Search results for "Engineering sciences"
showing 10 items of 2347 documents
Toxicity of Branched-Chain Fatty Acids in Conjunctival Cell Line
2007
International audience; Purpose:: Tear film lipid composition is modified in patients suffering from chronic blepharitis. We previously found that branched chain fatty acids (BCFA) were significantly increased in tears of these patients, suggesting that BCFA may be involved in the disease. The toxicity of different BCFA as potent inducers of apoptosis has already been established in various cell lines but not in the conjunctiva. The aim of this work was to assess the toxic effects of BCFA in cultures of Chang conjunctival cells. Methods:: Chang’s human conjunctival cells were cultured during 4 or 24h with various concentrations of IsoC16 and IsoC20 as BCFA (from 50 to 200µM), by comparison …
Anti-inflammatory effects of GLA and EPA on a scopolamine-induced dry eye rat model
2007
International audience; Purpose:: The aim of this study was to evaluate the potential anti-inflammatory effects of dietary γ-linolenic acid (GLA) and eicosapentaenoic acid (EPA) in a scopolamine-induced dry eye rat model. Methods:: Female Lewis rats were fed with 5%-lipid diets containing 10% of either GLA or EPA. After two months of feeding, we induced dry eye syndrome using scopolamine continuously delivered via osmotic pumps for 2, 10 and 28 days. At the end of the treatment period, we performed fluorescein staining on the cornea. We sacrificed the animals and excised the ocular tissues and the exorbital lacrimal glands. We immunostained MHCII and mucin MUC5AC on ocular sphere cryosectio…
RPE/Choroid and Neuroretina Differences in Lipid Profile in Humans, and Possible Correlations to Dietary Lipid Intake
2008
International audience; Purpose: : To provide data on the differences in the lipid profile of the neural retina and RPE/choroid in healthy human eyes, and to establish plausible relationships with dietary fat intake, by comparing the lipid profile of the extra orbital fat. Methods: : Human eyes were collected from 28 human donors. The neural retina was dissected from the RPE/choroid. In 6 donors, the lacrimal gland and a piece of the extra orbital fat were collected. The lipid profile of the human samples was analyzed into classes. Phospholipids and cholesteryl esters were purified from RPE/choroid. The fatty acid composition of the retina, lipid fractions of RPE/choroid, and lacrimal gland…
The Exorbital Lacrimal Gland Is 100 Times More Susceptible Than the Retina to Dietary Supplies in Long Chain Omega-6 and Omega 3 Polyunsaturated Fatt…
2007
International audience; Purpose:: The purpose of this study was to compare the susceptibility of the retina and the exorbital lacrimal gland to dietary supplies in long chain omega-3 (ω3) and omega-6 (ω6) polyunsaturated fatty acids (LC-PUFAs). Methods:: Male Wistar rats were fed for 3 months with a 5% lipid-diet containing either: 1) 10% of EicosaPentaenoic Acid (EPA, ω3) and 7% of DocosaHexaenoic Acid (DHA, ω3), 2) 10% of γ-Linolenic Acid (GLA, ω6), 3) 10% of EPA, 7% of DHA and 10% of GLA or 4) a balanced diet deprived from EPA, DHA and GLA. After three months of feeding, lipids were extracted from the retina and the exorbital lacrimal gland and fatty acid composition was determined by ga…
Analyse morphologique de talwegs et comportement scalant : applications des dimensions non-entières à la géographie physique
1999
Morphological talweg analysis and scaling behaviour: applying non-integer dimension to physical geography. -- The organisation of the talweg network is fundamental to the erosion system on the silty loamy plateaux of north-western France. The morphology of the Pays de Caux is a good example of successive runoff concentration caused by the nesting of small dry valleys. These are inherited from a periglacial climate and their general direction is governed by tectonics. However the detailed pattern of these forms remains complex and without obvious explanation. Non-integer dimensions may offer a ceratin logic to this relatively chaotic pattern. This paper has therefore sought to demonstrate th…
Analytical and finite element analyses on reliability of carbon fibre reinforced plastics
2013
International audience
Statistique de l'efficacité de blindage de matériaux composites pour la 5G: méthodes avancées d'échantillonnage
2020
International audience; Cette proposition présente une méthodologie pour l'estimation statistique du niveau de protection offert par des matériaux composites constitués par des fibres de carbone sur une large gamme de fréquences contenant la bande 5G. La variabilité géométrique des nanostructures de carbone (essentiellement en termes de formes et de dimensions) impose, dans un premier temps, une caractérisation fréquentielle précise de la distribution statistique des propriétés diélectriques des matériaux. La propagation, dans un second temps, des incertitudes précédentes au niveau de l'efficacité de blindage des matériaux apporte des contraintes particulières quand aux méthodes statistique…
The perception of odor objects in everyday life: a review on the processing of odor mixtures
2014
International audience; Smelling monomolecular odors hardly ever occurs in everyday life, and the daily functioning of the sense of smell relies primarily on the processing of complex mixtures of volatiles that are present in the environment (e.g., emanating from food or conspecifics). Such processing allows for the instantaneous recognition and categorization of smells and also for the discrimination of odors among others to extract relevant information and to adapt efficiently in different contexts. The neurophysiological mechanisms underpinning this highly efficient analysis of complex mixtures of odorants is beginning to be unraveled and support the idea that olfaction, as vision and au…
Truncation effects on muscular fatigue indexes based on M waves analysis
2012
International audience; In this paper, we investigate muscular fatigue. We propose a new fatigue index based on the continuous wavelet transform (CWT) and compare it with the standard fatigue indexes from literature. Fatigue indexes are all based on the electrical activity of muscles (electromyogram) acquired during an electrically stimulated contraction (ES). The stimulator and electromyogram system, which were presented in a previous work, allows real-time analysis. The extracted fatigue parameters are compared between each other and their sensitivity to noise is studied. The effect of truncation of M waves is then investigated, enlightening the robustness of the index obtained using CWT.
Multi axis representation and Euclidean distance of muscle fatigue indexes during evoked contractions
2014
International audience; In this article, we proposed a new representation of muscular fatigue during evoked muscle contractions based on fatigue indexes such as peak to peak amplitude, RMS of the M wave, mean and median frequency and fatigue index calculated from continuous wavelet transform (I CWT). These new representations of muscle fatigue using multi axis represented and Euclidean distance give better insights on changes in physiological characteristics during muscle fatigue. This technique provides a fatigue index using several muscle characteristics. The use of other kinds of fatigue characteristics as force could also be possible.