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91.
The electroreductive intramolecular coupling of aliphatic cyclic imides with ketones in isopropanol gave five- and six-membered cyclized products. Similarly, the electroreductive intramolecular coupling of aliphatic cyclic imides with O-methyloximes afforded five-, six-, and seven-membered cyclized products. These reactions provide a useful method to synthesize azabicyclo[n.m.0] compounds. The bicyclic products were stereoselectively transformed to the corresponding deoxylated compounds by reduction with NaB(CN)H3 or Et3SiH/BF3·Et2O. 相似文献
92.
Plínio C. Sathler Charles S. Craik Toshihiko Takeuchi Russolina B. Zingali Helena C. Castro 《Applied biochemistry and biotechnology》2010,160(8):2355-2365
Ecotin is a bidentate, fold-specific inhibitor of mammalian serine-proteases produced by Escherichia coli. This molecule may be engineered to increase and/or change its affinity and specificity providing significant biotechnological
potential. Since ecotin binds tightly to serine proteases of the trypsin fold, it may help to identify the role of these enzymes
in different biological processes. In this work, we tested ecotin variants as an affinity purification reagent for identifying
enzymes in samples of tumor progression and mammary gland involution. Initially, we used a commercial source of urokinase-type
plasminogen activator (u-PA) that remained fully active after elution from an affinity column of the ecotin variant (M84R,
M85R). We then successfully identified u-PA from more complex mixtures including lysates from a prostate cancer cell line
and involuting mouse mammary glands. Interestingly, a membrane-type serine protease 1 was isolated from the Triton X-100-solubilized
PC-3 cell lysates, and surprisingly, haptoglobin, a serine-protease homolog protein, was also identified in mammary gland
lysates and in blood. Haptoglobin does not prevent ecotin inhibition of u-PA, but it may act as a carrier within blood when
ecotin is used in vivo. Finally, this affinity purification matrix was also able to identify a thrombin-like enzyme from snake venom using an ecotin
variant directed against thrombin. Overall, the ecotin variants acted as robust tools for the isolation and characterization
of proteins with a trypsin fold. Thus, they may assist in the understanding of the role of these serine proteases and homologous
proteins in different biological processes. 相似文献
93.
94.
Toshihiko Ueki Matsumi Doe Yoshiki Morimoto Takamasa Kinoshita Rika Tanaka Kazuo Yoshihara 《Journal of heterocyclic chemistry》2001,38(1):165-172
Hyperolactones A ( 1 ) and C ( 3 ) have been synthesized starting from (S)‐malic acid by a straightforward route. The unique spirolactone skeleton was efficiently constructed by one‐pot reaction as a key step. The absolute stereochemistry of hyperolactones was unambiguously established by this synthesis. 相似文献
95.
Tomohiko Sato Toshihiko Nakaoka Makoto Kudo Yasuhiko Arakawa 《Physica E: Low-dimensional Systems and Nanostructures》2006,32(1-2):152
We have investigated magneto-optical properties of GaSb/GaAs self-assemble type II quantum dots by single dot spectroscopy in magnetic field. We have observed clear Zeeman splitting and diamagnetic shift of GaSb/GaAs quantum dots. The diamagnetic coefficient ranges from 5 to 30 μeV/T2. The large coefficient and their large distribution are attributed to the size inhomogeneity and electron localization outside the dot. The g-factor of GaSb/GaAs quantum dots is slightly larger than that of similar type I InGaAs/GaAs quantum dots. In addition, we find almost linear relationship between the diamagnetic coefficient and the g-factor. The linear increase of g-factor with diamagnetic coefficient is due to an increase of spin-orbit interaction with dot size. 相似文献
96.
The characteristics and applicability of the absorption spectroscopy system using the coherent transition radiation light source have been investigated. The configurations of the system are relatively simple. The operational conditions of an electron linear accelerator have been evaluated. The stability of the light intensity has been within ±2–3% in a wavenumber range of 4–13 cm−1. The light intensity has been found to be more than six orders of magnitude higher than that for the lowest limit for detection. 相似文献
97.
98.
Daisuke Adachi Kohei Takei Toshihiko Toyama Hiroaki Okamoto 《Applied Surface Science》2007,254(1):299-302
Effects of ZnS:Mn/AlN multilayer structure on luminescent properties of nanostructured (NS) thin-film electroluminescent (TFEL) device of which emission layer is a multilayer composed with ZnS:Mn layers and 0.7-nm-thick AlN interlayers were studied. The bandgap widening and the increased PL efficiency of Mn2+ 3d-3d transitions with a decrease in the ZnS:Mn single-layer thickness down to 5 nm were observed, which is ascribed to quantum confinement effects. Meanwhile, the multilayer with 2-nm-thick ZnS:Mn single-layers shows a drop of PL efficiency, indicating the presence of defective region just on AlN. The tendency of the luminous efficiency of the NS-TFEL device against the ZnS:Mn single-layer thickness is similar to the tendency found in the PL efficiency, indicating the importance of the ZnS:Mn/AlN interface for the device performance. 相似文献
99.
100.
Yu Ding Ruggero Micheletto Hiroaki Hanada Toshihiko Nagamura Satoshi Okazaki Koji Otsuka 《Optical Review》2002,9(6):277-281
This work describes a groundbreaking process that provides a direct highly localized measurement of the atomic mass on surfaces at room temperature. Employing an original system that joins a scanning tunneling microscopy (STM) device and a time of flight (TOF) mass analyzer, we could previously ionize surface atoms by the combination of an optical laser pulse and an electric pulse at the STM tip. Desorbed ions from a localized area were accelerated and detected by a TOF chamber. We will demonstrate in this paper that high localization and mass discrimination can be obtained even without the aid of an electric pulse from the tip. We reduced the angle of incidence of the laser beam to zero (laser beam parallel to the sample surface). In this condition we were able to demonstrate for the first time ionic desorption at a confinement level of the order of 5-10nm, an order of magnitude better than previous configurations.This paper was originally presented at the 11th Optical Near Field Workshop, which was held on June 28, 2002 at Tokyo Institute of Technology, Yokohama, organized by the Optical Near Field Group of the Optical Society of Japan, an affiliate of the Japan Society of Applied Physics. 相似文献