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oxo-compounds of chlorine, in keeping with the fact that chlorine compounds are most stable when the chlorine atom is in its lowest (−1) or highest (+7) possible oxidation states. Perchloric acid and aqueous perchlorates are vigorous and sometimes violent oxidising agents when heated, in stark contrast to their mostly ...	{ "page_id": 5667, "title": "Chlorine" }
the difference of electronegativity between chlorine (3.16) and carbon (2.55), the carbon in a C–Cl bond is electron-deficient and thus electrophilic. Chlorination modifies the physical properties of hydrocarbons in several ways: chlorocarbons are typically denser than water due to the higher atomic weight of chlorine ...	{ "page_id": 5667, "title": "Chlorine" }
from marine algae. A majority of the chloromethane in the environment is produced naturally by biological decomposition, forest fires, and volcanoes. Some types of organochlorides, though not all, have significant toxicity to plants or animals, including humans. Dioxins, produced when organic matter is burned in the pr...	{ "page_id": 5667, "title": "Chlorine" }
hydrogen gas and sodium hydroxide, which is the most valuable product. The process proceeds according to the following chemical equation: 2 NaCl + 2 H2O → Cl2 + H2 + 2 NaOH == Production == Chlorine is primarily produced by the chloralkali process, although non-chloralkali processes exist. Global 2022 production was es...	{ "page_id": 5667, "title": "Chlorine" }
cathode and an anode, preventing the chlorine forming at the anode from re-mixing with the sodium hydroxide and the hydrogen formed at the cathode. The salt solution (brine) is continuously fed to the anode compartment and flows through the diaphragm to the cathode compartment, where the caustic alkali is produced and ...	{ "page_id": 5667, "title": "Chlorine" }
are the precursors for producing the pure form of those elements. Quantitatively, of all elemental chlorine produced, about 63% is used in the manufacture of organic compounds, and 18% in the manufacture of inorganic chlorine compounds. About 15,000 chlorine compounds are used commercially. The remaining 19% of chlorin...	{ "page_id": 5667, "title": "Chlorine" }
they were beneficial during exhumations, embalming, outbreaks of epidemic disease, fever, and blackleg in cattle. ==== Disinfection ==== Labarraque's chlorinated lime and soda solutions have been advocated since 1828 to prevent infection (called "contagious infection", presumed to be transmitted by "miasmas"), and to t...	{ "page_id": 5667, "title": "Chlorine" }
famous application of Labarraque's chlorine and chemical base solutions was in 1847, when Ignaz Semmelweis used chlorine-water (chlorine dissolved in pure water, which was cheaper than chlorinated lime solutions) to disinfect the hands of Austrian doctors, which Semmelweis noticed still carried the stench of decomposit...	{ "page_id": 5667, "title": "Chlorine" }
important chemical for water purification (such as in water treatment plants), in disinfectants, and in bleach. Even small water supplies are now routinely chlorinated. Chlorine is usually used (in the form of hypochlorous acid) to kill bacteria and other microbes in drinking water supplies and public swimming pools. I...	{ "page_id": 5667, "title": "Chlorine" }
a weapon === ==== World War I ==== Chlorine gas, also known as bertholite, was first used as a weapon in World War I by Germany on April 22, 1915, in the Second Battle of Ypres. As described by the soldiers, it had the distinctive smell of a mixture of pepper and pineapple. It also tasted metallic and stung the back of...	{ "page_id": 5667, "title": "Chlorine" }
that the Islamic State of Iraq and the Levant had used chlorine gas in the town of Duluiyah, Iraq. Laboratory analysis of clothing and soil samples confirmed the use of chlorine gas against Kurdish Peshmerga Forces in a vehicle-borne improvised explosive device attack on 23 January 2015 at the Highway 47 Kiske Junction...	{ "page_id": 5667, "title": "Chlorine" }
is detectable with measuring devices in concentrations as low as 0.2 parts per million (ppm), and by smell at 3 ppm. Coughing and vomiting may occur at 30 ppm and lung damage at 60 ppm. About 1000 ppm can be fatal after a few deep breaths of the gas. The IDLH (immediately dangerous to life and health) concentration is ...	{ "page_id": 5667, "title": "Chlorine" }
caused widespread failures in the US in the 1980s and 1990s. === Chlorine-iron fire === The element iron can combine with chlorine at high temperatures in a strong exothermic reaction, creating a chlorine-iron fire. Chlorine-iron fires are a risk in chemical process plants, where much of the pipework that carries chlor...	{ "page_id": 5667, "title": "Chlorine" }
Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant ele...	{ "page_id": 5668, "title": "Calcium" }
cell membranes, protein synthesis, and bone formation. == Characteristics == === Classification === Calcium is a very ductile silvery metal (sometimes described as pale yellow) whose properties are very similar to the heavier elements in its group, strontium, barium, and radium. A calcium atom has twenty electrons, wit...	{ "page_id": 5668, "title": "Calcium" }
443 °C (716 K), it changes to a body-centered cubic. Its density of 1.526 g/cm3 (at 20 °C) is the lowest in its group. Calcium is harder than lead but can be cut with a knife with effort. While calcium is a poorer conductor of electricity than copper or aluminium by volume, it is a better conductor by mass than both du...	{ "page_id": 5668, "title": "Calcium" }
the calcium ion (Ca2+), high coordination numbers are common, up to 24 in some intermetallic compounds such as CaZn13. Calcium is readily complexed by oxygen chelates such as EDTA and polyphosphates, which are useful in analytic chemistry and removing calcium ions from hard water. In the absence of steric hindrance, sm...	{ "page_id": 5668, "title": "Calcium" }
the decay of primordial 40K. Adding another alpha particle leads to unstable 44Ti, which decays via two successive electron captures to stable 44Ca; this makes up 2.806% of all natural calcium and is the second-most common isotope. The other four natural isotopes, 42Ca, 43Ca, 46Ca, and 48Ca, are significantly rarer, ea...	{ "page_id": 5668, "title": "Calcium" }
has likewise never been observed. Calcium is the only element with two primordial doubly magic isotopes. The experimental lower limits for the half-lives of 40Ca and 46Ca are 5.9 × 1021 years and 2.8 × 1015 years respectively. Apart from the practically stable 48Ca, the longest lived radioisotope of calcium is 41Ca. It...	{ "page_id": 5668, "title": "Calcium" }
known for millennia, though their chemical makeup was not understood until the 17th century. Lime as a building material and as plaster for statues was used as far back as around 7000 BC. The first dated lime kiln dates back to 2500 BC and was found in Khafajah, Mesopotamia. About the same time, dehydrated gypsum (CaSO...	{ "page_id": 5668, "title": "Calcium" }
properties nearly approaching to those of metallic bodies. It is even possible that all the substances we call earths may be only metallic oxyds, irreducible by any hitherto known process. Calcium, along with its congeners magnesium, strontium, and barium, was first isolated by Humphry Davy in 1808. Following the work ...	{ "page_id": 5668, "title": "Calcium" }
United States (about 2000 to 4000 tonnes per year). Canada and France are also among the minor producers. In 2005, about 24000 tonnes of calcium were produced; about half of the world's extracted calcium is used by the United States, with about 80% of the output used each year. In Russia and China, Davy's method of ele...	{ "page_id": 5668, "title": "Calcium" }
that forms when CO2 reacts with water at seawater pH: Ca2+ + 2 HCO−3 → CaCO3↓ + CO2 + H2O At seawater pH, most of the dissolved CO2 is immediately converted back into HCO−3. The reaction results in a net transport of one molecule of CO2 from the ocean/atmosphere into the lithosphere. The result is that each Ca2+ ion re...	{ "page_id": 5668, "title": "Calcium" }
exploited to remove nitrogen from high-purity argon gas and as a getter for oxygen and nitrogen. It is also used as a reducing agent in the production of chromium, zirconium, thorium, vanadium and uranium. It can also be used to store hydrogen gas, as it reacts with hydrogen to form solid calcium hydride, from which th...	{ "page_id": 5668, "title": "Calcium" }
closely tied to the carbon cycle. Many calcium compounds are used in food, as pharmaceuticals, and in medicine, among others. For example, calcium and phosphorus are supplemented in foods through the addition of calcium lactate, calcium diphosphate, and tricalcium phosphate. The last is also used as a polishing agent i...	{ "page_id": 5668, "title": "Calcium" }
of bone in the form of hydroxyapatite; and supports synthesis and function of blood cells. For example, it regulates the contraction of muscles, nerve conduction, and the clotting of blood. As a result, intra- and extracellular calcium levels are tightly regulated by the body. Calcium can play this role because the Ca2...	{ "page_id": 5668, "title": "Calcium" }
and calcium gluconate. The intestine absorbs about one-third of calcium eaten as the free ion, and plasma calcium level is then regulated by the kidneys. === Hormonal regulation of bone formation and serum levels === Parathyroid hormone and vitamin D promote the formation of bone by allowing and enhancing the depositio...	{ "page_id": 5668, "title": "Calcium" }
can be traced to the organic matrix or the hydroxyapatite in molecular structure or organization of bone. Osteoporosis is a reduction in mineral content of bone per unit volume, and can be treated by supplementation of calcium, vitamin D, and bisphosphonates. Inadequate amounts of calcium, vitamin D, or phosphates can ...	{ "page_id": 5668, "title": "Calcium" }
Chromium is a chemical element; it has symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal. Chromium is valued for its high corrosion resistance and hardness. A major development in steel production was the discovery that steel could be m...	{ "page_id": 5669, "title": "Chromium" }
== === Atomic === Gaseous chromium has a ground-state electron configuration of [Ar] 3d5 4s1. It is the first element in the periodic table whose configuration violates the Aufbau principle. Exceptions to the principle also occur later in the periodic table for elements such as copper, niobium and molybdenum. Chromium ...	{ "page_id": 5669, "title": "Chromium" }
62% at 750 μm before rising again to 90% at 4000 μm. When chromium is used in stainless steel alloys and polished, the specular reflection decreases with the inclusion of additional metals, yet is still high in comparison with other alloys. Between 40% and 60% of the visible spectrum is reflected from polished stainles...	{ "page_id": 5669, "title": "Chromium" }
growing in thickness by outward diffusion of metal ions across the scale. Above 950 °C volatile chromium trioxide CrO3 forms from the chromia scale, limiting the scale thickness and oxidation protection. Chromium, unlike iron and nickel, does not suffer from hydrogen embrittlement. However, it does suffer from nitrogen...	{ "page_id": 5669, "title": "Chromium" }
Chromium is a member of group 6, of the transition metals. The +3 and +6 states occur most commonly within chromium compounds, followed by +2; charges of +1, +4 and +5 for chromium are rare, but do nevertheless occasionally exist. === Common oxidation states === ==== Chromium(0) ==== Many Cr(0) complexes are known. Bis...	{ "page_id": 5669, "title": "Chromium" }
has been reported for the Cr-centered Keggin anion [α-CrW12O40]5–. Chromium(III) hydroxide (Cr(OH)3) is amphoteric, dissolving in acidic solutions to form [Cr(H2O)6]3+, and in basic solutions to form [Cr(OH)6]3−. It is dehydrated by heating to form the green chromium(III) oxide (Cr2O3), a stable oxide with a crystal st...	{ "page_id": 5669, "title": "Chromium" }
CrO3, the acid anhydride of chromic acid, is sold industrially as "chromic acid". It can be produced by mixing sulfuric acid with dichromate and is a strong oxidizing agent. === Other oxidation states === Compounds of chromium(V) are rather rare; the oxidation state +5 is only realized in few compounds but are intermed...	{ "page_id": 5669, "title": "Chromium" }
are: atmosphere <10 ng/m3; soil <500 mg/kg; vegetation <0.5 mg/kg; freshwater <10 μg/L; seawater <1 μg/L; sediment <80 mg/kg. Chromium is mined as chromite (FeCr2O4) ore. About two-fifths of the chromite ores and concentrates in the world are produced in South Africa, about a third in Kazakhstan, while India, Russia, a...	{ "page_id": 5669, "title": "Chromium" }
red lead. Though misidentified as a lead compound with selenium and iron components, the mineral was in fact crocoite with a formula of PbCrO4. In 1770, Peter Simon Pallas visited the same site as Lehmann and found a red lead mineral that was discovered to possess useful properties as a pigment in paints. After Pallas,...	{ "page_id": 5669, "title": "Chromium" }
and many other items, usually applied by electroplating. Chromium was used for electroplating as early as 1848, but this use only became widespread with the development of an improved process in 1924. == Production == Approximately 28.8 million metric tons (Mt) of marketable chromite ore was produced in 2013, and conve...	{ "page_id": 5669, "title": "Chromium" }
chromium. Na2Cr2O7 + 2 C → Cr2O3 + Na2CO3 + CO Cr2O3 + 2 Al → Al2O3 + 2 Cr == Applications == The creation of metal alloys account for 85% of the available chromium's usage. The remainder of chromium is used in the chemical, refractory, and foundry industries. === Metallurgy === The strengthening effect of forming stab...	{ "page_id": 5669, "title": "Chromium" }
hands of Nazi Germany. The high hardness and corrosion resistance of unalloyed chromium makes it a reliable metal for surface coating; it is still the most popular metal for sheet coating, with its above-average durability, compared to other coating metals. A layer of chromium is deposited on pretreated metallic surfac...	{ "page_id": 5669, "title": "Chromium" }
Pigment === The mineral crocoite (which is also lead chromate PbCrO4) was used as a yellow pigment shortly after its discovery. After a synthesis method became available starting from the more abundant chromite, chrome yellow was, together with cadmium yellow, one of the most used yellow pigments. The pigment does not ...	{ "page_id": 5669, "title": "Chromium" }
lightfast and as such is used in cladding coatings. It is also the main ingredient in infrared reflecting paints, used by the armed forces to paint vehicles and to give them the same infrared reflectance as green leaves. === Other uses === Chromium(III) ions present in corundum crystals (aluminium oxide) cause them to ...	{ "page_id": 5669, "title": "Chromium" }
chromite and chromium(III) oxide a material for high temperature refractory applications, like blast furnaces, cement kilns, molds for the firing of bricks and as foundry sands for the casting of metals. In these applications, the refractory materials are made from mixtures of chromite and magnesite. The use is declini...	{ "page_id": 5669, "title": "Chromium" }
fabric and in tanning. == Biological role == The possible nutritional value of chromium(III) is unproven. Although chromium is regarded as a trace element and dietary mineral, its suspected roles in the action of insulin – a hormone that mediates the metabolism and storage of carbohydrate, fat, and protein – have not b...	{ "page_id": 5669, "title": "Chromium" }
Estimated Average Requirements (EARs) and the Recommended Dietary Allowances (RDAs) for chromium in 2001. For chromium, there was insufficient information to set EARs and RDAs, so its needs are described as estimates for Adequate Intake (AI). From a 2001 assessment, AI of chromium for women ages 14 through 50 is 25 μg/...	{ "page_id": 5669, "title": "Chromium" }
dietary supplement labeling purposes, the amount of the substance in a serving is expressed as a percent of the Daily Value (%DV). For chromium labeling purposes, 100% of the Daily Value was 120 μg. As of 27 May 2016, the percentage of daily value was revised to 35 μg to bring the chromium intake into a consensus with ...	{ "page_id": 5669, "title": "Chromium" }
amounts ranging from 50 to 1,000 μg. Lower amounts of chromium are also often incorporated into multi-vitamin/mineral supplements consumed by an estimated 31% of adults in the United States. Chemical compounds used in dietary supplements include chromium chloride, chromium citrate, chromium(III) picolinate, chromium(II...	{ "page_id": 5669, "title": "Chromium" }
helps the body to metabolize fats. The European Food Safety Authority approved claims in 2010 that chromium contributed to normal macronutrient metabolism and maintenance of normal blood glucose concentration, but rejected claims for maintenance or achievement of a normal body weight, or reduction of tiredness or fatig...	{ "page_id": 5669, "title": "Chromium" }
obese people. One, limited to chromium picolinate, a common supplement ingredient, reported a statistically significant −1.1 kg (2.4 lb) weight loss in trials longer than 12 weeks. The other included all chromium compounds and reported a statistically significant −0.50 kg (1.1 lb) weight change. Change in percent body ...	{ "page_id": 5669, "title": "Chromium" }
In adult fish there are reports of histopathological damage to liver, kidney, muscle, intestines, and gills. Mechanisms include mutagenic gene damage and disruptions of enzyme functions. There is evidence that fish may not require chromium, but benefit from a measured amount in diet. In one study, juvenile fish gained ...	{ "page_id": 5669, "title": "Chromium" }
cell. The acute toxicity of chromium(VI) is due to its strong oxidant properties. After it reaches the blood stream, it damages the kidneys, the liver and blood cells through oxidation reactions. Hemolysis, renal, and liver failure result. Aggressive dialysis can be therapeutic. The carcinogenity of chromate dust has b...	{ "page_id": 5669, "title": "Chromium" }
the tap water of 31 of the cities sampled, with Norman, Oklahoma, at the top of list; 25 cities had levels that exceeded California's proposed limit. The more toxic hexavalent chromium form can be reduced to the less soluble trivalent oxidation state in soils by organic matter, ferrous iron, sulfides, and other reducin...	{ "page_id": 5669, "title": "Chromium" }
Cadmium is a chemical element; it has symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of its compounds, and like mercury, it has a lower melting point than the transit...	{ "page_id": 5672, "title": "Cadmium" }
is resistant to corrosion and is used as a protective plate on other metals. As a bulk metal, cadmium is insoluble in water and is not flammable; however, in its powdered form it may burn and release toxic fumes. === Chemical properties === Although cadmium usually has an oxidation state of +2, it also exists in the +1...	{ "page_id": 5672, "title": "Cadmium" }
long-lived are 109Cd with a half-life of 462.6 days, and 115Cd with a half-life of 53.46 hours. All of the remaining radioactive isotopes have half-lives of less than 2.5 hours, and the majority have half-lives of less than 5 minutes. Cadmium has 8 known meta states, with the most stable being 113mCd (t1⁄2 = 14.1 years...	{ "page_id": 5672, "title": "Cadmium" }
an impurity in zinc carbonate (calamine), and, for 100 years, Germany remained the only important producer of the metal. The metal was named after the Latin word for calamine, because it was found in this zinc ore. Stromeyer noted that some impure samples of calamine changed color when heated but pure calamine did not....	{ "page_id": 5672, "title": "Cadmium" }
and health regulations in the 1980s and 1990s; in 2006, only 7% of total cadmium consumption was used for plating, and only 10% was used for pigments. At the same time, these decreases in consumption were compensated by a growing demand for cadmium for nickel–cadmium batteries, which accounted for 81% of the cadmium co...	{ "page_id": 5672, "title": "Cadmium" }
brands of dark chocolate sold in the United States in 2022, and found cadmium in all of them, with 13 exceeding the California Maximum Allowable Dose level. Some plants such as willow trees and poplars have been found to clean both lead and cadmium from soil. Typical background concentrations of cadmium do not exceed 5...	{ "page_id": 5672, "title": "Cadmium" }
an alkaline electrolyte (potassium hydroxide). The European Union put a limit on cadmium in electronics in 2004 of 0.01%, with some exceptions, and in 2006 reduced the limit on cadmium content to 0.002%. Another type of battery based on cadmium is the silver–cadmium battery. === Electroplating === Cadmium electroplatin...	{ "page_id": 5672, "title": "Cadmium" }
was used in black and white television phosphors and in the blue and green phosphors of color television cathode ray tubes. Cadmium sulfide (CdS) is used as a photoconductive surface coating for photocopier drums. Various cadmium salts are used in paint pigments, with CdS as a yellow pigment being the most common. Cadm...	{ "page_id": 5672, "title": "Cadmium" }
as well as various laboratory uses requiring laser light at these wavelengths. Cadmium selenide quantum dots emit bright luminescence under UV excitation (He–Cd laser, for example). The color of this luminescence can be green, yellow or red depending on the particle size. Colloidal solutions of those particles are used...	{ "page_id": 5672, "title": "Cadmium" }
dangerous form of occupational exposure to cadmium is inhalation of fine dust and fumes, or ingestion of highly soluble cadmium compounds. Inhalation of cadmium fumes can result initially in metal fume fever, but may progress to chemical pneumonitis, pulmonary edema, and death. Cadmium is also an environmental hazard. ...	{ "page_id": 5672, "title": "Cadmium" }
The International Agency for Research on Cancer has classified cadmium and cadmium compounds as carcinogenic to humans. Although occupational exposure to cadmium is linked to lung and prostate cancer, there is still uncertainty about the carcinogenicity of cadmium in low environmental exposure. Recent data from epidemi...	{ "page_id": 5672, "title": "Cadmium" }
the high cadmium content in cigarette smoke, there seems to be little exposure to cadmium from passive smoking. In a non-smoking population, food accounts for around 90% of cadmium uptake. High quantities of cadmium can be found in crustaceans, mollusks, offal, frog legs, cocoa solids, bitter and semi-bitter chocolate,...	{ "page_id": 5672, "title": "Cadmium" }
cadmium on products such as cocoa powder. The European Commission has put in place the EU regulation (2019/1009) on fertilizing products (EU, 2019), adopted in June 2019 and fully applicable as of July 2022. It sets a Cd limit value in phosphate fertilizers to 60 mg kg−1 of P2O5. The U.S. Occupational Safety and Health...	{ "page_id": 5672, "title": "Cadmium" }
Springer. pp. 491–507. doi:10.1007/978-94-007-5179-8_15. ISBN 978-94-007-5178-1. PMID 23430782. Agency for Toxic Substances and Disease Registry (ATSDR) (2012). Toxicological Profile for Cadmium. U.S. Department of Health and Human Services, Public Health Service. https://www.atsdr.cdc.gov/toxprofiles/tp5.pdf Nordberg,...	{ "page_id": 5672, "title": "Cadmium" }
Crystal structures of protein and nucleic acid molecules and their complexes are central to the practice of most parts of biophysics, and have shaped much of what we understand scientifically at the atomic-detail level of biology. Their importance is underlined by the United Nations declaring 2014 as the International ...	{ "page_id": 41883177, "title": "List of biophysically important macromolecular crystal structures" }
at higher resolution (PDB 1MHB, 1DHB) soon showed the coupled change of both local and quaternary conformation between the oxy and deoxy states of hemoglobin, which explains the cooperativity of oxygen binding in the blood and the allosteric effect of factors such as pH and DPG. For decades hemoglobin was the primary t...	{ "page_id": 41883177, "title": "List of biophysically important macromolecular crystal structures" }
protein's 3-dimensional structure was determined by its amino-acid sequence. Ribonuclease S, the cleaved, two-component form studied by Fred Richards, was also enzymatically active, had a nearly identical crystal structure (PDB file 1RNS), and was shown to be catalytically active even in the crystal, helping dispel dou...	{ "page_id": 41883177, "title": "List of biophysically important macromolecular crystal structures" }
the enzyme from sucking in the chain past the first residue. == Subtilisin == 1969 – Subtilisin (PDB file 1sbt ) was a second type of serine protease with a near-identical active site to the trypsin family of enzymes, but with a completely different overall fold. This gave the first view of convergent evolution at the ...	{ "page_id": 41883177, "title": "List of biophysically important macromolecular crystal structures" }
to fold up as the active 2-chain, SS-linked monomer. Insulin was a success of NASA's crystal-growth program on the Space Shuttle, producing bulk preparations of very uniform tiny crystals for controlled dosage. == Staphylococcal nuclease == 1971 – Staphylococcal nuclease == Cytochrome C == 1971 – Cytochrome C == T4 pha...	{ "page_id": 41883177, "title": "List of biophysically important macromolecular crystal structures" }
too tightly during normal cellular processes such as the transcription of genetic information. 1998 – Tubulin alpha/beta dimer 1998 – Potassium channel 1998 – Holliday junction 2000 – Ribosomes are a central part of biology and biophysics, which first became accessible structurally in 2000 2000 – AAA+ ATPase 2002 – Ank...	{ "page_id": 41883177, "title": "List of biophysically important macromolecular crystal structures" }
Stelpaviricetes is a class of non-enveloped, positive-strand RNA viruses which infect plants and animals. Characteristic of the group is a VPg protein attached to the 5'-end of the genome and a conserved 3C-like protease from the PA clan of proteases for processing the translated polyprotein. The name of the group is a...	{ "page_id": 63772201, "title": "Stelpaviricetes" }
The Sakaguchi test is a chemical test used to detect presence of arginine in proteins. It is named after the Japanese food scientist and organic chemist, Shoyo Sakaguchi (1900–1995) who described the test in 1925. The Sakaguchi reagent used in the test consists of 1-Naphthol and a drop of sodium hypobromite. The guanid...	{ "page_id": 42407465, "title": "Sakaguchi test" }
Curium is a synthetic chemical element; it has symbol Cm and atomic number 96. This transuranic actinide element was named after eminent scientists Marie and Pierre Curie, both known for their research on radioactivity. Curium was first intentionally made by the team of Glenn T. Seaborg, Ralph A. James, and Albert Ghio...	{ "page_id": 5675, "title": "Curium" }
is used in making heavier actinides and the 238Pu radionuclide for power sources in artificial cardiac pacemakers and RTGs for spacecraft. It served as the α-source in the alpha particle X-ray spectrometers of several space probes, including the Sojourner, Spirit, Opportunity, and Curiosity Mars rovers and the Philae l...	{ "page_id": 5675, "title": "Curium" }
⟶ Cm 96 242 + n 0 1 {\displaystyle {\ce {^{239}_{94}Pu + ^{4}_{2}He -> ^{242}_{96}Cm + ^{1}_{0}n}}} Curium-242 was unambiguously identified by the characteristic energy of the α-particles emitted during the decay: Cm 96 242 ⟶ Pu 94 238 + He 2 4 {\displaystyle {\ce {^{242}_{96}Cm -> ^{238}_{94}Pu + ^{4}_{2}He}}} The hal...	{ "page_id": 5675, "title": "Curium" }
seven 5f electrons and is thus analogous to the element gadolinium, with its seven 4f electrons in the regular rare earth series. On this basis element 96 is named after the Curies in a manner analogous to the naming of gadolinium, in which the chemist Gadolin was honored. The first curium samples were barely visible, ...	{ "page_id": 5675, "title": "Curium" }
which has face-centered cubic symmetry, space group Fm3m and lattice constant a = 493 pm. On further compression to 43 GPa, curium becomes an orthorhombic γ-Cm structure similar to α-uranium, with no further transitions observed up to 52 GPa. These three curium phases are also called Cm I, II and III. Curium has peculi...	{ "page_id": 5675, "title": "Curium" }
has a +3 oxidation state, the most stable oxidation state for curium. A +4 oxidation state is seen mainly in a few solid phases, such as CmO2 and CmF4. Aqueous curium(IV) is only known in the presence of strong oxidizers such as potassium persulfate, and is easily reduced to curium(III) by radiolysis and even by water ...	{ "page_id": 5675, "title": "Curium" }
as 250Cm, undergo a self-sustaining nuclear chain reaction and thus in principle can be a nuclear fuel in a reactor. As in most transuranic elements, nuclear fission cross section is especially high for the odd-mass curium isotopes 243Cm, 245Cm and 247Cm. These can be used in thermal-neutron reactors, whereas a mixture...	{ "page_id": 5675, "title": "Curium" }
but none are known to have been made. Curium-243 is not suitable for such, due to its short half-life and strong α emission, which would cause excessive heat. Curium-247 would be highly suitable due to its long half-life, which is 647 times longer than plutonium-239 (used in many existing nuclear weapons). === Occurren...	{ "page_id": 5675, "title": "Curium" }
Soil analysis revealed about 4,000 times higher concentration of curium at the sandy soil particles than in water present in the soil pores. An even higher ratio of about 18,000 was measured in loam soils. The transuranium elements from americium to fermium, including curium, occurred naturally in the natural nuclear f...	{ "page_id": 5675, "title": "Curium" }
the intermediate 249Cm (64 min), which β− decays to the berkelium isotope 249Bk. The above cascade of (n,γ) reactions gives a mix of different curium isotopes. Their post-synthesis separation is cumbersome, so a selective synthesis is desired. Curium-248 is favored for research purposes due to its long half-life. The m...	{ "page_id": 5675, "title": "Curium" }
curium stays unchanged and so can be isolated by repeated centrifugation. Metallic curium is obtained by reduction of its compounds. Initially, curium(III) fluoride was used for this purpose. The reaction was done in an environment free of water and oxygen, in an apparatus made of tantalum and tungsten, using elemental...	{ "page_id": 5675, "title": "Curium" }
CmO4, with curium in the extremely rare +8 state; but new experiments seem to indicate that CmO4 does not exist, and have cast doubt on the existence of PuO4 as well. === Halides === The colorless curium(III) fluoride (CmF3) can be made by adding fluoride ions into curium(III)-containing solutions. The brown tetravalen...	{ "page_id": 5675, "title": "Curium" }
They can be prepared by reacting either curium(III) hydride (CmH3) or metallic curium with these elements at elevated temperature. === Organocurium compounds and biological aspects === Organometallic complexes analogous to uranocene are known also for other actinides, such as thorium, protactinium, neptunium, plutonium...	{ "page_id": 5675, "title": "Curium" }
2000 USD/g. 243Cm with a ~30-year half-life and good energy yield of ~1.6 W/g could be a suitable fuel, but it gives significant amounts of harmful gamma and beta rays from radioactive decay products. As an α-emitter, 244Cm needs much less radiation shielding, but it has a high spontaneous fission rate, and thus a lot ...	{ "page_id": 5675, "title": "Curium" }
nuclear fuel cycle, helping to reduce the long-term radiotoxicity of used, or spent nuclear fuel. === X-ray spectrometer === The most practical application of 244Cm—though rather limited in total volume—is as α-particle source in alpha particle X-ray spectrometers (APXS). These instruments were installed on the Sojourn...	{ "page_id": 5675, "title": "Curium" }
and 50 years in the bones. Curium is absorbed in the body much more strongly via inhalation, and the allowed total dose of 244Cm in soluble form is 0.3 μCi. Intravenous injection of 242Cm- and 244Cm-containing solutions to rats increased the incidence of bone tumor, and inhalation promoted lung and liver cancer. Curium...	{ "page_id": 5675, "title": "Curium" }
Sodium ions (Na+) are necessary in small amounts for some types of plants, but sodium as a nutrient is more generally needed in larger amounts by animals, due to their use of it for generation of nerve impulses and for maintenance of electrolyte balance and fluid balance. In animals, sodium ions are necessary for the a...	{ "page_id": 22615598, "title": "Sodium in biology" }
g sodium would be about 5.9 g of salt—about 1 teaspoon. The average daily excretion of sodium is between 40 and 220 mEq. Normal serum sodium levels are between approximately 135 and 145 mEq/L (135 to 145 mmol/L). A serum sodium level of less than 135 mEq/L qualifies as hyponatremia, which is considered severe when the ...	{ "page_id": 22615598, "title": "Sodium in biology" }
the sodium ion as "salty." Receptors for the pure salty taste respond best to sodium; otherwise, the receptors respond only to a few other small monovalent cations (Li+, NH+4 and somewhat to K+). The calcium ion (Ca2+) also tastes salty and sometimes bitter to some people but, like potassium, can trigger other tastes. ...	{ "page_id": 22615598, "title": "Sodium in biology" }
what it is normally in extracellular body fluids. === Sodium and water balance in humans === Although the system for maintaining optimal salt and water balance in the body is a complex one, one of the primary ways in which the human body keeps track of loss of body water is that osmoreceptors in the hypothalamus sense ...	{ "page_id": 22615598, "title": "Sodium in biology" }
accompanied by an excretion of body water (water loss accompanies sodium loss). This happens because the kidney is unable to efficiently retain water while excreting large amounts of sodium. In addition, after sodium excretion, the osmoreceptor system may sense lowered sodium concentration in the blood and then direct ...	{ "page_id": 22615598, "title": "Sodium in biology" }
patients found to have a lowered amount of magnesium and potassium also had a decreased concentration of the sodium-potassium pump in skeletal and smooth muscle during respiratory failure. COLD is treatable in the short term by glucocorticoid which up-regulates the sodium-potassium pump, helping to support muscle endur...	{ "page_id": 22615598, "title": "Sodium in biology" }
is defective and only binds a single ATP, leading to the channel failing to open and preventing chloride ions from diffusing into the airway lumen. Since chloride ions cannot diffuse in, there is no movement of sodium into the airway lumen, and no need for water to move into the lumen, leading to thick mucus that clogs...	{ "page_id": 22615598, "title": "Sodium in biology" }
Instruments used specially in Toxicology are as follows: == Instrument list == == References ==	{ "page_id": 21370414, "title": "List of instruments used in toxicology" }
B-lymphocyte antigen CD19, also known as CD19 molecule (Cluster of Differentiation 19), B-Lymphocyte Surface Antigen B4, T-Cell Surface Antigen Leu-12 and CVID3 is a transmembrane protein that in humans is encoded by the gene CD19. In humans, CD19 is expressed in all B lineage cells. Contrary to some early doubts, huma...	{ "page_id": 9377328, "title": "CD19" }
is widely expressed during all phases of B cell development until terminal differentiation into plasma cells. During B cell lymphopoiesis, CD19 surface expression starts during immunoglobulin (Ig) gene rearrangement, which coincides during B lineage commitment from hematopoietic stem cell. Throughout development, the s...	{ "page_id": 9377328, "title": "CD19" }

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