酸性磷酸酶在大鼠脉络丛上皮细胞内的亚细胞定位

研究大鼠脑室脉络丛上皮细胞内酸性磷酸酶(Acid phosphatase,AcPase)的超微结构分布.取成年SD大鼠侧脑室、第三脑室和第四脑室的脉络丛组织,按硝酸铅法进行酸性磷酸酶电镜酶细胞化学染色显示.透射电镜下ACPase阳性反应物仅见于脉络丛上皮细胞内的初级和次级溶酶体上.通过延长孵育时间和改变固定条件(戊二醛浓度为0.5%)在脉络丛上皮细胞内的高尔基复合体扁囊和囊泡中也观察到了ACPase阳性反应物.各脑室脉络丛上皮细胞酸性磷酸酶的分布未见明显差异.文中讨论了脉络丛上皮细胞内ACPase的分布特征及其功能.     

大鼠侧脑室及其脉络丛室管膜上皮的超微结构观察

采用扫描和透射电子显微镜研究大鼠侧脑室及其脉络丛室管膜上皮的超微结构特征，并探讨其功能。扫描电镜观察结果：侧脑室壁室管膜上皮细胞游离端呈不规则多边形，可见纤毛及微绒毛，偶见分泌泡，脉络丛上皮细胞游离端微绒毛及分泌泡丰富，纤毛光见，可见、丛上细胞”。透射电镜观察发现，侧脑室壁及脉络丛上皮均由单层立方上皮组成，但二类上皮细胞的超微结构明显有别，室管膜上皮表面可见纤毛及微绒毛，分泌泡少见，脉络丛上皮游离端微绒毛丰富，常吻合成迷路样网，微绒毛的顶端膨大，形成微顶浆分泌小泡，胞浆内细胞器丰富，大鼠侧脑室壁及脉络丛上皮超微结构的差异反映二者功能的不同，本研究认为侧脑室脑脊液分泌的主要部位是脉络丛，其分泌的方式除脉络丛上皮细胞的主动运输功能外，可能微顶浆分泌法是侧脑室脑脊液形成的主要方式。     

Image stabilization and registration for tracking cells in the microvasculature

We propose a registration system to be used for tracking cells in intravital video microscopy that 1) stabilizes jitter-the undesired translational displacement of frames due to respiratory movement, etc., and 2) registers frames in a moving field of view (FOV) to allow for cell tracking over an extended range. For the first time, tracking of rolling leukocytes in vivo over a moving FOV is demonstrated. In a fixed FOV, stable background regions are located using a morphological approach. Template subregions are then selected from the stable regions and matched to corresponding locations in a reference frame. We show the effectiveness of the stabilization algorithm by using an active contour to track 15 leukocytes previously untrackable due to jitter. For 30 fixed FOV sequences containing rolling leukocytes, the resulting root-mean-square error (RMSE) is less than 0.5 microm. To align frames in a moving FOV, we present a modified correlation approach to estimate the common region between two consecutive fixed FOVs. We correlate the overlapping regions of the initial frame of the current fixed FOV and the final frame of the previous fixed FOV to register the images in the adjoining moving FOV. The RMSE of our moving FOV registration technique was less than 0.6 mmicrom. In 10 sequences from different venules, we were able to track 11 cells using an active contour approach over moving FOVs.     

Membranous body in the jejunal absorptive cells of suckling rat intestine

In the jejunal absorptive cells of suckling rats, a distinctive membranous body was found in their lateral cytoplasm and the Golgi region. This organelle was ovoid in contour (1 to 2 microns in diameter) and consisted of highly convoluted cisternae of a rough endoplasmic reticulum (RER). The individual cisternae were round (approximately 55 nm in diameter) with variable electron-dense content and separated by uniformly narrow channels (approximately 25 nm in width) which were continuous to the cytoplasmic matrix. In a proper section, the cisternae arranged in an approximately hexagonal pattern, and one of the cisternae was seen occupying the center of the hexagon. The membranous body was in continuity at its margin with the cisternae of a smooth endoplasmic reticulum (SER), and with the dilated cisternae which often contain chylomicron lipid droplets. It is possible that this structure serves as a kind of "reservoir" of the SER membranes for the lipid synthesis of the jejunal absorptive cells.     

Confocal laser speckle autocorrelation imaging of dynamic flow in microvasculature

Laser speckle imaging has been widely used for in-vivo visualization of blood perfusion in biological tissues.However,existing laser speckle imaging techniques suffer from limited quantification accuracy and spatial resolution.Here we re-port a novel design and implementation of a powerful laser speckle imaging platform to solve the two critical limitations.The core technique of our platform is a combination of line scan confocal microscopy with laser speckle autocorrelation imaging,which is termed Line Scan Laser Speckle Autocorrelation Imaging(LS-LSAI).The technical advantages of LS-LSAI include high spatial resolution(~4.4μm)for visualizing and quantifying blood flow in microvessels,as well as video-rate imaging speed for tracing dynamic flow.     

Difficulties in the Further Development of Venous Hemodynamics

The validity of hemodynamic theories developed for the arterial tree is examined with respect to their applicability to the venous system. The Navier-Stokes and continuity equations are given and the assumptions (in terms of these equations) found useful and justifiable for arterial theories are briefly described. The validity of these assumptions with respect to the venous system is considered. The significance of the dissimilarities in terms of computer simulation (analog and digital) is discussed. It is concluded that in regions which do not collapse much of the theory developed for the arterial system is applicable; in those regions which do collapse, theories based on the nonlinear Navier-Stokes equation should be considered.     

Computer Simulation Studies of the Venous Circulation

An analog computer model of the human cardiovascular system has been set up in which detailed attention is given to the representation of pressure and flow events in the veins, including effects of gravity, collapse, breathing, and the action of venous valves. This model, which includes a control loop for heart rate, was checked against human venous pressure waveforms and against response of the human to tilt-table experiments. These comparisons indicate that the model is valid for the study of postulated venous tone control characteristics; it should also be useful in the study of the mechanisms of venous return and circulatory system response during unusual acceleration conditions.     

The lamina suprachoroidocapillaris of the guinea pig choroid confirmed by the rapid freezing and freeze-substitution method

There is a compact layer (the lamina suprachoroidocapillaris) between the vascular and the choroidocapillaris layer of the guinea pig and rat choroids. The specimens were treated with the rapid freezing and freeze-substitution method. The choroidal melanocytes and their processes were exclusively built up of several layers, and the arterioles and venules passed through this layer. Numerous nerve terminals were seen throughout this layer, which contained small or large-size synaptic vesicles with dense or light core. These results may facilitate further understanding of the microcirculation in the choroidal architecture.     

Measurement of Respiration Rate from Central Venous Pressure in the Critically Ill Patient

Central venous pressure is measured in critically ill patients. The venous pressure is transmitted to a strain gauge transducer through a catheter inserted into the right atrium or superior vena cava. Through a signal conditioning technique using a low-pass filter with a cutoff at 0.8 c/s, the pulsatile variations related to heart action that are superimposed on the low-frequency respiratory changes are removed. The output of the respirometer is sampled every five minutes by art IBM 1710 control system computer and printed on an output typewriter, together with a number of variables, in a comprehensive patient monitoring system.     

松果体脑砂与胶原纤维关系的SEM观察和能谱化学元素分析

松果体为脑内重要的神经内分泌器官。松果体的主细胞———松果体细胞 (ｐｉｎｅａｌｏｃｙｔｅ) ,通过交感神经通路接受光 -暗时间信号的调控 ,合成并释放单胺 (ｍｏｎｏａｍｉｎｅ)和多肽 (ｐｏｌｙｐｅｐｔｉｄｅ)类激素物质 ,与机体的生长、发育、成熟、衰老等生命进程密切相关。人松果体内出现的钙化或矿化砂斑被称为脑砂 (ｂｒａｉｎｓａｎｄ) ,被临床医学用作Ｘ ｒａｙ颅脑结构的定位标志。然而 ,关于松果体脑砂的形成机制及其存在的机能意义 ,目前仍不十分清楚。我们应用ＮａＯＨ化学消蚀法制备人松果体胶原纤维组织支架和脑砂 ,并…     

Admittance and radiation efficiency of the human body in the resonance region

By using the body as a monopole antenna the admittance and radiation efficiency have been measured in the frequency range 30-70 MHz. It is concluded that there are no resonance effects. The efficiency is about -2 dB at the higher frequencies.     

Invasion of the body scanners

A key to accurate body scanning is the ability to digitize the body in three dimensions. Digital three-dimensional representations of real objects or models have been used for computer-generated special effects in movies. Where manual generation of such a model is very time consuming and expensive, it is possible to obtain an accurate three-dimensional representation of an object, even the human body, using optical scanning methods. Optical scanning has many advantages in that it is accurate, noncontact, and extremely rapid. It can be combined with color cameras to obtain a full-color, three-dimensional digital image, and an entire body can be scanned in less than 20 seconds     

Anatomy and flow in normal and ischemic microvasculature based on a novel temporal fractal dimension analysis algorithm using contrast enhanced ultrasound

Strategies for improvement of blood flow by promoting new vessel growth in ischemic tissue are being developed. Recently, contrast-enhanced ultrasound (CEU) imaging has been used to assess tissue perfusion in models of ischemia-related angiogenesis, growth-factor mediated angiogenesis, and tumor angiogenesis. In these studies, microvascular flow is measured in order to assess the total impact of adaptations at different vascular levels. High-resolution methods for imaging larger vessels have been developed in order to derive "angiograms" of arteries, veins, and medium to large microvessels. We describe a novel method of vascular bed (microvessel and arterial) characterization of vessel anatomy and flow simultaneously, using serial measurement of the fractal dimension (FD) of a temporal sequence of CEU images. This method is proposed as an experimental methodology to distinguish ischemic from nonischemic tissue. Moreover, an improved approach for extracting the FD unique to this application is introduced.     

LIN总线在车身控制中的应用性研究

LIN总线简介LIN总线主要用于汽车电子控制系统,构成CAN、TTP/C等高速总线的辅助网络,实现汽车网络的分级制结构,以简化线束,合理利用网络资源,节约成本。     

仿真技术在车身修复中的应用

现在的修复技术在修复过程中,可能造成二次伤害,没有理论力学的分析和支持。容易造成二次伤害,如果利用仿真软件进行分析,可以避免二次伤害的形成,同时为修复提供理论依据参考。利用Solidworks软件进行仿真分析,为车身修复提供理论支撑。     

Noise contribution of the body resistance in partially-depleted SOIMOSFETs

An additional noise component is observed in the noise spectrum of transistors in a partially-depleted (PD) medium-thickness SOI-CMOS technology. We identify the origin of this additional noise in the noisy resistance of the body film. This resistance, coupled to the gate capacitance, forms an RC filter and generates the hump-shape of the additional noise component. Several experimental observations that support this model are presented     

AC floating body effects and the resultant analog circuit issues insubmicron floating body and body-grounded SOI MOSFET's

We report the extensive study on ac floating body effects of different SOI MOSFET technologies. Besides the severe kink and resultant noise overshoot and degraded-distortion in partially depleted (PD) floating body SOI MOSFET's, we have investigated the residue ac floating body effects in fully depleted (FD) floating body SOI MOSFET's, and the different body contacts on PD SOI technologies. It is important to note that there is a universal correlation between ac kink effect and Lorentzian-like noise overshoot regardless of whether the body is floating or grounded. In addition, it was found that third-order harmonic distortion is very sensitive to floating body induced kink or deviation on output conductance due to the finite voltage drop of body resistance. These results provide device design guidelines for SOI MOSFET technologies to achieve comparable low-frequency noise and linearity with Bulk MOSFET's