Effect of Protein Adsorption and Ionic Strength on the Equilibrium Partition Coefficient of Ionizable Macromolecules in Charged Nanopores

2004 ◽  
Vol 108 (45) ◽  
pp. 17660-17665 ◽  
Author(s):  
P. Maarten Biesheuvel ◽  
Pieter Stroeve ◽  
Peter A. Barneveld
Keyword(s):  
Ionic Strength ◽  
Partition Coefficient ◽  
Protein Adsorption ◽  
Equilibrium Partition ◽  
Equilibrium Partition Coefficient

Solute Trapping in Metals

1992 ◽  
Vol 279 ◽  
Author(s):  
Patrick M. Smith ◽  
Riccardo Reitanot ◽  
Michael J. Aziz
Keyword(s):  
Partition Coefficient ◽  
Growth Model ◽  
Solidification Velocity ◽  
Continuous Growth ◽  
Solute Trapping ◽  
Solute Partitioning ◽  
Equilibrium Partition ◽  
Conductance Technique ◽  
Equilibrium Partition Coefficient ◽  
Alloy Properties

ABSTRACTMany of the advances in rapid solidification processing of metallic alloys exploit the trapping of solute which occurs at high solidification velocities. The difficulty of performing experiments which measure such high solidification velocities in metals has until now prevented accurate measurements of solute trapping in these systems. We have observed the transition from near-equilibrium solute partitioning to solute trapping during solidification at m/s velocities in aluminum alloys, and have compared the predictions of various solute trapping models. Aluminum thin films deposited on insulators were ion-implanted with Sn, Cu, Ge, and In, and were pulsed-laser melted; plane-front solidification was achieved, and regrowth velocities of 0.6 m/s to 5 m/s were measured with the transient conductance technique. Of the existing solute trapping models, the Continuous Growth Model of Aziz was found to fit the observed dependence of the partition coefficient on solidification velocity more closely than any other single-parameter model. The diffusive speed, which locates the transition from solute partitioning to solute trapping, was found to vary from 6 m/s to 38 m/s for various solutes in aluminum. We have examined correlations between the diffusive speed in the Continuous Growth Model and known alloy properties in order to allow better estimates of the diffusive speed to be made for alloy systems in which it has not been measured; the relation between the diffusive speed and the equilibrium partition coefficient will be discussed.

scholarly journals Orientation and Velocity Dependence of the Nonequilibrium Partition Coefficient

1995 ◽  
Vol 398 ◽  
Author(s):  
K.M. Beatty ◽  
K.A. Jackson
Keyword(s):  
Monte Carlo ◽  
Diffusion Coefficient ◽  
Partition Coefficient ◽  
Interface Velocity ◽  
Velocity Dependence ◽  
Step Velocity ◽  
Equilibrium Partition ◽  
Equilibrium Partition Coefficient ◽  
Solid Liquid Interface ◽  
Solid Liquid

ABSTRACTMonte Carlo simulations based on a Spin-1 Ising Model for binary alloys have been used to investigate the non-equilibrium partition coefficient (kneq ) as a function of solid-liquid interface velocity and orientation. In simulations of Si with a second component kneq is greater in the [111] direction than the [100] direction in agreement with experimental results reported by Aziz et al. The simulated partition coefficient scales with the square of the step velocity divided by the diffusion coefficient of the secondary component in the liquid.

scholarly journals Adsorption of amyloglucosidase from Aspergillus niger NRRL 3122 using ion exchange resin

2008 ◽  
Vol 51 (5) ◽  
pp. 1015-1024 ◽  
Author(s):  
Ana Paula Manera ◽  
Eliana Setsuko Kamimura ◽  
Luciana Machado Brites ◽  
Susana Juliano Kalil
Keyword(s):  
Aspergillus Niger ◽  
Partition Coefficient ◽  
Partition Coefficients ◽  
Deae Cellulose ◽  
Ion Exchange Resin ◽  
Least Square ◽  
Optimum Conditions ◽  
Equilibrium Partition ◽  
Equilibrium Partition Coefficient ◽  
Least Square Procedure

Amyloglucosidase enzyme was produced by Aspergillus niger NRRL 3122 from solid-state fermentation, using deffated rice bran as substrate. The effects of process parameters (pH, temperature) in the equilibrium partition coefficient for the system amyloglucosidase - resin DEAE-cellulose were investigated, aiming at obtaining the optimum conditions for a subsequent purification process. The highest partition coefficients were obtained using 0.025M Tris-HCl buffer, pH 8.0 and 25ºC. The conditions that supplied the highest partition coefficient were specified, the isotherm that better described the amyloglucosidase process of adsorption obtained. It was observed that the adsorption could be well described by Langmuir equation and the values of Qm and Kd estimated at 133.0 U mL-1 and 15.4 U mL-1, respectively. From the adjustment of the kinetic curves using the fourth-order Runge-Kutta algorithm, the adsorption (k1) and desorption (k2) constants were obtained through optimization by the least square procedure, and the values calculated were 2.4x10-3 mL U-1 min-1 for k1 and 0.037 min-1 for k2 .

Apparent octanol/water partition coefficients of pentachlorophenol as a function of pH

1982 ◽  
Vol 60 (16) ◽  
pp. 2104-2106 ◽  
Author(s):  
Klaus L. E. Kaiser ◽  
Ilze Valdmanis
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Partition Coefficient ◽  
Linear Function ◽  
Partition Coefficients ◽  
Extreme Values ◽  
Log P ◽  
Water Partition Coefficient ◽  
Non Linear ◽  
Good Agreement

The apparent 1-octanol/water partition coefficient (log PApp) of pentachlorophenol (PCP) varies in non-linear function with pH of the aqueous solution. In the range of pH 1.2 to 13.5 extreme values of log PApp 4.84 at pH 1.2 and log PApp 1.3 at pH 10.5 were observed. In the alkaline regime, log PApp increases strongly with the ionic strength. The ion-corrected partition coefficient of PCP was found to be log P 5.05 in good agreement with literature values.

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