Thermomechanical properties of amorphous metallic tungsten-oxygen and tungsten-oxide coatings

In this work, we investigate the correlation between morphology, composition, and the mechanical properties of metallic amorphous tungsten-oxygen and amorphous tungsten-oxide films deposited by Pulsed Laser Deposition. This correlation is investigated by the combined use of Brillouin Spectroscopy and the substrate curvature method. The stiffness of the films is strongly affected by both the oxygen content and the mass density. The elastic moduli show a decreasing trend as the mass density decreases and the oxygen-tungsten ratio increases. A plateaux region is detected in correspondence of the transition between metallic and oxide films. The compressive residual stresses, moderate stiffness and high local ductility that characterize compact amorphous tungsten-oxide films make them promising for applications involving thermal or mechanical loads. The coefficient of thermal expansion is quite high (i.e. 8.9 $\cdot$ 10$^{-6}$ K$^{-1}$), being strictly correlated to the amorphous structure and stoichiometry of the films. Under thermal treatments they show a quite low relaxation temperature (i.e. 450 K). They crystallize into the $\gamma$ monoclinic phase of WO$_3$ starting from 670 K, inducing an increase by about 70\% of material stiffness.Comment: The research leading to these results has also received funding from the European Research Council Consolidator Grant ENSURE (ERC-2014-CoG No. 647554). The views and opinions expressed herein do not necessarily reflect those of the European Commissio

Coefficient of thermal expansion of nanostructured tungsten based coatings assessed by thermally induced substrate curvature method

The in plane coefficient of thermal expansion (CTE) and the residual stress of nanostructured W based coatings are extensively investigated. The CTE and the residual stresses are derived by means of an optimized ad-hoc developed experimental setup based on the detection of the substrate curvature by a laser system. The nanostructured coatings are deposited by Pulsed Laser Deposition. Thanks to its versatility, nanocrystalline W metallic coatings, ultra-nano-crystalline pure W and W-Tantalum coatings and amorphous-like W coatings are obtained. The correlation between the nanostructure, the residual stress and the CTE of the coatings are thus elucidated. We find that all the samples show a compressive state of stress that decreases as the structure goes from columnar nanocrystalline to amorphous-like. The CTE of all the coatings is higher than the one of the corresponding bulk W form. In particular, as the grain size shrinks, the CTE increases from 5.1 10$^{-6}$ K$^{-1}$ for nanocrystalline W to 6.6 10$^{-6}$ K$^{-1}$ in the ultra-nano-crystalline region. When dealing with amorphous W, the further increase of the CTE is attributed to a higher porosity degree of the samples. The CTE trend is also investigated as function of materials stiffness. In this case, as W coatings become softer, the easier they thermally expand.Comment: The research leading to these results has also received funding from the European Research Council Consolidator Grant ENSURE (ERC-2014-CoG No. 647554

The never-ending story of the fight against tuberculosis: From Koch's bacillus to global control programs

Tuberculosis (TB) is one of the oldest diseases known to affect humanity, and is still a major public health problem. It is caused by the bacillus Mycobacterium tuberculosis (MT), isolated in 1882 by Robert Koch. Until the 1950s, X rays were used as a cheap method of diagnostic screening together with the tuberculin skin sensitivity test. In the diagnosis and treatment of TB, an important role was also played by surgery. The late Nineteenth century saw the introduction of the tuberculosis sanatorium, which proved to be one of the first useful measures against TB. Subsequently, Albert Calmette and Camille Gu\ue9rin used a non-virulent MT strain to produce a live attenuated vaccine. In the 1980s and 1990s, the incidence of tuberculosis surged as a major opportunistic infection in people with HIV infection and AIDS; for this reason, a combined strategy based on improving drug treatment, diagnostic instruments and prevention was needed

Experimental Study of a Parallel Iterative Solver for Markov Chain Modeling

This paper presents the results of a preliminary experimental investigation of the performance of a stationary iterative method based on a block staircase splitting for solving singular systems of linear equations arising in Markov chain modelling. From the experiments presented, we can deduce that the method is well suited for solving block banded or more generally localized systems in a parallel computing environment. The parallel implementation has been benchmarked using several Markovian models

RESPIRATORY VIRUSES IN ALPINE CHAMOIS

In the heterogeneous ecosystem of the Alps an interdisciplinary approach is necessary to prevent, survey and control wildlife diseases in order to ensure the biological integrity, the environmental conservation and so the biodiversity. In this contest the matter of livestock-wildlife interface is of particular importance for the presence of grazing domestic herds and the increase of wild ruminants populations, that lead to novel cohabitation situations with a possible \u201cspill-over\u201d of diseases from livestock or vice versa. Livestock-wildlife interfaces are dynamic and bidirectional and pathogens could be transmitted freely within and between the species. Mountain ungulates appear as a good biological model to study inter-species transmission and in particular, respiratory infections of wild ruminants. Chamois has already been subjected in the past to demographic decreases due to respiratory viruses\u2019 circulation. In this study a total of 394 chamois sera hunted in two different areas of North Western Italian Alps were analysed by virus-neutralization test to detect antibody against Bovine Respiratory Syncytial virus (BRSV), Bovine Viral Diarrhea virus (BVDV) and Mammalian Orthoreovirus (MRV). Seroprevalence of viruses and statistical analysis of antibody titres suggest that infection of pestivirus in chamois populations is sporadic as a spill-over from livestock; BRSV has a high adaptation level in wildlife and can be considered endemic in this two areas; high MRV seroprevalence has been observed and confirms the spread of MRV, that has been identified in a previous study in three chamois lungs. Furthermore, in this study PCR and phylogenetic analysis showed that chamois MRV strains belong to serotype 3 and are closely related to Italian dog and Italian bats strains

A case for associational resistance : Apparent support for the stress gradient hypothesis varies with study system

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Advantages of GPU-accelerated approach for solving the Parker equation in the heliosphere

The increasing of experimental observations' accuracy and model complexity requires the development of a new class of numerical solvers. In this work, we present a GPU-accelerated approach for solving the Parker equation in the heliosphere using a stochastic differential equation (SDE) approach. The presented method was applied to a generic system of SDE using the CUDA programming language. Our approach achieves significant speedup compared to a CPU implementation, allowing us to efficiently solve for the modulated spectra of charged particles in the heliosphere. We demonstrate the accuracy and efficiency of our method through numerical experiments on a realistic model of the heliosphere

Use of artificial intelligence to automatically predict the optimal patient-specific inversion time for late gadolinium enhancement imaging. Tool development and clinical validation

Introduction With the worldwide diffusion of cardiac magnetic resonance (CMR), demand on image quality has grown. CMR late gadolinium enhancement (LGE) imaging provides critical diagnostic and prognostic information, and guides management. The identification of optimal Inversion Time (TI), a time-sensitive parameter closely linked to contrast kinetics, is pivotal for correct myocardium nulling. However, determining the optimal TI can be challenging in some diseases and for less experienced operators. Purpose To develop and test an artificial intelligence tool to automatically predict the personalised optimal TI in LGE imaging. Methods The tool, named THAITI, consists of a Random Forest regression model. It considers, as input parameters, patient-specific TI determinants (age, gender, weight, height, kidney function, heart rate) and CMR scan-specific TI determinants (B0, contrast type and dose, time elapsed from contrast injection). THAITI was trained on 219 patients (3585 images) with mixed conditions who underwent CMR (1.5T; Gadobutrol; averaged, MOCO, free-breathing true-FISP IR [1]) for clinical reasons. The dataset was split with a 90–10 policy: 90% of data for training, and 10% for testing. THAITI’s hyperparameters were optimised by embedding k-fold cross validation into an evolutionary computation algorithm, and the best performing model was finally evaluated on the test set. A graphical user interface was also developed. Clinical validation was performed on 55 consecutive patients, randomised to experimental (THAITI-set TI) vs control (operator-set TI) group. Image quality was assessed blindly by 2 independent experienced operators by a 4-points Likert scale, and by means of the contrast/enhancement ratio (CER) (i.e., signal intensity of enhanced/remote myocardium ratio). Results In the testing set, the TI predicted by THAITI differed from the ground truth by ≥ 5ms in 16% of cases. At clinical validation, myocardial nulling quality did not differ between the experimental vs the control group either by CER or visual assessment, with an overall "optimal" or "good" nulling in 96% vs 93%, respectively. Conclusions Using main determinants of contrast kinetics, THAITI efficiently predicted the optimal TI for CMR-LGE imaging. The tool works as a stand-alone on laptops/mobile devices, not requiring adjunctive scanner technology and thus has great potential for diffusion, including in small or recently opened CMR services, and in low-resource settings. Additional development is ongoing to increase generalisability (multi-vendor, multi-sequence, multi-contrast) and to test its potential to further improve CMR-LGE image quality and reduce the need for repeated imaging for inexperienced operators. Figure 1. Top: THAITI interface. Bottom: examples of experimental group CMR-LGE imaging. Table 1. Control vs experimental group. Data expressed as absolute number (%), mean ± SD, median [IQR]. ⧧ T-test; * Chi-square

Host range of mammalian orthoreovirus type 3 widening to alpine chamois

Mammalian orthoreoviruses (MRV) type 3 have been recently identified in human and several animal hosts, highlighting the apparent lack of species barriers. Here we report the identification and genetic characterization of MRVs strains in alpine chamois, one of the most abundant wild ungulate in the Alps. Serological survey was also performed by MRV neutralization test in chamois population during five consecutive years (2008-2012). Three novel MRVs were isolated on cell culture from chamois lung tissues. No respiratory or other clinical symptoms neither lung macroscopic lesions were observed in the chamois population. MRV strains were classified as MRV-3 within the lineage III, based on S1 phylogeny, and were closely related to Italian strains identified in dog, bat and diarrheic pig. The full genome sequence was obtained by next-generation sequencing and phylogenetic analyses showed that other segments were more similar to MRVs of different geographic locations, serotypes and hosts, including human, highlighting genome reassortment and lack of host specific barriers. By using serum neutralization test, a high prevalence of MRV-3 antibodies was observed in chamois population throughout the monitored period, showing an endemic level of infection and suggesting a self-maintenance of MRV and/or a continuous spill-over of infection from other animal species