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Le divertissement au travail : un obstacle à la cohésion de groupe
No full textInternational audienceCette recherche explore l’influence négative du divertissement au travail sur la cohésion de groupe. Une observation sur le terrain, une analyse documentaire et des entretiens semi- directifs menés dans une entreprise organisant des activités divertissantes ont révélé que le choix inapproprié des activités, les commérages, la consommation d’alcool, les perceptions d’inégalités entre unités et le sentiment d’être manipulé peuvent nuire à la cohésion de groupe
Femtosecond non-adiabatic confinement of molecular dication yield
No full textInternational audienceDoubly charged molecular cations often carry signatures of electronic correlation and electron–nuclear entanglement present in the parent cation. Here, we produce ethylene dications using a combination of an extreme ultraviolet pump and near-infrared probe pulses, observing a peak in the dication yield at a pump–probe delay of approximately 15 fs. Ab-initio calculations, which explicitly take into account coupled electron–nuclear dynamics induced by the pump and the multiphoton nature of the probe-induced ionization step, reproduced the observed delay in the yield. It originates from resonant enhancement of the multiphoton ionization of the electronically excited ethylene cation as the carbon–carbon double bond expands. However, this effect is tempered by rapid nonadiabatic relaxation of the excited ionic states. Our results suggest a general mechanism whereby ultrafast nonadiabatic relaxation of a molecular ion can compete with its strong-field ionization rate, confining the dication yield to a narrow temporal window of a few femtoseconds
Photochemical reactivity and fate of the toxic transformation product of naproxen in water
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Crystallographic Fragment Screening with CK2α’, an Isoform of Human Protein Kinase CK2 Catalytic Subunit, and Its Use to Obtain a CK2α’/Heparin Complex Structure
No full textInternational audienceCK2α and CK2α', two paralogous members of the human kinome, are catalytic subunits of protein kinase CK2. Together with the regulatory subunit CK2β, they form heterotetrameric holoenzymes. CK2 is the subject of efforts to develop effective and selective inhibitors. For this, secondary binding sites remote from the canonical ATP/GTP cavity are critical. A crystallographic fragment screening with CK2α' crystals and an established molecular fragment collection was performed to identify new ligands at known or novel sites. It resulted in fourteen CK2α'/fragment structures. Five fragments were found at the CK2β interface of CK2α' and three fragments at the established αD pocket, which exhibits subtle differences between CK2α and CK2α'; comparative co-crystallisations with CK2α showed that one of them binds to the αD pocket of CK2α' exclusively. No fragments bound at the substrate-binding region of CK2α', but a CK2α' structure with dp10, a decameric section of the substrate-competitive inhibitor heparin, and the indenoindole-type ATP-competitive inhibitor 4w was determined. A comparison with a published CK2α/dp10 structure revealed features consistent with reports about substrate specificity differences between the isoenzymes: dp10 binds to CK2α' and CK2α with opposite strand orientations, and the local conformations of the isoenzymes in the helix αD region are significantly different.</div
Synthesis of Indeno[1,2-b]indole-9,10-diones: Toward a One-Pot, Two-Step Reaction
No full textInternational audienceAbstract Indeno[1,2-b]indole was shown to be a key scaffold for the design of new bioactive molecules in oncology (e.g., inhibitors of protein kinase CK2 and inhibitors of the breast cancer resistance protein ABCG2). Depending on the synthetic route chosen, a large variety of specific functionalizations can be achieved. In order to develop new indeno[1,2-b]indole-9,10-diones as CK2 inhibitors, four functionalized indeno[1,2-b]indoles were synthesized using a two-step reaction described in the literature. Given that the reactions reported led to unexpected results, such as incomplete reaction progress, very low yields, and significant formation of by-products, we first optimized the quantities of reagents (AcOH and N,N,N′,N′-tetraethyl sulfurous diamide) and the types of solvents used in the synthetic steps. Then, based on these optimal reaction conditions, a one-pot, two-step reaction was developed to maximize yields and standardize the process, thereby making it more convenient and straightforward
Oxidative and Inflammatory Mechanisms Induced by Intermittent Hypoxia Leading to Vascular Alterations in Rodents: A Systematic Review and Meta‐Analysis
No full textInternational audienceObjectives Obstructive sleep apnea (OSA) and the related intermittent hypoxia (IH) are recognized as major cardiovascular risk factors. In a previous meta‐analysis, we confirmed the impact of IH on structural and functional remodeling of vessels in rodent models of IH. Here, we conducted a systematic review and meta‐analysis to investigate the molecular mechanisms related to vascular remodeling induced by IH and to analyze the impacts of patterns of exposure on the effect of IH. Methods We searched PubMed, Web of Science, and EMBASE and included 52 articles, among them 44 concerning wild type (WT) rodents and eight concerning apolipoprotein E knockout (ApoE −/− ) mice. We used standardized mean difference (SMD) to compare results between studies. A hypoxic score was designed and calculated, and metaregressions were performed to explore the impact of IH exposure parameters on the selected outcomes. Results IH induced an increase in oxidative stress, inflammation markers, leucocyte infiltration, and apoptosis, and a decrease in endothelial nitric oxide synthase (eNOS) expression and activity in arteries of WT mice. In metaregressions, inflammation and oxidative stress markers were associated with total duration of IH exposure, and eNOS was associated with hypoxic score. In ApoE −/− mice, inflammation markers were significantly increased in atherosclerotic plaques, but leukocyte infiltration and oxidative stress were not modified by IH. Rodent characteristics had only few impacts on the outcomes. Conclusions Our meta‐analysis confirms that IH, independently of measured confounders, has a major impact on oxido‐inflammatory mechanisms in vessels, and that the duration of IH can modulate these effects. Our findings strengthen our understanding of molecular mechanisms associated with vascular alterations in IH/OSA
Sait-on mesurer les effets de la gratuité des transports en commun ?
No full textInternational audienceThe introduction of fully fare-free public transport has failed to convince many transport specialists. According to Félicien Boiron, focusing the analysis of such policies on criteria of “effectiveness” serves to legitimize certain norms in the making of public transport policies.La gratuité totale des transports en commun convainc peu les spécialistes du sujet. Selon Félicien Boiron, centrer l’évaluation sur des critères d’« efficacité » de la mesure légitime certaines normes dans la fabrique des politiques publiques de transport
Scale-Equivariant Imaging: Self-Supervised Learning for Image Super-Resolution and Deblurring
No full textSelf-supervised methods have recently proved to be nearly as effective as supervised ones in various imaging inverse problems, paving the way for learning-based approaches in scientific and medical imaging applications where ground truth data is hard or expensive to obtain. These methods critically rely on invariance to translations and/or rotations of the image distribution to learn from incomplete measurement data alone. However, existing approaches fail to obtain competitive performances in the problems of image super-resolution and deblurring, which play a key role in most imaging systems. In this work, we show that invariance to roto-translations is insufficient to learn from measurements that only contain low-frequency information. Instead, we propose scale-equivariant imaging, a new self-supervised approach that leverages the fact that many image distributions are approximately scale-invariant, enabling the recovery of high-frequency information lost in the measurement process. We demonstrate throughout a series of experiments on real datasets that the proposed method outperforms other self-supervised approaches, and obtains performances on par with fully supervised learning
Assessing Thermodynamic Equilibrium and Corrective approach for VOCs Adsorption on Microporous Activated Carbon
No full textRMN+ING+CDA:THM:CCL:DFANational audienceAdvances in air purification increasingly rely on high-performing adsorbents for volatile organic compounds (VOC) removal, with material innovations in microporous and mesoporous frameworks1. However, accurately characterizing adsorbent affinity for VOCs at low concentration remains challenging due to extremely slow adsorption kinetics in highly confining ultramicroporous solids. In this context, accurately determining the Henry constant KH for VOC adsorption in microporous solids at low pressures is limited by difficulties in reaching thermodynamic equilibrium in standard experimental methods. Here, a thermodynamically grounded three-step methodology is introduced for reliable estimation of the Henry constant in such diffusion-limited systems. In practice, this strategy is illustrated by considering cyclohexane adsorption on commercial activated carbon (AC). The approach involves (1) measuring adsorption isotherms at elevated temperatures (which ensure that thermodynamic equilibrium is reached), (2) extrapolating to the target temperature via Polanyi’s adsorption potential theory2 (Fig 1) , and (3) finally deriving KH from the recalculated low-pressure region. This method allows reconstructing the adsorption isotherm. This strategy, which is validated by showing that the adsorption isotherms match those obtained from independent breakthrough experiments, reveals systematic underestimation of adsorption at low pressure with standard protocols (up to a 15-fold difference in KH). This study demonstrates how corrections based on Polanyi’s adsorption potential theory allow overcoming equilibrium limitations, outperforming both measurements and kinetic-based protocols alone