Molecular dynamics simulations of a bacterial potassium channel (KcsA) embedded in a phospholipid bilayer reveal significant differences in interactions of the selectivity filter with K(+) compared with Na(+) ions. K(+) ions and water molecules within the filter undergo concerted single-file motion in which they translocate between adjacent sites within the filter on a nanosecond timescale. In ...

SUMMARY Validating an earth model by simulating a migration image is an important step in a shared earth environment. However, the high computational cost of generating 3D synthetic data, followed by the process of migration, limits the number of scenarios that can be validated. To overcome this computational cost, a novel strategy is used where a migration image is simulated by filtering a mod...

objective(s):n-myc downstream regulated gene 2 (ndrg2) is a candidate gene for tumor suppression. the expression of ndrg2 is down-regulated in several tumors including lung cancer. the aim of this study was to explore the effect of ndrg2 overexpression on invasion, migration, and enzymatic activity of matrix metalloproteinase-2 (mmp-2) and -9 (mmp-9) in human lung adenocarcinoma a549 cells.  ma...

PURPOSE To evaluate the safety and effectiveness of the retrievable Option inferior vena cava (IVC) filter in patients at risk for pulmonary embolism (PE). MATERIALS AND METHODS This was a prospective, multicenter, single-arm clinical trial. Subjects (N = 100) underwent implantation of the IVC filter and were followed for 180 days; subjects whose filters were later removed were followed for 3...

K(+) channels exhibit strong selectivity for K(+) ions over Na(+) ions based on electrophysiology experiments that measure ions competing for passage through the channel. During this conduction process, multiple ions interact within the region of the channel called the selectivity filter. Ion selectivity may arise from an equilibrium preference for K(+) ions within the selectivity filter or fro...

In this work, we consider the tessellations (or tilings) of Euclidean and hyperbolic planes using copies of a regular polygon. We introduce the concept of k-type of vertices and edges, which allow a thorough control of these elements when the tessellation increases, and we obtain an enumeration for the vertices, edges, and polygons at a given distance. Partially funded by a grant from Fapesp (2...

K(+) efflux through K(+) channels can be controlled by C-type inactivation, which is thought to arise from a conformational change near the channel's selectivity filter. Inactivation is modulated by ion binding near the selectivity filter; however, the molecular forces that initiate inactivation remain unclear. We probe these driving forces by electrophysiology and molecular simulation of MthK,...

Migration plays an important role in the formation of tumor metastases. Nonetheless, little is known about electrophysiological phenomena accompanying or underlying migration. Previously, we had shown that in migrating alkali-transformed Madin-Darby canine kidney focus (MDCK-F) cells a Ca(2+)-sensitive 53-pS K+ channel underlies oscillations of the cell membrane potential. The present study def...