| ADR | activation, depression, repetition [in bone remodeling]; adrenodoxin reductase; Adriamycin; adverse ... |
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| AE | above-elbow [amputation]; acrodermatitis enteropathica; activation energy; adult erythrocyte; advers... |
| AECD | allergic eczematous contact dermatitis |
| ARAM | antigen recognition activation motif |
| CD | cadaver donor; canine distemper; canine dose; carbohydrate dehydratase; carbon dioxide; cardiac dise... |
| trans-activation (genetics) | Increased rate of gene expression directed by either viral or cellular proteins. These regulatory factors (diffusible gene products) act in trans -- that is, act on homologous or heterologous molecules of DNA. (cis-acting factors act only on homologous molecules.) (12 Dec 1998) |
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| energy of activation | Energy that must be added to that already possessed by a molecule or molecules in order to initiate a reaction; usually expressed in the Arrhenius equation relating a rate constant to absolute temperature. (05 Mar 2000) |
| enzyme activation | Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1) activation by ions (activators); 2) activation by cofactors (coenzymes); and 3) conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme. (12 Dec 1998) |
| juxtacrine activation | Activation of target cells by membrane anchored growth factors, also used for activation of leucocytes by PAF bound to endothelial cell surface. (18 Nov 1997) |
| feedback activation | The activation of an enzyme by an end product of a biochemical pathway in which that enzyme plays a part. For example, the activation of factors VIII and V by thrombin during blood clotting. (05 Mar 2000) |
| feed-forward activation | The activation of an enzyme by a precursor of the substrate of that enzyme. (05 Mar 2000) |
| upstream activation site | A DNA sequence that regulates transcription like an enhancer but does notwork if its located downstream from a promoter. (09 Oct 1997) |
| low-activation materials | <radiobiology> In fission reactors, one is forced to deal with the radioactive byproducts of the fission process, but in fusion reactors one generally has a choice of what materials to expose to neutrons produced by the fusion process. A major problem for fusion reactors is developing materials (such as for the reactor vacuum vessel structure) which can be exposed to high levels of neutron bombardment without becoming permanently radioactive. Candidate structural materials which have relatively low induced radiactivation (generally relative to stainless steel) are known as low-activation materials, these include titanium, vanadium, and silicon-carbide. (09 Oct 1997) |
| lymphocyte activation | <haematology> The change in morphology and behaviour of lymphocytes exposed to a mitogen or to an antigen to which they have been primed. The result is the production of lymphoblasts, cells that are actively engaged in protein synthesis and that divide to form effector populations. Should not be confused with transformation of the type associated with oncogenic viruses and activation is therefore perhaps a better term. (18 Nov 1997) |
| allergic contact dermatitis | A delayed type IV allergic reaction of the skin with varying degrees of erythema, oedema, and vesiculation resulting from cutaneous contact with a specific allergen. Synonym: contact allergy. (05 Mar 2000) |
| balancing contact | The contact's between upper and lower dentures on the balancing or mediotrusive side for the purpose of stabilizing the dentures, the contact's between upper and lower dentures at the opposite side from the working or laterotrusive side (anteroposteriorly or laterally) for the purpose of stabilizing the dentures, the contact's between upper and lower natural or artificial teeth at the opposite side from the working or laterotrusive side. Synonym: balancing occlusal surface. (05 Mar 2000) |
| centric contact | The relation of opposing occlusal surfaces which provides the maximum planned contact and/or intercuspation, the occlusion of the teeth when the mandible is in centric relation to the maxillae. Synonym: centric contact. (05 Mar 2000) |
| microradiography, contact | <microscopy> A method of making micrographs by means of X-rays. The specimen is placed close to a fine-grained photographic emulsion at some distance from the X-ray source. The X rays pass through the specimen and the differential absorption and the scattering of the radiation is recorded by the emulsion. The resulting negative is examined and photographed through a light microscope. (05 Aug 1998) |
| close contact infection | <epidemiology> An infection which requires close contact, other than sexual contact, between susceptible and infectious individuals, for transmission. (05 Dec 1998) |
| contact | A mutual touching of two bodies or persons. Origin: L. Contactus = a touching together (18 Nov 1997) |