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International audience; The molecular simulation of interfacial systems is a matter of debate because of the choice of many input parameters that can affect significantly the performance of the force field of reproducing the surface tension and the coexisting densities. After developing a robust methodology for the calculation of the surface tension on a Lennard-Jones fluid, we apply it with different force fields to calculate the density and surface tension of pure constituents of epoxy resins. By using the model that best reproduces the experimental density and surface tension, we investigate the impact of composition in mass fraction on uncured epoxy resins and the effects of degree of cross-linking on cured resins.

Chemical models that describe the atmospheric multiphase (gas/aqueous) system often include detailed kinetic and mechanistic schemes describing chemical reactions in both phases. The present study explores the importance of properties including the chemical composition of droplet populations, such as pH value and iron present in only a few droplets, as well as droplet size and their distribution. It is found that the assumption of evenly distributed iron in all cloud droplets leads to an underestimate by up to 1 order of magnitude of OH concentrations in the aqueous phase, whereas the predicted iron(II)/iron(total) ratio is overestimated by up to a factor of 2. While the sulfate mass formed in cloud droplets is not largely affected by any of the assumptions, the predicted secondary organic aerosol mass varies by an order of magnitude. This sensitivity study reveals that multiphase chemistry model studies should focus not only on chemical mechanism development but also on careful considerations of droplet properties to comprehensively describe the atmospheric multiphase chemical system.

International audience; Metallic bismuth and Bi-oxyfluoride nanoparticles (NPs) are successfully synthesized by non-reactive and reactive sputtering of a Bi target onto 1-butyl-3-methylimidazolium bis(trifluoro-methylsulfonyl)imide ([BMIM][TFSI]) ionic liquid (IL). Non-reactive sputtering is realized in pure Ar plasma, where isotropic, well crystallized and dispersed Bi NPs of 3-7 nm are obtained. The diameter and the size distribution of these NPs do not significantly vary with the power, gas pressure, and sputtering time; but these sputtering parameters seem to influence the NPs concentration. Then, the introduction of O2 and CF4 gases in addition to Ar enables the reaction of radicals from plasma with Bi clusters at the liquid top surface to form Bi-oxyfluoride NPs of 3-12 nm in diameter with a photocatalytic activity. Hence, the reactive sputtering onto an IL is an efficient, original and promising method for synthesizing Bi-based compound NPs. Finally, we propose a mechanism based on reactions of species from plasma at the IL surface to explain the formation of Bi-compounds by reactive sputtering.

International audience; Highly efficient procedures were developed for greener synthesis of sequence-defined peptoid oligomers. The optimised chain elongation procedure is carried out in water-based media in a unique N to C direction, and comprises a convenient one-pot two-step deprotection/coupling sequence for the installation of each new peptoid residue. The process is so efficient that the only work-up procedure required after each intermediate coupling step is aqueous extraction. In stark contrast to the traditional procedures, the only solvents apart from water used during the synthesis and workup processes are EtOH, MeOH or EtOAc. Furthermore, there is no requirement for specialised water-soluble protecting groups or inclusion of additives apart from the reagents in the reaction media.

We present an interdisciplinary investigation of the links between the macro and microphysical properties of rain, the biochemical composition of rain, meteorological parameters, and their impacts on the phytoplankton dynamics of a mountain lake. In order to document this interdisciplinary scientific question, Lake Aydat in the French Massif Central mountains was fitted with a set of high-resolution atmospheric radars, a disdrometer, and a precipitation collector in 2020. In parallel, the lake was monitored via sensors and water sampling. To illustrate the potential of this novel experimental setup, we present a case study of a rain event that occurred in September 2020 and during which, three contrasting sub-periods were identified based on the type of rain (convective or stratiform). Using our high-temporal resolution monitoring, we show that the origin of the air mass mainly influences the chemical composition of the rain, which depends on the rain type. In contrast, the photosynthetic cell concentration in the rain is mainly influenced by meteorological variables, predominantly below-cloud scavenging. The very low concentrations of photosynthetic cells found in rain events cannot directly impact the lake's phytoplankton abundance. In contrast, the rain rate directly impacted the lake's thermal stratification during the convective event. The response of the phytoplankton depends on the genus and, interestingly, three cyanobacteria, Microcystis, Coelomoron, and Merismopedia, showed a systematic response to rain events with a sudden decrease in abundance at the lake surface immediately after rain events. In contrast, the abundance of green algae (Elakatothrix), picocyanobacteria (Synechocystis and Synechococcus), and diatoms (Asterionella and Melosira) gradually increased following the rain events, but with a lower intensity compared to the cyanobacteria species. These different phytoplankton responses to the same rainfall event could play a key role in phytoplankton dynamics in the temperate zone. Our results highlight the importance of high-frequency and time resolution monitoring of both atmosphere and lake to better understand the adaptive strategies of cyanobacteria following rain events.

International audience; In order to improve the quality of ripe mangoes by managing cultural practices and storage conditions a modeling approach was used. An existing metabolic model was updated to take specificities of mango fruit sugar metabolism, fruit respiration and transpiration into account and coupled with existing models of fruit growth in dry and fresh matter, predicted based on carbon- and water-related eco-physiological and biophysical processes, respectively (Léchaudel et al., 2015, 2017). The virtual fruit model was used to investigate the effect of cultural practices and storage conditions on several fruit characteristics that can be of interest for mango processing or fruit consumption. They included fruit fresh mass and composition of the pulp in terms of dry matter content, soluble sugars, and starch concentrations. Then, the virtual mango model was used to generate numerous simulations by combining different levels of preharvest (fruit load, irrigation, position of the fruit in the tree, harvest date) and postharvest (temperature and hygrometry) factors. Among this large number of combinations, the scenarios that produce mangoes with advantageous quality criteria, such as fruit fresh mass, dry matter content and sweetness of pulp, or number of pulp slices for drying, were selected and discussed. These scenarios could then be tested and discussed with mango industry stakeholders to assess their acceptability in a process of improving fruit quality through pre- and postharvest practices.

International audience; Organic–inorganic hybrid materials were prepared by intercalation of iron 5,10,15,20 tetrakis(4-sulfonatophenyl)porphyrin complex into layered double hydroxides (ZnCr-FeTSPP LDH) and layered simple hydroxides (Zn-FeTSPP LSH) by coprecipitation. They have been characterized by ancillary techniques to compare their structural characteristics, their morphology and their ability to form films on conductive substrates in view of preparing modified electrodes for CO2 electroreduction reaction (CO2ERR). The electrochemical behavior of intercalated FeTSPP was studied by cyclic voltammetry (CV) showing the role of the nature and pH of aqueous electrolyte solutions on the FeIII/II signal. Evaluation of the CO2ERR of ZnCr-FeTSPP modified electrode was investigated by CV and preparative scale CO2 electrolysis in 0.1 M Na2SO4 aqueous solution. Whereas FeTSPP in the same electrolyte solution exhibits 18% of CO2 conversion to CO, once intercalated into ZnCr-LDH, there is no CO formation, only H2 (FY = 75%). Using the ZnCr-NO3 modified electrode, without porphyrin, the same FY of H2 was obtained. The study illustrates the problematic and the complexity of an attractive approach for the development of innovative hybrid catalysts for heterogeneous CO2ERR.

The statistical trajectory matching (STM) method was applied successfully to derive coarse grain (CG) models for bulk properties of homopolymers. The extension of the methodology for building CG models for statistical copolymer systems is much more challenging. We present here the strategy for developing CG models for styrene–butadiene–rubber, and we compare the quality of the resulting CG force fields on the structure and thermodynamics at different chemical compositions. The CG models are used through the use of a genuine mesoscopic method called the dissipative particle dynamics method and compared to high-resolution molecular dynamics simulations. We conclude that the STM method is able to produce coarse-grained potentials that are transferable in composition by using only a few reference systems. Additionally, this methodology can be applied on any copolymer system.

Glioblastoma (GBM) is characterized by exceptionally high intratumoral heterogeneity. However, the molecular mechanisms underlying the origin of different GBM cell populations remain unclear. Here, we found that the compositions of ribosomes of GBM cells in the tumour core and edge differ due to alternative RNA splicing. The acidic pH in the core switches before messenger RNA splicing of the ribosomal gene RPL22L1 towards the RPL22L1b isoform. This allows cells to survive acidosis, increases stemness and correlates with worse patient outcome. Mechanistically, RPL22L1b promotes RNA splicing by interacting with lncMALAT1 in the nucleus and inducing its degradation. Contrarily, in the tumour edge region, RPL22L1a interacts with ribosomes in the cytoplasm and upregulates the translation of multiple messenger RNAs including TP53. We found that the RPL22L1 isoform switch is regulated by SRSF4 and identified a compound that inhibits this process and decreases tumour growth. These findings demonstrate how distinct GBM cell populations arise during tumour growth. Targeting this mechanism may decrease GBM heterogeneity and facilitate therapy.

International audience; Introduction Absolute quantification of individual metabolites in complex biological samples is crucial in targeted metabolomic profiling. Objectives An inter-laboratory test was performed to evaluate the impact of the NMR software, peak-area determination method (integration vs. deconvolution) and operator on quantification trueness and precision. Methods A synthetic urine containing 32 compounds was prepared. One site prepared the urine and calibration samples, and performed NMR acquisition. NMR spectra were acquired with two pulse sequences including water suppression used in routine analyses. The pre-processed spectra were sent to the other sites where each operator quantified the metabolites using internal referencing or external calibration, and his/her favourite in-house, open-access or commercial NMR tool. Results For 1D NMR measurements with solvent presaturation during the recovery delay (zgpr), 20 metabolites were successfully quantified by all processing strategies. Some metabolites could not be quantified by some methods. For internal referencing with TSP, only one half of the metabolites were quantified with a trueness below 5%. With peak integration and external calibration, about 90% of the metabolites were quantified with a trueness below 5%. The NMRProcFlow integration module allowed the quantification of several additional metabolites. The number of quantified metabolites and quantification trueness improved for some metabolites with deconvolution tools. Trueness and precision were not significantly different between zgpr- and NOESYpr-based spectra for about 70% of the variables. Conclusion External calibration performed better than TSP internal referencing. Inter-laboratory tests are useful when choosing to better rationalize the choice of quantification tools for NMR-based metabolomic profiling and confirm the value of spectra deconvolution tools.

International audience; A Layered Double Hydroxide (LDH) compound LDH ([Mg 2 Al(OH) 6 ] + x 2 H 2 O) intercalated with a redox active organic anion, Anthraquinone-2-sulfonate (AQS), has been envisioned as an electrode material for high power aqueous based battery. The purpose is to use this interlayer redox active molecule for the enhancement of the specific capacity at the LDH composite electrode, which should allow fast charge transfer at the negative electrode for high power storage applications. This is achieved by the reduction of AQS in charge and oxidation in discharge within a redox inactive LDH matrix. The first charge of this new material [Mg 2 Al(OH) 6 ] + [AQSO 3 ] − x 2 H 2 O leads to a capacity of 100 mAh g −1 at − 0.78 V vs Ag/AgCl (based on the weight of the active material) when operated in aqueous 1 M sodium acetate electrolyte. However, low cycling stability was observed, since a drastic loss in specific capacity occurs after the first charge. This study focuses at elucidating the mechanism behind this phenomenon via in situ UV/vis experiments. Subsequently, the dissolution of charged AQS anions into the electrolyte during the first charge of the anode has been identified and quantified. Such understanding of fading mechanism might lead to the design of improved LDH-based electrodes, which utilize redox active anions working in the positive potential range with enhanced cycling ability.

International audience; We previously reported dipeptidomimetic compounds as inhibitors of neuronal and/or inducible NO synthases (n/iNOS) with significant selectivity against endothelial NOS (eNOS). They were composed of an S-ethylisothiocitrullin-like moiety linked to an extension through a peptide bond or a 1,2,4-oxadiazole link. Here, we developed two further series where the extension size was increased to establish more favorable interactions in the NOS substrate access channel. The extension was introduced on the solid phase by the reductive alkylation of an amino-piperidine moiety or an aminoethyl segment in the case of dipeptide-like and 1,2,4-oxadiazole compounds, respectively, with various benzaldehydes. Compared to the previous series, more potent inhibitors were identified with IC 50 in the micromolar to the submicromolar range, with significant selectivity toward nNOS. As expected, most compounds did not inhibit eNOS, and molecular modeling was carried out to characterize the reasons for the selectivity toward nNOS over eNOS. Spectral studies showed that compounds were interacting at the heme active site. Finally, selected inhibitors were found to inhibit intra-cellular iNOS and nNOS expressed in RAW264.7 and INS-1 cells, respectively.

International audience; Plastic pollution represents a threat for biological communities and the ecological functions they provide in river ecosystems. In this study, we compared the microbial colonization of two plastics (biodegradable and non-biodegradable) and three natural substrata (leaves, sediment and rocks) in two study sites of an urbanized watershed differing in their plastic-contamination degree (upstream and downstream). The density and diversity of bacterial, fungal and algal communities, as well as the extracellular enzymatic activities β-glucosidase (GLU), N-acetyl-glucosaminidase (NAG) and phosphatase (PHO), were analyzed in each substrata and site over a four-week colonization experiment. Results showed higher microbial densities and enzymatic activities in leaves and sediment compared to plastics and rocks, probably due to the greater availability of organic carbon and nutrients in the former substrata. However, the microbial colonization of the two plastics was only different in the downstream site where bacterial density and enzymatic activities were higher in the biodegradable compared to the non-biodegradable plastic. Accordingly, the presence of biodegradable plastics would enhance the heterotrophic metabolism in plastic-polluted rivers.

In this study, we employed nano zero-valent iron catalysts supported on graphitized carbon (GC-nZVI) catalyst to efficiently degrade BPA under circumneutral pH conditions in both dark and UVA radiation. The GC-nZVI catalyst was characterized using specific techniques (XPS, FTIR, BET, etc.), and was used to activate both PS and PMS in solution. Although no significant BPA degradation constant (k BPA) was determined using PS/PMS or GC-nZVI alone, a significant synergistic effect was observed in the system. Under dark conditions, k BPA increased from 0.01 min-1 to 0.17 when PS was used, both in the dark and under UVA. Notably, when PMS was present in the system, the improvement was even higher with k BPA reaching 0.18 and 0.26 min-1 under dark and UVA conditions, respectively. To further support the synergistic effect, it was found that 80 % of mineralization was achieved within 2 hours of UVA exposure. Chemical quenching experiments were conducted using selective probes and kinetic modelling showed that the activation of PS/PMS produced sulfate radicals (SO 4 •−), hydroxyl radicals (• OH) and ferryl ions (Fe IV O 2+) in both systems. Additionally, GC-nZVI/PMS system demonstrated good stability in recycling experiments, with up to 70 % of BPA still being degraded after 3 cycled in 1 hour under UVA. In conclusion, the degradation efficiencies of GC-nZVI/PMS and GC-nZVI/PS systems under dark and UVA radiation were assessed for three different EDCs (BPA, E2, and EE2) in both tap and sewage treatment plant waters. This study has demonstrated that the highly efficient GC-nZVI /PS/UVA or GC-nZVI/PMS/UVA system has significant potential for application in different water matrix, and our findings provide insights into the design of heterogeneous Fenton-like and photo-Fenton-like catalysts.

International audience; Cucurbiturils are well known for their ability to form supramolecular systems with ultrahigh affinities binding. Inclusion complex between 4-aminoazobenzene and cucurbit[7]uril has been investigated in aqueous solution by ultraviolet (UV)-spectroscopy, 1 H NMR, and molecular simulations. 4-aminoazobenzene shows high affinity in acidic solutions while no association was detected in neutral solutions. The thermodynamic properties of complex formation are investigated using both UV spectroscopy and nuclear magnetic resonance (NMR) measurements. Our results highlight that the high binding constant between CB7 and 4AA (log K = 4.9) is the result of a large negative change in Δ r H°(−19 kJ/mol) and a small positive change in TΔ r S°(9 kJ/mol). The analysis of the experimental data lead to hypothesis on the structure of the complex. We have used molecular dynamics simulation to interpret experiments. Interestingly, the cis−trans isomerization of aminoazobenzene is considered. All the results are discussed and compared with those previously obtained with other host molecules.

Anethum graveolens commonly known as dill plant is a very important shrub which is widely acknowledged in traditional and modern medicine for its capacity to treat colic pain and flatulence. The purpose of this work is the study of the chemical composition and the evaluation of antibacterial, antifungal and antioxidant activities of A. graveolens essential oil. The samples were collected from the chellal region in Algeria and submitted to hydrodistillation. The essential oil extracted was analyzed by GC and GC/MS. The antibacterial and antifungal activities were tested by the disc diffusion method; seven bacteria and four phytopathogenic fungi were used. The evaluation of the antioxidant activity was carried out by the 2,2-diphenyl-1-picrylhydrazyl scavenging method. The results of the GC and GC/MS analysis allowed the identification of 22 components with carvone(34.33%), α-phellendrene (22.03%), dill ether (18.84%), limonene (6.93%) and dill apiol (5.01%) as major components. The results of the disc difusion method show that Anethum graveolens essential oil exhibits strong antibacterial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and moderate antifungal activity against Fusarium graminum and Alternaria alternata. The pure essential oil showed a moderate antioxidant activity with inhibition percentages of 49.93 ± 4.58%. This study highlights the importance of chemical constituents of A. graveolens essential oil which possesses important pharmacological effects on different pathogenic strains and could be used as substitute for synthetic antimicrobial drugs in pharmaceutical industries.

International audience; The objective of this research was to investigate the chemical composition of the essential oil of Hammada articulata obtained by steam distillation and to investigate its antioxidant and anticorrosive activities. Gas chromatography–mass spectrometry analysis of this oil resulted in the identification of 46 compounds, which accounted for 97.0% of the total oil. The major components found in this oil were hexahydrofarnesyl acetone (11.9%), β-bisabolene (10.7%), eugenol (7.7%) and 2-methyldecalin (5.3%). The DPPH radical scavenging technique was used to assess antioxidant activity. The sample of essential oil presented good antioxidant activity. This oil was tested as a corrosion inhibitor of stainless steel in 0.5 M HCl using weight loss measurements and electrochemical polarization methods. The corrosion rate of stainless steel was decreased in the presence of essential oil. The inhibition efficiency was found to increase with oil concentration to attain 96.68% at 1000 ppm. The adsorption of inhibitor on the stainless steel surface was found to be a spontaneous process and obeys Langmuir's adsorption isotherm.

International audience; In this study four BBSs are investigated namely cyrene, propylene carbonate, anisole and -valerolactone. One of the fundamental requirements for absorption refrigeration process is the high refrigerant absorption capacity. Thus, new experimental vapor-liquid-equilibria data for {CO2+BBS} systems are determined, using a calorimetric and a spectroscopic technique, at temperatures from 263.15 K to 373.15 K and pressures from 0.5 to 15 MPa. All available experimental data for these systems are used to develop an appropriate thermodynamic model capable of reproducing phase equilibria. Finally, this thermodynamic model is used to compare CO2 solubility in the four BBSs at the operating conditions of vapor absorptionrefrigeration cycle.

International audience; Aim: To develop clinical practice recommendations for nurse-administered intramuscular injections in mental health.Background: Intramuscular injection is the main route of long-acting injectable antipsychotics’ administration that appear to improve the long-term prognosis of mental illness. Specific guidelines related to the nurse administration of intramuscular injections need to be updated and to explore not only the technical aspects of this procedure.Design: A modified RAND/University of California Los Angeles (UCLA) appropriateness method Delphi study was conducted between October 2019 and September 2020.Methods: A multidisciplinary steering committee conducted a literature review and developed a list of 96 recommendations. These recommendations were submitted in a two-round Delphi electronic survey to a panel of 49 experienced practicing nurses from five mental health hospitals in France. Each recommendation was rated for its appropriateness and applicability in clinical practice on a 9-point Likert scale. Consensus among nurses was evaluated. The steering committee discussed the results after each round and approved the final set of recommendations. Results: A final set of 79 specific recommendations were accepted for their appropriateness and applicability in clinical practice. Recommendations were classified in five domains: legal and quality assurance aspects, nurse-patient relationship, hygiene, pharmacology, and injection technique. Conclusion: The established recommendations placed patients at the heart of the decisions concerning the intramuscular injection and underlined the need for specific training programs. Future research should focus on the integration of these recommendations in clinical practice, by both before-and-after studies and regular assessments of professional practices with relevant indicators. Impact: The recommendations developed for good nursing practices explored not only the technical aspects but integrated the nurse-patient relationship. These recommendations may impact usual practices of administration of long-acting injectable antipsychotics and most of them could be applied in many countries. No Patient or Public Contribution: Due to the study design.

International audience; The atmosphere is an integral component of the Earth’s microbiome. Abundance, viability, and diversity of microorganisms circulating in the air are determined by various factors including environmental physical variables and intrinsic and biological properties of microbes, all ranging over large scales. The aeromicrobiome is thus poorly understood and difficult to predict due to the high heterogeneity of the airborne microorganisms and their properties, spatially and temporally. The atmosphere acts as a highly selective dispersion means on large scales for microbial cells, exposing them to a multitude of physical and chemical atmospheric processes. We provide here a brief critical review of the current knowledge and propose future research directions aiming at improving our comprehension of the atmosphere as a biome.

Bioaerosols include bacteria that comprise about 5. Generally, the highest importance of biodegradation is identified for large droplets and at pH ~5, which may be considered representative for remote locations. The results are highly sensitive to the pH value, as it not only increases the partitioning of the acids to the aqueous phase (effective Henry’s law constant) but also the rate constants of the OH reactions which compete with the biodegradation as acid sinks.We conclude that current atmospheric chemistry models may be incomplete to assess the loss of organics in the atmospheric multiphase system as biodegradation might be a significant loss of formic and acetic acids and possibly of related organics.

The connectivity of environmental compartments through chemical and biological exchanges is often difficult to study. However, understanding the functioning of fluxes is essential in the context of climate change and the assessment of anthropogenic impacts. These exchanges can be realized through water cycle fluxes establishing interactions between the atmosphere, surface water and land.To examine the interactions between the atmosphere, surface water and land via water fluxes, we conducted a large scale field study at the watershed level, involving multiple disciplines from chemistry to meteorology and microbiology. The chemical and biological contents of water from the atmosphere (cloud and rain), to mid-mountain hydrological continuum (streams, wetlands and lake) and soil (agricultural plots) were assessed in the natural and agricultural area from Puy De Dôme (Central France) along an altitudinal gradient from puy de Dôme Mountain summit (1465 m asl) to the plain (~ 600 m asl). We set up experimental procedures for sampling, handling and analysing each environmental matrix, and the environmental context was characterized through meteorological and hydrological measurements and models. The biological and chemical variables included: isotopes of water (1H/2H and 16O/18O; laser spectroscopy), major ions (Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO3-, SO4-, IC), amino acids (LC-MS), bacterial diversity (16S metabarcoding and high-throughput sequencing) and microbial enzymatic activity associated with the nitrogen, carbon and phosphorus cycles (fluorimetric activity assays for whole Beta-Glucosidase, Leucine Aminopeptidase and Phosphatase activities).The multi-compartment analysis revealed significant differences between the compartments by the chemical variables, highlighting the compartment specificity. We estimated a chemical flux of major ions and amino acids from the atmosphere to the surface (soil and surface water). Bacterial diversity analysis showed a core community in these compartments, confirming their connectivity. Thereafter, we tried to explain bacterial diversity by the chemical variables from the studied compartments. Our analysis on microbial enzymatic activity showed an enzymatic activity associated with the nitrogen, carbon and phosphorus cycles in clouds and rain.Here, our study contributes to the understanding of atmosphere-surface interaction through field observations and atmospheric models and we attempted to better understand environmental fluxes. Our field study emphasized the importance of considering the interaction of environmental compartments in future investigations for future and gobal assessments of anthropogenic impacts, such as agrosystem effects to natural ecosystems. Key words:Field observations, Environmental interaction, Chemical flux, Microbial diversity, Atmosphere, Surface water, Soil.

International audience; Gases can partition between soil and the atmosphere, depending on their physicochemical properties. They can be degraded in both compartments by chemical or microbial processes. Polycyclic aromatic hydrocarbons (PAHs) are among such gases that are ubiquitous in the atmosphere and soils. They result mainly from the incomplete combustion or pyrolysis of organic matter; they are of concern due to their toxic, mutagenic and carcinogenic properties. PAHs are semivolatile, highly lipophilic and persistent organic pollutants. The biodegradation of PAHs and other semivolatile compounds in soil has been extensively studied. Their chemical processing in the atmosphere has also been addressed by means of many model studies. However, even though the existence of bacteria in the atmosphere is well known, the role of atmospheric biodegradation has not been extensively studied. We present a new model that includes explicit chemical processes in the atmospheric gas and aqueous phases, as well as by biodegradation in fog droplets, coupled to a soil module by volatilization and deposition processes. PAHs in soil are transported between three aerobic layers where they can be degraded by chemical and bacterial processes. Even though PAH lifetimes in soil and the atmosphere might be similar, our initial model results suggest that degradation in soil represents the major sink for PAHs. While biodegradation in soil is predicted to be the main loss process of PAHs, oxidation processes in the atmospheric gas phase also contribute significantly to overall PAH loss. Our model represents a new tool to assess the relative and absolute sink strengths of pollutants and other compounds in soil and the atmosphere. We will give an outlook on planned model studies for other compounds and discuss reasons for their choice.

In rubber technology, the subject of adhesion between two layers of synthetic non-reactive and non-crosslinked elastomers represents a challenge. Its main difficulty lies in the multiscale aspect of the mechanisms, which occur at the interfaces between polymer melts. The development of methodologies and the computational processes of multiscale simulation are carried out in this work, in order to provide some explanations about this subject. The aim of this project is to perform numerical studies of adhesion mechanisms, which materialize at the interfaces between random copolymer layers of the styrene-butadiene (SBR) type. In a first step, we extended the bayesian method (Statistical Trajectory Matching) to develop mesoscopic interaction potentials for such random copolymer melts. A second step consisted to exploit one of the coarse-grained potentials to reproduce at the mesoscale the autohesion mechanisms, across the interface of the SBR copolymers. In a third step, the STM method was extended again to perform an exploratory study on the anisotropy and grain orientation of 1,4-cis-polybutadiene system, at high degrees of coarse-graining. Ultimately, the STM method has demonstrated its capacity to predict the static properties of copolymer systems and to reproduce interface autohesion processes.; Dans l'industrie du pneumatique, la thématique de l'adhésion entre deux couches d'élastomères synthétiques non-réactifs et non-réticulés représente un challenge. Sa difficulté principale réside dans l'aspect multiéchelle des mécanismes intervenant aux interfaces entre fondus de polymère. Cette thèse s'inscrit dans la nécessité de développer des méthodologies et d'élaborer les procédés numériques de simulation multiéchelle, pour apporter des explications sur cette thématique. L'objectif de ce projet est d'étudier numériquement les mécanismes d'adhésion, qui se matérialisent aux interfaces entre couches de copolymères statistiques de type styrène-butadiène (SBR). Dans une première étape, nous avons étendu la méthode bayésienne (Statistical Trajectory Matching) pour développer des potentiels d'interactions mésoscopiques destinés aux fondus de SBR statistiques. Une deuxième étape a permis d'exploiter un des potentiels gros-grain (CG) pour reproduire à l'échelle mésoscopique les mécanismes d'autohésion, à travers l'interface des copolymères SBR. Dans une troisième étape, la méthode STM a été étendue à nouveau pour effectuer une étude exploratoire sur l'anisotropie et l'orientation des grains du 1,4-cis-polybutadiène, à de hauts degrés de nivellement. En définitive, la méthode STM a démontré sa capacité dans la prédiction des propriétés statiques des systèmes de copolymère et dans la reproduction des processus d'autohésion des interfaces.

International audience; Numerous studies report different types of responses following exposure of plants to high frequency electromagnetic fields (HF-EMF). While this phenomenon is related to tissue heating in animals, the situation is much less straightforward in plants where metabolic changes seem to occur without tissue temperature increase. We have set up an exposure system allowing reliable measurements of tissue heating (using a reflectometric probe and thermal imaging) after a long exposure (30 min) to an electromagnetic field of 2.45 GHz transmitted through a horn antenna (about 100 V m−1 at the plant level). We did not observe any heating of the tissues, but we detected rapid increases (60 min) in the accumulation of transcripts of stress-related genes (TCH1 and ZAT12 transcription factor) or involved in ROS metabolism (RBOHF and APX1). At the same time, the amounts of hydrogen peroxide and dehydroascorbic acid increased while glutathione (reduced and oxidized forms), ascorbic acid, and lipid peroxidation remained stable. Therefore, our results unambiguously show that molecular and biochemical responses occur rapidly (within 60min) in plants after exposure to an electromagnetic field, in absence of tissue heating.

International audience; The atmosphere transports biological material including living microorganisms. Whereas their survival is impaired during atmospheric transport due to desiccation and UV notably, certain organisms maintain metabolic activity and interact with physicochemical processes. This has especially been studied in clouds for its potential impacts on chemical processes such as the degradation of organic compounds and the oxidant capacity. However, it is still unknown whether the functioning of airborne microorganisms in clouds is specific and differs from the rest of the atmosphere; this question was investigated here. We developed a metagenomic/metratranscriptomic approach to investigate the in-situ functioning of airborne microbial communities and decipher its environmental drivers, notably the impacts of the presence of condensed water in clouds. Aerosol and clouds samples were collected from puy de Dôme mountain summit (1465 m asl, France) using series of high flow rate impingers, into a fixative agent to preserve nucleic acids (DNA and RNA), i.e. the identity and instantaneous functional signature of organisms. A bioinformatics pipeline was developed specifically to analyze these unprecedented and complex datasets. Comparative analyses revealed that clouds are genuine oases for living microorganisms in the atmosphere: although their microbial biodiversity is similar as that during clear atmospheric situations, droplets provide shelters especially against oxidative stress, which is found to characterize the metabolic functioning of airborne microbes in dry aerosols. The presence of condensed water boosts many biological functions, and functions related with starvation toward carbon and nitrogen notably indicate increased biological needs and evidence the existence of numerous interactions with chemical processes and atmospheric biogeochemical cycles. Regarding microbial ecology, the reactivation of metabolic functions in airborne microorganisms transiting through clouds could facilitate their settlement in their new environment.

The occurrence of micro and nano plastics has been reported in every environmental compartment including marine and freshwaters, soils and sediments, air and atmospheric precipitations. Recent evidence showing the presence of airborne microplastics in remote ecosystems highlights the extent of this pollution. The atmospheric transportation and the distribution of airborne microplastics still need to be better documented to understand the dynamic of microplastic transfer between ecosystems.While most studies dedicated to the analysis of microplastics in the air use a passive sampling methodology through atmospheric deposition we developed an original stainless device to sample large volumes of air with high debit (2000 L/min) providing a fast sampling of aerosols within a small localized area. An optimized sampling protocol has been deployed in the North Western Mediterranean Sea from the Expedition 7th Continent (E7C) boat. 19 sampling sites have been studied during the E7C expedition in September-October 2019, including measurements in port and coastal areas as well as offshore environments. The analysis of micro/nano plastics was carried out using pyrolysis coupled with gas chromatography and tandem mass spectrometry (Py-GC-MS/MS). This approach allowed us to evaluate the concentrations of micro and nano plastics present in the samples for 5 types of plastics (polypropylene, polystyrene, polymethyl methacrylate, polyethylene terephthalate and polycarbonate) and for 2 size ranges (5-50μm and

Metabolically active microorganisms are increasingly acknowledged as actors of cloud chemical reactivity able to use organic compounds present in clouds (e.g. organic acids, aldhedydes) for their metabolism (Vaïtilingom et al., 2013). Uncharacterized biological activity may play a major role especially during the night, while during daytime the abiotic degradation of organic compounds would be driven and dominated by hydroxyl radical (•OH) chemistry (Vaïtilingom et al., 2011). To better understand and predict the impact of biological activity on atmospheric chemical reactivity, the metabolic pathways of the whole cloud microbiome and their modulations by environmental conditions (temperature, light, oxidants) must now be assessed.The METACLOUD project addresses metabolic acclimatation of cloud microorganisms under two contrasted situations simulating a summer day (17°C, with solar light and presence of hydrogen peroxide) and a winter night (at 5°C, in the dark and without hydrogen peroxide). A focus is made on formaldehyde assimilations as this compound is a key intermediate both in cloud radical chemistry and in many C1 biological pathway, using fluxomics (LC-HRMS and IC-HRMS) on 13C-formaldehyde supplemented samples. Experiments were conducted in specially designed photobioreactors, either on (1) freshly sampled cloud water from the research station at the top of the puy de Dôme station (1465m asl, PUY, France) including naturally present microorganisms, or (2) an artificial consortium assembled from microbial strains isolated from cloud water sampled at PUY and resuspended in an artificial medium mimicking the composition of marine cloud water (major inorganic and organic compounds).Metatranscriptomes and metabolomes indicate metabolic acclimations of the cloud microbiome to model summer/winter conditions, especially linked with fatty acid regulation and central metabolism (e.g. citrate cycle). First results with 13C-formaldehyde showed carbon incorporation from this molecule into several classes of metabolites (e.g. nucleotides, amino acids, central metabolites), illustrating the complex biological fate of this compound in the environment. The data will be used to implement biological activity on cloud chemistry models. Vaïtilingom M. et al. (2011) Atmospheric chemistry of carboxylic acids: microbial implication versus photochemistry. Atmos. Chem. Phys. 11, 8721-8733. doi: 10.5194/acp-11-8721-2011.Vaïtilingom M. et al. (2013) Potential impact of microbial activity on the oxidant capacity and organic carbon budget in clouds. Proc. Nat. Acad. Sci. USA 110, 559-564. doi: 10.1073/pnas.1205743110.

International audience; Plastics are associated with a worldwide pollution crisis, with strong negative impacts on both terrestrial and aquatic ecosystems. In marine environments, various organisms are colonizing plastic debris, but few studies have focused on fungal communities despite their non-trivial ecological roles in the marine environment. In this study, different types of plastics (biodegradable and conventional) immersed in marine natural environments and under laboratory controlled settings were collected after long-term colonization. Using a metabarcoding approach targeting two genetic markers, namely, the ITS2 region and the V4 hypervariable region of the 18S rRNA gene, we highlighted that fungal communities associated with plastic polymers were distinct from those found in the surrounding seawater. They also differed significantly between sampling locations and the nature of immersed polymers, indicating that fungal colonization was impacted by the sites and types of plastics, with clear dissimilarities between conventional and biodegradable polymers. Specifically for the conventional PVC polymer (Polyvinyl chloride), we also observed the successive stages of biofilm development and maturation after long-term immersion in seawater. A noticeable change in the fungal communities was observed around 30-40 days in natural settings, suggesting a colonization dynamic likely associated with a transition from biofilm formation to distinct communities likely associated with biofouling. Overall, this study strengthens the idea that the fungal kingdom is an integrated part of the "plastisphere".

International audience; Densities of pure furan, toluene, 1-octanol, n-hexane and, of binary liquid mixtures containing furan, has been measured from 303.15 K to 383.15 K at pressures up to 1.6 MPa, using a vibrating tube densimeter. Excess molar volumes have been calculated from the densities with an average standard uncertainty 0.02 cm 3 .mol-1. Excess molar enthalpies of the binary mixtures were measured at temperatures ranging from 313.15 to 383.15 K at 0.5 MPa and/or 1.0 MPa, using flow mixing calorimeter. The average standard uncertainty on the whole measurements is less than 1%. The excess molar properties derived from experimental data were correlated using a Redlich-Kister polynomial functions, NRTL activity coefficient model and Prigogine Flory Patterson modelling is described and used to correlate the data.

Biodegradation is competitive with photochemistry, especially in summer and at night. Formic acid is the most impacted compound.

International audience; WSiC:H coatings were elaborated by reactive magnetron sputtering of a W target in an Ar/Si(CH3)4 plasma assisted by ECR microwave sources. Such coatings can be very interesting for optical or mechanical applications. The development of these coatings is based on the confrontation between in-situ diagnostics of the reactive plasma phase and material characterization of the resulting coatings. The investigation by optical emission spectroscopy of the different phenomena occurring in the reactive plasma reveals that there is a precursor flow rate range where W particles can be favored in the reactive plasma, to promote the development of composite coatings based on a SiC:H matrix, in which W-containing particles or aggregates are present. Material charac-terization such as Scanning Electron Microscopy, Ion Beam Analysis and X-ray Photoelectron Spectroscopy are used to study the impact of the plasma phase on the microstructure and chemical composition of the deposited materials.

International audience; Nanostructure control is an important issue when using electroactive materials in energy conversion and storage devices. In this study, we report various methods of synthesis of nanostructured copper (II) hydroxide nitrate (Cu-2(OH)(3)NO3) with a layered hydroxide salt (LHS) structure using various synthesis methods and investigate the correlation between nanostructure, morphology, and their pseudocapacitive electrochemical behavior. The variations in nanostructure size and morphology were comprehensively explored by combining X-ray diffraction (XRD) and scanning electron microscopy (SEM), while the electrochemical activity was characterized using cyclic voltammetry. We demonstrate that Cu-2(OH)(3)NO3-LHS nanostructured submicron particles produced by alkaline precipitation with 88% of the copper cations can cycle with a two-electron redox process. Unfortunately, the electroactivity decreases rapidly from the first cycle due to the occurrence of structural transformations and subsequent electrochemical grinding. However, samples obtained by ultrasonication and microwave synthesis, two original synthesis methods for LHS materials, formed of nanosized crystalline domains agglomerated in micron-sized particles, represent a good compromise between capacity and cyclability. Moreover, by using pair distribution function analysis on electrode materials after repeated cycling, we were able to follow the chemical and structural changes occurring in Cu-2(OH)(3)NO3 materials during electrochemical cycling with first a quick transformation to Cu2O and then the appearance of Cu metal and copper acetate Cu(II)(2)(O2CCH3)(4)center dot 2H(2)O.

Bismuth oxyfluoride films were successfully deposited by reactive magnetron sputtering in different Ar/O2/CF4 gas mixtures. Films deposited with a reactive gas ratio (Rf), which is the O2 to (O2 + CF4) flow rates ratio, ranging between 0 and 0.5 consist of two phases, BiO0.5F2 and metallic bismuth (Bi o); whereas for higher Rf the metallic phase disappears. The content of metallic Bi into oxyfluoride matrix can be tuned by Rf, but also by the target applied power or by varying only one reactive gas flow rate. By increasing the film thickness, the composition stays stable but the phase crystallization is enhanced. Hence, we succeed to form in one-step Bi/BiO0.5F2 heterojunctions, where the metal presence improves the light absorption, the photogenerated carrier separation, and thus the photocatalytic efficiency for MO degradation in water. For all these conditions, the film obtained with Rf = 0.3 and td = 20 min seems to correspond to an optimal composition. Indeed, 90 % of MO was degraded after 2 hours of irradiation in the presence of this film, which is stable after 3 photocatalytic cycles (≈ 9 hours). This heterojunction is also efficient to photoreduce CO2 with a photoprodcution rate of 25 micro-mol/h/g and a selectivity for CO at 70%.

International audience; The Plateau des Dômes overhangs the Limagne graben by several hundred metres and represents the basement of a Quaternary volcanic chain oriented north-south, the Chaîne des Puys (CdP), consisting of about 80 volcanic edifices spread linearly over thirty kilometers. Since its final emersion in the late Cretaceous, the Plateau des Dôme has been mainly affected by two tectonic events: the formation of the West European Rift (ROE), with its associated volcanism, and a late surrection that is still ongoing. To unravel the Tertiary and Quaternary geological history of the Plateau, a structural approach was defined. At the scale of the Massif central, four families of Variscan crustal faults can be described : 1. the Sillon Houiller family oriented N20E (dir.SH), 2. the Cévennes fault family oriented NE-SW (dir.C), 3. the Villefort fault fa­mily oriented N160-170E (dir.V) and 4. the Armorican family, which oscillates between N110E and N140E (dir.A) due to the orientation of the North and South Armorican Shear Zone. This network of crustal faults can be observed at any scale.It is shown that the Plateau des Dômes is crossed by such a network of variscan faults, which was reactivated during the Tertiary and Quaternary tectonic events occurring in the studied zone. No new faults were created in response to the different stress patterns that prevailed in the Tertiary and Qua­ternary periods.The main conclusions of this study can be summarized as follows :1. The Variscan basement of the Plateau des Dômes was tilted westwards at the end of the Eocene by the formation of the Olby half-graben controlled by the reactivation of the Pontgibaud fault [FdP (dir.SH)]. It was limited to the east by the Limagne fault (FdL), which reactivated two Variscan directions (dir.SH and dir.V), the only two compatible with the east-west extension. At that time, the future plateau was emerged, but at an altitude close to sea level.2. The cessation of the FdP and the continued activity of the FdL in the Oligocene caused the eastern edge of the future plateau to be dissected and lowered down by the activation of FdL's secondary (dir.SH) faults. The future plateau remained close to sea level. The main outlines of its present topography were acquired at the end of the sedimentation period.3. The plateau was uplifted shortly before the emission of the last Montdorian lava flows, dated at 3.5/3 Ma. To the east, the FdL was not reactivated during the regional uplift and the Plateau des Dômes appears as such due to erosion of the Limagne weak sediments, which cleared the fault scarp. The Plateau des Dômes is part of a larger ensemble (i.e. a larger plateau) bounded by the Morge dir.C fault to the north and the Sillon Houiller to the west. Through the coeval reactivation of these two faults, this large north-western quadrant has undergone differential uplift bringing it to a high position relative to areas further north and west. To the south, the Plateau des Dômes is dominated by the large Monts Dore stratovolcano. In this sector, a series of parallel dir.A faults, oriented N110E, as well as the reactivation of the Nébouzat fault, have ensured the differential surrection of the basement in a way similar to successive steps of a staircase.4. The volcanoes of the CdP are aligned along a main fault (the Beauregard fault), which is the backbone of the chain, and along several secondary faults, dir.SH to the NE and dir.A to the SE, all connected to the main fault. The lava flows follow paleo valleys that were dug along the weak zones constituted by the Variscan faults. The north of the plateau, dominated by dir.SH faults, exhibits lava flows that are generally oriented NE-SW, in sharp contrast to the south, dominated by dir.A faults, where the flows are oriented NW-SE.; Le Plateau des Dômes surplombe le graben de la Limagne de plusieurs centaines de mètres et supporte une chaîne volcanique quaternaire orientée nord-sud, la Chaîne des Puys (CdP), constituée d’environ 80 édifices répartis linéairement sur une trentaine de kilomètres. Ce plateau est traversé par un réseau de failles crustales où se reconnaissent les grandes familles varisques, représentées dans le Massif central par des failles emblématiques telles que le Sillon Houiller, la Faille des Cévennes ou la Faille de Villefort. Depuis son émersion définitive vers la fin du Crétacé, le Plateau des Dômes a été principalement affecté par deux événements tectoniques : la formation du Rift Ouest Européen (ROE), avec son volcanisme associé, et une surrection tardive qui se poursuit actuellement.Par une synthèse des données existantes et une réappréciation des cartes géologiques et de l’analyse de la topographie (analyse des MNT : Modèles Numériques de Terrain), cet article montre que la structuration tertiaire et quaternaire du Plateau des Dômes s’est entièrement effectuée par la réactivation de quelques failles varisques majeures qui ont 1) permis le basculement du socle lors de la formation des grabens, 2) assuré sa surrection différentielle par rapport à d’autres secteurs limitrophes et 3) contrôlé l’ascension des magmas vers la surface. Une évolution structurale du plateau est proposée résumant les étapes majeures depuis l’Eocène.

International audience; The reaction catalyzed by ubiquitous thiamine pyrophosphate-dependent transketolase engaged in cells in the pentose phosphate pathway can be applied in vitro to the cleavage of aliphatic α-hydroxy ketones with thermostable transketolase variants from Geobacillus stearothermophilus obtained through rational design. The simple variant F435I gave the best activity toward (3S)-1,3-dihydroxyhexan-2-one 3, leading to the corresponding product with 92% yield after only 2 h of reaction time. Three triple variants H102L/H474 (S, G, or A)/F118I were found to cleave (±)-4-hydroxyhexan-3-one 6, giving the corresponding product with 90, 82, and 79% yield, respectively, after 24 h, whereas wild-type transketolase was almost ineffective. This biocatalytic strategy offers a promising one-step alternative to other multienzyme or chemical ways for the cleavage of aliphatic α-hydroxy ketones.

International audience; Sol-gel based layers doped with Rhodamine B phosphors (RB) were directly microstructured to produce sub-lambda 2D gratings, using nanoimprint lithography. Such an approach enables the simplification of technological processes, since no further etching process is required, which reduces considerably the number of technological steps and thus production costs. Surface microstructuring improved fluorophore emission in the visible range. Demonstrations were performed experimentally and samples were characterized using angle-resolved fluorescence. The emissions measured on microstructured luminescent coatings were 3–4 times higher, depending on the angle of observation, than those recorded on flat surfaces. This technological approach is very promising for the next generation of low-cost, high-performance anti-counterfeiting marking processes and for the traceability of objects based on unique optical effects

Eighteen free amino acids (FAAs) were quantified in cloud water sampled at the Puy de Dôme station (PUY – France) during 13 cloud events. This quantification has been performed without concentration or derivatization, using liquid chromatography hyphened to mass spectrometry (LC-MS) and the standard addition method to correct for matrix effects. Total concentrations of FAAs (TCAAs) vary from 1.2 to 7.7 µM, Ser (serine) being the most abundant AA (23.7 % on average) but with elevated standard deviation, followed by glycine (Gly) (20.5 %), alanine (Ala) (11.9 %), asparagine (Asn) (8.7 %), and leucine/isoleucine (Leu/I)​​​​​​​ (6.4 %). The distribution of AAs among the cloud events reveals high variability. TCAA constitutes between 0.5 and 4.4 % of the dissolved organic carbon measured in the cloud samples. AA quantification in cloud water is scarce, but the results agree with the few studies that investigated AAs in this aqueous medium. The environmental variability is assessed through a statistical analysis. This work shows that AAs are correlated with the time spent by the air masses within the boundary layer, especially over the sea surface before reaching the PUY. The cloud microphysical properties' fluctuation does not explain the AA variability in our samples, confirming previous studies at the PUY. We finally assessed the sources and the atmospheric processes that potentially explain the prevailing presence of certain AAs in the cloud samples. The initial relative distribution of AAs in biological matrices (proteins extracted from bacterial cells or mammalian cells, for example) could explain the dominance of Ala, Gly, and Leu/I. AA composition of aquatic organisms (i.e., diatom species) could also explain the high concentrations of Ser in our samples. The analysis of the AA hygroscopicity also indicates a higher contribution of AAs (80 % on average) that are hydrophilic or neutral, revealing the fact that other AAs (hydrophobic) are less favorably incorporated into cloud droplets. Finally, the atmospheric aging of AAs has been evaluated by calculating atmospheric lifetimes considering their potential transformation in the cloud medium by biotic or abiotic (mainly oxidation) processes. The most concentrated AAs encountered in our samples present the longest atmospheric lifetimes, and the less dominant ones are clearly efficiently transformed in the atmosphere, potentially explaining their low concentrations. However, this cannot fully explain the relative contribution of several AAs in the cloud samples. This reveals the high complexity of the bio-physico-chemical processes occurring in the multiphase atmospheric environment.

We present here the results obtained during an intensive field campaign conducted in the framework of the French “BIO-MAÏDO” (Bio-physico-chemistry of tropical clouds at Maïdo (Réunion Island): processes and impacts on secondary organic aerosols' formation) project. This study integrates an exhaustive chemical and microphysical characterization of cloud water obtained in March–April 2019 in Réunion (Indian Ocean). Fourteen cloud samples have been collected along the slope of this mountainous island. Comprehensive chemical characterization of these samples is performed, including inorganic ions, metals, oxidants, and organic matter (organic acids, sugars, amino acids, carbonyls, and low-solubility volatile organic compounds, VOCs). Cloud water presents high molecular complexity with elevated water-soluble organic matter content partly modulated by microphysical cloud properties. As expected, our findings show the presence of compounds of marine origin in cloud water samples (e.g. chloride, sodium) demonstrating ocean–cloud exchanges. Indeed, Na+ and Cl− dominate the inorganic composition contributing to 30 % and 27 %, respectively, to the average total ion content. The strong correlations between these species (r2 = 0.87, p value: < 0.0001) suggest similar air mass origins. However, the average molar Cl-/Na+ ratio (0.85) is lower than the sea-salt one, reflecting a chloride depletion possibly associated with strong acids such as HNO3 and H2SO4. Additionally, the non-sea-salt fraction of sulfate varies between 38 % and 91 %, indicating the presence of other sources. Also, the presence of amino acids and for the first time in cloud waters of sugars clearly indicates that biological activities contribute to the cloud water chemical composition. A significant variability between events is observed in the dissolved organic content (25.5 ± 18.4 mg C L−1), with levels reaching up to 62 mg C L−1. This variability was not similar for all the measured compounds, suggesting the presence of dissimilar emission sources or production mechanisms. For that, a statistical analysis is performed based on back-trajectory calculations using the CAT (Computing Atmospheric Trajectory Tool) model associated with the land cover registry. These investigations reveal that air mass origins and microphysical variables do not fully explain the variability observed in cloud chemical composition, highlighting the complexity of emission sources, multiphasic transfer, and chemical processing in clouds. Even though a minor contribution of VOCs (oxygenated and low-solubility VOCs) to the total dissolved organic carbon (DOC) (0.62 % and 0.06 %, respectively) has been observed, significant levels of biogenic VOC (20 to 180 nmol L−1) were detected in the aqueous phase, indicating the cloud-terrestrial vegetation exchange. Cloud scavenging of VOCs is assessed by measurements obtained in both the gas and aqueous phases and deduced experimental gas-/aqueous-phase partitioning was compared with Henry's law equilibrium to evaluate potential supersaturation or unsaturation conditions. The evaluation reveals the supersaturation of low-solubility VOCs from both natural and anthropogenic sources. Our results depict even higher supersaturation of terpenoids, evidencing a deviation from thermodynamically expected partitioning in the aqueous-phase chemistry in this highly impacted tropical area.

The sorption of drugs onto their contents is a known phenomenon that is difficult to analyse precisely. The purpose of this study was to present a non-invasive method for locating and quantifying sorption phenomena using radiopharmaceuticals. Radiopharmaceutical are medicines armed with a radionuclide enabling quantification and imaging using dedicated scanners. The sorption of nine different radiopharmaceuticals on 2- and 3-part syringes was investigated. These syringes were filled with the studied radiopharmaceutical solutions and stored immobile for 3 h. At different times ranging from 0 to 180 min, 10 µL were taken from the syringes and the radioactivity of these samples was determined by a gamma counter. 5 radiopharmaceuticals exhibited no significant sorption at any time point in both 2 and 3-parts syringes, but 4 radiopharmaceuticals exhibited sorption losses varying from 20 to 33% after 3 h contact with 3-part-syringes, but no sorption on 2-part syringes at any time point. [99mTc]Tc-tetrofosmine Single Photon Emission Computed Tomography/Computed Tomography imaging indicated clearly that the interactions were located on the rubber plunger of the 3-part-syringes. The specific nature of radiopharmaceuticals allowed their use as an innovative method to quantify and localize drug sorption phenomena.

Among the nanomaterials reported in the literature, layered double hydroxides (LDHs) are considered promising for the electrochemical sensor technology. Transition metal-based layered double hydroxides (TM-LDHs) show excellent electrocatalytic properties that facilitate redox reactions with analytes, e.g. H2O2, glucose or glyphosate. Elaboration of porous nano-structures with TM-LDHs nanosheets on the electrode surface allows a rapid diffusion of the analytes and a good accessibility of the TM active sites. An association of TM-LDHs with conductive materials, e.g. graphene or metal nanoparticles (M-NPs), improves the electronic conductivity in the LDH-based composites and also the electrocatalytic activity. With a selection of recent publications, the present mini-review aims to discuss about the specific electrocatalytic role played by TMs (Ni, Co, Cu, Mn and Fe) present in the LDH layers on the performance (sensitivity and detection limit) of these TM-LDHs-based sensors.

We report for the first time the elaboration of an original ZnO nanowire (NW) architecture entirely based on a soft chemistry approach and its thorough assessment through optical measurements and electromagnetic simulations. This architecture relies on the photo-imprinting of a sol-gel ZnO-based photosensitive seed layer combined with the subsequent localized hydrothermal growth of ZnO NWs. We firstly show how optimization of the elaboration protocol leads to uniform and reproducible linear and periodic gratings of ZnO NWs with a width / pitch of 2 µm / 4 µm. For reference, full-covered samples (NWs coating) have also been elaborated from a non-imprinted seed layer. It has been evidenced through morphological study that NW gratings present a peculiar profile similar to a hedgehog. Standard and angle-resolved photoluminescence measurements performed on both kinds of samples are then presented. These optical characterizations demonstrate that ZnO NW visible emission is strongly modified by the presence of NW gratings and that its red part is directionally extracted and increased by a factor up to 2. We present finally electromagnetic simulations performed for both samples which highlight the role of the gratings acting as coupled microcavities that boost the ZnO emission thanks to light localization and diffractive mechanisms. It enables the extraction of the resonant photons towards some specific angles and at given wavelengths.

International audience; Background While the effect of anti-TNFs on postoperative outcomes in patients with Crohn's disease (CD) has been widely studied, the impact of vedolizumab and ustekinumab on the risk of postoperative complications remains poorly known. Methods All consecutive patients who underwent intestinal resection for CD between July 2014 and April 2022 within 22 French centers were included in a retrospective cohort. The risk of early post-operative complications (≤30days) in patients exposed to biologics was compared to patients not exposed by logistic regression and propensity score-matched analysis adjusted for age, previous intestinal resection, corticosteroids or immunosuppressants exposure, disease activity, presence of abscess, urgent surgery and initial stoma (preoperative contra-indication to anastomosis). Results Among the 1201 patients included, respectively 491 (41%), 76 (6.3%) and 57 (4.7%) were exposed to anti-TNFs, ustekinumab, or vedolizumab within six months before surgery. A total of 317 (26.4%) patients had at least one complication of which 123 (38%) were considered as severe (DINDO III/IV). New surgery was necessary in 69 (5.7%) patients and secondary stoma in 23 (1.9%). Three deaths were observed (0.25%). The rates of overall complications in patients not exposed to biologics, exposed to anti-TNFs, ustekinumab or vedolizumab were respectively 26.1%, 25.1%, 34.7% and 29.8%. The risks of intra-abdominal infectious complications in these four groups were respectively 13.5%, 11.1%, 13.3% and 8.8%. In multivariate analysis, age [OR, 1.02 (1.01-1.04); p=0.004], disease activity [OR, 8.36 (1.79 – 149); p=0.037], the presence of an abscess [OR, 2.01 (1.25-3.20); p=0.004] and initial stoma [OR, 1.70 (1.10 –2.61); p=0.016] were significantly associated with intra-abdominal infectious complications. Conversely, preoperative enteral nutrition [OR, 0.12 (0.01 -0.59); p=0.040] was associated with a reduction in this risk. Exposure to anti-TNFs [OR, 0.80 (0.51-1.24); p=0.31], ustekinumab [OR, 1.17 (0.39-3.51); p=0.78] and vedolizumab [OR, 1.28 (0.32-5.17); p=0.72] within the 3 months before surgery were not associated with the risk of intra-abdominal infectious complications. Similar results were observed in patients exposed to these treatments in the month before surgery. Conclusion In this large cohort, a quarter of patients operated on for CD presented an early postoperative complication and 10% a severe complication. Preoperative exposure to anti-TNFs, vedolizumab or ustekinumab was not associated with an increased risk of early postoperative complications. Preoperative enteral nutrition was associated with a reduced risk of intra-abdominal infectious complication.

International audience; In this study, the goal was to compatibilize flax natural fibers (which are inherently polar) with mostly dispersive polymers, while proposing a way to recover greenhouse gases or refrigerants such as CF4 or C2F5H. Such gases exhibit a high global warming potentials (GWPs) and their recovery at the end of their lifecycle is difficult. Therefore, these two representative problematic gases were used as plasma precursor to graft fluorine atoms onto the flax fiber surface. Chemical investigation (FT-IR, 19F NMR and XPS spectroscopies), demonstrates the covalent grafting of fluorine atoms at the fiber surface, that opens the route of tailoring the surface chemistry of flax fibers. These modifications induced a decrease of the fiber polarity, which allows the treated fibers to become perfectly compatible with mostly dispersive polymer. Moreover, both mechanical properties and fluorine release during fibers combustion were investigated and any negative impact was evidenced. Therefore, thanks to the plasma fluorination, the gap between the surface energies of the fibers and mostly dispersive polymer matrix was reduced improving the wettability of the fibers through an eco-friendly way. This phenomenon promising an improvement in the mechanical performance of eco-composites reinforced with these fluorinated fibers.

International audience; By selecting two electroactive species immobilized in a layered double hydroxide backbone (LDH) host, one able to act as a positive electrode material and the other as a negative one, it was possible to match their capacity to design an innovative energy storage device. Each electrode material is based on electroactive species, riboflavin phosphate (RF) on one side and ferrocene carboxylate (FCm) on the other, both interleaved into a layered double hydroxide (LDH) host structure to avoid any possible molecule migration and instability. The intercalation of the electroactive guest molecules is demonstrated by X-ray diffraction with the observation of an interlayer LDH spacing of about 2 nm in each case. When successfully hosted into LDH interlayer space, the electrochemical behavior of each hybrid assembly was scrutinized separately in aqueous electrolyte to characterize the redox reaction occurring upon cycling and found to be a rapid faradic type. Both electrode materials were placed face to face to achieve a new aqueous battery (16C rate) that provides a first cycle-capacity of about 7 mAh per gram of working electrode material LDH/FCm at 10 mV/s over a voltage window of 2.2 V in 1M sodium acetate, thus validating the hybrid LDH host approach on both electrode materials even if the cyclability of the assembly has not yet been met.

International audience; Bioaerosols have impacts on atmospheric processes, as well as ecosystem and human health. Common bioaerosol collection methods include impaction, liquid impingement, filtration, and electrostatic precipitation. These methods are used by active samplers that require an air mover and power, but this requirement can also represent a major constraint in field studies. Alternatively, passive samplers do not require power and can operate for long times. In this study, the Rutgers Electrostatic Passive Sampler (REPS), which captures particles by electrostatic attraction and gravitational settling, was deployed at the summit of puy de Dôme (1465 m a.s.l., France) alongside an active PM10 sampler (~1000 L min-1) collecting aerosols on a quartz fiber filter. The diversity of the airborne bacteria captured by both samplers across six weekly sampling periods was examined by 16S rRNA gene amplicon sequencing. The dominant phyla observed by both samplers were similar and included Firmicutes, Proteobacteria, and Actinobacteriota. Overall, 12 to 63% of the total bacterial richness at the genus level was shared between the two samplers, depending upon a paired sample, i.e., sampling week. The PM10 sampler and REPS detected the same dominant genera, including Lysinibacillus and Sphingomonas, although their relative abundances for each paired sampler varied. The observed bacterial richness and diversity, as estimated through Shannon's and Simpson's indexes, were significantly greater in REPS samples compared to the PM10 samples. The results suggest that REPS could be used for simple and convenient sampling of bioaerosols, especially in remote areas and other locations with limited power access.

International audience; Here, we present an immobilized enzyme cascade in a basket-type reactor allowing a one-pot, two-step enzymatic synthesis of L-erythrulose from D-serine and glycolaldehyde. Three enzymes, D-amino acid oxidase from Rhodotorula gracilis (DAAORg), catalase from bovine liver (CAT), and transketolase from Geobacillus stearothermophilus (TKgst) were covalently immobilized on silica monolithic pellets, characterized by an open structure of interconnected macropores and a specific surface area of up to 300 m2/g. Three strategies were considered: (i) separate immobilization of enzymes on silica supports ([DAAO][CAT][TK]), (ii) co-immobilization of two of the three enzymes followed by the third ([DAAO+CAT][TK]), and (iii) co-immobilization of all three enzymes ([DAAO+CAT+TK]). The highest L-erythrulose concentrations were observed for the co-immobilization protocols (ii) and (iii) (30.7 mM and 29.1 mM, respectively). The reusability study showed that the best combination was [DAAO + CAT][TK], which led to the same level of L-erythrulose formation after two reuse cycles. The described process paves the way for the effective synthesis of a wide range of α-hydroxyketones from D-serine and suitable aldehydes.

International audience; In the present work, PVDF - Fe3O4 nanoparticle (NP) nanocomposite films were produced using the electrospinning method. We investigated the effect of NP size on the film's morphology (fiber size), mechanical properties, and physical properties (β-phase percentage). Surprisingly, while nanoparticle size acts as an enhancer for mechanical properties, it appeared to act as an inhibitor in terms of its effects on the crystallization of the β-polymorph. This result seemed in discordance with many previous results. A focus on local interactions between the NP surface chemistry and PVDF chains revealed the influence of grafted ligands at the nanoparticle surface on the crystallization of the piezoelectric phase of PVDF. The results from the molecular dynamics (MD) simulations for systems of PVDF chains with slabs of –OH and oleic acid-grafted magnetite, showed that the probability of beta phase configuration decreases when the nanoparticles are functionalized with oleic acid and becomes more probable for –OH terminated magnetite. These computational results are in accordance with our experimental results. To verify this hypothesis, we prepared films with washed nanoparticles to eliminate the excess oleic acid that acts as a β-polymorph inhibitor. As a result, the amount of β-phase obtained for washed nanoparticles increased and the difference in the amount of β-phase between the different samples decreased. Moreover, when heated, the films of nanocomposite with washed NP developed more β-phase for smaller sizes of nanoparticles. At 140 °C, isomerization occurred, and oleic acid was converted into elaidic acid, reducing the steric hindrance, and promoting the interaction between PVDF chains and the surface of the nanoparticles. This isomerization reaction seems to be an enhancer of the α- to β-phase transition. Our results prove that optimizing multiple properties in nano-reinforced polymers requires consideration of different aspects, such as NP size, surface chemistry, and processing methods.Our results based on mixed experimental and modeling approach proved the usefulness of simulation in understanding and guiding our experimental results. Our results suggest that for enhancing piezoelectric properties in PVDF magnetite nano-composites, the chemistry and the molecular morphology of the grafted ligands when combined with NP size could lead to multi-properties enhancement simultaneously.