Optimization of immunity testings in a mode tuned reverberation chamber with Monte Carlo simulations

International audienceIn this article, we show that an estimation of the probability of failure of a device under test can provide an accurate information about its susceptibility. Monte Carlo simulations give statistical results on the quality of the estimation and a virtual equipment under test is tested numerically with this approach. We propose a modus operandi that reduces the duration of the testing and in-creases its accuracy. Measurements on a real device confirm our predictions

A Probabilistic Approach to Susceptibility Measurement in a Reverberation Chamber

International audienceIn this article, we propose an alternative approach for measuring the susceptibility level of an equipment under test in a reverberation chamber. Instead of using a statistical estimation of the maximum, our estimation is based on an esti- mation of the probability of failure of the equipment under test. We show through Monte Carlo simulations that the probability of failure of an equipment under test allows to predict with a good accuracy its susceptibility level. An experimental validation with a simple equipment under test shows that the susceptibility levels measured in a reverberation chamber are consistent with measurements performed in a GTEM cell

A Binomial Model for Radiated Immunity Measurements

International audienceWe propose a statistical analysis of immunity testing in EMC based on binomial distributions. This approach aims at extracting the immunity properties of a device from its probability of failure during a test. We show that under certain conditions, this approach can be applied to plane wave testing environments and reverberation chambers. This approach allows one to control the uncertainty of the immunity level estimation and to reduce the duration of a test by both reducing significantly the number of observations needed to reach a given uncertainty budget and giving an optimal number of power level tested. We show the benefits of such an approach for immunity testing and we present some experimental results

Studying the pulse regime in a reverberation chamber with a model based on image theory

6 pages - WOSInternational audienceIn this article, we propose a time-domain model of a reverberation chamber (RC). This very straightforward model based upon image theory (IT) allows to simulate the behavior of a reverberation chamber in the pulse regime. After a brief introduction of the model, results with different pulse lengths and different loading configurations are presented and compared to measurements made in the reverberation chamber of our laboratory

Fine Analysis of the Behavior of a Reverberation Chamber in the Frequency Domain with a Model Based Upon Image Theory

International audienceIn this article, we propose a model based upon image theory (IT). This very straightforward model designed initially as a time domain model carry the physics of a reverberation chamber (RC) and is able to simulate its behavior in the frequency domain. Simulation results obtained with this model are compared with measurements in the reverberation chamber of our laboratory and an electric field imbalance observed in our reverberation chamber is reproduced with our model

Modélisation d'une chambre réverbérante basée sur la théorie des image: étude en régime pulsé

Résumé et PosterA poster presentation about a reverberation chamber model that uses image theory

Reverberation Chamber Modeling Based on Image Theory: Investigation in the Pulse Regime

WOSInternational audienceIn this paper we propose a straight- forward 3D time domain model of a reverberation chamber (RC) based on image theory. This model allows one to describe the earliest moments of an arbi- trary waveform in an RC. Time domain and frequency domain results from this model are analyzed and compared with measurements conducted in a reverberation chamber

Ventriculo-arterial (un)coupling in septic shock: Impact of current and upcoming hemodynamic drugs

Sepsis is an archetype of distributive shock and combines different levels of alterations in preload, afterload, and often cardiac contractility. The use of hemodynamic drugs has evolved over the past few years, along with the invasive and non-invasive tools used to measure these components in real time. However, none of them is impeccable, which is why the mortality of septic shock remains too high. The concept of ventriculo-arterial coupling (VAC) allows for the integration of these three fundamental macroscopic hemodynamic components. In this mini review, we discuss the knowledge, tools, and limitations of VAC measurement, along with the evidence supporting ventriculo-arterial uncoupling in septic shock. Finally, the impact of recommended hemodynamic drugs and molecules on VAC is detailed

Association between volume of lung damage and endoplasmic reticulum stress expression among severe COVID-19 ICU patients

IntroductionLinks have been established between SARS-CoV-2 and endoplasmic reticulum stress (ERS). However, the relationships between inflammation, ERS, and the volume of organ damage are not well known in humans. The aim of this study was to explore whether ERS explains lung damage volume (LDV) among COVID-19 patients admitted to the intensive care unit (ICU).Materials and methodsWe conducted a single-center retrospective study (ancillary analysis of a prospective cohort) including severe COVID-19 ICU patients who had a chest computed tomography (CT) scan 24 h before/after admission to assess LDV. We performed two multivariate linear regression models to identify factors associated with plasma levels of 78 kDa-Glucose-Regulated Protein (GRP78; ERS marker) and Interleukin-6 (IL-6; inflammation marker) at admission.ResultsAmong 63 patients analyzed, GRP78 plasma level was associated with LDV in both multivariate models (β = 22.23 [4.08;40.38]; p = 0.0179, β = 20.47 [0.74;40.20]; p = 0.0423) but not with organ failure (Sequential Organ Failure Assessment (SOFA) score) at admission (r = 0.03 [−0.22;0.28]; p = 0.2559). GRP78 plasma level was lower among ICU survivors (1539.4 [1139.2;1941.1] vs. 1714.2 [1555.2;2579.1] pg./mL. respectively; p = 0.0297). IL-6 plasma level was associated with SOFA score at admission in both multivariate models (β = 136.60 [65.50;207.70]; p = 0.0003, β = 193.70 [116.60;270.90]; p < 0.0001) but not with LDV (r = 0.13 [−0.14;0.39]; p = 0.3219). IL-6 plasma level was not different between ICU survivors and non-survivors (12.2 [6.0;43.7] vs. 30.4 [12.9;69.7] pg./mL. respectively; p = 0.1857). There was no correlation between GRP78 and IL-6 plasma levels (r = 0.13 [−0.13;0.37]; p = 0.3106).ConclusionAmong severe COVID-19 patients, ERS was associated with LDV but not with systemic inflammation, while systemic inflammation was associated with organ failure but not with LDV