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Sustainable gamma irradiation strategy for GO and rGO modification: Impact on electromagnetic interference shielding efficiency
No full textInternational audienceElectromagnetic interference (EMI) has emerged as a significant issue in contemporary electronic systems, particularly within aerospace, defense, and communication technology. Graphene-derived materials, including graphene oxide (GO) and reduced graphene oxide (rGO), present remarkable potential for lightweight, flexible, and EMI shielding solutions owing to their adjustable electrical conductivity and structural integrity. This study introduces an eco-friendly method for adjusting the EMI shielding effectiveness (EMI SE) of free-standing films made from GO and rGO by controlled gamma irradiation at low (50 kGy) and high (300 kGy) doses, conducted in two types of media: air and isopropyl alcohol (IPA). The structural alterations generated by irradiation were characterized by Raman and Infrared spectroscopies, X-ray diffraction (XRD), scanning electron microscopy (SEM), and contact angle measurements, indicating changes in defect density, surface roughness, and hydrophilicity. Results indicate that gamma irradiation can precisely adjust the oxidation/reduction equilibrium, hence boosting conductivity in rGO and improving interfacial polarization in GO. Remarkably, rGO films exposed to air demonstrated exceptional EMI SE values above 20 dB in the X-band (8–12 GHz), signifying their suitability for advanced shielding applications. This research illustrates the effectiveness of gamma irradiation as an environmentally friendly, scalable method for modifying the characteristics of graphene-based materials, facilitating their incorporation into advanced aeronautical and electronic equipment
Plastics used in agriculture and for food: uses, properties and impacts. Condensed report of the collective scientific assessment
No full textWhom do you trust? The determinants of loyalty in a market without quality signals
No full textInternational audienceIn markets devoid of explicit quality signals and characterized by resource scarcity, understanding loyalty determinants is crucial for market efficiency. This study investigates the Boulogne-sur-Mer fish market, which operates through a dual mechanism: auctions and bilateral transactions. The research explores how social dynamics, trust, and loyalty influence market outcomes and efficiency. Using a comprehensive dataset of daily transactions from 2006 to 2007, we analyze traders' behaviors and pairing strategies within these sub-markets. Our findings highlight the role of trust and loyalty in shaping market dynamics, particularly in the bilateral market, where personalized relationships and specific goods trade are prevalent. We define a specific loyalty index and verify its influence on the formation of transaction prices. We then employ a valued Exponential Random Graph Model (ERGM) to identify loyalty determinants, revealing distinct patterns between the auction and bilateral markets. The study concludes that while auctions facilitate efficient exchanges of large quantities, bilateral mechanisms foster trust-based relationships essential for securing specific goods, thus ensuring a stable coexistence of both trading mechanisms.Cette étude s’intéresse au marché aux poissons de Boulogne-sur-Mer, caractérisé par l’absence de signaux explicites de qualité et par la rareté des ressources, où la compréhension des déterminants de la loyauté apparaît essentielle à l’efficacité du marché. Le dispositif repose sur un double mécanisme de transaction : les enchères et les échanges bilatéraux. À partir d’un corpus exhaustif de transactions quotidiennes (2006–2007), nous analysons les comportements des commerçants et leurs stratégies d’appariement dans ces deux sous-marchés. Les résultats mettent en lumière l’importance de la confiance et de la loyauté dans la structuration des dynamiques de marché, en particulier dans le cadre bilatéral marqué par des relations personnalisées et le commerce de produits spécifiques. Un indice de loyauté est proposé et son impact sur la formation des prix de transaction est vérifié. L’estimation d’un modèle de graphes aléatoires exponentiels valorisés (ERGM) permet d’identifier les déterminants de cette loyauté et de souligner des logiques différenciées selon les deux mécanismes. L’étude conclut que, si les enchères garantissent l’efficacité des échanges de volumes importants, les transactions bilatérales reposent sur la confiance et la stabilité relationnelle, indispensables à l’accès à certains biens, ce qui assure la complémentarité durable des deux modes d’échange
CR de Claude Langlois, *« La femme du Seigneur ». Madeleine Delbrêl en ses œuvres*
No full textInternational audienceCompte-rendu de Claude Langlois, « La femme du Seigneur ». Madeleine Delbrêl en ses œuvres, Paris, Éditions du Cerf, 2022, 405 p., 25 €
Development and validation of a thermal desorption method based on Py-GC-HRMS using in-house reference materials to quantify a set of additives in polypropylene
No full textInternational audienceBackgroundPlastic additives, such as plasticizers, flame retardants, and UV stabilizers, significantly enhance polymer properties but pose health and environmental risks due to their potential migration into food products. Current quantification methods commonly employ solvent extraction, which carries environmental and toxicity issues, as well as contamination issues. This study addresses the critical need for direct quantification of additives within plastic, using more sustainable, solvent-free, analytical methods.ResultsA thermal desorption technique combined with pyrolysis-gas chromatography-high resolution mass spectrometry (TD-GC-HRMS) is described to accurately quantify additives in food packaging. This method demonstrated excellent linearity (R2 > 0.99) within the concentration range of 0.01% to 0.2% w/w for additives including plasticizers (ATBC, BBP, DEHA, DEHP), flame retardants (TCEP, TDCIPP), and UV stabilizers (UV-326, UV-327). Limits of quantification ranged from 0.01% to 0.022% w/w, establishing robust analytical sensitivity. Method validation through an accuracy profile confirmed high reliability, with most additives exhibiting recovery rates above 97% in the first thermal desorption. Application to polypropylene food packaging samples revealed the presence of targeted additives below quantifiable levels, alongside other hazardous substances not regulated by current standards.SignificanceThe developed TD-GC-HRMS method provides a rapid, solvent-free, and reliable alternative for quantifying plastic additives in food packaging, significantly reducing environmental impact and operator exposure to hazardous chemicals
Opportunité du retrait de l’autorité parentale, protection et intérêt de l’enfant (commentaire de l’arrêt Cass., crim., 26 mars 2025, n° 24-82.966)
No full textInternational audienceLe retrait de l’autorité parentale ne constitue pas une peine mais une mesure de protection de l’enfant, de sorte que les exigences de motivation prévues par le droit pénal ne s’appliquent pas. Lorsque la juridiction de jugement fait usage de sa faculté d’ordonner le retrait de l’autorité parentale à l’encontre du parent qu’elle condamne pour avoir commis un délit contre son enfant, elle doit motiver la nécessité de prononcer ce retrait au regard de l’intérêt de l’enfant, apprécié au jour de sa décision
Le juge aux affaires familiales doit déterminer la durée du droit de visite parental en espace de rencontre (observations sur l’arrêt Cass., 1re civ., 5 mars 2025, n° 23-14.551)
No full textInternational audienceLa Cour de cassation rappelle que le juge qui ordonne un droit de visite en espace de rencontre doit impérativement en fixer la durée, conformément à l’article 1180-5 du Code de procédure civile. Cette exigence, constamment réaffirmée par la jurisprudence, se justifie par le caractère exceptionnel et strictement encadré de cette restriction au droit fondamental de l’enfant à entretenir des relations avec ses parents
The First year of the French lysimetric network
No full textInternational audienceThe need for continuous local and long-term observations in the vadose zone has been growing for many years, as they are essential for improving our understanding of the processes occurring in the vadose zone of the soil and enhancing seasonal forecasts from numerical models.Lysimeters and Ecotrons are the main tools to directly access water and nutrient transport over long periods of time. In France, with the impulsion of the ONEWATER project, a French lysimeter network is in development since April 2024, taking benefice of the existing structure.A workshop was organised to identify all the sites in France and to collect expectations. We considered about the major scientific questions that could be supported by such a network, and identifying the measurement systems and instruments that are compatible with our ambitions, as well as considering the management and diffusion of the data.In 2024, 32 lysimeter sites have been identified in France, with a total of 650 lysimeters. These sites are very heterogeneous : i) different type and size of devices : (columns, boxes, plates, mini-lysimeters, porous cells, Ecotrons, etc.); ii) different filling methods (undisturbed or reconstituted), iii) different measurements (probes, frequency…), iv) different atmospheric condition (natural or controlled)… Despite each site is unique and has specific scientific objectives, they all measure drainage.The site managers expect this network will help sharing experience in terms of device management, data valorisation and probe development, and to enable the data collected in the sites to be more used.A main issue with this heterogeneous network is to be able to compare and interprete each site. To do so several methods will be used, from in situ temporary experiment to numerical simulations. Additional, the individual sites would benefit from some upgrade, with the use of similar low-cost probes and effort will be done to share and valorize the lysimetric data
Identification of the first plant caffeoyl-quinate esterases in Cichorium intybus
No full textInternational audienceChlorogenic acid (5-CQA) is a caffeic acid ester widely accumulated in higher plants. It plays roles in defense against biotic and abiotic stresses. As its biosynthetic pathway shares common enzymes and intermediates with that of lignin, 5-CQA has long been hypothesized to be involved in lignin formation. However, to date, no plant enzymes have been identified that efficiently convert 5-CQA into lignin precursors. While investigating enzymes involved in the conversion of 5-CQA to isochlorogenic acid (3,5-DiCQA) in chicory ( Cichorium intybus ), we identified two enzymes from the GDSL esterase/lipase family, CiCQE1 and CiCQE3. Biochemical characterization and functional analysis in tobacco revealed that both enzymes can hydrolyze 5-CQA and 3,5-DiCQA to release caffeic acid (CA) both in vitro and in planta . The genes encoding CiCQE1 and CiCQE3 are predominantly expressed in chicory roots, where 5-CQA and 3,5-DiCQA accumulate to high levels. When transiently expressed in tobacco leaves, accumulation of caffeoyl-putrescine in addition to CA was observed. This may suggest that released CA may be converted to caffeoyl-CoA to fuel other metabolic paths. The hydrolysis of caffeoyl-shikimate, a compound structurally close to 5-CQA, to caffeic acid, and its subsequent conversion to caffeoyl-CoA, has been shown to be an important step in the biosynthesis of G and S monolignols. Since CiCQE1 and CiCQE3 catalyze similar reactions using 5-CQA as substrate, these enzymes may represent a novel route for 5-CQA remobilization in chicory roots. Further functional characterization of the role of these genes using mutant lines is still required to fully understand their role in planta