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41.
姜长丹 《辽东学院学报(自然科学版)》2004,11(4):76-77
人体小腿三头肌向下合成一条粗大的肌腱--跟腱,它止于跟结节,是小腿三头肌与跟骨连接的桥梁,在人体完成走、跑、跳等运动过程中起到至关重要的作用。运动中踝关节由跖伸状态突然过度到跖屈时,小腿三头肌被动拉长且猛烈收缩容易导致跟腱断裂。 相似文献
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Anisotropic Hybrid Hydrogels with Superior Mechanical Properties Reminiscent of Tendons or Ligaments
Mimicking the hierarchically anisotropic structure and excellent mechanical properties of natural tissues, such as tendons and ligaments, using biomaterials is challenging. Despite recent achievements with anisotropic hydrogels, limitations remain because of difficulties in achieving both structural and mechanical characteristics simultaneously. A simple approach for fabricating hybrid hydrogels with a hierarchically anisotropic structure and superior mechanical properties that are reminiscent of tendons or ligaments is proposed. Alginate–polyacrylamide double‐network (DN) hydrogels incorporated with high aspect ratio mesoporous silica microparticles are stretched and fixed via subsequent drying and ionic crosslinking to achieve multiscale structures composed of an anisotropically aligned polymer network embedded with aligned microparticles. The mechanical properties of hydrogels can be further controlled by the degree of stretching, quantities, and functional groups of inorganic microparticles, and types of crosslinking cations. The subsequent reswelling results in a high water content (>80%) similar to that of natural tendons while high strength, modulus, and toughness are maintained. The optimized anisotropic hybrid hydrogel exhibits a tensile modulus of 7.2 MPa, strength of 1.3 MPa, and toughness of 1.4 MJ m?3 even in the swollen state, which is 451‐, 27‐, and 2.2 times higher than that observed in the non‐swollen tough DN hydrogel. This study suggests a new strategy for fabricating anisotropic hydrogels with superior mechanical properties to develop new biomaterials for artificial tendons or ligaments. 相似文献
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采用左旋聚乳酸(PLLA)为基材研究静电纺丝工艺过程对聚乳酸纤维形貌和性能的影响,主要包括环境湿度、纺丝溶液浓度、接收转速、收集距离、注射泵推注速度、附加电压等过程参数。结果表明,接收转速与纺丝液浓度分别是影响纤维定向排列程度和纤维直径的最主要因素,其次是接收距离、环境湿度、推注速度。当聚乳酸-氯仿溶液聚合物质量浓度为80 mg/mL、纺丝电压为25 kV、接收距离为20 cm、注射泵推注速度为0.3 μL/s以及接收转速为1500 r/min时,纤维取向性良好,平均直径为(0.94±0.21) μm,可达到模拟肌腱组织天然细胞外基质结构的要求。 相似文献
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Jarau S Hrncir M Ayasse M Schulz C Francke W Zucchi R Barth FG 《Journal of chemical ecology》2004,30(4):793-804
By depositing scent marks on flowers, bees reduce both the search time and the time spent with the handling of nonrewarding flowers. They thereby improve the efficiency of foraging. Whereas in honey bees the source of these scent marks is unknown, it is assumed to be the tarsal glands in bumble bees. According to histological studies, however, the tarsal glands lack any openings to the outside. Foragers of the stingless bee Melipona seminigra have previously been shown to deposit an attractant pheromone at sugar solution feeders, which is secreted at the tips of their tarsi. Here we show that the claw retractor tendons have specialized glandular epithelia within the femur and tibia of all legs that produce this pheromone. The secretion accumulates within the hollow tendon, which also serves as the duct to the outside, and is released from an opening at the base of the unguitractor plate. In choice experiments, M. seminigra was attracted by feeders baited with pentane extracts of the claw retractor tendons in the same way as it was attracted by feeders previously scent marked by foragers. Our results resolve the seeming contradiction between the importance of foot print secretions and the lack of openings of the tarsal glands. 相似文献
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CFRP筋夹片-黏结型锚具的研制 总被引:2,自引:0,他引:2
提出了一种预应力碳纤维增强塑料(carbon fiber reinforced polymer,CFRP)筋夹片-黏结型锚具系统,通过静载锚固性能试验,研究了不同几何参数对其锚固性能的影响.试验结果表明,通过试验改进后的夹片-黏结型锚具能有效地锚固试验中所用的CFRP筋. 相似文献
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