Electrical Breakdown Properties and Space Charge Formation in High Temperature Region in Ultraviolet Ray Irradiated PVC

Polyvinyl chloride (PVC) is the most popular insulating material for electric wiring instruments. However, an exothermic reaction above 150 °C may cause deterioration of the insulating properties of PVC. Therefore, it is important to clarify the heat degradation in PVC, not only to investigate the ignition of electrical wiring products but also to use electrical products safely. It is known that ultraviolet (UV) irradiation causes chemical deterioration of PVC and an increase in its conductivity. Generally, it has been thought that the electrical breakdown properties, electrical conduction, and insulating performance are affected by space charge accumulation in an insulating material. A high temperature pulsed electroacoustic (PEA) system usable up to 250 °C has been developed, and the PEA system can measure the space charge distribution and conduction current in the high temperature range simultaneously. In this investigation, the space charge distribution and conduction current were measured up to electrical breakdown in a non‐UV irradiated sample (normal PVC) and in 353 nm and 253 nm UV‐irradiated PVC samples in the range from room temperature to 200 °C in a DC electric field. In the short wavelength UV irradiated PVC sample (253 nm, 300 h), a deterioration of breakdown strength at 90 °C to 150 °C and negative packet‐like charges were observed at 60 °C and 100 °C, a positive charge accumulated in front of both the anode and cathode above 90 °C, and a higher electric field near the cathode side because the positive charge of the cathode side was greater.     

Selective detection and differentiation of subgenus B adenoviruses (types 3, 7 and 11) by polymerase chain reaction

Application of the polymerase chain reaction (PCR) method for detection of subgenus B adenoviruses (types 3, 7 and 11) was investigated. It is based on a simple (nonnested) PCR using primer pairs specific for the hexon-coding region. The PCR allowed amplification of DNA from subgenus B adenovirus prototype strains (types 3, 7 and 11) and adenovirus isolates (types 3 and 7), whereas it did not amplify DNA from subgenus A (type 31), C (types 1, 2, 5 and 6), D (types 8, 19 and 37), E (type 4) and adenovirus isolates (types 1, 2, 5 and 6). These results suggest that subgenus B adenoviruses (types 3, 7 and 11) are detectable selectively by means of PCR with primer pairs developed in this study. Amplified fragments from adenovirus types 3, 7 and 11 could be differentiated with restriction endonuclease analysis with Rsa I.     

A cathode readout gas sampling calorimeter with conductive plastic tubes

We constructed and tested a prototype gas sampling electromagnetic calorimeter of the Pb-proportional tube sandwich type. The calorimeter uses conductive plastic tubes and cathode pad readout with a tower structure which resulted in reasonable energy and spatial resolutions for electrons in the momentum range 0.5–4.0 GeV/c; $\text{σ}{}_{\mathrm{E}}\text{E =}\text{21\%}\text{(E(}\text{GeV}\text{)}\text{)}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{, σ}{}_{\mathrm{x}}\text{= 6}\text{mm}\text{(at 3 GeV}$/c). This paper describes the test and the performance studied under various conditions.     

Fodrin is a constituent of the cortical lattice in outer hair cells of the guinea pig cochlea: immunocytochemical evidence

Localization of fodrin, a membrane skeletal protein, in the outer hair cell of the guinea pig cochlea was examined by immunocytochemical techniques. By immunofluorescence microscopy, fodrin was observed in the cuticular plate, in the infracuticular network and along the lateral wall. By immunoelectron microscopy of ultrathin cryosections, labeling for fodrin along the lateral wall was localized between the cell membrane and the outermost layer of the subsurface cisternae. Furthermore, pre-embedding immunoelectron microscopy of permeabilized specimens showed that most immunogolds for fodrin were on the thin cross-linking component of the cortical lattice. The results indicate that fodrin is a constituent of the cortical lattice which is thought to play an important role in outer hair cell motility.     

Effects of Na+ and Mg2+ on the structures of supercoiled DNAs: comparison of simulations with experiments

Recent cryo-electron microscopy (cryo-EM) results suggest that sufficient NaCl concentration (> or approximately 0.1 M) and superhelix density (> or approximately-0.05) cause circular DNAs to adopt highly extended, tightly interwound configurations, in which the strands are laterally contiguous along almost their entire length. Millimolar levels of MgCl2 reportedly act synergistically with NaCl to produce similar conformations. However, Monte Carlo simulations with purely repulsive interduplex forces failed to reproduce such structures. In the present work, solution measurements of particular physical properties were performed both to characterize the effects of Na+ and Mg2+ on DNA structure and to provide quantitative tests of Monte Carlo simulations of circular DNAs. Supercoiled p30 delta DNAs in 10 mM Tris plus 0, 0.122, and 0.1 M NaCl, and 0.1 M NaCl plus 4 mM Mg2+ were examined by static and dynamic light scattering (LS and DLS), time-resolved fluorescence polarization anisotropy (FPA) of intercalated ethidium, and circular dichroism (CD) spectroscopy. Upon addition of 0.122 M NaCl, the radius of gyration (Rg) decreased substantially, which indicates that p30 delta adopts a more compact structure. This contradicts the cryo-EM studies, where molecular extension and Rg both increase upon adding 0.1 M NaCl. In 0.1 M NaCl, the torsion constant measured by FPA is practically invariant to superhelix density, and the plateau diffusion coefficient at large scattering vector (Dplat) is likewise nearly the same at both relaxed and native superhelix densities. Such invariance is difficult to reconcile with any transition from relaxed circles to tightly interwound structures with laterally contiguous strands. Metropolis Monte Carlo simulations were performed to generate canonically distributed sets of structures, from which average Do values and scattered intensity ratios, [symbol: see text]I (zero) [symbol: see text]/[symbol: see text] l(k) [symbol: see text], were calculated. Agreement between simulations and experiments in regard to [symbol: see text] I(O) [symbol: see text] /[symbol: see text] I(k) [symbol: see text], D(zero) and the supercoiling free energy, delta Gsc (delta l), is remarkably good for the most extensively studied p30 delta samples. The simulated structures exhibit no sign of very tight interwinding with extensive lateral contacts, but instead exhibit most probable superhelix diameters of 85 to 90 A. When 4 mM Mg2+ was added to native supercoiled p30 delta in 0.1 M NaCl, Rg decreased, D(zero) increased, and the longest internal relaxation rate (1/tau 2(zero)) increased, all of which indicate a further overall contraction of the molecular envelope. The torsion constant exhibited a slight increase that is hardly statistically significant. In this case, agreement between the simulations and experiments was only semi-quantitative for most samples investigated, although the predicted contraction was exhibited by all five samples of p30 delta and one of pBR322 DNA. The simulated structures in 0.1 M NaCl plus 4 mM Mg2+ again showed no sign of extensive lateral contacts. A plausible explanation is proposed for the highly extended, tightly interwound structures seen in cryo-EM, and explicitly tested by Monte Carlo simulations of a 1000 bp circular DNA at +25 and -50 degrees C. Structures identical to those seen in cryo-EM are in fact the equilibrium structures in the simulations at -50 degrees C, and the estimated time for equilibration (2.3 x 10(-6) second) is much smaller than the estimated time for vitrification (1 x 10(-4) second).     

Arterial embalming method of the cadaver and its application to research

Ever since 1974, the cadaver has been embalmed by the arterial embalming method, using pre-embalming fluid with blood clot disperser and cell conditioner for the removal of blood clots and drainage of blood, at the Department of Anatomy of the Kawasaki Medical School. According to this method, the cadavers are always very well fixed so that they can be used for not only anatomical dissection but also research for the vascular system by vasography, kinematics of the joint and other histologic examinations. In this report we have described our embalming procedure concretely and its application to research.     

Effect of the Treatment Temperature on the Surface Drying Set of Sugi Boxed-Heart Square Timber

High-temperature and controlled humidity treatment before drying has proven to be highly effective in preventing surface checks by forming drying sets in the surface layer of boxed-heart square timber in Japan. In this study, we examined the differences of the surface drying sets on sugi timber under different treatment temperatures. As a result, the width of a surface check after drying was much smaller at a treatment temperature of 120°C than at 80°C, and this indicates that the drying set with 120°C treatment would be larger than that with 80°C treatment. Also we observed that treatment temperature had a greater effect on the drying set as the drying advanced.     

Inhibition of resistance to hemopoietic allo-grafts in granulocyte colony-stimulating factor transgenic mice

The measurements of diphenylhexatriene (DPH) and trimethylammonium diphenylhexatriene (TMA-DPH) fluorescence anisotropy in egg yolk lecithin (EYL) and of DPH anisotropy in dipalmitoylphosphatidylcholine (DPPC) liposomes containing different concentrations of oxidized and reduced ubiquinone (UQ) and plastoquinone (PQ) homologues have been performed. All the oxidized UQ homologues strongly induced ordering of EYL membrane structure, whereas in DPPC liposomes, above the phase transition temperature, the most pronounced effect showed UQ-4. PQ-2 and PQ-9 were less effective than the corresponding ubiquinones in this respect. The reduced forms of UQ and PQ homologues increased the order of membrane lipids to a smaller extent than the corresponding quinones both in the interior of the membrane and closer to its surface. Nevertheless, the investigated prenylquinols showed stronger increase in the membrane order than alpha-tocopherol or alpha-tocopherol acetate, which could be connected with binding of prenylquinol head groups to phospholipid molecules by hydrogen bonds. The strong ordering influence of ubiquinones on the membrane structure was attributed to methoxyl groups of the UQ quinone rings.