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排序方式: 共有195条查询结果,搜索用时 15 毫秒
91.
Hiroyuki Shinchi Dr. Masahiro Wakao Sho Nakagawa Eiko Mochizuki Prof. Susumu Kuwabata Prof. Yasuo Suda 《化学:亚洲杂志》2012,7(11):2678-2682
Sugar chains are important molecules in cellular recognition and signaling, and quantum dots (QDs) are a very powerful tool for in vitro and in vivo imaging. Herein, we report the preparation of stable sugar‐chain‐immobilized fluorescent nanoparticles (SFNPs) and their application to the analysis of sugar‐chain–protein interactions and cellular imaging. SFNPs were easily prepared by mixing CdTe/CdS core/shell QDs with our previously developed sugar‐chain–ligand conjugates. The obtained SFNPs were very stable and could be stored for several months. In the binding analysis, β‐galactose‐ and α‐glucose‐immobilized SFNPs were specifically interacted with Ricinus communis agglutinin I and concanavalin A, respectively, and made into aggregates. The binding interaction was detected visually, fluorescently, or both. In the experiment for cellular imaging, it was found that SFNPs were predominantly taken up by human hepatocyto carcinoma cells (HepG2), suggesting the possible usage of our designed SFNPs for various biochemical analyses of sugar chains. 相似文献
92.
Hiroshi Isoda 《Journal of Physics and Chemistry of Solids》2010,71(6):892-898
The ac conductivities along the c-axis of the lutetium nitrate crystal were measured successively in the frequency range from 0.5 to 105 Hz at temperatures from 290 to 210 K. The metastable behaviors of the conductivity were found in the temperature region above 200 K. The fluctuation was given by the successive measurements of the time series of the ac conductivities and represented by non-Gaussian probability distribution function. The effect of the metastable singularity on Raman scattering spectra was observed in the metastable temperature region. 相似文献
93.
A new cascade reaction including formal [5?+?2] cycloaddition was developed. Treatment of homocinnamyl alcohol and Co2(CO)6-complexed arylpropynal with BF3·OEt2 resulted in the generation of hydrobenzocycloheptafuran having an alkyne-Co2(CO)6 complex. The reaction consists of 5-membered ring selective Prins cyclization and subsequent Friedel-Crafts cyclization. The cascade reaction was applied to a further multi-step cascade cyclization, which resulted in the formation of more complex polycyclic hydrofurans. 相似文献
94.
Keisuke Fukumura Yuki Narimatsu Shogo Moriwaki Eiko Iwakoshi-Ukena Megumi Furumitsu Kazuyoshi Ukena 《Molecules (Basel, Switzerland)》2021,26(19)
We previously identified a novel small hypothalamic protein, neurosecretory protein GL (NPGL), which induces feeding behavior and fat accumulation in rodents depending on their diet. In the present study, we explored the effects of NPGL on feeding behavior and energy metabolism in mice placed on a long-term high-fat diet with 60% calories from fat (HFD 60). Overexpression of the NPGL precursor gene (Npgl) over 18 weeks increased food intake and weight. The weekly weight gain of Npgl-overexpressing mice was higher than that of controls until 7 weeks from induction of overexpression, after which it ceased to be so. Oral glucose tolerance tests showed that Npgl overexpression maintained glucose tolerance and increased blood insulin levels, and intraperitoneal insulin tolerance tests showed that it maintained insulin sensitivity. At the experimental endpoint, Npgl overexpression was associated with increased mass of the perirenal white adipose tissue (WAT) and decreased mass of the epididymal WAT (eWAT), resulting in little effect on the total WAT mass. These results suggest that under long-term HFD 60 feeding, Npgl overexpression may play a role in avoiding metabolic disturbance both by accelerating energy storage and by suppressing excess fat accumulation in certain tissues, such as the eWAT. 相似文献
95.
Nakai T Matsuo K Kato C Takehara Y Isoda H Moriya T Okada T Sakahara H 《Magnetic resonance imaging》2000,18(10):907-1219
The blood oxygen level dependency (BOLD) contrast is a useful tool for functional neuroimaging based on the hemodynamic response to neuronal activation. We observed different hemodynamic responses in the BOLD signal between the primary sensorimotor area (SM1) and the supplementary motor area (SMA) in the sequential finger movement task. In the SMA, a stronger initial overshoot and a post-stimulus overshoot were observed. It was hypothesized from the time course analysis that the stronger initial overshoot reflected the activation of the SMA for motor control programming in the initial phase. Although the post-stimulus overshoot may be partially explained by cerebral blood flow (CBF) cerebral blood volume (CBV) uncoupling, its mechanism remained unknown. In the SM1, only the initial overshoot was observed and the level of BOLD signal was almost constant after the initial overshoot during the task period. These observations suggested that the BOLD signal is characterized by both CBF-CBV uncoupling and the neuronal activation characteristics in each region. 相似文献
96.
Seiji Isoda Akiyoshi Kawaguchi Ken-Ichi Katayama 《Journal of Polymer Science.Polymer Physics》1984,22(4):669-679
The crystal structure of poly(p-xylylene), as polymerized, is the α form. This transforms irreversibly to the β from by annealing or drawing. To clarify the mechanism of this transition, structural changes of the α and β crystals were examined with a high-temperature stage in the electron microscope. Two high-temperature phases, β1 and β2, were found and their structures were analyzed. In these structures lattice distortions due to rotational and translational motions of chains are in troduced, especially in the β2 form. The α → β transition is induced through such a disordered phase. The statistical arrangement of a molecule in the β-form unit cell results from freezing the disorder in the high-temperature phases. 相似文献
97.
98.
Glycosides of Atractylodes japonica 总被引:4,自引:0,他引:4
Kitajima J Kamoshita A Ishikawa T Takano A Fukuda T Isoda S Ida Y 《Chemical & pharmaceutical bulletin》2003,51(2):152-157
From the water-soluble portion of the methanol extract of the fresh rhizome of Atractylodes japonica, five new sesquiterpenoid glycosides, including a compound having a secoguaiane skeleton, and a new aromatic compound glycoside were isolated together with ten known compounds. Their structures were clarified by spectral investigation. 相似文献
99.
Itoh T Matsuno M Kamiya E Hirai K Tomioka H 《Journal of the American Chemical Society》2005,127(19):7078-7093
To realize fairly stable high-spin polycarbenes by utilizing heterospin systems comprising 2p spins of organic radicals and 3d spins of magnetic metal ions, we prepared dianthryldiazomethanes having two pyridyl groups at the 2,2'- or 2,7-positions, that is, bis[10-(4-tert-butyl-2,6-dimethylphenyl)-2-(4-pyridyl)-9-anthryl]diazomethane (2,2'-DPy-1-N(2)) and [10-(4-tert-butyl-2,6-dimethylphenyl)-9-anthryl][(10-(4-tert-butyl-2,6-dimethylphenyl)-2,7-di(4-pyridyl)-9-anthryl]diazomethane (2,7-DPy-1-N(2)). The triplet carbene DPy-(3)1 generated by photolysis of DPy-1-N(2) was characterized by ESR and UV-vis spectroscopy in a matrix at low temperature as well as by time-resolved UV-vis in solution at room temperature. The results showed that the triplet carbene DPy-(3)1 was destabilized to some extent as opposed to the parent triplet carbene before pyridination, but it was still fairly persistent, having a half-life of more than 30 min in solution at room temperature. Photoproducts from the complex between DPy-1-N(2) and Cu(hfac)(2) were characterized in a similar manner, and the results suggested that the generated carbene centers interacted magnetically with the Cu(II) ion to form a high-spin species with significant thermal stability. The fact that no significant signals due to the isolated triplet carbene DPy-(3)1 were observed suggested that the pyridine moiety binds with Cu(hfac)(2) in a nearly quantitative manner under these cryogenic conditions. Magnetic measurements of the photoproduct using a superconducting quantum interference device (SQUID) magneto/susceptometer were performed to determine the spin state of the complex. The temperature dependence of the molar paramagnetic susceptibility indicated the presence of ferromagnetic interaction. The field dependences of magnetization for the complexes, expressed using M versus H/T plots, were analyzed in terms of the two-component Brillouin function to be S = 3.18 (F = 0.66) and S = 0.02 (F = 0.23) for the 1:1 complex of 2,7-DPy-1 and Cu(hfac)(2) and S = 2.70 (F = 0.33) and S = 0.49 (F = 0.11) for the 1:1 complex of 2,2'-DPy-1 and Cu(hfac)(2). 相似文献
100.
Five triterpene glycosides from Oxytropis myriophylla 总被引:1,自引:0,他引:1
Okawa M Yamaguchi R Delger H Tsuchihashi R Nohara T Kinjo J Isoda S Ida Y 《Chemical & pharmaceutical bulletin》2002,50(8):1097-1099
Four new triterpene glycosides: one cycloartane-type glycoside and three azukisapogenol glycosides were isolated together with one known oleanene bisdesmoside from the Mongolian natural medicine, Oxytropis myriophylla. 相似文献