Detachable shape-memory sewing ring for heart valves

The novel sewing ring concept consists of a detachable ring snap connection between valve housing or stent and suture cuff. The suture cuff itself is a memory metal ring of nickel-titanium (NiTi) that is embedded within a textile fabric torus. After a special training program the ring can assume two geometric shapes when alternately cooled and heated. Due to this physical property, the sewing ring can be safely fixed within a groove of the housing or stent by changing between room and physiological temperature. This allows the surgeon first to implant the sewing ring followed by arbitrary positioning and final fixation of the valve by the shape-memory effect. Additional advantages are an increased stiffening of the valve base for minimizing potential leaflet dysfunction, and reduced time and risk of implantation, particularly when a reoperation is necessary.     

Pseudoviral hollow-cored vesicles in multiple sclerosis brain

Summary Novel, superficially virus-like hollow-cored particles 50–60 nm in diameter were found in the perivascular extracellular space of the brain from a patient who died with acute multiple sclerosis (MS). It is concluded that they are not virions but are derived from myelin undergoing vesicular demyelination. This case demonstrates the need for caution in the interpretation of unusual electron microscopic appearances.     

应用内置钛镍记忆合金牵张器在下颌骨牵张成骨的初步研究

目的　探索利用钛镍记忆合金牵张成骨增高下颌牙槽嵴和修复下颌骨节段性缺损的可行性。方法　 2 0只成年杂种犬分为 5组 ,Ⅰ组和Ⅱ组进行牵引成骨增高下颌骨牙槽嵴 ,Ⅲ组和Ⅳ组进行牵引成骨修复下颌骨缺损 ,Ⅴ组作为对照。牵引成骨用自行设计制作的内置型钛镍合金牵张器 ,在牵张手术前及术后 1、5、13周拍X线片 ,分别在牵张完成后 1、3个月处死动物 ,进行组织学研究。结果　钛镍牵张器显示了良好的组织相容性 ,自动完成牵引骨形成 ,牵张器安置完成后骨块即开始移动 ,X线片可见牵张完成后 1个月牵张区骨密度增高 ,有新骨生成 ;3个月时新生骨密度与周围骨接近 ,有效地增加了牙槽嵴的高度和初步修复了下颌骨的节段性缺损。组织学观察可见牵张区新骨形成良好。结论　内置自加载钛镍记忆合金牵张器自动牵引成骨是一种具有良好应用前景的简便实用的牵引成骨技术。     

复方毛冬青注射液与3种输液配伍后的微粒及其pH值观察

目的　观察复方毛冬青注射液分别与 0 9%氯化钠注射液、10 %葡萄糖注射液和小儿用葡萄糖氯化钠注射液 3种输液配伍时的不溶性微粒及其pH值变化。方法　不同剂量 ( 4、6、8和 10ml)的复方毛冬青注射液分别与 10 0ml上述输液配伍 ,混合液的不溶性微粒利用微粒分析仪测定 ,以及其 pH值利用pH/离子计仪测定。 结果　不同剂量复方毛冬青注射液与各输液混合其 4个通道 (≥ 2 5 μm、≥ 10 μm、≥ 5 μm、≥ 2 μm)的不溶性微粒均显著性增多 (P <0 .0 1) ,且其pH也有明显变化。 结论　复方毛冬青注射液与 3种输液配伍的不溶性微粒不符合中国药典及英国药典的质量标准 ,应引起重视。建议在临床应用时可在其一次性输液器加装有效的终端滤器     

Respiratory exposure to diesel exhaust particles decreases the spleen IgM response to a T cell-dependent antigen in female B6C3F1 mice.

We investigated the systemic immunotoxic potential of respiratory exposure to diesel exhaust particles (DEP) in this study. Female B6C3F1 mice (approximately 8 weeks old) were exposed to increasing concentrations of DEP intratracheally, 3 times every two weeks, and sacrificed 2 or 4 weeks after the first exposure. The systemic toxicity and immune status in mice were evaluated. Mice exposed to DEP (1 to 15 mg/kg) showed no significant changes in body, spleen, or liver weights. Lung weights were increased in the mice exposed to 15 mg/kg DEP for 2 or 4 weeks. Except for a decreased platelet count, no significant alterations occurred in hematological parameters following DEP exposure. The number of splenic anti-sheep red blood cell (sRBC) IgM antibody-forming cells (AFC) decreased following DEP exposure for 2 weeks. This effect was less severe following 4 weeks of exposure and was only evident in the high dose group. Exposure to DEP also resulted in a significant decrease in the absolute numbers and the percentages of total spleen cells for total, CD4(+), and CD8(+) T cells, while the numbers of B cells and total nucleated cells in spleen were not significantly changed. The proliferative response of splenocytes to the T-cell mitogen, concanavalin A (ConA), as well as their production of IL-2 and IFN-gamma, was decreased dose-dependently following exposure of mice to DEP for 2 weeks, whereas proliferation was not changed in response to anti-CD3 monoclonal antibody. In summary, short-term respiratory exposure of mice to DEP resulted in systemic immunosuppression with evidence of T cell-mediated and possibly macrophage-mediated mechanisms.     

The effect of sandblasting treatment on endurance properties of titanium alloy hip prostheses

Sandblasting is a procedure of increasing surface roughness. This treatment is common in the orthopedic field. An increased roughness may affect the endurance limit of the material. This study investigates the effect on the endurance limit of the Ti6Al4V due to two different sandblasting treatments: fine sandblasting and coarse sandblasting. Twenty hip stems, 10 finely sandblasted and 10 coarsely sandblasted, were tested under sinusoidal fluctuating bending. The staircase method was used to estimate the endurance limit of the material. The results show an important reduction in the endurance properties up to 40% for the coarsely sandblasted specimens. The failures of the sandblasted specimens were not due to material defects. Rather, the decreased endurance strength of the sandblasted stems was caused by surface defects, which act as crack initiators. By modulating the roughness with an appropriate sandblasting treatment, it is possible to limit the reduction in the endurance limit of the alloy.     

超细颗粒沉降过程数值模拟

从单个颗粒运动轨迹出发,对存在团聚现象的颗粒沉降过程进行分析,建立了一个分析超细颗粒悬浮液沉降过程的数值模型,提出了加速沉降的促进函数ψ,推导出沉降效率数值模型.并用Matlab程序对钛白去离子水体系分离模型进行了计算模拟,得出钛白悬浮液沉降过程有3个阶段:微观力影响与宏观力影响近似平衡的开始阶段,微观力影响占主导的沉降加速阶段,和两者达到新平衡的沉降后期状态.并讨论了颗粒含量和粒径对沉降过程的影响:颗粒含量的降低或是粒径的增大都将使沉降加速阶段时间跨度增加.     

钛制空心钉结合张力带内固定手术治疗髌骨骨折

目的探讨膝关节直切口下空心拉力螺钉张力带钛丝内固定治疗髌骨骨折的优缺点及手术适应证.方法对27例髌骨骨折患者进行回顾性分析:横行骨折11例、粉碎骨折15例、陈旧性骨折1例均采用张力带钛丝结合2枚钛制空心拉力螺钉固定.结果所有患者随访3~20个月,骨折全部愈合,按胥少汀评分标准评估,优19例,良6例,可2例,优良率92%.结论采用钛制空心螺钉 张力带内固定技术治疗髌骨骨折固定牢固、疗效确切,适用于髌骨横行、粉碎性骨折.     

自制裸磁珠对常见食源性致病菌吸附性能的研究

目的：研究自制裸磁珠对常见食源性致病菌和卫生指示菌的吸附性能，摸索从样品中快速分离和浓集细菌的方法。方法：试验裸磁珠对细菌的吸附性能，摸索温度和样品成分对其吸附性能的影响。结果：自制裸磁珠在37℃对常见食源性致病菌和卫生指示菌有很强的吸附，吸附率均高于97％。食品成分对其吸附有一定影响，吸附率最低为58．42％。结论：自制裸磁珠可望用于环境和食品样品中多种细菌的非特异性吸附分离和浓集，值得进一步研究和推广。