Publications scientifiques de l'Université de Reims Champagne-Ardenne
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Modulation of platelet interaction with collagen by carbamylation, a NEPTM occurring during pathophysiological vascular aging
No full textInternational audienceINTRODUCTION - Vascular aging is associated with extensive extracellular matrix (ECM) remodelling and leads to arterial wall stiffening and thickening. Due to their long half-life, ECM proteins including collagens are exposed to molecular aging characterized by non-enzymatic post-translational modifications (NEPTMs) that progressively alter their structure and function. One of these NEPTMs, carbamylation, consists of binding of isocyanic acid (mainly coming from urea dissociation) to amino groups of proteins. This NEPTM is exacerbated during chronic kidney disease (CKD) due to hyperuremia. CKD leads to cardiovascular and thromboembolic complications, and paradoxically, to an increased hemorrhagic risk. Different risk factors have been reported in the literature such as the accumulation of uremic toxins, chronic inflammation, endothelial dysfunction, hypercoagulability or anemia. However, whether carbamylation of collagen, the main thrombogenic ECM component of the vascular subendothelium, may impact hemostasis and thrombosis, has never been investigated so far. MATERIALS & METHODS - Rat type I collagen was carbamylated with sodium cyanate and the impact of collagen carbamylation on plasma von Willebrand factor (VWF) binding, platelet adhesion under static and flow conditions, platelet signaling and platelet aggregation was evaluated. RESULTS – Carbamylated collagen reduces by two-fold its ability to bind plasma VWF compared to control collagen and leads to a drastic decrease by more than 80% of platelet interaction with collagen after 6 min perfusion (human whole blood, 1,500 s-1). Washed platelet adhesion to carbamylated collagen under static condition was slightly reduced after 30 min and associated with reduced platelet activation and signaling compared to control collagen. Finally, human washed platelet aggregation was also strongly decreased by carbamylated collagen. Impact of ECM carbamylation in in vivo models of hemostasis and thrombosis is currently under investigation.CONCLUSION - These results suggest that carbamylation of collagen may strongly affect platelet interaction with vascular subendothelium and play a critical role in hemorrhagic/thrombotic complications associated with CKD
Les débats parlementaires sur la loi « climat et résilience » : Décarbonation : un discours de la méthode différencié
No full textInternational audienceNotre étude porte sur les débats parlementaires relatif au projet de loi « climat et résilience » qui entend réduire l’empreinte carbone. Elle vise à décrire et analyser les divers dispositifs symboliques, les référents idéologiques mobilisés par les parlementaires, les argumentaires développés à propos de la volonté de décarbonation que souhaite mener le gouvernement dans le cadre dudit projet de loi en centrant notre étude sur les discussions générales. La droite et la majorité gouvernementale structurent leur discours autour de la pensée libérale fondée sur efficacité économique, la décentralisation, l’acceptabilité des mesures. L’extrême droite développe une conception de l’écologie nationaliste basée sur un localisme ancestral. A gauche, on trouve une conception de l’écologie centrée sur l’idée de justice sociale, bien qu’à géométrie variable. Derrière l’unanimisme face à l’urgence climatique se cachent en réalité des différences notables dans les conceptions de la décarbonation des différents groupes parlementaires
Zooming in, Stepping Back, Integrating Perspectives: The Potential of Causal Loop Diagrams for Sustainability Transformation Research
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Histoire du droit du travail par les textes, sous la dir. de P.-H. Antonmattei, A. Chatriot, L. Pécaut-Rivolier et Y. Struillou, Paris, Economica, 2025
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Conditional expectations of quantum observables I: Bohm momentum as best predictor of momentum given position
No full textInternational audienceAbstract Given the state of a quantum system, we define the conditional expectation of an observable with respect to a second observable, or commuting family of observables, as the real-valued function of the latter which best approximates the observable, in the sense of minimizing the quantum mechanical expectation of the difference squared. This corresponds to the notion of best predictor of a random variable by another random variable in non-parametric statistical regression. A basic example is the conditional expectation of the quantum mechanical momentum with respect to position, which can be identified with the Bohm momentum. We re-examine the de Broglie-Bohm theory from this perspective. As a second example we consider the simplest quantum system, that of a spin- paticle in a magnetic field. We study the conditional expectations of the Pauli spin-operators with respect to , and determine their dynamics if the pure-state wave-function solves the relevant Schr"odinger equation. Considering as a beable we can, following Bell, introduce a generalized guidance law in the form of a Markov jump process on the spectrum of which is compatible with the time evolution of the Born probabilities of the two eigenstates of The conditional expectations of the remaining spin operators are then shown to follow a piece-wise deterministic Markov process, defined by an explicit SDE. We finally examine the relationship between the conditional expectations of this paper, and the von Neumann-algebraic conditional expectation onto the sub-algebra generated by the commuting family when the joint spectrum of the latter is discrete, and derive a general expression for the conditional expectation dynamics in that context
A discrete sine–cosine based method for heterogeneous materials with non-periodic boundary conditions
No full textInternational audienceA discrete sine–cosine based method for heterogeneous materials with non-periodic boundary condition
Évaluation des connaissances des étudiants de l’UFR d’Odontologie de Reims sur les méfaits du tabac sur le parodonte et ses méthodes de sevrage
No full textEn France, le tabagisme quotidien concerne 23,1 % des adultes et demeure la première cause de mortalité évitable. Ses impacts sur la santé en générale et particulièrement sur le parodonte ont largement été documentés. Le tabagisme est reconnu comme un facteur de risque du développement des maladies parodontales par le Consensus de Chicago de 2017. Il semble ainsi évident que le sevrage tabagique représente un enjeu principal de santé publique. Les chirurgiens-dentistes font partie intégrante de la première ligne de lutte anti-tabac. Grâce à un questionnaire diffusé auprès de toutes les promotions de l’UFR Odontologie de Reims, une description des connaissances des étudiants à propos du tabac, ses méfaits sur le parodonte et ses méthodes de sevrage a été faite. Il en ressort un potentiel d’évolution dans la formation des futurs praticiens avec une volonté d’en savoir plus. Ces observations permettent de réfléchir à une stratégie pédagogique qui permettrai aux étudiants de traiter leurs patients fumeurs avec un bagage de connaissance approprié
Plastics used in agriculture and for food: uses, properties and impacts. Summary report of the collective scientific assessment
No full textFrom Straight Lines to Curved Paths: Validity and Reliability of Linear Position Transducers to Assess Linear and Angular Motion
No full textInternational audienceFor Linear Position Transducers (LPTs) to represent an ideal tool for velocity-based training, it needs to be both valid and reliable. Multiple studies assessed the reliability of LPT yet wrongfully incorporated biological variability. Moreover, all studies investigating validity conclude a negative impact of horizontal displacement, therefore constraining LPT use to solely multi-joint movement. The objectives were to assess the validity and the reliability of (1) the Tendo Sport LPT in a linear setting presenting almost no biological variability, and (2) an equation allowing the analysis of angular movement. (1) A weight of 10 kg was dropped vertically 100 times and both time and position measurement from the LPT were compared to motion equation. (2) Angular movements were performed first with a bike wheel and then by a human shoulder. The angles estimated with the equation, from LPT output, were compared to the angle measured from 3D motion capture. In the linear settings, bias, ULOA and LLOA are, respectively, equal to -0.008 s, +0.012 s and -0.016 s if errors come solely from the time measurement and 0.011 m, 0.029 m and -0.025 m if errors come solely from the distance. It is likely that error could come from both the time and the distance measurements. In the angular settings, the bike wheel condition yields excellent reliability (ICC = 0.9999) and good validity (RMSD = 9.12°), while the shoulder condition yields high validity (RMSD = 2.49°). LPT can be used to investigate angular kinematics in certain conditions described in this article and yield valid, reliable results for angles below 120°
