Subcellular localization of the US3 protein kinase of herpes simplex virus type 2

One supposes that herpes simplex virus US3 gene product possessing serine/threonine protein kinase activity is a cytoplasmic enzyme. To determine its subcellular localization during viral replication we prepared an antiserum to a synthetic oligopeptide corresponding to the N-terminal region of the US3 protein of HSV type 2 strain 186. The US3 protein first appeared in the cytoplasm of infected cell at 4 h postinfection but strong fluorescence was detected in the nuclei at 8 h postinfection. At 12 h postinfection fluorescence was mainly detected in the cytoplasm, again. Further, the US3 protein expressed alone was widely distributed throughout the cell, indicating that the US3 protein by itself can be localized in the nuclei even in the absence of any other viral proteins. These observations suggest that the HSV-2 US3 protein kinase may function not only in the cytoplasm but also in the nuclei.     

Admittance-Curve-Fitting Method for Semiconductive Piezoelectric Ceramics

The admittance-curve-fitting method is proposed to determine material coefficients of semiconductive piezoelectric ceramics. In this method, the frequency dependence of admittance of a plate resonator is calculated around the resonance frequency, and the piezoelectric, elastic, and dielectric coefficients in the theoretical formula are refined to fit the observed data. The result of a simulation using four types of hypothetical ceramics with different conductivities and electromechanical coupling factors indicates that various constants determined by this method are more accurate than those by the conventional method. The fitting method is applied practically to the PZT ceramics and Bi,K-doped PZT ceramics which show semiconductivity.     

The role of the destruction box and its neighbouring lysine residues in cyclin B for anaphase ubiquitin-dependent proteolysis in fission yeast: defining the D-box receptor

Programmed proteolysis of proteins such as mitotic cyclins and Cut2/Pds1p requires a 9-residue conserved motif known as the destruction box (D-box). Strong expression of protein fragments containing destruction boxes, such as the first 70 residues of Cdc13 (N70), inhibits the growth of Schizosaccharomyces pombe at metaphase. This inhibition can be overcome either by removal of all lysine residues from N70 using site-directed mutagenesis (K0-N70) or by raising the concentration of intracellular ubiquitin. Consistent with the idea that competition for ubiquitin accounts for some of its inhibitory effects, wild-type N70 not only stabilized D-box proteins, but also Rum1 and Cdc18, which are degraded by a different pathway. The K0-N70 construct was neither polyubiquitinated nor degraded in vitro, but it blocked the growth of strains of yeast in which anaphase-promoting complex/cyclosome (APC/C) function was compromised by mutation, and specifically inhibited proteolysis of APC/C substrates in vivo. Both K0-N70 and 20-residue D-box peptides blocked polyubiquitination of other D-box-containing substrates in a cell-free ubiquitination assay system. These data suggest the existence of a D-box receptor protein that recognizes D-boxes prior to ubiquitination.     

Dielectric measurement using non-contact microwave single probe for dielectric materials

A high frequency dielectric measurement method was proposed using a non-contact probe. The microwave reflection intensity was measured for Al₂O₃ and SrTiO₃ substrates at room temperature as a function of distance between sample and probe. The difference of reflection intensity for Al₂O₃ and SrTiO₃ substrates was observed in the region where the distance of 0.2 mm between sample and probe, and it was caused from dielectric permittivities of samples. The reflection coefficient of sample was estimated in comparison with results of electromagnetic simulation. The reflection intensity for Al₂O₃ and SrTiO₃ substrates was transformed to dielectric permittivity at reflection intensity minimum point.     

Enhanced piezoelectric properties of potassium niobate single crystals with fine engineered domain configurations

Potassium niobate (KNbO₃) single crystals were grown by a top seed solution growth (TSSG) method. At first, the electric field was applied along [0 0 1]_c (cubic notification system) direction of KNbO₃ crystals to induce the engineered domain configurations into KNbO₃ crystals. Prior to domain engineering, the piezoelectric properties of [0 0 1]_c oriented KNbO₃ single-domain crystals were measured. These measured values were completely consistent with the calculated apparent d₃₁ and d₃₂. Finally, the engineered domain configurations were induced into KNbO₃ crystals. As a result, piezoelectric properties increased with decreasing domain sizes of the engineered domain configuration.     

Growth of lithium doped silver niobate single crystals and their piezoelectric properties

Lithium doped silver niobate (Ag_1−xLi_xNbO₃, 0 < x < 0.1) is one of the candidate materials for lead-free piezoelectric materials. In this study, Ag_1−xLi_xNbO₃ single crystals were successfully grown by a slow cooling method. Crystal structure was assigned to perovskite-type orthorhombic (monoclinic) phase. Dielectric properties were measured as a function of temperature. As a result, with increasing lithium contents, the phase transition at around 60 °C was shifted to lower temperature while the phase transition at around 400 °C was shifted to higher temperature. On the basis of these peak shifts, the lithium contents in Ag_1−xLi_xNbO₃ single crystals were determined. Moreover, P–E hysteresis measurement revealed that pure silver niobate crystal was weak ferroelectrics with P_r of 0.095 μC/cm² while Ag_0.9Li_0.1NbO₃ (ALN10) crystal was normal ferroelectrics with P_r of 10.68 μC/cm². About this ALN10 crystal, polling treatment was performed and finally piezoelectric properties were measured. As a result, high electromechanical coupling coefficient k₃₁ over 70% was observed.     

燃料电池用质子电解质的研究进展

目前,作为燃料电池的重要部件的质子电解质主要分为有机、有机一无机复合、无机三类.有机质子电解质接近商业化程度,但其价格昂贵,中温导电性差;复合质子电解质是以前者为基础掺杂增湿组分,使燃料电池性能有一定程度的增强;提高工作温度是解决燃料电池中催化荆CO中毒和提高燃料转化效率的有效办法,因此能在中高温环境中工作的无机质子导电材料已成为研究热点之一.     

Spectroscopic Ellipsometry of Nickel Oxide/Zinc Oxide Artificial Superlattices

Thin films of ZnO and NiO and their superlattices were made by an ion beam sputtering technique. The dielectric functions of these films were measured as a function of photon energy using a variable-angle spectroscopic ellipsometer. Artificial superlattices were formed in [(NiO)₁₂/(ZnO)₆]₁₀, [(NiO)₆/(ZnO)₄]₁₆, and [(NiO)₇/(ZnO)₈]₁₂ films, where ZnO had the rock salt structure rather than the wurtzite type of structure. The dielectric functions of these superlattices were markedly different from those of pure ZnO, NiO, and their mixtures. However, ZnO had the wurtzite type of structure in [(NiO)₁₀/(ZnO)₂₀]₄. In this film, the epitaxial relation which enables the formation of an artificial superlattice was not observed between ZnO and NiO layers, and the dielectric function could be interpreted as a simple mixture of ZnO and NiO.