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Geim, Sir Andre Konstantinovich

(Encyclopedia)Geim, Sir Andre Konstantinovich, 1958–, Russian-born Dutch physicist, Ph.D. Russian Academy of Sciences, 1987. He was a professor at the Univ. of Nijmegen in the Netherlands from 1994 to 2001, when ...

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...

sudden infant death syndrome

(Encyclopedia)sudden infant death syndrome (SIDS) or crib death, sudden, unexpected, and unexplained death of an apparently healthy infant under one year of age (usually between two weeks and eight months old). SID...

tetraethyl lead

(Encyclopedia)tetraethyl lead tĕtˌrəĕthˈəl [key], (C2H5)4Pb, viscous, colorless, poisonous liquid. It is an organometallic compound prepared by reacting ethyl chloride with a sodium-lead alloy. When added to ...

pyridine

(Encyclopedia)pyridine ăzˈēn [key], C5H5N, colorless, flammable, toxic liquid with a putrid odor. It melts at −42℃ and boils at 115.5℃. Chemically, it is a heterocyclic aromatic tertiary amine (see under a...

Rhea, in astronomy

(Encyclopedia)Rhea, in astronomy, one of the named moons, or natural satellites, of Saturn. Also known as Saturn V (or S5), Rhea is 950 mi (1530 km) in diameter, orbits Saturn at a mean distance of 327,487 mi (527,...

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, ...

amino acid

(Encyclopedia)CE5 General formula of an amino acid CE5 Peptide bond between two molecules of the amino acid alanine amino acid əmēˈnō [key], any one of a class of simple organic compounds containin...

metabolite

(Encyclopedia)metabolite, organic compound that is a starting material in, an intermediate in, or an end product of metabolism. Starting materials are substances, usually small and of simple structure, absorbed by ...

artificial limb

(Encyclopedia)artificial limb, mechanical replacement for a missing limb. An artificial limb, called a prosthesis, must be light and flexible to permit easy movement, but must also be sufficiently sturdy to support...