Characterization of plasma membrane proton-ATPase from salt-tolerant yeast Zygosaccharomyces rouxii cells

Plasma membrane was isolated from the salt-tolerant yeast Zygosaccharomyces rouxii and from Saccharomyces cerevisiae. The ATPase in the plasma membrane of Z. rouxii cells was a typical proton-ATPase as judged by testing with various ATPase inhibitors. There were slight differences in the pH optima of activities and in the sensitivity to sodium chloride (NaCl) and potassium chloride (KCl) of the ATPase from Z. rouxii and S. cerevisiae. The specific ATPase activity from Z. rouxii was higher in cells grown in a medium containing 2 _M-NaCl than in those not containing NaCl. No in vivo activation by incubation with glucose was observed in Z. rouxii cells and the specific ATPase activity was independent of the growth phase, unlike S. cerevisiae cells.     

The influence of mash pre-aging on the development of the flavour-active compound, 4-hydroxy-2(or5)-ethyl-5(or2)-methyl-3(2H)-furanone (HEMF), during soy sauce fermentation

Inoculation of Zygosaccharomyces rouxii into a soy sauce mash free from lactic acid bacteria at 10⁶ cells mL⁻¹ resulted in the formation of the flavour-active compound HEMF over a number of days at 30°C. Delays in inoculation up to 14 days after production of the mash greatly increased the amount of HEMF formed and under some conditions concentrations in the commercial range were achieved without addition of any other microorganisms.     

600 MHz optical signal transmission at the 3 ?m band using a fluoride optical fibre and a superconducting detector

We have demonstrated operation of a transmission system at the 3 ?m band. The system consists of a fluoride optical fibre, a superconducting BaPb1?xBixO3 (BPB) detector and a semiconductor Pb-salt diode laser. The low-level optical signal transmitted through the fibre is detected by the BPB detector up to 600 MHz. The observed results suggest that the BPB detector is suitable for use in infra-red optical transmission.     

Reactive carbon black having isocyanate or acyl azide group

Summary Introduction of isocyanate (NCO) group onto carbon black surface was achieved by the treatment of carbon black with toluene-2,4-diisocyanate. In addition, carbon black having acyl azide (CON₃) group, a precursor of NCO group, was prepared by the reaction of COCl or COOCOOC₂H₅ group on carbon black with NaN₃. The CON₃ group on carbon black was relatively stable at below 20°C but readily decomposed to NCO group by heating (Curtius rearrangement). By the reation of NCO group on carbon black with hydroxyl group of polymers, such as polypropylene glycol, polyethylene glycol, and polyvinyl alcohol, these polymers were found to be grafted onto carbon black.     

Thermoelectric Properties of Ca3Co4-x Ga x O9+δ Prepared by Thermal Hydro-decomposition

The polycrystalline samples of Ca₃Co_4-x Ga _x O_9+δ (0 ≤ x ≤ 0.15) were prepared by a simple thermal hydro-decomposition method. The high density ceramics were fabricated using a spark plasma sintering technique. The crystal structure of calcined powders was characterized by x-ray diffraction. The single phase of Ca₃Co_4-x Ga _x O_9+δ was obtained. The scanning electron micrograph illustrated the grain alignment perpendicular to the direction of the pressure in the sintering process. The evidence from x-ray absorption near edge spectra were used to confirm the oxidation state of the Ga dopant. The thermoelectric properties of the misfit-layered of Ca₃Co_4-x Ga _x O_9+δ were investigated. Seebeck coefficient tended to decrease with increasing Ga content due to the hole-doping effect. The electrical resistivity and thermal conductivity were monotonically decreased with increasing Ga content. The Ga doping of x = 0.15 showed the highest power factor of 3.99 × 10^-4 W/mK² at 1,023 K and the lowest thermal conductivity of 1.45 W/mK at 1,073 K. This resulted in the highest ZT of 0.29 at 1,073 K. From the optical absorption spectra, the electronic structure near the Fermi level show no significant change with Ga doping.     

Surface structure and visible light photocatalytic activity of titanium–calcium hydroxyapatite modified with Cr(III)

The synthetic titanium–calcium hydroxyapatite (Ti–CaHap) particles were treated with different concentrations of aqueous Cr(NO₃)₃·9H₂O solution and the materials obtained were characterized by a variety of conventional techniques. The crystal structure and particle morphology of Ti–CaHap were essentially not altered by treating with Cr(III) solution. With increasing the Cr(III) concentration, the amount of Cr(III) in the products was increased and that of Ca(II) was decreased. XPS results revealed that the surface state of Cr of Ti–CaHap was trivalent. These facts allow us to infer that the Cr(III) was doped by substitution of surface Ca(II) of Ti–CaHap. Besides, IR results proved that increasing the Cr(III) concentration developed the surface Cr–OH band while the surface Ti–OH and P–OH bands of Ti–CaHap vanished. This imply that the formation of surface P–O-Cr(OH)₂ and Ti–O–Cr(OH)₂ groups, resulting the Cr(OH)₃-like layer on the surface of Ti–CaHap particles. The Cr(III)-doped Ti–CaHap possessed the absorption peaks at 446 and 623 nm in vis range in addition to the UV absorption of charge transfer transition of O^2? → Ti⁴⁺. The vis absorption peaks developed on raising the Cr(III) concentration. The photocatalytic decomposition of acetaldehyde into CO₂ over Cr(III)-doped Ti–CaHap was detected under vis irradiation and the activity was lowered by the formation of Cr(OH)₃-like layer on the particle surface.     

Nano-strip grating lines self-organized by a high speed scanning CW laser

After a laser annealing experiment on Si wafer, we found an asymmetric sheet resistance on the surface of the wafer. Periodic nano-strip grating lines (nano-SGLs) were self-organized along the trace of one-time scanning of the continuous wave (CW) laser. Depending on laser power, the nano-trench formed with a period ranging from 500 to 800 nm with a flat trough between trench structures. This simple method of combining the scanning laser with high scanning speed of 300 m min(-1) promises a large area of nanostructure fabrication with a high output. As a demonstration of the versatile method, concentric circles were drawn on silicon substrate rotated by a personal computer (PC) cooling fan. Even with such a simple system, the nano-SGL showed iridescence from the concentric circles.     

Potential of renewable energy sources and its applications in Yakushima Island

A study was carried out to see if the potential of renewable energy sources other than hy droelectric power, such as wind, photovoltaic, solar thermal, biomass and waste energy sources, can meet the current energy consumption in Yakushima. The current electricity consumption can be covered by wind and photovoltaic energy sources. The total potential of wind and photovoltaic energy sources is 5.4 times as much as the current electricity consumption. LP gas and kerosene can be replaced by solar thermal and biogas energy. The potential of plant biomass and municipal waste is not sufficient (approximately one third) to cover the rest of the fossil fuels (gasoline, diesel oil and heavy oil). Also, plant biomass and municipal waste must be converted into fluid form. This shortage can be covered by the po tential of wind and photovoltaic energy sources. We also investigated the possibility of tourism expansion using the potential of wind and photovoltaic energy sources. Taking into account three types of capacity (energy, accommodation and transportation), Yakushima can accept approximately four times as many tourists as the current number of tourists.     

Thermal conductivity of near-stoichiometric (U, Ce)C and (U, Pu, Ce)C solid solutions

The thermal conductivities of near-stoichiometric (U, Ce)C and (U, Pu, Ce)C solid solutions containing CeC up to 10 mol% were determined in the temperature range from 740 to 1600 K by the laser flash method. The thermal conductivity decreased with the cerium content in the solid solutions. The electrical resistivities were also measured for the purpose of analyzing the heat conduction mechanism. It was found that the decrease of electronic heat conduction caused by the addition of cerium resulted in decreasing the thermal conductivities of (U, Ce)C and (U, Pu, Ce)C compared with UC and (U, Pu)C.