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61.
Kiyotaka Tanaka Yuki Akiyama Kazuo Hayakawa Ken-ichi Yukihira Yutaka Yoshida 《Hyperfine Interactions》2012,208(1-3):75-78
Twenty CK chondrites collected in the Antarctica Continent were characterized by inductively-coupled plasma mass spectrometry (ICP-MS), prompt gamma ray analysis (PGA), instrumental neutron activation analysis (INAA), X-ray diffractometry (XRD) and 57Fe-M?ssbauer spectroscopy. As a result of elemental analysis, it was revealed that 18.2~26.4 mass% of iron was included in the each chondrite. M?ssbauer spectrum of LEW86258, classified as a typical CK chondrite, was found to be composed of two paramagnetic doublets and two magnetic sextets. M?ssbauer spectra were assigned to the absorption due to forsterite (Mg1.36Fe0.64SiO4) and magnetite (Fe3O4), as also confirmed by XRD. XRD study of LAP03834, reclassified from CK to R chondrite, revealed the presence of crystalline phase due to forsterite. These results indicate that LAP03834 and related chondrites, i.e., MET01149, LAP03923 and MAC02453, should be reclassified as R or LL chondrite. 相似文献
62.
Dr. Tsubasa Nakashima Haruka Fujimori Dr. Kohsuke Ohmatsu Prof. Takashi Ooi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(36):9253-9256
Intermediary radical cations, generated through single-electron oxidation of enol silyl ethers by excited Ir-based photocatalysts, can be exploited as Brønsted acids for the activation of heteroarylcyanides. This strategy enables the direct allylic C−H heteroarylation of enol silyl ethers under visible-light irradiation. 相似文献
63.
Thermal response was measured for a deeply supercooled glycerol specimen by applying calorimetric temperature scanning rate spectroscopy, cooling the specimen from liquid at a slow constant cooling rate until glass transition was observed. The effective fraction of glass as a function of temperature was determined and a new definition of glass transition temperature, TgC, as the temperature at which the effective glass fraction to be 0.5 was presented. The relation between this and the cooling rate showed the Arrhenius behavior. The effective glass fraction curves shifted linearly as a function of ln(cooling rate). When T was scaled to the Lillie Number, the glass fraction lay on a master curve, which was successfully fitted with a Kohlrausch–Williams–Watts function. The Kohlrausch exponent, the relaxation time as a function of temperature and the kinetic fragility index were determined. The results were compared with literature values. 相似文献
64.
Prof. Dr. Tomoaki Tanase Dr. Kanako Nakamae Yume Okawa Mami Hamada Dr. Arimasa Matsumoto Prof. Dr. Takayuki Nakajima Prof. Dr. Takuya Nakashima Prof. Dr. Tsuyoshi Kawai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(8):e202104060
A P-stereogenic linear tetraphosphine tetraoxide, (R,R)- or (S,S)-dpmppm(=O)4, was synthesized to prepare C2 dinuclear M(hfa)3 complexes (M=Eu, Tb, Y) as the first example of lanthanide(III) complexes with P-chiral multidentate phosphine oxides. The mononuclear M(hfa)3 complexes (M=Eu, Y) with a P-chiral diphosphine dioxide, tpdpb(=O)2, were also prepared, and comparison of their photophysical properties for the EuIII complexes revealed that significant chiral induction from the P-chiral centers arises on the achiral M(hfa)3 units through intramolecular π-π stacking constraint in the dinuclear system. 相似文献
65.
Order - A modular semilattice is a semilattice generalization of a modular lattice. We establish a Birkhoff-type representation theorem for modular semilattices, which says that every modular... 相似文献
66.
Makoto Tsuruya Yoshimi Niwano Keisuke Nakamura Taro Kanno Takuji Nakashima Hiroshi Egusa Keiichi Sasaki 《Applied biochemistry and biotechnology》2014,174(6):2223-2235
Under the hypothesis that photo-irradiated proanthocyanidin could accelerate wound healing through reactive oxygen species (ROS) formation, we examined the effect of proanthocyanidin on 3T3-L1 mouse fibroblasts with or without photo-irradiation. As a result, irrespective of presence or absence of photo-irradiation, only 1 min exposure of the cells to proanthocyanidin resulted in accelerated proliferation of the cells in a concentration-dependent manner. Similarly to proanthocyanidin, 1 min pretreatment with catechin, caffeic acid, and chlorogenic acid accelerated the proliferative response, but gallic acid, epicatechin gallate, epigallocatechin, and epigallocatechin gallate failed. If incorporated active ingredient such as proanthocyanidin for such a short time as 1 min accelerates the proliferation response, a bioassay was conducted by utilizing antioxidant potential of proanthocyanidin. That is, intracellular oxidation of 2′,7′-dichlorodihydrofluorescin induced by H2O2 was significantly inhibited when the cells were pretreated with proanthocyanidin for 1 min, suggesting that incorporated proanthocyanidin into the cells exerted antioxidant effect. This was also supported by a liquid chromatography/mass spectrometry analysis in which incorporation of proanthocyanidin components such as catechin monomers and dimers into the cells within 1 min was confirmed. These results suggest that active polyphenolic compounds such as proanthocyanidin, catechin, caffeic acid, and chlorogenic acid incorporated into the cells in such a short time as 1 min could accelerate the proliferative response of the cells. 相似文献
67.
Understanding the quantitative analysis of the transition adsorption structures of molecules on single‐walled carbon nanotubes (SWNTs) is of importance from the point of view of both fundamental science and applications of nanotubes. Absorption spectroscopy reveals that two different equilibrium states are existent for the exchange reaction of sodium cholate (SC) and oligo‐DNA (single‐stranded 20‐mer cytosine) on SWNTs. This is derived from the transitions of the adsorption structures of different chirality‐types of SWNTs and SC/DNA at certain SC concentrations below the critical micelle concentration of SC. 相似文献
68.
Kenichiro Todoroki Hiroki Hashimoto Kazuyuki Machida Miki Itoyama Tadashi Hayama Hideyuki Yoshida Hitoshi Nohta Manabu Nakashima Masatoshi Yamaguchi 《Journal of separation science》2013,36(2):232-238
In this study, we combined a column‐switching system with a fluorous scavenging derivatization method to develop a fully automated reagent peak‐free LC fluorescence detection protocol for the analysis of highly polar carboxylic acids. In this method, highly polar carboxylic acids were derivatized with fluorescent 1‐pyrenemethylamine in the presence of 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide and 1‐hydroxy‐1H‐benzotriazole. Residual excess of the unreacted reagent was tagged with 2‐(perfluorooctyl)ethyl isocyanate and then removed selectively using a fluorous column‐switching system placed in front of an analytical reversed‐phase column. The signal of the fluorous‐tagged unreacted reagent was completely absent in the resulting chromatograms; therefore, it did not interfere with the quantification of each acid especially those eluted before 20 min. The detection limits (S/N = 3) for the examined acids were in the range from 4.0 to 22 fmol per injection. We have applied this method to comparative analysis of highly polar carboxylic acids in urine samples obtained from diabetes mellitus type‐II model mice and their control. 相似文献
69.
J. P. Mata P. R. Majhi M. Yamashita A. Khanal K. Nakashima P. Bahadur 《Journal of Dispersion Science and Technology》2013,34(9):1248-1256
The effect of sodium dodecyl sulfate (SDS) on the micellization and aggregation behavior of a poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-PPO-PEO) amphiphilic copolymer (Pluronic L64: EO13 PO30 EO13) have been investigated by various techniques like, cloud point, viscosity, isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), fluorescence spectroscopy, room temperature phosphorescence (RTP), and small angle neutron scattering (SANS). Addition of SDS in L64 solutions shows mark alteration of different properties. We observed synergistic interaction between SDS and Pluronic L64. The changes in the critical micelle concentration (CMC), critical micelle temperature (CMT), cloud point (CP), micelle size, and shape has been correlated and reported in terms of structure dynamics and mechanics. The ITC titrations have been used to explore the different stages of binding and interactions of SDS with L64. The enthalpies of aggregation for copolymer-SDS aggregates binding, organizational change of bound aggregates, and the threshold concentrations of SDS in the presence of copolymer were estimated directly from ITC titration curves. The effect of temperature on enthalpy values has been reported in terms of different aggregation state. Fluorescence and RTP for L64 were used to investigate the change in micellar environment on the addition of SDS at different temperature. Appearance and shifting of SANS peaks have been used to monitor the size and inter micellar interaction on addition of SDS in L64 solution. Cloud point and viscosity elaborate the penetration of SDS molecule in L64 micelle and hence changing the micellar architect. 相似文献
70.
Dr. Bishnu Prasad Bastakoti Prof. Kevin C.‐W. Wu Dr. Masamichi Inoue Prof. Shin‐ichi Yusa Prof. Kenichi Nakashima Prof. Yusuke Yamauchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(15):4812-4817
We have developed core‐shell‐corona‐type polymeric micelles that can integrate multiple functions in one system, including the capability of accommodating hydrophobic dyes into core and hydrophilic drug into the shell, as well as pH‐triggered drug‐release. The neutral and hydrophilic corona sterically stabilizes the multifunctional polymeric micelles in aqueous solution. The mineralization of calcium phosphate (CaP) on the PAA domain not only enhances the diagnostic efficacy of organic dyes, but also works as a diffusion barrier for the controlled release. 相似文献