用循证医学证据指导股骨粗隆间骨折的治疗决策

用循证医学证据指导股骨粗隆间骨折的治疗决策,在权威评价系统中查询最佳证据。结果显示,外固定架和髁一头型钉不适用粗隆间骨折;DHS具有明显优势;不能证明人工关节置换和内固定何者占优。提示应用循证医学证据指导股骨粗隆间骨折的治疗决策,可以对患者实施个体化治疗。     

石河子地区老年人骨质疏松性骨折影响因素调查分析

分析石河子地区骨质疏松性骨折老年人的影响因素。采用现场调查的方法,对2010年10月～2011年7月在石河子大学医学院第一附属医院和石河子市人民医院住院的60岁及以上400名骨质疏松性骨折患者进行一对一问卷调查。单因素分析,性别、年龄、父亲髋部骨折史、母亲髋部骨折史、当前是否吸烟、糖尿病史、高血压病史、类风湿性关节炎病史、既往骨折史、是否每日饮用浓茶、是否进行体育锻炼是影响本地区骨质疏松性骨折的因素。多元线性逐步回归分析,性别、父亲髋部骨折史、母亲髋部骨折史、当前是否吸烟、类风湿性关节炎病史是影响本地区骨质疏松性骨折的主要因素。影响石河子地区骨质疏松性骨折的因素是多方面的,其影响因素可为干预本地区未骨折的社区老年高危人群提供科学参考依据。     

Thermal shock resistance of brittle ceramic materials with embedded elliptical cracks

An analytical model is established for the prediction of the thermal shock resistance of a ceramic plate with an embedded elliptical crack with ideal thermal insulation. The thermal stress intensity factors at the crack fronts are formulated by fitting the thermal stress to a polynomial form in an un-cracked plate. The thermal shock resistance of sapphire ceramic is evaluated as an example. In addition, the numerical solution of thermal shock resistance suitable for practical engineering applications is provided. The model developed applies to any brittle material in high temperature applications.     

Flaw tolerance promoted by dissipative deformation mechanisms between material building blocks

Novel high-performance composite materials often draw inspiration from natural materials such as bone or mollusc shells. A prime feature of such composites is that they are, like their natural counterparts, quasibrittle. They are tolerant to material flaws up to a certain characteristic flaw-tolerant size scale, exhibiting high strength and toughness, but start to behave in a brittle manner when sufficiently large flaws are present. Here, we establish that better flaw tolerance can be achieved by maximizing fracture toughness relative to the maximum elastic energy available in the material, and we demonstrate this concept with simple two-dimensional coarse-grained simulations where the transition from brittle to quasibrittle behaviour is examined.     

Ductile fracture mechanism in fine-grained magnesium alloy

The ductile fracture mechanism in a fine-grained magnesium alloy has been investigated by transmission electron microscopy-focused ion beam techniques. In coarse-grained or conventional magnesium alloys, twins form at the very beginning of the deformation process, and crack propagation occurs through the twin boundaries. However, in the alloy used in this study, subgrain structures were found instead of twins at the crack tip. Nanoscale twins formed subsequently owing to large stress in the crack propagation route. The fine-grained alloys showed high fracture toughness resulting from resistance to the twins at the beginning of the deformation.     

Deformation and failure of a heterogeneous high explosive

The deformation and failure of the pristine PBX 9501 high explosive are studied experimentally by combining Brazilian disk compression with the digital image correlation (DIC) technique. The Brazilian disk specimen was loaded by a pair of compressive forces across the diameter. The full-field deformation on the surface of the disk, during the loading process, was obtained using DIC on a series of random speckle images acquired during the test. In this series of experiments, we focused on the effect of temperature while keeping the loading speed quasi-static. Tests were conducted under three different temperatures, ?15°C, 23°C, and 50°C. For all testing conditions, it was observed that as the applied load reaches maximum, localized deformation starts at the two regions near the loading points. The localized deformation then proceeds along an irregular path toward the center of the specimen and coalesces. Finally, deformation of the Brazilian disk subjected to cyclic compressive load at ambient temperature was also measured and studied.     

Direct evidence that an apparent splitting pattern of gamma particles in Ni alloys is a stage of coalescence

High-resolution electron microscopy is used to determine the translation order domains of gamma particles in arrangements formed during Ostwald ripening in the alloy Ni-12at.%Al. Such arrangements have been often identified with the operation of a mechanism of particle splitting in the late stages of the coarsening process, that is when the elastic strain contribution becomes predominant. It is shown that the translation order domains are not identical in such a particle array. This leads to the conclusion that particle splitting is not necessarily the mechanism responsible for the formation of such characteristic particle arrangements. Instead, particle migration can also be considered to be the responsible mechanism for the formation of such a correlated gamma-particle spatial distribution observed in Ni-based alloys.     

谈《外科学》股骨干骨折肌肉牵拉移位表述存疑

股骨干骨折的两骨折端均受肌肉的牵拉,各不同部位可发生典型移位。我国本科教材《外科学》对其文字表述有9处存疑,即3处移位虚构不实、3处移位达意不清、3处移位被疏忽遗漏。流传达49年的示范插图有11处存疑,在肌肉动力、骨折定位、解剖方位、解剖形态、纵轴线等5个方面,欠缺认识而重复错绘。就文图20处存疑全方位坦诚探讨,必须重视基础理论,深入临床一线认真核查,弄清楚移位是怎样造成的,从而防范闭门造车及纸上谈兵,坚守真实底线,还原移位真相。

     

高龄股骨粗隆间骨折的治疗经验

探讨高龄患者粗隆间骨折的治疗,并观察比较股骨近端防旋髓内钉（proximal femoralnail anti—rotation,PFNA）和Gamma钉（Gamma Nail）在高龄患者粗隆间骨折治疗中的应用和疗效。经对81例高龄股骨粗隆间骨折行PFNA、Gamma内固定治疗,结果经术后1个月～24个月随访,PFNA...     

椎体成形术和球囊扩张椎体后凸成形术治疗骨质疏松性椎体压缩骨折的对比研究

为对比分析椎体成形术（PVP）与球囊扩张椎体后凸成形术（PKP）治疗骨质疏松性椎体压缩骨折的临床疗效。共治疗患者45例。PVP25例,PKP20例。所有患者术后疼痛均明显减轻或消失,PVP组与PKP组两组相比,术后的伤椎及相邻椎间隙高度、脊柱后凸Cobb角及ODI评分差异有统计学意义（P〈0．05）。PKP能够更好的恢复骨折椎体的高度,矫正脊柱后凸畸形,改善脊柱功能,明显减少骨水泥渗漏,临床效果较PVP更为满意。