THE EXTRACTION OF NEPTUNIUM(V) BY METHYLTRIOCTYLAMMONIUM CHLORIDE AND 1-PHENYL-3-METHYL-4-BENZOYL-5-PYRAZOLONE

The synergistic effect of methyltrioctylammonium chloride (QCI) on the extraction of Np(V) by 1-phenyl-3-methyl-4-benzoyl-pyrazolone(HP) in benzene is studied over the pH range 2-6. This system extracts Np(V) better than any previously reported. The interaction of the extractants and monomer-dimer equilibria affect the distribution behavior of Np(V) in a complicated manner. Analysis of the results suggests that NpO₂ ⁺ (M⁺) is extracted as mixed dimers, (QMP₂QCl)_o and (QMP₂QP)_o.     

Deterioration of diacylglycerol‐ and triacylglycerol‐rich oils during frying of potatoes

The stabilities of a commercial diacylglycerol‐rich oil (DAG) and a salad oil (TAG) that had been prepared from a mixture of rapeseed and soybean oils were compared while frying potatoes at 180 °C for 3 h. The representative chemical and physical characteristics of the oils were assessed before and after frying, together with the amount of volatile aldehydes in the exhaust of frying. Among the deterioration indications, the carbonyl value, polymer content, and residual polyunsaturated fatty acid content were similar and not significantly different between the TAG and DAG. On the other hand, the characteristics relating to free fatty acids, i.e. the acid value and emission of chemiluminescence at 100 °C, were greater and the smoke and flash points were lower in the DAG than in the TAG. An irritating odor was generated from the DAG after 1 h of frying and got stronger as frying continued. These results suggested that DAG more easily forms free fatty acids under frying conditions than TAG.     

Poly(pyridine-2,5-diyl)–CuCl2 catalyst for synthesis of dimethyl carbonate by oxidative carbonylation of methanol: catalytic activity and corrosion influence

A -conjugated polymer, poly(pyridine-2,5-diyl) (PPy) was investigated as a support for CuCl₂ in the synthesis of dimethyl carbonate by oxidative carbonylation of methanol. The PPy–CuCl₂ adduct had high catalytic activity which was comparable to that of the homogeneous CuCl₂ catalyst. The adduct caused corrosion of stainless-steel vessels only to minor extent, compared with the homogeneous CuCl₂ catalyst. This PPy–CuCl₂ catalyst was easily recycled by filtration and showed a similar catalytic activity in the third time use. The presence of the -conjugated system in PPy, through which electrons can move, may bring about the high catalytic activity for the oxidative carbonylation of methanol, which involves Cu(II)/Cu(I) redox processes.     

Photoanodic response of iron oxide electrode in aqueous solution and its application to Pb removal under visible light irradiation

The iron oxide electrode was prepared from thermal oxidation of iron at 600 °C for 3 h in air atmosphere. This electrode with the structure of Fe₃O₄ and α-Fe₂O₃ showed the response of photoanodic current to the light with wavelength shorter than 600 nm. The band gap energy of this electrode was 1.99 eV. The onset potential of distinct steady photocurrent and also the flatband potential were 0.80 and 0.09 V vs. Ag/AgCl, respectively, in 0.1 M HNO₃ aqueous solution. The cell consisting of the iron oxide photoanode in HNO₃-Pb(NO₃)₂ and the graphite cathode in H₂SO₄-Ce(SO₄)₂ caused the PbO₂ deposit on the surface of the former electrode due to visible light irradiation without application of voltage. By holding the potential of this electrode at more positive value than 0.90 V, the photoanodic removal rate of Pb²⁺ in HNO₃-Pb(NO₃)₂ solution was higher than that observed when Ce⁴⁺ was used as electron acceptor.     

Novel Perovskite-Type Oxide Catalysts for Dehydrogenation of Ethylbenzene to Styrene

We investigated novel LaMnOx perovskite-oxide (ABO₃) catalysts for effective catalytic dehydrogenation of ethylbenzene to produce styrene monomer. Comparison with industrial Fe–K catalyst, our La_0.8Ba_0.2Mn_0.6Fe_0.4O_3-δ catalyst showed higher activity. Results show that the A-site in perovskite-type oxides affected catalytic dehydrogenation activities and that the B-site affected stability of the activities.     

Regulation of Neutrophil Functions by Hv1/VSOP Voltage-Gated Proton Channels

The voltage-gated proton channel, Hv1, also termed VSOP, was discovered in 2006. It has long been suggested that proton transport through voltage-gated proton channels regulate reactive oxygen species (ROS) production in phagocytes by counteracting the charge imbalance caused by the activation of NADPH oxidase. Discovery of Hv1/VSOP not only confirmed this process in phagocytes, but also led to the elucidation of novel functions in phagocytes. The compensation of charge by Hv1/VSOP sustains ROS production and is also crucial for promoting Ca²⁺ influx at the plasma membrane. In addition, proton extrusion into neutrophil phagosomes by Hv1/VSOP is necessary to maintain neutral phagosomal pH for the effective killing of bacteria. Contrary to the function of Hv1/VSOP as a positive regulator for ROS generation, it has been revealed that Hv1/VSOP also acts to inhibit ROS production in neutrophils. Hv1/VSOP inhibits hypochlorous acid production by regulating degranulation, leading to reduced inflammation upon fungal infection, and suppresses the activation of extracellular signal-regulated kinase (ERK) signaling by inhibiting ROS production. Thus, Hv1/VSOP is a two-way player regulating ROS production. Here, we review the functions of Hv1/VSOP in neutrophils and discuss future perspectives.     

Relation between crystal structure and lattice oxygen content of sintered reaction-bonded silicon nitride

When reaction-bonded silicon nitride containing MgO/Y₂O₃ additives is sintered at three different temperatures to form sintered reaction-bonded silicon nitride (SRBSN), the thermal conductivity increases with sintering temperature. The β-Si₃N₄ (silicon nitride) crystals of SRBSN ceramics were synthesized and characterized to investigate the relation between the crystal structure and the lattice oxygen content. The hot-gas extraction measurement result and the crystal structure obtained using Rietveld analysis suggested that the unit cell size of the β-Si₃N₄ crystal increases with the decrease in the lattice oxygen content. This result is reasonable considering that the lattice oxygen with the smaller covalent radius substitutes nitrogen with the larger one in the β-Si₃N₄ crystals. The lattice oxygen content decreased with increasing sintering temperature which also correlated with increase in thermal conductivity. Moreover, it is noteworthy from the viewpoint that it may be possible to apply the lattice constant analysis for the nondestructive and simple measurement of the lattice oxygen content that deteriorates the thermal conductivity of the β-Si₃N₄ ceramics.     

Heat transfer correlation of film boiling from a downward-facing horizontal circular plate

Correlation equations for saturated and subcooled film boiling heat transfer from a downward-facing horizontal circular plate are proposed based on a theoretical study using an integral method. For the case of subcooled liquids, a dimensionless heat transfer parameter is introduced to effectively correlate within ±15% the experimental data obtained under both quenching and steady-state conditions. © 1998 Scripta Technica, Heat Trans Jpn Res, 26(7): 459–468, 1997     

Purification and characterization of a novel glutamyl aminopeptidase from chicken meat

A novel glutamyl aminopeptidase (aminopeptidase A, EC 3.4.11.7) was purified from chicken meat by ammonium sulfate fractionation, ethanol fractionation, heat treatment, and successive column chromatographies of DEAE-Sepharose CL-6B and Sephadex G-200. The purified enzyme migrated as a single band on SDS-PAGE. The molecular weight of this enzyme was found to be 55,000 and 550,000 by SDS-PAGE and Sephadex G-200 column chromatographies, respectively. This enzyme hydrolyzed Glu- and Asp-, but not Leu-, Arg-, and Ala-2-naphthylamide (-2NA) at all. The optimum pH and temperature for hydrolysis of Glu-2NA was 7.5. and 70°C, respectively. Reducing agents such as cysteine and dithiothreitol inhibited the activity of this enzyme at concentrations of 1 mM. However, the activation by Ca(2+) and the inhibition by amastatin were not observed.