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排序方式: 共有355条查询结果,搜索用时 15 毫秒
81.
Varma HK Yokogawa Y Espinosa FF Kawamoto Y Nishizawa K Nagata F Kameyama T 《Journal of materials science. Materials in medicine》1999,10(7):395-400
Biomimetic growth of calcium phosphate compound on cotton sheets treated with tetraethoxy silane and soaked in simulated body fluid solution was studied using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), micro-Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD). Micro-FTIR and EDAX results show that silicon was coupled to the cotton fiber when cotton was treated with tetra-ethoxy silane (TEOS) at 125°C for 1 h. Calcium phosphate nucleation started to occur on the surface of TEOS-treated cotton fibers upon immersion in 1.5×SBF (simulated body fluid solution) within 3 days and after 20 days, all the fiber surfaces were found covered with a thick and porous coating of calcium phosphate. The Ca and P determined by inductively coupled plasma spectroscopy (ICP) analysis revealed that the Ca/P ratio as well as the amount of calcium phosphate coating depends on the soaking time in SBF solution. © 1999 Kluwer Academic Publishers 相似文献
82.
The counting efficiency and detection limit of an in vivo thyroid 131I monitoring system using an imaging plate (IP) were estimated using an anthropomorphic thyroid neck phantom. The counting efficiency of the IP system was approximately constant for thyroid volumes between 11.7 and 20 ml and neck diameters between 10 and 14 cm. The detection limits were distributed from 288 to 451 Bq depending on the combination of neck diameter, thyroid volume and tissue thickness. The IP monitoring system gives a reliable counting efficiency notwithstanding the variation of thyroid volume and neck diameter. The IP system is a new option for thyroid 131I monitoring. 相似文献
83.
Counter-selection is a useful gene manipulation technique for repeated gene disruptions, gene shufflings and gene replacements in yeasts. We developed a novel counter-selection system using a galactose-inducible growth inhibitory sequence (Kawahata et al.1999. Yeast 15: 1-10). This counter-selection marker, named GAL10p-GIN11, has several advantages over previous counter-selection markers, i.e. use of an inexpensive galactose medium for counter-selection, combined use with any transformation markers for gene introduction, and no requirement of specific mutations in the host strains. The GIN11 sequence, which is a part of an X-element of the subtelomeric regions, contained a conserved autonomously replicating sequence, causing the possibility of inefficient chromosomal integration. We isolated GIN11 mutants that lost the replication activity but retained the growth-inhibitory effect when overexpressed. A mutant GIN11M86 sequence was selected and fused to the CUP1 promoter for the counter-selection on a copper-containing medium. The GALp-GIN11M86 and the CUPp-GIN11M86 were used for constructing sets of integrating plasmids containing auxotrophic markers involving HIS3, TRP1, LEU2, URA3 or ADE2, or a drug-resistant marker PGKp-YAP1. In addition, a set of gene disruption cassettes that contained each of the auxotrophic markers and the GALp-GIN11M86, which were flanked by direct repeats of a hisG sequence, were constructed. The counter-selectable integrating plasmids and the gene disruption cassettes can allow the markers to be used repeatedly for yeast gene manipulations. 相似文献
84.
The methanation reactivity of surface carbon deposited from CO2 on the oxygen-deficient magnetite was studied by the isothermal methanation reaction and the temperature programmed surface reaction (TPSR). In the methanation reaction with H2 gas, in a closed system at 150–200C, active carbon, which was not observed by the TPSR measurements, was found. About 20% out of the deposited carbon was in the form of atomic carbon and readily converted into CH4 (5 min) above 150C with H2, and about 80% at 300C. At 350C these atomic carbons were transformed into polymerized carbons, which was less reactive for methanation. 相似文献
85.
An array of porous microneedles (PMNs) made of biodegradable poly(lactic-co-glycolic acid) (PLGA) is fabricated by a combination of molding and freeze-drying methods. The optimized mixture of PLGA and 1,4-dioxane is poured into a mold of a microneedle array, followed by the freezing and sublimation of the frozen particles of 1,4-dioxane, a procedure that left an interconnecting porous structure in the PLGA with a porosity around 50%. The mechanical strength of the PMN made of PLGA (PLGA-PMN) is reinforced by modification with carboxymethylcellulose (CMC), resulting in sufficient strength enough for insertion into an excised porcine skin. The transdermal resistance is significantly decreased by the CMC-modified PLGA-PMN, which would improve the efficiency and safety of DC current-based transdermal techniques, including the electrical monitoring of the skin condition and iontophoresis for drug delivery and medical diagnosis. 相似文献
86.
Nishizawa J.-I. Suto K. Tanabe T. Saito K. Kimura T. Oyama Y. 《Photonics Technology Letters, IEEE》2007,19(3):143-145
Terahertz (THz) generation was demonstrated from GaP rod-type waveguides via difference-frequency-mixing of near-infrared light using a collinear phase-matching condition. THz output peaks were observed, and appeared at frequencies corresponding to the fundamental and high-order waveguide modes. Interestingly, the position of the fundamental mode shifted to a higher frequency for a smaller waveguide cross-section, which is attributed to the waveguide confinement of the THz wave. The conversion efficiency was enhanced in the waveguide with a cross section of 200 mumtimes160 mum as compared to that in bulk GaP crystals 相似文献
87.
NaoyukiNishizawa Y-Y.Choi Y.Miyakoshi D.Sato T.Togawa T.Nagasawa Y.Ito MWatanabe M.Sato M-RChoi 《食品科学》2005,26(5):220-224
We examined the effects of dietary Japanese millet protein (JMP) and Korean foxtail millet protein (KFMP) on lipid metabolism and type 2 diabetes in rats and mice. When type 2 diabetic rats were fed with JMP for 20 days, plasma glucose levels lowered, whereas those of HDL-cholesterol and adiponectin rose significantly compared to the control group. Then when type 2 diabetic mice were fed with KFMPfor 20 days, 相似文献
88.
Kazumi Kato Desheng Fu Kiyotaka Tanaka Kazuyuki Suzuki Tatsuo Kimura Kaori Nishizawa Takeshi Miki 《International Journal of Applied Ceramic Technology》2005,2(1):64-72
We used a Ca–Bi–Ti complex alkoxide, in which metal–oxygen bonding was confirmed by spectroscopic analysis, to deposit CaBi4 Ti4 O15 (CBTi144) thin films in various configurations. The phase transition of non-ferroelectric pyrochlore to ferroelectric perovskite in the complex-alkoxy-derived CBTi144 thin films was found to depend on the Pt bottom electrodes. Matching of the atomic arrangement to the Ca–Bi–Ti–O thin films was predominant rather than the strain and crystallinity of the bottom electrode. The thin films crystallized at 650°C on (111)-oriented Pt showed random orientation and ferroelectric P – V hysteresis loops. The endurance property was excellent against a number of switchings. For this reason, CBTi144 thin films would be expected to be excellent for application to ferroelectric random access memories (FeRAM). Polar-axis-oriented CBTi144 films were fabricated on Pt foils using the complex metal alkoxide solution. The 500-nm-thick film had a columnar structure comprising well-developed grains. The a / b -axis orientation of the ferroelectric films is considered to be associated with the preferred orientation of Pt foil. The film showed improved ferro- and piezoelectric properties. The P r , E c , and d 33 values were enhanced to become twice those of CBTi144 thin films with random orientation. These polar-axis-oriented CBTi144 films are eminently useful in devices as Pb-free piezoelectric materials. 相似文献
89.
Two-dimensional cross-linked polysiloxane Langmuir-Blodgett (LB) films were prepared and applied to nitric oxide (NO)-permselective membranes in order to block other electroactive interfering species. The cross-linked siloxane LB films deposited on platinum micro-disc electrodes (10 μm in diameter) offered revealing high performances as a permselective membrane for NO sensor such as high sensitivity to NO (detection limit, 40 nM) and high selectivity (e.g., the ratio of current response for acetaminophen or uric acid on the modified electrode to that on the bare electrode, less than 10−3). Furthermore, the permselective membrane could be easily deposited irrespective of the size and shape of electrode. 相似文献
90.