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Atomic force microscopy A longer beam path increases the motion of the reflected spot on the photodiodes, but also widens the spot by the same amount due to diffraction, so that the same amount of optical power is moved from one photodiode to the other. The 'optical leverage' (output signal of the detector divided by d... | https://en.wikipedia.org/wiki?curid=227982 |
Atomic force microscopy The tube scanner can move the sample in the "x", "y", and "z" directions using a single tube piezo with a single interior contact and four external contacts. An advantage of the tube scanner compared to the original tripod design, is better vibrational isolation, resulting from the higher resona... | https://en.wikipedia.org/wiki?curid=227982 |
Atomic force microscopy This problem can be circumvented by adding a linear sensor to the sample stage or piezo stage to detect the true movement of the piezo. Deviations from ideal movement can be detected by the sensor and corrections applied to the piezo drive signal to correct for non-linear piezo movement. This de... | https://en.wikipedia.org/wiki?curid=227982 |
Atomic force microscopy While an electron microscope needs an expensive vacuum environment for proper operation, most AFM modes can work perfectly well in ambient air or even a liquid environment. This makes it possible to study biological macromolecules and even living organisms. In principle, AFM can provide higher r... | https://en.wikipedia.org/wiki?curid=227982 |
Atomic force microscopy One method of improving the scanned area size for AFM is by using parallel probes in a fashion similar to that of millipede data storage. The scanning speed of an AFM is also a limitation. Traditionally, an AFM cannot scan images as fast as an SEM, requiring several minutes for a typical scan, w... | https://en.wikipedia.org/wiki?curid=227982 |
Atomic force microscopy As with any other imaging technique, there is the possibility of image artifacts, which could be induced by an unsuitable tip, a poor operating environment, or even by the sample itself, as depicted on the right. These image artifacts are unavoidable; however, their occurrence and effect on resu... | https://en.wikipedia.org/wiki?curid=227982 |
Atomic force microscopy Studies have taken advantage of AFM to obtain further information on the behavior of live cells in biological media. Real-time atomic force spectroscopy (or nanoscopy) and dynamic atomic force spectroscopy have been used to study live cells and membrane proteins and their dynamic behavior at hig... | https://en.wikipedia.org/wiki?curid=227982 |
Charles Coulson Charles Alfred Coulson (13 December 1910 – 7 January 1974) was a British applied mathematician, theoretical chemist and religious author. His major scientific work was as a pioneer of the application of the quantum theory of valency to problems of molecular structure, dynamics and reactivity. He was als... | https://en.wikipedia.org/wiki?curid=228184 |
Charles Coulson His brother John also excelled at school, and went on to become Professor of Chemical Engineering at Newcastle University, and author of a major series of texts on chemical engineering. At Cambridge, Coulson first studied the Mathematics Tripos. He was awarded a College Senior Scholarship during his stu... | https://en.wikipedia.org/wiki?curid=228184 |
Charles Coulson On the social side, Eileen Florence Burrett was studying in Cambridge to become a school teacher when Charles was an undergraduate. They came together in meetings of the University Methodists. They married in 1938. In 1939, Coulson was appointed as senior lecturer in mathematics at University College, D... | https://en.wikipedia.org/wiki?curid=228184 |
Charles Coulson It extolled his breadth of interests that took in the action of radiation on bacteria and the theory of liquids and solutions, besides the molecular orbital treatment of small molecules and ions, the approximation methods needed for large organic molecules for studies of bond lengths in coronene and con... | https://en.wikipedia.org/wiki?curid=228184 |
Charles Coulson properties of electrolytes and colloidal solutions, including ... electrophoresis ... more than one hundred papers have been published during the past five years." Coulson's group consisted of (1) graduate students who conducted research on electronic structure and valence theory, for a Ph.D. degree dir... | https://en.wikipedia.org/wiki?curid=228184 |
Charles Coulson In 1952, Coulson was appointed Rouse Ball Professor of Mathematics and Fellow of Wadham College at the University of Oxford. The chair was held previously by E. A. Milne, the mathematician and astrophysicist, and Roger Penrose succeeded Coulson. His inaugural lecture expressed the following view of appl... | https://en.wikipedia.org/wiki?curid=228184 |
Charles Coulson Coulson apparently coined the phrase God of the gaps. Coulson believed religious faith was essential for the responsible use of science. He was a pacifist and conscientious objector, but championed the development of nuclear energy. He encouraged scientists to help improve Third World food production. H... | https://en.wikipedia.org/wiki?curid=228184 |
Vanillin is an organic compound with the molecular formula . It is a phenolic aldehyde. Its functional groups include aldehyde, hydroxyl, and ether. It is the primary component of the extract of the vanilla bean. Synthetic vanillin is now used more often than natural vanilla extract as a flavoring agent in foods, bever... | https://en.wikipedia.org/wiki?curid=228190 |
Vanillin Europeans became aware of both chocolate and vanilla around 1520. was first isolated as a relatively pure substance in 1858 by Nicolas-Theodore Gobley, who obtained it by evaporating a vanilla extract to dryness and recrystallizing the resulting solids from hot water. In 1874, the German scientists Ferdinand T... | https://en.wikipedia.org/wiki?curid=228190 |
Vanillin Today, approximately 15% of the world's production of vanillin is still made from lignin wastes, while approximately 85% synthesized in a two-step process from the petrochemical precursors guaiacol and glyoxylic acid. Beginning in 2000, Rhodia began marketing biosynthetic vanillin prepared by the action of mic... | https://en.wikipedia.org/wiki?curid=228190 |
Vanillin Natural vanillin is extracted from the seed pods of "Vanilla planifolia", a vining orchid native to Mexico, but now grown in tropical areas around the globe. Madagascar is presently the largest producer of natural vanillin. As harvested, the green seed pods contain vanillin in the form of its β--glucoside; the... | https://en.wikipedia.org/wiki?curid=228190 |
Vanillin biosynthesis is generally agreed to be part of the phenylpropanoid pathway starting with -phenylalanine, which is deaminated by phenylalanine ammonia lyase (PAL) to form t-cinnamic acid. The para position of the ring is then hydroxylated by the cytochrome P450 enzyme cinnamate 4-hydroxylase (C4H/P450) to creat... | https://en.wikipedia.org/wiki?curid=228190 |
Vanillin The demand for vanilla flavoring has long exceeded the supply of vanilla beans. , the annual demand for vanillin was 12,000 tons, but only 1,800 tons of natural vanillin were produced. The remainder was produced by chemical synthesis. was first synthesized from eugenol (found in oil of clove) in 1874–75, less ... | https://en.wikipedia.org/wiki?curid=228190 |
Vanillin Wood-based vanillin is produced by copper-catalyzed oxidation of the lignin structures in lignosulfonates under alkaline conditions and is claimed by the manufacturing company to be preferred by their customers due to, among other reasons, its much lower carbon footprint than petrochemically synthesized vanill... | https://en.wikipedia.org/wiki?curid=228190 |
Vanillin Vanillin–HCl staining can be used to visualize the localisation of tannins in cells. has been used as a chemical intermediate in the production of pharmaceuticals, cosmetics, and other fine chemicals. In 1970, more than half the world's vanillin production was used in the synthesis of other chemicals. As of 20... | https://en.wikipedia.org/wiki?curid=228190 |
John Newlands (chemist) John Alexander Reina Newlands (26 November 1837 – 29 July 1898) was a British chemist who worked concerning the periodicity of elements. Newlands was born in London in England, at West Square in Lambeth, the son of a Scottish Presbyterian minister and his Italian wife. He was home-schooled by hi... | https://en.wikipedia.org/wiki?curid=228425 |
John Newlands (chemist) Groups were shown going across the table, with Periods going down – the opposite from the modern form of the periodic table. The incompleteness of the table alluded to the possible existence of additional, undiscovered elements. However, the Law of Octaves was ridiculed by some of Newlands' cont... | https://en.wikipedia.org/wiki?curid=228425 |
Hot-dip galvanization is a form of galvanization. It is the process of coating iron and steel with zinc, which alloys with the surface of the base metal when immersing the metal in a bath of molten zinc at a temperature of around . When exposed to the atmosphere, the pure zinc (Zn) reacts with oxygen (O) to form zinc o... | https://en.wikipedia.org/wiki?curid=229091 |
Hot-dip galvanization Electrogalvanized sheet steel is often used in automotive manufacturing to enhance the corrosion performance of exterior body panels; this is, however, a completely different process which tends to achieve lower coating thicknesses of zinc. Like other corrosion protection systems, galvanizing prot... | https://en.wikipedia.org/wiki?curid=229091 |
Hot-dip galvanization A third, declining method is to use low Z5 grade zinc. Steel strip can be hot-dip galvanized in a continuous line. Hot-dip galvanized steel strip (also sometimes loosely referred to as galvanized iron) is extensively used for applications requiring the strength of steel combined with the resistanc... | https://en.wikipedia.org/wiki?curid=229091 |
Hot-dip galvanization In 1836, French chemist Stanislas Sorel obtained a patent for a method of coating iron with zinc, after first cleaning it with 9% sulfuric acid (HSO) and fluxing it with ammonium chloride (NHCl). A hot-dip galvanized coating is relatively easier and cheaper to specify than an organic paint coating... | https://en.wikipedia.org/wiki?curid=229091 |
Matter wave Matter waves are a central part of the theory of quantum mechanics, being an example of wave–particle duality. All matter exhibits wave-like behavior. For example, a beam of electrons can be diffracted just like a beam of light or a water wave. In most cases, however, the wavelength is too small to have a p... | https://en.wikipedia.org/wiki?curid=229104 |
Matter wave In 1900, this division was exposed to doubt, when, investigating the theory of black-body radiation, Max Planck proposed that light is emitted in discrete quanta of energy. It was thoroughly challenged in 1905. Extending Planck's investigation in several ways, including its connection with the photoelectric... | https://en.wikipedia.org/wiki?curid=229104 |
Matter wave In 1926, Erwin Schrödinger published an equation describing how a matter wave should evolve – the matter wave analogue of Maxwell's equations — and used it to derive the energy spectrum of hydrogen. Matter waves were first experimentally confirmed to occur in George Paget Thomson's cathode ray diffraction e... | https://en.wikipedia.org/wiki?curid=229104 |
Matter wave Just as the photoelectric effect demonstrated the particle nature of light, the Davisson–Germer experiment showed the wave-nature of matter, and completed the theory of wave–particle duality. For physicists this idea was important because it meant that not only could any particle exhibit wave characteristic... | https://en.wikipedia.org/wiki?curid=229104 |
Matter wave The effect has also been used to explain the spatial version of the quantum Zeno effect, in which an otherwise unstable object may be stabilised by rapidly repeated observations. Recent experiments even confirm the relations for molecules and even macromolecules that otherwise might be supposed too large to... | https://en.wikipedia.org/wiki?curid=229104 |
Matter wave Using two formulas from special relativity, one for the relativistic momentum and one for the relativistic mass energy allows the equations to be written as where formula_11 denotes the particle's rest mass, formula_12 its velocity, formula_13 the Lorentz factor, and formula_14 the speed of light in a vacuu... | https://en.wikipedia.org/wiki?curid=229104 |
Matter wave For a free non-relativistic particle it follows that where is the mass of the particle and its velocity. Also in special relativity we find that where is the rest mass of the particle and is the speed of light in a vacuum. But (see below), using that the phase velocity is , therefore where is the velocity o... | https://en.wikipedia.org/wiki?curid=229104 |
Matter wave Likewise, the relation between group/particle velocity and phase velocity is given in frame-independent form by: formula_25 where The physical reality underlying de Broglie waves is a subject of ongoing debate. Some theories treat either the particle or the wave aspect as its fundamental nature, seeking to ... | https://en.wikipedia.org/wiki?curid=229104 |
Matter wave In 1955, Heisenberg reiterated this: It is mentioned above that the "displaced quantity" of the Schrödinger wave has values that are dimensionless complex numbers. One may ask what is the physical meaning of those numbers. According to Heisenberg, rather than being of some ordinary physical quantity such as... | https://en.wikipedia.org/wiki?curid=229104 |
Matter wave But in the account of quantum mechanics, a 'point' refers to a configuration of the system at an instant of time, every particle of the system being in a sense present in every 'point' of configuration space, each particle at such a 'point' being located possibly at a different position in ordinary physical... | https://en.wikipedia.org/wiki?curid=229104 |
Matter wave He used the special theory of relativity to find, in the frame of the observer of the electron energy packet that is moving with velocity formula_12, that its frequency was apparently reduced to Then using the same notation as above. The quantity formula_32 is the velocity of what de Broglie called the "pha... | https://en.wikipedia.org/wiki?curid=229104 |
Effusion In physics and chemistry, effusion is the process in which a gas escapes from a container through a hole of diameter considerably smaller than the mean free path of the molecules. Such a hole is often described as a "pinhole" and the escape of the gas is due to the pressure difference between the container and... | https://en.wikipedia.org/wiki?curid=229619 |
Effusion The average velocity of effused particles is: formula_6 Combined with the effusive flow rate, the recoil/thrust force on the system itself is: formula_7 An example is the recoil force on a balloon with a small punched hole flying in vacuum. By the kinetic theory of gases, the kinetic energy for a gas at a temp... | https://en.wikipedia.org/wiki?curid=229619 |
Effusion Gases with a lower molecular weight effuse more rapidly than gases with a higher molecular weight, so that the "number" of lighter molecules passing through the hole per unit time is greater. This is why a balloon filled with low molecular weight helium ("M" = 4) deflates faster than an equivalent balloon full... | https://en.wikipedia.org/wiki?curid=229619 |
Effusion The heat of sublimation can also be determined by measuring the vapor pressure as a function of temperature, using the Clausius–Clapeyron relation. | https://en.wikipedia.org/wiki?curid=229619 |
Molality Molality, also called molal concentration, is a measure of the concentration of a in a solution in terms of amount of substance in a specified amount of mass of the solvent. This contrasts with the definition of molarity which is based on a specified volume of solution. A commonly used unit for molality in che... | https://en.wikipedia.org/wiki?curid=229643 |
Molality The SI unit for molality is moles per kilogram of solvent. A solution with a molality of 3 mol/kg is often described as "3 molal", "3 m" or "3 "m"". However, following the SI system of units, the National Institute of Standards and Technology, the United States authority on measurement, considers the term "mol... | https://en.wikipedia.org/wiki?curid=229643 |
Molality If there is only one pure liquid substance in a mixture, the choice is clear, but not all solutions are this clear-cut: in an alcohol–water solution, either one could be called the solvent; in an alloy, or solid solution, there is no clear choice and all constituents may be treated alike. In such situations, m... | https://en.wikipedia.org/wiki?curid=229643 |
Molality More generally, for an "n"-solute/one-solvent solution, letting "x" be the mole fraction of the "i"th solute, where "x" is the mole fraction of the solvent, expressible both as a function of the molalities as well as a function of the other mole fractions: The conversions to and from the molar concentration, "... | https://en.wikipedia.org/wiki?curid=229643 |
Molality 20 mass fractions of 70% HNO, 49% HF, and HO, where the percentages refer to mass fractions of the bottled acids carrying a balance of HO. The first step is determining the mass fractions of the constituents: The approximate molar masses in kg/mol are First derive the molality of the solvent, in mol/kg, and us... | https://en.wikipedia.org/wiki?curid=229643 |
Molality In this case the first equality from above is modified with the mean molar mass M of the pseudosolute instead of the molar mass of the single solute: The sum of products molalities - apparent molar volumes of solutes in their binary solutions equals the product between the sum of molalities of solutes and appa... | https://en.wikipedia.org/wiki?curid=229643 |
Copper interconnects In semiconductor technology, copper interconnects are used in silicon integrated circuits (ICs) to reduce propagation delays and power consumption. Since copper is a better conductor than aluminium, ICs using copper for their interconnects can have interconnects with narrower dimensions, and use le... | https://en.wikipedia.org/wiki?curid=230641 |
Copper interconnects A thick coating of copper that significantly overfills the trenches is deposited on the insulator, and chemical-mechanical planarization (CMP) is used to remove the copper (known as "overburden") that extends above the top of the insulating layer. Copper sunken within the trenches of the insulating... | https://en.wikipedia.org/wiki?curid=230641 |
Copper interconnects The thickness of the barrier film is also quite important; with too thin a layer, the copper contacts poison the very devices that they connect to; with too thick a layer, the stack of two barrier metal films and a copper conductor have a greater total resistance than aluminium interconnects, elimi... | https://en.wikipedia.org/wiki?curid=230641 |
Copper interconnects Resistance to electromigration, the process by which a metal conductor changes shape under the influence of an electric current flowing through it and which eventually leads to the breaking of the conductor, is significantly better with copper than with aluminium. This improvement in electromigrati... | https://en.wikipedia.org/wiki?curid=230641 |
Sea salt is salt that is produced by the evaporation of seawater. It is used as a seasoning in foods, cooking, cosmetics and for preserving food. It is also called bay salt, solar salt, or salt. Like mined rock salt, production of sea salt has been dated to prehistoric times. There is no scientific evidence that consum... | https://en.wikipedia.org/wiki?curid=231065 |
Sea salt An ancient or medieval saltern was established where there was: In this way, salt marsh, pasture (salting), and salt works (saltern) enhanced each other economically. This was the pattern during the Roman and medieval periods around The Wash, in eastern England. There, the tide brought the brine, the extensive... | https://en.wikipedia.org/wiki?curid=231065 |
Sea salt In applications that retain sea salt's coarser texture, it can provide a different mouth feel, and may change flavor due to its different rate of dissolution. The mineral content also affects the taste. The colors and variety of flavors are due to local clays and algae found in the waters the salt is harvested... | https://en.wikipedia.org/wiki?curid=231065 |
Sea salt has also been shown to be contaminated by fungi that can cause food spoilage as well as some that may be mycotoxigenic. In traditional Korean cuisine, jugyeom (죽염, 竹鹽), which means "bamboo salt", is prepared by roasting salt at temperatures between 800 and 2000 °C in a bamboo container plugged with mud at both... | https://en.wikipedia.org/wiki?curid=231065 |
Detasheet is a flexible rubberized explosive, somewhat similar to plastic explosives, originally manufactured by DuPont. Its ingredients are PETN with nitrocellulose and a binder. It was manufactured in thin flexible sheets with a rubbery texture, technically known as a rubberized explosive and is generally colored eit... | https://en.wikipedia.org/wiki?curid=231224 |
Freon ( ) is a registered trademark of The Chemours Company, which uses it for a number of halocarbon products. They are stable, nonflammable, low toxicity gases or liquids which have generally been used as refrigerants and as aerosol propellants. These include the chlorofluorocarbons (CFCs) that cause ozone depletion ... | https://en.wikipedia.org/wiki?curid=232280 |
Freon Their product was dichlorodifluoromethane and is now designated "Freon-12", "R-12", or "CFC-12". The number after the R is a refrigerant class number developed by DuPont to systematically identify single halogenated hydrocarbons, as well as other refrigerants besides halocarbons. Most uses of CFCs are now banned ... | https://en.wikipedia.org/wiki?curid=232280 |
Butyric acid (from , meaning "butter"), also known under the systematic name butanoic acid is a carboxylic acid with the structural formula CHCHCHCOH. Classified as a carboxylic acid, it is an oily, colorless liquid that is soluble in water, ethanol, and ether. Isobutyric acid (2-methylpropanoic acid) is an isomer. Sal... | https://en.wikipedia.org/wiki?curid=232345 |
Butyric acid is prepared industrially by oxidation of butyraldehyde. It can be separated from aqueous solutions by saturation with salts such as calcium chloride. The calcium salt, Ca(CHO)·HO, is less soluble in hot water than in cold. was first observed in impure form in 1814 by the French chemist Michel Eugène Chevre... | https://en.wikipedia.org/wiki?curid=232345 |
Butyric acid Low-molecular-weight esters of butyric acid, such as methyl butyrate, have mostly pleasant aromas or tastes. As a consequence, they are used as food and perfume additives. It is an approved food flavoring in the EU FLAVIS database (number 08.005). Due to its powerful odor, it has also been used as a fishin... | https://en.wikipedia.org/wiki?curid=232345 |
Butyric acid The balanced equation for this fermentation is Other pathways to butyrate include succinate reduction and crotonate disproportionation. Several species form acetone and "n"-butanol in an alternative pathway, which starts as butyrate fermentation. Some of these species are: These bacteria begin with butyrat... | https://en.wikipedia.org/wiki?curid=232345 |
Butyric acid Sources of fructans include wheat (although some wheat strains such as spelt contain lower amounts), rye, barley, onion, garlic, Jerusalem and globe artichoke, asparagus, beetroot, chicory, dandelion leaves, leek, radicchio, the white part of spring onion, broccoli, brussels sprouts, cabbage, fennel and pr... | https://en.wikipedia.org/wiki?curid=232345 |
Butyric acid Therefore, butyric acid is thought to enhance the transcriptional activity at promoters, which are typically silenced or downregulated due to histone deacetylase activity. Butyrate that is produced in the colon through microbial fermentation of dietary fiber is primarily absorbed and metabolized by colonoc... | https://en.wikipedia.org/wiki?curid=232345 |
Butyric acid In humans, the butyrate prodrug tributyrin is metabolized by triacylglycerol lipase into dibutyrin and butyrate through the reaction: Butyrate has numerous effects on energy homeostasis and related diseases (diabetes and obesity), inflammation, and immune function (e.g., it has pronounced antimicrobial and... | https://en.wikipedia.org/wiki?curid=232345 |
Butyric acid In vitro, butyrate increases gene expression of FOXP3 (the transcription regulator for ) and promotes colonic regulatory T cells (Tregs) through the inhibition of class I histone deacetylases; through these actions, it increases the expression of interleukin 10, an anti-inflammatory cytokine. Butyrate also... | https://en.wikipedia.org/wiki?curid=232345 |
Butyric acid In particular, butyrate inhibits colonic tumor cells and stimulates proliferation of healthy colonic epithelial cells. The signaling mechanism is not well understood. The production of volatile fatty acids such as butyrate from fermentable fibers may contribute to the role of dietary fiber in colon cancer.... | https://en.wikipedia.org/wiki?curid=232345 |
Putrefaction is the fifth stage of death, following pallor mortis, algor mortis, rigor mortis, and livor mortis. This process references the breaking down of a body of an animal such as a human post-mortem (meaning after death). In broad terms, it can be viewed as the decomposition of proteins, and the eventual breakdo... | https://en.wikipedia.org/wiki?curid=232412 |
Putrefaction Body farms are facilities which study the process of human decomposition as well as how environmental factors affect the rate of putrefaction. In thermodynamic terms, all organic tissues are composed of chemical energy, which, when not maintained by the constant biochemical maintenance of the living organi... | https://en.wikipedia.org/wiki?curid=232412 |
Putrefaction In the course of putrefaction, the skin tissues of the body eventually rupture and release the bacterial gas. As the anaerobic bacteria continue consuming, digesting, and excreting the tissue proteins, the body's decomposition progresses to the stage of skeletonization. This continued consumption also resu... | https://en.wikipedia.org/wiki?curid=232412 |
Putrefaction The first external sign of putrefaction in a body lying in air is usually a greenish discoloration of the skin over the region of the caecum, which appears in 12–24 hours. The first internal sign is usually a greenish discoloration on the undersurface of liver. Various factors affect the rate of putrefacti... | https://en.wikipedia.org/wiki?curid=232412 |
Putrefaction The composition of graves can also be a significant contributing factor, with dense, clay-like soil tending to speed putrefaction while dry and sandy soil slows it. Light exposure: Light can also contribute indirectly, as flies and insects prefer to lay eggs in areas of the body not exposed to light, such ... | https://en.wikipedia.org/wiki?curid=232412 |
Putrefaction The most common reasons to briefly preserve the body are for viewing purposes at a funeral and for medical or religious practices. Body farms subject donated cadavers to various environmental conditions to study the process of human decomposition. These include The University of Tennessee's Forensic Anthro... | https://en.wikipedia.org/wiki?curid=232412 |
Putrefaction In alchemy, putrefaction is the same as fermentation, whereby a substance is allowed to rot or decompose undisturbed. In some cases, the commencement of the process is facilitated with a small sample of the desired material to act as a "seed", a technique akin to the use of a seed crystal in crystallizatio... | https://en.wikipedia.org/wiki?curid=232412 |
Spliceosome A spliceosome is a large and complex molecular machine found primarily within the nucleus of eukaryotic cells. The spliceosome is assembled from small nuclear RNAs (snRNA) and approximately 80 proteins. The spliceosome removes introns from a transcribed pre-mRNA, a type of primary transcript. This process i... | https://en.wikipedia.org/wiki?curid=232937 |
Spliceosome Roberts were awarded the 1993 Nobel Prize in Physiology or Medicine for the discovery of introns and the splicing process. Each spliceosome is composed of five small nuclear RNAs (snRNA) and a range of associated protein factors. When these small RNAs are combined with the protein factors, they make RNA-pro... | https://en.wikipedia.org/wiki?curid=232937 |
Spliceosome Many proteins exhibit a zinc-binding motif, which underscores the importance of zinc in the splicing mechanism. The first molecular-resolution reconstruction of U4/U6.U5 triple small nuclear ribonucleoprotein (tri-snRNP) complex was reported in 2016. Cryo-EM has been applied extensively by Shi et al to eluc... | https://en.wikipedia.org/wiki?curid=232937 |
Spliceosome The model for formation of the spliceosome active site involves an ordered, stepwise assembly of discrete snRNP particles on the pre-mRNA substrate. The first recognition of pre-mRNAs involves U1 snRNP binding to the 5' end splice site of the pre-mRNA and other non-snRNP associated factors to form the commi... | https://en.wikipedia.org/wiki?curid=232937 |
Spliceosome It is unclear how the tri-snRNP is recruited to complex A, but this process may be mediated through protein-protein interactions and/or base pairing interactions between U2 snRNA and U6 snRNA. The U5 snRNP interacts with sequences at the 5' and 3' splice sites via the invariant loop of U5 snRNA and U5 prote... | https://en.wikipedia.org/wiki?curid=232937 |
Spliceosome For example, in the active form, stem loop IIa is favored; in the inactive form a mutually exclusive interaction between the loop and a downstream sequence predominates. It is unclear how U4 is displaced from U6 snRNA, although RNA has been implicated in spliceosome assembly, and may function to unwind U4/U... | https://en.wikipedia.org/wiki?curid=232937 |
Polyvinyl acetate (PVA, PVAc, poly(ethenyl ethanoate): best known as wood glue, white glue, carpenter's glue, school glue, Elmer's glue in the US, or PVA glue) is an aliphatic rubbery synthetic polymer with the formula (CHO). It belongs to the polyvinyl ester family, with the general formula -[RCOOCHCH]-. It is a type ... | https://en.wikipedia.org/wiki?curid=233089 |
Polyvinyl acetate is prepared by the polymerization of vinyl acetate monomer (free radical vinyl polymerization of the monomer vinyl acetate). As an emulsion in water, PVAc emulsions are used as adhesives for porous materials, particularly for wood, paper, and cloth, and as a consolidant for porous building stone, in p... | https://en.wikipedia.org/wiki?curid=233089 |
Air compressor An air compressor is a device that converts power (using an electric motor, diesel or gasoline engine, etc.) into potential energy stored in pressurized air (i.e., compressed air). By one of several methods, an air compressor forces more and more air into a storage tank, increasing the pressure. When the... | https://en.wikipedia.org/wiki?curid=233195 |
Air compressor In these types, a rotating component imparts its kinetic energy to the air which is eventually converted into pressure energy. These use centrifugal force generated by a spinning impeller to accelerate and then decelerate captured air, which pressurizes it. Due to adiabatic heating, air compressors requi... | https://en.wikipedia.org/wiki?curid=233195 |
Air compressor Most air compressors either are reciprocating piston type, rotary vane or rotary screw. Centrifugal compressors are common in very large applications, while rotary screw, scroll, and reciprocating air compressors are favored for smaller, portable applications. There are two main types of air-compressor p... | https://en.wikipedia.org/wiki?curid=233195 |
Air compressor To ensure all compressor types run efficiently with no leaks, it is imperative to perform routine maintenance, such as monitoring and replacing air compressor fittings. It is suggested that air compressor owners perform daily inspections of their equipment, such as: | https://en.wikipedia.org/wiki?curid=233195 |
Martensite is a very hard form of steel crystalline structure. It is named after the German Adolf Martens (1850–1914). By analogy the term can also refer to any crystal structure that is formed by diffusionless transformation. is formed in carbon steels by the rapid cooling (quenching) of the austenite form of iron at ... | https://en.wikipedia.org/wiki?curid=233266 |
Martensite 6% C steel, to 13% retained austenite at 0.95% C and 30–47% retained austenite for a 1.4% carbon steels. A very rapid quench is essential to create martensite. For a eutectoid carbon steel of thin section, if the quench starting at 750 °C and ending at 450 °C takes place in 0.7 seconds (a rate of 430 °C/s) n... | https://en.wikipedia.org/wiki?curid=233266 |
Martensite The great number of dislocations, combined with precipitates that originate and pin the dislocations in place, produces a very hard steel. This property is frequently used in toughened ceramics like yttria-stabilized zirconia and in special steels like TRIP steels. Thus, martensite can be thermally induced o... | https://en.wikipedia.org/wiki?curid=233266 |
Martensite In some alloys, the effect is reduced by adding elements such as tungsten that interfere with cementite nucleation, but, more often than not, the nucleation is allowed to proceed to relieve stresses. Since quenching can be difficult to control, many steels are quenched to produce an overabundance of martensi... | https://en.wikipedia.org/wiki?curid=233266 |
Cementite (or iron carbide) is a compound of iron and carbon, more precisely an intermediate transition metal carbide with the formula FeC. By weight, it is 6.67% carbon and 93.3% iron. It has an orthorhombic crystal structure. It is a hard, brittle material, normally classified as a ceramic in its pure form, and is a ... | https://en.wikipedia.org/wiki?curid=233281 |
Cementite While cementite is thermodynamically unstable, eventually being converted to austenite (low carbon level) and graphite (high carbon level) at higher temperatures, it does not decompose on heating at temperatures below the eutectoid temperature (723 °C) on the metastable iron-carbon phase diagram. changes from... | https://en.wikipedia.org/wiki?curid=233281 |
Cementite It has also been found naturally as the mineral Edscottite in the Wedderburn meteorite Characterization of different iron carbides is not at all a trivial task, and often X-ray diffraction is complemented by Mössbauer spectroscopy. | https://en.wikipedia.org/wiki?curid=233281 |
Austenite Austenite, also known as gamma-phase iron (γ-Fe), is a metallic, non-magnetic allotrope of iron or a solid solution of iron, with an alloying element. In plain-carbon steel, austenite exists above the critical eutectoid temperature of 1000 K (727 °C); other alloys of steel have different eutectoid temperature... | https://en.wikipedia.org/wiki?curid=233317 |
Austenite The metal is heated into the austenite region of the iron-cementite phase diagram and then quenched in a salt bath or other heat extraction medium that is between temperatures of . The metal is annealed in this temperature range until the austenite turns to bainite or ausferrite (bainitic ferrite + high-carbo... | https://en.wikipedia.org/wiki?curid=233317 |
Austenite The rate of cooling determines the relative proportions of martensite, ferrite, and cementite, and therefore determines the mechanical properties of the resulting steel, such as hardness and tensile strength. A high cooling rate of thick sections will cause a steep thermal gradient in the material. The outer ... | https://en.wikipedia.org/wiki?curid=233317 |
Austenite This austenisation of white iron occurs in primary cementite at the interphase boundary with ferrite. When the grains of austenite form in cementite, they occur as lamellar clusters oriented along the cementite crystal layer surface. is formed by diffusion of carbon atoms from cementite into ferrite. The addi... | https://en.wikipedia.org/wiki?curid=233317 |
Austenite This behavior is attributed to the paramagnetic nature of austenite, while both martensite and ferrite are strongly ferromagnetic. During heat treating, a blacksmith causes phase changes in the iron-carbon system in order to control the material's mechanical properties, often using the annealing, quenching, a... | https://en.wikipedia.org/wiki?curid=233317 |
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