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All organisms metabolize sulfur, and it is incorporated into the structure of proteins, polysaccharides, steroids, and many coenzymes. The biological pathway by which an organism takes up and/or removes sulfur can have significant impacts on the sulfur isotope composition of the organism and its environment.
Microorganisms that consume and reduce sulfate in relatively large quantities perform a different pathway of sulfur uptake called dissimilatory sulfate reduction. These organisms use sulfate reduction as an energy source as opposed to a way to synthesize new cell components, and remove the resulting sulfide as a waste product. Microbial sulfate reduction has been demonstrated to fractionate sulfur isotopes in bacteria, with some studies showing a dependence upon sulfate concentration and/or temperature. Studies examining dozens of species of dissimilatory sulfate reducing microbes have observed sulfur isotope fractionations ranging from −65.6‰ to 0‰.
Some organisms take in relatively small amounts of sulfate in a process called assimilatory sulfate reduction, for the purpose of synthesizing compounds that contain sulfur, such as the amino acids methionine and cysteine that can then be used to make proteins. In phytoplankton, most of the sulfur taken up through assimilatory sulfate reduction is incorporated into biomass as proteins (~35%), sulfate esters (~20%), and low-weight sulfur-containing compounds (~40%). Literature on the isotopic fractionation effects of the assimilatory sulfate reduction pathway is much more limited than that discussing dissimilatory sulfate reduction, but some sources report slight isotopic variations (δS = −4.4‰ to +0.5‰) in the resulting organic sulfur relative to the surrounding sulfate.
While dissimilatory sulfate reduction and assimilatory sulfate reduction are two of the most common pathways by which organisms take up and utilize sulfate, there are many other pathways by which living things take up sulfur. For example, sulfur oxidation of compounds like hydrogen sulfide and elemental sulfur is performed by lithotrophic bacteria and chemosynthetic archaea. Most animals obtain sulfur directly from the methionine and cysteine in the protein they consume. | 0 | Theoretical and Fundamental Chemistry |
There are a variety of architectures possible for nonlinear copolymers. Beyond grafted and star polymers discussed below, other common types of branched copolymers include brush copolymers and comb copolymers. | 0 | Theoretical and Fundamental Chemistry |
Fiber-reinforced polymers (FRP) are commonly used by civil engineers in their structures. FRPs respond linear-elastically to axial stress, making them a great material to hold a load. FRPs are usually in a laminate formation with each lamina having unidirectional fibers, typically carbon or glass, embedded within a layer of light polymer matrix material. FRPs have great resistance against environmental exposure and great durability. | 0 | Theoretical and Fundamental Chemistry |
Electromagnetic radiation is emitted by a light source and linearly polarized by a polarizer. It can pass through an optional compensator (retarder, quarter wave plate) and falls onto the sample. After reflection the radiation passes a compensator (optional) and a second polarizer, which is called an analyzer, and falls into the detector. Instead of the compensators, some ellipsometers use a phase-modulator in the path of the incident light beam. Ellipsometry is a specular optical technique (the angle of incidence equals the angle of reflection). The incident and the reflected beam span the plane of incidence. Light which is polarized parallel to this plane is named p-polarized. A polarization direction perpendicular is called s-polarized (s-polarised), accordingly. The "s" is contributed from the German "" (perpendicular). | 0 | Theoretical and Fundamental Chemistry |
The intake of radioactive material can occur through four pathways:
*inhalation of airborne contaminants such as radon
*ingestion of contaminated food or liquids
*absorption of vapours such as tritium oxide through the skin
*injection of medical radioisotopes such as technetium-99m
Some artificial radioisotopes such as iodine-131 are chemically identical to natural isotopes needed by the body, and may be more readily absorbed if the individual has a deficit of that element. For instance, Potassium iodide (KI), administered orally immediately after exposure, may be used to protect the thyroid from ingested radioactive iodine in the event of an accident or attack at a nuclear power plant, or the detonation of a nuclear explosive which would release radioactive iodine.
Other radioisotopes have an affinity for particular tissues, such as plutonium into bone, and may be retained there for years in spite of their foreign nature.
In summary, not all radiation is harmful. The radiation can be absorbed through multiple pathways, varying due to the circumstances of the situation. If the radioactive material is necessary, it can be ingested orally via stable isotopes of specific elements. This is only suggested to those that have a lack of these elements however, because radioactive material can go from healthy to harmful with very small amounts. The most harmful way to absorb radiation is that of absorption because it is almost impossible to control how much will enter the body. | 0 | Theoretical and Fundamental Chemistry |
Several analytical methods are used for qualitative and quantitative determination of peroxides. A simple qualitative detection of peroxides is carried out with the iodine-starch reaction. Here peroxides, hydroperoxides or peracids oxidize the added potassium iodide into iodine, which reacts with starch producing a deep-blue color. Commercial paper indicators using this reaction are available. This method is also suitable for quantitative evaluation, but it can not distinguish between different types of peroxide compounds. Discoloration of various indigo dyes in presence of peroxides is used instead for this purpose. For example, the loss of blue color in leuco-methylene blue is selective for hydrogen peroxide.
Quantitative analysis of hydroperoxides can be performed using potentiometric titration with lithium aluminium hydride. Another way to evaluate the content of peracids and peroxides is the volumetric titration with alkoxides such as sodium ethoxide. | 0 | Theoretical and Fundamental Chemistry |
The resonance frequency of a nuclear spin depends on the strength of the magnetic field at the nucleus, which can be modified by isotropic (e.g. chemical shift, isotropic J-coupling) and anisotropic interactions (e.g. chemical shift anisotropy, dipolar interactions). In a classical liquid-state NMR experiment, molecular tumbling coming from Brownian motion averages anisotropic interactions to zero and they are therefore not reflected in the NMR spectrum. However, in media with no or little mobility (e.g. crystalline powders, glasses, large membrane vesicles, molecular aggregates), anisotropic local fields or interactions have substantial influence on the behaviour of nuclear spins, which results in the line broadening of the NMR spectra. | 0 | Theoretical and Fundamental Chemistry |
Shang et al. discovered the decarboxylative coupling of potassium oxalate monoesters with aryl halides to obtain aryl or alkenyl esters. | 0 | Theoretical and Fundamental Chemistry |
Most pharmaceuticals are small molecules, although some drugs can be proteins (e.g., insulin and other biologic medical products). With the exception of therapeutic antibodies, many proteins are degraded if administered orally and most often cannot cross cell membranes. Small molecules are more likely to be absorbed, although some of them are only absorbed after oral administration if given as prodrugs. One advantage that small molecule drugs (SMDs) have over "large molecule" biologics is that many small molecules can be taken orally whereas biologics generally require injection or another parenteral administration. Small molecule drugs are also typically simpler to manufacture and cheaper for the purchaser. A downside is that not all targets are amenable to modification with small-molecule drugs; bacteria and cancers are often resistant to their effects. | 1 | Applied and Interdisciplinary Chemistry |
It was agreed that there would be a World Congress every three years, with each Chapter organizing its own conference in the intervening two years. | 1 | Applied and Interdisciplinary Chemistry |
Rare earth oxides exhibit intrinsic hydrophobicity, and hence can be used in thermally stable heat exchangers and other applications involving high-temperature hydrophobicity. The presence of oxygen vacancies at surfaces of ceria or other rare earth oxides is instrumental in governing surface wettability. Adsorption of water at oxide surfaces can occur as molecular adsorption, in which HO molecules remain intact at the terminated surface, or as dissociative adsorption, in which OH and H are adsorbed separately at solid surfaces. The presence of oxygen vacancies is generally found to enhance hydrophobicity while promoting dissociative adsorption. | 0 | Theoretical and Fundamental Chemistry |
Melted fusible alloys can be used as coolants as they are stable under heating and can give much higher thermal conductivity than most other coolants; particularly with alloys made with a high thermal conductivity metal such as indium or sodium. Metals with low neutron cross-section are used for cooling nuclear reactors.
Such alloys are used for making the fusible plugs inserted in the furnace crowns of steam boilers, as a safeguard in the event of the water level being allowed to fall too low. When this happens the plug, being no longer covered with water, is heated to such a temperature that it melts and allows the contents of the boiler to escape into the furnace. In automatic fire sprinklers the orifices of each sprinkler is closed with a plug that is held in place by fusible metal, which melts and liberates the water when, owing to an outbreak of fire in the room, the temperature rises above a predetermined limit.
Bismuth on solidification expands by about 3.3% by volume. Alloys with at least half of bismuth display this property too. This can be used for mounting of small parts, e.g. for machining, as they will be tightly held. | 1 | Applied and Interdisciplinary Chemistry |
A screw displacement (also screw operation or rotary translation) is the composition of a rotation by an angle φ about an axis (called the screw axis) with a translation by a distance d along this axis. A positive rotation direction usually means one that corresponds to the translation direction by the right-hand rule. This means that if the rotation is clockwise, the displacement is away from the viewer. Except for φ = 180°, we have to distinguish a screw displacement from its mirror image. Unlike for rotations, a righthand and lefthand screw operation generate different groups.
The combination of a rotation about an axis and a translation in a direction perpendicular to that axis is a rotation about a parallel axis. However, a screw operation with a nonzero translation vector along the axis cannot be reduced like that. Thus the effect of a rotation combined with any translation is a screw operation in the general sense, with as special cases a pure translation, a pure rotation and the identity. Together these are all the direct isometries in 3D.
In crystallography, a screw axis symmetry is a combination of rotation about an axis and a translation parallel to that axis which leaves a crystal unchanged. If φ = 360°/n for some positive integer n, then screw axis symmetry implies translational symmetry with a translation vector which is n times that of the screw displacement.
Applicable for space groups is a rotation by 360°/n about an axis, combined with a translation along the axis by a multiple of the distance of the translational symmetry, divided by n. This multiple is indicated by a subscript. So, 6 is a rotation of 60° combined with a translation of 1/2 of the lattice vector, implying that there is also 3-fold rotational symmetry about this axis. The possibilities are 2, 3, 4, 4, 6, 6, and 6, and the enantiomorphous 3, 4, 6, and 6.
Considering a screw axis n, if g is the greatest common divisor of n and m, then there is also a g-fold rotation axis. When n/g screw operations have been performed, the displacement will be m/g, which since it is a whole number means one has moved to an equivalent point in the lattice, while carrying out a rotation by 360°/g. So 4, 6 and 6 create two-fold rotation axes, while 6 creates a three-fold axis.
A non-discrete screw axis isometry group contains all combinations of a rotation about some axis and a proportional translation along the axis (in rifling, the constant of proportionality is called the twist rate); in general this is combined with k-fold rotational isometries about the same axis (k ≥ 1); the set of images of a point under the isometries is a k-fold helix; in addition there may be a 2-fold rotation about a perpendicularly intersecting axis, and hence a k-fold helix of such axes. | 0 | Theoretical and Fundamental Chemistry |
Reactive oxygen species or ROS are species such as superoxide, hydrogen peroxide, and hydroxyl radical, commonly associated with cell damage. ROS form as a natural by-product of the normal metabolism of oxygen and have important roles in cell signaling.
Two important oxygen-centered radicals are superoxide and hydroxyl radical. They derive from molecular oxygen under reducing conditions. However, because of their reactivity, these same radicals can participate in unwanted side reactions resulting in cell damage. Excessive amounts of these radicals can lead to cell injury and death, which may contribute to many diseases such as cancer, stroke, myocardial infarction, diabetes and major disorders. Many forms of cancer are thought to be the result of reactions between radicals and DNA, potentially resulting in mutations that can adversely affect the cell cycle and potentially lead to malignancy. Some of the symptoms of aging such as atherosclerosis are also attributed to radical induced oxidation of cholesterol to 7-ketocholesterol. In addition radicals contribute to alcohol-induced liver damage, perhaps more than alcohol itself. Radicals produced by cigarette smoke are implicated in inactivation of alpha 1-antitrypsin in the lung. This process promotes the development of emphysema.
Oxybenzone has been found to form radicals in sunlight, and therefore may be associated with cell damage as well. This only occurred when it was combined with other ingredients commonly found in sunscreens, like titanium oxide and octyl methoxycinnamate.
ROS attack the polyunsaturated fatty acid, linoleic acid, to form a series of 13-hydroxyoctadecadienoic acid and 9-hydroxyoctadecadienoic acid products that serve as signaling molecules that may trigger responses that counter the tissue injury which caused their formation. ROS attacks other polyunsaturated fatty acids, e.g. arachidonic acid and docosahexaenoic acid, to produce a similar series of signaling products.
Reactive oxygen species are also used in controlled reactions involving singlet dioxygen known as type II photooxygenation reactions after Dexter energy transfer (triplet-triplet annihilation) from natural triplet dioxygen and triplet excited state of a photosensitizer. Typical chemical transformations with this singlet dioxygen species involve, among others, conversion of cellulosic biowaste into new poylmethine dyes. | 1 | Applied and Interdisciplinary Chemistry |
Urine testing is the most common method of testing for ketones. Urine test strips utilize a nitroprusside reaction with acetoacetate to give a semi-quantitative measure based on color change of the strip. Although beta-hydroxybutyrate is the predominant circulating ketone, urine test strips only measure acetoacetate. Urinary ketones often correlate poorly with serum levels because of variability in excretion of ketones by the kidney, influence of hydration status, and renal function. | 1 | Applied and Interdisciplinary Chemistry |
When Rockwell International purchased North American Aviation, it also gained ownership of the NATWT. The NATWT was then gifted to the University of California, Los Angeles (UCLA) in 1998, with the intention of NATWT becoming a university research facility. It became known as the Micro Craft Trisonic Wind Tunnel. In 2007, UCLA decided to close the trisonic wind tunnel, citing environmental issues.
The last test to be conducted at TWT was completed on August 28, 2007. It was designated as test TWT 807. TWT was demolished in 2009. | 1 | Applied and Interdisciplinary Chemistry |
Persons with certain genetic variations in human leukocyte antigens (HLAs) are under increased risk of developing skin reactions such as acute generalized exanthematous pustulosis (AGEP), but also severe ones such as Stevens–Johnson and DRESS syndrome, under treatment with carbamazepine and drugs with related chemical structures. This is true for the HLA-A*3101 allele, which occurs in 2 to 5% of Europeans and 10% of Japanese people, and the HLA-B*1502 allele, which is mainly found in people of Asian descent. Theoretically, this may also apply to ESL. | 0 | Theoretical and Fundamental Chemistry |
Most of the known actions of Ang II are mediated through the AT receptors, for example vasoconstriction, aldosterone release, renal sodium reabsorption and vasopressin secretion. The AT receptor also takes part in regulation of blood pressure and renal function but mediates antagonistic effects compared to the AT receptor. | 1 | Applied and Interdisciplinary Chemistry |
Radioactive waste comes from a number of sources. In countries with nuclear power plants, nuclear armament, or nuclear fuel treatment plants, the majority of waste originates from the nuclear fuel cycle and nuclear weapons reprocessing. Other sources include medical and industrial wastes, as well as naturally occurring radioactive materials (NORM) that can be concentrated as a result of the processing or consumption of coal, oil, and gas, and some minerals, as discussed below. | 0 | Theoretical and Fundamental Chemistry |
Electropositivity is a measure of an element's ability to donate electrons, and therefore form positive ions; thus, it is antipode to electronegativity.
Mainly, this is an attribute of metals, meaning that, in general, the greater the metallic character of an element the greater the electropositivity. Therefore, the alkali metals are the most electropositive of all. This is because they have a single electron in their outer shell and, as this is relatively far from the nucleus of the atom, it is easily lost; in other words, these metals have low ionization energies.
While electronegativity increases along periods in the periodic table, and decreases down groups, electropositivity decreases along periods (from left to right) and increases down groups. This means that elements in the upper right of the periodic table of elements (oxygen, sulfur, chlorine, etc.) will have the greatest electronegativity, and those in the lower-left (rubidium, caesium, and francium) the greatest electropositivity. | 0 | Theoretical and Fundamental Chemistry |
* Current capacity limited by anode mass and self consumption at low current density.
* Lower driving voltage means the anodes may not work in high-resistivity environments.
* Often requires that the protected structure be electrically isolated from other structures and ground.
* Anodes are heavy and will increase water resistance on moving structures or pipe interiors.
* Where D.C. power is available, electrical energy can be obtained more cheaply than by galvanic anodes.
* Where large arrays are used, wiring is needed due to high current flow and need to keep resistance losses low.
* Anodes must be carefully placed to avoid interfering with water flow into the propeller.
* To retain effectiveness, the anodes must be inspected and/or replaced as part of normal maintenance. | 0 | Theoretical and Fundamental Chemistry |
In fluid mechanics, pipe flow is a type of fluid flow within a closed conduit, such as a pipe, duct or tube. It is also called as Internal flow. The other type of flow within a conduit is open channel flow. These two types of flow are similar in many ways, but differ in one important aspect. Pipe flow does not have a free surface which is found in open-channel flow. Pipe flow, being confined within closed conduit, does not exert direct atmospheric pressure, but does exert hydraulic pressure on the conduit.
Not all flow within a closed conduit is considered pipe flow. Storm sewers are closed conduits but usually maintain a free surface and therefore are considered open-channel flow. The exception to this is when a storm sewer operates at full capacity, and then can become pipe flow.
Energy in pipe flow is expressed as head and is defined by the Bernoulli equation. In order to conceptualize head along the course of flow within a pipe, diagrams often contain a hydraulic grade line (HGL). Pipe flow is subject to frictional losses as defined by the Darcy-Weisbach formula. | 1 | Applied and Interdisciplinary Chemistry |
There are also reports of antihomoaromatic compounds. Just as aromatic compounds exhibit exceptional stability, antiaromatic compounds, which deviate from Huckel's rule and contain a closed loop of 4n π electrons, are relatively unstable. The bridged bicyclo[3.2.1]octa-3,6-dien-2-yl cation contains only 4 π electrons, and is therefore "bishomoantiaromatic." A series of theoretical calculations confirm that it is indeed less stable than the corresponding allyl cation.
Similarly, a substituted bicyclo[3.2.1]octa-3,6-dien-2-yl cation (the 2-(4'-Fluorophenyl) bicyclo[3.2.1]oct-3,6-dien-2-yl cation) was also shown to be an antiaromate when compared to its corresponding allyl cation, corroborated by theoretical calculations as well as by NMR analysis. | 0 | Theoretical and Fundamental Chemistry |
Further alloys with low melting points are at , at and at . The alloy consisting of 40.8 % caesium, 11.8 % sodium and 47.4 % potassium has a melting point of . | 1 | Applied and Interdisciplinary Chemistry |
CTCF binds to the consensus sequence CCGCGNGGNGGCAG (in IUPAC notation). This sequence is defined by 11 zinc finger motifs in its structure. CTCF's binding is disrupted by CpG methylation of the DNA it binds to. On the other hand, CTCF binding may set boundaries for the spreading of DNA methylation. In recent studies, CTCF binding loss is reported to increase localized CpG methylation, which reflected another epigenetic remodeling role of CTCF in human genome.
CTCF binds to an average of about 55,000 DNA sites in 19 diverse cell types (12 normal and 7 immortal) and in total 77,811 distinct binding sites across all 19 cell types.
CTCF's ability to bind to multiple sequences through the usage of various combinations of its zinc fingers earned it the status of a “multivalent protein”. More than 30,000 CTCF binding sites have been characterized. The human genome contains anywhere between 15,000 and 40,000 CTCF binding sites depending on cell type, suggesting a widespread role for CTCF in gene regulation. In addition CTCF binding sites act as nucleosome positioning anchors so that, when used to align various genomic signals, multiple flanking nucleosomes can be readily identified. On the other hand, high-resolution nucleosome mapping studies have demonstrated that the differences of CTCF binding between cell types may be attributed to the differences in nucleosome locations. Methylation loss at CTCF-binding site of some genes has been found to be related to human diseases, including male infertility. | 1 | Applied and Interdisciplinary Chemistry |
Lineatin is a monoterprene with unique tricyclic acetal structure. Most of the studies regarding lineatin were focused on the total synthesis; little attentions were put on its biosynthesis. It is suggested that lineatin is derived through oxidation and cyclization of a monoterponid precursor, but no experimental has been done on proving this route. Based on its partial structure similarity to iridoid class of terprenoids, here, a possible biosynthesis pathway was proposed and outlined in figure 2. | 0 | Theoretical and Fundamental Chemistry |
Several other minerals, such as the gemstone topaz, contain fluoride. Fluoride is not significant in seawater or brines, unlike the other halides, because the alkaline earth fluorides precipitate out of water. Commercially insignificant quantities of organofluorines have been observed in volcanic eruptions and in geothermal springs. Their ultimate origin (from biological sources or geological formation) is unclear.
The possibility of small amounts of gaseous fluorine within crystals has been debated for many years. One form of fluorite, antozonite, has a smell suggestive of fluorine when crushed. The mineral also has a dark black color, perhaps from free calcium (not bonded to fluoride). In 2012, a study reported detection of trace quantities (0.04% by weight) of diatomic fluorine in antozonite. It was suggested that radiation from small amounts of uranium within the crystals had caused the free fluorine defects. | 0 | Theoretical and Fundamental Chemistry |
Mander returned to Australia in 1966 to become a lecturer in organic chemistry at the University of Adelaide. He was promoted to Senior Lecturer in organic chemistry in 1970, where he remained until 1975. During this time Mander visited the University of Cambridge to research "...pathways to the pigments of life". In 1977, he served as a Fulbright Senior Scholar at the California Institute of Technology. He was a distinguished Alumnus Professor at the University of Auckland in 1992 and an Eminent Scientist of RIKEN at Wako, in Saitama Prefecture, Japan from 1995 to 1996.
In Australia, he relocated to the Australian National University Research School of Chemistry as a Senior Fellow. He retired in 2002 but retained the title of Professor Emeritus at the Australian National University.
Notable students of Mander's include Jacqueline Whalley, professor at Auckland University of Technology. | 0 | Theoretical and Fundamental Chemistry |
In metallurgy, materials science and structural geology, subgrain rotation recrystallization is recognized as an important mechanism for dynamic recrystallisation. It involves the rotation of initially low-angle sub-grain boundaries until the mismatch between the crystal lattices across the boundary is sufficient for them to be regarded as grain boundaries. This mechanism has been recognized in many minerals (including quartz, calcite, olivine, pyroxenes, micas, feldspars, halite, garnets and zircons) and in metals (various magnesium, aluminium and nickel alloys). | 1 | Applied and Interdisciplinary Chemistry |
* Jean-Claude Duplessy was one of the lead authors of the "paleoclimatology" chapter of the report of the Intergovernmental Panel on Climate Change (IPCC), which was published in 2007.
* His mission was to coordinate the activities of some twenty scientists from the international community with the objective of showing how the study of ancient climates makes it possible to better understand the mechanisms that could come into play in a world whose climate is disrupted by greenhouse gas and dust emissions. He was co-recipient, with his IPCC colleagues, of the 2007 Nobel Peace Prize in this capacity.
* He has been a member of the French Academy of Sciences since 2011 in the "Sciences of the Universe" section.
* He is a member of the European Academy of Sciences, Academia europaea since 1989
* Winner of the Aimé Berthé Prize of the Academy of Sciences (1987)
* Milankovitch Medal of the EGS (1995).
* Winner of the Georges Lemaître Prize of the Catholic University of Louvain (1997)
* Dr Honoris Causa from the University of Kiel, Germany (2003).
* Grand Prix Louis D of the Institut de France 2004.
* Prestwich Prize of the French Geological Society 2004.
* Grand Prix Dolomieu of BRGM awarded by the Academy of Sciences in 2004. | 0 | Theoretical and Fundamental Chemistry |
In physics, work output is the work done by a simple machine, compound machine, or any type of engine model. In common terms, it is the energy output, which for simple machines is always less than the energy input, even though the forces may be drastically different.
In [thermodynamics], work output can refer to the thermodynamic work done by a heat engine, in which case the amount of work output must be less than the input as energy is lost to heat, as determined by the engine's efficiency. | 0 | Theoretical and Fundamental Chemistry |
Hydroamination is well-established technology for generating fragrances from myrcene. In this conversion, diethylamine adds across the diene substituent, the reaction being catalyzed by lithium diethylamide. Intramolecular hydroaminations were reported by Tobin J. Marks in 1989 using metallocene derived from rare-earth metals such as lanthanum, lutetium, and samarium. Catalytic rates correlated inversely with the ionic radius of the metal, perhaps as a consequence of steric interference from the ligands. In 1992, Marks developed the first chiral hydroamination catalysts by using a chiral auxiliary, which were the first hydroamination catalysts to favor only one specific stereoisomer. Chiral auxiliaries on the metallocene ligands were used to dictate the stereochemistry of the product. The first non-metallocene chiral catalysts were reported in 2003, and used bisarylamido and aminophenolate ligands to give higher enantioselectivity. | 0 | Theoretical and Fundamental Chemistry |
One might expect that larger side chains would result in more restrictions and consequently a smaller allowable region in the Ramachandran plot, but the effect of side chains is small. In practice, the major effect seen is that of the presence or absence of the methylene group at Cβ. Glycine has only a hydrogen atom for its side chain, with a much smaller van der Waals radius than the CH, CH, or CH group that starts the side chain of all other amino acids. Hence it is least restricted, and this is apparent in the Ramachandran plot for glycine (see Gly plot in gallery) for which the allowable area is considerably larger. In contrast, the Ramachandran plot for proline, with its 5-membered-ring side chain connecting Cα to backbone N, shows a limited number of possible combinations of ψ and φ (see Pro plot in gallery). The residue preceding proline ("pre-proline") also has limited combinations compared to the general case. | 1 | Applied and Interdisciplinary Chemistry |
Sulfonamides can be prepared in the laboratory in many ways. The classic approach entails the reaction of sulfonyl chlorides with an amine.
A base such as pyridine is typically added to absorb the HCl that is generated. Illustrative is the synthesis of sulfonylmethylamide.
The reaction of primary and secondary amines with benzenesulfonyl chloride is the basis of the Hinsberg reaction, a method for detecting primary and secondary amines.
Sulfonamides undergo a variety of acid-base reactions. The N-H bond can be deprotonated. The alkylsulfonamides can be deprotonated at carbon. Arylsulfonamides undergo ortho-lithiation. | 0 | Theoretical and Fundamental Chemistry |
Biofuels that are produced through hydrothermal liquefaction are carbon neutral, meaning that there are no net carbon emissions produced when burning the biofuel. The plant materials used to produce bio-oils use photosynthesis to grow, and as such consume carbon dioxide from the atmosphere. The burning of the biofuels produced releases carbon dioxide into the atmosphere, but is nearly completely offset by the carbon dioxide consumed from growing the plants, resulting in a release of only 15-18 g of CO per kWh of energy produced. This is substantially lower than the releases rate of fossil fuel technologies, which can range from releases of 955 g/kWh (coal), 813 g/kWh (oil), and 446 g/kWh (natural gas). Recently, Steeper Energy announced that the carbon intensity (CI) of its Hydrofaction™ oil is 15 COeq/MJ according to [http://www.ghgenius.ca/ GHGenius model] (version 4.03a), while diesel fuel is 93.55 COeq/MJ.
Hydrothermal liquefaction is a clean process that doesn't produce harmful compounds, such as ammonia, NO, or SO. Instead the heteroatoms, including nitrogen, sulfur, and chlorine, are converted into harmless byproducts such as N and inorganic acids that can be neutralized with bases. | 0 | Theoretical and Fundamental Chemistry |
A heterogeneous catalyst consisting of Pd supported by silica-coated FeO/FeO nanoparticles allows the reaction to be heated by electrical induction, and also allows facile magnetic separation of catalyst and product post-reaction. Copper ferrite has been reported as a heterocycle arylation catalyst and can be similarly separated from the reaction with a magnet. | 0 | Theoretical and Fundamental Chemistry |
As the cyclone is essentially a two phase particle-fluid system, fluid mechanics and particle transport equations can be used to describe the behaviour of a cyclone. The air in a cyclone is initially introduced tangentially into the cyclone with an inlet velocity . Assuming that the particle is spherical, a simple analysis to calculate critical separation particle sizes can be established.
If one considers an isolated particle circling in the upper cylindrical component of the cyclone at a rotational radius of from the cyclones central axis, the particle is therefore subjected to drag, centrifugal, and buoyant forces. Given that the fluid velocity is moving in a spiral the gas velocity can be broken into two component velocities: a tangential component, , and an outward radial velocity component . Assuming Stokes law, the drag force in the outward radial direction that is opposing the outward velocity on any particle in the inlet stream is:
Using as the particle's density, the centrifugal component in the outward radial direction is:
The buoyant force component is in the inward radial direction. It is in the opposite direction to the particle's centrifugal force because it is on a volume of fluid that is missing compared to the surrounding fluid. Using for the density of the fluid, the buoyant force is:
In this case, is equal to the volume of the particle (as opposed to the velocity). Determining the outward radial motion of each particle is found by setting Newton's second law of motion equal to the sum of these forces:
To simplify this, we can assume the particle under consideration has reached "terminal velocity", i.e., that its acceleration is zero. This occurs when the radial velocity has caused enough drag force to counter the centrifugal and buoyancy forces. This simplification changes our equation to:
Which expands to:
Solving for we have
Notice that if the density of the fluid is greater than the density of the particle, the motion is (-), toward the center of rotation and if the particle is denser than the fluid, the motion is (+), away from the center. In most cases, this solution is used as guidance in designing a separator, while actual performance is evaluated and modified empirically.
In non-equilibrium conditions when radial acceleration is not zero, the general equation from above must be solved. Rearranging terms we obtain
Since is distance per time, this is a 2nd order differential equation of the form .
Experimentally it is found that the velocity component of rotational flow is proportional to , therefore:
This means that the established feed velocity controls the vortex rate inside the cyclone, and the velocity at an arbitrary radius is therefore:
Subsequently, given a value for , possibly based upon the injection angle, and a cutoff radius, a characteristic particle filtering radius can be estimated, above which particles will be removed from the gas stream. | 1 | Applied and Interdisciplinary Chemistry |
Third-generation fusion fuels produce only charged particles in the primary reactions, and side reactions are relatively unimportant. Since a very small amount of neutrons is produced, there would be little induced radioactivity in the walls of the fusion chamber. This is often seen as the end goal of fusion research. He has the highest Maxwellian reactivity of any 3rd generation fusion fuel. However, there are no significant natural sources of this substance on Earth.
:He + He → 2 p + He (12.86 MeV)
Another potential aneutronic fusion reaction is the proton-boron reaction:
:p + B → 3 He (8.7 MeV)
Under reasonable assumptions, side reactions will result in about 0.1% of the fusion power being carried by neutrons. With 123 keV, the optimum temperature for this reaction is nearly ten times higher than that for the pure hydrogen reactions, the energy confinement must be 500 times better than that required for the D-T reaction, and the power density will be 2500 times lower than for D-T. | 0 | Theoretical and Fundamental Chemistry |
A type of ion exchange chromatography, membrane exchange is a relatively new method of purification designed to overcome limitations of using columns packed with beads. Membrane Chromatographic devices are cheap to mass-produce and disposable unlike other chromatography devices that require maintenance and time to revalidate. There are three types of membrane absorbers that are typically used when separating substances. The three types are flat sheet, hollow fibre, and radial flow. The most common absorber and best suited for membrane chromatography is multiple flat sheets because it has more absorbent volume. It can be used to overcome mass transfer limitations and pressure drop, making it especially advantageous for isolating and purifying viruses, plasmid DNA, and other large macromolecules. The column is packed with microporous membranes with internal pores which contain adsorptive moieties that can bind the target protein. Adsorptive membranes are available in a variety of geometries and chemistry which allows them to be used for purification and also fractionation, concentration, and clarification in an efficiency that is 10 fold that of using beads. Membranes can be prepared through isolation of the membrane itself, where membranes are cut into squares and immobilized. A more recent method involved the use of live cells that are attached to a support membrane and are used for identification and clarification of signaling molecules. | 0 | Theoretical and Fundamental Chemistry |
Mercury has been smelted from cinnabar for thousands of years. Mercury dissolves many metals, such as gold, silver, and tin, to form amalgams (an alloy in a soft paste or liquid form at ambient temperature). Amalgams have been used since 200 BC in China for gilding objects such as armor and mirrors with precious metals. The ancient Romans often used mercury-tin amalgams for gilding their armor. The amalgam was applied as a paste and then heated until the mercury vaporized, leaving the gold, silver, or tin behind. Mercury was often used in mining, to extract precious metals like gold and silver from their ores. | 1 | Applied and Interdisciplinary Chemistry |
Induced gas flotation (IGF) is a water treatment process that clarifies wastewaters (or other waters) by the removal of suspended matter such as oil or solids. The removal is achieved by injecting gas bubbles into the water or wastewater in a flotation tank or basin. The small bubbles adhere to the suspended matter causing the suspended matter to float to the surface of the water where it may then be removed by a skimming device.
Induced gas flotation is very widely used in treating the industrial wastewater effluents from oil refineries, petrochemical and chemical plants, natural gas processing plants and similar industrial facilities. A very similar process known as dissolved air flotation is also used for waste water treatment. Froth flotation is commonly used in the processing of mineral ores.
IGF units in the oil industry do not use air as the flotation medium due to the explosion risk. These IGF units use natural gas or nitrogen to create the bubbles.
__TOC__ | 1 | Applied and Interdisciplinary Chemistry |
Borate anions are largely in the form of the undissociated acid in aqueous solution at physiological pH. No further metabolism occurs in either animals or plants. In animals, boric acid/borate salts are essentially completely absorbed following oral ingestion. Absorption occurs via inhalation, although quantitative data are unavailable. Limited data indicate that boric acid/salts are not absorbed through intact skin to any significant extent, although absorption occurs through skin that is severely abraded. It distributes throughout the body and is not retained in tissues, except for bone, and is rapidly excreted in the urine. | 0 | Theoretical and Fundamental Chemistry |
The adsorbent is separated from the now treated effluent in the sedimentation zone where the density of the adsorbent allows separation by gravitational sedimentation. The treated effluent is allowed to overflow out of the cell. | 0 | Theoretical and Fundamental Chemistry |
The Ilu is a large plesiosaur-like sea creature that is ridden by the Metkayina Clan in place of the Direhorse. Sleek and lithe aquatic reptilian specimen with a long neck, six flippers and rudder-like tail, closely resembling Earths extinct plesiosaur species. Four eyes and two kuru/queue antennae-like neural whips extending from its temples. They are introduced in Avatar: The Way of Water' and are primary domesticated by the Reef People. | 1 | Applied and Interdisciplinary Chemistry |
Large temperature gradients exist in the electrofusion joint during the fusion cycle. The low thermal conductivity of polymers is the main cause of these large gradients. Recent efforts to model the thermal history at various locations using finite element modeling have been successful. | 0 | Theoretical and Fundamental Chemistry |
A compositional domain in genetics is a region of DNA with a distinct guanine (G) and cytosine (C) G-C and C-G content (collectively GC content). The homogeneity of compositional domains is compared to that of the chromosome on which they reside. As such, compositional domains can be homogeneous or nonhomogeneous domains. Compositionally homogeneous domains that are sufficiently long (= 300 kb) are termed isochores or isochoric domains.
The compositional domain model was proposed as an alternative to the isochoric model. The isochore model was proposed by Bernardi and colleagues to explain the observed non-uniformity of genomic fragments in the genome. However, recent sequencing of complete genomic data refuted the isochoric model. Its main predictions were:
* GC content of the third codon position (GC3) of protein coding genes is correlated with the GC content of the isochores embedding the corresponding genes. This prediction was found to be incorrect. GC3 could not predict the GC content of nearby sequences.
* The genome organization of warm-blooded vertebrates is a mosaic of isochores. This prediction was rejected by many studies that used the complete human genome data.
* The genome organization of cold-blooded vertebrates is characterized by low GC content levels and lower compositional heterogeneity. This prediction was disproved by finding high and low GC content domains in fish genomes.
The compositional domain model describes the genome as a mosaic of short and long homogeneous and nonhomogeneous domains. The composition and organization of the domains were shaped by different evolutionary processes that either fused or broke down the domains. This genomic organization model was confirmed in many new genomic studies of cow, honeybee, sea urchin, body louse, Nasonia, beetle, and ant genomes. The human genome was described as consisting of a mixture of compositionally nonhomogeneous domains with numerous short compositionally homogeneous domains and relatively few long ones. | 1 | Applied and Interdisciplinary Chemistry |
Methyl isocyanate (MIC) is highly flammable. MDI and TDI are much less flammable. Flammability of materials is a consideration in furniture design. The specific flammability hazard is noted on the safety data sheet (SDS) for specific isocyanates. | 0 | Theoretical and Fundamental Chemistry |
In order to isolate clones that contain regions of interest from a library, the library must first be screened. One method of screening is hybridization. Each transformed host cell of a library will contain only one vector with one insert of DNA. The whole library can be plated onto a filter over media. The filter and colonies are prepared for hybridization and then labeled with a probe. The target DNA- insert of interest- can be identified by detection such as autoradiography because of the hybridization with the probe as seen below.
Another method of screening is with polymerase chain reaction (PCR). Some libraries are stored as pools of clones and screening by PCR is an efficient way to identify pools containing specific clones. | 1 | Applied and Interdisciplinary Chemistry |
Hox genes play a massive role in some amphibians and reptiles in their ability to regenerate lost limbs, especially HoxA and HoxD genes.
If the processes involved in forming new tissue can be reverse-engineered into humans, it may be possible to heal injuries of the spinal cord or brain, repair damaged organs and reduce scarring and fibrosis after surgery. Despite the large conservation of the Hox genes through evolution, mammals and humans specifically cannot regenerate any of their limbs. This raises a question as to why humans which also possess an analog to these genes cannot regrow and regenerate limbs. Beside the lack of specific growth factor, studies have shown that something as small as base pair differences between amphibian and human Hox analogs play a crucial role in human inability to reproduce limbs. Undifferentiated stem cells and the ability to have polarity in tissues is vital to this process. | 1 | Applied and Interdisciplinary Chemistry |
The isoelectric points (IEP) of metal oxide ceramics are used extensively in material science in various aqueous processing steps (synthesis, modification, etc.). In the absence of chemisorbed or physisorbed species particle surfaces in aqueous suspension are generally assumed to be covered with surface hydroxyl species, M-OH (where M is a metal such as Al, Si, etc.). At pH values above the IEP, the predominant surface species is M-O, while at pH values below the IEP, M-OH species predominate. Some approximate values of common ceramics are listed below:
Note: The following list gives the isoelectric point at 25 °C for selected materials in water. The exact value can vary widely, depending on material factors such as purity and phase as well as physical parameters such as temperature. Moreover, the precise measurement of isoelectric points can be difficult, thus many sources often cite differing values for isoelectric points of these materials.
Mixed oxides may exhibit isoelectric point values that are intermediate to those of the corresponding pure oxides. For example, a synthetically prepared amorphous aluminosilicate (AlO-SiO) was initially measured as having IEP of 4.5 (the electrokinetic behavior of the surface was dominated by surface Si-OH species, thus explaining the relatively low IEP value). Significantly higher IEP values (pH 6 to 8) have been reported for 3AlO-2SiO by others. Similarly, also IEP of barium titanate, BaTiO was reported in the range 5–6 while others got a value of 3. Mixtures of titania (TiO) and zirconia (ZrO) were studied and found to have an isoelectric point between 5.3–6.9, varying non-linearly with %(ZrO). The surface charge of the mixed oxides was correlated with acidity. Greater titania content led to increased Lewis acidity, whereas zirconia-rich oxides displayed Br::onsted acidity. The different types of acidities produced differences in ion adsorption rates and capacities. | 0 | Theoretical and Fundamental Chemistry |
Reversible solid oxide cells are receiving increased attention as energy storage solutions for the weekly or the monthly scale. Other technologies for large scale electrical storage such as pumped-storage hydroelectricity and compressed air energy storage are characterized by geographical limitations. On the other hand, Li-ion batteries suffer from limited discharge capabilities. In this regard, hydrogen storage is a promising alternative, since the produced fuel can be compressed and stored for months. Among all hydrogen technologies, rSOCs are definitely the best candidates for producing and converting back hydrogen into electricity. Due to their high operating temperature, they are characterized by higher efficiency, compared to technologies like PEM fuel cells or PEM electrolyzers. Moreover, the possibility to operate both the fuel oxidation and the electrolysis on the same device is beneficial on the capacity factor of the system, helping at reducing its specific investment cost. | 0 | Theoretical and Fundamental Chemistry |
The glyoxalase system is a set of enzymes that carry out the detoxification of methylglyoxal and the other reactive aldehydes that are produced as a normal part of metabolism. This system has been studied in both bacteria and eukaryotes. This detoxification is accomplished by the sequential action of two thiol-dependent enzymes; firstly glyoxalase І, which catalyzes the isomerization of the spontaneously formed hemithioacetal adduct between glutathione and 2-oxoaldehydes (such as methylglyoxal) into S-2-hydroxyacylglutathione. Secondly, glyoxalase ІІ hydrolyses these thiolesters and in the case of methylglyoxal catabolism, produces D-lactate and GSH from S-D-lactoyl-glutathione.
This system shows many of the typical features of the enzymes that dispose of endogenous toxins. Firstly, in contrast to the amazing substrate range of many of the enzymes involved in xenobiotic metabolism, it shows a narrow substrate specificity. Secondly, intracellular thiols are required as part of its enzymatic mechanism and thirdly, the system acts to recycle reactive metabolites back to a form which may be useful to cellular metabolism. | 1 | Applied and Interdisciplinary Chemistry |
Chitosan is a linear polysaccharide containing linked chitin-derived residues and is widely studied as a biomaterial due to its high compatibility with numerous proteins in the body. Chitosan is cationic and thus electrostatically reacts with numerous proteoglycans, anionic GAGs, and other molecules possessing a negative charge. Since many cytokines and growth factors are linked to GAG, scaffolds with the chitosan-GAG complexes are able to retain these proteins secreted by the adhered cells. Another quality of chitosan that gives it good biomaterial potential is its high charge density in solutions. This allows chitosan to form ionic complexes with many water-soluble anionic polymers, expanding the range of proteins that are able to bind to it and thus expanding its possible uses.
Table 1: Structures, target tissues, and application cell types of chitosan-based scaffolds | 1 | Applied and Interdisciplinary Chemistry |
The atoms in a gas which are emitting radiation will have a distribution of velocities. Each photon emitted will be "red"- or "blue"-shifted by the Doppler effect depending on the velocity of the atom relative to the observer. The higher the temperature of the gas, the wider the distribution of velocities in the gas. Since the spectral line is a combination of all of the emitted radiation, the higher the temperature of the gas, the broader the spectral line emitted from that gas. This broadening effect is described by a Gaussian profile and there is no associated shift. | 0 | Theoretical and Fundamental Chemistry |
The USBM index is theoretically unbounded and can vary from negative infinity to positive infinity. Since other wettability indices such as Amott-Harvey, Lak wettability index and modified Lak are bounded in the range of -1 to 1, Abouzar Mirzaei-Paiaman highlighted the bounded form of USBM (called USBM*) as a replacement of the traditional USBM as
USBM* varies from -1 to 1 for strongly oil-wet and strongly water-wet rocks, respectively. | 0 | Theoretical and Fundamental Chemistry |
A monolayer is a single, closely packed layer of entities, commonly atoms or molecules.
Monolayers can also be made out of cells.
Self-assembled monolayers form spontaneously on surfaces.
Monolayers of layered crystals like graphene and molybdenum disulfide are generally called 2D materials. | 0 | Theoretical and Fundamental Chemistry |
Principally retrofitting describes the measures taken in the manufacturing industry to allow new or updated parts to be fitted to old or outdated assemblies (like blades to wind turbines).
Retrofitting parts are necessary for manufacture when the design of a large assembly is changed or revised. If, after the changes have been implemented, a customer (with an old version of the product) wishes to purchase a replacement part, then retrofit parts and assembling techniques will have to be used so that the revised parts will fit suitably onto the older assembly.
Retrofitting is an important process used for valves and actuators to ensure optimal operation of an industrial plant. One example is retrofitting a 3-way valve into a 2-way valve, which results in closing one of the three openings to continue using the valve for certain industrial systems.
Retrofitting can improve a machine or system's overall functionality by using advanced and updated equipment and technology—such as integrating Human Machine Interfaces into older factories. | 1 | Applied and Interdisciplinary Chemistry |
Fatty acyl-CoA esters are fatty acid derivatives formed of one fatty acid, a 3'-phospho-AMP linked to phosphorylated pantothenic acid (vitamin B) and cysteamine.
Long-chain acyl-CoA esters are substrates for a number of important enzymatic reactions and play a central role in the regulation of metabolism as allosteric regulators of several enzymes. To participate in specific metabolic processes, fatty acids must first be activated by being joined in thioester linkage (R-CO-SCoA) to the -SH group of coenzyme A, where R is a fatty carbon chain. The thioester bond is a high energy bond.
The activation reaction normally occurs in the endoplasmic reticulum or the outer mitochondrial membrane. This is an ATP-requiring reaction (fatty acyl-CoA synthase), yielding AMP and pyrophosphate (PPi). Different enzymes are specific for fatty acids of different chain length.
Then, the acyl CoA esters are transported in mitochondria. They are converted to fatty acyl carnitine by carnitine acyltransferase I, an enzyme of the inner leaflet of the outer mitochondrial membrane. Fatty acyl carnitine is then transported by an antiport in exchange for free carnitine to the inner surface of the inner mitochondrial membrane. There carnitine acyltransferase II reverses the process, producing fatty acyl-CoA and carnitine. This shuttle mechanism is required only for longer chain fatty acids.
Once inside the mitochondrial matrix, the fatty acyl-CoA derivatives are degraded by a series of reactions that release acetyl-CoA and leads to the production of NADH and FADH2. There are four steps in fatty acid oxidation pathway; oxidation, hydration, oxidation, and thiolysis. It requires 7 rounds of this pathway to degrade palmitate (a C16 fatty acid). | 1 | Applied and Interdisciplinary Chemistry |
While most failures in practice have been through fast failure, there is experimental evidence that hydrogen also affects the fatigue properties of steels. This is entirely expected given the nature of the embrittlement mechanisms proposed for fast fracture. In general hydrogen embrittlement has a strong effect on high-stress, low-cycle fatigue and very little effect on high-cycle fatigue. | 0 | Theoretical and Fundamental Chemistry |
The solubility of a gas in a liquid increases with increasing gas pressure. When the external pressure is reduced, the excess gas comes out of solution.
Fizzy drinks are made by subjecting the liquid to carbon dioxide, under pressure. In champagne the CO is produced naturally in the final stage of fermentation. When the bottle or can is opened some gas is released in the form of bubbles.
Release of gas from supersaturated tissues can cause an underwater diver to suffer from decompression sickness (a.k.a. the bends) when returning to the surface. This can be fatal if the released gas obstructs critical blood supplies causing ischaemia in vital tissues.
Dissolved gases can be released during oil exploration when a strike is made. This occurs because the oil in oil-bearing rock is under considerable pressure from the over-lying rock, allowing the oil to be supersaturated with respect to dissolved gases. | 0 | Theoretical and Fundamental Chemistry |
REMS technology performance has been evaluated through multicentre clinical studies. The work of Di Paola et al. has investigated precision and diagnostic accuracy of REMS in comparison with DXA on a sample of 2000 patients. A very high correlation has been observed between the T-Score values obtained by both technologies (Pearson correlation coefficient > 0.93; Cohen’s Kappa equals to 0.82 for lumbar spine and 0.79 for femoral neck) as well as a very low average BMD difference between the two techniques (mean ± 2 standard deviations): −0.004±0.088 g/cm for lumbar spine and −0.006±0.076 g/cm for femoral neck. Furthermore, specificity and sensitivity of REMS in the discrimination between osteoporotic and non-osteoporotic patients has been evaluated: sensitivity and specificity exceed 91% for both skeletal sites. Additional outcomes of this study are the values of precision and repeatability of REMS estimates, assessed using the Root Mean Square Coefficient of Variation (CV-RMS): precision has been evaluated as being 0.38% for lumbar spine and 0.32% for femoral neck, whereas the Least Significant Change (LSC) resulted in 1.05% and 0.88%, respectively. Finally, inter-operator repeatability has been calculated, which has resulted in 0.54% for lumbar spine and 0.48% for femoral neck. These values are significantly lower than those reported about DXA in the scientific literature and offer concrete advantages from the point of view of short-term follow-up of patients undergoing therapeutic treatments. | 0 | Theoretical and Fundamental Chemistry |
In organic chemistry, thioenols (also known as alkenethiols) are alkenes with a thiol group () affixed to one of the carbon atoms composing the double bond (i.e. ). They are the sulfur analogs of enols (hence the thio- prefix). Alkenes with a thiol group on both atoms of the double bond are called enedithiols. Deprotonated anions of thioenols are called thioenolates.
These structures exhibit tautomerism to give thioketones or thioaldehydes, analogous to keto–enol tautomerism of carbonyl structures. | 0 | Theoretical and Fundamental Chemistry |
In combustion, Zeldovich–Liñán model is a two-step reaction model for the combustion processes, named after Yakov Borisovich Zeldovich and Amable Liñán. The model includes a chain-branching and a chain-breaking (or radical recombination) reaction. The model was first introduced by Zel'dovich in 1948 and later analysed by Liñán using activation energy asymptotics in 1971. The mechanism reads as
where is the fuel, is an intermediate radical, is the third body and is the product. The first reaction is the chain-branching reaction, which is considered to be auto-catalytic (consumes no heat or releases no heat), with very large activation energy and the second reaction is the chain-breaking (or radical-recombination) reaction, where all of the heat in the combustion is released, with almost negligible activation energy. | 0 | Theoretical and Fundamental Chemistry |
In 1987 Pedro Cuatrecasas and Meir Wilchek were awarded the Wolf Prize in Medicine for the invention and development of affinity chromatography and its applications to biomedical sciences. | 1 | Applied and Interdisciplinary Chemistry |
Blood test results should always be interpreted using the reference ranges provided by the laboratory that performed the results. Example reference ranges are listed below. | 0 | Theoretical and Fundamental Chemistry |
Humic substances in soils and sediments can be divided into three main fractions: humic acids, fulvic acids, and humin.
Humic and fulvic acids are extracted from soil and other solid phase sources into a strongly basic aqueous solution of sodium hydroxide or potassium hydroxide.
*Humic acids are precipitated from this solution by adjusting the pH to 1 with hydrochloric acid.
*The alcohol-soluble portion of humic fraction is, in general, named ulmic acid.
** So-called "gray humic acids" (GHA) are soluble in low-ionic-strength alkaline media.
** "Brown humic acids" (BHA) are soluble in alkaline conditions independent of ionic strength
* Fulvic acids is left in solution at pH 1. They remain soluble independent of pH and ionic strength.
* Humin is insoluble in dilute alkali.
The International Humic Substances Society (IHSS) advocates the use of standard laboratory methods for preparation of humic and fulvic acids. Humic substances are extracted from soil and other solid sources using NaOH, the humic acids are then precipitated at pH 1, and the soluble fraction is treated on a resin column to separate fulvic acid components from other acid soluble compounds. Humic acid plus fulvic acid are extracted from natural waters using a resin column after microfiltration and acidification to pH 2. The humic materials are eluted from the column with NaOH and humic acid is precipitated at pH 1. After adjusting the pH to 2 the fulvic acid is separated from other acid soluble compounds using a resin column as with solid phase sources. An analytical method for quantifying humic acid and fulvic acid in commercial ores and products, has been developed based on the IHSS humic acid and fulvic acid preparation methods,
Extracted humic acid not a single acid; rather, it is a complex mixture of many different acids containing carboxyl and phenolate groups so that the mixture behaves functionally as a dibasic acid or, occasionally, as a tribasic acid. Commercial humic acid used to amend soil is manufactured using these same well established procedures. Humic acids can form complexes with ions that are commonly found in the environment creating humic colloids.
As a nutrition supplement, fulvic acid can be found in a liquid form as a component of mineral colloids. Fulvic acids are poly-electrolytes and are unique colloids that diffuse easily through membranes, whereas all other colloids do not.
A sequential chemical fractionation called Humeomics can be used to isolate more homogeneous humic fractions and determine their molecular structures by advanced spectroscopic and chromatographic methods. Substances identified in humic extracts and directly in soil include mono-, di-, and tri-hydroxycarboxylic acids, fatty acids, dicarboxylic acids, linear alcohols, phenolic acids, terpenoids, carbohydrates, and amino acids. | 0 | Theoretical and Fundamental Chemistry |
Magnum opus – great work of alchemy consisting of:
*Nigredo
*Albedo
*Citrinitas (sometimes excluded)
*Rubedo
Alchemists also engaged in practical and symbolic processes including:
*Calcination
*Ceration
*Cohobation
*Congelation
*Digestion
*Distillation
*Fermentation
*Filtration
*Fixation
*Multiplication
*Projection
*Solution
*Sublimation | 1 | Applied and Interdisciplinary Chemistry |
Bioactive metallic glass is a subset of bioactive glass, wherein the bulk material is composed of a metal-glass substrate and is coated with bioactive glass in order to make the material bioactive. The reasoning behind the introduction of the metallic base is to create a less brittle, stronger material that will be permanently implanted within the body. Metallic glasses tout lower Youngs Moduli and higher elastic limits than bioactive glass, and as such, will allow for more deformation of the material before fracture occurs. This is highly desirable, as a permanent implant would need to avoid shattering within the patients body. Common materials which compose the metallic bulk include Zr and Ti, whereas some examples of the few key metals that shouldn't be used as bulk materials are Al, Be, and Ni. | 0 | Theoretical and Fundamental Chemistry |
In 2015, scientists at the Z Pulsed Power Facility announced the creation of metallic deuterium using dense liquid deuterium, an electrical insulator-to-conductor transition associated with an increase in optical reflectivity. | 0 | Theoretical and Fundamental Chemistry |
Organic ionic plastic crystals – are a type organic salts exhibiting mesophases (i.e. a state of matter intermediate between liquid and solid), in which mobile ions are orientationally or rotationally disordered while their centers are located at the ordered sites in the crystal structure. They have various forms of disorder due to one or more solid–solid phase transitions below the melting point and have therefore plastic properties and good mechanical flexibility as well as improved electrode|electrolyte interfacial contact. In particular, protic organic ionic plastic crystals (POIPCs), which are solid protic organic salts formed by proton transfer from a Brønsted acid to a Brønsted base and in essence are protic ionic liquids in the molten state, have found to be promising solid-state proton conductors for fuel cells. Examples include 1,2,4-triazolium perfluorobutanesulfonate and imidazolium methanesulfonate. | 0 | Theoretical and Fundamental Chemistry |
* Biochemical engineering
* Biomedical engineering
* Biotechnology
* Ceramics
* Chemical process modeling
* Chemical Technologist
* Chemical reactor
* Chemical reaction engineering
* Distillation Design
* Electrochemistry
* Fluid dynamics
* Food engineering
* Heat transfer
* Mass transfer
* Materials science
* Microfluidics
* Nanotechnology
* Natural environment
* Plastics engineering
* Polymer engineering
* Process control
* Process design (chemical engineering)
* Separation processes (see also: separation of mixture)
** Crystallization processes
** Distillation processes
** Membrane processes
* Semiconductors
* Thermodynamics
* Transport phenomena
* Unit operations
* Unit Operations of Chemical Engineering | 1 | Applied and Interdisciplinary Chemistry |
The rationale for IORT is to deliver a high dose of radiation precisely to the targeted area with minimal exposure of surrounding tissues which are displaced or shielded during the IORT. Conventional radiation techniques such as external beam radiotherapy (EBRT) following surgical removal of the tumor have several drawbacks: The tumor bed where the highest dose should be applied is frequently missed due to the complex localization of the wound cavity even when modern radiotherapy planning is used. Additionally, the usual delay between the surgical removal of the tumor and EBRT may allow a repopulation of the tumor cells. These potentially harmful effects can be avoided by delivering the radiation more precisely to the targeted tissues leading to immediate sterilization of residual tumor cells. Another aspect is that wound fluid has a stimulating effect on tumor cells. IORT was found to inhibit the stimulating effects of wound fluid. | 0 | Theoretical and Fundamental Chemistry |
In coordination chemistry and organometallic chemistry, transition metal imido complexes is a coordination compound containing an imido ligand. Imido ligands can be terminal or bridging ligands. The parent imido ligand has the formula NH, but most imido ligands have alkyl or aryl groups in place of H. The imido ligand is generally viewed as a dianion, akin to oxide. | 0 | Theoretical and Fundamental Chemistry |
Chan King-ming earned his Bachelor of Science and Master of Philosophy degrees at the Chinese University of Hong Kong, and his doctoral degree from Memorial University of Newfoundland in St. John's, Newfoundland, Canada.
He is now director of the Environmental Science Program at the Chinese University of Hong Kong. He teaches many different courses including Current Environmental Issues, Biochemical Toxicology and Introduction to Environmental Science in the Environmental Science Program and Molecular Endocrinology in the Biochemistry Programme. Trained as a molecular biologist for his PhD and post-doctoral research, Professor Chan's research interests include gene regulation, aquatic toxicology, marine biotechnology and environmental biochemistry and environmental policy. Prof. Chan is also chairman of CUTA (Chinese University Teachers Association), trustee of Shaw College Board of trustees, Member of Assembly of Fellows, Shaw College, and warden of Hostel 2, Shaw College. | 1 | Applied and Interdisciplinary Chemistry |
Kowalski was the founding editor of the Journal of Chemometics, the first issue of which came out in January 1987. The editorial of the first issue, written by Kowalski, Steven Brown and Bernard Vandeginst, explains that after 10 years of the founding of the field of chemometrics and 20 years of researchers actually doing chemometrics and having their publications "widely distributed through the literature," it was time for a journal "to bring together papers on how chemists use mathematics and statistics in their work in novel ways and also on potentially new tools that chemists may find useful in the future." After his death the journal published a special issue in his honor in May 2014. It also established the annual Kowalski Prize for the best theoretical and applied papers published in the journal in the two preceding years. | 0 | Theoretical and Fundamental Chemistry |
Based on the tetrahedral units, FK crystallographic structures are classified into low and high polyhedral groups denoted by their coordination numbers (CN) referring to the number of atom centering the polyhedron.
Some atoms have an icosahedral structure with low coordination, labeled CN12. Some others have higher coordination numbers of 14, 15 and 16, labeled CN14, CN15, and CN16, respectively. These atoms with higher coordination numbers form uninterrupted networks connected along the directions where the five-fold icosahedral symmetry is replaced by six-fold local symmetry. The sites of 12-coordination are called minor sites and those with more than 12-fold coordination are major sites. | 1 | Applied and Interdisciplinary Chemistry |
These are extremely light-sensitive vacuum tubes with a coated photocathode inside the envelope. The photo cathode contains combinations of materials such as cesium, rubidium, and antimony specially selected to provide a low work function, so when illuminated even by very low levels of light, the photocathode readily releases electrons. By means of a series of electrodes (dynodes) at ever-higher potentials, these electrons are accelerated and substantially increased in number through secondary emission to provide a readily detectable output current. Photomultipliers are still commonly used wherever low levels of light must be detected. | 0 | Theoretical and Fundamental Chemistry |
If one assumes infinite shunt resistance, the characteristic equation can be solved for V:
Thus, an increase in I produces a reduction in V proportional to the inverse of the logarithm of the increase. This explains mathematically the reason for the reduction in V that accompanies increases in temperature described above. The effect of reverse saturation current on the I-V curve of a crystalline silicon solar cell are shown in the figure to the right. Physically, reverse saturation current is a measure of the "leakage" of carriers across the p-n junction in reverse bias. This leakage is a result of carrier recombination in the neutral regions on either side of the junction. | 0 | Theoretical and Fundamental Chemistry |
Polymer properties depend of their structure and they are divided into classes according to their physical bases. Many physical and chemical properties describe how a polymer behaves as a continuous macroscopic material. They are classified as bulk properties, or intensive properties according to thermodynamics. | 0 | Theoretical and Fundamental Chemistry |
Diazirines are often used as photoreactive crosslinking reagents, as the reactive carbenes they form upon irradiation with UV light can insert into C-H, N-H, and O-H bonds. This results in proximity dependent labeling of other species with the diazirine containing compound.
Diazirines are often preferred to other photoreactive crosslinking reagents due to their smaller size, longer irradiation wavelength, short period of irradiation required, and stability in the presence of various nucleophiles, and in both acidic and basic conditions. Benzophenones, which form reactive triplet carbonyl species upon irradiation, often require long periods of irradiation which can result in non-specific labeling, and moreover are often inert to various polar solvents. Aryl azides require a low wavelength of irradiation, which can damage the biological macromolecules under investigation. | 0 | Theoretical and Fundamental Chemistry |
A 1971 study published by the Harvard Medical School identified methylglyoxal, a form of glycerol, as a product of lethal synthesis in a specific E.coli mutant. In E.coli, the synthesis of triose phosphate from glycerol is a reaction regulated by the synthesis rate of glycerol kinase and by feedback inhibition by fructose-1,6-bisphosphate. The study demonstrated that, in E.coli mutants that had lost both control mechanisms, glycerol kinase no longer reacted to feedback regulation and instead produced the cytotoxic methylglyoxal. A more recent review of research done on methylglyoxal metabolism concluded that the compound's cytotoxic nature is dependent on its ability to form advanced glycation end products (AGEs). These compounds, which are thought to be factors in ageing and in the progression of degenerative diseases, have been shown to hinder the functions of the proteins they target. | 1 | Applied and Interdisciplinary Chemistry |
Phosgene oxime can be prepared by reduction of chloropicrin using a combination of tin metal and hydrochloric acid as the source of the active hydrogen reducing agent:
The observation of a transient violet color in the reaction suggests intermediate formation of trichloronitrosomethane (ClCNO). Early preparations, using stannous chloride as the reductant, also started with chloropicrin.
The compound is electrophilic and thus sensitive to nucleophiles, including bases, which destroy it:
Phosgene oxime has been used to prepare heterocycles that contain N-O bonds, such as isoxazoles.
Dehydrohalogenation upon contact with mercuric oxide generates chlorine fulminate, a reactive nitrile oxide: | 1 | Applied and Interdisciplinary Chemistry |
Small molecule sensors are an effective way to detect the presence of metal ions in solution. Although many types exist, most small molecule sensors comprise a subunit that selectively binds to a metal that in turn induces a change in a fluorescent subunit. This change can be observed in the small molecule sensor's spectrum, which can be monitored using a detection system such as a microscope or a photodiode. Different probes exist for a variety of applications, each with different dissociation constants with respect to a particular metal, different fluorescent properties, and sensitivities. They show great promise as a way to probe biological processes by monitoring metal ions at low concentrations in biological systems. Since they are by definition small and often capable of entering biological systems, they are conducive to many applications for which other more traditional bio-sensing are less effective or not suitable. | 0 | Theoretical and Fundamental Chemistry |
Gestation can predispose for certain digestive disorders. Gestational diabetes can develop in the mother as a result of pregnancy and while this often presents with few symptoms it can lead to pre-eclampsia. | 1 | Applied and Interdisciplinary Chemistry |
Anodizing was first used on an industrial scale in 1923 to protect Duralumin seaplane parts from corrosion. This early chromic acid–based process was called the Bengough–Stuart process and was documented in British defence specification DEF STAN 03-24/3. It is still used today despite its legacy requirements for a complicated voltage cycle now known to be unnecessary. Variations of this process soon evolved, and the first sulfuric acid anodizing process was patented by Gower and O'Brien in 1927. Sulfuric acid soon became and remains the most common anodizing electrolyte.
Oxalic acid anodizing was first patented in Japan in 1923 and later widely used in Germany, particularly for architectural applications. Anodized aluminium extrusion was a popular architectural material in the 1960s and 1970s, but has since been displaced by cheaper plastics and powder coating. The phosphoric acid processes are the most recent major development, so far only used as pretreatments for adhesives or organic paints. A wide variety of proprietary and increasingly complex variations of all these anodizing processes continue to be developed by industry, so the growing trend in military and industrial standards is to classify by coating properties rather than by process chemistry. | 1 | Applied and Interdisciplinary Chemistry |
In 1980, McPhee traveled with his daughter on a canoe trip on the Atchafalaya River due to her fascination with the novelist Walker Percy. He had conversations with natives about the efforts made by the Army Corps of Engineers in monitoring riverflow in the area. In Vicksburg, Mississippi, a man recommended to McPhee that he research the efforts being undergone to control the debris sliding down from mountains into Los Angeles. When he visited California, a geologist informed him about lava in Iceland.
The books title is derived from a sign on the engineering building at the University of Wyoming. Though he believes nature will win, "my book is not an editorial," McPhee said. "It is a description of people defying nature. They may have no choice." Like all of McPhees books, The Control of Nature started out as an outline that he proceeded to fill in. | 1 | Applied and Interdisciplinary Chemistry |
The role of angiogenesis in the support of myeloma was first discovered by Vacca in 1994. They discovered increased bone marrow angiogenesis correlates with myeloma growth and supporting stromal cells are a significant source for angiogenic molecules in myeloma. This is believed to be a main component of the mechanism in vivo by which thalidomide inhibits multiple myeloma.
Additionally, inflammatory responses within the bone marrow are believed to foster many hematological diseases. The secretion of IL-6 by bone marrow stromal cells (BMSC) and the secretion of the adhesion molecules VCAM-1, ICAM-1 and LFA, is induced in the presence of TNF-α and the adhesion of MM cells to BMSC. In vitro proliferation of MM cell lines and inhibition of Fas-mediated apoptosis is promoted by IL-6. Thalidomide and its analogs directly decrease the up-regulation of IL-6 and indirectly through TNF-α, thereby reducing the secretion of adhesion molecules leading to fewer MM cells adhering to BMSC. Osteoclasts become highly active during MM, leading to bone resorption and secretion of various MM survival factors. They decrease the levels of adhesion molecules paramount to osteoclast activation, decrease the formation of the cells that form osteoclasts and downregulate cathepsin K, an important cysteine protease expressed in osteoclasts. | 1 | Applied and Interdisciplinary Chemistry |
Early second generation cephalosporins are very similar in basic structure to the first generation. Loracarbef however does not have the normal dihydrothiazine ring but is a carbacephem that has a carbon atom in the ring instead of a sulfur atom making it a tetrahydropyridine ring. This chemical property gives loracarbef better stability in plasma while retaining oral absorption characteristics and affinity for binding to PBP. The 7-phenyl-glycine makes it orally available and the chlorine at position C-3 makes it as active as cefaclor. An important structural change in the development of second generation cephalosporins was the introduction of an α-iminomethoxy group to the C-7 side chain. This gave an increased resistance to β-lactamases due to stereochemical blocking of the beta-lactam ring. Cefuroxime was the first cephalosporin to incorporate this side chain. Another very important group in the second generation is the aminothiazole ring to the C-3 side chain. This development drastically increased binding affinity to PBP and increased antimicrobial activity. The aminothiazole ring can be seen in the structure of cefotiam. | 1 | Applied and Interdisciplinary Chemistry |
Tentative evidence in Alzheimer's disease showed that lithium may slow progression. It has been studied for its potential use in the treatment of amyotrophic lateral sclerosis (ALS), but a study showed lithium had no effect on ALS outcomes. | 1 | Applied and Interdisciplinary Chemistry |
Many compounds and complexes adopt bitetrahedral structures. In this motif, the two tetrahedra share a common edge. The inorganic polymer silicon disulfide features an infinite chain of edge-shared tetrahedra. In a completely saturated hydrocarbon system, bitetrahedral molecule CH has been proposed as a candidate for the molecule with the shortest possible carbon-carbon single bond. | 0 | Theoretical and Fundamental Chemistry |
In typical engineering applications, there will be a set of given or known quantities. The acceleration of gravity and the kinematic viscosity of the fluid are known, as are the diameter of the pipe and its roughness height . If as well the head loss per unit length is a known quantity, then the friction factor can be calculated directly from the chosen fitting function. Solving the Darcy–Weisbach equation for ,
we can now express :
Expressing the roughness Reynolds number ,
we have the two parameters needed to substitute into the Colebrook–White relation, or any other function, for the friction factor , the flow velocity , and the volumetric flow rate . | 1 | Applied and Interdisciplinary Chemistry |
Robert Burns Woodward (April 10, 1917 – July 8, 1979) was an American organic chemist. He is considered by many to be the preeminent synthetic organic chemist of the twentieth century, having made many key contributions to the subject, especially in the synthesis of complex natural products and the determination of their molecular structure. He worked closely with Roald Hoffmann on theoretical studies of chemical reactions. He was awarded the Nobel Prize in Chemistry in 1965. | 0 | Theoretical and Fundamental Chemistry |
A common method of freezing lesions is by using liquid nitrogen as the cryogen. The liquid nitrogen may be applied to lesions using a variety of methods; such as dipping a cotton or synthetic material tipped applicator in liquid nitrogen and then directly applying the cryogen onto the lesion. The liquid nitrogen can also be sprayed onto the lesion using a spray canister. The spray canister may utilize a variety of nozzles for different spray patterns. A cryoprobe, which is a metal applicator that has been cooled using liquid nitrogen, can also be directly applied onto lesions. | 1 | Applied and Interdisciplinary Chemistry |
In 1989, Alan Mackay suggested that if chemical synthesis could be used to make L-protein and D-protein enantiomers, it would enable the use of racemic mixtures to crystallize proteins in centrosymmetric space groups. He stated that, because in the X-ray diffraction data obtained from a centrosymmetric crystal the off-diagonal phases would cancel giving phases that differ by 180 degrees, this would facilitate solving the phase problem in protein structure determination through X-ray crystallography.
In 1993, Laura Zawadzke and Jeremy Berg first used the small (45 amino acids) protein rubredoxin to synthesize it in racemic form. This was done since the structural determination would potentially be easier and more robust by using diffraction data from a centrosymmetric crystal, which requires growth from a racemic mixture. By having a centre of symmetry formed by the racemic protein pairs, the steps of phasing diffraction in data analysis would be further simplified. As mentioned above, in 1995 Stephanie Wukovitz and Todd Yeates had developed a mathematical theory to explain why protein molecules tend to crystallize more frequently in certain space groups than in others; they predicted that the most favored protein space group would be P1<bar>, and predicted that globular proteins would crystallize more easily as racemates, from a racemic protein mixture. | 0 | Theoretical and Fundamental Chemistry |
After World War II ended in 1945, Bruno Tesch and Karl Weinbacher of Tesch & Stabenow were tried in a British military court and executed for knowingly providing Zyklon B to the SS for use on humans. Gerhard Peters, who served as principal operating officer of Degesch and Heli and also held posts in the Nazi government, served two years and eight months in prison as an accessory before being released due to amendments to the penal code.
Use of hydrogen cyanide as a pesticide or cleaner has been banned or restricted in some countries. Most hydrogen cyanide is used in industrial processes, made by companies in Germany, Japan, the Netherlands and the US. Degesch resumed production of Zyklon B after the war. The product was sold as Cyanosil in Germany and Zyklon in other countries. It was still produced as of 2008. Degussa sold Degesch to Detia-Freyberg GmbH in 1986. The company is now called Detia-Degesch. Up until around 2015, a fumigation product similar to Zyklon B was in production by Lučební závody Draslovka of the Czech Republic, under the trade name Uragan D2. Uragan means "hurricane" or "cyclone" in Czech.
Subsequent use of the word "Zyklon" in trade names has prompted angry reactions in English-speaking countries. The name "Zyklon" on portable roller coasters made since 1965 by Pinfari provoked protests among Jewish groups in the U.S. in 1993 and 1999. In 2002, British sportswear and football equipment supplier Umbro issued an apology and stopped using the name "Zyklon", which had appeared since 1999 on the box for one of its trainers, after receiving complaints from the Simon Wiesenthal Center and the Beth Shalom Holocaust Centre. Also in 2002, Siemens withdrew its application for an American trademark of the word "Zyklon", which their subsidiary BSH Bosch und Siemens Hausgeräte had proposed to use for a new line of home appliances in the United States. (The firm was already using the name in Germany for one of their vacuum cleaners.) Protests were lodged by the Simon Wiesenthal Center after the trademark application was reported to BBC News Online by one of their readers. French company IPC's product names used "Cyclone" for degreasers and suffix "B" for biodegradable: "Cyclone B" was renamed ("green cap") in 2013 after protests from Jewish groups. A rabbi said the name was "horrible ignorance at best, and a Guinness record in evil and cynicism if the company did know the history of the name of its product."
Holocaust deniers claim that Zyklon B gas was not used in the gas chambers, relying for evidence on the discredited research of Fred A. Leuchter, who found low levels of Prussian blue in samples of the gas chamber walls and ceilings. Leuchter attributed its presence to general delousing of the buildings. Leuchters negative control, a sample of gasket material taken from a different camp building, had no cyanide residue. In 1999, James Roth, the chemist who had analyzed Leuchters samples, stated that the test was flawed because the material that was sent for testing included large chunks, and the chemical would only be within 10 microns of the surface. The surface that had been exposed to the chemical was not identified, and the large size of the specimens meant that any chemical present was diluted by an undeterminable amount. In 1994, the Institute for Forensic Research in Kraków re-examined Leuchter's claim, stating that formation of Prussian blue by exposure of bricks to cyanide is not a highly probable reaction. Using microdiffusion techniques, they tested 22 samples from the gas chambers and delousing chambers (as positive controls) and living quarters (as negative controls). They found cyanide residue in both the delousing chambers and the gas chambers but none in the living quarters. | 1 | Applied and Interdisciplinary Chemistry |
*Major categories of bio-compounds:
**Carbohydrates : sugar – disaccharide – polysaccharide – starch – glycogen
**Lipids : fatty acid – fats – essential oils – oils – waxes – cholesterol
**Nucleic acids : DNA – RNA – mRNA – tRNA – rRNA – codon – adenosine – cytosine – guanine – thymine – uracil
**Proteins :
***amino acid – glycine – arginine – lysine
***peptide – primary structure – secondary structure – tertiary structure – conformation – protein folding
*Chemical properties:
**molecular bond – covalent bond – ionic bond – hydrogen bond – ester – ethyl
**molecular charge – hydrophilic – hydrophobic – polar
**pH – acid – alkaline – base
**oxidation – reduction – hydrolysis
*Structural compounds:
**In cells: flagellin – peptidoglycan – myelin – actin – myosin
**In animals: chitin – keratin – collagen – silk
**In plants: cellulose – lignin – cell wall
*Enzymes and enzyme activity:
**enzyme kinetics – enzyme inhibition
**proteolysis – ubiquitin – proteasome
**kinase – dehydrogenase
*Membranes : fluid mosaic model – diffusion – osmosis
**phospholipids – glycolipid – glycocalyx – antigen – isoprene
**ion channel – proton pump – electron transport – ion gradient – antiporter – symporter – quinone – riboflavin
*Energy pathways :
**pigments : chlorophyll – carotenoids – xanthophyll – cytochrome – phycobilin – bacteriorhodopsin – hemoglobin – myoglobin – absorption spectrum – action spectrum – fluorescence
**Photosynthesis : light reaction – dark reaction
**Fermentation : Acetyl-CoA – lactic acid
**Cellular respiration : Adenosine triphosphate (ATP) – NADH – pyruvate – oxalate – citrate
**Chemosynthesis
*Regulation
**hormones : auxin
**signal transduction – growth factor – transcription factor – protein kinase – SH3 domain
**Malfunctions : tumor – oncogene – tumor suppressor gene
**Receptors : Integrin – transmembrane receptor – ion channel
*Techniques : electrophoresis – chromatography – mass spectrometry – x-ray diffraction – Southern blot – fractionation – Gram stain – Surface Plasmon Resonance – Microscale Thermophoresis | 1 | Applied and Interdisciplinary Chemistry |
In the cytoplasm, ferrous iron is found in a soluble, chelatable state which constitutes the labile iron pool (~0.001 mM). In this pool, iron is thought to be bound to low-mass compounds such as peptides, carboxylates and phosphates, although some might be in a free, hydrated form (aqua ions). Alternatively, iron ions might be bound to specialized proteins known as metallochaperones. Specifically, poly-r(C)-binding proteins PCBP1 and PCBP2 appear to mediate transfer of free iron to ferritin (for storage) and non-heme iron enzymes (for use in catalysis). The labile iron pool is potentially toxic due to iron's ability to generate reactive oxygen species. Iron from this pool can be taken up by mitochondria via mitoferrin to synthesize Fe-S clusters and heme groups. | 1 | Applied and Interdisciplinary Chemistry |
Although research is ongoing, treatment options are currently limited; vitamins are frequently prescribed, though the evidence for their effectiveness is limited.
Pyruvate has been proposed in 2007 as a treatment option. N-acetyl cysteine reverses many models of mitochondrial dysfunction. In the case of mood disorders, specifically bipolar disorder, it is hypothesized that N-acetyl-cysteine (NAC), acetyl-L-carnitine (ALCAR), S-adenosylmethionine (SAMe), coenzyme Q10 (CoQ10), alpha-lipoic acid (ALA), creatine monohydrate (CM), and melatonin could be potential treatment options. | 1 | Applied and Interdisciplinary Chemistry |
Nucleic acid amplification is a technique used to produce several copies of a specific segment of RNA/DNA. Amplified RNA and DNA can be used for a variety of applications, such as genotyping, sequencing, and detection of bacteria or viruses. There are two different types of amplification, non-isothermal and isothermal. Non-isothermal amplification produces multiple copies of RNA/DNA through reiterative cycling between different temperatures. Isothermal amplification produces multiple copies of RNA/DNA at a constant reaction temperature. NASBA takes single stranded RNA, anneals primers to it at 65°C, and then amplifies it at 41°C to produce multiple copies of single stranded RNA. In order for successful amplification to occur, an enzyme cocktail containing, Avian Myeloblastosis Reverse Transcriptase (AMV-RT), RNase H, and RNA polymerase is used. AMV-RT synthesizes a complementary DNA strand (cDNA) from the RNA template once the primer is annealed. RNase H then degrades the RNA template and the other primer binds to the cDNA to form double stranded DNA, which RNA polymerase uses to synthesize copies of RNA. One key aspect of NASBA is that the starting material and end product is always single stranded RNA. That being said, it can be used to amplify DNA, but the DNA must be translated into RNA in order for successful amplification to occur.
Loop-mediated isothermal amplification (LAMP) is another isothermal amplification technique. | 1 | Applied and Interdisciplinary Chemistry |
Reflectivity deviates from the other properties in that it is bidirectional in nature. In other words, this property depends on the direction of the incident of radiation as well as the direction of the reflection. Therefore, the reflected rays of a radiation spectrum incident on a real surface in a specified direction forms an irregular shape that is not easily predictable. In practice, surfaces are often assumed to reflect either in a perfectly specular or a diffuse manner. In a specular reflection, the angles of reflection and incidence are equal. In diffuse reflection, radiation is reflected equally in all directions. Reflection from smooth and polished surfaces can be assumed to be specular reflection, whereas reflection from rough surfaces approximates diffuse reflection. In radiation analysis a surface is defined as smooth if the height of the surface roughness is much smaller relative to the wavelength of the incident radiation. | 0 | Theoretical and Fundamental Chemistry |
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