H2_2 Double Ionization with Few-Cycle Laser Pulses

International audienceThe temporal dynamics of double ionization of H$_2$ has been investigated both experimentally and theoretically with few-cycle laser pulses. The main observables are the proton spectra associated to the H$^+$ + H$^+$ fragmentation channel. The model is based on the time-dependent Schrödinger equation and treats on the same level the electronic and nuclear coordinates. Therefore it allows to follow the ultrafast nuclear dynamics as a function of the laser pulse duration, carrier-envelope phase offset and peak intensity. We mainly report results in the sequential double ionization regime above 2 x 10$^{14}$ W/cm$^{-2}$. The proton spectra are shifted to higher energies as the pulse duration is reduced from 40fs down to 10fs. The good agreement between the model predictions and the experimental data at 10fs permits a theoretical study with pulse durations down to a few femtoseconds. We demonstrate the very fast nuclear dynamics of the H$_2^+$ ion for a pulse duration as short as 1fs between the two ionization events giving respectively H$_2^+$ from H$_2$ and H$^+$ + H$^+$ from H$_2^+$. Carrier-envelope phase offset only plays a significant role for pulse durations shorter than 4fs. At 10fs, the laser intensity dependence of the proton spectra is fairly well reproduced by the model

Ultrafast electro-nuclear dynamics of H2 double ionization

The ultrafast electronic and nuclear dynamics of H2 laser-induced double ionization is studied using a time-dependent wave packet approach that goes beyond the fixed nuclei approximation. The double ionization pathways are analyzed by following the evolution of the total wave function during and after the pulse. The rescattering of the first ionized electron produces a coherent superposition of excited molecular states which presents a pronounced transient H+H- character. This attosecond excitation is followed by field-induced double ionization and by the formation of short-lived autoionizing states which decay via double ionization. These two double ionization mechanisms may be identified by their signature imprinted in the kinetic-energy distribution of the ejected protons

Obstructive hydrocephalus and intracerebral mass secondary to Epicoccum nigrum

Here we report a case of a 14-week-old girl with a history of intrauterine drug exposure and hypoxic ischemic encephalopathy secondary to cardiac arrest requiring prolonged resuscitation at birth presented with irritability and a bulging anterior fontanelle. After neurosurgical resection, pathologic examination showed fungal hyphae, an

Flood frequency analysis at ungauged catchments with the GAM and MARS approaches in the Montreal region, Canada

Regional frequency analysis (RFA) aims to estimate quantiles of extreme hydrological variables (e.g. floods or low-flows) at sites where little or no hydrological data is available. This information is of interest for the optimal planning and management of water resources. A number of regional estimation models are evaluated and compared in this study and then used for regional estimation of flood quantiles at ungauged catchments located in the Montreal region in southern Quebec, Canada. In this study, two neighborhood approaches using canonical correlation analysis (CCA) and the region of influence (ROI) method are applied to delineate homogenous regions. Three regression methods namely log-linear regression model (LLRM), generalized additive models (GAM), and multivariate adaptive regression splines (MARS), recently introduced in the RFA context, are considered for regional estimation. These models are also applied considering all stations (ALL). The considered models, especially MARS, have never been used previously in a concrete application. Results indicate that MARS and GAM have comparable predictive performances, especially when applied with the whole dataset. Results also show that MARS used in combination with the CCA approach provide improved performances compared to all considered regional approaches. This may reflect the flexibility of the combination of these two approaches, their robustness, and their ability to better reproduce the hydrological phenomena, especially in real-world conditions when limited data are available

All-optical matter-wave lens using time-averaged potentials

The precision of matter-wave sensors benefits from interrogating large-particle-number atomic ensembles at high cycle rates. Quantum-degenerate gases with their low effective temperatures allow for constraining systematic errors towards highest accuracy, but their production by evaporative cooling is costly with regard to both atom number and cycle rate. In this work, we report on the creation of cold matter-waves using a crossed optical dipole trap and shaping them by means of an all-optical matter-wave lens. We demonstrate the trade off between lowering the residual kinetic energy and increasing the atom number by reducing the duration of evaporative cooling and estimate the corresponding performance gain in matter-wave sensors. Our method is implemented using time-averaged optical potentials and hence easily applicable in optical dipole trapping setups. © 2022, The Author(s)

Carbohydrate-based peptidomimetics targeting neuropilin-1: synthesis, molecular docking study and in vitro biological activities

International audienceNeuropilin-1 (NRP-1), a transmembrane glycoprotein acting as a co-receptor of VEGF-A, is expressed by cancer and angiogenic endothelial cells and is involved in the angiogenesis process. Taking advantage of functionalities and stereodiversities of sugar derivatives, the design and the synthesis of carbohydrate based peptidomimetics are here described. One of these compounds (56) demonstrated inhibition of VEGF-A165 binding to NRP-1 (IC50 = 39 μM) and specificity for NRP-1 over VEGF-R2. Biological evaluations were performed on human umbilical vein endothelial cells (HUVECs) through activation of downstream proteins (AKT and ERK phosphorylation), viability/proliferation assays and in vitro measurements of anti-angiogenic abilities

Interacting quantum mixtures for precision atom interferometry

We present a source engineering concept for a binary quantum mixture suitable as input for differential, precision atom interferometry with drift times of several seconds. To solve the non-linear dynamics of the mixture, we develop a set of scaling approach equations and verify their validity contrasting it to the one of a system of coupled Gross-Pitaevskii equations. This scaling approach is a generalization of the standard approach commonly used for single species. Its validity range is discussed with respect to intra- and inter-species interaction regimes. We propose a multi-stage, non-linear atomic lens sequence to simultaneously create dual ensembles with ultra-slow kinetic expansion energies, below 15 pK. Our scheme has the advantage of mitigating wave front aberrations, a leading systematic effect in precision atom interferometry

Heat-related mortality prediction using low-frequency climate oscillation indices: Case studies of the cities of Montréal and Québec, Canada

Background: Heat-related mortality is an increasingly important public health burden that is expected to worsen with climate change. In addition to long-term trends, there are also interannual variations in heat-related mortality that are of interest for efficient planning of health services. Large-scale climate patterns have an important influence on summer weather and therefore constitute important tools to understand and predict the variations in heat-related mortality. Methods: In this article, we propose to model summer heat-related mortality using seven climate indices through a two-stage analysis using data covering the period 1981–2018 in two metropolitan areas of the province of Québec (Canada): Montréal and Québec. In the first stage, heat attributable fractions are estimated through a time series regression design and distributed lag nonlinear specification. We consider different definitions of heat. In the second stage, estimated attributable fractions are predicted using climate index curves through a functional linear regression model. Results: Results indicate that the Atlantic Multidecadal Oscillation is the best predictor of heat-related mortality in both Montréal and Québec and that it can predict up to 20% of the interannual variability. Conclusion: We found evidence that one climate index is predictive of summer heat-related mortality. More research is needed with longer time series and in different spatial contexts. The proposed analysis and the results may nonetheless help public health authorities plan for future mortality related to summer heat

Cross-validation of ELISA and a portable surface plasmon resonance instrument for IgG antibody serology with SARS-CoV-2 positive individuals.

We report on the development of surface plasmon resonance (SPR) sensors and matching ELISAs for the detection of nucleocapsid and spike antibodies specific to the novel coronavirus 2019 (SARS-CoV-2) in human serum, plasma and dried blood spots (DBS)

Adverse events in families with hypertrophic or dilated cardiomyopathy and mutations in the MYBPC3 gene

<p>Abstract</p> <p>Background</p> <p>Mutations in <it>MYBPC3 </it>encoding myosin binding protein C belong to the most frequent causes of hypertrophic cardiomyopathy (HCM) and may also lead to dilated cardiomyopathy (DCM). <it>MYBPC3 </it>mutations initially were considered to cause a benign form of HCM. The aim of this study was to examine the clinical outcome of patients and their relatives with 18 different <it>MYBPC3 </it>mutations.</p> <p>Methods</p> <p>87 patients with HCM and 71 patients with DCM were screened for <it>MYBPC3 </it>mutations by denaturing gradient gel electrophoresis and sequencing. Close relatives of mutation carriers were genotyped for the respective mutation. Relatives with mutation were then evaluated by echocardiography and magnetic resonance imaging. A detailed family history regarding adverse clinical events was recorded.</p> <p>Results</p> <p>In 16 HCM (18.4%) and two DCM (2.8%) index patients a mutation was detected. Seven mutations were novel. Mutation carriers exhibited no additional mutations in genes <it>MYH7</it>, <it>TNNT2</it>, <it>TNNI3</it>, <it>ACTC </it>and <it>TPM1</it>. Including relatives of twelve families, a total number of 42 mutation carriers was identified of which eleven (26.2%) had at least one adverse event. Considering the twelve families and six single patients with mutations, 45 individuals with cardiomyopathy and nine with borderline phenotype were identified. Among the 45 patients, 23 (51.1%) suffered from an adverse event. In eleven patients of seven families an unexplained sudden death was reported at the age between 13 and 67 years. Stroke or a transient ischemic attack occurred in six patients of five families. At least one adverse event occurred in eleven of twelve families.</p> <p>Conclusion</p> <p><it>MYBPC3 </it>mutations can be associated with cardiac events such as progressive heart failure, stroke and sudden death even at younger age. Therefore, patients with <it>MYBPC3 </it>mutations require thorough clinical risk assessment.</p