Between-limb differences in running technique induces asymmetric negative joint work during running

Negative work, which is mainly generated by eccentric muscle contraction, has an important influence on the associated muscle damage. Generally, mechanical parameters are determined for one side of a lower extremity on the assumption of negligible between-limb differences. However, between-limb differences in the negative work of lower extremity joints during running remain unclear. This study examines between-limb differences in negative work and associated mechanical parameters during the contact phase of running. Twenty-five young adult males voluntarily participated in this study. Each participant was asked to run on a straight runway at a speed of 3.0?m?s^?1. Negative work, amplitude, duration of negative power, moment, and angular velocity were computed for both sides of the lower extremities. Significant differences were found in negative work between limbs for the hip (18.9?±?11.7%), knee (13.6?±?10.4%), and ankle (11.8?±?8.5%) joints. For the hip joint, asymmetric negative work was attributable to the between-limb difference in the amplitude of negative power owing to a corresponding difference in the moment. The between-limb differences concerning the duration and amplitude of negative power could explain the asymmetric negative work in the knee joint. The asymmetric negative work of the ankle joint was attributable to the between-limb difference in the amplitude and duration of the negative power and the moment. These results indicate that asymmetric negative work was generated in each lower extremity joint; however, the major mechanical parameters corresponding to the negative work are not the same across the joints.     

一种机载重轨InSAR高精度三维定位方法

在重轨干涉实际测量中,两次飞行航迹难以保持高度重合,飞行高度和姿态不稳定,干涉图像对存在明显不规则的相对形变,难以进行三维定位。通过分析重轨机载InSAR图像对的几何形变和形成原因,提出一种从精准的InSAR成像几何关系出发,通过修正成像参数,实现机载重轨InSAR高精度三维定位的方法。该方法通过引入地面控制点,实现干涉图像对精准的相对定位,生成高精度DEM;并利用高精度DEM,实现机载重轨InSAR高精度三维定位。对比检查点实测结果和定位结果,表明该方法可有效地解决机载重轨InSAR的三维定位困难的问题。     

Injectable hybrid inorganic nanoscaffold as rapid stem cell assembly template for cartilage repair

Cartilage injuries are often devastating and most cannot be cured because of the intrinsically low regenerative capacity of cartilage tissues. Although stem-cell therapy has shown enormous potential for cartilage repair, the therapeutic outcome has been restricted by low survival rates and poor chondrocyte differentiation in vivo. Here, we report an injectable hybrid inorganic (IHI) nanoscaffold that facilitates fast assembly, enhances survival and regulates chondrogenic differentiation of stem cells. IHI nanoscaffolds that strongly bind to extracellular matrix (ECM) proteins assemble stem cells through synergistic 3D cell–cell and cell–matrix interactions, creating a favorable physical microenvironment for stem-cell survival and differentiation in vitro and in vivo. Additionally, chondrogenic factors can be loaded into nanoscaffolds with a high capacity, which allows deep, homogenous drug delivery into assembled 3D stem-cell-derived tissues for effective control over the soluble microenvironment of stem cells. The developed IHI nanoscaffolds that assemble with stem cells are injectable. They also scavenge reactive oxygen species and timely biodegrade for proper integration into injured cartilage tissues. Implantation of stem-cell-assembled IHI nanoscaffolds into injured cartilage results in accelerated tissue regeneration and functional recovery. By establishing our IHI nanoscaffold-templated 3D stem-cell assembly method, we provide a promising approach to better overcoming the inhibitory microenvironment associated with cartilage injuries and to advance current stem-cell-based tissue engineering.     

基于FPGA技术的8B/10B信道编码设计

该文在分析8B/10B编码原理的基础上,设计了改进型8B/10B编码方案.该编码在完成高速数据信道编码功能的同时,可另外提供一路实时低速信道.基于FPGA技术采用查表法实现了改进型编解码电路,通过仿真验证了该编码方案的有效性,并在Spartan6系列FPGA中进行了综合测试.结果表明,此编解码方法占用的FPGA逻辑资源...     

研发外包中的关系契约

在研发项目外包合作关系中,缔约各方的行为不仅受正式契约规制,而且受非正式契约调节。后者对合作研发绩效尤其是持续合作有着重要影响。鉴于此,本文在"关系契约"概念基础上构建了一个研发项目外包者与承包者之间的重复博弈模型,分析研发项目外包合作关系中的非正式治理机制-关系契约的基本特征。结果表明,研发项目外包者和承包者之间的对称性关系契约只与技术成果价值的波动幅度有关,而与承包者的研发生产率系数及私人成本系数等特征参数无关。这对于关系契约的优化设计具有重要的参考价值。     

上海市2004年冬季城市大气气溶胶含Pb单颗粒物的来源查证

采用质子微探针技术，分析单个大气气溶胶颗粒物。将微束质子激发X射线分析(Micro-PIXE)同计算机模式识别技术结合，查证上海市2004年冬季城市大气气溶胶PM10中含Pb单颗粒物的来源。结果在上海大气气溶胶PM10中识别出七种铅污染排放源，它们分别是：汽车尾气，钢铁工业排尘，燃煤烟尘，土壤扬尘，柴油车尾气，助动车尾气和水泥尘。其中，钢铁工业排尘和燃煤排尘是禁止使用有铅汽油后上海市地区大气铅污染的最主要排放源。     

P企业规模、研发强度、资助强度与政府科技资助的绩效关系研究——基于浙江民营科技企业的实证研究/P P /P P/FONT /P

政府科技资助的绩效已经引起国内外学者的极大关注。本文基于文献研究,建立影响企业R&D投入的实证模型,采用浙江省民营科技企业数据,测度了政府科技资助对企业R&D投入的影响。进一步,分别从企业规模、研发强度、资助强度等不同视角研究政府科技资助的激励效应,探索政府科技资助的激励机理,研究发现：政府科技资助对企业滞后一年的R&D投入有显著促进作用;企业规模越大,政府科技资助激励效果越好;政府科技资助强度越大,激励效果越好;企业研发强度影响政府科技资助激励企业R&D投入。     

虚拟研发组织的知识转移机制:一个文献综述

从虚拟研发组织内部治理结构出发,着力探讨其中的知识转移机制,力求通过对相关文献的综述,理清虚拟研发组织知识转移理论的研究脉络,展示虚拟研发组织中知识转移的最新研究进展,指出其研究重点与难点并给出未来研究方向。     

劳伦斯与沈从文乡土情怀之比较

英国作家D.H.劳伦斯与中国作家沈从文都以自己的家乡为背景创作了大批优秀的"乡土作品"。稍事比较,不难看出劳伦斯与沈从文有着截然不同的乡土情怀:劳伦斯以犀利的笔调贬斥家乡习气之庸俗;沈从文以溢美之言赞颂故里民风之淳朴。然而,这种迥然不同的乡土情怀背后,却深藏着两位作家对生命本真回归作为的向往。     

木防己多糖的组成及其清除活性氧自由基的作用

目的:提取并纯化木防己多糖(AFMP),确定其组成,研究其清除活性氧自由基的作用.方法:利用水提醇沉得到木防己粗多糖,再经DEAE纤维素和聚酰胺纯制.利用Fenton反应研究AFMP清除·OH的作用;利用邻苯三酚自氧化法研究AFMP清除·O2-的作用.结果:纸色谱显示AFMP由葡萄糖和半乳糖组成.AFMP清除·OH的能力较弱;清除·O2-时的效果稍强,IC50为1407.4μg/ml.结论:木防己多糖为首次提取制得,有一定的清除羟自由基和超氧阴离子自由基的作用.