Superconductivity in graphite-potassium intercalation compound C8K

The critical temperature T_c, and the angular and temperature dependences of the upper critical field H_c2 in highly oriented pseudo-single crystals of C₈K have been studied by using a magnetic susceptibility measurement. The magnetic susceptibility abruptly changes around 139 mK at zero field. The angular dependence of H_c2 shows a very large anisotropy.     

p-Anisyl group: A versatile protecting group for primary alcohols

A primary alcohol can be protected as a highly stable p-anisyl ether, which undergoes mild oxidative deprotection by ceric ammonium nitrate.     

Annealing behavior of spin density in UHV evaporated amorphous silicon

The ESR of amorphous silicon films evaporated in UHV has been measured at room temperature. Up to 900°C the annealing behavior of the spin density in the amorphous silicon films is quite different from that of films deposited in conventional HV.     

Highly selective acylation of amines and alcohols by poly(3-acyl-2-oxazolone)

Poly(3-acyl-2-oxazolone) serves as a convenient reagent for highly chemo- and regioselective acylation of polyamines, amino-alcohols and polyalcohols.     

Baryon duality solutions with the harmonic-oscillator spectrum and the amplitude signs in πN→πΔ

By constructing exact exchange-degenerate solutions of baryons with the harmonic-oscillator spectrum for a set of reactions MB→M′B′, MB → M′D′ and MD → M′D′, we investigate the duality constraints on the amplitude signs in MB → M′D′. It is shown that the amplitude signs determined by duality are consistent with those predicted by the extended version of SU(6)_W symmetry with the universal dominance of the ΔL_Z = 0 or ΔL_Z = ±1 amplitude in the mesonic transitions of the baryons.     

Population pharmacokinetics of phenytoin from routine clinical data in Japan: an update

Routine clinical pharmacokinetic data collected from outpatients receiving phenytoin (PHT) were reanalyzed to estimate population pharmacokinetic parameters. There were 756 steady-state PHT concentrations and associated dosage rates (mg/d) from 334 outpatients. The data were analysed using nonlinear mixed effects model (NONMEM), a computer program designed for population pharmacokinetic analysis that allows pooling of data from many individuals. The influence of weight, co-anticonvulsants on the maximum elimination rate (Vm) and age, co-anticonvulsants on the Michaelis-Menten constant (Km) and the influence of dosage form on the bioavailability (F) of PHT were investigated. The Vm and Km of a 60 kg adult outpatient treated with PHT alone were estimated to be 325 mg/d and 2.41 micrograms/ml, respectively, while for a same size individual taking PHT with co-anticonvulsants respective estimates were 351 mg/d and 3.18 micrograms/ml. The parameter of a power function of weight was estimated to adjust Vm for body size. The best function adjusts Vm in proportion to weight to the 0.737 power. The Km for patients less than 15 years old was 24.8% less than that of adults. Assuming the F of PHT to be 1 in patients prescribed a tablet, the F value in patients prescribed a powder was [1-exp(-9.92/Dij)]; Dij is the daily dose of PHT for the ith Cpss in the jth patients (mg/kg/d).     

Frequency domain characteristics of linear operator to decompose a time series into the multi-components

Frequency domain properties of the operators to decompose a time series into the multi-components along the Akaike's Bayesian model (Akaike (1980, Bayesian Statistics, 143–165, University Press, Valencia, Spain)) are shown. In that analysis a normal disturbance-linear-stochastic regression prior model is applied to the time series. A prior distribution, characterized by a small number of hyperparameters, is specified for model parameters. The posterior distribution is a linear function (filter) of observations. Here we use frequency domain analysis or filter characteristics of several prior models parametrically as a function of the hyperparameters.     

Selective surface modification technique for improvement of chromatographic separation selectivity for sugar derivatives.

Highly cross-linked macroporous polymers were prepared utilizing ethylene dimethacrylate as a cross-linking agent, in the presence or absence of methyl-alpha-D-glucoside as a kind of template molecule with methacrylic acid as a functional monomer. After the preparation of the polymers, we applied a high temperature to the cross-linked polymers to study the changes of adsorption properties of the polymers for sugar derivatives including the template molecule utilized. Interestingly, the heat treatment up to 250 degrees C afforded improvement of relative adsorption affinity for several sugar derivatives including the template molecule, while heat treatment up to 150 degrees C did not afford those improvements. The detailed studies including polymers prepared using acrylic acid as a functional monomer instead of methacrylic acid prove that temperatures higher than the Tg temperature of the polymer derived from a functional monomer such as methacrylic acid and higher than the melting point (mp) of the sugar template are necessary to afford the observed improvement of relative affinity based on the surface modification effects through the heat treatment to cross-linked polymers.     

Temperature dependence of intersystem crossing of pyrene

The temperature dependence of the rate constant for intersystem crossing from S₁ of pyrene was determined by means of a method proposed previously. In contrast to the conclusions of Stevens, Thomaz and Jones, and of Kropp, Dawson and Windsor, we conclude that both temperature-independent and temperature-dependent intersystem crossing processes exist. These two processes contribute equally at ≈ 150 K.