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Two general types of instruments exist: filter fluorometers that use filters to isolate the incident light and fluorescent light and spectrofluorometers that use diffraction grating monochromators to isolate the incident light and fluorescent light.
Both types use the following scheme: the light from an excitation source passes through a filter or monochromator, and strikes the sample. A proportion of the incident light is absorbed by the sample, and some of the molecules in the sample fluoresce. The fluorescent light is emitted in all directions. Some of this fluorescent light passes through a second filter or monochromator and reaches a detector, which is usually placed at 90° to the incident light beam to minimize the risk of transmitted or reflected incident light reaching the detector.
Various light sources may be used as excitation sources, including lasers, LED, and lamps; xenon arcs and mercury-vapor lamps in particular. A laser only emits light of high irradiance at a very narrow wavelength interval, typically under 0.01 nm, which makes an excitation monochromator or filter unnecessary. The disadvantage of this method is that the wavelength of a laser cannot be changed by much. A mercury vapor lamp is a line lamp, meaning it emits light near peak wavelengths. By contrast, a xenon arc has a continuous emission spectrum with nearly constant intensity in the range from 300-800 nm and a sufficient irradiance for measurements down to just above 200 nm.
Filters and/or monochromators may be used in fluorimeters. A monochromator transmits light of an adjustable wavelength with an adjustable tolerance. The most common type of monochromator utilizes a diffraction grating, that is, collimated light illuminates a grating and exits with a different angle depending on the wavelength. The monochromator can then be adjusted to select which wavelengths to transmit. For allowing anisotropy measurements, the addition of two polarization filters is necessary: One after the excitation monochromator or filter, and one before the emission monochromator or filter.
As mentioned before, the fluorescence is most often measured at a 90° angle relative to the excitation light. This geometry is used instead of placing the sensor at the line of the excitation light at a 180° angle in order to avoid interference of the transmitted excitation light. No monochromator is perfect and it will transmit some stray light, that is, light with other wavelengths than the targeted. An ideal monochromator would only transmit light in the specified range and have a high wavelength-independent transmission. When measuring at a 90° angle, only the light scattered by the sample causes stray light. This results in a better signal-to-noise ratio, and lowers the detection limit by approximately a factor 10000, when compared to the 180° geometry. Furthermore, the fluorescence can also be measured from the front, which is often done for turbid or opaque samples
The detector can either be single-channeled or multichanneled. The single-channeled detector can only detect the intensity of one wavelength at a time, while the multichanneled one detects the intensity of all wavelengths simultaneously, making the emission monochromator or filter unnecessary.
The most versatile fluorimeters with dual monochromators and a continuous excitation light source can record both an excitation spectrum and a fluorescence spectrum. When measuring fluorescence spectra, the wavelength of the excitation light is kept constant, preferably at a wavelength of high absorption, and the emission monochromator scans the spectrum. For measuring excitation spectra, the wavelength passing through the emission filter or monochromator is kept constant and the excitation monochromator is scanning. The excitation spectrum generally is identical to the absorption spectrum as the fluorescence intensity is proportional to the absorption. | 0 | Theoretical and Fundamental Chemistry |
Soil is composed of living organisms, water, carbonates, carbon containing material, decomposing matter and much more. To determine how much one of these soil components make up the entire soil mass, the LOI procedure is implemented. Initially, the researcher will take the mass of the sample prior to LOI and then place the sample into a heating device. Depending on what the researcher is trying to determine in the soil, the temperature of the device can be set to the corresponding temperature. The soil sample is kept at this temperature for an extended period of time after which it is removed and allowed to cool down before re-weighing the sample. The amount of mass lost after the LOI treatment is equal to the mass of the component the researcher is trying to determine. The typical set of materials needed to use LOI include: a high precision mass balance, a drying oven, temperature controlled furnace, preheated crucibles and soil sample from the location of interest.
There are many ways to properly utilize loss on ignition for scientific research. A soil sample left overnight in a drying oven at 100 °C would have its water content completely evaporated by morning. This could allow the researchers to determine the amount of water initially in the soil sample and its porosity by comparing the change in weight of the sample before and after the evaporation. This new weight of the sample is called the dry weight and its previous weight is called the wet weight. | 0 | Theoretical and Fundamental Chemistry |
Levocetirizine is used for allergic rhinitis. This includes allergy symptoms such as watery eyes, runny nose, sneezing, hives, and itching. | 0 | Theoretical and Fundamental Chemistry |
The ethyl ester of propionic acid (1) was brominated and then converted to the Wittig reagent using triphenylphosphine. Aldehyde 6 was obtained from allyl alcohol (4) by protection as the tert-butyldiphenylsilyl ether (5) followed by ozonolysis. Wittig reagent 3 and aldehyde 6 reacted in a Wittig reaction to give unsaturated ester 7, which was deprotected to give dienophile 8 (Scheme 1, compound 1). | 0 | Theoretical and Fundamental Chemistry |
Materials with broad absorption bands are being applied in pigments, dyes and optical filters. Titanium dioxide, zinc oxide and chromophores are applied as UV absorbers and reflectors in sunscreen. | 0 | Theoretical and Fundamental Chemistry |
Hydrogen bond-assisted supramolecular assembly is the process of assembling small organic molecules to form large supramolecular structures by non-covalent hydrogen bonding interactions. The directionality, reversibility, and strong bonding nature of hydrogen bond make it an attractive and useful approach in supramolecular assembly. Functional groups such as carboxylic acids, ureas, amines, and amides are commonly used to assemble higher order structures upon hydrogen bonding.
Hydrogen bond play an essential role in the assembly of secondary and tertiary structures of large biomolecules. DNA double helix is formed by hydrogen bonding between nucleobases: adenine and thymine forms two hydrogen bonds, while guanine and cytosine forms three hydrogen bonds (Figure "Hydrogen bonds in (a) DNA duplex formation"). Another prominent example of hydrogen bond-assisted assembly in nature is the formation of protein secondary structures. Both the α-helix and β-sheet are formed through hydrogen bonding between the amide hydrogen and the amide carbonyl oxygen (Figure "Hydrogen bonds in (b) protein β-sheet structure").
In supramolecular chemistry, hydrogen bonds have been broadly applied to crystal engineering, molecular recognition, and catalysis. Hydrogen bonds are among the mostly used synthons in bottom-up approach to engineering molecular interactions in crystals. Representative hydrogen bond patterns for supramolecular assembly is shown in Figure "Representative hydrogen bond patterns in supramolecular assembly". A 1: 1 mixture of cyanuric acid and melamine forms crystal with a highly dense hydrogen-bonding network. This supramolecular aggregates has been used as templates to engineering other crystal structures. | 0 | Theoretical and Fundamental Chemistry |
Primer walking is a method to determine the sequence of DNA up to the 1.3–7.0 kb range whereas chromosome walking is used to produce the clones of already known sequences of the gene. Too long fragments cannot be sequenced in a single sequence read using the chain termination method. This method works by dividing the long sequence into several consecutive short ones. The DNA of interest may be a plasmid insert, a PCR product or a fragment representing a gap when sequencing a genome. The term "primer walking" is used where the main aim is to sequence the genome. The term "chromosome walking" is used instead when the sequence is known but there is no clone of a gene. For example, the gene for a disease may be located near a specific marker such as an RFLP on the sequence. Chromosome walking is a technique used to clone a gene (e.g., disease gene) from its known closest markers (e.g., known gene) and hence is used in moderate modifications in cloning and sequencing projects in plants, fungi, and animals. To put it another way, it's utilized to find, isolate, and clone a specific sequence existing near the gene to be mapped. Libraries of large fragments, mainly bacterial artificial chromosome libraries, are mostly used in genomic projects. To identify the desired colony and to select a particular clone the library is screened first with a desired probe. After screening, the clone is overlapped with the probe and overlapping fragments are mapped. These fragments are then used as a new probe (short DNA fragments obtained from the 3′ or 5′ ends of clones) to identify other clones. A library approximately consists of 96 clones and each clone contains a different insert. Probe one identifies λ1 and λ2 as it overlaps them . Probe two derived from λ2 clones is used to identify λ3, and so on. Orientation of the clones is determined by restriction mapping of the clones. Thus, new chromosomal regions present in the vicinity of a gene could be identified. Chromosome walking is time-consuming, and chromosome landing is the method of choice for gene identification. This method necessitates the discovery of a marker that is firmly related to the mutant locus.
The fragment is first sequenced as if it were a shorter fragment. Sequencing is performed from each end using either universal primers or specifically designed ones. This should identify the first 1000 or so bases. In order to completely sequence the region of interest, design and synthesis of new primers (complementary to the final 20 bases of the known sequence) is necessary to obtain contiguous sequence information. | 1 | Applied and Interdisciplinary Chemistry |
The following example illustrates the potential of the photoacoustic technique: In the early 1970s, Patel and co-workers measured the temporal variation of the concentration of nitric oxide in the stratosphere at an altitude of 28 km with a balloon-borne photoacoustic detector. These measurements provided crucial data bearing on the problem of ozone depletion by man-made nitric oxide emission. Some of the early work relied on development of the RG theory by Rosencwaig and Gersho. | 0 | Theoretical and Fundamental Chemistry |
Examples of hydrated minerals include:
* silicates (, )
** phyllosilicates, clay minerals "commonly found on Earth as weathering products of rocks or in hydrothermal systems"
***chlorite
*** muscovite
* non-silicates
** oxides (, , , etc.) and oxy-hydroxides
*** brucite,
*** goethite, FeO(OH)
** carbonates (, etc.)
*** hydromagnesite,
*** ikaite, , the unstable hexahydrate form of calcium carbonate
** hydroxylated minerals
*** saponite
*** talc
** hydroxysulfides (mixed sulfides-hydroxides)
*** tochilinite, a hydroxysulfide or hydrated sulfide mineral of iron(II) and magnesium of chemical formula: <br />, also written , in IMA notation
*** valleriite, an uncommon sulfide-hydroxide mineral of iron(II) and copper of chemical formula: <br />, or | 0 | Theoretical and Fundamental Chemistry |
δ-Aminolevulinic acid (also dALA, δ-ALA, 5ALA or 5-aminolevulinic acid), an endogenous non-proteinogenic amino acid, is the first compound in the porphyrin synthesis pathway, the pathway that leads to heme in mammals, as well as chlorophyll in plants.
5ALA is used in photodynamic detection and surgery of cancer. | 1 | Applied and Interdisciplinary Chemistry |
Permittivity is typically associated with dielectric materials, however metals are described as having an effective permittivity, with real relative permittivity equal to one. In the high-frequency region, which extends from radio frequencies to the far infrared and terahertz region, the plasma frequency of the electron gas is much greater than the electromagnetic propagation frequency, so the refractive index n of a metal is very nearly a purely imaginary number. In the low frequency regime, the effective relative permittivity is also almost purely imaginary: It has a very large imaginary value related to the conductivity and a comparatively insignificant real-value. | 0 | Theoretical and Fundamental Chemistry |
Spice, spiciness, or spicity, symbol τ, is a term in oceanography referring to variations in the temperature and salinity of seawater over space or time, whose combined effects leave the water's density unchanged. For a given spice, any change in temperature is offset by a change in salinity to maintain unchanged density. An increase in temperature decreases density, but an increase in salinity increases density. Such density-compensated thermohaline variability is ubiquitous in the upper ocean. Warmer, saltier water is more spicy while cooler, less salty water is more minty. For a density ratio of 1, all the thermohaline variability is spice, and there are no density fluctuations. | 0 | Theoretical and Fundamental Chemistry |
Dichloromethane, . There is a rotation axis which passes through the carbon atom and the midpoints between the two hydrogen atoms and the two chlorine atoms. Define the z axis as co-linear with the axis, the plane as containing and the plane as containing . A rotation operation permutes the two hydrogen atoms and the two chlorine atoms. Reflection in the plane permutes the hydrogen atoms while reflection in the plane permutes the chlorine atoms. The four symmetry operations , , and form the point group . Note that if any two operations are carried out in succession the result is the same as if a single operation of the group had been performed.
Methane, . In addition to the proper rotations of order 2 and 3 there are three mutually perpendicular axes which pass half-way between the C-H bonds and six mirror planes. Note that | 0 | Theoretical and Fundamental Chemistry |
The ancestry of each present day cell presumably traces back, in an unbroken lineage for over 3 billion years to the origin of life. It is not actually cells that are immortal but multi-generational cell lineages. The immortality of a cell lineage depends on the maintenance of cell division potential. This potential may be lost in any particular lineage because of cell damage, terminal differentiation as occurs in nerve cells, or programmed cell death (apoptosis) during development. Maintenance of cell division potential over successive generations depends on the avoidance and the accurate repair of cellular damage, particularly DNA damage. In sexual organisms, continuity of the germline depends on the effectiveness of processes for avoiding DNA damage and repairing those DNA damages that do occur. Sexual processes in eukaryotes, as well as in prokaryotes, provide an opportunity for effective repair of DNA damages in the germ line by homologous recombination. | 1 | Applied and Interdisciplinary Chemistry |
Consider the inexact differential form, This must be inexact by considering going to the point . If we first increase and then increase , then that corresponds to first integrating over and then over . Integrating over first contributes and then integrating over contributes . Thus, along the first path we get a value of 2. However, along the second path we get a value of . We can make an exact differential by multiplying it by , yielding . And so is an exact differential. | 0 | Theoretical and Fundamental Chemistry |
Nucleofection is a method to transfer substrates into mammalian cells so far considered difficult or even impossible to transfect. Examples for such substrates are nucleic acids, like the DNA of an isolated gene cloned into a plasmid, or small interfering RNA (siRNA) for knocking down expression of a specific endogenous gene.
Primary cells, for example stem cells, especially fall into this category, although many other cell lines are also difficult to transfect. Primary cells are freshly isolated from body tissue and thus cells are unchanged, closely resembling the in-vivo situation, and are therefore of particular relevance for medical research purposes. In contrast, cell lines have often been cultured for decades and may significantly differ from their origin. | 1 | Applied and Interdisciplinary Chemistry |
Amides () take the suffix "-amide", or "-carboxamide" if the carbon in the amide group cannot be included in the main chain. The prefix form is "carbamoyl-". e.g., methanamide, ethanamide.
Amides that have additional substituents on the nitrogen are treated similarly to the case of amines: they are ordered alphabetically with the location prefix N: is N,N-dimethylmethanamide, is N,N-dimethylethanamide. | 0 | Theoretical and Fundamental Chemistry |
DNA testing has been used to establish the right of succession to British titles.
Cases:
* Baron Moynihan
* Pringle baronets | 1 | Applied and Interdisciplinary Chemistry |
Liposomes are structures which consist of at least one lipid bilayer surrounding an aqueous core. This hydrophobic/hydrophilic composition is particularly useful for drug delivery as these carriers can accommodate a number of drugs of varying lipophilicity. Disadvantages associated with using liposomes as drug carriers involve poor control over drug release. Drugs which have high membrane-permeability can readily leak from the carrier, while optimization of in vivo stability can cause drug release by diffusion to be a slow and inefficient process. Much of the current research involving liposomes is focused on improving the delivery of anticancer drugs such as doxorubicin and paclitaxel. | 1 | Applied and Interdisciplinary Chemistry |
A goniometer is an instrument that either measures an angle or allows an object to be rotated to a precise angular position. The term goniometry derives from two Greek words, γωνία (gōnía) angle and μέτρον (métron) measure. The protractor is a commonly used type in the fields of mechanics, engineering, and geometry.
The first known description of a goniometer, based on the astrolabe, was by Gemma Frisius in 1538. | 0 | Theoretical and Fundamental Chemistry |
An ambident nucleophile is one that can attack from two or more places, resulting in two or more products. For example, the thiocyanate ion (SCN) may attack from either the sulfur or the nitrogen. For this reason, the S2 reaction of an alkyl halide with SCN often leads to a mixture of an alkyl thiocyanate (R-SCN) and an alkyl isothiocyanate (R-NCS). Similar considerations apply in the Kolbe nitrile synthesis. | 0 | Theoretical and Fundamental Chemistry |
Keith Stewartson and C. R. Illingworth, independently introduced in 1949, a transformation that extends the Howarth–Dorodnitsyn transformation to compressible flows. The transformation reads as
where is the streamwise coordinate, is the normal coordinate, denotes the sound speed and denotes the pressure. For ideal gas, the transformation is defined as
where is the specific heat ratio. | 1 | Applied and Interdisciplinary Chemistry |
The Dean number (De) is a dimensionless group in fluid mechanics, which occurs in the study of flow in curved pipes and channels. It is named after the British scientist W. R. Dean, who was the first to provide a theoretical solution of the fluid
motion through curved pipes for laminar flow by using a perturbation procedure from a Poiseuille flow in a straight pipe to a flow in a pipe with very small curvature. | 1 | Applied and Interdisciplinary Chemistry |
Modafinil is used off-label as an adjunctive treatment (i.e., in combination therapy) for acute depressive phase in bipolar disorder. The depressive phase of bipolar disorder may feature excessive sleepiness and fatigue. Adjunctive treatment with modafinil can be used as an augmentation for the main treatment to increase its effect and is safe and effective, especially for people who do not respond well to standard antidepressants. Modafinil does not significantly increase the risk of mood switch to mania or suicide attempts in people with bipolar disorder. Modafinil may also have cognitive benefits in people with bipolar disorder who are in a remission state.
Whereas modafinil and armodafinil are approved for narcolepsy, they have been repurposed as adjunctive treatments to alleviate symptoms of acute depressive phase in people with bipolar disorder. Drug repurposing in psychiatry is a strategy for discovering new uses for drugs that have already been approved or tested in clinical trials for other illnesses. As such, drug repurposing is a rapid, cost-effective, and reduced-risk strategy for the development of new treatment options for psychiatric disorders. 2021 meta-analysis concluded that add-on modafinil and armodafinil were more effective than placebo on response to treatment, clinical remission, and reduction in depressive symptoms, with only minor side effects, but the effect sizes are small and the quality of evidence is therefore low, limiting the clinical relevance of the evidence. Very low rates of mood swing (a change in mood from one extreme to another) have been observed with modafinil and armodafinil in depressive phase of bipolar disorder. | 0 | Theoretical and Fundamental Chemistry |
The visual cycle is a circular enzymatic pathway, which is the front-end of phototransduction. It regenerates 11-cis-retinal. For example, the visual cycle of mammalian rod cells is as follows:
#all-trans-retinyl ester + HO → 11-cis-retinol + fatty acid; RPE65 isomerohydrolases;
#11-cis-retinol + NAD → 11-cis-retinal + NADH + H; 11-cis-retinol dehydrogenases;
#11-cis-retinal + aporhodopsin → rhodopsin + HO; forms Schiff base linkage to lysine, -CH=NH-;
#rhodopsin + hν → metarhodopsin II (i.e., 11-cis photoisomerizes to all-trans):
#:(rhodopsin + hν → photorhodopsin → bathorhodopsin → lumirhodopsin → metarhodopsin I → metarhodopsin II);
#metarhodopsin II + HO → aporhodopsin + all-trans-retinal;
#all-trans-retinal + NADPH + H → all-trans-retinol + NADP; all-trans-retinol dehydrogenases;
#all-trans-retinol + fatty acid → all-trans-retinyl ester + HO; lecithin retinol acyltransferases (LRATs).
Steps 3, 4, 5, and 6 occur in rod cell outer segments; Steps 1, 2, and 7 occur in retinal pigment epithelium (RPE) cells.
RPE65 isomerohydrolases are homologous with beta-carotene monooxygenases; the homologous ninaB enzyme in Drosophila has both retinal-forming carotenoid-oxygenase activity and all-trans to 11-cis isomerase activity. | 1 | Applied and Interdisciplinary Chemistry |
Dideoxynucleotides are used in sequencing. These nucleoside triphosphates possess a non-canonical sugar, dideoxyribose, which lacks the 3 hydroxyl group normally present in DNA and therefore cannot bond with the next base. The lack of the 3 hydroxyl group terminates the chain reaction as the DNA polymerases mistake it for a regular deoxyribonucleotide. Another chain-terminating analogue that lacks a 3' hydroxyl and mimics adenosine is called cordycepin. Cordycepin is an anticancer drug that targets RNA replication. Another analogue in sequencing is a nucleobase analogue, 7-deaza-GTP and is used to sequence CG rich regions, instead 7-deaza-ATP is called tubercidin, an antibiotic. | 1 | Applied and Interdisciplinary Chemistry |
Initial measurements of position specific isotope enrichments were measured using isotope ratio mass spectrometry in which sites on a molecule were first degraded to , the was captured and purified, and then the CO was measured for its isotope composition on an Isotope Ratio Mass Spectrometer (IRMS). Py-GC-MS was also used in these experiments to degrade molecules even further and characterize their intramolecular isotopic distributions. Both GC-MS and LC-MS are capable of characterizing position specific isotope enrichments in isotopically labelled molecules. In these molecules, C is so abundant that it can be seen on a mass spectrometer with low sensitivity. The resolution of these instruments can distinguish two molecules with a 1 Dalton difference in their molecular masses; however, this difference could arise from the addition of many rare isotopes (O, C, H, etc.). For this reason, mass spectrometers using quadrupoles or time-of-flight detection techniques cannot be used for measuring position-specific enrichments at natural abundances. | 0 | Theoretical and Fundamental Chemistry |
Compounds like allicin and ajoene are responsible for the odor of garlic. Lenthionine contributes to the flavor of shiitake mushrooms. Volatile organosulfur compounds also contribute subtle flavor characteristics to wine, nuts, cheddar cheese, chocolate, coffee, and tropical fruit flavors. Many of these natural products also have important medicinal properties such as preventing platelet aggregation or fighting cancer.
Humans and other animals have an exquisitely sensitive sense of smell toward the odor of low-valent organosulfur compounds such as thiols, sulfides, and disulfides. Malodorous volatile thiols are protein-degradation products found in putrid food, so sensitive identification of these compounds is crucial to avoiding intoxication. Low-valent volatile sulfur compounds are also found in areas where oxygen levels in the air are low, posing a risk of suffocation.
Copper is required for the highly sensitive detection of certain volatile thiols and related organosulfur compounds by olfactory receptors in mice. Whether humans, too, require copper for sensitive detection of thiols is not yet known. | 0 | Theoretical and Fundamental Chemistry |
Phototrophs () are organisms that carry out photon capture to produce complex organic compounds (e.g. carbohydrates) and acquire energy. They use the energy from light to carry out various cellular metabolic processes. It is a common misconception that phototrophs are obligatorily photosynthetic. Many, but not all, phototrophs often photosynthesize: they anabolically convert carbon dioxide into organic material to be utilized structurally, functionally, or as a source for later catabolic processes (e.g. in the form of starches, sugars and fats). All phototrophs either use electron transport chains or direct proton pumping to establish an electrochemical gradient which is utilized by ATP synthase, to provide the molecular energy currency for the cell. Phototrophs can be either autotrophs or heterotrophs. If their electron and hydrogen donors are inorganic compounds (e.g., , as in some purple sulfur bacteria, or , as in some green sulfur bacteria) they can be also called lithotrophs, and so, some photoautotrophs are also called photolithoautotrophs. Examples of phototroph organisms are Rhodobacter capsulatus, Chromatium, and Chlorobium. | 0 | Theoretical and Fundamental Chemistry |
In chemical equations, radicals are frequently denoted by a dot placed immediately to the right of the atomic symbol or molecular formula as follows:
Radical reaction mechanisms use single-headed arrows to depict the movement of single electrons:
The homolytic cleavage of the breaking bond is drawn with a "fish-hook" arrow to distinguish from the usual movement of two electrons depicted by a standard curly arrow. The second electron of the breaking bond also moves to pair up with the attacking radical electron.
Radicals also take part in radical addition and radical substitution as reactive intermediates. Chain reactions involving radicals can usually be divided into three distinct processes. These are initiation, propagation, and termination.
*Initiation reactions are those that result in a net increase in the number of radicals. They may involve the formation of radicals from stable species as in Reaction 1 above or they may involve reactions of radicals with stable species to form more radicals.
*Propagation reactions are those reactions involving radicals in which the total number of radicals remains the same.
*Termination reactions are those reactions resulting in a net decrease in the number of radicals. Typically two radicals combine to form a more stable species, for example:
*:2 Cl → Cl | 1 | Applied and Interdisciplinary Chemistry |
Before installing a check dam, engineers inspect the site. Standard practices call for the drainage area to be ten acres or less. The waterway should be on a slope of no more than 50% and should have a minimum depth to bedrock of . Check dams are often used in natural or constructed channels or swales. They should never be placed in live streams unless approved by appropriate local, state and/or federal authorities. | 1 | Applied and Interdisciplinary Chemistry |
The Voigt profile (named after Woldemar Voigt) is a probability distribution given by a convolution of a Cauchy-Lorentz distribution and a Gaussian distribution. It is often used in analyzing data from spectroscopy or diffraction. | 0 | Theoretical and Fundamental Chemistry |
This process was developed by the National Smelting Company at Avonmouth Docks, England, in order to increase production, increase efficiency, and decrease labour and maintenance costs. L. J. Derham proposed using a spray of molten lead droplets to rapidly cool and absorb the zinc vapour, despite the high concentration of carbon dioxide. The mixture is then cooled, where the zinc separates from the lead. The first plant using this design opened up in 1950. One of the advantages of this process is that it can co-produce lead bullion and copper dross. In 1990, it accounted for 12% of the world's zinc production.
The process starts by charging solid sinter and heated coke into the top of the blast furnace. Preheated air at is blown into the bottom of the furnace. Zinc vapour and sulfides leave through the top and enter the condenser. Slag and lead collect at the bottom of the furnace and are tapped off regularly. The zinc is scrubbed from the vapour in the condenser via liquid lead. The liquid zinc is separated from the lead in the cooling circuit. Approximately of lead are required each year for this process, however this process recovers 25% more lead from the starting ores than other processes. | 1 | Applied and Interdisciplinary Chemistry |
On 23 February 1841, a meeting was convened to take into consideration the formation of a Chemical Society. The Provisional Committee appointed for carrying that object into effect invited a number of gentlemen engaged in the practice and pursuit of chemistry to become original members. The following 77 communicated their written assent: | 1 | Applied and Interdisciplinary Chemistry |
Frohring took a job on the loading dock at Telling-Belle Vernon Dairy, the largest dairy in Ohio. Eight months later, he was offered an opportunity to run fat tests in the Telling-Belle Vernon labs for Henry J. Gerstenberger, MD, the medical director of Babies Dispensary and Childrens Hospital (later, Rainbow Babies & Childrens Hospital), a pediatric hospital in Cleveland. Dr. Gerstenberger, with the assistance of Harold O. Ruh, MD, was investigating the possibility of developing a dairy formula to supplement or replace maternal milk for infants. | 0 | Theoretical and Fundamental Chemistry |
In polymer chemistry and polymer physics, the Flory–Fox equation is a simple empirical formula that relates molecular weight to the glass transition temperature of a polymer system. The equation was first proposed in 1950 by Paul J. Flory and Thomas G. Fox while at Cornell University. Their work on the subject overturned the previously held theory that the glass transition temperature was the temperature at which viscosity reached a maximum. Instead, they demonstrated that the glass transition temperature is the temperature at which the free space available for molecular motions achieved a minimum value. While its accuracy is usually limited to samples of narrow range molecular weight distributions, it serves as a good starting point for more complex structure-property relationships.
Recent molecular simulations have demonstrated that while the functional form of the Flory-Fox relation holds for a wide range of molecular architectures (linear chain, bottlebrush, star, and ring polymers), however, the central free-volume argument of the Flory-Fox relation does not hold since branched polymers, despite having more free ends, form materials of higher density and glass transition temperature increases. | 0 | Theoretical and Fundamental Chemistry |
The electron transport chain of green sulfur bacteria—such as is present in the model organism Chlorobaculum tepidum—uses the reaction center bacteriochlorophyll pair, P840. When light is absorbed by the reaction center, P840 enters an excited state with a large negative reduction potential, and so readily donates the electron to bacteriochlorophyll 663, which passes it on down an electron transport chain. The electron is transferred through a series of electron carriers and complexes until it is used to reduce NAD to NADH. P840 regeneration is accomplished with the oxidation of a sulfide ion from hydrogen sulfide (or of hydrogen or ferrous iron) by cytochrome c. | 0 | Theoretical and Fundamental Chemistry |
A Morpholino, also known as a Morpholino oligomer and as a phosphorodiamidate Morpholino oligomer (PMO), is a type of oligomer molecule (colloquially, an oligo) used in molecular biology to modify gene expression. Its molecular structure contains DNA bases attached to a backbone of methylenemorpholine rings linked through phosphorodiamidate groups. Morpholinos block access of other molecules to small (~25 base) specific sequences of the base-pairing surfaces of ribonucleic acid (RNA). Morpholinos are used as research tools for reverse genetics by knocking down gene function.
This article discusses only the Morpholino antisense oligomers, which are nucleic acid analogs. The word "Morpholino" can occur in other chemical names, referring to chemicals containing a six-membered morpholine ring. To help avoid confusion with other morpholine-containing molecules, when describing oligos "Morpholino" is often capitalized as a trade name, but this usage is not consistent across scientific literature. Morpholino oligos are sometimes referred to as PMO (for phosphorodiamidate morpholino oligomer), especially in medical literature. Vivo-Morpholinos and PPMO are modified forms of Morpholinos with chemical groups covalently attached to facilitate entry into cells.
Gene knockdown is achieved by reducing the expression of a particular gene in a cell. In the case of protein-coding genes, this usually leads to a reduction in the quantity of the corresponding protein in the cell. Knocking down gene expression is a method for learning about the function of a particular protein; in a similar manner, causing a specific exon to be spliced out of the RNA transcript encoding a protein can help to determine the function of the protein moiety encoded by that exon or can sometimes knock down the protein activity altogether. These molecules have been applied to studies in several model organisms, including mice, zebrafish, frogs and sea urchins. Morpholinos can also modify the splicing of pre-mRNA or inhibit the maturation and activity of miRNA. Techniques for targeting Morpholinos to RNAs and delivering Morpholinos into cells have recently been reviewed in a journal article and in book form.
Morpholinos are in development as pharmaceutical therapeutics targeted against pathogenic organisms such as bacteria or viruses and genetic diseases. A Morpholino-based drug eteplirsen from Sarepta Therapeutics received accelerated approval from the US Food and Drug Administration in September 2016 for the treatment of some mutations causing Duchenne muscular dystrophy, although the approval process was mired in controversy. Other Morpholino-based drugs golodirsen, viltolarsen, and casimersen (also for Duchenne muscular dystrophy) were approved by the FDA in 2019–2021. | 1 | Applied and Interdisciplinary Chemistry |
CoQ in the pure form is a crystalline powder insoluble in water. Absorption as a pharmacological substance follows the same process as that of lipids; the uptake mechanism appears to be similar to that of vitamin E, another lipid-soluble nutrient. This process in the human body involves secretion into the small intestine of pancreatic enzymes and bile, which facilitates emulsification and micelle formation required for absorption of lipophilic substances. Food intake (and the presence of lipids) stimulates bodily biliary excretion of bile acids and greatly enhances absorption of CoQ. Exogenous CoQ is absorbed from the small intestine and is best absorbed if taken with a meal. Serum concentration of CoQ in fed condition is higher than in fasting conditions. | 1 | Applied and Interdisciplinary Chemistry |
Chemical tags have been tailored for imaging technologies more so than fluorescent proteins because chemical tags can localize photosensitizers closer to the target proteins. Proteins can then be labeled and detected with imaging such as super-resolution microscopy, Ca-imaging, pH sensing, hydrogen peroxide detection, chromophore assisted light inactivation, and multi-photon light microscopy. In vivo imaging studies in live animals have been performed for the first time with the use of a monomeric protein derived from the bacterial haloalkane dehalogenase known as the Halo-tag. The Halo-tag covalently links to its ligand and allows for better expression of soluble proteins. | 1 | Applied and Interdisciplinary Chemistry |
The measured full SPR curves (x-axis: angle, y-axis: reflected light intensity) can be transcribed into sensograms (x-axis: time, y-axis: selected parameter such as peak minimum, light intensity, peak width). The sensograms can be fitted using binding models to obtain kinetic parameters including on- and off-rates and affinity. The full SPR curves are used to fit Fresnel equations to obtain thickness and refractive index of the layers. Also due to the ability of scanning the whole SPR curve, MP-SPR is able to separate bulk effect and analyte binding from each other using parameters of the curve.
While QCM-D measures wet mass, MP-SPR and other optical methods measure dry mass, which enables analysis of water content of nanocellulose films. | 0 | Theoretical and Fundamental Chemistry |
The Societys wholly owned publishing subsidiary, Portland Press, publishes books, a magazine, The Biochemist', and several print and online academic journals:
*Biochemical Journal
*Biochemical Society Symposium (online only)
*Biochemical Society Transactions
*Cell Signalling Biology
*Clinical Science
*Essays in Biochemistry
*Bioscience Reports
The Societys flagship publication, the Biochemical Journal', celebrated its centenary in 2006 with the launch of a free online archive back to its first issue in 1906. | 1 | Applied and Interdisciplinary Chemistry |
EWM research has suggested possible applications in the excitation of optical masers, high intensity light sources for communications, spacecraft propulsion, joining difficult materials such as quartz, and generation of high power radio-frequency pulses. The most promising applications of EWM are as a detonator, light source, and for the production of nanoparticles. | 0 | Theoretical and Fundamental Chemistry |
3-Methylfentanyl was also reported by media as the identity of the anaesthetic "gas" Kolokol-1 delivered as an aerosol during the Moscow theater hostage crisis in 2002 in which many hostages died from accidental overdoses, 3-methylfentanyl was later ruled out as the primary agent used. The opiate antidote naloxone was on-hand to treat the victims of the crisis, but, whether due to their incarceration, lack of food, or water, or sleep, or due to the novel nature of the still-unconfirmed compound used, acute symptoms continued to develop, resulting in many fatalities despite the administration of naloxone. | 1 | Applied and Interdisciplinary Chemistry |
When a molecule or atom in the ground state (S) absorbs light, one electron is excited to a higher orbital level. This electron maintains its spin according to the spin selection rule; other transitions would violate the law of conservation of angular momentum. The excitation to a higher singlet state can be from HOMO to LUMO or to a higher orbital, so that singlet excitation states S, S, S... at different energies are possible.
Kasha's rule stipulates that higher singlet states would quickly relax by radiationless decay or internal conversion (IC) to S. Thus, S is usually, but not always, the only relevant singlet excited state. This excited state S can further relax to S by IC, but also by an allowed radiative transition from S to S that emits a photon; this process is called fluorescence.
Alternatively, it is possible for the excited state S to undergo spin inversion and to generate a triplet excited state T having two unpaired electrons with the same spin. This violation of the spin selection rule is possible by intersystem crossing (ISC) of the vibrational and electronic levels of S and T. According to Hund's rule of maximum multiplicity, this T state would be somewhat more stable than S.
This triplet state can relax to the ground state S by radiationless IC or by a radiation pathway called phosphorescence. This process implies a change of electronic spin, which is forbidden by spin selection rules, making phosphorescence (from T to S) much slower than fluorescence (from S to S). Thus, triplet states generally have longer lifetimes than singlet states. These transitions are usually summarized in a state energy diagram or Jablonski diagram, the paradigm of molecular photochemistry.
These excited species, either S or T, have a half-empty low-energy orbital, and are consequently more oxidizing than the ground state. But at the same time, they have an electron in a high-energy orbital, and are thus more reducing. In general, excited species are prone to participate in electron transfer processes. | 0 | Theoretical and Fundamental Chemistry |
Green Infrastructure as a term did not appear until the early 1990s, although ideas of Green Infrastructure had been used long before that. The first coined use of the term was seen in a 1994 report by Buddy MacKay, chair of the Florida Greenways Commission, to Florida governor Lawton Chiles about a Green Infrastructure project undertaken in 1991: Florida Greenways Project. MacKay states, "Just as we carefully plan the infrastructure our communities need to support the people who live there—the roads, water and electricity—so must we begin to plan and manage Florida’s green infrastructure”. | 1 | Applied and Interdisciplinary Chemistry |
As a catalyst, ArMs have three advantages,
# thanks to the development in molecular biology, it is quite easy to generate a library of ArM mutants which has a size up to 10. Using proper selection method, the ArM has a large potential to gain unique catalytic properties.
# ArMs are proteins, it can have both hydrophilic and hydrophobic surface in the aqueous solution. Anchoring the artificial cofactor which is not easily dissolve in water would help it function in aqueous phase. In some structure, the hydrophobic cavity would protect some labile bond (like many carbene or nitrene-metal complex in Arnold ArMs).
# The backbone itself in ArM is a asymmetric environment. In some cases, the enantioselective synthesis can be tuned by changing one or two amino acid residues around the metal catalytic center.
So far, ArMs can catalyze a lot of chemical reactions, such as: allylic alkylation, allylic amination, aldol reaction, alcohol oxidation, C-H activation, click reaction, catechol oxidation, reduction, cyclopropanation, Diels-Alder reaction, epoxidation, epoxide ring opening, Friedel-Crafts alkylation, hydrogenation, hydroformylation, Heck reaction, metathesis, Michael addition, nitrite reduction, NO reduction, Suzuki reaction, Si-H insertion, polymerization (atom transfer radical polymerization). | 0 | Theoretical and Fundamental Chemistry |
Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids. Crystallography is a fundamental subject in the fields of materials science and solid-state physics (condensed matter physics). The word crystallography is derived from the Ancient Greek word (; "clear ice, rock-crystal"), and (; "to write"). In July 2012, the United Nations recognised the importance of the science of crystallography by proclaiming that 2014 would be the International Year of Crystallography.
Before the development of X-ray diffraction crystallography (see below), the study of crystals was based on physical measurements of their geometry using a goniometer. This involved measuring the angles of crystal faces relative to each other and to theoretical reference axes (crystallographic axes), and establishing the symmetry of the crystal in question. The position in 3D space of each crystal face is plotted on a stereographic net such as a Wulff net or Lambert net. The pole to each face is plotted on the net. Each point is labelled with its Miller index. The final plot allows the symmetry of the crystal to be established.
Crystallographic methods depend mainly on analysis of the diffraction patterns of a sample targeted by a beam of some type. X-rays are most commonly used; other beams used include electrons or neutrons. Crystallographers often explicitly state the type of beam used, as in the terms X-ray crystallography, neutron diffraction and electron diffraction. These three types of radiation interact with the specimen in different ways.
* X-rays interact with the spatial distribution of electrons in the sample.
* Neutrons are scattered by the atomic nuclei through the strong nuclear forces, but in addition, the magnetic moment of neutrons is non-zero. They are therefore also scattered by magnetic fields. When neutrons are scattered from hydrogen-containing materials, they produce diffraction patterns with high noise levels. However, the material can sometimes be treated to substitute deuterium for hydrogen. Because of these different forms of interaction, the three types of radiation are suitable for different crystallographic studies.
* Electrons are charged particles and therefore interact with the total charge distribution of both the atomic nuclei and the electrons of the sample.
It is hard to focus x-rays or neutrons, but since electrons are charged they can be focused and are used in electron microscope to produce magnified images. There are many ways that transmission electron microscopy and related techniques such as scanning transmission electron microscopy, high-resolution electron microscopy can be used to obtain images with in many cases atomic resolution from which crystallographic information can be obtained. There are also other methods such as low-energy electron diffraction, low-energy electron microscopy and reflection high-energy electron diffraction which can be used to obtain crystallographic information about surfaces. | 0 | Theoretical and Fundamental Chemistry |
The high enantio- and regiocontrol afforded by phosphinooxazoline ligands has fuelled research into their use for asymmetric hydrogenation. Iridium complexes incorporating phosphinooxazoline ligands have been shown to be effective for classic hydrogenation using H, with ruthenium and palladium catalysts having also been investigated for transfer hydrogenation. In addition to theoretical studies, the structural and kinetic properties of Ir-PHOX complexes have been investigated to better understand their behaviour as hydrogenation catalysts. | 0 | Theoretical and Fundamental Chemistry |
As a reference, molten sodium chloride, table salt has a melting point (m.p.) of 801 °C (1474 °F). A variety of eutectic mixtures have been developed with lower melting points: | 1 | Applied and Interdisciplinary Chemistry |
Two types of convective heat transfer may be distinguished:
* Free or natural convection: when fluid motion is caused by buoyancy forces that result from the density variations due to variations of thermal ±temperature in the fluid. In the absence of an internal source, when the fluid is in contact with a hot surface, its molecules separate and scatter, causing the fluid to be less dense. As a consequence, the fluid is displaced while the cooler fluid gets denser and the fluid sinks. Thus, the hotter volume transfers heat towards the cooler volume of that fluid. Familiar examples are the upward flow of air due to a fire or hot object and the circulation of water in a pot that is heated from below.
* Forced convection: when a fluid is forced to flow over the surface by an internal source such as fans, by stirring, and pumps, creating an artificially induced convection current.
In many real-life applications (e.g. heat losses at solar central receivers or cooling of photovoltaic panels), natural and forced convection occur at the same time (mixed convection).
Internal and external flow can also classify convection. Internal flow occurs when a fluid is enclosed by a solid boundary such as when flowing through a pipe. An external flow occurs when a fluid extends indefinitely without encountering a solid surface. Both of these types of convection, either natural or forced, can be internal or external because they are independent of each other. The bulk temperature, or the average fluid temperature, is a convenient reference point for evaluating properties related to convective heat transfer, particularly in applications related to flow in pipes and ducts.
Further classification can be made depending on the smoothness and undulations of the solid surfaces. Not all surfaces are smooth, though a bulk of the available information deals with smooth surfaces. Wavy irregular surfaces are commonly encountered in heat transfer devices which include solar collectors, regenerative heat exchangers, and underground energy storage systems. They have a significant role to play in the heat transfer processes in these applications. Since they bring in an added complexity due to the undulations in the surfaces, they need to be tackled with mathematical finesse through elegant simplification techniques. Also, they do affect the flow and heat transfer characteristics, thereby behaving differently from straight smooth surfaces.
For a visual experience of natural convection, a glass filled with hot water and some red food dye may be placed inside a fish tank with cold, clear water. The convection currents of the red liquid may be seen to rise and fall in different regions, then eventually settle, illustrating the process as heat gradients are dissipated. | 0 | Theoretical and Fundamental Chemistry |
Sulfide is incorporated into cysteine, catalyzed by O-acetylserine (thiol)lyase, with O-acetylserine as substrate. The synthesis of O-acetylserine is catalyzed by serine acetyltransferase and together with O-acetylserine (thiol)lyase it is associated as enzyme complex named cysteine synthase.
The formation of cysteine is the direct coupling step between sulfur (sulfur metabolism) and nitrogen assimilation in plants. This differs from the process in yeast, where sulfide must be incorporated first in homocysteine then converted in two steps to cysteine.
Cysteine is sulfur donor for the synthesis of methionine, the major other sulfur-containing amino acid present in plants. This happens through the transsulfuration pathway and the methylation of homocysteine.
Both cysteine and methionine are sulfur-containing amino acids and are of great significance in the structure, conformation and function of proteins and enzymes, but high levels of these amino acids may also be present in seed storage proteins. The thiol groups of the cysteine residues in proteins can be oxidized resulting in disulfide bridges with other cysteine side chains (and form cystine) and/or linkage of polypeptides.
Disulfide bridges (disulfide bonds) make an important contribution to the structure of proteins. The thiol groups are also of great importance in substrate binding of enzymes, in metal-sulfur clusters in proteins (e.g. ferredoxins) and in regulatory proteins (e.g. thioredoxins). | 1 | Applied and Interdisciplinary Chemistry |
Multispectral imaging can be employed for investigation of paintings and other works of art. The painting is irradiated by ultraviolet, visible and infrared rays and the reflected radiation is recorded in a camera sensitive in this region of the spectrum. The image can also be registered using the transmitted instead of reflected radiation. In special cases the painting can be irradiated by UV, VIS or IR rays and the fluorescence of pigments or varnishes can be registered.
Multispectral analysis has assisted in the interpretation of ancient papyri, such as those found at Herculaneum, by imaging the fragments in the infrared range (1000 nm). Often, the text on the documents appears to the naked eye as black ink on black paper. At 1000 nm, the difference in how paper and ink reflect infrared light makes the text clearly readable. It has also been used to image the Archimedes palimpsest by imaging the parchment leaves in bandwidths from 365–870 nm, and then using advanced digital image processing techniques to reveal the undertext with Archimedes' work. Multispectral imaging has been used in a Mellon Foundation project at Yale University to compare inks in medieval English manuscripts.
Multispectral imaging has also been used to examine discolorations and stains on old books and manuscripts. Comparing the "spectral fingerprint" of a stain to the characteristics of known chemical substances can make it possible to identify the stain. This technique has been used to examine medical and alchemical texts, seeking hints about the activities of early chemists and the possible chemical substances they may have used in their experiments. Like a cook spilling flour or vinegar on a cookbook, an early chemist might have left tangible evidence on the pages of the ingredients used to make medicines. | 0 | Theoretical and Fundamental Chemistry |
A materials oscilloscope is a time-resolved synchrotron
high-energy X-ray technique to study rapid phase composition and microstructural related changes in a polycrystalline sample. Such device has been developed for in-situ studies of specimens undergoing physical thermo-mechanical simulation. | 0 | Theoretical and Fundamental Chemistry |
Shingling was a stage in the production of bar iron or steel, in the finery and puddling processes. As with many ironmaking terms, this is derived from the French - cinglage.
The product of the finery was a bloom or loop (from old Frankish luppa or lopp, meaning a shapeless mass); that of the puddling furnace was a puddled ball. In each case, this needed to be consolidated by hammering it into a more regular shape. This was done manually with heavy hammers; later by a waterwheel or steam powered hammers, leading to modern power hammers. The result was an oblong-shaped iron product similar in appearance to shingles used on roofs. In the finery, this was part of the work of the finer; during puddling, it was done by a special workman called the shingler. The iron (or steel) then had to be further shaped (drawn out) under the hammer or rolled in a rolling mill to produce a bar. In more recent times, the process was carried out using mechanical jaws to squeeze the puddled ball into shape. | 1 | Applied and Interdisciplinary Chemistry |
The foundations of Feigls work on spot analysis were the works of Hugo Schiff (the earliest publication about "spot test" was Shiffs detection of uric acid in 1859) and of Christian Friedrich Schonberg and Friedrich Goppelsröder on capillary analysis.
On the occasion of Feigl's 70th birthday the Chemical Society of Midland sponsored a symposium in 1952, attended by 500 scientists from 24 countries, in which all plenary sessions were related to spot tests.
The test uses the qualitative characteristics of colored compounds to account for performed chemical reactions. This technique has been used to develop new quantification methods using modern technology. | 0 | Theoretical and Fundamental Chemistry |
According to Landau,
He later adds:
After an example, he concludes (with used to represent volume viscosity): | 1 | Applied and Interdisciplinary Chemistry |
For any coordination number above 2 more than one coordination geometry is possible. For example four coordinate coordination compounds can be tetrahedral, square planar, square pyramidal or see-saw shaped. The polyhedral symbol is used to describe the geometry. A configuration index is determined from the positions of the ligands and together with the polyhedral symbol is placed at the beginning of the name. For example in the complex (SP-4-3)-(acetonitrile)dichlorido(pyridine)platinum(II) the (SP-4-3) at the beginning of the name describes a square planar geometry, 4 coordinate with a configuration index of 3 indicating the position of the ligands around the central atom. For more detail see polyhedral symbol. | 0 | Theoretical and Fundamental Chemistry |
MDCs are utilized in seawater desalination by primarily acting as a precursor treatment for electrodialysis (ED) due to the inefficiency in salinity removal due to biofouling and membrane scaling by the complex ion composition. Studies show that efficacy of MDC systems diminish over 5000 hours due to membrane scaling such as calcium and potassium accumulation, increasing ohmic resistance and reducing ion exchange through the membrane. However, by utilizing MDCs as a precursor treatment for electrodialysis, results show that system time is reduced by 25% and energy expenditure decreases by 45.3%. Reduction in external resistance increases desalination efficiency to as high as 74%, as demonstrated in upflow microbial desalination cells (UMDC), but increased membrane scaling on the ion exchange membranes by calcium and magnesium accumulation, resulting in a higher internal ohmic resistance and decrease in overall desalination of seawater. With the application of an osmotic MFC (OsMFC) in conjunction with the UMDC as an initial pretreatment of biosolid removal and desalination, 85% of oxygen demand and approximately 97% of salts was reduced after secondary treatment. Subsequent treatment by traditional BES systems such as electrodialysis can function as a more effective system for desalination, provisioning energy demands by the output energy obtained from the MDC pretreatment. | 0 | Theoretical and Fundamental Chemistry |
During differentiation, pluripotent cells make a number of developmental decisions to generate first the three germ layers (ectoderm, mesoderm and endoderm) of the embryo and intermediate progenitors, followed by subsequent decisions or check points, giving rise to all the bodys mature tissues. The differentiation process can be modeled as sequence of binary decisions based on probabilistic or stochastic models. Developmental biology and embryology provides the basic knowledge of the cell types differentiation through mutation analysis, lineage tracing, embryo micro-manipulation and gene expression studies. Cell differentiation and tissue organogenesis involve a limited set of developmental signaling pathways. It is thus possible to direct cell fate by controlling cell decisions through extracellular signaling, mimicking developmental signals. | 1 | Applied and Interdisciplinary Chemistry |
These methods are referred to as reverse genetics. Reverse genetics is an approach to discover the function of a gene by analyzing the phenotypic effects of specific gene sequences obtained by DNA sequencing | 1 | Applied and Interdisciplinary Chemistry |
The PELP1 protein encodes a protein of 1130 amino acids, and exhibits both cytoplasmic and nuclear localization depending on the tissue. PELP1 lacks known enzymatic activity and functions as a scaffolding protein. It contains 10 NR-interacting boxes (LXXLL motifs) and functions as a coregulator of several nuclear receptors via its LXXLL motifs including ESR1, ESR2, ERR-alpha, PR, GR, AR, and RXR. PELP1 also functions as a coregulator of several other transcription factors, including AP1, SP1, NFkB, STAT3, and FHL2.
PELP1 has a histone binding domain and interacts with chromatin-modifying complexes, including CBP/p300, histone deacetylase 2, histones, SUMO2, lysine-specific demethylase 1 (KDM1), PRMT6, and CARM1. PELP1 also interacts with cell cycle regulators such as pRb. E2F1, and p53.
PELP1 is phosphorylated by hormonal and growth factor signals. PELP1 phosphorylation status is also influenced by cell cycle progression, and it is a substrate of CDKs. Further, PELP1 is phosphorylated by DNA damage induced kinases (ATM, ATR, DNA-PKcs). | 1 | Applied and Interdisciplinary Chemistry |
*Order "For Merit to the Fatherland", 4th class
*Two Orders of Lenin
*Order of the Patriotic War, 2nd class
*Order of the Red Star
*Order of the October Revolution
*Two Orders of the Red Banner of Labour
*Medal of Zhukov
* USSR State Prize | 0 | Theoretical and Fundamental Chemistry |
* U.S. Commissioner of Corporations. Report on the Steel Industry (1913).
* Warne, Colston E. ed. The Steel Strike of 1919 (1963), primary and secondary documents | 1 | Applied and Interdisciplinary Chemistry |
An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment. The ability to exhibit aerobic respiration may yield benefits to the aerobic organism, as aerobic respiration yields more energy than anaerobic respiration. Energy production of the cell involves the synthesis of ATP by an enzyme called ATP synthase. In aerobic respiration, ATP synthase is coupled with an electron transport chain in which oxygen acts as a terminal electron acceptor. In July 2020, marine biologists reported that aerobic microorganisms (mainly), in "quasi-suspended animation", were found in organically poor sediments, up to 101.5 million years old, 250 feet below the seafloor in the South Pacific Gyre (SPG) ("the deadest spot in the ocean"), and could be the longest-living life forms ever found. | 1 | Applied and Interdisciplinary Chemistry |
The trimerization of a part of a nitrile molecule and two parts of acetylene into pyridine is called Bönnemann cyclization. This modification of the Reppe synthesis can be activated either by heat or by light. While the thermal activation requires high pressures and temperatures, the photoinduced cycloaddition proceeds at ambient conditions with CoCp(cod) (Cp = cyclopentadienyl, cod = 1,5-cyclooctadiene) as a catalyst, and can be performed even in water. A series of pyridine derivatives can be produced in this way. When using acetonitrile as the nitrile, 2-methylpyridine is obtained, which can be dealkylated to pyridine. | 0 | Theoretical and Fundamental Chemistry |
GaAs can be used for various transistor types:
* Metal–semiconductor field-effect transistor (MESFET)
* High-electron-mobility transistor (HEMT)
* Junction field-effect transistor (JFET)
* Heterojunction bipolar transistor (HBT)
* Metal–oxide–semiconductor field-effect transistor (MOSFET)
The HBT can be used in integrated injection logic (IL).
The earliest GaAs logic gate used Buffered FET Logic (BFL).
From to 1995 the main logic families used were:
* Source-coupled FET logic (SCFL) fastest and most complex, (used by TriQuint & Vitesse)
* Capacitor–diode FET logic (CDFL) (used by Cray for Cray-3)
* Direct-coupled FET logic (DCFL) simplest and lowest power (used by Vitesse for VLSI gate arrays) | 0 | Theoretical and Fundamental Chemistry |
Redox reactions are normally strongly exothermic, and can make excellent candidates for thermometric titrations. In the classical determination of ferrous ion with permanganate, the reaction enthalpy is more than double that of a strong acid/strong base titration:ΔH =
−123.9 kJ/mol of Fe. The determination of hydrogen peroxide by permanganate titration is even more strongly exothermic at ΔH =
−149.6 kJ/mol HO | 0 | Theoretical and Fundamental Chemistry |
The Tsuji–Wilkinson decarbonylation proceeds under mild conditions and is highly stereospecific. In addition to aliphatic, aromatic, and α,β-unsaturated aldehydes, acyl nitriles and 1,2-diketones are also suitable substrates. Few methods exist for decarbonylation.
One illustrative application is the synthesis of the core nucleus of FR-900482. Note that the ester is unaffected by the rhodium reagent.
The Tsuji–Wilkinson decarbonylation is employed in the penultimate step of the synthesis of (–)-presilphiperfolan-8-ol. They comment “Of note in these final steps, separate reduction and oxidation steps proceeded in inferior yield in generating 38 (70% versus 93%), while the Rh(PPh)Cl operation proceeded smoothly when conducted on small scale (~15 mg). In total, the synthesis required 13 steps from commercial starting material, and ~15 mg of [(–)-presilphiperfolan-8-ol] has been prepared with spectral properties and optical rotations matching that of the natural isolate.” | 0 | Theoretical and Fundamental Chemistry |
Cyanobacteria are capable of natural genetic transformation. Natural genetic transformation is the genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous DNA from its surroundings. For bacterial transformation to take place, the recipient bacteria must be in a state of competence, which may occur in nature as a response to conditions such as starvation, high cell density or exposure to DNA damaging agents. In chromosomal transformation, homologous transforming DNA can be integrated into the recipient genome by homologous recombination, and this process appears to be an adaptation for repairing DNA damage. | 0 | Theoretical and Fundamental Chemistry |
With a regular income, Hahn was now able to contemplate marriage. In June 1911, while attending a conference in Stettin, Hahn met (1887–1968), a student at the Royal School of Art in Berlin. They saw each other again in Berlin, and became engaged in November 1912. On 22 March 1913 the couple married in Edith's native city of Stettin, where her father, Paul Ferdinand Junghans, was a high-ranking law officer and President of the City Parliament until his death in 1915. After a honeymoon at Punta San Vigilio on Lake Garda in Italy, they visited Vienna, and then Budapest, where they stayed with George de Hevesy.
Their only child, , was born on 9 April 1922. During World War II, he enlisted in the army in 1942, and served with distinction on the Eastern Front as a panzer commander. He lost an arm in combat. After the war he became a distinguished art historian and architectural researcher (at the Hertziana in Rome), known for his discoveries in the early Cistercian architecture of the 12th century. In August 1960, while on a study trip in France, Hanno died in a car accident, together with his wife and assistant Ilse Hahn née Pletz. They left a fourteen-year-old son, Dietrich Hahn.
In 1990, the for outstanding contributions to Italian art history was established in memory of Hanno and Ilse Hahn to support young and talented art historians. It is awarded biennially by the Bibliotheca Hertziana – Max Planck Institute for Art History in Rome. | 0 | Theoretical and Fundamental Chemistry |
Martha was born in Georgia, Vermont on February 13, 1870. She grew up in Easthampton, Massachusetts where she graduated high school. She earned her B.S. degree from Smith College in 1892. Prior to enrolling in graduate school at Yale University, she taught as a science teacher in New York and Massachusetts. She started graduate school in 1896 and graduated with her Ph.D. in chemistry in 1898. After completing her Ph.D., she continued working for her Ph.D. advisor, Andrew Gooch in the Kent Chemistry Laboratory for one year and then transferred to the Rhode Island Experiment Station where she worked as an assistant chemist in 1900. From 1901-1904, she went back to being a science teacher and taught chemistry and physics at Wilson College. In 1904, she also married Issac King Phelps, who was working as a chemistry instructor at Yale and George Washington University at the time. In 1908, the couple moved to Washington D.C. where Martha went to work for the Bureau of Standards as a chemistry researcher and Issac went to work for the U.S. Department of Agriculture. Martha ceased working as researcher in 1909. Martha was one of the first female scientists to be employed by the Bureau of Standards. After 1909, she began her activist work in women's education clubs until retirement. Martha and Issac lived in Washington D.C until 1923, until they moved to New Haven, Connecticut where Martha eventually died on March 15, 1933. | 0 | Theoretical and Fundamental Chemistry |
In 1911 M. Potter described how microbial conversions could create reducing power, and thus electric current. Twenty years later Cohen (1931) investigated the capacity of bacteria to produce an electrical flow and he noted that the main limitation is the small capacity of current generation in microorganisms. Berk and Canfield (1964) didnt build the first microbial fuel cell (MFC) until the 60s.
Currently, the investigation of bioelectrochemical reactors is increasing. These devices have real applications in fields like water treatment, energy production and storage, resources production, recycling and recovery. | 1 | Applied and Interdisciplinary Chemistry |
Although suffering from poor mechanical strength, some approach has been made to construct hydrogel fiber with textile methods. Also, the electrospun, meltspun, DIW method can produce hydrogel fiber structures at higher dimensions directly. | 0 | Theoretical and Fundamental Chemistry |
In surface science, a double layer (DL, also called an electrical double layer, EDL) is a structure that appears on the surface of an object when it is exposed to a fluid. The object might be a solid particle, a gas bubble, a liquid droplet, or a porous body. The DL refers to two parallel layers of charge surrounding the object. The first layer, the surface charge (either positive or negative), consists of ions which are adsorbed onto the object due to chemical interactions. The second layer is composed of ions attracted to the surface charge via the Coulomb force, electrically screening the first layer. This second layer is loosely associated with the object. It is made of free ions that move in the fluid under the influence of electric attraction and thermal motion rather than being firmly anchored. It is thus called the "diffuse layer".
Interfacial DLs are most apparent in systems with a large surface-area-to-volume ratio, such as a colloid or porous bodies with particles or pores (respectively) on the scale of micrometres to nanometres. However, DLs are important to other phenomena, such as the electrochemical behaviour of electrodes.
DLs play a fundamental role in many everyday substances. For instance, homogenized milk exists only because fat droplets are covered with a DL that prevents their coagulation into butter. DLs exist in practically all heterogeneous fluid-based systems, such as blood, paint, ink and ceramic and cement slurry.
The DL is closely related to electrokinetic phenomena and electroacoustic phenomena. | 0 | Theoretical and Fundamental Chemistry |
A helion (symbol h) is the nucleus of a helium atom, a doubly positively charged cation. The term helion is a portmanteau of helium and ion, and in practice refers specifically to the nucleus of the helium-3 isotope, consisting of two protons and one neutron. The nucleus of the other stable isotope of helium, helium-4, consisting of two protons and two neutrons, is called an alpha particle or an alpha for short.
This particle is the daughter product in the beta-minus decay of tritium, an isotope of hydrogen:
CODATA reports the mass of a helion particle as =
Helions are intermediate products in the proton–proton chain reaction in stellar fusion.
An antihelion is the antiparticle of a helion, consisting of two antiprotons and an antineutron. | 0 | Theoretical and Fundamental Chemistry |
Morpholine oleate is used in glazing wax which covers fruit. NMOR can be generated by the nitration of morpholine, causing its presence in waxed fruits.Health Canada, the Canadian governmental department of public health, has stated in 2002 that this does not pose a risk to human health.
Consumption of nitrate-rich diets is correlated with levels of salivary and urinary NMOR. The presence of NMOR can also be observed in gastric juices. | 0 | Theoretical and Fundamental Chemistry |
Marine primary production can be divided into new production from allochthonous nutrient inputs to the euphotic zone, and regenerated production from nutrient recycling in the surface waters. The total new production in the ocean roughly equates to the sinking flux of particulate organic matter to the deep ocean, about 4 × 10 tons of carbon annually. | 0 | Theoretical and Fundamental Chemistry |
Acetals, ketals, and aminals are reduced in the presence of hydrosilanes and acid. Site-selective reduction of acetals and ketals whose oxygens are inequivalent have been reported—the example below is used in a synthesis of Tamiflu.
Other functional groups that have been reduced with hydrosilanes include amides, and α,β-unsaturated esters enamines, imines, and azides. | 0 | Theoretical and Fundamental Chemistry |
Finally, this type of plot can readily be drawn to illustrate the effects of changing parameters in the acid-catalyzed nucleophilic addition to carbonyls. The example in Figure 4 demonstrates the effects of increasing the strength of the acid. In this case, the extent of protonation is the α-value in the Brønsted catalysis equation. The fact that the α-value remains unchanged explains the linearity of Brønsted plots for such a reaction.
Ultimately, the More O’Ferrall–Jencks plots have qualitative predictive and explanatory power regarding the effects of changing substituents and reaction conditions for a wide variety of reactions. | 0 | Theoretical and Fundamental Chemistry |
Alkyl tosylates are alkylating agents because tosylate is electron-withdrawing as well as a good leaving group. Tosylate is a pseudohalide. Toluenesulfonate esters undergo nucleophilic attack or elimination. Reduction of tosylate esters gives the hydrocarbon. Thus, tosylation followed by reduction allows for the deoxygenation of alcohols.
In a famous and illustrative use of tosylate, 2-norbornyl cation was displaced from the 7-norbornenyl tosylate. The elimination occurs 10 times faster than the solvolysis of anti-7-norbornyl p-toluenesulfonate.
Tosylates are also protecting group for alcohols. They are prepared by combining the alcohol with 4-toluenesulfonyl chloride, usually in an aprotic solvent, often pyridine. | 0 | Theoretical and Fundamental Chemistry |
Patricia Ana Matrai is a marine scientist known for her work on the cycling of sulfur. She is a senior research scientist at Bigelow Laboratory for Ocean Sciences. | 0 | Theoretical and Fundamental Chemistry |
STAT1 has been shown to interact with:
* BRCA1,
* C-jun,
* CD117,
* CREB-binding protein,
* Calcitriol receptor,
* Epidermal growth factor receptor,
* Fanconi anemia, complementation group C,
* GNB2L1,
* IFNAR2,
* IRF1,
* ISGF3G
* Interleukin 27 receptor, alpha subunit,
* MCM5,
* Mammalian target of rapamycin,
* PIAS1,
* PRKCD,
* PTK2,
* Protein kinase R,
* STAT2,
* STAT3,
* Src, and
* TRADD. | 1 | Applied and Interdisciplinary Chemistry |
The effect of crystal symmetry on misorientations is to reduce the fraction of the full orientation space necessary to uniquely represent all possible misorientation relationships. For example, cubic crystals (i.e. FCC) have 24 symmetrically related orientations. Each of these orientations is physically indistinguishable, though mathematically distinct. Therefore, the size of orientation space is reduced by a factor of 24. This defines the fundamental zone (FZ) for cubic symmetries. For the misorientation between two cubic crystallites, each possesses its 24 inherent symmetries. In addition, there exists a switching symmetry, defined by:
which recognizes the invariance of misorientation to direction; A→B or B→A. The fraction of the total orientation space in the cubic-cubic fundamental zone for misorientation is then given by:<br />
or 1/48 the volume of the cubic fundamental zone. This also has the effect of limiting the maximum unique misorientation angle to 62.8°<br />
<br />
Disorientation describes the misorientation with the smallest possible rotation angle out of all symmetrically equivalent misorientations that fall within the FZ (usually specified as having an axis in the standard stereographic triangle for cubics). Calculation of these variants involves application of crystal symmetry operators to each of the orientations during the calculation of misorientation.<br />
<br />
where O denotes one of the symmetry operators for the material. | 0 | Theoretical and Fundamental Chemistry |
The Secretin family are peptides that act as local hormones which regulate activity of G-protein coupled receptors. Most often found in the pancreas and the intestines. Secretin was discovered in 1902 by E. H. Starling. It was later linked to chemical regulation and was the first substance to be deemed a hormone.
#Secretin
#Glucagon
#Glicentin (GLI)
#Vasoactive intestinal peptide (VIP)
#Gastric inhibitory polypeptide (GIP) | 1 | Applied and Interdisciplinary Chemistry |
The numbers of electrons "donated" by some ligands depends on the geometry of the metal-ligand ensemble. An example of this complication is the M–NO entity. When this grouping is linear, the NO ligand is considered to be a three-electron ligand. When the M–NO subunit is strongly bent at N, the NO is treated as a pseudohalide and is thus a one electron (in the neutral counting approach). The situation is not very different from the η versus the η allyl. Another unusual ligand from the electron counting perspective is sulfur dioxide. | 0 | Theoretical and Fundamental Chemistry |
ERVs have been found to be associated to disease not only through disease-causing relations, but also through immunity. The frequency of ERVs in long terminal repeats (LTRs) likely correlates to viral adaptations to take advantage of immunity signaling pathways that promote viral transcription and replication. A study done in 2016 investigated the benefit of ancient viral DNA integrated into a host through gene regulation networks induced by interferons, a branch of innate immunity. These cytokines are first to respond to viral infection and are also important in immunosurveillance for malignant cells. ERVs are predicted to act as cis-regulatory elements, but much of the adaptive consequences of this for certain physiological functions is still unknown. There is data that supports the general role of ERVs in the regulation of human interferon response, specifically to interferon-gamma (IFNG). For example, interferon-stimulated genes were found to be greatly enriched with ERVs bound by signal transducer and activator of transcription 1 (STAT1) and/or Interferon regulatory factor (IRF1) in CD14+ macrophages.
HERVs also play various roles shaping the human innate immunity response, with some sequences activating the system and others suppressing it. They may also protect from exogenous retroviral infections: the virus-like transcripts can activate pattern recognition receptors, and the proteins can interfere with active retroviruses. A gag protein from HERV-K(HML2) is shown to mix with HIV Gag, impairing HIV capsid formation as a result. | 1 | Applied and Interdisciplinary Chemistry |
Triphosgene (bis(trichloromethyl) carbonate (BTC) is a chemical compound with the formula OC(OCCl). It is used as a solid substitute for phosgene, which is a gas and diphosgene, which is a liquid. Triphosgene is stable up to 200 °C. Triphosgene is used in a variety of halogenation reactions. | 0 | Theoretical and Fundamental Chemistry |
* 1901, Ramsay Silver Medal
* 1912, William H. Nichols Medal, New York Section of the American Chemical Society
* 1999, Laboratory recognized as a National Historic Chemical Landmark by the American Chemical Society
* 2000, inducted into the Alpha Chi Sigma Hall of Fame | 1 | Applied and Interdisciplinary Chemistry |
In competitive inhibition the substrate and inhibitor cannot bind to the enzyme at the same time. This usually results from the inhibitor having an affinity for the active site of an enzyme where the substrate also binds; the substrate and inhibitor compete for access to the enzymes active site. This type of inhibition can be overcome by sufficiently high concentrations of substrate (V remains constant), i.e., by out-competing the inhibitor. However, the apparent K will increase as it takes a higher concentration of the substrate to reach the K point, or half the V'. Competitive inhibitors are often similar in structure to the real substrate (see for example the "methotrexate versus folate" figure in the "Drugs" section). | 1 | Applied and Interdisciplinary Chemistry |
Reticulated foam is a very porous, low density solid foam. Reticulated means like a net. Reticulated foams are extremely open foams i.e. there are few, if any, intact bubbles or cell windows. In contrast, the foam formed by soap bubbles is composed solely of intact (fully enclosed) bubbles. In a reticulated foam only the lineal boundaries where the bubbles meet (Plateau borders) remain.
The solid component of a reticulated foam may be an organic polymer like polyurethane, a ceramic or a metal. These materials are used in a wide range of applications where the high porosity and large surface area are needed, including filters, catalyst supports, fuel tank inserts, and loudspeaker covers. | 0 | Theoretical and Fundamental Chemistry |
It was long considered that the best examples of neutral homoaromatics are bishomoaromatics such as barrelene and semibullvalene. First synthesized in 1966, semibullvalene has a structure that should lend itself well to homoaromaticity although there has been much debate whether semibullvalene derivatives can provide a true delocalized, ground state neutral homoaromatic compound or not. In an effort to further stabilize the delocalized transition structure by substituting semibullvalene with electron donating and accepting groups, it has been found that the activation barrier to this rearrangement can be lowered, but not eliminated. However, with the introduction of ring strain into the molecule, aimed at destabilizing the localized ground state structure's through the strategic addition of cyclic annulations, a delocalized homoaromatic ground-state structure can indeed be achieved.
Of the neutral homoaromatics, the compounds best believed to exhibit neutral homoaromaticity are boron containing compounds of 1,2-diboretane and its derivatives. Substituted diboretanes are shown to have a much greater stabilization in the delocalized state over the localized one, giving strong indications of homoaromaticity. When electron-donating groups are attached to the two boron atoms, the compound favors a classical model with localized bonds. Homoaromatic character is best seen when electron-withdrawing groups are bonded to the boron atoms, causing the compound to adopt a nonclassical, delocalized structure. | 0 | Theoretical and Fundamental Chemistry |
Radiant personal heaters are devices that convert energy into infrared radiation that are designed to increase a user's perceived temperature. They typically are either gas-powered or electric. In domestic and commercial applications, gas-powered radiant heaters can produce a higher heat flux than electric heaters which are limited by the amount of current that can be drawn through a circuit breaker. | 0 | Theoretical and Fundamental Chemistry |
In organic chemistry, Zaytsevs rule (or Zaitsevs rule, Saytzeffs rule, Saytzevs rule) is an empirical rule for predicting the favored alkene product(s) in elimination reactions. While at the University of Kazan, Russian chemist Alexander Zaytsev studied a variety of different elimination reactions and observed a general trend in the resulting alkenes. Based on this trend, Zaytsev proposed that the alkene formed in greatest amount is that which corresponded to removal of the hydrogen from the alpha-carbon having the fewest hydrogen substituents. For example, when 2-iodobutane is treated with alcoholic potassium hydroxide (KOH), but-2-ene is the major product and but-1-ene is the minor product.
More generally, Zaytsevs rule predicts that in an elimination reaction the most substituted product will be the most stable, and therefore the most favored. The rule makes no generalizations about the stereochemistry of the newly formed alkene, but only the regiochemistry of the elimination reaction. While effective at predicting the favored product for many elimination reactions, Zaytsevs rule is subject to many exceptions.
Many of them include exceptions under Hofmann product (analogous to Zaytsev product). These include compounds having quaternary nitrogen and leaving groups like NR, SOH, etc. In these eliminations the Hofmann product is preferred. In case the leaving group is halogens, except fluorine; others give the Zaytsev product. | 0 | Theoretical and Fundamental Chemistry |
Archaeal transcription shares eukaryotic and bacterial ties. With eukaryotes, it shares similarities with its initiation factors that help transcription identify appropriate sequences such as TATA box homologs as well as factors that maintain transcription elongation. However, additional transcription factors similar to those found in bacteria are needed for the whole process to occur.
In terms of transcription termination, the archaeal genome is unique in that it is sensitive to both intrinsic termination and factor-dependent termination. Bioinformatic analysis has shown that approximately half of the genes and operons in Archaea arrange themselves into signals or contain signals for intrinsic termination. Archaeal RNA polymerase is responsive to intrinsic signals both in vivo and in vitro such as the poly-U-rich regions. However, unlike bacterial intrinsic termination, no specific RNA structure or hairpin is needed. The surrounding environment and other genome factors can still influence the termination.
Factor-dependent termination in archaea is also distinct from factor-dependent termination in bacteria. The terminational factor aCASP1 (also known as FttA) recognizes poly-U-rich regions, probably cooperating with the "intrinsic" mode to achieve more efficient termination. | 1 | Applied and Interdisciplinary Chemistry |
The trivial name carbene is the preferred IUPAC name. The systematic names methylidene and dihydridocarbon, valid IUPAC names, are constructed according to the substitutive and additive nomenclatures, respectively.
Methylidene is viewed as methane with two hydrogen atoms removed. By default, this name pays no regard to the radicality of the methylene. Although in a context where the radicality is considered, it can also name the non-radical excited state, whereas the radical ground state with two unpaired electrons is named methanediyl.
Methylene is also used as the trivial name for the substituent groups methanediyl (), and methylidene ().
Methylene has an electron affinity of 0.65 eV. | 0 | Theoretical and Fundamental Chemistry |
In complex variable the H equation is
then for , a unique solution is given by
where the imaginary part of the function can vanish if is real i.e., . Then we have
The above solution is unique and bounded in the interval for conservative cases. In non-conservative cases, if the equation admits the roots , then there is a further solution given by | 0 | Theoretical and Fundamental Chemistry |
Both the oral and intravenous preparations of flucloxacillin are inexpensive and are available as the sodium salt flucloxacillin sodium, in capsules (250 or 500 mg), oral suspensions (125 mg/5 ml or 250 mg/5 ml), and injections (powder for reconstitution, 250, 500, 1000 and 2000 mg per vial).
Flucloxacillin is not commonly used in the United States or Canada as of 2011. In several other countries however, it is supplied under a variety of trade names including Floxapen, Flopen, Flubex, Flupen, Phylopen, and Staphylex. | 0 | Theoretical and Fundamental Chemistry |
Due to the relative age of the technology, it may be beneficial to discuss the operation of the multipath ultrasonic meter to illustrate the effects of flow profile distortion and swirl. There are various types of flow measurements utilizing high frequency sound. The custody transfer measurement devices available today utilize the time of travel concept. The difference in time of flight with the flow is compared to the time of flight against the flow. This difference is used to infer average flow velocity on the sound path. Fig.(5) showing the Ultrasonic Meter sound path no flow which illustrates this concept.
The resulting flow equation for the mean velocity experienced by the sound path is given by,
----(5)<br />
The case of no flow gives the actual path of the sound when there is zero flow (by equating eq.(5) to zero). In case of theoretical flow profile, say a uniform velocity flow profile where the no-slip condition on the pipe walls is not applied, Fig.(6) shows Ultrasonic Meter sound path - uniform velocity profile which illustrates the resultant sound path.
A theoretical derivation of the Mean velocity equation for this sound path becomes much more complicated. In case of a perfect fully developed real velocity profile of Ultrasonic meter which is shown in Fig.(7) indicating a possible sound path as a result of an installation in a real flow.
Here a mathematical derivation for this Ultrasonic meter is also becomes very complicated. Developing a robust flow algorithm to calculate the mean flow velocity for the sound path can be quite complicated. Now add to this; sound path reflection from the pipe wall, multipaths to add degrees of freedom, swirl and departure from axisymmetric fully developed flow profile and the problem of integrating the actual velocity flow profile to yield volume flow rate can be an accomplishment. Hence the real performance of ultrasonic meters downstream of perturbations, and the need for calibrations is required. | 1 | Applied and Interdisciplinary Chemistry |
The terms ‘sulfidic material’ and ‘sulfuric material’ were primarily coined by Prof Delvin Fanning (University of Maryland), Prof Martin Rabenhorst (University of Maryland), and Prof Rob Fitzpatrick (University of Adelaide) – and have been incorporated into the Australian Soil Classification (ASC) and World Reference Base (WRB) as diagnostic features of soil. For example, under the ASC, a Sulfuric Extratidal Hydrosol would refer to a soil that is saturated for 2-3 months of the year (i.e., a Hydrosol), located in an extratidal setting, and which contains sulfuric material. Therefore, acid sulfate soils may be described more technically as soils that contain sulfidic and/or sulfuric material.
Sulfuric material refers to soil material that has a pH of less than 4 owing to the oxidation of sulfidic material.
Sulfidic material refers to “soil materials containing detectable inorganic sulfides (≥0.01% sulfidic sulfur) that can exist as horizons or layers at least 30 mm thick or as surficial features”, and is further divided into 3 classes: hyposulfidic, hypersulfidic, and monosulfidic.
Conceptually, hyposulfidic and hypersulfidic materials are used to distinguish between sulfidic material that, respectively, would not and would experience a drop in pH to below 4 if exposed to prevailing oxidising conditions. By definition, hyposulfidic material does not convert to sulfuric material upon oxidation.
In contrast to both hyposulfidic and hypersulfidic materials, monosulfidic material contains high concentrations of detectable monosulfides (≥ 0.01% acid volatile sulfide) (e.g., greigite and mackinawite). Note that monosulfidic material has not replaced Monosulfidic Black Ooze (MBO), which is now considered a type of monosulfidic material.
The terms ‘sulfidisation’ and ‘sulfuricisation’ were coined to refer to the formation of sulfidic and sulfuric material, respectively. Although the terms have not been formally adopted in the ASC, their use is encouraged in Australia. However, the terms should not be used synonymously with other terms that also refer to the formation or transformation of sulfides (e.g., pyritization). Similarly, sulfidic material should not be used interchangeably with similar terms such as pyritic/sulfidic sediment, rock and regolith, which may be found in publications on Acid Rock systems. The broad term sulfidic geomedia could be used to refer to both sulfidic material and pyritic/sulfidic sediment, rock and regolith; but it has no formal definition in Australia and should not be used in lieu of sulfidic material. | 0 | Theoretical and Fundamental Chemistry |
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