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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Pharmaceutical research 17 (2000), S. 38-41 
    ISSN: 1573-904X
    Schlagwort(e): absorption ; aerosols ; surface active agents ; drug administration routes ; drug formulation ; radioactive imaging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Purpose. Small solutes which are deposited in the alveoli by aerosolinhalation will be absorbed across the alveolo-capillary barrier.Inhalation of dioctyl sodium sulfosuccinate (DOSS) enhances absorptionwhile having little or no effect on lung function, suggesting that surfaceactive agents may be used as enhancers of alveolar absorption ofinhaled pharmaceuticals. The purpose of this study was to examinethe effects of a selection of different surface active agents onalveolar absorption. Methods. The absorption of 99mTc-diethylene triamine pentaacetate(99mTc-DTPA) from the lungs was studied in rabbits. We studied fivedifferent surface active agents: DOSS, sodium glycodioxycholate(GDCA), sodium lauryl sulphate (NaLS), lysophosphatidyl choline(LPC) and polyoxyethylene-23-laurylether (P23LE). Results. DOSS and GDCA both dramatically enhanced the absorptionof 99mTc-DTPA. There was a moderate effect of NaLS, no significanteffect of LPC and P23LE reduced the rate of absorption. None of thecompounds affected gas exchange or lung compliance. Conclusions. There is a wide spectrum of effects of inhaled surfaceactive agents on the alveolar absorption of 99mTc-DTPA. Ioniccompounds such as DOSS and GDCA have the greatest effect, and furtherstudies of these classes of surface active agents for use as enhancersof alveolar absorption of pharmaceuticals seem warranted.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1573-4943
    Schlagwort(e): Alkaline phosphatase ; inhibition ; chemical modification ; N-bromosuccinimide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The inactivation of alkaline phosphatase from green crab (Scylla serrata) by N-bromosuccinimide has been studied using the kinetic method of the substrate reaction during modification of enzyme activity previously described by Tsou [(1988),Adv. Enzymol. Related Areas Mol. Biol. 61, 381–436]. The results show that inactivation of the enzyme is a slow, reversible reaction. The microscopic rate constants for the reaction of the inactivator with free enzyme and the enzyme-substrate complex were determined. Comparison of these rate constants indicates that the presence of substrate offers marked protection of this enzyme against inactivation by N-bromosuccinimide. The above results suggest that the tryptophan residue is essential for activity and is situated at the active site of the enzyme.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 23 (1996), S. 19-27 
    ISSN: 0271-2091
    Schlagwort(e): turbulence ; channel flow ; low Reynolds number ; large-eddy simulation ; subgrid-scale model dynamic SGS model ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Maschinenbau
    Notizen: Several issues related to applications of the dynamic subgrid-scale (SGS) model in large-eddy simulation (LES) at low Reynolds number are investigated. A modified formulation of the dynamic model is constructed and its performance in low-Reynolds-number LES of channel flow is assessed through a comparison of length scales computed respectively by this modified model, the Germano-Lilly dynamic SGS model and two empirical wall damping functions with optimum model coefficients, which have been successfully used in many simulations of channel flows. Two values of the ratio of filter widths are set for each of the dynamic models. The results have confirmed that the modified dynamic SGS model gives the correct behaviour of the subgrid eddy viscosity in the region of a plane wall to an accuracy that exceeds the best-tuned wall damping function, and almost collapses with the theoretical behaviour of the length scale near the wall without any tuning and adjustment. In addition, the impact of the choice of the ratio of filter widths on the modified dynamic SGS model is found to be much less than with the Germano-Lilly model.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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