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71.
Kawakubo A Matsunaga T Ishizaki H Yamada S Hayashi Y 《Microscopy research and technique》2011,74(12):1161-1165
BACKGROUND: Zinc (Zn) has a potent stimulatory effect on osteoblastic bone formation and an inhibitory effect on osteoclastic bone resorption. PURPOSE: The effect of Zn on the function of matrix vesicles (MVs) remains controversial. The purpose of this study was to investigate the effect of Zn on alkaline phosphatase (ALP) activity of osteoblasts and in the initial biological MVs‐mediated mineral deposition. STUDY DESIGN: Osteoblasts were treated with varying concentrations of Zn dissolved in culture medium. After three, five, and seven days of culture, ALP activity was assayed. For the detection of a low level of calcium concentration in MVs, X‐ray fluorescence (XRF) analyses were applied. The effect of Zn for the transformation of calcium phosphate was analyzed using a scanning electron microscope fitted with an energy dispersive X‐ray microanalysis (EDX) system. RESULTS: The ALP activity of osteoblasts in culture medium supplemented with 1 × 10?5M of Zn was significantly increased at both five and seven days. XRF data demonstrated higher levels of calcium concentration over time in the Zn‐supplemented group. EDX data showed that mineral deposits beginning on day 3 were transformed from whitlockite to calcium phosphate near hydroxyapatite, and that Zn accelerated this transformation. CONCLUSIONS: The proper concentration of Zn increased the ALP activity of osteoblasts after five and seven days of incubation. The present XRF and EDX data suggest that the increase of mineral deposition with Zn exposure for one to five days might be mediated by the activation of ALP and calcium‐binding proteins. Microsc. Res. Tech., 2011. © 2011 Wiley Periodicals, Inc. 相似文献
72.
On the development and characterization of a firebrand generator 总被引:1,自引:0,他引:1
Samuel L. Manzello John R. Shields Thomas G. Cleary Alexander Maranghides William E. Mell Jiann C. Yang Yoshihiko Hayashi Daisaku Nii Tsuyoshi Kurita 《Fire Safety Journal》2008
A unique experimental apparatus has been constructed in order to generate a controlled and repeatable size and mass distribution of glowing firebrands. The present study reports on a series of experiments conducted in order to characterize the performance of this firebrand generator. Firebrand generator characterization experiments were performed at the Fire Research Wind Tunnel Facility (FRWTF) at the Building Research Institute (BRI) in Tsukuba, Japan. The firebrand generator was fed with three different initial firebrand geometries, two different sized cylinders and one size of disks. Cylinders were used to simulate firebrand fluxes from vegetation, such as trees, while disks were used to simulate a firebrand flux from burning structures. Samples of these geometries were constructed from wood dowels, fed into the firebrand generator, ignited, and the glowing firebrands generated were collected using an array of water filled pans. The pans were filled with water in order to quench combustion. The collected firebrands were subsequently dried and the size and mass distribution was measured. These experiments were performed over a range of wind tunnel speeds, with no wind speed present to 9 m/s, to determine the lofting distance of the firebrands generated. Finally, the size and mass distribution produced from the firebrand generator are compared to those produced from burning trees. Results of the study are presented and discussed. 相似文献
73.
74.
A mathematical model which describes the influence of various parameters on formaldehyde concentration in the atmosphere of a room containing wood-based boards was developed. The physical meanings and measuring methods of the parameters of the model are also discussed. Based on this model, two indices for commenting the formaldehyde emission process of wood-based boards are proposed, and inequality estimation for the formaldehyde content of wood-based boards at any moment and a time estimation which shows when the room satisfies the environment quality standard are also given. 相似文献
75.
Masayuki Imose Akihiro Ohta Yoshihiko Takano Masaru Yoshinaka Ken Hirota Osamu Yamaguchi 《Journal of the American Ceramic Society》1998,81(4):1050-1052
Mullite/Y-TZP composites in the mullite-rich region, using powders of mullite prepared via the hydrazine method and a commercially available zirconia compound (ZrO2 (2Y)), have been fabricated by sintering for 3 h at 1450°C in air. The grain sizes of mullite and ZrO2 (2Y) are changed with increased ZrO2 (2Y) content; the former decreases from 0.25 µm to 0.13 µm, and the latter increases from 0.21 µm to 0.35 µm. High strength (780 MPa) and fracture toughness (5.4 MPam1/2 ) are obtained in the 50/50 (vol%) mullite/ZrO2 (2Y) composite with 99.6% of theoretical density. 相似文献
76.
Bio-inorganic approach to hydrocarbon oxidation 总被引:2,自引:0,他引:2
Oxidation reactions mimicking the biological oxidative processes are summarized. A dioxygen molecule can be activated by way of reductive activation within a coordination sphere of transition metal complexes, and the resulting electrophilic oxo species, which can also be generated by treatment with an oxo transfer reagent (so-called “shunt path”), exhibit oxidizing ability just like an oxene species. 相似文献
77.
Hiroki Takahashi Takahiro Tomita Hiroyuki Takahashi Yoshikazu Mizuguchi Yoshihiko Takano Satoshi Nakano Kazuyuki Matsubayashi Yoshiya Uwatoko 《Science and Technology of Advanced Materials》2012,13(5)
The superconducting transition temperature, Tc, in iron-based solids can be enhanced by applied pressure: Tc increases from 8 to 37 K for the 11-type FeSe when the pressure is raised from 0 to 4 GPa. High-pressure studies can elucidate the mechanism of superconductivity in such novel materials. In this paper, we present a high-pressure study of Fe(Se1−xTex) and Fe(Se1−xSx). In the case of Fe(Se1−xTex), the maximum Tc under high pressure did not exceed the Tc of FeSe, which can be attributed to the structural transition to the monoclinic phase. For Fe(Se1−xSx) (0 < x < 0.3), Tc exhibited a significant increase with pressure; however, the maximum Tc under high pressure did not exceed the Tc of FeSe. This may be due to the disorder induced by substituting S for Se, which is similar to the pressure effect on Tc for the 1111-type superconductor Ca(Fe1−xCox)AsF. The Tc of Fe(Se1−xSx) showed a complex behavior below 1 GPa, first decreasing and then increasing with increasing pressure. From high-pressure x-ray diffraction measurements, the Tc (P) curve was correlated with the local structural parameter. 相似文献
78.
Renzhong Huang Hirotaka Fukanuma Yoshihiko Uesugi Yasunori Tanaka 《Journal of Thermal Spray Technology》2013,22(2-3):183-191
The hypothesis of local thermal equilibrium (LTE) in thermal plasma has been widely accepted. Most of the simulation models for the arc plasma torch are based on the hypothesis of LTE and its results indicate good validity to mimic the pattern of plasma flow inside a plasma torch. However, according to the LTE hypothesis, electrical conductivity near electrodes is significantly lower because of the low gas temperature. Consequently, it is difficult for electrical current flows to pass between the anode and cathode. Therefore, the key subject for a model concentrating on the LTE assumption is to deal with the low electrical conductivity near the electrodes. In this study, two models determining the electrical conductivity at the vicinity of the electrodes with two different assumptions were used to calculate the flow patterns inside a non-transferred DC arc plasma torch. Gas temperature, velocity, voltage drop, and heat energy of the plasma arc were compared between the two models. The results indicated that the plasma arc inside the plasma torch fluctuates, as simulated by both models. It seems that the model can obtain comparable accuracy with the experimental results if the plasma gas electrical conductivity is determined by nominal electron temperature. 相似文献
79.
Kondo T Kaburagi Y Shibata M Kurokawa C Inoue Y Yamamoto Y Miyazaki M 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2012,53(2):75-84
A simple clean-up method was developed for the simultaneous determination of pesticide residues in livestock products by GC-MS/MS. The pesticide residues were extracted with acetonitrile-ethanol (1 : 1), and matrix components such as adipose were effectively eliminated by a combination of refrigerated centrifugation, dispersive solid-phase extraction, and multifunctional column chromatography. In this method, samples are treated quickly and easily without the need for gel-permeation chromatography. Among 131 pesticides tested, 115 showed recovery within the range from 70 to 120%, with relative standard deviations of less than 15%. The quantification limits for the 115 pesticides in livestock products were 0.001 to 0.01 μg/g. 相似文献
80.
Yamamoto Y 《Chemical reviews》2012,112(8):4736-4769