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791.
Minamide Y Osawa Y Nishida H Igarashi H Kudoh S 《Journal of separation science》2011,34(13):1590-1598
A highly sensitive simultaneous quantitative method for a cassette cold-microdosing study on celiprolol and atenolol was developed with liquid chromatography-tandem mass spectrometry. The method utilizes a combination of solid-phase extraction (SPE) with strong cation exchange (SCX) cartridge columns and reversed-phase chromatography with an ODS analytical column. SCX-SPE cartridge columns (100 mg sorbent) were used for a selective extraction of celiprolol, atenolol and metoprolol (internal standard) from 500 μL of human plasma samples. Turbo-ion spray at positive mode was employed for the ionization of the drug compounds. Quantitation was performed on a triple quadrupole mass spectrometer by selected reaction monitoring with the transitions of m/z 380 to m/z 251 for celiprolol and m/z 267 to m/z 145 for atenolol. Separation of analytes was achieved on an ODS column (100 mm length × 2.1 mm id, 3 μm) by a gradient elution with 10 mM formic acid and methanol by varying their proportion at a flow rate of 0.2 mL/min. The method was validated in the range of 1-250 pg/mL for celiprolol and 2.5-250 pg/mL for atenolol and was successfully applied to the elucidation of pharmacokinetic profiling in a cold cassette microdosing study of the β-blockers. 相似文献
792.
Hiroshi Ohrui Yoshihiro Nishida Hiroshi Hori Hiroshi Meguro Shoji Zushi 《Journal of carbohydrate chemistry》2013,32(4):711-731
Abstract 1-O-Methyl analogs of mucin oligosaccharide components, D-GalNAc (1a and 1b). β-D-Galp-(1-3)-D-GalNAc (2) and β-D-Galp(1-3)-[β-D-GlcNAc-(1-6)]-D-GalNAc (3) in which the H-6proS proton was selectively replaced by a deuterium, were synthesized to study the solution conformations about the C5-C6 fragments by 1H-NMR spectroscopy. The study revealed the preference of the gt-conformer for these sugars. 相似文献
793.
Dr. Shinsuke Nishida Dr. Junya Kawai Miki Moriguchi Tomohiro Ohba Naoki Haneda Dr. Kozo Fukui Prof. Akira Fuyuhiro Prof. Daisuke Shiomi Prof. Kazunobu Sato Prof. Takeji Takui Prof. Kazuhiro Nakasuji Prof. Yasushi Morita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(36):11904-11915
The tri‐tert‐butylphenalenyl (TBPLY) radical exists as a π dimer in the crystal form with perfect overlapping of the singly occupied molecular orbitals (SOMOs) causing strong antiferromagnetic exchange interactions. 2,5‐Di‐tert‐butyl‐6‐oxophenalenoxyl (6OPO) is a phenalenyl‐based air‐stable neutral π radical with extensive spin delocalization and is a counter analogue of phenalenyl in terms of the topological symmetry of the spin density distribution. X‐ray crystal structure analyses showed that 8‐tert‐butyl‐ and 8‐(p‐XC6H4)‐6OPOs (X=I, Br) also form π dimers in the crystalline state. The π‐dimeric structure of 8‐tert‐butyl‐6OPO is seemingly similar to that of TBPLY even though its SOMO–SOMO overlap is small compared with that of TBPLY. The 8‐(p‐XC6H4) derivatives form slipped stacking π dimers in which the SOMO–SOMO overlaps are greater than in 8‐tert‐butyl‐6OPO, but still smaller than in TBPLY. The solid‐state electronic spectra of the 6OPO derivatives show much weaker intradimer charge‐transfer bands, and SQUID measurements for 8‐(p‐BrC6H4)‐6OPO show a weak antiferromagnetic exchange interaction in the π dimer. These results demonstrate that the control of the spin distribution patterns of the phenalenyl skeleton switches the mode of exchange interaction within the phenalenyl‐based π dimer. The formation of the relevant multicenter–two‐electron bonds is discussed. 相似文献
794.
795.
Toshiyuki OhfusaAtsushi Nishida 《Tetrahedron》2011,67(10):1893-1906
Several bicyclic compounds were synthesized by the Diels-Alder reaction using aminodiene and a cyclic dienophile. The stereochemistries of the obtained adducts were determined by X-ray crystallography or NMR analysis. The stereoselectivity of this Diels-Alder reaction was based on the interaction of molecular orbitals between the diene and dienophile. The reactivities of these Diels-Alder reactions were estimated, and the generality of this reaction is discussed. 相似文献
796.
We have synthesized new electron-transporting oligothiophenes containing dicyanomethylene-substituted cyclopenta[b]thiophene as an active material for the fabrication of solution-processable n-type organic field-effect transistors (OFETs). The influence of the number of dicyanomethylene groups as well as the position of hexyl groups was investigated in detail by performing photophysical and electrochemical measurements. Results revealed that the optical energy gaps and the lowest unoccupied molecular orbital (LUMO) energy levels can be controlled by changing the number of dicyanomethylene groups. In contrast, the position of hexyl groups has little influence on molecular electronic properties. X-ray diffraction and atomic force microscopy measurements revealed that spin-coated thin films of the new compounds had a crystalline structure. OFETs based on these compounds were evaluated in vacuum and air-exposed conditions, and the electron mobility of up to 0.016 cm(2) V(-1) s(-1) was achieved. Furthermore, we demonstrated that the air stability of the OFETs depends on the LUMO energy level of the compounds. 相似文献
797.
O. Imamura B. Chen S. Nishida K. Yamashita M. Tsue M. Kono 《Proceedings of the Combustion Institute》2011,33(2):2005-2011
Flame is affected by an external electric field because it contains ions and electrons related to chemical reactions. On the other hand, the movement of ions and electrons affects the external electric field due to their charge. This paper reports the combustion experiments of ethanol droplets in vertical electric field with variable distance electrodes apparatus in order to discuss the change of the external electric field due to the existence of flame. From a one-dimensional steady-state analysis, if the electric field is changed spatially, its effect on combustion behavior is aligned with V2/L3 and not V/L, where V is the applied voltage between electrodes, and L is distance between the electrodes. The droplet is burned between the two horizontal parallel electrodes. The flame deformation and the electric current are characterized by various electrode distances, and respectively, applied voltages. The vertical electric field induces a body force downwards on the flame. The flame deforms downward in the electric field because the electric body force counters the natural buoyancy. The relation between the applied voltage and electrode distance is investigated when the flame becomes vertically symmetrical and the results show that the deformation is the function of V/L1.5. This indicates that the change in the electric field should be considered to discuss the effect of an external electric field on combustion behavior. The experimental results are rearranged using εV2/L3 where ε is electric permittivity of air because its unit is N/m3 and it considered to be the representative electric body force. Although its application is limited, qualitatively it can help to explain the experimental results of a droplet combustion. In addition, the degree of electron attachment to neutral molecules is discussed to interpret our experimental results. 相似文献
798.
Shiro Kubuki Hiroshi Sakka Kanako Tsuge Zoltán Homonnay Katalin Sinkó Ernő Kuzmann Hiroki Yasumitsu Tetsuaki Nishida 《Hyperfine Interactions》2008,185(1-3):115-121
Local structure and thermal durability of semiconducting xBaO·(90?? x)V2O5 · 10Fe2O3 glasses (x = 20, 30 and 40), NTA glass TM, before and after isothermal annealing were investigated by 57Fe-Mössbauer spectroscopy and differential thermal analysis (DTA). An identical isomer shift ( $\mathit{\delta}$ ) of 0.39 ± 0.01 mm s???1 and a systematic increase in the quadrupole splitting (Δ) were observed from 0.70 ± 0.02 to 0.80 ± 0.02 mm s???1 with an increasing BaO content, showing an increase in the local distortion of FeIIIO4 tetrahedra. From the slope of the straight line in the T g–Δ plot of NTA glass TM, it proved that FeIII plays a role of network former. Large Debye temperature (Θ D) values of 1000 and 486 K were respectively obtained for 20BaO · 70V2O5 · 10Fe2O3 glass before and after isothermal annealing at 400°C for 60 min, respectively. This result also suggests that FeIII atoms constitute the glass network composed of tetrahedral FeO4, tetrahedral VO4 and pyramidal VO5 units. The electric conductivity of 20BaO · 70V2O5 · 10Fe2O3 glass increased from 1.6 × 10???5 to 5.8 × 10???2 S cm???1 after isothermal annealing at 450°C for 2,000 min. These results suggest that the drastic increase in the electric conductivity caused by heat treatment is closely related to the structural relaxation of the glass network structure. 相似文献
799.
We investigate a two-species Fermi gas in which one species is confined in a two-dimensional plane (2D) or one-dimensional line (1D) while the other is free in the three-dimensional space (3D). We discuss the realization of such a system with the interspecies interaction tuned to resonance. When the mass ratio is in the range 0.0351相似文献
800.
Hongyang Zhao Hideo Kimura Zhenxiang Cheng Xiaolin Wang Kiyoshi Ozawa Takashi Nishida 《固体物理学:研究快报》2010,4(11):314-316
Single phase Bi2FeMnO6 films on (100) SrTiO3 substrate were fabricated using a pulsed laser deposition method through optimization of the preparation conditions. The magnetic moment is 0.30μB at 5 K in the magnetic field of 1 T, indicating that B site cations of Fe and Mn are disordered in the sample. The zero‐field‐cooling (ZFC) and field‐cooling (FC) magnetization curves measured from 2 K to 400 K coincide at 360 K. This is consistent with the observation that hysteresis disappears at 360 K, revealing the antiferromagnetic transition at this temperature. A spin‐glass‐like behaviour was observed at low temperature (~100 K) with a cusp of 25 K. Mn shows multiple valence states in the film. It is possibly because Mn2+ and Mn4+ could decrease the Jahn–Teller effect from Mn3+ in the film which results in less lattice distortion. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献