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51.
Kanae Sano Taiki Kuribara Nozomi Ishii Ayumi Kuroiwa Toshitada Yoshihara Seiji Tobita Kiichiro Totani Ichiro Matsuo 《化学:亚洲杂志》2019,14(11):1965-1969
Golgi endo‐α‐mannosidase (G‐EM) catalyzes an alternative deglucosylation process for N‐glycans and plays important roles in the post‐endoplasmic reticulum (ER) quality control pathway. To understand the post‐ER quality control mechanism, we synthesized a tetrasaccharide probe for the detection of the hydrolytic activity of G‐EM based on a fluorescence quenching assay. The probe was labeled with an N‐methylanthraniloyl group as a reporter dye at the non‐reducing end and a 2,4‐dinitrophenyl group as a quencher at the reducing end. This probe is hydrolyzed to disaccharide derivatives by G‐EM, resulting in increased fluorescence intensity. Thus, the fluorescence signal is directly proportional to the amount of disaccharide derivative present, allowing the G‐EM activity to be evaluated easily and quantitatively. 相似文献
52.
Kanae Hayashi Koichiro Hayashi Seizo Okamura 《Journal of polymer science. Part A, Polymer chemistry》1971,9(8):2305-2321
Radiation-induced free-ionic polymerization of isobutyl vinyl ether in bulk system has been studied by dilatometry and electrical conductivity measurement. Some refinements in kinetic treatment of estimate the propagation rate constant kp from the rate of polymerization and steady-state conductivity were attempted. Polymerization of superdried monomer which gave a half-power dose-rate dependence of Rp was carried out at 0, 25, and 50°C. The kp value obtained at 25°C and an activation energy for propagation were estimated as 1.2 ± 0.4 × 105 I./mole-sec and 9.6 ± 2.8 kcal/mole, respectively. In isobutyl vinyl ether, a propagation reaction in free-ionic mechanism was found to be characterized with a high frequency factor and presumably higher activation energy, compared with ion-pair mechanism. Discussions were also made as to several contrasting behaviors between the polymerization of alkyl vinyl ethers and other vinyl monomers as styrene both in free-ion and ion-pair mechanisms. 相似文献
53.
Yamada K Kato N Takagi A Koi M Hemmi H 《Analytical and bioanalytical chemistry》2005,382(7):1702-1707
Platinum (Pt)–DNA adducts formed by the anti-tumor agent cisplatin are recognized by the DNA mismatch repair (MMR) system. To investigate the involvement of MMR proteins including hMLH1 in the removal of these adducts, we developed a mL-scale wet-digestion method for inductively coupled plasma mass spectrometry (ICP-MS). The detection limit was 0.01 ng mL–1 Pt, which corresponded to 2 pg Pt/g DNA when 10 g of DNA was used. The mean relative errors were 5.4% or better for a dynamic range of 0.01–10 ng mL–1 Pt. DNA (~500 g) had no matrix effect. To improve the accuracy, DNA preparations were treated with ribonuclease and the apparent reduction in the concentration of Pt was corrected using cellular DNA levels, which were determined with Hoechst 33258. No significant differences were observed, in terms of the formation of Pt–DNA adducts or their removal over 6 h, between hMLH1-deficient HCT116 cells, a human colorectal cancer cell line, and hMLH1-complemented HCT116+ch3 cells (n=5; P>0.05), indicating that the hMLH1-dependent DNA repair systems contribute to neither the formation nor the removal of the adducts at detectable levels. In addition, approximately 19% of the adducts were removed within 6 h in both cell lines. A time course analysis (~24 h) suggested that the removal of cisplatin-generated Pt–DNA adducts follows first-order kinetics (t1/2=32 h). The amount of Pt–DNA adduct formed by oxaliplatin in 1 h was 56% (ratio of means) of that generated by an equimolar concentration of cisplatin in HCT116. The proposed procedure could be useful for determining Pt–DNA adducts formed by Pt(II) complexes. 相似文献
54.
Yao H Miki K Nishida N Sasaki A Kimura K 《Journal of the American Chemical Society》2005,127(44):15536-15543
We have succeeded for the first time in preparing a pair of gold nanocluster enantiomers protected by optically active thiols: D- and L-penicillamine (D-Pen and L-Pen). Circular dichroism (CD) spectroscopy confirmed the mirror image relationship between the D-Pen-capped and the L-Pen-capped gold nanoclusters, suggesting that the surface modifier acts as a chiral selector, and that the nanoclusters have well-defined stereostructures as common chiral molecules do. No CD signals could be obtained when the gold nanoclusters were synthesized by using a racemic mixture (rac-Pen). These chiroptical properties were investigated for the three separated fractions of each of the gold nanoclusters (D-Pen-capped, L-Pen-capped, or rac-Pen-capped clusters) by polyacrylamide gel electrophoresis (PAGE). Each fractioned component has the mean diameter of 0.57, 1.18, or 1.75 nm that was determined by a solution-phase small-angle X-ray scattering. With a decrease in the mean cluster diameter, optical activity or anisotropy factors gradually increased. On the basis of the kinetic and the structural considerations, the origins of large optical activity of the gold nanocluster enantiomers are discussed. 相似文献
55.
Teruyuki Hakoda Kanae Matsumoto Akira Mizuno Takuji Kojima Koichi Hirota 《Plasma Chemistry and Plasma Processing》2008,28(1):25-37
The oxidation of xylene and its irradiation byproducts in air using TiO2 was studied under electron beam (EB) irradiation for the purification of ventilation gases emitted from paint factories.
EB irradiation experiments were mainly performed under two different conditions: a TiO2 pellet layer was placed in an irradiation or a non-irradiation space. The results revealed that xylene was decomposed and
CO was formed in the gas phase of the irradiation space irrespective of the presence of TiO2 pellets, while CO2 was produced in the gas phase of the irradiation space and on the surface of TiO2 pellets. The total CO2 concentration increased when the pellet layer was in the non-irradiation space. On the other hand, the concentration of CO2 produced on the surface of the TiO2 pellets in the irradiation space was higher than that in a non-irradiation space. 相似文献
56.
Mitsuo Tsukiji Hiroyuki Kowa Kanae Muraki Norihiro Umeda Kenji Imoto Masayoshi Kanasaki Komei Tahara Katsunori Morii Yoshiro Tajitsu 《Macromolecular Symposia》2006,242(1):235-240
We produced a new system for measuring the small photoelastic constant of a polymer thin film with a small birefringence. Using our mesurement system, we evaluated the photoelastic constant of a polymer film in real time by quantitative analysis. Photoelastic constants of 11.30 × 10−12 Pa−1 for a cellulose triacetate film and 78.38 × 10−12 Pa−1 for a polycarbonate film were obtained. Furthermore, we obtained a small photoelastic constant of 0.12 × 10−12 Pa−1 for a cycloolefin film for liquid crystal displays, using our new measurement system. This value is very small. We emphasize that, if a small change in retardation and stress cannot be detected simultaneously using our system, then we cannot obtain such a small photoelastic constant. 相似文献
57.
Designer chiral quaternary ammonium bifluoride 1 has been prepared, and both its catalytic and its chiral efficiency have been clearly demonstrated by achieving the first catalytic asymmetric nitroaldol reaction of silyl nitronate with aldehydes. For instance, the reaction of trimethylsilyl nitronate 2 (R(1) = Me) with benzaldehyde (R(2) = Ph) in THF in the presence of (S,S)-1 (2 mol %) proceeded smoothly at -78 degrees C, giving the corresponding nitroaldol adduct 3 (R(1) = Me, R(2) = Ph) in 92% isolated yield (anti/syn = 92:8) with 95% ee (anti isomer). The method was found to be successfully applicable to other aromatic aldehydes and silyl nitronates, and a high level of anti selectivity and enantiomeric excess was constantly observed. This finding should lead to the further development of fluoride ion-catalyzed asymmetric carbon-carbon bond-forming reactions. 相似文献
58.
Kanae Hayashi Michhinori Tachibana Seizo Okamura 《Journal of polymer science. Part A, Polymer chemistry》1980,18(11):3297-3305
Bulk polymerization of chloroprene was studied at 25°C in a wide does rate range. Variations of the rate of polymerization (Rp) and molecular weight as a function of does rate were essentially the same as those in several monomers that are capab;e of radical and cationic polymerizations. The polymerization proceeds with radical mechanism at low dose rate ans with radical and cationic mechanism concurrently at high dose rate. The number-average molecular weight of the high-dose-rate was ca. 2400. Microstructure of the polymers was mainly of trans-1,4 unit with small fraction of cis-1,4 and 3,4-vinyl unit. Fractions of the vinyl unit and the inverted unit in trans-1,4 sequence which increased at high does rate inflected the change of dominant mechanism of polymerization. 相似文献
59.
A Comprehensive Study on Lyotropic Liquid–Crystalline Behavior of an Amphiphile in 20 Kinds of Amino Acid Ionic Liquids 下载免费PDF全文
Kanae Fujimura Dr. Takahiro Ichikawa Dr. Masafumi Yoshio Prof. Dr. Takashi Kato Prof. Dr. Hiroyuki Ohno 《化学:亚洲杂志》2016,11(4):520-526
We examined the self‐organization behavior of a designed amphiphilic molecule in 20 kinds of amino acid ionic liquids composed of 1‐butyl‐3‐methylimidazolium cation and natural amino acid anion ([C4mim][AA]). Addition of [C4mim][AA], regardless of their anion species, to the amphiphile provided homogeneous mixtures showing lyotropic liquid–crystalline (LC) behavior. Upon increasing the component ratio of [C4mim][AA] in the mixtures, a successive change of the mesophase patterns from inverted hexagonal columnar, in some case via bicontinuous cubic, to layered phases was observed. By examining the LC properties at various temperatures and component ratios, we constructed lyotropic LC phase diagrams. Interestingly, the appearance of these phase diagrams is greatly different according to the selection of [AA]. Through comparison, we found that the self‐organization behavior of an amphiphile in ionic liquids can be tuned by controlling their ability to form hydrogen‐bond, van der Waals, and π‐π interactions. 相似文献
60.
Hiromi Kitano Yasushi Maeda Kanae Furukawa Takahiro Yamamoto Rie Izumida Seiichi Matsugo 《Photochemistry and photobiology》1995,62(5):809-812
Abstract— -Modification of an enzyme, α-chymotrypsin, was examined by using a water-soluble photo-Fenton reagent. By photoirradiation of the enzyme with the reagent, which can occupy a binding site of the enzyme, a tryptophan residue in the vicinity of the active site was oxidized to N -formylkynurenine. Concurrently, the catalytic properties of the enzyme were largely changed: the K m was increased and the k cat was decreased. The decrease in k cat for a specific amide substrate was the most significant among the esters and amides examined. The water-soluble photo-Fenton reagent would be useful to chemically modify relatively limited regions in biomolecules. 相似文献