Development of an experimental database of EUV spectra from highly charged ions of medium to high Z elements in the Large Helical Device plasmas

We are developing an experimental database of extreme ultraviolet spectra from highly charged ions using optically thin high-temperature plasmas produced in the Large Helical Device. Spectra from a variety of elements with atomic numbers ranging from 36 to 83 have been systematically recorded in the range of 1–20 nm by a grazing incidence spectrometer. For higher Z elements from tin onward, discrete or quasicontinuum spectral features from n=4 (N-shell) ions are mainly observed depending upon the plasma temperature, which leads to some new experimental identifications of spectral lines. On the other hand, major emitters are n=3 (M-shell) ions for medium Z elements from krypton to ruthenium. The calculated wavelengths for Δn≠0 transitions agree well with the measurements and the calculated wavelengths are systematically shifted to shorter wavelengths for Δn=0 transitions associated with inner-subshell excited configurations.     

Drying dissipative structures of Chinese black ink on a cover glass and in a dish

Macroscopic and microscopic dissipative structural patterns are formed in the course of drying a suspension of Chinese black ink on a cover glass and in a dish. The time for the drying and the pattern area increased as the particle concentration increased. The broad ring patterns of the hills accumulated with the particles formed around the outside edges on a macroscopic scale. The height and the width of the broad ring increased as the particle concentration increased. The spokelike patterns of the rims accumulated with particles were also formed on a macroscopic scale. Microscopic patterns of colloidal accumulation were observed over the whole region of the pattern area. Various types of convection cells were observed on a cover glass and in a dish at 25–80 °C. A time-resolved observation of the drying process was also made. The convections of water and the colloidal particles at different rates under gravity and the translational and rotational Brownian movement of the particles were important for the macroscopic pattern formation. Microscopic patterns were determined by the translational Brownian diffusion of the particles and the electrostatic and the hydrophobic interactions between the particles and/or between the particles and the cell wall in the course of the solidification of the particles.     

Measurement of the electrophoretic mobility of sheep erythrocytes using microcapillary chips

Cell electrophoretic mobility (EPM) can be used to characterize individual cells. The purpose of this study is to establish reproducible and reliable cell EPM values obtained using microcapillary electrophoresis (microCE) chips. We studied cell electrophoresis on microCE chips through the comprehensive measurement of EPM and zeta potential. The inner wall of microchannels in microCE chips was coated with three kinds of reagents, namely bovine serum albumin (BSA), gelatin, and 2-methacryloyloxyethylphosphorylcholine (MPC) polymer to prevent nonspecific adhesion and interaction between cells and the inner wall. Electrophoresis was conducted in phosphate-buffered saline (pH 4-9) using erythrocytes extracted from sheep whole blood. Electroosmotic flow (EOF) mobility was measured using noncharged particles, and then the true EPM was calculated by subtracting the EOF mobility from the electromigration. MPC polymer coatings in microCE chips reduced the zeta potential of the inner wall and fully prevented nonspecific adhesion. EPM data obtained using microCE chips were almost the same and reproducible over a wide range of pH irrespective of the coating reagent used. In conclusion, reliability in the measurement of cell EPM using microCE chips was realized.     

Photophysical studies of 9,10-phenanthrenequinones

The characterization of the excited states of 9,10-phenanthrenequinone (PQ) and its derivatives substituted in the 3 and 6 positions with methoxy (PQ1), chloro (PQ2), methyl (PQ3) and fluoro (PQ3) was carried out using steady-state UV-Visible absorption spectroscopy and phosphorescence emission spectroscopy at room temperature and at 77 K. Nanosecond laser flash photolysis was used to obtain the time resolved spectra from the triplet emission decays. The compounds presented phosphorescence in benzene, chlorobenzene and acetonitrile solutions at room temperature and at 77 K. The phosphorescence of the methoxy derivative, however, was observed only at low temperature. The derivatives showed a slightly higher triplet energy than PQ. The Hammett plots were applied to correlate singlet and triplet energies with sigma values that account for resonance and the radical character. It is observed that singlet and triplet energies increase with electron donating groups.     

Direct beta-alkylation of secondary alcohols with primary alcohols catalyzed by a CpIr complex

A new catalytic system for beta-alkylation of secondary alcohols has been developed. In the presence of [CpIrCl(2)](2) (Cp = pentamethylcyclopentadienyl) catalyst and base, the reactions of various secondary alcohols with primary alcohols give beta-alkylated higher alcohols in good to excellent yields without any hydrogen acceptor or hydrogen donor. This reaction proceeds via successive hydrogen-transfer reactions and aldol condensation. [reaction: see text]     

Efficient microwave-assisted tandem N- to S-acyl transfer and thioester exchange for the preparation of a glycosylated peptide thioester

A peptide carrying a mercaptomethylated proline derivative at the C-terminus was prepared by solid-phase peptide synthesis (SPPS) and converted to the thioester of 3-mercaptopropionic acid (MPA) by aqueous MPA under microwave irradiation conditions. This post-SPPS thioesterification reaction was successfully applied to the synthesis of a glycopeptide thioester composed of 25 amino acid (AA) residues, which was then used for the preparation of a 61-AA glycopeptide by the thioester condensation method.     

A highly practical instant catalyst for cyclotrimerization of alkynes to substituted benzenes

[reaction: see text] A 2-(2,6-diisopropylphenyl)iminomethylpyridine (1a)/CoCl(2).6H(2)O/Zn reagent has been developed as an effective instant catalyst for the intra- and intermolecular cyclotrimerization of alkynes to substituted benzenes, making the method extremely practical since the reagent, 1a/CoCl(2).6H(2)O/Zn, is inexpensive and easy to handle and the reaction is less sensitive to moisture and is reasonably general.