Patient-Specific Contact Stress Does Not Predict Polyethylene Wear Rate in a Specific Pressfit Cup

Background

The most common reason for revision total hip arthroplasty remains polyethylene wear. Development dysplasia of the hip and revision situations requires a conscious compromise of implant position. The surgeon should know about the consequence on wear via a possible change in hip contact force. The objective of this study is to investigate whether annual wear is dependent on hip contact force.

粉煤气化工业装置煤粉黏附力表征及其流动性评价

气流床粉煤加压气化工艺中,煤粉颗粒粒径小、比表面积大,受颗粒间黏附力影响,煤粉在锁斗下料单元经常出现结拱架桥现象。本文以SE （Sinopec-ECUST）-东方炉气流床粉煤加压气化工艺为工业应用背景,以典型粒径特征的煤粉样品为研究对象,采用连续介质模型与颗粒间作用力分析相结合的方法,建模求解煤粉颗粒间的黏附力。通过对比不同样品的流动参数、颗粒间作用力及其与重力的相互关系,揭示了平均粒径及细颗粒含量对煤粉流动性和下料过程的影响,并在实验室可视化下料平台和工业装置下料单元对上述结果进行了验证。研究结果表明,随着平均粒径降低、细颗粒含量增加,煤粉流动性减弱,下料逐渐从结拱架桥过渡至无拱自由流。本文为改善入炉煤粉流动性、提高煤粉供料系统运行稳定性提供了有效的参考。     

数字化医院建设过程中的管理艺术

随着我国医药体制改革不断的深化和国内信息化产业的迅猛发展,近些年国内医院已经迈入"数字化医院"的建设阶段,本文从现代管理理论的角度出发,探讨医院组织文化与数字化医院建设管理水平的根本关系,并以此为基础,结合实践经验,阐述信息化建设过程中具体管理方法的运用。     

WISN方法在皮肤病专科医师配置中的应用

目的 使用WISN方法评估某专科医院皮肤病专科医师的人员需求及工作负荷情况.方法 选择某皮肤病专科医院8个开展皮肤病专科诊疗业务科室的临床医师为研究对象,利用WHO推荐的应用基于工作量指标的人力配置(WISN)方法进行人员配置及工作负荷评估.结果 根据该院2015年度承担的皮肤病专科诊疗服务(门诊、住院)和教学、科研任务需要的高、中、初级医师分别是46人、49人和37人,与医院实际在岗人员相比缺口分别为26人、24人和11人.高、中、初级医师的WISN比分别为0.4、0.5和0.7.结论 该院的皮肤病专科医师人力资源十分不足,临床服务任务较重,且各级人员的工作负荷呈现高级>中级>初级医师的现象.     

CAD/CAM钛合金表面处理工艺联合树脂粘接剂对硬质复合树脂粘接强度和耐久性的影响

目的:研究喷砂和微弧氧化两种金属表面处理方式及树脂粘结剂对钛合金与硬质复合树脂粘结强度和耐久性的影响。方法:应用CAD/CAM技术切削出80个底面直径10 mm、高8 mm的圆柱形钛合金试件。根据表面处理方式分为两组:喷砂组(sandblasting,SB)试件表面进行Al₂O₃ 颗粒喷砂,微弧氧化组(microarc-oxidation,MAO)试件表面处理后形成疏松多孔的陶瓷膜结构。每组内根据是否应用树脂粘结剂分为SB-resin luting-N组(不使用)、SB-resin luting-Y组(使用)、MAO-resin luting-N组(不使用)、MAO-resin luting-Y组(使用)4个亚组。试件与Cemerage硬质复合树脂粘结固化,每组的各一半测试冷热循环0次和5 000次后的粘结强度,对比分析测试结果。扫描电镜观察粘结强度试验前后钛合金试件表面形貌。结果:喷砂联合树脂粘结剂组冷热循环0次后,钛合金与硬质复合树脂的粘结强度最高(16.2±1.8) MPa;微弧氧化未联合树脂粘结剂组冷热循环5 000次后,两者的粘结强度最低(8.9±1.5) MPa,喷砂和微弧氧化未联合树脂粘结剂组冷热循环5 000次后粘结强度分别为(10.7±2.2) MPa和(8.9±1.5) MPa,相比循环0次组降低,差异有统计学意义(P=0.000和P=0.001);喷砂和微弧氧化处理联合树脂粘结剂5 000次冷热循环后粘结强度分别为(15.5±2.1) MPa和(11.7±1.3) MPa,相比循环0次组降低,但差异无统计学意义(P=0.087和P=0.234)。结论:喷砂和微弧氧化两种表面处理方式联合树脂粘结剂均可提高钛合金与硬质复合树脂的粘结强度和耐久性,以喷砂组提高更为显著;目前受微弧氧化技术参数的限制,喷砂效果优于微弧氧化。     

乳腺浸润性癌声脉冲辐射力成像特征分析

目的 探讨乳腺浸润性癌的声脉冲辐射力成像的特征.方法 回顾性分析40例乳腺浸润性癌患者共计42个病灶的声触诊组织定性成像(VTI)和声触诊组织定量成像(VTQ)上的特征.结果 42个乳腺浸润性癌病灶VTQ检测,横向剪切波速度(SWV)范围为1.34 ～9.00 m/s,平均(6.28±2.95) m/s,相同深度处周围乳腺组织SWV范围为0.93～2.11 m/s,平均(1.29±0.24)m/s,两者差异有统计学意义(t=10.93,P=0.00).乳腺浸润性癌与相同深度周邻乳腺组织的SWV的比值范围为0.95 ～9.68,平均(4.98±2.54).乳腺浸润性癌病灶VTI分级共6级,其中1级0个、2级3个、3级5个、4级17个、5级15个、6级2个.VTI图像分级4～6级占80.95％ (34/42).结论 VTQ和VTI能定量及定性的反映乳腺浸润性癌病灶的硬度,对乳腺浸润性癌的诊断可以提供数据参考.     

Computational Dehydration of Crystalline Hydrates Using Molecular Dynamics Simulations

Molecular dynamics (MD) simulations have evolved to an increasingly reliable and accessible technique and are today implemented in many areas of biomedical sciences. We present a generally applicable method to study dehydration of hydrates based on MD simulations and apply this approach to the dehydration of ampicillin trihydrate. The crystallographic unit cell of the trihydrate is used to construct the simulation cell containing 216 ampicillin and 648 water molecules. This system is dehydrated by removing water molecules during a 2200 ps simulation, and depending on the computational dehydration rate, different dehydrated structures were observed. Removing all water molecules immediately and removing water relatively fast (10 water molecules/10 ps) resulted in an amorphous system, whereas relatively slow computational dehydration (3 water molecules/10 ps) resulted in a crystalline anhydrate. The structural changes could be followed in real time, and in addition, an intermediate amorphous phase was identified. The computationally identified dehydrated structure (anhydrate) was slightly different from the experimentally known anhydrate structure suggesting that the simulated computational structure could represent a kinetically trapped dehydration intermediate.     

总义齿咬合平面定位对最大咬合力的影响

为观察总义齿咬合平面定位设计与患者咀嚼功能的关系，选择１０名无牙颌患者，分别为每个患者各作４副总义齿，其中有一副义齿（标准义齿）的咬合平面以上中切牙近中切角为基准或向后上、或向后下、或向左右方向倾斜５°。测定患者戴各义齿用单侧尽最大力咬合时的力值，发现患者戴标准义齿时平均最大咬合力值显著高于其它义齿。该结果提示：总义齿的咬合平面平分颌间距离且与耳屏鼻翼线平行最有利于无牙颌患者咀嚼功能的发挥     

Voltammetry and surface analysis of AISI 316 stainless steel in chloride-containing simulated concrete pore environment

The study of passive layers grown on AISI 316 stainless steel in solutions that simulate concrete pore environments contaminated with Cl^? is presented. Model solutions of saturated Ca(OH)₂ and cement extract (CE) with and without the addition of 5 g/L of NaCl are compared. Cyclic voltammetry (CV) shows different electrochemical responses of passive layers grown on samples immersed in these solutions under open circuit potential (ocp). A more resistive passive film was found on the samples exposed to the CE solution. The different voltammetric responses suggest differences in composition of the passive layers formed on each solution. XPS spectra confirm the dissimilarity in atomic composition. Optical microscope images and AFM images of the pits formed on the samples illustrate the differences of AISI 316 surface topography after exposure to model solutions. Because of these differences, it is recommended to use CE solution as a model solution and ocp passivation to simulate concrete environments.     

树脂加强型玻璃离子黏结剂黏结力的实验研究

目的 了解光固化树脂加强型玻璃离子水门汀的剪切强度能否满足临床需要;并比较不同条件下其剪切强度的变化.方法 收集离体前磨牙50颗,随机均分为5组.第1组(对照组):35%磷酸酸蚀30s,冲洗、干燥,涂黏结剂,采用京津釉质黏结剂黏结托槽.第2、4组:35%磷酸酸蚀30s,冲洗,湿润,采用光固化型的Fuji Ortho Lc树脂加强型玻璃离子黏结托槽.第3、5组:不酸蚀,采用光固化型的Fuji Ortho Lc树脂加强型玻璃离子黏结托槽.1、2、3组用电子万能实验机测24h的抗剪切强度,4、5组测30 min的抗剪切强度.并统计牙面上的黏结剂残留量.结果 第2、3、4组的抗剪切强度均能满足临床需要,第5组的抗剪切强度不能满足临床需要,第2组的抗剪切强度与其它各组相比差别有显著性.结论 光固化树脂加强型玻璃离子在酸蚀和免酸蚀后24h,以及酸蚀黏结30min后的剪切强度均能满足临床需要;而免酸蚀黏结30min的抗剪切强度不能满足临床需要;酸蚀后光固化树脂加强型玻璃离子的剪切强度明显增强.