ARE AB INITIO QUANTUM CHEMISTRY METHODS ABLE TO PREDICT VIBRATIONAL STATES UP TO THE DISSOCIATION LIMIT FOR MULTI-ELECTRON MOLECULES CLOSE TO SPECTROSCOPIC ACCURACY?

Author Institution: Eotvos Lorand University, Budapest, Hungary; Slovak University of Technology, Trnava, Slovak Republic; Reims University, Reims, FranceThe aim of the study was to explore the limits of initio methods towards the description of excited vibrational levels up to the dissociation limit for molecules having more than two electrons. To this end a high level {\it ab initio} potential energy function was constructed for the four-electron LiH molecule in order to accurately predict a complete set of bound vibrational levels corresponding to the electronic ground state. It was composed from: a) an {\it ab initio} non-relativistic potential obtained at the MR-CISD level including size-extensivity corrections and quintuple-sextuple $\zeta$ extrapolation of the basis, b) MVD (Mass-velocity-Darwin) relativistic corrections obtained at icMR-CISD/cc-pwCV5Z level, and c) DBOC (Diagonal Born-Oppenheimer correction) obtained at the MR-CISD/cc-pwCVTZ level. Finally, the importance of non-adiabatic effects was also tested by using atomic masses in the vibrational kinetic energy operator and by calculation of non-adiabatic coupling by {\it ab initio} methods. The calculated vibrational levels were compared with those obtained from experimental data [J.A. Coxon and C.S. Dickinson, \textit{J. Chem. Phys.}, 2004, \textbf{121}, 9378]. Our best estimate of the potential curve results in vibrational energies with a RMS deviation of only $\sim$1 \wn\ for the entire set of all empirically determined vibrational levels known so far. These results represent a drastic improvement over previous theoretical predictions of vibrational levels of $^7$LiH up to dissociation, $D_0$, which was predicted to be 19594 cm$^{-1}$. In addition, rotational levels have also been calculated. The RMS deviation between our ab initio calculations and empirical results by Coxon and Dickinson for rotational spacings $\Delta E = E(v, J = 1)-E(v, J = 0)$ over all available vibrational states of $^7$LiH from $v = 0$ to $v= 20$ is 0.010 \wn\ (with nuclear masses) and 0.006 \wn\ (with atomic masses). Note that for high vibrational states with $v > 6$ this falls within the uncertainty of the measurements

Etude des contributions aux surfaces de potentiel et couplages non-adiabatiques par calculs ab initio de structures électroniques et mise aux points des Hamiltoniens effectifs pour les prédictions vibrationnelles : applications aux molécules LiH, H+3 et PH3

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Readout Circuit Implemented on PCB-Level for Embedded CNT Sensors

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Using X-ray imaging for the study of crack development in solder reliability testing

The possibility of monitoring the progressive damage and cracking in solder joints is investigated through a non-destructive method. As X-ray 3D Computed Tomography is known to require small sample dimensions in order to ensure a good resolution, Computed Laminography was used to get a high-resolution top view of various types of solder joints located on a large printed circuit board. In a first step, the assemblies were cross-sectioned after X-ray imaging in order to verify the findings and confirm the crack morphology. Then, by avoiding a destructive sample preparation step, it was possible to identify in a single sample the effects of solder fatigue during a standard reliability test. Firstly, multiple crack initiation sites could be highlighted in a single X-ray analysis. Moreover, the study gave an interesting insight of the time evolution of voids in solder joints. X-ray laminography produces 3D-like images that contain more information than a conventional cross section. By improving the recognition of horizontal cracks in this unusual point of view of solder joints, the refinement of this imaging and monitoring method can result in a real progress in failure analysis time and efficiency

High-Dose Dexamethasone and Oxygen Support Strategies in Intensive Care Unit Patients With Severe COVID-19 Acute Hypoxemic Respiratory Failure

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Effect of Tocilizumab vs Usual Care in Adults Hospitalized With COVID-19 and Moderate or Severe Pneumonia

International audienceImportance Severe pneumonia with hyperinflammation and elevated interleukin-6 is a common presentation of coronavirus disease 2019 (COVID-19).Objective To determine whether tocilizumab (TCZ) improves outcomes of patients hospitalized with moderate-to-severe COVID-19 pneumonia.Design, Setting, and Particpants This cohort-embedded, investigator-initiated, multicenter, open-label, bayesian randomized clinical trial investigating patients with COVID-19 and moderate or severe pneumonia requiring at least 3 L/min of oxygen but without ventilation or admission to the intensive care unit was conducted between March 31, 2020, to April 18, 2020, with follow-up through 28 days. Patients were recruited from 9 university hospitals in France. Analyses were performed on an intention-to-treat basis with no correction for multiplicity for secondary outcomes.Interventions Patients were randomly assigned to receive TCZ, 8 mg/kg, intravenously plus usual care on day 1 and on day 3 if clinically indicated (TCZ group) or to receive usual care alone (UC group). Usual care included antibiotic agents, antiviral agents, corticosteroids, vasopressor support, and anticoagulants.Main Outcomes and Measures Primary outcomes were scores higher than 5 on the World Health Organization 10-point Clinical Progression Scale (WHO-CPS) on day 4 and survival without need of ventilation (including noninvasive ventilation) at day 14. Secondary outcomes were clinical status assessed with the WHO-CPS scores at day 7 and day 14, overall survival, time to discharge, time to oxygen supply independency, biological factors such as C-reactive protein level, and adverse events.Results Of 131 patients, 64 patients were randomly assigned to the TCZ group and 67 to UC group; 1 patient in the TCZ group withdrew consent and was not included in the analysis. Of the 130 patients, 42 were women (32%), and median (interquartile range) age was 64 (57.1-74.3) years. In the TCZ group, 12 patients had a WHO-CPS score greater than 5 at day 4 vs 19 in the UC group (median posterior absolute risk difference [ARD] −9.0%; 90% credible interval [CrI], −21.0 to 3.1), with a posterior probability of negative ARD of 89.0% not achieving the 95% predefined efficacy threshold. At day 14, 12% (95% CI −28% to 4%) fewer patients needed noninvasive ventilation (NIV) or mechanical ventilation (MV) or died in the TCZ group than in the UC group (24% vs 36%, median posterior hazard ratio [HR] 0.58; 90% CrI, 0.33-1.00), with a posterior probability of HR less than 1 of 95.0%, achieving the predefined efficacy threshold. The HR for MV or death was 0.58 (90% CrI, 0.30 to 1.09). At day 28, 7 patients had died in the TCZ group and 8 in the UC group (adjusted HR, 0.92; 95% CI 0.33-2.53). Serious adverse events occurred in 20 (32%) patients in the TCZ group and 29 (43%) in the UC group (P = .21).Conclusions and Relevance In this randomized clinical trial of patients with COVID-19 and pneumonia requiring oxygen support but not admitted to the intensive care unit, TCZ did not reduce WHO-CPS scores lower than 5 at day 4 but might have reduced the risk of NIV, MV, or death by day 14. No difference on day 28 mortality was found. Further studies are necessary for confirming these preliminary results.Trial Registration ClinicalTrials.gov Identifier: NCT0433180