Appearance rate

Requiring that the disappearance rate from the donor be equal to the appearance rate in the receiver, it follows that... 

Because VD and Vfi were taken to be unequal for the general case, the disappearance rate constant (a(3) is not equal to the appearance rate constant (a P )- However, the rate constants become identical when the volumes of the compartments are also identical. 

The conditions for Eqs. (72) and (73) are that the disappearance rate must be equal to the appearance rate and there is insignificant binding and metabolism by the cell. These assumptions are satisfied by the steroids with the exception of testosterone and progesterone. Hence, Pe values of testosterone and progesterone based on appearance kinetics will be underestimated unless the enzyme system is saturated. 

Given the low permeability of the antioxidant across MDCK cell monolayers and its large membrane partition coefficient, efflux kinetic studies using drug-loaded cell monolayers cultured on plastic dishes could yield useful information when coupled with the following biophysical model. The steady-state flux of drug from the cell monolayer is equal to the appearance rate in the receiver solution ... 

The phrase rate of reaction means how fast is the reaction or the speed of the reaction. It can be measured as the formation (appearance) rates of products (e.g. collecting gaseous product in a syringe) or the consumption (disappearance) rates of reactants. 

Three reports of free radical decomposition kinetics have appeared. Rate coefficients for the unimolecular dissociation of the acetyl radical have been obtained as a function of temperature from 420 to 500 K, and pressure from 1 to 6 torr by monitoring the rate of decay of CH3CO produced by photolysis of 2-butanone or 2,4-pentanedione [125] ... 

The effects of type of vinyl monomer on the properties of copolymer fabrics are shown in Table VII. Two different fabric constructions, print cloth and twill, were used. After the copolymer fabrics were prepared, they were given the usual treatment with dimethyloldihydroxyethylene urea to crosslink the cellulose. The wash-wear appearance ratings, flat abrasion resistances, and, in most cases, wrinkle-recovery angles of copolymer twill fabrics were improved over fabric controls. For copolymer... 

Figure 19.7 Pharmacokinetic model for analyzing drug disposition following direct intratumoral injection. ku rate constant of transfer from poorly perfused region to well perfused region k2, venous appearance rate constant k2, rate constant of leakage from the surface A, and X2, drug amounts in well perfused and poorly perfused regions, respectively.

The plasma appearance rate of both T, and rT3 in healthy humans amounts to approximately 40-45 nmol/day, which is roughly 5 (T3) and 20 (rT3) times the thyroidal secretion rates of these compounds [2,3], Consequently, 80% of circulating... 

For the reaction rates of Equations 14 to 17 global expressions from the literature were adopted. For reactions 14, 16, and 17, the overall correlations of Dryer and Glassman (1) were used, expressing respectively the methane disappearance" rate, the rate of reaction of carbon monoxide with oxygen in the presence of water, and the appearance rate of carbon dioxide in the methane-oxygen reaction ... 

Plot the cumulative amount versus time and use the linear portion of the plot to determine the appearance rate (Ag/Af, in mmol/s) according to the following equation ... 

Numerous papers dealing with the photoreduction of viologens have appeared. Rate constants for electron transfer between aromatic hydrocarbon triplets and bipyridinium and pyridinium salts have been measured. The results suggest that the process is both facile and efficient. All the rate constants necessary for the determination of the quantum yield of formation of the viologen cation-radical in the methyl viologen-Eosin-EDTA system are also now available. " The high activity of dihydroxytin(rv) uroporphyrin in the photoreduction of methyl viologen has been ascribed to the failure of a photochemi-cally inactive tt—tt complex to be formed between substrate and sensitizer. 

Turbidity of the oil is caused by its crystallization. The effects of 0.0, 0.50, and 1.0% DK F-lO addition and temperature on the appearance of full turbidity (nontransparent) are shown in Table 3. The turbidity appearance rate increased with increasing DK F-10 concentration in the oil. The differences in the rate are high at a higher temperature, i.e, 25°C and reduced at a lower temperature. Consequently, the addition of DK F-10 will allow the oil to temper at a relatively high temperature (around 25°C) will be more useful and effective in saving time and energy than that at a low temperature (around 12°C). 

Lancaster AK, Bardill JP, True HL, Masel J (2010) The spontaneous appearance rate of the yeast prion [PSf1 ] and its implications for the evolution of the evolvability properties of the PSI+] system. Genetics 184 393-400... 

Fig. 13. The relationship between the appearance rate of newly synthesized cholesterol in mesenteric lymph and the rate of hepatic cholesterol synthesis in the same animal. These studies were carried out as described in the legend to Fig. 12 but contained an additional group of animals that were fed different amounts of cholesterol to alter rates of hepatic cholesterol synthesis.

Figure 7.16 Energy level diagram for the NCNO NC + NO dissociation including the scheme for monitoring the NCNO decay rate and the product NO appearance rate (which were shown to be equal). Taken with permission from Khundkar et al. (1987).

We consider how to express reaction rates and how reactant disappearance rates and product appearance rates are related to the reaction stoichiometry. 

The possibility of comparing disappearance rate constants of reactant ions with appearance rate constants of product ions offers obvious advantages for the characterization of reaction pathways. In general, however, the task of collecting useful rate data is harder at high pressures than at low pressure, since additional complications arise. Additional assumptions are also necessary, for example, that it is valid to plot the normalized mass spectrum as a function of pressure. Surprisingly, perhaps, in view of what has been said about the uncertainty of detection efficiencies, this particular procedure seems to work rather well. ... 

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