autophosphorylation of KdpD. Accessory proteins like UspC, act as scaffolding proteins during salt stress. UspC belongs to a family of scaffolding proteins called universal stress proteins. UspC stabilizes the KdpD/KdpE complex during phosphotransferase activity.
Gene expression regulation
The activated KdpE-P acts as a transcriptional activator by attaching to the operon of the kdpFABC gene. The resulting KdpFABC complex is a high-affinity potassium P-Type ATPase. This ATPase transports potassium intracellularly against the electrochemical gradient using ATP. The KdpF subunit stabilizes the transport complex. The KdpA subunit is responsible for the binding and translocation of potassium ions. The KdpB subunit is responsible for the hydrolysis of ATP to provide energy for translocation. The KdpC subunit is an inner membrane protein with no known function.
Examples of bacterial species
KdpD/KdpE two-component system (TCS) is something that can be found in many bacteria genera/species. A few examples of bacteria that use this system are Escherichia coli, Staphylococcus aureus, and Mycobacterium.
KdpD/KdpE is a TCS system that is found in Escherichia coli and produces K+ transporter Kdp-ATPase. This TCS system was characterized first in the bacterial species of E. coli. The transporter is used as a scavenging system for K+ when it is extremely limited. The TCS system for E. coli has four distinct proteins from one single operon, kdpFABC. The element that regulates the TCS is KdpD/E and is located downstream from the gene KdpC. When there is a K+ limitation, typically from an added salt, KdpD histidine kinase autophosphorylation and the response regulator, KdpE, receive the phosphoryl group. After which affinity increases by 23 base pairs in the sequence upstream from the promoter kdpFABC triggers transcription. This system is used in many gram-negative and gram-positive bacteria.
Currently, KdpD/E is a TCS found in Staphylococcus aureus. This shows repression on transcription for kdpFABC. This happens in all conditions of K+ and brings to attention that KdpFABC is not a major transporter for K+. When KdpD/E becomes inactivated transcription becomes altered for virulence genes. This alteration can affect many different genes including, but not limited to Spa, geh, hla, etc. KdpE binds directly to promoter regions of these genes to regulate transcription for them. KdpD/E transcript levels can be directly related to K+ concentration externally. The S. aureus can modulate infection status by using K+ external stimuli from the environment. The transcript level of KdpD/E can also become activated by Agr/RNAIII when in the post-exponential phase which was confirmed through Rot.
Kdp system is found in many different Mycobacterium species including M. tuberculosis, M. avium, M. bovis, M. smegmatis, M. marinum, and others. The Kdp although is not contained within the M. leprae and M. ulcerans spp. The KdpD/KdpE TCS is not a well-characterized system for the spp. smegmatis because there are many different types of TCS in many different types of Mycobacterium spp. The KdpD/KdpE is a TCS in Mycobacterial species that can regulate potassium homeostasis, regulation mechanism and function for target genes that are located downstream that help with Infections from Mycobacteria. The system could be a target for antibiotic resistance for the mycobacterial infection because the major differences within the potassium uptake systems of eukaryotes and prokaryotes. In these spp. the KdpE binds to the promoter region for kdpFABC operon (PkdpF) and KdpF coding sequence for Mycobacteria is found.
Research and applications
The KdpD/KdpE system is often altered for genetic experiments in virulence and pathogenicity. For example, an experiment took the genes for the KdpD/KdpE system and inserted them into avian pathogenic E.coli cells using a transposon and compared them to an unaltered group. The insertion mutants were less likely to be killed via phagocytosis and had an effect on the cells' metabolism, global transcription, and flagellar assembly. In another study, the genes of the KdpD/KdpE system from Photorhabdus asymbiotica were put into a lab strain of E.coli via a transposon. They observed that the previously susceptible E.coli strain was now able to resist phagocytic killing and longer persist against host cells.
References
Cellular processes | KdpD/KdpE two-component system | [
"Biology"
] | 1,851 | [
"Cellular processes"
] |
74,940,367 | https://en.wikipedia.org/wiki/Teesside%20Beam%20Mill | Teesside Beam Mill (TBM) is a steel reheating and rolling plant located at Lackenby, on Teesside, North Yorkshire, England. The plant was set up in the 1950s by the Dorman Long company and began full production in 1958, making beams for building projects. The plant produces around of steel products per year, and is the United Kingdom's only producer of large steel sections for the building industry.
History
The Teesside Beam Mill was developed after the Second World War, on a strip of land at Lackenby, sandwiched between the Middlesbrough to Redcar railway line to the north, and the A1085 trunk road to the south. The narrow land measured across, providing some in total, with the buildings arranged diagonally between the two transport modes so as maximise land space. Groundwork for the beam plant was started by Dorman Long in 1954, with the mill being built from 1955 onwards. The mill was completed in 1958, with an eventual cost of £18 million. It was built adjacent to the Lackenby steel plant to enable steel ingots to be shipped in to the facility from the open-hearth plant next door, and was opened by Alexander Fleck who was chairman of ICI (ICI had a new plant under construction at nearby Wilton).
Originally the plant rolled steel for the bridge building industry, but later the plant specialised in beams for the construction industry. Its first project was to supply steel beams of length for the Catterick Bypass of the A1 road in North Yorkshire, in 1958. Another of its earlier projects was to supply high-tensile beams between and long for the Gladesville Bridge over the Paramatta River in New South Wales (just upstream from Sydney Harbour Bridge. It was the first time that beams of that length had been rolled in that type of steel. By the 21st century, the beam mill was the only plant in the United Kingdom capable of producing large steel sections for the building and construction industry.
The merger of British Steel and Hoogovens to form Corus was completed by 1999, and in the first year of operation, the Teesside Cast Products (TCP) business lost money, so a restructuring programme was initiated, but this did not include the TBM, and management of the mill was aligned away from TCP under the Scunthorpe operations. By the early 2000s, the plant was taking semi-finished steel from either the Teesside or Scunthorpe Steelworks, melting it at a temperature of , to make I-beams (girders) for the construction industry. Ingots ranging in weight from are brought to temperature and rolled in a primary mill, these are then sent to a roughing and finishing mill, before being hot sawn to the customers required length, and then coolled. Since the closure of the adjacent Teesside Steelworks at Redcar, the Scunthorpe plant some to the south has sent semi-finished steel to TBM via train, though some slab deliveries from Scunthorpe had started in the early 2000s.
The plant produced of girders in 1960, in 1969 and 1977, in 1989, and in 2006. In 2023 the plant had around 400 people working there. A new reheat furnace was built at the plant between 1984 and 1985, costing £17 million (), and the whole plant was modernised in the late 1980s at a cost of £69 million (), and a new high technology mill was completed in the summer of 1991. The new process in the mill reduced lead-in time for the creation of new beams from 18 hours to three hours.
Notable uses of TBM steel
Canary Wharf (London)
Catterick Bypass (A1 road)
Gladesville Bridge
Heathrow Terminal 5
London Stadium
The Scalpel, a skyscraper in London
The Shard
World Trade Center
Owners
Dorman Long 1958–1967
British Steel 1967–1999 (British Steel was privatised in 1988)
Corus 1999–2007
Tata Steel Europe 2007–2016
British Steel (Greybull Capital) 2016–2019
British Steel (Jingye) 2019–
Future
British Steel have put forward a proposal to take green hydrogen to power the plant instead of natural gas. This is projected to commence in 2024, with the hydrogen being produced nearby on Teesside. The TBM plant requires an energy consumption of per of steel rolled, which needs of natural gas, releasing of carbon into the atomosphere.
The owners of the Teesside Beam Mill, British Steel, announced in November 2023 their intention to stop making primary steel using the basic oxygen process at their Scunthorpe plant, and instead to utilise two Electric arc furnaces (EAF) to produce semi-finished steel from scrap metal. One of these EAF plants would be built adjacent to Teesside Beam Mill and would be used to supply the feedstock metal for the TBM and another British Steel plant at Skinningrove. This would mean the closure of the Scunthorpe plant with the loss of 2,000 jobs, and the cessation of semi-finished steel from Lincolnshire through to Teesside on freight trains, as the primary metal for the beam mill would be sourced from the adjacent plant EAF located nearby. In April 2024, the EAF plant was given the go-ahead, with a view to being operational in 2025. The EAF plant is slated to be tall, and cover an area of .
Notes
References
Sources
External links
Teesside Beam Mill 60th anniversary video
Film of the Lackenby Dorman Long works in 1961 via the Yorkshire Film Archive
Buildings and structures in Redcar and Cleveland
Buildings and structures in North Yorkshire
Ironworks and steelworks in England | Teesside Beam Mill | [
"Chemistry"
] | 1,163 | [
"Metallurgical industry of the United Kingdom",
"Metallurgical industry by country"
] |
74,940,609 | https://en.wikipedia.org/wiki/Wolfe%20cycle | The Wolfe Cycle is a methanogenic pathway used by archaea; the archaeon takes H2 and CO2 and cycles them through a various intermediates to create methane. The Wolfe Cycle is modified in different orders and classes of archaea as per the resource availability and requirements for each species, but it retains the same basic pathway. The pathway begins with the reducing carbon dioxide to formylmethanofuran. The last step uses heterodisulfide reductase (Hdr) to reduce heterodisulfide into Coenzyme B and Coenzyme M using Fe4S4 clusters. Evidence suggests this last step goes hand-in-hand with the first step, and feeds back into it, creating a cycle. At various points in the Wolfe Cycle, intermediates that are formed are taken out of the cycle to be used in other metabolic processes. Since intermediates are being taken out at various points in the cycle, there is also a replenishing (anaplerotic) reaction that feeds into the Wolfe cycle, this is to regenerate necessary intermediates for the cycle to continue. Overall, including the replenishing reaction, the Wolfe Cycle has a total of nine steps. While Obligate CO2 reducing methanogens perform additional steps to reduce CO2 to CH3.
Discovery
In 1971, in a review published by Robert Stoner Wolfe, information regarding methanogenesis in M. bryantii was published. At the time, the only thing known about this process was that Coenzyme M was involved. In addition, methanogenesis was thought to follow a linear pathway. It was not until 1986 that the reduction of CO2 to CH4 was proposed to occur in a cycle when it was shown that Steps 8 and 1 are coupled.
Steps
The Wolfe Cycle follows multiple pathways, depending on the microbe. Below are generalized steps in the Wolfe Cycle.
References
Anaerobic digestion
Archaea biology
Metabolic pathways | Wolfe cycle | [
"Chemistry",
"Engineering",
"Biology"
] | 401 | [
"Archaea",
"Metabolic pathways",
"Archaea biology",
"Anaerobic digestion",
"Environmental engineering",
"Water technology",
"Metabolism"
] |
74,940,655 | https://en.wikipedia.org/wiki/BubbleUPnP | BubbleUPnP is a DLNA-compliant UPnP media controller, server and renderer, designed to allow streaming of audio or video from and to an Android device with various external devices and software. Alongside the Android client, it also has a server middleware application that can be installed on Windows, macOS and Linux computers or network storage devices, providing remote access through a web interface. BubbleUPnP also utilises ffmpeg and ffprobe for transcoding.
Features
The app has three menus: Library (browsing media files locally or another server), Playlist (enqueuing files/folders), and Now Playing (controls the active media playback).
Server and controller
BubbleUPnP's integrated DLNA media server allows browsing of media of the Android device from other DLNA devices. The integrated renderer makes BubbleUPnP act as a control point on a home network between a source server and the player. According to the software website, it is able to play media to various external devices such as:
Smart TVs that have DLNA as well as DLNA-browsing devices such as PlayStation 3 or Roku, as well as Xbox
UPnP/DLNA/OpenHome music streamers from stereos/HiFis
Chromecast devices, Amazon Fire TV, Nexus Player
PC/NAS running a software like Kodi or JRiver Media Center, plus Raspberry Pi
There is also transcoding support for Chromecast devices and UPnP/DLNA music streamers.
Renderer
BubbleUPnP can play media from the local device itself, standalone UPnP/DLNA media servers (such as Kodi and Jellyfin) or those running on a NAS (including Synology, Western Digital and QNAP), local network SMB server shares (Windows and Mac), cloud storage services (such as Dropbox), WebDAV servers, and various third-party Android media and music apps. There is support for Internet radio streams like Shoutcast, which can be added in the Playlist menu by entering the URL of the stream.
Licensed version
BubbleUPnP is free to use and ad-supported; a number of advanced features are offered when purchasing a license, such as filesystem browsing from remote devices, unlimited playlist size, remote access to home libraries and no ads.
BubbleUPnP Server
BubbleUPnP Server is a server application to run on a PC or NAS on top of existing UPnP/DLNA devices. It allows the transcoding of media formats to be playable on a Chromecast if they are not natively supported, such as Xvid, AVI and FLAC. The server also provides secure remote access to existing media servers content from the BubbleUPnP app on Android, and from foobar2000 (with foo_upnp plugin) on Windows. Streaming or downloading of media from a mobile or Wi-Fi connection is also permitted, removing the need of synchronisation or online services.
See also
List of UPnP AV media servers and clients
References
External links
Official website
Media servers
Multimedia software
2011 software
Audio streaming software for Linux
Streaming software
Android (operating system) software | BubbleUPnP | [
"Technology"
] | 648 | [
"Multimedia",
"Multimedia software"
] |
74,941,123 | https://en.wikipedia.org/wiki/Tecno%20Phantom%20V%20Flip | Tecno Phantom V Flip is an Android-based smartphone manufactured, released and marketed by Tecno Mobile as part of the phantom sub-brand. The device was unveiled during an event held in Lagos, Nigeria on 27 September 2023.
Design
The two rear panels of the Phantom V Flip are covered in vegan leather, and the frame is made of aluminum. The hinge of the device is made of steel, while the internal screen has a thin plastic film and a plastic bezel around it. The foldable screen is covered by a thin film, and the panel has a small punch hole for the front camera. The dual-LED front flashes of the device are embedded in the top plastic bezel, next to the earpiece.
Specifications
Hardware
Chipsets
The device utilize the MediaTek Dimensity 8050 system-on-chip.
Display
The device features an AMOLED display with Full HD+ support and a display size of 6.9-inches. It utilizes a side-mounted fingerprint sensor and supports a 120Hz refresh rate. It features 1080 × 2640 resolution with a 22:9 aspect ratio and a 1.32-in cover screen.
Storage
The device offers 8 GB of LPDDR4X RAM with 256 GB of UFS 3.1 internal storage.
Battery
The device contains a non-removable 4000 mAh Li-Po battery, supporting wired charging over USB-C at up to 45W.
Connectivity
The phone supports the 5G network, Wi-Fi 802.11 and Bluetooth 5.1.
Cameras
The phone's rear camera features a 64 MP wide sensor, a 13 MP ultrawide sensor, and a 32 MP front camera.
Supported video modes
The Phantom V Flip supports the following video modes:
4K@30fps
1080p@30/60fps
Software
The device run on Android 13 based software overlay HiOS 13.5 at launch, and come bundled with a slew of apps like memory anti-aging, memory slimming, EllaGPT and lighting multi-window among others.
Reception
GSMArena awarded the phone 4.0 stars out of 5, noting that "the Tecno Phantom V Flip is an affordable foldable smartphone with a ton of premium features across the board". Praise was directed towards its leather design, both screens, performance, camera and processor. However, the lack of ingress protection, HDR10 support and EIS for 4K videos was criticized, while noting that "the Phantom V Flip may not be a perfect phone, but it does come at a perfect price".
Harish Jonnalagadda from Android Central gave the Phantom V Flip a score of 3.8/5 and stated that "the foldable has a striking design with a unique camera island that houses the cover screen, and the build quality is on par with its rivals". He, however, criticized the cameras and noted they "are strictly average" while adding that the "software lacks polish".
Hadley Simons from Android Authority gave the Phantom V Flip a score of 6/10, describing the performance as solid and praising the selfie camera flash, design, and battery. However, he criticized the device for lack of IP rating and noted that the ultrawide camera is disappointing.
Duey Guison from Unbox noted that "Tecno made a bold statement with the Phantom V Flip with its competitive pricing for a flip foldable".
References
Android (operating system) devices
Flip phones
Mobile phones with 4K video recording
Foldable smartphones
Mobile phones introduced in 2023
Tecno smartphones | Tecno Phantom V Flip | [
"Technology"
] | 733 | [
"Crossover devices",
"Foldable smartphones"
] |
74,941,164 | https://en.wikipedia.org/wiki/Phaeotremella%20mycophaga | Phaeotremella mycophaga is a species of fungus in the family Phaeotremellaceae. It produces small, pustular, gelatinous basidiocarps (fruit bodies) on the hymenium of the corticioid fungi Aleurodiscus amorphus and A. grantii on conifers.
Description
Fruit bodies are gelatinous, hyaline to pinkish, up to 1.5 mm (0.05 in) across, and disc-like to pustular, sometimes coalescing Microscopically, the hyphae are clamped and occur in a dense gelatinous matrix. The basidia are tremelloid (globose, with vertical septa), 13 to 15 μm across. The basidiospores are globose, smooth, 6.5 to 8.0 μm across.
Similar species
Phaeotremella simplex occurs on the same hosts and is indistinguishable in the field, but lacks clamp connections. Phaeotremella mycetophiloides is also similar, but was originally described from Japan. It may represent an earlier name for P. mycophaga.
Habitat and distribution
Phaeotremella mycophaga parasitizes the corticioid fungi Aleurodiscus amorphus and A. grantii, both of which occur on dead attached wood of conifers. The species was originally described from Canada, but has been found elsewhere in North America and in continental Europe.
References
Tremellomycetes
Fungi described in 1940
Fungi of North America
Fungi of Europe
Fungus species | Phaeotremella mycophaga | [
"Biology"
] | 339 | [
"Fungi",
"Fungus species"
] |
77,902,247 | https://en.wikipedia.org/wiki/SDSS%20J135646.10%2B102609.0 | SDSS J135646.10+102609.0 known as SDSS J1356+1026 and J1356+1026, is a low redshift quasar and galaxy merger located in the constellation of Boötes. It is located 1.85 billion light years from Earth. It is an ultraluminous inflared galaxy. It is considered radio-quiet with an unresolved radio source.
Characteristics
SDSS J135646.10+102609.0 is a merger product between two colliding galaxies, namely a disk galaxy and an elliptical galaxy. The galaxy has a luminosity of Lbol ≈ 1046 erg s−1 with an estimated black hole mass of M ~ 108 MΘ.
SDSS J135646.10+102609.0 has two active nuclei found merging, with a projected separation of only 2.4 or ~ 2.5 kiloparsecs. While nothing is known about the south nucleus, the north nucleus is classified a type 2 quasar and is the main galaxy merger member. Its host is a massive early-type galaxy or an ETG for short, with a position angle of 156 degrees. With a stellar population mainly made up of old stars, the star formation rate of the galaxy derived from infrared luminosity is 69 MΘ yr−1 according to a Atacama Large Millimeter Array (ALMA) sample. This high star formation rate indicates a consequence of an ongoing merger.
The north nucleus is heavily obscured. It was originally found during the Sloan Digital Sky Survey based on its [ O III] λ5007 emission. The north nucleus also has an average velocity dispersion value of 160 km s−1. According to B-I color map of the galaxy using HST/WFC 3 images, astronomers found a dust lane crossing its nucleus with its position angle matching with the oxocarbon major axis. Using spatial scales, they were able to find the north nucleus has redder optical colors.
In addition, the north nucleus contains a compact rotating disk and an extended tidal arm. Both components contain molecular gas mass of Mmol ≈ 3 x 108 MΘ and Mmol ≈ 5 x 108 MΘ. Further investigations from ALMA also pointed out the tidal arm is the largest molecular tidal feature, implying a small chance of shock dissociation.
Further investigations also shows the presence of soft X-ray emission around the quasar nucleus of SDSS J135646.10+102609.0, extending by 20 kiloparsecs (kpc). This is interpreted as thermal gas with a luminosity of LX ≈ 1042 erg s−1 and temperature of KT ≈ 280 eV. With a faint X-ray luminosity of ~ 10, this suggests the X-ray emission is controlled by either photoionization or shocked emission via a quasar-driven superwind. A study also mentions the superwind driven by the quasar is prototypical.
Galactic outflow
SDSS J135646.10+102609.0 has two symmetric outflows originating from its nucleus. The outflows are measured to be 10 kpc and have observed projected expansion velocities of 250 km s−1. Through a presentation of a kinetic model, the deprojected expansion velocity for this outflows are measured ~ 1000 km−1 with expanding shell kinetic energy of 1044-45 erg s−1.
Star formation
Based on observations from ALMA and oxocarbon observations, a low star formation rate of 16 MΘ yr−1 from far-infrared spectral energy and <16 MΘ yr−1 from the molecular content is found in SDSS J135646.10+102609.0. This suggests the active galactic nucleus of the galaxy is likely responsible for high outflow rate. With an outflowing mass of Mmol ≈ 7 x 107 MΘ, and short dynamical time, the outflow could potentially depleting the gas content inside SDSS J135646.10+102609.0 within few million years.
Double-peaked emission lines
SDSS J135646.10+102609.0 is known to be an interesting system. According to long-slit observations, it contains two [O III] λ5007 emission knots proportional to the two nuclei seen in near-infrared imaging suggesting the double peaks are produced by a dual AGN. However when the extended [O III] emission and nuclei were observed again, this creates a speculation the double peaks are only powered by a single AGN.
References
SDSS objects
Luminous infrared galaxies
1379498
Quasars
F13543+1040
Boötes
Galaxy mergers | SDSS J135646.10+102609.0 | [
"Astronomy"
] | 970 | [
"Boötes",
"Constellations"
] |
77,903,251 | https://en.wikipedia.org/wiki/Hypnea%20cervicornis | Hypnea cervicornis is a species of marine red algae found in warm waters worldwide.
References
Red algae species
Species described in 1851
Gigartinales | Hypnea cervicornis | [
"Biology"
] | 35 | [
"Algae stubs",
"Algae"
] |
77,903,311 | https://en.wikipedia.org/wiki/Blindsight%20%28Neuralink%29 | Blindsight is an experimental medical device developed by Neuralink. It has received Breakthrough Device Designation from the US Food and Drugs Administration (FDA).
Purpose
Blindsight is being developed to enable individuals with total visual impairment due to damage to the optic nerve but with intact visual cortex to see, this is made possible by bypassing the optic nerve and directly stimulating the visual cortex to create a visual perception.
References
Medical devices
Blindness_equipment | Blindsight (Neuralink) | [
"Biology"
] | 87 | [
"Medical devices",
"Medical technology"
] |
77,903,754 | https://en.wikipedia.org/wiki/Ammonium%20hexacyanoferrate%28II%29 | Ammonium hexacyanoferrate(II) is an inorganic chemical compound with the chemical formula .
Synthesis
Neutralization of ferruginous acid with ammonia solution followed by salting with ethanol:
Physical properties
Ammonium hexacyanoferrate(II) forms green crystals.
The compound is well-soluble in water, and does not dissolve in ethanol.
It forms hydrates.
References
Cyano complexes
Ammonium compounds
Cyanometallates
Ferrates | Ammonium hexacyanoferrate(II) | [
"Chemistry"
] | 96 | [
"Ferrates",
"Ammonium compounds",
"Salts"
] |
77,903,762 | https://en.wikipedia.org/wiki/IRAS%2013349%2B2438 | IRAS 13349+2438 is a Seyfert galaxy located in the constellation of Boötes. It is located 1.45 billion light-years from Earth and a prototype infrared-luminous low-redshift quasar with a projected luminosity of 2 x1046 erg s−1 according to Beichman who discovered it in 1986.
IRAS 13349+2438 has a spiral-like appearance according to digital imaging made on the galaxy's host and the nearby environment. It has a companion galaxy, suggesting the galaxy might have interacted with it, given the evidence of tidal structures. It is likely the interaction has given rise to its quasar activity as interstellar dust and gas are supplied to the galaxy's nucleus. Additionally, IRAS 13349+2438 shows increasing high optical polarization at declining wavebands. It is a radio-quiet quasar despite weak radio emission being reported at 6 GHz.
The galaxy has strong properties of Fe II emission and weak [O III] that is relative to Hβ. A study made by Chandra X-ray spectrum with the HETGS grating spectrometer, also confirms IRAS 13349+2438 has a rich absorption spectra of quasar outflows. It is also said the object contains a double-peaked absorption measure distribution whom researchers finds the object has an ionized column density of NH = (1.2 ± 0.3) x 1022 cm−2.
IRAS 13349+2438 has been observed by the XMM Newton Observatory on a few occasions. In 2000, XMM Newton discovered that the galaxy contains several broad absorption lines from various ionized elements like nitrogen, oxygen and iron L-shell ions. Further evidence shows, IRAS 13349+2438 also has an unresolved transitional array of an inner-shell absorption, possibly misidentified to be an OVII edge through observations made by moderate resolution spectrometers. In 2018, IRAS 13349+2438 was observed again, which it contains large numbers of absorption lines originating from warm absorption zones with measured velocities of ~-600 km s−1. A joint study by NuSTAR and XMM Newton confirms presence of iron absorption lines at both 8 and 9 keV, with velocities of 0.14c and 0.27c. Based on findings, IRAS 13349+2438 shows possible detections of multiphase ultra-fast outflows.
In a study sample of narrow-line Seyfert galaxies, IRAS 13349+2438 contains an unresolved core region with an approximate size of 540 x 235 parsecs. It has a high brightness temperature of ~72,000 K, indicating the galaxy has a low-power relativistic beamed jet. Furthermore, it has an average star formation rate over 100 Myr of 105.8 ± 29.5 MΘ yr−1 and mass of 21.44 ± 2.68 1010 MΘ.
References
IRAS catalogue objects
Boötes
101275
Seyfert galaxies
Quasars
Astronomical objects discovered in 1986 | IRAS 13349+2438 | [
"Astronomy"
] | 643 | [
"Boötes",
"Constellations"
] |
77,904,222 | https://en.wikipedia.org/wiki/Urban%20area%20of%20Vietnam | Urban areas in Vietnam include cities, district-level town, and commune-level town officially recognized by state authorities of Vietnam. While districts and communes are generally rural, some may be classified as urban if they meet certain conditions. Communes set to be upgraded to towns can also be recognized as type V urban areas.
Vietnam's cities are classified into six types: special, type I to type V. Special, type I, and type II cities are approved by the prime minister; type III and IV cities by the Ministry of Construction; and type V by the provincial government. The classification process is overseen by the National Assembly's Standing Committee.
Types of urban areas
As of August 16, 2024, there are 908 recognized urban areas in Vietnam
, classified as follows:
Special: 2 (Hanoi and Ho Chi Minh City)
Type I: 21
Type II: 39
Type III: 43
Type IV: 97
Type V: 706
Criteria for classification
The classification of urban areas in Vietnam is based on a series of factors, including population, density, and the proportion of non-agricultural labor. The classification framework is outlined in Resolution No. 1210/2016, which provides the following criteria for each type of urban area:
Currently, Vietnam has two cities classified as special urban areas by the government: Hanoi and Ho Chi Minh City. To support the authorities of these two cities in fulfilling their functions as special urban areas, the government allows Hanoi and Ho Chi Minh City to benefit from certain specific financial and budgetary mechanisms.
Urban areas in special regions
In special cases, such as border areas or island regions, urban classification criteria are relaxed. These areas may have lower population and density thresholds but must still meet the majority of the other standards set for their respective classification. For example:
Mountainous and border regions: May have lower population density, but must meet at least 70% of the required standards.
Islands: Must meet 50% of the infrastructure and architectural standards, while population and socio-economic standards are reduced to 30%.
See also
List of cities in Vietnam
District-level town
Commune-level town
References
External links
Resolution No. 1210/2016/UBTVQH13 of the Standing Committee of the National Assembly on Urban Classification (in Vietnamese)
Urban planning
Vietnam geography-related lists | Urban area of Vietnam | [
"Engineering"
] | 461 | [
"Urban planning",
"Architecture"
] |
77,905,894 | https://en.wikipedia.org/wiki/OB-fold | In molecular biology, the OB-fold (oligonucleotide/oligosaccharide-binding fold) is a small protein structural motif observed in different proteins that bind oligonucleotides or oligosaccharides. It was originally identified in 1993 in four unrelated proteins: staphylococcal nuclease, anticodon binding domain of aspartyl-tRNA synthetase, and the B-subunits of heat-labile enterotoxin and verotoxin-1. Since then it has been found in multiple proteins many of which are involved in genome stability. This fold is often described as a Greek key motif.
Structure
The OB-fold consists of a five-stranded β-sheet coiled to form a closed β-barrel, capped by an α-helix located at one end and a binding cleft at the other. The α-helix packs against the bottom layer of residues, roughly perpendicular to the barrel axis. The β-sheet structure protrudes beyond this layer and packs around the sides of the helix. The binding specificities of each OB-fold depend on the different length, sequence, and conformation of the loops connecting the β-strands.
Structural determinants
OB-fold domains have several key structural determinants. These common features arise from physical principles governing protein structure rather than from sequence homology.
β-sheet structure:
The closed β-sheet has specific parameters that determine geometrical features like mean radius and average angle between strand directions and barrel axis.
β-bulges:
Most structures have a common β-bulge in the first strand. β-bulges provide small increases in barrel radius and required coiling of β-strands.
Interior residue packing:
The interior of the closed β-sheet has a regular three-layer structure of residues, with each β-strand contributing one residue to each layer.
β-barrel deformation:
Many β-barrels are similarly flattened, with an elliptical cross-section.
Barrel-helix interface:
A cavity on the barrel axis is filled by a large hydrophobic residue from the helix.
Binding site location:
In some proteins, the binding sites are located on the side surface of the β-barrel where three loops come together, in such a way they are partially wrapped by the binding partner. In others, the binding cleft at the side of the barrel opposite to the helix functions as binding site.
Function
OB-folds are versatile binding domains that can interact with single-stranded DNA (ssDNA), double-stranded DNA (dsDNA), RNA, proteins, phospholipids and oligosaccharides. In genome guardian proteins, OB-folds play crucial roles in DNA binding and recognition, protein-protein interactions and catalytic functions in multi-subunit complexes.
Examples of proteins containing this domain
Single-stranded DNA binding protein (SSB)
Replication Protein A (RPA)
RecG helicase
RuvA (part of the Holliday junction branch migration complex)
Minichromosome maintenance (MCM) proteins
DNA ligase III
RecO (recombination mediator)
Relationship to SH3 domains
OB-folds are structurally similar to Src homology 3 (SH3) domains, with their β-strands superimposing with less than 2 Å difference. This structural similarity is important for understanding OB-fold function and regulation, as SH3 domains bind to PXXP-containing ligands in a pocket similar to the ssDNA binding pocket of many OB-folds.
Evolution and distribution
The OB-fold may represent a stable folding motif that appeared early in protein evolution, with its wide occurrence due to its adaptability to different functions and sequences. OB-fold proteins present great versatility, which likely contributed to the development and widespread adoption of the fold in genome guardian proteins. They can adopt various oligomerisation states and quaternary structures, allowing for complex and dynamic interactions. The OB-fold has flexibility in binding to a variety of substrates through variations in loop sizes, compositions, and insertions, showing a modular nature. In some cases, it can provide catalytic functions to multi-subunit complexes, expanding its utility beyond just binding. Its structural similarity to SH3 domains allows OB-folds to participate in protein-protein interactions, enabling regulation and complex formation.
References
External links
InterPro: Nucleic acid-binding, OB-fold (IPR012340)
Protein domains
Protein folds
Protein superfamilies | OB-fold | [
"Biology"
] | 911 | [
"Protein superfamilies",
"Protein domains",
"Protein classification"
] |
77,906,123 | https://en.wikipedia.org/wiki/Political%20representation%20of%20nature | Political representation of nature refers to the concept and practice of granting political, or institutional standing to nonhuman entities—such as animals, plants, and ecosystems—within governance systems. This concept has developed to incorporate natural entities in political decision-making, reflecting debates about human-centered governance's effectiveness in environmental protection.
The debate in this field is driven by emerging trends, including the political turn in environmental ethics and the representative turn in political theory. Following progress in legal representation for nonhuman nature, such as the granting of legal personhood to animals, rivers and ecosystems, the conversation has broadened to consider how nature can be represented within legislative and executive branches of government.
Historical and theoretical background
Historically, early thinkers, including Thomas Hobbes, framed nature as passive and separate from human society. Later, theorists such as Bruno Latour introduced concepts, such as a 'parliament of things,' proposing that democratic processes consider nonhuman actors. Latour’s approach has been cited as influential in political theories addressing ecological issues, emphasizing the interconnectedness of human and environmental systems.
Since the early 2000s, frameworks such as Earth Jurisprudence and Rights of Nature have further influenced the concept of nonhuman representation. These frameworks propose that nature has intrinsic value deserving of rights both legally and morally. The works of political theorists like Andrew Dobson, Robyn Eckersley, Robert Goodin, and John O'Neill have contributed to this shift. They propose that humans have an ethical responsibility toward nature, suggesting that democratic systems might evolve to account for nonhuman interests.
Institutional mechanisms
Various institutional mechanisms have been proposed and put into practice to incorporate nonhuman entities and ecosystems into formal political decision-making processes.
Electoral reforms like proportional representation and lowering electoral thresholds have been suggested to facilitate the entry of green parties into parliaments. These changes could help increase the political influence of parties dedicated to environmental advocacy, further amplifying the representation of nature in governance.
Deliberative initiatives, such as citizen assemblies and deliberative mini-publics, engage randomly selected citizens in structured discussions on environmental issues, providing a platform for nonhuman interests to be included in political discourse. While these bodies typically do not have formal decision-making power, they can influence policy indirectly by informing legislators.
Dedicated ombudspersons or commissioners are independent offices that investigate and advocate for the rights of natural entities, operating similarly to human rights commissioners.
The allocation of seats in existing parliaments to specific representatives of nature mirrors systems of political reservations used to ensure representation for marginalised human groups. These nature representatives would advocate for the interests of ecosystems and nonhuman entities within legislative bodies.
On a global level, the establishment of new supranational institutions has been proposed. Suggested frameworks include regional ecosystem assemblies for different biomes and an Earth System Council to coordinate global environmental action. Both institutions aim to include representation from states, indigenous communities, and proxy guardians for the non-human.
Political representation of nature in practice
Examples of nonhuman representation exist in several countries.
In New Zealand, the Parliamentary Commissioner for the Environment is responsible for monitoring environmental issues. This office conducts investigations, reviews, and reports on environmental conditions and evaluates the effectiveness of government policies. Its role is intended to support transparency and accountability in environmental governance.
The European Commissioner for Health and Animal Welfare is responsible for updating animal welfare regulations within the European Union. The position also promotes the One Health approach, which recognizes the interdependence of people, animals, plants, and their shared environment.
In Wales, the Future Generations Commissioner ensures that the interests of future generations are considered in policy-making. The office evaluates the long-term impacts of current policies and promotes sustainable development practices aimed at safeguarding both human and environmental health.
In Germany, the Federal Animal Welfare Officer provides oversight on animal welfare matters and advises the federal government across sectors such as agriculture, research, and industry.
Australia’s Inspector-General of Animal Welfare and Live Animal Exports advises the federal government on issues related to animal welfare and oversees the development of policies to improve the treatment and protection of animals.
In Spain, the General Director of Animal Rights manages animal welfare policies at the federal level, developing strategies to enhance animal rights and incorporating these into broader social and legislative frameworks.
The Commissioner for Animal Welfare in Malta enforces animal welfare laws and oversees the proper treatment of animals, ensuring compliance with national regulations.
In New York City, the Office of Animal Welfare focuses on policies related to the health, safety, and welfare of wild animals and pets.
See also
Rights of nature
Environmental ethics
Environmental justice
Environmental crime
Environmental personhood
Human impact on the environment
References
Environmental ethics
Environmental social science concepts
Environmental justice | Political representation of nature | [
"Environmental_science"
] | 952 | [
"Environmental social science concepts",
"Environmental social science",
"Environmental ethics"
] |
77,907,374 | https://en.wikipedia.org/wiki/Levinsonite-%28Y%29 | Levinsonite-(Y) is a rare organic mineral named in honor of Alfred A. Levinson (1927-2005), professor of mineralogy at the University of Calgary. It was named in part because of his origination of the internationally used nomenclature for rare-earth minerals, the Levinson modifier, which is a standard in mineralogical nomenclature and allows for the more precise identification and classification of rare-earth minerals.
The type material for Levinsonite-(Y) is kept at the University of Michigan, and the Smithsonian National Museum of Natural History in Washington, D.C.
Discovery
In 1981, T. Dennis Coskren and Robert J. Lauf began investigating a large number of unusual minerals at the Alum Cave Bluff (ACB), Great Smoky Mountains National Park, Tennessee, USA. Coskren and Lauf discovered three new rare-earth element minerals, which have subsequently been named coskrenite-(Ce), levinsonite-(Y), and zugshunstite-(Ce). After submission to the International Mineralogical Association (IMA), the naming of Levinsonite-(Y) was approved by the Commission on New Minerals and Mineral Names and given the IMA number 1996-057.
References
Organic minerals | Levinsonite-(Y) | [
"Chemistry"
] | 264 | [
"Organic compounds",
"Organic minerals"
] |
77,908,009 | https://en.wikipedia.org/wiki/Basquin%27s%20law | Basquin's law of fatigue states that the lifetime of the system has a power-law dependence on the external load amplitude, , where the exponent has a strong material dependence. It is useful in expressing S-N relationships.
It is a fundamental principle in materials science that describes the relationship between the stress amplitude experienced by a material and its fatigue life under cyclic loading conditions. The law is named after American scientist O. H. Basquin, who introduced the law in 1910. The law provides a mathematical model to predict the number of cycles to failure (N) based on the applied stress amplitude .
A High Cycle Fatigue Test is used to determine material behaviour under repetitive cyclic loads. This test aims to establish the stress-cycles-to-failure characteristics of materials, primarily utilising an identified stress range and load application frequency. It is usually performed using a standard fatigue testing machine where the test specimen is prepared in a specifically defined manner and then subjected to loads until failure takes place. Throughout the test, computer software is used to record various necessary parameters such as the number of cycles experienced and the exact point of failure. This testing protocol enables the development of an S-N curve (also known as a Wöhler curve), a graphical representation of stress amplitude (S) versus the number of cycles to failure (N). By plotting these curves for different materials, engineers can compare them and make informed decisions on the optimal material selection for specific engineering applications. The S-N relationship can generally be expressed by the Basquin's law of fatigue, which is given by:
,
where is the stress amplitude, is the fatigue strength coefficient, is the number of cycles to failure, is the fatigue ductility coefficient, and is the fatigue strength exponent. Both and are properties of the material.
Basquin's Law can also be expressed as , where is the change in stress, is the number of cycles to failure, and both and are constants.
References
External links
ADVANCED STATISTICAL EVALUATION OF FATIGUE DATA OBTAINED DURING THE MEASUREMENT OF CONCRETE MIXTURES WITH VARIOUS WATER-CEMENT RATIO
Fatigue - ETH Zürich
Mathematical modeling
Materials science | Basquin's law | [
"Physics",
"Materials_science",
"Mathematics",
"Engineering"
] | 428 | [
"Mathematical modeling",
"Applied and interdisciplinary physics",
"Applied mathematics",
"Materials science",
"nan"
] |
77,908,584 | https://en.wikipedia.org/wiki/USED%20Chinook | The steamship Mohawk was steel-hulled freighter built for the Atlantic Transport Line in 1892. She carried live cattle and frozen beef from the United States to England until the advent of the Spanish–American War. In 1898 she was purchased by the United States Army for use as an ocean-going troopship. During the Spanish–American War she carried troops and supplies between the U.S. mainland, Cuba, and Puerto Rico.
After the war, she was renamed USAT Grant and refit for service as a troopship in the Pacific. She carried troops and supplies to the Philippines and China to support the Army in the Philippine Insurrection and the Boxer Rebellion. Costly boiler repairs and the need to reduce the size of the Army Transport Service's Pacific fleet led to the ship's retirement as a troopship in 1902.
Grant was transferred to the United States Army Corps of Engineers and converted into a suction dredge in 1903. At that time she was the largest such dredge in the world and remained so until 1938. Grant was renamed USED Chinook. She was responsible for widening and deepening shipping channels on the Columbia, Delaware, and Mississippi rivers, Hampton Roads, Tampa Bay, New York Harbor, and other major ports and waterways. She was decommissioned in 1946 and subsequently scrapped.
Construction and characteristics
The Atlantic Transport Line commissioned four sister ships to be built by the Harland & Wolff shipyard in Belfast, Ireland. They were, in order of launch, Massachusetts, Manitoba, Mohawk, and Mobile.
Mohawks hull was built of steel plates. She was long, with a beam of and a depth of hold of . Her gross register tonnage was 5,658, and her net register tonnage was 3,646.
She was driven by two propellers. These were turned by two triple-expansion steam engines which were also built by Harland & Wolff. They had high, medium, and low-pressure cylinders with diameters of 22.5 inches, 36.5 inches, and 60 inches, respectively, with a stroke of 48 inches. Each of the engines was rated at . Steam was provided by coal-fired boilers. At full speed, the ship would burn 60 tons of coal a day.
Mohawks cargo capacity was built primarily to support the shipment of American beef to England, both in the form of live cattle and refrigerated dressed beef. She was fitted out to transport 1,000 live cattle, with a space of long by wide allocated to each animal. Her refrigerated holds could carry 1,000 tons of fresh meat. The ship also had accommodations for up to sixty cabin passengers.
Mohawk was launched from the Harland & Wolff shipyard on Queen's Island on 25 February 1892. Her engines and machinery were then installed and she was delivered to her new owners on 7 May 1892.
Atlantic Transport Line (1892–1898)
While the Atlantic Transport Line was controlled by American shipping magnate Bernard N. Baker, its operations were run from Britain. Mohawks home port was London and she was registered as a British ship. During her six-year career with Atlantic Transport Line she was assigned to the New York to London route.
Mohawk proved exceptionally capable at moving cattle across the Atlantic. On her first crossing in 1892, she brought 489 cattle to England and only two died en route. Since horses could be shipped using the same facilities as cattle, Mohawk occasionally shipped them as well. In 1897 the hunter Long Shot was shipped to England as a gift to the Duchess of Marlborough from her mother. On the same trip, Mohawk carried 206 horses purchased for British cavalry use. Noted race horse enthusiast Pierre Lorillard shipped a dozen thoroughbreds to London on board. In 1892 Mohawk carried Buffalo Bill's Wild West Show from London back to America. Among the livestock that accompanied the show aboard were 18 buffalo, 9 kicking broncos, and 3 of Cody's personal horses.
Mohawk was a speedy ship for her day. In August 1892 she reached New York From London in 9 days, 20 hours, the fastest passage to that time by a freighter. She beat the record of her sister ship, Manitoba.
Perhaps the most eventful day of Mohawks career as a commercial vessel was 20 January 1897 when she saved the 17 surviving crew of the dismasted and sinking Norwegian bark Persia during a North Atlantic storm.
Army Transport Service (1898–1902)
Spanish–American War (1898)
On 25 April 1898, Congress declared war on Spain, beginning the Spanish–American War. An immediate objective was to defeat Spain in the Caribbean, taking Cuba and Puerto Rico. At the time, the United States had few overseas possessions, and thus its military had limited ocean-capable sealift to support such an offensive. American political leaders preferred to acquire American ships to support the war effort, rather than enrich foreigners and rely on foreign crews. There were also legal constraints on using neutral-flagged vessels in American military operations. Through some quirks in the Congressional funding of the war, the United States Navy was able to charter transport ships prior to the declaration of war and tied-up the best of the American merchant fleet for its use. When the United States Army was able to begin acquiring ships after the declaration of war, fewer domestic options remained. While the Atlantic Transport Line was British-flagged, it was American owned, making it a more attractive option.
Army Colonel Frank J. Hecker approached the Atlantic Transport Line to charter its fleet, and was refused. He then offered to buy the vessels he sought and a deal was struck, subject to the approval of the Secretary of War Russell Alger. In addition to Mohawk, the Atlantic Transport Line sold Massachusetts, Manitoba, Mobile, Michigan, Mississippi, and Minnewaska. These ships were placed under the Quartermaster's Department of the United States Army. The Army reckoned Mohawks capacity to be 80 officers, 1,000 men, and 1,000 horses. Mohawk was turned over to the Army in New York on 29 June 1898. The price of the ship was $660,000.
The Army immediately sent the ship into dry dock to have the marine growth scraped from her bottom. The British crew of 79 men refused to serve on a United States military ship. It was variously reported at the time that they were either replaced by Americans or agreed to serve with a 20 percent increase in their wages. However, she was crewed, the ship sailed from New York for Tampa on 5 July 1898, less than a week after the Army took possession. She carried approximately 600 mules, 200 horses, and 1,400 men from Tampa to Puerto Rico. By the time Mohawk reached the island on 2 August 1898, the fighting was all but over. Hostilities ceased on 12 August 1898.
Pacific service (1898–1902)
Having taken Cuba, Puerto Rico, Guam, and the Philippines, the Army had a permanent need for transport to overseas bases. The annexation of Hawaii in 1898 also required new ocean transport. The Army Transport Service chose the best vessels acquired during the war to become a permanent sealift capability. Mohawk and her three sister ships were retained for this purpose. To mark their transition to permanent military service, they were renamed in January 1899 for prominent Civil War generals. Mohawk became United States Army Transport Grant, named for Ulysses S. Grant.
On 27 September 1898, the ship arrived at the Bath Iron Works in Bath, Maine for modifications to prepare her for transport service in the Pacific. The shipyard was the low bidder for the job at $82,800. During the work, the Army requested a number of extras which raised the ultimate cost to about $135,000. Among the projects accomplished at Bath were fitting two lower decks with three-tier pipe-berths which could accommodate 2,170 troops, and expanding the galley, messing, shower, toilet, ventilation, and other facilities to support the troops. Over 100 painters were employed to completely repaint the ship in lead white. A 50-bed hospital was installed. She sailed to New York, after her refit was complete, where she arrived on 4 January 1899.
Grant was assigned to deliver troops to the Philippines via the Suez Canal. In New York she embarked the 4th Infantry Regiment and one battalion of the 17th Infantry Regiment. Also aboard were Major General Henry Lawton and his staff. In total there were 1,730 enlisted troops and about 150 officers and their families aboard. As Grant was the first major transport to leave New York for the Philippines, her departure was attended by a number of notable figures including Assistant Secretary of War Meiklejohn, Adjutant General Corbin, and Quartermaster General Ludington, U.S. Senators Proctor, Warren, and Mitchell, and seven U.S. Representatives, all members of the House Committee on Military Affairs.As Grant backed out of her berth to begin her voyage on 17 January 1899, her starboard propeller fouled an old wire hawser. She was towed to her anchorage and divers were able to clear the old cable. On 18 January 1899 the ship sailed up the Hudson River to Grant's Tomb where a short ceremony was held to honor her namesake. The next day Grant sailed for Gibraltar, where she arrived on 1 February 1899. After taking on coal and water, Grant sailed on, arriving in Suez on 12 February 1899, Colombo on 26 February 1899, Singapore on 4 March 1899, and finally Manila on 10 March 1899.
Grant sailed from Manila on 25 March 1899 for San Francisco, via a coaling stop in Nagasaki. She had on board the bodies of a number of soldiers killed in the Philippines as well as sick and wounded. She arrived on 29 April 1899. As the Philippine Insurrection grew, so did the urgency to move more troops to the islands. Grant and other Army Transport Service ships began a shuttle from San Francisco to Manila. On most of her trips to Manila, Grant carried complete troop units, and a number of recruits and replacements for units already in the Philippines. On her return trips, she usually carried soldiers who were wounded, ill, or dead, prisoners, and those whose enlistment had expired. Depending on the size of her human cargo, she would also board supplies. On one trip she carried almost 5,000 tons of supplies. The ship had a strong room and used it to carry cash to Manila to pay the Army's expenses. In October 1900, Grant sailed with $1.3 million aboard.
Among her cabin passengers were a number of notable figures. In July 1900, Grant sailed from San Francisco to Taku Bay, China with Major General Adna Chaffee, the commander of China Relief Expedition during the Boxer Rebellion. The civilian Governor of the Philippines, later U.S. President, William Howard Taft sailed home from Manila in December 1901 on Grant.
Grant received periodic safety inspections of her boilers throughout her service with the Army Transport Service. She failed her inspection in March 1902 and her next trip to Manila was cancelled. In May 1902, Grants crew was discharged as it became clear that significant repairs could not be avoided. The low bid on the repair work was $358,000. The need for these costly repairs arose at the same time the Army was reducing its Pacific transport fleet as fighting in the Philippines and China decreased. The Army decided to retire Grant rather than pay for repairs, and offered the ship for sale in a sealed bid process. When the bids were opened in July 1902, the high bid for the ship was $51,000. The Army did not accept this bid.
In September 1902, Secretary of War Elihu Root announced that Grant would be transferred to the U.S. Navy. While the Army Transport Service was struggling with the cost of its Pacific fleet, the Army Corps of Engineers was struggling to dredge the mouth of the Columbia River. There was substantial Congressional support for deepening the Columbia, with $500,000 appropriated in 1902 and $1,000,000 in 1903. The Engineers developed a plan to convert Grant into a dredge to assist the project. They argued that a conversion would be much cheaper than building a new ship, and that the waters at the mouth of the Columbia were so rough that only a large ship like Grant could do the work. The Navy was convinced to relinquish its claim, and Grant was transferred to the Army Corps of Engineers in October 1902.
Army Corps of Engineers (1903–1946)
Plans to convert Grant into a dredge were completed in November 1902. After a lengthy and contested bidding process, the contract for the conversion work was awarded to the Mare Island Naval Shipyard in February 1903. The work was completed in October 1903. The cost of the conversion was about $270,000. She was given a new name, United States Engineers Department Chinook. She was the largest dredge of her type in the world when completed, and remained so until 1938 when she was supplanted by USED Goethals.Chinook was a hopper dredge, or suction dredge. Much of her internal volume were two -deep hoppers, bins that could hold of sand. Underneath the hoppers were 16 gates that could be opened to discharge the sand. On each side of the ship was a drag arm, a steel pipe, that could be lowered to the bottom. The pipe was in diameter. At the end of each drag arm was a drag shoe which was covered by a grate to keep large items from being sucked up the drag arm.
When Chinook was dredging, her drag arms were lowered to the bottom. Powerful pumps sucked sand and gravel up through the drag arms and dumped it into the hoppers. In 1903 the ship was fitted with two centrifugal pumps that were capable of pumping of sand per hour. Each pump was powered by its own triple-expansion steam engine with high, medium, and low-pressure cylinders of 13, 20, and inches and a stroke of 20 inches. When the hoppers were full, Chinook would raise her drag arms, sail to a designated dumping ground, open the gates in the bottom of the hoppers, and let gravity discharge the dredging spoil into the water.
Chinook reached Astoria, Oregon, at the mouth of the Columbia, on 3 November 1903. She was not ready to begin operations, but completed some short test and training dredges with her new crew. Among the things that the testing revealed was that her boiler problems had not been fixed. Chinook went to the shipyard in Portland where 14 patches on the boilers were repaired in April 1904.
In May and June 1904, Chinook was finally able to begin dredging the Columbia Bar. In that two month period she dredged for 40 days, and removed of sand and gravel from the river at a cost of $0.143 per yard. In fiscal year 1905, Chinook removed an additional . Dredging was discontinued in April 1905 and the ship was laid up. Once again, the problem was that her boilers were unsafe and there was no money to fix them. The ship was idle for four years. Finally, plans were made to replace her four boilers and convert them from coal to oil-burning. During the same shipyard visit, tons of steel in her unneeded passenger cabins and superstructure were to be removed so as to give her a smaller draft, allowing her to work in shallower water. Bids for the work were opened on 22 December 1909 and the work completed on 25 August 1910. The cost of this refit was $137,075. Her new displacement was reported as 7,400 tons. Another shipyard visit in 1914 added two centrifugal pumps connected to drag arms 30 inches in diameter. These changes significantly improved dredging performance. By the end of the 1915 dredging season, Chinook was able to dredge in an eight-hour shift. She had two full crews aboard to extend her working days when the weather and seas allowed.
The Columbia Bar was too rough for dredging in the stormy winter months, so Chinook dredged from May to October. She was idle or undergoing maintenance the rest of the year. When conditions were calm, she would work productive 16-hour days. For example, on 13 May 1916 she removed of sand weighing approximately 32,000 tons from the shipping channel. In June 1918 Chinook set a ship record, removing . As a result of her work, other dredges, and the construction of jetties at the river mouth, in 1918 the shipping channel at the Columbia Bar was deep and wide. This met the Congressional mandate for the river and Chinook was reassigned. She left Astoria on 22 January 1919.
Chinook arrived in Charleston, South Carolina, via the Panama Canal, on 27 February 1919. She participated in a project to deepen the channel into the harbor. She was then transferred to Hampton Roads, Virginia to dredge the Thimble Shoal channel. She worked on this project intermittently from August 1919 to October 1925 during which time she removed of material. The ship spent much of the remainder of her career assigned to the Portsmouth, Virginia District of the Corps of Engineers and returned to the same channels and rivers multiple times to maintain water depth in the face of constant silting.
Chinook completed a variety of short-term assignments around in the country. At the end of 1920 Chinook was ordered to work in Galveston, Texas. In 1931 she spent a month dredging the channel to Philadelphia. In 1932 and 1933 she was dispatched to New Orleans. Chinook dredged the Egmont Key channel in Florida at various times from 1934 to 1936 In 1936 and 1937 she completed a dredging project in New York Harbor before returning to work in Tampa Bay in 1938. Later that year she spent 30 days deepening Winyah Bay, South Carolina.
In 1925 Newport News Shipbuilding replaced her four boilers with six new ones, and overhauled a number of other systems for $98,500. In 1926 her 20-inch drag arms were removed.
Obsolescence, sale, and scrapping
Chinook was idled in July 1946 and decommissioned in October 1946. She was replaced at Norfolk by USED Comber. Chinook was sold for scrap to the Doane Salvage Company of Bordentown, New Jersey in 1946. The original ship's bell, forged for Mohawk, and which sailed on Grant and Chinook, is held by the US Army Corps of Engineers.
References
1892 ships
Ships built by Harland and Wolff
Ships of the United States Army
Ships built in Belfast
Boxer Rebellion naval ships of the United States
Spanish–American War auxiliary ships of the United States
Dredges | USED Chinook | [
"Engineering"
] | 3,754 | [
"Dredges",
"Mining equipment"
] |
77,908,617 | https://en.wikipedia.org/wiki/Porphyrion%20%28radio%20galaxy%29 | Porphyrion is a Fanaroff–Riley class II radio galaxy located 7.5 billion light years away from Earth, with host galaxy J152932.16+601534.4. It is located in the constellation Draco and it was discovered in Low-Frequency Array (LOFAR) data by an international team led by Martijn Oei. Porphyrion has the longest jets of any radio galaxy identified, with lobed structures spanning across, making it the largest known structure of galactic origin. It superseded Alcyoneus, discovered by the same team in 2022, with lobed structures of .
Discovery
Porphyrion was first reported in a paper in Nature by Martijn Oei (Leiden University/Caltech) and colleagues, which featured on the cover of the 19 September 2024 issue, after obtaining results from the Low Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS), an interferometric radio survey of the Northern Sky. Porphyrion was part of a large number of new giant radio galaxies discovered by this team. The giant black hole jet system was named after Porphyrion, a Giant from Greek mythology, by co-discoverer Aivin Gast from the University of Oxford.
To find the galaxy from which Porphyrion originated, the Giant Metrewave Radio Telescope in India was used along with ancillary data from the Dark Energy Spectroscopic Instrument in Arizona. The observations pinpointed to the galaxy J152932.16+601534.4, which is about 10 times more massive than the Milky Way.
Characteristics
The team reporting the discovery described Porphyrion as a 'black hole jets system', rather than a giant radio galaxy, as they considered the latter a confusing term: the jet structure of a radio galaxy is not formally part of the galaxy proper. Radio galaxies are a special class of objects characterized by the presence of radio lobes generated by relativistic jets powered by the central galaxy's supermassive black hole. Giant radio galaxies are different from ordinary radio galaxies in that they can extend to much larger scales, reaching upwards to several megaparsecs across, far larger than the diameters of their host galaxies.
The W. M. Keck Observatory on Hawaii was used to show that Porphyrion is 7.5 billion light-years from Earth, and dates to a time when the universe was 6.3 billion years old. The observations also revealed that Porphyrion emerged from a radiative-mode active black hole, as opposed to one in a jet-mode state. Porphyrion's two jets combined have a jet power of 1039 watts, equivalent to the energy output of trillions of suns.
Oei and his colleagues believe that "every place in the universe may have been affected by black hole activity at some point in cosmic time". They suggest that giant jet systems like Porphyrion may have had a larger influence on the formation of galaxies in the young universe than previously believed, and suggest that these giant jets could have spread magnetism through the cosmos.
See also
List of largest galaxies
List of galaxies with notable features
References
Radio galaxies
Active galaxies
Astronomical radio sources
Draco (constellation) | Porphyrion (radio galaxy) | [
"Astronomy"
] | 655 | [
"Astronomical radio sources",
"Astronomical events",
"Constellations",
"Draco (constellation)",
"Astronomical objects"
] |
77,908,859 | https://en.wikipedia.org/wiki/LPC-233 | LPC-233 is an experimental antibiotic drug. It acts as a potent and selective inhibitor of the bacterial enzyme UDP-3-O-acyl-N-acetylglucosamine deacetylase (LpxC), which is important for the production of Lipid A, a key component of the cell membrane of Gram-negative bacteria. Various inhibitors of LpxC have been developed but none have yet progressed into clinical trials in humans, mostly because of off-target cardiovascular toxicity. LPC-233 is one of the most advanced drugs of this type in preclinical testing, showing activity against several pathogens of concern such as multidrug-resistant Pseudomonas aeruginosa and carbapenem resistant Enterobacter strains, and with no cardiovascular toxicity evident in testing on mice and dogs.
See also
TP0586532
References
Antibiotics
Diynes
Cyclopropyl compounds
Hydroxamic acids
Benzamides
Difluoromethyl compounds | LPC-233 | [
"Chemistry",
"Biology"
] | 208 | [
"Biotechnology products",
"Functional groups",
"Organic compounds",
"Antibiotics",
"Biocides",
"Hydroxamic acids"
] |
77,911,738 | https://en.wikipedia.org/wiki/Markarian%20463 | Markarian 463 (Mrk 463) known as UGC 8850, is a galaxy merger located in the constellation Boötes. It is located 706 million light years from Earth. It is classified a double nucleus Seyfert galaxy.
Characteristics
Markarian 463 is a late stage galaxy merger, a product of two gas-rich spiral galaxies colliding with one another. According to optical and near-infrared observations, the galaxy is shown to have a complex morphology with star forming clumps and curved tidal tails. It has a luminosity of LIR (8–1000μm) = 1011.8 LΘ making it a luminous infrared galaxy. It contains a compact radio flux in either linear or elongated structure. Using spectra captured by the Infrared Spectrograph installed on Spitzer Space Telescope, emission lines are detected in Markarian 463 hinting a warm supply of molecular gas.
A broadband X-ray spectral analysis revealed obscured two nuclei designated as Markarian 463W and Markarian 463E, with an estimated projected separation of ~ 3.8 kiloparsec. This finding makes the galaxy a dual active galactic nucleus and is the third closest physical pair known after NGC 6240 and NGC 3758. The two nuclei has a luminosity of L2–10keV = and . Both are active and are expected to drawn close to each other over timescales of 108 years.
The western nucleus has a moderate radio luminosity equivalent of an extremely luminous starburst galaxy or a Seyfert galaxy through imaging detections at 6 and 20 centimeters. The eastern nucleus however, is much brighter compared to the western nucleus, and is classfied a type II Seyfert galaxy. It is found offset from its peak flux and shows polarized conical wind. With a half-opening angle of ~ 15 degrees, its wind displays three mass ejection periods. Using infrared spectroscopy, the eastern nucleus hosts a hidden Seyfert 1 nucleus located southwards but not co-spatial.
According to Chandra X-ray data, the supermassive black hole in the nucleus of Markarian 463E has a much higher accretion rate of ~ 5x. It is also associated with emission and continuum lines. It is also shown it is older compared the nucleus of Markarian 463W, given the northern outflowing cloud and southern emission region appears generally aligned with the biconical gradient. An ALMA 12CO (2–1) observation also finds the two nuclei have molecular gas reservoirs estimated of ~ 109 MΘ and ~ 5 × 108 MΘ respectively. Given enough molecular gas provided, it is enough to feed both black holes in the galaxy.
Markarian 463 has an optical jet originating from the Seyfert nucleus according to Hubble Space Telescope imaging. The jet is found to reach the end at the radio source found 1.2 arcsecs away, and is measured 0.84 arcsecs with a position angle of 182 degrees.
Part of the galaxy shows emission due to oxygen, first identified with Hubble. This was interpreted as a possible extended emission-line region (EELR).
Gallery
References
Markarian galaxies
Boötes
Luminous infrared galaxies
Interacting galaxies
049538
IRAS catalogue objects
Seyfert galaxies
08850
MCG objects | Markarian 463 | [
"Astronomy"
] | 678 | [
"Boötes",
"Constellations"
] |
77,911,947 | https://en.wikipedia.org/wiki/HotDog%20domain | In molecular biology, the HotDog domain is a protein structural motif found in a diverse superfamily of enzymes, primarily thioesterases and dehydratases. The name "HotDog" refers to its characteristic structure, where a central α-helix (the "sausage") is wrapped by a curved β-sheet (the "bun").
Structure
The HotDog domain consists of a central α-helix (typically 5 turns long) and an antiparallel β-sheet (usually 5-7 strands) that wraps around the α-helix. The basic structural unit of HotDog domain proteins is typically a homodimer, formed by the association of two monomers or two tandem copies of the domain. However, more complex quaternary structures, including tetramers and hexamers, have been observed.
Function
Proteins containing the HotDog domain are primarily involved in thioester hydrolysis, various ehydration reactions and acyl transfer reactions. Hotdog fold protein play roles in various metabolic pathways, such as fatty acid biosynthesis and degradation, polyketide biosynthesis and phenylacetic acid degradation.
Enzyme families
The HotDog domain superfamily includes several enzyme families, such as:
4-hydroxybenzoyl-CoA thioesterases
FabA-like dehydratases
YbgC-like acyl-CoA thioesterases
TesB-like thioesterases
MaoC dehydratase-like enzymes
Catalytic mechanism
The catalytic mechanism of HotDog domain enzymes varies depending on the specific enzyme and reaction. However, many of these enzymes share common features in their active sites including a conserved catalytic triad or dyad, often including aspartate, glutamate, or serine residues. A nucleophilic attack mechanism, typically involving an activated water molecule and substrate binding sites that accommodate the CoA moiety and the acyl group.
Evolution and distribution
HotDog domain proteins are found in all three domains of life: Bacteria, Archaea, and Eukaryota. Their widespread distribution suggests an ancient evolutionary origin. Despite low overall sequence similarity, the structural conservation of the HotDog fold implies a common ancestor for these diverse enzymes.
See also
Protein fold
Thioesterase
Dehydratase
Fatty acid synthesis
References
External links
InterPro: HotDog domain superfamily (IPR029069)
Protein domains
Protein folds
Protein superfamilies
Enzymes | HotDog domain | [
"Biology"
] | 499 | [
"Protein superfamilies",
"Protein domains",
"Protein classification"
] |
77,911,978 | https://en.wikipedia.org/wiki/HD%2011343 | HD 11343 (HIP 8541) is a wide binary system between HD 11343 A, a K-type borderline giant star, and HD 11343 B, a red dwarf companion, located in the southern constellation of Eridanus about distant. Two gas giant exoplanets are known to orbit the primary star.
Stellar characteristics
The HD 11343 system has an apparent magnitude of 7.88, making it too faint to be visible by the naked eye from Earth under most circumstances, but can be observed using binoculars as an orangish dot near Achernar.
The primary component, HD 11343 A, is a red-giant branch star slightly more massive than the Sun (albeit one estimate places its mass at a significantly higher 2.0 ), but approximately eight times as large in radius and 25 times as luminous. It has an effective temperature of , corresponding to its spectral type of K2, and is slightly metal-poor, with an iron content 71% that of the Sun.
During a 2021 survey searching for binaries within data from Gaia EDR3, the star was found to be orbited by a 13th-magnitude M-dwarf, designated HD 11343 B. It is about 70% as large as the Sun both in mass and radius, is slightly cooler than the primary red giant at , and is situated at a separation of roughly from its brighter companion.
Planetary system
In 2016, a super-Jupiter planet orbiting HD 11343 A was discovered from radial-velocity observations, alongside three other substellar companions to giant stars, namely HIP 74890 b, HIP 84056 b, and HIP 95124 b. This planet, HD 11343 b, is estimated to be slightly larger than Jupiter and has a mass of 5.7 , close to the initially estimated minimum of 5.5 . It revolves around its host star at a semi-major axis of , around where the asteroid belt would lie in the Solar System, every in a mildly eccentric orbit.
Another planet, HD 11343 c, was discovered in 2022 closer to HD 11343 A, also using the radial-velocity method. The planet is reportedly a Jupiter analog, larger than the previous planet but likely considerably less massive, with a minimum mass of 0.804 . It orbits its star at a distance of every . Due to the faintness of the astrometric signals it produces, its orbital inclination cannot be well-constrained. The discovery paper for HD 11343 c notably presents a higher mass ( ), semi-major axis (3.729 AU), orbital period (5.07 years), and eccentricity (0.360) for HD 11343 b.
Footnotes
References
External links
Extrasolar Planets Encyclopaedia links: HD 11343 b, c
Eridanus (constellation)
011343
008541
CD-55 00412
K-type giants
K-type subgiants
Planetary systems with two confirmed planets
J01500631-5427539
Planetary systems
Stars | HD 11343 | [
"Astronomy"
] | 613 | [
"Eridanus (constellation)",
"Constellations"
] |
77,912,374 | https://en.wikipedia.org/wiki/Load%20modulation | Load Modulation is a method of conveying a signal from one device to another by means of modulating the load that the transmitting device imposes on a radio signal provided by the receiving device.
This is used, for example, to allow ISO/IEC 14443 and ISO/IEC 15693 NFC cards to reply to the reading device without the need for the NFC card to contain a power source. Instead, it is powered by the radio signal provided by the reader and it conveys its data back to the reader by modulating the load that the NFC card imposes upon the reader's radio signal.
References
Signal transmission | Load modulation | [
"Physics",
"Technology",
"Engineering"
] | 127 | [
"Physical phenomena",
"Telecommunications engineering",
"Waves",
"Information technology",
"Signal transmission"
] |
77,913,732 | https://en.wikipedia.org/wiki/Thomas%20Carnelley | Thomas Carnelley (22 October 1854 – 27 August 1890) was a British chemist who contributed to physical chemistry and was involved in introducing German-inspired chemistry research into Britain as professor of chemistry at the University of Dundee and later at Aberdeen. He studied the relationships between the melting and boiling points of the salts of elements and their positions in the periodic table. He also examined relationships between molecular structures and physical properties and came up with a rule that is sometimes called "Carnelley's Rule".
Life and work
Carnelley was born in Manchester, the son of William. He studied at King's College School, London and joined Owens College, Manchester in 1868. He showed scholastic brilliance and received a Bachelor of Science in 1871 with a third position in Third Class Honors in Chemistry. In 1872 he obtained second place in First Class Honors in Chemistry qualifying for a university scholarship. He studied the vanadates of thallium that led to a Dalton Chemical Scholarship and he worked as a private assistant to Henry Enfield Roscoe in 1872-74 giving lectures in the evening at Owens College. He then went to the University of Bonn and studied under August Kekulé (1829–1896), Theodor Zincke (1843–1928), and Otto Wallach (1847–1931). He studied the reactions of carbon disulfide and alcohol with hot copper catalysts and the synthesis of tolylphenyl. He received a doctorate in 1876 and in 1879 he received a DSc from the University of London. He was appointed to Firth College, Sheffield in 1879 where he established a chemistry laboratory and in 1881 he moved to the University College of Dundee where he had more resources. He taught with great zeal and was popular among students. He also conducted research on the heating and ventilation of schools, the quality of air in buildings and so on leading to his being elected to the school board. He also established a museum and a dye-house with material contributed by Carnelley's father to the college. In 1888 he accepted the chair of chemistry at the University of Aberdeen following the death of James Smith Brazier. Two years after moving to Aberdeen, he suffered from a sudden illness and an internal abscess. He died at home in Cults, Aberdeen at the age of 36.
Carnelley helped introduce the German style of chemical research and industrial applications into Britain. He was elected to the Chemical Society of London in 1874. He published more than 50 papers and several textbooks. He studied the synthesis of several hydrocarbons including tolylphenyl and ditolyl and examined the physics of ice. In his 1879 work, he examined the melting points of metallic salts and related them to their positions in the periodic table. Mendeleeff took notice of the work and wrote to Henry Roscoe that Carnelley's work deserved wide knowledge. He stated that: “The labors of Carnelley connected with the periodic law of the elements have been so remarkable that the history of the subject would be incomplete if his name were omitted.” Carnelley and Thomas Burton developed a new pyrometer to measure high temperatures. It was made of a coil of copper tubing which carries water through it. Measurement was made of the water temperature at the inlet and at the outlet and he calibrated these with known temperatures. In 1881 he claimed that it was possible to maintain ice at solid phase at temperatures above the normal melting point under pressure. In 1880 the sublimation of ice was demonstrated at low temperatures.
Carnelley's Rule states that of two or more isomers, those whose atoms are the more symmetrically and the more compactly arranged melt higher than those in which the atomic arrangement is asymmetrical or in the form of long chains.
His interest in public hygiene led to his being appointed to a committee to examine the air and smells in the House of Commons in 1886. Carnelley and J.S. Haldane were asked to examine the quality of the air. The studied the carbon dioxide levels in the sewers and in the rooms. He also adapted a bacteriological analysis using Hesse's method.
References
External links
Melting and boiling point tables (1885–7)
Physico-chemical constants. Melting and boiling point tables. Volume 1 Volume 2
Carnelley building housing the chemistry laboratory at Dundee
1854 births
1890 deaths
English chemists
Physical chemists | Thomas Carnelley | [
"Chemistry"
] | 894 | [
"Physical chemists"
] |
77,913,770 | https://en.wikipedia.org/wiki/Acer%20amamiense | Acer amamiense (also known as Amami maple) is a rare species of maple in the Sapindaceae family. It is native to Amami-Oshihma, in southern Japan.
Description
Acer amamiense is a round-topped, deciduous tree, growing to about in height in the wild. New leaves are a deep purplish colour. Mature leaves are five-lobed and green, turning a bright red-purple in autumn. It resembles Acer diabolicum, but differs in having glabrous petioles and short-haired, rather than bristly fruit. Yellow flowers are produced before the leaves open in spring, followed by brown winged fruits on female plants.
Distribution and habitat
Discovered in 1999, Acer amamiense is considered a critically endangered species, with a very limited native range, and only a dozen specimens existing in the wild. It favours acidic soil and a temperate mountain habitat.
References
Flora of Japan
Endangered species
amamiense | Acer amamiense | [
"Biology"
] | 202 | [
"Biota by conservation status",
"Endangered species"
] |
77,917,124 | https://en.wikipedia.org/wiki/Cellular%20extensions | Cellular extensions also known as cytoplasmic protrusions and cytoplasmic processes are those structures that project from different cells, in the body, or in other organisms. Many of the extensions are cytoplasmic protrusions such as the axon and dendrite of a neuron, known also as cytoplasmic processes.
Different glial cells project cytoplasmic processes. In the brain, the processes of astrocytes form terminal endfeet, foot processes that help to form protective barriers in the brain. In the kidneys specialised cells called podocytes extend processes that terminate in podocyte foot processes that cover capillaries in the nephron. End-processes may also be known as vascular footplates, and in general may exhibit a pyramidal or finger-like morphology. Mural cells such as pericytes extend processes to wrap around capillaries.
Foot-like processes are also present in Müller glia (modified astrocytes of the retina), pancreatic stellate cells, dendritic cells, oligodendrocytes, and others. Microglia, which are notably smaller than macroglia, can also extend their end-processes to contact areas of capillaries that are devoid of astrocyte endfeet, and thereby contribute to the formation of the glia limitans.
Other cellular extensions that protrude from the cell membrane are known as membrane protrusions or cell protrusions, also cell appendages, such as flagella, and microvilli. Microtentacles are cell protrusions attached to free-floating cells, associated with the spread of some cancer cells.
In prokaryotes such protrusions are known as surface or cell-surface appendages and include flagella, pili, fimbriae, and nanowires. Some archaea possess very complex appendages known as hami.
Types
Neuronal processes
The cytoplasmic processes of a neuron are the axons and dendrites differentiated from the precursor neuronal processes known as neurites.
A dendritic spine is a membrane protrusion from a dendrite.
Glial processes
The processes of glial cells include contractile processes, and processes in astrocytes that terminate in foot processes known as endfeet.
Epithelial cell processes
The podocyte is a highly specialised epithelial cell in Bowman's capsule in the kidney. Primary processes of the podocytes form terminal foot processes. The podocyte foot processes wrap around the glomerular capillaries in the kidney to function in the filtration barrier.
Foot processes vs. lamellipodia and filopodia
The difference between foot processes, and lamellipodia, which are broad sheet-like protrusions, and filopodia, which are long slender pointed extensions, is that lamellipodia and filopodia are especially significant for cell movement and migration, and they are "macro" membrane protrusions. In contrast, foot processes interact with basement membranes, and are present at the "micro" scale.
However, cellular extensions, in general, can be found on a larger "macro" scale, occupying relatively large areas of the cell membrane. For example, microglia can use their primary processes to constantly monitor and evaluate alterations in the brain environment, and they can further deploy thin filopodia from these primary processes to expand their surveillance area.
Architectural similarities
The arborization and branching of end-processes are one of the features responsible for the structural and functional similarities among various cell types. Podocytes and pericytes share many physiological properties due to their large surface areas and intricate network of primary and secondary processes that wrap around their associated capillaries.
In addition, foot processes of podocytes and dendritic extensions of neurons exhibit comparable morphological features, and molecular machinery as they both share similar proteins found at both synapses and foot processes, such as synaptopodin and dendrin. This analogy between them is further supported by their shared vulnerability to pathological conditions such as Alzheimer's disease and minimal change nephropathy, both of which are characterized by reduction and damage of dendritic spines and foot processes respectively.
Membrane protrusions
Membrane protrusions or cell appendages, extend from the cell membrane, and include microvilli, cilia, and flagella. Microvilli increase the surface area of a tissue, such as from their abundance on tissue protrusions such as intestinal villi.
There is increasing evidence that membrane protrusions may act as platforms for the budding of extracellular vesicles.
Structure
The cytoskeleton
One key distinction between cellular processes and lamellipodia lies in the composition of their cytoskeletal elements. While cellular processes can be supported by any of the three major components of the cytoskeleton—microfilaments (actin filaments), intermediate filaments (IFs), or microtubules—, lamellipodia are primarily driven by the polymerization of actin microfilaments, not microtubules.
Microtubules are generally unable to generate the force required by lamellipodia for large-scale cell movement, as this requires a significant number of microtubules to reach the cell's leading edge in order to produce sufficient force to promote the development of significant protrusions and motility. As a result, lamellipodia are predominantly actin-based rather than microtubule-based.
On the other hand, cellular processes can be:
Microtubule-based: Similar to neurons and dendritic cells, microtubules form the main structural core of primary processes of podocytes. In addition, oligodendrocytes possess two distinct types of microtubules:
Radial microtubules: They are located in the proximal regions of the ramified processes of oligodendrocytes, that extend outward from the cell body.
Lamellar microtubules: They are the microtubules that eventually wrap around the axon, forming the myelin sheath.
Actin-based: These include terminal foot processes of podocytes and dendritic spines (small protrusions arising from dendrites).
IF-based: The predominant cytoskeletal element within astrocyte processes at birth is microtubules. However, as these cells mature, a significant shift occurs, with microtubules being almost completely replaced by intermediate filaments (IFs), composed predominantly of glial fibrillary acidic protein (GFAP), found in the end-feet of Müller cells and astrocytes.
Numerous imaging methods, such as immunohistochemistry and fluorescence microscopy, have enabled the precise targeting of, and are currently used to identify, visualize and localize specific marker proteins in foot processes, such as GFAP and synaptopodin. Such techniques can be used to stain and study cells or identify relevant pathological changes.
The mitochondria
In cells with unique architecture, energy requirements can vary significantly among different cellular compartments. As a result, mitochondria, within such cells, demonstrate a non-uniform distribution, and can be strategically localized in regions with the greatest energy needs.
In order to support the substantial metabolic demands of neurovascular coupling, astrocytic endfeet are loaded and packed with elongated and branched mitochondria. This represents a marked departure from the typical pattern, wherein mitochondria generally tend to become smaller as their distance from the cell body increases, particularly within the fine branches and branchlets.
However, while fine astrocytic perisynaptic processes can only house the smallest mitochondria, perivascular endfeet present a notable exception, and they can accommodate significantly more complex and ramified mitochondria. In cases of traumatic brain injury and subsequent blood-brain barrier disruption, there is even further augmentation in mitochondrial number and density within astrocytic endfeet in order to facilitate vascular remodeling as an adaptive response.
On the contrary, foot processes of podocytes are devoid of mitochondria, and mitochondria are confined to the cytosol surrounding the nucleus. The absence of mitochondria in foot processes can be attributed to the apparent size disparity, since mitochondria are generally larger than foot processes (The diameter of foot processes of normal podocytes can be under 250 nm).
As a result, foot processes rely on glycolysis for their energy supply, which may be beneficial as glycolysis offers the advantage of being unrestricted by a maximum capacity. Mitochondria, on the other hand, have a maximal limit, that renders them incapable of generating additional energy upon increased demand.
Energy requirements of foot processes of podocytes
Podocytes require a significant amount of energy to preserve the structural integrity of their foot processes, given the substantial mechanical stress they endure during the glomerular filtration process.
Dynamic changes in glomerular capillary pressure exert both tensile and stretching forces on podocyte foot processes, and can lead to mechanical strain on their cytoskeleton. Concurrently, fluid flow shear stress is generated by the movement of glomerular ultrafiltrate, exerting a tangential force on the surface of these foot processes.
In order to preserve their intricate foot process architecture, podocytes require a substantial ATP expenditure to maintain their structure and cytoskeletal organization, counteract the elevated glomerular capillary pressure and stabilize the capillary wall.
It has also been suggested that podocytes may possess a reasonable degree of mobility along the glomerular basement membrane, a process that may also contribute to the high energy demand. Since filtered proteins may become entrapped and accumulate under podocyte cell body and major processes, a hypothesized strategy to facilitate the removal of these stagnant proteins involves a cyclical movement of podocytes, allowing trapped proteins to be dispersed from the subpodocyte space into the filtrate.
Function
End-processes are integral to the structure of diverse membranes and sheaths, and perivascular cells play a crucial role in the formation and maintenance of organ-blood barriers:
Regulation of blood flow
Cellular extensions of certain mural cells possess the capability to regulate the diameter of their associated blood vessels. Through the processes of vasoconstriction and vasodilation, these cells can actively control the rate of blood flow by means of:
Contraction of cellular processes that encircle capillaries as in pericytes, which possess contractile proteins such as α-actin, tropomyosin, and myosin enabling them to contract and relax.
Synthesis of vasomodulatory eicosanoids as in astrocytic endfeet. These endfeet are able to produce prostaglandin E2 (PGE2), a potent vasodilator, and 20-hydroxyeicosatetraenoic acid (20-HETE), a vasoconstrictor, both of which exert their effects on vascular smooth muscle cells in arterioles and pericytes in capillaries, leading to the vasodilation and vasoconstriction respectively.
Barrier and permeability regulation
Podocytes, through their intricate network of foot processes, strictly control the passage of plasma proteins into the urinary ultrafiltrate. Podocytes establish a selective barrier between their foot processes, allowing only molecules of appropriate size and charge to traverse. The negatively charged glycocalyx coating the foot processes facing the urinary space further enhances this barrier, creating an electrostatic repulsion that impedes the filtration of albumin.
Uptake and flux of ions, water and nutrients
Astrocytic endfeet are rich in:
GLUT1 transporters, responsible for the transport of glucose across the BBB into astrocytes (This is in contrast to GLUT3 transporters that are localized on the neural end-processes).
L-type amino acid transporter (LAT), responsible for transporting large neutral amino acids across the BBB.
Aquaporin-4 water channels, responsible for water and potassium homeostasis.
Cellular interaction
Osteocytes
The vascularization of bone is a metabolically demanding process, requiring substantial energy to support the proliferation and migration of endothelial cells. As a result, capillaries which arise from the bone marrow, and then pass through the cortical (outer) layer of bone, known as transcortical vessels (TCVs), require a robust supply of mitochondria to facilitate vascular development.
Osteocytes, the most common cell type within mature cortical bone, actively participate in the growth and maintenance of TCVs through the transfer of mitochondria to endothelial cells. Scanning electron microscopy images have revealed that osteocytes possess numerous dendritic processes with expanded, endfoot-like structures. These endfeet directly abut and communicate with TCVs, establishing a close physical association that enables the transfer of mitochondria, and thereby provide the endothelial cells with the energy necessary for vascularization.
Pericytes
While chemical signalling pathways have long been recognized as key mediators of intercellular communication, recent studies have highlighted the significance of direct physical interactions in facilitating coordinated cellular responses. For example, pericyte secondary processes establish contact with endothelial cells, resulting in the formation of peg-socket invaginations, where pericyte processes extend inward, forming indentations within the endothelial cell membrane.
During the process of angiogenesis, newly formed microvessels typically consist of rapidly dividing endothelial cells and an immature basement membrane. Subsequent maturation of these microvessels involves the recruitment of pericytes. The presence of pericytes surrounding blood vessels is often associated with the inhibition of endothelial cell proliferation and the stabilization of newly formed microvessels.
In diabetic retinopathy (DR), accumulation of toxic substances such as advanced glycation end-products (AGEs) leads to pericyte loss, weakening of capillary walls, and microaneurysms, all are hallmarks of DR. Abnormal changes in pericyte mechanical stiffness can impair their ability to maintain the arrest of capillary endothelial cell growth, which may be involved in angiogenesis, neovascularization, and proliferative DR.
Cytotoxic T cells
Traditionally, CD8+ T-cells, responsible for combating intracellular pathogens, are required to undergo a multi-step migration process to reach infected organs. This process involves rolling along the endothelial surface, firm adhesion to the endothelium, and subsequent extravasation into the surrounding tissue. Nevertheless, in the liver, the fenestrated endothelium of hepatic sinusoids allows for direct contact between CD8+ T-cells and the hepatocytes.
In case of viral or bacterial infection of hepatocytes, platelets have been observed to form clusters within the sinusoids of the liver and adhere to the surface of infected Kupffer cells. This aggregation is believed to serve as a mechanism for trapping pathogens and promoting their elimination by the immune system.
CD8+ T-cells, encountering platelet aggregates within liver sinusoids, are arrested and actively migrate along these sinusoids. They stretch out foot-like processes through the sinusoidal pores into the space of Disse, and then scan hepatocytes for detection of infected cells. Upon recognition of antigens, these T cells initiate a cytotoxic response characterized by producing cytokines and killing infected cells without the need for extravasation into the liver parenchyma.
Microglia
Microglia, while primarily known for their immunological functions, exhibit remarkable plasticity, enabling them to perform a diverse range of roles within the central nervous system. Traditionally, microglia have been characterized as existing in two distinct morphological states that correlate with changes in their functional properties:
Clinical significance
Foot process effacement
Foot process effacement (FPE) is a pathological condition, where podocyte foot processes withdraw from their usual interdigitating position, retract into the primary processes of podocytes, and eventually fuse with the cell bodies, resulting in the formation of broad sheet-like extensions over the glomerular basement membrane (GBM).
The podocyte cell bodies no longer maintain their typical position "floating" within the filtrate above the GBM. Instead, they become broadly adherent to it, resulting in the near-complete obliteration of the subpodocyte space, the region beneath the podocyte cell body and major processes.
FPE is a typical finding in proteinuric glomerular diseases, including minimal change disease (MCD), membranous nephropathy, diabetic kidney disease, and IgA nephropathy. FPE is hypothesized to be an adaptive mechanism in response to glomerular stress, rather than a mere consequence of cell injury and disease.
For example, in inflammatory diseases such as anti-GBM glomerulonephritis, inflammatory mediators and the activation of the complement cascade can damage the attachment of the actin cytoskeleton in foot processes to the GBM, thereby increasing the risk of podocyte detachment from the GBM.
As a result, podocytes undergo cytoskeletal reorganization, resulting in the formation of a robust, basal cytoskeletal network that is tightly adhered to the GBM in order to minimize the risk of podocyte detachment. Even in cases of extensive FPE, recovery from effacement is possible if the disease resolves or with therapeutic intervention, and podocytes can restore their foot processes to their normal interdigitating state.
Staphylococcus epidermidis infections
Staphylococcus epidermidis, a common bacterium found as a normal commensal on human skin, is a significant cause of hospital-acquired infections that are associated with the use of implanted medical devices like heart valves and catheters.
This bacterium can reach the bloodstream as a contaminant from the skin, adhering to an implant using various mechanisms. In addition to producing a slimy substance, S. epidermidis can anchor itself to the surface of the implant using foot-like processes. These projections (appendages) extend from the bacterial cell wall and attach to the implant in linear arrangements, either singly or in multiples.
Aquaporin-4
Neuromyelitis optica spectrum disorder
Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune inflammatory disease characterized by the presence of serum antibodies directed against the water channel protein aquaporin-4 (AQP-4). These antibodies initiate a complement-dependent inflammatory cascade, culminating in tissue damage and destruction.
Given that AQP4 is primarily expressed on perivascular astrocytic endfeet in the spinal cord and by Müller cells in the retina, NMOSD preferentially affects the spinal cord, and the anterior visual system.
Patients with NMOSD typically exhibit worse visual acuity compared to those with multiple sclerosis (MS), because NMOSD is primarily an inflammatory process targeting astrocytes, with demyelination as a secondary consequence. In contrast, MS primarily involves inflammatory demyelination.
Since NMOSD targets Müller cells, which provide trophic support to the retina, and have a heightened expression of AQP4 in their endfeet facing blood vessels, it is evident that NMOSD can have a more severe impact on visual acuity.
Alzheimer's disease
AQP-4 exhibits a polarized distribution in astrocytes, with a 10-times higher concentration in astrocytic endfeet, which are in contact with blood vessels, compared to non-endfoot regions.
In contrast to the lateral membranes of numerous epithelial cell types, astrocyte lateral membranes are devoid of tight junctions, that prevent diffusion of membrane molecules. In order to maintain their polarization and orientation towards blood vessels, AQP-4 channels must be securely anchored by specialized proteins.
Recent studies have revealed a correlation between multiple neurological disorders, and the loss of AQP4 polarity (i.e. when AQP4 are widely distributed throughout the astrocyte, instead of its typical localization at the endfeet).
AQP-4 facilitates the flow of cerebrospinal fluid through the brain parenchyma from para-arterial to para-venous spaces, and thus AQP4 channels facilitate the clearance of waste products from the brain, thereby preventing their accumulation. In Alzheimer's disease (AD), a disruption in the polarity of AQP4 can cause a buildup of waste products, such as amyloid beta and tau proteins, a defining characteristic of AD.
This also explains why patients with NMSOD are at higher risk of developing AD, since damage of AQP4 in NMSOD may impair clearance of amyloid-beta.
Epiretinal membrane
An epiretinal membrane (ERM) is an eye disease, where a greyish semi-translucent membrane progressively grows over the macula, leading to decreased visual acuity, metamorphopsia, and other complaints. ERM commonly occurs due to posterior vitreous detachment, which can cause a tear in the internal limiting membrane (ILM), allowing microglial cells to migrate through the disrupted retinal architecture and interact with other cells at the vitreo-retinal interface, ultimately contributing to the formation of ERM.
The standard surgical treatment for symptomatic ERMs is pars plana vitrectomy with membrane peel. However, despite the apparent complete removal of the ERM, there remains a risk of recurrence, which can be attributed to the presence of residual microscopic ERM remnants and the potential role of Müller cell footplates in the internal limiting membrane (ILM) in facilitating further cell proliferation and membrane formation. Minimising recurrence can therefore be achieved through peeling the underlying ILM together with the ERM.
However, ILM peeling may result in the unintended damage of Müller cells, thereby increasing the risk of complications such as development of dissociated optic nerve fiber layer (DONFL), probably due to trauma to Müller cell footplate, and concomitant alterations in the nerve fiber layer and ganglion cell layer. As a result, intraoperative optical coherence tomography (iOCT)-guided ERM removal is an alternative approach that may minimize the risk of recurrence without the need for routine ILM peeling.
Notes
References
Actin-based structures
Cell anatomy
Cell biology | Cellular extensions | [
"Biology"
] | 4,768 | [
"Cell biology"
] |
77,917,922 | https://en.wikipedia.org/wiki/List%20of%20most%20massive%20neutron%20stars | Below is a list of high-mass neutron stars.
See also
Blitzar
List of least massive black holes
List of most massive black holes
List of neutron stars
Tolman–Oppenheimer–Volkoff limit
Quark star
References
Neutron stars
Lists of superlatives in astronomy
Heaviest or most massive things | List of most massive neutron stars | [
"Physics",
"Astronomy"
] | 61 | [
"Astronomy-related lists",
"Lists of superlatives in astronomy",
"Mass",
"Heaviest or most massive things",
"Matter"
] |
77,918,096 | https://en.wikipedia.org/wiki/TP0586532 | TP0586532 is an experimental antibiotic drug, which acts as a potent and selective inhibitor of the bacterial enzyme UDP-3-O-acyl-N-acetylglucosamine deacetylase (LpxC). This enzyme is important for the production of Lipid A, a key component of the cell membrane of Gram-negative bacteria. Previous inhibitors of LpxC have failed to progress into clinical trials in humans, mostly because of off-target cardiovascular toxicity, so TP0586532 was based on a different structural class which is hoped to reduce this risk. In animal studies it shows activity against carbapenem-resistant Klebsiella pneumoniae but has not yet progressed into human trials.
See also
LPC-233
References
Antibiotics
Alcohols
Alkynes
Benzene derivatives
Carboxylic acids
Cyclopropanes
Imidazoles
Isoxazoles
Pyrrolidines | TP0586532 | [
"Chemistry",
"Biology"
] | 197 | [
"Alkynes",
"Biotechnology products",
"Carboxylic acids",
"Functional groups",
"Organic compounds",
"Antibiotics",
"Biocides"
] |
77,919,001 | https://en.wikipedia.org/wiki/HRAC%20classification | The Herbicide Resistance Action Committee (HRAC) classifies herbicides by their mode of action (MoA) to provide a uniform way for farmers and growers to identify the agents they use and better manage pesticide resistance around the world. It is run by CropLife International in conjunction with the Weed Science Society of America (WSSA).
Resistance overview
A weed that develops resistance to one herbicide typically has resistance to other herbicides with the same mode of action (MoA), so herbicides with different MoAs, or different resistance groups, are needed. Preventative weed resistance management rotates herbicide types to prevent selective breeding of resistance to the same mode of action. By rotating MoAs, successive generations gain no advantage from any resistant mutations of the last generation. Cross-resistant and multiply resistant weeds resist multiple MoAs, and are particularly difficult to control.
There is limited evidence of resistance undoing other resistances. For example, prosulfocarb and trifluralin: their inverse mechanisms of resistance contradict, and so by evolving to one the weed loses resistance to the other, at least by metabolic resistance. Prosulfocarb requires a weed to metabolise it very slowly to survive; trifluralin on the other hand must be metabolised quickly before it can deal damage to the weed.
Naming types
The HRAC give a letter based class to each active constituent herbicide. The Australian HRAC code is separately assigned, though is often the same as the global code. In 2021, alternative numeric classes were added, to make codes globally more consistent. This set of classification changes also added or moved a few herbicides that had been misclassified, and reduced regional concerns that using the English alphabet could be an impediment for international growers.
Herbicides that act through multiple modes have multiple classifications, corresponding to each MoA. For example, Quinmerac is classified as Group 4/29 (O/L) because it is both an Auxin mimic (Group 4 or O) and inhibits cellulose synthesis (Group 29 or L).
Groups
See also
Insecticide Resistance Action Committee
References
Herbicides | HRAC classification | [
"Biology"
] | 443 | [
"Herbicides",
"Biocides"
] |
73,548,277 | https://en.wikipedia.org/wiki/Henize%2070 | Henize 70 (N70) is a faint emission nebula and superbubble located in the Large Magellanic Cloud in the constellation of Dorado.
Observation history
Henize 70 was first observed in 1950 in a survey of bright planetary nebulae. Based on appearance it was proposed that it might be a supernova remnant. In 1956, it was added to a catalogue of Hα emission stars and nebulae by Karl Gordon Henize, where it was described as an emission nebula rather than a planetary nebula.
Origins
A paper published in 1978 proposed that the formations of Henize 70 and other emission nebulae could be due to stellar winds. Later in 1981, a scientific article mentioned a higher likeliness of a supernova explosion forming the nebula instead of stellar winds. A 2014 study measured that Henize 70 featured high SII and Hα ratios, indicating that it is not a supernova remnant.
Henize 70 has spectral line ratios relatively similar to that of supernova remnants due to having similar SII/Hα line ratios although most supernova remnants have higher NII/Hα line ratios.
Notes
References
Emission nebulae
Superbubbles
Dorado
Large Magellanic Cloud | Henize 70 | [
"Astronomy"
] | 238 | [
"Dorado",
"Constellations"
] |
73,548,756 | https://en.wikipedia.org/wiki/Animals%20in%20Meitei%20culture | Animals () have significant roles in different elements of Meitei culture, including but not limited to Meitei cuisine, Meitei dances, Meitei festivals, Meitei folklore, Meitei folktales, Meitei literature, Meitei mythology, Meitei religion, etc.
Deer in Meitei culture
In one of the epic cycles of incarnations in Moirang, Kadeng Thangjahanba hunted and brought a lovely Sangai deer alive from a hunting ground called "Torbung Lamjao" as a gift of love for his girlfriend, Lady Tonu Laijinglembi.
However, when he heard the news that his sweetheart lady married King Laijing Ningthou Punsiba of ancient Moirang, during his absence, he got extremely disappointed and sad. And so, with the painful and sad feelings, he realised and sensed the feelings of the deer for getting separated from its mate (partner). So, he released the deer in the wild of the Keibul Lamjao (modern day Keibul Lamjao National Park regions). Since then, the Sangai species started living in the Keibul Lamjao region as their natural habitat.
Dogs in Meitei culture
Dogs are mentioned as friends or companions of human beings, in many ancient tales and texts. In many cases, when dogs died, they were given respect by performing elaborate death ceremonies, equal to that of human beings.
When goddess Konthoujam Tampha Lairembi saw smokes in her native place, she was restless. She came down to earth from heaven to find out who was dead. On reaching the place, her mother told her as follows:
Elephants in Meitei culture
In the Meitei epic of the Khamba and Thoibi, the crown prince Chingkhu Akhuba of ancient Moirang and Kongyamba, planned to kill to Khuman Khamba.
Kongyamba and his accomplices together threatened Khamba to give up Moirang Thoibi, which Khamba rejected. Then they fought, and Khamba bet all of them, and was about to kill Kongyamba, but the men that stood by, the friends of Kongyamba, dragged Khamba off, and bound him to the elephant of the crown prince, with ropes. Then they goaded the elephant, but the God Thangching stayed it so that it didn't move. Finally, Kongyamba lost patience. He pricked a spear to the elephant so that it moved in the pain. But it still didn't harm Khamba. Khamba seemed to be dead. Meanwhile, on the other hand, Goddess Panthoibi came in a dream to Thoibi and told her everything that was happening. So, Thoibi rushed to the spot and saved Khamba from the elephant torture.
Fishes in Meitei culture
Horses in Meitei culture
Lions in Meitei culture
Kanglā Shā
In Meitei mythology and religion, , also spelled as , is a guardian dragon lion, whose appearance is described as a creature with a lion's body and a dragon's head, and two horns. Besides being sacred to the Meitei cultural heritage,
it is frequently portrayed in the royal symbol of the Meitei royalties (Ningthouja dynasty).
The most popular iconographic colossal statues of the "Kangla Sa" stand inside the Kangla Fort in Imphal.
In Meitei traditional race competitions, winners of the race are declared only after symbolically touching the statue of the dragon "Kangla Sha". This ideology is clearly mentioned in the story of the marathon competition between Khuman Khamba and Nongban in the epic saga of Khamba and Thoibi of ancient Moirang.
Nongshāba
In Meitei religion mythology, Nongshaba () is a Lion God and a king of the gods. He produced light in the primordial universe and is often addressed as the "maker of the sun". He is worshipped by the Meitei people, specifically by those of the Ningthouja clans as well as the Moirang clans. He was worshipped by the Meitei people of Moirang clan as an ancestral lineage God.
He is the chief of all the in Ancient Kangleipak (early Manipur).
Pakhangba
In Meitei culture, Pakhangba is a very powerful dragon. He is known as a protector and ruler of the universe. He is a son to Mother Earth. Pakhangba is, no question, one of the most distinctive frightening dragons. He is known for having remote resemblances and equivalencies to Typhon of the Greeks, Bahamut of the Arabians, Nagas of the Hindus, and Quetzalcoatl of the Native Americans. His identity is the subject of numerous stories, some of which even combine him with significant historical figures.
Monkeys in Meitei culture
The Meitei folktale of , also known as the , is about the story of an old couple who were tricked by a gang of monkeys.
In the story, a childless old couple treat a group of monkeys, from the nearby forest kindly, like their own children. The monkeys give the old couple advice about planting taro in their kitchen garden. So, according to their suggestion, they boie the tubers in a pot until soft, then cooled them, wrapped them in banana leaves, and plant them in the garden. At midnight, the monkeys secretly steal and eat all the cooked taro and plant some inedible giant wild taro in their place. The next day, the old couple find the fully grown taro. They immediately cook and eat the full-grown taro and suffer an allergic reaction. Only after they take the hentak medicine is their allergy relieved. Realising they have been tricked, the old couple plan their revenge. So, the old man pretends to be dead, and the old woman cries out loudly so that the monkeys hear her. When the monkeys come and ask her what happened, she tells them that the old man died after eating the taro. She asks them to help her carry old man's body out to the lawn. As soon as the monkeys enter the housthe old man takes up his stick and beats them. Frightened, they all ran away. The old couple know that the monkeys will come back. So, they climb into the atticand hide. When the monkeys return a larger gang to take revenge, the attic breaks and falls on them, and they flee. Knowing that they might come back again, the old couple hide inside a large pot. When the monkeys come back, the couple farted continuously and the sound scares the monkeys, who flee and never return.
Pythons in Meitei culture
In Meitei mythology, Poubi Lai () was an ancient python. It lived in the deep waters of the Loktak Lake.
It is also referred to as the "Loch Ness Monster of Manipur".
Rodents in Meitei culture
In Meitei mythology, Shapi Leima (), is one of the three favorite daughters of the sky god and mistress and the queen of all rodents.
Tigers in Meitei culture
Tigers are among the most mentioned animals in different elements of Meitei culture.
Keibu Keioiba
In the Meitei mythology and folklore, Keibu Keioiba (), also known as Kabui Keioiba (), is a mythical creature with the head of a tiger and the body of a human. He is often described as half man and half tiger.
He was once a skilful priest named Kabui Salang Maiba. With his witchcraft, he transfigured himself into the form of a ferocious tiger. As a punishment of his pride (divine retribution), he could not completely turn back to his original human form.
Khoirentak tiger
In the Meitei folktale of the Khamba and Thoibi, Khuman Khamba and Nongban were in conflict regarding the affairs of princess Moirang Thoibi. Both men wanted to marry the princess. Among the two suitors, the princess had already chosen Khamba but still Nongban did not give up easily. The matter was set before the King of ancient Moirang in his court, and he ordered them to settle the matter by the trial by ordeal of the spear. However, an old woman said that there was a tiger in the forest hardby that attacked the people. So, the King chose the tiger hunt to be the witness and the ordeal. Whoever among the two that killed the tiger will get the Princess Thoibi as his wife. On the next day, the King and his ministers gathered there in stages. Many people gathered at the spot, that it seemed like a white cloth spread on the ground. Then the two went inside the forest. Near a dead body of a freshly killed girl, the tiger was found. Nongban tried to spear the tiger but he missed his target. Then the tiger sprang upon them and bit Nongban. Khamba wounded the beast, and drove it off. Then he carried Nongban to the gallery. Then Khamba entered the forest once again and found the tiger crouching in a hollow half hidden by the forest, but in full view of the gallery of the King.
Tiger of Goddess Panthoibi
Tortoises and turtles in Meitei culture
Tortoise/Turtle in the story of Sandrembi and Chaisra
In the Meitei folktale of Sandrembi and Chaisra, Sandrembi's mother transformed herself into a tortoise/turtle, after some time, she was killed by Sandrembi's stepmother, who was her cowife and rival. Upon being instructed in Sandrembi's dream, Sandrembi took the tortoise from the lake and kept it inside a pitcher for five consecutive days without any break. It was told to her that her mother could re-assume her human form from the tortoise form only if kept inside a pitcher for five consecutive days without any disturbance. However, before the completion of the five days, Chaisra discovered the tortoise and so, she insisted her mother to force Sandrembi to cook the tortoise meat for her. Poor Sandrembi was forced to boil her own mother in the tortoise form. Sandrembi tried to take away the fuel stick on hearing the tortoise mother's crying words of pain from the boiling pan/pot but she was forced to put the fuel in by her stepmother. Like this, Sandrembi could not save her tortoise mother from being killed.
See also
Hills and mountains in Meitei culture
Plants in Meitei culture
Birds in Meitei culture
Notes
References
Animals in art
Animals in culture
Animals in entertainment
Works about animals
Animals in mythology
Animals in popular culture
Animals in religion
Meitei culture
Meitei folklore
Meitei literature
Meitei mythology
Sanamahism | Animals in Meitei culture | [
"Biology"
] | 2,288 | [
"Animals",
"Works about animals"
] |
73,548,983 | https://en.wikipedia.org/wiki/Transition%20metal%20complexes%20of%20pyridine-N-oxides | Transition metal complexes of pyridine-N-oxides encompass coordination complexes that contain pyridine-N-oxides as ligands. Particularly common are the octahedral homoleptic complexes of the type where M = Mn(II), Fe(II), Co(II), Ni(II). Many variations of pyridine N-oxide are known, such as the dioxides of 2,2'- and 4,4'-2,2'-bipyridine. Complexes derived from the trioxide of terpyridine have been crystallized as well.
Structure and bonding
Pyridine-N-oxides bind to metals through the oxygen. According to X-ray crystallography, the M-O-N angle is approximately 130° in many of these complexes. As reflected by the pKa of 0.79 for , pyridine N-oxides are weakly basic ligands. Their complexes are generally high spin, hence they are kinetically labile.
Applications
Zinc pyrithione is a coordination complex of a sulfur-substituted pyridine-N-oxide. This zinc complex has useful fungistatic and bacteriostatic properties..
References
Amine oxides
Pyridinium compounds | Transition metal complexes of pyridine-N-oxides | [
"Chemistry"
] | 266 | [
"Amine oxides",
"Functional groups"
] |
73,549,670 | https://en.wikipedia.org/wiki/Nitrogen%20crisis%20in%20the%20Netherlands | The nitrogen crisis in the Netherlands () is an ecological and legal crisis that has been defined as such since 2019, following a ruling by the Administrative Jurisdiction Division of the Council of State.
Introduction
Around 78% of the earth's atmosphere is made up of gaseous nitrogen (). This naturally occurring gaseous form is fairly inert and does not pose an environmental problem. At the root of the nitrogen crisis is not but other more reactive nitrogen compounds that are the result of human impact on the nitrogen cycle. In the Netherlands, the soil is burdened by very high deposition rates of reactive nitrogen compounds, in particular ammonia (NH3) and nitrogen oxides (NOx). Ammonia is released into the air from animal manure, nitrogen oxides are emitted by internal combustion engines, such as those in motor vehicles, aircraft and industry. Nitrogen compounds from fertilizers used in agriculture are also washed directly into ground water. The presence of nitrogen compounds in large quantities is a form of nutrient pollution and adversely affects the quality of soil, water, air, and nature through the process of eutrophication.
The Netherlands emits more nitrogen compounds per hectare than any other country in the EU by a long way, according to the Netherlands Organisation for Applied Scientific Research. 61 percent of these nitrogen compounds are produced by agriculture, with intensive livestock farming being the most important source of nitrogen pollution. In a sense, the nitrogen crisis is the successor to the acid rain problem of the 1980s. Acid rain is caused by the deposition of ammonia and nitrogen oxides, but also sulfur dioxide (). From 1980 to 2020, the emission of sulfur dioxide was reduced by 80%. The emission of nitrogen compounds was also reduced by 50%. The emission of nitrogen dioxide (NO2) has been steadily decreasing ever since 1980. However, the reduction in the emission of ammonia came to a standstill around 2010, the last year of the fourth Balkenende cabinet.
In 2015, the Dutch government under the second Rutte cabinet launched a new program to reduce nitrogen pollution, the Integrated Approach to Nitrogen (, PAS).
History
2019 Court of State ruling
When the nitrogen crisis came to a head in 2019, it already had a long history, both legal and ecological. The first European standards were set as early as 1991. European Union member states are obliged to comply with the Habitats Directive, which states that a 'favourable conservation status' must be aimed for in Natura 2000 areas.
In May 2017, the Council of State submitted a number of preliminary questions to the European Court of Justice, which in November 2018 provided a further explanation of the relevant provisions of the Habitats Directive. On 29 May 2019, the Administrative Jurisdiction Division of the Council of State ruled on this basis that the government's use of the Integrated Approach to Nitrogen (PAS) was invalid when granting permits due to the anticipation of future reductions in nitrogen deposition. As a result, the PAS could no longer be used for granting nitrogen permits in the vicinity of Natura 2000 areas. This ruling led to the immediate suspension of various projects (mainly housing, which aggravated the ongoing Dutch housing shortage), and the government had to urgently seek solutions. Although nitrogen pollution had been an issue for many years, the Council of State's ruling promptly suspended an estimated 18,000 construction projects.
Later official recommendations and decisions
In June 2020, the Advisory Committee on the Nitrogen Problem under former Deputy Prime Minister Johan Remkes published a report titled ("Not Everything Is Possible Everywhere") which recommended reducing nationwide emissions of NH3 and NOx by 50% compared to 2019, for a long-term solution (up to 2030). The NH3 should be reduced even further in certain areas close to natural areas.
As of July 2021, construction projects could proceed without nitrogen testing under the so-called ("construction exemption"). However, this exemption was overturned by the Council of State in November 2022, and a "protracted nitrogen crisis" continues.
Protests and political developments
In the wake of the 2019 ruling and related government policies, a sizeable farmers' protest movement arose, which saw livestock farmers using tractors to block major Dutch roads and occupy public spaces.
In response to these protests, the agrarian and right-wing populist political party Farmer–Citizen Movement (, BBB) was founded in October 2019. In the 2021 general election, it argued for the creation of a "Ministry of the Countryside" () located at least 100 kilometers from The Hague and a removal of the ban on neonicotinoids. In addition, the party calls for right-to-farm laws, which would allow for farmers to have more say on expanding their agricultural activities, in response to local opposition to pig and goat farms over public health, environmental and agricultural concerns.
In 2023, the BBB received the most votes in the provincial elections and became the party with the largest number of seats in the Dutch Senate following the Senate election.
See also
Human impact on the nitrogen cycle
Environmental impact of agriculture
Environmental skepticism
Dutch manure crisis
References
Agriculture in the Netherlands
Environmental controversies
Environmental impact of agriculture
Environmental impact in the Netherlands
Intensive farming
Nitrogen | Nitrogen crisis in the Netherlands | [
"Chemistry"
] | 1,038 | [
"Eutrophication",
"Intensive farming"
] |
73,550,095 | https://en.wikipedia.org/wiki/Xerox%202700 | The Xerox 2700 is a discontinued monochrome laser printer from Xerox Corporation. The 2700 was announced in March, 1982, and can print up to 12 pages per minute (PPM), one-sided, on standard A4 or Letter cut-sheet paper. It occupies of floor space, and cost $18,995 (). The 2700 is rated for a print volume of 15,000 pages per month, although some users got up to 100,000 pages.
History
The first successful products based on the xerographic process were for office copying applications with direct optical imaging, but by about 1961 there were experiments under way at Xerox to explore other applications and imaging methods. In 1964, Xerox introduced LDX (Long Distance Xerography) a facsimile system which used a CRT (cathode ray tube) as an imaging source. A version for computer printing was offered as the XGP (Xerox Graphics Printer).
In 1973, The Xerox 1200, used an optical analogue of the drum line printer—a spinning optical character drum and a row of xenon tubes whose flashing was timed to project the required characters onto the xerographic photosensor. It was ingenious and unique. In 1977, Xerox introduced laser imaging for computer printing with the 9700 which was based on the 9200 copier and digital imaging technology from PARC.
Although the Xerox 8010 Star, introduced in 1981, was not a commercial success, one of the technologies it developed was the XP-12 marking engine for the Xerox 8044 printer, which became the basis for the 2700.
The 2700 was rebadged by Digital Equipment Corporation, who marketed it as the LN01.
Data stream
Conventional character printer protocols of the time used control characters and escape codes (the ESC character followed by another character) for formatting. Laser printing extensions required additional escape codes for functions like font changes and imbedded images. Xerox developed a page description language known as Xerox Escape Sequence (XES).
Specifications
The 2700 prints 12 pages per minute at 300x300 dots per inch(DPI). It has two 250-sheet
input paper cassettes, and a 500 sheet offsetting stacker to offset sections of output between print jobs or copy groups.
It uses an Intel 8086 CPU and an Intel 8089 coprocessor for input/output. It comes with 64 KB or 256 KB of RAM and 32 KB of ROM, with up to 4 32 KB in plug-in cartridges. The on-board ROM holds two font sets, portrait and landscape. The optional plug-in cartridges hold fonts and logos, and additional bitmaps can be downloaded.
The 2700 offers a variety of interface options. it provides serial Binary Synchronous (Bisync)—IBM 2770/2780/3780 emulation or asynchronous communications. It also supports parallel Centronics or Dataproducts emulation.
See also
Laser printing
References
Xerox
Laser printers
Office equipment
Computer-related introductions in 1982 | Xerox 2700 | [
"Technology"
] | 647 | [
"Computing stubs",
"Computer hardware stubs"
] |
73,551,111 | https://en.wikipedia.org/wiki/International%20Collection%20of%20%28Vesicular%29%20Arbuscular%20Mycorrhizal%20Fungi | The International Collection of (Vesicular) Arbuscular Mycorrhizal Fungi (INVAM) is the largest collection of living arbuscular mycorrhizal fungi (AMF) and includes Glomeromycotan species from 6 continents. Curators of INVAM acquire, grow, identify, and elucidate the biology, taxonomy, and ecology of a diversity AMF with the mission to expand availability and knowledge of these symbiotic fungi. Culturing AMF presents difficulty as these fungi are obligate biotrophs that must complete their life cycle while in association with their plant hosts, while resting spores outside of the host are vulnerable to predation and degradation. Curators of INVAM have thus developed methods to overcome these challenges to increase the availability of AMF spores. The inception of this living collection of germplasm occurred in the 1980s and it takes the form of fungi growing in association with plant symbionts in the greenhouse, with spores preserved in cold storage within their associated rhizosphere. AMF spores acquired from INVAM have been used extensively in both basic and applied research projects in the fields of ecology, evolutionary biology, agroecology, and in restoration. INVAM is umbrellaed under the Kansas Biological Survey at The University of Kansas, an R1 Research Institution. The Kansas Biological Survey is also home to the well-known organization Monarch Watch. INVAM is currently located within the tallgrass prairie ecoregion, and many collaborators and researchers associated with INVAM study the role of AMF in the mediation of prairie biodiversity. James Bever and Peggy Schultz are the Curator and Director of Operation team, with Elizabeth Koziol and Terra Lubin as Associate Curators.
History
INVAM was conceptualized and actualized by Dr. Norman Schenk, a mycologist and professor of plant pathology. In 1985, Schenk’s vision was funded by the National Science Foundation to begin the International Culture Collection Vesicular Arbuscular Mycorrhizal Fungi (INVAM). Schenk started INVAM at the University of Florida, and after his retirement in 1990, the collection moved to West Virginia University, where it merged with the collection maintained by Joe Morton. By 1990, Schenk’s collection included 182 accessions of 56 species, whereas Morton’s collection comprised 107 isolates and 49 species. The transition of Schenk’s collection from Florida to WVU presented challenges, as many cultures perished in transit. In the early years at WVU the focus of INVAM was to acquire and propagate more isolates and to improve propagation protocols. A reflection of this, the collection increased in size sixfold from 1995 to 2005. In 2021, the NSF funded the transition of INVAM to the University of Kansas, where it is under its current curatorship.
Evolutionary origins and ecological significance of AMF
Arbuscular (from arbuscula, Latin for “tiny tree”) mycorrhizal (“fungus-root”) fungi have ancient origins as plant symbionts. The earliest fossil evidence of a glomeromycete arbuscule, the site of plant-fungi exchange, is known from the Rhynie Chert, which dates to 407 million years ago, during the Lower Devonian. This early fossil arbuscule does not occur in a plant root, but instead occurs in the lateral axis of a now-extinct plant. Arbuscule-forming fungi thus potentially preceded the existence of roots, as roots likely evolved from rhizoid-based rooting systems during the Devonian (Kenrick 2014). Some researchers even suggest that roots evolved as habitats for fungi. There is support for the hypothesis that mycorrhizal fungi and roots have coevolved in various ways, and that Glomeromycotan fungi aided in the colonization of land by plants. AMF are known to associate with at least 80% of extant land plant species, and they may benefit their host plants in a variety of important ways, including, but not limited to, increase in phosphorus and nitrogen acquisition, increased biomass, resilience against drought stress, synergy with rhizobia partners, defense priming, and perhaps most contentious is AMFs ability to convey resistance to above-ground stressors such as herbivores. Specific AMF-plant relationships can fall on various points of a mutualistic-pathogenic spectrum, depending on the associated species in the partnership, and there is evidence that there could be significant differentiation in benefit conveyed when using native vs. commercially sourced inoculum. On a landscape-wide scale, AMF have the potential to accelerate succession and increase diversity in plant communities, increase soil stability through glomalin production by the mycorrhizae, and through development of mycorrhizal networks, they increase carbon storage in the soil, thus having global implications.
Scientific impact
The founder of INVAM, Dr. Norman Schenk, is coauthor of the book “Manual for the Identification of VA Mycorrhizal Fungi”, a refence that is still cited today in AMF taxonomic studies. This reference describes morphological characters of AMF genera, and descriptions of then-known species, which is still useful as identification of AMF species via DNA sequencing presents difficulty as each spore can yield many Operational Taxonomic Units (OTUs). In addition to overcoming the challenges presented by propagating and storing AMF, INVAM continues to play a role in the advancement of AMF identification technologies by providing correctly identified, diverse cultures for comparison when generating a sequenced database.
Dr. Joe Morton, second curator of INVAM, has played a role in classifying arbuscular mycorrhizal fungi, which is challenging considering both the difficulty in using DNA sequencing to differentiate between species, but also because arbuscular mycorrhizal fungi has only been known to reproduce asexually, so the well-used species concept, the Biological Species Concept (BSC), which defines a species as a group of organisms that produce fertile offspring when interbreeding, is difficult to apply.
INVAM has been cited as a resource in over 4000 scientific publications, as seen through Google Scholar.
Personnel of INVAM have aided in the establishment of other AMF culture collections in Europe with The International Bank for the Glomeromycota, South America with the International Culture Collection of Glomeromycota, and other collections in South Africa, Taiwan, and China.
References
Herbaria in the United States
Mycology organizations
Soil biology | International Collection of (Vesicular) Arbuscular Mycorrhizal Fungi | [
"Biology"
] | 1,364 | [
"Soil biology"
] |
73,551,502 | https://en.wikipedia.org/wiki/Elizabeth%20Cottrell | Elizabeth Stevenson (professionally Elizabeth Cottrell; born 1975) is a geologist and museum curator for the National Museum of Natural History. She is a fellow of both the Geochemical Society and the Mineralogical Society of America.
Early life and education
Born in 1975, Cottrell grew up in northern Vermont. Her father was an engineer. In 1997, Cottrell received a Bachelor of Science in geochemistry from Brown University. She went on to earn a Ph.D. in environmental science from Columbia University in 2004.
Career
Cottrell has been a visiting scientist to the Carnegie Institute, as well as a Fulbright Scholar.
The focus area of Cottrell's research is largely in Alaska and Oceania, though she works out of Washington, D.C. She has also worked as a visiting scientist to ClerVolc from Clermont Auvergne University. She is best known for her work in the geologic fields of mineralogy and volcanism, especially as it relates to the geochronology of the Earth. She currently works as the curator-in-charge of rocks and ores for the National Museum of Natural History, and as the chair of the museum's department of mineral sciences.
Cottrell's career at the Smithsonian Institution has also involved her serving as director of the Global Volcanism Program from 2010 to 2016. She was also a co-director of the NSF Natural Resources REU from 2010 to 2022. Being an employee of the Smithsonian Institution, she is often featured in the Smithsonian magazine as a geology expert. She has also appeared in other Smithsonian publications and media posts.
The Doctor Is In
Cottrell is the host of the second season of The Doctor Is In, a video series produced by the Smithsonian Institution.
References
External links
American women curators
American mineralogists
Women mineralogists
Women geochemists
American geochemists
American volcanologists
Living people
1975 births
Place of birth missing (living people)
Scientists from Vermont
Brown University alumni
Columbia University alumni
University of Maryland, College Park faculty
Smithsonian Institution people
Fellows of the Mineralogical Society of America | Elizabeth Cottrell | [
"Chemistry"
] | 423 | [
"Geochemists",
"Women geochemists",
"American geochemists"
] |
73,554,301 | https://en.wikipedia.org/wiki/Argyroxiphium%20sandwicense%20subsp.%20macrocephalum%20x%20Dubautia%20menziesii | Argyroxiphium sandwicense subsp. macrocephalum x Dubautia menziesii, commonly known as the Dubautia-silversword, is a hybrid species of silversword plant in the family Asteraceae, and is a part of the silversword alliance. The hybrid was formed between Argyroxiphium sandwicense subsp. macrocephalum and Dubautia menziesii, which are both species of plant native to the Haleakalā Shield Volcano, Maui, primarily in the Haleakalā Crater, that grow in alpine and subalpine zones.
References
sandwicense subsp. macrocephalum x Dubautia menziesii
Endemic flora of Hawaii
Biota of Maui
Haleakalā National Park
Hybrid plants
Dubautia | Argyroxiphium sandwicense subsp. macrocephalum x Dubautia menziesii | [
"Biology"
] | 165 | [
"Hybrid plants",
"Plants",
"Hybrid organisms"
] |
73,554,993 | https://en.wikipedia.org/wiki/Ligand-targeted%20liposome | A ligand-targeted liposome (LTL) is a nanocarrier with specific ligands attached to its surface to enhance localization for targeted drug delivery. The targeting ability of LTLs enhances cellular localization and uptake of these liposomes for therapeutic or diagnostic purposes. LTLs have the potential to enhance drug delivery by decreasing peripheral systemic toxicity, increasing in vivo drug stability, enhancing cellular uptake, and increasing efficiency for chemotherapeutics and other applications.
Liposomes are beneficial in therapeutic manufacturing because of low batch-to-batch variability, easy synthesis, favorable scalability, and strong biocompatibility. Ligand-targeting technology enhances liposomes by adding targeting properties for directed drug delivery.
Ligand selection
Ligands are molecules responsible for binding to receptors in the cellular targeting process. Surface-coupled ligands offer a greater degree of freedom to move on the liposome membrane for optimal interactions.
Ligands are typically monoclonal antibodies (mAbs) or antibody fragments, but can also include other molecules such as ARPG, proteins, peptides, vitamins, carbohydrates, and glycoproteins. The choice of ligand can significantly influence the behavioral and functional properties of a ligand-targeted liposome. Antibody fragments have lower immunogenicity and improved pharmacokinetics. mAbs are unique and can be used for inhibition of DNA repair, terminating the cell cycle, and triggering apoptosis, all of which factor into applications for anticancer drugs. Peptides are relatively easy and affordable to prepare with low antigenicity and lower opsonization, which are thus more resistant to enzymatic degradation. Proteins can target the transferrin receptor membrane glycoprotein. Sugars and vitamins are recognized by cellular transport receptors.
Ligand choice is based on receptor expression, ligand internalization, binding affinity, and type of ligand. Ligands alone are not able to carry an efficient payload for therapeutic levels but can carry more of the agent when combined with liposomes.
Ligand attachment to liposome
Ligands can be attached to liposomes through ligation to create ligand-targeted liposomes in a variety of ways. Liposomes have a lipid outer layer that can be used to bind ligands. Conjugation of the ligand to the surface of a liposome can be achieved through multiple routes. Covalent binding is a prominent way due to the anchoring between the long-chain fatty acids and the ligand. Combinations of covalent binding through disulfide linkages, heating, and hydrophobic interactions can be used depending on the properties of the liposome and ligand. Adsorption and membrane fusion are non-covalent methods for the attachment of monoclonal antibodies. Chemical linkages such as covalent bonds are more effective at increasing the amount of attached ligand to the carrier as opposed to non-covalent methods.
During chemical coupling for manufacturing, it is crucial that ligands maintain their integrity when attached to the liposome surface. If ligands, such as antibodies, do not maintain binding specificity, proper orientation, and coupling efficiency, the liposome will not be effective.
Cellular interaction and delivery of contained agent
Since the ligand is responsible for cellular interaction, it is chosen for the application depending on the target site. The target site contains binding sites that the ligand targets to deliver the LTL to the desired area. Favorable target site characteristics are determined by what is commonly expressed by tissues of the pathology of interest. Determinants can include histones, basement membrane fibrinogen, selectins, adhesion molecules, and other ligand targets. For example, in some human cancer tumors such as ovarian carcinomas, folate is over-expressed. LTLs for targeting cancer often use a ligand that targets this over-expression of folate to localize drug delivery to the desired area. The tumor microenvironment of solid tumor cancers is also a unique targeting site. Tumor endothelial cells are important for angiogenesis, which is key to tumor growth; therefore, using LTLs to target these cells can limit the growth and vascularization of a tumor.
Ligand-targeted liposomes utilize active targeting to interact with the desired cells. Once administered intravenously into blood circulation, ligand-targeted liposomes must travel to reach the target area to deliver their contents. LTLs retain the contained agent until the process of cellular uptake.
Receptor-mediated endocytosis is the most common way LTLs deliver material to the cell. The targeting ligand connected to the liposome attaches to the binding site found on the targeted cell. The LTL's contents are transported to Lysosomes to be processed. This process allows the molecules to cross the blood-brain barrier, which allows the drug to be delivered to tissue that is relatively difficult to reach without a specific mechanism. Less commonly, pinocytosis or phagocytosis may be used for cellular uptake of the liposome. Certain recognition sites, such as ecto-NAD+oglycohydro|ase, mediate uptake to aid in the internalization and effectiveness of the LTLs.
The remainder of LTLs in circulation after binding to the target site are mainly cleared through the reticuloendothelial system (RES). The RES includes different organs including the kidneys, lungs, spleen, liver, bone marrow, and lymph nodes. The liver is the primary organ for the clearance of LTLs. The RES is most likely able to clear LTLs due to fenestrations in their microvasculature that allow for extravasation. Phagocytic cells within the RES break down LTLs.
Applications of LTLs in medicine
Ligand-targeted liposomes are used for a variety of applications depending on the liposome, ligand, and liposome contents.
Ligand-targeted liposomes can be used for diagnostics through imaging. The liposomes can contain imaging agents to aid in visualization such as fluorescent dyes, labeling probes, and contrast agents. Commonly, a radioactive gamma-emitter, fluorescent marker, or magnetic resonance imaging (MRI) agent is encapsulated in the liposome for this application. The active targeting mechanism of LTLs allows the target tissue to retain the imaging agent while the remaining agent is cleared from circulation. The ligand-targeted liposomes increase the specificity and sensitivity of the images taken through positron emission tomography (PET), single-photon emission computed tomography (SPECT), and MRI techniques through the ligand localization to receptors of interest. Biotinylated liposomes containing [67Ga] coupled with a later injection of avidin have been shown to reduce background signal and produce the needed contrast for imaging while reducing the circulation time of radioactive imaging agent. Molecular imaging of processes over time in vivo is also made possible using ligand-targeted nanoparticles. As of 2015, many ligand-targeted imaging agents such as MIP-1404, MIP-1405, MIP-1072, MIP-109, and 18F-DCFBC were undergoing clinical trials. The ability of a liposome to encapsulate these imaging agents and deliver them to specific regions through ligand targeting is helpful for precision detection.
Ligand-targeted liposomes are a promising method of drug delivery. These systems are efficient in delivering the drug to localized areas with low peripheral distribution, which minimizes off-target effects. The favorable biodistribution to target tissue is an encouraging property of this drug delivery system. In addition to highly targeting tissue, LTLs have a short circulating half-life, so they can be quickly cleared from the bloodstream. LTLs can be used to deliver AuNRs for localized delivery of photo-thermal therapy in cancer treatment. Photodynamic therapy (PDT) is a non-invasive cancer therapy that relies on a photosensitizing (PS) pro-drug to interact with light and oxygen as a cancer therapeutic agent. PSs can be encapsulated in LTLs—allowing them to move through systemic circulation to the tumor site for ligand binding—to specify the area of their effect. Using PDT causes damage to cancer cells and tumor microvasculature. There are many liposome-based products currently approved or undergoing clinical trials.
Aside from cancer therapies, ligand-targeted liposomes can also be used to target inflammation in the body that may be present due to rheumatoid arthritis, psoriasis, vascular inflammation, and organ transplantation. E-selectin is a cell-specific receptor expressed by inflamed endothelium that ligands can target.
LTLs also have the potential for localized treatment in fungal infections. AmBisome (L-AMB) is an LTL that contains Amphotericin B (AMPH-B), an anti-fungal treatment that is effective for a broad variety of fungal infections. AMPH-B can be toxic after prolonged exposure, making it a good candidate for the targeting and rapid clearing of systemic circulation of LTLs. AmBisome is also effective due to the inflammation in the area of fungal activity, which increases vascular permeation.
Disadvantages
Consistently producing ligand-targeted liposomes through traditional methods is difficult. The process can be tedious, challenging to control and result in a poorly defined system. Using the 'post-insertion' technique—in which Micelles formed from PEG-linked ligands are incubated with pre-formed, drug-loaded, non-targeted liposomes to combine and form LTLs—can limit the associated manufacturing challenges.
When using certain ligands, such as antibodies, the risk for an immunological reaction poses a risk. Liposome design including size, charge, morphology, composition, surface characteristics, and dose size can all influence the immune response to administered LTLs. The ligands used can elicit an immune response when introduced into the body. For example, when peptide ligands such as CDX are used for brain-targeted delivery systems, they are immunogenic and trigger an immune response. Complement Activation-Related Pseudo-allergies (CARPA) is a hypersensitivity syndrome that can be triggered when LTLs activate the innate immune system and the complement system. CARPA can cause many side effects including anaphylaxis, cardiopulmonary distress, and facial swelling. These side effects have the potential to be severe, which generates concern when administering LTLs to patients with health problems, especially cardiovascular issues. This reaction can be reduced by slowing infusion rates or incorporating the use of allergy medicines like antihistamines into the treatment regimen.
Due to the immune response, LTLs can experience the accelerated blood clearance (ABC) phenomenon. This phenomenon is more common in repeated dosage usage of LTLs, such as multi-dose PEGylated formulas, because of immunological memory. The pharmokinetics and clearance rates of the second dose have been shown to be significantly reduced while accumulation in the spleen and liver increases. This poses challenges for clinical applications of LTLs that require multiple doses to be effective.
Ligand-targeted liposomes need specific conditions to remain intact for use. Controlling environmental factors such as temperature and pH is necessary to maintain the integrity of the molecules. This can be helpful for temperature-sensitive or pH-dependent drug release conditions but is harmful if the pH changes at an inopportune time. This technology can also be used in combination with enzymes such as in Gal-Dox, which releases active doxorubicin in combination with β-Galactosidase. Making sure the compound does not encounter the enzyme too early is also important for effective usage.
There is a possibility that LTLs lead to immunosuppression. LTLs are cleared through the RES which is part of the innate immune system. Macrophage saturation to remove the liposomes could impact the ability of the phagocytic cells to function properly to conduct immune functions. Significant immune suppression has not been observed in clinical cases for therapeutic doses of LTLs containing non-cytotoxic drugs.
References
Medicinal chemistry | Ligand-targeted liposome | [
"Chemistry",
"Biology"
] | 2,514 | [
"Biochemistry",
"nan",
"Medicinal chemistry"
] |
73,555,371 | https://en.wikipedia.org/wiki/Waiwhetu%20Aquifer | The Waiwhetu artesian aquifer, sometimes referred to as the Hutt aquifer, is a pressurized zone of water-retaining sand, gravel and boulders beneath the Hutt Valley and Wellington Harbour in New Zealand. The aquifer provides about 40% of the public fresh water supply for Lower Hutt and Wellington city. Water from the Hutt River begins to flow underground south from Taita Gorge, then becomes pressurized under a seal of clay. Water is extracted from the pressurized area for public use, but concerns about overuse and damage by earthquakes have led to investigations of alternative sources of fresh water.
Formation and location
The Waiwhetu aquifer covers a wedge-shaped area of 75 km² under the Hutt Valley and Wellington Harbour, and by size is the fifth-largest in New Zealand.
The harbour basin contains massive quantities of gravel washed down from the Hutt River, in some places hundreds of metres deep. Above the gravel is a layer of mud and silt which seals fresh water within the gravel, creating an artesian aquifer. There are several aquifers in the area in different layers underground, but the Waiwhetu aquifer is the largest and most productive one. Water flows down into the aquifer from a five-kilometre stretch of the Hutt River south of Taita Gorge, at the rate of 1000 litres per second. Rainwater also contributes to the aquifer. South of Melling the aquifer becomes pressurized by the layer of mud and silt above the gravel layer holding the water in, meaning that if a bore is sunk into the aquifer, water will rise up the pipe.
Water from the aquifer also reaches the surface through natural springs at various places around the harbour. In 2023, NIWA released the results of a project investigating the harbour floor. Instead of drilling, researchers used a combination of techniques including seawater sampling, acoustic measurements, visual observation via remote operated vehicles and sea floor sampling. Researchers discovered that the seafloor contains hundreds of depressions, known as 'pockmarks'. These vary in size from three metres to over wide and up to deep, and are the source of several hundred freshwater springs. Comparing the new data to previous studies, researchers determined that the pockmarks are long-lasting rather than temporary features.
Pressure within the aquifer stops sea water from getting into the aquifer. Once in the aquifer, the water moves slowly. It takes several years for water in the underground aquifer to reach Waterloo from the Taita Gorge, about 10 years to reach the Petone foreshore and 20 years to get as far as Matiu / Somes Island. The water level in Wellington Harbour was much lower 20,000 years ago, and the ancient Hutt River used to flow down a paleochannel to the east of Matiu / Somes Island as far as the present-day Miramar Peninsula. Much of the water in the Waiwhetu aquifer moves under the sea bed from the direction of the Hutt River to the Falcon Shoals area (between Karaka Bay and Worser Bay) at the harbour mouth via the paleochannel. The characteristics of the aquifer between Matiu / Somes Island and the harbour mouth are not as well studied as the portion to the north of the island. NIWA's 2023 study stated that the southern limit of the aquifer is still debatable, but thought to be around the Falcon Shoals.
Extraction
Wellington Water manages the water supply for Wellington and the Hutt Valley. The Waiwhetu aquifer provides water to 150,000 people in Wellington and Hutt City. This is around 40 percent of the Wellington region's annual water supply, and up to 70 percent in summer months.
From the 1880s, residents and businesses in the Hutt Valley and Petone area sank wells into the aquifer for fresh water, and in 1908 Lower Hutt Borough introduced a public water supply fed from artesian bores. Wellington and Lower Hutt also built dams and used water taken from rivers. Over the years, bores and pumping stations have been installed in various areas in the Hutt Valley. For example, a bore field and pumping station were built near Hutt Park in 1946-47. This closed in 1981 after Waterloo was built. Another pumping station was built at Buick Street in Petone in 1963 after water supply from the Korokoro Stream deteriorated. It was shut down in 1999.
Gear Island
After several years of negotiations in the 1930s between the councils of Lower Hutt, Petone and Wellington, Wellington City Council gained the right to sink bores and build a pumping station at Gear Island. Gear Island pumping station opened in 1936, sending artesian water into a water main that also brought water from the Orongorongo River in Wainuiomata to Wellington city. Water from Gear Island was only used infrequently, to supplement Wellington's supply in periods of high demand. Gear Island was upgraded in 1976-77, served by three new bores on the Shandon Golf Course. Fluoridation was also introduced at that time. Since 1999, Gear Island has been maintained as a standby plant, run occasionally to maintain its operational status in case it is needed.
Waterloo
The Waterloo pumping station opened in 1981. In the 1980s, eight bores drawing from the aquifer were put in along Knights Road and nearby streets in Lower Hutt (known as the 'Knights Road spine'), and these feed into the Waterloo pumping station for treatment and public distribution as drinking water. The Waterloo plant serves Hutt Central, Naenae, the Western Hills, Eastbourne, Gracefield and Petone. Water is also sent into the main from Wainuiomata that goes via Gear Island to Wellington.
Other bores
There is a bore at Hutt Hospital for use in emergencies. Other bores into the aquifer are used mainly for industrial purposes. A 2014 report identified 13 private bores in the Hutt Valley and Petone area, five of which had consents to take 1,000 cubic metres or more of water from the aquifer each day.At the time of its sale in 2014, the Unilever soap factory in Petone had consent to take 900,000 cubic metres of water from the aquifer each year.
In 2017, Hutt City Council granted Waiwhetu Marae $150,000 to install a bore, and the bore was opened for use in 2020. This bore is unchlorinated, but treated with UV light.
Two other bores provide free unchlorinated water from the aquifer direct to the public. One is at the Dowse Art Museum in Lower Hutt, where a small park with a water feature was created in 2012, and the other is Te Puna Wai Ora (Spring of Life) in Buick Street, Petone, built in 2003.
Moore Wilson's produce store in Wellington has an artesian bore that provided water to the public. It closed temporarily in 2017, after arsenic was detected in the water. Water in this bore comes from about 152 m deep, and the company states that it is believed to come from the Wairarapa. It is not connected to the Waiwhetu aquifer.
Water treatment
Lime is added to aquifer water coming in to the Waterloo station, to adjust its pH level so that the pipes are not damaged. Apart from this, prior to 2016, water from the aquifer was not treated because its long period filtering underground meant the water was free from bacteria and viruses. Water from the aquifer going to Wellington (but not the Hutt) was treated with chlorine as it mixed with chlorinated water coming from Wainuiomata and passed through the Gear Island pumping station. Water from the aquifer going to 74,000 people in Petone, Hutt Central, Naenae and Eastbourne was not chlorinated.
In August 2016 there was a major outbreak of gastroenteritis in Havelock North caused by public water supply contamination. As a precautionary measure, Wellington Water responded by changing its regime of water testing from the Waiwhetu aquifer. On 1 December 2016, routine testing of water from a bore on the Knights Road spine showed contamination with e. coli, the first time since 1980 that a positive test had occurred. The water supply was temporarily chlorinated while further tests were carried out. It was suspected that the contamination was a result of ground disturbance caused by the Kaikōura earthquake on 14 November, but an investigation by Wellington Water did not reach a firm conclusion. Tests at other bore locations in February and April 2017 also returned results positive for e. coli. After comprehensive testing and investigation, Greater Wellington Regional Council decided to continue chlorination permanently and install UV filters at the Waterloo plant.
In April 2017 the unchlorinated bore supply available to the public at Te Puna Wai Ora and the Dowse Art Museum were shut down after returning positive results. These were reopened to the public after a system of filtering the water and treating it with UV light was installed.
A new pipe system for water diversion was also installed along Knights Road, through Lower Hutt to the harbour, completed by the end of 2017. The project won an award from Civil Contractors NZ Wellington/Wairarapa.
Protection
Water pressure within the aquifer keeps sea water out, but the pressure can drop due to too much water being extracted, or due to less water in the aquifer in dry spells when the Hutt River and rainfall are low. If the pressure drops then sea water may get into the aquifer via vents on the harbour floor. This is known as saline intrusion, and could make water in the aquifer undrinkable. Greater Wellington Regional Council controls the amount of water extracted and monitors the level of water in the aquifer (and therefore the pressure) with three bores on the Petone foreshore, and others further inland in the Hutt Valley. If the water level drops, extraction can be reduced. There are three warning levels. The first warning level (2.5 metres above mean sea level) is reached regularly during summer. Water has fallen to the second level (2.3 metres above mean sea level) for short periods several times since 2002, and in March 2016 water in the aquifer briefly got as low as the third level (2 metres above mean sea level). Matiu / Somes Island gets its fresh water from a bore sunk into the aquifer just off shore at the main wharf. In February 2016 the Department of Conservation temporarily restricted visitor access to the island because the long dry summer had lowered the volume and pressure of water in the aquifer, necessitating strict water conservation. The lowest recorded water level in the aquifer occurred in the summer of 1973, when the water level sank to 1.19m above mean sea level and sea water started to enter the aquifer.
Apart from the risk that over-extraction could lower the pressure in the aquifer and cause saline intrusion, other activities which threaten the aquifer include accidental piercing of the aquifer, dredging and disturbances to the sea floor caused by shipping movements. For example, in 1929, workers driving piles for a wharf at Point Howard pierced the aquifer, causing a large spring to form. The spring was so strong that a diver sent to investigate had trouble approaching the hole. Dredging activities at the mouth of the Hutt River in 1937 caused a severe drop in pressure in the aquifer throughout the Hutt Valley. Pressure was restored by filling the hole made by the dredging with excavated material, and with material carried down the river by flooding. In 2000, a study of the aquifer raised the possibility that the Lynx, a fast ferry, was disturbing the sea bed near the Falcon Shoals and thus causing water to leak from the aquifer. In 2015 CentrePort, which manages shipping in the harbour, proposed to dredge a 7km-long channel at the mouth of the harbour to enable large container ships to visit. This might have affected the aquifer. The project was later cancelled.
Future proofing
Responding to the November 2016 Kaikōura earthquake, in 2017 Wellington Water began a project drilling into the harbour bed to look for fresh water that might supply the city in an emergency. After exploratory drilling, two bores were drilled into the Waiwhetu aquifer and the Moera aquifer which lies in a deeper layer below it. The first bore was put in about 800 metres from the Miramar peninsula, and the second was about halfway between the peninsula and Eastbourne, to the south of Matiu / Somes Island. Although fresh water was found, the investigation concluded that the quantity and quality of the water was not suitable for an emergency supply for Wellington. Instead, a cross-harbour pipeline became the preferred option.
See also
Water supply and sanitation in the Wellington region
Water supply in the Wellington region
Wellington Water
Water services reform programme
References
External links
Waiwhetū Aquifer at Greater Wellington Regional Council
Waiwhetu Aquifer discussed on RNZ 29 August 2023
Waiwhetu Aquifer discussed in extended interview on RNZ 31 August 2023
Water supply and sanitation in New Zealand
Wellington Region
Aquifers
Landforms of the Wellington Region | Waiwhetu Aquifer | [
"Environmental_science"
] | 2,756 | [
"Hydrology",
"Aquifers"
] |
73,555,762 | https://en.wikipedia.org/wiki/Plop%20Boot%20Manager | The Plop Boot Manager is a proprietary bootloader written by Elmar Hanlhofer. Plop Boot Manager can make computers boot from media that the original BIOS has no support for, such as USB or IDE CD/DVDs. Optionally, Plop can be installed directly onto the hard disk of a computer.
References
External links
Boot loaders | Plop Boot Manager | [
"Technology"
] | 74 | [
"Computing stubs",
"Software stubs"
] |
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