29 research outputs found
Développement des méthodes géophysiques électriques pour la caractérisation des sites et sols pollués aux hydrocarbures
Geophysics provides an overview of the basement in the form of maps and sections and gives valuable informations on the geology and the basement organization. Geoscope, partner of the project, is an engineering office specialized in soil diagnosis and buried objects searching and wants to develop environmental geophysics. The aim is to locate, limit and characterize hydrocarbon contaminated areas.The study focuses on the hydrocarbon contamination impact on the geoelectrical response, and more precisely on the spectral induced polarization response. Polarization mechanisms, which can be modified by hydrocarbons presence, occur on typical frequency ranges. Spectral induced polarization, which measures the response of a medium in the frequency domain, gives more precises informations than others methods which work in temporal domain.The effects of hydrocarbon presence are studied at different scales: (i) at the laboratory scale on synthetic media to understand response mechanisms (ii) across two contaminated sites to compare models developed in laboratory to real data, to evaluate the limits of the methods and to adapt protocols.La gĂ©ophysique procure une vision d'ensemble du sous-sol sous forme de cartes et de coupes et apporte des informations prĂ©cieuses sur la gĂ©ologie et l'organisation du sous-sol. Bureau d'Ă©tude spĂ©cialise dans les diagnostics de sols et la recherche d'objets enterrĂ©s, Geoscope, partenaire de la thĂšse CIFRE, dĂ©sire dĂ©velopper sa thĂ©matique gĂ©ophysique appliquĂ©e aux sites et sols polluĂ©s. L'objectif est de localiser, de limiter et caractĂ©riser les zones polluĂ©es aux hydrocarbures. LâĂ©tude porte sur lâimpact des pollutions hydrocarbonĂ©es sur la rĂ©ponse gĂ©oĂ©lectrique, et plus spĂ©cifiquement sur la rĂ©ponse en polarisation provoquĂ©e spectrale. Les mĂ©canismes de polarisation, qui peuvent ĂȘtre modifiĂ©s par la prĂ©sence dâhydrocarbures, interviennent sur des gammes de frĂ©quences caractĂ©ristiques. La polarisation provoquĂ©e spectrale, qui mesure la rĂ©ponse dâun milieu dans le domaine frĂ©quentiel, apporte des informations plus prĂ©cises que les autres mĂ©thodes gĂ©oĂ©lectriques qui fonctionnent dans le domaine temporel. Les effets de la prĂ©sence dâhydrocarbures sont Ă©tudiĂ©s Ă diffĂ©rentes Ă©chelles : (i) Ă lâĂ©chelle du laboratoire, sur des milieux synthĂ©tiques afin dâapprĂ©hender les mĂ©canismes de rĂ©ponse (ii) Ă lâĂ©chelle de deux sites polluĂ©s afin de confronter les modĂšles dĂ©veloppĂ©s en, laboratoire aux donnĂ©es rĂ©elles, dâapprĂ©cier les limites des mĂ©thodes et dâadapter les protocoles utilisĂ©s
Development of geophysical electrical methods for characterization of hydrocarbon contaminated sites and soils.
La gĂ©ophysique procure une vision d'ensemble du sous-sol sous forme de cartes et de coupes et apporte des informations prĂ©cieuses sur la gĂ©ologie et l'organisation du sous-sol. Bureau d'Ă©tude spĂ©cialise dans les diagnostics de sols et la recherche d'objets enterrĂ©s, Geoscope, partenaire de la thĂšse CIFRE, dĂ©sire dĂ©velopper sa thĂ©matique gĂ©ophysique appliquĂ©e aux sites et sols polluĂ©s. L'objectif est de localiser, de limiter et caractĂ©riser les zones polluĂ©es aux hydrocarbures. LâĂ©tude porte sur lâimpact des pollutions hydrocarbonĂ©es sur la rĂ©ponse gĂ©oĂ©lectrique, et plus spĂ©cifiquement sur la rĂ©ponse en polarisation provoquĂ©e spectrale. Les mĂ©canismes de polarisation, qui peuvent ĂȘtre modifiĂ©s par la prĂ©sence dâhydrocarbures, interviennent sur des gammes de frĂ©quences caractĂ©ristiques. La polarisation provoquĂ©e spectrale, qui mesure la rĂ©ponse dâun milieu dans le domaine frĂ©quentiel, apporte des informations plus prĂ©cises que les autres mĂ©thodes gĂ©oĂ©lectriques qui fonctionnent dans le domaine temporel. Les effets de la prĂ©sence dâhydrocarbures sont Ă©tudiĂ©s Ă diffĂ©rentes Ă©chelles : (i) Ă lâĂ©chelle du laboratoire, sur des milieux synthĂ©tiques afin dâapprĂ©hender les mĂ©canismes de rĂ©ponse (ii) Ă lâĂ©chelle de deux sites polluĂ©s afin de confronter les modĂšles dĂ©veloppĂ©s en, laboratoire aux donnĂ©es rĂ©elles, dâapprĂ©cier les limites des mĂ©thodes et dâadapter les protocoles utilisĂ©s.Geophysics provides an overview of the basement in the form of maps and sections and gives valuable informations on the geology and the basement organization. Geoscope, partner of the project, is an engineering office specialized in soil diagnosis and buried objects searching and wants to develop environmental geophysics. The aim is to locate, limit and characterize hydrocarbon contaminated areas.The study focuses on the hydrocarbon contamination impact on the geoelectrical response, and more precisely on the spectral induced polarization response. Polarization mechanisms, which can be modified by hydrocarbons presence, occur on typical frequency ranges. Spectral induced polarization, which measures the response of a medium in the frequency domain, gives more precises informations than others methods which work in temporal domain.The effects of hydrocarbon presence are studied at different scales: (i) at the laboratory scale on synthetic media to understand response mechanisms (ii) across two contaminated sites to compare models developed in laboratory to real data, to evaluate the limits of the methods and to adapt protocols
Spatially-Resolved Multiply-Excited Autofluorescence and Diffuse Reflectance Spectroscopy: SpectroLive Medical Device for Skin In Vivo Optical Biopsy
This contribution presents the development of an optical spectroscopy device, called SpectroLive, that allows spatially-resolved multiply-excited autofluorescence and diffuse reflectance measurements. Besides describing the device, this study aims at presenting the metrological and safety regulation validations performed towards its aimed application to skin carcinoma in vivo diagnosis. This device is made of six light sources and four spectrometers for detection of the back-scattered intensity spectra collected through an optical probe (made of several optical fibers) featuring four source-to-detector separations (from 400 to 1000 µm). In order to be allowed by the French authorities to be evaluated in clinics, the SpectroLive device was successfully checked for electromagnetic compatibility and electrical and photobiological safety. In order to process spectra, spectral correction and metrological calibration were implemented in the post-processing software. Finally, we characterized the device’s sensitivity to autofluorescence detection: excitation light irradiance at the optical probe tip in contact with skin surface ranges from 2 to 11 W/m², depending on the light source. Such irradiances combined to sensitive detectors allow the device to acquire a full spectroscopic sequence within 6 s which is a short enough duration to be compatible with optical-guided surgery. All these results about sensitivity and safety make the SpectroLive device mature enough to be evaluated through a clinical trial that aims at evaluating its diagnostic accuracy for skin carcinoma diagnosis
Inventaire et mesures du marquage spatial dans la grammaire des langues des signes
International audienc
Cholesterol accumulation induced by acetylated LDL exposure modifies the enzymatic activities of the TCA cycle without impairing the respiratory chain functionality in macrophages
International audienceThe unregulated uptake of modified low-density lipoproteins (LDL) by macrophages leads to foam cell formation, promoting atherosclerotic plaque progression. The cholesterol efflux capacity of macrophages by the ATP-Binding Cassette transporters depends on the ATP mitochondrial production. Therefore, the mitochondrial function maintenance is crucial in limiting foam cell formation. Thus, we aimed to investigate the mechanisms involved in the mitochondrial dysfunction that may occur in cholesterol-laden macrophages. We incubated THP-1 macrophages with acetylated LDL (acLDL) to obtain cholesterol-laden cells or with mildly oxidized LDL (oxLDL) to generate cholesterol- and oxidized lipids-laden cells. Cellular cholesterol content was measured in each condition. Mitochondrial function was evaluated by measurement of several markers of energetic metabolism, oxidative phosphorylation, oxidative stress, mitochondrial biogenesis and dynamics. OxLDL-exposed macrophages exhibited a significantly reduced mitochondrial respiration and complexes I and III activities, associated to an oxidative stress state and a reduced mitochondrial DNA copy number. Meanwhile, acLDL-exposed macrophages featured an efficient oxidative phosphorylation despite the decreased activities of aconitase, isocitrate dehydrogenase and α-ketoglutarate dehydrogenase. Our study revealed that mitochondrial function was differently impacted according to the nature of modified LDL. Exposure to cholesterol and oxidized lipids carried by oxLDL leads to a mitochondrial dysfunction in macrophages, affecting the mitochondrial respiratory chain functional capacity, whereas the cellular cholesterol enrichment induced by acLDL exposure results in a tricarboxylic acid cycle shunt while maintaining mitochondrial energetic production, reflecting a metabolic adaptation to cholesterol intake. These new mechanistic insights are of direct relevance to the understanding of the mitochondrial dysfunction in foam cells
Kaposiâs Sarcoma in Virally Suppressed People Living with HIV: An Emerging Condition
International audienceSince the advent of highly effective combined antiretroviral treatment (cART), and with the implementation of large HIV testing programs and universal access to cART, the burden of AIDS-related comorbidities has dramatically decreased over time. The incidence of Kaposiâs sarcoma (SK), strongly associated with HIV replication and CD4 immunosuppression, was greatly reduced. However, KS remains the most common cancer in patients living with HIV (PLHIV). HIV physicians are increasingly faced with KS in virally suppressed HIV-patients, as reflected by increasing description of case series. Though SK seem less aggressive than those in PLHIV with uncontrolled HIV-disease, some may require systemic chemotherapy. Persistent lack of specific anti-HHV-8 cellular immunity could be involved in the physiopathology of these KS. These clinical forms are a real therapeutic challenge without possible short-term improvement of anti-HHV-8 immunity, and no active replication of HIV to control. The cumulative toxicity of chemotherapies repeatedly leads to a therapeutic dead end. The introduction or maintenance of protease inhibitors in cART does not seem to have an impact on the evolution of these KS. Research programs in this emerging condition are important to consider new strategie