Numerical simulations of light scattering by red blood cells

Scattering of electromagnetic waves from a red blood cell is simulated using the finite-difference time-domain method (FDTD), the Rytov approximation and the discrete dipole approximation (DDA). Both FDTD and DDA are full wave methods that give accurate results in a wide range of wavelengths. The Rytov approximation is a much simpler method that is limited to scattering angles within 30 degrees from the forward direction. The investigation comprehends different wavelengths and different orientations of the cell. It shows that the shape, volume, and orientation of the cell have a large influence on the forward scattering.     

Structural analysis of red blood cell membrane with an atomic force microscope

To evaluate the usefulness of the atomic force microscope (AFM) for structural analysis of biomedical samples and to determine suitable sample preparation methods for AFM observation, the membrane of human erythrocytes prepared by various methods for electron microscopy was examined by the AFM. Strand-like elevations with 20-50 nm in width, 30-80 nm in length and 3-5 nm in height were observed, which formed networks composed of squares, pentagons and hexagons on the cytoplasmic or back surface of the erythrocyte membrane. Using colloidal gold labelled antibody, this network was found to contain spectrin molecules. Therefore it was very likely that the undercoat molecules of the plasma membrane were imaged by AFM. A large number of gentle elevations 300-400 nm in diameter and 2 nm in height were found to be distributed uniformly on the extracellular or true surface of intact erythrocyte, presumably reflecting the presence of undercoat membrane skeleton on the cytoplasmic surface. However, no structure that seemed to be derived from glycocalyces was discernible on the true surface. Structure corresponding to the unit membrane or lipid bilayer structure observable by electron microscopy was not demonstrated in the cross-section of the membrane. In freeze-fractured samples, a large number of small particles that corresponded to the intramembranous particle were also demonstrated on the membrane halves. Since AFM allows depiction of the fine structures of biological samples with very simple sample processing at a resolution comparable to or exceeding that of SEM, imaging technology using AFM can be applied to obtain biomedical information. However, several problems have to be solved in future development of the equipment.     

一种红细胞光散射模型的研究

针对球形细胞模型理论与双凹圆盘状的红细胞在实际光散射法检测中的差异,根据细胞的类别特征,提出以扁椭球模型来模拟红细胞,以Rayleigh-Debye-Gans近似理论为基础,引入扁椭球的体极化率,得到了扁椭球模型的散射光公式,并进行数值模拟,研究其光散射特性。结果表明,扁椭球模型更精确地反映了红细胞光散射的真实情况,同时其前向、侧向及后向光散射精细谱的呈现,可以较容易地辨别病理状态的红细胞,能够较好地提高医学检验及诊断的精度,并可以应用于对红细胞的变形性研究。     

基于虚拟仪器的激光光斑自动采集与分析系统

为了得到激光光束的某些参量,为设计和改进激光器提供依据,建立了一套激光光斑自动采集与分析系统,搭建了实验平台,并编写了一套基于虚拟仪器开发平台LabVIEW及其图像处理软件包NI Vision的用于采集和分析激光光斑的软件。该软件能实时显示光斑中心位置的漂移轨迹、在x方向和y方向漂移的标准差及其随时间变化的趋势等,同时,还能对基模高斯光束进行分析。经过去噪处理的光斑图样能以3维灰度图的形式显示出来,得到任意剖面的光强信息,并以此进行高斯曲线拟合,得出拟合参量以判断光强曲线接近高斯曲线的程度。结果表明,这种系统可以动态地采集光斑信息并进行处理,具有实时性。     

Electric-field-induced anisotropy of thin semiconductor films

Assuming isotropic electrical properties for a semiconductor material, a mathematical derivation of a differential mobility tensor for carriers in thin semiconductor films with a tangential high electric field is represented.     

Using elastic light scattering of red blood cells to detect infection of malaria parasite

To develop noninvasive diagnosis of malaria, we studied the light-scattering pattern of healthy and 2% Plasmodium falciparum malaria parasitized red blood cells. By measuring the wavelength-dependent scattering at discrete angles of both forward and backward directions, we found that the signal can clearly distinguish between healthy and ring stage infected red blood cells. In particular, we demonstrated the first backward scattering measurement, which enables elastic light scattering as a promising noninvasive diagnostic tool for malaria.     

A generalized ionic model of the neuronal membrane electricalactivity

A new ionic model of the neuronal-membrane electrical activity has been developed. The proposed model generalizes those usually quoted in the literature, taking into account the significant ionic currents, the temperature dependence of the electrical parameters, and the stochastic synaptic inputs. The model allows the authors to simulate both the membrane firing activity, as a function of the temperature, and the membrane resistance behavior, as a function of temperature and of intracellular calcium concentration. The I-V nonlinear characteristic, together with histograms and correlograms of the time intervals between spikes, have been numerically reproduced. Various comparisons the authors have carried out with available experimental data show a good theoretical-experimental agreement     

用光镊研究稳恒磁场对血红细胞的活性影响

为了研究稳恒磁场对离体血红细胞的活性衰变产生的影响,采用非接触、无损伤的光镊技术进行了实验与分析。光镊中的高斯激光光束作用使红细胞发生形变,待细胞稳定后切断光路,得到形变血红细胞的相对形变量值,该量值大小与红细胞活性相关;对比了正常离体血液与静置于稳恒磁场中的红细胞活性衰变规律。结果表明,0.20T稳恒磁场可以提高红细胞的变形能力,增强红细胞的活性;同时加速了细胞体内能量的消耗,因离体环境没有能量的补充,能量的消耗加速了红细胞的衰老。这一结果为磁场对细胞的活性影响和动力学分析提供了一些参考。     

低强度激光照射对离体家兔红细胞膜磷脂成分及电泳率的影响

目的:探讨低强度激光对离体家兔红细胞膜磷脂成分及电泳率的影响.方法:用低强度激光照射家兔红细胞和血小板,以薄层色谱扫描法和显微(细胞)电泳法测定.结果:实验组红细胞膜磷脂成分中磷脂酰胆碱显著增多(p＜0.01),而鞘磷脂类、磷脂酰乙醇胺都程度不同的减少(p＜0.05),特别是磷脂酰丝氨酸含量、鞘磷脂类/磷脂酰胆碱及磷脂酰丝氨酸/磷脂酰胆碱比值显著减小(p＜0.01).血小板及红细胞的电泳率显著高于对照组.结论 低强度激光照射可改变离体家兔红细胞膜磷脂成分和电泳率.     

不同的辐照方法对钴^60辐照红细胞的损伤

目的：评估不同的辐照方法对MAP保存液中红细胞造成的影响及存储损伤。方法：将滤除白细胞的红细胞悬液分三组．对照组不予辐照,即刻辐照组在采集后立刻辐照,14日辐照组在保存14日后进行辐照。在储存期的1、7、14、21、28、35天检测三组红细胞钾离子浓度、平均细胞体积及红细胞刚性指数,结果：辐照前14日辐照组刚性指数升高缓慢,辐照后升高加速,但至第35天时仍低于即刻辐照组。这种变化规律同样可以见于MCV与钾离子浓度检测。结论：血站发血前辐照红细胞悬液的方法是合理的。     

Electric-field-induced modification of the optical properties of CuI crystals

The study is concerned with the effect of a dc electric field applied to copper iodide crystals on the resistivity of the crystals and their transparency and luminescence in the visible and ultraviolet spectral regions. It is shown that the conductivity, transparency, and edge luminescence intensity of the crystals decrease upon application of an electric field at room temperature with characteristic times of about 10 min. The reversibility of these processes, associated with the formation and diffusion of donor- and acceptor-type intrinsic defects (Cu _i and V _Cu) in the crystal lattice of the CuI compound, is established.     

Quantitative evaluation of the surface membrane receptors of leukemic cells to blood serum transcobalamin-II

Serum protein transcobalamin II (TC-II) is responsible for transport of cobalamins into mammalian cells. A method of quantitative estimation of plasma membrane receptors of hemopoietic cells to TC-II cobalamin complex is suggested. Analysis of mouse leukemia L1210 cells includes the saturation of radiolabelled ligand-receptor complex with papain. The number of receptors and 57CoCNCbl content in one cell is determined by differentiated radioactivity count of solubilized protein complexes and of cytoplasm.     

Surface membrane receptors, differentiation antigens and cytochemical characteristics of blood cells in acute lymphoblastic leukemia in children

The study of surface membrane receptors by the methods of combined patch-formation and cytochemical markers of blast cells has revealed 57 cases of childhood ALL which were classified as non-T, non-B cell, pre-T, T- and B-cell forms. Using the panel of monoclonal antibodies (IKO-1, 02, 10, 11 and I10P-1-8) the surface differentiation antigens have been studied in certain patients. Significance of cytochemical studies for definition of main forms of acute leukemias and immunocytology for differentiation of some types of ALL was suggested.     

Determination of the red blood cell ability to traverse cylindricalpores

An expression relating the red blood cell (RBC) volume and membrane surface area to the pore minimum radius/maximum length which the cell is able to traverse is derived. The application of this analytical model to design/specification of filters for RBC deformability evaluation is presented. The passage of the RBC's through relatively long (10 μm or more) submicron radii pores, which the developed model demonstrates, is also discussed     

一种动态显微红细胞图像处理分析方法研究

以硅微通道红细胞变形性测量系统采集到的动态显微红细胞图像为例,探讨了一种有效的动态显微细胞图像处理分析方法.包括可行的图像滤波、图像增强和图像抖动消除等预处理;利用分段多帧提取背景序列以消除背景,再获得红细胞轮廓;并进行周长、面积、质心等细胞图像信息处理分析.针对实际动态显微红细胞图像(序列)的处理也验证了方法的有效性...     

He-Ne激光照射对红细胞变化的研究

He-Ne激光对红细胞的作用至今尚有争论，有的认为He-Ne激光可引起周围血液和凝血系统的变化，提高血液中红细胞和血红蛋白的含量。1962年巴黎国际血液研究所报告：激光可以对红细胞造成损害，而对白细胞没有引起损害。     

Synthesis and photophysical characterization of an ionic fluorene derivative for blue light-emitting electrochemical cells

A highly fluorescent an ionic fluorene derivative 1 was synthesized and its photophysical, electrochemical and electroluminescence characteristics were investigated. Deep blue emissions were observed for compound 1 in solid as well as in dilute solutions. The synthesized compound shows high fluorescence quantum yield around 77% indicates that compound 1 can perform its role as efficient ionic emitter in LEC devices. Light-emitting electrochemical cell (LEC) devices were fabricated incorporating compound 1 without (device I) and with (device II) ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM·PF₆). Devices I and II exhibited blue electroluminescence maximum centered at 455 and 454 nm with CIE coordinates of (0.15, 0.21) and (0.16, 0.22), respectively. Maximum luminance and current efficiency of 1105 cd m⁻² and 0.14 cd A⁻¹ respectively, has achieved for device I while that of device II resulted in 1247 cd m⁻² and 0.14 cd A⁻¹ respectively.     

低强度激光照射对离体正常人红细胞的影响

以正常人血液为样品研究低强度激光对红细胞流变学特性的影响。取正常人血液分成两份分别在2mW、4mW、6mW、8mW的功率下照射30分钟,观察在不同功率的低强度He-Ne激光在相同照射时间下,红细胞的变形性、取向、膜流动性、微黏度、各向异性和渗透脆性的变化情况。结果表明低强度激光血液照射对正常红细胞的影响无统计学上的差异。     

Automated segmentation of cells with IHC membrane staining

This study presents a fully automated membrane segmentation technique for immunohistochemical tissue images with membrane staining, which is a critical task in computerized immunohistochemistry (IHC). Membrane segmentation is particularly tricky in immunohistochemical tissue images because the cellular membranes are visible only in the stained tracts of the cell, while the unstained tracts are not visible. Our automated method provides accurate segmentation of the cellular membranes in the stained tracts and reconstructs the approximate location of the unstained tracts using nuclear membranes as a spatial reference. Accurate cell-by-cell membrane segmentation allows per cell morphological analysis and quantification of the target membrane proteins that is fundamental in several medical applications such as cancer characterization and classification, personalized therapy design, and for any other applications requiring cell morphology characterization. Experimental results on real datasets from different anatomical locations demonstrate the wide applicability and high accuracy of our approach in the context of IHC analysis.     

Power Doppler ultrasound evaluation of the shear rate and shearstress dependences of red blood cell aggregation

The use of power Doppler ultrasound at 10 MHz is evaluated as a method to study the shear rate and the shear stress dependences of red blood cell aggregation. This evaluation was based on 6 in vitro experiments conducted in a 1.27-cm diameter tube under steady flow conditions. Porcine whole blood was circulated in the flow model at flow rates ranging between 125 to 1500 ml/min (mean shear rate across the tube ranging between 6 and 74 s^-1). For each flow condition, the variation of the Doppler power across the tube and the velocity profile were measured by moving the Doppler sample volume across the tube diameter. For each radial position, the shear rate within the Doppler sample volume was also determined by considering the radial power pattern of the ultrasound beam. To estimate the shear stress within the Doppler sample volume, the apparent viscosity of blood samples withdrawn from the flow model was measured for each experiment. The variation of the Doppler power as a function of the shear rate within the sample volume showed a rapid reduction of the power between 1 and 5 s^-1, a transition region between 5 and 10 s^-1, and a very slow reduction beyond 10 s^-1. Little variation of the Doppler power was measured for shear stress higher than 2 dyn/cm. The maximum Doppler power for all flow rates was usually found near the center of the tube. Based on the ultrasonic scattering models, which predict that the Doppler power is related to the volume square of the scatterers, the method described in the present study showed a very high sensitivity to the presence of red blood cell aggregation for shear rates below 10 s^-1