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51.
Niidome Y Honda K Higashimoto K Kawazumi H Yamada S Nakashima N Sasaki Y Ishida Y Kikuchi J 《Chemical communications (Cambridge, England)》2007,(36):3777-3779
Colloidal gold nanorods (GNRs), which were passivated with cationic cerasome-forming lipids having triethoxysilyl groups, were obtained in the aqueous phase by sonication of the mixture of lipids and GNRs. 相似文献
52.
Kanako Nakamae Dr. Yukie Takemura Dr. Bunsho Kure Prof. Takayuki Nakajima Prof. Yasutaka Kitagawa Prof. Tomoaki Tanase 《Angewandte Chemie (International ed. in English)》2015,54(3):1016-1021
A linear tetraphosphine, meso‐bis[(diphenylphosphinomethyl)phenylphosphino]methane (dpmppm) was used to synthesize linear octapalladium‐extended metal atom chains as discrete molecules of [Pd8(μ‐dpmppm)4](BF4)4 ( 1 ) and [Pd8(μ‐dpmppm)4L2](BF4)4 (L=2,6‐xylyl isocyanide (XylNC; 2 ), acetonitrile ( 3 ), and N,N‐dimethylformamide (dmf; 4 )), which are stable in the solution states and show interesting temperature‐dependent photochemical properties in the near IR region. Variable temperature NMR studies demonstrated that at higher temperature T≈140 °C the Pd8 chains were dissociated into Pd4 fragments, which were thermodynamically self‐aligned to restore the Pd8 chains at lower temperature T<60 °C. The coldspray ionization mass spectra suggested a possibility for further aggregation of the linear tetrapalladium units. 相似文献
53.
Ohtaka A Teratani T Fujii R Ikeshita K Kawashima T Tatsumi K Shimomura O Nomura R 《The Journal of organic chemistry》2011,76(10):4052-4060
Linear polystyrene-stabilized PdO nanoparticles (PS-PdONPs) were prepared in water by thermal decomposition of Pd(OAc)(2) in the presence of polystyrene. The immobilization degree of palladium was dependent on the molecular weight of polystyrene, while the size of the Pd nanoparticles was not. Linear polystyrene-stabilized Pd nanoparticles (PS-PdNPs) were also prepared using NaBH(4) and phenylboronic acid as reductants. The catalytic activity of PS-PdONPs was slightly higher than that of PS-PdNPs for Suzuki coupling reaction in water. PS-PdONPs exhibited high catalytic activity for Suzuki and copper-free Sonogashira coupling reactions in water and recycled without loss of activity. 相似文献
54.
Toyoshima M Hosoda K Hanamura M Okamoto K Kobayashi H Negishi T 《Journal of photochemistry and photobiology. B, Biology》2004,73(1-2):59-66
Numerous epidemiological investigations show that sunlight is carcinogenic to humans and that the use of sunscreen may be effective in decreasing the risk of skin cancer. The biological activity of a sunscreen is evaluated by its ability to protect human skin from erythema as represented by a Sun Protection Factor (SPF). We propose that the sunscreen's protective effect against sunlight-induced genotoxicity, including mutation, should also be taken into account. In this study we examined the protective ability of sunscreens against natural sunlight and UV-induced genotoxicity in Drosophila somatic cells. We prepared three kinds of sunscreen samples, each with an SPF value of 20, 40 or 60 and compared their protective activities with commercial sunscreens. When a sunscreen of SPF 20, 40 or 60 was pasted on the plastic cover of a petri dish in which Drosophila larvae were exposed to the sun or UV lamps, genotoxicity decreased as the SPF of the sunscreen increased, relative to levels of genotoxicity observed in samples without sunscreen. However, the protective abilities of sunscreens were unexpectedly not so different from each other. To reveal the relationship between the protective activity of sunscreen and the wavelength of light with which larvae were irradiated through the sunscreen, we measured the transmittance of light through the petri dish cover on which the sunscreen was pasted. Effective protection was demonstrated by removing components of light whose wavelengths were below 315 nm. We suggest, that the measurement of anti-genotoxic activity and the determination of the wavelengths of light transmitted through the sunscreen should be an alternative method for evaluating the effectiveness of a sunscreen. 相似文献
55.
Kanako Oshiro 《Topology and its Applications》2012,159(4):1092-1105
We introduce the notion of pallets of quandles and define coloring invariants for spatial graphs which give a generalization of Fox colorings studied in Ishii and Yasuhara (1997) [4]. All pallets for dihedral quandles are obtained from the quotient sets of the universal pallets under a certain equivalence relation. We study the quotient sets and classify their elements. 相似文献
56.
Masami Fukushima Mitsuo Yamamoto Takeshi Komai Kanako Yamamoto 《Journal of Analytical and Applied Pyrolysis》2009,86(1):200-206
Pyrolysis-gas chromatography/mass spectrometry using tetramethylammonium hydroxide (TMAH-py-GC/MS) was used to characterize the humic acids (HAs) produced during the composting of conifer bark. The syringyl to guaiacyl ratios of HAs during composting were estimated from the peak area ratios for 3,4,5-trimethoxy to 3,4-dimethoxy benzene derivatives (0.11–0.50), which are characteristic of conifer species. The peak areas for nitrogen-containing and fatty acid pyrolysate compounds increased significantly during composting, indicating the degree of humification during composting. HA samples from the bark composts contained higher levels of diterpene resin acids, monoterpenes and sesquiterpenes. To investigate the species of terpenes, the HA was extracted with ethanol, and the components of the extract classified into α-HA and hymatomelanic acid (HMA) fractions, respectively. The peak areas for terpenes in the α-HA fraction were much smaller than those in the original HA, indicating that the majority of terpenes were extracted into the HMA fraction. If terpenes were to bind to HMA via unspecified interactions, no peaks would be apparent for the direct injection of HMA in ethanol into the GC/MS without pyrolysis. A comparison of the total ion chromatograms of HMA for the TMAH-py-GC/MS and GC/MS revealed that terpenes in the HA had been incorporated into polymeric structures of HMA. These results indicate that terpenes are transferred from the raw bark and incorporated into HA fractions during the composting processes. 相似文献
57.
Yuki Odanaka Takuya Kanemitsu Kanako Iwasaki Yukiko Mochizuki Michiko Miyazaki Kazuhiro Nagata Masaru Kato Takashi Itoh 《Tetrahedron》2019,75(2):209-219
A highly enantioselective construction of an all-carbon quaternary stereogenic center at the α-position of malonic diesters has been achieved by Michael addition using phase-transfer catalysis. The reaction of α-monosubstituted malonates with acrylates in the presence of N-(9-anthracenylmethyl)quininium chloride as a phase-transfer catalyst afforded the corresponding α,α-disubstituted malonic diesters in high chemical yields (up to >95% yield) with high enantioselectivities (up to 95% ee). Furthermore, the product was amenable to chemoselective transformation and could be successfully converted to the corresponding α,α-disubstituted amino acid derivatives through Curtius rearrangement. 相似文献
58.
Naoyuki Kotoku Aoi Ito Shunichi Shibuya Kanako Mizuno Aki Takeshima Masaki Nogata Motomasa Kobayashi 《Tetrahedron》2017,73(10):1342-1349
An improved method for synthesizing structurally simplified analogs of cortistatin A (1), a novel anti-angiogenic steroidal alkaloid from a marine sponge, was developed. In contrast to previous methods, step- and redox-economical synthesis was achieved using a known α-bromoketone as the starting material. The structure-activity relationship study revealed that the isoquinoline portion was strictly recognized by the target molecule. Surprisingly, the introduction of the acetamide moiety on the A-ring structure dramatically enhanced the selective antiproliferative activity against endothelial cells. This new method can be easily applied to gram-scale synthesis and enabled us to prepare various analogs, which were focused on the participation of the side chain and A-ring structure. 相似文献
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60.
The synthesis of miraziridine A, a pentapeptide derivative isolated from marine sponge, and its truncated analogs has been achieved. To construct the backbone of miraziridine A, a side-chain-unprotected vinylogous arginine was condensed with an aziridine-containing fragment prepared by a conventional solid-phase procedure. An analog lacking the vinylogous arginine site showed comparable inhibitory activity with miraziridine A, whereas an analog lacking the aziridine site showed remarkably weak inhibitory activity for cathepsin B. 相似文献