Gasification of coals treated with non-aqueous solvents. 6. Catalytic steam gasification at atmospheric pressure

Nickel-catalysed steam gasification was examined for two Japanese and three German coals which had been pretreated with liquid ammonia. Reaction temperatures range from 923 to 1123 K. The greatest enhancement in reactivity by ammonia treatment and 1 wt % nickel loading was observed for Leopold coal. With this treatment, the temperature could be lowered by about 55 K to achieve the same conversion level as the original coal. The apparent activation energy decreased from 220 to 140 J/mol. The crucible swelling number decreased from $\text{1}\text{1}\text{2}$to 0. The surface of the char after gasification was examined by a scanning electron microscope. The role of the catalyst and the interaction of nickel with sulphur are discussed.     

Oxygen Configuration in the Superconductor (Hg0.7Mo0.3)Sr2(Ca1−xRx)Cu2Oz (R = Nd and Pr)

Two series of Hg-based oxides (Hg_0.7Mo_0.3)Sr₂(Ca_1?x R _x )Cu₂O _z (R = Nd and Pr, 0.2 ≤ x ≤ 0.7) have been synthesized. Electrical-resistivity measurements show that these compounds are superconductors with maximum onset T _c of 107 and 102 K for Nd- and Pr-containing samples, respectively. The neutron powder diffraction experiments on both as-prepared and O₂-annealed samples of R = Nd revealed that the O(3) site at the HgO_δ sheets are fully occupied and shifted towards the Hg/Mo site to form Mo–O bonds.     

Analysis of a 30 kbp plasmid encoding histidine decarboxylase gene in Tetragenococcus halophilus isolated from fish sauce

In order to analyze the genes related to the histamine production, a strain of histamine producing halophilic bacteria, referred to as strain H, was isolated using enrichment culture and dilution-to-extinction methods with histidine broth inoculated from the fish sauce mashes. The two Japanese fish sauce mashes used, accumulate over 1000 mg/l of histamine. Phenotypic and 16 S rRNA gene sequence analyses identified strain H as Tetragenococcus halophilus, the predominant histamine producing bacteria present during fish sauce fermentation. Genetic analyses (PCR and Southern blot) of the histamine producing strain confirmed that the strain harbored a 30 kbp plasmid (pHDC) encoding a single copy of the pyruvoyl dependent histidine decarboxylase gene (hdc). A comparison of hdcA that is a structural gene of histidine decarboxylase among strain H, Lactobacillus hilgardii 0006, L. sakei LTH2076, Oenococcus oeni 9204, T. halophilus and T. muriaticus JCM10006 (T) indicated >99% sequence similarity. The hdc gene cluster consisted of 4 ORFs, hdcP, hdcA, hdcB, and hdcRS, and were almost identical to that of L. hilgardii 0006 with 99% sequence similarity including the structural hdc spacer region. However, the approximately 500 bp regions upstream and downstream of the hdc gene were different between that of strain H and L. hilgardii 0006. The complete sequence of pHDC revealed 29,924 nucleotides including 28 ORFs, two pairs of IR (inverted repeat), similar sequence of plasmid conjugative elements, and a theta-type replicon. These results suggested that hdc could be encoded on transformable elements among lactic acid bacteria.     

Reduction of lipids in fish meal prepared from fish waste by a yeast Yarrowia lipolytica

The high lipid content in fish waste is one of the reasons why fish meal made from fish waste is commercially rated as low grade meal. Microorganisms which have the ability to reduce crude lipids from samples of minced fish in solid-state fermentation were screened and a strain of Yarrowia lipolytica showed the highest efficiency for reducing the lipids by 29%. The lipid reduction by this strain was especially affected by the ratio of surface area to the weight in the fermented mince samples and by the water content, suggesting the importance of the oxygen supply. In the fermentation with intermittent mixing during 96 h incubation, reduction efficiency for crude lipids came to 46% but that for protein was less than 1%. With the fermentation, 41.5 g of crude lipids in 1 kg of the minces were estimated to be reduced to 22.4 g, indicating increase of protein content in the final product. Furthermore, the carbonyl value which is an indicator of lipid oxidation was relatively suppressed by the fermentation. These results suggest that the fermentation can improve the quality of fish meal from fish waste which is rich of lipids.     

Ultra-wideband tellurite-based Raman fibre amplifier

The first wideband tellurite-based Raman fibre amplifier is described. The amplifier provided a 160 mn bandwidth with a gain of over 10 dB and a noise figure below 10 dB from 1490 to 1650 nm with a tellurite-based fibre only 250 m in length pumped by 4 wavelength channel LDs     

Abnormal saturation magnetization dependency on W content for Co-W thin films

A series of hexagonal close-packed (HCP) Co-W thin films were deposited by sputtering on surface oxidized silicon substrates at 300℃. A linear dependency of saturation magnetization (M_s) on W content was found up to about 9~at.~pct W, and then it underwent an increased M_s vs. W content curve as compared to the initial linear dependency. The thermal magnetization technique was used to confirm that the increased M_s behaviour is correlated to the phase separation of the Co-W thin films. The phase separation behaviour was also found to be dependent on W content and the reason was discussed in detail. Finally an interesting composition range was suggested to be about 13at.pct-17 at. pct W for the Co-W thin films, in which they exhibit much higher magnetic anisotropy energy than Co-Cr thin films and improved phase separation.     

Effect of membrane surface potential on the uptake and the inhibition of cationic compounds in rat intestinal brush-border membrane vesicles and liposomes

The effect of membrane surface potential on the uptake of tryptamine, an organic cation, by rat intestinal brush-border membrane vesicles was investigated. In the presence of an inside-negative K(+)-diffusion potential, the manner of initial uptake of tryptamine appeared to be pH-dependent and the uptake in the acidic medium was lower than that in the neutral medium. Changes in surface potential of brush-border membrane vesicles were monitored using 8-anilino-1-naphthalenesulfonic acid (ANS) and the results suggested that the membrane surface potential (negative charge on the membrane surface) decreased in the acidic medium. A good correlation was observed between the K(+)-diffusion potential-dependent uptake of tryptamine and membrane surface potential monitored by ANS at various pH levels. The uptake of tryptamine by liposomes (large unilamellar vesicles), which contained various amounts of dipalmitoylphosphatidylserine (DPPS), was also examined. The uptake of tryptamine decreased with a decrease of DPPS content in the liposomes, and was correlated with the membrane surface potential monitored by ANS. Moreover, the effect of organic cations on the uptake of tryptamine by intestinal brush-border membrane vesicles was examined. The uptake of tryptamine was inhibited by tetracaine and imipramine. The inhibitory effect of these cations was well correlated with changes in the membrane surface potential in the presence of tetracaine or imipramine. These results suggest that the K(+)-diffusion potential-dependent uptake of tryptamine by intestinal brush-border membrane vesicles is affected by membrane surface potential, and the inhibition of tryptamine uptake originates in changes in the membrane surface potential caused by the organic cations.     

Optical tap array using distributed-index planar microlens

The letter describes a novel optical tap array by using a two-dimensional array of planar microlenses. The present device is used to monitor a part of light which is transmitted through optical fibres. Planar microlenses to focus the light have been monolithically fabricated by the use of the electromigration technique; the focal length is 3 mm and NA is 0.15. The coupling efficiency of the initial device was 52% for coupling multimode graded-index fibres.