| depolarisation | The process or act of neutralising polarity, depriving of polarity, or the result of such action; reduction to an unpolarised condition. <physiology> The reversal of the resting potential in excitable cell membranes when stimulated i.e., the tendency of the cell membrane potential to become positive with respect to the potential outside the cell. A positive shift in a cells resting potential (that is normally negative), thus making it numerically smaller and less polarized, for example 90mV to 50mV. <optics> Depolarisation of light, a change in the plane of polarization of rays, especially by a crystalline medium, such that the light which had been extinguished by the analyser reappears as if the polarization had been anulled. The word is inappropriate, as the ray does not return to the unpolarised condition. Origin: Cf. F. Depolarisation. (27 Oct 1998) |
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| depolarise | 1. <optics> To deprive of polarity; to reduce to an unpolarised condition. This word has been inaccurately applied in optics to describe the effect of a polarising medium, as a crystalline plate, in causing the reappearance of a ray, in consequence of a change in its plane of polarisation, which previously to the change was intercepted by the analyser. 2. <physics> To free from polarisation, as the negative plate of the voltaic battery. Origin: F. Depolariser. Source: Websters Dictionary (01 Mar 1998) |
| depolariser | <physics> A substance used to prevent polarisation, as upon the negative plate of a voltaic battery. Source: Websters Dictionary (01 Mar 1998) |
| depolarising block | <physiology> Skeletal muscle paralysis associated with loss of polarity of the motor endplate, as occurs following administration of succinylcholine. (05 Mar 2000) |
| depolarising relaxant | <pharmacology, physiology> An agent, e.g., succinylcholine, that induces depolarisation of the motor endplate and so paralyzes skeletal muscle by a phase I block. (05 Mar 2000) |
| depolymerase | <biochemistry> Name used originally, before hydrolytic action was understood, for an enzyme catalyzing the hydrolysis of a macromolecule to simpler components. See: nuclease. (05 Mar 2000) |
| depolymerisation | <biochemistry> The dismantling of a polymer (a chain of monomer units) into individual monomers. (09 Oct 1997) |
| depopulation | <veterinary> Humane destruction of all animals on a premises during a disease eradication program. Used primarily in national programs established to eradicate newly introduced diseases (e.g., foot-and-mouth disease) that pose serious economic threats to the livestock industries. (05 Mar 2000) |
| deposit | 1. That is deposited, or laid or thrown down; as, a deposit in a flue; especially, matter precipitated from a solution (as the siliceous deposits of hot springs), or that which is mechanically deposited (as the mud, gravel, etc, deposits of a river). "The deposit already formed affording to the succeeding portion of the charged fluid a basis." (Kirwan) 2. <chemical> A natural occurrence of a useful mineral under the conditions to invite exploitation. 3. That which is placed anywhere, or in any one's hands, for safe keeping; somthing intrusted to the care of another; especially, money lodged with a bank or banker, subject to order; anything given as pledge or security. 4. A bailment of money or goods to be kept gratuitously for the bailor. Money lodged with a party as earnest or security for the performance of a duty assumed by the person depositing. 5. A place of deposit; a depository. Bank of deposit. See Bank. In deposit, or On deposit, in trust or safe keeping as a deposit; as, coins were recieved on deposit. Origin: L. Depositum, fr. Depositus, p. P. Of deponere: cf. F. Depot, OF. Depost. See Deposit, and cf. Depot. Source: Websters Dictionary (01 Mar 1998) |
| depot injection | An injection of a substance in a vehicle that tends to keep it at the site of injection so that absorption occurs over a prolonged period. (05 Mar 2000) |
| depot reaction | Reddening of the skin at the point where the needle entered, in the subcutaneous tuberculin test. (05 Mar 2000) |
| depot therapy | Injection of a drug together with a substance that slows the release and prolongs the action of the drug. (05 Mar 2000) |