Distribution kinetics

Industrial Engineering Chemistry Research 37, No.7, July 1998, p.2582-91 POLYETHYLENE PYROLYSIS THEORY AND EXPERIMENTS FOR MOLECULAR WEIGHT DISTRIBUTION KINETICS Sezgi N A Cha W S Smith J M McCoy B J California,University... 

Kawai R, Mathew D, Tanaka C, Rowland M Physiologically based pharmacokinetics of cyclosporine A extension to tissue distribution kinetics in rats and scale-up to human. J Pharmacol Exp Ther 1998 Nov 287(2) 457-68. 

Kelman BJ, Sikov MR. 1984. Transplacental movements of americium-241 in the guinea pig and early distribution kinetics in the dam. Teratology 29(2) 40A. 

Co2(CO)q system, reveals that the reactions proceed through mononuclear transition states and intermediates, many of which have established precedents. The major pathway requires neither radical intermediates nor free formaldehyde. The observed rate laws, product distributions, kinetic isotope effects, solvent effects, and thermochemical parameters are accounted for by the proposed mechanistic scheme. Significant support of the proposed scheme at every crucial step is provided by a new type of semi-empirical molecular-orbital calculation which is parameterized via known bond-dissociation energies. The results may serve as a starting point for more detailed calculations. Generalization to other transition-metal catalyzed systems is not yet possible. 

Recently Madras et al. [17], studying the degradation of styrene and poly(vinyl acetate) in chlorobenzene have analysed their data using a continuous distribution kinetics model. 

DIFFUSION OF LIGAND TO RECEPTOR Drug clearance, dosage, PHARMACOKINETICS Drug distribution kinetics, PHARMACOKINETICS Drug excretion rates,... 

Herman, R. A. and P. Veng-Pedersen. 1994. Quantitative structure-pharmacokinetic relationships for systemic drug distribution kinetics not con ned to a congeneric sefi harm. Sci83 423-428. 

Bagnasco M, Mariani G, Passalacqua G, Motta C, Bartolomei M, et al Absorbtion and distribution kinetics of the major Paritaria judaica allergen (Par j 1) administered by noninjectable routes in healthy humans beings. J Allergy Clin Immunol 1997 100 122-129. 

Yokogawa K, IshizakiJ, Ohkuma S, Miyamoto K. Influence of lipophilicity and lysosomal accumulation on tissue distribution kinetics of basic drags a physiologically based pharmacokinetic model. Methods Find Exp Clin Pharmacol. 2002 24 81-93. 

Collect intrinsic data pertaining to the emerging process liquid-liquid distribution, kinetics, hydrolytic and radiolytic stability, and the maximum metal loading in an organic phase without TPF, referred to as the limiting organic concentration (LOC). Consequently, build a database. 

Further to this, experiments strongly suggest that the more appropriate measure of true/tissue bioavailability is from the use of a SC AUC reference rather than from the use of an IV reference. The rationale for this change is based upon the nonlinear distribution kinetics of ASOs, and a further explanation is provided here. 

Carrier et al. (1995a) developed a model that describes the distribution kinetics of 2,3,7,8-TCDD and related chemicals (with chlorine substitutions in positions 2,3,7, and 8) in various mammalian species, including humans. Their model takes into account cellular diffusion, binding of the chemicals with the Ah receptor and with proteins, and enzyme induction in the liver. The model was used to describe the distribution of CDDs between liver and adipose tissue as a function of overall body concentration. 

Photophysical studies allow the measurement of rate constants for transmembrane electron transfer. The distributed kinetics observed in describing the decay of photovoltage across a BLM is consistent with a highly inhomogeneous disposition of donors and relays within the membrane [111, 112]. A typical value for the rate constant for electron transfer across a BLM (about 10 sec-1) would predict a spatial separation of about 10 A, whereas the thickness of the bilayer is usually about 40-50 A. This apparent discrepancy can be resolved if transmembrane electron transfer occurs by several sequential steps involving deeply buried redox sites, thus decreasing the operational tunnelling distance [113]. 

Balaz and Lukacova (1999) attempted to model the partitioning of 36 non-ionizable compounds in 7 tissues. Amphiphilic compounds, or those possessing extreme log Kow values, tended to show complex distribution kinetics because of their slow membrane transport. However for the non-amphiphilic, non-ionizable compounds with non-extreme log Kow values studied it should be possible to characterize their distribution characteristics based on tissue blood PCs. Distribution is dependent on membrane accumulation, protein binding, and distribution in the aqueous phase. As these features are global rather than dependent on specific 3D structure, distribution is not expected to be structure-specific. In this study, tissue compositions in terms of their protein, lipid, and water content were taken from published data. This information was used to generate models indicating that partitioning was a non-linear function of the compound s lipophilicity and the specific tissue composition. 

McCoy, B. Distribution kinetics for temperature-programmed pyrolysis. Industrial and Engineering Chemistry Research 1999 38 4531. 

M. Kuno, D. P. Fromm, S. T. Johnson, A. Gallagher, and D. J. Nesbitt, Modeling distributed kinetics in isolated semiconductor quantum dots. Phys. Rev. B 67 125304 (2003). 

Amir, A., Kadar, T., Chapman, S., Turetz, J., Levy, A., Babin, M., Ricketts, K., Brozetti, J., Logan, T., Ross, M. (2003). The distribution kinetics of topical C-sulfur mustard in rabbit ocular tissues and the effect of acetylcysteine. J. Toxicol. 22 201-14. 

The use of the differential mode of detector operation can be extremely useful in cases where the normal chromatographic development gives very poor separations due to poor distribution kinetics between the two phases. However, the technique does require significantly more sample for frontal analysis than for normal elution development so that sufficient sample must be available. Furthermore, the response of the detector operated in the differential mode is nearly two orders of magnitude less than that when used in the normal mode and so adequate detector sensitivity must be available. 

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