56 research outputs found

    Measurement of XUV-absorption spectra of ZnS radiatively heated foils

    Get PDF
    Time-resolved absorption of zinc sulfide (ZnS) and aluminum in the XUV-range has been measured. Thin foils in conditions close to local thermodynamic equilibrium were heated by radiation from laser-irradiated gold spherical cavities. Analysis of the aluminum foil radiative hydrodynamic expansion, based on the detailed atomic calculations of its absorption spectra, showed that the cavity emitted flux that heated the absorption foils corresponds to a radiation temperature in the range 55 60 eV. Comparison of the ZnS absorption spectra with calculations based on a superconfiguration approach identified the presence of species Zn6+ - Zn8+ and S5+ - S6+. Based on the validation of the radiative source simulations, experimental spectra were then compared to calculations performed by post-processing the radiative hydrodynamic simulations of ZnS. Satisfying agreement is found when temperature gradients are accounted for

    Radiative properties of stellar plasmas and open challenges

    Full text link
    The lifetime of solar-like stars, the envelope structure of more massive stars, and stellar acoustic frequencies largely depend on the radiative properties of the stellar plasma. Up to now, these complex quantities have been estimated only theoretically. The development of the powerful tools of helio- and astero- seismology has made it possible to gain insights on the interiors of stars. Consequently, increased emphasis is now placed on knowledge of the monochromatic opacity coefficients. Here we review how these radiative properties play a role, and where they are most important. We then concentrate specifically on the envelopes of β\beta Cephei variable stars. We discuss the dispersion of eight different theoretical estimates of the monochromatic opacity spectrum and the challenges we need to face to check these calculations experimentally.Comment: 6 pages, 5 figures, in press (conference HEDLA 2010

    Comparison with measuring method of internal story drift on shaking table test of 7 story x-lam building

    No full text
    Time-history response analysis could be obtained good information of seismic performance of timber structure building. Modelling that used of time history analysis usually based on the static test results of fasteners, walls and frames. Shaking table test is one of the effective methods to verify the reliability of model on dynamic behaviour. To verify the model’s reliability, shaking table test should be carried out in consideration of the weight of test building, acceleration of each layer and internal story drift of displacement. To measure internal story drift is rather difficult and important factor, because the rigid tower for measuring displacement within the table as ordinary static loading test. CNR-IVALSA have been established SOFIE project on sustainable buildings used cross-laminated panels(X-LAM) and shaking table test on 7 story X-LAM building was carried out E-Defense in MIKI city on cooperation research with NIED, Shizuoka University and BRI in Japan. In this tested we could try two methods for measuring the internal story drift. One is displacement transducer setting in the building for measuring relative displacement between floor and ceiling, the other is optical displacement measuring system that optical transmitter is attached to the building and optical receiver is placed out of the table. In this report, internal story drift was compared with accumulated displacement measuring transducer in the building and difference displacement of table and optical transmitter. Optical displacement system is necessary to compensate the angle of roll, pitch and yaw on the table. Comparison with test results, long direction of building that mainly shear deformation shows good agreement of two measuring results, but short direction of building that include bending deformation shows optical displacement is larger than the accumulated displacement in the building

    Effects of sodium butyrate treatment on histone modifications and the expression of genes related to epigenetic regulatory mechanisms and immune response in European sea bass (Dicentrarchus labrax) fed a plant-based diet.

    Get PDF
    Bacteria that inhabit the epithelium of the animals\u2019 digestive tract provide the essential biochemical pathways for fermenting otherwise indigestible dietary fibers, leading to the production of short-chain fatty acids (SCFAs). Of the major SCFAs, butyrate has received particular attention due to its numerous positive effects on the health of the intestinal tract and peripheral tissues. The mechanisms of action of this four-carbon chain organic acid are different; many of these are related to its potent regulatory effect on gene expression since butyrate is a histone deacetylase inhibitor that play a predominant role in the epigenetic regulation of gene expression and cell function. In the present work, we investigated in the European sea bass (Dicentrarchus labrax) the effects of butyrate used as a feed additive on fish epigenetics as well as its regulatory role in mucosal protection and immune homeostasis through impact on gene expression. Seven target genes related to inflammatory response and reinforcement of the epithelial defense barrier [tnf\u3b1 (tumor necrosis factor alpha) il1\u3b2, (interleukin 1beta), il-6, il-8, il-10, and muc2 (mucin 2)] and five target genes related to epigenetic modifications [dicer1(double-stranded RNA-specific endoribonuclease), ehmt2 (euchromatic histone-lysine-N-methyltransferase 2), pcgf2 (polycomb group ring finger 2), hdac11 (histone deacetylase-11), and jarid2a (jumonji)] were analysed in fish intestine and liver. We also investigated the effect of dietary butyrate supplementation on histone acetylation, by performing an immunoblotting analysis on liver core histone extracts. Results of the eight-week-long feeding trial showed no significant differences in weight gain or SGR (specific growth rate) of sea bass that received 0.2% sodium butyrate supplementation in the diet in comparison to control fish that received a diet without Nabutyrate. Dietary butyrate led to a twofold increase in the acetylation level of histone H4 at lysine 8, but showed no effect on the histone H3 at Lys9. Moreover, two different isoforms of histone H3 that might correspond to the H3.1 and H3.2 isoforms previously found in terrestrial animals were separated on the immunoblots. The expression of four (il1 \u3b2, il8, irf1, and tnf\u3b1) out of seven analyzed genes related to mucosal protection and inflammatory response was significantly different between the two analyzed tissues but only il10 showed differences in expression due to the interaction between tissue and butyrate treatment. In addition, butyrate caused significant changes in vivo in the expression of genes related to epigenetic regulatory mechanisms such as hdac11, ehmt2, and dicer1. Statistical analysis by two-way ANOVA for these genes showed not only significant differences due to the butyrate treatment, but also due to the interaction between tissue and treatment
    corecore