Chloride transport by the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel is inhibited by a broad range of substances that bind within a wide inner vestibule in the pore and physically occlude Cl(-) permeation. Binding of many of these so-called open-channel blockers involves electrostatic interactions with a positively charged lysine residue (Lys95) located in the pore...

We combine high-resolution isotherms measurements and light scattering technics to study over a broad temperature range collective effects during the condensation and evaporation of helium from Vycor, a prototypic disordered porous material. For evaporation, our results provide the first direct evidence for a crossover from a percolation collective mechanism at low temperature to a local cavita...

Pore network modeling uses a network of pores connected by throats to model the void space of a porous medium and tries to predict its various characteristics during multiphase flow of various fluids. In most cases, a non-realistic regular lattice of pores is used to model the characteristics of a porous medium. Although some methodologies for extracting geologically realistic irregular net...

The mechanism of Cd2+ block of Ca2+ currents (ICa) was explored in squid neurons using whole-cell patch clamp. Control currents activated sigmoidally, more rapidly at more positive potentials, and did not inactivate significantly. External Cd2+ up to 250 microM reduced ICa reversibly. For small depolarizations, the current for a step of 10 ms increased to a maintained value, resembling the cont...

   In this study, linearized transport pore model (LTPM) is applied for modeling nanofiltration (NF) membrane separation process. This modeling approach is based on the modified extended Nernst-Planck equation enhanced by Debye-Huckel theory to take into account the variations of activity coefficient especially at high salt concentrations. Rejection of single-salt (NaCl) electrolyte is inve...

The effects of internal tetrabutylammonium (TBA) and tetrapentylammonium (TPeA) were studied on human cardiac sodium channels (hH1) expressed in a mammalian tsA201 cell line. Outward currents were measured at positive voltages using a reversed Na gradient. TBA and TPeA cause a concentration-dependent increase in the apparent rate of macroscopic Na current inactivation in response to step depola...

Objective(s): The structure- activity relationship of a series of 36 molecules, showing L-type calcium channel blocking was studied using a QSAR (quantitative structure–activity relationship) method. Materials and Methods: Structures were optimized by the semi-empirical AM1 quantum-chemical method which was also used to find structure-calcium channel blocking activity trends. Several types of ...

Faced with the bewildering characteristics of the ionic currents that cause the action potential in squid axon, Hodgkin and Huxley in 1952 developed an elegant model (1) that remains one of the most insightful descriptions of the functional properties of voltage-gated ion channels. One ingredient in this conceptual wizardry was the strict separation between gating, the process responsible for a...

in the present study, tin-promoted pd/mwnts nanocatalystwas synthesized via polyol technique for application in hydrogenation of high-concentrated acetylene feedstocks. tem images showed a restricted distribution of nanoparticles in the range of 3-5 nm. the results indicated that nanoparticles sizes were resistant to further catalyst deactivation. xrd patterns signified alloying between pd and ...

Porous materials are widely employed as supports in the immobilisation of enzymes. Traditionally macroporous materials with pore diameters >50 nm were believed to be the most suitable support material, ensuring no spatial restrictions upon enzyme molecules entering such large pores. In recent years however, there has been growing emphasis in the use of mesoporous supports with pore diameters ra...