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Below is the sequence of events that are followed in phage display screening to identify polypeptides that bind with high affinity to desired target protein or DNA sequence:
# Target proteins or DNA sequences are immobilized to the wells of a microtiter plate.
# Many genetic sequences are expressed in a bacteriophage library in the form of fusions with the bacteriophage coat protein, so that they are displayed on the surface of the viral particle. The protein displayed corresponds to the genetic sequence within the phage.
# This phage-display library is added to the dish and after allowing the phage time to bind, the dish is washed.
# Phage-displaying proteins that interact with the target molecules remain attached to the dish, while all others are washed away.
# Attached phage may be eluted and used to create more phage by infection of suitable bacterial hosts. The new phage constitutes an enriched mixture, containing considerably less irrelevant phage (i.e. non-binding) than were present in the initial mixture.
# Steps 3 to 5 are optionally repeated one or more times, further enriching the phage library in binding proteins.
# Following further bacterial-based amplification, the DNA within the interacting phage is sequenced to identify the interacting proteins or protein fragments. | 1 | Applied and Interdisciplinary Chemistry |
Niobium–tin is an intermetallic compound of niobium (Nb) and tin (Sn), used industrially as a type-II superconductor. This intermetallic compound has a simple structure: A3B. It is more expensive than niobium–titanium (NbTi), but remains superconducting up to a magnetic flux density of , compared to a limit of roughly 15 T for NbTi.
NbSn was discovered to be a superconductor in 1954. The material's ability to support high currents and magnetic fields was discovered in 1961 and started the era of large-scale applications of superconductivity.
The critical temperature is . Application temperatures are commonly around , the boiling point of liquid helium at atmospheric pressure.
In April 2008 a record non-copper current density was claimed of 2,643 A mm at 12 T and 4.2 K. | 1 | Applied and Interdisciplinary Chemistry |
For a gas parcel, the density will only remain fixed as assumed in the previous derivation if the pressure, , is constant with height, which is not true in an atmosphere confined by gravity. Instead, the parcel will expand adiabatically as the pressure declines. Therefore a more general formulation used in meteorology is:
: , where is potential temperature, is the local acceleration of gravity, and is geometric height.
Since , where is a constant reference pressure, for a perfect gas this expression is equivalent to:
where in the last form , the adiabatic index. Using the ideal gas law, we can eliminate the temperature to express in terms of pressure and density:
This version is in fact more general than the first, as it applies when the chemical composition of the gas varies with height, and also for imperfect gases with variable adiabatic index, in which case , i.e. the derivative
is taken at constant entropy, .
If a gas parcel is pushed up and , the air parcel will move up and down around the height where the density of the parcel matches the density of the surrounding air. If the air parcel is pushed up and , the air parcel will not move any further. If the air parcel is pushed up and , (i.e. the Brunt–Väisälä frequency is imaginary), then the air parcel will rise and rise unless becomes positive or zero again further up in the atmosphere. In practice this leads to convection, and hence the Schwarzschild criterion for stability against convection (or the Ledoux criterion if there is compositional stratification) is equivalent to the statement that should be positive.
The Brunt–Väisälä frequency commonly appears in the thermodynamic equations for the atmosphere and in the structure of stars. | 1 | Applied and Interdisciplinary Chemistry |
A cumulative or overall constant, given the symbol β, is the constant for the formation of a complex from reagents. For example, the cumulative constant for the formation of ML is given by
:M + 2 L ML; [ML] = β[M][L]
The stepwise constant, K, for the formation of the same complex from ML and L is given by
:ML + L ML; [ML] = K[ML][L] = Kβ[M][L]
It follows that
:β = Kβ
A cumulative constant can always be expressed as the product of stepwise constants. There is no agreed notation for stepwise constants, though a symbol such as K is sometimes found in the literature. It is best always to define each stability constant by reference to an equilibrium expression. | 0 | Theoretical and Fundamental Chemistry |
Biota are organisms that, along with organic matter, help comprise the biological system of the soil. The vast majority of biological activity takes place near the soil surface, usually in the A horizon of a soil profile. Biota rely on inputs of organic matter in order to sustain themselves and increase population sizes. In return, they contribute nutrients to the soil, typically after it has been cycled in the soil trophic food web.
With the many different interactions that take place, biota can largely impact their environment physically, chemically, and biologically (Pavao-Zuckerman, 2008). A prominent factor that helps to provide some degree of stability with these interactions is biodiversity, a key component of all ecological communities. Biodiversity allows for a consistent flow of energy through trophic levels and strongly influences the structure of ecological communities in the soil. | 0 | Theoretical and Fundamental Chemistry |
In regards to electrochemical reactions, two main types of reactions can be visualized using the Frost diagram. Comproportionation is when two equivalents of an element, differing in oxidation number, combine to form a product with an intermediate oxidation number. Disproportionation is the opposite reaction, in which two equivalents of an element, identical in oxidation number, react to form two products of differing oxidation numbers.
Disproportionation: 2 M → M + M.
Comproportionation: M + M → 2 M.
2 n = m + p in both examples.
Using a Frost diagram, one can predict whether one oxidation number would undergo disproportionation or two oxidation numbers would undergo comproportionation. Looking at two slopes among a set of three oxidation numbers on the diagram, assuming the two standard potentials (slopes) are not equal, the middle oxidation will either be in a “hill” or “valley” form. A hill is formed when the left slope is steeper than the right, and a valley is formed when the right slope is steeper than the left. An oxidation number that is on “top of the hill” tends to favor disproportionation into the adjacent oxidation states. The adjacent oxidation states, however, will favor comproportionation if the middle oxidation state is in the “bottom of a valley”.
By Jensen's inequality, drawing the line between the oxidation state to the left and the one to the right and seeing if the species lies above or below this line is a quick way to determine concavity/convexity (concavity would indicate comproportionation, for example) | 0 | Theoretical and Fundamental Chemistry |
A vortex sheet is a term used in fluid mechanics for a surface across which there is a discontinuity in fluid velocity, such as in slippage of one layer of fluid over another. While the tangential components of the flow velocity are discontinuous across the vortex sheet, the normal component of the flow velocity is continuous. The discontinuity in the tangential velocity means the flow has infinite vorticity on a vortex sheet.
At high Reynolds numbers, vortex sheets tend to be unstable. In particular, they may exhibit Kelvin–Helmholtz instability.
The formulation of the vortex sheet equation of motion is given in terms of a complex coordinate . The sheet is described parametrically by where is the arclength between coordinate and a reference point, and is time. Let denote the strength of the sheet, that is, the jump in the tangential discontinuity. Then the velocity field induced by the sheet is
The integral in the above equation is a Cauchy principal value integral. We now define as the integrated sheet strength or circulation between a point with arc length and the reference material point in the sheet.
As a consequence of Kelvin's circulation theorem, in the absence of external forces on the sheet, the circulation between any two material points in the sheet remains conserved, so
This nonlinear integro-differential equation is called the Birkoff-Rott equation. It describes the evolution of the vortex sheet given initial conditions. Greater details on vortex sheets can be found in the textbook by Saffman (1977). | 1 | Applied and Interdisciplinary Chemistry |
This reactivity is exploited in the regiospecific preparation of many di- and tri-substituted aromatic compounds. The approach exploits the meta-directing effect of the sulfonic acid group. 2-Chlorotoluene for example can be prepared by chlorination of p-toluenesulfonic acid, followed by hydrolysis. The method is also useful for the preparation of 2,6-dinitroaniline and 2-bromophenol via phenol-2,4-disulfonic acid. | 0 | Theoretical and Fundamental Chemistry |
In organic chemistry and biochemistry, a side chain is a chemical group that is attached to a core part of the molecule called the "main chain" or backbone. The side chain is a hydrocarbon branching element of a molecule that is attached to a larger hydrocarbon backbone. It is one factor in determining a molecule's properties and reactivity. A side chain is also known as a pendant chain, but a pendant group (side group) has a different definition. | 0 | Theoretical and Fundamental Chemistry |
Removal of a proton from an aliphatic –OH group is difficult to achieve in aqueous solution because the energy required for this process is rather large. Thus, ionization of aliphatic –OH groups occurs in aqueous solution only in special circumstances. One such circumstance is found with compounds containing the HN–C–C–OH substructure. For example, compounds containing the 2-aminoethanol substructure can form metal–chelate complexes with the deprotonated form, HN–C–C–O. The chelate effect supplies the extra energy needed to break the O–H bond.
An important example occurs with the molecule tris. This molecule should be used with caution as a buffering agent as it will form chelate complexes with ions such as Fe and Cu. | 0 | Theoretical and Fundamental Chemistry |
The Société de Chimie Industrielle (American Section) is now an independent organization. It was granted tax status as a 501(c)(3), a registered nonprofit organization as of 1952. The American Section is directed by a board of officers including a president. , the president of the Société de Chimie Industrielle (American section) is [James M. Weatherall]. | 1 | Applied and Interdisciplinary Chemistry |
It is not always possible to eliminate ion suppression by sample preparation and/or chromatographic resolution. In such cases it may be possible to compensate for the effects of ion suppression on accuracy and precision (although not for analytical sensitivity) by adopting complex calibration strategies. | 0 | Theoretical and Fundamental Chemistry |
EmBiology Data sources include:
* 7.2 million PubMed abstracts
* 430,000 from Clinicaltrials.gov
* 7.2 million Full-text articles from 936 Elsevier journals and 939 non-Elsevier journals | 1 | Applied and Interdisciplinary Chemistry |
Lanthanum acetate is used in specialty glass manufacturing and in water treatment.
Also, it is used to produce porous lanthanum oxyfluoride (LaOF) films.
It is also used as a component in the production of ceramic products and as a catalyst in the pharmaceutical industry. | 0 | Theoretical and Fundamental Chemistry |
The effective overall energy unit for the available body energy is referred to as the daily glycogen generation capacity, and is used to compare the mitochondrial output of affected or chronically glycogen-depleted individuals to healthy individuals. This value is slow to change in a given individual, as it takes between 18 and 24 months to complete a full cycle.
The glycogen generation capacity is entirely dependent on, and determined by, the operating levels of the mitochondria in all of the cells of the human body; however, the relation between the energy generated by the mitochondria and the glycogen capacity is very loose and is mediated by many biochemical pathways. The energy output of full healthy mitochondrial function can be predicted exactly by a complicated theoretical argument, but this argument is not straightforward, as most energy is consumed by the brain and is not easily measurable. | 1 | Applied and Interdisciplinary Chemistry |
The fitting method used in Rietveld refinement is the non-linear least squares approach. A detailed derivation of non-linear least squares fitting will not be given here. Further detail can be found in Chapter 6 of Pecharsky and Zavalij's text 12 . There are a few things to note however. First, non-linear least squares fitting has an iterative nature for which convergence may be difficult to achieve if the initial approximation is too far from correct, or when the minimized function is poorly defined. The latter occurs when correlated parameters are being refined at the same time, which may result in divergence and instability of the minimization. This iterative nature also means that convergence to a solution does not occur immediately for the method is not exact. Each iteration depends on the results of the last which dictate the new set of parameters used for refinement. Thus, multiple refinement iterations are required to eventually converge to a possible solution. | 0 | Theoretical and Fundamental Chemistry |
Accidentally consuming small quantities of clean seawater is not harmful, especially if the seawater is taken along with a larger quantity of fresh water. However, drinking seawater to maintain hydration is counterproductive; more water must be excreted to eliminate the salt (via urine) than the amount of water obtained from the seawater itself. In normal circumstances, it would be considered ill-advised to consume large amounts of unfiltered seawater.
The renal system actively regulates the levels of sodium and chloride in the blood within a very narrow range around 9 g/L (0.9% by mass).
In most open waters concentrations vary somewhat around typical values of about 3.5%, far higher than the body can tolerate and most beyond what the kidney can process. A point frequently overlooked in claims that the kidney can excrete NaCl in Baltic concentrations of 2% (in arguments to the contrary) is that the gut cannot absorb water at such concentrations, so that there is no benefit in drinking such water. The salinity of Baltic surface water, however, is never 2%. It is 0.9% or less, and thus never higher than that of bodily fluids. Drinking seawater temporarily increases bloods NaCl concentration. This signals the kidney to excrete sodium, but seawaters sodium concentration is above the kidneys maximum concentrating ability. Eventually the bloods sodium concentration rises to toxic levels, removing water from cells and interfering with nerve conduction, ultimately producing fatal seizure and cardiac arrhythmia.
Survival manuals consistently advise against drinking seawater. A summary of 163 life raft voyages estimated the risk of death at 39% for those who drank seawater, compared to 3% for those who did not. The effect of seawater intake on rats confirmed the negative effects of drinking seawater when dehydrated.
The temptation to drink seawater was greatest for sailors who had expended their supply of fresh water and were unable to capture enough rainwater for drinking. This frustration was described famously by a line from Samuel Taylor Coleridges The Rime of the Ancient Mariner':
Although humans cannot survive on seawater, some people claim that up to two cups a day, mixed with fresh water in a 2:3 ratio, produces no ill effect. The French physician Alain Bombard survived an ocean crossing in a small Zodiak rubber boat using mainly raw fish meat, which contains about 40% water (like most living tissues), as well as small amounts of seawater and other provisions harvested from the ocean. His findings were challenged, but an alternative explanation was not given. In his 1948 book The Kon-Tiki Expedition, Thor Heyerdahl reported drinking seawater mixed with fresh in a 2:3 ratio during the 1947 expedition. A few years later, another adventurer, William Willis, claimed to have drunk two cups of seawater and one cup of fresh per day for 70 days without ill effect when he lost part of his water supply.
During the 18th century, Richard Russell advocated the medical use of this practice in the UK, and René Quinton expanded the advocation of this practice to other countries, notably France, in the 20th century. Currently, it is widely practiced in Nicaragua and other countries, supposedly taking advantage of the latest medical discoveries.
Most oceangoing vessels desalinate potable water from seawater using processes such as vacuum distillation or multi-stage flash distillation in an evaporator, or, more recently, reverse osmosis. These energy-intensive processes were not usually available during the Age of Sail. Larger sailing warships with large crews, such as Nelson's , were fitted with distilling apparatus in their galleys.
Animals such as fish, whales, sea turtles, and seabirds, such as penguins and albatrosses, have adapted to living in a high-saline habitat. For example, sea turtles and saltwater crocodiles remove excess salt from their bodies through their tear ducts. | 0 | Theoretical and Fundamental Chemistry |
Normative mineralogy is an estimate of the mineralogy of the rock. It usually differs from the visually observable mineralogy, at least as much as the types of mineral species, especially amongst the ferromagnesian minerals and feldspars, where it is possible to have many solid solution series of minerals, or minerals with similar Fe and Mg ratios substituting, especially with water (e.g.; amphibole and biotite replacing pyroxene).
However, in aphanites, or rocks with phenocrysts clearly out of equilibrium with the groundmass, a normative mineral calculation is often the best to understand the evolution of the rock and its relationship to other igneous rocks in the region. | 0 | Theoretical and Fundamental Chemistry |
MsO may be prepared by the dehydration of methanesulfonic acid with phosphorus pentoxide.
:PO + 6 CHSOH → 3 (CHSO)O + 2 HPO
MsO can be purified by distillation under vacuum (distillation of a solid) or by recrystallization from Methyl tert-butyl ether/toluene. | 0 | Theoretical and Fundamental Chemistry |
This enzyme is a part of a family of enzymes called glycoside hydrolase family 31 (GH31). This is due to the digestive mechanism of the enzyme. GH31 enzymes undergo what is known as the Koshland double displacement mechanism in which a glycosylation and deglycosylation step occurs, resulting in the retention of the overall configuration of the anomeric center. | 1 | Applied and Interdisciplinary Chemistry |
Mammalian-wide interspersed repeats (MIRs) are transposable elements in the genomes of some organisms and belong to the group of Short interspersed nuclear elements (SINEs). | 1 | Applied and Interdisciplinary Chemistry |
* In 2021 Kubista's organization, TATAA was on Sweden Technology Fast 50 list
* In 2019, Global Health & Pharma recognized and awarded TATAA as the "Best Nucleic Acid Analysis Service Provider – Europe."
* In 2013 TATAA Biocenter was honored with the Frost & Sullivan Award for Customer Value Leadership for their outstanding services in analyzing genetic material
* In 2012, Pioneer of the year in western Sweden
* In 1996, won Innovation Cup in western Sweden for the LightUp probes | 1 | Applied and Interdisciplinary Chemistry |
Adsorbable organic halides (AOX) is a measure of the organic halogen load at a sampling site such as soil from a land fill, water, or sewage waste. The procedure measures chlorine, bromine, and iodine as equivalent halogens, but does not measure fluorine levels in the sample. | 1 | Applied and Interdisciplinary Chemistry |
Dexamethasone (DEX) is a glucocorticoid that is used as an anti-inflammatory and immunosuppressive agent. PLGA nanoparticles loaded with DEX via oil-in-water emulsion/solvent evaporation method can be embedded in alginate hydrogel matrices. To quantify the amount of DEX that was successfully seeding into the nanoparticle, UV spectrophotometry can be used. It has been shown that the amount of DEX that can be successfully loaded into the nanoparticles was ≈13 wt% and the typical particle size ranged from 400 to 600 nm.
In vitro tests have revealed that the impedance of the nanoparticle-loaded hydrogel-coated electrodes have similar impedance to the non-coated electrode (bare gold). This shows that the nanoparticle-loaded hydrogel coating does not significantly hinder the electrical transport. The in vivo tests have shown that the impedance amplitude of the DEX-loaded electrodes was maintained at the same level it was at initially. However, non-coated electrodes had an impedance about 3 times greater than its original impedance 2 weeks earlier. This addition of anti-inflammatory drugs via nanoparticles indicates that this form of surface modification does not have a negative effect on the electrodes performance. | 0 | Theoretical and Fundamental Chemistry |
The Buchner-Curtius-Schlotterbeck reaction yields ketones from aldehydes and aliphatic diazo compounds:
The reaction type is nucleophilic addition. | 0 | Theoretical and Fundamental Chemistry |
Fritz Johann Hansgirg (18911949) was an Austrian electrochemist and metallurgist who in 1928 invented a carbothermic magnesium reduction process. In 1934, he left Austria for the Empire of Japan where he worked with industrialist Shitagau Noguchi to set up a magnesium plant, and then helped build a pilot plant to produce heavy water using a combined electrolysis catalytic exchange process he had invented. He moved to the United States in 1940, where he worked with industrialist Henry J. Kaiser to design a magnesium plant in California. In 1941, Hansgirg was arrested by the FBI on a presidential warrant and interned for "the duration of the war". After the war, the Soviet Union captured Hansgirgs plants in northern Korea, using the plants processes and equipment for their atomic bomb project. | 0 | Theoretical and Fundamental Chemistry |
Early African miners used copper oxides and carbonates rather than sulfides, because they were able to reduce oxides and carbonates to copper metal, but not sulfides. Sulfides were more complex to reduce to metal and required multiple stages. Complex deep-mining methods and special tools were not needed, because oxides were structurally weakened by decomposition processes and contained the most desirable ores, and although the techniques used seemed to be simple, Africans were very successful in extracting large quantities of high-grade ore.
The copper mines themselves were most frequently open stopes or open stopes with shafts. Shafts were rare in African copper mining. There are several ethnographic accounts of African copper mining techniques, and they all seem to be on the same technological level. Any variation depended upon different geological circumstances and capabilities of the miners.
There are more variations of copper smelting than there are of mining, and most of the observations and photos that were taken are in major copper producing areas. There is a lack of evidence of smelting in West Africa; however casting continued to be present and is well documented. The most common ore in Africa is malachite and it was used mainly with hardwood charcoal the smelting process. | 1 | Applied and Interdisciplinary Chemistry |
The Chesapeake Bay, the largest estuary in the U.S., has suffered from repeated large algal blooms for decades due to chemical runoff from multiple sources, including 9 large rivers and 141 smaller streams and creeks in parts of six states. In addition, the water is quite shallow and only 1% of the waste entering it gets flushed into the ocean.
By weight, 60% of the phosphates entering the bay in 2003 were from sewage treatment plants, while 60% of its nitrates came from fertilizer runoff, farm animal waste, and the atmosphere. About 300 million pounds (140 Gg) of nitrates are added to the bay each year. The population increase in the bay watershed, from 3.7 million people in 1940 to 18 million in 2015 is also a major factor, as economic growth leads to the increased use of fertilizers and rising emissions of industrial waste.
As of 2015, the six states and the local governments in the Chesapeake watershed have upgraded their sewage treatment plants to control nutrient discharges. The U.S. Environmental Protection Agency (EPA) estimates that sewage treatment plant improvements in the Chesapeake region between 1985 and 2015 have prevented the discharge of 900 million pounds (410 Gg) of nutrients, with nitrogen discharges reduced by 57% and phosphorus by 75%. Agricultural and urban runoff pollution continue to be major sources of nutrients in the bay, and efforts to manage those problems are continuing throughout the watershed. | 0 | Theoretical and Fundamental Chemistry |
In 1982, Martha C. Rose Chemical Inc. began processing and disposing of materials contaminated with PCBs in Holden, Missouri, a small rural community about east of Kansas City. From 1982 until 1986, nearly 750 companies, including General Motors Corp., Commonwealth Edison, Illinois Power Co. and West Texas Utilities, sent millions of pounds of PCB contaminated materials to Holden for disposal. Instead, according to prosecutors, the company began storing the contaminated materials while falsifying its reports to the EPA to show they had been removed. After investigators learned of the deception, Rose Chemical was closed and filed for bankruptcy. The site had become the nation's largest waste site for the chemical PCB. In the four years the company was operational, the EPA inspected it four times and assessed $206,000 in fines but managed to collect only $50,000.
After the plant closed the state environmental agency found PCB contamination in streams near the plant and in the city's sewage treatment sludge. A 100,000 square-foot warehouse and unknown amounts of contaminated soil and water around the site had to be cleaned up. Most of the surface debris, including close to 13 million pounds of contaminated equipment, carcasses and tanks of contaminated oil, had to be removed. Walter C. Carolan, owner of Rose Chemical, and five others pleaded guilty in 1989 to committing fraud or falsifying documents. Carolan and two other executives served sentences of less than 18 months; the others received fines and were placed on probation. Cleanup costs at the site are estimated at $35 million. | 1 | Applied and Interdisciplinary Chemistry |
A cloud chamber, also known as a Wilson cloud chamber, is a particle detector used for visualizing the passage of ionizing radiation.
A cloud chamber consists of a sealed environment containing a supersaturated vapor of water or alcohol. An energetic charged particle (for example, an alpha or beta particle) interacts with the gaseous mixture by knocking electrons off gas molecules via electrostatic forces during collisions, resulting in a trail of ionized gas particles. The resulting ions act as condensation centers around which a mist-like trail of small droplets form if the gas mixture is at the point of condensation. These droplets are visible as a "cloud" track that persists for several seconds while the droplets fall through the vapor. These tracks have characteristic shapes. For example, an alpha particle track is thick and straight, while a beta particle track is wispy and shows more evidence of deflections by collisions.
Cloud chambers were invented in the early 1900s by the Scottish physicist Charles Thomson Rees Wilson. They played a prominent role in experimental particle physics from the 1920s to the 1950s, until the advent of the bubble chamber. In particular, the discoveries of the positron in 1932 (see Fig. 1) and the muon in 1936, both by Carl Anderson (awarded a Nobel Prize in Physics in 1936), used cloud chambers. Discovery of the kaon by George Rochester and Clifford Charles Butler in 1947, also was made using a cloud chamber as the detector. In each of these cases, cosmic rays were the source of ionizing radiation. Yet they were also used with artificial sources of particles, for example in radiography applications as part of the Manhattan Project. | 0 | Theoretical and Fundamental Chemistry |
Multicomponent reactions have been known for over 150 years. The first documented multicomponent reaction was the Strecker synthesis of α-amino cyanides in 1850 from which α-amino acids could be derived. A multitude of MCRs exist today, of which the isocyanide based MCRs are the most documented. Other MCRs include free-radical mediated MCRs, MCRs based on organoboron compounds and metal-catalyzed MCRs.
Isocyanide based MCRs are most frequently exploited because the isocyanide is an extraordinary functional group. It is believed to exhibit resonance between its tetravalent and divalent carbon forms. This induces the isocyanide group to undergo both electrophilic and nucleophilic reactions at the CII atom, which then converts to the CIV form in an exothermic reaction. The occurrence of isocyanides in natural products has also made it a useful functional group. The two most important isocyanide-based multicomponent reactions are the Passerini 3-component reaction to produce α-acyloxy carboxamides and the Ugi 4-component reaction, which yields the α-amino carboxamides.
Examples of three component reactions:
* Alkyne trimerisation
* Biginelli reaction
* Bucherer–Bergs reaction
* Gewald reaction
* Grieco three-component coupling
* Hantzsch pyridine synthesis
* Kabachnik–Fields reaction
* Mannich reaction
* Passerini reaction
* Pauson–Khand reaction
* Petasis reaction
* Strecker amino acid synthesis
* Ugi reaction
* Asinger reaction
* A3 coupling reaction
The exact nature of this type of reaction is often difficult to assess, in collision theory a simultaneous interaction of 3 or more different molecules is less likely resulting in a low reaction rate. These reactions are more likely to involve a series of bimolecular reactions.
New MCRs are found by building a chemical library from combinatorial chemistry or by combining existing MCRs. For example, a 7-component MCR results from combining the Ugi reaction with the Asinger reaction. MCRs are an important tool in new drug discovery. MCRs can often be extended into combinatorial, solid phase or flow syntheses for developing new lead structures of active agents. | 0 | Theoretical and Fundamental Chemistry |
The α-aminoadipate pathway is a biochemical pathway for the synthesis of the amino acid -lysine. In the eukaryotes, this pathway is unique to several species of yeast, higher fungi (containing chitin in their cell walls), and the euglenids. It has also been reported from bacteria of the genus Thermus and also in Pyrococcus horikoshii, potentially suggesting a wider distribution than previously thought. This uniqueness of the pathway makes it a potentially interesting target for antimycotics. | 1 | Applied and Interdisciplinary Chemistry |
Glutaminolysis (glutamine + -lysis) is a series of biochemical reactions by which the amino acid glutamine is lysed to glutamate, aspartate, CO, pyruvate, lactate, alanine and citrate. | 1 | Applied and Interdisciplinary Chemistry |
In 1958, Frederick C. Frank and John S. Kasper, in their original work investigating many complex alloy structures, showed that non-icosahedral environments form an open-end network which they called the major skeleton, and is now identified as the declination locus. They came up with the methodology to pack asymmetric icosahedra into crystals using other polyhedra with larger coordination numbers. These coordination polyhedra were constructed to maintain topological close packing (TCP). | 1 | Applied and Interdisciplinary Chemistry |
20α,22R-Dihydroxycholesterol, or (3β)-cholest-5-ene-3,20,22-triol is an endogenous, metabolic intermediate in the biosynthesis of the steroid hormones from cholesterol. Cholesterol ((3β)-cholest-5-en-3-ol) is hydroxylated by cholesterol side-chain cleavage enzyme (P450scc) to form 22R-hydroxycholesterol, which is subsequently hydroxylated again by P450scc to form 20α,22R-dihydroxycholesterol, and finally the bond between carbons 20 and 22 is cleaved by P450scc to form pregnenolone ((3β)-3-hydroxypregn-5-en-20-one), the precursor to the steroid hormones. | 1 | Applied and Interdisciplinary Chemistry |
Pd-NHC complexes used in Sonogashira cross-coupling effect temperature stability in the complex. As in other Pd-NHC mediated cross-coupling reactions, the use of Pd-NHC complexes also allow higher turnover numbers than their NHC-free counterparts. NHC-palladacycles permit copper-free Sonogashira reactions to be carried out. | 0 | Theoretical and Fundamental Chemistry |
The basic idea of quantum typicality is that the vast majority of all pure states featuring a common expectation value of some generic observable at a given time will yield very similar expectation values of the same observable at any later time.
This is meant to apply to Schrödinger type dynamics in high dimensional Hilbert spaces. As a consequence individual dynamics of expectation values are then typically well described by the ensemble average.
Quantum ergodic theorem originated by John von Neumann is a strong result arising from the mere mathematical structure of quantum mechanics. The QET is a precise formulation of termed normal typicality, i.e. the statement that, for typical large systems, every initial wave function from an energy shell is ‘normal’: it evolves in such a way that for most t, is macroscopically equivalent to the micro-canonical density matrix. | 0 | Theoretical and Fundamental Chemistry |
Ramboll Studio Dreiseitl Was one of the leading landscape architecture practices of Germany specialising in the integration of art, urban hydrology, environmental engineering, and landscape architecture within an urban context.
The practise was founded in 1980 by the German landscape architect Herbert Dreiseitl with a goal to promote sustainable projects with a high aesthetic and social value. Today it has offices in Germany, Singapore and Beijing.
In May 2013, Atelier Dreiseitl was renamed Ramboll Studio Dreiseitl GmbH and became a partner within the international engineering consultancy, the Ramboll Group A/S, based in Copenhagen.
On April 3, 2023, Ramboll Studio Dreiseitl joined the international architecture, landscape architecture and urbanism studio Henning Larsen, and is now part of the Henning Larsen team, | 1 | Applied and Interdisciplinary Chemistry |
Gilbert N. Lewis was the first to discover that heavy water inhibits (retards) seed growth (1933). His experiments with tobacco seeds showed that cultivation of cells on heavy water dramatically accelerates the aging process and leads to lethal results. | 0 | Theoretical and Fundamental Chemistry |
Polyethers are generally polymers containing ether linkages in their main chain. The term polyol generally refers to polyether polyols with one or more functional end-groups such as a hydroxyl group. The term "oxide" or other terms are used for high molar mass polymer when end-groups no longer affect polymer properties.
Crown ethers are cyclic polyethers. Some toxins produced by dinoflagellates such as brevetoxin and ciguatoxin are extremely large and are known as cyclic or ladder polyethers.
The phenyl ether polymers are a class of aromatic polyethers containing aromatic cycles in their main chain: polyphenyl ether (PPE) and poly(p-phenylene oxide) (PPO). | 0 | Theoretical and Fundamental Chemistry |
Fatty acids, stored as triglycerides in an organism, are a concentrated source of energy because they contain little oxygen and are anhydrous. The energy yield from a gram of fatty acids is approximately 9 kcal (37 kJ), much higher than the 4 kcal (17 kJ) for carbohydrates. Since the hydrocarbon portion of fatty acids is hydrophobic, these molecules can be stored in a relatively anhydrous (water-free) environment. Carbohydrates, on the other hand, are more highly hydrated. For example, 1 g of glycogen binds approximately 2 g of water, which translates to 1.33 kcal/g (4 kcal/3 g). This means that fatty acids can hold more than six times the amount of energy per unit of stored mass. Put another way, if the human body relied on carbohydrates to store energy, then a person would need to carry 31 kg (67.5 lb) of hydrated glycogen to have the energy equivalent to 4.6 kg (10 lb) of fat.
Hibernating animals provide a good example for utilization of fat reserves as fuel. For example, bears hibernate for about 7 months, and during this entire period, the energy is derived from degradation of fat stores. Migrating birds similarly build up large fat reserves before embarking on their intercontinental journeys.
The fat stores of young adult humans average between about 10–20 kg, but vary greatly depending on gender and individual disposition. By contrast, the human body stores only about 400 g of glycogen, of which 300 g is locked inside the skeletal muscles and is unavailable to the body as a whole. The 100 g or so of glycogen stored in the liver is depleted within one day of starvation. Thereafter the glucose that is released into the blood by the liver for general use by the body tissues has to be synthesized from the glucogenic amino acids and a few other gluconeogenic substrates, which do not include fatty acids. Nonetheless, lipolysis releases glycerol which can enter the pathway of gluconeogenesis. | 1 | Applied and Interdisciplinary Chemistry |
Vaiśeṣika Sūtra (Sanskrit: वैशेषिक सूत्र), also called Kanada sutra, is an ancient Sanskrit text at the foundation of the Vaisheshika school of Hindu philosophy. The sutra was authored by the Hindu sage Kanada, also known as Kashyapa. According to some scholars, he flourished before the advent of Buddhism because the Vaiśeṣika Sūtra makes no mention of Buddhism or Buddhist doctrines; however, the details of Kanadas life are uncertain, and the Vaiśeṣika Sūtra' was likely compiled sometime between 6th and 2nd century BCE, and finalized in the currently existing version before the start of the common era.
A number of scholars have commented on it since the beginning of common era; the earliest commentary known is the Padartha Dharma Sangraha of Prashastapada. Another important secondary work on Vaiśeṣika Sūtra is Maticandras Dasha padartha sastra' which exists both in Sanskrit and its Chinese translation in 648 CE by Yuanzhuang.
The Vaiśeṣika Sūtra is written in aphoristic sutras style, and presents its theories on the creation and existence of the universe using naturalistic atomism, applying logic and realism, and is one of the earliest known systematic realist ontology in human history. The text discusses motions of different kind and laws that govern it, the meaning of dharma, a theory of epistemology, the basis of Atman (self, soul), and the nature of yoga and moksha. The explicit mention of motion as the cause of all phenomena in the world and several propositions about it make it one of the earliest texts on physics. | 1 | Applied and Interdisciplinary Chemistry |
Low molecular weight acyl chlorides are often lachrymators, and they react violently with water, alcohols, and amines. | 0 | Theoretical and Fundamental Chemistry |
Polymer-Protein nanoparticles not only contain the traditional properties of nanoparticles, but also have their own unique properties based on the properties of specific proteins. Because they are proteinaceous, they have high biocompatibility, biodegradability and biofunctionality. Protein-polymer bioconjugates which is the building block of Polymer-Protein hybrids exhibit a unique array of properties such as: light-switching effects, acoustic signal capture, thermal energy transfer, and magnetic signal response. | 1 | Applied and Interdisciplinary Chemistry |
The Occupational Safety and Health Administration (OSHA) is the regulatory body covering worker safety. OSHA puts forth permissible exposure limit (PEL) 20 ppb for MDI and detailed technical guidance on exposure assessment.
The National Institutes of Health (NIOSH) is the agency responsible for providing the research and recommendations regarding workplace safety, while OSHA is more of an enforcement body. NIOSH is responsible for producing the science that can result in recommended exposure limits (REL), which can be lower than the PEL. OSHA is tasked with enforcement and defending the enforceable limits (PELs). In 1992, when OSHA reduced the PEL for TDI to the NIOSH REL, the PEL reduction was challenged in court, and the reduction was reversed.
The Environmental Protection Agency (EPA) is also involved in the regulation of isocyanates with regard to the environment and also non-worker persons that might be exposed.
The American Conference of Governmental Industrial Hygienists (ACGIH) is a non-government organization that publishes guidance known as threshold limit values (TLV) for . The TLV is not an OSHA-enforceable value, unless the PEL is the same. | 0 | Theoretical and Fundamental Chemistry |
Particle technology thus deals with:
*the behavior of solids in bulk, including soil mechanics, bulk material handling, silos, conveying, powder metallurgy, nanotechnology;
*size reduction including crushing and grinding;
*increasing size by flocculation, granulation, powder compaction, tableting, crystallization
*particle separation, such as sieving, tabling, flotation, magnetic separation, and/or electrostatic precipitation, fluidization, Centrifugal separation, Liquid filtration;
*analytical procedures such as particle size analysis. | 1 | Applied and Interdisciplinary Chemistry |
While Gas Chromatography, HPLC, and Mass Spectrometry are all excellent techniques for distinguishing mixtures of compounds (and sometimes even enantiomers), the time resolution of these measurements is less precise than that of the techniques described above. Regardless, these techniques have still seen use, such as in the investigation of the Heck reaction where the heterogeneous nature of the reaction precluded utilization of the techniques described above. and SOMO-activation by organocatalysts Despite their shortcomings, these techniques may serve as excellent calibration methods. | 0 | Theoretical and Fundamental Chemistry |
Testing and scientific certainty were desired at the end of the 1940s. To that end products meant to be used by humans were tested with model animals to speed trials. Eddy & McGregor 1949 and Wiesmann & Lotmar 1949 used mice, Wasicky et al. 1949 canaries and guinea pigs, Kasman et al. 1953 also guinea pigs, Starnes & Granett 1953 rabbits, and many used cattle. | 1 | Applied and Interdisciplinary Chemistry |
For large base-sizes, some of the cyclobutanes can be fused anti to each other, giving a non-convex polygon base. These are geometric isomers of the prismanes. Two isomers of [12]prismane that have been studied computationally are named helvetane and israelane, based on the star-like shapes of the rings that form their bases. This was explored computationally after originally being proposed as an April fools joke. Their names refer to the shapes found on the flags of Switzerland and Israel, respectively. | 0 | Theoretical and Fundamental Chemistry |
Consider a semi-ideal heat engine, in which heat transfer takes time, according to Fourier's law of heat conduction: , but other operations happen instantly.
Its maximal efficiency is the standard Carnot result, but it requires heat transfer to be reversible (quasistatic), thus taking infinite time. At maximum power output, its efficiency is the Chambadal–Novikov efficiency:
Due to occasional confusion about the origins of the above equation, it is sometimes named the Chambadal–Novikov–Curzon–Ahlborn efficiency. | 0 | Theoretical and Fundamental Chemistry |
As illustrated to the right, tholins are thought to form in nature through a chain of chemical reactions known as pyrolysis and radiolysis. This begins with the dissociation and ionization of molecular nitrogen () and methane () by energetic particles and solar radiation. This is followed by the formation of ethylene, ethane, acetylene, hydrogen cyanide, and other small simple molecules and small positive ions. Further reactions form benzene and other organic molecules, and their polymerization leads to the formation of an aerosol of heavier molecules, which then condense and precipitate on the planetary surface below.
Tholins formed at low pressure tend to contain nitrogen atoms in the interior of their molecules, while tholins formed at high pressure are more likely to have nitrogen atoms located in terminal positions.
Tholins may be a major constituent of the interstellar medium. On Titan, their chemistry is initiated at high altitudes and participates in the formation of solid organic particles.
These atmospherically-derived substances are distinct from ice tholin II, which are formed instead by irradiation (radiolysis) of clathrates of water and organic compounds such as methane () or ethane (). The radiation-induced synthesis on ice are non-dependant on temperature.
Models show that even when far from UV radiation of a star, cosmic ray doses may be fully sufficient to convert carbon-containing ice grains entirely to complex organics in less than the lifetime of the typical interstellar cloud. | 0 | Theoretical and Fundamental Chemistry |
In aquatic sediments, several reactions can transform the chemicals released by the creosote preservatives into more dangerous chemicals. Most creosote preservative compounds have hazards associated with them before they are transformed. Cresol (m-, p-, and o-), phenol, guaiacol, and xylenol (1,3,4- and 1,3,5-) all are acute aquatic hazards prior to going through chemical reactions with the sediments. Alkylation reactions allows for the compounds to transition into more toxic compounds with the addition of R-groups to the major compounds found in creosote preservatives. Compounds formed through alkylation include: 3,4-dimethylphenol, 2,3-dimethylphenol, and 2,5-dimethylphenol, which are all listed as acute environmental hazards. Biodegradation controls the rate at which the sediment holds the chemicals, and the number of reactions that are able to take place. The biodegradation process can take place under many different conditions, and vary depending on the compounds that are released. Oxidation-reduction reactions allow for the compounds to be broken down into new forms of more toxic molecules. Studies have shown oxidation-reduction reactions of creosote preservative compounds included compounds that are listed as environmental hazards, such as p-benzoquinone in the oxidation of phenol. Not only are the initial compounds in creosote hazardous to the environment, but the byproducts of the chemical reactions are environmental hazardous as well. | 0 | Theoretical and Fundamental Chemistry |
Durrant was educated at Gresham's School in Norfolk, the University of Cambridge and Imperial College London, where he was awarded a PhD in 1991 for research on photosystem II using spectroscopy supervised by George Porter and Jim Barber. | 0 | Theoretical and Fundamental Chemistry |
In molecular physics, crystal field theory (CFT) describes the breaking of degeneracies of electron orbital states, usually d or f orbitals, due to a static electric field produced by a surrounding charge distribution (anion neighbors). This theory has been used to describe various spectroscopies of transition metal coordination complexes, in particular optical spectra (colors). CFT successfully accounts for some magnetic properties, colors, hydration enthalpies, and spinel structures of transition metal complexes, but it does not attempt to describe bonding. CFT was developed by physicists Hans Bethe and John Hasbrouck van Vleck in the 1930s. CFT was subsequently combined with molecular orbital theory to form the more realistic and complex ligand field theory (LFT), which delivers insight into the process of chemical bonding in transition metal complexes. CFT can be complicated further by breaking assumptions made of relative metal and ligand orbital energies, requiring the use of inverted ligand field theory (ILFT) to better describe bonding. | 0 | Theoretical and Fundamental Chemistry |
A licensed CIT is certified to work in a chemistry profession. Upon completing a certain amount of work experience under the supervision of a Licensed Professional Chemist (P.Chem.) as determined by a licensing board, a CIT is then eligible to gain experience by supervision from a P.Chem.
While being a certified CIT may help in obtaining a chemistry related job, it is not typically required to do chemistry work. All work performed by an CIT must still be checked and certified by a P.Chem. | 1 | Applied and Interdisciplinary Chemistry |
Redox conditions are measured according to the redox potential (E) in volts, which represents the tendency for electrons to transfer from an electron donor to an electron acceptor. E can be calculated using half reactions and the Nernst equation. An E of zero represents the redox couple of the standard hydrogen electrode H/H a positive E indicates an oxidizing environment (electrons will be accepted), and a negative E indicates a reducing environment (electrons will be donated). In a redox gradient, the most energetically favorable chemical reaction occurs at the “top” of the redox ladder and the least energetically favorable reaction occurs at the “bottom” of the ladder.
E can be measured by collecting samples in the field and performing analyses in the lab, or by inserting an electrode into the environment to collect in situ measurements. Typical environments to measure redox potential are in bodies of water, soils, and sediments, all of which can exhibit high levels of heterogeneity. Collecting a high number of samples can produce high spatial resolution, but at the cost of low temporal resolution since samples only reflect a singular a snapshot in time. In situ monitoring can provide high temporal resolution by collecting continuous real-time measurements, but low spatial resolution since the electrode is in a fixed location.
Redox properties can also be tracked with high spatial and temporal resolution through the use of induced-polarization imaging, however, further research is needed to fully understand contributions of redox species to polarization. | 0 | Theoretical and Fundamental Chemistry |
Aerobic fermentation evolved independently in at least three yeast lineages (Saccharomyces, Dekkera, Schizosaccharomyces). It has also been observed in plant pollen, trypanosomatids, mutated E. coli, and tumor cells. Crabtree-positive yeasts will respire when grown with very low concentrations of glucose or when grown on most other carbohydrate sources. The Crabtree effect is a regulatory system whereby respiration is repressed by fermentation, except in low sugar conditions. When Saccharomyces cerevisiae is grown below the sugar threshold and undergoes a respiration metabolism, the fermentation pathway is still fully expressed, while the respiration pathway is only expressed relative to the sugar availability. This contrasts with the Pasteur effect, which is the inhibition of fermentation in the presence of oxygen and observed in most organisms.
The evolution of aerobic fermentation likely involved multiple successive molecular steps, which included the expansion of hexose transporter genes, copy number variation (CNV) and differential expression in metabolic genes, and regulatory reprogramming. Research is still needed to fully understand the genomic basis of this complex phenomenon. Many Crabtree-positive yeast species are used for their fermentation ability in industrial processes in the production of wine, beer, sake, bread, and bioethanol. Through domestication, these yeast species have evolved, often through artificial selection, to better fit their environment. Strains evolved through mechanisms that include interspecific hybridization, horizontal gene transfer (HGT), gene duplication, pseudogenization, and gene loss. | 1 | Applied and Interdisciplinary Chemistry |
* C. Michael Hogan, Leda C. Patmore and Harry Seidman (1973) Statistical Prediction of Dynamic Thermal Equilibrium Temperatures using Standard Meteorological Data Bases, Second Edition (EPA-660/2-73-003 2006) United States Environmental Protection Agency Office of Research and Development, Washington, D.C. [http://library.wur.nl/WebQuery/catalog/lang/1851848]
* Cesare Barbieri (2007) Fundamentals of Astronomy. First Edition (QB43.3.B37 2006) CRC Press ,
* F. Mandl (1988) Statistical Physics, Second Edition, John Wiley & Sons
* Hans R. Griem (2005) Principles of Plasma Spectroscopy (Cambridge Monographs on Plasma Physics), Cambridge University Press, New York | 0 | Theoretical and Fundamental Chemistry |
Most natural lipase inhibitors differ only in the structure of the side chains and the nature of the linked amino acids, but have the same β-lactone ring in (S)-configuration as a primary structure.
Besides the role of the β-lactone ring in structure-activity relationship, the nature of the functional groups (e.g. ester or ether and the chain length at the β-site) also matter. However a trans-position of the side-chains on the β-lactone ring is crucial for its activity. | 1 | Applied and Interdisciplinary Chemistry |
The BBOC furnace is a cylindrical steel vessel with a protective internal lining of refractory bricks. It is mounted on a tilting frame that allows it to be held at different angles at different stages of its operating cycle (see Figure 2). A hood is fixed over the top of the furnace, providing a seal that prevents lead and other fumes from escaping during the furnace’s operation (see Figure 1).
The key feature of the BBOC is the shrouded lance that passes through the refractory bricks at the bottom of the furnace. This lance allows oxygen to be injected directly into the molten metal contained in the furnace, away from the refractory lining. Doing so allows the region of high reaction rates to be removed from the vicinity of the lining, thus reducing its wear.
By injecting the oxygen directly into the bath, rather than blowing it on top (as in the case of the reverberatory cupellation furnace or top-blown rotary converters), the oxygen transfer efficiency is not impeded by the presence of the slag layer. It results in an oxygen utilization efficiency approaching 100%.
The lack of interference in the oxygen transfer by the slag layer has a couple of key benefits. The first is that the increased certainty in the estimation of oxygen utilization efficiency means that it is easier to calculate the endpoint of the process, making process control much easier. The second is that a thicker slag layer can be tolerated (because the oxygen does not have to pass through it), and this means that the losses of silver to the slag are reduced (because it is the silver at the interface between the metal and slag that becomes entrained during the removal of the slag and the thicker the slag layer, the smaller the silver content of the removed slag). BRM reported a decrease in the silver content of the BBOC slag compared to the reverberatory furnace slag of 50%.
BRM found that the reaction rate of the BBOC was 10–20 times that of its reverberatory cupellation furnace.
Refractory wear in the BBOC is largely confined to the slag line, at the top of the metal, where attack by litharge (lead oxide) is greatest. This is combated by using fused-grain, direct-bonded magnesite-chrome bricks to line the inside of the furnace shell. | 1 | Applied and Interdisciplinary Chemistry |
10-acetyl-3,7-dihydroxyphenoxazine (also known as Amplex Red), structurally related to resazurin, reacts with HO in a 1:1 stoichiometry to produce the same by-product resorufin (used in many assays combining for example horseradish peroxidase (HRP), or NADH, NADPH using enzymes).
7-ethoxyresorufin, a compound used as the substrate in the measurement of cytochrome P450 (CYP1A1) induction using the ethoxyresorufin-O-deethylase (EROD) assay system in cell culture and environmental samples, produced in response to exposure to aryl hydrocarbons. The compound is catalysed by the enzyme to produce the same fluorescent product, resorufin.
1,3-dichloro-7-hydroxy-9,9-dimethylacridin-2(9H)-one (DDAO dye), a fluorescent dye used for oligonucleotide labeling. | 0 | Theoretical and Fundamental Chemistry |
The cut-and-paste transposition mechanism of class II TEs does not involve an RNA intermediate. The transpositions are catalyzed by several transposase enzymes. Some transposases non-specifically bind to any target site in DNA, whereas others bind to specific target sequences. The transposase makes a staggered cut at the target site producing sticky ends, cuts out the DNA transposon and ligates it into the target site. A DNA polymerase fills in the resulting gaps from the sticky ends and DNA ligase closes the sugar-phosphate backbone. This results in target site duplication and the insertion sites of DNA transposons may be identified by short direct repeats (a staggered cut in the target DNA filled by DNA polymerase) followed by inverted repeats (which are important for the TE excision by transposase).
Cut-and-paste TEs may be duplicated if their transposition takes place during S phase of the cell cycle, when a donor site has already been replicated but a target site has not yet been replicated. Such duplications at the target site can result in gene duplication, which plays an important role in genomic evolution.
Not all DNA transposons transpose through the cut-and-paste mechanism. In some cases, a replicative transposition is observed in which a transposon replicates itself to a new target site (e.g. helitron).
Class II TEs comprise less than 2% of the human genome, making the rest Class I. | 1 | Applied and Interdisciplinary Chemistry |
Fuchter earned a master's degree (MSci) in chemistry at the University of Bristol, where he was awarded the Richard Dixon prize. It was during his undergraduate degree that he first became interested in organic synthesis. As a graduate student he moved to Imperial College London, where he worked with Anthony Barrett on the synthesis and applications of porphyrazines, including as therapeutic agents. During his doctoral studies Barrett and Fuchter collaborated with Brian M. Hoffman at Northwestern University. | 1 | Applied and Interdisciplinary Chemistry |
Nitrogen can be fixed by lightning converting nitrogen gas () and oxygen gas () in the atmosphere into (nitrogen oxides). The molecule is highly stable and nonreactive due to the triple bond between the nitrogen atoms. Lightning produces enough energy and heat to break this bond allowing nitrogen atoms to react with oxygen, forming . These compounds cannot be used by plants, but as this molecule cools, it reacts with oxygen to form , which in turn reacts with water to produce (nitrous acid) or (nitric acid). When these acids seep into the soil, they make (nitrate), which is of use to plants. | 1 | Applied and Interdisciplinary Chemistry |
Orphan MTases are common in bacteria and archea CcrM is found in almost every group of Alphaproteobacteria, excepting in Rickettsiales and Magnetococcales, and homologs can be found in Campylobacterota and Gammaproteobacteria. Alphaproteobacteria are organisms with different life stages from free living to substrate associated, some of them are intracellular pathogens of plants, animal and even human, in those groups the CcrMs must have an important role in cell cycle progression.
CcrM miss regulation have shown to produce severe miss control of cell cycle regulation and differentiation in various Alphaproteobacteria; C. crescentus , the plant symbiont Sinorhizobium meliloti and in the human pathogen Brucella abortus. Also CcrM gene has proven to be essential for the viability of various Alphaproteobacteria. | 1 | Applied and Interdisciplinary Chemistry |
Pyruvate kinase catalyzes the last step within glycolysis, the dephosphorylation of phosphoenolpyruvate to pyruvate, and is responsible for net ATP production within the glycolytic sequence. In contrast to mitochondrial respiration, energy regeneration by pyruvate kinase is independent from oxygen supply and allows survival of the organs under hypoxic conditions often found in solid tumors.
The involvement of this enzyme in a variety of pathways, protein–protein interactions, and nuclear transport suggests its potential to perform multiple nonglycolytic functions with diverse implications, although multidimensional role of this protein is as yet not fully explored. However, a functional role in angiogenesis the so-called process of blood vessel formation by interaction and regulation of Jmjd8 has been shown. | 1 | Applied and Interdisciplinary Chemistry |
As is obvious from their origins, the above cancer chemotherapies are essentially poisons. Patients receiving these agents experienced severe side-effects that limited the doses which could be administered, and hence limited the beneficial effects. Clinical investigators realized that the ability to manage these toxicities was crucial to the success of cancer chemotherapy.
Several examples are noteworthy. Many chemotherapeutic agents cause profound suppression of the bone marrow. This is reversible, but takes time to recover. Support with platelet and red-cell transfusions as well as broad-spectrum antibiotics in case of infection during this period is crucial to allow the patient to recover.
Several practical factors are also worth mentioning. Most of these agents caused very severe nausea (termed chemotherapy-induced nausea and vomiting (CINV) in the literature) which, while not directly causing patient deaths, was unbearable at higher doses. The development of new drugs to prevent nausea (the prototype of which was ondansetron) was of great practical use, as was the design of indwelling intravenous catheters (e.g. Hickman lines and PICC lines) which allowed safe administration of chemotherapy as well as supportive therapy. | 1 | Applied and Interdisciplinary Chemistry |
Light production in Photurius pennsylvanica (Photuris pennsylvanica) larvae occurs in the roughly 2,000 photocytes located in the heavily innervated light organ of the insect which is much simpler than that of the adult organism. The transparent photocytes of the larvae are clearly distinguishable from the opaque dorsal layer cells that cover them. Nervous and intracellular mechanisms contribute to light production in the photocytes. Nervous and intracellular mechanisms contribute to light production in the photocytes.It has been shown that fireflies can modify the amount of oxygen that travels through their trachea system to the light organ which plays a role in oxygen availability for light production. They do this by modifying the amount of fluid present within the trachea system. Because oxygen diffuses more slowly through water than in a gaseous form, this allows fireflies to effectively change the amount of oxygen reaching the photocytes. Spiracles can be opened and closed to control the amount of air that is able to pass through the tracheal system, but this control mechanism is only used as a response to a stressor. | 1 | Applied and Interdisciplinary Chemistry |
* The French writer René Daumal intoxicated himself by inhalation of carbon tetrachloride which he used to kill the beetles he collected, to "encounter other worlds" by voluntarily plunging himself into intoxications close to comatose states.
* Carbon tetrachloride is listed (along with salicylic acid, toluene, sodium tetraborate, silica gel, methanol, potassium carbonate, ethyl acetate and "BHA") as an ingredient in Peter Parkers (Spider-Man) custom web fluid formula in the book The Wakanda Files: A Technological Exploration of the Avengers and Beyond'.
* Australian YouTuber Tom of Explosions&Fire and Extractions&Ire made a video on extracting carbon tetrachloride from an old fire extinguisher in 2019, and later experimenting with it by mixing it with sodium, and the chemical gained a fan base called "Tet Gang" on social media (especially on Reddit). The channel owner later used carbon tetrachloride-themed designs in the channel's merch.
* In the Ramones song "Carbona Not Glue" released in 1977, the narrator says that huffing the vapours of Carbona, a carbon tetrachloride-based stain remover, was better than huffing glue. They later removed the song from the album as Carbona was a corporate trademark. | 1 | Applied and Interdisciplinary Chemistry |
The theory of bimodal AFM operation encompasses several aspects. Among them, the approximations to express the Euler-Bernoulli equation of a continuous cantilever beam in terms of the equations of the excited modes, the type of interaction forces acting on the tip, the theory of demodulation methods or the introduction of finite-size effects.
In a nutshell, the tip displacement in AFM is approximated by a point-mass model,
where , , , , , and are, respectively, the driving frequency, the free resonant frequency, the quality factor, the stiffness, the driving force of the i-th mode, and the tip–sample interaction force. In bimodal AFM, the vertical motion of the tip (deflection) has two components, one for each mode,
with , , , as the static, the first, and the second mode deflections; , and are, respectively, the amplitude, frequency and phase shift of mode i.
The theory that transforms bimodal AFM observables into material properties is based on applying the virial and energy dissipation theorems to the equations of motion of the excited modes. The following equations were derived
where is a time where the oscillation of both modes are periodic; the quality factor of mode i. Bimodal AFM operation might be involve any pair of eigenmodes. However, experiments are commonly performed by exciting the first two eigenmodes.
The theory of bimodal AFM provides analytical expressions to link material properties with microscope observables. For example, for a paraboloid probe (radius ) and a tip-sample force given by the linear viscoelastic Kelvin-Voigt model, the effective elastic modulus of the sample, viscous coefficient of compressibility , loss tangent or retardation time are expressed by
For an elastic material, the second term of equation to calculate disappears because which gives . The elastic modulus is obtained from the equation above. Other analytical expressions were proposed for the determination of the Hamaker constant and the magnetic parameters of a ferromagnetic sample. | 0 | Theoretical and Fundamental Chemistry |
Sulfur diimides are chemical compounds of the formula S(NR). Structurally, they are the diimine of sulfur dioxide. The parent member, S(NH), is of only theoretical interest. Other derivatives where R is an organic group are stable and useful reagents. | 0 | Theoretical and Fundamental Chemistry |
There are four principal protein targets with which drugs can interact:
* Enzymes (e.g. neostigmine and acetyl cholinesterase)
** Inhibitors
** Inducers
** Activators
* Membrane carriers [<nowiki/>Reuptake vs Efflux] (e.g. tricyclic antidepressants and catecholamine uptake-1)
** Enhancer (RE)
** Inhibitor (RI)
** Releaser (RA)
* Ion channels (e.g. nimodipine and voltage-gated Ca channels)
** Blocker
** Opener
* Receptor (e.g. Listed in table below)
** Agonists can be full, partial or inverse.
** Antagonists can be competitive, non-competitive, or uncompetive.
** Allosteric modulator can have 3 effects within a receptor. One is its capability or incapability to activate a receptor (2 possibilities). The other two are agonist affinity and efficacy. They may be increased, decreased or unaffected (3 and 3 possibilities).
NMBD = neuromuscular blocking drugs; NMDA = N-methyl-d-aspartate; EGF = epidermal growth factor. | 1 | Applied and Interdisciplinary Chemistry |
The chemical character of azo violet may be attributed to its azo group (-N=N-), six-membered rings, and hydroxyl side groups. Due to steric repulsions, azo violet is most stable in the trans-configuration, but isomerization of azo dyes by irradiation is not uncommon. The para-position tautomerization of azo violet provides mechanical insight into the behavior of the compound in an acidic environment, and thus its use as a basic pH indicator.
The predicted H-NMR of pure azo violet shows the hydroxyl protons as the most deshielded and acidic protons. The participation of these hydroxyl groups electron-donation to the conjugated π system likewise influences azo violets λ and pK value. | 0 | Theoretical and Fundamental Chemistry |
Soil bacteria and archaea account for approximately 5% of the natural methane sink. Early research is going into how the activity of these bacteria may be able to be enhanced, either through the use of soil amendments, or introduction of selected or engineered methane-oxidizing bacteria. | 1 | Applied and Interdisciplinary Chemistry |
Vacuum plasma spraying (VPS) is a technology for etching and surface modification to create porous layers with high reproducibility and for cleaning and surface engineering of plastics, rubbers and natural fibers as well as for replacing CFCs for cleaning metal components. This surface engineering can improve properties such as frictional behavior, heat resistance, surface electrical conductivity, lubricity, cohesive strength of films, or dielectric constant, or it can make materials hydrophilic or hydrophobic.
The process typically operates at 39–120 °C to avoid thermal damage. It can induce non-thermally activated surface reactions, causing surface changes which cannot occur with molecular chemistries at atmospheric pressure. Plasma processing is done in a controlled environment inside a sealed chamber at a medium vacuum, around 13–65 Pa.
The gas or mixture of gases is energized by an electrical field from DC to microwave frequencies, typically 1–500 W at 50 V. The treated components are usually electrically isolated. The volatile plasma by-products are evacuated from the chamber by the vacuum pump, and if necessary can be neutralized in an exhaust scrubber.
In contrast to molecular chemistry, plasmas employ:
* Molecular, atomic, metastable and free radical species for chemical effects.
* Positive ions and electrons for kinetic effects.
Plasma also generates electromagnetic radiation in the form of vacuum UV photons to penetrate bulk polymers to a depth of about 10 μm. This can cause chain scissions and cross-linking.
Plasmas affect materials at an atomic level. Techniques like X-ray photoelectron spectroscopy and scanning electron microscopy are used for surface analysis to identify the processes required and to judge their effects.
As a simple indication of surface energy, and hence adhesion or wettability, often a water droplet contact angle test is used.
The lower the contact angle, the higher the surface energy and more hydrophilic the material is. | 1 | Applied and Interdisciplinary Chemistry |
In a low concentration (approximately 10%), nitric acid is often used to artificially age pine and maple. The color produced is a grey-gold very much like very old wax- or oil-finished wood (wood finishing). | 0 | Theoretical and Fundamental Chemistry |
Aminomethanol or methanolamine is the amino alcohol with the chemical formula of HNCHOH. With an amino group and an alcohol group on the same carbon atom, the compound is also an hemiaminal.
In aqueous solution, methanolamine exists in equilibrium with formaldehyde and ammonia. It is an intermediate en route to hexamethylenetetramine. The reaction can be conducted in gas phase and in solution. | 0 | Theoretical and Fundamental Chemistry |
Exposure of a positive resist to radiation changes the chemical structure such that it becomes a liquid or more soluble. These changes in chemical structure are often rooted in the cleavage of specific linkers in the polymer. Once irradiated, the "decomposed" polymers can be washed away using a developer solvent leaving behind the polymer that was not exposed to light. This type of technology allows the production of very fine stencils for applications such as microelectronics. In order to have these types of qualities, positive resists utilize polymers with labile linkers in their back bone that can be cleaved upon irradiation, or use a photo-generated acid to hydrolyze bonds in the polymer. A polymer that decomposes upon irradiation to a liquid or more soluble product is referred to as a positive tone resist. Common functional groups that can be hydrolyzed by a photo-generated acid catalyst include polycarbonates and polyesters. | 0 | Theoretical and Fundamental Chemistry |
Halomethane compounds are derivatives of methane () with one or more of the hydrogen atoms replaced with halogen atoms (F, Cl, Br, or I). Halomethanes are both naturally occurring, especially in marine environments, and human-made, most notably as refrigerants, solvents, propellants, and fumigants. Many, including the chlorofluorocarbons, have attracted wide attention because they become active when exposed to ultraviolet light found at high altitudes and destroy the Earth's protective ozone layer. | 1 | Applied and Interdisciplinary Chemistry |
An ion channel can be characterized by its opening characteristics, ion selectivity, and control of flux (gating). Many synthetic ion channels show unique properties in one or more of these aspects. | 0 | Theoretical and Fundamental Chemistry |
This form of corrosion is usually caused by a combination of corrosion and cyclic stress. Measuring and controlling this is difficult because of the many factors at play including the nature or form of the stress cycle. The stress cycles cause localized work hardening. So avoiding stress concentrators such as holes etc would be good corrosion engineering design. | 1 | Applied and Interdisciplinary Chemistry |
Collectin-10, also known as collectin liver 1, is a collectin protein that in humans is encoded by the COLEC10 gene. Its structure is similar to mannan-binding lectin (MBL).
Collectin liver 1 (CL-L1) show very similar carbohydrate selectivity as MBL. Two other discovered collectins include collectin placenta 1 (CL-P1) and collectin kidney 1 (CL-K1). CL-L1's location found to be on chromosome 8 q23-24.1. Research concluded CL-L1 to be a serum protein. | 1 | Applied and Interdisciplinary Chemistry |
The Serine-Histidine-Aspartate motif is one of the most thoroughly characterised catalytic motifs in biochemistry. The triad is exemplified by chymotrypsin, a model serine protease from the PA superfamily which uses its triad to hydrolyse protein backbones. The aspartate is hydrogen bonded to the histidine, increasing the pK of its imidazole nitrogen from 7 to around 12. This allows the histidine to act as a powerful general base and to activate the serine nucleophile. It also has an oxyanion hole consisting of several backbone amides which stabilises charge build-up on intermediates. The histidine base aids the first leaving group by donating a proton, and also activates the hydrolytic water substrate by abstracting a proton as the remaining OH attacks the acyl-enzyme intermediate.
The same triad has also convergently evolved in α/β hydrolases such as some lipases and esterases, however orientation of the triad members is reversed. Additionally, brain acetyl hydrolase (which has the same fold as a small G-protein) has also been found to have this triad. The equivalent Ser-His-Glu triad is used in acetylcholinesterase. | 1 | Applied and Interdisciplinary Chemistry |
Some food writers advise against using seasoned pans and Dutch ovens to cook foods containing tomatoes, vinegar, or other acidic ingredients because these foods would eventually remove the protective layer created during the seasoning process. Tests conducted by America's Test Kitchen found that, while cooking a highly acidic tomato sauce for over 30 minutes produced a metallic taste, cooking acidic food in a well-seasoned pan for a short time is unlikely to have negative consequences.
Cast iron pots are best suited to cook food high in oil or fat, such as chicken, bacon, or sausage, or used for deep frying. Cleaning (except prior to seasoning) is often carried out without the use of detergent. Some cookbook authors recommend only wiping seasoned cookware clean after each use or using other cleaning methods such as a salt scrub or boiling water. The protective layer itself is not very susceptible to soaps, and many users do briefly use detergents and soaps. However, cast iron is very prone to rust, and the protective layer may have pinholes, so soaking for long periods is contraindicated as the layer may start to flake off.
Unlike commercial non-stick coatings such as Teflon, with which metal cooking utensils are not used because they damage the surface, seasoned surfaces tend to be self-reforming, so they allow the use of such utensils. These are of course much more effective in scraping off food than the softer utensils used with non-stick pans. | 0 | Theoretical and Fundamental Chemistry |
Schizophrenia is a psychological disorder in which a patient experiences symptoms including hallucinations, delusions, amotivation, social withdrawal, cognitive defects, and poor working memory. Heredity and gene inheritance is a highly important risk factor, especially for identical twins. Schizophrenia is anatomically characterized by a deterioration and loss of gray matter in the temporal and frontal regions of the cerebral cortex, though the exact mechanism is unknown. What is known is that the main two neurotransmitter systems implicated in schizophrenia are the dopamine and glutamate pathways.
Dopamine became a candidate for research when it was clinically noticed that antipsychotic drugs which are dopamine D receptor antagonists were noted to be quite successful in treating schizophrenia as well. Increased levels of dopamine in people with schizophrenia tend to induce paranoid delusions, ideas of reference, and auditory hallucinations. The same dopaminergic pathway is also involved in psychosis.
Glutamate has become a candidate for treatment focus because glutamate blocks some NMDA receptors which, on their own, induce schizophrenic behavior. In animal models, NMDA antagonists increase glutamate release in the prefrontal cortex. It is postulated that this is a homeostatic response to NMDA receptor blockade, which in turn increases psychotic symptoms. A class of NMDA receptor antagonists have been denoted dissociative anesthetics because they produce a sense of depersonalization and dissociation of subjective experience from various forms of sensory input stimuli. As such, variants such as Ketamine (Angel Dust/Special K) and Phencyclidine (PCP) have become a commonly abused street-drug. These drugs are no longer used due to harmful behavioral and addictive effects. | 1 | Applied and Interdisciplinary Chemistry |
Viel is co-author of The Inner Life of the Cell, an 8.5-minute 3D computer graphics animation illustrating the molecular mechanisms that occur when a white blood cell in the blood vessels of the human body is activated by inflammation (Leukocyte extravasation). It shows how a white blood cell rolls along the inner surface of the capillary, flattens out, and squeezes through the cells of the capillary wall to the site of inflammation where it contributes to the immune reaction. | 1 | Applied and Interdisciplinary Chemistry |
Although covalent conjugation has been the dominant strategy for constructing polymer-protein hybrids, noncovalent chemistry can add another level of complexity and provides the opportunity to create higher-ordered structures. Specifically, self-assembly by non-covalent interactions is progressing rapidly. Supramolecular self-assembly can create nanoparticles, vesicles/micelles, protein cages, etc. Metal-binding interactions, host-guest, and boronic acid-based chemistries are widely studied as non-covalent conjugation methods to create polymer-protein hybrids. | 1 | Applied and Interdisciplinary Chemistry |
The advantage of NMR for end groups is that it allows for not only the identification of the end group units, but also allows for the quantification of the number-average length of the polymer. End-group analysis with NMR requires that the polymer be soluble in organic or aqueous solvents. Additionally, the signal on the end-group must be visible as a distinct spectral frequency, i.e. it must not overlap with other signals. As molecular weight increases, the width of the spectral peaks also increase. As a result of this, methods which rely on resolution of the end-group signal are mostly used for polymers of low molecular weight (roughly less than 20,000 g/mol number-average molecular weight). By using the information obtained from the integration of a H NMR spectrum, the degree of polymerization (X) can be calculated. With knowledge of the identity of the end groups/repeat unit and the number of protons contained on each, the X can then be calculated. For this example above, once the 1H NMR has been integrated and the values have been normalized to 1, the degree of polymerization is calculated by simply dividing the normalized value for the repeat unit by the number of protons continued in the repeat unit. For this case, X = n = 100/2, and therefore X = 50, or there are 50 repeat units in this monomer. | 0 | Theoretical and Fundamental Chemistry |
In April 2014, a team of scientists led by Anthony Atala reported that they had successfully transplanted laboratory-grown vaginas into four female teenaged girls with a rare medical condition called Mayer-Rokitansky-Küster-Hauser syndrome that causes the vagina to develop improperly, or sometimes not at all. Between 1 of 1,500 to 4,000 females are born with this condition.
The four patients began treatment between May 2005 and August 2008. In each case, the medical research team began by taking a small sample of genital tissue from the teenagers vulva. The sample was used as a seed to grow additional tissue in the lab which was then placed in a vaginal shaped, biodegradable mold. Vaginal-lining cells were placed on the inside of the tube, while muscle cells were attached to the outside. Five to six weeks later, the structure was implanted into the patients, where the tissue continued to grow and connected with the girls circulatory and other bodily systems. After about eight years, all four patients reported normal function and pleasure levels during sexual intercourse according to the Female Sexual Function Index questionnaire, a validated self-report tool. No adverse results or complications were reported.
In two of the four women, the vagina was attached to the uterus, making pregnancy possible. No pregnancies were reported, however, during the study period. Martin Birchall, who works on tissue engineering, but was not involved in the study, said it "addressed some of the most important questions facing translation of tissue engineering technologies." Commentary published by the National Health Service (NHS) called the study "an important proof of concept" and said it showed that tissue engineering had "a great deal of potential." However, the NHS also cautioned that the sample size was very small and further research was necessary to determine the general viability of the technique.
The laboratory-grown autologous transplant technique could also be used on women who want reconstructive surgery due to cancer or other disease once the technique is perfected. However, more studies will need to be conducted and the techniques further developed before commercial production can begin. | 1 | Applied and Interdisciplinary Chemistry |
A similar phenomenon arising from the same centrifugal action is sometimes observed in rotational flows which do not follow a curved wall, such as the rib vortices seen in the wakes of cylinders and generated behind moving structures. | 1 | Applied and Interdisciplinary Chemistry |
Carbon has three naturally occurring isotopes. About 99% of carbon on Earth is carbon-12 (C), about 1% is carbon-13 (C), and a trace amount is carbon-14 (C). The C and C isotopes are stable, while C decays radioactively to nitrogen-14 (N) with a half-life of 5730 years. C on Earth is produced nearly exclusively by the interaction of cosmic radiation with the upper atmosphere. A C atom is created when a thermal neutron displaces a proton in N. Minuscule amounts of C are produced by other radioactive processes; a large amount was produced in the atmosphere during nuclear testing before the Limited Test Ban Treaty. Natural C production and hence atmospheric concentration varies only slightly over time.
Plants take up C by fixing atmospheric carbon through photosynthesis. Animals then take C into their bodies when they consume plants (or consume other animals that consume plants). Thus, living plants and animals have nearly the same ratio of C to C as the atmospheric CO. Once organisms die they stop exchanging carbon with the atmosphere and thus no longer take up new C. This effect is the basis of radiocarbon dating, with the proviso that mass-dependent fractionation and the decrease in C due to radioactive decay and are accounted for.
Photosynthetically fixed carbon in terrestrial plants is depleted in C compared to atmospheric CO. This fractionation of carbon isotopes is caused by kinetic isotope effects and mass dependence of CO diffusivity. The overall effect is slight in C4 plants but much greater in C3 plants which form the bulk of terrestrial biomass worldwide. Depletion in CAM plants vary between the values observed for C3 and C4 plants. In addition, most fossil fuels originate from C3 biological material produced tens to hundreds of millions of years ago. C4 plants did not become common until about 6 to 8 million years ago, and although CAM photosynthesis is present in modern relatives of the Lepidodendrales of the Carboniferous lowland forests, even if these plants also had CAM photosynthesis they were not a major component of the total biomass.
Fossil fuels such as coal and oil are made primarily of plant material that was deposited millions of years ago. This period of time equates to thousands of half-lives of C, so essentially all of the C in fossil fuels has decayed. Fossil fuels also are depleted in C relative to the atmosphere, because they were originally formed from living organisms. Therefore, the carbon from fossil fuels that is returned to the atmosphere through combustion is depleted in both C and C compared to atmospheric carbon dioxide. | 0 | Theoretical and Fundamental Chemistry |
The single survivin gene can give rise to four different alternatively spliced transcripts:
# Survivin, which has a three-intron–four-exon structure in both the mouse and human.
# Survivin-2B, which has an insertion of an alternative exon 2.
# Survivin-Delta-Ex-3, which has exon 3 removed. The removal of exon 3 results in a frame shift that generates a unique carboxyl terminus with a new function. This new function may involve a nuclear localization signal. Moreover, a mitochondrial localization signal is also generated.
# Survivin-3B, which has an insertion of an alternative exon 3. | 1 | Applied and Interdisciplinary Chemistry |
Organ printing utilizes techniques similar to conventional 3D printing where a computer model is fed into a printer that lays down successive layers of plastics or wax until a 3D object is produced. In the case of organ printing, the material being used by the printer is a biocompatible plastic. The biocompatible plastic forms a scaffold that acts as the skeleton for the organ that is being printed. As the plastic is being laid down, it is also seeded with human cells from the patient's organ that is being printed for. After printing, the organ is transferred to an incubation chamber to give the cells time to grow. After a sufficient amount of time, the organ is implanted into the patient.
To many researchers the ultimate goal of organ printing is to create organs that can be fully integrated into the human body. Successful organ printing has the potential to impact several industries, notably artificial organs organ transplants, pharmaceutical research, and the training of physicians and surgeons. | 1 | Applied and Interdisciplinary Chemistry |
Sellar and Boreman have argued that this SNR improvement can be considered as a result of freedom from needing an exit slit inside the spectrometer, since an exit slit reduces the light collected by the detector by the same factor. | 0 | Theoretical and Fundamental Chemistry |
Semiquinones (or ubisemiquinones, if their origin is ubiquinone) are free radicals resulting from the removal of one hydrogen atom with its electron during the process of dehydrogenation of a hydroquinone, such as hydroquinone itself or catechol, to a quinone or alternatively the addition of a single hydrogen atom with its electron to a quinone. Semiquinones are highly unstable.
E.g. ubisemiquinone is the first of two stages in reducing the supplementary form of CoQ (ubiquinone) to its active form ubiquinol. | 1 | Applied and Interdisciplinary Chemistry |
Pesticide contamination can be long-term and have a significant impact on decomposition processes and nutrient cycling. Therefore, their degradation can be expensive and difficult.
The most commonly used fungi for helping in the degradation of such substances are white rot fungi, which, thanks to their extracellular ligninolytic enzymes like laccase and manganese peroxidase, are able to degrade high quantity of such components. Examples includes the insecticide endosulfan, imazalil, thiophanate methyl, ortho-phenylphenol, diphenylamine, chlorpyrifos in wastewater, and atrazine in clay-loamy soils. | 1 | Applied and Interdisciplinary Chemistry |
Recent advances in the understanding of biomolecules enabled their application to numerous fields like medicine, diagnostics, biocatalysis and materials. Synthetically modified biomolecules can have diverse functionalities, such as tracking cellular events, revealing enzyme function, determining protein biodistribution, imaging specific biomarkers, and delivering drugs to targeted cells. Bioconjugation is a crucial strategy that links these modified biomolecules with different substrates. Besides applications in biomedical research, bioconjugation has recently also gained importance in nanotechnology such as bioconjugated quantum dots. | 1 | Applied and Interdisciplinary Chemistry |
When a transverse force is applied to a beam, the result is variation in bending normal stresses along the length of the beam. This variation causes a horizontal shear stress within the beam that varies with distance from the neutral axis in the beam. The concept of complementary shear then dictates that a shear stress also exists across the cross section of the beam, in the direction of the original transverse force. As described above, in thin-walled structures, the variation along the thickness of the member can be neglected, so the shear stress across the cross section of a beam that is composed of thin-walled elements can be examined as shear flow, or the shear stress multiplied by the thickness of the element. | 1 | Applied and Interdisciplinary Chemistry |
Colloids can be classified as follows:
Homogeneous mixtures with a dispersed phase in this size range may be called colloidal aerosols, colloidal emulsions, colloidal suspensions, colloidal foams, colloidal dispersions, or hydrosols. | 0 | Theoretical and Fundamental Chemistry |
Upregulation refers to the increase in the number of receptor sites on the membrane. Estrogen and FSH upregulate LHCGR sites in preparation for ovulation. After ovulation, the luteinized ovary maintains LHCGR s that allow activation in case there is an implantation. Upregulation in males requires gene transcription to synthesize LH receptors within the cell cytoplasm. Some reasons as to why downregulated LH receptors are not upregulated are: lack of gene transcription, lack of RNA to protein conversion and lack of cell membrane targeted shipments from Golgi. | 1 | Applied and Interdisciplinary Chemistry |
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