Search

Core–shell structure hybrids of carbon nanotubes (CNTs)/BaTiO3 (H-CNT-BT) and commercial multi-wall CNTs are respectively incorporated into poly(vinylidene fluoride) (PVDF) for preparing the composites near the percolation thresholds. A comprehensive investigation for CNT's dispersion and composite's conductivity is conducted between H-CNT-BT/PVDF and CNT/PVDF at different depths vertical to the injection's direction. Gradual increases of the conductivity in two composites are observed from the out-layer to the core part which infers an inhomogeneous CNT's dispersion in the interior of composites due to their migration under flow during the injection. However, the use of H-CNT-BT fillers with core–shell structure enables to reduce this inhomogeneous dispersion in the composite. Furthermore, the conductive network of CNTs in H-CNT-BT/PVDF is less sensitive to the thermal treatment than the one in CNT/PVDF composite, which infers the core–shell structure of hybrids can ameliorate the sensitivity of the conductive network. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45693.

International audience; Silicon (Si) is the second most abundant element in the Earth's crust and is an important nutrient in the ocean. The global Si cycle plays a critical role in regulating primary productivity and carbon cycling on the continents and in the oceans. Development of the analytical tools used to study the sources, sinks, and fluxes of the global Si cycle (e.g., elemental and stable isotope ratio data for Ge, Si, Zn, etc.) have recently led to major advances in our understanding of the mechanisms and processes that constrain the cycling of Si in the modern environment and in the past. Here, we provide background on the geochemical tools that are available for studying the Si cycle and highlight our current understanding of the marine, freshwater and terrestrial systems. We place emphasis on the geochemistry (e.g., Al/Si, Ge/Si, Zn/Si, delta C-13, delta N-15, delta O-18, delta Si-30) of dissolved and biogenic Si, present case studies, such as the Silicic Acid Leakage Hypothesis, and discuss challenges associated with the development of these environmental proxies for the global Si cycle. We also discuss how each system within the global Si cycle might change over time (i.e., sources, sinks, and processes) and the potential technical and conceptual limitations that need to be considered for future studies.

WBE has now become a complimentary tool in SARS-CoV-2 surveillance. This was preceded by the established application of WBE to assess the consumption of illicit drugs in communities. It is now timely to build on this and take the opportunity to expand WBE to enable comprehensive assessment of community exposure to chemical stressors and their mixtures. The goal of WBE is to quantify community exposure, discover exposure-outcome associations, and trigger policy, technological or societal intervention strategies with the overarching aim of exposure prevention and public health promotion. To achieve WBE's full potential, the following key aspects require further action: (1) Integration of WBE-HBM (human biomonitoring) initiatives that provide compre-hensive community-individual multichemical exposure assessment. (2) Global WBE monitoring campaigns to provide much needed data on exposure in low-and middle-income countries (LMICs) and fill in the gaps in knowledge especially in the underrepresented highly urbanised as well as rural settings in LMICs. (3) Combining WBE with One Health actions to enable effective interventions. (4) Advancements in new analytical tools and methodologies for WBE progression to enable biomarker selection for exposure studies, and to provide sensitive and selective multiresidue analysis for trace multi-biomarker quantification in a complex wastewater matrix. Most of all, further developments of WBE needs to be undertaken by co-design with key stakeholder groups: government organisations, health authorities and private sector.

This study describes a simple and low-cost method for fabricating novel 2–3-type composites composed of zinc flakes and polyvinylidene fluoride (PVDF) by direct wet ball-milling and hot-pressing of the mixture of raw zinc powders and PVDF powders in alcohol. It is interesting that zinc spherical powders can be changed into 2-dimensional zinc flakes in the ball-milling and parallel oriented in the polymer under the following hot-pressing process. The composites are demonstrated to have significantly higher dielectric constants than those of bulk zinc/PVDF composites, with quite low dielectric loss and good thermal stability. A mechanism of parallel-board microcapacitor is proposed to explain the relationship of microstructure and dielectric properties.

International audience; Determination of distribution and chemical speciation of arsenic and heavy metals in five acidic springs and in the receiving river near Srebrenica (Bosnia and Herzegovina) was carried out. These waters were used for centuries, and continue to be used, for health-care purposes. The composition and properties of all springs and the river water (after all inputs) resembled that of an acid mine drainage. Very low pH (< 3.3), high sulphate concentration and extremely high contents of most of the measured elements (25) are found in all springs (e.g. arsenic and iron maximal concentration of 6.6 and 500 mg L− 1, respectively). Although of small discharge, spring waters caused the decrease of the receiving river pH (from 7.3 to 3.4) and the considerable increase of the concentrations of elements. The enrichment factor for the studied elements ranged from 1.2 for Sr up to 425 for As. In acidic spring waters, all elements were predominantly present in dissolved form. Elements associated to freshly-formed hydrous ferric oxide were prevailing in particulate forms only at the two most upstream sites in the river with pH > 7. Geochemical speciation modelling (PHREEQC and WHAM-VI) revealed that As was mainly present as As(V), and Fe as Fe(III). Complexation of dissolved metals by organic matter was predicted to be significant only for the two river sites with neutral pH.

International audience; Orderly polymer composites based on polyvinylidene fluoride assembled with parallel aligned zinc flakes were fabricated by a simple process. It is interesting to note that the microstructure of parallel arrangement could introduce excellent dielectric properties with obvious anisotropic dielectric behaviors. The dielectric constant in the parallel direction was obviously higher than that of the perpendicular direction. And the anisotropic intensity of interfacial polarization is proposed to interpret the anisotropic dielectric constant. Also, an equivalent circuit model of two parallel RC circuits in series, based on the analysis of impedance data, is employed to further discuss the anisotropic dielectric behavior.

Polyvinylidene fluoride (PVDF) composites filled by self-passivated zinc (Zn) particles were fabricated through a simple method of flocculation. The following measurement exhibits that the Zn/PVDF composite with filler volume fraction of 0.24 possesses the excellent dielectric properties, and the obtained dielectric constant and loss at 10 3 Hz were 52 and 0.05, respectively. It's considered that high dielectric constant is originated from the enhanced interfacial polarization, while the low loss is due mainly to the self-passivation layer of zinc carbonate hydroxide, which can serve as the insulating interface and reduce leakage current effectively through blocking the free transfer of charge carriers between adjacent Zn fillers. The developed polymer composites with favorable dielectric properties are potential for embedded capacitor applications.

Four crystalline lanthanide(III) three-dimensional (3D) coordination polymers {[La(BDOA) 1.5 (H 2 O)] · H 2 O} n ( 1 ), {[Nd(BDOA) 1.5 (H 2 O)] · H 2 O} n ( 2 ), [Tm(BDOA) 1.5 (H 2 O)] n ( 3 ), [Yb(BDOA) 1.5 (H 2 O)] n ( 4 ) were obtained under hydrothermal conditions and characterized by elemental analysis, IR, as well as single-crystal X-ray diffraction. Compounds 1 and 2 crystallize in the monoclinic system, space group P 2 1 / c , they are isostructural and exhibit the same 3 21 .4 57 .5 13 topological network constructed from different coordination modes of two BDOA ligands, whereas isostructural 3 and 4 crystallizes in the triclinic system, space group P 1 ¯ , it holds 3 9 .4 20 .5 7 topological architecture based on another two different coordination modes BDOA ligands. Moreover, a computational method is applied to evaluate the potential porosity of complex 1 .

With inherent biocompatibility, biodegradability, and unique programmability, hydrogels with a DNA framework show great potential in three-dimensional (3D) cell culture. Here, a DNA hydrogel was assembled by a dendritic DNA with four branches. The hydrogel showed tunable mechanical strength and reversible thixotropy even under a nanomolar DNA concentration. The cell culture medium can be converted into the hydrogel isothermally at physiological temperature. This DNA hydrogel allows both cancer and somatic cells to be seeded in situ and to achieve high proliferation and viability. The bis-entity of dendritic branches enabled the specific loading of bioactive clues to regulate cell behaviors. Thus, the dendritic DNA-assembled hydrogel could serve as a highly biocompatible, readily functionalizing, and easy-casting gel platform for 3D cell culture. This work is supported by the Zhejiang University (start-up grant) and the National Natural Science Foundation of China (21975217) to F.S.

In the brackish water Baltic Sea, oil pollution is an ever-present and significant environmental threat mainly due to the continuously increasing volume of oil transport in the area. In this study, effects of exposure to crude oil on two common Baltic Sea species, the mussel Mytilus trossulus and the amphipod Gammarus oceanicus, were investigated. The species were exposed for various time periods (M. trossulus 4, 7, and 14 days, G. oceanicus 4 and 11 days) to three oil concentrations (0.003, 0.04, and 0.30 mg L−1 based on water measurements, nominally aimed at 0.015, 0.120, and 0.750 mg L−1) obtained by mechanical dispersion (oil droplets). Biological effects of oil exposure were examined using a battery of biomarkers consisting of enzymes of the antioxidant defense system (ADS), lipid peroxidation, phase II detoxification (glutathione S-transferase), neurotoxicity (acetylcholinesterase inhibition), and geno- and cytotoxicity (micronuclei and other nuclear deformities). In mussels, the results on biomarker responses were examined in connection with data on the tissue accumulation of polycyclic aromatic hydrocarbons (PAH). In M. trossulus, during the first 4 days of exposure the accumulation of all PAHs in the two highest exposure concentrations was high and was thereafter reduced significantly. Significant increase in ADS responses was observed in M. trossulus at 4 and 7 days of exposure. At day 14, significantly elevated levels of geno- and cytotoxicity were detected in mussels. In G. oceanicus, the ADS responses followed a similar pattern to those recorded in M. trossulus at day 4; however, in G. oceanicus, the elevated ADS response was still maintained at day 11. Conclusively, the results obtained show marked biomarker responses in both study species under conceivable, environmentally realistic oil-in-seawater concentrations during an oil spill, and in mussels, they are related to the observed tissue accumulation of oil-derived compounds.

Carbonyl sulfide (COS), a trace gas showing striking similarity to CO2 in terms of biochemical diffusion pathway into leaves, has been recognized as a promising indicator of the plant gross primary production (GPP), the amount of carbon dioxide that is absorbed through photosynthesis by terrestrial ecosystems. However, large uncertainties about the other components of its atmospheric budget prevent us from directly relating the atmospheric COS measurements to GPP. The largest uncertainty comes from the closure of its atmospheric budget, with a source component missing. Here, we explore the benefit of assimilating both COS and CO2 measurements into the LMDz atmospheric transport model to obtain consistent information on GPP, plant respiration and COS budget. To this end, we develop an analytical inverse system that optimizes biospheric fluxes for the 15 plant functional types (PFTs) defined in the ORCHIDEE global land surface model. Plant uptake of COS is parameterized as a linear function of GPP and of the leaf relative uptake (LRU), which is the ratio of COS to CO2 deposition velocities in plants. A possible scenario for the period 2008–2019 leads to a global biospheric sink of 800 GgS yr−1, with higher absorption in the high latitudes and higher oceanic emissions between 400 and 600 GgS yr−1 most of which is located in the tropics. As for the CO2 budget, the inverse system increases GPP in the high latitudes by a few GtC yr−1 without modifying the respiration compared to the ORCHIDEE fluxes used as a prior. In contrast, in the tropics the system tends to weaken both respiration and GPP. The optimized components of the COS and CO2 budgets have been evaluated against independent measurements over North America, the Pacific Ocean, at three sites in Japan and at one site in France. Overall, the posterior COS concentrations are in better agreement with the COS retrievals at 250 hPa from the MIPAS satellite and with airborne measurements made over North America and the Pacific Ocean. The system seems to have rightly corrected the underestimated GPP over the high latitudes. However, the change in seasonality of GPP in the tropics disagrees with solar-induced fluorescence (SIF) data. The decline in biospheric sink in the Amazon driven by the inversion also disagrees with MIPAS COS retrievals at 250 hPa, highlighting the lack of observational constraints in this region. Moreover, the comparison with the surface measurements in Japan and France suggests misplaced sources in the prior anthropogenic inventory, emphasizing the need for an improved inventory to better partition oceanic and continental sources in Asia and Europe.

The ocean contains a large reservoir of dissolved organic matter (DOM) that persists for millennia. Both the very dilute concentrations of individual DOM molecules and intrinsic recalcitrance to microbial decay imparted by molecular structure are suggested mechanisms for this long residence time. Here, we report an experiment comparing the responses of surface and deep prokaryotes to DOM isolated and enriched by solid‐phase extraction from surface and deep waters of the subtropical North Atlantic Ocean. Extracts from both depths were qualitatively characterized as biologically recalcitrant given their similarly high C : N ratios of 26. Surface prokaryotes measurably drew down extracted dissolved organic carbon (DOC) concentrations, but the drawdown was only 4% of the initial enriched DOC concentration regardless of enrichment level or depth. Deep microbes, in contrast, did not cause observable changes in DOC concentrations. Surface and deep prokaryotes had similar temperature‐normalized growth responses to extracts from each depth. Biological indicators (e.g., kinetics) suggest that prokaryotes were less efficient at catalyzing surface than deep DOM (catalytic efficiencies of 0.003–0.005 vs. 0.02–0.03 h−1, respectively). These values indicate qualitative differences in extracted DOM from the two depths, perhaps suggesting a variable nature of the refractory DOC depending on depth. Moreover, only a small portion of the extracted DOM was biologically utilizable, regardless of concentration factor or depth, and essentially only a small fraction of it was incorporated into biomass. Microbial selection against substrates that meet modest energy but no growth demands may be a factor contributing to the long‐term stability of marine DOM.

21 pages, 4 figures, 3 tables.-- This work is distributed under the Creative Commons Attribution 4.0 License, The element silicon (Si) is required for the growth of silicified organisms in marine environments, such as diatoms. These organisms consume vast amounts of Si together with N, P, and C, connecting the biogeochemical cycles of these elements. Thus, understanding the Si cycle in the ocean is critical for understanding wider issues such as carbon sequestration by the ocean’s biological pump. In this review, we show that recent advances in process studies indicate that total Si inputs and outputs, to and from the world ocean, are 57% and 37% higher, respectively, than previous estimates. We also update the total ocean silicic acid inventory value, which is about 24% higher than previously estimated. These changes are significant, modifying factors such as the geochemical residence time of Si, which is now about 8000 years, 2 times faster than previously assumed. In addition, we present an updated value of the global annual pelagic biogenic silica production (255 Tmol Si yr-1) based on new data from 49 field studies and 18 model outputs, and we provide a first estimate of the global annual benthic biogenic silica production due to sponges (6 Tmol Si yr-1). Given these important modifications, we hypothesize that the modern ocean Si cycle is at approximately steady state with inputs D 14:8(+-2:6) Tmol Si yr-1 and outputs D 15:6(+-2:4) Tmol Si yr-1. Potential impacts of global change on the marine Si cycle are discussed, This work was supported by the French National Research Agency (18-CEO1-0011-01) and by the Spanish Ministry of Science, Innovation and Universities (PID2019-108627RB-I00)

Despite the large number of polymeric nanodelivery systems that have been recently developed, there is still room for improvement in terms of therapeutic efficiency. Most reported nanodevices for controlled release are based on drug encapsulation, which can lead to undesired drug leakage with a consequent reduction in efficacy and an increase in systemic toxicity. Herein, we present a strategy for covalent drug conjugation to the nanodevice to overcome this drawback. In particular, we characterize and evaluate an effective therapeutic polymeric PEGylated nanosystem for controlled pH-sensitive drug release on a breast cancer (MDA-MB-231) and two lung cancer (A549 and H520) cell lines. A significant reduction in the required drug dose to reach its half maximal inhibitory concentration (IC50 value) was achieved by conjugation of the drug to the nanoparticles, which leads to an improvement in the therapeutic index by increasing the efficiency. The genotoxic effect of this nanodevice in cancer cells was confirmed by nucleus histone H2AX specific immunostaining. In summary, we successfully characterized and validated a pH responsive therapeutic polymeric nanodevice in vitro for controlled anticancer drug release., Spanish Ministry of Economy and Competitiveness (MINECO) BIO2016-80519, Health Institute Carlos III (ISCIII) DTS18/00121, Andalusian Regional Government PAIDI-TC-PVT-PSETC-2.0

In spite of the enormous potential of CRISPR/Cas in basic and applied science, the levels of undesired genomic modifications cells still remain mostly unknown and controversial. Nowadays, the efficiency and specificity of the cuts generated by CRISPR/Cas is the main concern. However, there are also other potential drawbacks when DNA donors are used for gene repair or gene knock-ins. These GE strategies should take into account not only the specificity of the nucleases, but also the fidelity of the DNA donor to carry out their function. The current methods to quantify the fidelity of DNA donor are costly and lack sensitivity to detect illegitimate DNA donor integrations. In this work, we have engineered two reporter cell lines (K562_SEWAS84 and K562GWP) that efficiently quantify both the on-target and the illegitimate DNA donor integrations in a WAS-locus targeting setting. K562_SEWAS84 cells allow the detection of both HDR-and HITI-based donor integration, while K562GWP cells only report HDR-based GE. To the best of our knowledge, these are the first reporter systems that allow the use of gRNAs targeting a relevant locus to measure efficacy and specificity of DNA donor-based GE strategies. By using these models, we have found that the specificity of HDR is independent of the delivery method and that the insertion of the target sequence into the DNA donor enhances efficiency but do not affect specificity. Finally, we have also shown that the higher the number of the target sites is, the higher the specificity and efficacy of GE will be., Spanish ISCIII Health Research Fund, European Union (EU) PI15/02015 PI18/00337 PI18/00330, CECEyU of the Junta de Andalucia FEDER/European Cohesion Fund (FSE) 2016000073391-TRA 2016000073332-TRA PI-57069 CARTPI-0001-201 PAIDI-Bio326 PI-0014-2016, CSyF of the Junta de Andalucia FEDER/European Cohesion Fund (FSE) 2016000073391-TRA 2016000073332-TRA PI-57069 CARTPI-0001-201 PAIDI-Bio326 PI-0014-2016, Nicolas Monardes regional Ministry of Health contract 0006/2018, Fundacion Poco Frecuente, Spanish Government FPU17/04327 FPU17/02268, ISCIII through a PFIS fellowship FI19/00163, SMSI PEJ-2018-001760-A

We analyzed for the first time the metabolic profile of Lebanese children affected by autistic disorders to compare this profile to other metabolomics studies and to identify the associated metabolic disturbances. Urine samples of 40 patients with Autism spectrum disorder (ASD) and 40 healthy matched controls were analyzed using nuclear magnetic resonance (NMR) and liquid chromatography coupled to high-resolution mass spectrometry (LC-MS). Multivariate analysis on analytical data fusion was conducted on the training set of 50 urine samples, and then validated with a test set of 30 samples, this repeated 10 times. The model was also evaluated using a receiver operating characteristic curve showing a specificity and a sensitivity of 86% and 80%, respectively. Among the most significant metabolites that contributed to the discrimination between ASD and controls, we confirmed the perturbations of tyrosine, 2-hydroxybutyrate, creatine and glutamate. We found new metabolites such as trigonelline, cysteic acid and guanine. We found metabolic perturbations including amino acids, carbohydrates and oxidative stress pathways which added value for the contribution of known metabolic disturbances in ASD observed in populations of other ethnic and geographic origins.

8 pages, Extremely low concentrations of platinum in natural waters require very sensitive analytical techniques, with adsorptive cathodic stripping voltammetry (AdCSV) being one of the most frequently used techniques. A ‘fine tuning’ of the voltammetric parameters, along with advanced data treatment based on derivative transformations, allowed us to determine reliably Pt levels down to 50 fM (0.05 pM). By using short modulation and interval times of the differential pulse stripping waveform, and applying a 4th derivative transformation to the voltammograms, the limit of detection (LOD) was lowered down to 10 fM. Although very small concentrations of surface-active substances (e.g. 0.025 mg L−1 fulvic acid) strongly influenced the method sensitivity, recoveries of spiked samples were not impacted (~100 %). The application of a desorption step (Eds = −1.35 V; tds = 2 s) at the end of the accumulation significantly improved the sensitivity, presumably through the removal of adsorbed surface-active substances. Using this optimised methodology, we determined the Pt distribution in the pristine Krka River estuary in the winter and summer periods by performing both horizontal transects and vertical profiles (salinity ~1 to 39). In surface waters, dissolved Pt concentrations gradually increased towards the seawater end-member (from ~0.15 to ~0.3 pM). A small deviation from the conservative mixing line was observed at salinities below 10, which may reflect changes in Pt redox speciation. In bottom waters, the trend was opposite with dissolved Pt concentrations increasing towards the freshwater end-member, probably owing to progressive accumulation related to seawater residence time. On average, 90 % of Pt was present in the dissolved form

Contaminated sediments could act as a source of contamination to the surrounding environments by several processes (e.g., diffusive flux, sediment resuspension). This study aimed at highlighting the mechanisms of copper and lead mobilization from resuspended particles to the aqueous phase using laboratory experiments and a kinetic model. Three sediments, differed by their compositions and metal partition from Toulon Bay (SE France) were used. In addition, three solid/liquid ratios (0.1, 1 and 10 g L−1) allowed simulating at best natural and anthropogenic scenarios (e.g., storm, nautical traffic, dredging). We monitored metal concentrations, physicochemical parameters (pH, Eh, [O2]) and organic matter concentration along with their optical properties. Experimental results showed successive reactions over short and long terms (hour and day scale, respectively) that controlled Cu and Pb exchanges between particles and the aqueous phase over 4 weeks. The quick Cu removal was attributed to the implications of newly formed oxides while the long-term Cu release in the dissolved fraction from the more refractory solid pool is more likely related to organic complexation. In fact, we observed a transformation of the dissolved organic matter: an increase in molecular weight and in humic fluorescence properties. However, the Pb removal toward the end of the experiment could be explained by a migration toward the exchangeable sites of higher energy, which could correspond to the particulate organic matter or a combination with organic-coating carrier phases. Both kinetic rate and system response times (τi) were coherent despite the variability of parameters intrinsic to sediments (e.g., sediment composition and initial metal repartition) but also extrinsic parameters (solid/liquid ratios). Such a coherence would imply the universality of the obtained constants to be used in a more predictive approach to assess the potential of metal mobility using metal repartition in contaminated sediments when combined with hydrological and sedimentological models.

International audience; Chromium is a toxic element naturally present in natural waters whose chemical speciation regulates its cycling, mobility and bioavailability. We present here: 1-an improved analytical 16 method for chromium speciation (Cr(VI) vs Cr(III)) in estuarine samples by catalytic adsorptive cathodic stripping voltammetric (cat-AdCSV) and 2-a study highlighting a significant change of redox speciation during summer and winter. Initial measurements first revealed that surface-active substances (SAS) present in estuarine samples strongly influenced the analytical determination of Cr by partially masking the Cr peak through an increase of the background current. We found that the application of a low negative accumulation potential (- 1.65 V) resulted in much better voltammograms compared to those obtained using the usual accumulation potential of-1.0 V. Using humic acid (HA) as a model SAS of natural origin, we show that this negative potential clearly prevents adsorption of SAS on the Hg-electrode surface, which in turns benefits the adsorption of the in-situ formed Cr(III)-DTPA complex and the resulting signal. The optimised method was applied to determine chromium redox speciation and distribution along the 23 km long salinity gradient, well oxygenated, Krka River estuary (Croatia). Cr(VI) was found to be the dominant redox species in both summer and winter, with Cr(III) contribution being lower in summer (up to ~30%, average of ~5%) than in winter (up to ~50%, average of ~30%). In summer, lower concentrations of Cr(VI) were found in the freshwater end-member (2.5 nM) than in the seawater end-member (4-5 nM), while the opposite trend was found in winter. Hexavalent chromium exhibited a non-conservative behaviour along the salinity gradient for both seasons. Chromium predominantlyexists in dissolved phase, and contribution of particles reactive Cr(III) was minor.

Nutrient availability and temperature are important drivers of phytoplankton growth and stoichiometry. However, the interactive effects of nutrients and temperature on phytoplankton have been analyzed mostly by addressing changes in average temperature, whereas recent evidence suggests an important role of temperature fluctuations. In a laboratory experiment, we grew a natural phytoplankton community under fluctuating and constant temperature regimes across 25 combinations of nitrogen (N) and phosphorus (P) supply. Temperature fluctuations decreased phytoplankton growth rate (r(max)), as predicted by nonlinear averaging along the temperature-growth relationship. r(max) increased with increasing P supply, and a significant temperature x P x N interaction reflected that the shape of the thermal reaction norm depended on nutrients. By contrast, phytoplankton carrying capacity increased with N supply and in fluctuating rather than constant temperature. Higher phytoplankton N:P ratios under constant temperature showed that temperature regimes affected cellular nutrient incorporation. Minor differences in species diversity and composition existed. Our results suggest that temperature variability interacts with nutrient supply to affect phytoplankton physiology and stoichiometry at the community level.

A series of Ce/TiOx-functionalized catalytic ceramic membranes (CeTi-CeCCMs) were fabricated via citrate sol-gel assisted wet impregnation followed by acid-hydrolysed sol-gel dip coating method. The effect of Ce-dopant and block-copolymer P-123 on the formation of Ce-doped TiOx was investigated and optimized to fabricate a uniform Ce-doped TiOx layer with hierarchical porous structure. The modifications adopted for the CCM fabrication had a marginal effect on the clean water permeability, which is favourable towards the membrane filtration process. Meanwhile, the nanocatalysts located at the membrane outer surface and within the membrane substrate of CCM could significantly enhance the accessibility of the reactants to the catalytic sites. The as-fabricated CCMs were employed for N,N-diethyl-m-toluamide (DEET) degradation in the hybrid catalytic ozonation-membrane filtration process operating under continuous dead-end filtration mode. CeTi-CeCCM recorded a high DEET degradation and mineralization with efficient O3(aq) utilization of 1.4 g O3(aq) g−1 TOC removal. The CeTi-CeCCM also exhibited a high antifouling property in the hybrid process by retaining >92% of its initial permeability after 0.5-h operation with humic acid feed. The stability and robustness of the as-fabricated CCM were also tested with multiple filtration-cleaning cycles and using real water feed, respectively. The reactive oxygen species (ROS) quenching and radical detection experiments were conducted to determine the contribution of ROS (i.e. HO[rad], O2[rad]− and 1O2) towards the catalytic activity. The degradation pathways of DEET were proposed and the ecotoxicity of its transformation products (TPs) was estimated. Finally, the mechanistic insights of the O3(aq) decomposition, organic pollutants degradation and mineralization by the CeTi-CeCCM were provided to address the synergistic effect of the membrane filtration and catalytic ozonation occurred in the hybrid process. Ministry of Education (MOE) Nanyang Technological University This work was supported by the Ministry of Education (MOE), Singapore [RG96/16 Academic Research Grant]. W.J. Lee would like to thank Nanyang Technological University, Singapore for his PhD research scholarship.

International audience; A new silver cobalt diphosphate, Ag3.68Co2(P2O7)2, is synthesized by solid-state reaction route. Crystal structure and Ag+pathways simulation are studied by single-crystal X-ray diffraction and Bond Valence Site Energy (BVSE) model, respectively. The title material crystallizes in the triclinic system, space group P-1 with a = 6.521(4) Å, b = 9.623(6) Å, c = 10.969(7) Å, =64.23(2) ̊, = 80.14(3) ̊ and = 72.10(2) ̊. The structure presents Co4P4O28groups formed by two Co2O11units and two P2O7groups. The junction between these groups is assured by two pyrophosphates to create a three-dimensional anionic framework showing interconnecting tunnels in a, band caxis. The obtained structural model is supported by two validations tools: Charge Distribution (CHARDIT) analysis and Bond Valence Sum (BVS) calculation which validated the presence of Co2+and Co3+in the same sites. The Ag+cations balanced the negative charge with partial site occupations. The Ag+ pathways simulation, using the Bond Valence Site Energy(BVSE) model, identified the mobile species and proposed migration pathways of the monovalent cations according vast tunnels in three dimensions. The material must be a 3D average ionic conductor, with theoretical activation energy about 1.7 eV. Correlation between structure and electricalproperties has been discussed.

Sea cucumbers are bottom dwelling invertebrates, which are mostly found on subtropical and tropical sea grass beds, sandy reef flats, or reef slopes. Although constantly exposed to fouling communities in these habitats, many species are surprisingly free of invertebrate epibionts and microfouling algae such as diatoms. In our study, we investigated the anti-fouling (AF) activities of different crude extracts of tropical Indo-Pacific sea cucumber species against the fouling diatom Cylindrotheca closterium. Nine sea cucumber species from three genera (i.e., Holothuria, Bohadschia, Actinopyga) were selected and extracted to assess their AF activities. To verify whether the sea cucumber characteristic triterpene glycosides were responsible for the observed potent AF activities, we tested purified fractions enriched in saponins isolated from Bohadschia argus, representing one of the most active anti-fouling extracts. Saponins were quantified by vanillin-sulfuric acid colorimetric assays and identified by LC-MS and LC-MS/MS analyses. We were able to demonstrate that AF activities in sea cucumber extracts were species-specific, and growth inhibition as well as attachment of the diatom to surfaces is dependent on the saponin concentration (i.e., Actinopyga contained the highest quantities), as well as on the molecular composition and structure of the present saponins (i.e., Bivittoside D derivative was the most bioactive compound). In conclusion, the here performed AF assay represents a promising and fast method for selecting the most promising bioactive organism as well as for identifying novel compounds with potent AF activities for the discovery of potentially novel pharmacologically active natural products.

Posidonia oceanica a dominant Mediterranean Sea grass was used as a starting material to produce nanofibrillar cellulose. Thus, NFC gel was produced by the disintegration in a high pressure homogenizer of cellulose pulp extracted from P. oceanica . The ensuing NFC suspension was characterized in terms of fibrillation yield, transparency, rheological behavior and morphological features. The reinforcing potential of the ensuing NFC was also investigated using dynamic mechanical analysis (DMA) from measurements carried out on nanocomposites films prepared by casting a mixture of NFC suspension and commercial acrylic latex. The prepared materials have showed promising mechanical properties.

International audience; An impedimetric biosensor to determine the activity of phospholipase A2 has been developed for the first time. This biosensor is based on the immobilization of the enzyme phospholipase A2 (PLA2) from snake venom on the surface of a gold electrode. The enzymatic reaction takes place in the presence of the L-α -phosphatidylcholine (lecithin) substrate, in 10 mM pH 7.4 phosphate buffer. The impedance of the enzymatically modified electrode/ electrolyte interface increased as the concentration of lecithin increases. A detection limit of 10−11 M and a linear range of 10−10 M to 10−5 M were obtained. At a fixed concentration of lecithin (10−3 mM), when the PLA2 enzyme with a certain level of activity is injected, the impedance of the enzymatically modified electrode/ electrolyte interface changed in the inverse direction, due to the competitive effect of the injected PLA2 enzyme. A linear range of 10 to 400 ng/L (corresponding to 16 to 640 U/L) was obtained for commercial naja mossambica mossambica snake venom. The activity of PLA2 from naja cobra snake venom (Origin Thailand) was determined to be 75% of that of naja mossambica mossambica snake venom.

Chelating adsorbents, based on the chemical modification of silica by an efficient host able to capture toxic metals, are the most popular materials for wastewater treatment. Herein, a novel inorganic–organic hybrid material incorporating a β-keto–enol bis-heterocycle structure (SiNPz-Fn) was synthesized and the structure of the host was confirmed by single crystal X-ray diffraction. This ligand was designed to introduce active lone-pair donor systems on the silica surface. The new material has been characterized using a set of suitable physical techniques, and was found to be an efficient adsorbent for Pb(II), Zn(II), Cu(II) and Cd(II) from aqueous solution. The influence of the solution pH, contact time, initial concentration, temperature, thermodynamics and co-existing interferent substances was also studied. The adsorption kinetics of Pb(II), Zn(II), Cu(II) and Cd(II) onto SiNPz-Fn can be well fitted with a pseudo-second-order model and the adsorption capacity of this material is evaluated as 87.71, 54.64, 28.81 and 10.77 mg g−1 for Pb(II), Zn(II), Cu(II) and Cd(II), respectively. An endothermic and spontaneous process was identified. The new material was used for the extraction of metals from natural water and promises good recyclability for at least five cycles, showing great potential in practical applications.

International audience; The Mn(II) complex {[Mn(atpa)(H2O)2]·H2O}n (1),with the dicarboxylate ligand 2-aminoterephthalic acid (H2atpa), has been synthesized and crystallographically, spectroscopically and magnetically characterized. Complex 1 shows a very unusual 1κ2N,O coordination mode of the aminoterephthalate dianion with the Mn(II) ion. One of the carboxylate groups shows a syn-anti-μ2-η1:η1 binding mode to form a 2D square grid. The magnetic properties of this compound can be very well reproduced with a regular S = 5/2 chain model with a very weak antiferromagnetic coupling constant of J = −0.2 cm−1 through the single syn-anti carboxylate bridges. EPR measurement also supports the experimental data obtained from the magnetic study. The influence of the torsion angle between the carboxylate groups on the various interaction energies of 1 is calculated by means of DFT study.

00000 ăWOS:000386021300002; International audience; 1. Comparison between algal pigment analyses using HPLC and subsequent CHEMTAX analysis with microscopic counts from different lakes ranging from ultra-oligotrophic to eutrophic allowed testing of pigment: chlorophyll a ratios for lakes of different trophic conditions. Microscopic counts and pigment analyses were positively correlated for all groups except for the chrysophytes. 2. When examining the oligotrophic lakes only, microscopic analyses and pigment analyses of chrysophytes were positively correlated, which showed that the oligotrophic pigment ratios were well suited for determining the abundance of the chrysophytes in oligotrophic lakes. In the eutrophic lakes, where chrysophytes constituted less than 10% of the biomass, the weak correlation was most likely related to counting inaccuracies. 3. Chrysophytes, generally indicative of oligotrophic conditions, were three times more abundant in the oligotrophic lakes. They constituted 28% of the total phytoplankton biomass as chlorophyll a measured by the pigment method and 26% of the total phytoplankton biomass measured as biovolume by microscopy. In mesotrophic/eutrophic lakes, chrysophytes constituted only 9% (pigment method) and 8% (microscopy). 4. Similarity analyses comparing the results of these two methods on functional group level documented the high accuracy of the pigment method in detecting all the functional groups present. 5. The results of the pigment analyses showed a more even composition of phytoplankton groups than found by microscopy, where often one or two of the less abundant groups were absent or only sporadically present. The Shannon's diversity index, H', for functional groups determined from results of the pigment method were higher than the H' values based on microscopic counts, confirming a more continuous composition of the phytoplankton groups when detected by the pigment method. The pigment method was found to be a useful alternative, which supplemented microscopic counts.

7 pages; International audience; Using di-2-pyridyl ketonoxime (Hdpko) as an oxime-based ligand in combination with several polyhydric alcohols, viz. ethanediol (H2ed), propanediol (H2pd) and pentaerythritol (H4per),wehave synthesized a series of trinuclear complexes involving a linear MnII-MnIV-MnII core, viz. [Mn3(dpko)4(ed)Cl2]-2CH3CN.H2O 1, [Mn3(dpko)4(pd)Cl2].CH3CN.H2O.0.5H2pd 2 and [Mn3(dpko)4(H2per)Cl2].4H2O 3, respectively. The trinuclear complexes contain mixed valent MnII-MnIV-MnII units in a linear topology in which MnII and MnIV spin carriers are ferromagnetically coupled. The temperature dependence of the magnetic susceptibility has been fitted with a liner spin trimer model based on the H = -2J{SMn1.SMn2 + SMn10.SMn2} Heisenberg Hamiltonian with J/kB = +1.4(1) K for 1; +4.9(1) K for 2 and +3.7(1) K for 3, leading for the three complexes to an ST = 13/2 ground state.

International audience; A two-step protocol (nano-filtration and reverse osmosis) was applied for natural organic matter (NOM) preconcentration of a seawater sample. Complexing affinities of the so concentrated marine dissolved NOM (DNOM) towards major and trace cations were studied by potentiometric and voltammetric titra-tion techniques. The potentiometric titration experiments fitted by models describing and characterising the DNOM–cation interactions, revealed four distinct classes of acidic sites (pKa of 3.6, 4.8, 8.6 and 12). A total acidic sites density of 445 meq/mol C was estimated, with a majority (60%) of carboxylic-like sites. Pseudopolarographic measurements revealed two distinct groups of copper complexes: labile, reducible at about À0.2 V; and inert, directly reducible at about À1.4 V. Simultaneous competition between copper, calcium and proton highlighted the presence of two classes of binding sites (density of 1.72 and 10.25 meq mol À1 C , respectively, corresponding to 3% of total acidic sites). The first class was more specific to copper (log K CuL 9.9, log K CaL 2.5, pKa 8.6), whereas stronger competition between copper and calcium occurred for the second class (log K CuL 6.9, log K CaL 5.5, pKa 8.2). The binding sites characterisation was validated by the very good matching of the non-concentrated seawater sample titration data with the simulated curves obtained using the binding parameters from the concentrated sample. Furthermore, this comparison also validated the applied preconcentration pro-tocol, highlighting its negligible influence on organic matter properties when considering copper complexation.

International audience; The influence of an adsorbed layer of the natural organic matter (NOM) on voltammetric behaviour of copper on a mercury drop electrode in natural water samples was studied. The adsorption of NOM strongly affects the differential pulse anodic stripping voltammogram (DPASV) of copper, leading to its distortion. Phase sensitive ac voltammetry confirmed that desorption of adsorbed NOM occurs in general at accumulation potentials more negative than −1.4 V. Accordingly, an application of negative potential (−1.6 V) for a very short time at the end of the accumulation time (1% of total accumulation time) to remove the adsorbed NOM was introduced in the measuring procedure. Using this protocol, a well-resolved peak without interferences was obtained. It was shown that stripping chronopotentiogram of copper (SCP) in the depletive mode is influenced by the adsorbed layer in the same manner as DPASV. The influence of the adsorbed NOM on pseudopolarographic measurements of copper and on determination of copper complexing capacity (CuCC) was demonstrated. A shift of the peak potential and the change of the half-peak width on the accumula-tion potential (for pseudopolarography) and on copper concentration in solution (for CuCC) were observed. By applying a desorption step these effects vanished, yielding different final results.

The reactions of the CN − and C 3 N − anions with cyanoacetylene HC 3 N, of special interest for the chemistry of Titan’s upper atmosphere, have been investigated by means of FTICR mass-spectrometry. Primary ions, CN − and C 3 N − , have been produced by dissociative electron attachment (DEA) from BrCN and BrC 3 N, and prepared in a clean way before reaction. Total rate constants have been measured for both reactions at 300 K and are found to be as follows: (3.9 ± 0.5) × 10 −9 and (1.0 ± 0.2) × 10 −10 cm 3 s −1 for the reaction of HC 3 N with CN − and C 3 N − , respectively. For the CN − + HC 3 N reaction, proton transfer is found to be the only reactive channel within our detection limits. Proton transfer is also dominant for the C 3 N − + HC 3 N reaction but the resulting ionic product being identical to the primary ion C 3 N − , this process is transparent for the kinetics of the C 3 N − + HC 3 N reaction and the kinetic rate retrieved corresponds to a slow and competitive detachment pathway. Yet the nature and energetics of the neutral product(s) formed through this process remain unknown. Additional experiments using isotopic products have allowed to retrieve specific rate constants associated with the proton transfer channel in the C 3 15 N − + HC 3 N and C 3 N − + HC 3 15 N reactions and the measured rates are found to be significantly lower than for the CN − + HC 3 N system. This decrease and the evolution of reactivity when going from CN − to C 3 N − and the opening of a new detachment pathway are finally discussed.

International audience; The direct mode of scanning electrochemical microscopy (SECM) was used for the local deposition of oligonucleotide (ODN) patterns on thin gold films and the generation-collection (GC) mode was applied for the determining the amount of surface-accessible oligonucleotides. The local deposition was achieved through the micrometer-sized formation of a conducting polymer bearing 15mer single-stranded oligonucleotide strands. After the interaction of the oligonucleotide with its biotin-labeled complimentary strand, streptavidin was bound. The molecular assembly was completed by linking biotin-labeled -galactosidase from Escherichia coli to the streptavidin. The activity of the linked β-galactosidase was mapped with SECM in the GC mode by monitoring the oxidation of p-aminophenol (PAP) formed in the enzyme-catalyzed hydrolysis of p-aminophenyl-β-D-galactopyranoside. The feedback effect due to recycling of the reaction product at the gold surface was analyzed. It was shown experimentally that this effect becomes insignificant at ultramicroelectrode (UME)-substrate distances larger than 3 UME radii. The flux of formed PAP allowed the determination the surface density of accessible oligonucleotide strands in the functionalized polymer. It was shown that that thicker pyrrole/ODN-Pyrrole polymer films do not lead to a significantly increased accessible ODN surface concentration.

International audience; Distributions of trace metals (TM), organic carbon, SPM and physico-chemical parameters were studied in the highly stratified Krka River estuary in winter/summer periods. The non-conservative behaviour of Zn, Cd, Pb and Cu in the brackish layer (plume), easily spotted due to very low inputs by the river, was mainly caused by their inputs from the pleasure boats, nautical marinas and harbour (e.g. release from antifouling paints). Contrarily, Ni and Co followed near-conservative behaviour. The extremely low SPM discharged by the river, resulted in a predominant dissolved fraction (\textgreater80%) of all TM, except Pb. Vertical scavenging, coupled with the long residence time, caused accumulation and progressive upstream increase of TM and SPM in the bottom seawater. Decrease of distribution coefficient (4) in the brackish layer for winter period was ascribed to the change of SPM nature (terrestrial vs. biogenic), whereas a variable and increased biogenic component of SPM caused scattered K(D)s in summer. (C) 2015 Elsevier Ltd. All rights reserved.

The combination of analysis, multivariate treatment (PCA) and chemical speciation calculation confirmed the control of Fe, Mn, sulphide and organic matter on metals dynamics in coastal sediments (0–5 cm surface sediments and sediments cores) of Toulon Bay (NW Mediterranean). The temporal monitoring of the physic-chemical parameters as well as the dissolved/particulate minor (Fe/Mn) and trace elements (i.e. Ag, Cd, Co, Cu, Ni, Pb, Zn, …) concentrations in porewaters and sediments were assessed. Multivariate treatment revealed different behaviours for marine elements, terrestrial ones and contaminants. Seasonal variations of metals mobilization in porewater were observed, related to diagenesis activity. Element mobility was studied by selective extractions (ascorbate, acid and alkaline) on sediments. Thermodynamic simulation (PHREEQC) was performed to calculate the elemental dissolved speciation, the mineral saturation index and then to simulate the solid/liquid interaction through precipitation processes, studying the contrasted influence of dissolved organic matter and sulphide.

International audience; The objective of this study was to examine the occurrence of parabens (5 congeners), triclosan (TCS) and triclocarban (TCC) at the scale of the Parisian sewer network and to provide representative knowledge on these compounds in France for a large area. For this purpose and in collaboration with the Parisian public sanitation service (SIAAP) in charge of the collect and treatment of the Parisian wastewater, this study focused on seven main sewer trunks of the Paris conurbation, accounting for 1900,000 m(3) d(-1), i.e., about 8 million inhabitants. Concentrations lying in the 2000-20000 ng l(-1) ranges were found in wastewater, confirming the ubiquity of parabens, TCS and TCC in our environment and household products. Parabens (>97%) and to a lesser extent TCS (68% in median) were mainly associated to the dissolved fraction, as demonstrated by low KD and KOC values. For the first time, this study also evaluated the pollutant mass loads per population equivalent (PE) of parabens, TCS and TCC at the large and representative scale of the Parisian conurbation. Hence, the median mass loads varied from 176 to 3040 μg PE(-1) d(-1) for parabens and from 26 to 762 μg PE(-1) d(-1) for TCS and TCC. Based on these results and according to the assumptions done, the extrapolation of the mass loads at the national scale pointed out an annual mass loads between 51.8 and 100.7 ty(-1) for methyl paraben (MeP) and between 11.2 and 23.5 ty(-1) for TCS. Mass loads per equivalent habitant and national mass loads are both extremely relevant and innovative data. Contrary to other countries, such data are nowadays rather difficult to gain in France and neither enquiry nor database provides access to information on the use and production of these chemicals. Since cosmetic industries are voluntarily and fully engaged in the substitution of parabens, triclosan and triclocarban in personal care product, this study could constitute a "time reference status" which could be used as a basis for future monitoring.

Many advances in nanomaterials synthesis have been recorded during the last 30 years. Bacterial cellulose (BC) produced by bacteria belonging to the genera Acetobacter, Rhizobium, Agrobacterium, and Sarcina is acquiring major importance as one of many eco-friendly materials with great potential in the biomedical field. The shape of BC bulk is sensitive to the container shape and incubation conditions such as agitation, carbon source, rate of oxygenation, electromagnetic radiation, temperature, and pH. The challenge is to control the dimension and the final shape of biosynthesized cellulose, by the optimization of culture conditions. The production of 3D structures based on BC is important for many industrial and biomedical applications such as paper and textile industries, biological implants, burn dressing material, and scaffolds for tissue regeneration. In our work, wild strains of Acetobacter spp. were isolated from homemade vinegar then purified and used for cellulose production. Four media of different initial viscosity were used. Cultures were performed under static conditions at 29°C, in darkness. The dimensions and texture of obtained bacterial cellulose nanofibers were studied using scanning electron microscopy (SEM). X-ray diffraction (XRD) showed that the biosynthesized material has a cellulose I crystalline phase characterized by three crystal planes. fourrier transform infrared spectroscopy (FTIR) data confirmed the chemical nature of the fibers. Thermo-gravimetric analysis (TGA) showed that BC preserves a relatively superior non-degradable fraction compared to microcrystalline cellulose.

International audience; The marine chemistry of iodine has been studied in the marine lake, Mir, regarded as a natural reactor situated in the karstificated carbonate rocks of the Croatian Adriatic coast. The investigation covered the major variables: salinity, temperature, dissolved oxygen, pH and alkalinity, some nutrients, organic carbon, and iodide, iodate and organic-I. Lake Mir was found to be meso-trophic, with dynamic nutrient cycling of a magnitude usually associated with the temperate zone but within a Mediterranean clime. An essentially U-shaped pattern exists in the plot of nutrient concentration versus time for the June–November period studied. Together, the major variables and the nutrient chemistry confirm that Lake Mir is essentially isolated from the nearby (90 m) Adriatic seawater, and this also may explain the meso-trophic nature of the lake, with dry and wet deposition as the source of the extra nutrient. It is of note that iodate was essentially absent from Mir during the sampling period. This appears to be consistent with iodine's behaviour in the oceans in general, where iodate is reduced generally as a result of the presence of the biota. The chemistry of iodine in Lake Mir is consequently dominated by changes in iodide and organic-I concentrations, with the latter at higher concentrations than those found in seawater. Even so, the total iodine concentration in Mir is only about one-quarter of that in the adjacent Adriatic seawater, and again it is argued that this is probably a function of Lake Mir's isolation.

International audience; A study of foams formed on the marine Lake Mir, Croatia, and elsewhere on the same coast demonstrates, for the first time, that they are fractionated (enrichened) in org-I by up to 630 times relative to the water from which they form. The results are consistent with an I/C mole ratio for in-situ organic matter. Foams created artificially in the laboratory from natural samples of water from Lake Mir were similarly fractionated, although to a lesser degree. These differences were effectively removed when enrichments were expressed as molar ratios, e.g., Ptot/Itot, rather than straightforward concentrations. This similarity in the behaviour to enrichment for organic forms of I, N and P suggests that the time over which foams age is a major determinant of the enrichment they display. It is argued that this period allows time for the seawater occluded in the interstitial spaces between bubbles, to drain away. Since foam production is ubiquitous over the oceans it seems likely that this process local to coastal environments is much more common than at first might appear to be the case. The paper explains how this work provides circumstantial evidence that the bubble-bursting mechanism current since the 1960s may well provide the iodine which appears to be missing in many modelling calculations based upon an atmospheric system dependant upon sorption of the species IO upon the marine aerosol.

International audience; The alkylation of (dichlorotantala)-p-tert-butylcalix[4]arenes 1 and 3 by two equivalents of NpMgCl (Np = neopentyl) affords the corresponding unreported (bisneopentyltantala)-p-tert-butylcalix[4]arenes 4 and S. These complexes can undergo dealkylation by modest increase of the temperature to yield 6 and 7. The characterization and structural conformation of the complexes 6 and 7 were determined by H-1, C-13, NOESY, and COSY spectroscopic studies and single-crystal X-ray diffraction. 7 exhibits unprecedented use of an intramolecular C H activation of an aromatic ring and simultaneously releases of one equivalent of neopentane. DFT calculation supports a mechanism in which the metal passes through a transition state involving a coplanar arrangement with its three ligands (C-Ar, H-Ar., C-Np).

Made available in DSpace on 2022-04-29T08:44:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-12 Analysis of fuel emissions is crucial for understanding the pathogenesis of mortality because of air pollution. The objective of this study is to assess cardiovascular and inflammatory toxicity of diesel and biodiesel particles. Mice were exposed to fuels for 1 h. Heart rate (HR), heart rate variability, and blood pressure were obtained before exposure, as well as 30 and 60 min after exposure. After 24 h, bronchoalveolar lavage, blood, and bone marrow were collected to evaluate inflammation. B100 decreased the following emission parameters: mass, black carbon, metals, CO, polycyclic aromatic hydrocarbons, and volatile organic compounds compared with B50 and diesel; root mean square of successive differences in the heart beat interval increased with diesel (p < 0.05) compared with control; low frequency increased with diesel (p < 0.01) and B100 (p < 0.05) compared with control; HR increased with B100 (p < 0.05) compared with control; mean corpuscular volume increased with B100 compared with diesel (p < 0.01), B50, and control (p < 0.001); mean corpuscular hemoglobin concentration decreased with B100 compared with B50 (p < 0.001) and control (p < 0.05); leucocytes increased with B50 compared with diesel (p < 0.05); platelets increased with B100 compared with diesel and control (p < 0.05); reticulocytes increased with B50 compared with diesel, control (p < 0.01), and B100 (p < 0.05); metamyelocytes increased with B50 and B100 compared with diesel (p < 0.05); neutrophils increased with diesel and B50 compared with control (p < 0.05); and macrophages increased with diesel (p < 0.01), B50, and B100 (p < 0.05) compared with control. Biodiesel was more toxic than diesel because it promoted cardiovascular alterations as well as pulmonary and systemic inflammation. © The Author 2010. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please email: journals.permissions@oxfordjournals.org. Laboratory of Experimental Air Pollution, Department of Pathology and School of Medicine, University of São Paulo, 01246-903 São Paulo Laboratory of Experimental Therapeutics, Department of Medicine, School of Medicine, University of São Paulo, 01246-903 São Paulo Department of Analytical Chemistry, Institute of Chemistry, University of Estate of São Paulo, 14801-970 Araraquara (SP) Laboratory of Atmospheric Chemistry, Center for Chemistry and Environment, Institute of Researches and Nuclear Energy, 05508-900 São Paulo

The hydrothermal reaction of 5-aminoisophthalic acid and praseodymium oxide in different acids results in two new praseodymium coordination polymers, {Pr(2)(aip)(3)(H(2)O)(2) x 3 H(2)O}(n) (1) and {Pr(2)(Haip)(2)(aip)(NO(3))(2) x 8 H(2)O}(n) (2) (aip = 5-aminoisophthalate). Complexes 1 and 2 are two distinct three-dimensional metal-organic frameworks constructed from the linkage of rod-shaped praseodymium carboxylate secondary building units and phenyl rings. Both dehydrated coordination frameworks are estimated using a computational method based on Connolly's algorithm, indicating that dehydrated compound 1 cannot host molecules other than water molecules or He, whereas dehydrated compound 2 is able to host molecules with kinetic radii as big as 2.3 A. The potential specific accessible surface of this compound is 792 m(2) g(-1). Meanwhile, N(2) sorption measurements reveal that dehydrated compound 2 having a high 230 cm(3)/g (287 mg/g) N(2) storage capacity at 77 K and 1 atm is in fairly good agreement with our calculation results. Moreover, powder X-ray diffraction measurement results demonstrated that the stable channels of dehydrated compound 2 can reversibly host other small solvent molecules (e.g., water, methanol, and ethanol) and grand canonical Monte Carlo simulation is applied to predict its hydrogen storage capacity.

International audience; Oxidized boron-doped diamond (BDD) electrodes were coated with a monolayer of n-octadecyltrichlorosilane as well as of other silanes. Scanning force microscopy was applied to pattern these monolayers, utilizing doped diamond-coated conductive probes. Patterns were generated on the nanometer scale, and conditions for the patterning process were quantified with regard to humidity and potential bias. It was observed that a sample bias of 3-3.5 V and a relative humidity > 70% are necessary to generate reproducible and stable patterns. At potentials and relative humidities below these values, no or incomplete removal of the monolayer occurred. The results show that electro-oxidative patterning is an expedient way for the generation of nanostructures on chemically modified BDD.

International audience; An interaction of dissolved natural organic matter (DNOM) with copper ions in the water column of the stratified Krka River estuary (Croatia) was studied. The experimental methodology was based on the differential pulse anodic stripping voltammetric (DPASV) determination of labile copper species by titrating the sample using increments of copper additions uniformly distributed on the logarithmic scale. A classical at-equilibrium approach (determination of copper complexing capacity, CuCC) and a kinetic approach (tracing of equilibrium reconstitution) of copper complexation were considered and compared. A model of discrete distribution of organic ligands forming inert copper complexes was applied. For both approaches, a home-written fitting program was used for the determination of apparent stability constants (K i equ), total ligands concentration (L iT) and association/dissociation rate constants (k i 1 ,k i -1). A non-conservative behaviour of dissolved organic matter (DOC) and total copper concentration in a water column was registered. An enhanced biological activity at the freshwater–seawater interface (FSI) triggered an increase of total copper concentration and total ligand concentration in this water layer. The copper complexation in fresh water of Krka River was characterised by one type of binding ligands, while in most of the estuarine and marine samples two classes of ligands were identified. The distribution of apparent stability constants (log K 1 equ : 11.2–13.0, log K 2 equ :8.8–10.0) showed increasing trend towards higher salinities, indicating stronger copper complexation by autochthonous seawater organic matter. Copper complexation parameters (ligand concentrations and apparent stability constants) obtained by at-equilibrium model are in very good accordance with those of kinetic model. Calculated association rate constants (k 1 1 :6.1–20 × 10 3 (M s) − 1 , k 2 1 : 1.3–6.3 × 10 3 (M s) − 1) indicate that copper complexation by DNOM takes place relatively slowly. The time needed to achieve a new pseudo-equilibrium induced by an increase of copper concentration (which is common for Krka River estuary during summer period due to the nautical traffic), is estimated to be from 2 to 4 h. It is found that in such oligotrophic environment (dissolved organic carbon content under 83 µM C , i.e. 1 mg C L − 1) an increase of the total copper concentration above 12 nM could enhance a free copper concentration exceeding the level considered as potentially toxic for microorganisms (10 pM).

International audience; Ultrathin titanium layers when deposited on the surface of gold can be successfully applied for infrared reflection absorption spectroscopy (IRRAS) investigations. It was shown that the reflectivity, the phase shift, and the mean square electric field of the p- and s-polarized IR radiation in up to 20 nm thick titanium layers covered with a 3−4 nm thick layer of native oxide are comparable to those of the air/gold interface. The surface selection rule is fulfilled. Thus, qualitative and quantitative analysis of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) bilayers transferred in liquid expanded (LE) and liquid condensed (LC) states can be performed. Differences are found in the hydration state and molecular arrangement of the two investigated bilayers. In the DMPC bilayer in the LE state, the C−N bond in the positively charged choline moiety is inclined by ~70° toward the surface of the negatively charged titanium substrate. In the phosphate moiety, the in-plane vector of the O−P−O group makes a small angle of ~15° to the surface normal. This open structure of the lipid molecule corresponds to the B crystal structure of the DMPC molecule and provides space for strong hydration of the polar headgroup. In the DMPC bilayer in the LC state, the intermolecular distances are reduced; the C−N bond of the choline group makes a smaller angle to the surface normal, and the in-plane vector of the O−P−O group in the phosphate moiety displays a larger tilt. The degree of hydration is reduced. The arrangement of the polar headgroup region corresponds to the A crystal structure of the DMPC molecule.

International audience; The interaction of dissolved organic matter (DOM) with copper and zinc in a concentrated seawater sample was characterised by pseudopolarography. Measurements performed at increased concentrations of copper(II) ions showed successive saturation of active DOM sites which indicate possible partition of copper between (i) free or labile complexes, (ii) reduced and released within the potential window of the method, and (iii) electroinactive copper complexes. Pseudopolarograms measured at pH 4 indicate a release of copper which was bound to the active sites of DOM that formed non-labile complexes. Variation of the peak position and half-peak width along the scanned deposition potentials and with the increasing concentration of copper bear the information about the complex electrochemical processes at the electrode surface and in the bulk of the solution. Pseudopolarograms of zinc showed a strong dependence of the peak current and the peak position along the scanned deposition potentials on pH values, indicating preferentially complexation of zinc with carboxylic-like active sites of DOM in the measured sample. Pseudopolarography is a valuable method in the trace metal complexation and speciation studies, serving as a fingerprint of the analysed sample.

International audience; Hydrothermal reaction of diaminomaleonitrile and copper salts under different conditions resulted in copper cyanide coordination polymers {[Cu(H2O)(NH3)4][Cu3(CN)5] · H2O}n (1), {(CH3)4N[Cu(H2O)(NH3)4][Cu4(CN)7]}n (2), and {(CH3OH2)2[Cu2(CN)3]}n (3). 1 and 2 are new mixed-valence Cu(I,II), two 3D organic-inorganic molecular framework complexes that exhibit ionic inclusion. 3 is an open copper cyanide framework hosting a guest molecule. Cyanides in 1, 2, and 3 are produced by in situ C-C bond cleavage of diaminomaleonitrile, and then the remaining product is oxidized to form an oxalate group. The potential porosity of the hydrated coordination polymer 3 was estimated using a computational method based on Connolly's algorithm.

International audience; Polarization modulation infrared reflection absorption spectroscopy (PM IRRAS) was successfully used for the first time to characterize an optically transparent thin oxide film. SiO2 layers of 7 nm thickness were synthesized by plasma enhanced chemical vapor deposition (PECVD) on 200 nm thick gold covered glass slides. Despite the fact that silica is transparent and absorptive to IR radiation when deposited in the form of thin films on a gold surface, it preserves the high metallic reflectivity for the IR light. At grazing angles of incidence of the IR beam, the enhancement of the normal component of the electric field at the interface is comparable to that of Au alone. In addition, the analysis of the structure of a 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid monolayer deposited using the Langmuir−Blodgett technique is demonstrated.

International audience; This paper describes the functionalization of oxidized boron-doped diamond (BDD) electrodes with N-(3-trimethoxysilylpropyl)pyrrole (TMPP) and the influence of this layer on the electrochemical transfer kinetics as well as on the possibility of forming strongly adhesive polypyrrole films on the BDD interface through electropolymerization. Furthermore, localized polymer formation was achieved on the TMPP-modified BDD interface using the direct mode of a scanning electrochemical microscope (SECM) as well as an electrochemical scanning near-field optical microscope (E-SNOM). Depending on the method used polypyrrole dots with diameters in the range of 1–250 μm are electrogenerated.