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We have investigated the local free volume and its thermal fluctuation in an amorphous polymethylsilsesquioxane (PMSQ) consisting only of T3 (CH3SiO3/2) and T2 (CH3Si(OH)O2/2) units using photoisomerization of azobenzene molecularly dispersed in the PMSQ films as a photoprobe over a wide temperature range (4−300 K). Photoisomerization profiles are discussed on the basis of three parameters, i.e., first-order plots, final cis fractions, and three-component analysis, for uncured and silanol-condensation-cured PMSQ's. The final cis fraction in the uncured PMSQ decreases markedly below 250 K, which has never been observed in linear polysiloxanes, MQ resins, or carbon-based polymers. The effect of low-molecular-weight components in the PMSQ was evaluated using fractionated PMSQ's by molecular weight. The effect of hydrogen bonding by a silanol group was also studied by temperature dependence of infrared spectra. These results suggest that the low-molecular-weight components with silanol groups fill local vacant space resulting in the anomalous decrease in the final cis fraction for the uncured PMSQ below 250 K.

The content of 9 types of isoflavonoids (daidzein, glycitein, genistein, formononetin, biochanin A, coumestrol, daidzin, glycitin and genistin) in 34 domestic or imported raw beans including soybeans, 7 immature beans and 5 bean sprouts consumed in Japan were systematically analyzed. Each isoflavonoid was analyzed in total after acid hydrolysis to the aglycone, and intact individual isoflavonoids were also analyzed without hydrolysis. After the sample clean up, daidzein, glycitein, genistein, formononetin, biochanin A, daidzin, glycitin and genistin were determined by HPLC with a diode array detector and coumestrol was determined by spectrofluorimetry. The content and composition of isoflavonoids varied greatly between soybean sprouts, immature soybeans and mature beans of the same type but of different source. Isoflavonoid content was highest in mature soybeans. The composition of isoflavonoids differed in each growth stage of soybeans. In other beans, the largest content of isoflavonoids was found in mature chickpeas, but this value was less than 1/27 of the isoflavonoid content in mature soybeans. Thus, the contribution of beans other than soybeans to the daily intake of isoflavonoids in a Japanese diet is negligible.Key words ---isoflavonoid, bean, acid hydrolysis, high performance liquid chromatography, diode array detection, spectrofluorometric detection tivities 1) and reported to be protective against cancer, cardiovascular diseases and osteoporosis. [3][4][5][6][7][8][9] Much research has been reported about the content of isoflavonoids in soybeans and soybean-derived processed foods. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] In contrast, there are few reports about the isoflavonoid content in beans other than soybeans. 11,12,18,23) Japanese people are reported to ingest isoflavonoids mainly through the consumption of soybeans and its derived processed foods. 20) Recently, we estimated that the Japanese daily intake of isoflavonoids from soybeans and soybean-based processed foods is 27.80 mg per day (daidzein 12.02 mg, glycitein 2.30 mg and genistein 13.48 mg).24) However, isoflavonoid intake from the consumption of immature beans, sprouts and beans other than soybeans has not been elucidated. Here we have measured the content of isoflavonoids in mature and immature beans and bean sprouts consumed in Japan, and have compared the content and composition variation between different types and different growth stages of the beans. MATERIALS AND METHODSMaterials ---Genistein, formononetin and biochanin A were purchased from Extrasynthèse (Genay, France). Daidzein, daidzin, genistin, glycitein and glycitin were from Fujicco Co., Ltd. (Kobe, Japan). Coumestrol was obtained from Fluka Chemie AG (Bucks, Switzerland). Flavone, 2,6-dit-butyl-4-methylphenol (BHT) and dimethyl sulfoxide (DMSO) were from Wako Pure Chemical Industries, Ltd. (Osaka, Japan). The chemical structures of these isoflavonoids and flavone are shown in Fig. 1. Acetonitrile, ethanol, n-hexane and methanol were analytical grade...

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We examined four type 1 polioviruses isolated from the stools of patients with vaccine-associated paralytic poliomyelitis in China. All of these isolates were shown to be Sabin derived viruses by restriction fragment length polymorphism assay after polymerase chain reaction and by sequencing of the viral genome encoding the viral coat protein, VP1. However, the same analysis of the 3D coding region suggested that two of the four isolates had the sequence of wild type poliovirus in the tested region. Furthermore there were also point mutations in the 5' non-coding region. One was a single base change from U to C at nucleotide position 525, and the other three were from G to A at position 480. All the four strains were more neurovirulent that Sabin type 1 virus in transgenic mice with human poliovirus receptor gene. The data showed that the nucleotide positions of type 1 poliovirus which were identified to be in favor of the high neurovirulence were indeed changed during natural transmission, and suggested that the point mutation alone or a recombination of the vaccine type with wild type genome results in an acquisition of neurovirulence.