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51.
Takako Yamaguchi Emi Amano Shinichiro Kamino Satoko Umehara Chizuko Yanaihara Yoshikazu Fujita 《Analytical sciences》2005,21(10):1237-1240
A simple and sensitive spectrophotometric method for the determination of human serum albumin (HSA) was established based on the ternary complex-formation reaction of HSA with o-sulfophenylfluorone (SPF) as a xanthene dye and metal ion (niobium(V) and bismuth(III)) in the presence of a dispersion agent. This new method enabled the determination of HSA in the range of 1 - 15 microg/ml HSA by measuring the difference of the absorbance at 530 nm between HSA-SPF-metal ion and SPF-metal ion solutions. In the determination of HSA, this method is about 2-times more sensitive than the Pyrogallol Red-molybdenum(VI) method (PR method), which accounts for more than 80% of the quantification methods for urinary protein assays in Japan. There was no significant difference between the results obtained by the present method and the PR method for human urine samples. The binding process between the SPF-metal complex and HSA was studied by determining the binding parameters and the thermodynamic parameters. 相似文献
52.
Eri Hatano Prof. Dr. Masakazu Morimoto Dr. Kengo Hyodo Dr. Nobuhiro Yasuda Prof. Dr. Satoshi Yokojima Dr. Shinichiro Nakamura Prof. Dr. Kingo Uchida 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(36):12680-12683
Crystals of a diarylethene with a perfluorocyclohexene ring exhibit a remarkable photosalient effect upon UV light irradiation that is attributed to the structural changes that occur when going from open‐ to closed‐ring isomers in the crystalline state, together with the existence of two conformers with different photoconversions compared with those of a perfluorocyclopentene derivative. Our current results give a design principle for molecular structures so as to achieve the photosalient effect for photochromic crystals. 相似文献
53.
The Design,Synthesis, and Evaluation of 1,5,7‐Trisubstituted‐3‐Pyridyl‐Xanthones for Use as Insecticides Starting from Pyripyropene A
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Dr. Shinichiro Fuse Keisuke Matsumura Dr. Kohei Johmoto Dr. Hidehiro Uekusa Dr. Hiroshi Tanaka Dr. Tomoyasu Hirose Prof. Dr. Toshiaki Sunazuka Prof. Dr. Satoshi Ōmura Prof. Dr. Takashi Takahashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18450-18455
A readily accessible template of 1,5,7‐trisubstituted‐3‐pyridyl‐xanthones was designed starting from naturally occurring pyripyropene A for agrichemical development. Our originally developed Ag2CO3‐mediated oxidative cyclization enabled ready access to the key scaffold, 1,5,7‐trihydroxy‐3‐chloro‐xanthone. The chemo‐ and regioselective sequential introduction of four substituents to the scaffold rapidly afforded the desired, structurally diverse 1,5,7‐trisubstituted‐3‐pyridyl‐xanthones. An evaluation of insecticidal activity revealed that one of the synthesized compounds retained insecticidal activity against vetch aphid and green peach aphid. The observed insecticidal spectrum was similar to that of pyripyropene A. The developed template could be a valuable aid for future agrichemical development. 相似文献
54.
Kitamura Noritaka Imai Nobuaki Haba Hiromitsu Michimasa Shin’ichiro Shimoura Susumu Yamaguchi Yuki 《Journal of Radioanalytical and Nuclear Chemistry》2021,330(3):721-725
Journal of Radioanalytical and Nuclear Chemistry - The nuclear isomer $$^{178}$$ Hfm2 enables various investigations owing to its unique properties. To study exotic nuclear reactions induced by... 相似文献
55.
56.
The α‐Glycosidation of Partially Unprotected N‐Acetyl and N‐Glycolyl Sialyl Donors in the Absence of a Nitrile Solvent Effect
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Taku Aoyagi Dr. Shuichi Ohira Dr. Shinichiro Fuse Dr. Jun Uzawa Dr. Yoshiki Yamaguchi Dr. Hiroshi Tanaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(20):6968-6973
The synthesis of α‐sialosides is one of the most difficult reactions in carbohydrate chemistry and is considered to be both a thermodynamically and kinetically disfavored process. The use of acetonitrile as a solvent is an effective solution for the α‐selective glycosidation of N‐acetyl sialic acids. In this report, we report on the α‐glycosidation of partially unprotected N‐acetyl and N‐glycolyl donors in the absence of a nitrile solvent effect. The 9‐O‐benzyl‐N‐acetylthiosialoside underwent glycosidation in CH2Cl2 with a good α‐selectivity. On the other hand, the 4,7,8‐O‐triacetyl‐9‐O‐benzyl‐N‐acetylthiosialoside was converted to β‐sialoside as a major product under the same reaction conditions. The results indicate that the O‐acetyl protection of the sialyl donor was a major factor in reducing the α‐selectivity of sialylation. After tuning of the protecting groups of the hydroxy groups at the 4,7,8 position on the sialyl donor, we found that the 9‐O‐benzyl‐4‐O‐chloroacetyl‐N‐acetylthiosialoside underwent sialylation with excellent α‐selectivity in CH2Cl2. To demonstrate the utility of the method, straightforward synthesis of α(2,9) disialosides containing N‐acetyl and/or N‐glycolyl groups was achieved by using the two N‐acetyl and N‐glycolyl sialyl donors. 相似文献
57.
58.
Masaaki Hori Mariko Yoshida Kazumasa Yokoyama Koji Kamagata Fumitaka Kumagai Issei Fukunaga Kouhei Kamiya Michimasa Suzuki Yoshitaka Masutani Nozomi Hamasaki Yuriko Suzuki Shinsuke Kyogoku Nobutaka Hattori Shigeki Aoki 《Magnetic resonance imaging》2014
Introduction
Diffusion tensor imaging (DTI) reveals white matter pathology in patients with multiple sclerosis (MS). A recent non-Gaussian diffusion imaging technique, q-space imaging (QSI), may provide several advantages over conventional MRI techniques in regard to in vivo evaluation of the disease process in patients with MS. The purpose of this study is to investigate the use of root mean square displacement (RMSD) derived from QSI data to characterize plaques, periplaque white matter (PWM), and normal-appearing white matter (NAWM) in patients with MS.Methods
We generated apparent diffusion coefficient (ADC) and fractional anisotropy (FA) maps by using conventional DTI data from 21 MS patients; we generated RMSD maps by using QSI data from these patients. We used the Steel–Dwass test to compare the diffusion metrics of regions of interest in plaques, PWM, and NAWM.Results
ADC differed (P < 0.05) between plaques and PWM and between plaques and NAWM. FA differed (P < 0.05) between plaques and NAWM. RMSD differed (P < 0.05) between plaques and PWM, plaques and NAWM, and PWM and NAWM.Conclusion
RMSD values from QSI may reflect microstructural changes and white-matter damage in patients with MS with higher sensitivity than do conventional ADC and FA values. 相似文献59.
Yuma Otake Yusuke Shibata Yoshihiro Hayashi Susumu Kawauchi Hiroyuki Nakamura Shinichiro Fuse 《Angewandte Chemie (International ed. in English)》2020,59(31):12925-12930
The development of a robust amide‐bond formation remains a critical aspect of N‐methylated peptide synthesis. In this study, we synthesized a variety of dipeptides in high yields, without severe racemization, from equivalent amounts of amino acids. Highly reactive N‐methylimidazolium cation species were generated in situ to accelerate the amidation. The key to success was the addition of a strong Brønsted acid. The developed amidation enabled the synthesis of a bulky peptide with a higher yield in a shorter amount of time compared with the results of conventional amidation. In addition, the amidation can be performed by using either a microflow reactor or a conventional flask. The first total synthesis of naturally occurring bulky N‐methylated peptides, pterulamides I–IV, was achieved. Based on experimental results and theoretical calculations, we speculated that a Brønsted acid would accelerate the rate‐limiting generation of acyl imidazolium cations from mixed carbonic anhydrides. 相似文献
60.
β‐Amino acid N‐carboxy anhydrides (β‐NCAs) are rarely used in the synthesis of β‐peptides, which is due mainly to the poor availability of these potentially useful substrates. Herein, we describe the heretofore challenging synthesis of β‐NCAs via a single‐step, rapid, and mild formation using pH flash switching and flash dilution, which are aspects of micro‐flow technology. We synthesized 15 β‐NCAs in good to excellent yields that included acid‐labile β‐NCAs that cannot be readily synthesized using the conventional Leuchs approach. Scaled‐up synthesis using this process can be readily achieved via continuous operation. 相似文献