假体隆乳术后形态不佳的矫治

目的探讨假体置入隆乳术后形态不佳的原因和矫治方法。方法根据临床表现将乳房不佳分为5种类型：圆球型、上部膨隆型、下坠型、单侧双乳型及不规则型。通过松解纤维囊、纤维囊折叠缝合、重新分离隆乳腔隙、更换假体、乳房悬吊术等方法，进行矫治再次隆乳术。结果经过至少6个月随访观察，本组106例均获得了满意的手术效果。结论隆乳术后乳房形态不佳主要与假体体积过大、腔隙分离不到位、假体移位、乳房下皱襞过度分离、纤维囊挛缩及引流、包扎位置不当等因素有关，针对不同原因实施相应的手术方法矫治，能够获得满意的手术效果。     

形状记忆合金环抱接骨板治疗锁骨骨折

目的 探讨形状记忆合金环抱接骨板治疗锁骨骨折的手术方法及疗效。方法 采用西脉记忆合金环抱接骨板治疗锁骨骨折54例。结果 54例病人全部获得随访，优良率96.3％。结论 形状记忆合金环抱接骨板治疗锁骨骨折是一种方便有效的方法，具有手术操作简便、内固定确实等优点，但应加强术后管理。     

新型记忆合金节段内固定器治疗腰椎峡部裂的实验研究

目的 :设计一种治疗腰椎峡部裂的新型记忆合金节段内固定器 ,测试其材料力学特性 ,并评价其生物力学稳定性。方法 :测量 2 0具干燥完整成人腰椎标本获得数据 ,按数据采用镍钛记忆合金设计固定器并行材料力学测试。取 6具新鲜成人腰椎标本 ,先后形成正常脊柱组、峡部裂组、横突棘突钢丝捆绑组、钩螺钉固定组、Buck螺钉固定组、新研制记忆合金固定器固定组 6组实验模型。利用脊柱三维运动实验机 ,分别测试 6组的前屈 /后伸、左 /右侧弯及左 /右轴向旋转 6种运动的活动范围。结果 :材料力学测试表明其形态记忆功能良好 ,体温状态下会产生稳定可靠的回复力。 6组在前屈、后伸及左右旋转状态 ,峡部裂组稳定性最差 ,同其他 5组差别明显。而使用新研制记忆合金内固定器组可明显恢复腰椎稳定性 ,同正常脊柱组及其他 3种内固定组均无显著差别。另两种状态左右侧弯 6组均无显著性差别。结论 :新设计的内固定器符合腰椎的生物力学要求 ,较先前的半环状内固定器优势明显 ,具有很好应用前景     

三种内固定治疗上肢长骨干骨折的临床比较研究

目的观察天鹅记忆接骨器(swan-likememoryconnector,SMC)治疗上肢长骨干骨折的疗效,并与加压接骨板(dynamiccompressiveplate,DCP)和带锁髓内针(lockedintramedullarynail,LIN)进行临床对比研究。方法随机选择1997年8月～2001年8月入院的新鲜上肢长骨干骨折148例,分别采用SMC(49例)与DCP(50例)、LIN(49例)进行内固定治疗,术后常规抗炎治疗1周,定期拍片并随访患肢功能恢复情况。结果SMC组的手术时间明显低于LIN组与DCP组(P<0.05),三组伤口感染率无差异。SMC组骨愈合时间和骨不连发生率显著短于DCP组和LIN组(P<0.05),而术后功能优良率高于DCP组和LIN组。在SMC固定下,骨折愈合直接由解剖型或类解剖型的骨样骨板状直接替代连接,固定段无应力遮挡和骨质疏松。结论SMC是治疗上肢长骨干骨折的有效方法,优于DCP和LIN。SMC的几何构形和力学特性有利于骨折愈合。在本器固定下,可能存在一种新的尚未被认知的骨折愈合方式。     

Trajectory of contact region on the fingerpad gives the illusion of haptic shape

When one explores a solid object with a fingertip, a contact region is usually defined. When the trajectory of this region on the fingerpad is artificially controlled so as to resemble the trajectory that is normally present while exploring a real object, the experience of shape is created. In order to generate appropriate local deformation trajectories, we built a servo-controlled mechanism that rolled a flat plate on the fingerpad during the manual exploration of virtual surfaces so that the plate was kept tangent to a virtual shape at the point of virtual contact. An experiment was then designed to test which mode of exploration maximized the shape information gain: active versus semi-active exploration, where semi-active exploration is when one hand touches passively and the other moves the target object, and the use of single versus multiple points of contact. We found that subjects were able to perform curvature discrimination at levels comparable to those achieved when using direct manual contact with real objects, and that the highly simplified stimulus provided by the device was a sufficient cue to give the illusion of touching three-dimensional surfaces.     

The Topography of Non-Linear Cortical Dynamics at Rest, in Mental Calculation and Moving Shape Perception

Differential cortical activation by cognitive processing was studied using dimensional complexity, a measure derived from nonlinear dynamics that indicates the degrees of freedom (complexity) of a dynamic system. We examined the EEG of 32 healthy subjects at rest, during a visually presented calculation task, and during a moving shape perception task. As a nonlinear measure of connectivity, the mutual dimension of selected electrode pairs was used. The first Lyapunov coefficient was also calculated. Data were tested for non-linearity using a surrogate data method and compared to spectral EEG measures (power, coherence). Surrogate data testing confirmed the presence of nonlinear structure in the data. Cognitive activation led to a highly significant rise in dimensional complexity. While both tasks activated central, parietal and temporal areas, mental arithmetic showed frontal activation and an activity maximum at T3, while the moving shape task led to occipital activation and a right parietal activity maximum. Analysis of mutual dimension showed activation of a bilateral temporal-right frontal network in calculation. The Lyapunov coefficent showed clear topographic variation, but was not significantly changed by mental tasks (p<.09). While dimensional complexity was almost unrelated to power values, nonlinear (mutual dimension) and linear (coherence) measures of connectivity shared up to 37% of variance. Data are interpreted in terms of increased cortical complexity as a result of recruitment of asynchronously active, distributed neuronal assemblies in cognition. The topography of nonlinear dynamics are related to neuropsychological and neuroimaging findings on mental calculation and moving shape perception.     

材料参数与镍钛形状记忆合金的本构关系

在Ｔａｎａｋａ模型基础上，我们讨论了形状记忆合金热力学特性的本构关系。特别注意了桓温拉伸过程和强迫回复过程。本构方程的材料参数，即弹性模量Ｄ，变化张量Ω，热力弹性张量均以镍钛合金实验测试值来确定。在不同的应力－应变－温度关系试验中发现Ｄ和Ω与温度之间有很强的相关性。     

Fourier变换形状测试法测量关节面形状

本文应用富里叶变换形状测试技术（ＦＴＰ），针对人体关节测试研究，并从实际应用角度分析了ＦＴＰ技术的误差及其改进方法，对标准平板和标准圆柱面的测定结果表明，精度可以达到０．０５ｍｍ以上。     

Finite element analysis and fatigue of stents

Understanding the behaviour of implantable medical devices is of obvious importance. The potential for failure of a medical device can often be associated with issues related to cyclic loading of the device, and material fatigue. Detailed finite element simulations to evaluate the fatigue of stents allow the engineer to assess potential failures. The engineer can then use the analysis results to modify the design and prevent failure, without making and testing numerous physical devices. Complete understanding of the mechanical behaviour of a stent provided by finite element analysis has the benefits of facilitating effective design, helping to reduce time to market and minimising the potential for unwanted failures.     

4D hyperspherical harmonic (HyperSPHARM) representation of surface anatomy: A holistic treatment of multiple disconnected anatomical structures

Image-based parcellation of the brain often leads to multiple disconnected anatomical structures, which pose significant challenges for analyses of morphological shapes. Existing shape models, such as the widely used spherical harmonic (SPHARM) representation, assume topological invariance, so are unable to simultaneously parameterize multiple disjoint structures. In such a situation, SPHARM has to be applied separately to each individual structure. We present a novel surface parameterization technique using 4D hyperspherical harmonics in representing multiple disjoint objects as a single analytic function, terming it HyperSPHARM. The underlying idea behind HyperSPHARM is to stereographically project an entire collection of disjoint 3D objects onto the 4D hypersphere and subsequently simultaneously parameterize them with the 4D hyperspherical harmonics. Hence, HyperSPHARM allows for a holistic treatment of multiple disjoint objects, unlike SPHARM. In an imaging dataset of healthy adult human brains, we apply HyperSPHARM to the hippocampi and amygdalae. The HyperSPHARM representations are employed as a data smoothing technique, while the HyperSPHARM coefficients are utilized in a support vector machine setting for object classification. HyperSPHARM yields nearly identical results as SPHARM, as will be shown in the paper. Its key advantage over SPHARM lies computationally; HyperSPHARM possess greater computational efficiency than SPHARM because it can parameterize multiple disjoint structures using much fewer basis functions and stereographic projection obviates SPHARM’s burdensome surface flattening. In addition, HyperSPHARM can handle any type of topology, unlike SPHARM, whose analysis is confined to topologically invariant structures.