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521.
Hidekazu Tanaka Keigo Ishida Takeshi Okumiya Masahiko Murakami 《Colloid and polymer science》2010,288(14-15):1427-1433
Titanium butyl phosphates (TiBP) synthesized by reacting Ti(SO4)2 with a mixture of mono-(C4H9PO4H2) and dibutyl phosphates ((C4H9)2PO4H) in aqueous ethanol solution at 25 °C were characterized by various conventional techniques. XRD pattern of TiBP possessed a peak at 2θ?=?5.5° and a broad hump at 2θ?=?15–30°. This fact indicated that the material was composed of a multilayer alternating bilayer of butyl groups of the phosphates and amorphous titanium phosphate phase. The TiBP was spherical particles with a size of ca. 100 nm and the chemical formula of this material was Ti((C4H9O)2PO2)x(C4H9OPO3)y(OH)z. The TiBP possessed a UV absorption property due to charge transfer of O2? ? Ti4+. The layered structure of TiBP was exfoliated in ethanol at 25 °C up to TiBP concentration of 1.0?×?105 ppm to form nanosheet. The nanosheet dispersing solution exhibited a UV absorption property and the property depends on nanosheet concentration. 相似文献
522.
Yuka Ikemoto Michio Ishikawa Satoru Nakashima Hidekazu Okamura Yuichi Haruyama Shinji Matsui Taro Moriwaki Toyohiko Kinoshita 《Optics Communications》2012,285(8):2212-2217
We report the status of a scattering near-field microspectroscopy apparatus developed at SPring-8 using an infrared synchrotron radiation (IR-SR) source. It consists of a scattering type scanning near-field optical microscope and a Fourier transform infrared spectrometer. The IR-SR is used as a highly brilliant and broad-band IR source. This apparatus has potential for application in near-field spectroscopy with high spatial resolution beyond the diffraction limit. In order to eliminate background scatterings from the probe shaft and/or sample surface, we used higher harmonic demodulation method. The near-field spectra were observed by 2nd harmonic components using the lock-in detection. The spatial resolution of about 300 nm was achieved at around 1000 cm? 1 (10 μm wavelength). 相似文献
523.
The catalytic activity of bovine serum albumin (BSA) modified physically by molecular imprinting using transition-state analogue (TSA) as a template molecule was studied. The resultant imprinted serum albumin (Imp-BSA) showed the rate acceleration of dehydrofluorination reaction from (4R,4S)-4-fluoro-4-(4-nitrophenyl)butan-2-one ( 1 ) and followed the type of Michaelis-Menten reaction in ethyl acetate solution. The enzymatic activity of Imp-BSA was competitively inhibited by (4R,4S)-4-hydroxy-4-(4-nitrophenyl)butan-2-one ( 4 ). 相似文献
524.
Shiro Kobayashi Hidekazu Morii Ryosuke Ito Masashi Ohmae 《Macromolecular Symposia》2002,183(1):127-132
Artificial hyaluronic acid has been synthesized in vitro via enzymatic polymerization catalyzed by testicular hyaluronidases, which is the first successful example of the hyaluronic acid synthesis via non-biosynthetic pathways. The novel GlcAβ(1→3)GlcNAc oxazoline derivative was designed and synthesized as a transition state analogue monomer for the hyaluronidase catalysis. The oxazoline monomer was efficiently recognized by the enzymes at pH 7.1 to 9.0 and the polymerization reaction proceeded in a regio- and stereo-selective manner to give rise to artificial hyaluronic acid with molecular weight higher than 15000. These results strongly suggest that the transition state of these testicular hyaluronidases catalysis corresponds to a sugar oxazolinium ion. 相似文献
525.
Polylactide, which is a biodegradable and bio‐absorbable polymer having low immunogenicity and good biocompatibility, has been mainly studied for biomedical applications. Branched polymers have different rheological and mechanical properties compared with their linear counterparts owing to their molecular architectures. We synthesized novel biodegradable polylactide having a branched structure composed of metabolically degradable and/or absorbable materials only. The branched polylactide was obtained from a one‐pot copolymerization of L ‐lactide using metabolic intermediate dl ‐mevalonolactone as a bifunctional comonomer having both lactone ring and pendant hydroxy group. The glass transition point, melting point and crystallinity of the branched polylactide are lower than those of linear polylactide. 相似文献
526.