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Borlaug, Norman Ernest

(Encyclopedia)Borlaug, Norman Ernest bôrˈlôg [key], 1914–2009, U.S. agronomist, b. near Saude, Iowa, grad. Univ. of Minn. (Ph.D., 1942). He worked as researcher with the E. I. du Pont Company until 1944, when ...

arginine

(Encyclopedia)CE5 arginine ärˈjənĭn [key], organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer participates in the biosynthesis of proteins. Its basic side ...

naphtha

(Encyclopedia)naphtha năpˈthə, năfˈ– [key], term usually restricted to a class of colorless, volatile, flammable liquid hydrocarbon mixtures. Obtained as one of the more volatile fractions in the fractional ...

free radical

(Encyclopedia)free radical, in chemistry, a molecule or atom that contains an unpaired electron but is neither positively nor negatively charged. Free radicals are usually highly reactive and unstable. They are pro...

Grubbs, Robert Howard

(Encyclopedia)Grubbs, Robert Howard, 1942–2021, American chemist, b. near Possum Trot, Ky., Univ. of Florida (B.S., 1963; M.S., 1965), Columbia, Univ. (Ph.D, 1968)....

ammonium group

(Encyclopedia)ammonium group, in chemistry, a positively charged nitrogen atom joined by single bonds to four other atoms or groups. The simplest ammonium group, NH4+, is formed by protonation of ammonia, NH3, e.g....

humus

(Encyclopedia)humus hyo͞oˈməs [key], organic matter that has decayed to a relatively stable, amorphous state. It is an important biological constituent of fertile soil. Humus is formed by the decomposing action ...

aliphatic compound

(Encyclopedia)aliphatic compound ălˌəfătˈĭk [key], any of a large class of organic compounds whose carbon atoms are joined together in straight or branched open chains rather than in rings. The hydrocarbons o...

Driesch, Hans Adolf Eduard

(Encyclopedia)Driesch, Hans Adolf Eduard häns äˈdôlf āˈdo͞oärt drēsh [key], 1867–1941, German philosopher, b. Bad Kreuznach, grad. (zoology) Univ. of Jena, 1889. His early interest in biology was gradual...

alloy

(Encyclopedia)alloy ălˈoi, əloiˈ [key] [O. Fr.,=combine], substance with metallic properties that consists of a metal fused with one or more metals or nonmetals. Alloys may be a homogeneous solid solution, a he...