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magnetic resonance imaging

(Encyclopedia)magnetic resonance imaging (MRI), noninvasive diagnostic technique that uses nuclear magnetic resonance to produce cross-sectional images of organs and other internal body structures. The patient lies...

Payne-Gaposchkin, Cecilia

(Encyclopedia)Payne-Gaposchkin, Cecilia, 1900–1979, British-American astronomer, b. Wendover, England, as Cecilia Helena Payne. She studied at Cambridge and at the Harvard College Observatory, and in her doctoral...

sodium bicarbonate

(Encyclopedia)sodium bicarbonate or sodium hydrogen carbonate, chemical compound, NaHCO3, a white crystalline or granular powder, commonly known as bicarbonate of soda or baking soda. It is soluble in water and ver...

Wheeler, John Archibald

(Encyclopedia)Wheeler, John Archibald, 1911–2008, American physicist and educator, b. Jacksonville, Fla. Educated at Johns Hopkins (Ph.D., 1933), he joined the faculty at Princeton in 1938, and after 1976 was dir...

magnesium

(Encyclopedia)magnesium măgnēˈzēəm, –zhəm [key], metallic chemical element; symbol Mg; at. no. 12; at. wt. 24.3050; m.p. about 648.8℃; b.p. about 1,090℃; sp. gr. 1.738 at 20℃; valence +2. In 1808, Sir...

neostigmine

(Encyclopedia)neostigmine nēˌōstĭgˈmēn, –mĭn [key], drug used to mimic the effects of stimulation of the parasympathetic nervous system. Along with several other drugs that have a similar mode of action, i...

Klíma, Ivan

(Encyclopedia)Klíma, Ivan ēvänˈ klēmˈə [key], 1931–, Czech author, b. Prague as Ivan Kauders, grad. Charles Univ., Prague (1956). Of Jewish descent, Klíma spent 1941–45 in the Theresienstadt (now Terez�...

glucagon

(Encyclopedia)glucagon glo͞oˈkəgŏn [key], hormone secreted by the α cells of the islets of Langerhans, specific groups of cells in the pancreas. It tends to counteract the action of insulin, i.e., it raises th...

Vavilov, Nikolai Ivanovich

(Encyclopedia)Vavilov, Nikolai Ivanovich nyĭkəlīˈ ēväˈnəvĭch vəvēˈləf [key], 1887–1943?, Russian botanist and geneticist. He is reported to have died in a Soviet concentration camp after losing polit...

jelly and jam

(Encyclopedia)jelly and jam, gelatinous, sweet food prepared by preserving fresh fruits. Since most fresh fruits contain about 80% water and from 10% to 15% sugar, they are subject to fermentation. They may be pres...