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thorium

(Encyclopedia)thorium thôrˈēəm [key] [from Thor], radioactive chemical element; symbol Th; at. no. 90; mass number of most stable isotope 232; m.p. about 1,750℃; b.p. about 4,790℃; sp. gr. 11.7 at 20℃; va...

ketone

(Encyclopedia)CE5 Ketones ketone kēˈtōn [key], any of a class of organic compounds that contain the carbonyl group, C=O, and in which the carbonyl group is bonded only to carbon atoms. The general formula fo...

mustard gas

(Encyclopedia)mustard gas, chemical compound used as a poison gas in World War I. The burning sensation it causes on contact with the skin is similar to that caused by oil from black mustard seeds. The compound is ...

glycogen

(Encyclopedia)glycogen glīˈkəjən [key], starchlike polysaccharide (see carbohydrate) that is found in the liver and muscles of humans and the higher animals and in the cells of the lower animals. Chemically it ...

Sharpless, Karl Barry

(Encyclopedia)Sharpless, Karl Barry, 1941–, American chemist, b. Philadelphia, Ph.D. Stanford, 1968. Sharpless was a professor at the Massachusetts Institute of Technology (1970–77 and 1980–90) and at Stanfor...

catabolism

(Encyclopedia)catabolism kətăbˈəlĭzˌəm [key], subdivision of metabolism involving all degradative chemical reactions in the living cell. Large polymeric molecules such as polysaccharides, nucleic acids, and ...

plea bargaining

(Encyclopedia)plea bargaining, negotiation in which a defendant agrees to plead guilty to a criminal charge in exchange for concessions by the prosecutor (representing the state). The defendant waives the right to ...

marine engine

(Encyclopedia)marine engine, machine for the propulsion of watercraft. The earliest marine power plants, reciprocating steam engines, were used almost exclusively until the early 1900s. In later ship construction t...

Jehoahaz

(Encyclopedia)Jehoahaz jōˈəhăz [key]. 1 In Second Kings, king of Israel (c.821–805 b.c.), son and successor of Jehu. He presided over an era of severe reduction of territory and prestige for the northern king...

Rodgers, Christopher Raymond Perry

(Encyclopedia)Rodgers, Christopher Raymond Perry, 1819–92, American naval officer, b. Brooklyn, N.Y. Appointed midshipman in 1833, he served in the Mexican War. In the Civil War he took part in the Union reductio...