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leaching

(Encyclopedia)leaching, method of extraction in which a solvent is passed through a mixture to remove some desired substance from it. A simple example is the passage of boiling water through ground coffee to dissol...

Metchnikoff, Élie

(Encyclopedia)Metchnikoff, Élie ālēˈ mĕchˈnĭkôf [key], 1845–1916, Russian biologist. He studied in Russia and Germany, lectured at the Univ. of Odessa, and, after working with Pasteur in Paris, became (19...

medlar

(Encyclopedia)medlar mĕdˈlər [key], small deciduous tree (Mespilus germanica) of the family Rosaceae (rose family), native to Europe and Asia. It has luxuriant foliage and large white or pinkish flowers; in the ...

aquatint

(Encyclopedia)aquatint äˈkwətĭntˌ [key], etching technique. The plate is covered with a porous ground, or resist, through which acid bites many tiny pockmarks in the metal. If an area is to be completely white...

Holley, Robert William

(Encyclopedia)Holley, Robert William, 1922–93, American biochemist, b. Urbana, Ill., Ph.D. Cornell, 1947. He was a professor at Cornell (1948–68) before he joined (1968) the Salk Institute, and he continued an ...

Anfinsen, Christian Boehmer

(Encyclopedia)Anfinsen, Christian Boehmer, 1916–95, American biochemist, b. Monessen, Pa., Ph.D. Harvard Medical School, 1943. He spent the early years of his career in brief research and fellowship positions at ...

gibberellins

(Encyclopedia)gibberellins jĭbˌərĕlˈĭnz [key], a group of growth-regulating substances of plants, having complex chemical structure, of which the best known, gibberellic acid, is noted for its promotion of st...

galvanizing

(Encyclopedia)galvanizing, process of coating a metal, usually iron or steel, with a protective covering of zinc. Galvanized iron is prepared either by dipping iron, from which rust has been removed by the action o...

fluorite

(Encyclopedia)fluorite flo͞oˈərspär [key], mineral appearing in various colors, e.g., green, yellow-brown, rose, and red. Chemically, it is calcium fluoride, CaF2. Its crystals, commonly cubic, are transparent ...

Huaynaputina

(Encyclopedia)Huaynaputina, volcano, 15,912 ft (4,850 m) high, Moquegua region, S Peru, in the central Andes. A stratovolcano, it lies on the W rim of the Río Tambo canyon and has several ash cones within its crat...