Narrateur, personnage et lecteur. Pragmatique des subjectivèmes relationnels, des points de vue énonciatifs et de leur dialogisme

in Cahiers de Narratologie (2013)

Les instances internes au récit que sont le narrateur, le personnage et le lecteur virtuel entretiennent des relations, principalement idéologiques et affectives, que l’on peut décrire d’après une ... [more ▼]

Les instances internes au récit que sont le narrateur, le personnage et le lecteur virtuel entretiennent des relations, principalement idéologiques et affectives, que l’on peut décrire d’après une approche pragma-énonciative et rhétorique. Nous proposons une modélisation du système intra-relationnel du récit et une réflexion sur plusieurs problématiques que pose l’analyse de ces relations : le repérage des subjectivèmes relationnels, l’identification de leurs effets pragmatiques, leur assemblage en un point de vue émanant d’un sujet énonciateur particulier, les différentes articulations possibles entre les points de vue du narrateur et du personnage et leurs effets pragmatiques. D’après cette perspective nous proposons une nouvelle analyse et interprétation du récit La Femme de Gilles de Madeleine Bourdouxhe. [less ▲]

Reproductive impacts of tributyltin (TBT) and triphenyltin (TPT) in the hermaphroditic freshwater gastropod Lymnaea stagnalis

in Environmental Toxicology & Chemistry (2013), 32(7), 1552-1560

Tributyltin (TBT) and triphenyltin (TPT) are emblematic endocrine disruptors, which have been mostly studied in gonochoric prosobranchs. Although both compounds can simultaneously occur in the environment ... [more ▼]

Tributyltin (TBT) and triphenyltin (TPT) are emblematic endocrine disruptors, which have been mostly studied in gonochoric prosobranchs. Although both compounds can simultaneously occur in the environment, they have mainly been tested separately for their effects on snail reproduction. Because large discrepancies in experimental conditions occurred in these tests, the present study aimed at comparing the relative toxicity of TBT and TPT under similar laboratory conditions in the 0–600 ng Sn/L range. Tests were performed on the simultaneous hermaphrodite Lymnaea stagnalis, a freshwater snail in which effects of TPT were unknown. Survival, shell length and reproduction were monitored in a 21d semi-static test. Frequency of abnormal eggs was assessed as an additional endpoint. TPT hampered survival while TBT did not. Major effects on shell solidity and reproduction were observed for both compounds, reproductive outputs being more severely hampered by TBT than by TPT. Considering the frequency of abnormal eggs allowed increasing test sensitivity, since snail responses to TBT could be detected at concentrations as low as 19 ng Sn/L. However, the putative mode of action of the two compounds could not be deduced from the structure of the molecules or from the response of apical endpoints. Sensitivity of L. stagnalis to TBT and TPT was compared to the sensitivity of prosobranch molluscs with different habitats and different reproductive strategies. [less ▲]

Chemical imaging of small molecules from simple to complex matrices: Quantitative approches based on Surface Enhanced Raman scattering

Conference (2013, July)

Surface Enhanced Raman scattering (SERS) allows to dramatically exalt the Raman diffusion of molecules absorbed or very closed to rough metallic surfaces while keeping their structural information. SERS ... [more ▼]

Surface Enhanced Raman scattering (SERS) allows to dramatically exalt the Raman diffusion of molecules absorbed or very closed to rough metallic surfaces while keeping their structural information. SERS chemical imaging, presenting a high specificity and sensibility, allows acquiring a visual representation of samples combining spectral and spatial measurements. This technique could become a powerful tool in pharmaceutical and biological analysis enabling to identify and quantify molecules thanks to chemometric evaluation while looking at their distribution or their interactions. In this context, SERS chemical imaging is investigated in detection or quantitative determination of molecules in pharmaceutical and biological matrices. The feasibility of making quantitative measurements using SERS is evaluated on small target molecules models such as 4-aminophenol and lactate. Firstly, a SERS method to quantify 4-aminophenol which is the primary impurity of acetaminophen coming from its degradation during the storage or from its synthesis was developed on a real pharmaceutical formulation. The standard addition method was selected as calibration method in order to take into account the matrix effect coming from the different components of the latter. Despite the well-known stability and repeatability problems of SERS, the method was thoroughly validated by means of accuracy profiles as decision tool. Moreover, this validation methodology allowed to define a first estimation of the real analytical performance of the technique. Secondly, the detection of lactate, which is a critical metabolite implicated in several metabolic disorders, was successfully tested in the physiological concentration in a simple matrix. Preliminary results for the determination of this metabolic biomarker were also very promising allowing to consider more complex matrices. Based on these results, SERS chemical imaging was implemented to detect 4-aminophenol in a pharmaceutical tablet formerly pulverised by a SERS substrate. Through this imaging technique, it was not only possible to detect the presence of the impurity at the limit of specification of 0.1% (w/w) but it was also possible to differentiate tablets comprising different concentrations of the latter. These promising results represent the first step towards quantitative measurements using SERS chemical imaging. [less ▲]

Models and prospects for a sustainable suburban transition.

in Re-engineering the city 2020-2050: Modelling Sustainable Urban Transition Dynamics (2013, July)

This paper addresses the challenges, transformations and conditions of a sustainable suburban transition. Two powerful levers are used: (1) urban form, which is considered in addition to the individual ... [more ▼]

This paper addresses the challenges, transformations and conditions of a sustainable suburban transition. Two powerful levers are used: (1) urban form, which is considered in addition to the individual building scale, and (2) mobility, because sprawl spatially separates activities, resulting in an increase in travel distances and energy used in transportation. Two main indicators (the heating needs of different types of suburban forms and a commute performance index) are developed and discussed. Three scenarios focused on the evolution of the existing building stock are modelled and assessed (the retrofitting of existing neighbourhoods, an increase in the built density and demolition / reconstruction) to answer two main questions: "how to intervene in suburban areas?" and" where to intervene? ". These main results focused on energy efficiency are then studied in a larger framework to highlight the opportunities, limitations, constraints and feasibility of each strategy. Concrete prospects and guidelines for policy makers are finally proposed to operationalize a "sustainable suburban renewal". These findings show that, beyond the traditional polarization of the debates on energy efficiency of our built environment between the “compact city” and the “sprawled city”, a new pragmatic paradigm, focused on the transition of suburban areas by densification, can make suburban areas evolve towards more sustainability. [less ▲]

Evaluation of the residual solvent content of counterfeit tablets and capsules

in Journal of Pharmaceutical & Biomedical Analysis (2013), 81-82

A group of counterfeit samples of Viagra® and Cialis® were screened for their residual solvent content and compared to the content of the genuine products. It was observed that all counterfeit samples had ... [more ▼]

A group of counterfeit samples of Viagra® and Cialis® were screened for their residual solvent content and compared to the content of the genuine products. It was observed that all counterfeit samples had higher residual solvent contents compared to the genuine products. A more diverse range of residual solvents was found as well as higher concentrations. In general these concentrations did not exceed the international imposed maximum limits. Only in a few samples the limits were exceeded. A Projection Pursuit analysis revealed clusters of samples with similar residual solvent content, possibly enabling some future perspectives in forensic research. [less ▲]

Bacillus subtilis as a tool for screening soil metagenomic libraries for antimicrobial activities

in Journal of Microbiology and Biotechnology (2013), 23(6), 850-855

L'éruption de la fin. Emotion, mort et conscience dans la préface aux Damnés de la terre

Conference (2013, June 26)

ORF9p: a new player in the Varicella-Zoster Virus egress

Doctoral thesis (2013)

Contribution to the study of the resistance to drying of Pseudomonas fluorescens

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013)

The objective of this thesis is to study the resistance to drying of Pseudomonas fluorescens. Freeze-drying is the most suitable method for drying P. fluorescens. However, freeze-drying induced loss of ... [more ▼]

The objective of this thesis is to study the resistance to drying of Pseudomonas fluorescens. Freeze-drying is the most suitable method for drying P. fluorescens. However, freeze-drying induced loss of cell viability. This loss of viability is mainly due to membrane rupture, temperature and oxidation of fatty acids, membrane proteins and glutathione. For this purpose, the use of protective compounds during freeze-drying has allowed us to obtain a powder having a high viability. We then studied the impact of these protective compounds, oxygen and storage temperature on the viability of P. fluorescens during storage. Analyses of fatty acids, proteins, glutathione and the study of membrane integrity during the various manufacturing processes and storage have established a link between the degree of oxidation and cell death. The results of flow cytometry showed that the freeze-drying longer affects the viability of P. fluorescens rather than storage. We have increased the yield of the production in bioreactor of P. fluorescens and time of culture was halved. [less ▲]

Impacts and mechanisms of action of endocrine disrupting chemicals on the hermaphroditic freshwater gastropod Lymnaea stagnalis (Linnaeus, 1758)

Doctoral thesis (2013)

Adverse impacts exerted by molecules called endocrine disruptors on reproduction have been extensively described in vertebrates. However, endocrine-disrupting chemicals might alter reproduction of ... [more ▼]

Adverse impacts exerted by molecules called endocrine disruptors on reproduction have been extensively described in vertebrates. However, endocrine-disrupting chemicals might alter reproduction of invertebrate species, at lower concentrations or through different modes of action, with consequences on population growth and stability. Among invertebrates, molluscs have been shown to be very sensitive to endocrine disruptors and were therefore proposed as model species for the development of OECD guideline for the testing and the assessment of reprotoxic effect of chemicals, including EDCs. The hermaphrodite gastropod species Lymnaea stagnalis is a candidate species for the development of such guidelines. In this context, the aim of this thesis is to provide a better understanding of the impacts and the mechanisms of action of endocrine disrupting chemicals on the reproduction of L. stagnalis. The chemicals tested in the present work were chosen based on their interactions with the endocrine system of vertebrates. Testosterone is the natural ligand of the androgen receptor in vertebrates. Three different molecules were selected for their antagonism of the androgen receptor in vertebrates: the synthetic steroid cyproterone acetate, the dicarbamide fungicide vinclozolin and the organophosphate insecticide fenitrothion. Chlordecone is an organochlorinated pesticide, which binds oestrogen receptors in vertebrates. Finally, two organotin compounds, triphenyltin and tributyltin, are able to induce the development of imposex, imposition of male sex organs in females, in gonochoric gastropod molluscs. Results of the present work are divided into two main sections. Firstly, we investigated the impacts of the selected chemicals on the reproduction of L. stagnalis. Our results displayed that TBT, TPT, and chlordecone are able to induce adverse impacts on the reproduction of L. stagnalis through a reduction of the cumulative number of eggs and clutches produced per individual. The assessment of the quality of eggs produced showed that exposure to the chemicals, except TPT, increases the frequency of abnormal eggs laid. The impacts on egg quality were observed at lower concentrations than those affecting the classical reproductive endpoints assessed in reprotoxicity tests in this species. Our results highlight that the implementation of egg quality as an endpoint should increase the sensitivity of the reprotoxicity test with L. stagnalis. The second section of results aims at providing new insights on the mechanisms of action of putative endocrine disruptors in L. stagnalis. Results from chapter 3 and 4 allowed us to select chemical treatments (testosterone, tributyltin, cyproterone acetate, and chlordecone) that induced adverse effects, by interacting with the endocrine system, on the reproduction of L. stagnalis. In Chapter 5, we analysed endogenous concentrations of testosterone, in its free and esterified forms, in the reproductive organs of L. stagnalis. Exposure to waterborne testosterone has confirmed that molluscs can take up this steroid from environmental media and that a homeostatic regulation of endogenous concentrations occurs through the esterification of steroids to fatty acid esters. Moreover, our results support that testosterone is endogenously synthesised in L. stagnalis, as it has been suggested in other mollusc species. However, the impacts on the reproduction and the modifications of endogenous concentrations of testosterone reported in this thesis could not be associated. In chapter 6, proteomic experiments were used to identify proteins differently expressed in reproductive organs of L. stagnalis exposed to testosterone, tributyltin, cyproterone acetate, and chlordecone. Modifications in the expression of three proteins involved in L. stagnalis reproduction (i.e., ovipostatin, yolk ferritin and PIWI) could be associated with the alterations of reproductive endpoints reported in chapters 3 and 4, therefore suggesting possible endocrine disruption mechanisms. Altogether, the results obtained in the present work provide evidences of interactions between chemicals and the endocrine system of this hermaphrodite species. Moreover, the additional sensitive reproductive endpoints described in this thesis (i.e., egg quality) as well as the identification of particular proteins (i.e., ovipostatin, yolk ferritin and PIWI) and their differential expression patterns following chemical exposure, provide reliable tools to screen potency of toxicants to be endocrine disruptors in a partial life cycle test on the freshwater gastropod Lymnaea stagnalis. [less ▲]