(n.) The act of extinguishing or making extinct; a putting an end to; the act of putting out or destroying light, fire, life, activity, influence, etc.
(n.) State of being extinguished or of ceasing to be; destruction; suppression; as, the extinction of life, of a family, of a quarrel, of claim.
Example Sentences:
(1) The stages of mourning involve cognitive learning of the reality of the loss; behaviours associated with mourning, such as searching, embody unlearning by extinction; finally, physiological concomitants of grief may influence unlearning by direct effects on neurotransmitters or neurohormones, such as cortisol, ACTH, or norepinephrine.
(2) The effect upon ethanol responding was found not to resemble a pattern of extinction, but rather was best described as a general overall reduction in responding.
(3) In a recent study, Orr and Lanzetta (1984) showed that the excitatory properties of fear facial expressions previously described (Lanzetta & Orr, 1981; Orr & Lanzetta, 1980) do not depend on associative mechanisms; even in the absence of reinforcement, fear faces intensify the emotional reaction to a previously conditioned stimulus and disrupt extinction of an acquired fear response.
(4) We conclude that the procedure used in this study is a non-intrusive intervention that is an extension of the current literature pertaining to sensory extinction.
(5) After 40 programmed minutes of acquisition and 12 min of maintenance, without notice, both schedules changed to extinction for 28 min.
(6) This differential absorbance is linear with increasing concentrations of Na2MoO4 and was used to calculate the molar extinction coefficient of molybdochelin at 425 nm (epsilon similar to 6,200).
(7) However, during massed testing, all subjects trained with response contingent CS termination showed an overall extinction influence, which was most pronounced in the medial subgroup, although the laterals showed frequency control as well.
(8) When reinforcement for competing behavior was withdrawn, however, rats resumed their original behavior and there were no overall savings in total responses to extinction.
(9) The relative amount of the crystals was measured in both amoeba strains on the basis of the integral extinction value.
(10) Chronic extinction of chain closed conditioned reflex in intact rabbits took five to six days.
(11) The amounts of phosphatidylcholine and sphingomyelin could be determined by high-performance liquid chromatography and ultraviolet absorption if the apparent extinction coefficient of the material analyzed was established.
(12) In a number of neurones the extinction of reflexes either does not change the reaction to acetylcholine, or enhances it.
(13) In Experiment 3, following an unsignaled reinforcement delay, groups receiving either no event or signaled food in the context responded faster in extinction than groups receiving no context exposure or unsignaled food.
(14) The optical extinction decreases as the red cell agglutinates grow, giving a parametric estimate of the haemagglutination rate.
(15) By calculating for DNA standard solutions the value of the ratio between the extinction at 665 nm after 15 min to the extinction of 600 nm after 2 min of the orcinol reaction it is possible to increase specifiaty of the orcinol method for determination of the RNA content.
(16) To lose the Sundarbans would be to move a step closer to the extinction of these majestic animals," said ZSL tiger expert Sarah Christie.
(17) Values obtained for thebuoyant density, isoelectric point, and extinction coefficient differed minimally; major differences were observed in the molecular weight and the characterisitc width of cylinders formed by in vitro-assembled T-layer of the wild-type and variant.
(18) The CS+ preference persisted for several weeks during extinction tests when both the CS+ and CS- were paired with IG water or with no infusions.
(19) The extinction coefficient at 550 nm for the oxidized enzyme is about 5300 (M subunit)-1 X cm-1.
(20) On this planet, extinction is the norm – of the 4 billion species ever thought to have evolved, 99% have become extinct.
Quenching
Definition:
(p. pr. & vb. n.) of Quench
Example Sentences:
(1) The extreme quenching of the dioxetane chemiluminescence by both microsomes and phosphatidylcholine, as a model phospholipid, implies that despite the low quantum yield (approx.
(2) The drug is extracted from serum or urine with ethyl acetate, separated by TLC, and determined by fluorescence quenching densitometry.
(3) Formation of a complex between alpha-tocopherol or its analogues in the excited state and fatty acids or their hydroperoxides has been suggested basing on the fluorescence quenching experimental data.
(4) Quenching of intrinsic fluorescence of (Ca2+-Mg2+)-ATPase by acrylamide, performed in the presence of Ca2+, gave evidence for a single class of tryptophan residues with Stern-Volmer constant (KSV) of 10 M-1.
(5) The 23Na double-quantum signal was quenched in both the extracellular and the intracellular compartments with increasing concentration of Li in each compartment, along with an increase in the 23Na T1 both intra- and extracellularly.
(6) Binding increases the fluorescence intensity of Tyr-49 by 130% while the fluorescence of the hormone tyrosine is almost completely quenched.
(7) Addition of 2,6-dimethylbenzoquinone caused quenching of these absorbance changes.
(8) These observations lead to the hypothesis that acidosis quenches fluorescence in distal skin flaps.
(9) The degree of quenching was accurately predicted by a simple relation derived in this paper, as well as a more complex equation previously developed by Tweet, et al.
(10) Subtilin may slightly enter the hydrophobic core as suggested by tryptophan fluorescence quenching and liposome fusion experiments.
(11) Greater than 99% of the polymerization reaction products were quenched by the addition of 2.0 mM ascorbate.
(12) Acoustic probe-based assays can enhance assay and laboratory efficiency through testing for multiple analytes in a single sample or increasing available binding surface area (by using probe and well surfaces simultaneously), and by eliminating quenching.
(13) The second-order rate constants appear to be at least 3 orders of magnitude lower than the second-order constants for quenching of the fluorescent probes; this is taken as a clear indication that ubiquinone diffusion is not the rate-determining step in the quinone-enzyme interaction.
(14) Accessibility to iodide was much lower, as was the rate of quenching by iodide, adding support to the conclusions from acrylamide quenching.
(15) An ATP-dependent, N-ethylmaleimide-inhibitable, 3,3',4',5-tetrachlorosalicylanilide-reversible, and chloride-attenuated quench of bis(1,3-dibutylbarbituric acid-(5] pentamethinoxonol fluorescence was seen, consistent with net transfer of positive charge into the vesicles.
(16) Quenching data indicated that five out of 22 tryptophans in CBH are surface-localized and are available for quenching with both KI and acrylamide, and three other tryptophans are buried and are available only to acrylamide.
(17) Acid quenching of a stiochiometric reaction between Ac(= S)CoA and citrate synthase following the transient quantitatively regenerates Ac(= S)CoA, indicating carbon-carbon bond formation had not yet occurred.
(18) The pulsed laser photolysis products of the charge-transfer quenching reaction were examined.
(19) The highest yield of amino acids with the quench reaction was 9 x 10-7 molecules per erg of input energy.
(20) Tris-washed chloroplast enriched in the photosystem II reaction center species Z+Q- and ZQ- are nearly four times more sensitive to nitrobenzene quenching than those enriched in Z+Q.