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951.
Oriented monoclinic WO3 thin films were fabricated by sol–gel method using aqueous sols of colloidal layered tungstates. The colloidal tungstate sols were prepared by reacting different alkylamines with layered tungstic acid H2WO4 in water. With decreasing the alkyl chain length of the alkylamines, the colloidal layered tungstate became smaller. Alkylamines with a short alkyl chain provided transparent aqueous sols. Furthermore, the WO3 thin films fabricated from the obtained aqueous sols had a high (100)-orientation. However, upon annealing H2WO4 crystals applied on a glass substrate with the tungstate layers parallel to the substrate, highly (001)-oriented WO3 layers were obtained. Since both of the A- and C-planes of WO3 have a similar structure to the layers of H2WO4, the orientation of the WO3 thin films and layers probably resulted from the topotactic structural conversion of the tungstates. Interestingly, the preferential orientation of the thin films was dependent on the presence or absence of interlayer alkylamines in the tungstates. 相似文献
952.
Toshinari Isono Takayuki Ikeda Ryuji Aoki Kenji Yamazaki Toshio Ogino 《Surface science》2010,604(21-22):2055-2063
Atomic force microscopy (AFM) was used to characterize morphology and chemistry on step-controlled single crystalline sapphire (0001) surfaces. Hydrophilicity on the surface can be evaluated using frictional force imaging. A sapphire surface that is covered with bunched steps accompanied with crossing steps clearly exhibits the phase-separation into two domains with different hydrophilicity, where an almost hydrophobic domain forms inside a hydrophilic area. By analyzing the histogram of the step height, we concluded that the difference in the hydrophilicity is associated with the surface reconstruction. We found that the phase-separation characterized by the hydrophilicity and charge potential self-organizes on the sapphire surface with specific step arrangements. We demonstrated selective adsorption of biomolecules on step-controlled surfaces as an example of the application. 相似文献
953.
Improvement in Solubility of Poorly Water Soluble Drug by Cogrinding with Highly Branched Cyclic Dextrin 总被引:1,自引:0,他引:1
Toshiro Fukami Takayuki Furuishi Toyofumi Suzuki Shinji Hidaka Haruhisa Ueda Kazuo Tomono 《Journal of inclusion phenomena and macrocyclic chemistry》2006,56(1-2):61-64
We investigated the enhancement of the solubility of glibenclamide (GCM), a poorly water soluble anti-diabetes drug, by cogrinding it with highly branched cyclic dextrin (HBCD) using a ball mill. Highly branched cyclic dextrin (HBCD) is a novel cyclic glucan produced from waxy corn starch by the cyclization reaction of a branching enzyme. When GCM crystals were coground with HBCD for 2 h, the solubility of GCM was improved to 12.4 μg/ml, while the concentration of HBCD was 5.0 mg/ml. Additionally, the GCM solubilized with HBCD was chemically stable in aqueous solution for at least 1 week at room temperature. The peak intensity assigned to crystalline GCM disappeared after cogrinding it by observing its powder X-ray diffraction pattern, which means that the crystalline structure of GCM could be disrupted. In the DSC measurement, the ground mixture showed a single endothermic peak, even though a temperature depression of the endothermic peak due to GCM crystal was observed. After the cogrinding, two sharp peaks assigned to sulfonylurea and benzoyl carbonyl stretching bands varied to broaden the peak to around 1640 cm−1 in the C=O stretching region. These results suggested the formation of solid dispersion between GCM and HBCD. 相似文献
954.
J.-I. Mizoguchi M. Takayuki S. Kashino 《Acta Crystallographica. Section C, Structural Chemistry》1997,53(11):IUC9700024-IUC9700024
955.
Water‐soluble Gd3+‐cored poly(ether amide) dendrimer complexes, bearing a diethylenetriaminepentaacetic acid Gd3+ complex (GdDTPA) core, were synthesized. The longitudinal proton relaxivity (R1), governed mainly by the rotation correlation time of the paramagnetic Gd3+ center, was measured in water (37 °C, 20 MHz). An anchor effect at the focal point of the hydrophilic dendrimer was experimentally evaluated for the first time, through a comparison of the R1 values with the ones reported for various Gd3+ complexes, including linear copolymers of GdDTPA linked by various lengths of aliphatic chains via amide bonds. Unusually large R1 values for the first‐ and second‐generation Gd3+‐cored dendrimer complexes (6.1 and 9.3 mM?1 s?1, respectively), even with relatively low molecular weights (1355 and 3877, respectively), suggested a remarkable increase in the local rigidity around the GdDTPA core. The internal rigidity of the dendrimer was supposed to take advantage of the increased nominal molecular weight in water via multihydration to the dendron to increase the rotation correlation time, and this resulted in the observed R1 gain. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2680–2689, 2004 相似文献
956.
Sungmin Kang Jirakorn Thisayukta Hideo Takezoe Junji Watanabe Kumiko Ogino Takayuki Doi Takashi Takahashi 《Liquid crystals》2004,31(10):1323-1336
Novel derivative series of the well known bent-shaped P-n-O-PIMB liquid crystal mesogens, referred to as '4Br-P-n-O-PIMB', '4Cl-P-n-O-PIMB' and '5Cl-P-n-O-PIMB', having halogen atoms substituted on the phenyl ring in the central core, were synthesized by solution phase parallel synthesis based on a combinatorial approach. The mesomorphic behaviour and physical properties of all the new compounds were studied by means of optical microscopy, differential scanning calorimetry, X-ray and circular dichroism spectroscopy. We found interesting transitional behaviour for the 4Br-P-n-O-PIMB homologous series. The homologues with alkyl tails having carbon numbers of n=3-10, 12, 14 exhibit rather complicated mesomorphic behaviour, which is strongly sensitive to n. The chiral fluid smectic B2 phase with SmCAPA structure and unidentified smectic Bx phase were observed in the homologues with n=9, 10, 12, 14 and n=3-5, respectively. Interestingly, every member exhibits frustrated and/or helical ordered phases at low temperatures, designated as X1, X2, and X3 phases, which result from a spontaneous escape from a macroscopic polarization. The mesomorphic behaviour and mesophase structures differ remarkably from those of the parent P-n-O-PIMB homologues, suggesting that substitution of the halogen atoms at the central core essentially creates a particular interaction between molecules. 相似文献
957.
M. Song K. Mitsuishi M. Tanaka M. Takeguchi M. Shimojo K. Furuya 《Applied Physics A: Materials Science & Processing》2005,80(7):1431-1436
Self-standing tungsten nanowires, nanodendrites, and nanofractal-like trees were fabricated on insulator (Al2O3) substrates with a process of electron-beam-induced decomposition in a transmission electron microscope. The conditions for fabricating different morphologies are described. The fabricated structures are characterized with high-resolution transmission electron microscopy and X-ray energy-dispersive spectroscopy. A high concentration of tungsten and a high crystallinity of the structure are confirmed. The growth process is discussed, involving charges produced on the surface of the substrate and the behavior of precursor molecules under electron-beam irradiation. The formation of these structures is considered to relate to nanoscaled unevenness of the charge distribution on the surface of the substrate, movement of charges to the convex surface of the substrate, and accumulation of charges at the tips of the grown structures. PACS 81.07.-b; 07.78.+s; 81.15.Gh; 81.16.-c 相似文献
958.
Dr. Koji Numasawa Prof. Kenjiro Hanaoka Naoko Saito Prof. Yoshifumi Yamaguchi Takayuki Ikeno Honami Echizen Dr. Masahiro Yasunaga Dr. Toru Komatsu Dr. Tasuku Ueno Prof. Masayuki Miura Prof. Tetsuo Nagano Prof. Yasuteru Urano 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(15):6071-6076
Folate receptors (FRs) are membrane proteins involved in folic acid uptake, and the alpha isoform (FR-α) is overexpressed in ovarian and endometrial cancer cells. For fluorescence imaging of FRs in vivo, the near-infrared (NIR) region (650–900 nm), in which tissue penetration is high and autofluorescence is low, is optimal, but existing NIR fluorescent probes targeting FR-α show high non-specific tissue adsorption, and require prolonged washout to visualize tumors. We have designed and synthesized a new NIR fluorescent probe, FolateSiR-1 , utilizing a Si-rhodamine fluorophore having a carboxy group at the benzene moiety, coupled to a folate ligand moiety through a negatively charged tripeptide linker. This probe exhibits very low background fluorescence and afforded a tumor-to-background ratio (TBR) of up to 83 in FR-expressing tumor-bearing mice within 30 min. Thus, FolateSiR-1 has the potential to contribute to the research in the field of biology and the clinical medicine. 相似文献
959.
Kinetic Resolution of Allyl Fluorides by Enantioselective Allylic Trifluoromethylation Based on Silicon‐Assisted CF Bond Cleavage
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960.
Inside Cover: Kinetic Resolution of Allyl Fluorides by Enantioselective Allylic Trifluoromethylation Based on Silicon‐Assisted CF Bond CleavageZ308071 (Angew. Chem. Int. Ed. 2/2014)
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