42 research outputs found

    Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC

    Get PDF

    Meristemas: fontes de juventude e plasticidade no desenvolvimento vegetal

    Full text link

    Phase Behavior of Aqueous Na-K-Mg-Ca-CI-NO3 Mixtures: Isopiestic Measurements and Thermodynamic Modeling

    Get PDF
    A comprehensive model has been established for calculating thermodynamic properties of multicomponent aqueous systems containing the Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cl{sup -}, and NO{sub 3}{sup -} ions. The thermodynamic framework is based on a previously developed model for mixed-solvent electrolyte solutions. The framework has been designed to reproduce the properties of salt solutions at temperatures ranging from the freezing point to 300 C and concentrations ranging from infinite dilution to the fused salt limit. The model has been parameterized using a combination of an extensive literature database and new isopiestic measurements for thirteen salt mixtures at 140 C. The measurements have been performed using Oak Ridge National Laboratory's (ORNL) previously designed gravimetric isopiestic apparatus, which makes it possible to detect solid phase precipitation. Water activities are reported for mixtures with a fixed ratio of salts as a function of the total apparent salt mole fraction. The isopiestic measurements reported here simultaneously reflect two fundamental properties of the system, i.e., the activity of water as a function of solution concentration and the occurrence of solid-liquid transitions. The thermodynamic model accurately reproduces the new isopiestic data as well as literature data for binary, ternary and higher-order subsystems. Because of its high accuracy in calculating vapor-liquid and solid-liquid equilibria, the model is suitable for studying deliquescence behavior of multicomponent salt systems

    Recognition and characterization of binding modes of Δ- and Λ-[Ru(phen)3]2+ and Δ- and Λ-[Ru(phen)2DPPZ]2+ by the 23Na NMR Relaxation and Binding Free Energy Parameters

    No full text
    Na-23 NMR relaxation rates were measured in Na-DNA aqueous solutions in the presence of Delta- or Lambda-enantiomer of [Ru(phen)(3)](2+) and [Ru(phen)(2)DPPZ](2+). From the analysis of the spin-lattice and spin-spin relaxation rates evidence is given that a decrease of the quadrupolar coupling constant for the slow motions occurs, due to the structural and dynamical modifications of DNA induced by the binding of the ruthenium complexes. Furthermore a linear dependence between the changes of the broad component, R-2bB, and the relative polyelectrolyte contributions to the binding free energy, Delta G(pe)/Delta G, was found. In particular for the intercalators Delta- and Lambda-[Ru(phen)(2)DPPZ](2+), a direct dependence on Delta G(pe)/Delta G was observed, as already found for ethidium, propidium and dq2pyp; while [Ru(phen)(3)](2+) complexes and the pure electrostatic Mg2+ showed an inverse dependence. These results have been discussed in terms of the polyelectrolyte interactions responsible for the R-2bB changes

    Recognition and characterization of binding modes of Δ- and Λ-[Ru(phen)3]2+ and Δ- and Λ-[Ru(phen)2DPPZ]2+ by the 23Na NMR Relaxation and Binding Free Energy Parameters

    No full text
    Na-23 NMR relaxation rates were measured in Na-DNA aqueous solutions in the presence of Delta- or Lambda-enantiomer of [Ru(phen)(3)](2+) and [Ru(phen)(2)DPPZ](2+). From the analysis of the spin-lattice and spin-spin relaxation rates evidence is given that a decrease of the quadrupolar coupling constant for the slow motions occurs, due to the structural and dynamical modifications of DNA induced by the binding of the ruthenium complexes. Furthermore a linear dependence between the changes of the broad component, R-2bB, and the relative polyelectrolyte contributions to the binding free energy, Delta G(pe)/Delta G, was found. In particular for the intercalators Delta- and Lambda-[Ru(phen)(2)DPPZ](2+), a direct dependence on Delta G(pe)/Delta G was observed, as already found for ethidium, propidium and dq2pyp; while [Ru(phen)(3)](2+) complexes and the pure electrostatic Mg2+ showed an inverse dependence. These results have been discussed in terms of the polyelectrolyte interactions responsible for the R-2bB changes
    corecore