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,...

Quantum mechanics/molecular mechanics (QM/MM) Car-Parrinello simulations were performed to estimate the coordination numbers of K(+) and Na(+) ions in the selectivity filter of the KcsA channel, and in water. At the DFT/BLYP level, K(+) ions were found to display an average coordination number of 6.6 in the filter, and 6.2 in water. Na(+) ions displayed an average coordination number of 5.2 in ...

424  Abstract—Image denoising is one of the fundamental problems in image processing. In this paper, a novel approach to suppress noise from the image is conducted by applying the interquartile range (IQR) which is one of the statistical methods used to detect outlier effect from a dataset. A window of size kk was implemented to support IQR filter. Each pixel outside the IQR range of the kk ...

Potassium channels selectively conduct K(+), primarily to the exclusion of Na(+), despite the fact that both ions can bind within the selectivity filter. Here we perform crystallographic titration and single-channel electrophysiology to examine the competition of Na(+) and K(+) binding within the filter of two NaK channel mutants; one is the potassium-selective NaK2K mutant and the other is the...

Bloom filters are a well known data-structure that supports approximate set membership queries that report no false negatives. Each element in the universe represented by the bloom filter is associated with k random bits in the structure. Traditional bloom filters, therefore, require k non-local memory operations to insert an element or perform a lookups. For very large bloom filters, these k l...

We modified the Adaptive Noise Cancellation procedure of Widrow et al. (11 for use as an adaptive band-pass filter to process Steady-State Evoked Potentials (SSEPs). The adative filter yields an approsimate 10 dB improvement in Signal to Noise Ratio over the Discrete Fourier Transform. Introduction Steady-state evoked potentials (SSEPs) are comprised of narrow-band signals buried in broad-band ...

In the Kv2.1 potassium channel, binding of K(+) to a high-affinity site associated with the selectivity filter modulates channel sensitivity to external TEA. In channels carrying Na(+) current, K(+) interacts with the TEA modulation site at concentrations </=30 microM. In this paper, we further characterized the TEA modulation site and examined how varying K(+) occupancy of the pore influenced ...