Multi-component alloys containing 5 and 6 platinum group metals have been prepared by thermal decomposition of single-source precursors. It is the first successful example of high-entropy alloy preparation not requiring direct melting at high temperature or mechanical alloying, and can be further extended to other multicomponent metallic systems. Our single-source precursor strategy for the preparation of multicomponent alloys can be considered as a new approach in the design and optimization of refractory high-entropy alloys for a broad range of applications. Thermal decomposition occurs at low temperatures (below 800°C in H2 flow). The resulting hexagonal Ir0.19Os0.22Re0.21Rh0.20Ru0.19 alloy is the first example of a single-phase hexagonal high-entropy alloy. Heat treatment does not result in any phase changes up to 1500 K, which is a record temperature stability for a single-phase high-entropy alloy. Room temperature hydrostatic compression up to 45 GPa also highlights the system's stability as a single phase, with a bulk modulus smaller then individual platinum group metals (except Rh). The prepared alloys show pronounced electrocatalytic activity in methanol oxidation, which opens a route for the use of highentropy alloys as materials for sustainable energy conversion.

By means of empirical fits to the differential cross section data on pp andpp elastic scattering, above 10 GeV (center-of-mass energy), we determine the eikonal in the momentum -transfer space (q 2 -space). We make use of a numerical method and a novel semi-analytical method, through which the uncertainties from the fit parameters can be propagated up to the eikonal in the q 2 -space. A systematic study of the effect of the experimental information at large values of the momentum transfer is developed and discussed in detail. We present statistical evidence that the imaginary part of the eikonal changes sign in the q 2 -space and that the position of the zero decreases as the energy increases; after the position of the zero, the eikonal presents a minimum and then goes to zero through negative values. We discuss the applicability of our results in the phenomenological context, outlining some connections with nonperturbative QCD. A short review and a critical discussion on the main results concerning "model-independent" analyses are also presented.PACS. 13.85.Dz Elastic scattering -13.85.-t Hadron-induced high-energy interactions

Nontuberculous mycobacteria (NTM) are emergent pathogens whose importance in human health has been gaining relevance after being recognized as etiological agents of opportunist infections in HIV patients. Currently, NTM are recognized as etiological agents of several respiratory and extra-respiratory infections of immune-competent individuals. The environmental nature of NTM together with the ability to assemble biofilms on different surfaces plays a key role on their pathogenesis. In the present work the ability of three fast-growing NTM (Mycobacterium smegmatis, Mycobacterium fortuitum and Mycobacterium chelonae) to persist within a model of human alveolar macrophages was evaluated. Most often human infections with NTM occur by contact with the environment. Biofilms can work as environmental reservoirs. For this reason, it was decided to evaluate the ability of NTM to assemble biofilms on different surfaces. Scanning electron microscopy was used to elucidate the biofilm structure. The ability to assemble biofilms was connected with the ability to spread on solid media known as sliding. Biofilm assembly and intracellular persistence seems to be ruled by different mechanisms.

We present the results of fitting elastic $pp$ differential cross section data at 23.5 $\leq \sqrt{s} \leq$ 62.5 GeV with a novel analytic parametrization for the scattering amplitude. Making use of a fitting method, the errors from the free parameters are propagated to the imaginary part of the eikonal in the momentum transfer space. A novel systematic study of the effects coming from data at large momentum transfer is also performed. We find statistical evidence for the existence of eikonal zeros in the interval of momentum transfer 5-9 $GeV^{2}$.Comment: Text with 9 pages in Revtex (preprint form), 8 figures in PostScript. Replaced with small changes. Final version to be published in Physical Review

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