Etude de nouveaux pnictures ternaires de metaux de transition isostructuraux des phases G,Ni16Mn6P7, Ni16Mn6As7

The structural properties of the new ternary phosphide and arsenide of nickel and manganese Ni₁₆Mn₆P₇ and Ni₁₆Mn₆As₇ have been investigated. This crystal structure as determined by powder X-ray diffraction was found to be the well known structure of the G phases of germanides and silicides.     

Numerical simulation of non-perforating impacts on shielded gas-filled pressure vessels

In order to calibrate the output of hydrocode simulations of hypervelocity impacts on shielded gas-filled pressure vessels, Light Gas Gun impact experiments were performed. In a first step, tests were performed on so-called equivalent Whipple shield (EWS) configurations having basically the same set-up as the shielded pressure vessels (i.e. bumper thickness and - material, stand-off and backwall plate thickness and -material). Purpose was the determination of the impact conditions that lead to penetration into the backwall plate but not perforation of it or leakage through the impacted area. In a second step, impact tests on the corresponding shielded pressure vessels were performed with the same test conditions as the EWS. The purpose of the tests was the investigation whether leakage occurs when the vessel's front wall is not perforated, but just cratered. The test conditions lead to no leakage in all tests. The most important measured damage parameter was the crater depth of the deepest crater in the vessel's front wall/the backwall plate of the EWS, respectively. Hydrocode simulations were then performed to assess the capability of the numerical tool to correctly predict the damage on the impacted vessel surface. Normal impacts of aluminium spheres against shielded vessels were simulated using AUTODYN-2D, including and evaluating the effect of the static stress induced in the vessel walls by the inner pressure. Particular attention was focused on the exact determination of the maximum crater depth caused by the debris cloud impact on the vessel wall/the backwall plate of the EWS, respectively. Bumper and projectile were represented by SPH particles, the vessel shell was represented by a Lagrange grid. The results showed a very good agreement with the measured crater depths of the experiments.     

Solvent vapour monitoring in work space by solid phase micro extraction

Solid phase micro extraction (SPME) is a fast, solvent-less alternative to conventional charcoal tube sampling/carbon disulfide extraction for volatile organic compounds (VOC). In this work, SPME was compared to the active sampling technique in a typical lab atmosphere. Two different types of fibre coatings were evaluated for solvent vapour at ambient concentration. A general purpose 100 microm film polydimethylsiloxane (PDMS) fibre was found to be unsuitable for VOC work, despite the thick coating. The mixed-phase carboxen/PDMS fibre was found to be suitable. Sensitivity of the SPME was far greater than charcoal sorbent tube method. Calibration studies using typical solvent such as dichloromethane (DCM), benzene (B) and toluene (T) showed an optimal exposure time of 5 min, with a repeatability of less than 20% for a broad spectrum of organic vapour. Minimum detectable amount for DCM is in the range of 0.01 microg/l (0.003 ppmv). Variation among different fibres was generally within 30% at a vapour concentration of 1 microg DCM/l, which was more than adequate for field monitoring purpose. Adsorption characteristics and calibration procedures were studied. An actual application of SPME was carried out to measure background level of solvent vapour at a bench where DCM was used extensively. Agreement between the SPME and the charcoal sampling method was generally within a factor of two. No DCM concentration was found to be above the regulatory limit of 50 ppmv.     

Ozone Treatment of Sewage Works' Final Effluent

This paper describes a laboratory-based study which was designed to investigate (a) the changes in selected physico-chemical properties of a sewage-works' final effluent after ozonation, and (b) the effect of ozone on the concentration of organic halides and effluent toxicity and mutagenicity. Different conditions were studied involving the application of ozone concentrations up to 13.5% w/w and the ozonation of the effluent under both constant and variable ozonation rates.     

Ballistic limit equation for equipment placed behind satellite structure walls

A new ballistic limit equation has been developed for the case of a Whipple shield configuration or a sandwich panel with honeycomb core placed in front of a backwall. This “triple plate” ballistic limit equation considers explicitly the thicknesses, materials and spacings of each of the three plates. The third plate, i.e., the backwall, represents the cover plate or external wall of the equipment that is placed behind the satellite structure wall. The ballistic limit equation has been calibrated with experimental results obtained from hypervelocity impact tests on satellite equipment that was placed behind typical satellite structure walls. The equipment considered were fuel and heat pipes, pressure vessels, electronic boxes, harness, and batteries, all representative of real satellite equipment. The new equation was applied to prove that if the inherent protection capability of satellite equipment against hypervelocity impacts is explicitly considered in a ballistic limit equation, the critical projectile diameters for failure of such equipment are raised considerably compared to the case where equipment is assumed to fail as soon as the structure wall that protects it is perforated.     

Chorionic gonadotropin inhibits rat mammary carcinogenesis through activation of programmed cell death

Human chorionic gonadotropin (hCG) inhibits the progression of 7,12-dimethylbenz[a]anthracene (DMBA) induced mammary carcinomas. In order to determine whether this phenomenon was mediated by induction of programmed cell death or apoptosis, 45-day-old virgin Sprague-Dawley rats received 8 mg DMBA/100 g body weight; 20 days later they were injected daily with 100 IU hCG for 40 days (DMBA + hCG group). Age-matched untreated, hCG- and DMBA + saline treated rats were used as controls. Tissues were collected at the time of DMBA administration and at 5, 10, 20 and 40 days of hCG injection. RNA from mammary glands, adenocarcinomas and ovaries was probed for transforming growth factors (TGF) alpha and beta, and the apoptotic genes TRPM2, ICE, bcl2, bcl-XL, bcl-XS, p53 and c-myc. The mammary glands of hCG-treated animals with or without DMBA exhibited elevated expression of TRPM2, ICE, bcl-XS, c-myc and p53; and elevation in the apoptotic index. Mammary adenocarcinomas developed in those animals treated with hCG showed an elevation in the expression of p53, c-myc and ICE genes in comparison with the levels detected in the adenocarcinomas developed by the animals treated with DMBA alone. No significant alterations in the expression of any of the genes tested was observed in ovarian RNAs. These results led us to conclude that hCG induces programmed cell death in the mammary gland initiated in the carcinogenic process, that this process is p53 dependent, and is modulated by c-myc expression. Our data also indicate the possibility that a cell death program dependent on the bcl2 family exists, because of the potential involvement of p53, bcl-XS and Bax in apoptosis. This additional mechanism of tumor inhibition makes hCG treatment a useful approach for the prevention and therapy of breast cancer.     

Selective attention and performance with a multidimensional visual display.

Studied selective attention, using data from 63 adult Ss collected in 4 experiments in which stimuli varied in both spatial location and visual form. In Exp I, the likely location and likely form of targets were both precued. An advantage was found for cued over uncued forms at both cued and uncued locations. In Exps II, III, and IV, different forms tended to occur at different locations. Regardless of whether a location was cued or uncued, form selective effects were found in accordance with form probability for that location. It was not the case that selective attention simply favored certain locations or certain stimulus forms in preference to others. Rather, selective attention was sensitive to precise combinations of form and location. It is concluded that these results can not be reconciled with mental spotlight notions of spatial selectivity. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Two post thinning fertilizer trials inPinus radiata in New South Wales,Australia

Two trials inPinus radiata growing on different sites in N.S.W. allowed consideration of fertilizer applications after 2nd or 3rd thinning. The trials included factorial applications of N and P at a single thinning intensity plus a further treatment which allowed assessment of different thinning intensities. The most significant growth responses were obtained by application of N and P in combination. The largest response (additional productivity compared with the unfertilized control) occurred 4 years after application and after 7 years there was no additional absolute response for either of the two sites. The largest fertilizer response was 70 m³ ha^–1 over 7 years on one site and 36 m³ ha^–1 on the other, indicating differences in absolute responses between sites. It was concluded that in planning treatments the most responsive sites near the end of the rotation should be selected to maximise economic returns. Foliage analyses indicated differences between sites at the commencement of the study. It was concluded that either a single year of foliage analyses at study commencement is of value, or sampling every year of the study should be used to analyse responses, but a single year of analysis during or at the end of the study would not be of value.     

Probing the hydrophobic pocket of the active site of aromatase with 4-phenoxy-7 alpha-(phenylthio)-4-androstene-3,17-dione

In order to examine the nature of the hydrophobic pocket at the active site of aromatase, we carried out the synthesis, biochemical evaluation, and molecular modeling studies on 4-phenoxy-7 alpha-(phenylthio)-4-androstenedione 2. Aromatase inhibitory activity of 2 was found to be significantly weaker than that of the 4- and 7 alpha-mono(phenylthio)-substituted derivatives of androstenedione. These results along with those obtained from the modeling studies suggest the existence of a single hydrophobic pocket corresponding to the alpha-face in the C4, C6, C7 region of androstenedione.