Many clinically important or mechanistically interesting inhibitors react with enzymes by a branched pathway in which inactivation of the enzyme and formation of product are competing reactions. The steady-state kinetics for this pathway [Waley (1980) Biochem. J. 185, 771-773] gave equations for progress curves that were cumbersome. A convenient linear plot is now described. The time (t1/2) for...

There is little experimental knowledge on the sequence dependent rate of hairpin formation in RNA. We have therefore designed RNA sequences that can fold into either of two mutually exclusive hairpins and have determined the ratio of folding of the two conformations, using structure probing. This folding ratio reflects their respective folding rates. Changing one of the two loop sequences from ...

The Bi-2223 phase growth was studied on the view growth Kinetics and described by using suggested kinetic equations, and the kinetics parameters of the 2223 growth were experimentally determined. The precursor particle size effect on Bi-2223 phase growth was studied, as well. Precursors in this experiment were made by four different techniques with different particle sizes, and samples were sin...

in this work, experimental kinetics data of methane hydrate decomposition at temperatures ranging from 272.15 to 276.15 k and at pressures ranging from 10 to 30 bars were modeled by using chemical affinity. this model proposed a macroscopic model which is independent of any intermediate mechanism like heat or mass transfer. the results show there is good agreement with experimental data. also t...

Long-term parenteral nutrition (PN) can induce intestinal atrophy, leading to a loss of epithelial integrity in the small intestines. This change may alter the intestinal permeability of vancomycin (VCM), a non-absorbable antibiotic. The aim of the present study was to investigate the effect of PN on the pharmacokinetics of VCM in rats. VCM was intravenously (5 mg/kg) or intraduodenally (20 mg/...

We assessed pharmacokinetic and safety profiles of ceftazidime-avibactam administered ± metronidazole, and whether drug-drug interactions exist between ceftazidime and avibactam, or ceftazidime-avibactam and metronidazole. The first study (NCT01430910) involved two cohorts of healthy subjects. Cohort 1 received ceftazidime-avibactam (2000-500 mg) as a single infusion or as multiple intravenous ...

There is no randomized study carried out in order to compare their pharmacokinetic parameters although midazolam, as a sedative, has been widely administered via continuous infusion as well as intermittent bolus doses in mechanically ventilated critically ill patients. We prospectively investigated the effect of these two principal methods on pharmacokinetic parameters in 23 of mentioned patien...

Based on the widely accepted mathematical model of fermentation kinetics, an analytical solution is deduced in this paper. To describe the feature of batch fermentation, the parameters of the fermentation kinetics in the analytical solution (i.e., mumax, Ks, beta, YG, YP, and m) are estimated at one strike with POWELL optimization algorithm coded in FORTRAN-77. The experimental data in the exam...

A new model based on a combination of the polymeric multigrain and multilayer models has been developed to predict the polymerization rate, particle growth, morphology, effective parameters on broadening of the molecular weight distribution, number and weight average of the molecular weight, isotacticity index and bulk density of polymer. Mathematical correlations and the kinetics used in t...

CONTEXT There is a paucity of data describing the impact of type of beverage (coffee versus energy drink), different rates of consumption and different temperature of beverages on the pharmacokinetic disposition of caffeine. Additionally, there is concern that inordinately high levels of caffeine may result from the rapid consumption of cold energy drinks. OBJECTIVE The objective of this stud...