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71.
Fujita S Ninomiya M Efdi M Ohguchi K Nozawa Y Koketsu M 《Natural product research》2010,24(17):1630-1636
Six chemical constituents were isolated from Enicosanthum cupulare (King) Airy-Shaw. The structures of the isolated compounds were determined using 1D, 2D-NMR and were found to be identical to those previously reported for these compounds. Three aporphine alkaloids, O-methylmoschatoline, liriodenine and oxostephanine were isolated from this plant for the first time. In addition, we examined the effects of these compounds on melanogenesis in murine B16 melanoma cells; O-methylmoschatoline increased melanin content in these cells. 相似文献
72.
Choi J Tachikawa T Kim Y Fujitsuka M Ihee H Majima T 《Chemical communications (Cambridge, England)》2010,46(48):9155-9157
The study of the structural reorganization and photophysical properties of Zn-Cytc using the single-molecule and ensemble-averaged spectroscopy shows that the photoblinking behaviors of single-Zn-Cytc depend on the folded and unfolded structures, whereas the fluorescence dynamics of Zn-Cytc observed in the bulk phase are hardly affected by the conformational change of a protein. 相似文献
73.
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75.
The purpose of this article is to study an existence of p-bases and mainly to give some regularity criteria for semilocal rings essentially of finite type over fields. 相似文献
76.
Modern modeling approaches for circuit analysis lead to differential-algebraic equations (DAEs). The index of a DAE is a measure of the degree of numerical difficulty. In general, the higher the index is, the more difficult it is to solve the DAE. The index of the DAE arising from the modified nodal analysis (MNA) is determined uniquely by the structure of the circuit. Instead, we consider a broader class of analysis method called the hybrid analysis. For linear time-invariant electric circuits, we devise a combinatorial algorithm for finding an optimal hybrid analysis in which the index of the DAE to be solved attains the minimum. The optimal hybrid analysis often results in a DAE with lower index than MNA. 相似文献
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78.
Keisuke Yoshiki Hiroki Azuma Kazuhiko Yoshioka Mamoru Hashimoto Tsutomu Araki 《Optical Review》2005,12(5):415-419
We have investigated the fluorescence lifetime properties of 8 calcium ion probes, calcium-green-1, calcium green-2, calcium
green-5N, calcium orange, oregon green 488 BAPTA-6F, fluo-3, fluo-4, and fluo-5N. We found that the decay time of calcium
green-5N varied more sensitively with calcium concentration than calcium green-1 which was known to be a highly sensitive
probe. We have also found that the center of observable range of calcium concentration by fluorescence lifetime measurement
is lower than that by fluorescence intensity measurement. 相似文献
79.
Danuta Frackowiak Mamoru Minuro Iwao Yamazaki† Naoto Tamai† Yoshihiko Fujita 《Photochemistry and photobiology》1989,50(4):563-570
–Time-resolved fluorescence spectra in the ps time range were measured on phycobilisome (PBS) embedded in poly(vinyl alcohol) films. The cyanobacterium Tolypothrix tenuis was used as a source of PBS because the pigment composition and the structure of the PBS are well defined. Isotropic PBS in the unstretched film and PBS uniaxially oriented in the stretched film were investigated. Diameters of PBS hemidiscs were oriented parallel to the film-stretching direction. The time-resolved fluorescence spectra of the unstretched sample and of the two polarized components in the stretched samples showed several differences in the rise and decay. The delay time, estimated from the time span between the maximum laser pulse and maximal intensity of the phycocyanin and allophycocyanin fluorescence, was much longer than that reported in the aqueous media. This suggests occurrence of a higher thermal deactivation of PBS in polymer film than in aqueous media. The excitation energy transfer from excited phycocrythrin to allophycocyanin was more efficient in the unstretched than in the stretched samples, and it was greater in the parallel polarized component of the stretched sample than in the perpendicular component. The present results are in agreement with a previous suggestion which states that there are two independent pathways of excitation energy transfer in PBS and that there is more than one final emitter of fluorescence. The molecules taking part in various pathways of energy transfer differ in their orientation within PBS. 相似文献
80.