Gate-readout and a 3D rectification effect for giant responsivity enhancement of asymmetric dual-grating-gate plasmonic terahertz detectors.

We experimentally investigated the asymmetric dual-grating-gate plasmonic terahertz (THz) detector based on an InGaAs-channel high-electron-mobility transistor (HEMT) in the gate-readout configuration. Throughout the THz pulse detection measurement on the fabricated device, we discovered a new detection mechanism called the "3D rectification effect" at the positive gate bias application, which is a cooperative effect of the plasmonic nonlinearities in the channel with the diode nonlinearity in the heterobarrier between the InGaAs channel layer and the InAlAs spacer/carrier-supply/barrier layers, resulting in a giant enhancement of the detector responsivity. We also found that an undesired long-tail waveform observed on the temporal pulse photoresponse of the device is due to trapping of carriers to the donor levels in the silicon -doped carrier-supply layer when they tunnel through the barrier to the gate and can be eliminated completely by introducing the so-called inverted-HEMT structure.

Potassium and sodium ion complexes with a partial peptide of the selectivity filter in K channels studied by cold ion trap infrared spectroscopy: the effect of hydration.

Potassium channels allow K+ to rapidly diffuse, while the selectivity filter (SF) actively blocks Na+. The presence of water in the SF during ion translocation remains under debate due to the experimental and computational challenges in characterizing the interactions between water, ions, and the SF. Our bottom-up approach has been applied to a system composed of a partial peptide of the SF (Ac-tyrosine-NHMe) with a metal ion and a single water molecule to probe these interactions.

Gilvimarinus japonicus sp. nov., a cellulolytic and agarolytic marine bacterium isolated from coastal debris.

A cellulolytic and agarolytic bacterial strain, designated 12-2T, was isolated from a piece of cotton rope fragment washed ashore on a beach and was studied phenotypically, genotypically and phylogenetically. Analyses of 16S rRNA and gyrB gene sequences and DNA base composition suggested that the strain is a member of the genus Gilvimarinus. However, levels of 16S rRNA and gyrB gene sequence similarity between it and the type strains of Gilvimarinus species were no higher than 97.