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排序方式: 共有1217条查询结果,搜索用时 46 毫秒
101.
Kyoko Kofuji Yuzhou Huang Kazufumi Tsubaki Fumihiko Kokido Kazunori Nishikawa Takashi Isobe Yoshifumi Murata 《Reactive and Functional Polymers》2010,70(10):784-789
A transparent wound dressing sheet was obtained by forming a complex between β-glucan and chitosan (CS). These materials were chosen for their biocompatible, bioabsorbable, and biodegradable properties, and they were expected to promote the therapeutic efficacy of the dressing by increasing the wound healing response. The therapeutic efficacy of the β-glucan–CS complex sheet as a wound dressing was evaluated in wounds created on the dorsal surfaces of mice. β-glucan–CS complex sheets demonstrated therapeutic efficacies comparable or superior to that of Beschitin®W, a commercial wound dressing made from CS. Additionally, the β-glucan–CS complex sheet did not dissolve during the application period, did not adhere to wounds, and was easy to remove. Cumulatively, these results indicate that β-glucan–CS complex sheets are a promising new wound dressing product. 相似文献
102.
C. Gaire Y. Ou H. Arao M. Egami A. Nakashima R. C. Picu G.-C. Wang T.-M. Lu 《Journal of Porous Materials》2010,17(1):11-18
Mechanical properties of porous methyl silsesquioxane samples with dielectric constant 2.4 and 2.0 and a recently developed
nanoclustering silica film samples with dielectric constants 2.3 and 2.0 were evaluated using an atomic force microscope based
nanoindentation. It was found that the Young’s modulus and the hardness decrease while the fracture toughness increases with
a decrease in the dielectric constant in the same type of material. Moreover, the Young’s modulus and the hardness of the
nanoclustering silica films were observed to be at least twice and fracture toughness values ~1.3–1.5 higher than those for
methyl silsesquioxane films with similar dielectric constants. The high resolution topographic imaging capability of atomic
force microscope was shown to be particularly useful in the measurement of cracks generated by the ultra-low indentation loads,
and the evaluation of the fracture toughness of the nanoscale volumes of materials. 相似文献
103.
Takao Morimura Masayuki Hasaka Kunikazu Shimoda Hiromichi Nakashima 《Journal of Electronic Materials》2010,39(9):2149-2153
The thermoelectric half-Heusler compounds Ti
x
NiSn0.998Sb0.002 (x = 1.0 to 1.2) and Ti
y
Zr0.25Hf0.25NiSn0.998Sb0.002 (y = 0.5 to 0.65) with nonstoichiometric nominal compositions were prepared by spin-casting and subsequent annealing at 1073 K
for 24 h. The dimensionless figure of merit ZT at room temperature was maximized at x = 1.1 and y = 0.6 in Ti-rich compounds through an increase in absolute Seebeck coefficients despite a decrease in electrical conductivities.
ZT reached 0.07 at x = 1.1 and 0.14 at y = 0.6. In powder x-ray diffraction analysis, minor phases of β-Sn, TiNi, Ti2Sn, and Ti5Sn3 were observed in addition to a major phase of half-Heusler. The quantity of the minor phases was minimized at x = 1.1 and y = 0.55, where the absolute Seebeck coefficients are maximized. In transmission electron microscopic (TEM) analysis of Ti0.55Zr0.25Hf0.25NiSn0.998Sb0.002, crystal grains of the half-Heusler phase, from several hundred nanometers to several micrometers in size, were observed.
TEM energy-dispersive spectroscopy measurements indicated that fluctuations of Ti, Zr, and Hf compositions within the Ti-site
in the half-Heusler phase may occur. Thermoelectric properties were improved at x = 1.1 and y = 0.6 rather than at the stoichiometric compositions of x = 1.0 and y = 0.5 due to minimization of the precipitate quantities. 相似文献
104.
Yuki Nakashima You Zhou Keisuke Tanabe Souhei Arima Kiyoshi Hirao Tatsuki Ohji Norimitsu Murayama Manabu Fukushima 《Journal of the American Ceramic Society》2023,106(2):1139-1148
Silicon nitride (Si3N4) was prepared from silicon by a sintered reaction-bonded silicon nitride method using yttria and magnesia as sintering additives. Post-sintering (PS) of nitrided compacts was carried out at 1850°C under a nitrogen pressure of 1 MPa. Effect of PS time on microstructure and dielectric breakdown strength (DBS) of the prepared Si3N4 ceramics was evaluated. The DBS was measured using specimens with four different thicknesses (0.30, 0.20, 0.10, and 0.05 mm) in order to examine the thickness dependence. The porosity of the sintered Si3N4 decreased by prolonging the PS time, and the full density could be achieved at the PS time of over 6 h. After full densification, rod-like β-Si3N4 grains grew up, and their maximum grain size increased from 45.1 to 154.7 μm by prolonging the PS time from 6 to 48 h. The DBS of the thick Si3N4 substrates (0.30 mm) showed little variation from 35.4 to 47.0 kV/mm, regardless of the PS time. On the other hand, that of the thin ones (0.05 mm) dramatically decreased from 99.5 to 9.8 kV/mm with increased the PS time from 6 to 48 h. Because the DBS sharply decreased at the thin substrate sintered for longer time in which some large-elongated grains might span the substrate thickness-wise throughout, it was inferred that the interface between β-Si3N4 grains and grain boundary phase/intergranular glassy films might be a path of the dielectric breakdown. 相似文献
105.
N Nakashima DW Rose S Xiao K Egawa SS Martin T Haruta AR Saltiel JM Olefsky 《Canadian Metallurgical Quarterly》1999,274(5):3001-3008
Crk is a member of a family of adapter proteins predominantly composed of Src homology 2 and 3 domains, whose role in signaling pathways is presently unclear. Using an in situ electroporation system which permits the introduction of glutathione S-transferase (GST) fusion proteins into cells, we found that c-CrkII bound to p130(cas), but not to paxillin in serum-starved rat-1 fibroblasts overexpressing the human insulin receptor (HIRc cells) in vivo. 17 nM insulin stimulation dissociated the binding of c-CrkII to p130(cas), whereas 13 nM insulin-like growth factor-I, 16 nM epidermal growth factor (EGF), and 10% serum each showed little or no effect. We found that stress fiber formation is consistent with a change in the p130(cas).c-CrkII interactions before and after growth factor stimulation. Microinjection of either GST-Crk-SH2 or -Crk-(N)SH3 domains, or anti-Crk antibody each inhibited stress fiber formation before and after insulin-like growth factor-I, EGF, and serum stimulation. Insulin stimulation by itself caused stress fiber breakdown and there was no additive effect of microinjection. Microinjection of anti-p130(cas) antibody also blocked stress fiber formation in quiescent cells. Microinjection of the Crk-inhibitory reagents also inhibited DNA synthesis after insulin-like growth factor-I, EGF, and serum stimulation, but not after insulin. These data suggest that the complex containing p130(cas).c-CrkII may play a crucial role in actin cytoskeleton organization and in anchorage-dependent DNA synthesis. 相似文献
106.
Takayuki Ban Naoya Nakashima Tomohiko Nakatani Yutaka Ohya 《Journal of the American Ceramic Society》2009,92(6):1230-1235
We hydrothermally synthesized anatase films on Ti substrates from transparent aqueous solutions of layered titanate colloids. The morphology and wetting properties of the films were examined. The films consisted of columnar aggregates grown on the Ti substrates, which resulted in high orientation. Randomly oriented films were obtained when alumina was used as a substrate, whereas the sol–gel precoating of a titanium oxide (TiO2 ) layer on alumina substrates resulted in similar orientation as that of the films on Ti substrates. Thus, the presence of TiO2 on the substrate surface plays an important role in the orientation of columnar aggregates. The columnar aggregates were similar in microstructure to the arms of a type of six-pointed star-like anatase aggregate synthesized hydrothermally from the same reaction solutions. They were composed of twins of tapered anatase nanocrystals, which provided a rough film surface. The film surface was highly hydrophilic and oleophilic due to the nanoscale roughness even when the film was not irradiated with UV light. 相似文献
107.
Hideaki Fujita Kazunori ShimizuYuki Morioka Eiji Nagamori 《Journal of Bioscience and Bioengineering》2010,110(3):359-362
We have studied the effect of enhanced oxygen delivery by perfluorocarbons on the differentiation of C2C12 cells. The extent of differentiation was assessed by means of phase contrast/fluorescence microscopy, active tension measurement and the glucose consumption/lactate production rates. We found that enhanced oxygen delivery is suitable for full differentiation of C2C12 cells. 相似文献
108.
Abstract Data on the distribution of uranium(IV,VI), plutonium(III) and nitric acid between 30 vol.% TBP in dodecane and aqueous nitrate solutions also containing hydrazine nitrate were mathematically described by empirical equations. This made it possible to present distribution ratios of the extracted components as functions of concentrations and temperature at a single variable being varied and other variables being kept constant. Salting-out and self-salting-out action of the electrolytes present in the system as well as mutual replacement of the extracted components from the organic phase are shown. 相似文献
109.
W. Shin T. Nakashima M. Nishibori T. Itoh N. Izu I. Matsubara Y. Nakagawa A. Yamamoto H. Obara 《Journal of Electronic Materials》2011,40(5):817-822
The performance of a microcombustor thermoelectric generator device based on a thermopile using p-type Bi0.3Sb1.7Te3 (BST) and n-type Pt films has been investigated. The BST films were prepared by two different methods—pulsed laser deposition (PLD) and
sputter deposition—on Si3N4/SiO2 multilayers on Si substrate. The ceramic catalyst combustor was patterned on the thermopile end on a thin membrane fabricated
by back-side bulk etching of the silicon substrate. At 138°C the thermoelectric power factors of the PLD and sputter-deposited
films were 3.6 × 10−3 W/mK2 and 0.22 × 10−3 W/mK2, respectively. The power from the generator with the sputter-deposited film was 0.343 μW, which was superior to that of the device with the PLD film, which provided 0.1 μW, for combustion of a 200 sccm flow of 3 v/v% hydrogen in air. 相似文献
110.
S. Kouda K. Kimura H. Nakamura H. Ochiishi T. Nakashima S. Morinobu 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1999,420(3):380
For the study of parity mixing in the compound states, a method to measure the longitudinal analyzing power Az of the isobaric analog resonance (IAR) as a function of energy in the proton elastic scattering is discussed. A thick target is used and energy loss of the protons in the target is utilized to measure the energy dependence. The energy resolution is presented and the sources of the systematic errors in Az are discussed together with the way of their elimination. The method has been shown to be quite efficient for deriving both the transverse and the longitudinal analyzing powers. The measurement of Az for the s-wave IAR at Ecm=5.86 MeV in 90Zr(p,p) and the analysis to derive PNC matrix elements are described. 相似文献