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991.
S Akatsu Y Kanematsu TA Kurihara S Sueyoshi Y Arikawa M Onishi S Ishizaka N Kitamura Y Nakao S Sakaki K Umakoshi 《Inorganic chemistry》2012,51(15):7977-7992
Heteropolynuclear Pt(II) complexes with 3,5-diphenylpyrazolate [Pt(2)Ag(4)(μ-Cl)(2)(μ-Ph(2)pz)(6)] (3), [Pt(2)Ag(2)Cl(2)(μ-Ph(2)pz)(4)(Ph(2)pzH)(2)] (4), [Pt(2)Cu(2)Cl(2)(μ-Ph(2)pz)(4)(Ph(2)pzH)(2)] (5), [Pt(2)Ag(4)(μ-Cl)(μ-Me(2)pz)(μ-Ph(2)pz)(6)] (7), and [Pt(2)Ag(4)(μ-Me(2)pz)(2)(μ-Ph(2)pz)(6)] (8) have been prepared and structurally characterized. These complexes are luminescent except for 5 in the solid state at an ambient temperature with emissions of red-orange (3), orange (4), yellow-orange (7), and green (8) light, respectively. Systematic red shift of the emission energies with the number of chloride ligands was observed for 3, 7, and 8. DFT calculations indicate that the highest occupied molecular orbital (HOMO) as well as HOMO-1 of the heterohexanuclear complexes, 3, 7, and 8, having Pt(2)Ag(4) core, mainly consist of dδ orbital of Pt(II) and π orbitals of Ph(2)pz ligands, while the lowest unoccupied molecular orbital (LUMO) of these complexes mainly consists of in-phase combination of 6p of two Pt(II) centers and 5p of four Ag(I) centers. It is likely that the emissions of 3, 7, and 8 are attributed to emissive states derived from the Pt(2)(d)/π → Pt(2)Ag(4) transitions, the emission energy of which depends on the ratio of chloride ligands to pyrazolate ligands. 相似文献
992.
Kajihara Y Tanabe Y Sasaoka S Okamoto R 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(19):5944-5953
The N-glycosylation of proteins is generated at the consensus sequence NXS/T (where X is any amino acid except proline) by the biosynthetic process, and occurs in the endoplasmic reticulum and Golgi apparatus. In order to investigate the influence of human complex-type oligosaccharides on counterpart protein conformation, crambin and ovomucoide, which consist of 46 and 56 amino acid residues, respectively, were selected for synthesis of model glycoproteins. These small glycoproteins were intentionally designed to be glycosylated at the α-helix (crambin: 8?position), β-sheet (crambin: 2?position) and loop position between the antiparallel β-sheets (ovomucoide: 28?position), and were synthesized by using a peptide-segment coupling strategy. After preparation of these glycosylated polypeptide chains, protein folding experiments were performed under redox conditions by using cysteine-cystine. Although the small glycoproteins bearing intentional glycosylation at the α-helix and β-sheet exhibited a suitable folding process, glycosylation at the loop position between the antiparallel β-strands caused multiple products. The conformational differences in the isolated homogeneous glycoproteins compared with non-glycosylated counterparts were evaluated by circular dichroism (CD) and NMR spectroscopy. These analyses suggested that this intentional N-glycosylation did not result in large conformational changes in the purified protein structures, including the case of glycosylation at the loop position between the antiparallel β-strands. In addition to these experiments, the conformational properties of three glycoproteins were evaluated by CD spectroscopy under different temperatures. The oligosaccharides on the protein surface fluctuated considerably; this was dependent on the increase in the solution temperature and was thought to disrupt the protein tertiary structure. Based on the measurement of the CD spectra, however, the glycoproteins bearing three disulfide bonds did not exhibit any change in their protein tertiary structure. These results suggest that the oligosaccharide conformational fluctuations were not disruptive to protein tertiary structure, and the tertiary structure of glycoproteins might be stabilized by the disulfide bond network. 相似文献
993.
Hara N Nakamura S Sano M Tamura R Funahashi Y Shibata N 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(30):9276-9280
The organocatalytic enantioselective decarboxylative addition of malonic acid half thioesters to ketimines derived from isatins by using N-heteroarenesulfonyl cinchona alkaloid amides afforded products with high enantioselectivity. The products could be converted into optically active AG-041R. X-ray crystallographic analysis revealed that the hydrogen bonding between the sulfonimide proton and the 8-quinolyl nitrogen atom plays an important role in exerting the enantioselectivity of the reaction. 相似文献
994.
Yamaguchi Y Ouchi Y 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2012,88(4):152-166
Defensins comprise a family of cationic antimicrobial peptides containing a specific six-cysteine motif. Their contribution to the host defense against microbial invasion and the control of normal flora have been previously described. Some of the β-defensin isoforms are predominantly expressed in the epididymis and showed a region-specific expression pattern in the epididymis, which thus suggested that these isoforms may possess epididymis-specific functions in addition to antimicrobial activities. A sequence variant of the β-defensin 126 gene has been shown to be associated with reductions in the human sperm function, thus supporting this hypothesis. Furthermore, defensins have the capacity to chemoattract immune cells and induce the secretion of inflammatory cytokines. Mice expressing human neutrophil α-defensin showed more severe lung injuries after the aspiration of acidic contents than did control mice. Recent investigations regarding copy number variations of human defensin genes also suggest the significance of defensin in the pathogenesis or the worsening of chronic obstructive pulmonary diseases, sepsis and psoriasis. 相似文献
995.
Yasuhiro Abe 《Nuclear Physics B》2012,854(1):193-242
We consider generalization of the Cachazo-Svrcek-Witten (CSW) rules to one-loop amplitudes of N=4 super Yang-Mills theory in a recently developed holonomy formalism in twistor space. We first reconsider off-shell continuation of the Lorentz-invariant Nair measure for the incorporation of loop integrals. We then formulate an S-matrix functional for general amplitudes such that it implements the CSW rules at quantum level. For one-loop MHV amplitudes, the S-matrix functional correctly reproduces the analytic expressions obtained in the Brandhuber-Spence-Travaglini (BST) method. Motivated by this result, we propose a novel regularization scheme by use of an iterated-integral representation of polylogarithms and obtain a set of new analytic expressions for one-loop NMHV and N2MHV amplitudes in a conjectural form. We also briefly sketch how the extension to one-loop non-MHV amplitudes in general can be carried out. 相似文献
996.
Y Tobu R Ikeda TA Nihei K Gotoh H Ishida T Asaji 《Physical chemistry chemical physics : PCCP》2012,14(35):12347-12354
The temperature dependence of (35)Cl NQR frequencies and the spin-lattice relaxation times T(1) has been measured in the wide temperature range of 4.2-420 K for morpholinium hydrogen chloranilate in which a one-dimensional O-HO hydrogen-bonded molecular chain of hydrogen chloranilate ions is formed. An anomalous temperature dependence of the NQR frequencies was analyzed to deduce a drastic temperature variation of the electronic state of the hydrogen-bonded molecular chain. The hydrogen atom distribution in the OHO hydrogen bond is discussed from the results of NQR as well as multi-temperature X-ray diffraction. Above ca. 330 K, the T(1) showed a steep decrease with an activation energy of ca. 70 kJ mol(-1) and with an isotope ratio (37)Cl T(1)/(35)Cl T(1) = 0.97 ± 0.2. The orientational change of the z axis of electric field gradient tensor in conjunction with the hydrogen transfer between adjacent hydrogen chloranilate ions is suggested as a possible relaxation mechanism. 相似文献
997.
Harding JR Lu YC Tsukada Y Shao-Horn Y 《Physical chemistry chemical physics : PCCP》2012,14(30):10540-10546
The oxidation kinetics of Li(2)O(2) was studied in a carbonate-free electrolyte using electrodes consisting of non-catalyzed and catalyzed Vulcan carbon (VC) and chemically synthesized Li(2)O(2) particles. VC and Au nanoparticles supported on VC (Au/C) were fairly inactive for catalyzing the oxidation of Li(2)O(2), where oxidation currents greater than 10 mA g(carbon)(-1) were found only at voltages equal to and greater than 4.0 V vs. Li (V(Li)). Pt and Ru nanoparticles supported on VC (Pt/C and Ru/C) could significantly increase the kinetics of Li(2)O(2) oxidation, where Li(2)O(2) could be removed largely at voltages below 4 V(Li). In addition, Pt/C and Ru/C showed quick initiation of Li(2)O(2) oxidation in contrast to VC and Au/C. 相似文献
998.
Non-acoustical and acoustical properties of reticulated and partially reticulated polyurethane foams
A series of measurements on four polyurethane foam samples with pore membranes and a polyurethane foam sample without pore membranes have been made. Tortuosity has been deduced using the ultrasonic slope method. It has been found that the deduced value of tortuosity depends on the measurement temperature and for two of the polyurethane foam samples with many pore membranes physically meaningful values of tortuosity cannot be obtained at a temperature of around 25 °C. However more realistic values of tortuosity have been obtained by from measurements at or around the glass transition temperature of polyurethane foam (i.e. at ?20 °C) when using the ultrasonic slope method.Flow resistivity, Young’s moduli and loss factors have been measured also.Vibration of the pore membranes has been observed to influence the effective density and characteristic impedance derived from the surface impedance measured in an impedance tube. This paper discusses relationships between membrane vibration and the slow and fast compressional waves. The relative merits of predictions based on rigid-porous models and the Biot–Johnson–Champoux–Allard model are discussed also. 相似文献
999.
Kenji Yoshii Ignace Jarrige Chikashi Suzuki Daiju Matsumura Yasuo Nishihata Yasuhiro Yoneda Tatsuo Fukuda Kazuhisa Tamura Yoshiaki Ito Takeshi Mukoyama Tatsunori Tochio Hiroshi Shinotsuka Sei Fukushima 《Journal of Physics and Chemistry of Solids》2012,73(9):1106-1110
We have directly probed the Ba 5d states in the ferroelectric barium titanate BaTiO3 using two bulk-sensitive spectroscopic probes, resonant x-ray emission spectroscopy (RXES) and x-ray absorption spectroscopy in the partial fluorescence mode (PFY-XAS) at the Ba-L3 edge. The results are compared with those of the non-ferroelectric barium sulfate BaSO4. While the RXES spectra point to a localized character for the Ba 5d states in both compounds, the main peak of the PFY-XAS spectrum, corresponding to the dipolar transitions from 2p to 5d, is found to be significantly broader for BaTiO3 than for BaSO4. On the basis of band structure calculations, this broadening is ascribed to strong hybridization between the unoccupied Ba 5d and O 2p states in the ferroelectric. This suggests that the hybridization between the conduction states of the Ba2+ and O2? ions, and not only Ti4+ and O2?, plays a central role in determining the electronic structure of BaTiO3, and is therefore likely to be indirectly correlated with the occurrence of ferroelectricity in this material. 相似文献
1000.
Arikawa Y Matsumoto N Asayama T Umakoshi K Onishi M 《Dalton transactions (Cambridge, England : 2003)》2011,40(10):2148-2150
The hydroxido-bridged dinuclear ruthenium complex 4, which is supported by Tp ligands, has been prepared from protonation of the oxido-bridged dinuclear ruthenium complex 3. Additional protonation of 4, affording the aqua-bridged dinuclear ruthenium complex 5 in situ, and subsequent treatment with NO gave rise to the dicationic dinitrosyl complex 2. These indicate completion of the NO reduction cycle on the dinuclear ruthenium complex. 相似文献