Polarographic characteristics of DNA preparations isolated from the tissues of rats with Shvets' erythromyelosis

The polarographic method is used to show that the DNA preparations from the liver, spleen and tumour of leukemic rats in contrast to these preparations from the liver and spleen of the control ones possess a sharply marked electrochemical activity manifested by two peaks (peak I and peak II) in the region of the negative potential values. Peak I located in the region from--1.05 V to--1.30 V is determined by the activity of adenine and cytosine amine groups whereas peak II (from--1.45 V to--1.60 V) is caused by a protein component.     

Dirichlet Priors for MAP Inference of Protein Conformation Abundances from SAXS

Estimation of mixture coefficients of protein conformations in solution find applications in understanding protein behavior. We describe a method for maximum a posteriori (MAP) estimation of the mixture coefficients of ensemble of conformations in a protein mixture solution using measured small angle X-ray scattering (SAXS) intensities. The proposed method builds upon a model for the measurements of crystallographically determined conformations. Assuming that a priori information on the protein mixture is available, and that priori information follows a Dirichlet distribution, we develop a method to estimate the relative abundances with MAP estimator. The Dirichlet distribution depends on concentration parameters which may not be known in practice and thus need to be estimated. To estimate these unknown concentration parameters we developed an expectation-maximization (EM) method. Adenylate kinase (ADK) protein was selected as the test bed due to its known conformations Beckstein et al. (Journal of Molecular Biology, 394(1), 160 1). Known conformations are assumed to form the full vector bases that span the measurement space. In Monte Carlo simulations, mixture coefficient estimation performances of MAP and maximum likelihood (ML) (which assumes a uniform prior on the mixture coefficients) estimators are compared. MAP estimators using known and unknown concentration parameters are also compared in terms of estimation performances. The results show that prior knowledge improves estimation accuracy, but performance is sensitive to perturbations in the Dirichlet distribution’s concentration parameters. Moreover, the estimation method based on EM algorithm shows comparable results to approximately known prior parameters.     

大花蕙兰(Cymbidium faberi)花叶病病原的电镜诊断

蕙兰又称夏兰、九节兰、九子兰等,近年来昆明等地有多家公司大规模栽培。通过调查我们发现在大花蕙兰中发生一种传染性很强的花叶病,可通过叶片的摩擦接触传染,感染病毒严重将引起植株产生花叶和矮化现象,甚至可在短时期内引起植株死亡。电镜负染色法观察到大量杆状病毒粒子。以往     

Functional analysis of mammalian genes using amphibian embryonic cells

We describe a method that contributes to the analysis of the functions of mammalian genes by the use of amphibian embryos and electron microscopy. Following forced expression of specific mammalian genes in amphibian embryos, we attempted to deduce the function of each gene from the ultrastructural changes in cell organelles caused by its overexpression. This method has been applied to the analysis of the functions of genes isolated from mammalian skeletal muscle and the results have shown it to be an effective technique for such studies. We present the results of our experimental studies using this method and discuss its usefulness in analyzing mammalians genes.     

油田开发数据库应用模型构建技术研究与应用

油田开发信息模型化组织是当前油田开发数据库建设过程中急需解决的问题.在明确油田开发专题应用对数据需求的基础上,建立应用模型构建流程及模型化实现手段,实现专业应用在信息方面的有效开发.应用实践证明,应用模型构建技术对于油田开发专题应用的数据组织是非常有效的.     

Interpolation of 2-D signals from their isolated zeros

In this paper, interpolation formulas are derived for the recovery of a two-dimensional (2-D) bandlimited signal from its isolated zeros. Different constellations of zero locations are considered. The interpolation formulas, based on Lagrange interpolation, are given both in Cartesian and in polar coordinates.     

Molecular Conformation and Applicaton of Stereoregular PMMA Langmuir-Blodgett Films

Molecular conformations of stereoregular poly(methyl methacrylate) (PMMA) monolayers have been investigated by scanning probe microscopes. Isotactic and syndiotactic PMMAs were found to have right and left hand helical structures, respectively. On the contrary atactic PMMA showed rather random arrangement of the chains. It has been demonstrated that the PMMA Langmuir-Blodgett(LB) films can be utilized to form nanoscale patterns down to 50 nm and to form a geodesic lens. It has also been manifested that the quantum efficiency of a polymer electroluminescent device can be significantly enhanced by inserting the PMMA LB films between the emitting layer and the cathode. All the applications utilize the unique characteristics of the LB films to form thin and uniform films in the molecular level.     

Thermal haemolytic threshold of human erythrocytes

Haemolytic thermal threshold of human erythrocytes has been determined by means of an especially designed microwave apparatus. Temperatures between 50 and 55 degrees C are necessary to produce an initial haemolysis of erythrocytes in the whole blood, while the thermal threshold drops to 37 degrees C for red blood cells suspended in buffered saline. Absorbed energy measurements permit the conclusion that the haemolytic effect is thermal in nature.     

两栖装甲车辆对抗双红外制导伪装方法研究

在分析两栖装甲车辆的双红外暴露特征、双红外制导抗干扰原理和常见的红外干扰技术的基础上,得出了在两栖装甲车辆对抗双红外制导的最佳伪装方法——人工水雾红外遮蔽技术。并利用Mie散射理论分析了单位喷水量条件下,水雾滴径与3～5 μm、8～14 μm波段衰减的关系,从理论上给出了水雾滴径的最佳尺寸,最后编程模拟计算了人工水雾的双红外遮蔽性能。     

Elevated agglutinability of erythrocytes in cancer patients

Mediated agglutination of erythrocytes was studied in the presence of concanavalin A (Con A). Agglutinability of erythrocytes from cancer patients was found to be higher than that of normal cells as a result of chemical factors present in the blood plasma which transform the cell surface, the number of Con A receptors remaining unchanged. It is concluded that increased agglutinability of erythrocytes from cancer patients is mainly due to a decrease in the negative charge of cells and the appearance of echinocytic forms.     

DNA computing from a signal processing viewpoint

In this article, an analysis of Adleman's experiment and a review of DNA computing applications from a signal-processing point of view are provided. In addition, certain key parts of DNA computing are emphasized, such as the code word design, to which the application of signal processing theory and techniques can offer significant advantages. The goal of this article is to introduce to the signal processing community a new unexplored area of research.     

Automated 3-D reconstruction of the surface of live early-stage amphibian embryos

Although three-dimensional (3-D) reconstructions of the surfaces of live embyos are vital to understanding embryo development, morphogenetic tissue movements and other factors have prevented the automation of this task. Here, we report an integrated set of software algorithms that overcome these challenges, making it possible to completely automate the reconstruction of embryo surfaces and other textured surfaces from multiview images. The process involves: 1) building accurate point correspondences using a robust deformable template block matching algorithm; 2) removing outliers using fundamental matrix calculations in conjunction with a RANSAC algorithm; 3) generating 3-D point clouds using a bundle adjustment algorithm that includes camera position and distortion corrections; 4) meshing the point clouds into triangulated surfaces using a Tight Cocone algorithm that produces water tight models; 5) refining surfaces using midpoint insertion and Laplacian smoothing algorithms; and 6) repeating these steps until a measure of convergence G, the rms difference between successive reconstructions, is below a specified threshold. Reconstructions were made of 2.2-mm diameter, neurulation-stage axolotl (amphibian) embryos using 44 multiview images collected with a robotic microscope. A typical final model (sixth iteration) contained 3787 points and 7562 triangles and had an error measure of G = 5.9 microm.     

Antitumor effectiveness of chalone-like proteoglycans isolated from normal and tumor tissues

Chalone-like proteoglycans (PG) have been isolated from 22a hepatoma, spontaneous adenocarcinoma of the mammary gland of C3H/He mice and from transplanted X-ray-induced lymphoma in C57Bl mice. It has been found that the biological activity of these PG was considerably weaker than that of PG taken from the liver, mammary gland and spleen of cattle. PG from 22a hepatoma produced a weaker tissue-specific antimitotic effect as against PG from the liver when acting on the liver cells of 6-day C57Bl mice, while the lymphoma PG under these conditions was ineffective. PG from the liver and mammary gland inhibited the growth of certain transplanted tumours in vitro. The lymphoma PG has stimulated the tumour growth.     

Conformation of Multilevel Current Source Converter Topologies Using the Duality Principle

This paper explores the issue of constructing multilevel current source converter (MCSC) topologies using the duality principle. Three circuit cells for MCSCs are derived from the applications of the duality on the three common leg circuit cells of multilevel voltage source converters (MVSCs). Based on the presented three cells, three families of MCSC topologies, which are also corresponding to three families of MVSCs, are constructed. Analytical results show that these derived MCSCs and their corresponding MVSCs present analogous features such as the ac side currents/voltages and inductor/capacitor currents/voltages, though they are not direct dual structures. Some experimental results are given to verify the presented MCSC structures.      

A low molecular-weight angiogenesis factor isolated from Lewis lung carcinoma

A fraction with the angiogenetic activity was obtained by the methods of the gel-chromatography on G-100 and the ion-exchange chromatography on DEAE-cellulose. Treatment of this fraction with the 10% water isopropanol solution has led to dissociation of the obtained material with a release of a low-molecular-weight angiogenic factor with a high angiogenic activity when tested on the chorioallantoic membrane. The molecular weight of this factor (300-600 daltons) was estimated by the chromatography on the biogel P2.     

The origin of 5 S DNA from tumor ascitic fluid

Certain properties of DNA from chromatin mononucleosomes of the normal rat liver were compared with those of 5 S DNA from the ascitic fluids of human and animal tumours. Both DNA proved to be identical by their electrophoretic mobility in 8% PAAG and by characteristic violet tinge when stained with methylene blue. Thermal and alkaline denaturation causes less degradation of mononuclesome DNA than 5 S DNA. It is shown that 5 S DNA of ascitic fluid of Ehrlich ascite tumour of mice hybridizes with a higher amount of mouse genome DNA restricts. An assumption is advanced that 5 S DNA is either a product of chromatin decay to mononucleosomes or a product of extracopial synthesis and is delivered to ascitic fluid surrounding the tumour cells as a result of activation of Ca, Mg-dependent endonuclease of the latter.     

Hemolytic resistance of erythrocytes in the development of experimental tumors

Peculiarities of variations in the mechanical resistance of erythrocytes from mice with tumours were studied depending on the growth stage of tumours (lymphoma NK/Ly and sarcoma S-37). The accumulation of erythrocytes with the increased mechanical resistance at the stage of rapid tumour development (on the 4 to 6th days) was revealed by the kinetic method of ultrasonic haemolysis. Quantitative parameters of ultrasonic haemolytic resistance of erythrocytes from normal and tumour-bearing mice were used as criteria for the red blood cell changes depending on the cell age in blood. The increase of haemolytic resistance at the rapid stage of tumour growth may be caused by a higher number of "young" erythrocytes in blood. Ultrasonic haemolytic resistance increases when there is no changes in the erythrocyte quantity and hemoglobin concentration. The kinetic study of ultrasonic haemolysis of the erythrocytes isolated from peripheric blood permits estimating the reaction of the blood forming organs to the origin and development of tumours.     

一株来自金雕的霉形体的形态研究

本文利用航向电镜观察了一株来自金雕的形体在培养过程中的各种形态。结果表明该霉形体的形态极其多变，主要有丝状分枝体、原质小体、较大型体和巨大型体。它们在固体培养和液体培养等条件下的形态变化各有特点和规律。同时还进一步证实，除原质小体外的细胞均有直接的分裂连续增殖，而原质小体由丝状分枝体和较大型体产生，经转主为其它形态后再增殖。