11 results on '"Lecomte V"'
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2. Oilseed and protein crops grown in French organic farms: an overview of cultivation practices for sunflower and soybean☆
- Author
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Le Gall Cécile, Lecomte Vincent, and Wagner Dominique
- Subjects
organic production ,soybean ,sunflower ,cultural practices ,survey ,Oils, fats, and waxes ,TP670-699 - Abstract
The development of organic agriculture in France was steady since 2010 but became stronger since 2014. Like other crops, the cultivated areas of organic soybean and sunflower doubled from 2014 to 2018. With a view to better characterize cultural practices in organic production, Terres Inovia and ITAB (in collaboration with Agence Bio) conducted in 2016 and 2017 a national farmers’ survey. These surveys reveal that sunflower was mainly cultivated over the same types of soil than in conventional production but were integrated in more diversified rotations. The main differences between organic and conventional systems concern sowing date and weed control. Organic sunflower was sown very lately compared to conventional one, which impacted the yield severely. Weed were controlled through ploughing, mechanical weeding and crop rotation and weed control was judged as satisfying by a major part of producers. Concerning soybean, a great difference is the use of irrigation which is almost systematic in conventional but concerned only 50% of cultivated area in organic production. Contrary to sunflower, soybean is integrated in short crop rotation, particularly when it was irrigated. This demonstrated the high profitability of soybean in organic systems. Like for sunflower, weed control done through ploughing, mechanical weeding, and crop rotation and weed control was also judged satisfying; nevertheless, criteria on harvest impurities are more severe and to respect them, organic farmers also use hand weeding in complement. These surveys will be reconducted over the years to be able to follow the changes of cultural practices over the years.
- Published
- 2022
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3. Mutual Linearity of Nonequilibrium Network Currents.
- Author
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Harunari PE, Dal Cengio S, Lecomte V, and Polettini M
- Abstract
For continuous-time Markov chains and open unimolecular chemical reaction networks, we prove that any two stationary currents are linearly related upon perturbations of a single edge's transition rates, arbitrarily far from equilibrium. We extend the result to nonstationary currents in the frequency domain, provide and discuss an explicit expression for the current-current susceptibility in terms of the network topology, and discuss possible generalizations. In practical scenarios, the mutual linearity relation has predictive power and can be used as a tool for inference or model proof testing.
- Published
- 2024
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4. Assessing the Potential Ecotoxicological Risk of Different Organic Amendments Used in Agriculture: Approach Using Acute Toxicity Tests on Plants and Earthworms.
- Author
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Roques O, Bedell JP, Le Maux J, Wiest L, Nélieu S, Mougin C, Cheviron N, Santini O, Lecomte V, and Bayard R
- Subjects
- Animals, Sewage, Agriculture, Plants, Soil chemistry, Toxicity Tests, Acute, Oligochaeta, Environmental Pollutants analysis, Soil Pollutants analysis
- Abstract
In Europe, spreading organic wastes to fertilize soils is an alternative commonly used instead of chemical fertilizers. Through their contributions of nutrients and organic matter, these wastes promote plant growth and thus agricultural production. However, these organic amendments can also contain mineral and organic pollutants requiring chemical and ecotoxicological analyses to guarantee their harmlessness on soil and its organisms during spreading. The purpose of this study was to assess the potential toxicity of three organic amendments from different sources (sewage sludge, dairy cow manure, dairy cow slurry) by performing chemical analyses and acute toxicity tests on three types of organism: earthworms, plants, soil microbial communities. Chemical analysis revealed a higher content of certain pharmaceuticals, polycyclic aromatic hydrocarbons and metals in sewage sludge in comparison with the two other types of organic wastes. The ecotoxicological assessment showed a dose-dependent effect on soil organisms for the three organic amendments with higher toxic effects during the exposure tests with a soil amended with dairy cow slurry. However, at realistic spreading doses (10 and 20 g kg
-1 dry weight of organic amendments) on a representative exposed soil, organic amendment did not show any toxicity in the three organisms studied and had positive effects such as increased earthworm biomass, increased plant root growth and earthworm behavior showing attraction for organic amendment. On the contrary, exposure assays carried out on a limited substrate like sandy soil showed increased toxicity of organic amendments on plant germination and root growth. Overall, the ecotoxicological analysis revealed greater toxicity for soil organisms during the amendment of cow slurry, contrary to the chemical analysis which showed the potential high risk of spreading sewage sludge due to the presence of a higher quantity of pollutants. The analysis of the chemical composition and use of acute toxicity tests is the first essential step for assessing the ecotoxicological risk of spreading organic amendments on soil organisms. In addition to standard tests, the study suggests using a representative soil in acute toxicity tests to avoid overestimating the toxic effects of these organic amendments., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)- Published
- 2023
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5. Superparamagnetic Iron Oxide Nanoparticles (SPION): From Fundamentals to State-of-the-Art Innovative Applications for Cancer Therapy.
- Author
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Vangijzegem T, Lecomte V, Ternad I, Van Leuven L, Muller RN, Stanicki D, and Laurent S
- Abstract
Despite significant advances in cancer therapy over the years, its complex pathological process still represents a major health challenge when seeking effective treatment and improved healthcare. With the advent of nanotechnologies, nanomedicine-based cancer therapy has been widely explored as a promising technology able to handle the requirements of the clinical sector. Superparamagnetic iron oxide nanoparticles (SPION) have been at the forefront of nanotechnology development since the mid-1990s, thanks to their former role as contrast agents for magnetic resonance imaging. Though their use as MRI probes has been discontinued due to an unfavorable cost/benefit ratio, several innovative applications as therapeutic tools have prompted a renewal of interest. The unique characteristics of SPION, i.e., their magnetic properties enabling specific response when submitted to high frequency (magnetic hyperthermia) or low frequency (magneto-mechanical therapy) alternating magnetic field, and their ability to generate reactive oxygen species (either intrinsically or when activated using various stimuli), make them particularly adapted for cancer therapy. This review provides a comprehensive description of the fundamental aspects of SPION formulation and highlights various recent approaches regarding in vivo applications in the field of cancer therapy.
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- 2023
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6. Advances in the Mechanistic Understanding of Iron Oxide Nanoparticles' Radiosensitizing Properties.
- Author
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Ternad I, Penninckx S, Lecomte V, Vangijzegem T, Conrard L, Lucas S, Heuskin AC, Michiels C, Muller RN, Stanicki D, and Laurent S
- Abstract
Among the plethora of nanosystems used in the field of theranostics, iron oxide nanoparticles (IONPs) occupy a central place because of their biocompatibility and magnetic properties. In this study, we highlight the radiosensitizing effect of two IONPs formulations (namely 7 nm carboxylated IONPs and PEG
5000 -IONPs) on A549 lung carcinoma cells when exposed to 225 kV X-rays after 6 h, 24 h and 48 h incubation. The hypothesis that nanoparticles exhibit their radiosensitizing effect by weakening cells through the inhibition of detoxification enzymes was evidenced by thioredoxin reductase activity monitoring. In particular, a good correlation between the amplification effect at 2 Gy and the residual activity of thioredoxin reductase was observed, which is consistent with previous observations made for gold nanoparticles (NPs). This emphasizes that NP-induced radiosensitization does not result solely from physical phenomena but also results from biological events.- Published
- 2023
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7. Ameliorating high-fat diet-induced sperm and testicular oxidative damage by micronutrient-based antioxidant intervention in rats.
- Author
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Billah MM, Khatiwada S, Lecomte V, Morris MJ, and Maloney CA
- Subjects
- 8-Hydroxy-2'-Deoxyguanosine, Animals, Diet, High-Fat adverse effects, Folic Acid pharmacology, Glutathione metabolism, Male, Micronutrients, NF-E2-Related Factor 2 metabolism, Obesity metabolism, Oxidative Stress, RNA, Messenger metabolism, Rats, Rats, Sprague-Dawley, Semen metabolism, Spermatozoa, Superoxide Dismutase metabolism, Antioxidants metabolism, Antioxidants pharmacology, Testis
- Abstract
Purpose: Emerging evidence from rodent studies suggests that high-fat-diet (HFD)-induced obesity is characterized by increased oxidative damage in sperm and testis. However, interventions using micronutrient supplementation to mitigate oxidative damage in obesity have not been extensively studied. This study aimed to investigate the effect of an antioxidant-based micronutrient supplement (added folate, vitamin B
6 , choline, betaine, and zinc) on sperm and testicular oxidative damage in HFD-fed male Sprague Dawley rats., Methods: Rats (3-weeks-old, 12/group) were weaned onto control (C) or HFD (H) or these diets with micronutrient supplement (CS; HS); sperm and testis were harvested at 30.5 weeks. To assess oxidative stress and antioxidant capacity in testis, levels of malondialdehyde (MDA), glutathione (GSH), folate and susceptibility index (SI) of pro-oxidative damage, mRNA expression of Nrf2, NFκB-p65, IL-6, IL-10 and TNF-α, in addition to superoxide-dismutase (SOD), catalase and glutathione-peroxidase (GPx) activities were measured. 8-hydroxy-2-deoxyguanosine (8-OHdG) were assessed in both sperm and testis., Results: HFD-fed rats had significantly increased 8-OHdG content in sperm and testis, increased testicular SI, decreased testicular weight, SOD and GPx activity compared to control. Strikingly, supplementation of HFD appeared to significantly reduce 8-OHdG in sperm and testis (22% and 24.3%, respectively), reduce testicular SI and MDA content (28% and 40%, respectively), increase testicular weight (24%), SOD and GPX activity (30% and 70%, respectively) and GSH content (19%). Moreover, supplementation had significant impact to increase testicular folate content regardless of diet. Furthermore, an overall effect of supplementation to increase testicular mRNA expression of Nrf2 was observed across groups. Interestingly, testicular SI was positively correlated with sperm and testicular 8-OHdG and MDA content, suggesting a critical role of testicular antioxidant activity to combat oxidative damage in sperm and testis., Conclusion: Our findings suggest that antioxidant-based micronutrient supplement has the potential to interrupt HFD-induced sperm and testicular oxidative damage by improving testicular antioxidant capacity., (© 2022. The Author(s).)- Published
- 2022
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8. Biotinylation of a MRI/Gd BNCT theranostic agent to access a novel tumour-targeted delivery system.
- Author
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Lanfranco A, Alberti D, Parisotto S, Renzi P, Lecomte V, Geninatti Crich S, and Deagostino A
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- Biotin, Biotinylation, HeLa Cells, Humans, Magnetic Resonance Imaging methods, Boron Neutron Capture Therapy methods, Precision Medicine
- Abstract
A new biotin based BNCT (Boron Neutron Capture Therapy)-MRI theranostic is here reported (Gd-AL01) in order to exploit the high tumour specificity of biotin and the selectivity of BNCT in a synergistic manner. The key is the preparation of an intermediate where an o -carborane is linked to two amino groups orthogonally protected via the exploitation of two consecutive Mitsunobu reactions. The aim is its functionalisation in two different steps with biotin as the biological vector and Gd-DOTA as the MRI probe and GdNCT agent. Cell uptake was evaluated on HeLa tumour cells overexpressing biotin receptors. The internalised boron is proportional to the concentration of the theranostic agent incubated in the presence of cells. A maximum value of 77 ppm is reached and a well detectable signal intensity increase in the T
1 weighted image of HeLa cells was observed, differently from clinically used GdHPDO3A, where no contrast is detected. These excellent results indicate that Gd-AL01 can be applied as a theranostic probe in BNCT studies.- Published
- 2022
- Full Text
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9. Microscopic interplay of temperature and disorder of a one-dimensional elastic interface.
- Author
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Caballero N, Giamarchi T, Lecomte V, and Agoritsas E
- Abstract
Elastic interfaces display scale-invariant geometrical fluctuations at sufficiently large lengthscales. Their asymptotic static roughness then follows a power-law behavior, whose associated exponent provides a robust signature of the universality class to which they belong. The associated prefactor has instead a nonuniversal amplitude fixed by the microscopic interplay between thermal fluctuations and disorder, usually hidden below experimental resolution. Here we compute numerically the roughness of a one-dimensional elastic interface subject to both thermal fluctuations and a quenched disorder with a finite correlation length. We evidence the existence of a power-law regime at short lengthscales. We determine the corresponding exponent ζ_{dis} and find compelling numerical evidence that, contrarily to available analytic predictions, one has ζ_{dis}<1. We discuss the consequences on the temperature dependence of the roughness and the connection with the asymptotic random-manifold regime at large lengthscales. We also discuss the implications of our findings for other systems such as the Kardar-Parisi-Zhang equation and the Burgers turbulence.
- Published
- 2022
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10. SIPIBEL observatory: Data on usual pollutants (solids, organic matter, nutrients, ions) and micropollutants (pharmaceuticals, surfactants, metals), biological and ecotoxicity indicators in hospital and urban wastewater, in treated effluent and sludge from wastewater treatment plant, and in surface and groundwater.
- Author
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Bertrand-Krajewski JL, Bournique R, Lecomte V, Pernin N, Wiest L, Bazin C, Bouchez A, Brelot E, Cournoyer B, Chonova T, Dagot C, Di Majo P, Gonzalez-Ospina A, Klein A, Labanowski J, Lévi Y, Perrodin Y, Rabello-Vargas S, Reuilly L, Roch A, and Wahl A
- Abstract
The Bellecombe pilot site - SIPIBEL - was created in 2010 in order to study the characterisation, treatability and impacts of hospital effluents in an urban wastewater treatment plant. This pilot site is composed of: i) the Alpes Léman hospital (CHAL), opened in February 2012, ii) the Bellecombe wastewater treatment plant, with two separate treatment lines allowing to fully separate the hospital wastewater and the urban wastewater, and iii) the Arve River as the receiving water body and a tributary of the Rhône River and the Geneva aquifer. The database includes in total 48 439 values measured on 961 samples (raw and treated hospital and urban wastewater, activated sludge in aeration tanks, dried sludge after dewatering, river and groundwater, and a few additional campaigns in aerobic and anaerobic sewers) with 44 455 physico-chemistry values (including 15 pharmaceuticals and 14 related transformation products, biocides compounds, metals, organic micropollutants), 2 193 bioassay values (ecotoxicity), 1 679 microbiology values (including microorganisms and antibioresistance indicators) and 112 hydrobiology values., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships which have or could be perceived to have influenced the work reported in this article., (© 2021 The Author(s). Published by Elsevier Inc.)
- Published
- 2021
- Full Text
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11. Supersymmetries in nonequilibrium Langevin dynamics.
- Author
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Marguet B, Agoritsas E, Canet L, and Lecomte V
- Abstract
Stochastic phenomena are often described by Langevin equations, which serve as a mesoscopic model for microscopic dynamics. It has been known since the work of Parisi and Sourlas that reversible (or equilibrium) dynamics present supersymmetries (SUSYs). These are revealed when the path-integral action is written as a function not only of the physical fields, but also of Grassmann fields representing a Jacobian arising from the noise distribution. SUSYs leave the action invariant upon a transformation of the fields that mixes the physical and the Grassmann ones. We show that contrary to common belief, it is possible to extend the known reversible construction to the case of arbitrary irreversible dynamics, for overdamped Langevin equations with additive white noise-provided their steady state is known. The construction is based on the fact that the Grassmann representation of the functional determinant is not unique, and can be chosen so as to present a generalization of the Parisi-Sourlas SUSY. We show how such SUSYs are related to time-reversal symmetries and allow one to derive modified fluctuation-dissipation relations valid in nonequilibrium. We give as a concrete example the results for the Kardar-Parisi-Zhang equation.
- Published
- 2021
- Full Text
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