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101.
A novel pressure-driven sample injection method was developed as an alternative to electrokinetic injection, and electrophoretic separation was carried out on a microfabricated device employing this method. This method enables a defined volume of liquid dispensing, followed by instantaneous injection driven by pneumatic pressure, greatly simplifying the injection procedure. A particular microstructure, called a "metering chamber", has been designed for the quantitative dispensing of an ultra-low volume of sample liquid; a "hydrophobic passive valve" equipped with an air vent channel is employed for injecting a dispensed sample into the separation channel. The reproducibility of dispensing was 3.3% (n = 15), expressed by the variation of dispensed volumes. The electrophoretic separation of DNA fragments was performed using this injection method, varying the injection volumes from 0.45 to 4.0 nL, and the separation efficiencies were compared. This precise injection method, easily variable in injection volumes, is highly suitable for quantitative as well as qualitative electrophoretic analyses. 相似文献
102.
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104.
Michiko Kodama Mika Kuwabara SyÛZÔ Seki 《Molecular Crystals and Liquid Crystals》2013,570(9-10):277-282
Differential scanning calorimetry on the two-component system of dioctadecyldimethylammonium chloride (DOAC)–water was carried out in the temperature region from 80 °C down to -100 °C. As the result, a new type of glassy state was found around at -40 °C for the supercooled complete gel phase. 相似文献
105.
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
106.
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
107.
Prof. Dr. Yasuchika Hasegawa Takafumi Matsui Dr. Yuichi Kitagawa Dr. Takayuki Nakanishi Dr. Tomohiro Seki Prof. Dr. Hajime Ito Prof. Dr. Yuta Nakasaka Prof. Dr. Takao Masuda Prof. Dr. Koji Fushimi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(53):12308-12315
Oxygen-sensitive and near-infrared (NIR) luminescent YbIII coordination polymers incorporating ligands based on pyrene derivatives were synthesized: YbIII–TBAPy and YbIII–TIAPy (TBAPy: 1,3,6,8-tetrakis(p-benzoate)pyrene; TIAPy: 1,3,6,8-tetrakis(3,5-isophthalic acid)pyrene). The coordination structures of these materials have been characterized by means of electrospray ionization mass spectrometry, X-ray diffraction analysis, and thermogravimetric analysis. Moreover, the porous structure of YbIII–TIAPy has been evaluated by measuring its N2 adsorption isotherm. The NIR luminescence properties of YbIII–TBAPy and YbIII–TIAPy have been examined by acquiring emission spectra and determining emission lifetimes under air or argon and in vacuo. YbIII–TIAPy exhibited high thermal stability (with a decomposition temperature of 400 °C), intense luminescence (with an emission quantum yield under argon of 6.6 %), and effective oxygen-sensing characteristics. These results suggest that NIR luminescent YbIII coordination polymers prepared using pyrene derivatives could have applications in novel thermo-stable oxygen sensors. 相似文献
108.
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
109.
Direct Introduction of a Dimesitylboryl Group Using Base‐Mediated Substitution of Aryl Halides with Silyldimesitylborane
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Dr. Eiji Yamamoto Kiyotaka Izumi Ryosuke Shishido Prof. Dr. Tomohiro Seki Noriaki Tokodai Prof. Dr. Hajime Ito 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(49):17547-17551
The first dimesitylboryl substitution of aryl halides with a silylborane bearing a dimesitylboryl group in the presence of alkali‐metal alkoxides is described. The reactions of aryl bromides or iodides with Ph2MeSi?BMes2 and Na(OtBu) afforded the desired aryl dimesitylboranes in good to high yields and with high borylation/silylation ratios. Selective reaction of the sterically less‐hindered C?Br bond of dibromoarenes provided monoborylated products. This reaction was used to rapidly construct a D‐π‐A aryl dimesityl borane with a non‐symmetrical biphenyl spacer. 相似文献
110.
The structure of 1,4,8,11-tetraazacyclotetradecane (cyclam) complexes with nickel(II) and copper(II) ions in aqueous solution has been determined by the x-ray diffraction method at 25°C. The [Ni-(cyclam)]2+ complex has a square-planar structure with four nitrogen atoms of the cyclam, and the Ni-N bond length has been determined to be 198 pm. Upon the addition of ammonia, the color of the nickel(II)-cyclam solution turns to deep purple and the [Ni(NH3)2(cyclam)]2+ complex is formed. The complex has a regular octahedral structure with an additional two NH3 molecules along the axis vertical of the cyclam plane, and the Ni-N (NH3 and cyclam) bond lengths are 209 pm. The copper(II)-cyclam complex in the aqueous solution is a distorted octahedron with two water molecules along the elongated axis. The axial Cu—O and equatorial Cu—N bond lengths are 277 and 210 pm, respectively. 相似文献