Thermomagnetic Effects in High-Mobility PbTe Films

The narrow-gap compound semiconductor PbTe has high Hall mobility. The Fermi surface at the L-point in the Brillouin zone has large anisotropy. In this work, we measured thermomagnetic effects in PbTe thin films to confirm anisotropy of the Nernst coefficient A _Ne and show Nernst mobility from the ratio of A _Ne and the Seebeck coefficient S: μ _Ne = A _Ne/S. Angular dependences of the Nernst voltage show that A _Ne is independent of the angle between the temperature gradient and the magnetic field, because of the high L-point symmetry. The calculated Nernst mobility was compared with the Hall mobility. Because the former is smaller, the Mott equation cannot explain the Seebeck coefficient at room temperature.     

Analysis for microbial contamination in production of Japanese-style confectionery "Monaka"

Food hygiene in Japanese-style confectionery factories is hard to practice because the businesses are small. In a supporting system of voluntary-based hygienic management in this field, we microbiologically investigated the production processes of "Monaka" in a workshop in Tokyo. We microbiologically assessed the processing environments as well as the products in the workshop, then proposed some improvements in the production of the confectionery. After the improvements, microbial contamination of the processing environments was reduced and no microbial contamination was found in the sugared bean, or "An" produced, though the product "Monaka" was still contaminated, especially by molds. It was clarified that the molds came from contaminated baked wheat shells, or "Kawa" and further that the wheat shells were contaminated by molds during storage.     

Urolithiasis associated with Crohn's disease: a case report

We report a case of urolithiasis caused by surgical treatment for Crohn's disease. A 28-year-old woman was referred to our department for further examination of renal stones from the medical department in September, 1995. She suffered from Crohn's disease and had a history of jejuno-ileal resection because of perforation of the ileum in 1988. Radiographs revealed multiple bilateral renal stones, and the urine oxalate concentration was elevated. She was treated with extracorporeal shock wave lithotripsy and the administration of sodium bicarbonate and citrate, but these treatments did not prevent recurrence and enlargement of stones. Renal function was gradually worsened and we performed transurethral lithotomy and percutaneous nephrolithotripsy. The stones were mainly composed of oxalate calcium monohydrate. A renal biopsy was performed at the operation, showing deposition of crystals in almost all renal tubules. Diet therapy (low oxalate and low fat) and the administration of sodium bicarbonate and citrate were performed strictly and recurrence was not recognized 10 months after complete removal of the stones.     

Analysis of the mechanism of trophoblast infiltration

Thymidylate synthase plays a central role in the biosynthesis of thymidylate, an essential precursor for DNA biosynthesis. In addition to its role in catalysis and cellular metabolism, it is now appreciated that thymidylate synthase functions as an RNA binding protein. Specifically, thymidylate synthase binds with high affinity to its own mRNA, resulting in translational repression. An extensive series of experiments has been performed to elucidate the molecular elements underlying the interaction between thymidylate synthase and its own mRNA. In addition to characterization of the underlying cis- and trans-acting elements, recent studies have shown that thymidylate synthase has the capacity to bind specifically to other cellular RNA species. While the biological significance of these other RNA/thymidylate synthase interactions remains to be defined, this work suggests a potential role for TS in coordinately regulating several critical aspects of cellular metabolism.     

Tracheal transplantation for carinal reconstruction in dogs

Subcellular localisation of xanthine oxidoreductase (XOR) was determined by indirect immunofluorescence using confocal microscopy in human endothelial and epithelial cell lines and in primary cultures of human umbilical vein endothelial cells. XOR was diffusely distributed throughout the cytoplasm but with higher intensity in the perinuclear region. In non-permeabilised cells, XOR was clearly seen to be asymmetrically located on the outer surfaces, showing, in many cases, a higher intensity on those faces apposed by closely neighbouring cells. Such specific distribution suggests a functional role for the enzyme in cell-cell interactions, possibly involving signalling via reactive oxygen species.     

Dielectric spectroscopy of metal nanoparticle doped liquid crystal displays exhibiting frequency modulation response

Twisted nematic liquid crystal displays (TN-LCDs), doped with the nanoparticles of metal, such as Pd, Ag, or Ag-Pd, which are protected with ligand molecules, such as nematic liquid crystal, exhibit a frequency modulation (FM) electro-optical (EO) response with short response time of milliseconds (ms) or sub-ms order together with the ordinary rms voltage response. These devices are called FM/AM-TN-LCDs; they are distinct from the ordinary LCDs featured by the amplitude modulation (AM) response. The phenomena of the FM/AM LCDs may be attributed to the dielectric dispersion of a heterogeneous dielectric medium known as the Maxwell-Wagner effect. It is experimentally shown that the frequency range spreads from several tens hertz to several tens kilohertz and the spectrum is more or less centered about the dielectric relaxation frequency. We formulated a theory based on an equivalent circuit model to evaluate the dielectric relaxation frequency and the dielectric strengths; and we succeeded in explaining the dependence of the dielectric relaxation frequency on the concentration of nanoparticles and the their dielectric and electrical properties, whereas conventional theories based on electromagnetic theory are unable to explain this concentration dependence. This paper reports on the experimental results of the EO effects and the dielectric spectroscopy including the dielectric relaxation times and the dielectric strengths of nematic liquid crystal, 5CB (4-pentyl-4'-cyanobiphenyl), doped with the metal nanoparticles of I'd alone and Ag-Pd composite; and discusses how the observed dielectric relaxation frequency or dielectric relaxation time depend on the concentration of the doped nanoparticles and also their electrical and dielectric properties.     

Conventional Fabrication Method for TCNQ Radical Anion Salts Molecular Wires

NMP-TCNQ (NMP=N-methylphenazinium, TCNQ=7,7,8,8-tetracyanoquinodimethane) and (NEt₄)TCNQ gave molecular wires on a glass substrate by recrystallization from the acetone solution coexistence with the substrate. The width of the wires largely depends on the evaporation ratio of the solvent through recrystallization. When evaporating ratio of NMP-TCNQ solution was 167 μl/min, the width was minimized to 35 nm. Comparison of the IR spectra and XRD patterns with the corresponding single crystals clearly indicates that these wires have same crystallinity as the single crystals.     

Identification of S100b protein as copper-binding protein and its suppression of copper-induced cell damage

We have isolated from bovine brain a protein with a high capacity to inhibit the copper ion-catalyzed oxidation of L-ascorbate and identified it as S100b protein, an EF-hand calcium-binding protein, by sequencing its proteolytic peptides. Copper binding studies showed that this protein has four copper-binding sites per dimeric protein molecule with a dissociation constant of 0.46 microM and that in the presence of L-ascorbate, copper ions bind to a total of six binding sites with a great increase in affinity. Furthermore, we examined whether S100b protein can prevent copper-induced cell damage. Bovine S100b protein was found to suppress dose-dependently the hemolysis of mouse erythrocytes induced by CuCl2. We transformed Escherichia coli cells with pGEX-5X-3 vector containing a cDNA for rat S100b protein, so that this protein could be expressed as a fusion protein with glutathione S-transferase. The transformed cells were demonstrated to be markedly resistant to a treatment with CuCl2 plus H2O2 as compared with the control cells expressing glutathione S-transferase alone. These results indicate that S100b protein does suppress oxidative cell damage by sequestering copper ions.