A method for shape optimization of a hip prosthesis to maximize the fatigue life of the cement

The long term success of total joint replacement can be limited by fatigue failure of the acrylic cement and the resulting disruption of the bone-cement interface. The incidence of such problems may be diminished by reduction of the fatigue notch factor in the cement, so that stress concentrations are avoided and the fatigue crack initiation time maximized. This study describes a method for numerical shape optimization whereby the finite element method is used to determine an optimal shape for the femoral stem of a hip prosthesis in order to minimize the fatigue notch factor in the cement layer and at interfaces with the bone and stem.

A two-dimensional model of the proximal end of a femur fitted with a total hip prosthesis was used which was equivalent to a simplified three-dimensional axisymmetric model. Software was developed to calculate the fatigue notch factor in the cement along the cement/stem and cement/bone interfaces and in the proximal bone. The fatigue notch factor in the cement at the cement/stem interface was then minimized using the ANSYS finite element program while constraining the fatigue notch factor at the cement/bone interface at or below its initial level and maintaining levels of stress in the proximal bone to prevent stress shielding. The results were compared with those from other optimization studies.     

基于骨和无有机成分骨与羟基磷灰石压缩性能实验比较的强度分析

目的分析判定以珊瑚为基体,通过水热交换法制成的羟基磷灰石植入体内后的强度是否可以达到活体骨的水平。方法实验测量羟基磷灰石、含有机成分的骨、无有机成分的骨的压缩极限应力。通过对比羟基磷灰石、骨及无有机成分的骨的压缩强度差别,确定胶原纤维对骨压缩强度的作用,进而应用经验模型预估人造羟基磷灰石在一定空隙度(0.1～0.5)范围变化时的强度。结果羟基磷灰石、骨及无有机成分的压缩强度分别为14.1 GPa、207 GPa和31.7 GPa。结论去除骨中的有机成分后其压缩强度降低约80%。水热交换法制成的羟基磷灰石抗压强度可能高于骨内羟基磷灰石,这种骨替代材料植入体内后,随着骨和纤维组织在内部生长,其强度有可能达到活体骨的水平。     

血糖感应型胰岛素给药智能载体的研究进展

胰岛素控制释放高分子载体系统一直是国内外科技工作者的研究热点 ,迄今已经研究报道了多种具有不同工作原理的血糖感应型胰岛素给药智能载体。本文基于国内外大量研究文献 ,综述了血糖感应型胰岛素控制释放智能化高分子载体的研究进展。     

Dynamic mechanical thermal analysis of dental polymers: III. Heterocyelic methacrylates

Four heterocyclic methacrylates were investigated with respect to their loss tangent and activation energy using a dynamic mechanical thermal analyser over a limited frequency range of 0.033 to 90 Hz. The linear regression lines obtained showed an Arrhenius-type relationship between transition temperature and frequency. Their low activation energies in comparison to poly (methyl methacrylate) and bis-phenol A based methacrylates was thought to be a direct consequence of their low molecular weights.     

Decision and forecast horizons in a stochastic environment: A survey

This paper constructs a unified framework to survey most of the work done to date on decision

1 decision horizon replaces the term planning horizon used in the literature in the context of this paper. This is done because of an alternate and more popular use of the term planning horizon as simply the given length of the horizon in a finite horizon problem.

and forecast horizons in a stochastic environment. The paper is divided into sections by type of model. For each model type, the issues of existence of these horizons and of derivation of sufficient conditions for their determination are studied. Appropriate examples are presented.     

Using Metamodeling to Identify the Optimal Strategy for Colorectal Cancer Screening

ObjectivesMetamodeling can address computational challenges within decision-analytic modeling studies evaluating many strategies. This article illustrates the value of metamodeling for evaluating colorectal cancer screening strategies while accounting for colonoscopy capacity constraints.MethodsIn a traditional approach, the best screening strategy was identified from a limited subset of strategies evaluated with the validated Adenoma and Serrated pathway to Colorectal CAncer model. In a metamodeling approach, metamodels were fitted to this limited subset to evaluate all potentially plausible strategies and determine the best overall screening strategy. Approaches were compared based on the best screening strategy in life-years gained compared with no screening. Metamodel runtime and accuracy was assessed.ResultsThe metamodeling approach evaluated >40 000 strategies in <1 minute with high accuracy after 1 adaptive sampling step (mean absolute error: 0.0002 life-years) using 300 samples in total (generation time: 8 days). Findings indicated that health outcomes could be improved without requiring additional colonoscopy capacity. Obtaining similar insights using the traditional approach could require at least 1000 samples (generation time: 28 days). Suggested benefits from screening at ages <40 years require adequate validation of the underlying Adenoma and Serrated pathway to Colorectal CAncer model before making policy recommendations.ConclusionsMetamodeling allows rapid assessment of a vast set of strategies, which may lead to identification of more favorable strategies compared to a traditional approach. Nevertheless, metamodel validation and identifying extrapolation beyond the support of the original decision-analytic model are critical to the interpretation of results. The screening strategies identified with metamodeling support ongoing discussions on decreasing the starting age of colorectal cancer screening.     

2021年江苏省中药材生产统计分析

目的:对2021年江苏省中药材生产情况进行统计分析,为该省中药产业发展宏观管理和调控提供参考。方法:重点参考江苏省中药资源普查工作办公室、江苏省中药资源动态监测体系、国家中药材产业技术体系江苏相关岗站的实地调查数据,采用中药学、统计学与地理信息系统等领域的技术方法,对2021年江苏省全域中药材种植面积、品种,以及中药材产量、产值进行统计分析。结果:2021年,江苏省有68个县种植中药材,种植品种46种,种植面积共115.56万亩(1亩≈666.67 m^(2)),年产量54.06万t,年产值约69.38亿元。江苏省中药材种植面积及产量较大的地区主要分布在徐州市、盐城市、扬州市、南通市、泰州市和淮安市,占全省中药材种植总面积的97.72%。种植万亩以上的中药材有15种,种植面积达109.43万亩,占全省中药材种植面积的94.69%。本次统计中,江苏省乔木类中药材种植面积最大,种植面积为52.17万亩,占比45.14%;其次为草本类、藤本类、灌木类。江苏省重点中药材银杏、菊花、芡实、瓜蒌、黄蜀葵花和薄荷种植面积为40.97万亩,占全省中药材种植面积的37.44%;产量106336420 t,占全省中药材产量的19.66%。结论:本次统计结果反映了江苏省中药材的种植现状,为制定江苏省中药材生产及中药产业规划、调整农村中药材产业结构、建设中药材规范化种植基地提供科学依据,为促进中药资源信息化做出必要准备。     

聚—（羟丙基、丙基）—天冬酰胺材料体外酶解及植入小鼠体内的观察

目的：观察4种不同摩尔比的聚－（羟丙基、丙基）－天冬酰胺材料在体外酶解和植入小鼠体内后的变化。方法;用木瓜蛋白酶和胰酶对材料作了体外酶解试验,用凝胶色谱法对降解物碎片作了测定;用光镜、扫描电镜、透射电镜等对材料在埋植部位、肝、肾组织内的降解碎片进行观察;对材料植入小鼠体内后的生化指标（血红蛋白、白细胞、谷丙转氨酶、肌酐作了测定。结果：聚－（羟丙基、丙基）－天冬酰胺材料在体外能被逐步酶解。在植入小鼠体内的5周内,在埋植部位、肝、肾组织内能观察到材料的碎片。结论：聚－（羟丙基、丙基）－天冬酰胺材料能在体内、外逐步降解,植入小鼠体内后对动物的血象、肝、肾功能无明显的影响,具有生物相容性。     

化工过程在线模拟和优化的软件框架

首先讨论了在线优化和企业自动化水平的关系,接着描述了过程模型的开发和实现范例,并归纳了一个在线优化软件系统的功能需求,进而描述了一个面向程的模拟优化系统的主要组成部分,最后讨论了在线优化应用的结构以及和控制策略的关系。