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31.
Yoshiaki Hattori Shinobu Mukasa Hiromichi Toyota Shinfuku Nomura 《Current Applied Physics》2013,13(6):1050-1054
The electrical breakdown of microwave plasma in water was investigated between 1 and 30 kPa. The dependency of the ignition power for generating plasma on the size of coaxial electrode was measured. The ignition power decreases with a decrease of the diameter of the inner electrode. The behavior of microwave plasma in water was observed using a high-speed camera. The plasma ignites in a bubble generated by microwave heating. The model for calculating the electric field was created on the basis of the captured images of the bubble just before plasma ignition. The method presented can be used to visualize the electrical field distribution in the bubble. The electric field breakdown was calculated using the measured ignition power. The electric field breakdown of plasma in water is of the same order as gas phase plasma. 相似文献
32.
Y.J. Uemura R.S. Hayano J. Imazato N. Nishida T. Yamazaki 《Solid State Communications》1979,31(10):731-734
The zero-field spin relaxation function of μ+ observed in ZrH2 has revealed that the second moment of the nuclear dipolar broadening is five times larger than the high-field value. This experiment clearly demonstrates the recovery of the non-secular part of dipolar interaction between unlike spins. A general expression of zero-field relaxation function is presented to account for a slow modulation of random fields on μ+ found at room temperature. 相似文献
33.
The structure and O2-reactivity of a series of copper(I) complexes supported by the pyridylalkylamine ligands are summarized, and the ligand effects such as the chelate ring size effect (five- vs. six-membered ring), the denticity effect (tetradentate vs. tridentate vs. didentate), the steric effect of 6-methylpyridine and the steric and/or electronic effects of N-alkyl substituents are discussed in detail. 相似文献
34.
Yamazoe H Uemura T Tanabe T 《Langmuir : the ACS journal of surfaces and colloids》2008,24(16):8402-8404
Fabrication of micropatterned surfaces to organize and control cell adhesion and proliferation is an indispensable technique for cell-based technologies. Although several successful strategies for creating cellular micropatterns on substrates have been demonstrated, a complex multistep process and requirements for special and expensive equipment or materials limit their prevalence as a general experimental tool. To circumvent these problems, we describe here a novel facile fabrication method for a micropatterned surface for cell patterning by utilizing the UV-induced conversion of the cell adhesive property of albumin, which is the most abundant protein in blood plasma. An albumin-coated surface was prepared by cross-linking albumin with ethylene glycol diglycidyl ether and subsequent casting of the cross-linked albumin solution on the cell culture dish. While cells did not attach to the albumin surface prepared in this way, UV exposure renders the surface cell-adhesive. Thus, surface micropatterning was achieved simply by exposing the albumin-coated surface to UV light through a mask with the desired pattern. Mouse fibroblast L929 cells were inoculated on the patterned albumin substrates, and cells attached and spread in a highly selective manner according to the UV-irradiated pattern. Although detailed investigation of the molecular-level mechanism concerning the change in cell adhesiveness of the albumin-coated surface is required, the present results would give a novel facile method for the fabrication of cell micropatterned surfaces. 相似文献
35.
Hiroyoshi Takamura Yuichiro Kadonaga Chunguang Han Daisuke Uemura 《Tetrahedron》2009,65(36):7449-7725
Cross-metathesis of methyl ester which was prepared from symbiodinolide with ethylene was performed to give the C33-C42 degraded fragment. This fragment was estimated to be (36S,40S)-diol by the modified Mosher method. Stereoselective synthesis of the (36S,40S)-diol and its diastereomer (36R,40S)-diol was achieved from l-aspartic acid. Synthetic bis-(S)- and (R)-MTPA esters which were derivatized from the (36S,40S)-diol exhibited spectroscopic data identical with those of bis-(S)- and (R)-MTPA esters derived from the degraded product. Thus, the absolute stereochemistry of the C33-C42 fragment was elucidated to be (36S,40S). 相似文献
36.
Prof. Dr. Takashi Uemura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(6):1482-1489
Controlled organization of polymer chains into ordered structures is highly important to tune or enhance the properties of the polymeric materials. A supramolecular approach using host–guest chemistry has allowed rational design of chain assemblies with many functional properties. Nanoporous materials with ordered channel structures are particularly useful for attaining precise assemblies of polymer chains through nanoconfinement. 相似文献
37.
The complete structure of palytoxin (1) was elucidated by us in 1982.1 Our continuous interests in palytoxin led us to examine minor constituents of Okinawan Palythoa tuberculosa. In this paper, we describe successful isolation and structural elucidation of four minor toxins, which were named homopalytoxin (2), bishomopalytoxin (3), neopalytoxin (4) and deoxypalytoxin (5). 相似文献
38.
Oxidation of alcohols to corresponding carbonyl compounds by coenzyme PQQ-trimethyl ester was performed in the presence of aluminum t-butoxide or aluminum chloride under anaerobic conditions. Reduced PQQTME (PQQTMEH2) was obtained by acidification of an aluminum complex of reduced PQQTME which was isolated in the reaction. 相似文献
39.
Takashi Uemura Nobuyuki Okuda Hiroya Kirmura Yasuko Okuda Yoshinobu Ueba Tuguru Shirakawa 《先进技术聚合物》1997,8(7):437-442
Electroluminescent(EL) devices have been fabricated using four different polymers with different glass transition temperatures (Tg) dispersed with N,N′-bis-(3-methylphenyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (TPD) as a hole transport layer and tris(8-hydroxyquinoline) aluminum (Alq3) as an emitting layer. It was found that the higher the Tg of the polymer, the longer the lifetime of the device. From observations of TPD-doped polymer films with optical microscope and atomic force microscope, dispersing TPD in the polymers was found to suppress the crystallization that causes the roughness of the film surface. It was also observed that the higher the Tg of the host polymers, the more difficult TPD crystallization was. The property of the EL device with polyethersulfone (PES) dispersed with TPD was also investigated. The lifetime of EL device with the TPD doped PES film was improved more than five times at a current density below 10 mA/cm2 compared with the device with a conventional TPD hole transport layer. © 1997 John Wiley & Sons, Ltd. 相似文献
40.
Ono K Yoshida A Saito N Fujishima T Honzawa S Suhara Y Kishimoto S Sugiura T Waku K Takayama H Kittaka A 《The Journal of organic chemistry》2003,68(19):7407-7415
Six novel 2-substituted analogues of 1alpha,25-dihydroxy-19-norvitamin D(3), 6a,b-8a,b, were efficiently synthesized utilizing (-)-quinic acid as the A-ring precursor. The C2-modified A-rings were prepared as 4-alkylated (3R,5R)-3,5-dihydroxycyclohexanones 12-15 from (-)-quinic acid based on radical allylation at the C4 position of methyl (-)-quinicate. The new type of the CD-ring coupling partner 23 was synthesized from 25-hydroxy Grundmann's ketone 19 to apply to the modified Julia olefination to construct a diene unit between the A-ring and the CD-ring. The coupling yields, including a deprotection step, were 47-62%. After the separation of the diastereomers based on C2 stereochemistry, the structure (2alpha or 2beta) was determined by (1)H NMR experiments and compared to DeLuca's 2-methyl- and 2-ethyl-1alpha,25-dihydroxy-19-norvitamin D(3). Thus, the synthesized 2alpha-(3-hydroxypropyl)-1alpha,25-dihydroxy-19-norvitamin D(3) (8a) showed almost the same potency in binding to the bovine thymus vitamin D receptor (VDR) as the natural hormone 1, while its beta-isomer 8b had only a 3% affinity. Both 2alpha-allyl- and 2alpha-propyl-1alpha,25-dihydroxy-19-norvitamin D(3) (6a and 7a) and their 2beta-analogues (6b and 7b) possessed a weak affinity for the VDR. The strong VDR ligand 8a was ca. 36-fold more potent in induction of HL-60 cell differentiation than 1, and interestingly, even the weaker ligand 8b showed a 6.7-fold higher potency in the cell differentiation activity than that of 1. 相似文献