生物机械学研究在康复工程中的应用

本文介绍了生物机械学及其在与运动功能康复有关的康复工程中的应用。以实例的形式给出了生物机械学在大腿假肢使用者滑倒问题中的生物机械学研究及其应用。康复工程与许多学科有关,其中运动功能康复与生物机械学关联性很强。康复工程中的生物机械学研究包括人体运动的功能模型,人与机械系统的交互原理与方法,人机结合界面,机械与人体功能的相互影响,人机一体化系统的设计与性能评定。这些问题的研究为运动功能康复提供了理论、方法和技术支撑;反之,康复工程又是生物机械学的重要应用领域,康复工程的需求促进生物机械学的发展,并为其提供活力。

脊髓空洞症空腔引流方法探讨

将脊髓空洞切开并行蛛网膜下腔引流是一百多年的传统方法。Ａｂｂｅ于１８９２年首先施行，１９２６年Ｐｕｕｓｅｐｐ把这种手术命名为Ｐｕｕｓｅｐｐ手术〔１，２〕。空洞引流物曾采用：硬脊膜条、橡胶、塑料、肠线、丝线、银金属线等或把银夹夹在伤口边缘。目前主要用硅...

手指何以如此灵活

用手指触摸、敲击物体表面,是我们日常生活的必须动作。殊不知,这些看似不起眼的动作,其完成过程却极其复杂,需要大脑、神经以及手部肌肉的精密协作。当注视自己的双手的时候,也许我们意识不到这是大自然生物机械学的杰作。我们也尚未真正了解手是如何受神经控制的,疾病是如何削弱其功能的。

Effect of thermo-mechanical processing on microstructure and electrochemical behavior of Ti-Nb-Zr-V new metastable β titanium biomedical alloy

The influence of thermo-mechanical processing (TMP) on the microstructure and the electrochemical behavior of new metastableβ alloy Ti?20.6Nb?13.6Zr?0.5V (TNZV) was investigated. The TMP included hot working in belowβ transus, solution heat treatments at the same temperature and different cooling rates in addition to aging. Depending upon the TMP conditions, a wide range of microstructures with varying spatial distributions and morphologies of equiaxed/elongatedα andβ phases were attained, allowing for a wide range of electrochemical properties to be achieved. The corrosion behavior of the studied alloy was evaluated in a Ringer’s solution at 37 °C via open circuit potential?time and potentiodynamic polarization measurements.

Mechanistic considerations for the use of monoclonal antibodies for cancer therapy

Since the approval of rituximab in 1997, monoclonal antibodies(mAbs) have become an increasingly important component of therapeutic regimens in oncology. The success of mAbs as a therapeutic class is a result of great strides that have been made in molecular biology and in biotechnology over the past several decades. Currently, there are 14 approved mAb products for oncology indications, and there are ten additional mAbs in late stages of clinical trials. Compared to traditional chemotherapeutic agents, mAbs have several advantages, including a long circulating half-life and high target specificity. Antibodies can serve as cytotoxic agents when administered alone, exerting a pharmacologic effect through several mechanisms involving the antigen binding(Fab) and/or Fc domains of the molecule, and mAbs may also be utilized as drug carriers, targeting a toxic payload to cancer cells. The extremely high affinity of mAbs for their targets, which is desirable with respect to pharmacodynamics(i.e., contributing to the high therapeutic selectivity of mAb), often leads to complex, non-linear, target-mediated pharmacokinetics. In this report, we summarize the pharmacokinetic and pharmacodynamics of mAbs that have been approved and of mAbs that are nearing approval for oncology indications, with particular focus on the molecular and cellular mechanisms responsible for their disposition and efficacy.

A New Type Machine of Mixing-molding for Polyblends

This paper introduces a new type machine for polyblends with excellent mixing capabilities of internal mixer and continuous molding character of extruder.The machine includes two functions - mixing and extrusion molding that have been composed together by rational design,so a tandem production mode - "batch + continuous" are opened up.The mathematical model of continuous mixing molding was established and verified availably by experimental research.The main physical mechanical property of vulcanizate,which had met national waterproof material standard,verified the machine practicability.The essential difference from other similar type machines is that this machine is not only suitable in producing granular and powder rubbers but also lumpish rubbers.

Aurora A orchestrates entosis by regulating a dynamic MCAK-TIP150 interaction

Entosis, a ceU-in-ceU process, has been implicated in the formation of aneuploidy associated with an aberrant cell division control. Microtubule plus-end-tracking protein TI P150 facilitates the loading of MCAK onto the microtubule plus ends and orchestrates micro- tubule plus-end dynamics during cell division. Here we show that TIP150 cooperates with MCAK to govern entosis via a regulatory cir- cuitry that involves Aurora A-mediated phosphorylation of MCAK. Our biochemical analyses show that MCAK forms an intra-molecular association, which is essential for TIP150 binding. Interestingly, Aurora A-mediated phosphorylation of MCAK modulates its intra-mo- lecular association, which perturbs the MCAK-TI P150 interaction in vitro and inhibits entosis in vivo. To probe if MCAK-TIP150 inter- action regulates microtubule plasticity to affect the mechanical properties of ceUs during entosis, we used an optical trap to measure the mechanical rigidity of live MCF7 ceils. We find that the MCAK cooperates with TIP150 to promote microtubule dynamics and modulate the mechanical rigidity of the cells during entosis. Our results show that a dynamic interaction of MCAK-TI P150 orchestrated by Aurora A-mediated phosphorylation governs entosis via regulating microtubule plus-end dynamics and cell rigidity. These data reveal a previously unknown mechanism of Aurora A regulation in the control of microtubule plasticity during ceU-in-ceU pro- cesses.

Designing the mechanical properties of peptide-based supramolecular hydrogels for biomedical applications

Hydrogels are a class of special materials that contain a large amount of water and behave like rubber.These materials have found broad applications in tissue engineering,cell culturing,regenerative medicine etc.Recently,the exploration of peptide-based supramolecular hydrogels has greatly expanded the repertoire of hydrogels suitable for biomedical applications.However,the mechanical properties of peptide-based hydrogels are intrinsically weak.Therefore,it is crucial to develop methods that can improve the mechanical stability of such peptide-based hydrogels.In this review,we explore the factors that determine or influence the mechanical stability of peptide-based hydrogels and summarize several key elements that may guide scientists to achieve mechanically improved hydrogels.In addition,we exemplified several methods that have been successfully developed to prepare hydrogels with enhanced mechanical stability.These mechanically strong peptide-based hydrogels may find broad applications as novel biomaterials.It is still challenging to engineer hydrogels in order to mimic the mechanical properties of biological tissues.More hydrogel materials with optimal mechanical properties suitable for various types of biological applications will be available in the near future.

Biomechanism of impact resistance in the woodpecker's head and its application

The woodpecker does not suffer head/eye impact injuries while drumming on a tree trunk with high acceleration （more than 1000xg） and high frequency. The mechanism that protects the woodpecker＇s head has aroused the interest of ornithologists, biologists and scientists in the areas of mechanical engineering, material science and electronics engineering. This article reviews the literature on the biomechanisms and materials responsible for protecting the woodpecker from head impact injury and their applications in engineering and human protection.

Three-dimensional finite element analysis of lumbar vertebra loaded by static stress and its biomechanical significance

Objective： To explore the mechanical behavior of lumbar spine loaded by stress and provide the mechanical basis for clinical analysis and judgement of lumbar spine fracture classification, mechanical distribution and static stress. Methods： By means of computer simulation method, the constructed lumbar spine three-dimensional model was introduced into three-dimensional finite element analysis by software Ansys 7.0. The lumbar spine mechanical behavior in different parts of the stress loading were calculated. Impact load is 0-8000 N. The peak value was 8000 N. The loading time is 0-40 minutes. The values of the main stress, stress distribution and the lumbar spine unit displacement in the direction of main stress were analyzed. Results： The lumbar spine model was divided into a total of 121 239 nodes, 112 491 units. It could objectively reflect the true anatomy of lumbar spine and its biomechanical behavior and obtain the end-plate images under different stress. The stress distribution on the lumbar intervertebral disc （L3-L4） under the axial, lateral flexion and extension stress, and the displacement trace of the corresponding processus articularis were analyzed. Conclusion： It is helpful to analyze the stress distribution of lumbar spine and units displacement in static stress loading in the clinical research of lumbar spine injury and the distribution of internal stress.