chromium (redirected from chromium 51)

chromium /chro·mi·um/ (Cr) (kro´me-um) a chemical element, at. no. 24. It is an essential dietary trace element, but hexavalent chromium is carcinogenic.

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chromium 51  a radioactive isotope of chromium having a half-life of 27.7 days and decaying by electron capture with emission of gamma rays (0.32 MeV); it is used to label red blood cells for measurement of mass or volume, survival time, and sequestration studies, for the diagnosis of gastrointestinal bleeding, and to label platelets to study their survival.

chromium trioxide  chromic acid.

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chro·mi·um (krm-m)

n. Symbol Cr

A lustrous hard metallic element, resistant to tarnish and corrosion and found primarily in chromite. It is used to harden steel alloys, in decorative platings, and as a pigment in glass. Atomic number 24.

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chromium (Cr)

[krō′mē·əm]

Etymology: Gk, chroma, color

a hard, brittle metallic element. Its atomic number is 24; its atomic mass is 51.99. It does not occur naturally in pure form but exists in combination with iron and oxygen in chromite, a mineral found chiefly in Africa, Albania, Russia, and Turkey. Chromium strongly resists corrosion and is used extensively to plate other metals, harden steel, and, in combination with other elements, form colored compounds. Stainless steels are more than 10% chromium and strongly resist rusting. Traces of chromium occur in plants and animals, and there is evidence that this element may be important in human nutrition, especially in carbohydrate metabolism. Some experts estimate that the safe and adequate daily intake of chromium ranges from 0.1 to 0.2 mg, depending on the age of the individual. Workers in chromite mines are susceptible to pneumoconiosis caused by the inhalation of chromite dust particles that lodge in the lung. Chromate salts have been identified as potential carcinogens. Chromium 51 isotope is used in blood studies.

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chromium (Cr) [kro´me-um]

a chemical element, atomic number 24, atomic weight 51.996. (See Appendix 6.) It is an essential dietary trace element, but hexavalent chromium is carcinogenic.

chromium 51 a radioactive isotope of chromium having a half-life of 27.7 days and decaying by electron capture, emitting gamma rays. It is used to label red blood cells for measurement of red cell mass or volume, survival time, and sequestration studies, and for the diagnosis of gastrointestinal bleeding, and is used to label platelets to study their survival. Symbol ⁵¹Cr.

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chromium,

n an essential mineral that is associated with glucose tolerance, high cholesterol, blocked arteries, glaucoma, obesity, diabetes, and hypoglycemia. Not for use by chil-dren or pregnant or nursing women. Also called
chromium picolinate, chromium polynicotinate, or
chromium chloride.

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chromatography,

n any one of several processes for separating and analyzing various gaseous or dissolved chemical materials according to differences in their absorbency with respect to a specific substance.

chromium, (Cr),

n a hard, brittle, metallic element with an atomic number of 24 and an atomic weight of 51.996. Chromium strongly resists corrosion and is used extensively to plate other metals and as an alloy to harden steel. Stainless steels are more than 10% chromium.

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chromium

a chemical element, atomic number 24, atomic weight 51.996, symbol Cr. See Table 6.

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chromium-51

a radioisotope of chromium having a half-life of 27.8 days; used to label red blood cells to determine red cell volume and red cell survival time. Symbol ⁵¹Cr. See also cr⁵¹edta.

chromium nutritional deficiency

possibly causally related to the onset of diabetes mellitus in primates.

chromium trioxide

possibly carcinogenic in humans. See also chromate.