绵羊双叶人工心脏瓣膜替换的实验配合与体会

风湿性心脏瓣膜病在我国仍是危害人民健康的常见病,据不完全统计,患病人数达220万左右,目前我国每年进行瓣膜替换手术大约4000例c双叶瓣的设计、生产、研制、动物实验及临床应用在国外已有门年以上的历史,但我国仍属空白。由航天部703所高级工程师张大幕在借鉴国外双叶瓣膜和国内GK型人工心瓣的基础上,设计制做了新型全碳双叶人工心脏瓣膜。我院心脏外科成功地将此瓣膜在绵羊。已脏三尖瓣进行了替换。该实验为我国自行设计制造双o－f。机械人工心脏瓣膜及将其应用临床翻开了新的一页。我们医学实验动物中心在术前准备,术中配合及术后…     

图像数值分析在人工机械心脏瓣膜运动特征中的应用

动态图像测量技术是一种非接触式、动态、精确的检测运动物体特性的分析方式。人工心脏瓣膜体外动态开闭性能测试,依靠高速图像摄影技术捕捉瓣膜的细微运动,快速图像和精准的时间记录,将瓣膜运动转化为图像信息,分析瓣膜及各组件运动时的相对位移和速度变化,有效地解析瓣膜运动状况,为评价瓣膜性能提供参考。在人工心脏瓣膜脉动流平台上,选择双叶型机械心脏瓣膜在正常心动条件下,采用高速摄影技术通过标记点跟踪瓣膜瓣叶运动,记录瓣膜的运动轨迹及运动状态;通过图像数值分析瓣膜开启和关闭的运动情况,将瓣膜运动过程离散为多步静止状态的图像,离散后的图像数据导入Matlab数值分析,解析瓣膜中瓣叶的转动速度及角加速度等运动状态。以此改善瓣膜结构与流场之间的相互作用,改进瓣膜使用性能,结合瓣膜临床病症特征,解决瓣膜类相关并发症。     

基于ANSYS Workbench刚度分析的人工心脏瓣膜设计

利用ANSYS Workbench软件对St.Jude瓣膜和与St.Jude瓣膜结构相同的钛合金瓣膜进行刚度分析,根据结果优化钛合金瓣膜结构。通过计算机辅助工程对优化后的双叶机械心脏瓣膜进行装配模拟分析,得到瓣膜变形的应力应变情况。瓣环的最大应力未超过材料的屈服强度,利用三维坐标测量仪对装配前后进行检测,结果表明:根据模拟的最小变形可以进行装配,装配后的瓣环未发生塑性变形。     

基于注塑过程数据的制品尺寸合格性判定

针对注塑生产过程中人工质量检测存在的效率低、成本高等问题,提出了一种基于注塑加工过程数据对产品尺寸是否合格进行预测判定的方法,首先对于清洗后的数据集采用5折交叉验证筛选出LR模型、SVM模型等5个分类模型,然后以ROC曲线和AUC值作为性能评估指标,综合比较和分析了5个分类模型在不同特征选取方法下的分类性能。结果表明:基于树模型特征选取与LR算法组合对本文的数据集表现出优良的分类性能,准确率可达96.42%,具有一定的工程应用价值。     

纤维基组织工程心脏瓣膜支架研究进展

心脏瓣膜损坏或缺陷所导致的疾病已成为危害人类健康的主要疾病之一.由纤维材料成型技术制备的组织工程支架具有良好的可设计性和较好的力学和生物性能,逐渐成为组织工程心脏瓣膜支架的主要制备方法.全文重点介绍了纤维基组织工程心脏瓣膜支架的研究进展,对采用针织、非织造以及静电纺丝制备技术得到的微纳米纤维基支架的各自特点进行了对比分析,由此表明具有优良生物相容性和可控力学性能的三维多孔纳米纤维基支架将是组织工程心脏瓣膜支架的发展方向.     

人工心脏瓣膜的研究进展

归纳总结了生物瓣和机械瓣的优点与缺点,综合论述了组织工程心脏瓣膜和机械瓣的研究发展方向.重点探讨了薄膜血液相容性的机理和利用类金刚石薄膜来提高机械瓣膜血液相容性的研究,为人工心脏瓣膜的研究、开发和临床应用提供一个参考.     

原花青素在酸性条件下交联制备心脏瓣膜的性能研究

为了明确原花青素(procyanidins,PC)在酸性条件下交联脱细胞心脏瓣膜是否能够维持其柔顺度、抑制其钙化成核和具备良好的生物学特性,以1 mg/mL PC在酸性条件下(pH3.0~7.4)交联脱细胞心脏瓣膜,采用万能力学测试仪测试研究其柔顺度,并用体外钙化、体外酶降解、细胞黏附、抗凝血和血小板黏附实验研究其抗钙化和相关生物学特性.结果显示,弱酸性条件下交联的脱细胞瓣膜(PC1-pH6.0)呈现出近似于未交联脱细胞瓣膜的柔软程度,交联后拉伸强度显著提高(5.95±0.6)MPa vs(4.64±0.81)MPa,同时弹性模量与未交联对照组相当,显示出较好的柔顺度;PC1-pH6.0组体外可有效抑制瓣膜钙化;PC交联能保护脱细胞瓣膜不被II型胶原酶降解,瓣膜间质细胞在交联脱细胞瓣膜表面黏附良好,交联后的脱细胞瓣膜具有更好的抗血栓潜能.因此,pH6.0条件下PC交联的脱细胞心脏瓣膜具有类似于未交联脱细胞瓣膜的柔顺性,能有效抑制钙化,具有抗酶降解、抗血栓和良好的细胞相容性,有望用作可再细胞化的生物瓣.     

两种体外预应力混凝土梁弯曲性能之比较分析

对整体式与节段式体外预应力混凝土梁的弯曲性能进行了比较分析.应用研发的体外预应力结构非线性有限元专用程序,对整体施工的体外预应力混凝土梁和节段施工的体外预应力混凝土梁分别改变其普通钢筋配筋率、体外索初始张拉力、体外索布筋形式和节段数目,进行从预应力张拉到加载破坏的全过程仿真分析,得到相应的荷载-挠度曲线及相关数据,比较了整体式体外预应力梁与节段式体外预应力梁在弯曲性能上的表现异同,对其原因进行了分析,得出相关结论.     

基于带孔U-net神经网络的肺癌危及器官并行分割方法

为了提高肺癌放疗计划危及器官勾画的精度和效率,提出了一种基于带孔U-net神经网络的肺癌放疗计划危及器官肺及心脏的并行分割方法.首先,构建了肺窗、心脏窗以及纵膈窗下的三通道伪彩色图像数据集,将图像数据集分成训练集、验证集以及测试集;然后,搭建了带孔U-net神经网络,利用训练集和验证集对其进行训练和参数调优;最后,利用测试集对训练后的带孔U-net神经网络进行图像分割性能评价,并与U-net神经网络及3种传统图像分割算法进行比较.实验结果表明,带孔U-net神经网络分割性能最优,可有效地完成肺及心脏的自动并行分割,提高勾画效率,分割结果与人工勾画结果相当.     

水泵性能检测试验数据处理及软件设计

水泵性能检测是保障水泵市场产品质量的重要手段,本文介绍了用最小二乘法对水泵性能检测试验数据进行拟合,以达到对水泵运行工况和性能进行分析的目的。基于VB编程,设计开发了水泵性能曲线绘制和分析软件,具有水泵性能曲线动态绘制、打印输出和自动纠错等功能,大大提高了水泵性能试验数据分析处理效率。最后通过实际算例对软件进行了应用分析。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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