非侵入式角膜在体弹性测量具有重要临床意义却尚无金标准。提出了基于光学相干层析(OCT)的光学相干弹性成像方法(OCE),实现了微气体(压强为10~40 Pa)脉冲激励下软组织的亚纳米-微米级振幅力学响应的高分辨观测。结合时域恢复曲线拟合模型(R-Model)和频域单自由度振动模型(SDOF-Model),测量了浓度(质量分数)为1.0%~2.0%的琼脂仿体和两名志愿者角膜的固有频率。测量结果表明:固有频率值不受激励压强大小的影响,且与杨氏模量的平方根正相关(皮尔逊相关系数为r≥0.98);SDOF-Model具有更好的可重复性,其平均离散系数(CV)为0.9%(琼脂仿体)和1.7%(人眼角膜),而R-Model的平均CV则高达8.4%(琼脂仿体)和42.6%(人眼角膜),即基于SDOF-Model的微激励OCE方法更适合人眼角膜固有频率的在体测量。

利用逆向工程与3D打印技术定制了患者的胫骨干骨折模型，对Orthofix单边外固定器固定胫骨干骨折方式的生物力学进行了研究。通过设计正交试验方案，采用XTDIC三维全场变形测量系统对Schanz钉在针夹上的分布、最外侧Schanz钉到骨折断端的距离、胫骨到外固定器的距离三种因素对Schanz钉的变形进行了测量。实验结果表明：当Schanz钉数量较少时，在压力载荷作用下会造成Schanz钉的弯曲变形增大，增加了外固定器塑性变形及疲劳断裂的可能性。根据综合九种方案的力学分析结果，外固定器到胫骨的距离对Schanz钉的变形影响最显著。当在针夹上安装6根Schanz钉，外侧Schanz钉到骨折断端的距离为120 mm和外固定器到胫骨的距离为30 mm时的方案综合性能最优。

The ocular lens stifiens dramatically with age, resulting in a loss of function. However, the mechanism of stifiening remains unknown, at least in part due to di±culties in making reliable measurements of the intrinsic mechanical properties of the lens. Recent experiments have employed manual compression testing to evaluate the stifiness of murine lenses which have genotypes pertinent to human lens diseases. These experiments compare the extrinsic stifiness of lenses from the genotype of interest to the wild-type lens in an efiort to reach conclusions regarding the cellular or molecular basis of lens stifiening. However, these comparisons are confounded by alterations in lens size and geometry which invariably accompany these genetic manipulations. Here, we utilize manual lens compression to characterize the stifiness of a porcine lens and a murine lens. An inverse elastographic technique was then developed to estimate the intrinsic shear modulus of each lens as well as the elastic modulus of the lens capsule. The results were in good agreement with the previous literature values.

采用三维重建方法--面绘制立方体算法(MC)体绘制构建人体腰椎L3~L4腰骶段的有限元模型, 并模拟添加前韧带、后韧带、黄韧带、纤维环等主要脊椎附着软组织, 精确构建了脊柱一体化三维有限元模型, 然后进行有限元模型网格化划分并设置各部分相应的材料属性。定义不同方向的载荷和边界条件以模拟正常模型和椎间盘膨出退化模型在不同工况下所承受的应力和形变情况, 通过分析其生物力学特性, 可以为临床上椎间盘膨出和椎间盘突出等的诊治提供生物力学依据。

T细胞的抗原识别和活化可以直接影响整个免疫应答的性质、效能和结果, 在人体免疫反应中具有核心作用。细胞的形态结构和力学特性决定着细胞的功能的发挥。利用原子力显微镜(AFM)从纳米水平和皮牛顿量级探测分析静息的T细胞和不同刺激剂(超抗原SEA和植物凝集素PHA)活化的T细胞的形态结构和生物力学特性。研究发现静息的T细胞呈较为规则的圆形, 细胞表面相对光滑均一, 活化后细胞高度和体积明显增大, 体积增大为静息T细胞的2~3倍, 高度增加了约50%, 这是T细胞经过刺激剂活化后增殖、分化而增大的表现。同时发现活化后的T细胞表面粗糙度增大, 细胞表面形成100 nm~1 μm颗粒状团簇结构。这种微纳结构域的形成与T细胞经过活化后细胞表面分子表达和细胞因子的分泌有关, 并且与免疫突触的形成和功能发挥密切关联。经过PHA和SEA活化后的T细胞表面粘附力增大, 是静息的T细胞的3-6倍, 而细胞硬度明显减小, 这种力学特性的变化有利于T细胞与病原体的相关作用从而清除病原体。通过AFM的研究, 可以进一步的了解T淋巴细胞形态变化与细胞行为之间的关系, 为更好地理解T细胞的结构与功能提供了更多可视化的依据。

Fiber optic sensors have a set of properties that make them very attractive in biomechanics. However, they remain unknown to many who work in the field. Some possible causes are scarce information, few research groups using them in a routine basis, and even fewer companies offering turnkey and affordable solutions. Nevertheless, as optical fibers revolutionize the way of carrying data in telecommunications, a similar trend is detectable in the world of sensing. The present review aims to describe the most relevant contributions of fiber sensing in biomechanics since their introduction, from 1960s to the present, focusing on intensity-based configurations. An effort has been made to identify key researchers, research and development (R&D) groups and main applications.

With the development of optical coherence tomography, the application optical coherence elastography (OCE) has gained more and more attention in biomechanics for its unique features including micron-scale resolution, real-time processing, and non-invasive imaging. In this review, one group of OCE techniques, namely dynamic OCE, are introduced and discussed including external dynamic OCE mapping and imaging of ex vivo breast tumor, external dynamic OCE measurement of in vivo human skin, and internal dynamic OCE including acoustomotive OCE and magnetomotive OCE. These techniques overcame some of the major drawbacks of traditional static OCE, and broadened the OCE application fields. Driven by scientific needs to engineer new quantitative methods that utilize the high micron-scale resolution achievable with optics, results of biomechanical properties were obtained from biological tissues. The results suggest potential diagnostic and therapeutic clinical applications. Results from these studies also help our understanding of the relationship between biomechanical variations and functional tissue changes in biological systems.

介绍了激光全息-散斑法用于人体腰椎损伤后,内固定装置稳定性生物力学实验。分析了对椎间盘表面位移和变形的测量。对标本制备、加载装置、光路系统、实验方案设计及实验过程均进行了介绍。激光全息-散斑法具有精度高、全场、非接触测量的特点,实验结果表明,在模型模拟腰椎生理运动的大变形过程中,能够测得模型在不同运动位置时椎间盘表面发生的微小三维位移,并由位移求出椎间盘的变形,从而为不同内固定方式的稳定性对比分析提供依据。

目的:研究人工椎间盘力学结构特点,探讨改进设计优化结构的依据.方法:在用有限元法进行正压下力学分析的基础上,对模型不同构件进行拓扑优化分析.结果:获得正压下假体模型主应力、作用力及支座反力的特点;指明拓扑优化的几何区域.结论:人工椎间盘的设计改进要在相关力学分析的基础上进行;通过优化分析既指明了假体结构上的重要区域,也显示出模型不同空间位置的可优化程度,为改进设计提供初步参考依据.有限元优化设计是假体研究、设计中经济有效的辅助方法.