Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Tilt fluctuations can potentially reflect the response of hydrosystems to important rainfall. In this context, long baseline tiltmeters have been installed in an underground tunnel penetrating the Fontaine de Vaucluse karst to study the medium deformation related to solicitations exerted by water infiltrating the hydrosystem. The instruments monitor the tilt as well as its spatial variation. Northward tilts reaching a 1 μrad amplitude are observed consecutively to rainfalls. The tilt amplitude is highly correlated with the Fontaine de Vaucluse outlet flow fluctuations. The measured tilt signal is also relatively homogeneous over a 150 m length. Different types of structure likely to produce such observations are tested in order to identify their location with respect to the tiltmeters, their dimension as well as the amount of water level variation in the structure. Following rainfalls, the infiltration of water modifies the pore pressure, inducing a medium deformation. The hypothesis of an homogeneous surface loading on the Vaucluse plateau is first refuted since the related tilt is much lower than the one measured. The water supplied by rainfalls has to accumulate in discontinuities in order to generate a higher tilt. So, the deformation related to a pressure exerted on a fracture filled by water is assessed. A first study reveals the interest of the tilt homogeneity information that constrains strongly the fracture properties. Thus, the fracture must be located at a distance more than a few hundreds metres from the tiltmeters in order to produce a tilt homogeneous in space. If the fracture is initially dry, it must also be filled on a height higher than 150 m consecutive to a rainfall in order to generate a tilt amplitude in the same magnitude as the one measured. Then, we explore the influence of water level variations on the tilt produced by a fracture located at the interface between the saturated and unsaturated zones, which are thereby permanently flooded. Since several parameters of that model satisfactorily explain the field observations, we discuss how simultaneous geodetical observations could provide complementary information that would further constrain the geometry of the structure at the origin of the medium deformation.
ISSN: 0956-540X

insu-01408482
https://hal-insu.archives-ouvertes.fr/insu-01408482
https://hal-insu.archives-ouvertes.fr/insu-01408482/document
https://hal-insu.archives-ouvertes.fr/insu-01408482/file/Lesparre-2017.pdf
DOI : 10.1093/gji/ggw446

Éditeur(s) : HAL CCSD
Résumé : International audience
Lecture Notes in Statistics

hal-00690143
https://hal.archives-ouvertes.fr/hal-00690143

Éditeur(s) : HAL CCSD
Résumé : International audience
A fiber interferometer interfaced to 3 geo-mechanical elements is presented for applications in geophysics. The fiber sensor is based on an extrinsic fiber Fabry-Perot interferometer (EFFPI) which incorporates a modulation scheme to lock the interferometer at quadrature and to enable displacement measurements below a quarter of the interrogating wavelength. It operates over a relatively large frequency dynamic of ~500000 with a precision better than 2 nm. The fiber interferometer is next interfaced to a differential hydrostatic long baseline inclinometer, a 3-axis borehole tiltmeter and a single-axis seismometer, respectively. Results obtained demonstrate that the fiber interferometrically-interrogated instruments exhibit performances equivalent to or even surpassing those of the reference instruments employed for comparison during their deployment to an underground test site since March 2012. Keywords—modulation-based extrinsic fiber Fabry-Perot interferometer; fiber optique hydrostatic inclinometer; fiber optique borehole tiltmeter; fiber optique seismometer
IEEE SENSORS 2015
Busan, South Korea

hal-01265963
https://hal.archives-ouvertes.fr/hal-01265963
https://hal.archives-ouvertes.fr/hal-01265963/document
https://hal.archives-ouvertes.fr/hal-01265963/file/HCS3.pdf
DOI : 10.1109/ICSENS.2015.7370316

Éditeur(s) : HAL CCSD
Résumé : National audience
Actes du 20ième colloque du GRETSI (2005)
Louvain-la-Neuve, Belgium

hal-00605242
https://hal.archives-ouvertes.fr/hal-00605242

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Diagnosis of toxoplasmic encephalitis (TE) in patients with AIDS is not straightforward because clinicians rely initially on an empiric diagnosis based on clinical and radiographic improvement to specific anti-Toxoplasma gondii therapy. There is therefore a need for biological tools to improve the diagnosis of TE, especially in tropical areas where this diagnosis is likely to be underestimated. The use of PCR testing in blood samples for the diagnosis of TE has been limited by its poor sensitivity in the studies conducted in Europe. In tropical South America, the results of PCR sensitivity in blood samples were controversial. Considering that T. gondii strains from tropical South America have substantial genetic and pathogenic differences with those from USA and Europe, it is therefore important to re-evaluate the performance of the PCR assay in blood samples for the diagnosis of TE in AIDS patients from this region. Our results showed that the only interest of PCR would be in the most severe forms of TE with altered consciousness because PCR is more likely to be positive. We also provided important genotyping data on T. gondii strains isolated in human cases of toxoplasmosis in the Caribbean and in South America.
ISSN: 1935-2727

hal-01503761
https://hal-unilim.archives-ouvertes.fr/hal-01503761
https://hal-unilim.archives-ouvertes.fr/hal-01503761/document
https://hal-unilim.archives-ouvertes.fr/hal-01503761/file/journal.pntd.0004790.pdf
DOI : 10.1371/journal.pntd.0004790

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : International audience
ISSN: 1631-0691

hal-01083754
https://hal-agroparistech.archives-ouvertes.fr/hal-01083754
DOI : 10.1016/j.crvi.2009.01.006

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Sensitive instruments like strainmeters and tiltmeters are necessary for measuring slowly varying low amplitude Earth deformations. Nonetheless, laser and fibre interferometers are particularly suitable for interrogating such instruments due to their extreme precision and accuracy. In this paper, a practical design of a simple pendulum borehole tiltmeter based on laser fibre interferometric displacement sensors is presented. A prototype instrument has been constructed using welded borosilicate with a pendulum length of 0.85 m resulting in a main resonance frequency of 0.6 Hz. By implementing three coplanar extrinsic fibre Fabry-Perot in-terferometric probes and appropriate signal filtering, our instrument provides tilt measurements that are insensitive to parasitic deformations caused by temperature and pressure variations. This prototype has been installed in an underground facility (Rustrel, France) where results show accurate measurements of Earth strains derived from Earth and ocean tides, local hydro-logic effects, as well as local and remote earthquakes. The large dynamic range and the high sensitivity of this tiltmeter render it an invaluable tool for numerous geophysical applications such as transient fault motion, volcanic strain and reservoir monitoring.
ISSN: 0956-540X

hal-01265967
https://hal.archives-ouvertes.fr/hal-01265967
https://hal.archives-ouvertes.fr/hal-01265967/document
https://hal.archives-ouvertes.fr/hal-01265967/file/HCS1.pdf
DOI : 10.1093/gji/ggv358

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
BACKGROUND & AIMS: Nutrients influence non-alcoholic fatty liver disease. Essential fatty acids deficiency promotes various syndromes, including hepatic steatosis, through increased de novo lipogenesis. The mechanisms underlying such increased lipogenic response remain unidentified. METHODS: We used wild type mice and mice lacking Liver X Receptors to perform a nutrigenomic study that aimed at examining the role of these transcription factors. RESULTS: We showed that, in the absence of Liver X Receptors, essential fatty acids deficiency does not promote steatosis. Consistent with this, Liver X Receptors are required for the elevated expression of genes involved in lipogenesis in response to essential fatty acids deficiency. CONCLUSIONS: This work identifies, for the first time, the central role of Liver X Receptors in steatosis induced by essential fatty acids deficiency.
ISSN: 0168-8278

inserm-00872314
http://www.hal.inserm.fr/inserm-00872314
DOI : 10.1016/j.jhep.2013.01.006
PUBMED : 23333450

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Liver X Receptors (LXRs) α and β and the Peroxisome Proliferator-Activated Receptor α (PPARα) are transcription factors that belong to class II nuclear receptors. They drive the expression of genes involved in hepatic lipid homeostasis and therefore are important targets for the prevention and treatment of nonalcoholic fatty liver disease (NAFLD). LXRs and PPARα are regulated by endogenous ligands, oxysterols and fatty acid derived molecules, respectively. In the liver, pharmacological activation of LXRs leads to the over-expression of genes involved in de novo lipogenesis, while PPARα is critical for fatty acid catabolism in nutrient deprivation. Even if these two nuclear receptors seemed to play opposite parts, recent studies have highlighted that PPARα also influence the expression of genes involved in fatty acids synthesis. In this study, we used pharmacological approaches and genetically engineered mice to investigate the cross-talk between LXRs and PPARα in the regulation of genes responsible for lipogenesis. We first investigated the effect of T0901317 and fenofibrate, two synthetic agonists of LXRs and PPARα, respectively. As expected, T0901317 and fenofibrate induce expression of genes involved LXR-dependent and PPARα-dependent lipogenic responses. Considering such overlapping effect, we then tested whether LXR agonist may influence PPARα driven response and vice versa. We show that the lack of PPARα does not influence the effects of T0901317 on lipogenic genes expression. However, PPARα deficiency prevents the up-regulation of genes involved in ω-hydroxylation that are induced by the LXR agonist. In addition, over-expression of lipogenic genes in response to fenofibrate is decreased in LXR knockout mice as well as the expression of PPARα target genes involved in fatty acid oxidation. Altogether, our work provides in vivo evidence for a central interconnection between nuclear receptors that drive hepatic lipid metabolism in response to oxysterol and fatty acids.
ISSN: 0300-9084

inserm-00872582
http://www.hal.inserm.fr/inserm-00872582
DOI : 10.1016/j.biochi.2012.09.028
PUBMED : 23063693

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
ISSN: 1433-8319

hal-01095295
https://hal-agroparistech.archives-ouvertes.fr/hal-01095295
DOI : 10.1007/s00606-010-0312-3

Éditeur(s) : HAL CCSD
Résumé : International audience
OBJECTIVES: Semen composition is influenced by HIV-1 infection, yet the impact of semen components on HIV infection of primary target cells has only been studied in samples from HIV-uninfected donors. DESIGN: We compared the effect of seminal plasma from chronically HIV-infected (SP+) versus uninfected donors (SP-) on HIV-1 infection of PBMCs and CD4+T cells. METHODS: Primary cells were infected with HIV-1 in the presence of SP+ or SP- and analyzed for infection level, metabolic activity, HIV receptor expression, proliferation and activation. SP+ and SP- were compared for infection-enhancing peptides, cytokines and prostaglandin E2 levels. RESULTS: SP- efficiently enhanced HIV-1 R5 infection of CD4+ T cells, whereas SP+ enhancing activity was significantly reduced. RANTES concentrations were elevated in SP+ relative to SP-, while the concentrations of infectivity-enhancing peptides (SEVI, SEM1, SEM2) were similar. CCR5 membrane expression levels were reduced on CD4+T cells shortly post-exposure to SP+ compared with SP- and correlated to R5-tropic HIV-1 infection levels, and CCR5 ligands' concentrations in semen. SP+ and SP- displayed similar enhancing activity on PBMC infection by X4-tropic HIV-1. Addition/depletion of RANTES from seminal plasmas modulated their effect on PBMC infection by R5-tropic HIV-1. CONCLUSIONS: Semen from HIV-infected donors exhibit a significantly reduced enhancing potential on CD4+ T cell infection by R5-tropic HIV-1 when compared with semen from uninfected donors. Our data indicate that elevated seminal concentrations of RANTES in HIV+ men can influence the ability of semen to enhance infection.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives 4.0 License, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. http://creativecommons.org/licenses/by-nc-nd/4.0
AIDS

hal-01274885
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01274885
DOI : 10.1097/QAD.0000000000001048
PUBMED : 26854806

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
We assessed the occurrence of algae in five species of tank-bromeliads found in contrasting environmental sites in a Neotropical, primary rainforest around the Nouragues Research Station, French Guiana. The distributions of both algal abundance and biomass were examined based on physical parameters, the morphological characteristics of bromeliad species and with regard to the structure of other aquatic microbial communities held in the tanks. Algae were retrieved in all of the bromeliad species with mean densities ranging from ∼10(2) to 10(4) cells/mL. Their biomass was positively correlated to light exposure and bacterial biomass. Algae represented a tiny component of the detrital food web in shaded bromeliads but accounted for up to 30 percent of the living microbial carbon in the tanks of Catopsis berteroniana, located in a highly exposed area. Thus, while nutrient supplies are believed to originate from wind-borne particles and trapped insects (i.e., allochtonous organic matter), our results indicate that primary producers (i.e., autochtonous organic matter) are present in this insectivorous bromeliad. Using a 24-h incubation of size-fractionated and manipulated samples from this plant, we evaluated the impact of mosquito foraging on algae, other microorganisms and rotifers. The prey assemblages were greatly altered by the predation of mosquito larvae. Grazing losses indicated that the dominant algal taxon, Bumilleriopsis sp., like protozoa and rotifers, is a significant part of the diet of mosquito larvae. We conclude that algae are a relevant functional community of the aquatic food web in C. berteroniana and might form the basis of a complementary non-detrital food web.
ISSN: 1932-6203

hal-00819161
https://hal.archives-ouvertes.fr/hal-00819161
https://hal.archives-ouvertes.fr/hal-00819161/document
https://hal.archives-ouvertes.fr/hal-00819161/file/Brouard2011_AreAlgae.pdf
DOI : 10.1371/journal.pone.0020129

Éditeur(s) : HAL CCSD
Résumé : International audience
Proceedings - 26th IEEE International Conference on Advanced Information Networking and Applications Workshops, WAINA 2012
Fukuoka, Japan

hal-00755765
https://hal.archives-ouvertes.fr/hal-00755765

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : Intraguild predation (IGP) is a type of biological interaction involving the killing and consuming of competing species that exploit similar and often limited resources. This phenomenon is widespread among a great variety of taxonomic groups and has already been reported for mosquito (Diptera: Culicidae) larvae. Moreover, the larvae of certain mosquito species of the tribe Sabethini have evolved modified mouthparts ending in rigid apical structures signaling their capacity to be effective intraguild predators. We assumed that IGP confers a selective advantage under severe competitive conditions by both providing an immediate energetic gain and reducing potential competition. Because potential competition is likely to increase with decreasing habitat size, we hypothesized that the proportion of species with modified mouthparts would increase in smaller aquatic habitats. We tested this hypothesis by examining the mosquito species naturally associated with phytotelmata of decreasing sizes in French Guiana. We show that the degree of specialization in mosquito-phytotelm associations is high, suggesting a long coevolutive process. Indeed, short-term interaction experiments confirmed that species with modified mouthparts are able to prey upon similarly-sized intraguild prey and are, thus, effective intraguild predators. In addition, these species are larger and associated with smaller phytotelmata than those with typical mouthparts. Moreover, below a certain threshold of phytotelm size, only species with modified mouthparts were present. These results show that IGP confers a selective advantage under severe competitive conditions and results from the coadaptation of mosquito species to their specific phytotelm habitat. The presence of functionally analogous structures in different mosquito genera also implies that IGP has emerged from convergent evolution in small phytotelmata.
ISSN: 0269-7653

hal-01603304
https://hal.archives-ouvertes.fr/hal-01603304
DOI : 10.1007/s10682-016-9862-3
PRODINRA : 405771

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
ISSN: 0029-8549

hal-00524665
https://hal.archives-ouvertes.fr/hal-00524665

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
According to the World Health Organization, around 20% of all cancers would be due to environmental factors. Among these factors, several chemicals are indeed well recognized carcinogens. The widespread contaminant benzo[a]pyrene (B[a]P), an often used model carcinogen of the polycyclic aromatic hydrocarbons' family, has been suggested to target most, if not all, cancer hallmarks described by Hanahan and Weinberg. It is classified as a group I carcinogen by the International Agency for Research on Cancer; however, the precise intracellular mechanisms underlying its carcinogenic properties remain yet to be thoroughly defined. Recently, the pH homeostasis, a well known regulator of carcinogenic processes, was suggested to be a key actor in both cell death and Warburg-like metabolic reprogramming induced upon B[a]P exposure. The present review will highlight those data with the aim of favoring research on the role of H + dynamics in environmental carcinogenesis.
ISSN: 1044-579X

hal-01531077
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01531077
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01531077/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01531077/file/Hardonniere%20et%20al.%20-%20Environmental%20carcinogenesis%20and%20pH%20homeostasis%20n.pdf
DOI : 10.1016/j.semcancer.2017.01.001

Éditeur(s) : HAL CCSD Endocrine Society
Résumé : International audience
Transcriptional regulation by the estrogen receptor-alpha(ER) has been investigated mainly in breast cancer cell lines, but estrogens such as 17 beta-estradiol (E2) exert numerous extrareproductive effects, particularly in the liver, where E2 exhibits both protective metabolic and deleterious thrombotic actions. To analyze the direct and early transcriptional effects of estrogens in the liver, we determined the E2-sensitive transcriptome and ER cistrome in mice after acute administration of E2 or placebo. These analyses revealed the early induction of genes involved in lipid metabolism, which fits with the crucial role of ER in the prevention of liver steatosis. Characterization of the chromatin state of ER binding sites (BSs) in mice expressing or not ER demonstrated that ER is not required per se for the establishment and/or maintenance of chromatin modifications at the majority of its BSs. This is presumably a consequence of a strong overlap between ER and hepatocyte nuclear factor 4 alpha BSs. In contrast, 40% of the BSs of the pioneer factor forkhead box protein a (Foxa2) were dependent upon ER expression, and ER expression also affected the distribution of nucleosomes harboring dimethylated lysine 4 of Histone H3 around Foxa2 BSs. We finally show that, in addition to a network of liver-specific transcription factors including CCAAT/enhancer-binding protein and hepatocyte nuclear factor 4 alpha, ER might be required for proper Foxa2 function in this tissue.
ISSN: 0888-8809

hal-01357623
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01357623
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01357623/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01357623/file/Changes%20in%20gene%20expression%201%20and%20Estrogen%20Receptor_accepted.pdf
DOI : 10.1210/me.2015-1311

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: HCV treatment uptake has drastically increased in HIV-HCV coinfected patients in France since direct-acting antiviral (DAA) treatment approval, resulting in HCV cure in 63% of all HIV-HCV patients by the end of 2015. We investigated the impact of scaling-up DAA on HCV prevalence in the whole HIV population and in various risk groups over the next 10 years in France using a transmission dynamic compartmental model.Methods: The model was based on epidemiological data from the French Dat’AIDS cohort. Eight risk groups wereconsidered, including high-risk (HR) and low-risk (LR) men who have sex with men (MSM) and male/female heterosexuals,intra-venous drug users, or patients from other risk groups. The model was calibrated on prevalence and incidence dataobserved in the cohort between 2012 and 2015.Results: On January 1, 2016, 156,811 patients were registered as infected with HIV in France (24,900 undiagnosedpatients) of whom 7938 (5.1%) had detectable HCV-RNA (722 undiagnosed patients). Assuming a treatmentcoverage (TC) rate of 30%/year (i.e., the observed rate in 2015), model projections showed that HCV prevalenceamong HIV patients is expected to drop to 0.81% in 2026. Sub-analyses showed a similar decrease of HIV-HCVprevalence in most risk groups, including LR MSM. Due to higher infection and reinfection rates, predicted prevalencein HR MSM remained stable from 6.96% in 2016 to 6.34% in 2026. Increasing annual TC rate in HR MSM to 50/70%would decrease HCV prevalence in this group to 2.35/1.25% in 2026. With a 30% TC rate, undiagnosed patients wouldaccount for 34% of HCV infections in 2026.Conclusions: Our model suggests that DAA could nearly eliminate coinfection in France within 10 years for most riskgroups, including LR MSM. Elimination in HR MSM will require increased TC.
ISSN: 1741-7015

Droits : info:eu-repo/semantics/OpenAccess
inserm-01685739
http://www.hal.inserm.fr/inserm-01685739
http://www.hal.inserm.fr/inserm-01685739/document
http://www.hal.inserm.fr/inserm-01685739/file/2017%2C%20Virlogeux%20-%20Modeling%20HIV-HCV%20coinfection.pdf
DOI : 10.1186/s12916-017-0979-1

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
BACKGROUND: The use of pesticides and the related environmental contaminations can lead to human exposure to various molecules. In early-life, such exposures could be responsible for adverse developmental effects. However, human health risks associated with exposure to complex mixtures are currently under-explored. OBJECTIVE: THIS PROJECT AIMS AT ANSWERING THE FOLLOWING QUESTIONS: What is the influence of exposures to multiple pesticides on the metabolome? What mechanistic pathways could be involved in the metabolic changes observed? METHODS: Based on the PELAGIE cohort (Brittany, France), 83 pregnant women who provided a urine sample in early pregnancy, were classified in 3 groups according to the surface of land dedicated to agricultural cereal activities in their town of residence. Nuclear magnetic resonance-based metabolomics analyses were performed on urine samples. Partial Least Squares Regression-Discriminant Analysis (PLS-DA) and polytomous regressions were used to separate the urinary metabolic profiles from the 3 exposure groups after adjusting for potential confounders. RESULTS: The 3 groups of exposure were correctly separated with a PLS-DA model after implementing an orthogonal signal correction with pareto standardizations (R2 = 90.7% and Q2 = 0.53). After adjusting for maternal age, parity, body mass index and smoking habits, the most statistically significant changes were observed for glycine, threonine, lactate and glycerophosphocholine (upward trend), and for citrate (downward trend). CONCLUSION: This work suggests that an exposure to complex pesticide mixtures induces modifications of metabolic fingerprints. It can be hypothesized from identified discriminating metabolites that the pesticide mixtures could increase oxidative stress and disturb energy metabolism.
ISSN: 1932-6203

inserm-00863407
http://www.hal.inserm.fr/inserm-00863407
http://www.hal.inserm.fr/inserm-00863407/document
http://www.hal.inserm.fr/inserm-00863407/file/journal.pone.0064433.pdf
PUBMED : 23704985

Éditeur(s) : HAL CCSD
Résumé : A database providing information on mosquito specimens (Arthropoda: Diptera: Culicidae) collected in French Guiana is presented. Field collections were initiated in 2013 under the auspices of the CEnter for the study of Biodiversity in Amazonia (CEBA: http://www.labexceba.fr/en/). This study is part of an ongoing process aiming to understand the distribution of mosquitoes, including vector species, across French Guiana. Occurrences are recorded after each collecting trip in a database managed by the laboratory Evolution et Diversité Biologique (EDB), Toulouse, France. The dataset is updated monthly and is available online. Voucher specimens and their associated DNA are stored at the laboratory Ecologie des Forêts de Guyane (Ecofog), Kourou, French Guiana. The latest version of the dataset is accessible through EDB’s Integrated Publication Toolkit at http://130.120.204.55:8080/ipt/resource.do?r=mosquitoessur french_guiana or through the Global Biodiversity Information Facility data portal at http://www.gbif.org/dataset/5a8aa2ad-261c-4f61-a98e-26dd752fe1c5 It can also be viewed through the Guyanensis platform at http://guyanensis.ups-tlse.fr
ISSN: 1313-2989

hal-01601967
https://hal.archives-ouvertes.fr/hal-01601967
DOI : 10.3897/zookeys.532.6176
PRODINRA : 397188
PUBMED : 26692809