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International audience; One of the best approaches for improving the assessment of metal toxicity in aquatic organisms is to study their organotropism (i.e., the distribution of metals among organs) through a dynamical approach (i.e., via kinetic experiments of metal bioaccumulation), to identify the tissues/organs that play a key role in metal regulation (e.g., storage or excretion). This study aims at comparing the organ-specific metal accumulation of a non-essential (Cd) and an essential metal (Zn), at their environmentally relevant exposure concentrations, in the gammarid Gammarus fossarum. Gammarids were exposed for 7 days to 109 Cd-or 65 Znradiolabeled water at a concentration of 52.1 and 416 ng.L-1 (stable equivalent), respectively, and then placed in clean water for 21 days. At different time intervals, the target organs (i.e., caeca, cephalons, intestines, gills, and remaining tissues) were collected and 109 Cd or 65 Zn contents were quantified by gamma-spectrometry. A one-compartment toxicokinetic (TK) model was fitted by Bayesian inference to each organ/metal dataset in order to establish TK parameters. Our results indicate: i) a contrasting distribution pattern of concentrations at the end of the accumulation phase (7 th day): gills > caeca ≈ intestines > cephalons > remaining tissues for Cd and intestines > caeca > gills > cephalons > remaining tissues for Zn; ii) a slower elimination of Cd than of Zn by all organs, especially in the gills in which the Cd concentration remained constant during the 21-day depuration phase, whereas Zn concentrations decreased sharply in all organs after 24 h in the depuration phase; iii) a major role of intestines in the uptake of waterborne Cd and Zn at environmentally relevant concentrations.

Cell compatibility of biomaterials is one of the most important issues in Tissue Engineering. It is affected by the catalyst, the chemical composition and the surface topography of the material. Ou...

International audience; A biomonitoring approach based on a single model species cannot be representative of the contaminations impacts on the ecosystem overall. As part of the Interreg DIADeM program (“Development of an integrated approach for the diagnosis of the water quality of the River Meuse”), a study was conducted to establish the proof of concept that the use of a multispecies active biomonitoring approach improves diagnostic of aquatic systems. The complementarity of the biomarker responses was tested in four model species belonging to various ecological compartments: the bryophyte Fontinalis antipyretica, the bivalve Dreissena polymorpha, the amphipod Gammarus fossarum and the fish Gasterosteus aculeatus. The species have been caged upstream and downstream from five wastewater treatment plants (WWTPs) in the Meuse watershed. After the exposure, a battery of biomarkers was measured and results were compiled in an Integrated Biomarker Response (IBR) for each species. A multispecies IBR value was then proposed to assess the quality of the receiving environment upstream the WWTPs. The effluent toxicity was variable according to the caged species and the WWTP. However, the calculated IBR were high for all species and upstream sites, suggesting that the water quality was already downgraded upstream the WWTP. This contamination of the receiving environment was confirmed by the multispecies IBR which has allowed to rank the rivers from the less to the most contaminated. This study has demonstrated the interest of the IBR in the assessment of biological impacts of a point-source contamination (WWTP effluent) but also of the receiving environment, thanks to the use of independent references. Moreover, this study has highlighted the complementarity between the different species and has emphasized the interest of this multispecies approach to consider the variability of the species exposition pathway and sensibility as well as the mechanism of contaminants toxicity in the final diagnosis.

International audience; The use of freshwater invertebrates for biomonitoring has been increasing for several decades, but little is known about relations between external exposure concentration of metals and their biodistribution among different tissues. One and multi-compartments toxicokinetic (TK) models are powerful tools to formalize and predict how a contaminant is bioaccumulated. The aim of this study is to develop modeling approaches to improve knowledge on dynamic of accumulation and fate of Cd and Hg in gammarid's organs. Gammarids were exposed to dissolved metals (11.1 +/- 1.2 mu g.L-1 of Cd or 0.27 +/- 0.13 mu g.L-1 of Hg) before a depuration phase. At each sampling days, their organs (caeca, cephalon, intestine and remaining tissues) were separated by dissection before analyses. Results allowed us to determine that i) G. fossarum takes up Cd as efficiently as the mussel M. galloprovincialis, but eliminates it more rapidly, ii) organs which accumulate and depurate the most, in terms of concentrations, are caeca and intestine for both metals; iii) the one-compartment TK models is the most relevant for Hg, while the multi-compartments TK model allows a better fit to Cd data, demonstrating dynamic transfer of Cd among organs.

Multiple reaction monitoring (MRM) mass spectrometry is emerging as a relevant tool for measuring customized molecular markers in freshwater sentinel species. While this technique is typically used for the validation of protein molecular markers preselected from shotgun experiments, recent gains of MRM multiplexing capacity offer new possibilities to conduct large-scale screening of animal proteomes. By combining the strength of active biomonitoring strategies and MRM technologies, this study aims to propose a new strategy for the discovery of candidate proteins that respond to environmental variability. For this purpose, 249 peptides derived from 147 proteins were monitored by MRM in 273 male gammarids caged in 56 environmental sites, representative of the diversity of French water bodies. A methodology is here proposed to identify a set of customized housekeeping peptides (HKPs) used to correct analytical batch effects and allow proper comparison of peptide levels in gammarids. A comparative analysis performed on HKPs-normalized data resulted in the identification of peptides highly modulated in the environment and derived from proteins likely involved in the environmental stress response. Overall, this study proposes a breakthrough approach to screen and identify potential proteins responding to relevant environmental conditions in sentinel species.

International audience; Polymeric, biodegradable, microspheres (MS) presenting a biomimetic surface of extracellular matrix (ECM) proteins are currently used for transporting cells and/or encapsulated proteins for regenerative medicine studies. They can be made of (lactic-co-glycolic acid) (PLGA) or of a more hydrophilic PLGA-P188 (Poloxamer188)-PLGA polymer allowing for the complete release of the therapeutic proteins. They promote stem cell adhesion, cell survival and differentiation after transplantation. Although the biological effectiveness of these microcarriers is established, a detailed understanding of the protein and cell interactions with the microcarrier surface remain unclear due to a lack of information of their surface properties. The aim of this study was to characterize the physicochemical properties of two polymeric MS systems and determine the effect of laminin and poly-D-lysine coated microcarriers on stem cell adhesion, survival and neuronal differentiation. The hydrophobicity and topography of PLGA MS promoted protein adsorption and the stem cells quickly adhered and spread on the surface of these microcarriers. In contrast less proteins adsorbed onto PLGA-P188-PLGA MS and although cells adhered to these microcarriers, they remained round and did not spread on their surface. Despite these earlystage differences, our results suggest that the nature of the MS does not strongly influence the long-term cell behavior. The cells exhibit the same cell number, differentiation profile and ability to secrete ECM molecules regardless of the type of microcarrier used. Likely the ECM molecules that form a microenvironment around both of these 3D microcarrier/cell constructs over time play a role in this converging cell behavior. We have thus furthered our understanding of the physicochemical properties of polymeric cell carriers affecting stem cell behavior to help tailor suitable microcarriers for neuroregenerative applications.

Despite the concern about anthropogenic heavy metal accumulation, there remain few multi-level ecotoxicological studies to evaluate their effects in fluvial ecosystems. The toxicity of field-collected sediments exhibiting a gradient of heavy metal contamination (Cd, Pb, and Zn) was assessed in Chironomus riparius. For this purpose, larvae were exposed throughout their entire life cycle to these sediments, and toxic effects were measured at different levels of biological organization, from the molecular (lipidomic analysis and transcriptional profile) to the whole organism response (respiration rate, shape markers, and emergence rate). Alterations in the activity of relevant genes, as well as an increase of storage lipids and decrease in membrane fluidity, were detected in larvae exposed to the most contaminated sediments. Moreover, reduced larval and adult mass, decrease of larval respiration rate, and delayed emergence were observed, along with increased mentum and mandible size in larvae and decreased wing loading in adults. This study points out the deleterious effects of heavy metal exposure at various levels of biological organization and provides some clues regarding the mode of toxic action. This integrative approach provides new insights into the multi-level effects on aquatic insects exposed to heavy metal mixtures in field sediments, providing useful tools for ecological risk assessment in freshwater ecosystems. © 2019 Elsevier Ltd, The professional editing service NB Revisions was used for technical preparation of the text prior to submission.

Plastic pollution has become one of the most visible environmental issue. Studying the aging and the fragmentation mechanism of polymers therefore raises environmental and health issues. Since it is particularly difficult to monitor all these processes in the real environment, laboratory studies are still necessary to obtain more accurate data and to identify the pathways leading to the outcome of plastic debris in the environment. In this paper we present a new method to prepare micrometer thick LDPE films with different thicknesses and controlled crystalline morphologies (i.e. spherulite size) using dip-coating process. LDPE films presenting different spherulite dimensions were submitted to an accelerated weathering test which indicates that spherulite size has only a weak influence on the rate of photo-oxidation. However, films presenting large spherulites morphologies seem to be more sensitive to surface erosion and crack initiation. We believe that the method developed in this paper can be used to study with more control and more rapidly (i.e. thin film and accelerated weathering) the influence of crystalline morphology on a wide range of semi-crystalline polymers in different ageing conditions and thus help to better understand the fragment production of plastics in the environment.

The surface modification of glycolyzed polyethylene terephthalate (PETg) was performed by surface-initiated ATRP with a statistical copolymer composed of poly(butyl acrylate) (PBuA) and poly(styrenic azobenzene) (PSA). First, a bromo end-capped PETg was previously synthesized and then used to obtain thick films by melting under pressure. The top surface Bromo moieties of the PETg were activated as ATRP macro-intiator to polymerize Butyl Acrylate (BuA) and styrenic azobenzene (SA) monomer. In the meantime, a serial of statistical copolymers was synthetized based on SA and BuA units to finely tuned the glass transition temperature value of copolymer close to the room temperature. The introduction of the BuA unit decreased the initial Tg value of the PSA from 100 to −10 °C. A statistical copolymer P(BuA-stat-SA) with 40 wt% of BuA units with a Tg value around 20 °C was then initiated from the surface of the PETg film to be chemically anchored. Under illumination at 365 nm and 450 nm, a reversible Trans to Cis isomerization of the P(BuA-stat-SA) layer is observed which induces a strong shift of the transmittance of the PET film as a light-triggered UV-protection and wettability. Such materials can be used in the field of flexible substrates for electronic to create light-triggered surfaces properties to tune their adhesion and wettability.

International audience; Beyond the peculiar glass transition temperature (Tg) studied extensively for over two decades, we have investigated in this work the variation of the mass density of polymer thin films, a key property barely put forward in the literature. We were able to directly measure the mass density of polystyrene (PS) and poly (methyl methacrylate) (PMMA) thin films as a function of their thickness from accurate Quartz Crystal Microbalance (QCM) dissolution experiments. Depending on the chemical nature of the polymers, the results showed an unambiguous variation of the mass density when the film thickness was reduced: an increase for PS and a decrease for PMMA films. In the last part, we measured the coefficient of thermal expansion (CTE) of both polymers to rationalize the apparent inconsistency of an increase/decrease in the mass density with the commonly observed depression/rise of the Tg of PS/PMMA films. Surprisingly, the coefficient of thermal expansion and the mass density showed a similar variation with thickness, pointing out a clear correlation between the glass transition temperature, the coefficient of thermal expansion and the free volume of the polymer.

International audience; After more than 2 decades of intense research, the density variation in confined polymer films still remains a puzzling problem subject to controversy as the methods utilized to determine the density are often model dependent. Here, we propose a direct and model independent method to detect the density/refractive index variations in polymer thin films through the adsorption of ceria nanoparticles (NPs) onto their surface. The amount of adsorbed NP scales with the polymer film refractive index; hence, any increase/ decrease in the NP surface coverage directly indicates an increase/decrease in the film refractive index and density. Experimenting our proposed novel approach on two well-studied polymers, we found that the density of polystyrene (PS) thin films deposited on oxide-free Si substrate increases with a reduction of the film thickness. On the contrary, poly(methyl methacrylate) (PMMA) films deposited on wafers with native silicon oxide show a decrease of their density when the film thickness is reduced.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA [ADD1_IRSTEA]Systèmes aquatiques soumis à des pressions multiples; International audience; Toxicokinetic (TK) models are relevant and widely used to predict chemical concentrations in biological organisms. The importance of dietary uptake for aquatic invertebrates has been increasingly assessed in recent years. However, the model parameters are estimated on limited specific laboratory data sets that are bounded by several uncertainties. The aim of this study was to implement a Bayesian framework for simultaneously estimating the parameters of a generic TK model for benthic invertebrate species from all data collected. We illustrate our approach on the bioaccumulation of PCB153 by two species with different life traits and therefore exposure routes: Chironomus riparius larvae exposed to spiked sediment for 7 days and Gammarus fossarum exposed to spiked sediment and/or leaves for 7 days and then transferred to a clean media for 7 more days. The TK models assuming first-order kinetics were fitted to the data using Bayesian inference. The median model predictions and their 95% credibility intervals showed that the model fit the data well. From a methodological point of view, this paper illustrates that simultaneously estimating all model parameters from all available data by Bayesian inference, while considering the correlation between parameters and different types of data, is a real added value for TK modeling. Moreover, we demonstrated the ability of a generic TK model considering uptake and elimination routes as modules to add according to the availability of the data measured. From an ecotoxicological point of view, we show differences in PCB153 bioaccumulation between chironomids and gammarids, explained by the different life traits of these two organisms.

Growth regulator insecticides with juvenoid activity can affect the development and reproduction of non-target organisms such as crustaceans. In this perspective, our previous studies revealed deleterious effects of the juvenoid fenoxycarb at 5 μg L −1 on the embryogenesis and at 50 μg L −1 on the reproductive behavior of the amphipod Gammarus fossarum. In the present study, to determine whether data generated with one amphipod species can be extended to other gammarid species, we tested the effects of a 5 μg L −1 fenoxycarb exposure on three European amphipod species: G. fossarum, Gammarus roeseli, and Echinogammarus longisetosus. We exposed individually 60 freshly fertilized females to fenoxycarb throughout the entire oogenesis/embryogenesis cycle (i.e., 19 days). In newborn individuals from exposed embryos, we measured both pigmentation and lipid reserve impairments while in exposed females, we observed reproductive behavior. At 5 μg L −1 fenoxycarb, reproductive behavior was only altered in G. fossarum. This study demonstrates the variability of the toxic response among the three gammaridae species, underlining the need for acquiring data with a broad phylogenetic representation to better predict toxic effects on freshwater ecosystems. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature., This research was financially supported by the French Ec2co program.

Picosecond laser ultrasonics is an experimental technique for the generation and detection of ultrashort acoustic pulses using ultrafast lasers. In transparent media, it is often referred to as time-domain Brillouin scattering (TDBS). It provides the opportunity to monitor the propagation of nanometers-length acoustic pulses and to determine acoustical, optical, and acousto-optical parameters of the materials. We report on the application of TDBS for evaluating the effect of Praseodymium (Pr) substitution on the elasticity of multiferroic (Bi1&minus, xPrx)(Fe0.95Mn0.05)O3 (BPFMO) thin films. The films were deposited on Si and LaAlO3 (LAO) substrates by a sol-gel method. X-ray diffraction and Raman spectra revealed earlier that a phase transition from rhombohedral to tetragonal structure occurs at about 15% Pr substitution and is accompanied by the maxima of remnant magnetization and polarization. Combining TDBS with optical spectral reflectometry, scanning electron microscopy, and topographic measurements by atomic force microscopy, we found that the structural transition is also characterized by the maximum optical dielectric constant and the minimum longitudinal sound velocity. Our results, together with earlier ones, suggest that BiFeO3-based films and ceramics with compositions near phase boundaries might be promising materials for multifunctional applications.

The media coverage of sport events in relation to athletes’ sex has been extensively analyzed in the scientific literature. Apart from sports mega-events such as the Olympic Games, the findings of these studies seem consistent in that female participants are systematically underrepresented in sports media coverage. However, much of the research in this area relates to North America. Therefore, the aim of this study was to examine sex equity in the coverage of the Sochi 2014 Winter Olympics by French, British and Spanish newspapers to provide new insights in this research field from a different cultural perspective. A content analysis was carried out and mixed results were found. French coverage shows significant discrimination of female athletes on most of the variables analyzed. Conversely, British coverage shows significant discrimination of male athletes on most of the variables studied. Finally, Spanish coverage is fair. These mixed results show the value of conducting such studies in geographical areas outside North America.

International audience; A new telechelic liquid natural rubber is used to elaborate thin coating (

This study examines international newspaper coverage of the 2013 European Basketball Championship for men. Generalist broadsheet newspapers in 13 countries on five continents were examined over the course of 1 year (from August 2012 until September 2013) to understand the amount and content of coverage dedicated to this major event. Results show that the host country, Slovenia, dedicated the most extensive coverage to the EuroBasket, followed by Croatia, a neighboring country. Media interest in other countries was very limited and focused almost exclusively on competitive aspects of the tournament (as opposed to organizational, tourist, or cultural angles). Of the newspapers examined, only five covered the event in the months leading up to it and only four reported the final outcome of the tournament. Generalist broadsheets thus displayed limited interest in the competition, contradicting organizers’ assertions and popular belief of widespread promotional and economic benefits deriving from the event. Newspapers from countries that fielded teams at the event overwhelmingly focused on their performances. As setters of the public agenda, mainstream broadsheets exhibit very limited interest in the myriad major sports events organized worldwide. Hosting such events are not by default the promotional and economic boon organizers argue and the public believes.

The toxicity of three field-collected sediments differentially contaminated with pesticides, heavy metals, phtalates and polycyclic aromatic hydrocarbons (PAHs), was assessed in Chironomus riparius. For this purpose, C. riparius larvae were exposed throughout their entire life cycle to sediments collected in three sites along the Saulx river in France, and the toxic effects were measured at different levels of biological organization: from the molecular (lipidomic analysis and transcriptional variations) to the whole organism response (respiration rate, shape markers and emergence rate). In the sediment characterized by an intermediate level of contamination with PAHs and phtalates, we detected an increase of the cell stress response and delayed emergence of males. In the group exposed to the most contaminated sediment with PAHs, phtalates and pesticides, genes related to endocrine pathways, cell stress response and biotransformation processes were overexpressed, while female wing shape was affected. Field-collected sediment exposure did not induce significant effects on mentum shape markers or on the lipid profile. The present study provides new insights into the multilevel effects of differentially contaminated sediments in insects. This integrative approach will certainly contribute to improved assessment of the risk that complex mixtures of pollutants pose to the aquatic ecosystem. © 2019 Elsevier B.V., The authors acknowledge Bernard Motte for his help and expertise in sediment sampling. Lipidomic analysis was supported by the Spanish Government project CTM2017-83242-R.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA [ADD1_IRSTEA]Systèmes aquatiques soumis à des pressions multiples; International audience; To improve the assessment of aquatic organism responses to environmental stressors, there is an interest in studying epigenetic marks in addition to other validated biomarkers. Indeed, the epigenetic marks may be influenced by the surrounding environment. Non-model invertebrates such as gammarids are sentinel organisms representative of the diversity of natural stream communities. Despite their ecologically relevance, the epigenetic responses have been to date poorly documented in these species. The present study explores the measurement of the global cytosine methylation level in the genome of the freshwater crustacean Gammarus fossarum. In a first step, natural variability of global cytosine methylation level (basal level) was assessed by studying the effect of sex, age and sampling site of organisms. Results showed a significant effect of age and sampling site. In a second step, effects of water temperature and food starvation were studied. For both factors, a hypermethylation was observed after 1 month of exposure. In a third step, gammarids were exposed to a range of environmentally relevant cadmium concentrations (0.05-5 µg/L) in order to assess the effect of a chemical stress. Whatever the cadmium concentration used, a significant hypomethylation was observed after 14 days followed by a trend for hypermethylation after 1 month of exposure. These results are the first ones dealing with the 5Cmethylation status in gammarids. The results constitute potential markers of environmental stresses in relevant sentinel species widely used in ecotoxicological studies.

International audience

International audience; Wastewater treatment plant effluents from urban area are a well-known source of chronic multiple micropollution to the downstream living organisms. In this study, ecologically relevant laboratory-bred freshwater gastropods, Lymnaea stagnalis, were exposed for 29 days to raw effluents of a wastewater treatment plant in Lyon area (France). A time-course analysis of individual markers of immunocompetence (hemocyte density and viability, hemocyte NADPH activity, phenol oxidase activity, and capacity of phagocytosis) has shown slight trends of inflammatory-like responses induced by the 100% effluents. So far, no short-term hazard for L. stagnalis can be revealed. However, over the long term, such environmental stress-stimulating immune responses could provoke deleterious life history trade-offs because the immune system is known to be highly energy-consuming.

Insect growth regulator insecticides mimic the action of hormones on the growth and development of insect pests. However, they can affect the development of non-target arthropods. In the present study, we tested the effects of the growth regulator insecticide fenoxycarb on several endpoints in the freshwater crustacean Gammarus fossarum (Amphipoda). Females carrying embryos in their open brood pouch were exposed to 50 μg L-1 fenoxycarb throughout the entire oogenesis (i.e. 21 days). After exposure, newborn individuals from exposed embryos were removed from the maternal open brood pouch for lipidomic analysis, while males were added to assess the reproductive success. After fertilization, the lipid profile, energy reserve content (lipids, proteins and glycogen), and activity of phenoloxidase − an enzyme involved in the immune response − were measured in females. No significant effect of fenoxycarb exposure was observed on the lipid profile of both newborn individuals and females, while reproductive success was severely impaired in exposed females. Particularly, precopulatory behavior was significantly reduced and fertilized eggs were unviable. This study highlighted the deleterious effects of the insect growth regulator fenoxycarb on gammarid reproduction, which could have severe repercussions on population dynamics. © 2018 Arambourou et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Controlling adsorption of proteins onto medical devices is a key issue for implant-related infections. As self-assembled monolayers (SAMs) on titanium oxide represent a good model to study the surface-protein interactions, TiO 2 surface properties were modified by grafting bisphosphonate molecules terminated with hydrophilic poly(ethylene glycol) groups and hydrophobic perfluoropolyether ones, respectively. Characterisation of the surface chemistry and surface topography of the modified surfaces was performed using XPS and atomic force microscopy (AFM). Quartz-crystal microbalance with dissipation (QCM-D) was used to determine the mass of adsorbed proteins as well as its kinetics. Poly(ethylene glycol)-terminated SAMs were the most effective surfaces to limit the adsorption of both BSA and fibrinogen in comparison to perfluorinated-terminated SAMs and non-modified TiO 2 surfaces, as expected. The adsorption was not reversible in the case of BSA, while a partial reversibility was observed with Fg, most probably due to multilayers of proteins. The grafted surfaces adsorbed about the same quantity of proteins in terms of molecules per surface area, most probably in monolayer or island-like groups of adsorbed proteins. The adsorption on pristine TiO 2 reveals a more important, non-specific adsorption of proteins.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA; International audience; During morphogenesis numerous morphogenetic factors ensure the production of a target phenotype. By disrupting these processes, a toxic exposure during this period could cause an increase of phenotypic defects. In the present study, embryos of the freshwater amphipod Gammarus fossarum were exposed throughout the embryogenesis to increasing concentrations of fenoxycarb (0, 0.5 µg L−1, 5 µg L−1 and 50 µg L−1), a growth regulator insecticide analog of the insect juvenile hormone. In addition, to identify morphogenesis’ sensitive period, embryos were exposed during either early or late embryonic development to 5 µg L−1 of fenoxycarb. In newborn individuals from exposed embryos, three phenotypes were investigated: i) eye pigmentation, ii) length of the antenna and gnathopod of both left and right sides and iii) midgut tissue state. Developmental homeostasis was assessed by measuring fluctuating asymmetry and inter-individual variance of both the antenna and gnathopod. Exposure to 5 µg L−1 and 50 µg L−1 fenoxycarb throughout the embryonic development induced a delayed hatching and altered appendages size. Moreover, exposure to 5 µg L−1 throughout the embryogenesis and during the gastrulation phase impaired eye pigmentation, while exposure to 50 µg L−1 resulted in increased tissue damages of the midgut. No significant increase of fluctuating asymmetry was observed in exposed individuals, neither for the antenna nor for the gnathopod. These results demonstrate that fenoxycarb can alter embryonic development of G. fossarum without disrupting developmental homeostasis.

International audience

International audience; The influence of the sample preparation on the observed dependence of glass transition temperature (T-g) with thickness in polystyrene (PS) thin films has been investigated. Spectroscopic ellipsometry was used to measure the T-g of PS thin films ranging from 7 to 85 nm before and after exposition to supercritical carbon dioxide (sc-CO2). We take advantage of the sc-CO2 properties along with thermal annealing treatment to cancel out sample preparation history factor by removing the remnant solvent and residual stresses. The decrease in T-g shows exactly the same trend before and after sc-CO2 exposure plus thermal treatment. This result cancels out the influence of the spin coating process on the T-g depression in thin films. (C) 2017 Elsevier Ltd. All rights reserved.

Sphingomyelin (SM) molecules are major lipid components of plasma membranes that are involved in functional domains. Among natural SMs, that found in milk (milk-SM) exhibits important acyl chain heterogeneities in terms of length and saturation, which could affect the biophysical properties and biological functions of the milk fat globule membrane or of liposome carriers. In this study, the thermotropic and mechanical properties of milk-SM, synthetic C16:0-SM, C24:0-SM and the binary mixtures C16:0-SM/C24:0-SM (50:50% mol) and C24:0-SM/C24:1-SM (95:5% mol) bilayer membranes were investigated using differential scanning calorimetry and atomic force microscopy, respectively. Results showed that acyl chain length, heterogeneity and unsaturation affected i) the temperature of phase transition of SM bilayers, and ii) the mechanical properties of liposome (diameter

International audience; In many liposome applications, the nanomechanical properties of the membrane envelope are essential to ensure, e.g., physical stability, protection, or penetration into tissues. Of all factors, the lipid composition and its phase behavior are susceptible to tune the mechanical properties of membranes. To investigate this, small unilamellar vesicles (SUV; diameter < 200 nm), referred to as liposomes, were produced using either unsaturated 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or saturated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) in aqueous buffer at pH 6.7. The respective melting temperatures of these phospholipids were −20 and 41 °C. X-ray diffraction analysis confirmed that at 20 °C DOPC was in the fluid phase and DPPC was in the gel phase. After adsorption of the liposomes onto flat silicon substrates, atomic force microscopy (AFM) was used to image and probe the mechanical properties of the liposome membrane. The resulting force–distance curves were treated using an analytical model based on the shell theory to yield the Young’s modulus (E) and the bending rigidity (kC) of the curved membranes. The mechanical investigation showed that DPPC membranes were much stiffer (E = 116 ± 45 MPa) than those of DOPC (E = 13 ± 9 MPa) at 20 °C. The study demonstrates that the employed methodology allows discrimination of the respective properties of gel- or fluid-phase membranes when in the shape of liposomes. It opens perspectives to map the mechanical properties of liposomes containing both fluid and gel phases or of biological systems.

The French private sport sector has resisted the 2008 economic crisis particularly well and it has been seen as an important lever for the French economy growth. Consequently, the development and the structuration of this sector has become a strategic priority for the French Government. The private sport sector has generated a total revenue of 16.7 billion euros in 2013. With 8.6 billion euros of revenue, the retail sale of sport equipment and bicycles represents 51.5% of the total revenue in the French private sport sector. This performance really sets it apart from the other significant business fields. Additionally, this business field is the most important in terms of employment. It is also one of the most efficient and one of the biggest in relation to the number of companies. It is thus an important business field for the sport economy and more broadly for the French economy. For all these reasons, after the presentation of the main characteristics of (1) the organisation of sport in France and of (2) the private sport sector, this chapter will specifically focus on (3) the French sport goods retailers and their links with the sport goods manufacturers.

Effects observed within one generation disregard potential detrimental effects that may appear across generations. Previously we have developed a two generation Daphnia magna reproduction test using the OECD TG 211 protocol with a few amendments, including initiating the second generation with third brood neonates produced from first generation individuals. Here we showed the results of an inter-laboratory calibration exercise among 12 partners that aimed to test the robustness and consistency of a two generation Daphnia magna reproduction test. Pyperonyl butoxide (PBO) was used as a test compound. Following experiments, PBO residues were determined by TQD-LC/MS/MS. Chemical analysis denoted minor deviations of measured PBO concentrations in freshly prepared and old test solutions and between real and nominal concentrations in all labs. Other test conditions (water, food, D. magna clone, type of test vessel) varied across partners as allowed in the OECD test guidelines. Cumulative fecundity and intrinsic population growth rates (r) were used to estimate “No observed effect concentrations “NOEC using the solvent control as the control treatment. EC10 and EC-50 values were obtained regression analyses. Eleven of the twelve labs succeeded in meeting the OECD criteria of producing > 60 offspring per female in control treatments during 21 days in each of the two consecutive generations. Analysis of variance partitioning of cumulative fecundity indicated a relatively good performance of most labs with most of the variance accounted for by PBO (56.4%) and PBO by interlaboratory interactions (20.2%), with multigenerational effects within and across PBO concentrations explaining about 6% of the variance. EC50 values for reproduction and population growth rates were on average 16.6 and 20.8% lower among second generation individuals, respectively. In summary these results suggest that the proposed assay is reproducible but cumulative toxicity in the second generation cannot reliably be detected with this assay.

© 2014 by Pleiades Publishing, Ltd. In this work we assessed the performance of the density functional theory (DFT) approach through a comparison study with the experimental Raman spectrum obtained for [4-[( E)-phenylazo]phenyl]ethanol (ABOH) in the wave number range 900-1800 cm-1. The assignment of the ten most active vibrational modes is achieved using the hybrid B3LYP method with the 6-311++G(2d,2p) basis set. Two molecules of reference [N-ethyl-4-[( E)-(4-nitrophenyl)azo]anilino]ethanol (Disperse Red 1, DR1) and 4-[( E)-(4-nitrophenyl) azo]aniline (Disperse Orange 3, DO3) are also investigated in order to consider this method in the calculation of the Raman intensities. The experimental Raman spectrum of DR1 is compared with those of the three stable configurations obtained at the B3LYP/6-311++G(2 d,2p) level.

X-ray reflectivity, atomic force microscopy, X-ray photoelectron spectroscopy, and contact angle measurement techniques are used to study the structural changeover as a function of concentration of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer diluted in toluene spin-coated as ultrathin films on hydrophilic Si substrate. A lamellar structure made of three alternating incomplete bilayers is observed until the concentration of copolymer solution attains a threshold value of about 3.6-4 g/L. Around this concentration and beyond, the entanglement of polymer chains takes place during drying and the growth of a homogeneous film made of complete bilayers on Si substrate is observed. The strong hydrophilic nature of the Si substrate dictates the growth of this amphiphilic copolymer. We evidence that the lower part of the films is made of hydrophilic PEO blocks attached to the substrate while the hydrophobic PPO blocks are directed toward air.

In previous literature, there is an important heterogeneity in how to proceed to determine whether media coverage of the Summer Olympics in relation to athletes' sex is equitable. Therefore, the aims of this study are to determine the most appropriate standards for this comparison and to use them to assess whether there are biases in the journalistic coverage of the Summer Games, using data from previous studies (n = 18). Results show that media coverage is far from being detrimental to women: They are either equitably represented (28.79%) or significantly overrepresented (46.97%). Indeed, all modalities combined, women are only underrepresented in 22.24% of cases. In most cases, these results significantly differ from those of previous research and stress the importance of and the need to take methodological precautions in this type of study.

In this work, the artificial photodegradation of polyethylene films was studied in laboratory to compare the fragmentation pathways of this polymer at air and in water. Oxidation, surface mechanical properties, crystallinity and crack propagation were monitored to investigate their influence on fragmentation. Without any external stress, fragmentation only occurred in water despite a higher level of oxidation for films weathered at air. The cracking of the films did not appear correlated with the oxidation level and the presence of water appeared as a promoter of cracking propagation. The results also showed that the mechanical properties at the surface play a major role in the fragmentation pathway whereas the fabrication process may influence the propagation direction of the cracks. Consequently, the distribution in size of plastic fragments in the aquatic environment may be linked to the nature of the polymer but also to its manufacturing process. In this study, after 25 weeks of weathering in water, 90% of the fragments were1 mm with very similar shapes showing that micrometric fragments were not yet abundant. These results suggest that long times of weathering in water and many steps of fragmentation appear necessary from macroplastics to reach sizes1 mm in the aquatic environment. These results constitute a first attempt to understand the pathways leading from macroplastics to microplastics in water. They have to be confirmed for other polymers and the long-term behavior of the fragments needs to be studied to predict their decrease in size among time.

Previous research suggested that the relative age effect (RAE) has a psychological influence on children and their decision to engage in a particular sport. Relatively younger children seem to have lower self-esteem. Indeed, because of the disadvantages of being younger, it is assumed that these players experience more situations of failure and inferiority. Because of these negative performance cues, it is likely that these young players feel less competent, which eventually leads to a higher dropout rate. These children can also decide to participate in sports in which physical attributes are less important. This shift from one sport to another can be interpreted as a 'strategic adaptation'. The purpose of this study was thus to investigate whether refereeing could be another form of 'strategic adaptation'. If a child chooses a specific sport but then does not feel competent enough to be a player, refereeing might be an alternate path followed to stay in the environment of a sport they like. Given the minimal age limits for refereeing, two hypotheses were formulated: (1) 'reversed' RAE would be observed in district referees younger than 18 years old and (2) no RAE would be observed in district referees older than 18 years old, regional referees and national referees. The birthdates of all official male soccer referees (n=13,952) were collected from the federation database. Results show that the distribution of all district referees was significantly unbalanced (χ(2)=18.73, df=3, P

This paper analyzes the bias sources of mechanical and electrostatic origin in a tuning fork microelectromechanical systems (MEMS) gyroscope. In a gyroscope which is symmetrical and has no defect, there would be no bias; technological defects should be investigated in order to identify and quantify bias sources, which arise from quadrature and in-phase errors. Technological dispersions within the etching step of the mechanical structure are a major source of errors. Dispersions at the scale of a single MEMS particularly matter by impacting springs and electrodes. Design rules are defined for a z-axis gyroscope in order to curb these errors: In particular, specific drive springs, which are very stiff in the sense direction, and a mechanical decoupling between drive and sense are indicated to decrease errors. Local dispersion of the width of beams has been assessed with a network of electrical test structures and leads to a local standard deviation of 3-6 nm at the scale of a MEMS gyroscope device. The optimized design enables to obtain a total error of less than 300°/s on very compact z-axis gyroscopes with an area of mechanical part of 0.5 mm2.