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Comparison of physical, chemical and cellular responses to nano- and micro-sized calcium silicate/poly(epsilon-caprolactone) bioactive composites. 下载免费PDF全文
Jie Wei S J Heo D H Kim S E Kim Y T Hyun Jung-Woog Shin 《Journal of the Royal Society Interface》2008,5(23):617-630
In this study, we fabricated nano-sized calcium silicate/poly(epsilon-caprolactone) composite (n-CPC) and micro-sized calcium silicate/poly(epsilon-caprolactone) composite (m-CPC). The composition, mechanical properties, hydrophilicity and degradability of both n-CPC and m-CPC were determined, and in vitro bioactivity was evaluated by investigating apatite forming on their surfaces in simulated body fluid (SBF). In addition, cell responses to the two kinds of composites were comparably investigated. The results indicated that n-CPC has superior hydrophilicity, compressive strength and elastic modulus properties compared with m-CPC. Both n-CPC and m-CPC exhibited good in vitro bioactivity, with different morphologies of apatite formation on their surfaces. The apatite layer on n-CPC was more homogeneous and compact than on m-CPC, due to the elevated levels of calcium and silicon concentrations in SBF from n-CPC throughout the 14-day soaking period. Significantly higher levels of attachment and proliferation of MG63 cells were observed on n-CPC than on m-CPC, and significantly higher levels of alkaline phosphatase activity were observed in human mesenchymal stem cells (hMSCs) on n-CPC than on m-CPC after 7 days. Scanning electron microscopy observations revealed that hMSCs were in intimate contact with both n-CPC and m-CPC surfaces, and significantly cell adhesion, spread and growth were observed on n-CPC and m-CPC. These results indicated that both n-CPC and m-CPC have the ability to support cell attachment, growth, proliferation and differentiation, and also yield good bioactivity and biocompatibility. 相似文献
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M.?Gustavsson H.?Nagai T.?OkutaniEmail author 《International Journal of Thermophysics》2005,26(6):1803-1813
The thermal effusivity of drop-size liquids was measured by the pulse transient hot-strip technique. A strip sensor, used
as a thermometer and heat source, is deposited on a smooth surface of an electrically insulating background material – onto
which an insulating liquid sample is applied, completely covering the strip probe. Experiments can be made controlling the
thermal penetration depth to within some 10 μm of the liquid sample – here demonstrated by measuring a drop of water at about
1% uncertainty. Measurements were made on water and a series of silicone oils (kinematic viscosity from 5 to 50 cSt; 1 cSt = 10−6 m2· s−1) in microgravity conditions using a 10 m drop tower (10−3 g, 1.4 s), to investigate if any potential natural convection in the liquid at normal gravity condition is present, influencing
the results. However, no such influence was observed.
Paper presented at the Fifteenth Symposium on Thermophysical Properties, June 22–27, 2003, Boulder, Colorado, U.S.A. 相似文献
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微米金红石型TiO_2催化超声降解罗丹明B的研究 总被引:2,自引:0,他引:2
采用微米金红石型TiO2催化超声降解有机染料罗丹明B,考察了溶液pH、反应时间、催化剂投量、染料浓度、超声波功率和频率以及H2O2投量等因素的影响.结果表明,在溶液pH=5、罗丹明B初始浓度为10 mg=/L、TiO2投量为1 g/L、超声波功率为50 W、超声波频率为40kHz、体系温度为20℃的条件下,超声降解30 min时对罗丹明B的降解率可达58.37%.试验结果还表明,适当延长超声时间(40 min)和加入一定量的H2O2(3.5 mL/L),可大幅度提高对罗丹明B的降解率(分别可达76.54%和83.73%). 相似文献
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