text stringlengths 11 1.65k | source stringlengths 38 44 |
|---|---|
Electroconductive carbon black Made up of primary carbon, carbon black is spherical in shape and arranged into aggregates and agglomerates. It differs from other carbon forms (diamond, graphite, coke) in its complex configuration, colloid dimensions and quasi-graphitic structure. Carbon black's purity and composition are practically free of inorganic pollutants and extractable organic substances. A distinction is made between these two terms: Carbon black can be characterized as a substance with over 97% amorphous carbon content. It is used extensively in many areas of industrial chemistry. It is often used in the plastic and rubber manufacturing industries, where it improves electrical conductivity and electromagnetic or thermo-conductive characteristics of plastic materials and rubbers. By virtue of its pigmentation capabilities, it is also used for the production of special printing inks, paints and varnishes. Thanks to its advanced porous structure, it is also used as a catalyst carrier, and its notable sorption attributes are utilized for, in example, catching gaseous pollutants at waste incinerator plants. Carbon black predominantly includes a conductive type of carbon, which combines an extremely high specific surface and extensively developed structure – microporosity. At the same time, it consists of primary carbon particles and boasts a high degree of aggregation. Carbon black's grouping facilitates the formation of a conductive structure in plastics, rubbers and other composites | https://en.wikipedia.org/wiki?curid=59891440 |
Electroconductive carbon black These characteristics predetermine electroconductive carbon black's primary area of application, i.e. electrical conductivity modification of nearly all types of plastic materials by adding a relatively low volume of carbon black. Such modifications can be utilized for numerous purposes, from establishing antistatic properties to adjusting polymer conductivity. Another valuable property of electroconductive carbon black is its excellent ability to absorb UV radiation on the visible spectrum, i.e. as a UV stabilizer for plastic materials, pigment in printer inks, paints and varnishes, or for coloring plastics, rubbers and sealants. Carbon black begins as a byproduct of what is referred to as partial oxidation, a process during which crude oil residues, such as vacuum residues from crude oil distillation or residues from the thermic cracking process, split due to the effects of the mixture of oxygen and water steam under high temperatures around 1,300 °C. Partial oxidation of various raw materials always creates a gaseous mixture containing CO, CO2, H2O, H2, CH4 and H2S and COS formed from sulfurous compounds. Carbon black is formed as an undesired byproduct. The amount of carbon black grows as the injection's molecular weight increases. Methane gasification produces approx. 0.02% mass, crude oil residue gasification approx. 1-3% mass. During the respective process, carbon black is captured into water through the method of scrubbing, thus creating carbon black water | https://en.wikipedia.org/wiki?curid=59891440 |
Electroconductive carbon black The generated carbon black water with 7–15 g/l of carbon black is further processed at the production facility into several types of carbonaceous substrates. The main production principle lies in isolating carbon from the water using granulation petrol, where intensive homogenization causes the carbon to transform from its aqueous to an organic phase, i.e. transformation of the water-carbon suspension to petrol-carbon suspension in the form of carbonaceous granules. The carbonaceous granules are subsequently processed into a finished product – carbonaceous substrate. The two mediums’ proportionality primarily depends on carbon content and physical and chemical properties of the carbon black water and granulation petrol. Carbon black is essentially formed out of primary carbon, but its structure is much less arranged than that of, for example, graphite. Carbon black exists in the form of discrete particles, however, during the production process its spherical particles, also called primary particles, cluster (aggregate) into chains or clusters. These aggregates then form the smallest carbon black units. They define what is known as the primary structure. Primary structure is characterized by the following: size of the primary particles, surface size, size and structure of the aggregates or chemical “composition” of the carbon black surface. These characteristics determine other carbon black features, such as adsorption properties, density, electrical conductivity, and absorption of UV radiation or visible light | https://en.wikipedia.org/wiki?curid=59891440 |
Electroconductive carbon black The most important characteristic of carbon black is the size of its primary particles and the related surface area. The size of the primary particles describes the size of individual spherical particles that form a primary structure. The size of individual particles is determined using an electron microscope. It has been ascertained that the smaller the particles, the greater the size of their surface. Carbon black particle size is between 10 and 100 nm, while the surface particle size is between 20 and 1,500 m/g. Generally speaking, small carbon black particles with a high surface area are darker, have higher viscosity and lower wettability, are harder to disperse, retain greater conductivity and absorb UV radiation well. Another significant characteristic of carbon black is its structure and the size of its aggregates. The size and complexity of the aggregate structure is determined by the volume of the carbon black spherical primary particles, which cluster together during the production process. The highly complex carbon black structure consists of branched chains with many secondarily created spaces in the aggregate. On the other hand, aggregate structure that is developed only a little represents smaller clusters of the spherical particles and thus also smaller spaces inside of the aggregate. The aggregate structure does not depend on the size of the particles. It has been established that particles of the same size can have aggregates with completely different structures | https://en.wikipedia.org/wiki?curid=59891440 |
Electroconductive carbon black Generally speaking, carbon black that has a highly developed and complex structure is easier to disperse, has lower wettability, higher electric conductivity and higher viscosity. Yet another noteworthy characteristic is carbon black's chemical surface composition. Chemisorbed complexes containing oxygen, such as carboxylic, quinonic or phenolic groups appear on carbon black surfaces. These groups, which contain oxygen, can significantly affect chemical reactivity, wettability, carbon black catalytic characteristics, electric conductivity, etc. "Picture: Diagram of carbon black structure and texture creation" "Composite applications" Some of the world's main producers of electroconductive carbon black include UNIPETROL (Chezacarb), CABOT Corporation (Vulcan), DEGUSSA (Printex), AKZO-Nobel (Ketjenblack), TIMCAL (Ensaco), BIRLA CARBON (Conductex), ORION ENGINEERED CARBONS (XPB). | https://en.wikipedia.org/wiki?curid=59891440 |
NGC 5201 is a spiral galaxy located in the constellation Ursa Major. It was discovered on April 14, 1789 by German-born British astronomer William Herschel. It is about 384 million light years away. | https://en.wikipedia.org/wiki?curid=59901942 |
Rupert Sutherland (born 1967) is a New Zealand geologist and academic specializing in tectonics and geophysics at the Victoria University of Wellington and a principal scientist at GNS Science. Sutherland has been described as "one of New Zealand’s leading earth science researchers" by the Royal Society of New Zealand. Sutherland completed his BA with honours from the University of Cambridge in 1989. His PhD at the University of Otago in 1995 was on the development of the Alpine Fault. Sutherland's research has included the deep ocean drilling of the Zealandian continent and ancient climate change. He has identified and named the ancient Moa tectonic plate. He is a co-leader of the Deep Fault Drilling Project (DFDP) of the Alpine Fault. As a result of this project, exceptionally high heat flow was discovered on the West Coast. Sutherland was the lead author reporting this in "Nature". Sutherland is often used by the national and international media as an expert on seismic surveys, earthquakes and geology in general. His involvement of the promotion of Zealandia to a continent gained a particularly high amount of media attention. | https://en.wikipedia.org/wiki?curid=59927248 |
DNA‐templated organic synthesis (DTS) is a way to control the reactivity of synthetic molecules by using nature's molarity‐based approach. Hostorically, DTS was used as a model of prebiotic nucleic acid replication. Now however, it is capable of translating DNA sequences into complex small‐molecule and polymer products of multistep organic synthesis. The DNA base editors, developed at Harvard University under David Liu, allow altering the genomic structure of DNA. The base editors include BE3, BE4 and ABE7. BE3 (and its later version, BE4) allow to change the nucleobase C to T and nucleobase G to A. ABE7 allows to change A-T base pairs into G-C base pairs. The system works by rearranging the atoms in the target base pair and then tricking cells into fixing the other DNA strand to make the change permanent. | https://en.wikipedia.org/wiki?curid=59953471 |
Mineral variety In geology and mineralogy, a mineral variety is a subset of a mineral species or mineraloid with some special characteristic, such as specific impurities or structural defects. For example, amethyst is a variety of quartz with a purple tinge due in part to iron impurities. Mineral varieties can be further subdivided into sub-varieties. Unlike mineral species, mineral varieties are not defined or named by the International Mineralogical Association (IMA). | https://en.wikipedia.org/wiki?curid=59961522 |
Mineral group In geology and mineralogy, a mineral group is a set of mineral species with essentially the same crystal structure and composed of chemically similar elements. For example, the amphibole group consists of 15 or more mineral species, most of them with the general unit formula , where A is a trivalent cation such as or , B is a divalent cation such as , , or , and C is an alkali metal cation such as , , or . In all these minerals, the anions consist mainly of groups of four tetrahedra connected by shared oxygen corners so as to form a double chain of fused six-member rings. In some of the species, aluminum may replace some silicon atoms in the backbone, with extra B or C cations to balance the charges. | https://en.wikipedia.org/wiki?curid=59961778 |
River Styles Framework The is a scientific tool used to describe and explain the diversity and distribution of river types in a catchment according to river character and behaviour. The is based on the science of fluvial geomorphology. Each river type is called a "River Style" and its name is constructed following a consistent naming convention. The provides an open-ended process for interpreting rivers rather than fitting them into pre-existing categories. The is designed to provide a scientific basis for river management. It was developed by researchers at Macquarie University. The was developed by Gary Brierley and Kirstie Fryirs at Macquarie University. The first peer reviewed paper on River Styles was published in 2000. Initial research that helped to develop the was funded by Land & Water Australia and New South Wales Department of Land and Water Conservation. The has four stages of analysis, which provide a framework to describe river character, explain how the river behaves and predict how a river may adjust its form in the future. The following overview of the stages is sourced from the book,""Geomorphology and River Management: Application of the River Styles Framework"". Stage 1 provides a baseline survey of a river's character and behaviour. Steps in Stage 1 include: Stage 2 assesses and explains geomorphic river condition throughout a catchment. River condition is a determination of environmental quality pertaining to a river's geomorphology | https://en.wikipedia.org/wiki?curid=59969032 |
River Styles Framework Steps in Stage 2 include: Stage 3 determines the potential for a river to 'recover', or improve in condition. Steps in Stage 3 include: Stage 4 uses information from Stages 1 to 3 to identify 'target conditions' for a River Style as a goal toward which river rehabilitation (or restoration) can work. Steps in Stage 4 include: The has been used to support river management in Australia, New Zealand, United States and Brazil. In Australia, the Department of Industry (New South Wales) used the as a key component in developing the River Condition Index (RCI) as a tool to assess river value, risk to river value and to monitor changes in river condition over time. The also contributes to the method for determining 'High Ecological Value Aquatic Ecosystems' (HEVAE) as part of the Australian National Water Initiative. In the United States, The formed part of the protocol for the Columbia Habitat Monitoring Program (CHaMP) developed for the Columbia River Basin. The CHaMP protocol used River Styles to help with comparing river types, predicting fish habitat suitability and prioritising river conservation and rehabilitation activities. A cost-benefit analysis completed by Land & Water Australia found that the had a benefit-to-cost ratio of 28:1 and had contributed a net value of $40 million (AUD) in 2010. An accreditation framework has been developed for use of the to ensure quality control. There are two levels of accreditation: 'Provisional' and 'Accredited' | https://en.wikipedia.org/wiki?curid=59969032 |
River Styles Framework 'Provisional' practitioners have undertaken a River Styles Short Course and have passed the associated assessment tasks. 'Provisional' practitioners may undertake assessments of River Styles under the supervision of a fully accredited practitioner. Full accreditation is gained following successful completion of a River Styles Short Course and completion of a satisfactory River Styles Report. 'Accredited' practitioners may undertake River Styles assessments unsupervised and may also supervise 'Provisional' practitioners. | https://en.wikipedia.org/wiki?curid=59969032 |
NGC 2300 is a lenticular galaxy in the constellation Cepheus. It was discovered in 1871 by French astronomer Alphonse Borrelly using an 18 cm telescope. | https://en.wikipedia.org/wiki?curid=59971656 |
Proton capture is a nuclear reaction in which an atomic nucleus and one or more protons collide and merge to form a heavier nucleus. Since protons have positive electric charge, they are repelled electrostatically by the positively charged nucleus. Therefore, it is more difficult for protons to enter the nucleus compared to neutrally charged neutrons . plays an important role in the cosmic nucleosynthesis of proton rich isotopes. In stars it can proceed in two ways: as a rapid (rp-process) or a slow process (p-process). | https://en.wikipedia.org/wiki?curid=59980849 |
Synthetic microbial consortia (commonly called co-cultures) are multi-population systems that can contain a diverse range of microbial species, and are adjustable to serve a variety of industrial, ecological, and tautological interests. For synthetic biology, consortia take the ability to engineer novel cell behaviors to a population level. Consortia are more common than not in nature, and generally prove to be more robust than monocultures. Just over 7,000 species of bacteria have been cultured and identified to date. Many of the estimated 1.2 million bacteria species that remain have yet to be cultured and identified, in part due to inabilities to be cultured axenically. Evidence for symbiosis between microbes strongly suggests it to have been a necessary precursor of the evolution of land plants and for their transition from algal communities in the sea to land. When designing synthetic consortia, or editing naturally occurring consortia, synthetic biologists keep track of pH, temperature, initial metabolic profiles, incubation times, growth rate, and other pertinent variables. One of the more salient applications of engineering behaviors and interactions between microbes in a community is the ability to combine or even switch metabolisms. The combination of autotrophic and heterotrophic microbes allows the unique possibility of a self-sufficient community that may produce desired biofuels to be collected | https://en.wikipedia.org/wiki?curid=59987872 |
Synthetic microbial consortia Co-culture dyads of autotrophic "Synechococcus elongatus" and heterotrophic "Escherichia coli" were found to be able to grow synchronously when the strain of "S. elongatus" was transformed to include a gene for sucrose export. The commensal combination of the sucrose-producing cyanobacteria with the modified "E. coli" metabolism may allow for a diverse array of metabolic products such as various butanol biofuels, terpenoids, and fatty-acid derived fuels. Including a heterotroph also provides a solution to the issues of contamination when producing carbohydrates, as competition may limit contaminant species viability. In isolated systems this can be a restriction to the feasibility of large-scale biofuel operations, like algae ponds, where contamination can significantly reduce the desired output. Through interactions between "Geobacter" "spp." and Methanogens from the soil in a rice paddy field, it was discovered that the use of interspecies electron transfer stimulated the production of methane. Considering the abundance of conductive metals in soils and the use of Methane (natural gas) as a fuel, this may lead to a bioenergy-producing process. Use of the extensive range of microbial metabolism offers opportunities to those interested in Bioremediation. Through consortia, synthetic biologists have been able to design an enhanced efficiency in bacteria that can excrete bio-surfactants as well as degrade hydrocarbons for the interests of cleaning oil contamination in Assam, India | https://en.wikipedia.org/wiki?curid=59987872 |
Synthetic microbial consortia Their experiment took combinations of five native naturally occurring hydrocarbon-degrading bacteria, and analyzed the different cocktails to see which degraded poly-aromatic hydrocarbons the best. The combination of "Bacillus pumilis" KS2 and "Bacillus cereus" R2 was found to be the most effective, degrading 84.15% of the TPH after 5 weeks. Further remediation efforts have turned to the issue of agricultural Pesticide run-off. Pesticides vary in class and function, and in high concentration often lead to highly toxic environmental risks. Of the over-500 types of pesticides in current use, two serious issues are their general lack of biodegradability and unpredictability. In Kyrgyzstan, researchers assessed soil around a pesticide dump and discovered not only that the soil had poor microflora diversity, but that some of the species that were present used metabolic pathways to digest the pesticides. The two most-efficient species found were "Pseudomonas fluorescens" and "Bacillus polymyxa", with "B. polymyxa" degrading 48.2% of the pesticide Aldrin after 12 days. However, when the strains were combined with each other as well as some other less-efficient yet native bacteria, pesticide degradation increased to 54.0% in the same conditions. Doolatkeldieva et al | https://en.wikipedia.org/wiki?curid=59987872 |
Synthetic microbial consortia discussed their findings, saying "It is consequently possible that the degrading capacity of the bacteria could be increased only through co-cultivation, which shows that these bacteria naturally coexist and are dependent on each other for the utilization of environmental substances. In the oxidation and hydrolysis pathways of pesticide degradation, each bacterium can produce metabolites that will be utilized by the enzyme system of the next bacterium". As an answer to the increase in use of non-biodegradable, oil-based plastics and its subsequent accumulation as waste, scientists have developed biodegradable and compostable alternatives often called Bioplastics. However, not all biologically created plastics are necessarily biodegradable, and this can be a source of confusion. Therefore it is important to distinguish between the types of bioplastics, biodegradable bioplastics which can be degraded by some microflora and simply bio-based plastics which are a renewable source of plastic but require more effort to dispose of. One of the bioplastics of interest is Polyhydroxybutyrate, abbreviated to PHB. PHB is a biodegradable bioplastic that has applications for food packaging due to being non-toxic. Repurposed "E. coli", as well as "Halomonas boliviensis", have been shown to produce PHB. PHB production starting from carbon dioxide in a co-culture between "S. elongatus" and H. boliviensis has proven to be a stable continually-productive pair for 5 months without the aid of antibiotics. | https://en.wikipedia.org/wiki?curid=59987872 |
CRISPR gene editing is a genetic engineering technique in molecular biology by which the genomes of living organisms may be modified. It is based on a simplified version of the bacterial CRISPR-Cas9 antiviral defense system. By delivering the Cas9 nuclease complexed with a synthetic guide RNA (gRNA) into a cell, the cell's genome can be cut at a desired location, allowing existing genes to be removed and/or new ones added "in vivo". Working like genetic scissors, the Cas9 nuclease opens both strands of the targeted sequence of DNA to introduce the modification by one of two methods. Knock-in mutations, facilitated via homology directed repair (HDR), is the traditional pathway of targeted genomic editing approaches. This allows for the introduction of targeted DNA damage and repair. HDR employs the use of similar DNA sequences to drive the repair of the break via the incorporation of exogenous DNA to function as the repair template. This method relies on the periodic and isolated occurrence of DNA damage at the target site in order for the repair to commence. Knock-out mutations caused by CRISPR-Cas9 result in the repair of the double-stranded break by means of non-homologous end joining (NHEJ). NHEJ can often result in random deletions or insertions at the repair site, which may disrupt or alter gene functionality. Therefore, genomic engineering by CRISPR-Cas9 gives researchers the ability to generate targeted random gene disruption. Because of this, the precision of genome editing is a great concern | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing Genomic editing leads to irreversible changes to the genome. While genome editing in eukaryotic cells has been possible using various methods since the 1980s, the methods employed had proved to be inefficient and impractical to implement on a large scale. With the discovery of CRISPR and specifically the Cas9 nuclease molecule, efficient and highly selective editing is now a reality. Cas9 derived from the bacterial species "Streptococcus pyogenes" has facilitated targeted genomic modification in eukaryotic cells by allowing for a reliable method of creating a targeted break at a specific location as designated by the crRNA and tracrRNA guide strands. The ease with which researchers can insert Cas9 and template RNA in order to silence or cause point mutations at specific loci has proved invaluable to the quick and efficient mapping of genomic models and biological processes associated with various genes in a variety of eukaryotes. Newly engineered variants of the Cas9 nuclease have been developed that significantly reduce off-target activity. CRISPR-Cas9 genome editing techniques have many potential applications, including in medicine and agriculture. The use of the CRISPR-Cas9-gRNA complex for genome editing was the AAAS's choice for Breakthrough of the Year in 2015. Many bioethical concerns have been raised about the prospect of using CRISPR for germline editing, especially in human embryos | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing In the early 2000s, researchers developed zinc finger nucleases (ZFNs), synthetic proteins whose DNA-binding domains enable them to create double-stranded breaks in DNA at specific points. In 2010, synthetic nucleases called transcription activator-like effector nucleases (TALENs) provided an easier way to target a double-stranded break to a specific location on the DNA strand. Both zinc finger nucleases and TALENs require the design and creation of a custom protein for each targeted DNA sequence, which is a much more difficult and time-consuming process than that of designing guide RNAs. CRISPRs are much easier to design because the process requires synthesizing only a short RNA sequence, a procedure that is already widely used for many other molecular biology techniques (e.g. creating oligonucleotide primers). Whereas methods such as RNA interference (RNAi) do not fully suppress gene function, CRISPR, ZFNs, and TALENs provide full irreversible gene knockout. CRISPR can also target several DNA sites simultaneously simply by introducing different gRNAs. In addition, the costs of employing CRISPR are relatively low. , SAGE Labs (part of Horizon Discovery group) had exclusive rights from one of those companies to produce and sell genetically engineered rats and non-exclusive rights for mouse and rabbit models. , Thermo Fisher Scientific had licensed intellectual property from ToolGen to develop CRISPR reagent kits. , patent rights to CRISPR were contested | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing Several companies formed to develop related drugs and research tools. As companies ramp up financing, doubts as to whether CRISPR can be quickly monetized were raised. In February 2017 the US Patent Office ruled on a patent interference case brought by University of California with respect to patents issued to the Broad Institute, and found that the Broad patents, with claims covering the application of CRISPR-Cas9 in eukaryotic cells, were distinct from the inventions claimed by University of California. Shortly after, University of California filed an appeal of this ruling. In March 2017, the European Patent Office (EPO) announced its intention to allow broad claims for editing all kinds of cells to Max-Planck Institute in Berlin, University of California, and University of Vienna, and in August 2017, the EPO announced its intention to allow CRISPR claims in a patent application that MilliporeSigma had filed. the patent situation in Europe was complex, with MilliporeSigma, ToolGen, Vilnius University, and Harvard contending for claims, along with University of California and Broad. In July 2018, the ECJ ruled that gene editing for plants was a sub-category of GMO foods and therefore that the CRISPR technique would henceforth be regulated in the European Union by their rules and regulations for GMOs. In February 2020, a US trial safely showed on 3 cancer patients. CRISPR-Cas9 genome editing is carried out with a Type II CRISPR system | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing When utilized for genome editing, this system includes Cas9, crRNA, and tracrRNA along with an optional section of DNA repair template that is utilized in either non-homologous end joining (NHEJ) or homology directed repair (HDR). CRISPR-Cas9 often employs a plasmid to transfect the target cells. The main components of this plasmid are displayed in the image and listed in the table. The crRNA is uniquely designed for each application, as this is the sequence that Cas9 uses to identify and directly bind to specific sequences within the host cell's DNA. The crRNA must bind only where editing is desired. The repair template is also uniquely designed for each application, as it must complement to some degree the DNA sequences on either side of the cut and also contain whatever sequence is desired for insertion into the host genome. Multiple crRNAs and the tracrRNA can be packaged together to form a single-guide RNA (sgRNA). This sgRNA can be included alongside the gene that codes for the Cas9 protein and made into a plasmid in order to be transfected into cells. Many online tools are available to aid in designing effective sgRNA sequences. CRISPR-Cas9 offers a high degree of fidelity and relatively simple construction. It depends on two factors for its specificity: the target sequence and the protospacer adjacent motif (PAM) sequence. The target sequence is 20 bases long as part of each CRISPR locus in the crRNA array. A typical crRNA array has multiple unique target sequences | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing Cas9 proteins select the correct location on the host's genome by utilizing the sequence to bond with base pairs on the host DNA. The sequence is not part of the Cas9 protein and as a result is customizable and can be independently synthesized. The PAM sequence on the host genome is recognized by Cas9. Cas9 cannot be easily modified to recognize a different PAM sequence. However, this is ultimately not too limiting, as it is typically a very short and nonspecific sequence that occurs frequently at many places throughout the genome (e.g. the SpCas9 PAM sequence is 5'-NGG-3' and in the human genome occurs roughly every 8 to 12 base pairs). Once these sequences have been assembled into a plasmid and transfected into cells, the Cas9 protein with the help of the crRNA finds the correct sequence in the host cell's DNA and – depending on the Cas9 variant – creates a single- or double-stranded break at the appropriate location in the DNA. Properly spaced single-stranded breaks in the host DNA can trigger homology directed repair, which is less error-prone than the non-homologous end joining that typically follows a double-stranded break. Providing a DNA repair template allows for the insertion of a specific DNA sequence at an exact location within the genome. The repair template should extend 40 to 90 base pairs beyond the Cas9-induced DNA break. The goal is for the cell's native HDR process to utilize the provided repair template and thereby incorporate the new sequence into the genome | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing Once incorporated, this new sequence is now part of the cell's genetic material and passes into its daughter cells. Delivery of Cas9, sgRNA, and associated complexes into cells can occur via viral and non-viral systems. Electroporation of DNA, RNA, or ribonucleocomplexes is a common technique, though it can result in harmful effects on the target cells. Chemical transfection techniques utilizing lipids have also been used to introduce sgRNAs in complex with Cas9 into cells. Types of cells that are more difficult to transfect (e.g. stem cells, neurons, and hematopoietic cells) require more efficient delivery systems, such as those based on lentivirus (LVs), adenovirus (AdV), and adeno-associated virus (AAV). Several variants of CRISPR-Cas9 allow gene activation or genome editing with an external trigger such as light or small molecules. These include photoactivatable CRISPR systems developed by fusing light-responsive protein partners with an activator domain and a dCas9 for gene activation, or by fusing similar light-responsive domains with two constructs of split-Cas9, or by incorporating caged unnatural amino acids into Cas9, or by modifying the guide RNAs with photocleavable complements for genome editing | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing Methods to control genome editing with small molecules include an allosteric Cas9, with no detectable background editing, that will activate binding and cleavage upon the addition of 4-hydroxytamoxifen (4-HT), 4-HT responsive intein-linked Cas9, or a Cas9 that is 4-HT responsive when fused to four ERT2 domains. Intein-inducible split-Cas9 allows dimerization of Cas9 fragments and rapamycin-inducible split-Cas9 system developed by fusing two constructs of split-Cas9 with FRB and FKBP fragments. Other studies have been able to induce transcription of Cas9 with a small molecule, doxycycline. Small molecules can also be used to improve homology directed repair, often by inhibiting the non-homologous end joining pathway. These systems allow conditional control of CRISPR activity for improved precision, efficiency, and spatiotemporal control. The clustered regularly interspaced short palindrome repeats (CRISPR)/Cas9 system is a new gene-editing technology that can induce double-strand breaks (DSBs), single-strand nicks, or anywhere guide ribonucleic acids (RNAs) can bind with the protospacer adjacent motif (PAM) sequence. By simple changing sequence of gRNA, Cas9-endonuclease can be delivered to a gene of interest and induce DSBs. The efficiency of Cas9-endonuclease and the ease by which genes can be targeted led to the development of CRISPR-knockout (KO) libraries both for mouse and human cells, which can cover either specific gene sets of interest or the whole-genome | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing CRISPR screening helps scientist to create a systematic and high-throughput genetic perturbation within live model organisms. This genetic perturbation is necessary for fully understanding gene function and epigenetic regulation. The advantage of pooled CRISPR libraries is that more genes can be targeted at once. Knock-out libraries are created in a way to achieve equal representation and performance across all expressed gRNAs and carry an antibiotic or fluorescent selection marker that can be used to recover transduced cells. There are two plasmid systems in CRISPR/Cas9 libraries. First, is all in one plasmid, where sgRNA and Cas9 are produced simultaneously in a transfected cell. Second, is a two-vector system: sgRNA and Cas9 plasmids are delivered separetly. It's important to deliver thousands of unique sgRNAs-containing vectors to a single vessel of cells by viral transduction at low multiplicity of infection (MOI, typically at 0.1-0.6), it prevents the probability that an individual cell clone will get more than one type of sgRNA otherwise it can lead to incorrect assignment of genotype to phenotype. Once pooled library is prepared it is necessary to carry out a deep sequencing (NGS, next generation sequencing) of PCR-amplifed plasmid DNA in order to reveal abundance of sgRNAs. Cells of interest can be consequentially infected by the library and then selected according to the phenotype. There are 2 types of selection: negative and positive | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing By negative selection dead or slow growing cells are efficiently detected. It can identify survival-essential genes, which can be further serve as candidates for molecularly targeted drugs. On the other hand, positive selection gives a collection of growth-advantage acquired populations by random mutagenesis. After selection genomic DNA is collected and sequenced by NGS. Depletion or enrichment of sgRNAs is detected and compared to the original sgRNA library, annotated with the target gene that sgRNA corresponds to. Statistical analysis then identify genes that are significantly likely to be relevant to the phenotype of interest. Apart from knock-out there are also knock-down (CRISPRi) and activation (CRISPRa) libraries, which using the ability of proteolytically deactivated Cas9-fusion proteins (dCas9) to bind target DNA, which means that gene of interest is not cut but is over-expressed or repressed. It made CRISPR/Cas9 system even more interesting in gene editing. Inactive dCas9 protein modulate gene expression by targeting dCas9-repressors or activators toward promoter or transcriptional start sites of target genes. For repressing genes Cas9 can be fused to KRAB effector domain that makes complex with gRNA, whereas CRISPRa utilizes dCas9 fused to different transcriptional activation domains, which are further directed by gRNA to promoter regions to upregulate expression. Cas9 genomic modification has allowed for the quick and efficient generation of transgenic models within the field of genetics | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing Cas9 can be easily introduced into the target cells along with sgRNA via plasmid transfection in order to model the spread of diseases and the cell's response to and defense against infection. The ability of Cas9 to be introduced "in vivo" allows for the creation of more accurate models of gene function and mutation effects, all while avoiding the off-target mutations typically observed with older methods of genetic engineering. The CRISPR and Cas9 revolution in genomic modeling does not extend only to mammals. Traditional genomic models such as "Drosophila melanogaster", one of the first model organisms, have seen further refinement in their resolution with the use of Cas9. Cas9 uses cell-specific promoters allowing a controlled use of the Cas9. Cas9 is an accurate method of treating diseases due to the targeting of the Cas9 enzyme only affecting certain cell types. The cells undergoing the Cas9 therapy can also be removed and reintroduced to provide amplified effects of the therapy. CRISPR-Cas9 can be used to edit the DNA of organisms "in vivo" and to eliminate individual genes or even entire chromosomes from an organism at any point in its development. Chromosomes that have been successfully deleted "in vivo" using CRISPR techniques include the Y chromosome and X chromosome of adult lab mice and human chromosomes 14 and 21, in embryonic stem cell lines and aneuploid mice respectively | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing This method might be useful for treating genetic disorders caused by abnormal numbers of chromosomes, such as Down syndrome and intersex disorders. Successful "in vivo" genome editing using CRISPR-Cas9 has been shown in numerous model organisms, including "Escherichia coli", "Saccharomyces cerevisiae", "Candida albicans", "Caenorhadbitis elegans", "Arabidopsis" spp., "Danio rerio", and "Mus musculus". Successes have been achieved in the study of basic biology, in the creation of disease models, and in the experimental treatment of disease models. Concerns have been raised that off-target effects (editing of genes besides the ones intended) may confound the results of a experiment (i.e. the observed phenotypic change may not be due to modifying the target gene, but some other gene). Modifications to CRISPR have been made to minimize the possibility of off-target effects. Orthogonal CRISPR experiments are often recommended to confirm the results of a gene editing experiment. CRISPR simplifies the creation of genetically modified organisms for research which mimic disease or show what happens when a gene is knocked down or mutated. CRISPR may be used at the germline level to create organisms in which the targeted gene is changed everywhere (i.e. in all cells/tissues/organs of a multicellular organism), or it may be used in non-germline cells to create local changes that only affect certain cell populations within the organism. CRISPR can be utilized to create human cellular models of disease | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing For instance, when applied to human pluripotent stem cells, CRISPR has been used to introduce targeted mutations in genes relevant to polycystic kidney disease (PKD) and focal segmental glomerulosclerosis (FSGS). These CRISPR-modified pluripotent stem cells were subsequently grown into human kidney organoids that exhibited disease-specific phenotypes. Kidney organoids from stem cells with PKD mutations formed large, translucent cyst structures from kidney tubules. The cysts were capable of reaching macroscopic dimensions, up to one centimeter in diameter. Kidney organoids with mutations in a gene linked to FSGS developed junctional defects between podocytes, the filtering cells affected in that disease. This was traced to the inability of podocytes to form microvilli between adjacent cells. Importantly, these disease phenotypes were absent in control organoids of identical genetic background, but lacking the CRISPR modifications. A similar approach was taken to model long QT syndrome in cardiomyocytes derived from pluripotent stem cells. These CRISPR-generated cellular models, with isogenic controls, provide a new way to study human disease and test drugs. CRISPR-Cas technology has been proposed as a treatment for multiple human diseases, especially those with a genetic cause. Its ability to modify specific DNA sequences makes it a tool with potential to fix disease-causing mutations | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing Early research in animal models suggest that therapies based on CRISPR technology have potential to treat a wide range of diseases, including cancer, beta-thalassemia, sickle cell disease, hemophilia, cystic fibrosis, Duchenne's muscular dystrophy, Huntington's disease, and heart disease. CRISPR may also have applications in tissue engineering and regenerative medicine, such as by creating human blood vessels that lack expression of MHC class II proteins, which often cause transplant rejection. CRISPR-Cas-based "RNA-guided nucleases" can be used to target virulence factors, genes encoding antibiotic resistance, and other medically relevant sequences of interest. This technology thus represents a novel form of antimicrobial therapy and a strategy by which to manipulate bacterial populations. Recent studies suggest a correlation between the interfering of the CRISPR-Cas locus and acquisition of antibiotic resistance. This system provides protection of bacteria against invading foreign DNA, such as transposons, bacteriophages, and plasmids. This system was shown to be a strong selective pressure for the acquisition of antibiotic resistance and virulence factor in bacterial pathogens. Therapies based on CRISPR–Cas3 gene editing technology delivered by engineered bacteriophages could be used to destroy targeted DNA in pathogens. Cas3 is more destructive than the better known Cas9. Research suggests that CRISPR is an effective way to limit replication of multiple herpesviruses | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing It was able to eradicate viral DNA in the case of Epstein-Barr virus (EBV). Anti-herpesvirus CRISPRs have promising applications such as removing cancer-causing EBV from tumor cells, helping rid donated organs for immunocompromised patients of viral invaders, or preventing cold sore outbreaks and recurrent eye infections by blocking HSV-1 reactivation. , these were awaiting testing. CRISPR may revive the concept of transplanting animal organs into people. Retroviruses present in animal genomes could harm transplant recipients. In 2015, a team eliminated 62 copies of a particular retroviral DNA sequence from the pig genome in a kidney epithelial cell. Researchers recently demonstrated the ability to birth live pig specimens after removing these retroviruses from their genome using CRISPR for the first time. CRISPR had been studied in animal models and cancer cell lines, to learn if it can be used to repair or thwart mutated genes that cause cancer. The first clinical trial involving CRISPR started in 2016. It involved removing immune cells from people with lung cancer, using CRISPR to edit out the gene expressed PD-1, then administrating the altered cells back to the same person. 20 other trials were under way or nearly ready, mostly in China, . In 2016, the United States Food and Drug Administration (FDA) approved a clinical trial in which CRISPR would be used to alter T cells extracted from people with different kinds of cancer and then administer those engineered T cells back to the same people | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing Using "dead" versions of Cas9 (dCas9) eliminates CRISPR's DNA-cutting ability, while preserving its ability to target desirable sequences. Multiple groups added various regulatory factors to dCas9s, enabling them to turn almost any gene on or off or adjust its level of activity. Like RNAi, CRISPR interference (CRISPRi) turns off genes in a reversible fashion by targeting, but not cutting a site. The targeted site is methylated, epigenetically modifying the gene. This modification inhibits transcription. These precisely placed modifications may then be used to regulate the effects on gene expressions and DNA dynamics after the inhibition of certain genome sequences within DNA. Within the past few years, epigenetic marks in different human cells have been closely researched and certain patterns within the marks have been found to correlate with everything ranging from tumor growth to brain activity. Conversely, CRISPR-mediated activation (CRISPRa) promotes gene transcription. Cas9 is an effective way of targeting and silencing specific genes at the DNA level. In bacteria, the presence of Cas9 alone is enough to block transcription. For mammalian applications, a section of protein is added. Its guide RNA targets regulatory DNA sequences called promoters that immediately precede the target gene. Cas9 was used to carry synthetic transcription factors that activated specific human genes | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing The technique achieved a strong effect by targeting multiple CRISPR constructs to slightly different locations on the gene's promoter. In 2016, researchers demonstrated that CRISPR from an ordinary mouth bacterium could be used to edit RNA. The researchers searched databases containing hundreds of millions of genetic sequences for those that resembled CRISPR genes. They considered the fusobacteria "Leptotrichia shahii". It had a group of genes that resembled CRISPR genes, but with important differences. When the researchers equipped other bacteria with these genes, which they called C2c2, they found that the organisms gained a novel defense. Many viruses encode their genetic information in RNA rather than DNA that they repurpose to make new viruses. HIV and poliovirus are such viruses. Bacteria with C2c2 make molecules that can dismember RNA, destroying the virus. Tailoring these genes opened any RNA molecule to editing. CRISPR-Cas systems can also be employed for editing of micro-RNA and long-noncoding RNA genes in plants. Gene drives may provide a powerful tool to restore balance of ecosystems by eliminating invasive species. Concerns regarding efficacy, unintended consequences in the target species as well as non-target species have been raised particularly in the potential for accidental release from laboratories into the wild. Scientists have proposed several safeguards for ensuring the containment of experimental gene drives including molecular, reproductive, and ecological | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing Many recommend that immunization and reversal drives be developed in tandem with gene drives in order to overwrite their effects if necessary. There remains consensus that long-term effects must be studied more thoroughly particularly in the potential for ecological disruption that cannot be corrected with reversal drives. As such, DNA computing would be required. Unenriched sequencing libraries often have abundant undesired sequences. Cas9 can specifically deplete the undesired sequences with double strand breakage with up to 99% efficiency and without significant off-target effects as seen with restriction enzymes. Treatment with Cas9 can deplete abundant rRNA while increasing pathogen sensitivity in RNA-seq libraries. Prime editing (or base editing) is a CRISPR refinement to accurately insert or delete sections of DNA. The CRISPR edits are not always perfect and the cuts can end up in the wrong place. Both issues are a problem for using the technology in medicine. Prime editing does not cut the double-stranded DNA but instead uses the CRISPR targeting apparatus to shuttle an additional enzyme to a desired sequence, where it converts a single nucleotide into another. The new guide, called a pegRNA, contains an RNA template for a new DNA sequence to be added to the genome at the target location. That requires a second protein, attached to Cas9: a reverse transcriptase enzyme, which can make a new DNA strand from the RNA template and insert it at the nicked site | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing Those three independent pairing events each provide an opportunity to prevent off-target sequences, which significantly increases targeting flexibility and editing precision. Prime editing was developed by researchers at the Broad Institute of MIT and Harvard in Massachusetts. More work is needed to optimize the methods. As of March 2015, multiple groups had announced ongoing research with the intention of laying the foundations for applying CRISPR to human embryos for human germline engineering, including labs in the US, China, and the UK, as well as US biotechnology company OvaScience. Scientists, including a CRISPR co-discoverer, urged a worldwide moratorium on applying CRISPR to the human germline, especially for clinical use. They said "scientists should avoid even attempting, in lax jurisdictions, germline genome modification for clinical application in humans" until the full implications "are discussed among scientific and governmental organizations". These scientists support further low-level research on CRISPR and do not see CRISPR as developed enough for any clinical use in making heritable changes to humans. In April 2015, Chinese scientists reported results of an attempt to alter the DNA of non-viable human embryos using CRISPR to correct a mutation that causes beta thalassemia, a lethal heritable disorder. The study had previously been rejected by both "Nature" and "Science" in part because of ethical concerns | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing The experiments resulted in successfully changing only some of the intended genes, and had off-target effects on other genes. The researchers stated that CRISPR is not ready for clinical application in reproductive medicine. In April 2016, Chinese scientists were reported to have made a second unsuccessful attempt to alter the DNA of non-viable human embryos using CRISPR – this time to alter the CCR5 gene to make the embryo resistant to HIV infection. In December 2015, an International Summit on Human Gene Editing took place in Washington under the guidance of David Baltimore. Members of national scientific academies of the US, UK, and China discussed the ethics of germline modification. They agreed to support basic and clinical research under certain legal and ethical guidelines. A specific distinction was made between somatic cells, where the effects of edits are limited to a single individual, and germline cells, where genome changes can be inherited by descendants. Heritable modifications could have unintended and far-reaching consequences for human evolution, genetically (e.g. gene-environment interactions) and culturally (e.g. social Darwinism). Altering of gametocytes and embryos to generate heritable changes in humans was defined to be irresponsible. The group agreed to initiate an international forum to address such concerns and harmonize regulations across countries | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing In November 2018, Jiankui He announced that he had edited two human embryos to attempt to disable the gene for CCR5, which codes for a receptor that HIV uses to enter cells. He said that twin girls, Lulu and Nana, had been born a few weeks earlier. He said that the girls still carried functional copies of CCR5 along with disabled CCR5 (mosaicism) and were still vulnerable to HIV. The work was widely condemned as unethical, dangerous, and premature. An international group of scientists called for a global moratorium on genetically editing human embryos. Policy regulations for the CRISPR-Cas9 system vary around the globe. In February 2016, British scientists were given permission by regulators to genetically modify human embryos by using CRISPR-Cas9 and related techniques. However, researchers were forbidden from implanting the embryos and the embryos were to be destroyed after seven days. The US has an elaborate, interdepartmental regulatory system to evaluate new genetically modified foods and crops. For example, the Agriculture Risk Protection Act of 2000 gives the United States Department of Agriculture the authority to oversee the detection, control, eradication, suppression, prevention, or retardation of the spread of plant pests or noxious weeds to protect the agriculture, environment, and economy of the US. The act regulates any genetically modified organism that utilizes the genome of a predefined "plant pest" or any plant not previously categorized | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing In 2015, Yinong Yang successfully deactivated 16 specific genes in the white button mushroom to make them non-browning. Since he had not added any foreign-species (transgenic) DNA to his organism, the mushroom could not be regulated by the USDA under Section 340.2. Yang's white button mushroom was the first organism genetically modified with the CRISPR-Cas9 protein system to pass US regulation. In 2016, the USDA sponsored a committee to consider future regulatory policy for upcoming genetic modification techniques. With the help of the US National Academies of Sciences, Engineering, and Medicine, special interests groups met on April 15 to contemplate the possible advancements in genetic engineering within the next five years and any new regulations that might be needed as a result. In 2017, the Food and Drug Administration proposed a rule that would classify genetic engineering modifications to animals as "animal drugs", subjecting them to strict regulation if offered for sale and reducing the ability for individuals and small businesses to make them profitable. In China, where social conditions sharply contrast with those of the West, genetic diseases carry a heavy stigma. This leaves China with fewer policy barriers to the use of this technology. In 2012 and 2013, CRISPR was a runner-up in "Science Magazine"'s Breakthrough of the Year award. In 2015, it was the winner of that award. CRISPR was named as one of "MIT Technology Review"s 10 breakthrough technologies in 2014 and 2016 | https://en.wikipedia.org/wiki?curid=59990826 |
CRISPR gene editing In 2016, Jennifer Doudna and Emmanuelle Charpentier, along with Rudolph Barrangou, Philippe Horvath, and Feng Zhang won the Gairdner International award. In 2017, Doudna and Charpentier were awarded the Japan Prize in Tokyo, Japan for their revolutionary invention of CRISPR-Cas9. In 2016, Charpentier, Doudna, and Zhang won the Tang Prize in Biopharmaceutical Science. | https://en.wikipedia.org/wiki?curid=59990826 |
František Vejdovský (born 24 October 1849 in Kouřim - died 4 December 1939 in Prague) was a Czech zoologist. In 2007 the International Commission on Zoological Nomenclature ruled that the family "Tubificidae" was a junior synonym of Naididae. | https://en.wikipedia.org/wiki?curid=59991676 |
Electric bacteria are forms of bacteria that directly consume and excrete electrons at different energy potentials without requiring the metabolization of any sugars or other nutrients. "Shewanella" and "Geobacter" are two known types of electric bacteria. This form of life appears to be especially adapted to low-oxygen environments. Most life forms require an oxygen environment in which to release the excess of electrons which are produced in metabolizing sugars. In a low oxygen environment, this pathway for releasing electrons is not available. Instead, electric bacteria "breath" metals instead of oxygen, which effectively results in both an intake of and excretion of electrical charges. | https://en.wikipedia.org/wiki?curid=60010424 |
Maria Florianivna Makarevych (1907–1982) was a Ukrainian botanist and lichenologist noted for studying lichens of the Carpathian region, and for publishing multiple influential monographs. The genus "Marfloraea" is named in her honor. | https://en.wikipedia.org/wiki?curid=60019197 |
Arsenic minerals The arsenic minerals or arsenic group are a group of trigonal symmetry minerals composed of arsenic-like elements, and one alloy. The elements are arsenic, antimony and bismuth. The alloy is stibarsen (SbA) an alloy of arsenic and antimony. | https://en.wikipedia.org/wiki?curid=60020038 |
Acetomicrobium hydrogeniformans is an anaerobic and moderately thermophilic bacterium from the genus of "Acetomicrobium" which has been isolated from oil production water from North Slope Borough in the United States. | https://en.wikipedia.org/wiki?curid=60026694 |
Aminiphilus is a Gram-negative, non-spore-forming and motile genus of bacteria from the family of Synergistaceae with one known species ("circumscriptus"). "circumscriptus" has been isolated from anaerobic sludge from Colombia. | https://en.wikipedia.org/wiki?curid=60033993 |
Thermovirga is a Gram-negative, anaerobic and motile genus of bacteria from the family of Synergistaceae with one known species ("lienii"). "lienii" has been isolated from production water from an oil well from the North Sea in Norway. | https://en.wikipedia.org/wiki?curid=60034051 |
Thermanaerovibrio is a Gram-negative, non-spore-forming chemoorganotrophic and thermophilic genus of bacteria from the family of Synergistaceae. | https://en.wikipedia.org/wiki?curid=60034099 |
Thermanaerovibrio velox is a Gram-negative, moderately thermophilic, organotrophic and anaerobic bacterium from the genus of "Thermanaerovibrio" which has been isolated from cyanobacterial mat from Uzon caldera in Russia. | https://en.wikipedia.org/wiki?curid=60034173 |
Thermanaerovibrio acidaminovorans is a moderately thermophilic and anaerobic bacterium from the genus of "Thermanaerovibrio" which has been isolated from granular methanogenic sludge from Breda in the Netherlands. | https://en.wikipedia.org/wiki?curid=60034222 |
Hachimoji DNA (from Japanese "hachimoji", "eight letters") is a synthetic nucleic acid analog that uses four synthetic nucleotides in addition to the four present in the natural nucleic acids, DNA and RNA. This leads to four allowed base pairs: two unnatural base pairs formed by the synthetic nucleobases in addition to the two normal pairs. Hachimoji bases have been demonstrated in both DNA and RNA analogs, using deoxyribose and ribose respectively as the backbone sugar. Benefits of such a nucleic acid system may include an enhanced ability to store data, as well as insights into what may be possible in the search for extraterrestrial life. The hachimoji DNA system produced one type of catalytic RNA (ribozyme or aptamer) "in vitro". Natural DNA is a molecule carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life. DNA is a polynucleotide as it is composed of simpler monomeric units called nucleotides; when double-stranded, the two chains coil around each other to form a double helix. In natural DNA, each nucleotide is composed of one of four nucleobases (cytosine [C], guanine [G], adenine [A] or thymine [T]), a sugar called deoxyribose, and a phosphate group | https://en.wikipedia.org/wiki?curid=60040145 |
Hachimoji DNA The nucleotides are joined to one another in a chain by covalent bonds between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone. The nitrogenous bases of the two separate polynucleotide strands are bound to each other with hydrogen bonds, according to base pairing rules (A with T and C with G), to make double-stranded DNA. is similar to natural DNA but differs in the number, and type, of nucleobases. Unnatural nucleobases, more hydrophobic than natural bases, are used in successful hachimoji DNA. Such a DNA always formed the standard double helix, no matter what sequence of bases were used. An enzyme (T7 polymerase) was adapted by the researchers to be used "in vitro" to transcribe hachimoji DNA into hachimoji RNA, which, in turn, produced chemical activity in the form of a glowing green fluorophore. DNA and RNA are naturally composed of four nucleotide bases that form hydrogen bonds in order to pair. uses an additional four synthetic nucleotides to form four types of base pairs, two of which are unnatural: P binds with Z and B binds with S (dS in DNA, rS in RNA). Earlier, the research group responsible for the hachimoji DNA system, headed by Harvard University chemist Steven Benner, had studied a synthetic DNA analog system, named Artificially Expanded Genetic Information System (AEGIS), that used twelve different nucleotides, including the four found in DNA | https://en.wikipedia.org/wiki?curid=60040145 |
Hachimoji DNA Scripps Research chemist Floyd Romesberg, noted for creating the first Unnatural Base Pair (UBP), and expanding the genetic alphabet of four letters to six in 2012, stated that the invention of the hachimoji DNA system is an example of the fact that the natural bases (G, C, A and T) "are not unique". Creating new life forms may be possible, at least theoretically, with the new DNA system. For now, however, the hachimoji DNA system is not self-sustaining; the system needs a steady supply of unique building blocks and proteins found only in the laboratory. As a result, "can go nowhere if it escapes the laboratory." NASA funded this research to "expand[s] the scope of the structures that we might encounter as we search for life in the cosmos". According to Lori Glaze of the Planetary Science Division of NASA, "Life detection is an increasingly important goal of NASA's planetary science missions, and this new work [with hachimoji DNA] will help us to develop effective instruments and experiments that will expand the scope of what we look for." Research team leader Steven Benner notes, "By carefully analyzing the roles of shape, size and structure in hachimoji DNA, this work expands our understanding of the types of molecules that might store information in extraterrestrial life on alien worlds | https://en.wikipedia.org/wiki?curid=60040145 |
Hachimoji DNA " According to researchers, hachimoji DNA could also be used "to develop clean diagnostics for human diseases, in DNA digital data storage, DNA barcoding, self-assembling nanostructures, and to make proteins with unusual amino acids. Parts of this hachimoji DNA are already being commercially produced by Firebird Biomolecular Sciences LLC". | https://en.wikipedia.org/wiki?curid=60040145 |
Neodymium fluoride Neodymium(III) fluoride is an inorganic chemical compound of neodymium and fluorine with the formula NdF. It is a purplish pink colored solid with a high melting point. Like other lanthanide fluorides it is highly insoluble in water which allows it to be synthesised from aqueous neodymium nitrate via a reaction with hydrofluoric acid, from which it precipitates as a hydrate: Anhydrous material may be obtain by the simple drying of the hydrate, in contrast to the hydrates of other neodymium halides, which form mixed oxyhalides if heated. | https://en.wikipedia.org/wiki?curid=60041207 |
Cloacibacillus is a Gram-negative and anaerobic genus of bacteria from the family of Synergistaceae. "Cloacibacillus" bacteria are pathogenic. | https://en.wikipedia.org/wiki?curid=60042632 |
Cloacibacillus evryensis is a Gram-negative, anaerobic, mesophilic, rod-shaped and non-motile bacterium from the genus of "Cloacibacillus" which has been isolated from sewage sludge from a wastewater treatment plant from Evry in France. | https://en.wikipedia.org/wiki?curid=60042670 |
Cloacibacillus porcorum is a Gram-negative, anaerobic, mesophilic and non-motile bacterium from the genus of "Cloacibacillus" which has been isolated from the intestinal tract of a pig from Ames in the United States. | https://en.wikipedia.org/wiki?curid=60042727 |
Aminobacterium is a Gram-negative genus of bacteria from the family of Synergistaceae. | https://en.wikipedia.org/wiki?curid=60042760 |
Aminobacterium mobile is a Gram-negative, anaerobic, mesophilic, non-spore-forming and motile bacterium from the genus of "Aminobacterium" which has been isolated from anaerobic lagoon from a dairy wastewater treatment plant in Colombia. Dissimilar to "Aminobacterium colombiense", has a marginally lower DNA GC-content (44 mol% vs 46 mol%.) "Aminobacterium mobile" is motile and ferments Serine to Acetate and Alanine. "Aminobacterium mobile" is both a Heterotroph and Asaccharolytic. Its adverse effects on both animals and humans are not yet known, but because of the ability of "Aminobacterium mobile" to degrade amino acids and peptides, the possibility of harmful effects cannot be excluded. | https://en.wikipedia.org/wiki?curid=60042848 |
Aminobacterium colombiense is a Gram-negative, mesophilic, strictly anaerobic and non-spore-forming bacterium from the genus of "Aminobacterium" which has been isolated from anaerobic lagoon from a dairy wastewater treatment plant in Colombia. | https://en.wikipedia.org/wiki?curid=60042873 |
Aminobacterium thunnarium is a Gram-negative, anaerobic, mesophilic and non-spore-forming bacterium from the genus of "Aminobacterium" which has been isolated from sludge. | https://en.wikipedia.org/wiki?curid=60042926 |
Ada Prins (18 September 1879, Amsterdam – 20 July 1977, Voorburg) became in 1908 the first woman in the Netherlands to hold a doctorate in chemistry. Having obtained her doctorate at the University of Amsterdam with the thesis "Vloeiende mengkristallen in binaire stelsels", she developed her reputation by writing chemistry text books. She had a romantic relationship with the poet, Herman Gorter from 1901. | https://en.wikipedia.org/wiki?curid=60044056 |
Shinobu Akiyama (秋山 忍 b. 1957) is a Japanese botanist who works at the Tsukuba Botanical Garden studying the taxonomy of spermatophytes, particularly in the Tibetan plateau and Himalayan mountains , she is the author or one of the authors of 170 taxon names in the International Plant Names Index. | https://en.wikipedia.org/wiki?curid=60044419 |
Acetomicrobium flavidum is a thermophilic bacterium in the genus Acetomicrobium. It was first isolated from thermophilic, anaerobic sewage sludge digester operated at . The bacterium is gram negative and highly motile. The species represented around 25% of the microbial population in the sludge. | https://en.wikipedia.org/wiki?curid=60046320 |
ROSE test The resistivity of solvent extract (ROSE) test is a test for the presence and average concentration of soluble ionic contaminants, for example on a printed circuit board (PCB). It was developed in the early 1970s. Some manufacturers use it as part of Six Sigma processes. Some modern fluxes have low solubility in traditional ROSE solvents such as water and isopropyl alcohol, and therefore require the use of different solvents. | https://en.wikipedia.org/wiki?curid=60054667 |
Pyramidobacter is a Gram-negative genus of bacteria from the family of Synergistaceae with one known species ("piscolens"). "piscolens" has been isolated from the human mouth. | https://en.wikipedia.org/wiki?curid=60058413 |
Lactivibrio is a genus of bacteria from the family of Synergistaceae with one known species ("alcoholicus"). "alcoholicus" has been isolated from mesophilic granular sludge from Tokyo in Japan. | https://en.wikipedia.org/wiki?curid=60058463 |
Jonquetella is a Gram-negative and strictly aerobic genus of bacteria from the family of Synergistaceae with one known species ("Lactivibrio alcoholicus"). "anthropi" has been isolated from a human cyst from Montpellier in France. | https://en.wikipedia.org/wiki?curid=60058498 |
Fretibacterium is a genus of bacteria from the family of Synergistaceae with one known species ("fastidiosum"). "fastidiosum" has been isolated from subgingival plaque. | https://en.wikipedia.org/wiki?curid=60058616 |
Aminivibrio is a Gram-negative genus of bacteria from the family of Synergistaceae with one known species ("pyruvatiphilus"). "pyruvatiphilus" has been isolated from soil from a rice field. | https://en.wikipedia.org/wiki?curid=60058659 |
Bruce McNaughton Peter Bruce L. McNaughton is a Canadian neuroscientist and Distinguished Professor at the University of California, Irvine (UC Irvine), as well as a Professor of Neuroscience and director of the Polaris Brain Dynamics research group at The Canadian Centre for Behavioural Neuroscience. He joined the faculty of UC Irvine in 2014, after having taught at the University of Lethbridge for six years. He had moved his lab from the University of Arizona to the University of Lethbridge in 2008 after winning the Polaris Award from the Alberta Heritage Foundation for Medical Research. He was elected as a Fellow of the Royal Society of Canada in 2016. He is also a lifetime member of the Royal Norwegian Society of Sciences and Letters. | https://en.wikipedia.org/wiki?curid=60060547 |
Nautilia is a genus of bacteria from the family of Synergistaceae. | https://en.wikipedia.org/wiki?curid=60068367 |
Petrogenetic grid A petrogenetic grid is a geological phase diagram that connects the stability ranges or metastability ranges of metamorphic minerals or mineral assemblages to the conditions of metamorphism. Experimentally determined mineral or mineral-assemblage stability ranges are plotted as metamorphic reaction boundaries in a pressure–temperature cartesian coordinate system to produce a petrogenetic grid for a particular rock composition. The regions of overlap of the stability fields of minerals form equilibrium mineral assemblages used to determine the pressure–temperature conditions of metamorphism. This is particularly useful in geothermobarometry. For example, suppose one came across a metapelitic rock containing chlorite, kaolinite, and quartz. As illustrated by the given petrogenetic grid on metapelites, one sees that such a rock can only form at relatively low pressures and temperatures. However, if it had carpolite instead of chlorite, then it would have formed at higher pressures, and if it had pyrophyllite instead of kaolinite, it would have formed at higher temperatures. Note, this assumes the rock has a KFMASH composition, since that is what the experimental data was created with. If the composition of the rock differs from this, then the figure is less accurate. Norman L. Bowen proposed the idea in 1940 | https://en.wikipedia.org/wiki?curid=60073783 |
Petrogenetic grid At the time, he envisioned geologists eventually determining every possible metemorphic reaction and assembalge in nature, but realized that the magnitude of undertaking the necessary experiments was a huge task that would not be finished for a very long time. As such, modern petrogenetic grids are only partially complete. Depending on the level of precision and characterization needed, a petrogenetic grid may be simple, or it may be an extremely large system consisting of a hundred or more reactions. To the right is an example of a rather complex petrogenetic grid for metamorphosed pelitic rocks. It shows most of the important reactions that govern the development of aluminous mineral assemblages from the prehnite-pumpellyite facies to the granulite facies, as well as the blueschist facies and eclogite facies at higher pressures and the contact hornfels facies at lower pressures. As the rock undergoes higher temperatures and pressures, one can see it follow the classic Barrovian sequence from the chlorite zone to the biotite zone to the garnet zone to the staurolite zone. | https://en.wikipedia.org/wiki?curid=60073783 |
Nitratifractor is a genus of bacteria from the family of unclassified Campylobacterales with one known species ("salsuginis"). | https://en.wikipedia.org/wiki?curid=60076031 |
NGC 1310 is a spiral galaxy located in the Fornax constellation. It was discovered by English astronomer John Herschel on 22 October 1835. | https://en.wikipedia.org/wiki?curid=60078036 |
NGC 1337 is a spiral galaxy in the Eridanus constellation. It was discovered by British astronomer Lewis Swift on 10 November 1885. | https://en.wikipedia.org/wiki?curid=60079602 |
Idiomarinaceae is a Gram-negative and mesophilic family in the order of Alteromonadales. Bacteria of the family occur in saline environments. | https://en.wikipedia.org/wiki?curid=60090029 |
Geology of Africa The geology of Africa is varied and complex, and gives rise to the wide variety of landscapes found across the continent. | https://en.wikipedia.org/wiki?curid=60104192 |
Rosalina Berazaín Iturralde (born 21 February 1947, Havana) is a Cuban botanist, plant collector, plant taxonomist, and professor at the University of Havana. She is one of the founders of the National Botanic Garden of Cuba, and a member of the Cuban Academy of Sciences. The species "Coccoloba berazainae" and "Coccoloba berazainiae" were named in her honor. | https://en.wikipedia.org/wiki?curid=60106332 |
Ferrimonadaceae is a family in the order of Alteromonadales. | https://en.wikipedia.org/wiki?curid=60117175 |
NGC 1161 is a lenticular galaxy approximately 90 million light-years away from Earth in the constellation of Perseus. It was discovered, along with NGC 1160, by English astronomer John Herschel on October 7, 1784. is classified as a Type 1.9 Seyfert galaxy. It forms a visual pair with the galaxy NGC 1160. Both galaxies are located between the Local and Perseus superclusters in the Perseus Cloud close to the centre of the Local Void. | https://en.wikipedia.org/wiki?curid=60120651 |
NGC 1160 is a spiral galaxy approximately 116 million light-years away from Earth in the constellation of Perseus. It was discovered, along with NGC 1161, by English astronomer John Herschel on October 7, 1784. forms a visual pair with the galaxy NGC 1161. Both galaxies are located between the Local and Perseus superclusters. | https://en.wikipedia.org/wiki?curid=60125052 |
Neepa Maitra Neepa T. Maitra is a theoretical physicist and Professor of Physics at Hunter College of the City University of New York and the Graduate Center of the City University of New York. She is most well known for her contributions to theoretical chemistry and chemical physics, especially in the development of accurate functionals in time-dependent density functional theory and correlated electron-ion dynamics. Maitra was born and raised in New Zealand and completed her bachelor's degree in physics at the University of Otago. She went on to get her Ph.D. in physics at Harvard University in the lab of Eric "Rick" Heller and postdoc at the University of California, Berkeley and Rutgers University. Maitra received an NSF Career Award for her work in Theoretical and Computational Chemistry. | https://en.wikipedia.org/wiki?curid=60128647 |
Yehuda Farissol (; ) was a Jewish-Italian mathematician and astronomer. In 1499 he published a description of the astronomical sphere with diagrams, under the title "Iggeret S'fira" ("Epistle of the Sphere"). | https://en.wikipedia.org/wiki?curid=60129827 |
Alma Theodora Lee (born 12 April 1912, Tingha, died 20 October 1990, Wellington) was an Australian botanist and plant taxonomist who worked at the National Herbarium of New South Wales, University of Sydney, and CSIRO. She is notable for raising the standard of systematic botany in Australia, and for her revisions of "Swainsona" and "Typha". She also studied the "Fabaceae" with colleagues. She described over 40 species. The March 1991 issue of the journal "Telopea" was dedicated to her memory. | https://en.wikipedia.org/wiki?curid=60144651 |
Subcrop (geology) Subcrop is a term in geology. It is a contrast to the term "outcrop", if not a perfect antonym. If rocks exposed at the present-day erosion surface are referred to as outcrops, then now-buried rocks that were exposed at ancient erosion surfaces are referred to as "subcrops". So, a subcrop is buried. If part of a geological formation is close to the surface, it is a "subcrop". A subcrop is not outcropping, and is usually under the soil profile or alluvial sediments. | https://en.wikipedia.org/wiki?curid=60160726 |
Ali Wallace (naturalist) Ali Wallace ("fl." 1840-1907) was the name used by a Malay who accompanied and assisted Alfred Russel Wallace in his travels and explorations from 1855 to 1862. Initially recruited as a cook for his expedition, Ali was later responsible for independently collecting many significant specimens that are credited to Wallace. He also made observations of the birds and the people which were communicated to Wallace. It has been estimated that Ali collected and prepared nearly 5,150 bird specimens. Many of his specimens survive in collections of natural history museums. Alfred Russel Wallace travelled to the Malay archipelago in March 1854 along with his collecting assistant Charles Martin Allen (1839–92). During his travels he hired as many as 1200 people at various points of time and in various places. Among them some made an impression on him and were credited in his writings. When they arrived in Singapore on 18 April 1854, Wallace hired a Malay boy named Ali. He described him: Ali later became an expert at shooting and skinning birds. He accompanied Wallace and Allen and became one his most trusted servants. On Aru, it was probably Ali who collected the specimens of the king bird-of-paradise ("Cicinnurus regius"). He also collected an ivory-breasted pitta (described as "Pitta gigas") from Halmahera. Ali accompanied Wallace to New Guinea in 1858 before returning to Ternate. It was on Batchian on 24 August 1858 that Ali went to collect birds while Wallace collected insects | https://en.wikipedia.org/wiki?curid=60161743 |
Ali Wallace (naturalist) Wallace wrote: The species was named by George Robert Gray as "Semioptera wallacii" or Wallace's standardwing. While at Ternate, Ali married a woman and he did not join Wallace in 1859. Ali joined Wallace again in 1861 on a trip to the island of Bouru. In 1862 Wallace went to Singapore where he began preparations to return home to England. Here he provided Ali with money, guns, ammunition and various supplies. Wallace had him photographed and in his 1905 book notes: In 1907 American herpetologist Thomas Barbour was in Ternate and he noted in his 1943 memoir: A 2015 analysis by John van Wyhe and Gerrell M. Drawhorn noted that Ali was more than just a working assistant but that he truly immersed himself into the study of birds. "Searching for Ali Wallace", a documentary film, was produced in 2016. | https://en.wikipedia.org/wiki?curid=60161743 |
Ortho effect refers mainly to the set of steric effects and some bonding interactions along with polar effects caused by the various substituents which are in a given molecule altering its chemical properties and physical properties. In a general sense the ortho effect is associated with substituted benzene compounds. There are three main ortho effects in substituted benzene compounds: When any group is present at ortho to carboxyl group in substituted benzoic acid then the acidic character of that compound becomes at least more than benzoic acid. Generally ortho-substituted benzoic acids are stronger acids than their meta and para isomers also. The table given below shows pKa values of various monosubstituted benzoic acids. When a group is present ortho to carboxylic acid group in substituted benzoic acid, the steric hindrance forces the carboxyl group to twist out of the plane of the benzene ring. This inhibits the resonance of carboxyl group with phenyl ring which increases the acidity of carboxyl group which was otherwise reduced due to destabilizing cross conjugation. In-fact this destabilizing cross conjugation is also accounted as the reason for decreased acidity of benzoic acid as compared to formic acid. Also the presence of a hydrogen bond donor near a carboxyl group may act to enhance its acidity, as demonstrated by the three isomeric hydroxy-benzoic acids (refer the table above) | https://en.wikipedia.org/wiki?curid=60166827 |
Ortho effect Intramolecular hydrogen bonding of an ortho OH donor to the carbonyl oxygen of the carboxyl group, acting as an acceptor, increases the positive charge on the carbonyl carbon and consequently the acidity of the carboxyl OH. When any group is present at ortho to NH in aniline then the basic character of that compound becomes at least less than aniline. For example see the order of basicity of following substituted aniline:- When a meta-directing group is meta to an ortho–para-directing group, the incoming group primarily goes ortho to the meta-directing group rather than para. This is called the ortho effect.There is no good explanation yet for the ortho effect, though possibly there is intramolecular assistance from the meta-directing group. For example the electrophilic aromatic nitration of 1-methyl-3-nitrobenzene affords 4-methyl-1,2-dinitrobenzene and 1-methyl-2,3-dinitrobenzene in 60.1% and 28.4% yields, respectively. In contrast, 2-methyl-1,4-dinitrobenzene (2c) is isolated in only 9.9% yield. As witnessed in the above example, when a π-acceptor substituent (πAS) is meta to a π-donor substituent (πDS), the electrophilic aromatic nitration occurs ortho to the πAS rather than para. Similar results were also observed on the nitration of 3-methylbenzoic acid in which 5-methyl-2-nitrobenzoic acid and 3-methyl-2-nitrobenzoic acid were obtained as the major compounds, whereas 3-methyl-4-nitrobenzoic acid was reported as a minor compound | https://en.wikipedia.org/wiki?curid=60166827 |
Ortho effect Also in nitration of the nitration of 3-bromobenzoic acid 5-bromo-2-nitrobenzoic acid (83%yield) was obtained as major product and 3-bromo-2-nitrobenzoic acid (13% yield) as minor. On an interesting note the potential isomer 3-bromo-4-nitrobenzoic acid was not detected. In normal electron demand Diels-Alder reactions, the Z-substituted dienophiles react with 1-substituted butadienes to give 3,4-disubstituted cyclohexenes, independent of the nature of diene substituents. This is also known as ortho effect. | https://en.wikipedia.org/wiki?curid=60166827 |
G. C. Anupama G C Anupama is Dean and Senior Professor, Indian Institute of Astrophysics (IIA) in Bengaluru. She is currently (for the period of 2019-2022) serving as president of the Astronomical Society of India (ASI), becoming the first woman to head this association of professional astronomers in India. Anupama is a member of the Indian core team which is part of the international effort to establish the thirty meter telescope (TMT) in Hawaii, USA. Anupama was also in charge for the design and establishment of the Himalayan Telescope at Hanle near Leh in Ladakh, the world's ninth highest site for optical, infrared and gamma-ray telescopes in the world. Anupama has published articles in the field of astronomy, with a focus on the initial physical conditions after a Supernova. She has also been the editor of the Journal of the ASI. She is also studying ‘transients’ — objects that brighten up for a brief period of time before going dark in space. Anupama has received the Sir CV Raman Young Scientist Award in 2001 and is a fellow of National Academy of Sciences India and the Indian Academy of Sciences.She completed her PhD in 1991 from IIA and has been a faculty member at the institute since 1995. | https://en.wikipedia.org/wiki?curid=60170373 |
Rutheniridosmine is a naturally occurring mineral alloy of the elements ruthenium, iridium and osmium with the formula of (Ir,Os,Ru). occurs as hexagonal, opaque, silver-white, metallic grains with a Mohs hardness of six. Platinum, palladium, rhodium, iron, and nickel occur as impurities. occurs in association with sperrylite, hollingworthite, iridarsenite, ruthenarsenite, michenerite, laurite, geversite, moncheite, and chromite. Type localities include: the Ruby Creek, Spruce Creek, and Bullion mines of British Columbia, Canada and the Horokanai placer deposit, of Kamikawa Subprefecture, Hokkaidō, Japan. | https://en.wikipedia.org/wiki?curid=60172494 |
Achalaite ((Fe, Mn)(Ti, Fe, Ta)(Nb, Ta)O) is a black mineral of the wodginite group, first discovered in 2013. It crystallizes in the monoclinic system and has a dark, metallic luster, a specific gravity of 6.285 and a Mohs hardness of 5.5. occurs in the intermediate zone of topaz- and tantalite-bearing pegmatite. Associated minerals include rutile, quartz and albite. Its name comes from the type locality: the Achala batholith in Córdoba, Argentina and the mineral has been approved by the IMA with the acronym "2013-103". | https://en.wikipedia.org/wiki?curid=60174967 |
NGC 3239 is an irregular galaxy in the constellation of Leo. It is the host of SN 2012A, the first supernova of 2012. The galaxy, which was discovered in 1784 by William Herschel, is part of the New Galactic Catalogue, and with an apparent magnitude of 13.5, is not visible to the naked eye. It has been shown to have many HII regions, while also having some star formation regions. These signs are common in galactic mergers, which is why it is believed that is the result of a galactic merger. The supernova, SN 2012A, has been classified as a type IIP supernova, with a shorter plateau and non-constant luminosity. | https://en.wikipedia.org/wiki?curid=60178638 |
Cyclohexanehexathione is a cyclic covalent compound consisting of a six-carbon ring with a sulfur bonded to each. It has been synthesized by neutralization of its monoanion (CS) in a mass spectrometer. This compound is the thioketone analog of cyclohexanehexone; that oxygen variant is expected to be substantially less stable. Synthesis of CS by photolysis or pyrolysis to extrude three equivalents of carbon monoxide from a precursor containing adjacent pairs of sulfurs as cyclic dithiocarbonate units gave what is more likely a different valence isomer, as various dithiete-containing structures are predicted to be more stable than the hexathione form. This theoretical analysis of the various isomers and experimental analysis of this reaction cast doubt on whether the mass spectrometric approach really did produce the hexathione isomer as originally claimed. The increased stability of dithietes as compared to dioxetane-like rings is one of theoretical bases for proposing CS is more stable than the oxygen analog. | https://en.wikipedia.org/wiki?curid=60181385 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.