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1.
In this work, we explored the osteogenic potential of freeze-dried cancellous bone allograft loaded with autologous mesenchymal stem cells (MSCs). Human MSCs were isolated, purified and identified. Flow cytometry revealed that the isolated and enriched cells were 90–97% homogeneous and were negative for reactivity to antigens CD34 and CD45 but positive for reactivity to antigen CD44. The expressions of transformation growth factor-β1 (TGFβ1) and basic fibroblast growth factor (bFGF) were detected as positive in freeze-dried cancellous bone allograft using the immunohistochemistry method. The expression of Alkaline Phosphatase (AKP) and Type I collagen mRNA in MSCs, co-cultured in supernatant of allograft, showed a stronger positive than that in hydroxyapatite (HA). After 1 day of incubation, MSCs grew in both surface and inner pores of bone allograft blocks observed by electron microscopy scan. The composites of allograft loaded with MSCs or HA loaded with MSCs were implanted in nude mice subcutaneously. Osteoid and fluorescence labeling were observed in the allograft by the 4th and 6th weeks, respectively, but not at any time in the HA. This study suggests that the freeze-dried cancellous bone allograft would be an ideal choice for the delivery of mesenchymal stem cells for bone tissue engineering applications.  相似文献
2.
橡胶隔振器设计开发研究   总被引:2,自引:0,他引:2  
提出以有限元方法为基础的橡胶隔振器设计开发流程,并以某船用柴油机隔振器为对象,详细阐述了开发设计过程。介绍橡胶有限元的基本理论,通过有限元计算分析该橡胶隔振器的结构,预估橡胶材料的硬度,并根据设计目标对其结构进行一定的修改。通过加工试制及试验测试,所得结果与有限元计算结果吻合较好。  相似文献
3.
等离子喷涂抗菌羟基磷灰石涂层研究   总被引:2,自引:0,他引:2       下载免费PDF全文
以磷酸锆载银抗菌剂作为添加剂,制备真空等离子喷涂抗菌羟基磷灰石(HA)涂层,并对涂层的形貌、组成、结合强度以及抗菌性能进行研究.结果表明,添加抗菌剂的HA涂层形貌没有发生明显改变.当添加剂含量较大时(10wt%),涂层中出现少量反应产物CaZr(PO4)2与Na6CaP2O9.掺入抗菌剂之后涂层的结合强度呈上升趋势,而且随着抗菌剂百分比的增加,涂层结合强度随之增大.含抗菌剂5wt%以上的HA涂层对牙龈单胞卟啉菌(Pg)、具核梭杆菌(Fn)及伴放线杆菌(Aa)具有明显的抗菌作用,抗菌力大小依次为Pg〉Fn〉Aa.  相似文献
4.
探析热电制冷   总被引:2,自引:0,他引:2  
本文指出热电制冷是2l世纪极有发展前景的制冷新技术,但目前发展水平还不够高。由于制冷系数低、性能价格比较低及对电源要求较高等因素,目前发展受到了制约。新材料、新工艺、新技术及新电源的突破发展,是热电制冷进入一般工业和家庭生活的前提。  相似文献
5.
Nb、Ti微合金化新型440MPa级船用钢板韧性研究   总被引:1,自引:1,他引:0  
凌纯 《材料开发与应用》2011,26(2):60-62,74
研究了某钢厂热连轧TMCP工艺14mm厚440MPa级钢板的强韧性,对微观组织进行了观察分析。试验结果表明,新型热连轧440MPa钢板具有良好的低温韧性,-40℃冲击功超过310 J,韧脆转变温度低于-100℃。新型440MPa钢板良好的性能来源于低碳、Nb-Ti微合金化成分设计及TMCP工艺下获得细化的针状铁素体组织。  相似文献
6.
How to moderate ship the damages caused by the underwater explosions is of great interest to the modern ship designers. This investigation explores the protective effects of a layer of rubber sandwich with the square honeycomb core coated onto ship hull. Two slender steel scaled ship models were manufactured and tested. One model was coated with a layer of rubber coating while the other kept intact. A series of comparative tests were carried out to comprehend the dynamic performance of the protective layer when both shock wave and bubble pulse loading were considered. Modal characteristics of both models were measured firstly and then live UNDEX tests were made on the free floating ship models. The acceleration and strain peaks were selected as the major comparative criterions. The free field and wall pressure were also monitored. Detailed discussions on test results show that the protective rubber layer is capable of moderating damage of the ship body caused by shock wave while not very effective in reducing the whipping damage excited by bubble pulse.  相似文献
7.
“海洋六号”船人性化设计   总被引:1,自引:0,他引:1       下载免费PDF全文
简要介绍了船的总体设计及其建成后的实船性能,并对国内外近期建成的海洋调查船进行了主要性能数据比较,从中可以看到"海洋六号"船在某些关键技术性能方面处领先水平。  相似文献
8.
Hydroxyapatite-containing titania coatings on titanium substrates were formed by micro-arc oxidation (MAO) in electrolyte containing calcium acetate monohydrate (CH3COO)2Ca·H2O) and sodium phosphate monobasic dihydrate (NaH2PO4·2H2O) using a pulse power supply. Scanning electron microscopy (SEM) with Energy dispersive X-ray spectrometer (EDX) and X-ray diffraction (XRD) were employed to characterize the microstructure, elemental composition and phase components of the coatings. The coatings were rough and porous, without apparent interface to the titanium substrates. All the oxidized coatings contained Ca and P as well as Ti and O, and the porous coatings were made up of anatase, rutile and hydroxyapatite. Such MAO films are expected to have significant applications as artificial bone joints and dental implants.  相似文献
9.
二维层状地基波阻板隔振分析   总被引:1,自引:0,他引:1  
为了研究层状地基中波阻板的隔振效果,基于薄层法在研究层状介质中波的传播问题的高效性、边界单元法处理无限域问题的精确性,结合两种方法的优点,本文采用以薄层法层状半空间基本解答作为格林函数的边界元法,分别对上软下硬和上硬下软两种层状半空间地基中波阻板的隔振效果进行分析。研究表明:增加波阻板的厚度、提高波阻板的弹性模量可以显著提高隔振效果;分层土体厚度和土性对于水平和竖向的位移振幅衰减系数有较大影响。  相似文献
10.
减振阻尼材料纳米改性试验研究   总被引:1,自引:0,他引:1  
聚合物混凝土是一种具有良好的耐久性(包括耐水、耐冻融、耐腐蚀等),力学性能(包括抗压、抗弯强度等)、阻尼特性的复合材料,广泛的应用于各个领域中。纳米粒子由于其尺寸非常的小,因此具有突出的表面效应、小尺寸效应和量子限域效应,具有异于普通材料的光、电、磁、热、力学、机械等性能,将纳米粒子成功的加入到聚合物混凝土中,在保证聚合物混凝土力学特性的前提下,大大提高聚合物混凝土的阻尼特性,改善聚合物混凝土的综合特性,形成减振降噪用纳米复合材料。  相似文献
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