Biodisponibilité du pentachlorophénol durant son transport en milieux poreux saturés

Le pentachlorophénol -- La disponibilité chimique -- La biodispobibilité pharmacologique -- La biodisponibilité environnementale -- Présentation générale des travaux -- Approche conceptuelle de la biodispobibilité -- Définition de la biodisponibilité -- Hypothèse de recherche et objectifs -- Development of a method to estimate the mass and toxic bioavailabilities of pentachlorophenol during its transport throughy saturated porous media -- Quantifiying mass and toxic bioavailability rates of pentachlorophenol during transport through saturated posous media -- Effec of biomass growth on the rates of mass and toxic bioavailability during continuous transport of pentachlorophenol through saturated porous media

Enzyme shielding in a soft organo-silica layer – pharma/biopharma applications

Enzymes, or biocatalysts, are specialty proteins. Like antibodies to antigens, enzymes exhibit remarkable specificity for their substrate and naturally facilitate many chemical conversions. However, the use of enzymes in the biotech industry ($2.3bn) is strongly limited by the fact that enzymes are highly sensitive like most proteins and usually not fitted to in vivo and process conditions. Many expensive genetically engineered or biosourced enzymes show remarkable properties but need to be made more robust for deployment in the health industry. We have developed a unique procedure to fit enzymes to in vivo and process conditions. The process is initiated by immobilizing any enzyme or cocktail of enzymes onto safe silica particles (Step 1 on Figure 1) and protect them by growing a nano-structured shield on the outer surface of the particle (Step 2 on Figure 1). This formulation of enzymes provides them with remarkable resistance to in vivo and process conditions, such as acidity, temperature, presence of chaotropic agents, proteases, solvents, etc. Please click Additional Files below to see the full abstract

Rosetta-Philae RF Link, from Separation to Hibernation

The Rosetta spacecraft reached the vicinity of the comet 67P/Churyumov-Gerasimenko in 2014 and released the lander Philae for an in-situ analysis through ten scientific instruments. The analysis of the lander RF link telemetry reveals major information on the lander behavior and environment during the 50-hour mission on the comet

Traçage spatial et temporel des eaux souterraines dans les hydrosystèmes karstiques par les matières organiques dissoutes (expérimentation et application sur les sites du Laboratoire Souterrain à Bas Bruit (LSBB) de Rustrel Pays d'Apt et de Fontaine de Vaucluse)

Le principal objectif de ce travail est le développement, l'application et la validation de nouveaux traceurs hydrogéologiques sur la base de signatures spectrales spécifiques des matières organiques dissoutes (MOD) et du suivi de leur évolution dans les hydrosystèmes karstiques méditerranéens. Pour cela, de nombreuses analyses hydrodynamiques et hydrochimiques ont été réalisées, et plusieurs méthodes de caractérisation de la MOD ont été utilisées. Le travail s'est alors fondé sur l'étude de différents niveaux du bassin expérimental de la Fontaine de Vaucluse (sol, épikarst et zone non saturée), grâce à un accès privilégié rendu possible par le Laboratoire Souterrain à Bas Bruit de Rustrel-Pays d'Apt (Vaucluse, France). Un bon traceur hydrogéologique requiert des caractéristiques particulières (solubilité dans l'eau, stabilité, tendance faible à l'adsorption, limite de détection faible et des variations bien identifiables). Les composés organiques correspondant le mieux à ces critères sont des substances dérivées de la décomposition de la lignine. Leurs différentes caractéristiques et leurs faibles concentrations dans l'hydrosystème poussent à utiliser des modes de détection suffisamment sensibles tels que la spectrométrie de fluorescence et la Résonance Paramagnétique Électronique (RPE). L application conjointe des analyses en RPE et en spectrofluorimétrie sur les lixiviats de sols et les eaux souterraines du LSBB permet de proposer deux protocoles de traçages hydrogéologiques. Le premier concerne la détermination des zones superficielles de sol appartenant au bassin d alimentation des écoulements suivis. Le second, s'appuyant notamment sur l'évolution et la dynamique des MOD dans l'hydrosystème, correspond au développement de traceurs quantitatifs du temps de transit de l'eau pouvant s appliquer de manière évènementielle par le marquage d une période particulière de leur variation, ou en continu permettant ainsi le suivi des variations du temps de transit. Enfin, le rapprochement des résultats obtenus par ces nouveaux traceurs organiques avec ceux d'un traceur isotopique (l'oxygène 18) a permis de tester la validité des calculs du temps de transit, mais aussi de démontrer leur complémentaritéThe aim of this study is to develop, apply and validate new hydrogeological tracers, based on specific spectral fingerprints of Dissolved Organic Matter (DOM), and a monitoring of their evolution in Mediterranean karstic hydrosystems. Many hydrodynamic and hydrochemical analyses were made, and several DOM characterization methods were used. The basis of this work is therefore the study of different levels of Fontaine de Vaucluse experimental basin (soil, epikarst and unsaturated zone), thanks to a privileged access : the Low-Noise Underground Laboratory of Rustrel - Pays d Apt (Vaucluse, France). Good hydrogeological tracers require specific characteristics (water solubility, stability, a low tendency to adsorption, a low detection limit and identifiable variations). Organic compounds, corresponding to these criterions at best, are lignin-derived compounds. Their different characteristics and their low concentrations in the hydrosystem drive us to use sensitive enough detection methods, such as fluorescence spectrometry and Electronic Paramagnetic Resonance (EPR). Linked application of EPR and spectrofluorimetric analyses of leachate soil and LSBB groundwater allow to develop two hydrogeological tracing protocols. The first one concerns the determination of upper soil zone, which belongs to monitoring flow catchment area. The second one, using the evolution and the dynamics of DOM in the hydrosystem, corresponds to the development of transit time qualitative tracers, which apply either in an event-driven way by the marking of specific period of their variations, or continuously allowing the monitoring of transit time variations. Finally, the comparison between the results obtained by these new organic tracers and by an isotopic tracer (18 Oxygen) allows to validate transit time calculations and prove their complementarityAVIGNON-Bib. numérique (840079901) / SudocSudocFranceF

Organic matter as a potential complementary tool for δ 18 O data interpretation in heterogeneous aquifers†

International audienceEvaluating transit time by using δ18O seasonal variation is often difficult in a Mediterranean context due to the erratic rainfall signature added to the complexity of flow mixing. The present study aims to show that using organic matter can improve interpretations of the δ18O signal. The natural fluorescence of organic compounds and dissolved organic carbon (DOC) data were recorded in the underground low-noise laboratory, located within the catchment area of the Fontaine de Vaucluse karstic system, over a four-year period. By combining both total fluorescence and DOC, a systematic seasonal variation is observed only due to soil–water interaction. Therefore, when the recharge rate is enough at the time of the season concerned, a new specific seasonal tracer, independent of rainfall signature, is available. Besides, the DOC concentration is a tracer of rapid infiltration with short transit time associated with high DOC concentration, while long transit time waters are characterised by a low DOC concentration. Then this can also shed light on such a mixing, recent/old waters. A more sensitive interpretation of δ18O variations is then possible: if the rainfall amount and δ18O follow a seasonal trend, both tracers may be used in the same way; if the recharge is discontinuous due to discontinuous rainfall regime, δ18O tracing alone is usable; in case of erratic or smooth rainfall signature during the homogeneous rainy period, fluorescent organic matter tracing alone is then usable

Pulsed electric field induced redistribution of fluorescent compounds from water-extractable soil organic matter

International audienceModifications of bacterial activities are observed when continuous electric current is applied in soil for soil remediation purposes (electrokinetic). In this study we found a significant increase of 330% of the total heterotrophic culturable bacteria 2 d after soil samples had been submitted to pulsed electric field (PEF) treatment (E not, vert, similar 4 KV/cm, τ not, vert, similar 5 ms, 3 pulses) resulting from pulsed electric current injections. We hypothesized that this result was caused by qualitative and/or quantitative modifications of the dissolved organic matter and tested this using a γ-sterilized model soil. The incidence of electrical parameters (electric field intensity and pulse duration) on the water-extractable organic matter was analysed using two types of experimental set-ups for current injection. These experimental set-ups exhibited different volume, physical state (liquid, solid) of the soil samples and different electrical conditions. Total organic carbon content and fluorescence signature (excitation-emission matrix, EEM) were monitored for all samples. A 67% decrease in the ratio between higher and lower molecular weight fluorescent compounds was observed, indicating a new distribution of the fluorescent compounds into the dissolved organic matter following PEF treatment