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Now showing items 65 - 70 of 70

  • QRS pattern and improvement in right and left ventricular function after cardiac resynchronization therapy:a radionuclide study

    Domenichini, Giulia   Burri, Haran   Valzania, Cinzia   Gavaruzzi, Gilberto   Fallani, Francesco   Biffi, Mauro   Sunthorn, Henri   Diemberger, Igor   Martignani, Cristian   Foulkes, Huberdine   Fleury, Eric   Boriani, Giuseppe  

    Background: Predicting response to cardiac resynchronization therapy (CRT) remains a challenge. We evaluated the role of baseline QRS pattern to predict response in terms of improvement in biventricular ejection fraction (EF). Methods: Consecutive patients (pts) undergoing CRT implantation underwent radionuclide angiography at baseline and at mid-term follow-up. The relationship between baseline QRS pattern and mechanical dyssynchrony using phase analysis was evaluated. Changes in left and right ventricular EF (LVEF and RVEF) were analyzed with regard to baseline QRS pattern. Results: We enrolled 56 pts, 32 with left bundle branch block (LBBB), 4 with right bundle branch block (RBBB) and 20 with non-specific intraventricular conduction disturbance (IVCD). A total of 48 pts completed follow-up. LBBB pts had significantly greater improvement in LVEF compared to RBBB or non-specific IVCD pts (+ 9.6 +/- 10.9% vs. + 2.6 +/- 7.6%, p =3D 0.003). Response (defined as >=3D 5% increase in LVEF) was observed in 68% of LBBB vs. 24% of non-specific IVCD pts (p =3D 0.006). None of the RBBB pts were responders. RVEF was significantly improved in LBBB (+5.0 +/- 9.0%, p =3D 0.007), but not in non-specific IVCD and RBBB pts (+0.4 +/- 5.8%, p =3D 0.76). At multivariate analysis, LBBB was the only predictor of LVEF response (OR, 7.45; 95% CI 1.80-30.94; p =3D 0.006), but not QRS duration or extent of mechanical dyssynchrony. Conclusions: Presence of a LBBB is a marker of a positive response to CRT in terms of biventricular improvement. Pts with non-LBBB pattern show significantly less benefit from CRT than those with LBBB.
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  • Hydrogen Permeation Properties and Chemical Stability of Novel Pd-Free Alloy Membranes Based on the V-Y System

    Magnone, Edoardo   Jeon, Sung I.   Park, Jung H.   Fleury, Eric  

    No investigation has yet been accomplished to screen the yttrium-doped effects on vanadium-based metal membranes. Synthesis, hydrogen permeation properties, and chemical stability of a novel palladium (Pd)-coated V99Y1 alloy membrane are presented. Hydrogen permeation experiments have been performed to investigate the hydrogen transport properties through the Pd-coated V99Y1 alloy membrane in the pressure range of 1.53.0 bar under pure hydrogen as well as H2-CO2 and H2-CO gas mixtures at 400 degrees C. The maximum hydrogen permeation rate was similar to 32mLmin1cm2 for a 0.5mm thick membrane under pure hydrogen. The results offer new directions in the synthesis of novel non-Pd-based metal membranes for hydrogen separation in precombustion capture applications.
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  • Detailed contact data and the dissemination of Staphylococcus aureus in hospitals.

    Obadia, Thomas   Silhol, Romain   Opatowski, Lulla   Temime, Laura   Legrand, Judith   Thiebaut, Anne C M   Herrmann, Jean-Louis   Fleury, Eric   Guillemot, Didier   Boelle, Pierre-Yves  

    Close proximity interactions (CPIs) measured by wireless electronic devices are increasingly used in epidemiological models. However, no evidence supports that electronically collected CPIs inform on the contacts leading to transmission. Here, we analyzed Staphylococcus aureus carriage and CPIs recorded simultaneously in a long-term care facility for 4 months in 329 patients and 261 healthcare workers to test this hypothesis. In the broad diversity of isolated S. aureus strains, 173 transmission events were observed between participants. The joint analysis of carriage and CPIs showed that CPI paths linking incident cases to other individuals carrying the same strain (i.e. possible infectors) had fewer intermediaries than predicted by chance (P < 0.001), a feature that simulations showed to be the signature of transmission along CPIs. Additional analyses revealed a higher dissemination risk between patients via healthcare workers than via other patients. In conclusion, S. aureus transmission was consistent with contacts defined by electronically collected CPIs, illustrating their potential as a tool to control hospital-acquired infections and help direct surveillance. =20
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  • Nanometer-scale phase separation and formation of delta ZrH2 in Cu-Zr binary amorphous alloys

    Fadonougbo, Julien O.   Suh, Jin-Yoo   Shim, Cheol-Hwee   Kim, Gyeung-Ho   Fleury, Eric   Cho, Young Whan  

    Different Cu-Zr alloys were hydrogenated under 100 bars of hydrogen pressure at different temperatures. The hydrogenation induced transformation of the initially amorphous phase into a polycrystalline structure characterized by its nanoscale (<5 nm), mostly composed of metallic Cu and ZrH2. Calorimetry measurements after hydrogenation showed a low temperature exothermic transformation occurring in the alloys hydrogenated at temperatures below 473 K, followed by multiple endothermic peaks at higher temperature attributed to dehydrogenation of different hydride phases. Activation barrier energies of the phase transformation were derived from Kissinger's method, and further characterization involving transmission electron microscopy revealed the existence of delta ZrH2 with cubic structure contrasting with the typical epsilon ZrH2 with tetragonal structure. This study evidences the effect of hydrogen pressure, temperature, and the alloy chemistry on the nature of the hydride formation in Cu-Zr binary amorphous alloys during the hydrogenation procedure. (C) 2017 Elsevier B.V. All rights reserved.
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  • Non-altering time scales for aggregation of dynamic networks into series of graphs

    Leo, Yannick   Crespelle, Christophe   Fleury, Eric  

    Many dynamic networks coming from real-world contexts are link streams, i.e. a finite collection of triplets (u, v, t) where u and v are two nodes having a link between them at time t. A very large number of studies on these objects start by aggregating the data in disjoint time windows of length Delta in order to obtain a series of graphs on which are made all subsequent analyses. Here we are concerned with the impact of the chosen Delta on the obtained graph series. We address the fundamental question of knowing whether a series of graphs formed using a given Delta faithfully describes the original link stream. We answer the question by showing that such dynamic networks exhibit a threshold for Delta, which we call the saturation scale, beyond which the properties of propagation of the link stream are altered, while they are mostly preserved before. We design an automatic method to determine the saturation scale of any link stream, which we apply and validate on several real-world datasets. (C) 2018 Elsevier B.V. All rights reserved.
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  • Socioeconomic correlations and stratification in social-communication networks

    Leo, Yannick   Fleury, Eric   Ignacio Alvarez-Hamelin, J.   Sarraute, Carlos   Karsai, Marton  

    The uneven distribution of wealth and individual economic capacities are among the main forces, which shape modern societies and arguably bias the emerging social structures. However, the study of correlations between the social network and economic status of individuals is difficult due to the lack of large-scale multimodal data disclosing both the social ties and economic indicators of the same population. Here, we close this gap through the analysis of coupled datasets recording the mobile phone communications and bank transaction history of one million anonymized individuals living in a Latin American country. We show that wealth and debt are unevenly distributed among people in agreement with the Pareto principle; the observed social structure is strongly stratified, with people being better connected to others of their own socioeconomic class rather than to others of different classes; the social network appears to have assortative socioeconomic correlations and tightly connected 'rich clubs'; and that individuals from the same class live closer to each other but commute further if they are wealthier. These results are based on a representative, society-large population, and empirically demonstrate some long-lasting hypotheses on socioeconomic correlations, which potentially lay behind social segregation, and induce differences in human mobility.
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