B. mit TestNG. Occupational Safety and Health Administration, National Institute for Occupational Safety and Health, "Atomic weights of the elements 2013 (IUPAC Technical Report)", Magnetic susceptibility of the elements and inorganic compounds, "The NUBASE2016 evaluation of nuclear properties", "Lettre de M. Berzelius à M. Berthollet sur deux métaux nouveaux", "Effect of light on selenium during the passage of an electric current", "The need for selenite and molybdate in the formation of formic dehydrogenase by members of the Coli-aerogenes group of bacteria", "How Selenium Has Altered Our Understanding of the Genetic Code", 10.1579/0044-7447(2007)36[94:SGAH]2.0.CO;2, "How to use the world's scarce selenium resources efficiently to increase the selenium concentration in food", "Public Health Statement: Selenium – Production, Import/Export, Use, and Disposal", "Chemistry: Periodic Table: selenium: key information", "Selenium and Tellurium: Statistics and Information", "Radiography of Welds Using Selenium 75, Ir 192 and X-rays", "Aquatic selenium pollution is a global environmental safety issue", "Mercury, selenium and fish oils in marine food webs and implications for human health", "Review of selenium toxicity in the aquatic food chain", Linus Pauling Institute at Oregon State University, "Dietary and tissue selenium in relation to methylmercury toxicity", "Post-transcriptional defects of antioxidant selenoenzymes cause oxidative stress under methylmercury exposure", "Protective effect of selenite against methylmercury toxicity: observations concerning time, dose and route factors in the development of selenium attenuation", "Inhibition of the human thioredoxin system: A molecular mechanism of mercury toxicity", Strong antioxidant activity of the novel selenium-containing imidazole compound ″selenoneine″, "Discovery of the strong antioxidant selenoneine in tuna and selenium redox metabolism", "Mercury: selenium interactions and health implications", "Selenocysteine-containing proteins in mammals", "Evolutionary dynamics of eukaryotic selenoproteomes: large selenoproteomes may associate with aquatic life and small with terrestrial life", "Evolution of Dietary Antioxidant Defences", "Reconsidering the evolution of eukaryotic selenoproteins: a novel nonmammalian family with scattered phylogenetic distribution", "The microbial selenoproteome of the Sargasso Sea", "FDA Issues Final Rule to Add Selenium to List of Required Nutrients for Infant Formula", "Dietary Supplement Fact Sheet: Selenium", "Public Health Statement: Health Effects", "Polo pony selenium levels up to 20 times higher than normal", "A teratogenic deformity index for evaluating impacts of selenium on fish populations", "CDC - NIOSH Pocket Guide to Chemical Hazards - Selenium", "Effect of micronutrient status on natural killer cell immune function in healthy free-living subjects aged ≥90 y", "Selenium and iodine supplementation of rural Tibetan children affected by Kashin-Beck osteoarthropathy", National Institutes of Health page on Selenium, CDC - NIOSH Pocket Guide to Chemical Hazards, https://en.wikipedia.org/w/index.php?title=Selenium&oldid=1007421203, Biology and pharmacology of chemical elements, Articles with dead external links from November 2020, Short description is different from Wikidata, Wikipedia articles needing clarification from August 2018, Wikipedia articles needing clarification from November 2015, Articles with unsourced statements from June 2016, Pages using Sister project links with hidden wikidata, Creative Commons Attribution-ShareAlike License, grey metallic-looking, red, and vitreous black (not pictured) allotropes, This page was last edited on 18 February 2021, at 01:46. [126], Selenium deficiency can occur in patients with severely compromised intestinal function, those undergoing total parenteral nutrition, and[127] in those of advanced age (over 90). [107], Certain species of plants are considered indicators of high selenium content of the soil because they require high levels of selenium to thrive. Eine Besonderheit bildet HtmlUnit. Selenium forms two oxides: selenium dioxide (SeO2) and selenium trioxide (SeO3). The selenium cell was used in the photophone developed by Alexander Graham Bell in 1879. [64], Amorphous selenium (α-Se) thin films have found application as photoconductors in flat panel x-ray detectors. [118] The resultant high selenium levels in waterways were found to cause congenital disorders in oviparous species, including wetland birds[119] and fish. The WebDriverAPI, to run tests against web browsers on a server ma… National Research Council, Committee on Nutrient Requirements of Small Ruminants (2007). Oktober 2016 verfügbar. answer choices . In solution it ionizes to HSe−. Selenium transmits an electric current proportional to the amount of light falling on its surface. Selenium enzymes are involved in the small reducing molecules glutathione and thioredoxin. Analysis of blood levels of inorganic compounds in the supplement indicated the selenium concentrations were 10 to 15 times higher than normal in the blood samples, and 15 to 20 times higher than normal in the liver samples. [24], Selenium (Greek σελήνη selene meaning "Moon") was discovered in 1817 by Jöns Jacob Berzelius and Johan Gottlieb Gahn. Sie sind Derivate des Selenwasserstoffs (H2Se). [25] Both chemists owned a chemistry plant near Gripsholm, Sweden, producing sulfuric acid by the lead chamber process. Selenium tetrafluoride (Se F 4) is an inorganic compound.It is a colourless liquid that reacts readily with water. Tags: Question 13 . These materials are semiconductors. Selenium poisoning can be passed from parents to offspring through the egg, and selenium poisoning may persist for many generations. Hypoiodous acid. Dies kann in unterschiedlichen Programmiersprachen geschehen, wie z. The chemical formulas for covalent compounds are referred to as molecular formulas because these compounds exist as separate, discrete molecules. Zinc selenide was the first material for blue LEDs, but gallium nitride dominates that market. The binary compound Pcl³ is called. The main selenium indicator plants are Astragalus species (including some locoweeds), prince's plume (Stanleya sp. 8) phosphorus triiodide PI 3 Write the names for the following covalent compounds: 9) P 4S 5 tetraphosphorus pentasulfide 10) O 2 oxygen 11) SeF 6 selenium hexafluoride 12) Si 2Br 6 disilicon hexabromide 13) SCl 4 sulfur tetrachloride 14) CH 4 methane 15) B 2Si diboron monosilicide 16) NF 3 nitrogen trifluoride Home [19] Selenium reacts with fluorine to form selenium hexafluoride: In comparison with its sulfur counterpart (sulfur hexafluoride), selenium hexafluoride (SeF6) is more reactive and is a toxic pulmonary irritant. [106], The selenium content in the human body is believed to be in the 13–20 mg range. Das homöopathische Mittel wird eingesetzt bei geistigen Schwächezuständen und Nervosität, bei Entzündungen der männlichen Geschlechtsorgane und Störungen des Sexualtriebes, bei Kopfschmerzen, Akne und Haarausfall. The sulfoxide in sulfur chemistry is represented in selenium chemistry by the selenoxides (formula RSe(O)R), which are intermediates in organic synthesis, as illustrated by the selenoxide elimination reaction. 13444-85-4. Zum chemischen Element siehe, The Art of Unit Testing: Deutsche Ausgabe Seite 290, Automatisierte Testverfahren für web-basierte Anwendungen, https://de.wikipedia.org/w/index.php?title=Selenium&oldid=200212419, „Creative Commons Attribution/Share Alike“. The high bioaccumulation of selenium in aquatic environments cause large fish kills depending on the species in the affected area. For every tonne of manganese, an average 2 kg selenium oxide is used. The chronic toxic dose of selenite for humans is about 2400 to 3000 micrograms of selenium per day. During the 1980s, selenocysteine was shown to be encoded by the codon UGA. [55], Researchers found that application of selenium fertilizer to lettuce crops decreased the accumulation of lead and cadmium. B₃Si₂. Also naturally occurring is the long-lived primordial radionuclide 82Se, with a half-life of 9.2×1019 years. [134] Ruminants grazing certain forages, e.g., some white clover varieties containing cyanogenic glycosides, may have higher selenium requirements,[134] presumably because cyanide is released from the aglycone by glucosidase activity in the rumen[135] and glutathione peroxidases is deactivated by the cyanide acting on the glutathione moiety. For salmon, the optimal concentration of selenium is about 1 microgram selenium per gram of whole body weight. Although New Zealand soil has low levels of selenium, adverse health effects have not been detected in the residents. Zur gleichen Zeit entwickelte Simon Stewart bei ThoughtWorks die Browsersteuerung Webdriver. High doses of Se supplements in pregnant animals might disturb the Zn:Cu ratio and lead to Zn reduction; in such treatment cases, Zn levels should be monitored. Minerals that are pure selenide or selenate compounds are known but rare. Electrolytic metal refining is particularly productive of selenium as a byproduct, obtained from the anode mud of copper refineries. 2008 entwickelte Philippe Hanrigou "Selenium Grid", welches erlaubt, mehrere Selenium-Instanzen gleichzeitig auf einer unbegrenzten Anzahl an Rechnern laufen zu lassen. Q. Conclusions: Selenium can be measured by direct spectrophotometric determination of the triiodide anion resulting from the oxidation of iodide by selenium … Cl 5 O. Their use continued into the 1990s. In plants, it occurs as a bystander mineral[clarification needed], sometimes in toxic proportions in forage (some plants may accumulate selenium as a defense against being eaten by animals, but other plants, such as locoweed, require selenium, and their growth indicates the presence of selenium in soil). Substantial physiological changes may occur in fish with high tissue concentrations of selenium. In low doses, selenium has shown a beneficial effect on plant resistance to various environmental stress factors including drought, UV-B, soil salinity, and cold or hot temperatures. The WebDriverAPI, which you use to develop test scripts to interact with page and application elements 2. [clarification needed]. The chief commercial uses for selenium today are glassmaking and pigments. Die finale Version 3.0 ist seit dem 13. Selenium rectifiers were first used in 1933. Selenium is a component of the unusual amino acids selenocysteine and selenomethionine. [20] Molecular Formula. Dinitrogen tetrahydride. Further concentration through bioaccumulation occurs along the food chain, as predators consume selenium rich prey. One family of selenium-bearing molecules (the glutathione peroxidases) destroys peroxide and repairs damaged peroxidized cell membranes, using glutathione. Tags: Question 12 . Textbook solution for Chemistry: The Molecular Science 5th Edition John W. Moore Chapter 2 Problem 60QRT. B. in Java, .NET, Perl, PHP, Python, Ruby. Formulas Practice.

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