| PPGB | protective protein of beta-galactosidase |
|---|---|
| ROPS | rollover protective structure |
| TCPD50 | 50% tissue culture protective dose |
| ALARM | adjustable leg and ankle repositioning mechanism |
| AM | Academic Medicine [journal]; actomyosin; acute myelofibrosis; adult male; adult monocyte; aerospace ... |
| PD50 | Protective dose |
|---|---|
| PI | Protective index |
| PPCA | Protective protein/cathepsin A |
| ROPS | Roll-over protective structures |
impedence test
| eye protective devices | Personal devices for protection of the eyes from impact, flying objects, glare, liquids, or injurious radiation. (12 Dec 1998) |
|---|---|
| association mechanism | The cerebral mechanism whereby the memory of past sensations may be compared or associated with present ones. (05 Mar 2000) |
| biochemical mechanism | This is the general term for any chemical reaction or series of reactions, usually mediated by enzymes, which produce a given physiological effect in a living organism. (09 Oct 1997) |
| Cairns mechanism | <molecular biology> A mechanism for the replication of a double stranded circular DNA molecule. Replication is initiated at a fixed point and proceeds either uni or bi directionally. (18 Nov 1997) |
| gating mechanism | Occurrence of the maximum refractory period among cardiac conducting cells approximately 2 mm proximal to the terminal Purkinje fibres in the ventricular muscle, beyond which the refractory period is shortened through a sequence of Purkinje cells, transitional cells, and muscular cells; gating mechanism may be a cause of ventricular aberration, bidirectional tachycardia, and concealed extrasystoles, a mechanism by which painful impulses may be blocked from entering the spinal cord. Compare: gate-control theory. (05 Mar 2000) |
| random mechanism | A scheme for substrate binding and product release for a multisubstrate enzyme; for a two-substrate two-product enzyme with this mechanism, either substrate can bind first and, after the reaction has taken place, either product can be the first to dissociate from the enzyme. Brain hexokinase has a random mechanism. More complex random mechanisms exist for enzymes having more than two substrates. (05 Mar 2000) |
| cassette mechanism | <molecular biology> Term used for genes such as the a and _ genes that determine mating type in yeast, either one or the other is active. In this gene conversion process, a double stranded nuclease makes a cut at a specific point in the MAT locus, the old gene is replaced with a copy of a silent gene from one or other flanking region and the new copy becomes active. As the process involves replacing one ready made construct with another in an active slot it is called a cassette mechanism. (18 Nov 1997) |
| re-entrant mechanism | The probable basis of most arrhythmias, requiring at least three criteria in the heart: 1. A loop circuit, 2. Unidirectional block, 3. Slowed conduction. Impulses enter the loop circuit and divide in both directions (blocked in one direction only), negotiate the loop circuit to the area of block where the slowed conduction has allowed the impulse to arrive at a time when the tissue proximal to the unidirectional block has recovered and will permit its passage in the opposite direction. (05 Mar 2000) |
| mechanism | The manner of combination of parts, processes, etc., which subserve a common function. Origin: Gr. Mechan = machine (18 Nov 1997) |
| mechanism-based inhibitor | A competitive inhibitor that is converted to an irreversible inhibitor at the active site of the enzyme. Synonym: mechanism-based inhibitor. (05 Mar 2000) |
| rolling circle mechanism | <molecular biology> A mechanism of DNA replication in many viral DNAs, in bacterial f factors during mating and of certain DNAs in gene amplification in eukaryotes. DNA synthesis starts with a cut in the + strand at the replication origin, the 5' end rolls out and replication starts at the 3' side of the cut around the intact circular DNA strand. Replication of the 5' end (tail) takes place by the formation of Okazaki fragments. (18 Nov 1997) |
| ping-pong mechanism | A special multisubstrate reaction in which, for a two-substrate, two-product (i.e., bi-bi) system, an enzyme reacts with one substrate to form a product and a modified enzyme, the latter then reacting with a second substrate to form a second, final product, and regenerating the original enzyme. An example of such a mechanism is found in the aminotransferases. More complex ping-pong mechanisms exist for enzymes having more than two substrates. Synonym: double displacement mechanism. (05 Mar 2000) |
| countercurrent mechanism | A system in the renal medulla that facilitates concentration of the urine as it passes through the renal tubules. See: countercurrent exchanger, countercurrent multiplier. (05 Mar 2000) |
| pressoreceptive mechanism | The pressoreceptor system, especially of the carotid sinuses and aortic arch. (05 Mar 2000) |
| proprioceptive mechanism | <physiology> The mechanism of sense of position and movement, by which muscular movements can be adjusted to a great degree of accuracy and equilibrium maintained. (05 Mar 2000) |