Fontan术血流动力学非牛顿特性研究

目的 分析计算模拟中血液非牛顿特性对Fontan术后血流动力学的影响.方法 基于Fontan术后患者个体化三维血管模型,临床超声实测数据作为边界条件,分别选取常用的牛顿流体模型、非牛顿流体模型中的Casson模型与Carreau模型进行血流动力学模拟,计算血流分配比、能量损失、壁面切应力、非牛顿重要性系数等血流动力学参...     

溶质在作圆管层流的牛顿—Casson两层流体中的分散及外围层效应

本文考察溶质在作圆管层流的牛顿－Ｃａｓｓｏｎ两层流体中的分散规律，同时考察了外围层效应和屈服应力效应，利用Ｔａｙｌｏｒ简化假定，在一定边界条件下，导出相对浓度分布和等效扩散系数的解析式，作出相应讨论，分析和计算了外围层诸因素ε以及Ｃａｓｓｏｎ流体屈服应力ｆｃ对分散影响的效应。单层Ｃａｓｓｏｎ流体和两层牛顿流体中的分散可视可为本文的特殊情形。     

肝脏血供的血流动力学模型研究

基于血流网络模型理论所建立了肝脏血供的血流动力学数学模型,可用于对人体正常或患病肝脏特殊的双重血供问题进行模拟分析研究.基于临床测试数据,应用系统辨识方法确定肝脏血流模型参数,并针对肝硬化、肝癌的血流异常变化进行血流动力学分析,表明模型能够较好地模拟的肝脏血流变化状况.     

血管内介入治疗中的血流动力学问题

本文结合作者等人的工作，从血流动力学的角度对血管内介入治疗进行了综述。论述了神经系统血管病介入治疗、动脉瘤介入治疗、肝癌介入治疗和肺癌介入治疗等临床上存在的急切需要解决的血流动力学问题。其中，还着重介绍了作者等人在肺癌介入治疗的血流动力学问题上的研究成果。这些研究成果为解决肺癌介入治疗临床上严重存在的“高位截瘫”并发症问题提供了一个有效的原理和方法。     

正常体位下人体椎动脉内血流动力学数值模拟分析

目的:保证研究对象的椎动脉在正常体位下,即保证研究对象没有向前或向后发生椎动脉过度拉伸或弯曲的情况下,采集临床CTA图像,应用三维重构方法构建体外人体真实椎动脉并应用计算流体力学方法进行血流动力学数值模拟,比较不同研究对象椎动脉的血流动力学参数,分析椎动脉狭窄与血流动力学的关系。方法:研究对象A椎动脉在基底动脉之前部分出现狭窄;研究对象B椎动脉正常。采集的临床CTA图像均为Dicom格式,层间距为0.5 mm,每片图像的平面分辨率为512×512,像素大小为0.5 mm。应用医学图像后处理软件Simpleware对CTA二维医学图像据进行处理得到人体椎动脉三维立体模型。将椎动脉三维立体模型导入到CFD软件中进行前处理、网格划分和数值模拟。结果:通过瞬态模拟计算,得到了椎动脉在心动周期内不同时刻的血流动力学参数。结论:通过对比两个不同个体的血流动力学参数来分析椎动脉内血流动力学参数与椎动脉狭窄的关系,发现椎动脉狭窄血流动力学因素(如低流速、低壁面切应力、高振荡壁面切应力)可以诱发和加速与动脉粥样硬化及血栓的形成,为进一步研究椎动脉狭窄等疾病的发病机理提供理论支持。     

眼外伤的眼底血流动力学研究

目的研究眼外伤的眼底血流动力学变化。方法应用彩色多普勒显像检测６２只正常眼和 ９２只眼外伤患者的视网膜中央动脉（ＣＲＡ）、睫状后短动脉（ＳＰＣＡ）的血流参数,测定收缩期流速（ＰＳＶ）、舒张期流速（ＥＤＶ）、搏动指数（ＰＩ）、阻力指数（ＲＩ）。结果眼外伤组的 ＣＲＡ的 ＰＳＶ、ＲＩ均低于正常组（Ｐ＜０．０１）、ＣＲＡ的 ＥＤＶ、ＰＩ及 ＳＰＣＡ的 ＰＳＶ、ＥＤＶ、ＰＩ、ＲＩ两组比较均未见明显差异。结论眼外伤组ＣＲＡ血供降低是引起视功能障碍的重要原因之一,给临床对眼外伤的诊治和预后提供重要的依据。     

脑梗死早期血流动力学模型的研究

脑梗死发病早期,血管闭塞直接造成了脑血流动力学的变化.为定量研究梗死发生后缺血脑组织残余血流变化和多种变量间的关系,本文使用血流动力学的相关原理,依据脑血流自动调节机制,在理论上建立影响残余血流的数学模型,并结合临床对该模型进行讨论和研究.     

平行平板流动腔中Casson流体脉动流的摄动解

高度远小于横向和纵向几何尺寸的矩形平行平板流动腔是人们用以体外研究细胞在切应力作用下力学行为的主要工具之一，考虑到通常采用的矩形平行平板流动腔内的流动属于小雷诺数流动，本文用雷诺数作为摄动参数求出了矩形平行流动腔内Casson流体脉动流的摄动解，给出了腔内切应力随压力梯度和流量的变化规律。数值结果表明，相同压力梯度下Casson流体和牛顿流体对应的腔内切应力分布无明显不同，而在相同流量条件下，Casson流体和牛顿流体对应的腔内切应力分布有明显差异，本文为Casson流体脉动流条件下平行平板流动腔切应力的确定方法提供了理论依据。     

脑梗死早期血流动力学模型的研究

脑梗死发病早期，血管闭塞直接造成了脑血流动力学的变化．为定量研究梗死发生后缺血脑组织残余血流变化和多种变量间的关系，本文使用血流动力学的相关原理，依据脑血流自动调节机制，在理论上建立影响残余血流的数学模型，并结合临床对该模型进行讨论和研究．     

疾病情况下肾小球血流动力学

肾小球滤过是一个受许多生理学因素调节的复杂过程。临床许多疾病中常见有肾小球滤过率(GFR)的变化。后者可由于肾小球结构的损害,也可由于或伴有肾小球血流动力学的影响。本文简述在生理和病理情况下肾小球血流动力学的调节机制和特征。     

Determining blood cell size using microfluidic hydrodynamics

Microfluidic flow cytometers currently analyze far fewer parameters than conventional flow cytometry or fluorescence activated cell sorting (FACS) in order to minimize cost and complexity. There is a need for microfluidic devices that analyze more and or new cell parameters with compact and minimal means. Here we show a new and explicitly microfluidic parameter, "hydrodynamic" cell size, and compare it to forward scatter in conventional flow cytometry. The hydrodynamic size of cells is determined by the degree of lateral displacement experienced while traveling through a 1.2-mm-wide non-clogging array of micro-fabricated obstacles. We show comparable size resolution between the microfluidic device and forward scatter in conventional flow cytometry and without the need to lyse red blood cells. We use the device to differentiate healthy lymphocytes from malignant lymphocytes by size alone and we use the device to detect increased numbers of activated lymphocytes in blood as a result of exposure to staphylococcal enterotoxin B (SEB), a potential bioterror agent. Together the results demonstrate a microfluidic device that performs some of the measurement and separation tasks of a flow cytometer but at a potentially lower cost and complexity.     

Effects of NMDA and calcium channel antagonists on regional cerebral blood flow.

N-Methyl-D-aspartate (NMDA) antagonists and voltage-dependent calcium channel antagonists were tested to determine potential effects on regional cerebral blood flow in the normal rabbit brain. Ketamine had no effects on cortical or hippocampal blood flow, but was found to significantly decrease blood flow in the inferior colliculus. MK-801 decreased blood flow in almost all regions of the brain tested. On the other hand, nimodipine significantly increased flow in the cortex, hippocampus, and tegmentum. Dextromethorphan and dextrorphan, which have been shown to act at the NMDA receptor as well as the dihydropyridine calcium channel, decreased blood flow in the inferior colliculus, but showed no effects in the cortex or hippocampus. These results suggest that the neuroprotective NMDA antagonists do not increase blood flow primarily in the normal brain.     

复杂动脉血管内血液流动的研究进展

动脉硬化是一种严重影响人类健康的动脉血管常见病。大量的研究证明动脉硬化病灶的产生与动脉管壁的切应力分布有着密切的联系，其易友部位位于腹主动脉末端、冠状动脉、颈动脉分又等处。本文就动脉硬化的易发部位出发，对复杂动脉血管内血液流动的近期研究作一综述。     

血液流体动力学研究与生物反应器在组织工程血管构建的应用

利用生物反应器构建组织工程化血管是近年来诞生的一项新技术。本文综述了其理论基础即血液流体动力学的研究进展,生物反应器的原理、结构、应用及评估,同时提出存在的问题并展望其应用前景。     

The rate of blood flow in experimental bubonic plague

Summary The circulation rate was studied during experimental plague in guinea pigs and rabbits by means of the isotope method. In guinea pigs with a rapid course of plague infection, with the animals' death occurring on the 4th–5th day, the circulation rate decreases 1–2 days after the infection. With a more torpid infectious process the circulation rate showed some rise during the initial period. Beginning from the 3rd–4th day after the infection in all the guinea pigs there was seen a 11/2–2 reduction of the circulation rate in comparison with the initial one. In rabbits suffering from typical plague with characteristic pathologico-anatomical changes and bacteriological isolation ofBacillus pestis from the organs, the circulation rate during the infectious process is almost halved in comparison with its initial value.(Presented by Active Member of the Akad. Med. Nauk SSSR N. N. Zhukov-Verezhnikov) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 53, No. 2, pp. 47–52, February, 1962     

急性缺血心肌的血流量再分布

利用放射性生物微球技术,研究了犬在急性心肌缺血时,侧支循环血流量的再分布,在结扎左前降支冠脉后,中心缺血区血流量明显减少。近边缘区血流量大于中心缺血区血流量,小于远边缘区和非缺血区的血流量。中心缺血区和近边缘区的心内膜下层心肌血流量低于心外膜下层心肌血流量,两者之比小于1.00。随着缺血时间的延长(1—6小时),中心缺血区血流量逐渐减小,而非缺血区的血流量逐渐增加。     

Colour Doppler flow mapping: providing an insight into cardiac hydrodynamics

Colour Doppler flow mapping can now provide spatial velocity information in relation to surrounding structural detail as imaged by conventional echocardiography and, as such, represents a major advance in non-invasive cardiac imaging. This article describes the basic principles of colour Doppler flow mapping, details how the Doppler information is processed and displayed to arrive at the real-time two-dimensional flow-enhanced image. Since colour Doppler flow mapping is really the first available technique which allows detailed real-time velocity information to be displayed in vivo and in relation to intracardiac structures, it can allow important insight into the haemodynamics of intracardiac flow. With the application of digital computer analysis techniques it may also be possible to extract valuable quantitative information from colour Doppler flow mapping.