The gene they picked was for cytochrome P450 13E1, a mammalian enzyme that oxidises a wide range of volatile organic compounds, including benzene, chloroform, trichloroethylene and carbon tetrachloride.
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There, it oxidises the cysteine groups of redox-sensitive proteins, which can then transduce signals.
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In basic conditions sulfite easily oxidises to sulfate and in acidic conditions it easily turns into sulfur dioxide.
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In the presence of mineral acids, and used warm or boiling, chromic acid oxidises cellulose into oxycellulose and other products.
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The working temperature is 70ºC. The process takes place basically because the sodium perborate oxidises the stagnate ion into stannic.
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Bosea thiooxidans is a gram-negative species of bacteria that oxidises thiosulfate, the type species of its genus. Its type strain is BI-42.
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Because commercial acetylene gas contains some phosphine, an oxy-acetylene flame will have weak PO emission bands in its spectrum also. In the flame, PO oxidises back to P4O10.
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When heated in air or oxygen at over 500 °C, bastnäsite oxidises and loses volatiles to form ceria (CeO2). Lukechangite also oxidises to ceria and sodium fluoride (NaF). Ce7O12 results when heated to over 1000 °C. : 2 Ce(CO3F) + O2 → 2 CeO2 \+ 2 CO2 \+ F2 : Na3Ce2(CO3F)4F + O2 → 2 CeO2 \+ 3 CO2 \+ NaF + Na2CO3 At 1300 °C Na2CO3 loses CO2, and between 1300 and 1600 °C NaF and Na2O boil off.
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Concentrated nitric acid only oxidises iodine to iodic acid and doesn't affect any other halogens. Even the oxidation of iodine by concentrated nitric acid happens only at high temperatures. This test was invented by the German Chemist, Georg Ludwig Carius (1829-1875).
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S. acidocaldarius is a facultative autotroph. When growing autotrophically this organism oxidises sulfur to sulfate, while fixating carbon from carbon dioxide. The doubling time of cultures growing on sulfur alone falls between 36.8-55.3h. This species can also grow on complex organic substrates.
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The repeated, saturated exposure to air oxidises the skin and flesh of the fruit, turning it black in an artificial process that mimics natural ripening. Once fully oxidised or "blackened", they are brined and acid corrected and are then ready for eating.
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Commercially available glucose monitors rely on amperometric sensing of glucose by means of glucose oxidase, which oxidises glucose producing hydrogen peroxide which is detected by the electrode. To overcome the limitation of amperometric sensors, a flurry of research is present into novel sensing methods, such as fluorescent glucose biosensors.
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Sulfurovum lithotrophicum is a species of bacteria, the type species of its genus. It is a sulfur-oxidizing chemolithoautotroph within the ε-Proteobacteria isolated from Okinawa Trough hydrothermal sediments. It is mesophilic and also oxidises thiosulfate. It is a Gram-negative, non-motile and coccoid to oval-shaped bacterium.
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It is quite volatile and decomposes at 32 °C. Its infrared spectrum shows a band at 2028 cm−1 due to CCCO. The complex can dissolve in hexane, however it slowly decomposes, losing dicarbon (C2) which goes on to form acetylenes and cumulenes in the solvent. Dimethyl sulfoxide oxidises the CCCO ligand to carbon suboxide.
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As white phosphorus oxidises it gives out a greenish-white glow. The glow happens as PO is oxidised by one of these reactions: PO + O• → PO2; or PO + O2 →PO2 \+ O•. The possible ways that PO appears in this process is by breakup of the P2O molecule which in turn may come from P4O.
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This can be done by conducting the reaction in the presence of an oxidising agent that oxidises HI to I2, thus removing HI from the reaction and generating more iodine that can further react. The reaction steps involved in iodination are the following: 400x400px Another method to obtain aromatic iodides is the Sandmeyer reaction.
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It can be made by oxidising nickel nitrate in a cold alkaline solution with bromine. A mixed oxidation state hydroxide Ni3O2(OH)4 is made if oxidation happens in a hot alkaline solution. A Ni4+ hydroxide: nickel peroxide hydrate NiO2, can be made by oxidising with alkaline peroxide. It is black, and unstable and oxidises water.
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Thorium is less radioactive than uranium. Thorium fuels result in a safer and better-performing reactor core because thorium dioxide has a higher melting point, higher thermal conductivity, and a lower coefficient of thermal expansion. It is more stable chemically than the now-common fuel uranium dioxide, because the latter oxidises to triuranium octoxide (U3O8), becoming substantially less dense.
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Nickel nitrite decomposes when heated to 220°C, however it can be heated up to 260°C in argon. The nitrite is covalently bonded to nickel, and the material is slightly volatile. The infrared spectrum of the solid has absorption bands at 1575, 1388, 1333, 1240, 1080, and 830 cm−1. Liquid dinitrogen tetroxide oxidises nickel nitrite to nickel nitrate.
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In rats, TAA is primarily metabolized via glucuronidation, as well as by oxidation to 2-methyl-2,3-butanediol. It is likely that the same path is followed in humans, though older sources suggest TAA is excreted unchanged. TAA oxidises to 2-methyl-2,3-butanediol. The use of TAA cannot be detected with general ethanol tests or other ordinary drug tests.
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The preserve is normally applied to soil when ready, or can be stored unopened for later use. # The preserve is mixed into soil. This exposes it to air, whereupon the lactic acid oxidises to pyruvate, a fundamental energy carrier in biological processes. # The oxidised preserve is soon consumed by the indigenous soil life, ‘disappearing’ within a very few weeks at normal temperatures.
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Using the radioactive isotope 103Ru produces a ruthenocenyl–haloperidol radiopharmaceutical with a high affinity for lung but not brain tissue in mice and rats. Beta-decay of 103Ru produces the metastable isotope 103mRh in a rhodocenyl–haloperidol compound. This compound, like other rhodocene derivatives, has an unstable 19-valence electron configuration and rapidly oxidises to the expected cationic rhodocenium–haloperidol species.
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Peroxynitrite may also react with various amino acids in the peptide chain, thereby altering protein structure and subsequently, protein function. It most commonly oxidises cysteine, and may indirectly induce tyrosine nitration through other generated RNS. Altered protein function includes changes in enzyme catalytic activity, cytoskeletal organisation and cell signal transduction. Hypochlorous acid reacts with a range of biomolecules, including DNA, lipids and proteins.
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However, obtaining this level of purity was not economical for submarine cables. Impure gutta-percha oxidises and becomes brittle. The rate of deterioration is very slow for cable permanently in the water, but cable crossing the landing zone is exposed to frequent changes in temperature and cycles of exposure and submerging. This environment could cause the insulation to crumble and expose the conductor.
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8–9 It is a very porous stone and acts as a giant filter. It is composed of very pure silica grains and a small amount of the iron mineral siderite in varying proportions, bound with a clay matrix.Flannery, Tim; 'The Stone', in Deirmendjian, 2002. It oxidises to the warm yellow-brown colour that is notable in the buildings which are constructed of it.
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Bismuth pentafluoride is the most reactive of the pnictogen pentafluorides and is an extremely strong fluorinating agent. It reacts vigorously with water to form ozone and oxygen difluoride, and with iodine or sulfur at room temperature. BiF5 fluorinates paraffin oil (hydrocarbons) to fluorocarbons above 50 °C and oxidises UF4 to UF6 at 150 °C. At 180 °C, bismuth pentafluoride fluorinates Br2 to BrF3 and Cl2 to ClF.
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Polymer Al-e-caps exhibit the same self- healing mechanism as polymer Ta-e-caps. After application of a voltage at weakened spots in the oxide, a localised higher leakage current path is formed. This leads to a local heating of the polymer; whereby the polymer either oxidises and becomes highly resistive - or evaporates. Also, hybrid polymer Al-e-caps show this self-healing mechanism.
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MoTe2 gradually oxidises in air forming molybdenum dioxide (MoO2). At elevated temperatures MoTe2 oxidation produces Te2MoO7 and TeMo5O16. Other oxidation products include molybdenum trioxide, tellurium, and tellurium dioxide. Flakes of molybdenum ditelluride that contain many defects have lower luminescence, and absorb oxygen from the air, losing their luminescence. When heated to high temperatures, tellurium evaporates from molybdenum ditelluride, producing the tellurium deficient forms and then Mo2Te3.
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An unexpected entry into the Thanet Sand while excavating near Tooting Bec Common led to the flooding of the tunnel and the temporary abandonment of a Tunnel Boring Machine (TBM). A further consideration of Thanet Sand is the presence of glauconite, which oxidises on contact with air. The resulting de-oxygenated air resulted in two fatalities during the excavation of a pump-out shaft.
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To separate the silver, the alloy is melted again at the high temperature of 960°C to 1000°C in an oxidizing environment. The lead oxidises to lead monoxide, then known as litharge, which captures the oxygen from the other metals present. The liquid lead oxide is removed or absorbed by capillary action into the hearth linings. This chemical reactionCraddock, P. T. 1995:223Bayley, J., Crossley, D. and Ponting, M. (eds).
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The amount of glass allowed to pour onto the molten tin is controlled by a gate called a tweel. Tin is suitable for the float glass process because it has a high specific gravity, is cohesive, and is immiscible with molten glass. Tin, however, oxidises in a natural atmosphere to form tin dioxide (SnO2). Known in the production process as dross, the tin dioxide adheres to the glass.
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The facility extracts the methane gas produced by the decomposition of organic matter in the landfill and oxidises the methane via the engine to utilise the energy to produce electricity. Three kilometres of gas pipe has been installed across the landfill site connecting the existing 55 wells to the generator. Up to 20 additional wells may be inserted over the next five years. The wells are up to 15 metres deep.
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Carnitine synthesis To ensure a continuous guarantee of energy supply, the body oxidises considerable amounts of fat along with glucose. Carnitine transports activate long-chain fatty acids (FA) from the cytosol of the cell into the mitochondrion and is therefore essential for fatty acid oxidation (known as beta oxidation). Carnitine is mainly absorbed from the diet, but can be formed through biosynthesis. To produce carnitine, lysine residues are methylated to trimethyllysine.
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The ground water contains high levels of iron which oxidises and causes acidity levels to rise. In 2009, the government called for submissions for an Environmental Impact Assessment relating to the effects of reconnecting Collie River South to the lake, which is intended to create a flushing effect. The river is upstream from Wellington Dam and was diverted around the southern edge of the site throughout the mining operations.
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It oxidises readily in air to form arsenic trioxide and water, and analogous reactions take place with sulfur and selenium instead of oxygen. Arsenic forms colorless, odorless, crystalline oxides As2O3 ("white arsenic") and As2O5 which are hygroscopic and readily soluble in water to form acidic solutions. Arsenic(V) acid is a weak acid and the salts are called arsenates, the most common arsenic contamination of groundwater, and a problem that affects many people.
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Knox et al. first noted that HClO is a sulfhydryl inhibitor that, in sufficient quantity, could completely inactivate proteins containing sulfhydryl groups. This is because HClO oxidises sulfhydryl groups, leading to the formation of disulfide bonds that can result in crosslinking of proteins. The HClO mechanism of sulfhydryl oxidation is similar to that of monochloramine, and may only be bacteriostatic, because once the residual chlorine is dissipated, some sulfhydryl function can be restored.
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Swern oxidation oxidises secondary alcohols into ketones using oxalyl chloride and dimethylsulfoxide. It also requires an organic base, such as triethylamine. center The by-products are dimethyl sulfide (Me2S), carbon monoxide (CO), carbon dioxide (CO2) and – when triethylamine is used as base – triethylammonium chloride (C6H15NHCl). Dimethyl sulfide and carbon monoxide are very toxic and malodorous compounds, so the reaction and the work-up needs to be performed in a fume hood or outdoors.
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It is an isomer of nitric acid and isomerises with a rate constant of k = 1.2 s−1, a process whereby up to 5% of hydroxyl and nitrogen dioxide radicals may be formed. It oxidises and nitrates aromatic compounds in low yield. The mechanism may involve a complex between the aromatic compound and ONOOH, and a transition from the cis- to the trans- configuration of ONOOH. Peroxynitrous acid is also important in atmospheric chemistry.
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The pH of an alkaline soil can be reduced by adding acidifying agents or acidic organic materials. Elemental sulfur (90–99% S) has been used at application rates of 300–500 kg/ha – it slowly oxidizes in soil to form sulfuric acid. Acidifying fertilizers, such as ammonium sulfate, ammonium nitrate and urea, can help to reduce the pH of a soil because ammonium oxidises to form nitric acid. Acidifying organic materials include peat or sphagnum peat moss.
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Manganese(II) hydroxide precipitates as a solid when an alkali metal hydroxide is added to an aqueous solution of Mn2+ salt:H. Lux "Manganese(IV) Hydroxide" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 1456. :Mn2+ \+ 2 NaOH → Mn(OH)2 \+ 2 Na+ Manganese(II) hydroxide oxidises readily in air, as indicated by darkening of samples. The compound adopts the brucite structure, as do several other metal dihydroxides.
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As the saltpetre decomposes, it oxidises the sulphur to sulfur trioxide, which combines with water to produce sulphuric acid. This was the first practical production of sulphuric acid on a large scale.Sulphur surplus: Up to our necks in a diabolical element, BBC, 18 July 2014 Ward was in many ways quite generous to those living in poverty. He opened hospitals for the poor in Westminster as well as in the City of London and the clinics did not charge people for their service.
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Scale is a problem because it insulates and heat exchange becomes less efficient as the scale thickens, which wastes energy. Scale also narrows pipe widths and therefore increases the energy used in pumping the water through the pipes. Corrosion occurs when the parent metal oxidises (as iron rusts, for example) and gradually the integrity of the plant equipment is compromised. The corrosion products can cause similar problems to scale, but corrosion can also lead to leaks, which in a pressurised system can lead to catastrophic failures.
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On the morning of Friday 11 October, when the fire was at its worst, eleven tons of uranium were ablaze. Temperatures were becoming extreme (one thermocouple registered 1,300 °C) and the biological shield around the stricken reactor was now in severe danger of collapse. Faced with this crisis, Tuohy suggested using water. This was risky, as molten metal oxidises in contact with water, stripping oxygen from the water molecules and leaving free hydrogen, which could mix with incoming air and explode, tearing open the weakened containment.
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A more biotechnological process, first developed in China in the 1960s, but further developed in the 1990s, bypasses the use of acetone-protecting groups. A second genetically modified microbe species, such as mutant Erwinia, among others, oxidises sorbose into 2-ketogluconic acid (2-KGA), which can then undergo ring-closing lactonization via dehydration. This method is used in the predominant process used by the ascorbic acid industry in China, which supplies 80% of world's ascorbic acid.China's grip on key food additive / The Christian Science Monitor. CSMonitor.
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Acetobacterium carbinolicum is a homoacetogenic, strictly anaerobic bacterium that oxidises primary aliphatic alcohols. These Gram-positive, non-spore- forming and rod-shaped bacteria grow at optimal temperatures of about 30°C, but some subspecies are also psychrotolerant, being able to grow at a minimum temperature of 2°C, as the microorganisms belonging to the subspecies A. carbinolicum kysingense, which have been isolated from fine sand and mud sedimented in a brackish fjord in Jutland, Denmark, where concentrations of sodium chloride (NaCl) in water are up to 4.3%.
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AgF2 is a strong fluorinating and oxidising agent. It is formed as an intermediate in the catalysis of gaseous reactions with fluorine by silver. With fluoride ions, it forms complex ions such as , the blue-violet , and . It is used in the fluorination and preparation of organic perfluorocompounds. This type of reaction can occur in three different ways (here Z refers to any element or group attached to carbon, X is a halogen): # CZ3H + 2 AgF2 → CZ3F + HF + 2 AgF # CZ3X + 2AgF2 → CZ3F + X2 \+ 2 AgF # Z2C=CZ2 \+ 2 AgF2 → Z2CFCFZ2 \+ 2 AgF Similar transformations can also be effected using other high valence metallic fluorides such as CoF3, MnF3, CeF4, and PbF4. is also used in the fluorination of aromatic compounds, although selective monofluorinations are more difficult: :C6H6 \+ 2 AgF2 → C6H5F + 2 AgF + HF oxidises xenon to xenon difluoride in anhydrous HF solutions. :2 AgF2 \+ Xe → 2 AgF + XeF2 It also oxidises carbon monoxide to carbonyl fluoride. :2 AgF2 \+ CO → 2 AgF + COF2 It reacts with water to form oxygen gas: :4 AgF2 \+ 4 H2O → 2 Ag2O + 8 HF + O2 can be used to selectively fluorinate pyridine at the ortho position under mild conditions.
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Though proteobacteria display impressive acid tolerance, most retain a circumneutral cytoplasm to avoid denaturation of their acid-labile cell constituents. Archaea such as Ferroplasma acidiphilum, which oxidises ferrous iron, have a number of intracellular enzymes with an optimum similar to that of their external acidic environment. This may explain their ability to survive pH as low as 1.3. The differing cell membranes in archaea compared to the bacteria may hold part of the explanation; ether lipids that link isoprene, compared to proteobacteria's di-ester linkage, are central to the difference.
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The beaches, dunes and sandstone cliffs consist of sedimentary rock and other material with a high iron concentration, which oxidises upon exposure to the air. The geological properties of a white silica sand found at Basin Head are unique in the province; the sand grains cause a scrubbing noise as they rub against each other when walked on, and have been called the "singing sands". Large dune fields on the north shore can be found on barrier islands at the entrances to various bays and harbours. The sand dunes at Greenwich are of particular significance.
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Xenon trioxide is a strong oxidising agent and can oxidise most substances that are at all oxidisable. However, it is slow-acting and this reduces its usefulness. Above 25 °C, xenon trioxide is very prone to violent explosion: :2 XeO3 → 2 Xe + 3 O2 (ΔHf = −402 kJ/mol) When it dissolves in water, an acidic solution of xenic acid is formed: :XeO3(aq) + H2O → H2XeO4 H+ \+ This solution is stable at room temperature and lacks the explosive properties of xenon trioxide. It oxidises carboxylic acids quantitatively to carbon dioxide and water.
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The roof structure is made entirely of laminated wood, a plywood. The entire roof is covered with a copper skin plate, which has been described by the European Association for the Development of Architectural Copper as that "it gradually oxidises to dark brown colour, and then, after several years, the typical green patina of aged copper protects the building and its contents for decades, even in the aggressive marine environment." The first floor, ground floor and basement of the building are . Three wide vaults or rooms extend to the ceiling and are divided by the Mesozoic divisions of Cretaceous, Jurassic, and Triassic.
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Such trapped gases and smoke caused fogs and worse, smogs which discoloured clothing and was a serious health hazard. Such pea soupers were generally more prevalent in the larger towns such as Manchester, Birmingham and London. There were also toxic gases such as sulphur dioxide and nitrogen oxides present in the same noxious mixture, both of which irritated the lungs of those exposed to the smog. The former gas produced by sulphur impurities in the coal, was especially iniquitous since it oxidises further in the air to produce sulphuric acid, a highly corrosive and strong acid.
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2009 It was carried out in small shallow recipients known as cupels. As the main purpose of small scale cupellation was to assay and test minerals and metals, the matter to be tested has to be carefully weighed. The assays were made in the cupellation or assay furnace, which needs to have windows and bellows to ascertain that the air oxidises the lead, as well as to be sure and prepared to take away the cupel when the process is over. Pure lead has to be added to the matter being tested to guarantee the further separation of the impurities.
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The lead melts and oxidises to lead oxide, which in turn melts and is drawn into the pores of the cupel by capillary attraction. The precious metals remain in the base of the cupel as a 'prill' which is sent for final analysis of precious metal content. In the bullion fire assay process, a sample from the article is wrapped in a lead foil with copper and silver. The wrapped sample, along with prepared control samples, heated at 1650 F (temperature varies with exact method) in a cupel made of compressed bone ash or magnesium oxide powder.
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A cask of fino is considered to be amontillado if the layer of flor fails to develop adequately, is intentionally killed by additional fortification, or is allowed to die off through non-replenishment. Without the layer of flor, amontillado must be fortified to approximately 17.5% alcohol so that it does not oxidise too quickly. After the additional fortification, Amontillado oxidises slowly, exposed to oxygen through the slightly porous American or Canadian oak casks, and gains a darker colour and richer flavour than fino. Amontillado is characterized by nutty aromas, tobacco, aromatic herbs and often ethereal, polished notes of oak.
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Balances can only compare the mass of a silicon sphere to that of a reference mass. Given the latest understanding of the lack of long-term mass stability with the IPK and its replicas, there is no known, perfectly stable mass artefact to compare against. Single-pan scales, which measure weight relative to an invariant of nature, are not precise to the necessary long-term uncertainty of 10–20 parts per billion. Another issue to be overcome is that silicon oxidises and forms a thin layer (equivalent to silicon atoms deep) of silicon dioxide (quartz) and silicon monoxide.
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Iodine pentoxide easily oxidises carbon monoxide to carbon dioxide at room temperature: :5 CO + I2O5 → I2 \+ 5 CO2 This reaction can be used to analyse the concentration of CO in a gaseous sample. I2O5 forms iodyl salts, [IO2+], with SO3 and S2O6F2, but iodosyl salts, [IO+], with concentrated sulfuric acid. Iodine pentoxide decomposes to iodine (vapor) and oxygen when heated to about 350 °C.G. Baxter and G. Tilley, "A Revision of the Atomic Weights of Iodine and Silver," The Chemical News and Journal of Industrial Science; Volumes 99-100, Royal Society Anniversary Meeting, December 3, 1909, p. 276.
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After crushing the seeds to extract linseed oil, the resultant linseed meal is a protein-rich feed for ruminants, rabbits, and fish. It is also often used as feed for swine and poultry, and has also been used in horse concentrate and dog food. The high omega-3 fatty acid (ALA) content of linseed meal "softens" milk, eggs or meat, which means it causes a higher unsaturated fat content and thus lowers its storage time. The high omega-3 content also has a further disadvantage, because this fatty acid oxidises and goes rancid quickly, which shortens the storage time.
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The interactions between the different dipoles of each molecule cause a net attraction force. Oxides, such as iron oxide or rust, , form when oxygen combines with other elements Due to its electronegativity, oxygen forms chemical bonds with almost all other free elements at elevated temperatures to give corresponding oxides. However, some elements, such as iron which oxidises to iron oxide, or rust, , readily oxidise at standard conditions for temperature and pressure (STP). The surface of metals like aluminium and titanium are oxidized in the presence of air and become coated with a thin film of oxide that passivates the metal and slows further corrosion.
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Due to the basicity of the Se2− and Te2− ions, the alkali metal selenides and tellurides are alkaline in solution; when reacted directly with selenium and tellurium, alkali metal polyselenides and polytellurides are formed along with the selenides and tellurides with the and ions. They may be obtained directly from the elements in liquid ammonia or when air is not present, and are colourless, water-soluble compounds that air oxidises quickly back to selenium or tellurium. The alkali metal polonides are all ionic compounds containing the Po2− ion; they are very chemically stable and can be produced by direct reaction of the elements at around 300–400 °C.
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The resultant flour material is then transported through a reduction system in which finer particulates are sorted and collected, the coarser particles being reintroduced for further treatment and size reduction. In the final milling process, the flour is treated with a substance that oxidises carotene in the material, thus whitening it. In addition, the treatment process fortifies the flour product with vitamins B1, B2, C, Iron and Niacin and serves as a means of bolstering poor rates of public nutrition. This has been done in response to the phenomena of high rates of iron-deficiency anaemia prevalent in predominately rural and developing economies such as Guyana.
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The process consists of treating zinc containing material, in which zinc can be in the form zinc oxide, zinc silicate, zinc ferrite, zinc sulphide together with a carbon containing reductant/fuel, within a rotary kiln at 1000 °C to 1500 °C. The kiln feed material comprising zinc 'waste', fluxes and reductant (coke) is typically pelletized before addition to the kiln. The chemical process involves the reduction of zinc compounds to elemental zinc (boiling point 907 °C) which volatalises, which oxidises in the vapour phase to zinc oxide. The zinc oxide is collected from the kiln outlet exhaust by filters/electrostatic precipitators/settling chambers etc.
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PSII is a multisubunit protein-pigment complex containing polypeptides bound to the photosynthetic membrane. Within the core of the complex, the chlorophyll and beta-carotene pigments are mainly bound to the antenna proteins CP43 (PsbC) and CP47 (PsbB), which pass the excitation energy on to the reaction centre proteins D1 (Qb, PsbA) and D2 (Qa, PsbD) that bind all the redox-active cofactors involved in the energy conversion process. The PSII oxygen-evolving complex (OEC) oxidises water to provide protons for use by PSI, and consists of OEE1 (PsbO), OEE2 (PsbP) and OEE3 (PsbQ). The remaining subunits in PSII are of low molecular weight (less than 10 kDa), and are involved in PSII assembly, stabilisation, dimerisation, and photo- protection.
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By 1932 the lead concentration had reduced to 0.02ppm to 0.1ppm because of the abandonment of mining and, at those concentrations, the bottom fauna had stabilized to 103 species including three leeches.Laurie, R.D. and Jones, J.R.E., 1938, The faunistic recovery of a lead polluted river in north Cardiganshire, Wales, J. Anim. Ecol, 7, 272 -286 Coal mining is also a very significant source of metals, especially Iron, Zinc and Nickel particularly where the coal is rich if pyrites which oxidises on contact with the air producing a very acidic leachate which is able to dissolve metals from the coal. Significant levels of copper are unusual in rivers and where it does it occur the source is most likely to be mining activities, coal stocking, or pig farming.
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This is because the monoclinic angle c changes to 90°. This form is called β' or, misleadingly, Td. The transition from α- to β-MoTe2 happens at 820 °C, but if Te is reduced by 5% the required transition temperature increases to 880 °C. K. Ueno and K. Fukushima claim that when the α form is heated in a low or high vacuum that it oxidises to form MoO2 and that reversible phase transitions do not take place. In bulk, MoTe2 can be produced as a single crystal with difficulty, but can also be made as a powder, as a polycrystalline form, as a thin film, as a nanolayer consisting of a few TeMoTe sheets, a bilayer consisting of two sheets or as a monolayer with one sheet.
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Hypophosphoric acid can be prepared by the reaction of red phosphorus with sodium chlorite at room temperature.Phosphorus: Chemistry, Biochemistry and Technology, Sixth Edition, 2013, D.E.C. Corbridge, CRC Pres, Taylor Francis Group, :2 P + 2 NaClO2 \+ 2 H2O → Na2H2P2O6 \+ 2 HCl A mixture of hypophosphoric acid, phosphorous acid (H3PO3) and phosphoric acid (H3PO4) is produced when white phosphorus oxidises in air when partially immersed in water. The tetrasodium salt Na4P2O6·10H2O crystallises at pH 10 and the disodium salt, Na2H2PO6·6H2O at pH 5.2. The disodium salt can be passed through an ion exchange column to form the acid dihydrate, H4P2O6·2H2O. The anhydrous acid can be formed by vacuum dehydration over P4O10 or by the reaction of H2S on lead hypophosphate, Pb2P2O6. Hypophosphoric acid is tetraprotic with dissociation constants pKa1 = 2.2, pKa2 = 2.8, pKa3 = 7.3 and pKa4 = 10.0.
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Furthermore, the mass prototypes produced by ion deposition techniques would have been nothing like the freestanding platinum- iridium prototypes currently in use; they would have been deposited onto—and become part of—an electrode imbedded into one pan of a special balance integrated into the device. Moreover, the ion-deposited mass wouldn't have had a hard, highly polished surface that can be vigorously cleaned like those of current prototypes. Gold, while dense and a noble metal (resistant to oxidation and the formation of other compounds), is extremely soft so an internal gold prototype would have to be kept well isolated and scrupulously clean to avoid contamination and the potential of wear from having to remove the contamination. Bismuth, which is an inexpensive metal used in low- temperature solders, slowly oxidises when exposed to room-temperature air and forms other chemical compounds and so would not have produced stable reference masses unless it was continually maintained in a vacuum or inert atmosphere.
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Each reaction can be applied individually or sequentially as dictated by the characteristics of the stream to be treated. The process consist of three main sections: An absorber (gas washing section), a bioreactor (sulfide oxidation and regeneration of washing liquid) and Sulfur handling section as shown in the figure below: The washing step uses a dilute alkaline solution to remove hydrogen sulfide (H2S) from the sour gas according to: :H2S + NaOH → NaHS + H2O The loaded washing liquid is transported to a bioreactor where a biocatalyst oxidises the aqueous NaHS to elemental sulfur with about 95% selectivity according to: :NaHS + ½ O2 → S + NaOH Combined reaction equation: :H2S + ½ O2 → S + H2O The regenerated washing liquid is sent back to the washing column. The controlled partial oxidation of sulfide to elemental sulfur (2) is catalyzed by naturally occurring microorganisms of the genus Halothiobacillus in the bioreactor. These natural, living microorganisms present in the bioreactor catalyse the sulfur conversions and are, by their nature, resilient and adaptive.
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Functional groups containing heteroatoms in low oxidation states can be oxidised by trifluoroperacetic acid. Common cases include the oxidation of iodine (for example, the formation of the hypervalent iodine compound from iodobenzene mentioned earlier), nitrogen, sulfur, and selenium. In the case of nitrogen-containing compounds, known transformations include oximes and aromatic primary amines to nitro compounds (even with electron-withdrawing substituents, for example, pentafluoroaniline to pentafluoronitrobenzene), nitrosamines to nitramines, formation of aromatic N-oxides and aromatic azine N-oxides, and conversion of nitroso compounds to nitro compounds or nitramines. For example, a mixture of hydrogen peroxide and trifluoroperacetic acid oxidises the nitroso-substituted pyrimidine 4,6-diamino-5-nitrosopyrimidine-2-thiol to its nitro analogue while also removing the thiol moiety by oxidative hydrolytic desulfurization: 500px In the case of chalcogen elements, sulfide moieties (R–S–R) can be oxidised by trifluoroperacetic acid to sulfoxide (R–S(O)–R) and/or sulfone (R–S(O)2–R) forms, depending on the conditions used.
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