Preparation and characterization of fiber-textured SrAl2O4:Eu films grown using a homo-buffer layer

This paper describes the preparation and characterization of fiber-textured SrAl₂O₄:Eu films on a quartz glass substrate using a homo-buffer layer. The effect of the buffer layer on the crystallinity and adhesion was investigated by cross-section transmission electron microscopy and X-ray diffraction (XRD). The results show that the prepared film was not only well crystallized but also highly textured. The preferred orientation of this textured film was confirmed to be (0 3 1) by pole figure measurement. In addition, this film exhibits excellent optical transparency, with an average transmittance of more than 80% in the visible range.     

Structure elucidation of cyasterone stereoisomers isolated from Cyathula officinalis

Chemical investigation of ecdysteroidal constituents of the roots and stems of Cyathula officinalis led to the isolation of two cyasterone stereoisomers, 2 and 3, together with the known cyasterone 1. The structures of compounds 2 and 3 were determined to be 28-epi-cyasterone and 25-epi-28-epi-cyasterone, respectively, by means of spectroscopic analysis. X-Ray structures of 1 and 2 confirmed the 24S,25S,28R configuration for 1 and 24S,25S,28S for 2.     

Carbonyl olefination utilizing an alkyl halide-titanocene(II) system

Ketones, aldehydes, esters and lactones are transformed into olefins by treatment with the organotitanium species formed from alkyl halides and titanocene(II).     

Reorientational motion of acetone in solutions

Dipolar correlation functions of acetone in various solvents are obtained by Fourier transform of infrared spectra. The analysis of the shapes of correlation functions shows that the reorientational process is diffusional in the time scale longer than about 0.3 × 10^?12 sec. In nonpolar solvents the ratios of correlation times τ_A : τ_B : τ_C do not vary in different solvents, and the reorientation around b axis is more restricted than around the other axis. The length of correlation time is dependent on the density of solvent rather than the viscosity. These observations are unexpected if only the electrostatic interaction is considered. In polar solvents correlation times are longer than in nonpolar solvents and the tendency is especially remarkable in τ_B. An electrostatic interaction between polar molecules seems to be responsible for these observations. The solvent effect on the frequency shifts of carbonyl stretching vibration is consistent with the result of correlation times.     

Enantiomeric resolution of amino acid derivatives on molecularly imprinted polymers as monitored by potentiometric measurements

Potentiometric measurements have been applied to the detection of enantiomeric separations on molecularly imprinted polymers. A flow-through column electrode, based on the use of polymers imprinted against L-phenylalanine anilide, is described. The electrode consisted of a glass column in which the polymer was packed and where the end frits constituted the electrodes. The flow stream potential across the column can be continuously recorded as solvent is pumped through the system. The column resolved the enantiomers of phenylalanine anilide as detected by both UV absorption and potentiometric measurements and the recorded signals could be correlated with the concentration of phenylalanine anilide. The calibration graphs obtained for the UV absorption of phenylalanine anilide were linear over the concentration range investigated, whereas the potentiometric signal was shown to be exponentially linear with concentration. The application of molecular imprints to the preparation of supports suitable for chromatographic separations of enantiomers and for the preparation of specific electrodes is discussed.     

Low p T phenomena in A+A and p+A collisions at mid-rapidity

CERN experiment NA44 measures pion and kaon distributions at p _T = 0–320 MeV/c at midrapidity in p+A and A+A collisions at 450 and 200A GeV/c, respectively. Pion production from p+Pb and A+A is slightly enhanced at low p _T relative to p+Be, but less than observed at target rapidity. The low p _T behavior can be understood in the context of the RQMD model as arising from baryonic resonance decays.     

Reduction of carbonyl groups to the corresponding methylenes with Ni-Al alloy in water

The reduction of carbonyl compounds 1a-h using Ni-Al alloy in water under reflux proceeded to give the corresponding methylene compounds 2a-h within 2 h in 89.0-99.8% relative yields.     

Viscometric assay for determining lysozyme activity

A method was developed for determining the activity of lysozyme using two pipettes as a viscometer. The proposed viscometric assay uses carboxymethylchitin as a substrate and measures the enzyme activity at 22°C. The method requires only simple manipulations with the use of readily available laboratory equipment and the determination of enzyme activity is rapid.