Analysis of enoyl-coenzyme A hydratase activity and its stereospecificity using high-performance liquid chromatography equipped with chiral separation column

Enoyl-coenzyme A (CoA) hydratase catalyzes the hydration of trans-2-enoyl-CoA to yield 3-hydroxyacyl-CoA during fatty acid degradation (β-oxidation). Although much research has focused on the stereospecificities of 2-enoyl-CoA hydratases, a direct quantification of the production of 3(R)- and 3(S)-hydroxyacyl-CoA has not yet been established. Therefore, we developed a method of concurrently quantifying 3(R)- and 3(S)-hydroxyacyl-CoA using high-performance liquid chromatography (HPLC) equipped with a chiral separation column. The optimized conditions for the separation of 3(R)-, 3(S)-hydroxyhexadecanoyl-CoA and trans-2-hexadecenoyl-CoA, were determined to be as follows: mobile phase of 35/65 (v/v) of 50 mM phosphate buffer (pH 5.0)/methanol; flow rate of 0.5 mL/min; detection at 260 nm; and column temperature of 25°C. This method was applied to subcellular fractions of rat liver; the results directly confirmed that 3(S)-hydroxyhexadecanoyl-CoA is the dominant product obtained from the heat-stable enoyl-CoA hydratase-catalyzed reaction of trans-2-hexadecenoyl-CoA. Finally, the stereospecificities of L-bifunctional protein (L-BP) and D-bifunctional protein (D-BP) were reinvestigated using this method, and it was confirmed that L- and D-BP yielded 3(S)- and 3(R)-hydroxyhexadecanoyl-CoA were yielded from trans-2-hexadecenoyl-CoA, respectively. 3(R)-Hydroxyacyl-CoA is a peroxisomal β-oxidation-specific intermediate. Therefore, this method is potentially useful not only studies regarding the stereochemistry of enoyl-CoA hydratase but also for the diagnosis of diseases caused by defects of peroxisomal enoyl-CoA hydratase.     

Phase relation between offices in a mutually synchronised system

Although a common system frequency is established in mutually synchronised system, some phase difference exists between offices. Analyses of the phase difference and the system-frequency jump due to the change in transmission delay are given, assuming the sawtooth characteristics for the phase comparators.     

Glyme-based nonaqueous electrolytes for rechargeable lithium cells

Poly(ethylene glycol)dimethyl ethers [(CH₃O(CH₂CH₂O)_nCH₃, n = 1, 2, 3, and 4)] are generally known as “glymes”. This study examines the conductivity, lithium ion solvation state and charge-discharge cycling efficiency of lithium metal anodes in glyme-based electrolytes for rechargeable lithium cells. 1 M (M: mol l⁻¹) LiPF₆ was used as the solute. The properties of the glymes were investigated by using a ternary mixed solvent consisting of n-glyme, ethylene carbonate (EC) and methylethylcarbonate (MEC). This was because the solubility of LiPF₆ is far less than 1 M in an n-glyme single solvent. The glyme solutions exhibited higher conductivity and higher lithium cycling efficiency than EC/MEC. The conductivity tended to increase with decreases in ethylene oxide chain number (n) and solution viscosity. The decrease in the solution viscosity resulted from the change in the lithium ion solvation structure that occurred when a glyme was added to EC/MEC. The selective solvation of the glyme with respect to lithium ions was clearly demonstrated by -NMR measurements. The lithium cycling efficiency value depended on the charge-discharge current (I_ps). When n increased there was an increase in lithium cycling efficiency at a low I_ps and a decrease in the reduction potential of the glymes. When the conductivities including those at low temperature (below 0 °C), and charge-discharge cycling at a high current are taken into account, di- or tri-glyme is superior to the other glymes tested here.     

硫酸溶液中SUS304不锈钢旋转圆盘电极电流振荡现象的研究

硫酸溶液中SUS304不锈钢旋转圆盘电极在正向电位扫描时产生电流振荡现象。振荡电流所对应的电位范围以及电流振荡幅度与溶液温度,硫酸浓度、电位扫描速度以及电极旋转速度存在着对应关系.在电位线性扫描条件下,溶液温度高于35.0℃、硫酸浓度大于2.5mol·L~(-1)以及电极旋转速度不大干1000rpm时,可观测到电流振荡现象。电流振荡现象的产生与电极溶解过程、Cr_2O_7~(2-)的生成。O_2的离析及MCr_2O_7盐膜的生成和裂解有着密切的关系。     

System for reconstruction of three-dimensional micro objects from multiple photographic images

We introduce a system to reconstruct a three-dimensiojnal (3D) polygonal model of 3D micro objects with outer dimensions ranging from several hundred microns to several millimeters from multiple two-dimensional (2D) images of an object taken from different views. The data acquisition system consists of a digital microscope that captures still images at a resolution of 1600 × 1200 pixels and a computer-controlled turntable. We employ the shape-from-silhouette (SFS) method to construct a voxel-based 3D model from silhouette images. The concave shapes are further carved by using the space carving technique. In order to make the resulting model compatible with a commercial CAD/CAM system, the voxel model is converted into a triangular mesh using the marching cubes algorithm. Because the mesh generated from the voxel model by using the marching cubes algorithm inherits the staircase effect, the mesh is adjusted to recover the object precisely by using silhouette images. Finally, we evaluate the accuracy of the proposed method. The reconstructed models of complex micro objects indicate the effectiveness of the 3D shape reconstruction system for micro objects.     

Highly conductive bridges between graphite spheres to improve the cycle performance of a graphite anode in lithium-ion batteries

Spherical carbon-coated natural graphite (SCCNG) is a promising anode material for lithium-ion batteries, but the smooth surface of graphite spheres is difficult to wet with an aqueous binder solution, and lacks electrical contacts. As a result, the cycle performance of such a graphite anode material is not satisfactory. An effective method has been introduced to tightly connect adjacent SCCNG particles by a highly conductive binder, viz. acetylene black bridges. The effect of the conductive bridges on the cyclability of SCCNG electrode has been investigated.     

Three-stage time-division switching network with pulse-shifting junctor as alternate route

The configuration of a 3-stage time-division switching network which has pulse-shifting junctors as the alternate route as well as direct junctors is proposed. A computer simulation to estimate the blocking probability of the system is performed, and proves the system to be nearly as efficient as the switching network without time-slot mismatch loss.     

A compact programming environment for microprocessor-based controllers

To write a reliable program in an assembly language for microprocessor-based controller, we introduce data abstraction facility into an assembly language. For this purpose, we has designed and implemented ADT-RASM86 and its symbolic debugger. This paper presents the figure of the system and describes how the system is effective for writing a reliable program for microprocessors.     

Nonlinear motion of magnetization in superfluid3He-B. The Leggett-Takagi spin relaxation effect in the pulsed NMR configuration

The recovery motion of the magnetization and the associated motion of the order parameter for the pulsed NMR geometry in superfluid³He-B are investigated by solving the Brinkman equations including the Leggett-Takagi spin relaxation effect. It is found that the relaxation of longitudinal magnetization strongly depends upon the initial tip angles according to both the numerical and adiabatic perturbation methods. For large tip angles, these equations yield square-root and linear types of recovery. For small tip angles near the magic angle ₀=cos^–1 (–1/4), the longitudinal magnetization does not recover to the full equilibrium value, and the transverse magnetization shows time-dependent resonance shifts arising from the relaxation effect.