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Recent algae blooms in Lake Erie have been fed primarily by agricultural runoff and have led to warnings for some people in Canada and Ohio not to drink their water. The International Joint Commission has called on United States and Canada to drastically reduce phosphorus loads into Lake Erie to address the threat. | 0 | Theoretical and Fundamental Chemistry |
The endocannabinoid system (ECS) is a biological system composed of endocannabinoids, which are endogenous lipid-based retrograde neurotransmitters that bind to cannabinoid receptors, and cannabinoid receptor proteins that are expressed throughout the vertebrate central nervous system (including the brain) and peripheral nervous system. The endocannabinoid system remains under preliminary research, but may be involved in regulating physiological and cognitive processes, including fertility, pregnancy, pre- and postnatal development, various activity of immune system, appetite, pain-sensation, mood, and memory, and in mediating the pharmacological effects of cannabis. The ECS plays an important role in multiple aspects of neural functions, including the control of movement and motor coordination, learning and memory, emotion and motivation, addictive-like behavior and pain modulation, among others.
Two primary cannabinoid receptors have been identified: CB1, first cloned (or isolated) in 1990; and CB2, cloned in 1993. CB1 receptors are found predominantly in the brain and nervous system, as well as in peripheral organs and tissues, and are the main molecular target of the endogenous partial agonist, anandamide, as well as exogenous tetrahydrocannabinol, the most known active component of cannabis. Endocannabinoid 2-arachidonoylglycerol (2-AG), which was found to be two and three orders of magnitude more abundant in mammalian brain than anandamide, acts as a full agonist at both CB receptors.
The endocannabinoid system is sometimes referred to as the endocannabinoidome or expanded endocannabinoid system. | 1 | Applied and Interdisciplinary Chemistry |
In medieval Europe, medicinal herbs and plants were cultivated in monastery and nunnery gardens beginning about the 8th century. Charlemagne gave orders for the collection of medicinal plants to be grown systematically in his royal garden. This royal garden was an important precedent for botanical gardens and physic gardens that were established in the 16th century. It was also the beginning of the study of botany as a separate discipline. In about the 12th century, medicine and pharmacy began to be taught in universities.
Shabbethai Ben Abraham, better known as Shabbethai Donnolo, (913–c.982) was a 10th-century Italian Jew and the author of an early Hebrew text, Antidotarium. It consisted of detailed drug descriptions, medicinal remedies, practical methods for preparing medicine from roots. It was a veritable glossary of herbs and drugs used during the medieval period. Donnollo was widely travelled and collected information from Arabic, Greek and Roman sources.
In the Early and High Middle Ages Nestorian Christians were banished for their heretical views that they carried to Asia Minor. The Greek text was translated into Syriac when pagan Greek scholars fled east after Constantine’s conquest of Byzantium,
Stephanos (son of Basilios, a Christian living in Baghdad under the Khalif Motawakki) made an Arabic translation of De Materia Medica from the Greek in 854. In 948 the Byzantine Emperor Romanus II, son and co-regent of Constantine Porphyrogenitos, sent a beautifully illustrated Greek manuscript of De materia medica to the Spanish Khalif, Abd-Arrahman III. In 1250, Syriac scholar Bar Hebraeus prepared an illustrated Syriac version, which was translated into Arabic. | 1 | Applied and Interdisciplinary Chemistry |
On-line Questions are uploaded again after the Summer School. The leftovers of the Summer School and other people who didn't join the Summer School have to take this test to join the Winter School 1. First grade students in the high school take this test. In this test, Organic Chemistry questions will appear more often than the test 1. 25 well-ranked students can join the Winter School 1. | 1 | Applied and Interdisciplinary Chemistry |
Established in 1972, the focus of the research is on cryoinjury, cryosurgery, cryopreservation, lyophilization and hypothermia. Since 1985 the Institute has published the open access peer-reviewed scientific journal Problems of Cryobiology and Cryomedicine. | 1 | Applied and Interdisciplinary Chemistry |
* NDSC observations. The [http://www.ndsc.ncep.noaa.gov/ Network for the Detection for Stratospheric Change] (NDSC) is a set of high-quality remote-sounding research stations for observing and understanding the physical and chemical state of the stratosphere. Ozone and key ozone-related chemical compounds and parameters are targeted for measurement. The NDSC is a major component of the international upper atmosphere research effort and has been endorsed by national and international scientific agencies, including the International Ozone Commission, the United Nations Environment Programme (UNEP), and the World Meteorological Organization (WMO). The primary instruments and measurements are: Ozone lidar (vertical profiles of ozone from the tropopause to at least 40 km altitude; in some cases tropospheric ozone will also be measured). Temperature lidar (vertical profiles of temperature from about 30 to 80 km). Aerosol lidar (vertical profiles of aerosol optical depth in the lower stratosphere). Water vapor lidar (vertical profiles of water vapor in the lower stratosphere). Ozone microwave (vertical profiles of stratospheric ozone from 20 to 70 km). HO microwave (vertical profiles water vapor from about 20 to 80 km). ClO microwave (vertical profiles of ClO from about 25 to 45 km, depending on latitude). Ultraviolet/Visible spectrograph (column abundance of ozone, NO, and, at some latitudes, OClO and BrO). Fourier Transform Infrared spectrometer (column abundances of a broad range of species including ozone, HCl, NO, NO, ClONO, and HNO).
* MkIV observations. The [http://mark4sun.jpl.nasa.gov/ MkIV] Interferometer is a Fourier Transform Infra-Red (FTIR) Spectrometer, designed and built at the Jet Propulsion Laboratory in 1984, to remotely sense the composition of the Earth's atmosphere by the technique of solar absorption spectrometry. This was born out of concern that man-made pollutants (e.g. chlorofluorocarbons, aircraft exhaust) might perturb the ozone layer. Since 1984, the MkIV Interferometer has participated in 3 NASA DC-8 polar aircraft campaigns, and has successfully completed 15 balloon flights. In addition, the MkIV Interferometer made over 900 days of ground-based observations from many different locations, including McMurdo, Antarctica in 1986.
* Sonde observations. The [http://www.woudc.org/index_e.html World Ozone and Ultraviolet Radiation Data Centre] (WOUDC) is one of five World Data Centres which are part of the Global Atmosphere Watch (GAW) programme of the World Meteorological Organization (WMO). The WOUDC is operated by the Experimental Studies Division of the Meteorological Service of Canada (MSC) — formerly Atmospheric Environment Service (AES), Environment Canada and is located in Toronto. The WOUDC began as the World Ozone Data Centre (WODC) in 1960 and produced its first data publication of Ozone Data for the World in 1964. In June 1992, the AES agreed to a request from the WMO to add ultraviolet radiation data to the WODC. The Data Centre has since been renamed to the World Ozone and Ultraviolet Radiation Data Centre (WOUDC) with the two component parts: the WODC and the World Ultraviolet Radiation Data Centre (WUDC). | 1 | Applied and Interdisciplinary Chemistry |
The Algae scrubber is a system designed primarily for cleaning nutrients and pollutants out of water using algal turfs. An algal turf scrubber (ATS) mimics the algal turfs of a natural coral reef by taking in nutrient rich water from waste streams or natural water sources, and pulsing it over a sloped surface. This surface is coated with a rough plastic membrane or a screen, which allows naturally occurring algal spores to settle and colonize the surface. Once the algae has been established, it can be harvested every 5–15 days, and can produce 18 metric tons of algal biomass per hectare per year. In contrast to other methods, which focus primarily on a single high yielding species of algae, this method focuses on naturally occurring polycultures of algae. As such, the lipid content of the algae in an ATS system is usually lower, which makes it more suitable for a fermented fuel product, such as ethanol, methane, or butanol. Conversely, the harvested algae could be treated with a hydrothermal liquefaction process, which would make possible biodiesel, gasoline, and jet fuel production.
There are three major advantages of ATS over other systems. The first advantage is documented higher productivity over open pond systems. The second is lower operating and fuel production costs. The third is the elimination of contamination issues due to the reliance on naturally occurring algae species. The projected costs for energy production in an ATS system are $0.75/kg, compared to a photobioreactor which would cost $3.50/kg. Furthermore, due to the fact that the primary purpose of ATS is removing nutrients and pollutants out of water, and these costs have been shown to be lower than other methods of nutrient removal, this may incentivize the use of this technology for nutrient removal as the primary function, with biofuel production as an added benefit. | 1 | Applied and Interdisciplinary Chemistry |
Solid-state NMR is used to study insoluble proteins and proteins very sensitive to their environment such as membrane proteins and amyloid fibrils. The latter topic relates to protein aggregation diseases such as Alzheimers disease and Parkinsons disease. Solid-state NMR spectroscopy complements solution-state NMR spectroscopy and beam diffraction methods (e.g. X-ray crystallography, electron microscopy). Despite often requiring isotopic enrichment, ssNMR has the advantage that little sample preparation is required and can be used on not just dry or frozen samples, but also fully hydrated samples or native non-crystalline tissues. Solid-state NMR structure elucidation of proteins has traditionally been based on secondary chemical shifts and spatial contacts between nuclei. | 0 | Theoretical and Fundamental Chemistry |
Usually, a set of individually designed oligonucleotides is made on automated solid-phase synthesizers, purified and then connected by specific annealing and standard ligation or polymerase reactions. To improve specificity of oligonucleotide annealing, the synthesis step relies on a set of thermostable DNA ligase and polymerase enzymes. To date, several methods for gene synthesis have been described, such as the ligation of phosphorylated overlapping oligonucleotides, the Fok I method and a modified form of ligase chain reaction for gene synthesis. Additionally, several PCR assembly approaches have been described. They usually employ oligonucleotides of 40-50 nucleotides length that overlap each other. These oligonucleotides are designed to cover most of the sequence of both strands, and the full-length molecule is generated progressively by overlap extension (OE) PCR, thermodynamically balanced inside-out (TBIO) PCR or combined approaches. The most commonly synthesized genes range in size from 600 to 1,200 bp although much longer genes have been made by connecting previously assembled fragments of under 1,000 bp. In this size range it is necessary to test several candidate clones confirming the sequence of the cloned synthetic gene by automated sequencing methods. | 1 | Applied and Interdisciplinary Chemistry |
Gamma ray emission follows the previously discussed modes of decay when the decay leaves a daughter nucleus in an excited state. This nucleus is capable of further de-excitation to a lower energy state by the release of a photon. This decay follows the relation: | 0 | Theoretical and Fundamental Chemistry |
Clinical Biochemistry is a peer-reviewed scientific journal covering the analytical and clinical investigation of laboratory tests in humans used for diagnosis, molecular biology and genetics, prognosis, treatment and therapy, and monitoring of disease ; the discipline of clinical biochemistry. It is the official journal of the Canadian Society of Clinical Chemists. | 1 | Applied and Interdisciplinary Chemistry |
The Thyrotroph Thyroid Hormone Sensitivity Index (abbreviated TTSI, also referred to as Thyrotroph T4 Resistance Index or TT4RI) is a calculated structure parameter of thyroid homeostasis. It was originally developed to deliver a method for fast screening for resistance to thyroid hormone. Today it is also used to get an estimate for the set point of thyroid homeostasis, especially to assess dynamic thyrotropic adaptation of the anterior pituitary gland, including non-thyroidal illnesses. | 1 | Applied and Interdisciplinary Chemistry |
QCD is one part of the modern theory of particle physics called the Standard Model. Other parts of this theory deal with electroweak interactions and neutrinos. The theory of electrodynamics has been tested and found correct to a few parts in a billion. The theory of weak interactions has been tested and found correct to a few parts in a thousand. Perturbative forms of QCD have been tested to a few percent. Perturbative models assume relatively small changes from the ground state, i.e. relatively low temperatures and densities, which simplifies calculations at the cost of generality. In contrast, non-perturbative forms of QCD have barely been tested. The study of the QGP, which has both a high temperature and density, is part of this effort to consolidate the grand theory of particle physics.
The study of the QGP is also a testing ground for finite temperature field theory, a branch of theoretical physics which seeks to understand particle physics under conditions of high temperature. Such studies are important to understand the early evolution of our universe: the first hundred microseconds or so. It is crucial to the physics goals of a new generation of observations of the universe (WMAP and its successors). It is also of relevance to Grand Unification Theories which seek to unify the three fundamental forces of nature (excluding gravity). | 0 | Theoretical and Fundamental Chemistry |
NMOR is a pale yellow sand-like powder below 84°F.
NMOR is most commonly produced from morpholine, but can also be made by the reaction of dimorpholinomethane in fuming nitric acid. Few reactions using NMOR as a starting material are reported in the organic synthesis literature, but it can be used as a precursor to a nitrogen-centered radical. | 0 | Theoretical and Fundamental Chemistry |
Ternary (where there is an alkali or alkaline earth metal, a transition metal as well as tin e.g. LiRhSn and MgRuSn) have been investigated. | 0 | Theoretical and Fundamental Chemistry |
Criticality in nature is uncommon. At three ore deposits at Oklo in Gabon, sixteen sites (the so-called Oklo Fossil Reactors) have been discovered at which self-sustaining nuclear fission took place approximately 2 billion years ago. Unknown until 1972 (but postulated by Paul Kuroda in 1956), when French physicist Francis Perrin discovered the Oklo Fossil Reactors, it was realized that nature had beaten humans to the punch. Large-scale natural uranium fission chain reactions, moderated by normal water, had occurred far in the past and would not be possible now. This ancient process was able to use normal water as a moderator only because 2 billion years before the present, natural uranium was richer in the shorter-lived fissile isotope U (about 3%), than natural uranium available today (which is only 0.7%, and must be enriched to 3% to be usable in light-water reactors). | 0 | Theoretical and Fundamental Chemistry |
The anhydroglucose unit (AGU) refers to a single sugar molecule in a polymer. Each AGU is reduced to its functional groups, 3 hydroxyl groups per AGU.
Carbohydrate AGU:
Cellulose AGU: | 0 | Theoretical and Fundamental Chemistry |
The mass excess of a nuclide is the difference between its actual mass and its mass number in daltons. It is one of the predominant methods for tabulating nuclear mass. The mass of an atomic nucleus is well approximated (less than 0.1% difference for most nuclides) by its mass number, which indicates that most of the mass of a nucleus arises from mass of its constituent protons and neutrons. Thus, the mass excess is an expression of the nuclear binding energy, relative to the binding energy per nucleon of carbon-12 (which defines the dalton). If the mass excess is negative, the nucleus has more binding energy than C, and vice versa. If a nucleus has a large excess of mass compared to a nearby nuclear species, it can radioactively decay, releasing energy. | 0 | Theoretical and Fundamental Chemistry |
* Recovered airlift_basic_calculation.xls via Waybackmachine. Mirrored at filedropper dot com /airliftbasiccalculation.
nl:Gaslift | 1 | Applied and Interdisciplinary Chemistry |
Limans are structures with small dams which catch runoff from a wadi to hold about 400-600mm of water, which suffices for the growth of drought-hardy tree species. Limans can be built wherever tributary wadis [...] widen or come onto a large plain with potential arable land [...]. A check-dam [...] is built to retain runoff waters [...]. A spillway regulates the level of the water [...] to prevent the destruction of the check-dam.. The embankment height should be 3–4 times the designed water depth, and the outlet should be to the side of the main flow to prevent direct through flow. Also, grazers should be excluded from the site to prevent soil compaction which would in turn decrease water infiltration. | 1 | Applied and Interdisciplinary Chemistry |
In gas chromatography, the Kovats retention index (shorter Kovats index, retention index; plural retention indices) is used to convert retention times into system-independent constants. The index is named after the Hungarian-born Swiss chemist Ervin Kováts, who outlined the concept in the 1950s while performing research into the composition of the essential oils.
The retention index of a chemical compound is retention time interpolated between adjacent n-alkanes. While retention times vary with the individual chromatographic system (e.g. with regards to column length, film thickness, diameter and inlet pressure), the derived retention indices are quite independent of these parameters and allow comparing values measured by different analytical laboratories under varying conditions and analysis times from seconds to hours. Tables of retention indices are used to identify peaks by comparing measured retention indices with the tabulated values. | 0 | Theoretical and Fundamental Chemistry |
Methyl orange has mutagenic properties. When methyl orange is put under oxidative stress, one of the double-bonded nitrogen atoms that connects the aromatic rings gets radicalized and can further break down into reactive oxygen species or anilines, which are carcinogenic and can mutate DNA. Various bacteria and enzymes can also cause this breakdown to occur. | 0 | Theoretical and Fundamental Chemistry |
The most common thiolactone, homocysteine thiolactone is produced biochemically from homocysteine and it may play a role in protein damage. The thiolactone functional group is also present in some pharmaceutical drugs such as citiolone and erdosteine. Thiolactone rings can also be found in peptides synthesized by bacteria such as Staphylococcus aureus in order to regulate their quorum-sensing system. | 0 | Theoretical and Fundamental Chemistry |
Cellular respiration is the process by which biological fuels are oxidized in the presence of an inorganic electron acceptor, such as oxygen, to drive the bulk production of adenosine triphosphate (ATP), which contains energy. Cellular respiration may be described as a set of metabolic reactions and processes that take place in the cells of organisms to convert chemical energy from nutrients into ATP, and then release waste products.
Cellular respiration is a vital process that occurs in the cells of all living organisms. Respiration can be either aerobic, requiring oxygen, or anaerobic; some organisms can switch between aerobic and anaerobic respiration.
The reactions involved in respiration are catabolic reactions, which break large molecules into smaller ones, producing large amounts of energy (ATP). Respiration is one of the key ways a cell releases chemical energy to fuel cellular activity. The overall reaction occurs in a series of biochemical steps, some of which are redox reactions. Although cellular respiration is technically a combustion reaction, it is an unusual one because of the slow, controlled release of energy from the series of reactions.
Nutrients that are commonly used by animal and plant cells in respiration include sugar, amino acids and fatty acids, and the most common oxidizing agent is molecular oxygen (O). The chemical energy stored in ATP (the bond of its third phosphate group to the rest of the molecule can be broken allowing more stable products to form, thereby releasing energy for use by the cell) can then be used to drive processes requiring energy, including biosynthesis, locomotion or transportation of molecules across cell membranes. | 1 | Applied and Interdisciplinary Chemistry |
Fecal sludge is defined very broadly as what accumulates in onsite sanitation technologies and specifically is not transported through a sewer. It is composed of human excreta, but also anything else that may go into an onsite containment technology, such as flushwater, cleansing materials and menstrual hygiene products, grey water (i.e. bathing or kitchen water, including fats, oils and grease), and solid waste. Hence, fecal sludge is highly variable, with a very wide range of quantities (i.e. produced and accumulated volumes) and qualities (i.e. characteristics). Fecal sludge is stored onsite, and is periodically collected and transported to a fecal sludge treatment plant, followed by safe disposal or end use. When safely managed, fecal sludge that is collected from pit latrines can also be called "pit latrine sludge", whereas fecal sludge collected from septic tanks can also be called "septic tank sludge" or "septage". | 1 | Applied and Interdisciplinary Chemistry |
Mikhail Tsvet was born on 14 May 1872 in Asti, Italy. His mother was Italian, and his father was a Russian official. His mother died soon after his birth, and he was raised in Geneva, Switzerland. He received his BS degree from the Department of Physics and Mathematics at the University of Geneva in 1893. However, he decided to dedicate himself to botany and received his PhD degree in 1896 for his work on cell physiology. He moved to Saint Petersburg, Russia, in 1896 because his father was recalled from the foreign service. There he started to work at the Biological Laboratory of the Russian Academy of Sciences. His Geneva degrees were not recognized in Russia, and he had to earn Russian degrees. In 1897 he became a teacher of botany courses for women. In 1902 he became a laboratory assistant at the Institute of Plant Physiology of the Warsaw University (now in Poland). In 1903 he became an assistant professor and taught also at other Warsaw universities. After the beginning of World War I, the Warsaw University of Technology was evacuated to Moscow, Russia, and in 1916 again to Gorki near Moscow. In 1917 he became a Professor of Botany and the director of the botanical gardens at the University of Tartu (Yuryev) (now in Estonia). In 1918 when German troops occupied the city, the university was evacuated to Voronezh, a large city in the south of Central Russia. Tsvet died of a chronic inflammation of the throat on 26 June 1919 at the age of 47. | 0 | Theoretical and Fundamental Chemistry |
Aqueous solutions of methanol can decompose into CO hydrogen gas, and water. Although this process is thermodynamically favored, the activation barrier is extremely high, so in practice this reaction is not typically observed. However, electrocatalysts can speed up this reaction greatly, making methanol a possible route to hydrogen storage for fuel cells. Electrocatalysts such as gold, platinum, and various carbon-based materials have been shown to effectively catalyze this process. An electrocatalyst of platinum and rhodium on carbon backed tin-dioxide nanoparticles can break carbon bonds at room temperature with only carbon dioxide as a by-product, so that ethanol can be oxidized into the necessary hydrogen ions and electrons required to create electricity. | 0 | Theoretical and Fundamental Chemistry |
Epoxides react with a broad range of nucleophiles, for example, alcohols, water, amines, thiols, and even halides. With two often nearly equivalent sites of attack, epoxides are examples "ambident substrates." The regioselectivity of ring-opening in asymmetric epoxides generally follows the S2 pattern of attack at the least-substituted carbon, but can be affected by carbocation stability under acidic conditions. This class of reactions is the basis of epoxy glues and the production of glycols. | 0 | Theoretical and Fundamental Chemistry |
Gas networks simulation or gas pipeline simulation is a process of defining the mathematical model of gas transmission and gas distribution systems, which are usually composed of highly integrated pipe networks operating over a wide range of pressures. Simulation allows to predict the behaviour of gas network systems under different conditions. Such predictions can be effectively used to guide decisions regarding the design and operation of the real system. | 1 | Applied and Interdisciplinary Chemistry |
After annihilation any remaining dislocations can align themselves into ordered arrays where their individual contribution to the stored energy is reduced by the overlapping of their strain fields. The simplest case is that of an array of edge dislocations of identical Burgers vector. This idealized case can be produced by bending a single crystal that will deform on a single slip system (the original experiment performed by Cahn in 1949). The edge dislocations will rearrange themselves into tilt boundaries, a simple example of a low-angle grain boundary. Grain boundary theory predicts that an increase in boundary misorientation will increase the energy of the boundary but decrease the energy per dislocation. Thus, there is a driving force to produce fewer, more highly misoriented boundaries. The situation in highly deformed, polycrystalline materials is naturally more complex. Many dislocations of different Burgers vector can interact to form complex 2-D networks. | 1 | Applied and Interdisciplinary Chemistry |
The standard potential of an electrochemical cell requires standard conditions (ΔG°) for all of the reactants. When reactant concentrations differ from standard conditions, the cell potential will deviate from the standard potential. In the 20th century German chemist Walther Nernst proposed a mathematical model to determine the effect of reactant concentration on electrochemical cell potential.
In the late 19th century, Josiah Willard Gibbs had formulated a theory to predict whether a chemical reaction is spontaneous based on the free energy
Here ΔG is change in Gibbs free energy, ΔG° is the cell potential when Q is equal to 1, T is absolute temperature (Kelvin), R is the gas constant and Q is the reaction quotient, which can be calculated by dividing concentrations of products by those of reactants, each raised to the power of its stoichiometric coefficient, using only those products and reactants that are aqueous or gaseous.
Gibbs' key contribution was to formalize the understanding of the effect of reactant concentration on spontaneity.
Based on Gibbs work, Nernst extended the theory to include the contribution from electric potential on charged species. As shown in the previous section, the change in Gibbs free energy for an electrochemical cell can be related to the cell potential. Thus, Gibbs theory becomes
Here n is the number of electrons (in moles), F is the Faraday constant (in coulombs/mole), and ΔE is the cell potential (in volts).
Finally, Nernst divided through by the amount of charge transferred to arrive at a new equation which now bears his name:
Assuming standard conditions (T = 298 K or 25 °C) and R = 8.3145 J/(K·mol), the equation above can be expressed on base-10 logarithm as shown below:
Note that is also known as the thermal voltage V and is found in the study of plasmas and semiconductors as well. The value 0.05916 V in the above equation is just the thermal voltage at standard temperature multiplied by the natural logarithm of 10. | 0 | Theoretical and Fundamental Chemistry |
Quantum dots are fluorescent semiconductor nanoparticles that typically brighter than conventional stains. They are generally more expensive, toxic, do not permeate cell membranes, and cannot be manufactured by the cell. | 1 | Applied and Interdisciplinary Chemistry |
The first zinc(I) dimer was isolated in 2004, with more being synthesized in subsequent years. The chemical similarities between magnesium and zinc led researchers to believe that a Mg(I) dimer could then be achieved. With a calculated stability of Mg—Mg bonded dimers, a synthesis route was needed. | 0 | Theoretical and Fundamental Chemistry |
She went on to earn a BSc in chemistry and mathematics and then a PhD in chemistry at the University of Cape Town. From 1983 to 1986, she pursued post-doctoral studies at Pennsylvania State University. Mizrahi then worked in research and development for pharmaceutical company Smith, Kline & French. In 1989, she established as research unit at the South African Institute for Medical Research and University of the Witwatersrand, remaining there until 2010. Her research has been focused on the treatment of tuberculosis, and drug resistance. In 2011, she became director of the Institute of Infectious Disease and Molecular Medicine at the University of Cape Town. Mizrahi is director of a research unit of the South African Medical Research Council and leads the University of Cape Town branch of the Centre of Excellence in Biomedical TB Research.
Mizrahi received the LOréal-UNESCO Award for Women in Science in 2000. In 2006, she received the Gold Medal from the South African Society for Biochemistry and Molecular Biology for her contributions to the field and the Department of Science and Technologys Distinguished Woman Scientist Award. She is a fellow of the Royal Society of South Africa, a member of the Academy of Science of South Africa and a fellow of the American Academy of Microbiology since 2009. She was named to the Order of Mapungubwe in 2007. From 2000 to 2010, she was an International Research Scholar of the Howard Hughes Medical Institute; in 2012, she was named a Senior International Research Scholar for the Institute until 2017. In 2013, she was awarded the Institut de France's Christophe Mérieux Prize for her work in tuberculosis research. Mizrahi was elected a Fellow of the Royal Society in 2023. | 1 | Applied and Interdisciplinary Chemistry |
Serum creatinine is the most commonly used indicator (but not direct measure) of renal function. Elevated creatinine is not always representative of a true reduction in GFR. A high reading may be due to increased production of creatinine not due to decreased kidney function, to interference with the assay, or to decreased tubular secretion of creatinine. An increase in serum creatinine can be due to increased ingestion of cooked meat (which contains creatinine converted from creatine by the heat from cooking) or excessive intake of protein and creatine supplements, taken to enhance athletic performance. Intense exercise can increase creatinine by increasing muscle breakdown. Dehydration secondary to an inflammatory process with fever may cause a false increase in creatinine concentrations not related to an actual kidney injury, as in some cases with cholecystitis. Several medications and chromogens can interfere with the assay. Creatinine secretion by the tubules can be blocked by some medications, again increasing measured creatinine. | 1 | Applied and Interdisciplinary Chemistry |
There are a number of non-invasive head cooling caps and helmets designed to target cooling at the brain. A hypothermia cap is typically made of a synthetic material such as neoprene, silicone, or polyurethane and filled with a cooling agent such as ice or gel which is either cooled to a very cold temperature, , before application or continuously cooled by an auxiliary control unit. Their most notable uses are in preventing or reducing alopecia in chemotherapy, and for preventing cerebral palsy in babies born with hypoxic ischemic encephalopathy. In the continuously cooled iteration, coolant is cooled with the aid of a compressor and pumped through the cooling cap. Circulation is regulated by means of valves and temperature sensors in the cap. If the temperature deviates or if other errors are detected, an alarm system is activated. The frozen iteration involves continuous application of caps filled with Crylon gel cooled to to the scalp before, during and after intravenous chemotherapy. As the caps warm on the head, multiple cooled caps must be kept on hand and applied every 20 to 30 minutes. | 1 | Applied and Interdisciplinary Chemistry |
Both uncharged transition metal complexes and anionic complexes lead to the required adducts with acidic boranes. On the right is a typical reaction of a Z-ligand where the electron deficit BPh adds to the anionic Fe complex. The presence of Cp and CO ligands further stabilize the Fe-BPh bond. More specific examples include [NEt][CpFe(CO)] which gives the anionic borane iron complex as an amorphous solid from reaction with BPh in diethyl ether. This could even be characterized in solution by a high-field shifted B-NMR signal at −28.8 characteristic of fourfold coordinated boron. | 0 | Theoretical and Fundamental Chemistry |
Adderall is a 3.1:1 mixture of dextro- to levo- amphetamine base equivalent pharmaceutical that contains equal amounts (by weight) of four salts: dextroamphetamine sulfate, amphetamine sulfate, dextroamphetamine saccharate and amphetamine (D,L)-aspartate monohydrate. This result is a 76% dextroamphetamine to 24% levoamphetamine, or to ratio. | 0 | Theoretical and Fundamental Chemistry |
Schwinger variational principle is a variational principle which expresses the scattering T-matrix as a functional depending on two unknown wave functions. The functional attains stationary value equal to actual scattering T-matrix. The functional is stationary if and only if the two functions satisfy the Lippmann-Schwinger equation. The development of the variational formulation of the scattering theory can be traced to works of L. Hultén and J. Schwinger in 1940s. | 0 | Theoretical and Fundamental Chemistry |
The most common chemicals used for DNA extraction include:
# Detergents, such as SDS or Tween-20, which are used to break open cells and release the DNA.
# Protease enzymes, such as Proteinase K, which are used to digest proteins that may be binding to the DNA.
# Phenol and chloroform, which are used to separate the DNA from other cellular components.
# Ethanol or isopropanol, which are used to precipitate the DNA.
# Salt, such as NaCl, which is often used to help dissolve the DNA and maintain its stability.
# EDTA, which is used to chelate the metals ions that can damage the DNA.
# Tris-HCL, which is used to maintain the pH at the optimal condition for DNA extraction. | 1 | Applied and Interdisciplinary Chemistry |
A reversible solid oxide cell (rSOC) is a solid-state electrochemical device that is operated alternatively as a solid oxide fuel cell (SOFC) and a solid oxide electrolysis cell (SOEC). Similarly to SOFCs, rSOCs are made of a dense electrolyte sandwiched between two porous electrodes. Their operating temperature ranges from 600°C to 900°C, hence they benefit from enhanced kinetics of the reactions and increased efficiency with respect to low-temperature electrochemical technologies.
When utilized as a fuel cell, the reversible solid oxide cell is capable of oxidizing one or more gaseous fuels to produce electricity and heat. When used as an electrolysis cell, the same device can consume electricity and heat to convert back the products of the oxidation reaction into valuable fuels. These gaseous fuels can be pressurized and stored for a later use. For this reason, rSOCs are recently receiving increased attention due to their potential as an energy storage solution on the seasonal scale. | 0 | Theoretical and Fundamental Chemistry |
Doxorubicin is a very effective anti-cancer drug that causes congestive heart failure while treating tumors. Doxorubicin is an uncoupling agent in that it inhibits proper functioning of complex I of the electron transport chain in mitochondria. It then leads to the production of ROS and the inhibition of ATP production. Doxorubicin has been shown to be selectively toxic to cardiac tissue, although some toxicity has been seen in other tissues as well. Other anti-cancer drugs, such as fluoropyrimidines and taxanes, are extremely effective at treating and reducing tumor proliferation, but have high incidences of cardiac arrhythmias and myocardial infarctions. | 1 | Applied and Interdisciplinary Chemistry |
Flow injection analysis (FIA) was first described by Ruzicka and Hansen in Denmark and Stewart and coworkers in United States in the middle of 1970. FIA is a popular, simple, rapid, and versatile technique which is a well-established position in modern analytical chemistry, and widespread application in quantitative chemical analysis. | 0 | Theoretical and Fundamental Chemistry |
The most important series of symposia are the International Symposia on Chemical Reaction Engineering or [http://www.iscre.org/ ISCRE conferences]. These three-day conferences are held every two years, rotating among sites in North America, Europe, and the Asia-Pacific region, on a six-year cycle. These conferences bring together for three days distinguished international researchers in reaction engineering, prominent industrial practitioners, and new researchers and students of this multifaceted field. ISCRE symposia are a unique gathering place for reaction engineers where research gains are consolidated and new frontiers explored. The state of the art of various sub-disciplines of reaction engineering is reviewed in a timely manner, and new research initiatives are discussed. | 1 | Applied and Interdisciplinary Chemistry |
The European Medicines Agency (EMA) has concluded that the extract of the natural product Saw palmetto can be used to treat symptoms of benign prostatic hyperplasia (BPH) as research has shown its 5-ARI effects. An extract of Serenoa repens, also known as saw palmetto extract, is a 5-ARI that is sold as an over-the-counter dietary supplement. It is also used under the brand name Permixon in Europe as a pharmaceutical drug for the treatment of benign prostatic hyperplasia. | 1 | Applied and Interdisciplinary Chemistry |
Polypeptides, the precursors of proteins, are chains of amino acids. The two ends of a polypeptide are called the N-terminus, or amino end, and the C-terminus, or carboxyl end. For many (but not all) chloroplast proteins encoded by nuclear genes, cleavable transit peptides are added to the N-termini of the polypeptides, which are used to help direct the polypeptide to the chloroplast for import (N-terminal transit peptides are also used to direct polypeptides to plant mitochondria).
N-terminal transit sequences are also called presequences because they are located at the "front" end of a polypeptide—ribosomes synthesize polypeptides from the N-terminus to the C-terminus.
Chloroplast transit peptides exhibit huge variation in length and amino acid sequence. They can be from 20 to 150 amino acids long—an unusually long length, suggesting that transit peptides are actually collections of domains with different functions. Transit peptides tend to be positively charged, rich in hydroxylated amino acids such as serine, threonine, and proline, and poor in acidic amino acids like aspartic acid and glutamic acid. In an aqueous solution, the transit sequence forms a random coil.
Not all chloroplast proteins include a N-terminal cleavable transit peptide though. Some include the transit sequence within the functional part of the protein itself. A few have their transit sequence appended to their C-terminus instead. Most of the polypeptides that lack N-terminal targeting sequences are the ones that are sent to the outer chloroplast membrane, plus at least one sent to the inner chloroplast membrane. | 0 | Theoretical and Fundamental Chemistry |
Kode FSL constructs consist of three components; a functional moiety (F), a spacer (S) and a lipid (L).
Function groups on FSL constructs that can be used to create kodecytes include saccharides (including ABO blood group-related determinants, sialic acids, hyaluronin polysaccharides), fluorophores, biotin, and a range of peptides.
Although kodecytes are created by modifying natural cells, they are different from natural cells. For example, FSL constructs, influenced by the composition of the lipid tail, are laterally mobile in the membrane and some FSL constructs may also cluster due to the characteristics of the functional group (F). As FSL constructs are anchored in the membrane via a lipid tail (L) it is believed they do not participate in signal transduction, but may be designed to act as agonists or antagonists of the initial binding event. FSL constructs will not actively pass through the plasma membrane but may enter the cell via membrane invagination and endocytosis.
The "koding" of cells is stable (subject to the rate of turnover of the membrane components). FSL constructs will remain in the membrane of inactive cells (e.g. red blood cells) for the life of the cell provided it is stored in lipid free media. In the peripheral circulation FSL constructs are observed to be lost from red cell kodecytes at a rate of about 1% per hour. The initial "koding" dose and the minimum level required for detection determine how long the presence of "kodecytes" in the circulation can be monitored. For red blood "kodecytes" reliable monitoring of the presence of the "kodecytes" for up to 3 days post intravenous administration has been demonstrated in small mammals.
The spacer (S) of a FSL construct has been selected so as to have negligible cross-reactivity with serum antibodies so kodecytes can be used with undiluted serum. By increasing the length of the FSL spacer from 1.9 to 7.2 nm it has been shown sensitivity can improve two-fold in red cell agglutination based kodecyte assays. However, increasing the size of the spacer further from 7.2 to 11.5 nm did not result in any further enhancement. | 1 | Applied and Interdisciplinary Chemistry |
In cell biology, microtubule-associated proteins (MAPs) are proteins that interact with the microtubules of the cellular cytoskeleton. MAPs are integral to the stability of the cell and its internal structures and the transport of components within the cell. | 1 | Applied and Interdisciplinary Chemistry |
He was born in Kristiania (now Oslo), Norway. He was a son of colonel Lars Jørgen Tysland (1848–1911) and Marie Cathrine Sandberg (1862–1942). He was a maternal grandson of military officer Ole Rømer Sandberg (1831–1899) and cousin of legislator Ole Rømer Aagaard Sandberg (1900–1985).
He grew up in Kristiania and Bergen, and graduated from Bergen tekniske skole in 1908 before finishing his secondary education at Bergen Cathedral School in 1910. He graduated from the University of Liège in Belgium during 1913.
He was a manager at Tinfos Jernverk in Notodden from 1913 to 1916, and then spent half a year in the United States, a stay interrupted by rheumatic fever. Back in Norway he established Skaland Grafittverk in Senja during 1918, was hired in the Ministry of Trade in 1921 and then in Fiskaa Verk in Kristiansand during 1922.
He was next hired to experiment with new electric smelting furnaces. The Tysland-Hole Furnace (Tysland-Hole-ovnen) was first erected at Christiania Spigerverk in 1928 and was put on use in 1929. The Tysland-Hole furnace was developed by Tysland jointly with engineer Ivar Hole (1882–1939). Railway rails and reinforcing steel become main products produced.
Tysland worked at Christiania Spigerverk from 1924 to 1927, Bremanger Smelteverk in Svelgen from 1927 to 1931, then Skaland Grafittverk in Skaland from 1931 to his death from heart failure. | 1 | Applied and Interdisciplinary Chemistry |
In organic chemistry, carboboration describes an addition of both a carbon and a boron moiety to certain carbon-containing double and triple bonds, such as alkenes, alkynes, and allenes.
In the synthesis of organic compounds, this chemical reaction is used to install a new carbon-carbon bond and carbon-boron bond. The product of carboboration reactions are organoborane compounds which prove to be useful in organic synthesis, containing both a new carbon group and a boron handle for further functionalization. This carbon-boron bond allows for organoboron chemistry, which facilitates a wide variety of chemical transformations such as oxidation and the Suzuki Reaction. The carbon-boron bond can be transformed into a variety of functional groups and moieties, making it highly useful in pharmaceutical chemistry and organic synthesis.
Carboboration was developed soon after the advent and widespread use of hydroboration. Carboboration is often facilitated via catalysis, often employing transition metals, and usually involves an activated alkene or alkyne. The two most well-documented categories of carboboration are 1,1 and 1,2 carboboration, which differ in the regioselectivity of the incoming carbon group. | 0 | Theoretical and Fundamental Chemistry |
In the field of statistics, the Neyman–Pearson lemma states that the most powerful way to distinguish between the two distributions and based on an observation (drawn from one of them) is through the log of the ratio of their likelihoods: . The KL divergence is the expected value of this statistic if is actually drawn from . Kullback motivated the statistic as an expected log likelihood ratio. | 0 | Theoretical and Fundamental Chemistry |
plants have a competitive advantage over plants possessing the more common carbon fixation pathway under conditions of drought, high temperatures, and nitrogen or limitation. When grown in the same environment, at 30 °C, grasses lose approximately 833 molecules of water per molecule that is fixed, whereas grasses lose only 277. This increased water use efficiency of grasses means that soil moisture is conserved, allowing them to grow for longer in arid environments.
carbon fixation has evolved in at least 62 independent occasions in 19 different families of plants, making it a prime example of convergent evolution. This convergence may have been facilitated by the fact that many potential evolutionary pathways to a phenotype exist, many of which involve initial evolutionary steps not directly related to photosynthesis. plants arose around during the Oligocene (precisely when is difficult to determine) and were becoming ecologically significant in the early Miocene around . metabolism in grasses originated when their habitat migrated from the shady forest undercanopy to more open environments, where the high sunlight gave it an advantage over the pathway. Drought was not necessary for its innovation; rather, the increased parsimony in water use was a byproduct of the pathway and allowed plants to more readily colonize arid environments.
Today, plants represent about 5% of Earth's plant biomass and 3% of its known plant species. Despite this scarcity, they account for about 23% of terrestrial carbon fixation. Increasing the proportion of plants on earth could assist biosequestration of and represent an important climate change avoidance strategy. Present-day plants are concentrated in the tropics and subtropics (below latitudes of 45 degrees) where the high air temperature increases rates of photorespiration in plants. | 0 | Theoretical and Fundamental Chemistry |
Compared to the number of drug candidates that have successfully made it to the clinical trial phase, there are many more lead compounds which have been tested in vivo using various animal models. Much of the current work that has progressed to in vivo testing has been directed to the RNA repeat expansions implicated in genetic neuromuscular diseases. In myotonic dystrophy type 1 (DM1), r(CUG)exp mRNAs sequester proteins including the alternative splicing regulator MBNL1 into the nucleus causing missplicing. Several groups have developed compounds which bind the toxic RNA and dissolve nuclear foci. In 2011, Artero and coworkers discovered that a peptide could reduce the toxicity associated with r(CUG) repeats in Drosophila and mouse models. [https://scholar.google.com/citations?user=sYLAwlMAAAAJ&hl=en Disney] and colleagues provided the first small molecules that targeted r(CUG) repeats in animals models by using rational designing to identify many small molecules directly targeting this toxic RNA and the compounds improved disease defects in a DM1 mouse model.
Other works by the Disney group has shown that in cellular models of various RNA-mediated diseases that are causes by RNA repeats such as r(CAG) in Huntingtons disease and r(CCUG) repeats in Myotonic Dystrophy Types 2 could also be targeted with small molecules. Nakamori and colleagues also reported in 2012 that erythromycin could be orally dosed in DM1 mouse models to restore missplicing defects and inhibit the complex formed between r(CUG) and MBNL1. In that same year, Miller and coworkers screened a library of compounds to find a small molecule drug that could improve splicing defects in a mouse model. The Zimmerman group has taken a rational design approach to discovering small molecule drugs that target r(CUG). One such compound contains a selective triaminotriazine recognition motif which binds to the UU mismatches in r(CUG) selectively most likely in a base triplet combined with an amidinium RNA groove binding unit. Studies using a Drosophila' model for DM1 showed an influence on related phenotypic outcomes such as eye morphology and climbing distance.
Aside from studies involved r(CUG) repeats, other complex RNA structures have also been targeted. Pearson and coworkers discovered that a cationic porphyrin (TMPyP4) bound a G-quadruplex r(GC) and inhibited the binding of proteins to r(GC). Work by Disney and Petrucelli rationally identified small molecules that can target this repeat and affect disease biology in model cellular systems and also in patient-derive iNeurons. Further studies by Rothstein and colleagues determined that TMPyP4 could suppress r(GC)-mediated neurodegeneration in a Drosophila model. Additionally targets have been rationally identified by using a powerful seqecune-based design approach termed informal to identify dozens of bioactive small molecules that target disease causing non-coding RNA termed INFORNA. This study important showed for the first time that small molecules appear to have selectivities that are competitive with oligonucleotides with cell-permeable and medicinally optimizable small molecules. Additionally, compounds have been shown to be bioactive in diverse disease settings that ranged from breast cancer. and hepatocellular carcinoma. More recently, the Disney group further used their prediction database INFORNA to design Targaprimir-96 to target miRNA precursors in animal models of cancer, the first small molecules to do so. This compound has a nanomolar affinity for the miRNA hairpin precursor selectively over other sequences. Targaprimir-96 was further tested in cells and in mice, inhibiting tumor growth in a xenograft mouse model of triple negative breast cancer upon i.p. injection. | 1 | Applied and Interdisciplinary Chemistry |
Side effects of dextromethorphan at normal therapeutic doses can include:
A rare side effect is respiratory depression. | 0 | Theoretical and Fundamental Chemistry |
Alexander Anim-Mensah, also known as Alexander Raymond Anim-Mensah, is a Ghanaian-American chemical engineer, inventor, and author. He is especially known for contributions he made towards the field of membrane science and technology. He is a recipient of the Illinois Tool Works' Distinguished Patent Fellow Award. | 1 | Applied and Interdisciplinary Chemistry |
Phosphodiesterase enzymes have been shown to be different in different types of cells, including normal and leukemic lymphocytes and are often targets for pharmacological inhibition due to their unique tissue distribution, structural properties, and functional properties.
Inhibitors of PDE can prolong or enhance the effects of physiological processes mediated by cAMP or cGMP by inhibition of their degradation by PDE.
Sildenafil (Viagra) is an inhibitor of cGMP-specific phosphodiesterase type 5, which enhances the vasodilatory effects of cGMP in the corpus cavernosum and is used to treat erectile dysfunction. Sildenafil is also currently being investigated for its myo- and cardioprotective effects, with particular interest being given to the compound's therapeutic value in the treatment of Duchenne muscular dystrophy and benign prostatic hyperplasia.
Paraxanthine, the main metabolite of caffeine, is another cGMP-specific phosphodiesterase inhibitor which inhibits PDE9, a cGMP preferring phosphodiesterase. PDE9 is expressed as high as PDE5 in the corpus cavernosum. | 1 | Applied and Interdisciplinary Chemistry |
Instead of collision-based kinetic description for interaction of charged particles in plasma, Vlasov utilizes a self-consistent collective field created by the charged plasma particles. Such a description uses distribution functions and for electrons and (positive) plasma ions. The distribution function for species describes the number of particles of the species having approximately the momentum near the position at time . Instead of the Boltzmann equation, the following system of equations was proposed for description of charged components of plasma (electrons and positive ions):
Here is the elementary charge (), is the speed of light, is the mass of the ion, and represent collective self-consistent electromagnetic field created in the point at time moment by all plasma particles. The essential difference of this system of equations from equations for particles in an external electromagnetic field is that the self-consistent electromagnetic field depends in a complex way on the distribution functions of electrons and ions and . | 1 | Applied and Interdisciplinary Chemistry |
Desnitro-imidacloprid is a metabolite of the insecticide imidacloprid, a very common insecticide and the most important member of the class of insecticides called neonicotinoids, the only significant new class of insecticides to be developed between 1970 and 2000. While imidacloprid has proved highly selective against insects, the desnitro- version is highly toxic to mammals, due to its agonist action at the alpha4beta2 nicotinic acetylcholine receptor (nAChR) in the mammalian brain, at least as demonstrated in experiments involving mice. | 1 | Applied and Interdisciplinary Chemistry |
The common structure for analogs that inhibit TNF-α via inhibition of PDE4 is prepared on the basis of hydrolysing the glutarimide ring of thalidomide. These analogs do not have an acidic chiral hydrogen, unlike thalidomide, and would therefore be expected to be chirally stable.
On the phenyl ring, a 3,4-dialkoxyphenyl moiety (Figure 6) is a known pharmacophore in PDE4 inhibitors such as rolipram. Optimal activity is achieved with a methoxy group at the 4-position (X2) and a bigger group, such as cyclopentoxy at the 3-position carbon (X3). However the thalidomide PDE4 inhibitory analogs do not follow the SAR of rolipram analogs directly. For thalidomide analogs, an ethoxy group at X3 and a methoxy group at X2, with X1 being just a hydrogen, gave the highest PDE4 and TNF-α inhibition. Substitutes larger than diethoxy at the X2–X3 position had decreased activity. The effects of these substitutions seem to be mediated by steric effects.
For the Y-position, a number of groups have been explored. Substituted amides that were larger than methylamide (CONHCH) decrease PDE4 inhibition activity. Using a carboxylic acid as a starting point, an amide group has similar PDE4 inhibition activity but both groups were shown to be a considerably less potent than a methyl ester group, which had about six-fold increase in PDE4 inhibitory activity. Sulfone group had similar PDE4 inhibition as the methyl ester group. The best PDE4 inhibition was observed when a nitrile group was attached, which has 32 times more PDE4 inhibitory activity than the carboxyl acid. Substituents at Y leading to increasing PDE4 inhibitory activity thus followed the order:
: COOH ≤ CONH ≤ COOCH ≤ SOCH < CN
Substitutions on the phthaloyl ring have been explored and it was noticed that nitro groups at the C4 or C5 location decreased activity but C4 or C5 amino substitution increased it dramatically. When the substitution at the 4 (Z) location on the phthaloyl ring was examined, hydroxyl and methoxy groups seem to make the analog a less potent PDE4 inhibitor. An increase in activity was observed with amino and dimethylamino to a similar extent but a methyl group improved the activity further than the aforementioned groups. A 4-N-acetylamino group had slightly lower PDE4 inhibitory activity, compared with the methyl group, but increased the compound's TNF-α inhibitory activity to a further extent. Substituents at Z leading to increasing PDE4 inhibitory activity thus followed the order:
: N(CH) ≤ NH | 1 | Applied and Interdisciplinary Chemistry |
Cilazapril is an angiotensin-converting enzyme inhibitor (ACE inhibitor) used for the treatment of hypertension and congestive heart failure.
It was patented in 1982 and approved for medical use in 1990. | 0 | Theoretical and Fundamental Chemistry |
The initial product of copper smelting was impure black copper, which was then repeatedly melted to purify it, alternately oxidizing and reducing it. In one of the melting stages, lead was added. Gold and silver preferentially dissolved in this, thus providing a means of recovering these precious metals. To produce purer copper suitable for making copper plates or hollow-ware, further melting processes were undertaken, using charcoal as fuel. The repeated application of such fire-refining processes was capable of producing copper that was 99.25% pure. | 1 | Applied and Interdisciplinary Chemistry |
The members of the order Pasteurellales are currently distinguished mainly based on their position in the branching of the 16srRNA tree. There are currently very few molecular markers known that can distinguish members of this order from other bacteria. A CSI approach was recently used to elucidate the phylogenetic relationships between the species in this order; more than 40 CSIs were discovered that were uniquely shared by all or most of the species. Two major clades are formed within this Pasteurellales: Clade I, encompassing Aggregatibacter, Pasteurella, Actinobacillus succinogenes, Mannheimia succiniciproducens, Haemophilus influenzae and Haemophilus somnus, was supported by 13 CSIs. Clade II, encompassing Actinobacillus pleuropneumoniae, Actinobacillus minor, Haemophilus ducreyi, Mannheimia haemolytica and Haemophilus parasuis, was supported by 9 CSIs. Based on these results, it was proposed that Pasteurellales be divided from its current one family into two different ones. Additionally, the signatures described would provide novel means of identifying undiscovered Pasteurellales species. | 1 | Applied and Interdisciplinary Chemistry |
Eutrophication can be a natural process and occurs naturally through the gradual accumulation of sediment and nutrients. Naturally, eutrophication is usually caused by the natural accumulation of nutrients from dissolved phosphate minerals and dead plant matter in water.
Natural eutrophication has been well-characterized in lakes. Paleolimnologists now recognise that climate change, geology, and other external influences are also critical in regulating the natural productivity of lakes. A few artificial lakes also demonstrate the reverse process (meiotrophication), becoming less nutrient rich with time as nutrient poor inputs slowly elute the nutrient richer water mass of the lake. This process may be seen in artificial lakes and reservoirs which tend to be highly eutrophic on first filling but may become more oligotrophic with time. The main difference between natural and anthropogenic eutrophication is that the natural process is very slow, occurring on geological time scales. | 1 | Applied and Interdisciplinary Chemistry |
PIK3CA frequently have gain of function mutations in urothelial cancer. Similar to PI3Ka, PI3Kb is expressed in many different cells, and it is mainly involved in the activation of platelets and development of thrombotic diseases. Studies have shown that PI3Kb contribute to tumor proliferation as well. Specifically, it has an important role in tumorigenesis in PTEN-negative cancers. It's reported that interfering with the gene for PI3Kb might be a therapeutic approach for high-risk bladder cancers with mutant PTEN and E-cadherin loss. Specific isoform inhibitors to PI3Kb is a potential treatment for PTEN-deficient cancers. | 1 | Applied and Interdisciplinary Chemistry |
Amine oxidation with benzoyl peroxide is the most common method to synthesize hydroxylamines. Care must be taken to prevent over-oxidation to a nitrone. Other methods include:
* Hydrogenation of an oxime
* Alkylating a precursor hydroxylamine
* Amine oxide pyrolysis (the Cope reaction) | 0 | Theoretical and Fundamental Chemistry |
The amount of electric charge (quantity of electricity) passed through the cell can easily be determined by measuring the change in mass of either electrode and calculating:
where:
* is the quantity of electricity (coulombs)
* is the mass transported (gm)
* is the charge of the copper ions, equal to +2
* is the Faraday constant (96485.3383 coulombs per mole)
* is the atomic weight of copper, equal to 63.546 grams per mole.
Although this apparatus is interesting from a theoretical and historical point of view, present-day electronic measurement of time and electric current provide in their multiplication the amount of passed coulombs much easier, with greater precision, and in a shorter period of time than is possible by weighing the electrodes. | 0 | Theoretical and Fundamental Chemistry |
Since small amounts of radionuclides are typically being analyzed, the mechanics of manipulating tiny quantities is challenging. This problem is classically addressed by the use of carrier ions. Thus, carrier addition involves the addition of a known mass of stable ion to radionuclide-containing sample solution. The carrier is of the identical element but is non-radioactive. The carrier and the radionuclide of interest have identical chemical properties. Typically the amount of carrier added is conventionally selected for the ease of weighing such that the accuracy of the resultant weight is within 1%. For alpha particles, special techniques must be applied to obtain the required thin sample sources. The use of carries was heavily used by Marie Curie and was employed in the first demonstration of nuclear fission.
Isotope dilution is the reverse of tracer addition. It involves the addition of a known (small) amount of radionuclide to the sample that contains a known stable element. This additive is the "tracer." It is added at the start of the analysis procedure. After the final measurements are recorded, sample loss can be determined quantitatively. This procedure avoids the need for any quantitative recovery, greatly simplifying the analytical process. | 0 | Theoretical and Fundamental Chemistry |
Also known as ionotropic receptors, this group of channels open in response to specific ligand molecules binding to the extracellular domain of the receptor protein. Ligand binding causes a conformational change in the structure of the channel protein that ultimately leads to the opening of the channel gate and subsequent ion flux across the plasma membrane. Examples of such channels include the cation-permeable nicotinic acetylcholine receptors, ionotropic glutamate-gated receptors, acid sensing ion channels (ASICs), ATP-gated P2X receptors, and the anion-permeable γ-aminobutyric acid-gated GABA receptor.
Ion channels activated by second messengers may also be categorized in this group, although ligands and second messengers are otherwise distinguished from each other. | 1 | Applied and Interdisciplinary Chemistry |
When a viral gene is introduced into the host cell and is sufficient to induce oncogenesis – the creation of cancerous cells – in the infected cell line, the gene is said to be a "viral transforming gene". When this type of gene is translated to a protein, the protein is called a "transforming protein". Note that since the viral oncogenes originated from a host genome, the transformation event is different from transduction, which describes the process of introducing non-native genes to a host organism via a viral infection. | 1 | Applied and Interdisciplinary Chemistry |
4-Pyrrolidinylpyridine is an organic compound with the formula (CH)NCHN. The molecule consists of a pyrrodinyl group ((CH)N-) attached via N to the 4-position of pyridine. It is a white solid. The compound has attracted interest because it (pK = 9.58) is more basic than dimethylaminopyridine (pK = 9.41). It is a popular base catalyst. | 0 | Theoretical and Fundamental Chemistry |
The economic nature of many products manufactured in batch and continuous processes require highly efficient operation due to thin margins. The competing factor in process control is that products must meet certain specifications in order to be satisfactory. These specifications can come in two forms: a minimum and maximum for a property of the material or product, or a range within which the property must be. All loops are susceptible to disturbances and therefore a buffer must be used on process set points to ensure disturbances do not cause the material or product to go out of specifications. This buffer comes at an economic cost (i.e. additional processing, maintaining elevated or depressed process conditions, etc.).
Process efficiency can be enhanced by reducing the margins necessary to ensure product specifications are met. This can be done by improving the control of the process to minimize the effect of disturbances on the process. The efficiency is improved in a two step method of narrowing the variance and shifting the target. Margins can be narrowed through various process upgrades (i.e. equipment upgrades, enhanced control methods, etc.). Once margins are narrowed, an economic analysis can be done on the process to determine how the set point target is to be shifted. Less conservative process set points lead to increased economic efficiency. Effective process control strategies increase the competitive advantage of manufacturers who employ them. | 1 | Applied and Interdisciplinary Chemistry |
Antioxidants play a crucial role in mitigating lipid peroxidation by neutralizing free radicals, thereby halting radical chain reactions. Key antioxidants include vitamin C and vitamin E. Additionally, enzymes including superoxide dismutase, catalase, and peroxidase contribute to the oxidation response by reducing the presence of hydrogen peroxide, which is a prevalent precursor of the hydroxyl radical ().
As an example, vitamin E can donate a hydrogen atom to the lipid hydroperoxyl radical () to form a vitamin E radical, which further reacts with another lipid hydroperoxyl radical () forming non-radical products. | 1 | Applied and Interdisciplinary Chemistry |
PG cooling is typically performed using a 3D optical setup with three pairs of perpendicular laser beams with an atomic ensemble in the center. Each beam is prepared with an orthogonal polarization to its counterpropagating beam. The laser frequency detuned from a selected transition between the ground and excited states of the atom. Since the cooling processes rely on multiple transitions between care must be taken such that the atomic does not fall out of these two states. This is done by using a second, "repumping", laser to pump any atoms that fall out back into the ground state of the transition. For example: in cesium cooling experiments, the cooling laser is typically chosen to be detuned from the to transition and a repumping laser tuned to the to transition is also used to prevent the Cs atoms from being pumped into the state.
The atoms must be cooled before the PG cooling, this can be done using the same setup via Doppler cooling. If the atoms are precooled with Doppler cooling, the laser intensity must be lowered and the detuning increased for PG cooling to be achieved.
The atomic temperature can be measured using the time of flight (ToF) technique. In this technique, the laser beams are suddenly turned off and the atomic ensemble is allowed to expand. After a set time delay t, a probe beam is turned on to image the ensemble and obtain the spatial extent of the ensemble at time t. By imaging the ensemble at several time delays, the rate of expansion is found. By measuring the rate of expansion of the ensemble the velocity distribution is measured and from this, the temperature is inferred.
An important theoretical result is that in the regime where PG cooling functions, the temperature only depends on the ratio of to and that the cooling approaches the recoil limit. These predictions were confirmed experimentally in 1990 when W.D. Phillips et al. observed such scaling in their cesium atoms as well as a temperature of 2.5K, 12 times the recoil temperature of 0.198K for the D2 line of cesium used in the experiment. | 0 | Theoretical and Fundamental Chemistry |
Hill's spherical vortex is an exact solution of the Euler equations that is commonly used to model a vortex ring. The solution is also used to model the velocity distribution inside a spherical drop of one fluid moving at a constant velocity through another fluid at small Reynolds number. The vortex is named after Micaiah John Muller Hill who discovered the exact solution in 1894. The two-dimensional analogue of this vortex is the Lamb–Chaplygin dipole.
The solution is described in the spherical polar coordinates system with corresponding velocity components . The velocity components are identified from Stokes stream function as follows
The Hill's spherical vortex is described by
where is a constant freestream velocity far away from the origin and is the radius of the sphere within which the vorticity is non-zero. For , the vorticity is zero and the solution described above in that range is nothing but the potential flow past a sphere of radius . The only non-zero vorticity component for is the azimuthal component that is given by
Note that here the parameters and can be scaled out by non-dimensionalization. | 1 | Applied and Interdisciplinary Chemistry |
Ultraviolet in sewage treatment is commonly replacing chlorination. This is in large part because of concerns that reaction of the chlorine with organic compounds in the waste water stream could synthesize potentially toxic and long lasting chlorinated organics and also because of the environmental risks of storing chlorine gas or chlorine containing chemicals. Individual wastestreams to be treated by UVGI must be tested to ensure that the method will be effective due to potential interferences such as suspended solids, dyes, or other substances that may block or absorb the UV radiation. According to the World Health Organization, "UV units to treat small batches (1 to several liters) or low flows (1 to several liters per minute) of water at the community level are estimated to have costs of US$20 per megaliter, including the cost of electricity and consumables and the annualized capital cost of the unit."
Large-scale urban UV wastewater treatment is performed in cities such as Edmonton, Alberta. The use of ultraviolet light has now become standard practice in most municipal wastewater treatment processes. Effluent is now starting to be recognized as a valuable resource, not a problem that needs to be dumped. Many wastewater facilities are being renamed as water reclamation facilities, whether the wastewater is discharged into a river, used to irrigate crops, or injected into an aquifer for later recovery. Ultraviolet light is now being used to ensure water is free from harmful organisms. | 0 | Theoretical and Fundamental Chemistry |
Water vapor is lighter or less dense than dry air. At equivalent temperatures it is buoyant with respect to dry air, whereby the density of dry air at standard temperature and pressure (273.15 K, 101.325 kPa) is 1.27 g/L and water vapor at standard temperature has a vapor pressure of 0.6 kPa and the much lower density of 0.0048 g/L. | 1 | Applied and Interdisciplinary Chemistry |
Macromolecular crowding is an important effect in biochemistry and cell biology. For example, the increase in the strength of interactions between proteins and DNA produced by crowding may be of key importance in processes such as transcription and DNA replication. Crowding has also been suggested to be involved in processes as diverse as the aggregation of hemoglobin in sickle-cell disease, and the responses of cells to changes in their volume.
The importance of crowding in protein folding is of particular interest in biophysics. Here, the crowding effect can accelerate the folding process, since a compact folded protein will occupy less volume than an unfolded protein chain. However, crowding can reduce the yield of correctly folded protein by increasing protein aggregation. Crowding may also increase the effectiveness of chaperone proteins such as GroEL in the cell, which could counteract this reduction in folding efficiency. It has also been shown that macromolecular crowding affects protein-folding dynamics as well as overall protein shape where distinct conformational changes are accompanied by secondary structure alterations implying that crowding-induced shape changes may be important for protein function and malfunction in vivo.
A particularly striking example of the importance of crowding effects involves the crystallins that fill the interior of the lens. These proteins have to remain stable and in solution for the lens to be transparent; precipitation or aggregation of crystallins causes cataracts. Crystallins are present in the lens at extremely high concentrations, over 500 mg/ml, and at these levels crowding effects are very strong. The large crowding effect adds to the thermal stability of the crystallins, increasing their resistance to denaturation. This effect may partly explain the extraordinary resistance shown by the lens to damage caused by high temperatures.
Crowding may also play a role in diseases that involve protein aggregation, such as sickle cell anemia where mutant hemoglobin forms aggregates and alzheimer's disease, where tau protein forms neurofibrillary tangles under crowded conditions within neurons. | 0 | Theoretical and Fundamental Chemistry |
A French drain (also called a weeping tile, trench drain, filter drain, blind drain, rubble drain, rock drain, drain tile, perimeter drain, land drain, French ditch, sub-surface drain, sub-soil drain, or agricultural drain) is a trench filled with gravel or rock, or both, with or without a perforated pipe that redirects surface water and groundwater away from an area. The perforated pipe is called a weeping tile (also called a drain tile or perimeter tile). When the pipe is draining, it "weeps", or exudes liquids. It was named during a time period when drainpipes were made from terracotta tiles.
French drains are primarily used to prevent ground and surface water from penetrating or damaging building foundations and as an alternative to open ditches or storm sewers for streets and highways. Alternatively, French drains may be used to distribute water, such as a septic drain field at the outlet of a typical septic tank sewage treatment system. French drains are also used behind retaining walls to relieve ground water pressure. | 1 | Applied and Interdisciplinary Chemistry |
Gamma TiAl has excellent mechanical properties and oxidation and corrosion resistance at elevated temperatures (over 600°C), which makes it a possible replacement for traditional Ni based superalloy components in aircraft turbine engines.
TiAl-based alloys have potential to increase the thrust-to-weight ratio in aircraft engines. This is especially the case with the engine's low-pressure turbine blades and the high-pressure compressor blades. These are traditionally made of Ni-based superalloy, which is nearly twice as dense as TiAl-based alloys. Some gamma titanium aluminide alloys retain strength and oxidation resistance to 1000 °C, which is 400 °C higher than the operating temperature limit of conventional titanium alloys.
General Electric uses gamma TiAl for the low-pressure turbine blades on its GEnx engine, which powers the Boeing 787 and Boeing 747-8 aircraft. This was the first large-scale use of this material on a commercial jet engine when it entered service in 2011. The TiAl LPT blades are cast by Precision Castparts Corp. and Avio s.p.a. Machining of the Stage 6, and Stage 7 LPT blades is performed by Moeller Manufacturing. An alternate pathway for production of the gamma TiAl blades for the GEnx and GE9x engines using additive manufacturing is being explored.
In 2019 a new 55g lightweight version of the Omega Seamaster wristwatch was made, using gamma titanium aluminide for the case, backcase and crown, and a titanium dial and mechanism in Ti 6/4 (grade 5). The retail price of this watch at £37,240 was nine times that of the basic Seamaster and comparable to the top of the range platinum-cased version with a moonphase complication. | 1 | Applied and Interdisciplinary Chemistry |
Due to the paternal inheritance, Y-haplotypes provide information about the genetic ancestry of the male population. To investigate this population history, and to provide estimates for haplotype frequencies in criminal casework, the "Y haplotype reference database (YHRD)" has been created in 2000 as an online resource. It currently comprises more than 300,000 minimal (8 locus) haplotypes from world-wide populations. | 1 | Applied and Interdisciplinary Chemistry |
Neubauer was born in Karlsbad (then in Bohemia) to physician Wolfgang and Hedwig Arnstein née Sadler. In 1892 he passed the examination for qualifying admission to a university after studying at the humanistic gymnasium of Chomutov. He then went to the German University in Prague he received a medical degree in 1898 and became interested in physiological chemistry through the influence of Karl H. Huppert. He then joined as an assistant to Friedrich von Müller at Basel. He moved to Munich in 1902. In 1908 he joined the University of Munich and served in a reserve hospital during World War I. His major work in this period was on amino acid metabolism in human health and disease. Neubauer and Konrad Fromherz examined the role of pyruvic acid in fermentation. He innovated several clinical diagnostics including tests of peptolytic activity. Gastric juice incubated with glycyl-tryptophan for twenty four hours tested with bromine to see if free tryptophan causes a rose-violet colour was used as an indication of stomach carcinoma. In 1918 he became head physician at Schwabinger Hospital, working there until his dismissal by the Nazi government in June 1933 as a person of Jewish ancestry. In 1920 he developed a blood pressure measuring device and still later a measuring slide (known as a Neubauer slide or Neubauer counting chamber) for counting cells under a microscope. With assistance and support from The Society for the Protection of Science and Learning, he emigrated to England in 1939 along with his wife Lilly Caroline (1876-1962, who was married to composer Fritz Cassirer until his death) and worked in Oxford for the remainder of his life. His contributions included studies on arsenic and other chemicals as carcinogens.
Neubauer's students included Siegfried Thannhauser, Rudolf Schindler, and Konrad Dobriner. | 1 | Applied and Interdisciplinary Chemistry |
Değirmentepe, a site located 24 km northeast of Melid, is notable as the location of the earliest secure evidence of copper smelting. The site was built on a small natural outcrop in the flood plain about 40m from the Euphrates River. | 1 | Applied and Interdisciplinary Chemistry |
Turbidity currents are traditionally defined as those sediment gravity flows in which sediment is suspended by fluid turbulence.
However, the term "turbidity current" was adopted to describe a natural phenomenon whose exact nature is often unclear. The turbulence within a turbidity current is not always the support mechanism that keeps the sediment in suspension; however it is probable that turbulence is the primary or sole grain support mechanism in dilute currents (<3%). Definitions are further complicated by an incomplete understanding of the turbulence structure within turbidity currents, and the confusion between the terms turbulent (i.e. disturbed by eddies) and turbid (i.e. opaque with sediment). Kneller & Buckee, 2000 define a suspension current as flow induced by the action of gravity upon a turbid mixture of fluid and (suspended) sediment, by virtue of the density difference between the mixture and the ambient fluid. A turbidity current is a suspension current in which the interstitial fluid is a liquid (generally water); a pyroclastic current is one in which the interstitial fluid is gas. | 1 | Applied and Interdisciplinary Chemistry |
The Petrochemical industry typically encounters aggressive corrosive media. These include sulfides and high temperatures. Corrosion control and solutions are thus necessary for the world economy. Scale formation in injection water presents its own problems with regard to corrosion and thus for the corrosion engineer. | 1 | Applied and Interdisciplinary Chemistry |
Second-generation fuels require either higher confinement temperatures or longer confinement time than those required of first-generation fusion fuels, but generate fewer neutrons. Neutrons are an unwanted byproduct of fusion reactions in an energy generation context, because they are absorbed by the walls of a fusion chamber, making them radioactive. They cannot be confined by magnetic fields, because they are not electrically charged. This group consists of deuterium and helium-3. The products are all charged particles, but there may be significant side reactions leading to the production of neutrons.
:H + He → p (14.68 MeV) + He (3.67 MeV) | 0 | Theoretical and Fundamental Chemistry |
For settling particles that are considered individually, i.e. dilute particle solutions, there are two main forces enacting upon any particle. The primary force is an applied force, such as gravity, and a drag force that is due to the motion of the particle through the fluid. The applied force is usually not affected by the particle's velocity, whereas the drag force is a function of the particle velocity.
For a particle at rest no drag force will be exhibited, which causes the particle to accelerate due to the applied force. When the particle accelerates, the drag force acts in the direction opposite to the particles motion, retarding further acceleration, in the absence of other forces drag directly opposes the applied force. As the particle increases in velocity eventually the drag force and the applied force will approximately equate, causing no further change in the particles velocity. This velocity is known as the terminal velocity, settling velocity or fall velocity of the particle. This is readily measurable by examining the rate of fall of individual particles.
The terminal velocity of the particle is affected by many parameters, i.e. anything that will alter the particle's drag. Hence the terminal velocity is most notably dependent upon grain size, the shape (roundness and sphericity) and density of the grains, as well as to the viscosity and density of the fluid. | 0 | Theoretical and Fundamental Chemistry |
VMATs are found in a variety of cell types throughout the body, however, VMAT1 is found exclusively in neuroendocrine cells, in contrast to VMAT2, which is also found in the PNS and CNS. Specifically, VMAT1 is found in chromaffin cells, enterochromaffin cells, and small intensely fluorescent cells (SIFs). Chromaffin cells are responsible for releasing the catecholamines (norepinephrine and epinephrine) into systemic circulation. Enterochromaffin cells are responsible for storing serotonin in the gastrointestinal tract. SIFs are interneurons associated with the sympathetic nervous system which are managed by dopamine. | 1 | Applied and Interdisciplinary Chemistry |
Many of the NGS sequencing protocols rely on the production of a genomic library that contains thousands of fragments of the target nucleic acids that will then be sequenced by proper technologies. According to the sequencing methods to be used, libraries can be created differently (in the case of the Ion Torrent technology RNA fragments are directly attached to a magnetic bead through an adapter, while for Illumina sequencing, the RNA fragments are firstly ligated to the adapters and then attached to the surface of a plate): generally, universal adapters A and B (containing well known sequences comprehensive of Unique Molecular Identifiers that are used to quantify small RNAs in a sample and sample indexing that allows to discriminate between different RNA molecules deriving from different samples) are ligated to the 5 and 3 ends of the RNA fragments thanks to the activity of the T4 RNA ligase 2 truncated. After the adapters are ligated to both ends of the small RNAs, retrotranscription occurs producing complementary DNA molecules (cDNAs) which will be, eventually, amplified by different amplification techniques depending on the sequencing protocol that is being followed (Ion Torrent exploits the emulsion PCR, while Illumina requires a bridge PCR) in order to obtain up to billions of amplicons to be sequenced. Besides the regular PCR mix, masking oligonucleotides targeting 5.8s rRNA are added to increase sensitivity to small RNA targets and to improve the amplification results. Caution has to be used, as RNA samples are prone to degradation, and further improvement of this technique should be oriented towards the elimination of adapter dimers. Some specific RNA modifications (such as 5′ hydroxyl (5′-OH), 3′-phosphate (3′-P) and 2′,3′-cyclic phosphate (2′3′-cP)) can block the adapter ligation process, while some other RNA modifications ( such as m1A, m3C, m1G and m22G) can interfere with reverse transcription process. Small RNA bearing one or more of these modifications are often inefficiently and incompletely converted into cDNAs, leading to challenges with their detection and quantitation by deep sequencing, which can be overcome by enzyme (such as PNK and AlkB) pre-treatment. | 1 | Applied and Interdisciplinary Chemistry |
Bismuth compounds have been used because of their astringent, antiphlogistic, bacteriostatic, and disinfecting actions. In dermatology bismuth subgallate is still used in vulnerary salves and powders as well as in antimycotics. In the past, bismuth has also been used to treat syphilis and malaria. | 1 | Applied and Interdisciplinary Chemistry |
Diphosphene is inert to ground-state oxygen but can be oxidized by triplet oxygen to give a mixture of phosphine oxides and hydroxy benzophosphole oxide. Compared to oxygen involved oxidation, reaction of diphosphene with ozone is much more rapid and indicates a 2:1 (ozone:diphosphene) stoichiometry. Ozonolysis of bis[tris(trimethylsilyl)methyl]diphosphene (TsiP) gives a cyclic diperoxides. | 0 | Theoretical and Fundamental Chemistry |
There are several small molecule inducers that can induce the glyoxalase pathway by either promoting GLO1 function to increase conversion of MG into D-Lactate, which are called GLO1 activators, or by directly reducing MG levels or levels of MG substrate, which are called MG scavengers. GLO1 activators include the synthetic drug candesartan or natural compounds resveratrol, fisetin, the binary combination of trans-resveratrol and hesperetin (tRES-HESP), mangiferin, allyl isothiocyanate, phenethyl isothiocyanate, sulforaphane, and bardoxolone methyl, and MG scavengers include aminoguanidine, alagebrium, and benfotiamine. There is also the small molecule pyridoxamine, which acts as both a GLO1 activator and MG scavenger.
Many inhibitors of GLO1 have been discovered since GLO1 activity tends to be promoted in cancer cells, thus GLO1 serves as a potential therapeutic target for anti-cancer drug treatment and has been the focus of many research studies regarding its regulation in tumor cells. | 1 | Applied and Interdisciplinary Chemistry |
The elements of a eukaryotic and prokaryotic 5′ UTR differ greatly. The prokaryotic 5′ UTR contains a ribosome binding site (RBS), also known as the Shine–Dalgarno sequence (AGGAGGU), which is usually 3–10 base pairs upstream from the initiation codon. In contrast, the eukaryotic 5′ UTR contains the Kozak consensus sequence (ACCAUGG), which contains the initiation codon. The eukaryotic 5′ UTR also contains cis-acting regulatory elements called upstream open reading frames (uORFs) and upstream AUGs (uAUGs) and termination codons, which have a great impact on the regulation of translation (see below). Unlike prokaryotes, 5′ UTRs can harbor introns in eukaryotes. In humans, ~35% of all genes harbor introns within the 5′ UTR. | 1 | Applied and Interdisciplinary Chemistry |
A typical setup uses one laser to create one or two traps. Commonly, two traps are generated by splitting the laser beam into two orthogonally polarized beams. Optical tweezing operations with more than two traps can be realized either by time-sharing a single laser beam among several optical tweezers, or by diffractively splitting the beam into multiple traps. With acousto-optic deflectors or galvanometer-driven mirrors, a single laser beam can be shared among hundreds of optical tweezers in the focal plane, or else spread into an extended one-dimensional trap. Specially designed diffractive optical elements can divide a single input beam into hundreds of continuously illuminated traps in arbitrary three-dimensional configurations. The trap-forming hologram also can specify the mode structure of each trap individually, thereby creating arrays of optical vortices, optical tweezers, and holographic line traps, for example. When implemented with a spatial light modulator, such holographic optical traps also can move objects in three dimensions. Advanced forms of holographic optical traps with arbitrary spatial profiles, where smoothness of the intensity and the phase are controlled, find applications in many areas of science, from micromanipulation to ultracold atoms.
Ultracold atoms could also be used for realization of quantum computers. | 1 | Applied and Interdisciplinary Chemistry |
Kinetic isotope effect measurement at natural abundance is a simple general method for measuring kinetic isotope effects (KIE) for chemical reactions performed with materials of natural abundance. This technique for measuring KIEs overcomes many limitations of previous KIE measurement methods. KIE measurements from isotopically labeled materials require a new synthesis for each isotopically labeled material (a process often prohibitively difficult), a competition reaction, and an analysis. The KIE measurement at natural abundance avoids these issues by taking advantage of high precision quantitative techniques (nuclear magnetic resonance spectroscopy, isotope-ratio mass spectrometry) to site selectively measure kinetic fractionation of isotopes, in either product or starting material for a given chemical reaction. | 0 | Theoretical and Fundamental Chemistry |
In organic chemistry, an alicyclic compound contains one or more all-carbon rings which may be either saturated or unsaturated, but do not have aromatic character. Alicyclic compounds may have one or more aliphatic side chains attached.
The simplest alicyclic compounds are the monocyclic cycloalkanes: cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, and so on. Bicyclic alkanes include bicycloundecane, decalin, and housane. Polycyclic alkanes include cubane, basketane, and tetrahedrane.
Spiro compounds have two or more rings that are connected through only one carbon atom.
The mode of ring-closing in the formation of many alicyclic compounds can be predicted by Baldwin's rules.
Otto Wallach, a German chemist, received the 1910 Nobel Prize in Chemistry for his work on alicyclic compounds.
__TOC__ | 0 | Theoretical and Fundamental Chemistry |
Calmodulin plays an important role in excitation contraction (EC) coupling and the initiation of the cross-bridge cycling in smooth muscle, ultimately causing smooth muscle contraction. In order to activate contraction of smooth muscle, the head of the myosin light chain must be phosphorylated. This phosphorylation is done by myosin light chain (MLC) kinase. This MLC kinase is activated by a calmodulin when it is bound by calcium, thus making smooth muscle contraction dependent on the presence of calcium, through the binding of calmodulin and activation of MLC kinase.
Another way that calmodulin affects muscle contraction is by controlling the movement of Ca across both the cell and sarcoplasmic reticulum membranes. The Ca channels, such as the ryanodine receptor of the sarcoplasmic reticulum, can be inhibited by calmodulin bound to calcium, thus affecting the overall levels of calcium in the cell. Calcium pumps take calcium out of the cytoplasm or store it in the endoplasmic reticulum and this control helps regulate many downstream processes.
This is a very important function of calmodulin because it indirectly plays a role in every physiological process that is affected by smooth muscle contraction such as digestion and contraction of arteries (which helps distribute blood and regulate blood pressure). | 1 | Applied and Interdisciplinary Chemistry |
The first known use of pipes was in Ancient Egypt. The Pyramid of Sahure, completed around the 25th century BC, included a temple with an elaborate drainage system including more than of copper piping.
When steel pipes were introduced in 19th century, they initially were riveted, and later clamped with H-shaped bars, until by the early 1930s these methods were replaced by welding, which is still widely used today. | 1 | Applied and Interdisciplinary Chemistry |
In geochemistry, paleoclimatology, and paleoceanography δC (pronounced "delta c thirteen") is an isotopic signature, a measure of the ratio of the two stable isotopes of carbon—C and C—reported in parts per thousand (per mil, ‰). The measure is also widely used in archaeology for the reconstruction of past diets, particularly to see if marine foods or certain types of plants were consumed.
The definition is, in per mille:
where the standard is an established reference material.
δC varies in time as a function of productivity, the signature of the inorganic source, organic carbon burial, and vegetation type. Biological processes preferentially take up the lower mass isotope through kinetic fractionation. However some abiotic processes do the same. For example, methane from hydrothermal vents can be depleted by up to 50%. | 0 | Theoretical and Fundamental Chemistry |
Being an endothermic reaction, heat is applied to initiate and sustain the reaction. This heat requirement may be very high. To keep reaction temperatures low, the processes are operated under pressure. The rotary kiln is typically used in dolomite calcination. In the rotary kiln, the raw material, calcinated dolomite, is mixed with the finely ground reducing agent, ferrosillicone and the catalyst, fluorite. The materials are mixed together and pressed into sphere shaped pellets and the mixed materials are charged into cylindrical nickel chromium steel retorts. A number of retorts are placed in a furnace in sealed paper bags to avoid moisture absorption so that calcined dolomite activity doesn't reduce magnesium yield. The pellets are then placed into a reduction tank and heated to 1200 °C. The inside of the furnace is vacuumed with a 13.3 Pa or higher, to produce magnesium vapour. Magnesium crystals are removed from the condensers, slag is removed as a solid and the retort is recharged. The crude magnesium is refined via flux, and commercial magnesium ingot is produced. | 1 | Applied and Interdisciplinary Chemistry |
* Molecular mass of the crosslinked polymer.
* Molecular weight of the crystallizable polymer.
* Degree of crosslinking.
* Phase separation.
* Moduli of the original polymers and proportion in the copolymer.
* Moisture (in polymers susceptible to moisture degradation).
* Cooling speed. | 0 | Theoretical and Fundamental Chemistry |
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