Éditeur(s) : HAL CCSD National Institute of Environmental Health Sciences
Résumé : International audience
BACKGROUND: Glycol ethers are present in a wide range of occupational and domestic products. Animal studies have suggested that some of them may affect ovarian function. OBJECTIVE: To study the relation between women's exposure to glycol ethers and time to pregnancy. METHODS: Urine from randomly selected women in the PELAGIE mother-child cohort who had samples collected before 19 weeks of gestation was tested to measure eight glycol ether metabolites by chromatography coupled to mass spectrometry. Time to pregnancy was collected at the beginning of the pregnancy by asking women how many months they took to conceive. Associations between metabolite levels and time to pregnancy were estimated in 519 women with complete data using discrete-time Cox proportional hazards models to adjust for potential confounders. RESULTS: Glycol ether metabolites were detected in 6% (for ethoxyacetic acid) to 93% (for phenoxyacetic and butoxyacetic acids) of urine samples. Phenoxyacetic acid was the only metabolite with a statistically significant association with longer time to pregnancy (fecundability OR 0.82; 95% CI: 0.63, 1.06 for the second and third quartile combined; fecundability OR 0.70; 95% CI: 0.52, 0.95 for a fourth-quartile (≥1.38 mg/L) vs. first-quartile concentration (<0.14 mg/L)). This association remained stable after multiple sensitivity analyses. CONCLUSION: Phenoxyacetic acid, which was present in most of the urine samples tested in our study, was associated with increased time to pregnancy. This metabolite and its main parent compound, 2-phenoxyethanol, are plausible causes of decreased fecundability, but may also be surrogates for potential co-exposures frequently present in cosmetics.
ISSN: 0091-6765

hal-00866023
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00866023
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00866023/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00866023/file/Urinary_Glycol_Ether-accepted.pdf
DOI : 10.1289/ehp.1206103

Éditeur(s) : HAL CCSD Elsevier
Résumé : Remerciements :- Dr. Jacques Delabie- Andrea Yockey-Dejean- Geoff Brown- Jean-Pierre Andrieu
Background: Most ant venoms consist predominantly of small linear peptides, although some contain disulfide linked peptides as minor components. However, in striking contrast to other ant species, some Anochetus venoms are composed primarily of disulfide-rich peptides. In this study, we investigated the venom of the ant Anochetus emarginatus with the aim of exploring these novel disulfide-rich peptides.Methods: The venom peptidome was initially investigated using a combination of reversed-phase HPLC and mass spectrometry, then the amino acid sequences of the major peptides were determined using a combination of Edman degradation and de novo MS/MS sequencing. We focused on one of these peptides, U-1-PONTX-Ae1a (Ae1a), because of its novel sequence, which we predicted would form a novel 3D fold. Ae1a was chemically synthesized using Fmoc chemistry and its 3D structure was elucidated using NMR spectroscopy. The peptide was then tested for insecticidal activity and its effect on a range of human ion channels.Results: Seven peptides named poneritoxins (PONTXs) were isolated and sequenced. The three-dimensional structure of synthetic Ae1a revealed a novel, compact scaffold in which a C-terminal beta-hairpin is connected to the N-terminal region via two disulfide bonds. Synthetic Ae1a reversibly paralyzed blowflies and inhibited human L-type voltage-gated calcium channels (Ca(v)1).Conclusions: Poneritoxins from Anochetus emarginatus venom are a novel class of toxins that are structurally unique among animal venoms.General significance: This study demonstrates that Anochetus ant venoms are a rich source of novel ion channel modulating peptides, some of which might be useful leads for the development of biopesticides.
ISSN: 0304-4165

hal-01511987
https://hal.archives-ouvertes.fr/hal-01511987
https://hal.archives-ouvertes.fr/hal-01511987/document
https://hal.archives-ouvertes.fr/hal-01511987/file/2016_Touchard_Biochimica_Biophysica_%7B4B3BE6A3-AE83-4C6E-B678-BBFB5CC84AF7%7D.pdf
DOI : 10.1016/j.bbagen.2016.07.027

Éditeur(s) : HAL CCSD The Royal Society of Chemistry
Résumé : International audience
This review is devoted to the description of synthetic strategies for glycodendrimers synthesis. Dendrimers can be classified into three categories: carbohydrate-coated, carbohydrate-centered and carbohydrate-based dendrimer. In this paper we will focus on the third one, in which the core unit is originated from a monosaccharide. Compare to classical Pamam, Boltorn cores, carbohydrate units add much more three dimension information, coded in the chirality in almost each carbon. Various coupling chemistry have been developed and are presented here: glycosylation, amide bound formation, and click chemistry (thiol-ene reaction, epoxide - thiol reaction).
Carbohydrate Chemistry: Volume 40

ISBN : 978-1-84973-965-8
hal-01362709
https://hal.archives-ouvertes.fr/hal-01362709
DOI : 10.1039/9781849739986-00257

Éditeur(s) : HAL CCSD American Physical Society
Résumé : We study the equilibrium properties of a liquid phase condensed at the nanoscale between the surfaces of a sharp crack in fused silica in a moist controlled atmosphere. The extension of the condensed phase along the fracture is measured by in situ atomic force microscopy phase imaging and it is shown to be determined by a critical distance between the opposite crack surfaces, which is an increasing function of humidity. The present technique is very promising for measuring the properties of confined liquids at the nanoscale as well as for modeling the physics and chemistry of slow crack propagation in glasses.
ISSN: 0031-9007

hal-00411946
https://hal.archives-ouvertes.fr/hal-00411946
DOI : 10.1103/PhysRevLett.100.165505

Éditeur(s) : HAL CCSD
Résumé : Biogenic volatile organic compound (BVOCs) emissions play an important role in regional air quality and global atmospheric chemistry. In addition, these natural VOC emissions serve important biological functions including attracting and repelling pollinators and herbivores. Some biological organisms use ambient air as a communication medium and the oxidation of these compounds brings about the concentration gradients sensed by insects and other organisms. Isoprene is the predominant BVOC emitted by vegetation and tropical forests are the dominant global source. This compound is very reactive in the atmosphere and contributes to the reactions that control tropospheric oxidant concentrations and thus the concentrations and lifetimes of longer-lived species. This paper presents a study on the seasonal variations in isoprene and some other significant BVOCs such as µ-pinene, µ-pinene, limonene, e-µ ocimene and longifolene, measured at the Guyaflux Tower located in a wet tropical forest in Paracou French Guiana (5o16´54´´N, 52o54´44´´W), during the year of 2011, using the Relaxed Eddy Accumulation technique at approximately 20 meters high above the canopy. The results show a lower concentration of isoprene during the month of February and March which correspond to the wet season with an average of 0,545 µg/m3 and 0,341 µg/m3, respectively followed by a slight increase in middle April (still wet season) and a higher concentration later in mid-June. The same behavior was observed for µ-pinene with higher concentrations for the same periods as isoprene however with a smaller increase. All the other compounds had concentrations below 1 µg/m3during the whole year: The monoterpene, e-µ ocimene, was observed and is known as a stress compound but the vegetation at the site did not face any known severe stress condition such as excessive drought or flooding. Concerning the fluxes, the results showed that just a small amount of BVOCs were deposited by wet or dry process and the majority of them were released in the atmosphere. Isoprene was by far the biogenic volatile organic compound with the highest concentration and flux, followed by alpha-pinene. The lowest concentration and flux rate for all the studied compounds was observed during the months of March and late July and beginning of August indicating a lower production of those BVOCs by vegetation during those periods. Previous limited studies in Amazonia and the Congo suggested that a higher concentration and flux rate of isoprene and µ-pinene should be expected during the dry season with lower emissions during the wet season, which is in relative agreement with what was observed at this tropical forest site in French Guiana. The exceptions were observed in April and June which correspond to a long wet period in which the concentration of isoprene and µ-pinene increased more than it was expected for this time of the year. The observations will be compared to output from the global chemistry transport model CAM-chem, which includes the MEGAN biogenic emissions model.
10th EGU General Assembly
vienne, Austria

hal-01204214
https://hal.archives-ouvertes.fr/hal-01204214
PRODINRA : 276525

Éditeur(s) : Counc. Meet. of the Int. Counc. for the Exploration of the Sea, La Rochelle (France), 26 Sep-4 Oct 1991
Résumé : The oyster population in the Maryland portion of the Chesapeake Bay has declined b y more than 38-fold since the early part of the century. Although the effects of fishing have been implicated, the decline has been attributed primarily to water quality and recently oyster disease. The decline has also been thought to have affected the biota and chemistry of the Bay. Our analysis provides a quantitative demonstration that the long-term declines are largely the result of habitat loss related to over fishing early in the century, stock over fishing, early in the century' through the recent times. Furthermore, the major ecological effects on Chesapeake Bay occurred well-before World War 1/, before industrialization and the prevalence of disease

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1991/acte-3058.pdf
http://archimer.ifremer.fr/doc/00000/3058/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We investigate the timing of end of motion along the South Tibet Detachment System (STDS), a major normal fault system that runs parallel to the Himalayan range for more than 1500 km. Near Dinggye (similar to 28 degrees 10'N, 87 degrees 40'E), the STD dips similar to 10 +/- 5 degrees to the North and separates Paleozoic Tethyan series from Upper Himalayan Crystalline Series (UHCS). Immediately below the STD, the UHCS is highly deformed in the STD shear zone, lineations trend NNE and the shear senses are top to the NE. In micaschist, the P-T path constrained by pseudosection and garnet chemistry, shows successive metamorphic conditions of similar to 0.6 GPa and similar to 550 degrees C and 0.5 GPa and 625 degrees C. U/Pb dating of monazites and zircons in deformed and undeformed leucogranites suggests that ductile deformation lasted until at least similar to 16 Ma but ended prior to similar to 15 Ma in the STD shear zone similar to 100 m below the detachment. Ar/Ar micas ages in the footwall span between similar to 14.6 and 13.6 Ma, indicating rapid cooling down to similar to 320 degrees C, and suggesting persistence of normal faulting, at that time. The STDS is cut and offset by the N-S trending Dinggye active normal fault which initiated prior to 11 Ma thus providing a minimum bound for the end of STDS motion. These data are interpreted as reflecting 0.3 GPa (11 km) to 0.6 GPa (22 km) of exhumation along the STDS starting prior to similar to 16 Ma, ending between 13.6 and 11 Ma. The 1000 km long stretch of the STDS east of the Gurla Mandata probably stopped almost synchronously between 13 and 11 Ma ago, coevally with a sudden switch from NNE-SSW to E-W extension at the top of the accretionary prism, with a jump of the major thrust from the lower Main Central Thrust (MCTI) to the Main Boundary Thrust (MBT), and with a change in the India and Asia convergence direction. This synchronism is probably better explained in the frame of a thrust wedge or thrust system model than a lower channel flow model. West of the Gurla Mandata the STDS appears to stop 5 to 3 Ma earlier, possibly related to local interactions with the Karakorum fault in a way that needs to be understood.
ISSN: 0012-821X

hal-00475652
https://hal.archives-ouvertes.fr/hal-00475652
DOI : 10.1016/j.epsl.2009.12.035

Éditeur(s) : HAL CCSD Royal Society of Chemistry
Résumé : International audience
A series of graphene oxide (GO) and zinc partially substituted magnetite GO-Fe1-xZnxOy (0 ≤ x ≤ 0.285) catalysts were synthesised through a precipitation-oxidation method. The rate constants for the degradation of acid orange seven (AO7) proceeded at a significant faster rate under UV-irradiation (up to 670%) than the conventional heterogeneous Fenton-like reaction. The resultant catalysts were mesoporous, so there was no mass transfer limitation for AO7 to access active sites in the catalysts. Further, maximum increases of rate constant up to 220% occurred as the zinc molar concentration increased from x = 0 to x = 0.159. GO enhanced to incorporation of zinc into the combined metal oxide, whilst zinc limited crystal growth, thus forming smaller crystallite sizes. These features proved to be essential for the improved catalytic activity of the resultant catalysts. The optimised zinc molar value at x = 0.159 delivered the best catalytic activity. © The Royal Society of Chemistry 2016.
ISSN: 2046-2069

hal-01683215
https://hal.univ-antilles.fr/hal-01683215
DOI : 10.1039/c6ra04068c

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Porous thin films considered for applications like separation, sensing and microelectronic have to sustain mechanical stresses during their integration process or in working conditions. Thanks to recent progress in processing methods, it is now possible to precisely control the porosity and combine ordered mesopores with randomly-distributed macropores to achieve hierarchically porous materials. The mechanical properties of thin films containing different types of porosity (ordered meso, random macro and hierarchical) have been investigated by means of nanoindentation. In particular a method recently proposed by Li and Vlassak (H. Li, J.J. Vlassak, Journal of Materials Research 24 (2009) 1114-1126) is applied to account for the substrate effect. Residual indent impressions were imaged by Atomic Force Microscopy (AFM) to provide some insights in the mechanical behavior of the films. In addition, experimental indentation moduli are compared to theoretical predictions obtained via Finite Element (FE) analysis. The different porous structures have been modeled by FE to obtain the effective elastic properties from which the indentation modulus can be inferred. Finally, the experimental-model differences are discussed. © 2010 Elsevier Inc. All rights reserved.
ISSN: 1387-1811

hal-01683194
https://hal.univ-antilles.fr/hal-01683194
DOI : 10.1016/j.micromeso.2010.09.004

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Although first-order rate constants are basic ingredients of physical chemistry, biochemistry and systems modeling, their innermost nature is derived from complex physical chemistry mechanisms. The present study suggests that equivalent conclusions can be more straightly obtained from simple statistics. The different facets of kinetic constants are first classified and clarified with respect to time and energy and the equivalences between traditional flux rate and modern probabilistic modeling are summarized. Then, a naive but rigorous approach is proposed to concretely perceive how the Arrhenius law naturally emerges from the geometric distribution. It appears that (1) the distribution in time of chemical events as well as (2) their mean frequency, are both dictated by randomness only and as such, are accurately described by time-based and spatial exponential processes respectively.
Physica A: Statistical Mechanics and its Applications

hal-00845518
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00845518
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00845518v2/document
ARXIV : 1307.4583
DOI : 10.1016/j.physa.2013.05.036

Éditeur(s) : HAL CCSD
Résumé : International audience
Catalysis Today

hal-01683192
https://hal.univ-antilles.fr/hal-01683192
DOI : 10.1016/j.cattod.2010.04.025

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Long-term exposure to air pollution (AP) has been shown to have an impact on mortality in numerous countries, but since 2005 no data exists for France. We analyzed the association between long-term exposure to air pollution and mortality at the individual level in a large French cohort followed from 1989 to 2013. The study sample consisted of 20,327 adults working at the French national electricity and gas company EDF-GDF. Annual exposure to PM10, PM10–2.5, PM2.5, NO2, O3, SO2, and benzene was assessed for the place of residence of participants using a chemistry-transport model and taking residential history into account. Hazard ratios were estimated using a Cox proportional-hazards regression model, adjusted for selected individual and contextual risk factors. Hazard ratios were computed for an interquartile range (IQR) increase in air pollutant concentrations. The cohort recorded 1967 non-accidental deaths. Long-term exposures to baseline PM2.5, PM10-25, NO2 and benzene were associated with an increase in non-accidental mortality (Hazard Ratio, HR = 1.09; 95% CI: 0.99, 1.20 per 5.9 μg/m3, PM10-25; HR = 1.09; 95% CI: 1.04, 1.15 per 2.2 μg/m3, NO2: HR = 1.14; 95% CI: 0.99, 1.31 per 19.3 μg/m3 and benzene: HR = 1.10; 95% CI: 1.00, 1.22 per 1.7 μg/m3).The strongest association was found for PM10: HR = 1.14; 95% CI: 1.05, 1.25 per 7.8 μg/m3. PM10, PM10-25 and SO2 were associated with non-accidental mortality when using time varying exposure. No significant associations were observed between air pollution and cardiovascular and respiratory mortality. Long-term exposure to fine particles, nitrogen dioxide, sulfur dioxide and benzene is associated with an increased risk of non-accidental mortality in France. Our results strengthen existing evidence that outdoor air pollution is a significant environmental risk factor for mortality. Due to the limited sample size and the nature of our study (occupational), further investigations are needed in France with a larger representative population sample.
ISSN: 0160-4120

hal-01187145
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187145
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187145/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187145/file/Association%20between%20long-term%20exposure%20to%20air%20pollution%20and%20mortality_accepted.pdf
DOI : 10.1016/j.envint.2015.08.006

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : In habitat mosaics, plant populations face environmental heterogeneity over short geographical distances. Such steep environmental gradients can induce ecological divergence. Lowland rainforests of the Guiana Shield are characterized by sharp, short-distance environmental variations related to topography and soil characteristics (from waterlogged bottomlands on hydromorphic soils to well-drained terra firme on ferralitic soils). Continuous plant populations distributed along such gradients are an interesting system to study intrapopulation divergence at highly local scales. This study tested (1) whether conspecific populations growing in different habitats diverge at functional traits, and (2) whether they diverge in the same way as congeneric species having different habitat preferences. Phenotypic differentiation was studied within continuous populations occupying different habitats for two congeneric, sympatric, and ecologically divergent tree species (Eperua falcata and E. grandiflora, Fabaceae). Over 3000 seeds collected from three habitats were germinated and grown in a common garden experiment, and 23 morphological, biomass, resource allocation and physiological traits were measured. In both species, seedling populations native of different habitats displayed phenotypic divergence for several traits (including seedling growth, biomass allocation, leaf chemistry, photosynthesis and carbon isotope composition). This may occur through heritable genetic variation or other maternally inherited effects. For a sub-set of traits, the intraspecific divergence associated with environmental variation coincided with interspecific divergence. The results indicate that mother trees from different habitats transmit divergent trait values to their progeny, and suggest that local environmental variation selects for different trait optima even at a very local spatial scale. Traits for which differentiation within species follows the same pattern as differentiation between species indicate that the same ecological processes underlie intra- and interspecific variation.
ISSN: 0305-7364

hal-01032430
https://hal.archives-ouvertes.fr/hal-01032430
DOI : 10.1093/aob/mct176

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
ISSN: 0927-7757

hal-00360381
https://hal.archives-ouvertes.fr/hal-00360381
DOI : 10.1016/j.colsurfa.2007.10.002

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
This paper examines the thermal properties of cement composites reinforced with vegetable bagasse fibres (1.5% and 3% wrtc). Thermal properties have been correlated to macroscopic density and porosity in order to estimate thermal conductivity of fibres using a calculation inspired from the Maxwell-Eucken modelling. Experimental investigations reveal that adding retified bagasse fibres reduces composites thermal conductivity and yields a weaker specific heat in comparison with composites made with alkaline bagasse fibres. Moreover, the more the fibres, the lighter the specimen; lower its thermal conductivity and lower its specific heat. Thermal conductivity of alkaline fibres is lower than retified fibres one.
ISSN: 1359-835X

hal-00809831
https://hal.univ-antilles.fr/hal-00809831
DOI : 10.1016/j.compositesa.2010.01.002

Résumé : Cette thèse a pour objet l'étude de la contrôlabilité à zéro de systèmes d'équations aux dérivées partielles paraboliques, que l'on rencontre en physique, chimie ou en biologie. En chimie ou en biologie, ces systèmes modélisent l'évolution au cours du temps d'une concentration chimique ou de la densité d'une population (de bactéries, de cellules). Le but de la contrôlabilité à zéro est d'amener la solution du système à l'état nul à un temps donné T, en agissant sur le système à l'aide d'un contrôle. Nous recherchons donc un contrôle, de norme minimale, tel que la solution associée y vérifie y(T)=O dans le domaine Omega considéré. Les problèmes de contrôlabilité à zéro considérés dans cette thèse sont de trois types. Dans un premier temps, nous nous intéressons à la contrôlabilité à zéro avec un nombre fini de contraintes sur la dérivée normale de l'état, pour l'équation de la chaleur semi-linéaire. Puis, nous analysons la contrôlabilité simultanée à zéro avec contrainte sur le contrôle, pour un système linéaire de deux équations paraboliques couplées. Notre dernière étude concerne la contrôlabilité à zéro d'un système non linéaire de deux équations paraboliques couplées. Nous abordons ces problèmes de contrôlabilité principalement à l'aide d'inégalités de Carleman. En effet, l'étude des problèmes de contrôlabilité à zéro, et plus généralement de contrôlabilité exacte, peut se ramener à l'établissement d'inégalités d'observabilité pour le problème adjoint, conséquences d'inégalités de Carleman. Nous construisons le contrôle optimal en utilisant la méthode variationnelle et nous le caractérisons par un système d'optimalité
This thesis is devoted to the study of the null controllability of systems of parabolic partial differential equations, which we meet in physics, chemistry or in biology. In chemistry or in biology, the se systems model the evolution in time of a chemical concentration or the density of a population (of bacteria, cells). The aim of nu Il controllability is to lead the solution of the system to zero in a given time T, by acting on the system with a control. Thus we are looking for a control, of minimal norm, such as the associated solution y satisfies y(T)=O in the domain Omega under concern. We consider three types of null controllability problems in this thesis. At first, we are interested in the null controllability with afinite number of constraints on the normal derivative of the state, for the serni-Iinear heat equation. Then, we analyze the simultaneous null controllability with constraint on the control, for a linear system of two coupled parabolic equations. Our last study deals with the null controllability ofa non linear system oftwo coupled parabolic equations. We approach these controllability problems mainly by means of Carleman's inequalities. Indeed, the study of null controllability problems, and more generally exact controllability problems, is equivalent to obtain observability inequalities for the adjoint problem, consequences of Carleman's inequalities. We build the optimal controlusing the variationnal method and we characterize it by an optimality system

http://www.theses.fr/2013AGUY0609/document

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Transport of liquid and gaseous hydrocarbons through focused fluid flow systems is a widespread process in continental margins and sedimentary basins, which is gaining increased attention in the assessment of geohazards, environment conservation, and securing fossil energy resources. Studying the abundance, distribution and drivers for this process is crucial for understanding its role in 1) the dynamics of gas hydrate accumulation and destabilization, 2) submarine slope stability and related tsunamis, 3) the plethora of chemosynthetic benthic ecosystems that develop in deep seep sites, and 4) the input of greenhouse gases (e.g. methane) into the ocean/atmosphere system, which may influence the atmospheric carbon budget and Earth's paleo- and present climate. New ocean exploration tools provide ever more data and improve our understanding of these systems. However, the subject still suffers from a lack of interdisciplinary knowledge dissemination. The ongoing international debate about the timing and the processes that control fluid expulsion in sedimentary basins is fuelled by their implications for structural and petroleum geology. Because fluids expelled at cold seeps originate at depth they represent open windows into the underlying petroleum systems and are valuable indicators for the reservoir systems. They may also help in deciphering past and predicting future climate change because worldwide release of large amounts of fluids may have an impact on the chemistry of the ocean and atmosphere.
ISSN: 0025-3227

hal-00772472
https://hal.archives-ouvertes.fr/hal-00772472
DOI : 10.1016/j.margeo.2012.10.012

Éditeur(s) : HAL CCSD American Chemical Society
Résumé : Absolute Mα and Mβ X-ray intensities were measured for the elements Pt, Au, Pb, U, and Th by electron impact for energies ranging from 6 to 38 keV. Experimental data were obtained by measuring the X-ray intensity emitted from bulk samples with an electron microprobe using high-resolution wavelength-dispersive spectrometers. Recorded X-ray intensities were converted into absolute X-ray yields by evaluation of the detector efficiency and then compared with X-ray intensities calculated by means of Monte Carlo simulations. Simulated Mα and Mβ X-ray intensities were found to be in good agreement with the measurements, allowing their use in standardless quantification methods. A procedure and a software program were developed to accurately obtain virtual standard values. Standardless quantifications of Pb and U were tested on standards of PbS, PbTe, PbCl2, vanadinite, and UO2.
ISSN: 0003-2700

hal-01217495
https://hal.archives-ouvertes.fr/hal-01217495
DOI : 10.1021/acs.analchem.5b01443

Résumé : Industrial potentialities related to biotechnology of microalgae are examined, highlighting a wide spectrum of applications which concern principally nutrition, health, environment and energy. The french situation of research on microalgae, especially at Ifremer, is assessed, showing that the main axis are fine chemistry, aquaculture, environment, bio-process engineering. It covers the majority of the applications, but leaves in shade certain important aspects such as human food and CO2 fixation. Concerning the general approach, some significant improvements can be expected from a more accurate control of bacteriological and genetic quality of cultures. About the industrial aspects, a national initiative seems in progress. The variety of potential applications together with strategic character of some of them (health, food), justify that research in relation with concerned fields be structured, and even intensified, in order to reinforce national position, and give extend to future developments.
Les potentialités industrielles attachées à la biotechnologie des microalgues sont inventoriées, faisant apparaître un large spectre d'applications touchant principalement l'alimentation, la santé, l'environnement et l'énergie. L'état en France, et à l'IFREMER en particulier, de la recherche touchant aux microalgues qui est dressé montre que les axes principaux sont orientés vers la chimie fine, l'aquaculture, l'environnement, le génie des procédés de production. Ceci couvre l'essentiel des applications, mais laisse cependant dans l'ombre certains aspects importants comme l'alimentation humaine, et l'épuration du C02- Sur le plan de la démarche, des progrès sensibles sont à attendre d'un contrôle plus rigoureux de la qualité bactériologique et génétique des cultures. Sur le plan industriel, une initiative nationale semble en cours. La variété des applications potentielles, et le caractère stratégique de certaines (santé, alimentation), justifient que la recherche dans les domaines concernés soit structurée, voire intensifiée, afin de renforcer la position nationale, et de donner de l'ampleur aux développements futurs.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1997/rapport-1092.pdf
http://archimer.ifremer.fr/doc/00000/1092/

Éditeur(s) : HAL CCSD RSC Publishing
Résumé : International audience
Abstract View references (36)The size or alkyl chain length of cationic surfactants can be used to tailor both the pore morphology and the functionality or oxidation state of cobalt in silica materials. This work shows for the first time that these two mechanisms are interconnected. Cobalt oxide silica materials, with the same cobalt loading (Co:Si = 1:4), were prepared using an acid catalysed sol-gel method where the cobalt/surfactant ratio was systematically varied. The alkyl chain length of the cationic surfactant was also varied from 2 to 12 by using tetraethyl (C2-AB) ammonium bromide, and triethyl hexyl (C6-AB) and dodecyl trimethyl (C12-AB) ammonium bromides as the templating agents. Initial addition of C2-AB, C6-AB or C12-AB enhanced the oxidation of cobalt to cobalt (ii,iii) oxide in the xerogels. However, as more surfactant is added the enhancement effect is reversed and the cobalt (ii,iii) oxide content of the sample begins to decline. The point at which this transition occurs is a function of the alkyl chain length of the surfactant, with a longer chain indicating an earlier transition. Pore morphology was influenced in a similar fashion with the longer alkyl chain C12-AB surfactant undergoing an earlier transition (i.e. at lower concentrations) towards mesoporosity, than either of the smaller C2-AB and C6-AB surfactants. In both mechanisms it was the increased propensity of the C12-AB surfactant to aggregate (given its larger size and lower solubility) that was the controlling factor. This journal is © the Partner Organisations 2014.
EISSN: 2046-2069

hal-01683205
https://hal.univ-antilles.fr/hal-01683205
DOI : 10.1039/c4ra05934d