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A siphon barometer is the term sometimes applied to the simplest of mercury barometers. A continuous U-shaped tube of the same diameter throughout is sealed on one end and filled with mercury. When placed into the upright, "U", position, mercury will flow away from the sealed end, forming a partial vacuum, until balanced by atmospheric pressure on the other end. The term "siphon" derives from the belief that air pressure is involved in the operation of a siphon. The difference in height of the fluid between the two arms of the U-shaped tube is the same as the maximum intermediate height of a siphon. When used to measure pressures other than atmospheric pressure, a siphon barometer is sometimes called a siphon gauge; these are not siphons but follow a standard U-shaped design leading to the term. Siphon barometers are still produced as precision instruments. Siphon barometers should not be confused with a siphon rain gauge., | 1 | Applied and Interdisciplinary Chemistry |
Photothermal effect is a phenomenon associated with electromagnetic radiation. It is produced by the photoexcitation of material, resulting in the production of thermal energy (heat).
It is sometimes used during treatment of blood vessel lesions, laser resurfacing, laser hair removal and laser surgery. | 0 | Theoretical and Fundamental Chemistry |
He was born at Vizille and trained at the Ecole des Arts et Métiers at Aix. From 1874 until about 1880, he worked as a chemist at the new factory of the Cotton Powder Company at Uplees, Faversham, Kent, England. While there, he and the factory manager, George Trench, took out patents for Tonite (a new high explosive) (1874), and an improved dynamite detonator (1878).
In 1880, Faure patented a method of coating lead plates with a paste of lead oxides, sulphuric acid and water, which was then cured by gentle warming in a humid atmosphere. The curing process caused the paste to change to a mixture of lead sulphates which adhered to the lead plate. During charging the cured paste was converted into electrochemically active material (the "active mass") and gave a substantial increase in capacity compared with Planté's battery. This was a significant breakthrough that led to the industrial manufacture of lead-acid batteries, as now used for starting motor cars.
Towards the end of his life Faure was granted further patents, among them ones for the manufacture of aluminium alloys and improvements to hot air engines and motor vehicle steering mechanisms. | 0 | Theoretical and Fundamental Chemistry |
Polyamorphism may apply to all amorphous states, i.e. glasses, other amorphous solids, supercooled liquids, ordinary liquids or fluids. A liquid–liquid transition however, is one that occurs only in the liquid state (red line in the phase diagram, top right). In this article liquid–liquid transitions are defined as transitions between two liquids of the same chemical substance. Elsewhere the term liquid–liquid transition may also refer to the more common transitions between liquid mixtures of different chemical composition.
The stable liquid state unlike most glasses and amorphous solids, is a thermodynamically stable equilibrium state. Thus new liquid–liquid or fluid-fluid transitions in the stable liquid (or fluid) states are more easily analysed than transitions in amorphous solids where arguments are complicated by the non-equilibrium, non-ergodic nature of the amorphous state. | 0 | Theoretical and Fundamental Chemistry |
The connectivity of streams to their adjacent floodplain along their entire length plays an important role in the equilibrium of the river system. Streams are shaped by the water and sediment fluxes from their watershed, and any alteration of these fluxes (either in quantity, intensity or timing) will result in changes in equilibrium planform and cross-sectional geometry, as well as modifications of the aquatic and riparian ecosystem. Removal or modification of levees can allow a better connection between streams and their floodplain. Similarly, removing dams and grade control structures can restore water and sediment fluxes and result in more diversified habitats, although impacts on fish communities can be difficult to assess.
In streams where existing infrastructures cannot be removed or modified, it is also possible to optimize sediment and water management in order to maximize connectivity and achieve flow patterns that ensure minimum ecosystem requirements. This can include releases from dams, but also delaying and/or treating water from agricultural and urban sources. | 1 | Applied and Interdisciplinary Chemistry |
Hydrostatic CCC or centrifugal partition chromatography (CPC) was invented in the 1980s by the Japanese company Sanki Engineering Ltd, whose president was Kanichi Nunogaki. CPC has been extensively developed in France starting from the late 1990s. In France, they initially optimized the stacked disc concept initiated by Sanki. More recently, in France and UK, non-stacked disc CPC configurations have been developed with PTFE, stainless steel or titanium rotors. These have been designed to overcome possible leakages between the stacked discs of the original concept, and to allow steam cleaning for good manufacturing practice. The volumes ranging from a 100 ml to 12 liters are available in different rotor materials. The 25-liter rotor CPC has a titanium rotor. This technique is sometimes sold under the name "fast" CPC or "high-performance" CPC. | 0 | Theoretical and Fundamental Chemistry |
* FECOM Object Learning Software (OLS), industrial in-line hyperspectral feature processing
*[http://evince.umbio.com/ UmBio Evince Image, multivariate hyperspectral image analysis ]
* Perception System; in-line hyperspectral imaging for industry | 0 | Theoretical and Fundamental Chemistry |
The Nusselt number may be obtained by a non-dimensional analysis of Fourier's law since it is equal to the dimensionless temperature gradient at the surface:
:, where q is the heat transfer rate, k is the constant thermal conductivity and T the fluid temperature.
Indeed, if: and
we arrive at
then we define
so the equation becomes
By integrating over the surface of the body:
where . | 1 | Applied and Interdisciplinary Chemistry |
During World War I, Curie recognised that wounded soldiers were best served if operated upon as soon as possible. She saw a need for field radiological centres near the front lines to assist battlefield surgeons, including to obviate amputations when in fact limbs could be saved. After a quick study of radiology, anatomy, and automotive mechanics, she procured X-ray equipment, vehicles, and auxiliary generators, and she developed mobile radiography units, which came to be popularly known as petites Curies ("Little Curies"). She became the director of the Red Cross Radiology Service and set up France's first military radiology centre, operational by late 1914. Assisted at first by a military doctor and her 17-year-old daughter Irène, Curie directed the installation of 20 mobile radiological vehicles and another 200 radiological units at field hospitals in the first year of the war. Later, she began training other women as aides.
In 1915, Curie produced hollow needles containing "radium emanation", a colourless, radioactive gas given off by radium, later identified as radon, to be used for sterilizing infected tissue. She provided the radium from her own one-gram supply. It is estimated that over a million wounded soldiers were treated with her X-ray units. Busy with this work, she carried out very little scientific research during that period. In spite of all her humanitarian contributions to the French war effort, Curie never received any formal recognition of it from the French government.
Also, promptly after the war started, she attempted to donate her gold Nobel Prize medals to the war effort but the French National Bank refused to accept them. She did buy war bonds, using her Nobel Prize money. She said:
She was also an active member in committees of Polonia in France dedicated to the Polish cause. After the war, she summarized her wartime experiences in a book, Radiology in War (1919). | 0 | Theoretical and Fundamental Chemistry |
*Agricola, Georgius, 1556, Translation Hoover, Herbert, 1912, De re metallica, [http://farlang.com/books/agricola-hoover-de-re-metallica Farlang, full streaming version + scientific introduction]
*Craddock, P. T., 1989. Metalworking Techniques. In: Youngs, S. (ed), Work of Angels: Masterpieces of Celtic Metalwork, 6th-9th centuries AD, 170–213.
*Forbes, R. J., 1957. Metallurgy. In: Singer, C., Holmyard, E. J., Hall, A. R. & Williams, T. I. (eds), A History of Technology, vol. 2: The Mediterranean Civilizations and the Middle Ages c. 700 BC to AD 1500. Oxford: Clarendon Press, 41–80.
*Martinon-Torres, M. & Rehren, Th., in press (a). Metallurgy, Europe. In: Encyclopedia of Society and Culture in the Medieval World. Dallas: Schlager.
*Martinon-Torres, M. & Rehren, Th., in press (b). Mining, Europe. In: Encyclopedia of Society and Culture in the Medieval World. Dallas: Schlager.
*Smith, C.S. & Hawthorne, J.H., 1974. Mappae Clavicula, A little key to the world of medieval techniques. Transactions of American Philosophical Society 64 (4), 1–128.
*Theophilus, On Divers Arts: The foremost medieval treatise on Painting, Glassmaking and Metalwork. Hawthorne, J.G. & Smith, C.S. (trans), 1979. New York: Dover Publications. | 1 | Applied and Interdisciplinary Chemistry |
Coelenterazine is widely found in marine organisms including:
*radiolarians
*ctenophores
*cnidarians such as Aequorea victoria, Obelia geniculata and Renilla reniformis
*squid such as Watasenia scintillans and Vampyroteuthis infernalis
*shrimp such as Systellaspis debilis and Oplophorus gracilirostris
*copepods such as Pleuromamma xiphias and Gaussia princeps
*chaetognaths
*fish including some Neoscopelidae and Myctophidae
*echinoderms such as Amphiura filiformis
The compound has also been isolated from organisms that are not luminescent, such as the Atlantic herring and several shrimp species including Pandalus borealis and Pandalus platyuros. | 1 | Applied and Interdisciplinary Chemistry |
A 5 cap (also termed an RNA cap, an RNA 7-methylguanosine cap, or an RNA mG cap) is a modified guanine nucleotide that has been added to the "front" or 5 end of a eukaryotic messenger RNA shortly after the start of transcription. The 5 cap consists of a terminal 7-methylguanosine residue that is linked through a 5-5'-triphosphate bond to the first transcribed nucleotide. Its presence is critical for recognition by the ribosome and protection from RNases.
Cap addition is coupled to transcription, and occurs co-transcriptionally, such that each influences the other. Shortly after the start of transcription, the 5' end of the mRNA being synthesized is bound by a cap-synthesizing complex associated with RNA polymerase. This enzymatic complex catalyzes the chemical reactions that are required for mRNA capping. Synthesis proceeds as a multi-step biochemical reaction. | 1 | Applied and Interdisciplinary Chemistry |
Many LGBT communities centre their support around cisgender gay, lesbian and bisexual people and neglect to include proper support for transgender people. The same 2020 literature review analyses the social, emotional and physical experiences of pregnant transgender men. A common obstacle faced by pregnant transgender men is the possibility of gender dysphoria. Literature shows that transgender men report uncomfortable procedures and interactions during their pregnancies as well as feeling misgendered due to gendered terminology used by healthcare providers. Outside of the healthcare system, pregnant transgender men may experience gender dysphoria due to cultural assumptions that all pregnant people are cisgender women. These people use three common approaches to navigating their pregnancy: passing as a cisgender woman, hiding their pregnancy, or being out and visibly pregnant as a transgender man. Some transgender and gender diverse patients describe their experience in seeking gynaecological and reproductive health care as isolating and discriminatory, as the strictly binary healthcare system often leads to denial of healthcare coverage or unnecessary revelation of their transgender status to their employer.
Many transgender people retain their original sex organs and choose to have children through biological reproduction. Advances in assisted reproductive technology and fertility preservation have broadened the options transgender people have to conceive a child using their own gametes or a donor's. Transgender men and women may opt for fertility preservation before any gender affirming surgery, but it is not required for future biological reproduction. It is also recommended that fertility preservation is conducted before any hormone therapy. Additionally, while fertility specialists often suggest that transgender men discontinue their testosterone hormones prior to pregnancy, research on this topic is still inconclusive. However, a 2019 study found that transgender male patients seeking oocyte retrieval via assisted reproductive technology (including IVF) were able to undergo treatment four months after stopping testosterone treatment, on average. All patients experienced menses and normal AMH, FSH and E levels and antral follicle counts after coming off testosterone, which allowed for successful oocyte retrieval. Despite assumptions that the long-term androgen treatment negatively impacts fertility, oocyte retrieval, an integral part of the IVF process, does not appear to be affected.
Biological reproductive options available to transgender women include, but are not limited to, IVF and IUI with the trans womans sperm and a donor or a partners eggs and uterus. Fertility treatment options for transgender men include, but are not limited to, IUI or IVF using his own eggs with a donors sperm and/or donors eggs, his uterus, or a different uterus, whether that is a partners or a surrogates. | 1 | Applied and Interdisciplinary Chemistry |
The PDE5 enzyme has a molecular mass of 200 kDa and its active state is a homodimer. PDE5 consists of monomers and each contains two major functional domains: the regulatory domain (R domain) which is located in the N-terminal portion of the protein and the catalytic domain (C domain) located in the more C-terminal portion of the protein.
The R domain contains specific allosteric cGMP binding site that controls the enzymes function. This specific binding site consists of subdomain GAF (cGMP-specific cGMP-stimulated PDE, adenylate cyclase, and FhlA) which is located in the N-terminal section of the specific proteins. The allosteric binding site GAF consists of GAFa and GAFb where GAFa has a higher binding affinity. The importance and functional role of the two homologous binding sites are unknown.
Conformational change occurs when cGMP binds to the allosteric site that exposes serine and permits phosphorylation. The results for the phosphorylation of serine leads to increased cGMP hydrolysis at the catalytic domain. The affinity of the catalytic domain for cGMP increases and further increases the PDE5 catalytic domain activity.
Through the C domain, intracellular cGMP is degraded rapidly by PDE5 which minimizes the activity of cGMP on its PKG1 substrate by cleaving the cyclic phosphate part of cGMP to GMP. GMP is an inactive molecule with no second messenger activity.
Phosphorylation of a single serine by PKG1 and the allosteric cGMP binding site activates the PDE5 catalytic activity and the result is a negative feedback regulation of cGMP/NO/PKG1 signalling. cGMP therefore interacts with both allosteric and catalytic domain of the PDE5 enzyme and PDE5 inhibitors compete with cGMP for binding at the catalytic domain resulting in higher cGMP levels. PDE5 domains are demonstrated in . | 1 | Applied and Interdisciplinary Chemistry |
If a dopant is added to the material (example: Nd in BaTiO) the impurity will tend to stick to the grain boundaries. As the grain boundary tries to move (as atoms jump from the convex to concave surface) the change in concentration of the dopant at the grain boundary will impose a drag on the boundary. The original concentration of solute around the grain boundary will be asymmetrical in most cases. As the grain boundary tries to move, the concentration on the side opposite of motion will have a higher concentration and therefore have a higher chemical potential. This increased chemical potential will act as a backforce to the original chemical potential gradient that is the reason for grain boundary movement. This decrease in net chemical potential will decrease the grain boundary velocity and therefore grain growth. | 1 | Applied and Interdisciplinary Chemistry |
Many artificial radionuclides of technological importance are produced as fission products within nuclear reactors. A fission product is a nucleus with approximately half the mass of a uranium or plutonium nucleus which is left over after such a nucleus has been "split" in a nuclear fission reaction.
Caesium-137 is one such radionuclide. It has a half-life of 30 years, and decays by beta decay without gamma ray emission to a metastable state of barium-137 (). Barium-137m has a half-life of a 2.6 minutes and is responsible for all of the gamma ray emission in this decay sequence. The ground state of barium-137 is stable.
The photon energy (energy of a single gamma ray) of is about 662 keV. These gamma rays can be used, for example, in radiotherapy such as for the treatment of cancer, in food irradiation, or in industrial gauges or sensors. is not widely used for industrial radiography as other nuclides, such as cobalt-60 or iridium-192, offer higher radiation output for a given volume.
Iodine-131 is another important gamma-emitting radionuclide produced as a fission product. With a short half-life of 8 days, this radioisotope is not of practical use in radioactive sources in industrial radiography or sensing. However, since iodine is a component of biological molecules such as thyroid hormones, iodine-131 is of great importance in nuclear medicine, and in medical and biological research as a radioactive tracer.
Lanthanum-140 is a decay product of barium-140, a common fission product. It is a potent gamma emitter. It was used in high quantities during the Manhattan Project for the RaLa Experiments. | 0 | Theoretical and Fundamental Chemistry |
*Karl Fischer titration: A potentiometric method to analyze trace amounts of water in a substance. A sample is dissolved in methanol, and titrated with Karl Fischer reagent (consists of iodine, sulfur dioxide, a base and a solvent, such as alcohol). The reagent contains iodine, which reacts proportionally with water. Thus, the water content can be determined by monitoring the electric potential of excess iodine. | 0 | Theoretical and Fundamental Chemistry |
RIfS is used especially as a detection method in chemo- and biosensors.
Chemosensors are particularly suitable for measurements under difficult conditions and in the gaseous phase. As sensitive layers, mostly non-selective measuring polymers are used which sort the analytes according to size (the so-called molecular sieve effect when using microporous polymers) or according to polarity (e.g. functionalized polydimethylsiloxanes). When performing non-selective measurements, a sum signal from several analytes is measured which means that multivariate data analyses such as neural networks have to be used for quantification. However, it is also possible to use selectively measuring polymers, so-called molecular imprinted polymers (MIPs) which provide artificial recognition elements.
When using biosensors, polymers such as polyethylene glycols or dextrans are applied onto the layer system, and on these recognition elements for biomolecules are immobilized. Basically, any molecule can be used as recognition element (proteins such as antibodies, DNA/RNA such as aptamers, small organic molecules such as estrone, but also lipids such as phospholipid membranes).
RIfS, like SPR is a label-free technique, which allows the time-resolved observation of interaction among the binding partners without the use of fluorescence or radioactive labels. | 0 | Theoretical and Fundamental Chemistry |
Lactonase (EC 3.1.1.81, acyl-homoserine lactonase; systematic name N-acyl--homoserine-lactone lactonohydrolase) is a metalloenzyme, produced by certain species of bacteria, which targets and inactivates acylated homoserine lactones (AHLs). It catalyzes the reaction
: an N-acyl--homoserine lactone + HO an N-acyl--homoserine
Many species of α-, β-, and γ-proteobacteria produce acylated homoserine lactones, small hormone-like molecules commonly used as communication signals between bacterial cells in a population to regulate certain gene expression and phenotypic behaviours. This type of gene regulation is known as quorum sensing.
Other names for these types of enzymes are Quorum-quenching N-acyl-homoserine lactonase, acyl homoserine degrading enzyme, acyl-homoserine lactone acylase, AHL lactonase, AHL-degrading enzyme, AHL-inactivating enzyme, AHLase, AhlD, AhlK, AiiA, AiiA lactonase, AiiA-like protein, AiiB, AiiC, AttM, delactonase, lactonase-like enzyme, N-acyl homoserine lactonase, N-acyl homoserine lactone hydrolase, N-acyl-homoserine lactone lactonase, N-acyl--homoserine lactone hydrolase, quorum-quenching lactonase, quorum-quenching N-acyl homoserine lactone hydrolase. | 1 | Applied and Interdisciplinary Chemistry |
PCBs or biphenyl cannot provide energy for microbes, so they are primary energy and carbon sources. As stated before it takes months sometimes for microorganisms to activate their gene for dichlorine after the first exposure to PCBs. It has been proposed to use analogs to promote the activation of genes. However, even after the metabolic pathway is activated, the intermediates of the pathway create a bottleneck effect due to their toxicity. Also, there is the possibility that BP pathway leads to protoanemonin which is a dead-end metabolite that cannot be utilized by cells. Due to the high energy cost of this pathway, if no preferred energy source present in the system, cells will not activate this pathway. | 1 | Applied and Interdisciplinary Chemistry |
Post-transcriptional regulation is the control of gene expression at the RNA level. It occurs once the RNA polymerase has been attached to the gene's promoter and is synthesizing the nucleotide sequence. Therefore, as the name indicates, it occurs between the transcription phase and the translation phase of gene expression. These controls are critical for the regulation of many genes across human tissues. It also plays a big role in cell physiology, being implicated in pathologies such as cancer and neurodegenerative diseases. | 1 | Applied and Interdisciplinary Chemistry |
Reverse electron flow (also known as reverse electron transport) is a mechanism in microbial metabolism. Chemolithotrophs using an electron donor with a higher redox potential than NAD(P)/NAD(P)H, such as nitrite or sulfur compounds, must use energy to reduce NAD(P). This energy is supplied by consuming proton motive force to drive electrons in a reverse direction through an electron transport chain and is thus the reverse process as forward electron transport. In some cases, the energy consumed in reverse electron transport is five times greater than energy gained from the forward process. Autotrophs can use this process to supply reducing power for inorganic carbon fixation.
Reverse electron transfer (RET) is the process that can occur in respiring mitochondria, when a small fraction of electrons from reduced ubiquinol is driven upstream by the membrane potential towards mitochondrial complex I. This results in reduction of oxidized pyridine nucleotide (NAD or NADP). This is a reversal of the exergonic reaction of forward electron transfer in the mitochondrial complex I when electrons travel from NADH to ubiquinone. | 1 | Applied and Interdisciplinary Chemistry |
Another typical example is that of the particles in a nucleus of an atom. The radius of the nucleus is roughly:
where A is the number of nucleons.
The number density of nucleons in a nucleus is therefore:
This density must be divided by two, because the Fermi energy only applies to fermions of the same type. The presence of neutrons does not affect the Fermi energy of the protons in the nucleus, and vice versa.
The Fermi energy of a nucleus is approximately:
where m is the proton mass.
The radius of the nucleus admits deviations around the value mentioned above, so a typical value for the Fermi energy is usually given as 38 MeV. | 0 | Theoretical and Fundamental Chemistry |
Ampicillin is well-absorbed from the GI tract (though food reduces its absorption), and reaches peak concentrations in one to two hours. The bioavailability is around 62% for parenteral routes. Unlike other penicillins, which usually bind 60–90% to plasma proteins, ampicillin binds to only 15–20%.
Ampicillin is distributed through most tissues, though it is concentrated in the liver and kidneys. It can also be found in the cerebrospinal fluid when the meninges become inflamed (such as, for example, meningitis). Some ampicillin is metabolized by hydrolyzing the beta-lactam ring to penicilloic acid, though most of it is excreted unchanged. In the kidneys, it is filtered out mostly by tubular secretion; some also undergoes glomerular filtration, and the rest is excreted in the feces and bile.
Hetacillin and pivampicillin are ampicillin esters that have been developed to increase bioavailability. | 0 | Theoretical and Fundamental Chemistry |
The terms megaphyll, macrophyll, mesophyll, notophyll, microphyll, nanophyll and leptophyll are used to describe leaf sizes (in descending order), in a classification devised in 1934 by Christen C. Raunkiær and since modified by others. | 0 | Theoretical and Fundamental Chemistry |
Paranitroaniline can be used instead of sugar, if the experiment is allowed to proceed under an obligatory fumehood. With this method the reaction phase prior to the black snake's appearance is longer, but once complete, the black snake itself rises from the container very rapidly. This reaction may cause an explosion if too much sulfuric acid is used. | 1 | Applied and Interdisciplinary Chemistry |
The nitride ligand can be both electrophilic and nucleophilic. Terminal nitrides of early metals tend to be basic and oxidizable, whereas nitrides of the later metals tend to be oxidizing and electrophilic. The former behavior is illustrated by their N-protonation and N-alkylation. Ru and Os nitrido complexes often add organophosphines to give iminophosphine derivatives containing the RPN ligand. | 0 | Theoretical and Fundamental Chemistry |
Though transposable elements were discovered due in large part to their deleterious effects, epigenetic research has shown that they may be, in some cases, beneficial to the host organism.(1,5) This research indicates that the distinction between those two aspects, mutualist and parasite, may be harder to accurately describe than was once thought. | 1 | Applied and Interdisciplinary Chemistry |
Second-generation or "Next-Gen" (NGS) techniques have evolved radically: the sequencing capacity has increased more than ten thousandfold and the cost has dropped by over one million-fold since 2007(National Human Genome Research Institute). NGS has revolutionized the genetic field in many ways. | 1 | Applied and Interdisciplinary Chemistry |
In January 2017, the US Food and Drug Administration approved an over-the-counter preparation. Levocetirizine had previously received authorization by the FDA as a prescription drug in 2007, having already been brought to market throughout much of Europe. In India, a prescription-only drug containing levocetirizine hydrochloride and montelukast is sold as Crohist MK. | 0 | Theoretical and Fundamental Chemistry |
The rotary vacuum drum filter designs available vary in physical aspects and their characteristics. The filtration area ranges from 0.5 m to 125 m. Disregarding the size of the design, filter cloth washing is a priority as it ensures efficiency of cake washing and acting vacuum. However, a smaller design would be more economical as the maintenance, energy usage and investment cost would be less than a bigger rotary vacuum drum filter.
Over the years, the technology drive has pushed development to further heights revolving around rotary vacuum drum filter in terms of design, performance, maintenance and cost. This has also led to the development of smaller rotary drum vacuum filters, ranging from laboratory scale to pilot scale, both of which can be used for smaller applications (such as at a lab in a university) High performance capacity, optimised filtrate drainage with low flow resistance and minimal pressure loss are just a few of the benefits.
With advanced control systems prompting automation, this has reduced the operation of attention needed hence, reducing the operational cost. Advancements in technology also means that precoat can be cut to 1/20th the thickness of human hair, thus making the use of precoat more efficient Lowered operational and capital cost can also be achieved nowadays due to easier maintenance and cleaning. Complete cell emptying can be done quickly with the installation of leading and trailing pipes.
Given that the filter cloth is usually one of the more expensive component in the rotary vacuum drum filter build up, priority on its maintenance must be kept quite high. A longer lifetime, protection from damage and consistent performance are the few criteria that must not be overlooked.
Besides considering production cost and quality, cake washing and cake thickness are essential issues that are important in the process. Methods have been performed to ensure a minimal amount of cake moisture while undergoing good cake washing with large cake dewatering angle. An even thickness of filter cake besides having a complete cake discharge is also possible. | 0 | Theoretical and Fundamental Chemistry |
α-Neoendorphin is an endogenous opioid peptide with a decapeptide structure and the amino acid sequence Tyr-Gly-Gly-Phe-Leu-Arg-Lys-Tyr-Pro-Lys.
α-Neoendorphin is a neuropeptide. Prodynorphin or Proenkephalin B is its precursor. Researchers and anatomists have not yet studied the distribution of α-neoendorphin in the human in detail. However, some studies have been done which supports the presence of α-neoendorphin immunoreactive fibers throughout the human brainstem. According to a study done by Duque, Ewing, Arturo Mangas, Pablo Salinas, Zaida Díaz-cabiale, José Narváez, and Rafael Coveñas; α-neoendorphin immunoreactive fibers can be found in the caudal part of the solitary nucleus, in the caudal and the gelatinosa parts of the spinal trigeminal nucleus, and only low density was found in the central grey matter of medulla. | 1 | Applied and Interdisciplinary Chemistry |
Micelles refers to a type of supramolecular structure consisting of amphiphilic molecules self-assemblies, usually hollow centered. Researchers successfully conjugated a diblock copolymer site specifically onto GFP, the resulting amphiphilic polymer-protein conjugate is capable of reversible self-assembly into micelles.
In addition to retaining the native globular shape of proteins, the polypeptide backbone of denatured proteins can also be utilized to be conjugated with hydrophilic polymer chains to generate higher ordered structure through hydrophobic interactions. For example, nanoconjugates of poly-ethylene glycol(PEG) and denatured bovine serum albumin(BSA) will spontaneously self-assemble into a micellar structure, whose protein core can adsorb high numbers of hydrophobic drugs. | 1 | Applied and Interdisciplinary Chemistry |
Due to their extensive use, non-ferrous scrap metals are usually recycled. The secondary materials in scrap are vital to the metallurgy industry, as the production of new metals often needs them. Some recycling facilities re-smelt and recast non-ferrous materials; the dross is collected and stored onsite while the metal fumes are filtered and collected. Non-ferrous scrap metals are sourced from industrial scrap materials, particle emissions and obsolete technology (for example, copper cables) scrap. | 1 | Applied and Interdisciplinary Chemistry |
For methanol the following parameters can be obtained:
The reference temperature has been T = 174.61 K and the reference pressure P has been set to 0 kPa.
Methanol is a component where the Simon–Glatzel works well in the given validity range. | 0 | Theoretical and Fundamental Chemistry |
Antarctic fungi species such as Metschnikowia sp., Cryptococcus gilvescens, Cryptococcus victoriae, Pichia caribbica and Leucosporidium creatinivorum can withstand extreme cold and still provide efficient biodegradation of contaminants. Due to the nature of colder, remote environments like Antarctica, usual methods of contaminant remediation, such as the physical removal of contaminated media, can prove costly. Most species of psychrophilic Antarctic fungi are resistant to the decreased levels of ATP (adenosine triphosphate) production causing reduced energy availability, decreased levels of oxygen due to the low permeability of frozen soil, and nutrient transportation disruption caused by freeze-thaw cycles. These species of fungi are able to assimilate and degrade compounds such as phenols, n-Hexadecane, toluene, and polycyclic aromatic hydrocarbons in these harsh conditions. These compounds are found in crude oil and refined petroleum.
Some fungi species, like Rhodotorula taiwanensis, are resistant to the extremely low pH (acidic) and radioactive medium found in radioactive waste and can successfully grow in these conditions, unlike most other organisms. They can also thrive in the presence of high concentrations of mercury and chromium. Fungi such as Rhodotorula taiwanensis can possibly be used in the bioremediation of radioactive waste due to their low pH and radiation resistant properties. Certain species of fungi are able to absorb and retain radionuclides such as Cs, Sr, Eu, Pu and Am. In fact, cell walls of some species of dead fungi can be used as a filter that can adsorb heavy metals and radionuclides present in industrial effluents, preventing them from being released into the environment. | 1 | Applied and Interdisciplinary Chemistry |
CAF commonly occurs between adjacent vias (i.e. plated through holes) inside a PCB, as the copper migrates along the glass/resin interface from anode to cathode. CAF failures can manifest as current leakage, intermittent electrical shorts, and even dielectric breakdown between conductors in printed circuit boards. This often makes CAF very difficult to detect, especially when it occurs as an intermittent issue. There are a few things that can be done to isolate the fault location and confirm CAF as a root cause of a failure. If the issue is intermittent then putting the sample of interest under combined temperature-humidity-bias (THB) may help recreate the failure mode. In addition, techniques such as cross sectioning or superconducting quantum interference device (SQUID) can be used to identify the failure. | 0 | Theoretical and Fundamental Chemistry |
Recent trends in high-density interconnects have led to the use of copper pillar solder bumps (CPB) for CPU and GPU packaging. CPBs are an attractive replacement for traditional solder bumps because they provide a fixed stand-off independent of pitch. This is extremely important as most of the high-end products are underfilled and a smaller standoff may create difficulties in getting the underfill adhesive to flow under the die.
Figure 2 shows an example of a CPB fabricated by Intel and incorporated into their Presler line of microprocessors among others. The cross section shows copper and a copper pillar (approximately 60 um high) electrically connected through an opening (or via) in the chip passivation layer at the top of the picture. At the bottom is another copper trace on the package substrate with solder between the two copper layers. | 0 | Theoretical and Fundamental Chemistry |
Wilma K. Olson (born ) is the Mary I. Bunting professor at the Rutgers Center for Quantitative Biology (CQB) (formerly known as BioMaPS institute for Quantitative Biology) at Rutgers University. Olson has her own research group on the New Brunswick campus. Although she is a polymer chemist by training, her research aims to understand the influence of chemical architecture on the conformation, properties, and interactions of nucleic acids. | 1 | Applied and Interdisciplinary Chemistry |
Fowler's research has led to new fundamental knowledge, development of important scientific tools, and has broad impacts in the application of nuclear medicine to diagnostics and health. She has worked for much of her career developing radiotracers for brain imaging to understand the mechanisms underlying drug addiction. Most recently, she has been engaged in developing methods to understand the relationship between genes, brain chemistry, and behavior.
In 1976, Fowler and her colleagues designed and synthesized a radioactively "tagged" form of sugar that is now used widely to study brain function and also to diagnose and plan treatment for cancer. She also developed another radiotracer, as these "tagged" molecules are called, that first showed that cocaine's distribution in the human brain parallels its effects on behavior.
Fowler played a central role in the development of a fluorine-18-labeled glucose molecule (FDG) enabling human brain glucose metabolism to be measured noninvasively. This positron-emitting molecule, together with positron emission tomography (PET) imaging, has become a mainstay for brain-imaging studies in schizophrenia, aging and cancer.
Another of her major accomplishments was the development of the first radiotracers to map monoamine oxidase (MAO), a brain enzyme that regulates the levels of other nerve-cell communication chemicals and one of the two major enzymes involved in neurotransmitter regulation in the brain and peripheral organs. Using these radiotracers, she discovered that smokers have reduced levels of MAO in their brains and lungs. This may account for some of the behavioral and epidemiological features of smoking, such as the high rate of smoking in individuals with depression and drug addiction, two conditions involving poor nerve-cell communication, and has led to many studies on reduced MAO and smoking.
Fowler holds eight patents for radiolabeling procedures. | 0 | Theoretical and Fundamental Chemistry |
It is a greenhouse gas with warming properties more than 7,000 times that of carbon dioxide over a 100-year period, and, as such, is one of the most potent greenhouse gasses ever discovered. Its concentration in the atmosphere is approximately 0.18 parts per trillion. The compound can persist in the atmosphere for up to 500 years. Sulfur hexafluoride, however, has a GWP of 23,900, which would make it much more powerful. | 1 | Applied and Interdisciplinary Chemistry |
Solvent–solute interactions are the same as solute–solute and solvent–solvent interactions, on average. Consequently, the enthalpy of mixing (solution) is zero and the change in Gibbs free energy on mixing is determined solely by the entropy of mixing. Hence the molar Gibbs free energy of mixing is
or for a two-component ideal solution
where m denotes molar, i.e., change in Gibbs free energy per mole of solution, and is the mole fraction of component . Note that this free energy of mixing is always negative (since each , each or its limit for must be negative (infinite)), i.e., ideal solutions are miscible at any composition and no phase separation will occur.
The equation above can be expressed in terms of chemical potentials of the individual components
where is the change in chemical potential of on mixing. If the chemical potential of pure liquid is denoted , then the chemical potential of in an ideal solution is
Any component of an ideal solution obeys Raoult's Law over the entire composition range:
where is the equilibrium vapor pressure of pure component and is the mole fraction of component in solution. | 0 | Theoretical and Fundamental Chemistry |
There are many design criteria which vary according to the type of disc and the required filtering capacity. The typical filter for extracting iron contains 12 ceramic filtering plates of the filtering elements (discs), which have a diameter of about 2705 mm, making the total filter surface 120 m. This filter is most suited to filter feed slurries with high solid concentrations (5-20% w/w) and particles ranging in size from 1–700 µm. The area of the filters available in the ceramic filter is up to 45 m, making them useful for metal and mineral concentrate processing.
The ceramic discs are available in two types, cast plate and membrane plate. The cast plate is a one piece ceramic plate with a homogeneous surface and a granulated core. The filter medium of the cast plate is the thick walls, separated by ceramic granules. These features form a rigid mechanical structure. The membrane plate type contains a thin membrane over a coarser core and a multi-layer porous structure made of aluminium oxide. The coarse part of the equipment provides mechanical strength to its structure while the intermediate layer acts as a membrane carrier. The outer layer membrane acts as a filtering layer. The filtration layer of the ceramic filter has uniform pores, which means that only a certain size of particles can be filtered by using vacuum ceramic filters. | 0 | Theoretical and Fundamental Chemistry |
The doubling time is slow, between 10 days to 2 weeks. This makes it difficult to grow enough sludge for a wastewater treatment reactor. Also the recovery time after the loss of sludge by accident is longer than in conventional nitrogen removal systems. On the other hand, this slow growing rate is an advantage due to the reduction of surplus sludge that needs to be removed and treated. Depending on the exact species, the optimum pH level is 8. Therefore, it can be necessary to adjust the pH of the wastewater by adding caustic. | 1 | Applied and Interdisciplinary Chemistry |
The strongly correlated quantum spin liquid (SCQSL) is a specific realization of a possible quantum spin liquid (QSL) representing a new type of strongly correlated electrical insulator (SCI) that possesses properties of heavy fermion metals with one exception: it resists the flow of electric charge. At low temperatures T the specific heat of this type of insulator is proportional to T, with n less or equal 1 rather than n=3, as it should be in the case of a conventional insulator whose heat capacity is proportional to T. When a magnetic field B is applied to SCI the specific heat depends strongly on B, contrary to conventional insulators. There are a few candidates of SCI; the most promising among them is Herbertsmithite, a mineral with chemical structure ZnCu(OH)Cl. | 0 | Theoretical and Fundamental Chemistry |
Alkylidenecyclopropanes more readily undergo C-C bond oxidative addition than cyclopropanes.
Following oxidative addition, 1,2-insertion mechanisms are common and reductive elimination yields the desired product. The 1,2-insertion step usually occurs with an alkyne, alkene, or allene and the final product is often a 5 or 7 membered ring. Six-membered rings may be formed after dimerization of the metallocyclobutane intermediate with another alkylidenecyclopropane substrate and subsequent reductive elimination. Common transition metals utilized with alkylidenecyclopropanes are nickel, rhodium, and palladium. It has been shown that the metallacyclobutane intermediate following oxidative addition to the distal C-C bond can isomerize. | 0 | Theoretical and Fundamental Chemistry |
The physical properties of N are quite different from other nuclei. Its properties along with several common nuclei are summarized in the below table.
From these data, one can see that at full enrichment, N is about one tenth (-27.126/267.522) as sensitive as H. | 0 | Theoretical and Fundamental Chemistry |
Direct photogeochemical catalysts act by absorbing light and subsequently transferring energy to reactants. | 0 | Theoretical and Fundamental Chemistry |
Léo Edmond Marion, (March 22, 1899 – July 16, 1979) was a Canadian organic chemist and academic administrator.
He was Vice-President of the National Research Council of Canada. From 1964 until 1965 he was President of the Royal Society of Canada. From 1965 until 1969, he was Dean of Faculty of Pure and Applied Science at the University of Ottawa. | 0 | Theoretical and Fundamental Chemistry |
Ada Florence Remfry Hitchins (26 June 1891 – 4 January 1972) was the principal research assistant of British chemist Frederick Soddy, who won the Nobel prize in 1921 for work on radioactive elements and the theory of isotopes. Hitchins isolated samples from uranium ores, taking precise and accurate measurements of atomic mass that provided the first experimental evidence for the existence of different isotopes. She also helped to discover the element protactinium, which Dmitri Mendeleev had predicted should occur in the periodic table between uranium and thorium. | 0 | Theoretical and Fundamental Chemistry |
The kilocalorie per mole is a unit to measure an amount of energy per number of molecules, atoms, or other similar particles. It is defined as one kilocalorie of energy (1000 thermochemical gram calories) per one mole of substance. The unit symbol is written kcal/mol or kcal⋅mol. As typically measured, one kcal/mol represents a temperature increase of one degree Celsius in one liter of water (with a mass of 1 kg) resulting from the reaction of one mole of reagents.
In SI units, one kilocalorie per mole is equal to 4.184 kilojoules per mole (kJ/mol), which comes to approximately joules per molecule, or about 0.043 eV per molecule. At room temperature (25 °C, 77 °F, or 298.15 K), one kilocalorie per mole is approximately equal to 1.688 units in the kT term of Boltzmann's equation.
Even though it is not an SI unit, the kilocalorie per mole is still widely used in chemistry and biology for thermodynamical quantities such as thermodynamic free energy, heat of vaporization, heat of fusion and ionization energy. This is due to a variety of factors, including the ease with which it can be calculated based on the units of measure typically employed in quantifying a chemical reaction, especially in aqueous solution. In addition, for many important biological processes, thermodynamic changes are on a convenient order of magnitude when expressed in kcal/mol. For example, for the reaction of glucose with ATP to form glucose-6-phosphate and ADP, the free energy of reaction is −4.0 kcal/mol using the pH = 7 standard state. | 0 | Theoretical and Fundamental Chemistry |
Benzyltrimethylammonium fluoride is a quaternary ammonium salt. It is commercially available as the hydrate. The compound is a source of organic-soluble fluoride to removal of silyl ether protecting groups. As is the case for tetra-n-butylammonium fluoride and most other quaternary ammonium fluorides, the compound cannot be obtained in anhydrous form. | 0 | Theoretical and Fundamental Chemistry |
At temperatures below the lambda point, helium shows the unique property of superfluidity. The fraction of the liquid that forms the superfluid component is a macroscopic quantum fluid. The helium atom is a neutral particle, so . Furthermore, when considering helium-4, the relevant particle mass is , so Eq. () reduces to
For an arbitrary loop in the liquid, this gives
Due to the single-valued nature of the wave function
with integer, we have
The quantity
is the quantum of circulation. For a circular motion with radius r
In case of a single quantum ()
When superfluid helium is put in rotation, Eq. () will not be satisfied for all loops inside the liquid unless the rotation is organized around vortex lines (as depicted in Fig. 2). These lines have a vacuum core with a diameter of about 1 Å (which is smaller than the average particle distance). The superfluid helium rotates around the core with very high speeds. Just outside the core (r = 1 Å), the velocity is as large as 160 m/s. The cores of the vortex lines and the container rotate as a solid body around the rotation axes with the same angular velocity. The number of vortex lines increases with the angular velocity (as shown in the upper half of the figure). Note that the two right figures both contain six vortex lines, but the lines are organized in different stable patterns. | 0 | Theoretical and Fundamental Chemistry |
(E,E)-2,4-Decadienal is an aromatic substance found in butter, cooked beef, fish, potato chips, roasted peanut, buckwheat and wheat bread crumb.
In an isolated state, it smells of deep fat flavor, characteristic of chicken aroma (at 10ppm). At lower concentration, it has the odor of citrus, orange or grapefruit.
It might be carcinogenic. It has been used as aroma in the EU, but use restrictions apply until the required data have been submitted. | 1 | Applied and Interdisciplinary Chemistry |
The propensity of a fluid to swirl is used to promote good fuel/air mixing in internal combustion engines.
In fluid mechanics and transport phenomena, an eddy is not a property of the fluid, but a violent swirling motion caused by the position and direction of turbulent flow. | 1 | Applied and Interdisciplinary Chemistry |
Besides simple strand displacement schemes, DNA computers have also been constructed using the concept of toehold exchange. In this system, an input DNA strand binds to a sticky end, or toehold, on another DNA molecule, which allows it to displace another strand segment from the molecule. This allows the creation of modular logic components such as AND, OR, and NOT gates and signal amplifiers, which can be linked into arbitrarily large computers. This class of DNA computers does not require enzymes or any chemical capability of the DNA. | 1 | Applied and Interdisciplinary Chemistry |
The enantioselectivity of CLAs derives from their ability to perturb the free energy barrier along with the reaction coordinate pathway that leads to either the R- or S- enantiomer. Ground state diastereomers and enantiomers are of equal energy in the ground state, and when reacted with an achiral Lewis acid, their diastereomeric intermediates, transition states, and products are also of equal energy. This leads to the production of racemic mixtures. However, when a CLA is used in the same reaction, the energetic barrier of formation of one diastereomer is less than that of another; the reaction is under kinetic control. If the difference in the energy barriers between the diastereomeric transition states are of sufficient magnitude, then a high enantiomeric excess of one isomer is observed. | 0 | Theoretical and Fundamental Chemistry |
In contrast to old H3 and H4, the old H2A and H2B histone proteins are released and degraded; therefore, newly assembled H2A and H2B proteins are incorporated into new nucleosomes. H2A and H2B are assembled into dimers which are then loaded onto nucleosomes by the nucleosome assembly protein-1 (NAP-1) which also assists with nucleosome sliding. The nucleosomes are also spaced by ATP-dependent nucleosome-remodeling complexes containing enzymes such as Isw1 Ino80, and Chd1, and subsequently assembled into higher order structure. | 1 | Applied and Interdisciplinary Chemistry |
A variety of fabrics such as wool, silk, nylon, polyester, polyacrylic, polyacetate, and polyurethane may be dyed with Glycoazodyes under moderate temperatures and pressures in aqueous solutions. First-generation Glycoazodyes dye cotton poorly. However, second-generation Glycoazodyes dye cotton effectively. Wool dyed with Glycoazodyes shows good fastness when exposed to the ISO 105-C06 washing and ISO 105 X12 rubbing tests.
Glycoazodyes vary in their water solubility. They may be soluble in cold to warm water and may dissolve after stirring or upon addition.
Minor variations in absorption spectra occur when Glycoazodye solutions are prepared, using water, acetone, or methanol solvents. Converting a parent azo dye to a Glycoazodye may produce a small hypsochromic shift in the absorption spectra. | 0 | Theoretical and Fundamental Chemistry |
An aluminide is a compound that has aluminium with other elements. Since aluminium is near the nonmetals on the periodic table, it can bond with metals differently from other metals. The properties of an aluminide are between those of a metal alloy and those of an ionic compound. | 1 | Applied and Interdisciplinary Chemistry |
In general, a catalyst is an agent that increases the speed of a chemical reaction without being consumed by a reaction. Thermodynamically, a catalyst lowers the activation energy required for a chemical reaction to take place. An electrocatalyst is a catalyst that affects the activation energy of an electrochemical reaction. Shown below is the activation energy of chemical reactions as it relates to the energies of products and reactants. The activation energy in electrochemical processes is related to the potential, i.e. voltage, at which a reaction occurs. Thus, electrocatalysts frequently change the potential at which oxidation and reduction processes are observed. Alternatively, an electrocatalyst can be thought of as an agent that facilitates a specific chemical interaction at an electrode surface. Given that electrochemical reactions occur when electrons are passed from one chemical species to another, favorable interactions at an electrode surface increase the likelihood of electrochemical transformations occurring, thus reducing the potential required to achieve these transformations.
Electrocatalysts can be evaluated according to three figures of merit: activity, stability, and selectivity. The activity of electrocatalysts can be assessed quantitatively by understanding how much current density is generated, and therefore how fast a reaction is taking place, for a given applied potential. This relationship is described with the Tafel equation. In assessing the stability of electrocatalysts, the ability of catalysts to withstand the potentials at which transformations are occurring is crucial. The selectivity of electrocatalysts refers to their preferential interaction with particular substrates, and their generation of a single product. Selectivity can be quantitatively assessed through a selectivity coefficient, which compares the response of the material to the desired analyte or substrate with the response to other interferents.
In many electrochemical systems, including galvanic cells, fuel cells and various forms of electrolytic cells, a drawback is that they can suffer from high activation barriers. The energy diverted to overcome these activation barriers is transformed into heat. In most exothermic combustion reactions this heat would simply propagate the reaction catalytically. In a redox reaction, this heat is a useless byproduct lost to the system. The extra energy required to overcome kinetic barriers is usually described in terms of low faradaic efficiency and high overpotentials. In these systems, each of the two electrodes and its associated half-cell would require its own specialized electrocatalyst.
Half-reactions involving multiple steps, multiple electron transfers, and the evolution or consumption of gases in their overall chemical transformations, will often have considerable kinetic barriers. Furthermore, there is often more than one possible reaction at the surface of an electrode. For example, during the electrolysis of water, the anode can oxidize water through a two electron process to hydrogen peroxide or a four electron process to oxygen. The presence of an electrocatalyst could facilitate either of the reaction pathways. | 0 | Theoretical and Fundamental Chemistry |
The purpose of this method is to reduce carbon content from steel. This process is suitable for secondary steelmaking industry which recycling steel scrap that has variety of carbon content in their feedstock. This method aim to replace current conventional method that utilizing Basic Oxygen Furnace (BOF) to reduce carbon content of iron by blowing oxygen to make it react with carbon and forming CO.
In electrorefining, decarburization process happened in electrochemical cell that composed of inert electrode, slag and steel. During the process, current passing through the cell and made slag and steel melted. Oxygen ion from slag decompose and oxidize carbon on steel and to form CO. That decarburizing reaction is occurred in three steps as follow. (ads) means adsorbed intermediate
The total reaction from this cell is following this scheme
The SiO is come from the slag, based on the reaction above, beside producing CO gas, this method also producing pure silicon (depending on the slag). The benefit of this direct decarburization process is it does not produce CO but CO which is not considered as greenhouse gas. | 1 | Applied and Interdisciplinary Chemistry |
Other key properties of an injector include the fluid inlet pressure requirements i.e. whether it is lifting or non-lifting.
In a non-lifting injector, positive inlet fluid pressure is needed e.g. the cold water input is fed by gravity.
The steam-cone minimal orifice diameter is kept larger than the combining cone minimal diameter. The non-lifting Nathan 4000 injector used on the Southern Pacific 4294 could push 12,000 US gallons (45,000 L) per hour at 250 psi (17 bar).
The lifting injector can operate with negative inlet fluid pressure i.e. fluid lying below the level of the injector. It differs from the non-lifting type mainly in the relative dimensions of the nozzles. | 1 | Applied and Interdisciplinary Chemistry |
Radiative cooling is commonly experienced on cloudless nights, when heat is radiated into outer space from Earth's surface, or from the skin of a human observer. The effect is well-known among amateur astronomers.
The effect can be experienced by comparing skin temperature from looking straight up into a cloudless night sky for several seconds, to that after placing a sheet of paper between the face and the sky. Since outer space radiates at about a temperature of , and the sheet of paper radiates at about (around room temperature), the sheet of paper radiates more heat to the face than does the darkened cosmos. The effect is blunted by Earth's surrounding atmosphere, and particularly the water vapor it contains, so the apparent temperature of the sky is far warmer than outer space. The sheet does not block the cold, but instead reflects heat to the face and radiates the heat of the face that it just absorbed.
The same radiative cooling mechanism can cause frost or black ice to form on surfaces exposed to the clear night sky, even when the ambient temperature does not fall below freezing. | 0 | Theoretical and Fundamental Chemistry |
Mohamed Osman Baloola ( born April 14, 1981) is a Sudanese scientist and inventor who was named among The Worlds 500 Most influential Arabs in 2012 and 2013' for his work on diabetes. Baloola has been a teaching assistant of biomedical engineering at the Ajman University of Science and Technology since 2010. He won a science and innovation award at the Arabian Business Awards 2011, in the Amrani hotel at Burj Khalifa in Dubai. He won Dh40,000 (11,000 US) during a Sharjah television competition for his invention of a remote monitoring and control system for diabetes patients via mobile phone. | 0 | Theoretical and Fundamental Chemistry |
FLiNaK is the name of the ternary eutectic alkaline metal fluoride salt mixture LiF-NaF-KF (46.5-11.5-42 mol %). It has a melting point of 462 °C and a boiling point of 1570 °C. It is used as electrolyte for the electroplating of refractory metals and compounds like titanium, tantalum, hafnium, zirconium and their borides. FLiNaK also could see potential use as a coolant in the very high temperature reactor, a type of nuclear reactor. | 0 | Theoretical and Fundamental Chemistry |
The surface morphology and shape of the cross-section can be observed via scanning electron microscope (SEM) imaging after removal of solvent. Also, environmental scanning electron microscope (ESEM) can be used to observe wet hydrogel fibers. But different treatments will affect the surface morphology of the hydrogel fiber drastically. If the hydrogel fiber was dried directly, a smooth surface would be obtained because of the collapse of the polymer network after the removal of the solvent. If the hydrogel fiber was lyophilized, a porous surface will usually be found due to the pore-forming effect of the ice crystal. ESEM can directly observe the surface morphology. The resulting image usually indicates a smooth surface with some wrinkled formed due to the gradual loss of water. | 0 | Theoretical and Fundamental Chemistry |
β-Hydroxy β-methylbutyryl-coenzyme A (HMB-CoA), also known as 3-hydroxyisovaleryl-CoA, is a metabolite of -leucine that is produced in the human body. Its immediate precursors are β-hydroxy β-methylbutyric acid (HMB) and β-methylcrotonoyl-CoA (MC-CoA). It can be metabolized into HMB, MC-CoA, and HMG-CoA in humans. | 1 | Applied and Interdisciplinary Chemistry |
The spin and dip coating methods are simple methods for nanoparticle deposition. They are useful tools especially in creating self-assembled layers and films where the packing density isn't critical. Accurate and vibration-free sample withdrawal speeds can be used to have control over the film thickness. Creating high density monolayers is typically very difficult since the methods are lacking the packing density control. Also, the volume of nanoparticle suspension required for both spin coating and dip coating is rather big which may be an issue when using expensive nanoparticle materials. | 0 | Theoretical and Fundamental Chemistry |
Eco pickled surface (EPS) is a process applied to hot rolled sheet steel to remove all surface oxides (mill scale) and clean the steel surface. Steel which has undergone the EPS process acquires a high degree of resistance to subsequent development of surface oxide (rust), so long as it does not come into direct contact with moisture. EPS was developed by The Material Works, Ltd., which has filed several patent applications covering the process. It is primarily intended to be a replacement of the acid pickling process wherein steel strip is immersed in solutions of hydrochloric and sulfuric acids to chemically remove oxides. | 1 | Applied and Interdisciplinary Chemistry |
In molecular biology, methylation induced premeiotically (MIP) is a process by which cytosines within repeated DNA sequences are de novo methylated prior to the sexual cycle. This process was first described in the ascomycete Ascobolus immersens. MIP is dependent upon the gene masc1 which encodes a cytosine methyltransferase-like protein.
At least one major function of the process appears to be genome defense. Related functions have been found in other fungi, including Neurospora and Aspergillus species. | 1 | Applied and Interdisciplinary Chemistry |
With the availability of high-performance GPU-based implementations, the former disadvantage of limited interactivity is no longer present. | 1 | Applied and Interdisciplinary Chemistry |
:V09AX01 Indium (In) pentetic acid
:V09AX03 Iodine (I) 2β-carbomethoxy-3β-(4-iodophenyl)-tropane
:V09AX04 Flutemetamol (F)
:V09AX05 Florbetapir (F)
:V09AX06 Florbetaben (F)
:V09AX07 Flortaucipir (F) | 1 | Applied and Interdisciplinary Chemistry |
Dispersing is the principal goal in the use of detergents, which the liquid bath is water (detergents also are used as emulsifiers in some applications). Laundry detergents encase dirt and grime in miscelles, which naturally disperse. | 0 | Theoretical and Fundamental Chemistry |
Plants deficient in the IMMUTANS gene that encodes the oxidase are especially susceptible to photooxidative stress during early plastid development. The knockout plants exhibit a phenotype of variegated leaves with white patches that indicate a lack of pigmentation or photodamage. This effect is enhanced with increased light and temperature during plant development. The lack of plastid terminal oxidase indirectly causes photodamage during plastid development because protective carotenoids are not synthesized without the oxidase.
The enzyme is also thought to act as a safety valve for stress conditions in the photosynthetic apparatus. By providing an electron sink when the plastoquinone pool is over-reduced, the oxidase is thought to protect photosystem II from oxidative damage. Knockouts for Rubisco and photosystem II complexes, which would experience more photodamage than normal, exhibit an upregulation of plastid terminal oxidase. This effect is not universal because it requires plants to have additional PTOX regulation mechanisms. While many studies agree with the stress-protective role of the enzyme, one study showed that overexpression of PTOX increases the production of reactive oxygen species and causes more photodamage than normal. This finding suggests that an efficient antioxidant system is required for the oxidase to function as a safety valve for stress conditions and that it is more important during chloroplast biogenesis than in the regular functioning of the chloroplast. | 0 | Theoretical and Fundamental Chemistry |
Cleaner production is a preventive, company-specific environmental protection initiative. It is intended to minimize waste and emissions and maximize product output. By analysing the flow of materials and energy in a company, one tries to identify options to minimize waste and emissions out of industrial processes through source reduction strategies. Improvements of organisation and technology help to reduce or suggest better choices in use of materials and energy, and to avoid waste, waste water generation, and gaseous emissions, and also waste heat and noise. | 1 | Applied and Interdisciplinary Chemistry |
Drugs have long been considered crucial targets for transmitter-gated ion channels. The majority of medications utilized to treat schizophrenia, anxiety, depression, and sleeplessness work at chemical synapses, and many of these pharmaceuticals function by binding to transmitter-gated channels. For instance, some drugs like barbiturates and tranquilizers bind to GABA receptors and enhance the inhibitory effect of GABA neurotransmitter. Thus, reduced concentration of GABA enables the opening of Cl- channels.
Furthermore, psychoactive drugs could potentially target many other synaptic signalling machinery components. In fact, numerous neurotransmitters are released by Na+-driven carriers and are subsequently removed from the synaptic cleft. By inhibiting such carriers, synaptic transmission is strengthened as the action of the transmitter is prolonged. For example, Prozac is one of antidepressant medications that works by preventing the absorption of serotonin neurotransmitter. Also, other antidepressants operate by inhibiting the reabsorption of both serotonin and norepinephrine. | 1 | Applied and Interdisciplinary Chemistry |
While a verdant Arctic Ocean is a viable working model, skeptical scientists point out that it would be possible for Azolla colonies in river deltas or freshwater lagoons to be swept into the Arctic Ocean by strong currents, removing the necessity for a freshwater layer. | 1 | Applied and Interdisciplinary Chemistry |
The fluorescence signals emitted from phycoerythrin and phycocyanin have made them suitable for use as indicators to detect cyanotoxins such as microcystins in drinking water. A study examined the nature of the biliproteins fluorescence signals regarding their real-time character, sensitivity and the biliproteins behaviour in different treatment stages (of water) in comparison to microcystins. The fluorescence signals' real-time character was confirmed by fluorescence measurements, as they can be carried out without having to pre-concentrate the biliproteins. If the ratio of biliprotein to microcystin is above 1, the fluorescence signals can estimate very low concentrations of microcystins. A test conducted in 2009 compared the behaviour of both biliproteins and selected microcystins MC-LR and MC-RR during water treatment. The test results showed that the biliproteins have an early warning function against microcystins in conventional treatment stages that use pre-oxidation with permanganate, activated carbon and chlorination. However, the early warning function does not occur when chlorine dioxide is used as a pre-oxidant or final disinfectant. It is important for the biliprotein/toxin ratio of raw water to be known in order to use the biliproteins for control measurements in drinking water treatment. | 1 | Applied and Interdisciplinary Chemistry |
In geology, a redox buffer is an assemblage of minerals or compounds that constrains oxygen fugacity as a function of temperature. Knowledge of the redox conditions (or equivalently, oxygen fugacities) at which a rock forms and evolves can be important for interpreting the rock history. Iron, sulfur, and manganese are three of the relatively abundant elements in the Earth's crust that occur in more than one oxidation state. For instance, iron, the fourth most abundant element in the crust, exists as native iron, ferrous iron (Fe), and ferric iron (Fe). The redox state of a rock affects the relative proportions of the oxidation states of these elements and hence may determine both the minerals present and their compositions. If a rock contains pure minerals that constitute a redox buffer, then the oxygen fugacity of equilibration is defined by one of the curves in the accompanying fugacity-temperature diagram. | 0 | Theoretical and Fundamental Chemistry |
It was first developed and utilized by Roy Britten and his colleagues at the Carnegie Institution of Washington in the 1960s. Of particular note, it was through Ct analysis that the redundant (repetitive) nature of eukaryotic genomes was first discovered. However, it wasn't until the breakthrough DNA reassociation kinetics experiments of Britten and his colleagues that it was shown that not all DNA coded for genes. In fact, their experiments demonstrated that the majority of eukaryotic genomic DNA is composed of repetitive, non-coding elements. | 1 | Applied and Interdisciplinary Chemistry |
The Washoe process, a variation of pan amalgamation, was developed in the 1860s by Almarin B. Paul and others, to work the ore from the Comstock Lode in Nevada, United States (Washoe was an early name for the area and the local tribe who still exists today; see Washoe Valley). In the Washoe process, the copper pans were replaced by iron tanks with mechanical agitators. Each tank ("pan") was circular, and commonly held 1,200 to 1,500 pounds of ore that had been crushed to sand size. Water was added to make a pulp, and 60 to 70 pounds of mercury, along with one-half to three pounds each of salt (sodium chloride) and bluestone (copper(II) sulfate) were also added. A circular iron plate called a muller was mounted on a vertical shaft and lowered into the pan, and was rotated to provide both agitation and additional grinding. Heat was delivered to the pans by steam pipes. The iron filings worn from the muller and pan proved to be an essential ingredient in the process. | 1 | Applied and Interdisciplinary Chemistry |
The Elbs reaction enables the synthesis of condensed aromatic systems. As already demonstrated by Elbs in 1884 it is possible to obtain anthracene through dehydration. Larger aromatic systems like pentacene are also feasible. This reaction does not take place in a single step but leads first to dihydropentacene that is dehydrogenated in a second step with copper as a catalyst.
The acyl compounds required for this reaction can be obtained through a Friedel-Crafts acylation with aluminum chloride.
The Elbs reaction is sometimes accompanied by elimination of substituents and can be unsuited for substituted polyaromatics. | 0 | Theoretical and Fundamental Chemistry |
The process of light ion acceleration using electrostatic fields and deuterium ions to produce fusion in solid deuterated targets was first demonstrated by Cockcroft and Walton in 1932 (see Cockcroft–Walton generator). That process is used in miniaturized versions of their original accelerator, in the form of small sealed tube neutron generators, for petroleum exploration.
The process of pyroelectricity has been known from ancient times. The first use of a pyroelectric field to accelerate deuterons was in a 1997 experiment conducted by Drs. V.D. Dougar Jabon, G.V. Fedorovich, and N.V. Samsonenko. This group was the first to utilize a lithium tantalate () pyroelectric crystal in fusion experiments.
The novel idea with the pyroelectric approach to fusion is in its application of the pyroelectric effect to generate accelerating electric fields. This is done by heating the crystal from −34 °C to +7 °C over a period of a few minutes.
Nuclear D-D fusion driven by pyroelectric crystals was proposed by Naranjo and Putterman in 2002. It was also discussed by Brownridge and Shafroth in 2004. The possibility of using pyroelectric crystals in a neutron production device (by D-D fusion) was proposed in a conference paper by Geuther and Danon in 2004 and later in a publication discussing electron and ion acceleration by pyroelectric crystals. None of these later authors had prior knowledge of the earlier 1997 experimental work conducted by Dougar Jabon, Fedorovich, and Samsonenko which mistakenly believed that fusion occurred within the crystals. The key ingredient of using a tungsten needle to produce sufficient ion beam current for use with a pyroelectric crystal power supply was first demonstrated in the 2005 Nature paper, although in a broader context tungsten emitter tips have been used as ion sources in other applications for many years. In 2010, it was found that tungsten emitter tips are not necessary to increase the acceleration potential of pyroelectric crystals; the acceleration potential can allow positive ions to reach kinetic energies between 300 and 310 keV. | 0 | Theoretical and Fundamental Chemistry |
T MRI has been used to image tissues such as cartilage, intervertebral discs, brain, and heart, as well as certain types of cancers. | 0 | Theoretical and Fundamental Chemistry |
Light-emitting diodes (LEDs) can be manufactured to emit radiation in the ultraviolet range. In 2019, following significant advances over the preceding five years, UV‑A LEDs of 365 nm and longer wavelength were available, with efficiencies of 50% at 1.0 W output. Currently, the most common types of UV LEDs are in 395 nm and 365 nm wavelengths, both of which are in the UV‑A spectrum. The rated wavelength is the peak wavelength that the LEDs put out, but light at both higher and lower wavelengths are present.
The cheaper and more common 395 nm UV LEDs are much closer to the visible spectrum, and give off a purple color. Other UV LEDs deeper into the spectrum do not emit as much visible light LEDs are used for applications such as UV curing applications, charging glow-in-the-dark objects such as paintings or toys, and lights for detecting counterfeit money and bodily fluids. UV LEDs are also used in digital print applications and inert UV curing environments. Power densities approaching 3 W/cm (30 kW/m) are now possible, and this, coupled with recent developments by photo-initiator and resin formulators, makes the expansion of LED cured UV materials likely.
UV‑C LEDs are developing rapidly, but may require testing to verify effective disinfection. Citations for large-area disinfection are for non-LED UV sources known as germicidal lamps. Also, they are used as line sources to replace deuterium lamps in liquid chromatography instruments. | 0 | Theoretical and Fundamental Chemistry |
Alternative polyadenylation (APA) is a regulatory mechanism that forms multiple 3' end on mRNA.
APA isoforms from the same gene can encode different proteins and/or contain different 3' untranslated regions (UTRs). Deregulation of APA has been associated with a number of human diseases. Since longer UTRs have more binding sites for microRNAs and/or RNA-binding proteins in comparison to shorter UTRs, APA require different stability, translation efficiency, and/or intracellular localization.
Mammalian PASs have a number of key cis elements.
* A(A/U)AAA hexamer
* U/GU-rich downstream element (DSE)
* U-rich upstream auxiliary elements (USEs)
* Upstream sequences conforming to the consensus UGUA
PAS sequences are variable, and many PASs lack one or more cis elements. PAS recognition is accomplished by protein-RNA interactions.
CPSF synergistically binds to the AAUAAA hexamer and CstF synergistically binds to the downstream element (DSE). The CFI complex binds to the UGUA motifs. CPSF, CstF, and CFI bind directly to RNA. They also recruit other proteins such as CFII, symplekin, and the poly(A) polymerase (PAP) to assemble the mRNA 3' processing complex, also known as the cleavage and polyadenylation complex. The assembly of these factors are facilitated by the C-terminal domain (CTD) of the RNA polymerase II (RNAP II) large subunit. The CTD provides a landing pad for mRNA processing factors. | 1 | Applied and Interdisciplinary Chemistry |
The electrical conduction system of the heart has been robustly established. However, newer research has been challenging some of the previously accepted models. The role of ephaptic coupling in cardiac cells is becoming more apparent. One author even goes so far as to say, “While previously viewed as a possible alternative to electrotonic coupling, ephaptic coupling has since come to be viewed as operating in tandem with gap junctions, helping sustain conduction when gap junctional coupling is compromised.” Ephaptic interactions among cardiac cells help fill in the gaps that electrical synapses alone cannot account for. The proximity of sodium channels to gap junction plaques has been shown to relate to their effectiveness in driving ephaptic coupling action potential transmission. There are also a number of mathematical models that now incorporate ephaptic coupling into predictions about electrical conductance in the heart. Experimental work suggests that sodium channel-rich nanodomains located at sites of close contact between cardiac myocytes may constitute functional units of ephaptic coupling and selective disruption of these nanodomains resulted in arrhythmogenic conduction slowing, suggesting an important role for ephaptic coupling in the heart. Potential ephaptic connections are now being considered in heart therapeutics. | 1 | Applied and Interdisciplinary Chemistry |
The sol–gel process is a wet-chemical technique used for the fabrication of both glassy and ceramic materials. In this process, the sol (or solution) evolves gradually towards the formation of a gel-like network containing both a liquid phase and a solid phase. Typical precursors are metal alkoxides and metal chlorides, which undergo hydrolysis and polycondensation reactions to form a colloid. The basic structure or morphology of the solid phase can range anywhere from discrete colloidal particles to continuous chain-like polymer networks.
The term colloid is used primarily to describe a broad range of solid-liquid (and/or liquid-liquid) mixtures, all of which contain distinct solid (and/or liquid) particles which are dispersed to various degrees in a liquid medium. The term is specific to the size of the individual particles, which are larger than atomic dimensions but small enough to exhibit Brownian motion. If the particles are large enough, then their dynamic behavior in any given period of time in suspension would be governed by forces of gravity and sedimentation. But if they are small enough to be colloids, then their irregular motion in suspension can be attributed to the collective bombardment of a myriad of thermally agitated molecules in the liquid suspending medium, as described originally by Albert Einstein in his dissertation. Einstein concluded that this erratic behavior could adequately be described using the theory of Brownian motion, with sedimentation being a possible long-term result. This critical size range (or particle diameter) typically ranges from tens of angstroms (10 m) to a few micrometres (10 m).
*Under certain chemical conditions (typically in base-catalyzed sols), the particles may grow to sufficient size to become colloids, which are affected both by sedimentation and forces of gravity. Stabilized suspensions of such sub-micrometre spherical particles may eventually result in their self-assembly—yielding highly ordered microstructures reminiscent of the prototype colloidal crystal: precious opal.
*Under certain chemical conditions (typically in acid-catalyzed sols), the interparticle forces have sufficient strength to cause considerable aggregation and/or flocculation prior to their growth. The formation of a more open continuous network of low density polymers exhibits certain advantages with regard to physical properties in the formation of high performance glass and glass/ceramic components in 2 and 3 dimensions.
In either case (discrete particles or continuous polymer network) the sol evolves then towards the formation of an inorganic network containing a liquid phase (gel). Formation of a metal oxide involves connecting the metal centers with oxo (M-O-M) or hydroxo (M-OH-M) bridges, therefore generating metal-oxo or metal-hydroxo polymers in solution.
In both cases (discrete particles or continuous polymer network), the drying process serves to remove the liquid phase from the gel, yielding a micro-porous amorphous glass or micro-crystalline ceramic. Subsequent thermal treatment (firing) may be performed in order to favor further polycondensation and enhance mechanical properties.
With the viscosity of a sol adjusted into a proper range, both optical quality glass fiber and refractory ceramic fiber can be drawn which are used for fiber optic sensors and thermal insulation, respectively. In addition, uniform ceramic powders of a wide range of chemical composition can be formed by precipitation. | 0 | Theoretical and Fundamental Chemistry |
Chemfluence, is a national level technical symposium (Technical and Cultural Events) organized annually by the Association of Chemical Engineers, Department of Chemical Engineering, Alagappa College of Technology, Anna University every year since 1994.
With an array of events spread across three days it seeks to provide a platform for budding Chemical Engineers across the nation to show off their technical prowess and to attain their full intellectual potential.
With innovation as inspiration and technical knowledge as a tool, Chemfluence aims at bringing a complete transformation to the very grassroots of the field. Chemfluence gives an opportunity for engineering students to look beyond their course and curriculum, to roll back their sleeves, with the technical wand in their hands and do some real magic. | 1 | Applied and Interdisciplinary Chemistry |
The serendipity discovery of dye-ligand ability is from a blue dye called blue dextran. The blue dye is used as a void volume (V) marker for a gel filtration column. It has shown that the dye has a property to bind to some certain proteins like pyruvate kinase and elute out with the void volume. Later on, it was found that "cibacron blue FG3-A", reactive dye link to dextran, is responsible for the interaction with the proteins. | 0 | Theoretical and Fundamental Chemistry |
An autoantigen is usually a self-protein or protein complex (and sometimes DNA or RNA) that is recognized by the immune system of patients with a specific autoimmune disease. Under normal conditions, these self-proteins should not be the target of the immune system, but in autoimmune diseases, their associated T cells are not deleted and instead attack. | 1 | Applied and Interdisciplinary Chemistry |
Ernest Ludwig Eliel (December 28, 1921 – September 18, 2008) was an organic chemist born in Cologne, Germany. Among his awards were the Priestley Medal in 1996 and the NAS Award for Chemistry in Service to Society in 1997.
When the Nazis came to power, he left Germany and moved to Scotland, then Canada, then Cuba. He received his B.S. from the University of Havana in 1946. He moved to the United States in 1946 and taught at the University of Notre Dame from 1948. In 1972 he moved to be the W.R. Kenan, Jr. Professor of Chemistry at the University of North Carolina at Chapel Hill until his retirement in 1993. Eliel was elected a Fellow of the American Academy of Arts and Sciences in 1980. In 1981, Eliel became a founding member of the World Cultural Council. He served as president of the American Chemical Society in 1992. In 1995 he received the George C. Pimentel Award in Chemical Education, and in 1996 he was awarded the Priestley Medal of the American Chemical Society. He died in Chapel Hill, North Carolina.
His research focussed on the stereochemistry and conformational analysis of flexible organic molecules, including derivatives of cyclohexane and saturated heterocyclic rings, using nuclear magnetic resonance spectroscopy (NMR) extensively. His 1962 textbook Stereochemistry of Carbon Compounds influenced generations of organic chemists. The most recent edition is Stereochemistry of Organic Compounds, co-authored in 1994 with Samuel H. Wilen. | 0 | Theoretical and Fundamental Chemistry |
A more complex use of reporter genes on a large scale is in two-hybrid screening, which aims to identify proteins that natively interact with one another in vivo. | 1 | Applied and Interdisciplinary Chemistry |
Early records of the discovery of polymorphism credit Eilhard Mitscerlich and Jöns Jacob Berzelius for their studies of phosphates and arsenates in the early 1800s. The studies involved measuring the interfacial angles of the crystals to show that chemically identical salts could have two different forms. Mitscerlich originally called this discovery isomorphism. The measurement of crystal density was also used by Wilhelm Ostwald and expressed in Ostwald's Ratio.
The development of the microscope enhanced observations of polymorphism and aided Moritz Ludwig Frankenheim’s studies in the 1830s. He was able to demonstrate methods to induce crystal phase changes and formally summarized his findings on the nature of polymorphism. Soon after, the more sophisticated polarized light microscope came into use, and it provided better visualization of crystalline phases allowing crystallographers to distinguish between different polymorphs. The hot stage was invented and fitted to a polarized light microscope by Otto Lehmann in about 1877. This invention helped crystallographers determine melting points and observe polymorphic transitions.
While the use of hot stage microscopes continued throughout the 1900s, thermal methods also became commonly used to observe the heat flow that occurs during phase changes such as melting and polymorphic transitions. One such technique, differential scanning calorimetry (DSC), continues to be used for determining the enthalpy of polymorphic transitions.
In the 20th century, X-ray crystallography became commonly used for studying the crystal structure of polymorphs. Both single crystal x-ray diffraction and powder x-ray diffraction techniques are used to obtain measurements of the crystal unit cell. Each polymorph of a compound has a unique crystal structure. As a result, different polymorphs will produce different x-ray diffraction patterns.
Vibrational spectroscopic methods came into use for investigating polymorphism in the second half of the twentieth century and have become more commonly used as optical, computer, and semiconductor technologies improved. These techniques include infrared (IR) spectroscopy, terahertz spectroscopy and Raman spectroscopy. Mid-frequency IR and Raman spectroscopies are sensitive to changes in hydrogen bonding patterns. Such changes can subsequently be related to structural differences. Additionally, terahertz and low frequency Raman spectroscopies reveal vibrational modes resulting from intermolecular interactions in crystalline solids. Again, these vibrational modes are related to crystal structure and can be used to uncover differences in 3-dimensional structure among polymorphs. | 0 | Theoretical and Fundamental Chemistry |
Herbivores are dependent on plants for food and have evolved mechanisms to obtain this food despite the evolution of a diverse arsenal of plant defenses. Herbivore adaptations to plant defense have been likened to offensive traits and consist of adaptations that allow increased feeding and use of a host plant. Relationships between herbivores and their host plants often result in reciprocal evolutionary change, called co-evolution. When an herbivore eats a plant, it selects for plants that can mount a defensive response. In cases where this relationship demonstrates specificity (the evolution of each trait is due to the other) and reciprocity (both traits must evolve), the species are thought to have co-evolved.
The "escape and radiation" mechanism for co-evolution presents the idea that adaptations in herbivores and their host plants have been the driving force behind speciation and have played a role in the radiation of insect species during the age of angiosperms. Some herbivores have evolved ways to hijack plant defenses to their own benefit by sequestering these chemicals and using them to protect themselves from predators. Plant defenses against herbivores are generally not complete, so plants also tend to evolve some tolerance to herbivory. | 1 | Applied and Interdisciplinary Chemistry |
The South Pacific Gyre, like its northern counterpart, is one of the largest ecosystems on Earth with an area that accounts for around 10% of the global ocean surface area. Within this massive area is Point Nemo, the location on Earth that is farthest away from all continental landmass (2,688 km away from the closest land). The remoteness of this gyre complicates sampling, causing this gyre to be historically under sampled in oceanographic datasets. At the northern boundary of the South Pacific Gyre, the South Equatorial Current flows west towards southeast Asia and Australia. There, it turns south as it flows in the East Australian Current, a western boundary current. The Antarctic Circumpolar Current again returns the water to the east. The flow turns north along the western coast of South America in the Humboldt Current, the eastern boundary current that completes the South Pacific Gyre circulation. Like the North Pacific Gyre, the South Pacific Gyre has an elevated concentration of plastic waste near the center, termed the South Pacific garbage patch. Unlike the North Pacific garbage patch which was first described in 1988, the South Pacific garbage patch was discovered much more recently in 2016 (a testament to the extreme remoteness of the South Pacific Gyre). | 1 | Applied and Interdisciplinary Chemistry |
Cell encapsulation is a possible solution to graft rejection in tissue engineering applications. Cell microencapsulation technology involves immobilization of cells within a polymeric semi-permeable membrane. It permits the bidirectional diffusion of molecules such as the influx of oxygen, nutrients, growth factors etc. essential for cell metabolism and the outward diffusion of waste products and therapeutic proteins. At the same time, the semi-permeable nature of the membrane prevents immune cells and antibodies from destroying the encapsulated cells, regarding them as foreign invaders.
Cell encapsulation could reduce the need for long-term use of immunosuppressive drugs after an organ transplant to control side effects. | 1 | Applied and Interdisciplinary Chemistry |
In figure at left, the various segments that form the epitope have been shown to be continuously collinear, meaning that they have been shown as sequential; however, for the situation being discussed here (i.e., the antigen recognition by the B cell), this explanation is too simplistic. Such epitopes are known as sequential or linear epitopes, as all the amino acids on them are in the same sequence (line). This mode of recognition is possible only when the peptide is small (about six to eight amino acids long), and is employed by the T cells (T lymphocytes).
However, the B memory/naive cells recognize intact proteins present on the pathogen surface. In this situation, the protein in its tertiary structure is so greatly folded that some loops of amino acids come to lie in the interior of the protein, and the segments that flank them may lie on the surface. The paratope on the B cell receptor comes in contact only with those amino acids that lie on the surface of the protein. The surface amino acids may actually be discontinuous in the proteins primary structure, but get juxtaposed owing to the complex protein folding patterns (as in the adjoining figure). Such epitopes are known as conformational' epitopes and tend to be longer (15–22 amino acid residues) than the linear epitopes. Likewise, the antibodies produced by the plasma cells belonging to the same clone would bind to the same conformational epitopes on the pathogen proteins.
The binding of a specific antigen with corresponding BCR molecules results in increased production of the MHC-II molecules. This assumes significance as the same does not happen when the same antigen would be internalized by a relatively nonspecific process called pinocytosis, in which the antigen with the surrounding fluid is "drunk" as a small vesicle by the B cell. Hence, such an antigen is known as a nonspecific antigen and does not lead to activation of the B cell, or subsequent production of antibodies against it. | 1 | Applied and Interdisciplinary Chemistry |
Photochlorination is one of the largest implementations of photochemistry to organic synthesis. The photon is however not absorbed by the organic compound, but by chlorine. Photolysis of Cl gives chlorine atoms, which abstract H atoms from hydrocarbons, leading to chlorination. | 0 | Theoretical and Fundamental Chemistry |
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