He diffraction study of the OH(1×1)−Ag(110) phase

Summary The OH(1×1)−Ag(110) phase obtained after H₂O dissociation on the O(2×1)−Ag(110) surface is investigated. Structural and electronic properties are studied by He diffractive scattering and angularly resolved ultraviolet photoemission spectroscopy (ARUPS). Diffractive data are interpreted in terms of the hard corrugated wall (HCW) potential leading to the determination of the corrugation function ζ(R). The shape of ζ(R) indicates that the phase under study is formed of OH rows along where hydroxil groups interact strongly. The interaction between rows instead is weak and essentially republsive. In honour of Prof. Fausto Fumi on the occasion of his retirement from teaching.     

Design of dimerization inhibitors of HIV-1 aspartic proteinase: A computer-based combinatorial approach

Inhibition of dimerization to the active form of the HIV-1 aspartic proteinase (HIV-1 PR) may be a way to decrease the probability of escape mutations for this viral protein. The Multiple Copy Simultaneous Search (MCSS) methodology was used to generate functionality maps for the dimerization interface of HIV-1 PR. The positions of the MCSS minima of 19 organic fragments, once postprocessed to take into account solvation effects, are in good agreement with experimental data on peptides that bind to the interface. The MCSS minima combined with an approach for computational combinatorial ligand design yielded a set of modified HIV-1 PR C-terminal peptides that are similar to known nanomolar inhibitors of HIV-1 PR dimerization. A number of N-substituted 2,5-diketopiperazines are predicted to be potential dimerization inhibitors of HIV-1 PR.     

Potentiometric behaviour of the copper electrode in aqueous copper(II) perchlorate solutions containing sodium chloride

It is demonstrated that the copper metal electrode corrodes in the presence of copper(II) ions in solution. A model based on mass balance can properly describe the experimental results. In the presence of copper(II) ions the copper electrode responds to copper(I), indicating that the electrode potential corresponds to a mixed potential.     

The Time Scale of Electronic Resonance in Oxidized DNA as Modulated by Solvent Response: An MD/QM-MM Study

The time needed to establish electronic resonant conditions for charge transfer in oxidized DNA has been evaluated by molecular dynamics simulations followed by QM/MM computations which include counterions and a realistic solvation shell. The solvent response is predicted to take ca. 800–1000 ps to bring two guanine sites into resonance, a range of values in reasonable agreement with the estimate previously obtained by a kinetic model able to correctly reproduce the observed yield ratios of oxidative damage for several sequences of oxidized DNA.     

Compatibility of paroxetine hydrochloride and GW597599B

In this study, we present a full thermal characterization of antidepressant paroxetine and summarize the results for another drug which treats depression: GW597599B. The main aim is to analyze how the thermodynamic and structural properties of these compounds are modified when the two drugs are mixed in the solid state. We begin by putting into evidence how dehydration and melting concur in shaping the calorimetric curves of paroxetine under different experimental conditions. Equipped with this knowledge, we are able to interpret the thermal response of the physical mixtures paroxetine:GW597599B, in terms of partial eutectic formation and simple superposition of contribution from the two compounds.     

Mechanically assisted solid state synthesis of Mg2SnO4

Simultaneous TG?CDSC measurements have been used to study the solid state reaction in the system SnC₂O₄?C4MgCO₃·Mg(OH)₂·xH₂O (Sn:Mg?=?0.5). The results obtained with physically prepared mixture and with mixture mechanically activated by high-energy milling are compared. Synthesis of the compound Mg₂SnO₄ has been attempted starting from both type of mixture: Mg₂SnO₄ forms by annealing the activated mixture at temperatures between 850 and 1,000?°C while it can hardly be obtained from physical mixtures even by thermal treatment at temperature as high as 1,300?C1,350?°C. Mg₂SnO₄ prepared by annealing the activated mixture has been characterized by diffuse reflectance FT-IR spectroscopy, modulated temperature differential scanning calorimetry, scanning electron microscopy, and specific surface area measurements (B.E.T. method).     

News & views: New Scientific Opportunities at the European Synchrotron Radiation Facility

Approximately 400 participants learned about the latest scientific capabilities at the Stanford Synchrotron Radiation Lightsource (SSRL) and Linac Coherent Light Source (LCLS) during the 2013 Users' Meeting at the SLAC National Accelerator Laboratory, October 1–4, 2013. The Users' Meeting included more than a dozen workshops as well as scientific awards, poster presentations, and talks on the latest scientific trends, challenges, and opportunities.