Gelation Mechanism of Soybean 11S Globulin: Formation of Soluble Aggregates as Transient Intermediates

Thermal association-dissociation behavior of soybean 11S globulin was investigated by sucrose density gradient centrifugation and polyacrylamide gel electrophoresis. Soluble aggregates with a molecular weight of 8 × 10⁶ were formed when 0.5% and 5% protein solutions were heated for 1 min at 100°C. At the lower protein concentration, subsequent heating caused disappearance of the soluble aggregate followed by complete dissociation into acidic and basic subunits. At the higher concentration, however, subsequent heating caused formation of highly polymerized aggregates, and gel was formed after 5 min of heating. The soluble aggregates appear to be transient intermediates in the course of gel formation of 11S globulin.     

跳跃式移动机构的移动机理及实验研究

介绍了一种新型跳跃式移动机构,阐述了该机构的移动机理及其控制方法.跳跃式移动机构采用小型振动电机作为驱动,利用电机内偏心轮的旋转所产生的周期性的向心力及与工作表面的间歇性摩擦力的共同作用,实现机构的跳跃移动,两个不同放置位置的电机的组合运用,可实现机构可调速的直线运动和回转运动,通过一系列实验.验证了跳跃式移动机构可实现二维平面内的自由移动.     

Physical Properties of Soy Bean and Broad Bean 11S Globulin Gels Formed by Transglutaminase Reaction

Physical properties of transglutaminase-induced glycinin and legumin gels were compared with thermally induced gels. Results of deformation tests showed that transglutaminase-induced gels were more rigid and elastic than thermally induced gels. From creep compliance tests, all elastic moduli and viscosities except Newtonian viscosity were higher for transglutaminase-induced gels. Electron micrographs revealed that network structures of transglutaminase-induced gels were composed of larger unit particles forming more developed strands and clusters. More rigid and elastic gels were formed from glycinin as compared to legumin by both gelling methods.     

Electron holographic observation for biological specimens: electron holography of bio-specimens

Electron holography has been applied to the observation of biological filaments. The technique has some advantages over conventional imaging for observing weak-phase objects such as small unstained biological structures. To avoid artificial structural transformation of the sample owing to the interaction with the supporting film, a holey carbon film was used to support the filaments. A tobacco mosaic virus bridged over a hole was observed as a cylindrical shape; the contrast distribution across the filament represents its actual shape, which is difficult to obtain with conventional transmission electron microscopy. A number of technical limitations which at present prevent high-resolution structure analysis of biological macromolecules by electron holography are discussed in this report.     

液滴机械手的数值仿真与试验研究

为分析液滴机械手的控制机理, 建立液滴机械手的流体动力学仿真模型,仿真分析液滴机械手的控制机理,研究机械手端面形成液滴的形态跟随机械手端面形状的变化关系,讨论影响液滴机械手性能的因素,并通过试验验证仿真模型的正确性和提出方法的可行性．数值仿真和试验结果表明:通过控制各钨丝棒的上下移动量,可以改变液体和各钨丝棒的接触壁面,使机械手端面形成液滴的形态随之改变;基于表面张力吸附在液滴上的微小部件的姿态将随着液滴形态的改变而变化,从而可以实现对于微小部件姿态的控制．适当调整机械手的参数,如钨丝棒的数目、尺寸、各钨丝棒的移动量,以及改变液滴的性质等,可以满足微装配过程中各种操作目标的要求．     

Chaos and bifurcation in numerical computation by the Runge-Kutta method

In this paper the chaotic phenomenon and bifurcation in numerical computation using the Runge-Kutta method to discretize the nonlinear differential equation are investigated. It is shown that the bifurcation condition in the discretized equation is given by the eigenvalue of the jacobian matrix of the original differential equation. As an example, the bifurcation and chaos when a second-order nonlinear equation is discretized by the Runge-Kutta method is investigated and it is shown that the scenario from a stable fixed point to chaos when the fourth-order Runge-Kutta method is applied is quite different from those of the second-order Runge-Kutta method     

Thermal Gelation Mechanism of Legumin from Broad Beans

The legumin formed a gel through formation of soluble aggregates and their juncture. Electron microscope studies indicated the legumin molecules associated to form strands. These strands then formed network-like structures, finally resulting in gel formation. The thickness of those strands and network constituents was irregular (8.3 to 36 nm). A presumed process of thermal legumin gelation was hypothesized. A comparison of gelation behaviors in legumin and in glycinin was also studied.     

基于漩流的细胞姿态控制方法

细胞姿态调整是生物工程显微操作中一项非常重要的工作。提出通过两微管喷射流体产生漩流,漩流带动细胞转动,进行非接触式的细胞姿态控制的方法。改变微管之间的相对位置、喷射速度和微管内径等参数,可以控制微管之间产生的漩流强度、尺寸,以适应不同尺寸、形状的细胞以及培养溶液的变化,使显微操作更为方便。建立显微操作环境下微流场漩流中细胞运动模型,模拟微观尺度下利用微流体产生漩流和细胞在漩流中的运动,仿真分析微管相对位置、喷射速度等参数对漩流及细胞运动特性的影响。通过试验进一步研究微流场中漩流的产生以及不同形状漩流作用下细胞的运动特性,得到与数值计算结果相一致的结论。     

超微量点胶方法与实验

针对微装配/密封工程对用胶量超微化(≤1 pL)的需求,提出了一种既适用于接触式点胶,也适用于非接触式点胶的超微量点胶方法.采用移液针穿过装有胶液的玻璃微管,在移液针先端吸附微小胶滴,当移液针先端靠近点胶面时,其先端吸附的微小胶滴与点胶面接触,移液针离开点胶面后,微小胶滴的一部分将残留在点胶面上,实现超微量点胶.通过匹配点胶的参数,实现点胶量的控制.该方法可以适用于任何黏度(1～3.5×105 cP)的胶液、任意空间方向的超精密点胶.实验讨论了移液针直径和点胶距离(移液针先端与点胶面的距离)对点胶性能(胶斑直径)的影响;在此基础上,匹配移液针直径、点胶距离、玻璃微管内径和点胶速度等参数,实现了胶液黏度为971 cP,点胶量为40 fL、170 fL、180 fL在3种亲水性不同的点胶面上的微量点胶;以及胶液黏度为3×104 cP,胶斑直径为243.9 μm时的超微量点胶.实验结果验证了提出方法的可行性.