Split instability of a vortex in an attractive Bose-Einstein condensate

An attractive Bose-Einstein condensate with a vortex splits into two pieces via the quadrupole dynamical instability, which arises at a weaker strength of interaction than the monopole and the dipole instabilities. The split pieces subsequently unite to restore the original vortex or collapse.     

Investigation of the possibility of geometrical electrophoresis

We investigate the possibility of geometrical electrophoresis, which is based on nanofabrication techniques. (GEE) utilizes geometrical effects during electrophoresis, which are generated by physical interactions between walls and a macromolecule confined in spaces smaller than the Flory radius. When a polymer is injected into a small space, confinement energy is usually required. However, the confinement energy form depends on the geometry of the space. In the case of electrophoresis, the electric field itself changes depending on the geometry. Using a nanofabricated quartz chip with a curved channel, we investigated electrophoretic behavior of high molecular weight DNA based on the curvature effect.     

Association of tannins and related polyphenols with the cyclic peptide gramicidin S

The association of 10 different tannins and related polyphenols with gramicidin S, a cyclic peptide having a rigid beta-turn structure, has been examined using 1H-NMR spectroscopy. In the presence of pentagalloylglucose and epigallocatechin-3-O-gallate, the proton signals due to proline and the adjacent phenylalanine moieties selectively shifted to up field, suggesting a regioselective association with the beta-turn structure. The association was also supported by the observation of intermolecular nuclear Overhauser effects between epigallocatechin-3-O-gallate and the peptide. In contrast, ellagitannins, biogenetically derived from pentagalloylglucose, showed small and non-selective chemical shift changes, suggesting that interaction with these tannins is relatively weak. The hydrophobicity of the tannin molecules and the steric hindrance of the interaction site are thought to be important in the association.     

Investigation of the release test method for the topical application of pharmaceutical preparations: release test of cataplasm including nonsteroidal anti-inflammatory drugs using artificial sweat

A simple procedure for determining the in vitro release profile of a cataplasm for use in a quality control procedure has been developed. Since the disk assembly in the USP for patch dosage forms was unsuited for use in a release test due to penetration of the dissolution medium into the cataplasm from the screw part of the device and the cataplasm swelled, new holders were designed. In the new holder, a cataplasm is held in position by sandwiching it between a stainless-steel O-ring and a silicon O-ring on the stainless steel board, 2 acrylic boards hold the O-rings and the stainless steal board, and the entire assembly is placed at the bottom of the dissolution vessel. The release profile was determined using the "Paddle over Disk" method in USP26. Furthermore, in order to prevent the swelling of the cataplasm, artificial sweat was used as the dissolution medium. The release profiles of the nine marketed brands of cataplasm containing indomethacin, ketoprofen, and flurbiprofen, respectively, were determined over a 12-h period. By adjusting the ion concentration and volume of the media, and the release surface-area of the cataplasm exposed to each medium, the procedure was found to be reproducible for in vitro release characterization of nine marketed brands. This shows that this technique can be used as a quality control tool for assuring product uniformity.     

Doppler-free resonant Raman auger spectroscopy of Ne+ 2s2p(5)3p excited states

Using very high resolution achieved by the Doppler-free resonant Raman Auger technique, we have resolved the lowest terms of the series of inner-valence excitations 2s2p(5)((1,3)P)np 2S, 2P, and 2D in Ne+. The measured Auger anisotropic parameters and branching ratios help to establish the assignments of these levels. The measured lifetime widths are in reasonable agreements with ab initio calculations available in the literature.     

0.85-PW, 33-fs Ti:sapphire laser

We have successfully produced a laser pulse with a peak power of 0.85 PW for a pulse duration of 33 fs in a four-stage Ti:sapphire amplifier chain based on chirped-pulse amplification. To our knowledge this result represents the highest peak power pulses yet produced in any Ti:sapphire chirped-pulse amplification system.     

Vortex phase diagram in rotating two-component Bose-Einstein condensates

We investigate the structure of vortex states in rotating two-component Bose-Einstein condensates with equal intracomponent but varying intercomponent-coupling constants. A phase diagram in the intercomponent-coupling versus rotation-frequency plane reveals rich equilibrium structures of vortex states. As the ratio of intercomponent to intracomponent couplings increases, the interlocked vortex lattices undergo phase transitions from triangular to square, to double-core lattices, and eventually develop interwoven "serpentine" vortex sheets with each component made up of chains of singly quantized vortices.