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111.
112.
Yutaka Maniwa Yoshinori Kumazawa Yumi Saito Hideki Tou Hiromichi Kataura Hiroyoshi Ishii 《Molecular Crystals and Liquid Crystals》2013,570(1):671-676
Abstract X-ray diffraction (XRD) and electrical resistance measurement on single-walled carbon nan-otube (SWNT) samples prepared by the arc-discharge method are reported. The XRD profile of heat-treated sample indicated that air (oxygen, and/or nitrogen and/or water) can be condensed inside the SWNTs. We also found that the electrical resistance of SWNT soot is significantly affected by exposing to the oxygen gas and humid air. 相似文献
113.
Tatsuhiko Nagao Daichi Yukihira Yoshinori Fujimura Kazunori Saito Katsutoshi Takahashi Daisuke Miura Hiroyuki Wariishi 《Analytica chimica acta》2014
In mass spectrometry (MS)-based metabolomics studies, reference-free identification of metabolites is still a challenging issue. Previously, we demonstrated that the elemental composition (EC) of metabolites could be unambiguously determined using isotopic fine structure, observed by ultrahigh resolution MS, which provided the relative isotopic abundance (RIA) of 13C, 15N, 18O, and 34S. Herein, we evaluated the efficacy of the RIA for determining ECs based on the MS peaks of 20,258 known metabolites. The metabolites were simulated with a ≤25% error in the isotopic peak area to investigate how the error size effect affected the rate of unambiguous determination of the ECs. The simulation indicated that, in combination with reported constraint rules, the RIA led to unambiguous determination of the ECs for more than 90% of the tested metabolites. It was noteworthy that, in positive ion mode, the process could distinguish alkali metal-adduct ions ([M + Na]+ and [M + K]+). However, a significant degradation of the EC determination performance was observed when the method was applied to real metabolomic data (mouse liver extracts analyzed by infusion ESI), because of the influence of noise and bias on the RIA. To achieve ideal performance, as indicated in the simulation, we developed an additional method to compensate for bias on the measured ion intensities. The method improved the performance of the calculation, permitting determination of ECs for 72% of the observed peaks. The proposed method is considered a useful starting point for high-throughput identification of metabolites in metabolomic research. 相似文献
114.
115.
Yoshiki Horikawa Naoya Konakahara Tomoya Imai Abe Kentaro Yoshinori Kobayashi Junji Sugiyama 《Polymer Degradation and Stability》2013
The enzymatic hydrolysis of cellulose I achieves almost complete digestion when sufficient enzyme loading as much as 20 mg/g-substrate is applied. However, the yield of digestion reaches the limit when the enzyme dosage is decreased to 2 mg/g-substrate. Therefore, we have performed three pretreatments such as mercerization, dissolution into phosphoric acid and EDA treatment. Transformation into cellulose II hydrate by mercerization and dissolution into phosphoric acid were not sufficient because substrate changed to highly crystalline structure during saccharification. On the other hand, in the case of crystalline conversion of cellulose I to IIII by EDA, almost perfect digestion was achieved even in enzyme loading as small as 0.5 mg/g-substrate, furthermore, hydrolyzed residue was typical cellulose I. The structural analysis of substrate after saccharification provides an insight into relationships between cellulose crystalline property and cellulase toward better enzymatic digestion. 相似文献
116.
Masami Kuriyama Satoko Tanigawa Yuki Kubo Yosuke Demizu Osamu Onomura 《Tetrahedron: Asymmetry》2010,21(11-12):1370-1373
A facile synthetic method toward optically active 3,3-disubstituted oxindoles with excellent enantioselectivity was achieved using chiral copper-catalyzed desymmetrization of prochiral 1,3-diols. The monotosylated product was transformed into oxindole derivatives efficiently. 相似文献
117.
Kazuyuki Kubo Hiroshi Nakazawa Hiroyasu Inagaki Tomoyuki Miyake Tsutomu Mizuta Katsuhiko Miyoshi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8-9):2159-2160
Treatment of [Cp*(CO) 2 M{P(NHPh)(OMe) 2 }]PF 6 (M = Fe and Ru) with NaNH 2 gives metallaiminophosphoranes, Cp*(CO) 2 M{P(NPh)(OMe) 2 }. The x-ray structures and reactivity of the complexes are reported. 相似文献
118.
Tatsuro Ouchi Hiroshi Sakamoto Masayasu Kubo Yoshifumi Hosaka Minoru Imoto 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(2):111-123
The radical polymerization of vinyl monomers initiated with several kinds of hydrophilic macromolecule was carried out in a magnetic field. The magnetic field promoted the polymerization; the conversion of monomers and the molecular weight of the polymers obtained increased with increasing field strength in the range of 0–0.1 T. The dependence of the composition and tacticity of the mother polymer on the magnitude of the magnetic field was studied. Using graft or block copolymers, which consisted of hard and soft segments, the effect of a magnetic field was further investigated. The degree of hardness and tightness of the hydrophobic areas (reaction areas) formed by the mother polymer in the aqueous solution was found to affect the magnetic field effect on the uncatalyzed polymerization. The overall activation energy obtained in the magnetic field was almost equal to that obtained without a magnetic field. 相似文献
119.
Yew-Hong Ooi Chun-Chieh Han Hong-Cheu Lin Kenji Kubo Masato M. Ito 《Liquid crystals》2013,40(4):516-527
A series of symmetrical trimeric liquid crystalline compounds of which the molecular structure with a central core of 1,3,5-benzene attached by three rod-like mesogenic Schiff base moieties via the propylene spacers and ether linkages has successfully been synthesised and characterised by infra red and nuclear magnetic resonance spectroscopic techniques. All the star-shaped compounds in this series exhibit predominantly SmC phase except the analogue possessing terminal C8H17 group. It is apparent that the members with even parity from C10H21 to C16H33 show enantiotropic SmC phase while the member with longest terminal chain of C18H37 is inclined to monotropic smectogen. The X-ray diffraction measurements reveal that the tilted smectic layer structures of the SmC phase are confirmed to have an obvious sharp peak at small angles of 2θ ~ 1.03°–1.48° with d-spacing values of 4.01–4.58 nm, which are corresponding to tilt angles of ~48° in the SmC phase. 相似文献
120.
Nobutaka Yamaoka Kohei Sumida Itsuki Itani Hiroko Kubo Yusuke Ohnishi Sho Sekiguchi Dr. Toshifumi Dohi Prof. Dr. Yasuyuki Kita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(44):15004-15011
Metal‐free oxidative C? C coupling by using polyalkoxybenzene‐derived diaryliodonium(III) salts as both the oxidant and aryl source has been developed. These salts can induce single‐electron‐transfer (SET) oxidation to yield electron‐rich arenes and subsequently transfer the polyalkoxyphenyl group into in situ generated aromatic radical cations to produce biaryl products. The reaction is promoted by a Lewis acid that activates the iodonium salts. It has been revealed that the reactivity of the salts under acidic conditions is quite different to their known behavior under basic conditions. The reactivity preference of a series of iodonium salts in the SET oxidation and their ligand transfer abilities have been systematically investigated and the results are summarized in this report. 相似文献