Morphometric model of lymphocyte as applied to scanning flow cytometry

The peripheral blood lymphocytes of normal individuals are investigated by methods of specialized light microscopy. Lymphocytes as a whole and T-cell subpopulation are considered. Lymphocyte structure is characterized with reference to polarizing scanning flow cytometry. The lymphocyte and lymphocyte nucleus shapes are analyzed. Linear correlation dependence between sizes of lymphocyte and its nucleus is indicated. A morphometric model of a lymphocyte is constructed using the obtained data. The findings can be used, for instance, as input parameters to solve the direct and inverse light-scattering problems of turbidimetry, nephelometry, and flow cytometry.     

Application of Chimera grid to modelling cell motion and aggregation in a narrow tube

A computational scheme using the Chimera grid method is presented for simulation of three‐dimensional motion and aggregation of two red blood cells (RBCs) in a narrow tube. The cells are modelled as rigid ellipsoidal particles; the computational scheme is applicable to deformable fluid‐filled particles. Attractive energy between two RBCs is modelled by a depletion interaction theory and used for simulating aggregation of two cells. Through the simulation, we show that the Chimera grid method is applicable to the simulation of three‐dimensional motion and aggregation of multiple RBCs in a microvessel and microvascular network. Copyright © 2006 John Wiley & Sons, Ltd.     

Flow injection preconcentration by chemofiltration and spectrophotometric determination of Gd

A new on-line Gd preconcentration and determination system associated to flow injection (FI) method was developed. 2,2′-(1,8-dihydroxy-3,6-disulfonaphthylene-2,7-bisazo) bisbenzenearsonic acid (Arsenazo III) was used as a complexing agent at pH 2.5. A reactor containing the polyamide membrane was used for the retention of the Gd complex by chemofiltration. The complex was then removed from the reactor with buffer solution pH 9. The variables affecting the combined on-line preconcentration-absorptiometric method have been evaluated and optimised. The coupling of the on-line preconcentration and spectrophotometric flow through detection led to a detection limit of 15 μg l⁻¹ for a preconcentration time of 5 min at 2 ml/min. The method was successfully applied to biological samples.     

间接原子发射光谱法测定碘解磷定

研究了等离子发射光谱法间接测定碘解磷定。在pH5．0的溶液中，当四苯硼钠过量时可完全沉淀碘解磷定，在滤液中加入过量的氯化钾沉淀剩余的四苯硼钠，再测定滤液中过量的钾，可以计算得到碘解磷定的含量。方法简单快速，回收率在96％～102％之间，相对标准偏差为1．7％。     

Order Determination for Multivariate Autoregressive Processes Using Resampling Methods

LetX₁, …, X_nbe observations from a multivariate AR(p) model with unknown orderp. A resampling procedure is proposed for estimating the orderp. The classical criteria, such as AIC and BIC, estimate the orderpas the minimizer of the function[formula]wherenis the sample size,kis the order of the fitted model, Σ²_kis an estimate of the white noise covariance matrix, andC_nis a sequence of specified constants (for AIC,C_n=2m²/n, for Hannan and Quinn's modification of BIC,C_n=2m²(ln ln n)/n, wheremis the dimension of the data vector). A resampling scheme is proposed to estimate an improved penalty factorC_n. Conditional on the data, this procedure produces a consistent estimate ofp. Simulation results support the effectiveness of this procedure when compared with some of the traditional order selection criteria. Comments are also made on the use of Yule–Walker as opposed to conditional least squares estimations for order selection.     

肝硬化合并低氧血症31例临床研究

为探讨肝硬化患者的血氧变化与临床关系，以肝炎后肝硬化患者31例为观察组（A组），采用血气分析仪测定其动脉血氧分压（PaO2)及动脉血氧饱和度（SaO2)，并以正常人15例作对照组（B组）进行比较结果表明，A组的低氧血症发生率为41％，B组为0。肝硬化患者低氧血症的发生率高，其严重程度与Child-Pugh分级有关。早期发现低氧血症并予以治疗有助于改善肝硬化患者的预后。     

在不同空间高度下遥感FTIR定量测定大气中的某些VOCs

应用遥感FTIR在不同高度下,测定大气中的有毒易挥发有机化合物(VOCs)——甲苯,正己烷和丙酮的浓度。并对相同的高度下,测量的精度做了研究。当高度为0.61 m时,所测得的气体的浓度值最大,而当仪器高度为0.36和0.86 m时,测得的浓度则较低。实验结果表明,在不同的高度下VOCs的挥发是不同的。     

确定地下水污染强度的反问题方法

探讨了山东省淄博市张店区沣水南部区域地下水的硫酸污染问题 .根据观测井点的浓度数据 ,将硫酸污染强度的识别问题作为一个已知终值数据的源项反问题 .应用积分恒等式方法分析了未知源函数与已知数据间的数据相容性 ,进而基于最优化策略进行了数据反演 ,计算结果与实际估计值基本吻合     

Analytical applications of photon correlation spectroscopy for size distribution measurements of natural colloidal suspensions: capabilities and limitations

Particles are ubiquitous in all natural systems and play an important role in the control and fate of nutrients and pollutants. Currently, only limited information is available concerning particle number and size distributions, owing to the problems involved in their experimental determination. In the present paper, limitations and optimal conditions for particle size determinations of environmental samples using photon correlation spectroscopy are studied. The detection limit, the effects of polydispersity of the sample and the refractive index value are discussed based on results obtained with synthetic colloids. The photon correlation spectroscopic determination of particle size distributions in real aquatic systems is also presented in the second part of the paper.