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In organic chemistry, tolyl groups are functional groups related to toluene. They have the general formula , the change of the relative position of the methyl and the R substituent on the aromatic ring can generate three possible structural isomers 1,2 (ortho), 1,3 (meta), and 1,4 (para). Tolyl groups are aryl groups which are commonly found in the structure of diverse chemical compounds. They are considered nonpolar and hydrophobic groups.
The functionalization to include tolyl groups into compounds is often done by Williamson etherification, using tolyl alcohols as reagents, or by C-C coupling reactions. Tolyl sulfonates are excellent leaving groups in nucleophilic substitutions, for this reason, they are commonly generated as intermediaries to activate alcohols. To this end, 4-toluenesulfonyl chloride is reacted in the presence of a base with the corresponding alcohol. | 0 | Theoretical and Fundamental Chemistry |
; In vitro measurements
Other tests measure the antioxidant capacity of a fraction. Some make use of the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical cation, which is reactive towards most antioxidants including phenolics, thiols and vitamin C. During this reaction, the blue ABTS radical cation is converted back to its colorless neutral form. The reaction may be monitored spectrophotometrically. This assay is often referred to as the Trolox equivalent antioxidant capacity (TEAC) assay. The reactivity of the various antioxidants tested are compared to that of Trolox, which is a vitamin E analog.
Other antioxidant capacity assays that use Trolox as a standard include the diphenylpicrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), ferric reducing ability of plasma (FRAP) assays or inhibition of copper-catalyzed in vitro human low-density lipoprotein oxidation.
A cellular antioxidant activity (CAA) assay also exists. Dichlorofluorescin is a probe that is trapped within cells and is easily oxidized to fluorescent dichlorofluorescein (DCF). The method measures the ability of compounds to prevent the formation of DCF by 2,2'-Azobis(2-amidinopropane) dihydrochloride (ABAP)-generated peroxyl radicals in human hepatocarcinoma HepG2 cells.
Other methods include butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), Rancimat method (rancidification assessment of fat).
; In vivo models
Larvae of the model animal Galleria mellonella, also called waxworms, can be used to test the antioxidant effect of individual molecules using boric acid in food to induce an oxidative stress. The content of malondialdehyde, an oxidative stress indicator, and activities of the antioxidant enzymes superoxide dismutase, catalase, glutathione S-transferase and glutathione peroxidase can be monitored. A prophenoloxidase can also be recovered from the insect. | 0 | Theoretical and Fundamental Chemistry |
Tattvartha Sutra is also known in Jainism as the Moksha-shastra (Scripture describing the path of liberation). | 1 | Applied and Interdisciplinary Chemistry |
Chemically, lichenin is a mixed-linkage glucan, consisting of repeating glucose units linked by β-1,3 and β-1,4 glycosidic bonds. | 1 | Applied and Interdisciplinary Chemistry |
A partnership between IBM and Caltech was established in 2009 aiming at "DNA chips" production. A Caltech group is working on the manufacturing of these nucleic-acid-based integrated circuits. One of these chips can compute whole square roots. A compiler has been written in Perl. | 1 | Applied and Interdisciplinary Chemistry |
A consequence of Newton's second law of mechanics is the conservation of the angular momentum (or the “moment of momentum”) which is fundamental to all turbomachines. Accordingly, the change of the angular momentum is equal to the sum of the external moments. The variation of angular momentum at inlet and outlet, an external torque and friction moments due to shear stresses act on an impeller or a diffuser.
Since no pressure forces are created on cylindrical surfaces in the circumferential direction, it is possible to write: | 1 | Applied and Interdisciplinary Chemistry |
ITCH is a HECT domain–containing E3 ubiquitin ligase that is ablated in non-agouti-lethal 18H (aka Itchy) mice. Itchy mice develop a severe immunological phenotype after birth that includes hyperplasia of lymphoid and hematopoietic cells, and stomach and lung inflammation. In humans ITCH deficiency causes altered physical growth, craniofacial morphology defects, defective muscle development, and aberrant immune system function. The ITCH gene is located on chromosome 20 in humans. ITCH contains a C2 domain, proline-rich region, WW domains, HECT domain, and multiple amino acids that are phosphorylated and ubiquitinated. | 1 | Applied and Interdisciplinary Chemistry |
The term "imine" was coined in 1883 by the German chemist Albert Ladenburg.
Usually imines refer to compounds with the general formula RC=NR, as discussed below. In the older literature, imine refers to the aza-analogue of an epoxide. Thus, ethylenimine is the three-membered ring species aziridine CHNH. The relationship of imines to amines having double and single bonds can be correlated with imides and amides, as in succinimide vs acetamide.
Imines are related to ketones and aldehydes by replacement of the oxygen with an NR group. When R = H, the compound is a primary imine, when R is hydrocarbyl, the compound is a secondary imine. If this group is not a hydrogen atom, then the compound can sometimes be referred to as a Schiff base. When R is OH, the imine is called an oxime, and when R is NH the imine is called a hydrazone.
A primary imine in which C is attached to both a hydrocarbyl and a H is called a primary aldimine; a secondary imine with such groups is called a secondary aldimine. A primary imine in which C is attached to two hydrocarbyls is called a primary ketimine; a secondary imine with such groups is called a secondary ketimine.
N-Sulfinyl imines are a special class of imines having a sulfinyl group attached to the nitrogen atom. | 0 | Theoretical and Fundamental Chemistry |
In molecular biology, pertactin (PRN) is a highly immunogenic virulence factor of Bordetella pertussis, the bacterium that causes pertussis. Specifically, it is an outer membrane protein that promotes adhesion to tracheal epithelial cells. PRN is purified from Bordetella pertussis and is used for the vaccine production as one of the important components of acellular pertussis vaccine.
A large part of the N-terminus of the pertactin protein is composed of beta helix repeats. This region of the pertactin protein is secreted through the C-terminal autotransporter. The N-terminal signal sequences promotes the secretion of PRN into the periplasm through the bacterial secretion system (Sec) and consequently, the translocation into the outer membrane where it is proteolytically cleaved. The loops in the right handed β-helix of the N-terminus that protrudes out of cell surface (region R1) contains sequence repeats Gly-Gly-Xaa-Xaa-Pro and the RGD domain Arg-Gly-Asp. This RGD domain allows PRN to function as an adhesin and invasin, binding to integrins on the outer membrane of the cell. Another loop of the extending β-helix is region 2 (R2) which contains Pro-Gln-Pro (PQP) repeats towards the C-terminus. This protein’s contribution to immunity is still premature. Reports suggest that R1 and R2 are immunogenic regions, however, recent studies regarding genetic variation of those regions prove otherwise. | 1 | Applied and Interdisciplinary Chemistry |
In the process industry, chemical industry, manufacturing industry, and other commercial and industrial contexts, pipe marking is used to identify the contents, properties and flow direction of fluids in piping. It is typically carried out by marking piping through labels and color codes. Pipe marking helps personnel and fire response teams identify the correct pipes for operational, maintenance or emergency response purposes. | 1 | Applied and Interdisciplinary Chemistry |
The Emerson effect is the increase in the rate of photosynthesis after chloroplasts are exposed to light of wavelength 680 nm (deep red spectrum) and more than 680 nm (far red spectrum). When simultaneously exposed to light of both wavelengths, the rate of photosynthesis is far higher than the sum of the red light and far red light photosynthesis rates. The effect was early evidence that two photosystems, processing different wavelengths, cooperate in photosynthesis. | 0 | Theoretical and Fundamental Chemistry |
Several properties may make Glycoazodyes an environmentally friendly alternative to traditional synthetic dyes. The increased hydrophilicity of Glycoazodyes allows for the elimination of surfactants, mordants, and salts, during the dyeing process and permits the aqueous dying of a variety of textiles at moderate temperatures and pressures. The unique structure may also allow for the treatment of textile effluent through biological means. Fusarium oxysporum efficiently decolourizes the first-generation Glycoazodye 4-{N,N-Bis[2-(D-galactopyranos-6-yloxy)ethyl]-amino}azobenzene. Various other Ascomycota fungi show a similar potential to decolourise Glycoazodyes, but to a lesser extent. Detoxification has been measured, using the Daphnia magna acute toxicity test, showing a 92% dye detoxification after 6 days. This detoxification method produces low concentrations of nitrobenzene, aniline, and nitrosobenzene. | 0 | Theoretical and Fundamental Chemistry |
Some examples of stannide Zintl ions are listed below. Some of them contain 2-centre 2-electron bonds (2c-2e), others are "electron deficient" and bonding sometimes can be described using polyhedral skeletal electron pair theory (Wades rules) where the number of valence electrons contributed by each tin atom is considered to be 2 (the s electrons do not contribute). There are some examples of silicide and plumbide ions with similar structures, for example tetrahedral , the chain anion (Si), and .
*Sn found for example in MgSn.
*, tetrahedral with 2c-2e bonds e.g. in CsSn.
*, tetrahedral closo-cluster with 10 electrons (2n + 2).
*(Sn) zig-zag chain polymeric anion with 2c-2e bonds found for example in BaSn.
* closo-cluster, 12 electrons (2n + 2), (i.e. trigonal bipyramidal) in (2,2,2-crypt-Na)Sn.
* polymeric two-dimensional anion in NaSn.
* nido-cluster 22 electrons (2n + 4), capped square antiprismatic with as per polyhedral skeletal electron pair theory, in the intermetallic KSn, and a distorted ion in the salt NaSn·7 en.
* a paramagnetic, 21 electrons, closo- cluster anion (D symmetry), 1 more electron than the 20 (2n + 2) predicted by polyhedral skeletal electron pair theory.
* polymeric two-dimensional anion in NaSn | 0 | Theoretical and Fundamental Chemistry |
Many of the other quantities of information theory can be interpreted as applications of relative entropy to specific cases. | 0 | Theoretical and Fundamental Chemistry |
Viscosity is usually described as the property of a fluid which determines the rate at which local momentum differences are equilibrated. Rotational viscosity is a property of a fluid which determines the rate at which local angular momentum differences are equilibrated. In the classical case, by the equipartition theorem, at equilibrium, if particle collisions can transfer angular momentum as well as linear momentum, then these degrees of freedom will have the same average energy. If there is a lack of equilibrium between these degrees of freedom, then the rate of equilibration will be determined by the rotational viscosity coefficient.
Rotational viscosity has traditionally been thought to require rotational degrees of freedom for the fluid particles, such as in liquid crystals. In these fluids, the rotational degrees of freedom allow angular momentum to become a dynamical quantity that can be locally relaxed, leading to rotational viscosity. However, recent theoretical work has predicted that rotational viscosity ought to also be present in viscous electron fluids (see Gurzhi effect) in anisotropic metals. In these cases, the ionic lattice explicitly breaks rotational symmetry and applies torques to the electron fluid, implying non-conservation of angular momentum and hence rotational viscosity. | 1 | Applied and Interdisciplinary Chemistry |
Molecular machines are molecules or molecular assemblies that can perform functions such as linear or rotational movement, switching, and entrapment. These devices exist at the boundary between supramolecular chemistry and nanotechnology, and prototypes have been demonstrated using supramolecular concepts. Jean-Pierre Sauvage, Sir J. Fraser Stoddart and Bernard L. Feringa shared the 2016 Nobel Prize in Chemistry for the design and synthesis of molecular machines. | 0 | Theoretical and Fundamental Chemistry |
The reactions are due to collisions of reactant species. The frequency with which the molecules or ions collide depends upon their concentrations. The more crowded the molecules are, the more likely they are to collide and react with one another. Thus, an increase in the concentrations of the reactants will usually result in the corresponding increase in the reaction rate, while a decrease in the concentrations will usually have a reverse effect. For example, combustion will occur more rapidly in pure oxygen than in air (21% oxygen).
The rate equation shows the detailed dependence of the reaction rate on the concentrations of reactants and other species present. The mathematical forms depend on the reaction mechanism. The actual rate equation for a given reaction is determined experimentally and provides information about the reaction mechanism. The mathematical expression of the rate equation is often given by
Here is the reaction rate constant, is the molar concentration of reactant i and is the partial order of reaction for this reactant. The partial order for a reactant can only be determined experimentally and is often not indicated by its stoichiometric coefficient. | 0 | Theoretical and Fundamental Chemistry |
Stuntman and comedian Steve-O has publicly spoken of his involvement as a test subject in an early ractopamine study whose aim was to determine the stress limits of ractopamine saturation in humans. Glover says "Based on how dangerous the study was, the more money you get." | 0 | Theoretical and Fundamental Chemistry |
A simple qualitative method to determine the presence of phosphate ions in a sample is as follows. A small amount of the sample is acidified with concentrated nitric acid, to which a little ammonium molybdate is added. The presence of phosphate ions is indicated by the formation of a bright yellow precipitate layer of ammonium phosphomolybdate. The appearance of the precipitate can be facilitated by gentle heating. This test is also used to detect arsenic, a yellow precipitate being formed. | 0 | Theoretical and Fundamental Chemistry |
Sulfide stress cracking (SSC) is a form of hydrogen embrittlement which is a cathodic cracking mechanism. It should not be confused with the term stress corrosion cracking which is an anodic cracking mechanism. Susceptible alloys, especially steels, react with hydrogen sulfide (), forming metal sulfides (MeS) and atomic hydrogen (H) as corrosion byproducts. Atomic hydrogen either combines to form H at the metal surface or diffuses into the metal matrix. Since sulfur is a hydrogen recombination poison, the amount of atomic hydrogen which recombines to form H on the surface is greatly reduced, thereby increasing the amount of diffusion of atomic hydrogen into the metal matrix. This aspect is what makes wet HS environments so severe.
Since SSC is a form of hydrogen embrittlement, it is most susceptibile to cracking at or slightly below ambient temperature.
Sulfide stress cracking has special importance in the gas and oil industry, as the materials being processed there (natural gas and crude oil) often contain considerable amounts of hydrogen sulfide. Equipment that comes in contact with HS environments can be rated for sour service with adherence to NACE MR0175/ISO 15156 for oil and gas production environments or NACE MR0103/ISO17945 for oil and gas refining environments.
"High Temperature Hydrogen Attack" (HTHA) does not rely on atomic hydrogen. At high temperature and high hydrogen partial pressure, hydrogen can diffuse into carbon steel alloys. In susceptible alloys, hydrogen combines with carbon within the alloy and forms methane. The methane molecules create a pressure buildup in the metal lattice voids, which leads to embrittlement and even cracking of the metal. | 1 | Applied and Interdisciplinary Chemistry |
The Kelvin probe force microscope or Kelvin force microscope (KFM) is based on an AFM set-up and the determination of the work function is based on the measurement of the electrostatic forces between the small AFM tip and the sample. The conducting tip and the sample are characterized by (in general) different work functions, which represent the difference between the Fermi level and the vacuum level for each material. If both elements were brought in contact, a net electric current would flow between them until the Fermi levels were aligned. The difference between the work functions is called the contact potential difference and is denoted generally with V. An electrostatic force exists between tip and sample, because of the electric field between them. For the measurement a voltage is applied between tip and sample, consisting of a DC-bias V and an AC-voltage V sin(ωt) of frequency ω.
Tuning the AC-frequency to the resonant frequency of the AFM cantilever results in an improved sensitivity. The electrostatic force in a capacitor may be found by differentiating the energy function with respect to the separation of the elements and can be written as
where C is the capacitance, z is the separation, and V is the voltage, each between tip and surface. Substituting the previous formula for voltage (V) shows that the electrostatic force can be split up into three contributions, as the total electrostatic force F acting on the tip then has spectral components at the frequencies ω and 2ω.
The DC component, F, contributes to the topographical signal, the term F at the characteristic frequency ω is used to measure the contact potential and the contribution F can be used for capacitance microscopy. | 0 | Theoretical and Fundamental Chemistry |
As discussed in the operation section, the resolution bandwidth filter or RBW filter is the bandpass filter in the IF path. It's the bandwidth of the RF chain before the detector (power measurement device). It determines the RF noise floor and how close two signals can be and still be resolved by the analyzer into two separate peaks. Adjusting the bandwidth of this filter allows for the discrimination of signals with closely spaced frequency components, while also changing the measured noise floor. Decreasing the bandwidth of an RBW filter decreases the measured noise floor and vice versa. This is due to higher RBW filters passing more frequency components through to the envelope detector than lower bandwidth RBW filters, therefore a higher RBW causes a higher measured noise floor. | 0 | Theoretical and Fundamental Chemistry |
* A model for testing performance was determined that, when combined with the vortex lattice (VLM) or boundary element method (BEM), RANS was found useful for modelling the flow of water between two contrary rotation propellers, where VLM or BEM are applied to the propellers and RANS is used for the dynamically fluxing inter-propeller state.
* The RANS equations have been widely utilized as a model for determining flow characteristics and assessing wind comfort in urban environments. This computational approach can be executed through direct calculations involving the solution of the RANS equations, or through an indirect method involving the training of machine learning algorithms using the RANS equations as a basis. The direct approach is more accurate than the indirect approach but it requires expertise in numerical methods and computational fluid dynamics (CFD), as well as substantial computational resources to handle the complexity of the equations. | 1 | Applied and Interdisciplinary Chemistry |
In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro ("in glass"). The process involves monitoring and stimulating a womans ovulatory process, removing an ovum or ova (egg or eggs) from their ovaries and letting a mans sperm fertilise them in a culture medium in a laboratory. After the fertilised egg (zygote) undergoes embryo culture for 2–6 days, it is transferred by catheter into the uterus, with the intention of establishing a successful pregnancy.
IVF is a type of assisted reproductive technology used for infertility treatment, gestational surrogacy, and, in combination with pre-implantation genetic testing, avoiding transmission of genetic conditions. A fertilised egg from a donor may implant into a surrogate's uterus, and the resulting child is genetically unrelated to the surrogate. Some countries have banned or otherwise regulate the availability of IVF treatment, giving rise to fertility tourism. Restrictions on the availability of IVF include costs and age, in order for a person to carry a healthy pregnancy to term. Children born through IVF are colloquially called test tube babies.
In July 1978, Louise Brown was the first child successfully born after her mother received IVF treatment. Brown was born as a result of natural-cycle IVF, where no stimulation was made. The procedure took place at Dr Kershaws Cottage Hospital (now Dr Kershaws Hospice) in Royton, Oldham, England. Robert Edwards was awarded the Nobel Prize in Physiology or Medicine in 2010. The physiologist co-developed the treatment together with Patrick Steptoe and embryologist Jean Purdy but the latter two were not eligible for consideration as they had died and the Nobel Prize is not awarded posthumously.
Assisted by egg donation and IVF, there are many women who may be past their reproductive years, have infertile partners, have idiopathic female-fertility issues, or have reached menopause, that can still become pregnant. After the IVF treatment, some couples get pregnant without any fertility treatments. In 2023, it was estimated that twelve million children had been born worldwide using IVF and other assisted reproduction techniques. A 2019 study that explores 10 adjuncts with IVF (screening hysteroscopy, DHEA, testosterone, GH, aspirin, heparin, antioxidants, seminal plasma and PRP) suggests that until more evidence is done to show that these adjuncts are safe and effective, they should be avoided. | 1 | Applied and Interdisciplinary Chemistry |
Phanes are abstractions of highly complex organic molecules introduced for simplification of the naming of these highly complex molecules.
Systematic nomenclature of organic chemistry consists of building a name for the structure of an organic compound by a collection of names of its composite parts but describing also its relative positions within the structure. Naming information is summarised by IUPAC:
Whilst the cyclophane name describes only a limited number of sub-structures of benzene rings interconnected by individual atoms or chains, phane is a class name which includes others, hence heterocyclic rings as well. Therefore, the various cyclophanes are perfectly good for the general class of phanes as well keeping in mind that the cyclic structures in phanes could have much greater diversity. | 0 | Theoretical and Fundamental Chemistry |
William Martin and Michael Russell suggest that the first cellular life forms may have evolved inside alkaline hydrothermal vents at seafloor spreading zones in the deep sea. These structures consist of microscale caverns that are coated by thin membraneous metal sulfide walls. Therefore, these structures would resolve several critical points germane to Wächtershäuser's suggestions at once:
# the micro-caverns provide a means of concentrating newly synthesised molecules, thereby increasing the chance of forming oligomers;
# the steep temperature gradients inside the hydrothermal vent allow for establishing "optimum zones" of partial reactions in different regions of the vent (e.g. monomer synthesis in the hotter, oligomerisation in the cooler parts);
# the flow of hydrothermal water through the structure provides a constant source of building blocks and energy (chemical disequilibrium between hydrothermal hydrogen and marine carbon dioxide);
# the model allows for a succession of different steps of cellular evolution (prebiotic chemistry, monomer and oligomer synthesis, peptide and protein synthesis, RNA world, ribonucleoprotein assembly and DNA world) in a single structure, facilitating exchange between all developmental stages;
# synthesis of lipids as a means of "closing" the cells against the environment is not necessary, until basically all cellular functions are developed.
This model locates the "last universal common ancestor" (LUCA) within the inorganically formed physical confines of an alkaline hydrothermal vent, rather than assuming the existence of a free-living form of LUCA. The last evolutionary step en route to bona fide free-living cells would be the synthesis of a lipid membrane that finally allows the organisms to leave the microcavern system of the vent. This postulated late acquisition of the biosynthesis of lipids as directed by genetically encoded peptides is consistent with the presence of completely different types of membrane lipids in archaea and bacteria (plus eukaryotes). The kind of vent at the foreground of their suggestion is chemically more similar to the warm (ca. 100 °C) off ridge vents such as Lost City than to the more familiar black smoker type vents (ca. 350 °C).
In an abiotic world, a thermocline of temperatures and a chemocline in concentration is associated with the pre-biotic synthesis of organic molecules, hotter in proximity to the chemically rich vent, cooler but also less chemically rich at greater distances. The migration of synthesized compounds from areas of high concentration to areas of low concentration gives a directionality that provides both source and sink in a self-organizing fashion, enabling a proto-metabolic process by which acetic acid production and its eventual oxidization can be spatially organized.
In this way many of the individual reactions that are today found in central metabolism could initially have occurred independent of any developing cell membrane. Each vent microcompartment is functionally equivalent to a single cell. Chemical communities having greater structural integrity and resilience to wildly fluctuating conditions are then selected for; their success would lead to local zones of depletion for important precursor chemicals. Progressive incorporation of these precursor components within a cell membrane would gradually increase metabolic complexity within the cell membrane, whilst leading to greater environmental simplicity in the external environment. In principle, this could lead to the development of complex catalytic sets capable of self-maintenance.
Russell adds a significant factor to these ideas, by pointing out that semi-permeable mackinawite (an iron sulfide mineral) and silicate membranes could naturally develop under these conditions and electrochemically link reactions separated in space, if not in time. | 1 | Applied and Interdisciplinary Chemistry |
* Cyanofullerenes are a class of modified fullerenes in which cyano- groups are attached to a fullerene skeleton. These have the formula , where n takes the values 1 to 9. | 0 | Theoretical and Fundamental Chemistry |
The enantiomers of axially chiral compounds are usually given the stereochemical labels (R) and (S), sometimes abbreviated (R) and (S). The designations are based on the same Cahn–Ingold–Prelog priority rules used for tetrahedral stereocenters. The chiral axis is viewed end-on and the two "near" and two "far" substituents on the axial unit are ranked, but with the additional rule that the two near substituents have higher priority than the far ones. | 0 | Theoretical and Fundamental Chemistry |
Widely known methods of structural investigation, such as mass-spectrometry and X-ray analysis are only limitedly applicable to carbohydrates. Such structural studies, such as sequence determination or identification of new monosaccharides, benefit the most from the NMR spectroscopy.
Absolute configuration and polymerization degree are not always determinable using NMR only, so the process of structural elucidation may require additional methods. Although monomeric composition can be solved by NMR, chromatographic and mass-spectroscopic methods provide this information sometimes easier. The other structural features listed above can be determined solely by the NMR spectroscopic methods.
The limitation of the NMR structural studies of carbohydrates is that structure elucidation can hardly be automatized and require a human expert to derive a structure from NMR spectra. | 0 | Theoretical and Fundamental Chemistry |
* Important publications in biochemistry (chemistry)
* List of biochemistry topics
* List of biochemists
* List of biomolecules | 1 | Applied and Interdisciplinary Chemistry |
Pipe installation is often more expensive than the material and a variety of specialized tools, techniques, and parts have been developed to assist this. Pipe is usually delivered to a customer or jobsite as either "sticks" or lengths of pipe (typically , called single random length) or they are prefabricated with elbows, tees and valves into a prefabricated pipe spool [A pipe spool is a piece of pre-assembled pipe and fittings, usually prepared in a shop so that installation on the construction site can be more efficient.]. Typically, pipe smaller than are not pre-fabricated. The pipe spools are usually tagged with a bar code and the ends are capped (plastic) for protection. The pipe and pipe spools are delivered to a warehouse on a large commercial/industrial job and they may be held indoors or in a gridded laydown yard. The pipe or pipe spool is retrieved, staged, rigged, and then lifted into place. On large process jobs the lift is made using cranes and hoist and other material lifts. They are typically temporarily supported in the steel structure using beam clamps, straps, and small hoists until the pipe supports are attached or otherwise secured.
An example of a tool used for installation for a small plumbing pipe (threaded ends) is the pipe wrench. Small pipe is typically not heavy and can be lifted into place by the installation craft laborer. However, during a plant outage or shutdown, the small (small bore) pipe may also be pre-fabricated to expedite installation during the outage. After the pipe is installed it will be tested for leaks. Before testing it may need to be cleaned by blowing air or steam or flushing with a liquid. | 1 | Applied and Interdisciplinary Chemistry |
Highly-fermentable fiber residues, such as those from resistant starch, oat bran, pectin, and guar are transformed by colonic bacteria into short-chain fatty acids (SCFA) including butyrate, producing more SCFA than less fermentable fibers such as celluloses. One study found that resistant starch consistently produces more butyrate than other types of dietary fiber. The production of SCFA from fibers in ruminant animals such as cattle is responsible for the butyrate content of milk and butter.
Fructans are another source of prebiotic soluble dietary fibers which can be digested to produce butyrate. They are often found in the soluble fibers of foods which are high in sulfur, such as the allium and cruciferous vegetables. Sources of fructans include wheat (although some wheat strains such as spelt contain lower amounts), rye, barley, onion, garlic, Jerusalem and globe artichoke, asparagus, beetroot, chicory, dandelion leaves, leek, radicchio, the white part of spring onion, broccoli, brussels sprouts, cabbage, fennel, and prebiotics, such as fructooligosaccharides (FOS), oligofructose, and inulin. | 1 | Applied and Interdisciplinary Chemistry |
Activity coefficients for binary mixtures are often reported at the infinite dilution of each component. Because activity coefficient models simplify at infinite dilution, such empirical values can be used to estimate interaction energies. Examples are given for water: | 0 | Theoretical and Fundamental Chemistry |
One goal of alchemy, the transmutation of base substances into gold, is now known to be impossible by means of traditional chemistry, but possible by other physical means. Although not financially worthwhile, gold was synthesized in particle accelerators as early as 1941. | 1 | Applied and Interdisciplinary Chemistry |
The I isotope is also used as a radioactive label for certain radiopharmaceuticals that can be used for therapy, e.g. I-metaiodobenzylguanidine (I-MIBG) for imaging and treating pheochromocytoma and neuroblastoma. In all of these therapeutic uses, I destroys tissue by short-range beta radiation. About 90% of its radiation damage to tissue is via beta radiation, and the rest occurs via its gamma radiation (at a longer distance from the radioisotope). It can be seen in diagnostic scans after its use as therapy, because I is also a gamma-emitter. | 0 | Theoretical and Fundamental Chemistry |
In his exposition of his scheme of closed system equilibrium thermodynamics, C. Carathéodory initially postulates that experiment reveals that a definite number of real variables define the states that are the points of the manifold of equilibria. In the words of Prigogine and Defay (1945): "It is a matter of experience that when we have specified a certain number of macroscopic properties of a system, then all the other properties are fixed." As noted above, according to A. Münster, the number of variables needed to define a thermodynamic equilibrium is the least for any state of a given isolated system. As noted above, J.G. Kirkwood and I. Oppenheim point out that a state of thermodynamic equilibrium may be defined by a special subclass of intensive variables, with a definite number of members in that subclass.
If the thermodynamic equilibrium lies in an external force field, it is only the temperature that can in general be expected to be spatially uniform. Intensive variables other than temperature will in general be non-uniform if the external force field is non-zero. In such a case, in general, additional variables are needed to describe the spatial non-uniformity. | 0 | Theoretical and Fundamental Chemistry |
Imipenem acts as an antimicrobial through inhibiting cell wall synthesis of various Gram-positive and Gram-negative bacteria. It remains very stable in the presence of β-lactamase (both penicillinase and cephalosporinase) produced by some bacteria, and is a strong inhibitor of β-lactamases from some Gram-negative bacteria that are resistant to most β-lactam antibiotics. | 0 | Theoretical and Fundamental Chemistry |
The last abundant subset of thymic DCs is represented by B220 plasmacytoid DCs (pDCs) which also rise extrathymically and transfer peripheral antigens from the periphery to the thymus to mediate selection processes.
All these thymic DC subsets were shown to participate in antigen transfer. Nevertheless, only tDCs and mDCs were observed to utilize transferred TRAs for indirect presentation which led to the processes of central tolerance. | 1 | Applied and Interdisciplinary Chemistry |
Scientists Miriam Paredes and Maria Quiles led an investigation on the plant species Rosa Meillandina, and its metabolic response to water deficit. They noted how limited water irrigation can cause a reduction in PS II levels, which then results in the inhibition of photosynthesis. Paredes and Quiles also noticed the increase in chlororespiration activity as a protective mechanism for the lack of photosynthesis.
In the experiment, the plants in water deficit were analysed with fluorescence imaging technique. This form of analysis detected increased levels of PTOX, and NAD(P)H activity within the plant. An increase in these two molecules led to the initiation of chlororespiration.
N-propyl gallate was also added to these water deficit plants. The effect resulted in increased chlorophyll fluorescence levels. Quiles recorded a similar outcome in the same species of plants that went under intense light. This increase in chlorophyll fluorescence is attributed to the influx of NAD(P)H in the thylakoid membrane. Which then led to an increase in the by-product, hydrogen peroxide, inside the thylakoid membrane. | 1 | Applied and Interdisciplinary Chemistry |
Volatiles are present in nearly all magma in different concentrations. Examples of volatiles within magma include water, carbon dioxide, and halogen gases. High pressures allow these volatiles to stay relatively stable within solution. However, over time, as the magmatic pressure decreases, volatiles will rise out of solution in the gaseous phase, further decreasing the magmatic pressure. These pressure differences cause drastic differences in the volume of a magma. Pressure difference causes some forms of volcanoes to be highly explosive and others to be effusive. | 0 | Theoretical and Fundamental Chemistry |
In 1898, the physiologist Robert Tigerstedt and his student, Per Bergman, experimented with rabbits by injecting them with kidney extracts. Their results suggested the kidneys produced a protein, which they named renin, that caused a rise in blood pressure. In the 1930s, Goldblatt conducted experiments where he constricted the renal blood flow in dogs; he found the ischaemic kidneys did in fact secrete a chemical that caused vasoconstriction. In 1939, renin was found not to cause the rise in blood pressure, but was an enzyme which catalyzed the formation of the substances that were responsible, namely, angiotensin I (Ang I) and Ang II.
In the 1970s, scientists first observed Ang II to harm the heart and kidneys, and individuals with high levels of renin activity in plasma were at increased risk of myocardial infarction and stroke.
With the introduction of angiotensin converting enzyme (ACE) inhibitors in the late 1970s it was confirmed that Ang II plays an important role in regulating blood pressure and electrolyte and fluid balance.
Before that attempts had been made to develop useful Ang II receptor antagonists and initially, the main focus was on angiotensin peptide analogues. Saralasin and other Ang II analogues were potent Ang II receptor blockers but the main problem was a lack of oral bioavailability.
In the early 1980s it was noted that a series of imidazole-5-acetic acid derivatives diminished blood pressure responses to Ang II in rats. Two compounds, S-8307 and S-8308, were later found to be highly specific and promising non-peptide Ang II receptor antagonists but using molecular modeling it was seen that their structures would have to mimic more closely the pharmacophore of Ang II. Structural modifications were made and the orally active, potent and selective nonpeptide AT receptor blocker losartan was developed. In 1995 losartan was approved for clinical use in the United States and since then six additional ARBs have been approved. These drugs are known for their excellent side-effects profiles, which clinical trials have shown to be similar to those of placebos. | 1 | Applied and Interdisciplinary Chemistry |
When the force is associated with a potential energy (see conservative force), a steady-state solution to the above equation (i.e. ) is:
(assuming and are constant). In other words, there are more particles where the energy is lower. This concentration profile is expected to agree with the Boltzmann distribution (more precisely, the Gibbs measure). From this assumption, the Einstein relation can be proven: | 1 | Applied and Interdisciplinary Chemistry |
The fluid flows in microfluidic and nanofluidic devices are often stable and strongly damped by viscous forces (with Reynolds numbers of order unity or smaller). However, heterogeneous ionic conductivity fields in the presence of applied electric fields can, under certain conditions, generate an unstable flow field owing to electrokinetic instabilities (EKI). Conductivity gradients are prevalent in on-chip electrokinetic processes such as preconcentration methods (e.g. field amplified sample stacking and isoelectric focusing), multidimensional assays, and systems with poorly specified sample chemistry. The dynamics and periodic morphology of electrokinetic instabilities are similar to other systems with Rayleigh–Taylor instabilities. The particular case of a flat plane geometry with homogeneous ions injection in the bottom side leads to a mathematical frame identical to the Rayleigh–Bénard convection.
EKI's can be leveraged for rapid mixing or can cause undesirable dispersion in sample injection, separation and stacking. These instabilities are caused by a coupling of electric fields and ionic conductivity gradients that results in an electric body force. This coupling results in an electric body force in the bulk liquid, outside the electric double layer, that can generate temporal, convective, and absolute flow instabilities. Electrokinetic flows with conductivity gradients become unstable when the electroviscous stretching and folding of conductivity interfaces grows faster than the dissipative effect of molecular diffusion.
Since these flows are characterized by low velocities and small length scales, the Reynolds number is below 0.01 and the flow is laminar. The onset of instability in these flows is best described as an electric "Rayleigh number". | 1 | Applied and Interdisciplinary Chemistry |
Ion separation is another application of magnetic separation. The separation is driven by the magnetic field that induces a separating force. The force differentiate then between heavy and lighter ions causing the separation. This phenomenon has been demonstrated on test bench and pilot scale. | 0 | Theoretical and Fundamental Chemistry |
In some cases, chemical trap is used to detect or infer a compound when present at concentrations below its detection limit or is present in a mixture, where other components interfere with its detection. The trapping agent, for example a dye, reacts with the chemical to be detected, giving a product that is more easily detected. | 0 | Theoretical and Fundamental Chemistry |
Organ printing for medical applications is still in the developmental stages. Thus, the long term impacts of organ printing have yet to be determined. Researchers hope that organ printing could decrease the organ transplant shortage. There is currently a shortage of available organs, including liver, kidneys, and lungs. The lengthy wait time to receive life saving organs is one of the leading causes of death in the United States, with nearly one third of deaths each year in the United States that could be delayed or prevented with organ transplants. Currently the only organ that has been 3D bioprinted and successfully transplanted into a human is a bladder. The bladder was formed from the host's bladder tissue. Researchers have proposed that a potential positive impact of 3D printed organs is the ability to customize organs for the recipient. Developments enabling an organ recipient’s host cells to be used to synthesize organs decreases the risk of organ rejection.
The ability to print organs has decreased the demand for animal testing. Animal testing is used to determine the safety of products ranging from makeup to medical devices. Cosmetic companies are already using smaller tissue models to test new products on skin. The ability to 3D print skin reduces the need for animal trials for makeup testing. In addition, the ability to print models of human organs to test the safety and efficacy of new drugs further reduces the necessity for animal trials. Researchers at Harvard University determined that drug safety can be accurately tested on smaller tissue models of lungs. The company Organovo, which designed one of the initial commercial bioprinters in 2009, has displayed that biodegradable 3D tissue models can be used to research and develop new drugs, including those to treat cancer. An additional impact of organ printing includes the ability to rapidly create tissue models, therefore increasing productivity. | 1 | Applied and Interdisciplinary Chemistry |
Renewable energy company Bord na Móna began peat moss trials in 2012 to restore Sphagnum in raised bogs for potential horticulture. | 1 | Applied and Interdisciplinary Chemistry |
Diradicals are molecules containing two radical centers. Dioxygen (O) is an important example of a stable diradical. Singlet oxygen, the lowest-energy non-radical state of dioxygen, is less stable than the diradical due to Hund's rule of maximum multiplicity. The relative stability of the oxygen diradical is primarily due to the spin-forbidden nature of the triplet-singlet transition required for it to grab electrons, i.e., "oxidize". The diradical state of oxygen also results in its paramagnetic character, which is demonstrated by its attraction to an external magnet. Diradicals can also occur in metal-oxo complexes, lending themselves for studies of spin forbidden reactions in transition metal chemistry. Carbenes in their triplet state can be viewed as diradicals centred on the same atom, while these are usually highly reactive persistent carbenes are known, with N-heterocyclic carbenes being the most common example.
Triplet carbenes and nitrenes are diradicals. Their chemical properties are distinct from the properties of their singlet analogues. | 1 | Applied and Interdisciplinary Chemistry |
Lipase inhibitors belong to a drug class that is used as an antiobesity agent. Their mode of action is to inhibit gastric and pancreatic lipases, enzymes that play an important role in the digestion of dietary fat. Lipase inhibitors are classified in the ATC-classification system as A08AB (peripherally acting antiobesity products).
Numerous compounds have been either isolated from nature, semi-synthesized, or fully synthesized and then screened for their lipase inhibitory activity but the only lipase inhibitor on the market (October 2016) is orlistat (Xenical, Alli).
Lipase inhibitors have also shown anticancer activity, by inhibiting fatty acid synthase. | 1 | Applied and Interdisciplinary Chemistry |
There may be equilibrium fractionation between coexisting minerals. This would be particularly relevant when considering the formation of planetary bodies early in the solar system. Experiments have aimed to simulate the formation of the Earth at high temperatures using a platinum-iron alloy and an analog for the silicate earth at 1,500 °C. However, the observed fractionation was very small, less than 0.2‰ per atomic mass unit. More experimental work is needed to fully understand this effect. | 0 | Theoretical and Fundamental Chemistry |
The presence of nearby particles will affect the radiation emitted by an individual particle. There are two limiting cases by which this occurs:
* Impact pressure broadening or collisional broadening: The collision of other particles with the light emitting particle interrupts the emission process, and by shortening the characteristic time for the process, increases the uncertainty in the energy emitted (as occurs in natural broadening). The duration of the collision is much shorter than the lifetime of the emission process. This effect depends on both the density and the temperature of the gas. The broadening effect is described by a Lorentzian profile and there may be an associated shift.
* Quasistatic pressure broadening: The presence of other particles shifts the energy levels in the emitting particle (see spectral band), thereby altering the frequency of the emitted radiation. The duration of the influence is much longer than the lifetime of the emission process. This effect depends on the density of the gas, but is rather insensitive to temperature. The form of the line profile is determined by the functional form of the perturbing force with respect to distance from the perturbing particle. There may also be a shift in the line center. The general expression for the lineshape resulting from quasistatic pressure broadening is a 4-parameter generalization of the Gaussian distribution known as a stable distribution.
Pressure broadening may also be classified by the nature of the perturbing force as follows:
* Linear Stark broadening occurs via the linear Stark effect, which results from the interaction of an emitter with an electric field of a charged particle at a distance , causing a shift in energy that is linear in the field strength.
* Resonance broadening occurs when the perturbing particle is of the same type as the emitting particle, which introduces the possibility of an energy exchange process.
* Quadratic Stark broadening occurs via the quadratic Stark effect, which results from the interaction of an emitter with an electric field, causing a shift in energy that is quadratic in the field strength.
* Van der Waals broadening occurs when the emitting particle is being perturbed by Van der Waals forces. For the quasistatic case, a Van der Waals profile is often useful in describing the profile. The energy shift as a function of distance between the interacting particles is given in the wings by e.g. the Lennard-Jones potential. | 0 | Theoretical and Fundamental Chemistry |
Anthocyanins are thought to be subject to physiochemical degradation in vivo and in vitro. Structure, pH, temperature, light, oxygen, metal ions, intramolecular association, and intermolecular association with other compounds (copigments, sugars, proteins, degradation products, etc.) generally are known to affect the color and stability of anthocyanins. B-ring hydroxylation status and pH have been shown to mediate the degradation of anthocyanins to their phenolic acid and aldehyde constituents. Indeed, significant portions of ingested anthocyanins are likely to degrade to phenolic acids and aldehyde in vivo, following consumption. This characteristic confounds scientific isolation of specific anthocyanin mechanisms in vivo. | 0 | Theoretical and Fundamental Chemistry |
During the 1950s, Bernard Katz and Paul Fatt observed spontaneous miniature synaptic currents at the frog neuromuscular junction. Based on these observations, they developed the quantal hypothesis that is the basis for our current understanding of neurotransmitter release as exocytosis and for which Katz received the Nobel Prize in Physiology or Medicine in 1970. In the late 1960s, Ricardo Miledi and Katz advanced the hypothesis that depolarization-induced influx of calcium ions triggers exocytosis.
Sir Charles Scott Sherringtonin coined the word synapse and the history of the word was given by Sherrington in a letter he wrote to John Fulton: | 1 | Applied and Interdisciplinary Chemistry |
In a Latimer diagram, the most highly oxidized form of the element is on the left side, with successively lower oxidation states to the right side. The species are connected by arrows, and the numerical value of the standard potential (in volts) for the reduction is written at each arrow. For example, for oxygen, the species would be in the order O (0), HO (–1), HO (-2):
The arrow between O and HO has a value +0.68 V over it, it indicates that the standard electrode potential for the reaction:
:O(g) + 2H + 2e ⇄ HO(aq)
is 0.68 volts. | 0 | Theoretical and Fundamental Chemistry |
N-Chlorosuccinimide ("NCS")is the organic compound with the formula CH(CO)NCl. A white solid, it is used for chlorinations. It is also used as a mild oxidant. NCS is related to succinimide, but with N-Cl in place of N-H. The N–Cl bond is highly reactive, and NCS functions as a source of "Cl". | 0 | Theoretical and Fundamental Chemistry |
For any point in a unit cell, given by fractional coordinates, one can apply a symmetry operation to the point. In some cases it will move to new coordinates, while in other cases the point will remain unaffected. For example, reflecting across a mirror plane will switch all the points left and right of the mirror plane, but points exactly on the mirror plane itself will not move. We can test every symmetry operation in the crystals point group and keep track of whether the specified point is invariant under the operation or not. The (finite) list of all symmetry operations which leave the given point invariant taken together make up another group, which is known as the site symmetry group' of that point. By definition, all points with the same site symmetry group, or a conjugate site symmetry group, are assigned the same Wyckoff position.
The Wyckoff positions are designated by a letter, often preceded by the number of positions that are equivalent to a given position with that letter, in other words the number of positions in the unit cell to which the given position is moved by applying all the elements of the space group. For instance, 2a designates the positions left where they are by a certain subgroup, and indicates that other symmetry elements move the point to a second position in the unit cell. The letters are assigned in alphabetical order with earlier letters indicating positions with fewer equivalent positions, or in other words with larger site symmetry groups. Some designations may apply to a finite number of points per unit cell (such as inversion points, improper rotation points, and intersections of rotation axes with mirror planes or other rotation axes), but other designations apply to infinite sets of points (such as generic points on rotation axes, screw axes, mirror planes, and glide planes, as well as general points not lying on any symmetry axis or plane).
Wyckoff positions are used in calculations of crystal properties. There are two types of positions: general and special.
*General positions are left invariant only for the identity operation (E). Each space group has only one general position.
*Special positions are left invariant by the identity operation and at least one other operation of the space group.
General positions have a site symmetry of the trivial group and all correspond to the same Wyckoff position. Special positions have a non-trivial site symmetry group.
For a particular space group, one can check the Wyckoff positions using International Tables of Crystallography. The table presents the multiplicity, Wyckoff letter and site symmetry for Wyckoff positions. | 0 | Theoretical and Fundamental Chemistry |
*Herta Leng Memorial Lecture Series, Rensselaer Polytechnic Institute
Every year, RPI honors Leng with the Herta Leng Memorial Lecture Series. | 0 | Theoretical and Fundamental Chemistry |
The robustness of focal molography against environmental noise gives the method a platform character that enables many possible applications. They range from the investigation of a specific biomolecular interaction in basic biological research to the diagnosis of a critical health condition in an emergency.
The biological applications of molography categorize into five basic classes:
# Classical biomolecular interaction analysis (BIA), i.e. the measurement of on-rates, off-rates and binding constants as demonstrated in,
# Quantification of biomarkers in biological samples,
# Profiling of low-affinity binders on mologram arrays,
# Quantification of molecular interactions in living cells in real time, and
# Discovery of unknown biomolecular interactions by means of binding assays. | 1 | Applied and Interdisciplinary Chemistry |
The ashes of glasswort plants, and also of their Mediterranean counterpart saltwort plants, yield soda ash, which is an important ingredient for glassmaking and soapmaking. Soda ash is an alkali whose active ingredient is now known to be sodium carbonate.
Glasswort and saltwort plants sequester the sodium they absorb from salt water into their tissues (see Salsola soda). Ashing of the plants converts some of this sodium into sodium carbonate (or "soda", in one of the old uses of the term).
In the medieval and early post-medieval centuries, various glasswort plants were collected at tidal marshes and other saline places in the Mediterranean region. The collected plants were burned. The resulting ashes were mixed with water. Sodium carbonate is soluble in water. Non-soluble components of the ashes sank to the bottom of the water container. The water with the sodium carbonate dissolved in it was then transferred to another container, and then the water was evaporated off, leaving behind the sodium carbonate. Another major component of the ashes that is soluble in water is potassium carbonate, a.k.a. potash. The resulting product consisted mainly of a mixture of sodium carbonate and potassium carbonate. This product was called "soda ash" (it was also called "alkali"). It contained 20% to 30% sodium carbonate. For glassmaking, it was superior to a potash product obtained by the same procedure from the ashes of non-salty plants. If plant ashes were not washed as just described, they were still usable in glassmaking but the results were not as good.
The appearance of the word glasswort in English is reasonably contemporaneous with a 16th-century resurgence in English glassmaking, which had suffered a long decline after Roman times. This resurgence was led by glassmakers who emigrated to England from Lorraine and from Venice. The Lorraine glassmakers brought with them the technology of forest glass, the greenish glass that used potash from wood ashes as a flux. The Venetian glassmakers brought with them the technology of cristallo, the immaculately clear glass that used soda ash as a flux. These glassmakers would have recognized Salicornia europaea growing in England as a source for soda ash. Prior to their arrival, it was said that the plant "hath no name in English".
By the 18th century, Spain had an enormous industry producing soda ash from saltworts; the soda ash from this source was known as barrilla. Scotland had a large 18th-century industry producing soda ash from seaweed. The source of this ash was kelp. This industry was so lucrative that it led to overpopulation in the Western Isles of Scotland, and one estimate is that 100,000 people were occupied with "kelping" during the summer months. In the same period, soda ash (la soude de Narbonne) was produced in quantity from glasswort proper around Narbonne, France. The commercialization of the Leblanc process for synthesizing sodium carbonate (from salt, limestone, and sulfuric acid) brought an end to the era of farming for soda ash in the first half of the 19th century. | 0 | Theoretical and Fundamental Chemistry |
The javelin argument, credited to Lucretius, is an ancient logical argument that the universe, or cosmological space, must be infinite. The javelin argument was used to support the Epicurean thesis about the universe. It was also constructed to counter the Aristotelian view that the universe is finite. | 1 | Applied and Interdisciplinary Chemistry |
The TRIM family is split into two groups that differ in domain structure and genomic organization:
* Group 1 members possess a variety of C-terminal domains, and are represented in both vertebrate and invertebrates
* Group 2 is absent in invertebrates, possess a C-terminal SPRY domain
Members of the family include:
* Group 1
** PHD-BROMO domain containing: TRIM24 (TIF1α), TRIM28 (TIF1β), TRIM33 (TIF1γ)– act as corepressors
** 1-10: TRIM1, TRIM2, TRIM3, TRIM8, TRIM9
** 11-20: TRIM12, TRIM13, TRIM14, TRIM16, TRIM18, TRIM19
** 21-30: TRIM23, TRIM25, TRIM29, TRIM30
** 31-40: TRIM32, TRIM36, TRIM37
** 41-50: TRIM42, TRIM44, TRIM45, TRIM46, TRIM47
** 51-60: TRIM51, TRIM53, TRIM54, TRIM55, TRIM56, TRIM57, TRIM59
** 61-70: TRIM62, TRIM63, TRIM65, TRIM66, TRIM67, TRIM69, TRIM70
** 71-75: TRIM71
* Group 2
** 1-10: TRIM4, TRIM5, TRIM6, TRIM7, TRIM10
** 11-20: TRIM11, TRIM12, TRIM15, TRIM17, TRIM20
** 21-30: TRIM21, TRIM22, TRIM26, TRIM27, TRIM30
** 31-40: TRIM31, TRIM34, TRIM35, TRIM38, TRIM39, TRIM40
** 41-50: TRIM41, TRIM43, TRIM48, TRIM49, TRIM50
** 51-60: TRIM51, TRIM52, TRIM53, TRIM57, TRIM58, TRIM60
** 61-70: TRIM61, TRIM64, TRIM68, TRIM69, TRIM70
** 71-75: TRIM72, TRIM73, TRIM74, TRIM75 | 1 | Applied and Interdisciplinary Chemistry |
A chemical structure of a molecule is a spatial arrangement of its atoms and their chemical bonds. Its determination includes a chemists specifying the molecular geometry and, when feasible and necessary, the electronic structure of the target molecule or other solid. Molecular geometry refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together and can be represented using structural formulae and by molecular models; complete electronic structure descriptions include specifying the occupation of a molecules molecular orbitals. Structure determination can be applied to a range of targets from very simple molecules (e.g., diatomic oxygen or nitrogen) to very complex ones (e.g., such as protein or DNA). | 0 | Theoretical and Fundamental Chemistry |
Some reactors are used for the neutron irradiation of samples for radioisotope production for a range of purposes. The sample can be placed in an irradiation container which is then placed in the reactor; if epithermal neutrons are required for the irradiation then cadmium can be used to filter out the thermal neutrons. | 0 | Theoretical and Fundamental Chemistry |
A diketopiperazine (DKP), also known as a dioxopiperazine or piperazinedione, is a class of organic compounds related to piperazine but containing two amide linkages. DKP's are the smallest known class of cyclic peptide. Despite their name, they are not ketones, but amides. Three regioisomers are possible, differing in the locations of the carbonyl groups.
* One isomer is an oxamide obtained from ethylenediamine.
* 2,5-Diketopiperazines are cyclodipeptides often obtainable via condensation of two α-amino acids.
* 2,6-Diketopiperazines may be viewed as cyclized imide derivatives derived from iminodiacetic acids.
Of these three isomeric diketopiperazines, the 2,5-derivatives have attracted the greatest interest. Due to their appearance in biologically active natural products, medicinal chemists have been inspired to use DKPs to circumvent the poor physical and metabolic properties of peptides in the course of drug discovery. | 0 | Theoretical and Fundamental Chemistry |
In Egypt, soil-less agriculture is used to grow plants on the roofs of buildings. No soil is placed directly on the roof itself, thus eliminating the need for an insulating layer; instead, plants are grown on wooden tables. Vegetables and fruit are the most popular candidates, providing a fresh, healthy source of food that is free from pesticides.
A more advanced method, (aquaponics), being used experimentally in Egypt, is farming fish next to plants in a closed cycle. This allows the plants to benefit from the ammonia excreted by the fish, helping the plants to grow better and at the same time eliminating the need for changing the water for the fish, because the plants help to keep it clean by absorbing the ammonia. The fish also get some nutrients from the roots of the plants. | 1 | Applied and Interdisciplinary Chemistry |
They are not necessarily mutagenic by themselves, but they produce promutagens mutagenic compounds through metabolic processes in cells.
*Polyaromatic hydrocarbons (PAHs)
*Aromatic amines
*Benzene | 0 | Theoretical and Fundamental Chemistry |
Expansibility factor, also called expansion factor, for sharp-edged orifice plates with corner, flange or D and D/2 tappings:<br />
:if (at least - standards vary)
:but for incompressible fluids, including most liquids | 1 | Applied and Interdisciplinary Chemistry |
A hidden state of matter is a state of matter which cannot be reached under ergodic conditions, and is therefore distinct from known thermodynamic phases of the material. Examples exist in condensed matter systems, and are typically reached by the non-ergodic conditions created through laser photo excitation.
Short-lived hidden states of matter have also been reported in crystals using lasers. Recently a persistent hidden state was discovered in a crystal of Tantalum(IV) sulfide (TaS), where the state is stable at low temperatures.
A hidden state of matter is not to be confused with hidden order, which exists in equilibrium, but is not immediately apparent or easily observed.
Using ultrashort laser pulses impinging on solid state matter, the system may be knocked out of equilibrium so that not only are the individual subsystems out of equilibrium with each other but also internally. Under such conditions, new states of matter may be created which are not otherwise reachable under equilibrium, ergodic system evolution.
Such states are usually unstable and decay very rapidly, typically in nanoseconds or less. The difficulty is in distinguishing a genuine hidden state from one which is simply out of thermal equilibrium.
Probably the first instance of a photoinduced state is described for the organic molecular compound TTF-CA, which turns from neutral to ionic species as a result of excitation by laser pulses. However, a similar transformation is also possible by the application of pressure, so strictly speaking the photoinduced transition is not to a hidden state under the definition given in the introductory paragraph. A few further examples are given in ref.
Photoexcitation has been shown to produce persistent states in vanadates and manganite materials,
leading to filamentary paths of a modified charge ordered phase which is sustained by a passing current. Transient superconductivity was also reported in cuprates. | 0 | Theoretical and Fundamental Chemistry |
There are two motifs to indicate a metal oxidation state based around the actual charge separation of the metal center. Oxidation states up to +3 are believed to be an accurate representation of the charge separation experienced by the metal center. For oxidation states of +4 and larger, the oxidation state becomes more of a formalism with much of the positive charge distributed between the ligands. This distinction can be expressed by using a Roman numeral for the lower oxidation states in the upper right of the metal atomic symbol and an Arabic number with a plus sign for the higher oxidation states (see the example below). This formalism is not rigorously followed and the use of Roman numerals to represent higher oxidation states is common.
:[ML] vs. [O=ML] | 0 | Theoretical and Fundamental Chemistry |
A Phred quality score is a measure of the quality of the identification of the nucleobases generated by automated DNA sequencing. It was originally developed for the computer program Phred to help in the automation of DNA sequencing in the Human Genome Project. Phred quality scores are assigned to each nucleotide base call in automated sequencer traces. The FASTQ format encodes phred scores as ASCII characters alongside the read sequences. Phred quality scores have become widely accepted to characterize the quality of DNA sequences, and can be used to compare the efficacy of different sequencing methods. Perhaps the most important use of Phred quality scores is the automatic determination of accurate, quality-based consensus sequences. | 1 | Applied and Interdisciplinary Chemistry |
In addition to receiving citations from scientific articles and theses, the Bilbao Crystallographic Server also actively publishes research reports in internationally reviewed articles, as well as hosting/participating in international workshops, summer schools and conferences. A list of these publications and events are accessible from the [http://www.cryst.ehu.es/html/doc/bcs_references.html server's web page.]. | 0 | Theoretical and Fundamental Chemistry |
It adopts "antifluorite structure," which means that the small K ions occupy the tetrahedral (F) sites in fluorite, and the larger S centers occupy the eight-coordinate sites. LiS, NaS, and RbS crystallize similarly. | 0 | Theoretical and Fundamental Chemistry |
Alkyllithium reagents form deeply colored derivatives with phenanthroline. The alkyllithium content of solutions can be determined by treatment of such reagents with small amounts of phenanthroline (ca. 1 mg) followed by titration with alcohols to a colourless endpoint. Grignard reagents may be similarly titrated. | 0 | Theoretical and Fundamental Chemistry |
The mechanism for chloroplast DNA (cpDNA) replication has not been conclusively determined, but two main models have been proposed. Scientists have attempted to observe chloroplast replication via electron microscopy since the 1970s. The results of the microscopy experiments led to the idea that chloroplast DNA replicates using a double displacement loop (D-loop). As the D-loop moves through the circular DNA, it adopts a theta intermediary form, also known as a Cairns replication intermediate, and completes replication with a rolling circle mechanism. Replication starts at specific points of origin. Multiple replication forks open up, allowing replication machinery to replicate the DNA. As replication continues, the forks grow and eventually converge. The new cpDNA structures separate, creating daughter cpDNA chromosomes.
In addition to the early microscopy experiments, this model is also supported by the amounts of deamination seen in cpDNA. Deamination occurs when an amino group is lost and is a mutation that often results in base changes. When adenine is deaminated, it becomes hypoxanthine (H). Hypoxanthine can bind to cytosine, and when the HC base pair is replicated, it becomes a GC (thus, an A → G base change).
In cpDNA, there are several A → G deamination gradients. DNA becomes susceptible to deamination events when it is single stranded. When replication forks form, the strand not being copied is single stranded, and thus at risk for A → G deamination. Therefore, gradients in deamination indicate that replication forks were most likely present and the direction that they initially opened (the highest gradient is most likely nearest the start site because it was single stranded for the longest amount of time). This mechanism is still the leading theory today; however, a second theory suggests that most cpDNA is actually linear and replicates through homologous recombination. It further contends that only a minority of the genetic material is kept in circular chromosomes while the rest is in branched, linear, or other complex structures. | 0 | Theoretical and Fundamental Chemistry |
This rule is derived from the fact that, perhaps coincidentally, for the most common chemical elements in neutral organic compounds (hydrogen, carbon, nitrogen, oxygen, silicon, phosphorus, sulfur, and the halogens), elements with even numbered nominal masses form even numbers of covalent bonds, while elements with odd numbered nominal masses form odd numbers of covalent bonds, with the exception of nitrogen, which has a nominal (or integer) mass of 14, but has a valency of 3.
The nitrogen rule is only true for neutral structures in which all of the atoms in the molecule have a number of covalent bonds equal to their standard valency (counting each sigma bond and pi bond as a separate covalent bond for the purposes of the calculation). Therefore, the rule is typically only applied to the molecular ion signal in the mass spectrum.
Mass spectrometry generally operates by measuring the mass of ions. If the measured ion is generated by creating or breaking a single covalent bond (such as protonating an amine to form an ammonium center or removing a hydride from a molecule to leave a positively charged ion) then the nitrogen rule becomes reversed (odd numbered masses indicate even numbers of nitrogens and vice versa). However, for each consecutive covalent bond that is broken or formed, the nitrogen rule again reverses.
Therefore, a more rigorous definition of the nitrogen rule for organic compounds containing exclusively hydrogen, carbon, nitrogen, oxygen, silicon, phosphorus, sulfur, and the halogens would be as follows:
An even nominal mass indicates that a net even number of covalent bonds have been broken or formed and an even number of nitrogen atoms are present, or that a net odd number of covalent bonds have been broken or formed and an odd number of nitrogen atoms are present. An odd nominal mass indicates that a net even number of covalent bonds have been broken or formed and an odd number of nitrogen atoms are present, or that a net odd number of covalent bonds have been broken or formed and an even number of nitrogen atoms are present.
Inorganic molecules do not necessarily follow the rule. For example, the nitrogen oxides NO and NO have an odd number of nitrogens but even masses of 30 and 46, respectively. | 0 | Theoretical and Fundamental Chemistry |
Scintillons have been extensively purified from L. polyedra by centrifugation, and these purified scintillon preparations contain luciferase and luciferin binding protein as the only detectable protein components. The amount of luciferase, LBP and luciferin all vary over the course of a daily (circadian) period, as do the number of scintillons in the cell. These observations suggest that the circadian control of bioluminescence involves a daily synthesis and degradation of luciferase and LBP. When synthesized, these two proteins aggregate together and migrate to the vacuole membrane where LBP binds luciferin and the scintillons acquires an ability to produce light upon stimulation. | 1 | Applied and Interdisciplinary Chemistry |
Al-Si-Cu-Mg alloys form Al5FeSi- plate like intermetallic phases like -Al8Fe2Si, Al2Cu, etc. The size and morphology of these intermetallic phases in these alloys control the mechanical properties of these alloys, especially strength and ductility. The size of these phases depends on the secondary dendrite arm spacing, as well as the Si content of the alloy, of the primary phase in the micro structure. | 1 | Applied and Interdisciplinary Chemistry |
Mixed layer dynamics are quite complicated; however, in some regions some simplifications are possible. The wind-driven horizontal transport in the mixed layer is approximately described by Ekman Layer dynamics in which vertical diffusion of momentum balances the Coriolis effect and wind stress. This Ekman transport is superimposed on geostrophic flow associated with horizontal gradients of density. | 1 | Applied and Interdisciplinary Chemistry |
E. coli produces a second protein responsible for degradation of (p)ppGpp, SpoT. When the amino acid balance in the cell is restored, (p)ppGpp is hydrolyzed by SpoT and returned to a more energetically favorable state. This protein also has the capacity to synthesize (p)ppGpp, and seems to be the primary synthase under certain conditions of stress. Most other bacteria encode a single protein that is responsible for both synthesis and degradation of (p)ppGpp, generally homologs of SpoT. | 1 | Applied and Interdisciplinary Chemistry |
The Superstack was built by Inco Limited (and later purchased by Vale) at an estimated cost of 25 million dollars. Construction on the structure was underway during the Sudbury tornado of August 20, 1970; the structure swayed heavily in the wind, but remained standing and suffered only minor damage. Six workers were on top of the construction platform when the storm hit, and all survived. The same day was the final day of construction on the stack, with the construction fully completed by the evening of August 21, 1970.
The stack entered into full operation in 1972. From the date of its completion until the Ekibastuz GRES-2 chimney was constructed in 1987, it was the world's tallest smokestack. Between the years 1972–75 it was the tallest freestanding structure in Canada.
Prior to the construction of the Superstack, the waste gases contributed to severe local ecological damage. The Copper Cliff smelter was already home to some of the world's tallest stacks, including two chimneys constructed in 1928-29 and 1936. However, these proved to be insufficient and compounded by open coke beds in the early to mid-20th century and logging for fuel, an inevitable near-total loss of native vegetation occurred. Of particular interest to geologists are the now exposed rocky outcrops, which have been permanently stained charcoal black, first by the pollution wafting over the decades from the roasting yards, then by the acid rain in a layer which penetrates up to three inches into the once pink-grey granite.
The Superstack was built to disperse sulphur gases and other byproducts of the smelting process away from the city of Sudbury. It did this by placing the gases high in the air, where they normally blew right past the city on the prevailing winds. As a result, these gases can be detected in the atmosphere around Greater Sudbury in a radius of the Inco plant. During the 1970s and 80s, the sulphur dioxide plume formed a permanent, opaque, cloud-like formation running across the entire horizon as seen from a distance. Periodic inversions would cause the plume to fall into the city.
Construction of the Superstack was followed by an environmental reclamation project which has included rehabilitation of existing landscapes and selected water bodies such as Lake Ramsey. An ambitious regreening plan has seen over three million new trees planted within the Greater Sudbury area. In 1992, Inco and the city were given an award by the United Nations in honour of their environmental rehabilitation programmes.
On November 3, 2014, Vale announced that they may decide to stop using the stack, following a $1 billion project to reduce emissions by 85% that negates the need for the stack. If no other use for it is found, Vale may decommission the superstack, demolish it, and replace it with a much smaller chimney. In 2017, Vale announced plans to decommission the Superstack upon the construction of two smaller, more energy efficient stacks. On July 28, 2020, Vale updated that news, stating that the stack at its Copper Cliff Complex had been taken out of service. It would remain on "hot standby" for about two months while the replacement flue connections were tested but the stack would then be demolished over the years. | 1 | Applied and Interdisciplinary Chemistry |
Chemical gradients are sensed through multiple transmembrane receptors, called methyl-accepting chemotaxis proteins (MCPs), which vary in the molecules that they detect. Thousands of MCP receptors are known to be encoded across the bacterial kingdom. These receptors may bind attractants or repellents directly or indirectly through interaction with proteins of periplasmatic space. The signals from these receptors are transmitted across the plasma membrane into the cytosol, where Che proteins are activated. The Che proteins alter the tumbling frequency, and alter the receptors. | 1 | Applied and Interdisciplinary Chemistry |
The Strecker degradation is a chemical reaction which converts an α-amino acid into an aldehyde containing the side chain, by way of an imine intermediate. It is named after Adolph Strecker, a German chemist.
The original observation by Strecker involved the use of alloxan as the oxidant in the first step, followed by hydrolysis:
The reaction can take place using a variety of organic and inorganic reagents. | 0 | Theoretical and Fundamental Chemistry |
Bioasphalt is an asphalt alternative made from non-petroleum based renewable resources.
These sources include sugar, molasses and rice, corn and potato starches, natural tree and gum resins, natural latex rubber and vegetable oils, lignin, cellulose, palm oil waste, coconut waste, peanut oil waste, canola oil waste, dried sewerage effluent and so on. Bitumen can also be made from waste vacuum tower bottoms produced in the process of cleaning used motor oils, which are normally burned or dumped into land fills.
Non-petroleum based bitumen binders can be colored, which can reduce the temperatures of road surfaces and reduce the Urban heat islands. | 0 | Theoretical and Fundamental Chemistry |
With regard to permanent teeth, there is insufficient evidence to support the use of RMGIC as long term restorations in permanent teeth. Despite the low number of randomised control trials, a meta- analysis review by Bezerra et al. [2009] reported significantly fewer carious lesions on the margins of glass ionomer restorations in permanent teeth after six years as compared to amalgam restorations. In addition, adhesive ability and longevity of GIC from a clinical standpoint can be best studied with restoration of non- carious cervical lesions. A systematic review shows GIC has higher retention rates than resin composite in follow up periods of up to 5 years. Unfortunately, reviews for Class II restorations in permanent teeth with glass ionomer cement are scarce with high bias or short study periods. However, a study [2003] of the compressive strength and the fluoride release was done on 15 commercial fluoride- releasing restorative materials. A negative linear correlation was found between the compressive strength and fluoride release (r=0.7741), i.e., restorative materials with high fluoride release have lower mechanical properties. | 0 | Theoretical and Fundamental Chemistry |
Jai Pal Mittal is an elected fellow the Indian National Science Academy, National Academy of Sciences, India, The World Academy of Sciences, the Indian Academy of Sciences and the Maharashtra Academy of Sciences. He is a recipient of two awards, Professor T. R. Seshadri 70th Birthday Commemoration Medal in 1994 and the Golden Jubilee Commemoration Medal in 2001, from the Indian National Science Academy. A winner of 1964 Fulbright scholarship and 2002 Humboldt Research Award, Mittal has received the Senior JSPS Award, National Academy of Sciences, India N. R. Dhar Memorial Medal, Goyal Gold Medal and the Indian Science Congress Association Platinum Jubilee Award. The Government of India awarded him the civilian award of Padma Shri in 2003. | 0 | Theoretical and Fundamental Chemistry |
The activated complexes do not follow a Boltzmann distribution of energies, but an "equilibrium constant" can still be derived from the distribution they do follow. The equilibrium constant K for the quasi-equilibrium can be written as
So, the chemical activity of the transition state AB is
Therefore, the rate equation for the production of product is
where the rate constant k is given by
Here, k is directly proportional to the frequency of the vibrational mode responsible for converting the activated complex to the product; the frequency of this vibrational mode is . Every vibration does not necessarily lead to the formation of product, so a proportionality constant , referred to as the transmission coefficient, is introduced to account for this effect. So k can be rewritten as
For the equilibrium constant K, statistical mechanics leads to a temperature dependent expression given as
Combining the new expressions for k and K, a new rate constant expression can be written, which is given as
Since, by definition, ΔG = ΔH –TΔS, the rate constant expression can be expanded, to give an alternative form of the Eyring equation:
For correct dimensionality, the equation needs to have an extra factor of (c) for reactions that are not unimolecular:
where c is the standard concentration 1 mol⋅L and m is the molecularity. | 0 | Theoretical and Fundamental Chemistry |
In February 2018, 3M settled a lawsuit for $850 million related to contaminated drinking water in Minnesota. | 0 | Theoretical and Fundamental Chemistry |
Further works from Wöhler:
* Lehrbuch der Chemie, Dresden, 1825, 4 vols,
* Grundriss der Anorganischen Chemie, Berlin, 1830,
* Grundriss der Chemie, Berlin, 1837–1858 [http://nbn-resolving.de/urn:nbn:de:hbz:061:2-29177 Vol.1&2 Digital edition ] by the University and State Library Düsseldorf
* [https://books.google.com/books/about/W%C3%B6hler_s_Grundriss_der_organischen_chem.html?id=e-s-AAAAYAAJ Grundriss der Organischen Chemie], Berlin, 1840
* Praktische Übungen in der Chemischen Analyse, Berlin, 1854,
* Early Recollections of a Chemist, 1875
* [https://link.springer.com/journal/11583/volumes-and-issues Nuovo Cimento, 1855-1868 Vol. 1-28] | 1 | Applied and Interdisciplinary Chemistry |
Giovanni Aldini, Galvanis nephew, continued his uncles work after Luigi Galvani died in 1798. In 1803, Aldini performed a famous public demonstration of the electro-stimulation technique of deceased limbs on the corpse of an executed criminal George Foster at Newgate in London. The Newgate Calendar describes what happened when the galvanic process was used on the body:
Galvani has been called the father of electrophysiology. The debate between Galvani and Volta "would result in the creation of electrophysiology, electromagnetism, electrochemistry and the electric battery." | 0 | Theoretical and Fundamental Chemistry |
Note that Sides 1 and 2 are no longer in osmotic equilibrium (i.e. the total osmolytes on each side are not the same)
In vivo, ion balance does equilibriate at the proportions that would be predicted by the Gibbs–Donnan model, because the cell cannot tolerate the attendant large influx of water. This is balanced by instating a functionally impermeant cation, Na, extracellularly to counter the anionic protein. Na does cross the membrane via leak channels (the permeability is approximately 1/10 that of K, the most permeant ion) but, as per the pump-leak model, it is extruded by the Na/K-ATPase. | 0 | Theoretical and Fundamental Chemistry |
Although the native biological role of APP is of obvious interest to Alzheimers research, thorough understanding has remained elusive. Experimental models of Alzheimers disease are commonly used by researchers to gain better understandings about the biological function of APP in disease pathology and progression. | 1 | Applied and Interdisciplinary Chemistry |
From 1875 to 1920 American steel production grew from 380,000 tons to 60 million tons annually, making the U.S. the world leader. The annual growth rates in steel 1870–1913 were 7.0% for the US; 1.0% for Britain; 6.0% for Germany; and 4.3% for France, Belgium, and Russia, the other major producers. This explosive American growth rested on solid technological foundations and the continuous rapid expansion of urban infrastructures, office buildings, factories, railroads, bridges and other sectors that increasingly demanded steel. The use of steel in automobiles and household appliances came in the 20th century.
Some key elements in the growth of steel production included the easy availability of iron ore, and coal. Iron ore of fair quality was abundant in the eastern states, but the Lake Superior region contained huge deposits of exceedingly rich ore; the Marquette Iron Range was discovered in 1844; operations began in 1846. Other ranges were opened by 1910, including the Menominee, Gogebic, Vermilion, Cuyuna, and, greatest of all, (in 1892) the Mesabi range in Minnesota. This iron ore was shipped through the Great Lakes to ports such as Chicago, Detroit, Cleveland, Erie and Buffalo for shipment by rail to the steel mills. Abundant coal was available in Pennsylvania, West Virginia, and Ohio. Manpower was short. Few Native Americans wanted to work in the mills, but immigrants from Britain and Germany (and later from Eastern Europe) arrived in great numbers.
In 1869 iron was already a major industry, accounting for 6.6% of manufacturing employment and 7.8% of manufacturing output. By then the central figure was Andrew Carnegie, who made Pittsburgh the center of the industry. He sold his operations to US Steel in 1901, which became the world's largest steel corporation for decades.
In the 1880s, the transition from wrought iron puddling to mass-produced Bessemer steel greatly increased worker productivity. Highly skilled workers remained essential, but the average level of skill declined. Nevertheless, steelworkers earned much more than ironworkers despite their fewer skills. Workers in an integrated, synchronized mass production environment wielded greater strategic power, for the greater cost of mistakes bolstered workers' status. The experience demonstrated that the new technology did not decrease worker bargaining leverage by creating an interchangeable, unskilled workforce. | 1 | Applied and Interdisciplinary Chemistry |
The Schultz theory (after D. L. Schultz) is applicable only for very high energy solids. Again, it is similar to the theories of Owens, Wendt, Fowkes, and Wu, but is designed for a situation where conventional measurement required for those theories is impossible. In the class of solids with sufficiently high surface energy, most liquids wet the surface completely with a contact angle of zero degrees, and thus no useful data can be gathered. The Schultz theory and procedure calls to deposit a sessile drop of probe liquid on the solid surface in question, but this is all done while the system is submerged in yet another liquid, rather than being done in the open air. As a result, the higher “atmospheric” pressure due to the surrounding liquid causes the probe liquid droplet to compress so that there is a measurable contact angle. | 0 | Theoretical and Fundamental Chemistry |
Careful storage is needed when handling sodium hydroxide for use, especially bulk volumes. Following proper NaOH storage guidelines and maintaining worker/environment safety is always recommended given the chemical's burn hazard.
Sodium hydroxide is often stored in bottles for small-scale laboratory use, within intermediate bulk containers (medium volume containers) for cargo handling and transport, or within large stationary storage tanks with volumes up to 100,000 gallons for manufacturing or waste water plants with extensive NaOH use. Common materials that are compatible with sodium hydroxide and often utilized for NaOH storage include: polyethylene (HDPE, usual, XLPE, less common), carbon steel, polyvinyl chloride (PVC), stainless steel, and fiberglass reinforced plastic (FRP, with a resistant liner).
Sodium hydroxide must be stored in airtight containers to preserve its normality as it will absorb water from the atmosphere. | 0 | Theoretical and Fundamental Chemistry |
In science, and most specifically chemistry, the accepted value denotes a value of a substance accepted by almost all scientists and the experimental value denotes the value of a substance's properties found in a localized lab. | 0 | Theoretical and Fundamental Chemistry |
* Protein Data Bank (PDB): repository for protein sequence and structural information
* UniProt: provides sequence and functional information
* Structural Classification of Proteins (SCOP Classifications): hierarchical-based approach
* Class, Architecture, Topology and Homologous superfamily (CATH): hierarchical-based approach | 1 | Applied and Interdisciplinary Chemistry |
In addition to lipid rafts, cholesterol can also interact with proteins that possess lipid-binding domains, such as certain types of sterol-sensing domains or cholesterol recognition/interaction amino acid consensus (CRAC) motifs. These interactions can affect protein conformation, stability, and function, thereby influencing various cellular processes like signal transduction, membrane trafficking, and enzyme activity. As a signaling lipid, cholesterol may act as a ligand. | 1 | Applied and Interdisciplinary Chemistry |
LIBS is one of several analytical techniques that can be deployed in the field as opposed to pure laboratory techniques e.g. spark OES. , recent research on LIBS focuses on compact and (man-)portable systems. Some industrial applications of LIBS include the detection of material mix-ups, analysis of inclusions in steel, analysis of slags in secondary metallurgy, analysis of combustion processes, and high-speed identification of scrap pieces for material-specific recycling tasks. Armed with data analysis techniques, this technique is being extended to pharmaceutical samples. | 0 | Theoretical and Fundamental Chemistry |
A similar phenomenon occurs in many other systems. Another example is vibrational modes in a liquid. Each molecule of the liquid has vibrational modes, and the vibrational frequency is influenced by the positions of nearby molecules. However, if the nearby molecules reorient and move around fast enough, the vibration will essentially occur at an averaged frequency, and therefore have a smaller linewidth. For example, simulations suggest that the OH stretch vibration linewidth in liquid water is 30% smaller than it would be without this motional narrowing effect. | 0 | Theoretical and Fundamental Chemistry |
Otto Berg (23 November 1873 – 1939) was a German scientist. He is one of the scientists credited with discovering rhenium, the last element to be discovered having a stable isotope. | 1 | Applied and Interdisciplinary Chemistry |
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