Ca(BH4)2–Mg2NiH4: on the pathway to a Ca(BH4)2 system with a reversible hydrogen cycle

The hydride composite Ca(BH4)2–Mg2NiH4 transfers all boron to MgNi2.5B2 upon dehydrogenation, avoiding boron sinks. The rehydrogenation to Ca(BH4)2 was confirmed

Dynamics of porous and amorphous magnesium borohydride to understand solid state Mg-ion-conductors

Rechargeable solid-state magnesium batteries are considered for high energy density storage and usage in mobile applications as well as to store energy from intermittent energy sources, triggering intense research for suitable electrode and electrolyte materials. Recently, magnesium borohydride, Mg(BH$_{4}$)$_{2}$, was found to be an effective precursor for solid-state Mg-ion conductors. During the mechanochemical synthesis of these Mg-ion conductors, amorphous Mg(BH$_{4}$)$_{2}$ is typically formed and it was postulated that this amorphous phase promotes the conductivity. Here, electrochemical impedance spectroscopy of as-received γ-Mg(BH$_{4}$)$_{2}$ and ball milled, amorphous Mg(BH$_{4}$)$_{2}$ confirmed that the conductivity of the latter is ~2 orders of magnitude higher than in as-received γ-Mg(BH$_{4}$)$_{2}$ at 353 K. Pair distribution function (PDF) analysis of the local structure shows striking similarities up to a length scale of 5.1 Å, suggesting similar conduction pathways in both the crystalline and amorphous sample. Up to 12.27 Å the PDF indicates that a 3D net of interpenetrating channels might still be present in the amorphous phase although less ordered compared to the as-received γ-phase. However, quasi elastic neutron scattering experiments (QENS) were used to study the rotational mobility of the [BH$_{4}$] units, revealing a much larger fraction of activated [BH$_{4}$] rotations in amorphous Mg(BH$_{4}$)$_{2}$. These findings suggest that the conduction process in amorphous Mg(BH$_{4}$)$_{2}$ is supported by stronger rotational mobility, which is proposed to be the so-called “paddle-wheel” mechanism

Hydrogen sorption in the LiH-LiF-MgB2 system

A composite material in the LiH-LiF-MgB2 system has been synthesized by high-energy ball milling. Some peaks in addition to that of the binary 2LiH-MgB2 and 2LiF-MgB2 systems are observed for the composite material by high-pressure differential scanning calorimetry (HP-DSC), indicating the formation of intermediate phases. In situ synchrotron radiation powder X-ray diffraction (SR-PXD) performed at 60 bar of H-2 and 390 degrees C shows a superposition of both reaction pathways that are typical for 2LiH-MgB2 and 2LiF-MgB2. After hydrogen absorption of the LiH-LiF-MgB2 composite the vibrational modes of LiBH4 were observed by attenuated total reflection infrared (ATR-IR) spectroscopy. The F-19 MAS NMR spectrum of the LiF-LiBH4 sample after heat treatment in hydrogen is strongly dominated by the centerband and spinning sidebands from LiF; in addition, a low-intensity resonance, very similar to that of [BF4](-) ion, is identified

Extracorporeal CO 2 Removal During Renal Replacement Therapy to Allow Lung-Protective Ventilation in Patients With COVID-19-Associated Acute Respiratory Distress Syndrome

The aim of this retrospective multicenter observational study is to test the feasibility and safety of a combined extracorporeal CO 2 removal (ECCO 2 R) plus renal replacement therapy (RRT) system to use an ultraprotective ventilator setting while maintaining (1) an effective support of renal function and (2) values of pH within the physiologic limits in a cohort of coronavirus infectious disease 2019 (COVID-19) patients. Among COVID-19 patients admitted to the intensive care unit of 9 participating hospitals, 27 patients with acute respiratory distress syndrome (ARDS) and acute kidney injury (AKI) requiring invasive mechanical ventilation undergoing ECCO 2 R-plus-RRT treatment were included in the analysis. The treatment allowed to reduce V T from 6.0 ± 0.6 mL/kg at baseline to 4.8 ± 0.8, 4.6 ± 1.0, and 4.3 ± 0.3 mL/kg, driving pressure (ΔP) from 19.8 ± 2.5 cm H 2 O to 14.8 ± 3.6, 14.38 ± 4.1 and 10.2 ± 1.6 cm H 2 O after 24 hours, 48 hours, and at discontinuation of ECCO 2 R-plus-RRT (T3), respectively ( p < 0.001). PaCO 2 and pH remained stable. Plasma creatinine decreased over the study period from 3.30 ± 1.27 to 1.90 ± 1.30 and 1.27 ± 0.90 mg/dL after 24 and 48 hours of treatment, respectively ( p < 0.01). No patient-related events associated with the extracorporeal system were reported. These data show that in patients with COVID-19-induced ARDS and AKI, ECCO 2 R-plus-RRT is effective in allowing ultraprotective ventilator settings while maintaining an effective support of renal function and values of pH within physiologic limits

Complex hydrides for energy storage

In the past decades, complex hydrides and complex hydrides-based materials have been thoroughly investigated as materials for energy storage, owing to their very high gravimetric and volumetric hydrogen capacities and interesting cation and hydrogen diffusion properties. Concerning hydrogen storage, the main limitations of this class of materials are the high working temperatures and pressures, the low hydrogen absorption and desorption rates and the poor cyclability. In the past years, research in this field has been focused on understanding the hydrogen release and uptake mechanism of the pristine and catalyzed materials and on the characterization of the thermodynamic aspects, in order to rationally choose the composition and the stoichiometry of the systems in terms of hydrogen active phases and catalysts/destabilizing agents. Moreover, new materials have been discovered and characterized in an attempt to find systems with properties suitable for practical on-board and stationary applications. A significant part of this rich and productive activity has been performed by the research groups led by the Experts of the International Energy Agreement Task 32, often in collaborative research projects. The most recent findings of these joint activities and other noteworthy recent results in the field are reported in this paper

Effect of the partial replacement of CaH2 with CaF2 in the Mixed System CaH2 + MgB2

In this work the effect of a partial replacement of CaH2 with CaF2 on the sorption properties of the system CaH2 + MgB2 has been studied. The first five hydrogen absorption and four desorption reactions of the CaH2 + MgB2 and 3CaH2 + CaF2 + 4MgB2 systems were investigated by means of volumetric measurements, high-pressure differential scanning calorimetric technique (HP-DSC), 11B and 19F MAS NMR spectroscopy, and in situ synchrotron radiation powder X-ray diffraction (SR-PXD). It was observed that already during the mixing of the reactants formation of a nonstoichiometric CaF2-xHx solid solution takes place. Formation of the CaF2-xHx solid solution sensibly affects the overall hydrogen sorption reactions of the system CaH2 + MgB2

Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications

BACKGROUND Limited information exists about the epidemiology and outcome of surgical patients at increased risk of postoperative pulmonary complications (PPCs), and how intraoperative ventilation was managed in these patients. OBJECTIVES To determine the incidence of surgical patients at increased risk of PPCs, and to compare the intraoperative ventilation management and postoperative outcomes with patients at low risk of PPCs. DESIGN This was a prospective international 1-week observational study using the ‘Assess Respiratory Risk in Surgical Patients in Catalonia risk score’ (ARISCAT score) for PPC for risk stratification. PATIENTS AND SETTING Adult patients requiring intraoperative ventilation during general anaesthesia for surgery in 146 hospitals across 29 countries. MAIN OUTCOME MEASURES The primary outcome was the incidence of patients at increased risk of PPCs based on the ARISCAT score. Secondary outcomes included intraoperative ventilatory management and clinical outcomes. RESULTS A total of 9864 patients fulfilled the inclusion criteria. The incidence of patients at increased risk was 28.4%. The most frequently chosen tidal volume (VT) size was 500 ml, or 7 to 9 ml kg1 predicted body weight, slightly lower in patients at increased risk of PPCs. Levels of positive end-expiratory pressure (PEEP) were slightly higher in patients at increased risk of PPCs, with 14.3% receiving more than 5 cmH2O PEEP compared with 7.6% in patients at low risk of PPCs (P < 0.001). Patients with a predicted preoperative increased risk of PPCs developed PPCs more frequently: 19 versus 7%, relative risk (RR) 3.16 (95% confidence interval 2.76 to 3.61), P < 0.001) and had longer hospital stays. The only ventilatory factor associated with the occurrence of PPCs was the peak pressure. CONCLUSION The incidence of patients with a predicted increased risk of PPCs is high. A large proportion of patients receive high VT and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome

Is Urban Regeneration possible without gentrification? A proposal of a social condenser for Alegria's street, Lisbon

The period of Covid-19 has exposed the contradictions of Lisbon´s urban economic recovery model of the last decade in the aftermath of the crisis of 2008-2009, based on the financialization of real estate and the “touristification” of the territory, generating gentrification, façadism, and residential and functional segregation. In this study, we make a spatial cut in the historic center of Lisbon, namely, at Rua da Alegria and we aim to demonstrate how, through the prototype of a “social district condenser”, it will be possible to produce urban regeneration, preserving at the same time the identity of the historic center and avoiding and mitigating the consequences of those processes