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141.
Hirofumi Yamamoto Yuichi Takagi Naoto Yamasaki Tadashi Mitsuyama Yusuke Kasai Hiroshi Imagawa Yutaro Kinoshita Naohiro Oka Masanori Hiraoka 《Tetrahedron》2018,74(50):7173-7178
Thallusin is the only known natural product that induces cell differentiation followed by formation of a thallus during the growth of green macroalgae such as Monostroma and Ulva. Herein, various thallusin analogues based on the terpen skeleton were synthesized to study the structure?activity relationships of thallusin. The potency of the synthetic analogues was investigated in an experimental assay, which demonstrated that the 19-methyl group in thallusin is essential for potent morphogenesis-inducing activity. 相似文献
142.
Masanori Morishita Fumio Kawamura Minoru Kawahara Masashi Yoshimura Yusuke Mori Takatomo Sasaki 《Journal of Crystal Growth》2004,270(3-4):402-408
The dependency of LPE growth rate and dislocation density on supersaturation in the growth of GaN single crystals in the Na flux was investigated. When the growth rate was low during the growth of GaN at a small value of supersaturation, the dislocation density was much lower compared with that of a substrate grown by the Metal Organic Chemical Vapor Deposition method (MOCVD). In contrast, when the growth rate of GaN was high at a large value of supersaturation, the crystal was hopper including a large number of dislocations. The relationship between the growth conditions and the crystal color in GaN single crystals grown in Na flux was also investigated. When at 800 °C the nitrogen concentration in Na–Ga melt was low, the grown crystals were always tinted black. When the nitrogen concentration at 850 °C was high, transparent crystals could be grown. 相似文献
143.
Kozaburo Tamura Shinya Hosokawa Masanori Inui Makoto Yao Hirohisa Endo Hideoki Hoshino 《Journal of Non》1992,150(1-3):351-355
Extended X-ray absorption fine structure (EXAFS) spectra from liquid As2Se3 around both the As and Se K-edges in the temperature-pressure range up to 1400°C and about 60 bar were measured. For the EXAFS measurements, a new type of high pressure vessel and a sample cell of own design made of polycrystalline sapphire were developed. Distinct EXAFS oscillations were obtained even at 1400°C. When the semiconductor-to-metal transition occurs at about 1000°C, the local environment around a central As atoms is substantially changes and a new As neighbor site is induced. 相似文献
144.
Mozer AJ Wagner P Officer DL Wallace GG Campbell WM Miyashita M Sunahara K Mori S 《Chemical communications (Cambridge, England)》2008,(39):4741-4743
Electron lifetime and diffusion coefficient measurements in highly efficient porphyrin-sensitised TiO(2) solar cells showed reduced electron lifetime, and consequently, lower photo-induced electron density under illumination compared to commonly used ruthenium dye (N719)-sensitised solar cells, which is proposed to be the origin of the generally lower open circuit voltage. 相似文献
145.
A novel mediator-polymer-modified anode for microbial fuel cells 总被引:1,自引:0,他引:1
Adachi M Shimomura T Komatsu M Yakuwa H Miya A 《Chemical communications (Cambridge, England)》2008,(17):2055-2057
A high-performance anode system based on a combination of mediator-polymer-modified graphite felt and bacteria capable of reducing extracellular materials shows significant potential for practical use in microbial fuel cells (MFCs). 相似文献
146.
147.
Kang JH Kuramoto M Tsuchiya A Toita R Asai D Sato YT Mori T Niidome T Katayama Y 《European journal of mass spectrometry (Chichester, England)》2008,14(4):261-265
To identify the correlation between the phosphorylation ratios by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-ToF MS) analysis and enzyme kinetics (K(m), V(max), and V(max)/K(m)) is important to understand whether MALDI-TOF MS can be applied for monitoring the properties of peptides that are substrates of protein kinases. The correlation between phosphorylation ratios and enzyme kinetics was examined using peptides for protein kinase C (PKC) and for 60 kDa phosphoprotein, encoded by the cellular sarcoma gene (c-Src). Phosphorylation ratios, analyzed by MALDI-ToF MS, showed higher correlation coefficient (r = > +0.7) for V(max)/K(m) compared with that (r = < -/+0.6) for K(m) or V(max). For ion modes, a higher correlation coefficient between phosphorylation ratios and V(max)/K(m) was identified in the positive mode (r = > +0.7) compared to that in the negative mode (r = < +0.5). These results suggest that MALDI-ToF MS is a useful tool to evaluate V(max)/K(m) of peptides for protein kinases. 相似文献
148.
149.
Yamaji M Cai X Sakamoto M Fujitsuka M Majima T 《The journal of physical chemistry. A》2008,112(45):11306-11311
Photochemical properties of p-phenylphenacyl derivatives (PP-X) having C-halide, C-S, and C-O bonds in the lowest (T 1) and higher (T n ) triplet excited states were investigated in solution by using single-color and stepwise two-color two-laser flash photolysis techniques. PP-Xs (X = Br, SH, and SPh) undergo beta-bond dissociation in the lowest singlet excited states (S 1) while the C-X bonds of other PP-Xs are stable upon 266-nm laser photolysis. The T 1(pi,pi*) states of PP-X were efficiently produced during 355-nm laser photolysis of benzophenone as a triplet sensitizer. Triplet PP-Xs deactivate to the ground state without photochemical reactions. Upon 430-nm laser photolysis of the T 1 states of PP-X (X = Br, Cl, SH, SPh, OH, OMe, and OPh), decomposition of PP-X in the T n states was found. On the basis of the changes in the transient absorption, quantum yields (Phi dec) of the decomposition of PP-X in the T n states were determined, while bond dissociation energies (BDE) of the C-X bonds were calculated by computations. According to the relationship between the Phi dec and BDE values, it was shown that the decomposition of PP-X in the T n state is due to beta-cleavage of the corresponding C-X bond, and that the state energy of the reactive T n for the C-O bond cleavage differs from that for the C-halide and C-S bond cleavage. The reaction profiles of the C-X bond cleavage of PP-X in the T n states were discussed. 相似文献
150.
Dr. Yusuke Imamura Kyohei Takaoka Yuma Komori Dr. Masanori Nagatomo Prof. Dr. Masayuki Inoue 《Angewandte Chemie (International ed. in English)》2023,62(10):e202219114
Taxol is a clinically used drug for the treatment of various types of cancers. Its 6/8/6/4-membered ring (ABCD-ring) system is substituted by eight oxygen functional groups and flanked by four acyl groups, including a β-amino acid side chain. Here we report a 34-step total synthesis of this unusually oxygenated and intricately fused structure. Inter- and intramolecular radical coupling reactions connected the A- and C-ring fragments and cyclized the B-ring, respectively. Functional groups of the A- and C-rings were then efficiently decorated by employing newly developed chemo-, regio-, and stereoselective reactions. Finally, construction of the D-ring and conjugation with the β-amino acid delivered taxol. The powerful coupling reactions and functional group manipulations implemented in the present synthesis provide new valuable information for designing multistep target-oriented syntheses of diverse bioactive natural products. 相似文献