Reversion spontaneous

Zinc not only provides protection, but can gradually reverse spontaneous inactivation, as illustrated in Fig. 5. The enzyme was incubated at 37°, and zinc sulfate was added after 3 hours to cause a progressive recovery of activity. The slow reactivation is in contrast to the instantaneous effect of Zn2+ on an EDTA-treated, enzyme preparation. In a preparation that had lost activity during storage without the addition of Zn2+, the gradual increase in activity on incubation with Zn2+ frequently led to a value greater than that of the unincubated control. 

Reversed spontaneous alternation deficits induced by scopolamine in the mouse. 113... 

Further, the fifth term on the righthand side of Eq. (5.23) describes reverse spontaneous transitions at the rate T j>j . In the analysis of reverse spontaneous transitions we make use of the fact that we have, as shown in [104],... 

The penultimate term in (5.92) deals with reverse spontaneous transitions. The function T jt j"(0, p 0, p ) represents the probability of the molecule with angular momentum orientation 3 (0, tp ) in the excited state arriving with orientation Ja(0, p) at the ground state. 

Reverse spontaneous transitions cannot change the orientation of the angular momentum of the molecule, hence we have Tjijn(0, p 0, p ) = Tj j"(0,p). Since the probability of spontaneous transition is invariant with respect to turn of coordinates, we may make an even stronger assertion Tj>j (0,p) = rjijn = const. According to the aforesaid we obtain a term that is responsible for reverse spontaneous transitions in the form Tj j bpQ KK Qq, which has to be added to the righthand side of Eq. (5.94). 

Generally, priapism reverses spontaneously, while penile blood flow and other signs being monitored, but in urgent cases, local phenylephrine injections or even surgery may be indicated... 

The only published study on presynaptlc effects of the more potent ChE inhibitors is that of Abraham and Edery (49), who examined the effect of soman on synaptic transmission in rat diaphragm. In vitro, soman increased the frequency of MEPPs (an effect blocked by Mg ), caused muscle depolarization that reversed spontaneously, and Increased quantal content. It was suggested that the observed changes in transmitter release resulted from an effect on the action potential invading the nerve terminal, although no direct evidence was offered. 

Asthma is a chronic inflammation disorder of the airways that make the bronchial tubes swell and narrow, producing wheezing, chest tightness, breathlessness, and coughing symptoms. Airway narrowing in asthma is caused by inflammation, bronchospasm, and bronchial hyperactivity. Asthma does not affect the alveoli and is reversible spontaneously and by drug treatment. Asthma is fully reversible and thus is different from COPD and emphysema, which are accompanied by destruction of alveolar walls and are irreversible. 

Before stating the second law, other attempts to reverse spontaneous processes will be considered. When a bar of metal, which was originally hotter at one end, has attained a uniform temperature, the initial state... 

It has long been realized that the impossibility, or rather the improbability, of reversing spontaneous processes is based on the inability to deal with individual molecules or small groups of molecules. If a device were available which could distinguish between fast- ( hot O slow-moving ( cold ) molecules, it would be possible to produce spontaneously a temperature gradient in a gas. Similarly, if a device could discriminate between two different types of gas molecules, a partial unmixing, which is the reverse of diffusion, could be achieved. However, the fact that no such devices are known is in accordance with the second law of thermodynamics. 

Polyuria uniformly accompanies cisplatin administration and occurs in two distinct phases. During the first 24-48 hours after administration, urine osmolality falls but glomerular filtration rate remains stable. This early polymia usually reverses spontaneously. The second phase occurs between 72 and % hours after cisplatin and is characterized by an increased urine volume with reduced osmolality. This later phase is accompanied by a persistent reduction in glomerular filtration... 

Rheology is concerned with the flow and/or deformation of matter under the influence of externally imposed mechanical forces. Two limiting types of behaviour arc possible. The deformation may reverse spontaneously (relax) when the external force is removed this is called elastic behaviour and is exhibited by rigid solids. The energy used in causing the deformation is stored, and then recovered when the solid relaxes. At the other extreme, matter flows and the flow ceases (but is not reversed) when the force is removed this is called viscous behaviour and is characteristic of simple liquids. The energy needed to maintain the flow is dissipated as heat. Between the two extremes arc systems whose response to an applied force depends on the lime-scale involved. Thus pitch behaves as an elastic solid if struck but flows if left for years on a slope. Similarly, a ball of Funny Putty , a form of silicone rubber, bounces when dropped on a hard surface, when the contact time is a few milliseconds, but flows if deformed slowly on a time-scale of seconds or minutes. Systems of this kind are said to be visco-elastic. The precise nature of the observable phenomena depends on the ratio of the time it takes for the system to relax to the time taken to make an observation. This ratio is called the Deborah number (De) ... 

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