Reaction products of α-tocopherol with methyl linoleate-peroxyl radicals

α-Tocopherol was reacted with methyl linoleateperoxyl radicals at 37°C. The peroxyl radicals were generated by the reaction of methyl linoleate with a free radical initiator, 2,2′-azobis(2,4-dimethylvaleronitrile). The primary products of α-tocopherol with methyl linoleate-peroxyl radicals were isolated by reversephase and normal-phase high performance liquid chromatography (HPLC), and their structures were characterized by ultraviolet (UV), infrared (IR),¹H and¹³C nuclear magnetic resonance (NMR) and mass spectrometry (MS). There were four stereoisomers of methyl 13-(8a-peroxy-α-tocopherone)-9(Z),11(E)-octadecadienoate and four stereoisomers of methyl9-(8a-peroxy-α-tocopherone)-10(E),12(Z)-octadecadienoate.     

Effects of additives on sintering of CVD-MgO powders

The effects of a large number of sintering aids for the densification of magnesia were examined. Al₂O₃, BaO, Fe₂O₃, P₂O₅, SiO₂, TiO₂, Y₂O₃ and ZrO₂ are effective for the sintering of CVD-MgO powders at low doping levels. The effects of TiO₂ and ZrO₂ are significant. Heavy doping is harmful for densification. The eight oxides above are also effective for the sintering of seawater MgO, but the degree of effectiveness is smaller than for CVD-MgO. In the doping of BaO, P₂O₅, SiO₂ and TiO₂, which form eutectic liquids with MgO below 1600°C, there is an optimum firing temperature for densification.

Vickers hardness of doped MgO is proportional to the relative density and is unaffected by doping. Corrosion resistance of MgO ceramics for liquid PbO is also unaffected by dopants, except for P₂O₅.     

Production of eicosapentaenoic acid by a bacterium isolated from mackerel intestines

Optimization of culture conditions for the growth rate, 5,8,11,14,17-cis-Eicosapentaenoic acid (EPA) content and EPA productivity of a bacterium isolated from Pacific mackerel intestines was investigated by use of a culture medium containing 1.00 wt% peptone and 0.50 wt% yeast extract in an artificial sea water (ASW). Cultivation temperature affected the growth rate and cellular EPA content of the bacterium. The cellular EPA content at 8°C was as great as 16.8 mg/g of dry cells, which was more than two times greater than that at 25°C (7.3 mg/g of dry cells), although the growth rate showed a maximum at 25°C. Both the yield of bacterial cells and the cellular EPA content at 25°C reached maximum values when the pH of the culture medium was nearly 7.0 and when the concentration of ASW was 100% (v/v). Under optimum culture conditions [25°C pH 7.0 and 100% (v/v) ASW], the amount of EPA accumulated in the cellular lipids reached 45.6 mg/L of culture broth after 8 hr.     

Side-milling technique of preparing device cross-sections for electron holography based on a focused ion beam micro-sampling system

A new milling technique based on a focused ion beam (FIB) microsampling system is proposed to avoid the curtaining effect, commonly occurring in other FIB milling methods, in order to obtain a crosssectional device specimen with uniform thickness can be obtained for electron holographic observation.     

Thermoelectric Properties of Rare Earth-Doped SrTiO3 Nanocubes

A giant Seebeck coefficient of ?890 μV/K at 500 °C has been observed in Y_0.2Sr_0.8TiO₃ prepared using nanocubes. Doping rare earth elements, RE, has revealed that small RE is effective to enhance the Seebeck coefficient. Through soft mode observations by Raman spectroscopy and structural calculations based on density functional theory, it has been found that the breakdown of inversion symmetry of the perovskite structure near the surface of nanocubes can be recovered by doping with small RE. Because the dielectric constant is strongly related to the surface structure in this compound, we suggest that RE doping modulates the potential barrier at the grain boundary, resulting in a pronounced energy filtering effect in Y doped SrTiO₃.     

Measurement of RF Transmission Mode in ITER Relevant EC H&;CD Transmission Line

The preliminary results of mode measurement in the ITER relevant 40 m long transmission test line composed from 63.5 mm diameter corrugated waveguides and miter bends are presented. The field patterns were measured by taking temperature profiles on a paper screen placed in front of the waveguide end using an infrared imaging camera. The complex electric field at the waveguide end was retrieved from the measured temperature profiles. As a result, the transmission power includes 87% of HE₁₁ mode and 6% of LP₁₁ odd (HE₂₁+TE₀₁) mode and small ratios of other modes. The mode content had small dependence on length of the transmission line. This result indicated that the higher order mode content generated at the input of the transmission line is conserved and propagated through the transmission line. This suggests that the initial RF coupling to the waveguide is critical since it affects the launcher efficiency.     

Subcellular localization of fructosyl amino acid oxidases in peroxisomes of Aspergillus terreus and Penicillium janthinellum

Fructosyl amino acid oxidase (FAOD) is the enzyme catalyzing the oxidative deglycation of Amadori compounds, such as fructosyl amino acids, yielding the corresponding amino acids, glucosone, and H(2)O(2). In a previous report, we determined the primary structures of cDNAs coding for FAODs from two fungal strains Aspergillus terreus AP1 and Penicillium janthinellum and we found that both fungal FAODs included the putative peroxisome targeting signal 1 (PTS1) at the carboxyl terminal (Yoshida, N. et al., Eur. J. Biochem., 242, 499-505, 1996). In this study, we determined the intracellular localization of FAODs in these two fungi. Subcellular fractionation experiments and immuno-electronmicroscopic observations, together with the previous findings indicated that the FAODs were localized in peroxisomes of A. terreus AP1 and P. janthinellum. These FAODs were also found to belong to a new member of "peroxisomal sarcosine oxidase family protein" in eucaryotic cells.     

A novel hemiacetal dehydrogenase activity involved in ethyl acetate synthesis in Candida utilis

Acetate ester synthesis was studied in vitro with the ethyl acetate-producing yeast Candida utilis. The level of enzyme activity observed for the NAD+-dependent hemiacetal dehydrogenase acting on hemiacetal, which was produced non-enzymatically from an alcohol and an aldehyde, was much greater than that for the other enzyme involved in ester synthesis, alcohol acetyltransferase. The level of ethyl acetate synthesis in vivo approximately paralleled the hemiacetal dehydrogenase (HADH) activity. The results suggest that the main pathway for ethyl acetate synthesis in C. utilis involves a novel hemiacetal dehydrogenase activity.     

Deep-submicrometer BiCMOS circuit technology for sub-10-ns ECL 4-MbDRAM's

A 0.3-μm sub-10-ns ECL 4-Mb BiCMOS DRAM design is described. The results obtained are: (1) a V_cc connection limiter with a BiCMOS output circuit is chosen due to ease of design, excellent device reliability and layout area; (2) a mostly CMOS periphery with a specific bipolar use provides better performances at high speed and low power; (3) the direct sensing scheme of a single-stage MOS preamplifier combined with a bipolar main amplifier offers high speed; and (4) the strict control of MOS transistor parameters has been proven to be more important in obtaining high speed DRAMs, based on the 4-Mb design     

Metal Single-Atom Cocatalyst on Carbon Nitride for the Photocatalytic Hydrogen Evolution Reaction: Effects of Metal Species

Single-atom (SA) catalysts exhibit high activity in various reactions because there are no inactive internal atoms. Accordingly, SA cocatalysts are also an active research fields regarding photocatalytic hydrogen (H₂) evolution which can be generated by abundant water and sunlight. Herein, it is investigated whether 10 transition metal elements can work as an SA on graphitic carbon nitride (g-C₃N₄; i.e., gCN), a promising visible-light-driven photocatalyst. A method is established to prepare SA-loaded gCN at high loadings (weight of ≈3 wt.% for Cu, Ni, Pd, Pt, Rh, and Ru) by modulating the photoreduction power. Regarding Au and Ag, SAs are formed with difficulty without aggregation because of the low binding energy between gCN and the SA. An evaluation of the photocatalytic H₂-evolution activity of the prepared metal SA-loaded gCN reveals that Pd, Pt, and Rh SA-loaded gCN exhibits relatively high H₂-evolution efficiency per SA. Transient absorption spectroscopy and electrochemical measurements reveal the following: i) Pd SA-loaded gCN exhibits a particularly suitable electronic structure for proton adsorption and ii) therefore they exhibit the highest H₂-evolution efficiency per SA than other metal SA-loaded gCN. Finally, the 8.6 times higher H₂-evolution rate per active site of Pd SA is achieved than that of Pd-nanoparticles cocatalyst.