Silica nanopores are the focus of significant scientific interest due to their potential in a wide variety of applications including desalination membranes. In this paper, the results of extensive all-atom molecular dynamics simulations of the electro-osmotic flow of 0.5 M monovalent (NaCl) and divalent (CaCl(2)) ionic solutions through cylindrical charged silica nanopores are presented. The si...

Simplified, yet accurate, coarse-grained models are needed to explore the behavior of complex biological systems by means of Molecular Dynamics (MD) simulations, because many interesting processes occur at long time scales and large length scales that are not amenable to studies by atomistic simulations. The aqueous salt buffer provides an important contribution to the structure and function of...

The concentrations of sodium, potassium, chlorine, and phosphorus and the water content in A-band and I-band of rat heart muscle cells were measured by X-ray microanalysis. Concentrations per compartment water of both cations and anions are higher in the A-band, which is less hydrated than the I-band. It is concluded that at physiological ionic strength positive and negative fixed charges are e...

Opening of connexin hemichannels in the plasma membrane is highly regulated. Generally, depolarization and reduced extracellular Ca2+ promote hemichannel opening. Here we show that hemichannels formed of Cx50, a principal lens connexin, exhibit a novel form of regulation characterized by extraordinary sensitivity to extracellular monovalent cations. Replacement of extracellular Na+ with K+, whi...

Crude wild pear lipoxygenase (LOX) from ripe Kurdistan wild pears was used in this study. Extracted crude LOX was assayed spectrophotometrically for raw, ripe wild pear lipoxygenase and after 7-day storage. The effects of different buffers and pHs, substrate preparations, temperature, inhibitors and metal ions on LOX activity were evaluated at three conditions. The enzyme was most active with H...

DNA condensation and charge inversion usually occur in solutions of multivalent counterions. In the present study, we show that the organic monovalent ions of tetraphenyl chloride arsenic (Ph4As) can induce DNA compaction and even invert its electrophoretic mobility by single molecular methods. The morphology of condensed DNA was directly observed by atomic force microscopy (AFM) in the presenc...

The electrochemical properties of diazophenylcalix[4]arenes bearing ortho-carboxyl group (o-CAC) and ortho-ester group (o-EAC), respectively, in the presence of various metal ions were investigated by voltammetry in CH3CN. o-CAC and o-EAC showed voltammetric changes toward divalent metal ions and no significant changes with monovalent alkali metal ions. However, o-CAC preferentially binds with ...

We have examined the interaction between internal and external ions in the pore of potassium channels. We found that external tetraethylammonium was able to antagonize block of Shaker channels by internal TEA when the external and internal solutions contained K(+) ions. This antagonism was absent in solutions with Rb(+) as the only permeant ion. An externally applied trivalent TEA analogue, gal...