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Fiche d'inventaire Patrimoine Culturel Immatériel. Pratiques de pêche passives sur le bassin Loire : le guideau et le filet-barrage
No full textLa pêche sur le bassin versant du plus long fleuve de France, la Loire, est une pratique polymorphe ancestrale. Pratiquée par différentes communautés riveraines, la pêche revêt un caractère pluriel au sein de ce territoire ligérien. Plusieurs pêcheurs professionnels subsistent encore, et exercent leur métier sur le domaine public fluvial ligérien et les rivières adjacentes, découpés en lots. Parmi ces pêcheurs, quelques-uns pratiquent des pêches particulières, employant des engins spécifiques que sont les guideaux et les filets-barrages.Ces deux types d'engins de pêche sont notamment déployés sur la Loire moyenne, entre la Loire à l'amont de Nantes et la région nivernaise, à hauteur d'un seul maximum par lot. Réglementés, ces engins ne sont utilisables que selon certaines conditions (licences, calendrier, relève, etc.).Le guideau, ou dideau, est tendu la nuit, dans le sens du courant, lors des crues automnales et hivernales, depuis un bateau fixe spécifiquement aménagé, et cible l'anguille d'avalaison.Le filet-barrage, installé au printemps, cible l'alose et les poissons migrateurs de grande taille (auparavant le saumon), le carrelet qui effectue la capture est relevé depuis une toue fixe. Les derniers pêcheurs au guideau et au filet-barrage vendent le produit de leur pêche selon des circuits courts et se trouvent à l'avant-poste des bouleversements environnementaux qui conduisent au déclin marqué des espèces migratrices ciblées par ces pratiques. Par ailleurs, ils perpétuent une activité traditionnelle ligérienne, et collectent d'importantes données, utiles pour le suivi scientifique des populations de poissons grands migrateurs et la surveillance quotidienne de l'état écologique du fleuve et ses affluents. Enfin, les prises font ou faisaient, pour nombre d'entre elles, partie intégrante du patrimoine gastronomique ligérien
A new approach for the optical detection of breast cancer cells using NIR imaging agents based on lanthanide complexes incorporated into nanoparticles
No full textInternational audienceNear-infrared (NIR) optical imaging is of strong interest for biological research and medical diagnostic. In addition to deeper tissues penetration, emission in the NIR allows to improve both the detection and image resolution. The luminescence of lanthanide cations (Ln3+) is attractive as they exhibit sharp emission bands that are not affected by any environmental changes. Ln3+ are sensitized with a chromophore that absorbs excitation light and transfers the resulting energy. Metallacrowns (MCs) form a scaffold that coordinate and efficiently sensitize the Ln3+ 1,2,3,4. In order to address the required biocompatibility and selectivity of detection, we have developed a methodology to encapsulate a large number of Ln3+-based MCs in functionalized polystyrene nanoparticles (PS-NPs) through a rapid swelling procedure5.In this project, HER2-positive breast cancer was taken as a model to develop targeted Ln3+-based NIR optical imaging agents. The first PS-NPs containing NIR-emitting MCs with specific HER2 targeting, addressed by the surface conjugation with monoclonal antibodies, were synthesized and characterized. These PS-NPs showed: (i) specific binding properties to HER2 at the surface of cancer cells, (ii) unique photophysical properties in the NIR range due to Yb3+ emission, and (iii) an absence of cytotoxicity. These PS-NPs constitute a versatile system that can be easily adapted to other targets, including multiplex and/or multimodal imaging
Molecular and supramolecular routes to enhance Gadolinium-based contrast agents relaxivity: How far are we from the theoretical optimal value?
No full textInternational audienceGadolinium Based Contrast Agents (GBCAs) are routinely used in the clinical practice to enhance the diagnostic potential of MRI. Their contrast enhancing capabilities rely on their ability to increase the relaxation rate of tissue water protons. This property is expressed by the relaxivity, whose value is determined by structural, electronic and dynamic characteristics of the GBCA. Based on extensive experimental work over the past four decades and the well-established theory of paramagnetic relaxation, it is usually possible to correlate observed relaxivity values to specific molecular properties. Key determinants include the number of water molecules and/ or exchangeable protons in the first and second coordination spheres, their distance from the paramagnetic Gd 3+ ion, the ion's electronic relaxation time, molecular reorientation time, and the exchange rate of the coordinated water molecules. Understanding the key factors that affect relaxivity has enabled the design of systems with optimized structural and dynamic properties. However, some examples demonstrate exceptional relaxivity which cannot be fully explained by the established theory. In particular, GBCAs within confined environments show significant promise for developing high-relaxivity agents. Overall, one may state that nowadays it is possible to attain highly efficient GBCAs thanks to the in-depth understanding of the structural and dynamic determinants of their relaxivity, together with the optimization of their in vivo stability and biodistribution/excretion properties. This knowledge is crucial for the rational design of the next generation of MRI CAs. The domain of Molecular Imaging will also largely benefit from these efforts
Saccharomyces cerevisiae Mub1, a substrate adaptor of E 3 ubiquitin ligase Ubr2, modulates sensitivity to cell wall stressors through multiple transcription factors
No full textInternational audienceYeasts evolved a complex regulatory programme to build and maintain their cell wall, the primary structure through which they interact with their environment. However, how this programme ties to essential cellular processes mostly remains unclear. Here, we focus on Saccharomyces cerevisiae MYND‐type zinc finger protein MUB1 (Mub1), an adaptor protein of E3 ubiquitin‐protein ligase Ubr2 that was previously associated with regulating proteasome genes through the transcription factor Rpn4. We show that S. cerevisiae cells lacking Mub1 become hyper‐tolerant to standard cell wall stressors, outperforming wild‐type cells. This protective mub1Δ phenotype stems from the activity of several transcription factors, leading to the inhibition of cell wall remodelling, a typically protective process that becomes maladaptive during chronic cell wall stress in laboratory conditions. Based on these results, we suggest that Mub1 regulates not only Rpn4 but a much broader range of transcription factors, and thus serves as an in‐so‐far unrecognised regulatory hub directly linking cell wall robustness with the ubiquitin‐proteasome system
Microwave‐Assisted Organic Syntheses in Deep Eutectic Solvents: A Win‐Win Association for Sustainable Chemistry
No full textInternational audienceThe 12 principles of green chemistry guide the scientific community toward the development of chemical processes that are more respectful of the environment and safer for human health. In organic synthesis, this mainly involves the use of sustainable alternatives to conventional organic solvents, energy‐efficient processes, and waste minimization. In this context, this review focuses on the use of deep eutectic solvents (DES) in microwave‐assisted organic synthesis. Indeed, DES, due to their nonvolatility, nonflammability, and low toxicity compared to conventional organic solvents, are considered desirable “green solvents” for the development of environmentally friendly processes. Moreover, their physicochemical properties make them ideal media for microwave heating. Thus, all organic syntheses using DES as solvent and microwave heating documented in the literature are reported, including heterocycle synthesis, nitrogen quaternization reactions, 5‐hydroxymethylfurfural production, Knoevenagel reactions, and miscellaneous transformations. The recyclability of DES‐based systems and their scalability, where applicable, are reported. Mechanistical considerations when DES are involved are also described. Compared with conventional heating methods, microwave heating of DES media generally results in good yields and a significant reduction in reaction times. This DES‐MW combination appears promising for more sustainable organic syntheses
Exoskeletons as potential devices to support and enhance rescuers’ chest compression performance during out-of-hospital cardiac arrest
No full textInternational audienceExoskeletons are wearable structures that support and assist movement, or augment the capabilities of the human body. These functionalities could theoretically assist bystanders or rescuers performing manual chest compressions during out-of-hospital cardiac arrest, as this emergency procedure is prone to physical exhaustion. Compressions are an intense muscular effort involving a dynamic muscular pattern with conflicting postural constraints. Rescuer fatigue sets in rapidly, leading to postural instability and a lack of mechanical power delivered by the arms to the patient's torso, which affects hemodynamic efficiency. Physical augmentation and postural stabilization are two functions that could be provided by an exoskeleton during cardiopulmonary resuscitation. This device would combine the advantages of manual and mechanical chest compressions, bypassing anthropometric parameters such as the rescuer's aerobic capacity and muscle mass to maintain efficient chest compressions, and avoiding the negative issues associated with over-assistance through a servomotor function. This concept paper examines the specifications of an ideal theoretical device in this context, noting the potential technical difficulties and barriers to implementation.</div
Derivation et validation des modèles à compartiments : implications en imagerie dynamique
No full textInternational audienceCompartment models are mathematical representations of the transport of a chemical substance in the human body, assuming uniform concentration within each compartment, which corresponds to a distinct body part. Widely used in pharmaceutical and medical imaging through pharmacokinetic and tracer kinetic (TK) models, they are formulated as systems of time-dependent ordinary differential equations. However, these models do not account for the spatial dependence of physiological processes within individual compartments. This work aims to explore the physical interpretation of these models through mathematical derivation and to analyze their limitations. Three TK models are derived from more complex models regarding the physiological processes represented. The derivation introduces the hypotheses relevant to these processes. The most notable is the well-mixed hypothesis, resembling concentration homogeneity in the region of interest. The hypotheses are numerically tested by simulating the more complex model and evaluating the reduced models' residuals. For a given tracer molecule, the validity of TK models is found to decrease as voxel size increases. This work proposes an algorithm to compute the maximum voxel size, above which the reduced models' residuals exceed a chosen error threshold. For a 3 % error, voxel sizes larger than 250 µm are found critical for highly permeable vessels, while sizes smaller than 4 mm induce less than 3 % error in non-permeable vessels. Tested on literature-derived datasets, these findings identify diffusion as the underlying phenomenon leading to well-mixed compartments, and highlight the need for high spatial resolution imaging to improve TK parameters ground truth estimation.Les modèles à compartiments sont des représentations mathématiques du transport d'une substance dans le corps humain qui supposent une distribution uniforme de sa concentration au sein de chaque compartiment, correspondant à une partie du corps. Étant largement utilisés dans les domaines pharmaceutiques et de l'imagerie médicale à travers les modèles de pharmacocinétique et de cinétique des traceurs (TK), ils sont formulés sous forme de systèmes d'équations différentielles ordinaires dépendantes du temps. Toutefois, ces modèles ne prennent pas en compte la dépendance spatiale des processus physiologiques au sein de chacun des compartiments. Cet article a pour objectif d'explorer l'interprétation physique de ces modèles grâce à leur dérivation mathématique et d'analyser leurs limites. Trois modèles TK ont été dérivés à partir de modèles plus complexes en termes de processus représentés. La dérivation met en exergue les hypothèses pertinentes pour la description de ces processus. La plus remarquable est l'hypothèse "well-mixed" (bien mélangé), qui se rapproche d'une homogénéité de la concentration dans la région d'intérêt. Les hypothèses ont ensuite été testées numériquement par une simulation du modèle le plus complexe, puis par l'évaluation des résidus des modèles réduits. Pour une molécule traceur donnée, nous observons une diminution de la validité des modèles TK lorsque la taille d'un voxel de l'image augmente. Le travail présenté met en place un algorithme permettant de calculer la taille maximale d'un voxel au-delà de laquelle les résidus des modèles réduits dépassent un seuil d'erreur. Pour une erreur de 3%, nous observons que des tailles de voxel supérieures à 250 µm sont considérées comme critiques à haute perméabilité vasculaire, alors que des tailles inférieures à 4 mm introduisent moins de 3 % d'erreur dans des vaisseaux sanguins non perméables. En les testant sur des données issues de la littérature, ces découvertes identifient la diffusion comme le phénomène sous-jacent à des compartiments "bien mélangés" et soulignent la nécessité de résolutions spatiales élevées en imagerie médicale afin d'améliorer le réalisme de l'estimation des paramètres TK
The acute effect of two exercise modalities on neurocognitive responses in postmenopausal women: A randomized controlled trial
No full textInternational audienceMenopause‐related cognitive decline, often worsened by vasomotor symptoms (VMS), might be mitigated by high cardiorespiratory fitness (CRF). Although acute exercise supports neurocognitive function, its effects vary by exercise and individual characteristics. In this study, we investigated the acute effects of isometric resistance exercise (IRE) and high‐intensity interval exercise (HIIE) on prefrontal cortex oxygenation and cognitive performance in postmenopausal women and examined the influence of VMS and CRF on these outcomes. A cross‐over randomized controlled trial was conducted among 29 women aged 55 ± 3 years. The HIIE session included two sets of 12 × 15 s at 100% maximal aerobic power, and the IRE session included 4 × 2 min at 30% maximal voluntary force. Cognitive functions were evaluated before and after sessions using the MEM‐III story recall test (episodic memory), Stroop task (inhibitory control) and n‐back task (working memory). Prefrontal cortex oxygenation was assessed by measuring oxyhaemoglobin (ΔHbO2), deoxygenated haemoglobin (ΔHHb) and total haemoglobin (ΔtHb) concentrations before, during and after each session. No effect of exercise was noted on cognitive performance. However, prefrontal cortex oxygenation increased during HIIE (ΔHbO2: d = 0.99, p < 0.0001; ΔHHb: d = 0.68, p = 0.018; ΔtHb: d = 0.96, p = 0.001), during IRE (ΔHbO2: d = 1.2, p = 0.003) and post‐HIIE (ΔHbO2 and ΔtHb: d > 1; p < 0.0001) versus control. CRF positively modulated cognitive and cerebrovascular responses to IRE, whereas VMS showed no influence. IRE and HIIE did not improve cognitive performance in postmenopausal women, but increased prefrontal cortex oxygenation, with sustained effects after HIIE. CRF positively modulated responses, whereas VMS did not, underscoring the importance of maintaining high CRF to support brain health in this population
Self-assembled inorganic tubular nanomembrane piezoelectrics for acoustic wave resonators
No full textShaping piezoelectrics into smart 3D microstructures is an emerging topic considering the opportunity to unlock new functions through shape or topological engineering. Solutions are already available to fabricate nanomembrane-based 3D piezoelectric composites and origamilike structures. However, all those approaches lead to the loss of electromechanical resonance properties when organic backbone layers with unfavorable mechanical quality factors are used.Concurrently, 2D free-standing piezoelectric nanomembranes applied for acoustic wave resonators require thin film materials with low intrinsic stress to avoid the high risk of device rupture caused when the lateral dimensions are increased. We demonstrate here for the first time 3D self-assembled piezoelectrics made exclusively from inorganic material. The fine control of mechanical stress and nanomembrane release is engineered on purpose to shape freestanding nanomembranes into conformably stable tubular structures. The resulting piezoelectric resonator can be tuned in diameter, length and winding number. We validate here devices with tubular and rolling length up to 11 mm and 3.5 mm respectively and prove functionality with a 1-port resonator and 2-port delay-line architecture built with up to 10 mm² of free-standing piezoelectric nanomembrane. Such devices could open new application possibilities for telecommunication, microfluidics or energy harvesting applications considering the large functional surface adding another degree of freedom for topological design.</div
Development and validation of the participatory approach questionnaire (PARTAQUE) in cancer teams: a ready-to-use tool for enhancing the quality of work life for caregivers
No full textInternational audienceThe Participative Approach (PA) has demonstrated the potential to enhance both the quality of work life and the quality of care within French cancer teams. Whilst a number of studies have demonstrated that the participatory approach exerts a positive impact on all stakeholders within the care context, none of them have thus far used a measurement of the PA that has been scientifically validated. Therefore, the aim of this research was to develop and validate the PARTAQUE (Participatory Approach Questionnaire) and to assess its psychometric properties. This objective was pursued by conducting three independent studies in French healthcare organizations. The assessment of the factorial structure of the scale confirmed a good fit with a second-order factor model, and the test of convergent and predictive validity showed consistent relationships with theorized outcomes (e.g., attitudinal and behavioral work outcomes, occupational health indicators). The implications for research and practice are then discussed