Average Adsorption Rate Research Articles

Adsorption of Vitamin K-dependent Proteins to Live Cell Membranes Measured under Flow Conditions

Mechanisms mediating initial adsorption of coagulation proteins to live cells were investigated. Adsorption kinetics were examined under varying flow conditions using tracer-dilution techniques in perfused spherical monolayers of cells expressing tissue factor. At biologically relevant time and concentration ranges, rates exceeded by 2-12 fold the theoretical maximum calculated for steady-state diffusion. Rates were correlated with aqueous-phase flux of reactants and were found to be largely independent of the density of reactive sites on the membrane. Average adsorption rate of factor VIIa at 4 etaM and flow velocity of 0.8 etam s(-1) was 5 x 10(7) s(-1) cm(-2). Adsorption rates of homologous coagulation factors IX and X under similar conditions were 5 and 9 x 10(7) s(-1)cm(-2). Results indicate that flow can effectively increase the rate of coagulation factor adsorption to the membrane of live cells. They also imply that factors affecting blood flow velocity and vessel permeability influence the rate of membrane-dependent coagulation reactions.

Adsorption Characteristics of LaNi5Particles

Nitrogen adsorption on an intermetallic compound, LaNi5, was studied before and after activation and after hydriding–dehydriding cycling. The specific surface area of activated LaNi5was 0.271±0.004 m2g−1. Adsorption and desorption isotherms of activated LaNi5were obtained. The adsorption isotherm was similar to type II among the five types of isotherms classified by S. Brunauer, L. S. Deming, W S. Deming, and E. Teller (J. Am. Chem. Soc.62, 1723, 1940). Its hysteresis curve had the type B form among de Boer’s five types of hysteresis. Desorption pore-size analyses showed that the activated LaNi5had only a few mesopores, the diameters of which were around 20–110 Å. The average adsorption rate of the activated LaNi5showed a first-order dependence on nitrogen pressure at 77 K.

The isolation and characterization of a lipopolysaccharide-specific Pseudomonas aeruginosa bacteriophage.

The isolation and some properties of a lipopolysaccharide (LPS)-specific phage isolated against Pseudomonas aeruginosa is reported. The phage, designtaed omega PLS-I, is a Bradley A type phage with a head diameter of 70 nm and a contractile tail 120 nm long. The average adsorption rate constant for omegaPLS-I is 4-48 X 10(-9) ml/min. omegaPLS-I is inactivated by purified LPS from P. aeruginosa strain 1-1A, showing a PhI50 value of 1-25 mug/ml.

Isolation of a polyvalent bacteriophage for Escherichia coli, Klebsiella pneumoniae, and Aerobacter aerogenes.

A lytic bacteriophage isolated from sewage was found to attack strains of Aerobacter aerogenes, Escherichia coli, and Klebsiella pneumoniae, but not members of the genera Salmonella, Proteus, and Serratia. The phage, designated phimp, contained deoxyribonucleic acid with a 50% guanine plus cytosine ratio and a molecular weight of 23.1 x 10(6) daltons. Single-step growth experiments of phimp plated at 37 C on A. aerogenes A2 gave a mean latent period of 20 min, an average burst size of 103 plaque-forming units/infected cell, and an average adsorption rate constant of 3 x 10(-10) ml/min. Electron microscopy of phimp revealed a phage with a flexible tail (165 nm long and 6 nm wide). The phage head had a hexagonal outline (62 nm in diameter).