Electrical and Thermal Conductivity and Conduction Mechanism of Ge<Subscript>2</Subscript>Sb<Subscript>2</Subscript>Te<Subscript>5</Subscript> Alloy

Ge₂Sb₂Te₅ alloy has drawn much attention due to its application in phase-change random-access memory and potential as a thermoelectric material. Electrical and thermal conductivity are important material properties in both applications. The aim of this work is to investigate the temperature dependence of the electrical and thermal conductivity of Ge₂Sb₂Te₅ alloy and discuss the thermal conduction mechanism. The electrical resistivity and thermal conductivity of Ge₂Sb₂Te₅ alloy were measured from room temperature to 823 K by four-terminal and hot-strip method, respectively. With increasing temperature, the electrical resistivity increased while the thermal conductivity first decreased up to about 600 K then increased. The electronic component of the thermal conductivity was calculated from the Wiedemann–Franz law using the resistivity results. At room temperature, Ge₂Sb₂Te₅ alloy has large electronic thermal conductivity and low lattice thermal conductivity. Bipolar diffusion contributes more to the thermal conductivity with increasing temperature. The special crystallographic structure of Ge₂Sb₂Te₅ alloy accounts for the thermal conduction mechanism.     

Photovoltaic display module in a mobile GPS

We have developed a mobile global positioning system (GPS) that operates on just photovoltaic (PV) cells. The system receives wireless signals from satellites and shows one's present location accurately on a map without the need for a battery. A PV display module, which combines a transparent LCD with a-Si PV cells and has a power generation function, is added to ordinary PV cells to increase the total amount of power generated. The PV display module enables 40% more power generation than a system without the module.     

Jitter Accumulation for Periodic Pattern Signals

It is important to accurately evaluate and reduce jitter accumulation in long-haul digital repeatered lines. Jitter accumulation caused by random pattern signals has already been analyzed. However, periodic pattern signals such as pseudorandom signals are usually used to measure jitter accumulation. This paper describes the difference between the jitter accumulation for both signals and the necessary conditions to accurately estimate jitter accumulation for random pattern signals by using periodic pattern signals. First, it is shown theoretically that systematic jitter for periodic signals saturates, showing a ripple pattern. The limit of increase is determined by the ratio of tank bandwidth and pattern repetition frequency. Up to a certain number of regenerators determined by the ratio, systematic jitter increases in rough proportion to thesqrt{N}slope. It is also shown that the equation to estimate random pattern jitter accumulation is determined by the measured value for periodic pattern signals. Second, jitter characteristics are simulated by optical signal circulating experiments. The results are in agreement with the analysis. In addition, the reduction effects on periodic signal jitter accumulation caused by timing signal delay and nonlinearity of the limiter in the timing circuit are shown.     

Analysis of phenmedipham in agricultural products by HPLC

An analytical method was developed for the determination of phenmedipham (PM) in agricultural products using reversed-phase high-performance liquid chromatography with UV detection. A sample was extracted with acetonitrile, and the acetonitrile layer was separated by salting-out. The acetonitrile phase was isolated and evaporated. The extract was dissolved in diethyl ether-hexane (1 : 1), and then cleaned up on a Florisil column. The column was washed with diethyl ether-hexane (1 : 1), and PM was eluted with acetone-hexane (3 : 7), and the eluate was evaporated. The residue was dissolved in acetone-hexane (2 : 8), and the sample solution was cleaned up on SAX/PSA cartridge. The SAX/PSA cartridge was washed with acetone-hexane (2 : 8), and PM was eluted with acetone-hexane (3 : 7). If required, the eluate of the Florisil column was cleaned up with SAX/PSA and ENVI-Carb/ NH2 cartridges. The SAX/PSA cartridge was washed with acetone-hexane (2 : 8), and connected to be ENVI-Carb/NH2 cartridge. The cartridges were washed with acetone-hexane (3 : 7), and then the SAX/PSA cartridge was removed. PM was eluted with acetonitrile-toluene (3 : 1) from the ENVI-Carb/NH2 cartridge. PM in the eluate was separated isocratically on an ODS column (4.6 mm i.d. x 150 mm, 5 microm) using acetonitrile-water (6 : 4) as a mobile phase (flow-rate 1.0 mL/min, temp. 40 degrees C), with monitoring at 235 nm. The calibration curve was linear from 0.005 microg/mL to 10 microg/mL of PM. The recoveries of PM from eight kinds of agricultural products spiked at levels of 0.1 and 0.02 microg/g were 80.8-98.7%. The determination limit was 0.01 microg/g.     

Identification of HLA-A24-restricted epitopes with high affinities to Hsp70 using peptide arrays

Heat shock protein 70 (Hsp70) family members are known as facilitators of immune responses by interacting with receptors on antigen-presenting cells leading to Hsp70-peptide uptake and antigen cross priming. Here, identification of human leukocyte antigen (HLA)-A24-restricted epitopes was achieved using peptide arrays for evaluation of their affinities to Hsp70 and HLA-A24 binding prediction tools. Using Hsp70 as the model antigen, the GYPVTNAVI and VFQHGKVEI peptides were identified as antigens. These peptides actually bound to HLA-A24 in the stabilization assay using T2-A*2402 cells, and induced a strong peptide-reactive cytotoxic T lymphocyte response in HLA-A24 transgenic mice after vaccination.     

Phytoextraction by a high-Cd-accumulating rice: reduction of Cd content of soybean seeds

Soybeans (Glycine max (L) Merr.) are the major summer crop grown in Japanese upland fields (characterized by aerobic soil) that have been converted from paddies. To evaluate the effect of phytoextraction by rice on the seed cadmium (Cd) content of soybeans grown subsequently, we grew Milyang 23, a high-Cd-accumulating rice cultivar, and then grew soybeans in three paddy soils contaminated with moderate Cd concentrations (2.50-4.27 mg Cd kg(-1)). The rice accumulated 7-14% of the total soil Cd in its shoots. The soybean seed Cd contents were 24-46% less than those grown on control soils. Phytoextraction by Milyang 23 rice is thus a promising remediation method for reducing seed Cd contents of soybeans grown on paddy soils under aerobic soil conditions.     

Immobilization of alkaline phosphatase on magnetic particles by site-specific and covalent cross-linking catalyzed by microbial transglutaminase

Bacterial alkaline phosphatase (BAP) was site-specifically and covalently immobilized on magnetic particles (MPs) using the enzymatic reaction of microbial transglutaminase (MTG). Immobilization efficiency was affected by the chemical surface treatment of MPs and immobilized BAP exhibited more than 90% of the initial activity after 10 rounds of recycling.     

Myosin is solubilized in a neutral and low ionic strength solution containing l-histidine

Myosin, one of the major myofibrillar proteins, is insoluble at low and physiological ionic strength and soluble at high ionic strength. In this study, the behavior and morphology of myosin solubilized in a low ionic strength solution containing l-histidine (l-His) was investigated. More than 80% of myosin was solubilized in a low ionic strength solution with dialysis against a solution containing 1 mM KCl and 5 mM l-His. Transmission electron microscopy with rotary shadowing demonstrated that the rod of myosin in a low ionic strength solution containing l-His is longer than that of myosin in a high ionic strength solution. The elongation of the myosin rod in a low ionic strength solution containing l-His would inhibit the formation of a filament, resulting in the solubilization of myosin.