18 research outputs found

    Li1.4Al0.4Ge0.4Ti1.4(PO4)3 promising NASICON-structured glass-ceramic electrolyte for all-solid-state Li-based batteries: Unravelling the effect of diboron trioxide

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    Li-ion batteries (LIBs) are the ubiquitous technology to power portable electronics; however, for the next-generation of high-performing electrochemical energy storage systems for electric vehicles and smart grid facilities, breakthroughs are needed, particularly in the development of solid-state electrolytes, which may allow for enhanced energy density while enabling lithium metal anodes, combined with unrivalled safety and operative reliability. In this respect, here we present the successful synthesis of a glass-ceramic Li1.4Al0.4Ge0.4Ti1.4(PO4)3 NASICON-type solid-state electrolyte (SSE) through a melt-casting technique. Being grain boundaries crucial for the total ionic conductivity of SSEs, the effect of the addition of diboron trioxide (B2O3, 0.05 wt.%) to promote their liquefaction and restructuring is investigated, along with the effects on the resulting microstructures and ionic conductivities. By the thorough combination of structural-morphological and electrochemical techniques, we demonstrate that bulk materials show improved performance compared to their powder sintered counterpart, achieving remarkable ion mobility (> 0.1 mS cm–1 at –10 °C) and anodic oxidation stability (> 4.8 V vs Li+/Li). The addition of B2O3 positively affects the grain cohesion and growth, thus reducing the extension of the grain boundaries (and the related grain/grain interface resistance) and, therefore, increasing the overall ion mobility. In addition, B2O3 is seen to contrast the microcracks formation in the LAGTP system under study which, overall, shows very promising prospects as SSE for the next-generation of high-energy density, safe lithium-based batteries

    Hydrothermally-assisted recovery of Yttria- stabilized zirconia (YSZ) from end-of-life solid oxide cells

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    Effective and scalable recycling strategies for the recovery of critical raw materials are yet to be validated for solid oxide cells (SOCs) technologies. The current study aimed at filling this gap by developing optimized recycling processes for the recovery of Yttria-stabilized Zirconia (YSZ) from End-of-Life (EoL) SOC components, in view of using the recovered ceramic phase in cell re-manufacturing. A multi-step procedure, including milling, hydrothermal treatment (HT), and acidic-assisted leaching of nickel from composite Ni-YSZ materials, has been implemented to obtain recovered YSZ powders with defined specifications, in terms of particle size distribution, specific surface area, and chemical purity. The overall optimized procedure includes a pre-milling step (6 h) of the EoL composite materials, and a hydrothermal (HT) treatment at 200 °C for 4 h to further disaggregate the sintered composite, followed by selective oxidative leaching of Ni2+ by HNO3 solution at 80 °C for 2 h. In particular, the intermediate HT step was assessed to play an essential role in promoting the disaggregation of the sintered powders, with a related increase of specific surface area (up to 13 m2 g−1) and the overall reduction of the primary particle aggregates. The acid-assisted leaching allowed to fully extract Nickel from the composite Ni-YSZ powders, with retention of YSZ crystallinity and negligible loss of Zr and Y, as revealed by ICP analysis on the recovered supernatants. The developed multi-step pathway offers a promising strategy to recover valuable YSZ materials for the re-manufacturing of SOCs components, with the aim to boost a circular economy approach in the field of fuel-cell and hydrogen (FCH) technologies

    Fast-quenched Na<sub>2</sub>Si<sub>2</sub>O<sub>5</sub> stability and properties in crystalline composite

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    The sinter-crystallisation method of as-casted glass-based materials is effective for obtaining glass ceramics with different functional properties. We here report the microstructural, chemical composition, and ion dynamics of a fast Na-ion conductor Na2Si2O5 synthesised by the melt-quenching route. The parent glass is treated under different temperatures and crystallisation times. The analysis shows that the electrical properties strongly depend on the material's microstructural properties and thermal history. The fast-quenched materials achieve greater stability and electrical properties, outperforming the solid-state reaction methods and SrSiO3-Na2Si2O5 composites. We show that the crystalline regions in the sintered material act as nucleation centres for the recrystallised Na2Si2O5 phase, affecting the conductivity. The melt-quenched material shows a high conductivity of 10−1 S cm−1 at 750°C. Furthermore, the recrystallisation process of Na2Si2O5 is reversible, leading to a facile regeneration of the ionic properties

    Severe parainfluenza pneumonia in a case of transient hypogammalobulinemia of infancy

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    Human parainfluenza viruses (HPIVs) infection, largely known to cause self-limiting bronchiolitis and pneumonia in immune competent patients, can lead to severe to fatal pulmonary disease in immune disorders, such as primary or acquired-immune deficiencies. We report the case of a 1-year-old child who developed an acute respiratory distress syndrome. Because of a progressive respiratory failure unresponsive to conventional treatment extracorporeal membrane oxygenation (ECMO) was rapidly started. HPIV-3 infection was diagnosed on the rhinopharyngeal fluid and immunological examinations revealed a hypogammaglobulinemia. A combination therapy with ribavirin, intravenous immunoglobulin (IVIG) and steroid under ECMO support was started with considerable improvement. Subsequent analysis and more specific immunological assessment resulted normal confirming the diagnosis of transient hypogammaglobulinemia of infancy (THI). This case highlights the importance of prompt therapy with early ECMO support in combination with ribavirin, IVIG and steroids in patients affected by severe HPIV-3 pneumonia and THI

    New findings concerning cardiovascular manifestations emerging from long-term follow-up of 150 patients with the Williams-Beuren-Beuren syndrome.

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    AIMS: We investigated the prevalence, type, and course of congenital cardiac defects and systemic hypertension in our patients with Williams-Beuren-Beuren syndrome. METHODS AND RESULTS: We reviewed the clinical records of all patients with Williams-Beuren syndrome examined between 1981 and 2006. We identified 150 patients, aged from 7 months to 45 years, with a follow-up from 6 months to 25 years, the mean being 6.4 years. A cardiac anomaly was present in 113 of the 150 patients (75%). Defects were typical in over four-fifths of the group. We found supravalvar aortic stenosis in 73 of 113 patients (64.6%), isolated in 43. Pulmonary stenosis, isolated in 18 cases, was found in 51 of 113 (45.1%), while aortic coarctation and mitral valvar prolapse were each found in 7 (6.2%), 3 of the lesions is isolation. Atypical defects were found in 19 patients, tetralogy of Fallot in 2, atrial septal defects in 4, aortic and mitral valvar insufficiencies in 1 each, bicuspid aortic valves in 2, and ventricular septal defects in 9, 4 of the last being isolated. Systemic hypertension, observed in 33 patients (22%), was poorly controlled in 10. Diagnostic and/or interventional cardiac catheterization was undertaken in 24 patients, with 30 surgical procedures performed in 26 patients. Of the group, 3 patients died. CONCLUSION: Cardiac defects were present in three-quarters of our patients. Pulmonary arterial lesions generally improved, while supravalvar aortic stenosis often progressed. Atypical cardiac malformations, particularly ventricular septal defects, occurred frequently. Systemic hypertension was found in one-fifth, even in the absence of structural cardiac defects. The short-term mortality was low

    The development of a Consensus Conference on Pediatric Procedural Sedation in the Emergency Department in Italy: From here where to?

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    Background: In Italy, as in many European countries, Pediatric Emergency Medicine is not formally recognized as a pediatric subspecialty, hindering nation-wide adoption of standards of care, especially in the field of procedural sedation and analgesia (PSA) in the Emergency Department (ED). For this reason PSA in Italy is mostly neglected or performed very heterogeneously and by different providers, with no reference standard. We aimed to describe the procedures and results of the first multidisciplinary and multi-professional Consensus Conference in Italy on safe and effective pediatric PSA in Italian EDs. Methods: The preparation, organization and conduct of the Consensus Conference, held in Florence in 2017, followed the recommended National methodological standards. Professionals from different specialties across the country were invited to participate. Results: Overall 86 recommendations covering 8 themes (pre-sedation evaluation, pharmacologic agents, monitoring, equipment and discharge checklists, training, non-pharmacologic techniques, the adult ED setting, impact on hospitalizations) were developed, taking into account the Italian training system and healthcare organization characteristics. Conclusion: The results of the first multidisciplinary and multi-professional Consensus Conference in Italy are meant to provide up-to-date national guidance to improve the standard of care of children undergoing painful and stressful procedures in the ED. The recommendations will be periodically updated as new relevant evidence is published

    From the Hartree dynamics to the Vlasov equation

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    We consider the evolution of quasi-free states describing N fermions in the mean field limit, as governed by the nonlinear Hartree equation. In the limit of large N, we study the convergence towards the classical Vlasov equation. For a class of regular interaction potentials, we establish precise bounds on the 0rate of convergence

    Mean field evolution of fermions with Coulomb interaction

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    We study the many body Schr\uf6dinger evolution of weakly coupled fermions interacting through a Coulomb potential. We are interested in a joint mean field and semiclassical scaling, that emerges naturally for initially confined particles. For initial data describing approximate Slater determinants, we prove convergence of the many-body evolution towards Hartree\u2013Fock dynamics. Our result holds under a condition on the solution of the Hartree\u2013Fock equation, that we can only show in a very special situation (translation invariant data, whose Hartree\u2013Fock evolution is trivial), but that we expect to hold more generally. \ua9 2017, Springer Science+Business Media New York
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