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781.
Tomoya Ueda Daiki Murakami Masaru Tanaka 《Journal of polymer science. Part A, Polymer chemistry》2021,59(22):2763-2770
In this study, a blood-compatible polymer, poly(2-methoxyethyl acrylate) (PMEA), was grafted onto a gold substrate with various grafting densities (σ) (σ = 0–0.18 chains nm−2), and the amount of hydrated water and mobility of the polymer chain interacting with water molecules were quantitatively evaluated using a quartz crystal microbalance with an admittance system. The amount of hydrated water decreased with increasing σ. By contrast, the mobility of the hydrated PMEA was maximum at σ ≈ 0.12 chains nm−2, revealing that the amount of high-mobility water at σ = 0.12 was higher than that at other densities. The degree of denaturation of the adsorbed fibrinogen was evaluated based on the hydrodynamic water ratio and viscoelasticity, and was found to increase with increasing σ. The denaturation of adsorbed fibrinogen was suppressed when both the amount of hydrated water and the mobility of hydrated PMEA were high. This study demonstrates that the interfacial state of the polymer chains hydrated in water is important for blood compatibility. 相似文献
782.
Masaru Yoshida 《Chemical record (New York, N.Y.)》2010,10(4):230-242
In this article, novel gel‐forming materials based on oligomeric and polymeric electrolytes for not only water but also organic solvents, including ionic liquids, are highlighted especially the synthesis, derivatization, and physical property. The oligoelectrolytes with cationic pyridinium backbone can be very easily prepared by the intermolecular quaternization of the ampholytic monomer. The ionene polymers with N,N′‐(p‐phenylene)dibenzamide linkages as polyelectrolyte were also straightforwardly synthesized in high yields by the copolymerization of 1,4‐bis[4‐(chloromethyl)benzamide]benzene and commercially available α,ω‐ditertiary amines. The oligo‐ and polyelectrolytes provided physical hydrogels under ca. 1–5 wt% of the concentrations after heating and cooling at room temperature without any other additives. These cationic gelators have characteristic properties, such as acid resistance, a self‐healing nature after mechanical collapse, and a dispersant ability for single‐walled carbon nanotubes, which have been rarely attainable for conventional physical gelators. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 230–242; 2010: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.201000007 相似文献
783.
Several (azido)iridium(III) complexes having a pentamethylcyclopentadienyl (Cp∗) group, [Cp∗Ir(N3)2(Ph2Ppy-κP)] (1: Ph2Ppy = 2-diphenylphosphinopyridine), [Cp∗Ir(N3)(Ph2Ppy-κP,κN)]CF3SO3 (2), [Cp∗Ir(N3)(dmpm)]PF6 (3: dmpm = bis(dimethylphosphino)methane), [Cp∗Ir(N3)(Ph2Pqn)]PF6·CH3OH (4·CH3OH: Ph2Pqn = 8-diphenylphosphinoquinoline), and [Cp∗Ir(N3)(pybim)] (5: Hpybim = 2-(2-pyridyl)benzimidazole) have been prepared and their crystal structures have been analyzed by X-ray diffraction. In complex 1, the Ph2Ppy ligand is only coordinated via the P atom (-κP), while in 2 it acts as a bidentate ligand through the P and N atoms (-κP,κN) to form a four-membered chelate ring. Comparing the structural parameters of the chelate ring in 2 with those of a similar five-membered chelate ring formed by Ph2Pqn in 4, it became apparent that the angular distortion in the Ph2Ppy-κP,κN ring was remarkable, although the Ir–P and Ir–N bonds in the Ph2Ppy-κP,κN ring were not elongated very much from the corresponding bonds in the Ph2Pqn-κP,κN ring. In the pybim complex 5, the five-membered chelate ring was coplanar with the pyridine and benzimidazolyl rings. With the related (azido)iridium(III) complexes analyzed previously, comparison of the structural parameters of the Ir–N3 moiety in [Cp∗IrIII(N3)(L–L′)]+/0 complexes reveals an anomalous feature of the 2,2′-bipyridyl (bpy) complex, [Cp∗Ir(N3)(bpy)]PF6. 相似文献
784.
Takekazu Ishida Kohei Arai Yukio Akita Mitsunori Miyanari Yusuke Minami Tsutomu Yotsuya Masaru Kato Kazuo Satoh Mayumi Uno Hisashi Shimakage Shigehito Miki Zhen Wang 《Physica C: Superconductivity and its Applications》2010,470(19):730-733
The nanofabrication of superconductors yields various interesting features in superconducting properties. A variety of different imaging techniques have been developed for probing the local superconducting profiles. A scanning pulsed laser microscope has been developed by the combination of the XYZ piezo-driven stages and an optical fiber with an aspheric focusing lens. The scanning laser microscope is used to understand the position-dependent properties of a superconducting MgB2 stripline of length 100 μm and width of 3 μm under constant bias current. Our results show that the superconducting stripline can clearly be seen in the contour image of the scanning laser microscope on the signal voltage. It is suggested from the observed image that the inhomogeneity is relevant in specifying the operating conditions such as detection efficiency of the sensor. 相似文献
785.
786.
Dr. Masaru Fujibayashi Yu Watari Dr. Ryo Tsunashima Prof. Sadafumi Nishihara Prof. Shin-ichiro Noro Dr. Chang-Gen Lin Prof. Yu-Fei Song Dr. Kiyonori Takahashi Prof. Takayoshi Nakamura Prof. Tomoyuki Akutagawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(50):22632-22636
The structural phase of a metal oxide changes with temperature and pressure. During phase transitions, component ions move in multidimensional metal–oxygen networks. Such macroscopic structural events are robust to changes in particle size, even at scales of around 10 nm, and size effects limiting these transitions are particularly important in, for example, high-density memory applications of ferroelectrics. In this study, we examined structural transitions of the molecular metal oxide [Na@(SO3)2(n-BuPO3)4MoV4MoVI14O49]5− (Molecule 1 ) at approximately 2 nm by using single-crystal X-ray diffraction analysis. The Na+ encapsulated in the discrete metal-oxide anion exhibited a reversible order–disorder transition with distortion of the Mo–O molecular framework induced by temperature. Similar order–disorder transitions were also triggered by chemical pressure induced by removing crystalline solvent molecules in the single-crystal state or by substituting the countercation to change the molecular packing. 相似文献
787.
Ryu Hashimoto Dr. Masafumi Minoshima Dr. Junichi Kikuta Shinya Yari Prof. Steven D. Bull Prof. Masaru Ishii Prof. Kazuya Kikuchi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(47):21182-21186
A rationally designed pH-activatable fluorescent probe (pHocas-RIS) has been used to measure localised pH levels in osteocytic lacunae in bone tissue. Conjugation of the moderate bone-binding drug risedronate to a pH-activatable BODIPY fluorophore enables the probe to penetrate osteocytic lacunae cavities that are embedded deep within the bone matrix. After injection of pHocas-RIS, any osteocytic lacunae caused by bone-resorbing osteocytes cause the probe to fluoresce in vivo, thus allowing imaging by intravital two-photon excitation microscopy. This pH responsive probe enabled the visualization of the bone mineralizing activities of acid producing osteocytes in real time, thus allowing the study of their central role in remodeling the bone-matrix in healthy and disease states. 相似文献
788.
Construction of a Triangle‐Shaped Trimer and a Tetrahedron Using an α‐Helix‐Inserted Circular Permutant of Cytochrome c555 下载免费PDF全文
Akiya Oda Dr. Satoshi Nagao Dr. Masaru Yamanaka Ikki Ueda Dr. Hiroki Watanabe Prof. Dr. Takayuki Uchihashi Dr. Naoki Shibata Prof. Dr. Yoshiki Higuchi Prof. Dr. Shun Hirota 《化学:亚洲杂志》2018,13(8):964-967
Highly‐ordered protein structures have gained interest for future uses for biomaterials. Herein, we constructed a building block protein (BBP) by the circular permutation of the hyperthermostable Aquifex aeolicus cytochrome (cyt) c555, and assembled BBP into a triangle‐shaped trimer and a tetrahedron. The angle of the intermolecular interactions of BBP was controlled by cleaving the domain‐swapping hinge loop of cyt c555 and connecting the original N‐ and C‐terminal α‐helices with an α‐helical linker. We obtained BBP oligomers up to ≈40 mers, with a relatively large amount of trimers. According to the X‐ray crystallographic analysis of the BBP trimer, the N‐terminal region of one BBP molecule interacted intermolecularly with the C‐terminal region of another BBP molecule, resulting in a triangle‐shaped structure with an edge length of 68 Å. Additionally, four trimers assembled into a unique tetrahedron in the crystal. These results demonstrate that the circular permutation connecting the original N‐ and C‐terminal α‐helices with an α‐helical linker may be useful for constructing organized protein structures. 相似文献
789.
Yadolah Ganjkhanlou Zdeněk Tišler José Miguel Hidalgo Karel Frolich Jiří Kotera Pavel Čičmanec Roman Bulánek 《Chemical Papers》2018,72(4):937-946
Effect of zirconium presence in the silica framework and content and speciation of vanadium surface oxo-complexes on the catalytic behavior of VOx/Zr–SBA-15 catalysts in oxidative dehydrogenation of ethanol was investigated. Experimental results bring evidence of successful incorporation of zirconium into ordered mesoporous silica framework with the preservation of ordered mesoporosity by hydrothermal template base synthesis method. The presence of zirconium in the SBA-15 framework increases reducibility of vanadium species and acidity of the catalysts. It is reflected in higher activity of vanadium species expressed as turn-over frequency (e.g., TOF of 20 h?1 for 5%VOx/Zr–SBA-15 sample in comparison with TOF of 12 h?1 for 5%VOx/SBA-15 sample) and also in significant decrease of selectivity to acetaldehyde (65% in comparison with 90% for mentioned samples) followed by increase in selectivity to ethylene (25% in comparison with 5%). This change in distribution of reaction products is related to stronger acidity character of surface OH groups and inhibition effect of formed water vapours on the oxidative dehydrogenation products (acetaldehyde). Catalytic data also reveal that oligomeric/polymeric tetrahedrally coordinated vanadium species exhibit higher activity in ethanol oxidative dehydrogenation than monomeric complexes. In addition, comparison of the catalytic performance of VOx/Zr–SBA-15 catalysts with VOx/SBA-15 catalysts showed that catalytic properties of VOx/Zr–SBA-15 catalysts can be tuned by incorporation of controlled amount of zirconium into silica framework. 相似文献
790.
Yoshihiro Maruyama Masaru Joe Fuse Takeshi Yokomori Ryo Ohmura Shigeru Watanabe Toru Iwasaki Wataru Iwabuchi Toshihisa Ueda 《Proceedings of the Combustion Institute》2013,34(2):2131-2138
Flame spreading over pure methane hydrate in a laminar boundary layer is investigated experimentally. The free stream velocity (U∞) was set constant at 0.4 m/s and the surface temperature of the hydrate at the ignition (Ts) was varied between ?10 and ?80 °C. Hydrate particle sizes were smaller than 0.5 mm. Two types of flame spreading were observed; “low speed flame spreading” and “high speed flame spreading”. The low speed flame spreading was observed at low temperature conditions (Ts = ?80 to ?60 °C) and temperatures in which anomalous self-preservation took place (Ts = ?30 to ?10 °C). In this case, the heat transfer from the leading flame edge to the hydrate surface plays a key role for flame spreading. The high speed flame spreading was observed when Ts = ?50 and ?40 °C. At these temperatures, the dissociation of hydrate took place and the methane gas was released from the hydrate to form a thin mixed layer of methane and air with a high concentration gradient over the hydrate. The leading flame edge spread in this premixed gas at a spread speed much higher than laminar burning velocity, mainly due to the effect of burnt gas expansion. 相似文献