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81.
Mitsuru Ueda Yoshikatu Seino Yuko Haneda Masanobu Yoneda Jun-Ichi Sugiyama 《Journal of polymer science. Part A, Polymer chemistry》1994,32(4):675-681
tert-Butyl substituted poly (aryl ether ketone)s with relatively high molecular weights were prepared by the Ni-catalyzed polymerization of tert-butyl substituted aromatic dichlorides containing ether ketone unit. These polymers were amorphous and soluble in common organic solvents, such as THF, dichloromethane, and chloroform. De-tert-butylation of the polymer by the treatment of trifluoromethanesulfonic acid in the presence of toluene proceeded smoothly and produced crystalline poly (aryl ether ketone). © 1994 John Wiley & Sons, Inc. 相似文献
82.
Koichiro Yonetake Kunio Maruyama Jun-Ichi Sugiyama Toru Masuko Mitsuru Ueda 《Journal of polymer science. Part A, Polymer chemistry》1994,32(8):1415-1421
Poly[4-(4-hydroxyphenoxy) benzoic acid] was prepared by the bulk polycondensation of 4-(4-acetoxyphenoxy) benzoic acid. Polycondensation was conducted at 350°C for 3 h under a reduced pressure of 0.1 mmHg and gave a polymer with X?n of 255. The polymer was characterized by elemental analysis, IR spectroscopy, differential scanning calorimetry, and wide-angle X-ray measurement. The crystal/nematic and nematic/isotropic phase transition temperatures of polymer, which depend on the molecular weight, were observed at about 300°C and 410°C, respectively. The polymers with low molecular weights showed nematic textures above 300°C. This nematic/isotropic phase transition temperature is lower than that of poly (4-hydroxybenzoic acid). This thermal behavior of polymer comes from ether units, which increase the flexibility (the rotation or torsion of skeletal bonds) of the polymer chain. © 1994 John Wiley & Sons, Inc. 相似文献
83.
Makoto Kunisada Taro Masaki Ryusuke Ono Hironobu Morinaga Eiji Nakano Flandiana Yogianti Kunihiro Okunishi Hiroshi Sugiyama Chikako Nishigori 《Photochemistry and photobiology》2013,89(3):649-654
The UVA is currently thought to be carcinogenic because, similar to UVB, it induces the formation of cyclobutane pyrimidine dimers (CPDs). Various drugs have been reported to cause photosensitive drug eruptions as an adverse effect. Although the precise mechanism of photosensitive drug eruption remains to be elucidated, it is generally accepted that free radicals and other reactive molecules generated via UV‐irradiated drugs play important roles in the pathogenesis of photosensitive drug eruptions. The waveband of concern for photo‐reactive drugs is UVA‐visible light, but some extend into the UVB region. We tested whether photosensitive drugs could enhance CPD formation after UVA exposure by using isolated DNA in the presence of several reported photosensitive drugs using high‐performance liquid chromatography. We found that the diuretic agent hydrochlorothiazide (HCT) significantly enhanced the production of TT dimers over a wide range of UVA. Furthermore, we investigated whether UVA plus HCT could enhance CPD production in xeroderma pigmentosum model mice defective in nucleotide excision repair. Immunofluorescence studies showed that CPD formation in the skin significantly increased after 365 nm narrow‐band UVA irradiation in the presence of HCT, compared with that in wild‐type mice. HCT could be used with caution because of its enhancement of UVA‐induced DNA damage. 相似文献
84.
Synthesis of well-defined polystyrene with multi-functional end groups utilizing cyclotriphosphazene
Kenzo Inoue Sadao Negayama Tomoyuki Itaya Minoru Sugiyama 《Macromolecular rapid communications》1997,18(3):225-231
Telechelic polystyrenes with five benzyl chloride moieties at the polymer end (PSt-E) were prepared by coupling reaction of polystyryllithium with hexakis(4-chloromethyl-phenoxy)cyclotriphosphazene ( 4 ). The coupling reaction occurs almost quantitatively and unfavorable side reactions were not operative. When a mole ratio [ 4 ]/[sec-BuLi] = 9.3 was used, polystyrenes with cyclophosphazene carrying five benzyl chloride moieties at the polymer end (PSt-E) were obtained in more than 90% yield, which have narrow and predictable molecular weights (M w/M n = 1.05). A star shaped polystyrene with phosphazene core could also be prepared by using excess polystyryl anions. 相似文献
85.
An analytical method was established for the simultaneous determination of 39 polycyclic aromatic hydrocarbons (PAHs) in air. The method was applied to a survey of gaseous and particulate PAHs in household indoor air. The survey was performed in 21 houses in the summer of 1999 and in 20 houses in the winter of 1999-2000 in Fuji, Japan. Thirty-eight PAHs were determined in indoor and outdoor air in the summer, and 39 PAHs were determined in indoor and outdoor air in the winter. The concentrations of gaseous PAHs in indoor air tended to be higher than those in outdoor air in the summer and winter. The concentrations of particulate PAHs in indoor air were the same as or lower than those in outdoor air in the summer and winter. PAH profiles, correlations between PAH concentrations, and multiple regression analysis were used to determine the factors affecting the indoor PAH concentrations. These results showed that gaseous PAHs in indoor air were primarily from indoor emission sources, especially during the summer, and that indoor particulate PAH concentrations were significantly influenced by outdoor air pollution. 相似文献
86.
Nanometer-sized metallic palladium particles can be synthesized by hydrogen reduction of Pd2+ ions dissolved in the water core of a water-in-CO2 microemulsion. The Pd nanoparticles, stabilized by the micromeulsion and uniformly dispersed in the supercritical fluid phase, are effective catalysts for hydrogenation of olefins. Examples of rapid and efficient hydrogenation of water-soluble and CO2-soluble olefins catalyzed by the Pd nanoparticles in supercritical CO2 are given. 相似文献
87.
Rhodium nanoparticles dispersed by a CO2 microemulsion are effective catalysts for rapid hydrogenation of arenes in supercritical CO2. 相似文献
88.
Suzuki M Yumoto M Kimura M Shirai H Hanabusa K 《Chemical communications (Cambridge, England)》2002,(8):884-885
New L-lysine derivatives with a positively charged terminal can gel water below 1 wt%; particularly, 1a and 2a form a hydrogel at 0.3 wt% corresponding to approximately 12,300 and 12,500 waters/gelator molecule, respectively. 相似文献
89.
Ito S Sugiyama H Yoshifuji M 《Angewandte Chemie (International ed. in English)》2000,39(15):2781-2783
90.
Addition of diazomethane to 2-azido-2-alkenoates followed by pyrolysis of the resulting pyrazoline derivatives affords the title compounds. 相似文献