activation


activation
1. The act of rendering active. 2. An increase in the energy content of an atom or molecule, through the raising of temperature, absorption of light photons, etc., which renders that atom or molecule more reactive. 3. Techniques of stimulating the brain by light, sound, electricity, or chemical agents, in order to elicit abnormal activity in the electroencephalogram. 4. Stimulation of peripheral nerve fibers to the point that action potentials are initiated. 5. Stimulation of cell division in an ovum by fertilization or by artificial means. 6. The act of making radioactive. SEE ALSO: cross-section.
- amino acid a. the formation of the amino acyl adenylate derivative ( E.G., during protein biosynthesis).
- EEG a. the low voltage, fast pattern of attentive wakefulness.
- feedback a. inhibitory or antiinhibitory a. on an enzyme by an end product of a biochemical pathway in which that enzyme plays a part. For example, the a. of factors VIII and V by thrombin during blood clotting.
- feed-forward a. the a. or stimulation of an enzyme by a precursor of the substrate of that enzyme.
- gene a. the process of a. of a gene so that it is expressed at a particular time. This process is crucial in growth and development.

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ac·ti·va·tion (ak″tĭ-vaґshən) 1. the act or process of rendering active. 2. the transformation of a proenzyme into an active enzyme by the action of a kinase or another proenzyme. 3. the process by which the central nervous system is stimulated into activity through the mediation of the reticular activating system. 4. the deliberate induction of a pattern of electrical activity in the brain in electroencephalography.

Medical dictionary. 2011.

Look at other dictionaries:

  • activation — [ aktivasjɔ̃ ] n. f. • 1910; de activer 1 ♦ Chim. Opération consistant à augmenter les propriétés physiques ou chimiques d une substance (généralement en la soumettant à des radiations). Activation de l ergostérol, du charbon. Biochim. Activation …   Encyclopédie Universelle

  • activation — n. 1. the process of making active. Syn: energizing, activating [WordNet 1.5 2. making active and effective (as a bomb). [1913 Webster] Note: certain devices, as bombs or artillery shells, are designed to be unable to operate until a specific… …   The Collaborative International Dictionary of English

  • Activation — Activation. См. Активация. (Источник: «Металлы и сплавы. Справочник.» Под редакцией Ю.П. Солнцева; НПО Профессионал , НПО Мир и семья ; Санкт Петербург, 2003 г.) …   Словарь металлургических терминов

  • activation — (n.) 1906, noun of action from ACTIVATE (Cf. activate) (v.) …   Etymology dictionary

  • Activation — This article describes the term used in chemistry and biochemistry. : For activation (installing) of computer software, see product activation. : For activation (calling) of a subroutine in computing, see Subroutine. Activation in (bio )chemical… …   Wikipedia

  • Activation — Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom. Activation peut faire référence à : en physique nucléaire (au contraire de la contamination qui n est finalement qu un salissement de surface) décrit …   Wikipédia en Français

  • activation — See activate. * * * ▪ psychology also called  arousal        in psychology, the stimulation of the cerebral cortex into a state of general wakefulness, or attention. Activation proceeds from various portions of the brain, but primarily from the… …   Universalium

  • activation — aktyvacija statusas T sritis Standartizacija ir metrologija apibrėžtis Akytųjų medžiagų apdorojimas, kad padidėtų jų gertis. atitikmenys: angl. activation vok. Aktivation, f; Aktivierung, f rus. активация, f; активирование, n pranc. activation, f …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • activation — aktyvacija statusas T sritis Standartizacija ir metrologija apibrėžtis Dirbtinių radioaktyviųjų izotopų gavimas stabilius atomų branduolius apšaudant neutronais, protonais, deuteronais, kitais branduoliais arba švitinant gama kvantais.… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • activation — aktyvacija statusas T sritis Standartizacija ir metrologija apibrėžtis Medžiagos žadinimas (kaitinimas, švitinimas, apdorojimas kt. medžiagomis), kad lengviau, sparčiau ir stipriau vyktų jos cheminis ar fizikinis kitimas. atitikmenys: angl.… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • activation — aktyvacija statusas T sritis Standartizacija ir metrologija apibrėžtis Molekulių sužadinimas; tokios molekulės lengviau reaguoja. atitikmenys: angl. activation vok. Aktivation, f; Aktivierung, f rus. активация, f; активирование, n pranc.… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas


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