Cross metathesis of bio-sourced fatty nitriles with acrylonitrile.

International audienceWe report the cross metathesis of two olefinic partners contg. different types of nitrile functionality. Thus, cross metathesis of fatty nitriles with acrylonitrile have been achieved with olefin metathesis ruthenium catalysts. 10-Undecenenitrile provides 2-dodecenedinitrile with a high turnover no. of 13,280 in the green solvent, di-Et carbonate. Cross metathesis with the internal carbon-carbon double bond of oleonitrile gave the expected products, and the cleavage of the internal double bond proved to be more difficult probably owing to faster catalyst decomposition

Boosting Higher-Order Correlation Attacks by Dimensionality Reduction

Multi-variate side-channel attacks allow to break higher-order masking protections by combining several leakage samples. But how to optimally extract all the information contained in all possible $d$-tuples of points? In this article, we introduce preprocessing tools that answer this question. We first show that maximizing the higher-order CPA coefficient is equivalent to finding the maximum of the covariance. We apply this equivalence to the problem of trace dimensionality reduction by linear combination of its samples. Then we establish the link between this problem and the Principal Component Analysis. In a second step we present the optimal solution for the problem of maximizing the covariance. We also theoretically and empirically compare these methods. We finally apply them on real measurements, publicly available under the DPA Contest v4, to evaluate how the proposed techniques improve the second-order CPA (2O-CPA)

Security evaluation against side-channel analysis at compilation time

Masking countermeasure is implemented to thwart side-channel attacks. The maturity of high-order masking schemes has reached the level where the concepts are sound and proven. For instance, Rivain and Prouff proposed a full-fledged AES at CHES 2010. Some non-trivial fixes regarding refresh functions were needed though. Now, industry is adopting such solutions, and for the sake of both quality and certification requirements, masked cryptographic code shall be checked for correctness using the same model as that of the the theoretical protection rationale (for instance the probing leakage model). Seminal work has been initiated by Barthe et al. at EUROCRYPT 2015 for automated verification at higher orders on concrete implementations. In this paper, we build on this work to actually perform verification from within a compiler, so as to enable timely feedback to the developer. Precisely, our methodology enables to provide the actual security order of the code at the intermediate representation (IR) level, thereby identifying possible flaws (owing either to source code errors or to compiler optimizations). Second, our methodology allows for an exploitability analysis of the analysed IR code. In this respect, we formally handle all the symbolic expressions in the static single assignment (SSA) representation to build the optimal distinguisher function. This enables to evaluate the most powerful attack, which is not only function of the masking order $d$, but also on the number of leaking samples and of the expressions (e.g., linear vs non-linear leakages). This scheme allows to evaluate the correctness of a masked cryptographic code, and also its actual security in terms of number of traces in a given deployment context (characterized by a leakage model of the target CPU and the signal-to-noise ratio of the platform)

Time-Frequency Analysis for Second-Order Attacks

Second-order side-channel attacks are used to break first-order masking protections. A practical reason which often limits the efficiency of second-order attacks is the temporal localisation of the leaking samples. Several leakage samples must be combined which means high computational power. For second-order attacks, the computational complexity is quadratic. At CHES \u2704, Waddle and Wagner introduced attacks with complexity $\mathcal{O}(n \log_2 n)$ on hardware traces, where $n$ is the window size, by working on traces auto-correlation. Nonetheless, the two samples must belong to the same window which is (normally) not the case for software implementations. In this article, we introduce preprocessing tools that improve the efficiency of bi-variate attacks (while keeping a complexity of $\mathcal{O}(n \log_2 n)$), even if the two samples that leak are far away one from the other (as in software). We put forward two main improvements. Firstly, we introduce a method to avoid loosing the phase information. Next, we empirically notice that keeping the analysis in the frequency domain can be beneficial for the attack. We apply these attacks in practice on real measurements, publicly available under the DPA Contest v4, to evaluate the proposed techniques. An attack using a window as large as 4000 points is able to reveal the key in only 3000 traces

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Bilan concernant l'état bucco-dentaire de sujets porteurs de prothèses, résidant dans une maison de retraite

Le vieillissement a des conséquences bucco-dentaires d'ordre fonctionnel et esthétique avec un retentissement psycho affectif important. Les tissus bucco-dentaires subissent des transformations se traduisant par un moindre pouvoir réparateur, une résorption osseuse, une diminution du flux salivaire associées à un édentement croissant. Le manque d'hygiène et de soins dentaires viennent souvent aggraver cet état bucco-dentaire de la personne âgée en la conduisant souvent après différentes étapes, à l'édentement total. Après un rappel sur ces différentes répercussions, nous rapportons les résultats d'un bilan bucco-dentaire réalisé dans une maison de retraite d'Angers à l'aide d'un questionnaire spécifique.NANTES-BU Médecine pharmacie (441092101) / SudocPARIS-BIUM (751062103) / SudocLILLE2-UFR Odontologie (593502202) / SudocSudocFranceF

Ruthenium catalyzed ethenolysis of renewable oleonitrile

International audienc

Tertiary 3-Aminopropenones and 3-Aminopropenoates : Their preparation, with and without Lewis Acids, from Secondary Amines and 1,3 Diketo Compounds

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