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urine

(Encyclopedia)urine, clear, amber-colored fluid formed by the kidneys that carries metabolic wastes out of the body (see urinary system). As the blood circulates it collects excretory products from the tissues and ...

topaz

(Encyclopedia)topaz tōˈpăz [key], aluminum silicate mineral with either hydroxyl radicals or fluorine, Al2SiO4(F,OH)2, used as a gem. It is commonly colorless or some shade of pale yellow to wine-yellow; pale bl...

peroxide

(Encyclopedia)peroxide pərŏkˈsīd [key], chemical compound containing two oxygen atoms, each of which is bonded to the other and to a radical or some element other than oxygen; e.g., in hydrogen peroxide, H2O2, ...

differentiation

(Encyclopedia)differentiation, in biology, series of changes that occur in cells and tissues during development, resulting in their specialization. This, in turn, permits a greater variety of organisms. In plants, ...

Duane, William, American journalist

(Encyclopedia)Duane, William, 1760–1835, American journalist, b. near Lake Champlain, N.Y., of Irish parentage. He learned the printer's trade in Ireland and in 1787 went to Calcutta (now Kolkata), where he edite...

histamine

(Encyclopedia)histamine hĭsˈtəmēnˌ [key], organic compound derived in the body from the amino acid histidine by the removal of a carboxyl group (COOH). Although found in many plant and animal tissues, histamin...

histone

(Encyclopedia)histone hĭsˈtōn [key], any of a class of protein molecules found in the chromosomes of eukaryotic cells. They complex with the DNA (see nucleic acid) and pack the DNA into tight masses of chromatin...

ergot

(Encyclopedia)ergot ûrˈgət [key], disease of rye and other cereals caused by the fungus Claviceps purpurea. The cottony, matlike body, or mycelium, of the fungus develops in the ovaries of the host plant; it eve...

Nirenberg, Marshall Warren

(Encyclopedia)Nirenberg, Marshall Warren, 1927–2010, American biochemist, b. Brooklyn, N.Y., Ph.D., Univ. of Michigan, 1947. He spent his entire career as a researcher at the National Institutes of Health. Nirenb...

nitrobenzene

(Encyclopedia)nitrobenzene, C6H5NO2, very poisonous, flammable, pale yellow, liquid aromatic compound with an odor like that of bitter almonds. It is sometimes called oil of mirbane or nitrobenzol. Nitrobenzene mel...