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perfluoroalkyl and polyfluoroalkyl substances

(Encyclopedia)perfluoroalkyl and polyfluoroalkyl substances (PFAS), a group of several thousand synthetic organic chemical compounds made up of a chain of carbon atoms bonded to fluorine atoms. PFAS, which resist w...

peroxide

(Encyclopedia)peroxide pərŏkˈsīd [key], chemical compound containing two oxygen atoms, each of which is bonded to the other and to a radical or some element other than oxygen; e.g., in hydrogen peroxide, H2O2, ...

benzaldehyde

(Encyclopedia)benzaldehyde bĕnˌzēnkärˈbənəl [key], C6H5CHO, colorless liquid aldehyde with a characteristic almond odor. It boils at 180℃, is soluble in ethanol, but is insoluble in water. It is formed by ...

Nirenberg, Marshall Warren

(Encyclopedia)Nirenberg, Marshall Warren, 1927–2010, American biochemist, b. Brooklyn, N.Y., Ph.D., Univ. of Michigan, 1947. He spent his entire career as a researcher at the National Institutes of Health. Nirenb...

nitrobenzene

(Encyclopedia)nitrobenzene, C6H5NO2, very poisonous, flammable, pale yellow, liquid aromatic compound with an odor like that of bitter almonds. It is sometimes called oil of mirbane or nitrobenzol. Nitrobenzene mel...

nitroglycerin

(Encyclopedia)nitroglycerin nīˌtrōglĭsˈərĭn [key], C3H5N3O9, colorless, oily, highly explosive liquid. It is the nitric acid triester of glycerol and is more correctly called glycerol trinitrate. It is insol...

balsam

(Encyclopedia)balsam bôlˈsəm [key], fragrant resin obtained from various trees. The true balsams are semisolid and insoluble in water, but they are soluble in alcohol and partly so in hydrocarbons. They contain ...

differentiation

(Encyclopedia)differentiation, in biology, series of changes that occur in cells and tissues during development, resulting in their specialization. This, in turn, permits a greater variety of organisms. In plants, ...

ergot

(Encyclopedia)ergot ûrˈgət [key], disease of rye and other cereals caused by the fungus Claviceps purpurea. The cottony, matlike body, or mycelium, of the fungus develops in the ovaries of the host plant; it eve...

O'Hara, John

(Encyclopedia)O'Hara, John, 1905–70, American novelist and short-story writer, b. Pottsville, Pa. He worked at a number of jobs and ultimately became a newspaperman before the appearance of his first novel, Appoi...