Pawns are behavioural mutants (in one of three genes) of Paramecium aurelia that have lost, to varying degrees, the reversal response which is thought to depend on the calcium influx during excitation. This report shows that all of the single and double mutants have reduced active inward (calcium) current, the reduction correlating with the degree of behavioural deficit. All of the mutants disp...

We perform density functional theory (DFT) calculations on molecular junctions consisting of a single molecule between two Au(111) electrodes. The molecules consist of an alkane or aryl bridge connecting acceptor, donor or thiol endgroups in various combinations. The molecular geometries are optimized and wavefunctions and eigenstates of the junction calculated using the DFT method, and then th...

We demonstrate large rectification ratios (> 100) in single-molecule junctions based on a metal-oxide cluster (polyoxometalate), using a scanning tunneling microscope (STM) both at ambient conditions and at low temperature. These rectification ratios are the largest ever observed in a single-molecule junction, and in addition these junctions sustain current densities larger than 10(5) A cm(-2)....

CA2+-permeable glutamate receptors assembled from subunits containing a GLN residue at the RNA editing site in membrane domain 2 show strong inward rectification. In HEK 293 cells transfected with the kainate receptor subunit GluR6(Q), inward rectification is lost in outside-out patches, suggesting a role for diffusible, cytoplasmic factors. Inclusion of different polyamines in the internal sol...

Making semiconductor devices based on single-walled carbon nanotubes (SWCNT) is one of the more compelling potential applications of these long but ultrathin structures. We see asymmetric voltage-current behavior across a random network of SWCNTs contacted by asymmetric metal electrodes (Au/Al). No effort was made to align the SWCNTs or to eliminate metallic nanotubes in our devices, procedures...

We analyze the dynamics of Brownian ratchets in a confined environment. The motion of the particles is described by a Fick-Jakobs kinetic equation in which the presence of boundaries is modeled by means of an entropic potential. The cases of a flashing ratchet, a two-state model, and a ratchet under the influence of a temperature gradient are analyzed in detail. We show the emergence of a stron...

Image rectification is the process of warping a pair of stereo images in order to align the epipolar lines with the scan-lines of the images. Once a pair of images is rectified, stereo matching can be implemented in an efficient manner. Given the epipolar geometry, it is straightforward to define a rectifying transformation, however, many transformations will lead to unwanted image distortions....

Single-walled carbon nanotubes (SWCNT) were prepared using iron catalysts deposited by indirect evaporation on silicon substrate covered with 500 nm-thick thermal oxide. Diode SWCNT devices have been fabricated using Au and Al, as the asymmetric metal contacts, and a random network of metallic and semiconducting nanotubes as the device channel. No effort was made to align the SWCNTs or to elimi...