- * * *A metallic element chemically similar to sulfur, atomic no. 34, atomic wt. 78.96; an essential trace element toxic in large quantities; required for glutathione peroxidase and a few other enzymes; 75Se (half-life equal to 119.78 days) is used in scintography of the pancreas and parathyroid glands. [G. selene, moon]- s. sulfide a mixture of crystalline s. monosulfide and solid solutions of s. and sulfur in an amorphous form, containing 52–55.5% Se; used in the treatment of seborrhea of the scalp or dandruff; it is applied to the scalp as a suspension.
* * *se·le·ni·um sə-'lē-nē-əm n a nonmetallic element that resembles sulfur and tellurium chemically, causes poisoning in range animals when ingested by eating some plants growing in soils in which it occurs in quantity, and occurs in allotropic forms of which a gray stable form varies in electrical conductivity with the intensity of its illumination and is used in electronic devices symbol Se see ELEMENT (table)
* * *n.a trace element that is an essential component of the enzyme glutathione peroxidase, which catalyses the oxidation of glutathione by hydrogen peroxide. It thus has important antioxidant properties. Dietary deficiency of selenium results in cardiomyopathy. Symbol: Se.
* * *se·le·ni·um (Se) (sə-leґne-əm) [Gr. selēnē moon] a nonmetallic element resembling sulfur; atomic number, 34; atomic weight, 78.96. It is an essential mineral, being a constituent of the enzyme glutathione peroxidase, and believed to be closely associated with vitamin E in its functions. Selenium occurs in toxic levels in certain plants growing in soil with high concentrations of it, causing selenium poisoning (q.v.) in grazing animals. Dietary deficiency, occurring where the soil has a low sodium content, results in cardiomyopathy (see Keshan disease, under disease).
Medical dictionary. 2011.
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Selenium — (pronEng|səˈliniəm) is a chemical element with the atomic number 34, represented by the chemical symbol Se, an atomic mass of 78.96. It is a nonmetal, chemically related to sulfur and tellurium, and rarely occurs in its elemental state in nature … Wikipedia
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Selenium — Se*le ni*um, n. [NL., from Gr. selh nh the moon. So called because of its chemical analogy to tellurium (from L. tellus the earth), being, as it were, a companion to it.] (Chem.) A nonmetallic element of the sulphur group of atomic number 34,… … The Collaborative International Dictionary of English
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selenium — [sə lē′nē əm] n. [ModL: so named (1818) by BERZELIUS Baron Jöns Jakob < Gr selēnē, the moon (see SELENE) + IUM, by analogy with TELLURIUM, with which it was assoc. in the ore] a nonmetallic chemical element with several allotropic forms, used… … English World dictionary