Suppression of Martensitic Transformation in Co<Subscript>2</Subscript>Cr(Ga,Si) Heusler Alloys by Thermal Cycling

We have investigated the influence of thermal cycles on martensitic transformation of a Co₂Cr(Ga,Si) ferromagnetic Heusler alloy. The as-quenched specimen exhibits successive L2₁(L)–D0₂₂–L2₁(H) martensitic transformation in the cooling process, which is known as reentrant martensitic transformation. However, heating to 800 K (527 °C) for reverse D0₂₂–L2₁ transformation with a rate of 10 K/min (10 °C/min) stabilizes the parent phase, meaning that the martensitic transformation is suppressed by the thermal cycles. We found precipitate after thermal cycles, and it will be the reason for the stabilization of parent phase.     

Electrophoretic cell manipulation and electrochemical gene-function analysis based on a yeast two-hybrid system in a microfluidic device

A novel microfluidic device with an array of analytical chambers was developed in order to perform single-cell-based gene-function analysis. A series of analytical processes was carried out using the device, including electrophoretic manipulation of single cells and electrochemical measurement of gene function. A poly(dimethylsiloxane) microstructure with a microfluidic channel (150 microm in width, 10 microm in height) and an analytical chamber (100 x 20 x 10 microm (3)) were fabricated and aligned on a glass substrate with an array of Au microelectrodes. Two microelectrodes positioned in the analytical chamber were employed as a working electrode for the electrophoretic manipulation of cells and electrochemical measurements. A yeast strain ( Saccharomyces cerevisiae Y190) carrying the beta-galactosidase reporter gene was used to demonstrate that the device could detect the enzyme. Target cells flowing through the main channel were introduced into the chamber by electrophoresis using the ground electrode laid on the main channel. When the cell was treated with 17beta-estradiol, gene expression was triggered to produce beta-galactosidase, catalyzing the hydrolysis of p-aminophenyl-beta- D-galactopyranoside to form p-aminophenol (PAP). The enzymatically generated PAP was detected by cyclic voltammetry and amperometry at the single-cell level in the chamber of the device. Generator-collector mode amperometry was also applied to amplify the current response originating from gene expression in the trapped single cells. After electrochemical measurement, the trapped cells were easily released from the chamber using electrophoretic force.     

Molecular cloning and high-level expression in Escherichia coli of fungal alpha-galactosidase from Absidia corymbifera IFO 8084

A cDNA encoding the alpha-galactosidase of Absidia corymbifera IFO 8084 was cloned and sequenced. The cloned DNA has a single open-reading frame consisting of 2190 base pairs, and the deduced amino acid sequence revealed that the mature enzyme consisted of 730 amino acid residues with a molecular mass of 82,712 Da. The native structure of the alpha-galactosidase of A. corymbifera IFO 8084 was determined to be a tetramer. Comparison with amino acid sequences of other alpha-galactosidase showed high homology with sequences of members of family 36. An expression vector, pET32Trx/galalpha, was constructed by introducing the cDNA coding region into a thioredoxin fusion system, pET32-Ek/LIC. The resulting transformant, pET32Trx/galalpha, overproduced the active enzyme as a thioredoxin fused form in the host Escherichia coli. By using His-binding metal affinity chromatography, recombinant alpha-galactosidase was purified to homogeneity in a single step. The purified recombinant fusion alpha-galactosidase showed properties very similar to the native alpha-galactosidase from A. corymbifera IFO 8084.     

Localized amyloidosis in squamous cell carcinoma of uterine cervix: electron microscopic features of nodular and star-like amyloid deposits

An ultrastructural study of amyloid deposits in four cases of squamous cell carcinoma of uterine cervix was performed. The amyloid deposits reacted with anti-keratin antiserum on frozen sections. Amyloid deposits showed nodular (4 cases) and star-like forms (3 cases). Nodular amyloid deposits were composed of slightly whorled fibrils, measuring 7-10 nm in width. Some of them contained cellular debris and thicker, more electron-dense filaments than amyloid fibrils. In three cases, filamentous tumour cells and filamentous masses were observed together with amyloid. Star-like amyloid deposits were composed of bundles of straight amyloid fibrils. Some of the tumour cells in contact with star-like amyloid deposits had deep cytoplasmic invaginations, where closely packed amyloid fibrils were arrayed in parallel fashion. In addition, a few tumour cells had membrane-bound amyloid fibrils in the cytoplasm. It is suggested that nodular amyloid deposits are derived from the tumour cells through filamentous degeneration. Amyloid fibrils in star-like amyloid deposits are thought to be formed within the cytoplasm or in the vicinity of invaginated cytoplasmic membranes of the tumour cells.     

低频调制型脉冲MIG焊接方法的工艺特点

介绍了低频调制型脉冲MIG焊接的方法原理和工艺特点。采用该焊接方法 ,可以得到美观的鱼鳞状焊缝表面 ,扩大可焊接头间隙的范围 ,有效抑制焊接气孔缺陷的发生 ,细化晶粒 ,降低裂纹敏感性     

Automatic heart-rate-based selection of pedal load and control system for electric cart

This paper describes an autoselection method for the pedal load of an electric cart, and the control system. The method checks the driver’s physical condition just before the start of driving, calculates the driver’s rating of perceived exertion, and uses that to automatically select a suitable pedal load. To ensure that the level of physical exertion is safe, the largest pedal load is determined on the basis of Borg’s CR10, the Karvonen formula, a pedaling experiment, and statistical data. A driver’s degree of fatigue is estimated from his heart rate, and a pedal load (between the largest and almost zero) is automatically selected. In addition, a dynamic output-feedback cart control system was designed that guarantees the stability of the cart system for any allowable pedal load. A stability condition is derived by employing the concept of dynamic parallel distributed compensation. Finally, experiments demonstrate the validity of the method.     

通过CBT方法开发低热输入低飞溅CO2/MAG交流焊接系统

OTC(DAIHEN Corporation)公司新研发的CBT焊接控制法实现了GMA焊接的低飞溅和低热输入,特别是针对薄板,进一步提高了薄板的焊接性能,这对早期的传统焊接控制技术来说是很难实现的.通过调节负极占空比,交流CBT控制法能够实现改变焊接过程中的熔深和熔敷量,有效避免了薄板焊接中的烧穿和降低热变形问题.新开发的反抽起弧控制确保了起弧的成功率并有效拟制飞溅的发生.