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Molecular dynamics In the microcanonical ensemble, the system is isolated from changes in moles (N), volume (V), and energy (E). It corresponds to an adiabatic process with no heat exchange. A microcanonical molecular dynamics trajectory may be seen as an exchange of potential and kinetic energy, with total energy bein... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics If there is a large enough number of atoms, statistical temperature can be estimated from the "instantaneous temperature", which is found by equating the kinetic energy of the system to "nkT"/2 where n is the number of degrees of freedom of the system. A temperature-related phenomenon arises due to t... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics Popular methods to control temperature include velocity rescaling, the Nosé–Hoover thermostat, Nosé–Hoover chains, the Berendsen thermostat, the Andersen thermostat and Langevin dynamics. The Berendsen thermostat might introduce the flying ice cube effect, which leads to unphysical translations and r... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics A molecular dynamics simulation requires the definition of a potential function, or a description of the terms by which the particles in the simulation will interact. In chemistry and biology this is usually referred to as a force field and in materials physics as an interatomic potential. Potentials... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics When finer levels of detail are needed, potentials based on quantum mechanics are used; some methods attempt to create hybrid classical/quantum potentials where the bulk of the system is treated classically but a small region is treated as a quantum system, usually undergoing a chemical transformatio... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics To lower the computational cost, force fields employ numerical approximations such as shifted cutoff radii, reaction field algorithms, particle mesh Ewald summation, or the newer particle–particle-particle–mesh (P3M). Chemistry force fields commonly employ preset bonding arrangements (an exception be... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics The first term in the next equation is Coulomb's law for a pair of ions, the second term is the short-range repulsion explained by Pauli's exclusion principle and the final term is the dispersion interaction term. Usually, a simulation only includes the dipolar term, although sometimes the quadrupola... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics Other examples are the embedded-atom method (EAM), the EDIP, and the Tight-Binding Second Moment Approximation (TBSMA) potentials, where the electron density of states in the region of an atom is calculated from a sum of contributions from surrounding atoms, and the potential energy contribution is t... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics For homogenous liquids such as water, increased accuracy has been achieved through the inclusion of polarizability. Some promising results have also been achieved for proteins. However, it is still uncertain how to best approximate polarizability in a simulation. In classical molecular dynamics, one ... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics A significant advantage of using "ab initio" methods is the ability to study reactions that involve breaking or formation of covalent bonds, which correspond to multiple electronic states. QM (quantum-mechanical) methods are very powerful. However, they are computationally expensive, while the MM (cl... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics On the other hand, the simplest "ab initio" calculations typically scale O(n) or worse (restricted Hartree–Fock calculations have been suggested to scale ~O(n)). To overcome the limit, a small part of the system is treated quantum-mechanically (typically active-site of an enzyme) and the remaining sy... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics Examples for coarse graining (CG) methods are discontinuous molecular dynamics (CG-DMD) and Go-models. Coarse-graining is done sometimes taking larger pseudo-atoms. Such united atom approximations have been used in MD simulations of biological membranes. Implementation of such approach on systems whe... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics For example, instead of treating all four atoms of a CH methyl group explicitly (or all three atoms of CH methylene group), one represents the whole group with one pseudo-atom. It must, of course, be properly parameterized so that its van der Waals interactions with other groups have the proper dista... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics Solvents may influence the dynamic behavior of solutes via random collisions and by imposing a frictional drag on the motion of the solute through the solvent. The use of non-rectangular periodic boundary conditions, stochastic boundaries and solvent shells can all help reduce the number of solvent m... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics Spherically truncating the potential is also out of the question as unrealistic behaviour may be observed when the distance is close to the cut off distance. Steered molecular dynamics (SMD) simulations, or force probe simulations, apply forces to a protein in order to manipulate its structure by pul... | https://en.wikipedia.org/wiki?curid=198608 |
Molecular dynamics SMD was used to investigate the stability of Alzheimer's protofibrils, to study the protein ligand interaction in cyclin-dependent kinase 5 and even to show the effect of electric field on thrombin (protein) and aptamer (nucleotide) complex among many other interesting studies. is used in many fields... | https://en.wikipedia.org/wiki?curid=198608 |
Freezing is a phase transition where a liquid turns into a solid when its temperature is lowered below its freezing point. In accordance with the internationally established definition, freezing means the solidification phase change of a liquid or the liquid content of a substance, usually due to cooling. Although some... | https://en.wikipedia.org/wiki?curid=198824 |
Freezing Nucleation is the step wherein the molecules start to gather into clusters, on the nanometer scale, arranging in a defined and periodic manner that defines the crystal structure. The crystal growth is the subsequent growth of the nuclei that succeed in achieving the critical cluster size. In spite of the secon... | https://en.wikipedia.org/wiki?curid=198824 |
Freezing 15 K), and in the presence of nucleating substances the freezing point of water is close to the melting point, but in the absence of nucleators water can supercool to −40 °C (−40 °F, 233 K) before freezing. Under high pressure (2,000 atmospheres) water will supercool to as low as −70 °C (−94 °F, 203 K) before ... | https://en.wikipedia.org/wiki?curid=198824 |
Freezing Instead, there is a gradual change in their viscoelastic properties over a range of temperatures. Such materials are characterized by a glass transition that occurs at a glass transition temperature, which may be roughly defined as the "knee" point of the material's density vs. temperature graph. Because vitri... | https://en.wikipedia.org/wiki?curid=198824 |
Freezing Many plants undergo a process called hardening, which allows them to survive temperatures below 0 °C for weeks to months. The nematode "Haemonchus contortus" can survive 44 weeks frozen at liquid nitrogen temperatures. Other nematodes that survive at temperatures below 0 °C include "Trichostrongylus colubrifor... | https://en.wikipedia.org/wiki?curid=198824 |
Coding region The coding region of a gene, also known as the CDS (from "coding sequence"), is the portion of a gene's DNA or RNA that codes for protein. Studying the length, composition, regulation, splicing, structures, and functions of coding regions compared to non-coding regions over different species and time peri... | https://en.wikipedia.org/wiki?curid=198948 |
Coding region This was the first indication that there needed to be a distinction between the parts of the genome that code for protein, now called coding regions, and those that do not. The evidence suggests that there is a general interdependence between base composition patterns and coding region availability. The c... | https://en.wikipedia.org/wiki?curid=198948 |
Coding region There is also debate on whether the methods used, such as gene windows, to ascertain the relationship between GC-content and coding region are accurate and unbiased. In DNA, the coding region is flanked by the promoter sequence on the 5' end of the template strand and the termination sequence on the 3' en... | https://en.wikipedia.org/wiki?curid=198948 |
Coding region While the regulation of gene expression manages the abundance of RNA or protein made in a cell, the regulation of these mechanisms can be controlled by a regulatory sequence found before the open reading frame begins in a strand of DNA. The regulatory sequence will then determine the location and time tha... | https://en.wikipedia.org/wiki?curid=198948 |
Coding region There also exist nonsense mutations, where base alterations in the coding region code for a premature stop codon, producing a shorter final protein. Point mutations, or single base pair changes in the coding region, that code for different amino acids during translation, are called missense mutations. Oth... | https://en.wikipedia.org/wiki?curid=198948 |
Coding region While it is well known that the genome of one individual can have extensive differences when compared to the genome of another, recent research has found that some coding regions are highly constrained, or resistant to mutation, between individuals of the same species. This is similar to the concept of in... | https://en.wikipedia.org/wiki?curid=198948 |
Coding region CDS prediction is a subset of gene prediction, the latter also including prediction of DNA sequences that code not only for protein but also for other functional elements such as RNA genes and regulatory sequences. In both prokaryotes and eukaryotes, gene overlapping occurs relatively often in both DNA an... | https://en.wikipedia.org/wiki?curid=198948 |
Chemical equation A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side. The coefficients next to the symbols and formulae of entities are the absolute v... | https://en.wikipedia.org/wiki?curid=199040 |
Chemical equation It also indicates that two sodium molecules are required for every two hydrochloric acid molecules and the reaction will form two sodium chloride molecules and one diatomic molecule of hydrogen gas molecule for every two hydrochloric acid and two sodium molecules that react. The stoichiometric coeffic... | https://en.wikipedia.org/wiki?curid=199040 |
Chemical equation Therefore, the same charge must be present on both sides of the balanced equation. One balances a chemical equation by changing the scalar number for each chemical formula. Simple chemical equations can be balanced by inspection, that is, by trial and error. Another technique involves solving a system... | https://en.wikipedia.org/wiki?curid=199040 |
Chemical equation It can be balanced by putting a 2 before O, giving the balanced equation: This equation does not have any coefficients in front of CH and CO, since a coefficient of 1 is dropped. Generally, any chemical equation involving "J" different molecules can be written as: where "R" is the symbol for the "j-th... | https://en.wikipedia.org/wiki?curid=199040 |
Chemical equation The problem of balancing a chemical equation then becomes the problem of determining the "J"-dimensional null space of the composition matrix. It is important to note that only for "J"=1, will there be a unique solution. For "J">1 there will be an infinite number of solutions to the balancing problem,... | https://en.wikipedia.org/wiki?curid=199040 |
Chemical equation The net ionic equation of the proceeding reactions is: or, in "reduced" balanced form, In a neutralization or acid/base reaction, the net ionic equation will usually be: There are a few acid/base reactions that produce a precipitate in addition to the water molecule shown above. An example is the reac... | https://en.wikipedia.org/wiki?curid=199040 |
Rydberg constant In spectroscopy, the Rydberg constant, symbol formula_1 for heavy atoms or formula_2 for hydrogen, named after the Swedish physicist Johannes Rydberg, is a physical constant relating to the electromagnetic spectra of an atom. The constant first arose as an empirical fitting parameter in the Rydberg for... | https://en.wikipedia.org/wiki?curid=199121 |
Rydberg constant It is not perfectly accurate, but is a remarkably good approximation in many cases, and historically played an important role in the development of quantum mechanics. The Bohr model posits that electrons revolve around the atomic nucleus in a manner analogous to planets revolving around the sun. In the... | https://en.wikipedia.org/wiki?curid=199121 |
Rydberg constant Instead, the is inferred from measurements of atomic transition frequencies in three different atoms (hydrogen, deuterium, and antiprotonic helium). Detailed theoretical calculations in the framework of quantum electrodynamics are used to account for the effects of finite nuclear mass, fine structure, ... | https://en.wikipedia.org/wiki?curid=199121 |
VX (nerve agent) VX is an extremely toxic synthetic chemical compound in the organophosphorus class, specifically, a thiophosphonate. In the class of nerve agents, it was developed for military use in chemical warfare after translation of earlier discoveries of organophosphate toxicity in pesticide research. In its pur... | https://en.wikipedia.org/wiki?curid=199306 |
VX (nerve agent) it is not a "vapor hazard"). VX is considered an area denial weapon due to these physical and biochemical characteristics. As a chemical weapon, it is categorized as a weapon of mass destruction and is banned by the Chemical Weapons Convention of 1993, where production and stockpiling of VX exceeding p... | https://en.wikipedia.org/wiki?curid=199306 |
VX (nerve agent) To avoid a state of constant muscle contraction, the acetylcholine is then broken down (hydrolysed) into the inactive substances acetic acid and choline by AChE. VX blocks the action of AChE, resulting in an accumulation of acetylcholine in the space between the neuron and muscle cell. On a molecular l... | https://en.wikipedia.org/wiki?curid=199306 |
VX (nerve agent) Aging is a time-dependent side reaction (loss of an alkoxyl group) that occurs on nerve agents after phosphonylation and renders the nerve agent-acetylcholinesterase complex highly resistant to regeneration by any known antidote. Slower aging by VX suggests it should be possible to develop more effecti... | https://en.wikipedia.org/wiki?curid=199306 |
VX (nerve agent) VX can also be delivered in binary chemical weapons which mix in-flight to form the agent prior to release. Binary VX is referred to as VX2, and is created by mixing "O"-(2-diisopropylaminoethyl) "O′"-ethyl methylphosphonite (Agent QL) with elemental sulfur (Agent NE) as is done in the Bigeye aerial ch... | https://en.wikipedia.org/wiki?curid=199306 |
VX (nerve agent) The potentially fatal dose is only slightly higher than the dose having any effect at all, and the effects of a fatal dose are so rapid that there is little time for treatment. The median lethal dose (LD)—the exposure required to kill half of a tested population—as estimated for 70 kg human males via e... | https://en.wikipedia.org/wiki?curid=199306 |
VX (nerve agent) An individual known to have been exposed to a nerve-agent, or who exhibits definite signs or symptoms of nerve-agent exposure is generally given the antidotes atropine and pralidoxime (2-PAM), and in the case of convulsions an injected sedative/antiepileptic such as diazepam. In several nations the ner... | https://en.wikipedia.org/wiki?curid=199306 |
VX (nerve agent) The chemists Ranajit Ghosh and J. F. Newman discovered the V-series nerve agents at the British firm ICI in 1952, patenting diethyl "S"-2-diethylaminoethyl phosphonothioate (agent VG) in November 1952. Further commercial research on similar compounds ceased in 1955 when its lethality to humans was disc... | https://en.wikipedia.org/wiki?curid=199306 |
VX (nerve agent) After approximately 3.5 hours following initial administration of the agent, Sim suddenly became pale and delirious. The experiment was immediately terminated to preserve his life. In their conclusion, the researchers estimated that 2.12 μg/kg of VX delivered intravenously over the course of several ho... | https://en.wikipedia.org/wiki?curid=199306 |
VX (nerve agent) Two people were injured and one 28-year-old man died, who was the first victim of VX ever documented in the world at that time. The VX victim, whom Shoko Asahara had suspected as a spy, was attacked at 7:00 am on 12 December 1994 on the street in Osaka by Tomomitsu Niimi and another AUM member, who spr... | https://en.wikipedia.org/wiki?curid=199306 |
VX (nerve agent) The director of a non-proliferation research program of the Middlebury Institute of International Studies at Monterey stated that VX fumes would have killed the suspected attackers even if they had been wearing gloves, suggesting that the VX was applied as two non-lethal components that would mix to fo... | https://en.wikipedia.org/wiki?curid=199306 |
VX (nerve agent) Eric G. Gibson" was filled with 7,380 VX rockets and scuttled in of water off the coast of Atlantic City, New Jersey. Incineration was used for VX stockpile destruction starting in 1990 with Johnston Atoll Chemical Agent Disposal System in the North Pacific with other incineration plants following at D... | https://en.wikipedia.org/wiki?curid=199306 |
VX (nerve agent) will be treated by the Blue Grass Chemical Agent-Destruction Pilot Plant in Kentucky, part of the Program Executive Office, Assembled Chemical Weapons Alternatives program. The program was established as an alternative to the incineration process successfully used by the Army Chemical Materials Agency,... | https://en.wikipedia.org/wiki?curid=199306 |
VX (nerve agent) Other references to VX are found in the 2012 film "It's a Disaster" in which it is revealed that a nearby "dirty bomb" attack was in fact a VX attack, prompting the three couples to contemplate a suicide pact, as well as the 2015 film "", where in the beginning scene Ethan Hunt steals VX nerve gas from... | https://en.wikipedia.org/wiki?curid=199306 |
Primary standard A primary standard in metrology is a standard that is sufficiently accurate such that it is not calibrated by or subordinate to other standards. Primary standards are defined via other quantities like length, mass and time. Primary standards are used to calibrate other standards referred to as working ... | https://en.wikipedia.org/wiki?curid=200069 |
Crista A crista (; plural cristae) is a fold in the inner membrane of a mitochondrion. The name is from the Latin for "crest" or "plume", and it gives the inner membrane its characteristic wrinkled shape, providing a large amount of surface area for chemical reactions to occur on. This aids aerobic cellular respiration... | https://en.wikipedia.org/wiki?curid=200195 |
Crista As those electrons travel farther through the electron transport chain in the inner membrane, energy is gradually released and used to pump the hydrogen ions from the splitting of NADH and FADH into the space between the inner membrane and the outer membrane (called the intermembrane space), creating an electroc... | https://en.wikipedia.org/wiki?curid=200195 |
Crista As a result, 10 NADH molecules (from glycolysis and the Krebs cycle), along with 2 FADH molecules, can form a total of 34 ATPs during aerobic respiration (from a single electron transport chain). This means that combined with the Krebs Cycle and glycolysis, the efficiency for the electron transport chain is abou... | https://en.wikipedia.org/wiki?curid=200195 |
Lactic acid fermentation is a metabolic process by which glucose and other six-carbon sugars (also, disaccharides of six-carbon sugars, e.g. sucrose or lactose) are converted into cellular energy and the metabolite lactate, which is lactic acid in solution. It is an anaerobic fermentation reaction that occurs in some b... | https://en.wikipedia.org/wiki?curid=200201 |
Lactic acid fermentation With a difference of some years, each of them described, together with colleagues, the chemical structure of the lactic acid molecule as we know it today. They had a purely chemical understanding of the fermentation process, which means that you can't see it using a microscope, and that it can ... | https://en.wikipedia.org/wiki?curid=200201 |
Lactic acid fermentation " Although this chemical process had not been properly described before Pasteur's work, people had been using microbial lactic acid fermentation for food production much earlier. Chemical analysis of archeological finds show that milk fermentation uses predate the historical period; its first a... | https://en.wikipedia.org/wiki?curid=200201 |
Lactic acid fermentation The idea of this theory is that the women of these first settled farmer clans could shorten the time between two children thanks to the additional lactose uptake from milk consumption. This factor may have given them an important advantage to out-compete the hunter-gatherer societies. With the ... | https://en.wikipedia.org/wiki?curid=200201 |
Lactic acid fermentation For instance, the fattier part on the top, the "deež", is seen as the most valuable part and is therefore often used to honor guests. Very important with often a traditional meaning as well are fermentation products of mare milk, like for example the slightly-alcoholic yogurt kumis. Consumption... | https://en.wikipedia.org/wiki?curid=200201 |
Lactic acid fermentation However, in rural and poorer regions it is still of great importance. Homofermentative bacteria convert glucose to two molecules of lactate and use this reaction to perform substrate-level phosphorylation to make two molecules of ATP: Heterofermentative bacteria produce less lactate and less AT... | https://en.wikipedia.org/wiki?curid=200201 |
Lactic acid fermentation A product prepared by lactic acid bacteria (LAB) fermentation of sugars present in the pieces of fruits and vegetables. Traditionally, non-iodized salt is introduced to the vegetables through a brine, which inhibits spoilage but allows the growth of lactobacillus. The prepared product is rich i... | https://en.wikipedia.org/wiki?curid=200201 |
Lactic acid fermentation The primary bacteria used are typically "Lactobacillus bulgaricus" and "Streptococcus thermophilus", and United States as well as European law requires all yogurts to contain these two cultures (though others may be added as probiotic cultures). These bacteria produce lactic acid in the milk cu... | https://en.wikipedia.org/wiki?curid=200201 |
Lactic acid fermentation A lack of oxygen inside of the muscle cells resulted in lactic acid fermentation. This is due to the cell needing oxygen as a terminal electron acceptor to produce ATP. Without oxygen present, the cells needed to create energy through a different method. Lactic acid, or lactate and H+ were crea... | https://en.wikipedia.org/wiki?curid=200201 |
Lactic acid fermentation If the pH in the vagina becomes too basic, more lactic acid will be produced to lower the pH back to a more acidic level. Lactic acid producing bacteria also act as a protective barrier against possible pathogens such as bacterial vaginosis and vaginitis species, different fungi, and protozoa t... | https://en.wikipedia.org/wiki?curid=200201 |
Sodium nitrate is the chemical compound with the formula . This alkali metal nitrate salt is also known as Chile saltpeter (large deposits of which were historically mined in Chile) to distinguish it from ordinary saltpeter, potassium nitrate. The mineral form is also known as nitratine, nitratite or soda niter. is a w... | https://en.wikipedia.org/wiki?curid=200310 |
Sodium nitrate Nitrates accumulate on land through marine-fog precipitation and sea-spray oxidation/desiccation followed by gravitational settling of airborne NaNO, KNO, NaCl, NaSO, and I, in the hot-dry desert atmosphere. El Niño/La Niña extreme aridity/torrential rain cycles favor nitrates accumulation through both a... | https://en.wikipedia.org/wiki?curid=200310 |
Sodium nitrate The former Chilean saltpeter mining communities of Humberstone and Santa Laura were declared Unesco World Heritage sites in 2005. is also synthesized industrially by neutralizing nitric acid with sodium carbonate or sodium bicarbonate: or also by neutralizing it with sodium hydroxide (however, this react... | https://en.wikipedia.org/wiki?curid=200310 |
Sodium nitrate A mixture of sodium nitrate, calcium nitrate and potassium nitrate is used as energy-storage material in prototype plants, such as Andasol Solar Power Station and the Archimedes project. It is also used in the wastewater industry for facultative microorganism respiration. Nitrosomonas, a genus of microor... | https://en.wikipedia.org/wiki?curid=200310 |
Sodium nitrate One of the reasons that processed meat increases the risk of colon cancer is its content of nitrate. A small amount of the nitrate added to meat as a preservative breaks down into nitrite, in addition to any nitrite that may also be added. The nitrite then reacts with protein-rich foods (such as meat) to... | https://en.wikipedia.org/wiki?curid=200310 |
KREEP KREEP, an acronym built from the letters K (the atomic symbol for potassium), REE (rare-earth elements) and P (for phosphorus), is a geochemical component of some lunar impact breccia and basaltic rocks. Its most significant feature is somewhat enhanced concentration of a majority of so-called "incompatible" elem... | https://en.wikipedia.org/wiki?curid=200719 |
KREEP As the crystallization of this liquid rock proceeded, minerals such as olivine and pyroxene precipitated and sank to the bottom to form the lunar mantle. After the solidification was about 75% complete, the material anorthositic plagioclase began to crystallize, and because of its low density, it floated, forming... | https://en.wikipedia.org/wiki?curid=200719 |
KREEP The enhancement of heat-producing radioactive elements within the crust (and/or the mantle) of the Procellarum Terrane is almost certainly responsible for the longevity and intensity of mare volcanism on the nearside of the Moon. | https://en.wikipedia.org/wiki?curid=200719 |
Drift velocity In physics a drift velocity is the average velocity attained by charged particles, such as electrons, in a material due to an electric field. In general, an electron in a conductor will propagate randomly at the Fermi velocity, resulting in an average velocity of zero. Applying an electric field adds to ... | https://en.wikipedia.org/wiki?curid=200919 |
Drift velocity The formula for evaluating the drift velocity of charge carriers in a material of constant cross-sectional area is given by: where is the drift velocity of electrons, is the current density flowing through the material, is the charge-carrier number density, and is the charge on the charge-carrier. This c... | https://en.wikipedia.org/wiki?curid=200919 |
Drift velocity By comparison, the Fermi flow velocity of these electrons (which, at room temperature, can be thought of as their approximate velocity in the absence of electric current) is around . | https://en.wikipedia.org/wiki?curid=200919 |
Magnetostriction (cf. electrostriction) is a property of magnetic materials that causes them to change their shape or dimensions during the process of magnetization. The variation of materials' magnetization due to the applied magnetic field changes the magnetostrictive strain until reaching its saturation value, λ. Th... | https://en.wikipedia.org/wiki?curid=201002 |
Magnetostriction Since different crystal directions are associated with different lengths this effect induces a strain in the material. The reciprocal effect, the change of the magnetic susceptibility (response to an applied field) of a material when subjected to a mechanical stress, is called the Villari effect. Two o... | https://en.wikipedia.org/wiki?curid=201002 |
Magnetostriction The effect is responsible for the familiar "electric hum" () which can be heard near transformers and high power electrical devices. Cobalt exhibits the largest room-temperature magnetostriction of a pure element at 60 microstrains. Among alloys, the highest known magnetostriction is exhibited by Terfe... | https://en.wikipedia.org/wiki?curid=201002 |
Magnetostriction Cobalt ferrite, CoFeO (CoO·FeO), is also mainly used for its magnetostrictive applications like sensors and actuators thanks to its high saturation magnetostriction (~200 parts per million). Having no rare-earth elements, it is a good substitute for Terfenol-D. Moreover, its magnetostrictive properties... | https://en.wikipedia.org/wiki?curid=201002 |
Magnetostriction For a polycrystalline alloy, an established formula for the magnetostriction λ from known directional microstrain measurements is: λ = 1/5(2λ+3λ) During subsequent hot rolling and recrystallization steps, particle strengthening occurs in which the particles introduce a “pinning” force at grain boundari... | https://en.wikipedia.org/wiki?curid=201002 |
Matteucci effect is one of the magnetomechanical effects, which is thermodynamically inverse to Wiedemann effect. It is observable in amorphous wires with helical domain structure, which can be obtained by twisting the wire, or annealing under twist. The effect is most distinct in the so-called 'dwarven alloys' (called... | https://en.wikipedia.org/wiki?curid=201078 |
Wiedemann effect The twisting of a ferromagnetic rod through which an electric current is flowing when the rod is placed in a longitudinal magnetic field. It was discovered by the German physicist Gustav Wiedemann in 1858 . The is one of the manifestations of magnetostriction in a field formed by the combination of a l... | https://en.wikipedia.org/wiki?curid=201080 |
RNA polymerase (ribonucleic acid polymerase), abbreviated RNAP or RNApol, officially DNA-directed RNA polymerase, is an enzyme that synthesizes RNA from a DNA template. RNAP locally opens the double-stranded DNA (usually about four turns of the double helix) so that one strand of the exposed nucleotides can be used as ... | https://en.wikipedia.org/wiki?curid=201268 |
RNA polymerase The latter is found in phages as well as eukaryotic chloroplasts and mitochondria, and is related to modern DNA polymerases. Eukaryotic and archaeal RNAPs have more subunits than bacterial ones do, and are controlled differently. Bacteria and archaea only have one RNA polymerase. Eukaryotes have multiple... | https://en.wikipedia.org/wiki?curid=201268 |
RNA polymerase Eukaryotic and archaeal RNA polymerases have a similar core structure and work in a similar manner, although they have many extra subunits. All RNAPs contain metal cofactors, in particular zinc and magnesium cations which aid in the transcription process. Control of the process of gene transcription affe... | https://en.wikipedia.org/wiki?curid=201268 |
RNA polymerase Such specific interactions explain why RNAP prefers to start transcripts with ATP (followed by GTP, UTP, and then CTP). In contrast to DNA polymerase, RNAP includes helicase activity, therefore no separate enzyme is needed to unwind DNA. binding in bacteria involves the sigma factor recognizing the core ... | https://en.wikipedia.org/wiki?curid=201268 |
RNA polymerase Because regions of DNA in front of RNAP are unwound, there are compensatory positive supercoils. Regions behind RNAP are rewound and negative supercoils are present. then starts to synthesize the initial DNA-RNA heteroduplex, with ribonucleotides base-paired to the template DNA strand according to Watson... | https://en.wikipedia.org/wiki?curid=201268 |
RNA polymerase The paused transcribing complex has two options: (1) release the nascent transcript and begin anew at the promoter or (2) reestablish a new 3'OH on the nascent transcript at the active site via RNA polymerase's catalytic activity and recommence DNA scrunching to achieve promoter escape. Abortive initiati... | https://en.wikipedia.org/wiki?curid=201268 |
RNA polymerase Proofreading begins with separation of the mis-incorporated nucleotide from the DNA template. This pauses transcription. The polymerase then backtracks by one position and cleaves the dinucleotide that contains the mismatched nucleotide. In the this occurs at the same active site used for polymerization ... | https://en.wikipedia.org/wiki?curid=201268 |
RNA polymerase Given that DNA and RNA polymerases both carry out template-dependent nucleotide polymerization, it might be expected that the two types of enzymes would be structurally related. However, x-ray crystallographic studies of both types of enzymes reveal that, other than containing a critical Mg ion at the ca... | https://en.wikipedia.org/wiki?curid=201268 |
RNA polymerase All are structurally and mechanistically related to each other and to bacterial RNAP: Eukaryotic chloroplasts contain an RNAP very highly similar to bacterial RNAP ("plastid-encoded polymerase, PEP"). They use sigma factors encoded in the nuclear genome. Chloroplast also contain a second, structurally an... | https://en.wikipedia.org/wiki?curid=201268 |
RNA polymerase There is an additional subunit dubbed Rpo13; together with Rpo5 it occupies a space filled by an insertion found in bacterial β' subunits (1,377–1,420 in "Taq"). An earlier, lower-resolution study on "S. solfataricus" structure did not find Rpo13 and only assigned the space to Rpo5/Rpb5. Rpo3 is notable ... | https://en.wikipedia.org/wiki?curid=201268 |
RNA polymerase This occurs in negative strand RNA viruses and dsRNA viruses, both of which exist for a portion of their life cycle as double-stranded RNA. However, some positive strand RNA viruses, such as poliovirus, also contain RNA-dependent RNAP. RNAP was discovered independently by Charles Loe, Audrey Stevens, and... | https://en.wikipedia.org/wiki?curid=201268 |
Protein tag Protein tags are peptide sequences genetically grafted onto a recombinant protein. Often these tags are removable by chemical agents or by enzymatic means, such as proteolysis or intein splicing. Tags are attached to proteins for various purposes. Affinity tags are appended to proteins so that they can be p... | https://en.wikipedia.org/wiki?curid=2520961 |
Protein tag These tags are particularly useful for western blotting, immunofluorescence and immunoprecipitation experiments, although they also find use in antibody purification. Fluorescence tags are used to give visual readout on a protein. GFP and its variants are the most commonly used fluorescence tags. More advan... | https://en.wikipedia.org/wiki?curid=2520961 |
Free induction decay In Fourier transform nuclear magnetic resonance spectroscopy, free induction decay (FID) is the observable NMR signal generated by non-equilibrium nuclear spin magnetization precessing about the magnetic field (conventionally along z). This non-equilibrium magnetization can be induced, generally by... | https://en.wikipedia.org/wiki?curid=2521046 |
Multiferroics are defined as materials that exhibit more than one of the primary ferroic properties in the same phase: While ferroelectric ferroelastics and ferromagnetic ferroelastics are formally multiferroics, these days the term is usually used to describe the "magnetoelectric multiferroics" that are simultaneously... | https://en.wikipedia.org/wiki?curid=2522070 |
Multiferroics Particularly key early works were the discovery of large ferroelectric polarization in epitaxially grown thin films of magnetic BiFeO, the observation that the non-collinear magnetic ordering in orthorhombic TbMnO and TbMnO causes ferroelectricity, and the identification of unusual improper ferroelectrici... | https://en.wikipedia.org/wiki?curid=2522070 |
Multiferroics One is piezomagnetism, which consists of linear coupling between a magnetic field in a solid and a deformation (analogous to piezoelectricity). The other is a linear coupling between magnetic and electric fields in a media, which would cause, for example, a magnetization proportional to an electric field.... | https://en.wikipedia.org/wiki?curid=2522070 |
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