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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...

Krebs cycle

(Encyclopedia)Krebs cycle, series of chemical reactions carried out in the living cell; in most higher animals, including humans, it is essential for the oxidative metabolism of glucose and other simple sugars. The...

maser

(Encyclopedia)maser māˈzər [key], device for creation, amplification, and transmission of an intense, highly focused beam of high-frequency radio waves. The name maser is an acronym for microwave amplification b...

iodine

(Encyclopedia)iodine īˈədīn, –dĭn [key] [Gr.,=violet], nonmetallic chemical element; symbol I; at. no. 53; at. wt. 126.90447; m.p. 113.5℃; b.p. 184.35℃; sp. gr. 4.93 at 20℃; valence −1, +1, +3, +5, o...

Line Islands

(Encyclopedia)Line Islands or Equatorial Islands, coral group, 43 sq mi (111 sq km), central and S Pacific. Once valuable for their guano deposits, the islands now have coconut groves, airfields, and meteorological...

methanol

(Encyclopedia)methanol, methyl alcohol, or wood alcohol, CH3OH, a colorless, flammable liquid that is miscible with water in all proportions. Methanol is a monohydric alcohol. It melts at −97.8℃ and boils at 6...

Munk, Walter Heinrich

(Encyclopedia)Munk, Walter Heinrich, 1917–2019, American oceanographer and geophysicist, b. Vienna (then in Austria-Hungary), B.S. California Institute of Technology, 1939, Ph.D Univ. of California, Los Angeles, ...