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.     

Reaction of coal with quinoline during extraction

Yubari coal vitrite was extracted with quinoline at 420° C for 0–4 h and the products were separated into several fractions. Quinoline solubles (QS) and insolubles (QI) increased with time and the total recovered weight became nearly 200% of the original weight of the coal. A large part of this weight increase was due to the contribution of the formation of biquinoline and to quinoline addition to coal. Depolymerization to smaller molecules and polymerization to QI took place simultaneously via the addition of quinoline and the production of biquinoline.     

Hemostasis of gastric variceal hemorrhage by transileocoecal and transhepatic obliteration

On the basis of the latest achievements in anesthesia and reanimation, as well as the results of special military medical exercises and documents which depict the experience of local wars, the article shows the basic features of a conception about field anesthesia and reanimation. Taking into account the experience gained in Afghanistan the author determines the principles of its organization and approaches towards the solution of important tasks assigned to anesthesiological and reanimation service in combat conditions.     

Polarization-dependent refractive-index change induced bysuperlattice disordering

A model of the polarization-dependent refractive-index change that accompanies superlattice disordering is proposed for the first time. Calculated results agree well with experimental results in terms of the amount and direction of the refractive-index changes. In the GaAs-AlAs system, a simple diffusion model that considers the diffusion of group III atoms explains the experimental results. In a InGaAs-InP system, it is assumed that group V atoms mainly induce disordering, and the difference between the diffusion constant in wells and that in barriers is taken into account. The refractive-index changes induced by superlattice disordering are useful for fabricating polarization control devices and integrated optical circuits     

Substrate specificity and some other enzymatic properties of dihydroceramide desaturase (ceramide synthase) in fetal rat skin

Dihydroceramide desaturase, which catalyzes the introduction of a double bond at the 4,5-position of the sphingosine base in a dihydroceramide, was assayed in vitro using radiolabeled D-erythro-C18-dihydroceramide (N-stearoyl sphinganine) and homogenates of fetal rat skin, and some enzymatic properties, including substrate specificity, were determined. The ceramide structure, as the enzymatic product, was confirmed by (i) oxidation of the product with 2,3-dicyano-5,6-dichlorobenzoquinone, which revealed the conversion to 3-ketoceramide (3,3'-didehydroceramide), indicating that a double bond was introduced at the adjacent to the C-3 hydroxyl residue of sphinganine, and (ii) mass spectrometry of a long chain base released from the enzymatic product, which revealed a spectrum identical to that of authentic sphingenine. A short chain dihydroceramide, which was radiolabeled at sphinganine through a newly established method, having a C2- or C6-fatty acid was not desaturated by the skin enzyme, whereas that having a C10-, C14-, or C18-acid was desaturated, maximal reactivity being observed for the C14-dihydroceramide. Other enzymatic properties were confirmed: NAD(H) or NADP(H) and a detergent were required for elevation of the activity; the optimum pH was approximately 6.7; and metal cations were not essential, but Zn2+, Cu2+, and Fe2+ were rather inhibitory. These properties of rat skin desaturase were partly similar to those of rat liver microsomes, as reported recently, however, their substrate specificities were different.     

Syntheses and preventive effects of analogues related to 1alpha,25-dihydroxy-2beta-(3-hydroxypropoxy)vitamin D3 (ED-71) on bone mineral loss in ovariectomized rats

Analogues related to 1alpha,25-dihydroxy-2beta-(3-hydroxypropoxy)vitamin D3 (ED-71) (2), 26,27-dimethyl ED-71 (3) and 26,27-diethyl ED-71 (4), were synthesized from lithocholic acid (5). In the study of the preventive effects of these analogues and ED-71 (2) on bone mineral loss in ovariectomized rats, 26,27-dimethyl ED-71 (3) showed the most potent activity.