Voltage-gated K(+) (Kv) channel activation depends on interactions between voltage sensors and an intracellular activation gate that controls access to a central pore cavity. Here, we hypothesize that this gate is additionally responsible for closed-state inactivation (CSI) in Kv4.x channels. These Kv channels undergo CSI by a mechanism that is still poorly understood. To test the hypothesis, w...

Hyperpolarization-activated cation (HCN) channels regulate pacemaking activity in cardiac cells and neurons. Our previous work using the specific HCN channel blocker ZD7288 provided evidence for an intracellular activation gate for these channels because it appears that ZD7288, applied from the intracellular side, can enter and leave HCN channels only at voltages where the activation gate is op...

Niflumic acid (NFA) is a member of the fenamate class of nonsteroidal anti-inflammatory drugs. This compound and its derivatives are used worldwide clinically for the relief of chronic and acute pain. NFA is also a commonly used blocker of voltage-gated chloride channels. Here we present evidence that NFA is an efficient blocker of chloride-permeable glycine receptors (GlyRs) with subunit heter...

A physical model of selective "ion binding" in the L-type calcium channel is constructed, and consequences of the model are compared with experimental data. This reduced model treats only ions and the carboxylate oxygens of the EEEE locus explicitly and restricts interactions to hard-core repulsion and ion-ion and ion-dielectric electrostatic forces. The structural atoms provide a flexible envi...

INTRODUCTION In our previous study, we found that negatively charged gold nanoparticles with spermidine have the potential of blocking inwardly rectifying potassium channels (Kir), both at the cellular and the tissue level. METHODS For the purpose of the present study, we purified the cytoplasmic domain of the Kir 3.1 receptor from Escherichia coli. Using single particles with surface coating...

bamboo-structured carbon nanotubes are grown on co-mo/mcm-41 catalyst in the temperature range of 873-973 k by thermal chemical vapor deposition of acetylene. this study shows that the purified carbon nanotubes have open tips and the metals of the catalyst are not encapsulated. thus, the bamboo-structure seems to grow from the base. pore size distribution of the product is quite narrow and is i...

This study compared membrane fouling in a sponge-submerged membrane bioreactor (SSMBR) and a conventional membrane bioreactor (CMBR) based on sludge properties when treating synthetic domestic wastewater. In the CMBR, soluble microbial products (SMP) in activated sludge were a major contributor for initial membrane fouling and presented higher concentration in membrane cake layer. Afterwards, m...

Each species from bacteria to human has a distinct genetic fingerprint. Therefore, a mechanism that detects a single molecule of DNA represents the ultimate analytical tool. As a first step in the development of such a tool, we have explored using a nanometer-diameter pore, sputtered in a nanometer-thick inorganic membrane with a tightly focused electron beam, as a transducer that detects singl...

The standard model of injection-induced seismicity considers changes in Coulomb strength due solely to changes in pore pressure. We consider two additional effects: full poroelastic coupling of stress and pore pressure, and time-dependent earthquake nucleation. We model stress and pore pressure due to specified injection rate in a homogeneous, poroelastic medium. Stress and pore pressure are us...

excess pore pressure under seismic loadings has always been a main concern in geotechnical engineering practices. the phenomenon in soil can cause an effective stress and hence cause the shear strength of the soil to decrease considerably and large deformations to occur in the area. generally, increases in pore pressure occur in un-drained conditions. if it is formed, its consequences decrease ...