Effect of salinity on nitrous oxide emission in the biological nitrogen removal process for industrial wastewater

The effects of wastewater salinity on both nitrogen removal efficiency and N2O emission rate were investigated in a single nitrification process, a single denitrification process and an anoxic-oxic activated sludge process. In the single nitrification process, by increasing the salt concentration from 1.0 to 2.0 wt%, the N2O conversion ratio in the steady state increased by 2.2 times, from 0.22 to 0.48%. In the single denitrification process, a minimal change in the N2O conversion ratio was observed in the steady state even when the salt concentration was increased from 3.0 to 5.0 wt%. From the results of the anoxic-oxic activated sludge process, it was found that a salt concentration increase from 1.6 to 3.0 wt% significantly increases the N2O conversion ratio from 0.7 to 13%. It is suggested that an increase in salt concentration markedly influences N2O emission both directly and indirectly via the inhibition of N2O reductase activity. The indirect inhibition is due to the high concentration of dissolved oxygen which is transported from the oxic tank to the anoxic tank through the circulated liquid. Thus, the salt concentration should be maintained below 3.0% to suppress N2O emission in an anoxic-oxic activated sludge process.     

Enantiomer-selective activation of racemic catalysts

Asymmetric catalysts can be evolved into highly activated catalysts by association with chiral activators. This asymmetric activation process is particularly useful in racemic catalysis through selective activation of one enantiomer of the racemic catalysts. Recently, a strategy whereby a racemic catalyst is selectively deactivated by a chiral additive has been reported to yield nonracemic products. However, we have reported a strategy that is an alternative to asymmetric catalysts but is conceptually opposite, in which a chiral activator selectively activates rather than deactivates one enantiomer of a racemic chiral catalyst. The advantage of this activation strategy over the deactivation counterpart is that the activated catalyst can produce a greater enantiomeric excess (x(act)% ee) in the products than the ee attained by the enantiomerically pure catalyst on its own. Therefore, 'asymmetric activation' could provide a general and powerful strategy for the use of not only atropisomeric and, hence, racemic ligands but also chirally flexible and 'pro-atropisomeric' ligands without enantiomeric resolution!     

GaInAsP/InP buried-heterostructure optical waveguides at a 1.5 μm wavelength

Buried-heterostructure GaInAsP/InP optical waveguides at a 1.5 ?m wavelength have been fabricated and a propagation loss of 2?2.5 cm?1 was obtained.     

Polarization insensitive traveling wave type amplifier usingstrained multiple quantum well structure

Signal gain agreement between TE and TM modes is realized under a specific operation condition in a traveling wave type amplifier using a strained multiple quantum well structure for the first time. The signal gain of the TM mode completely agrees with that of the TE mode at an amplifier driving current of 70 mA. The identical signal gain is 7.5 dB at present. However, the signal gain could be easily improved by using a device with a longer active region. In order to achieve polarization insensitive TWAs, the design parameter is the only confinement factor for the conventional bulk type     

Impact resistance of laterally confined fibre reinforced concrete plates

The effect of both biaxial and uniaxial lateral confinement on fibre reinforced concrete (FRC) plates under transverse impact loading was investigated. It was found that confinement had a major effect on the failure patterns as well as on the mechanical properties of both plain and fibre reinforced concretes. With different types and degrees of confinement, the failure changed from a flexural mode to a punching shear mode or a combined flexural-shear mode. With confinement, the apparent strength of concrete increased by up to two or three times and the inertial load decreased to a small enough fraction of the measured impact load that it could be ignored in the analysis. The ability of the FRC to absorb energy also increased with increasing confinement.

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Résumé Les effets du confinement bi-axial et uni-axial sur les propriétés de plaques de béton renforcé de fibres ont été examinés en conditions de choc. Il a été trouvé que le confinement a des effects majeurs sur le mode de rupture ainsi que sur les propriété mécaniques du béton normal et celles du béton de fibres. Avec un changement de confinement, le mode de rupture a également changé, passant de la flexion au cisaillement. En raison du confinement, la résistance du béton a doublé voire triplé, et le chargement inertiel a été réduit substantiellement. L'absorption d'énergie a aussi augmenté à cause du confinement.

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Editorial Note Prof. Sidney Mindess is a RILEM Senior Member and a Member of the Board of Editors of Material and Structures. Prof. N. Banthia is a Senior Member. He participates in the work of RILEM TCs 162-TDF (Test and design methods for steel fibre reinforced concrete) and 181-EAS (Early age shrinkage induced stresses and cracking in cementitious systems).     

Analysis of spinosad in animal and fishery products by LC-MS

We investigated the determination of spinosyn A and spinosyn D, the active ingredients of spinosad, in animal and fishery products by liquid chromatography with mass spectrometry (LC-MS). The sample was homogenized with 1 mol/L dipotassium hydrogenphosphate aqueous solution and extracted with acetone-n-hexane under mildly alkaline conditions. After n-hexane-acetonitrile partitioning using an EXtrelut(?) column, the extract was cleaned up on a tandem SAX/PSA mini-column, and examined by means of fragmenter-voltage-switching ESI-SIM mode LC-MS. Mean recoveries (n=5) of spinosyn A and spinosyn D from eleven kinds of fortified samples at the analyte concentration of 0.01 μg/g and 0.05 μg/g ranged from 76.1% to 93.8% (RSD≤8.7%) and from 75.1% to 104.1% (RSD≤8.6%), respectively.     

Degradation of myofibrils from rabbit, chicken and beef by cathepsin l and lysosomal lysates

The degradation of rabbit, chicken and beef myofibrils by cathepsin L or lysosomal lysates was studied by SDS-polyacrylamide-gel electrophoresis and electron microscopy (EM). Similar degradation patterns were observed for each myofibrillar preparation incubated with cathepsin L, except that myosin heavy chain and tropomyosin of beef were more susceptible than those of rabbit and chicken. Otherwise, troponin T, troponin in I and C-protein were rapidly degraded with slower degradation of titin, nebulin, myosin heavy chain, α-actinin, α-tropomyosin, actin and myosin light chains, LC1 and LC2. However, the component of 30 000 Mr was found to be further degraded to smaller peptides. Degradation at pH 5·5 (approximate post-mortem limit value) was faster than at pH 6·0 but slower than at pH 5·0. A number of new protein bands were identified (130 000, 120 000, 90 000, 85 000, 80 000, 31 000 and 30 000 Mr). The degradation patterns of rabbit myofibrils by rabbit muscle lysosomal lysates were similar to that of myofibrils incubated with purified cathepsin L except for the retention of the 30 000 Mr component and reduced degradation of actin, due presumably to the reduced amount or stability of cathepsin L in the crude enzyme preparations. Electron micrographs revealed that myofibrillar degradation by cathepsin L occurred preferentially at the Z-lines leading to removal of the Z-line proteins and fracturing of the myofibrils at these sites. Catheptic damage was seen to be most rapid in chicken myofibrils and least rapid in beef myofibrils consistent with the more rapid conditioning process in chicken.