Two-cross-polarized-frequency VECSEL at 852nm for CPT-based Cs clocks (poster)

International audienceWe demonstrate a tunable high-purity microwave signal generation from a cross- polarized dual-frequency diode-pumped vertical external-cavity semiconductor laser operating at 852 nm for the coherent population trapping of cesium atoms in compact atomic frequency references

Opposite role of Bax and BCL-2 in the anti-tumoral responses of the immune system

BACKGROUND: The relative role of anti apoptotic (i.e. Bcl-2) or pro-apoptotic (e.g. Bax) proteins in tumor progression is still not completely understood. METHODS: The rat glioma cell line A15A5 was stably transfected with human Bcl-2 and Bax transgenes and the viability of theses cell lines was analyzed in vitro and in vivo. RESULTS: In vitro, the transfected cell lines (huBax A15A5 and huBcl-2 A15A5) exhibited different sensitivities toward apoptotic stimuli. huBax A15A5 cells were more sensitive and huBcl-2 A15A5 cells more resistant to apoptosis than mock-transfected A15A5 cells (pCMV A15A5). However, in vivo, in syngenic rat BDIX, these cell lines behaved differently, as no tumor growth was observed with huBax A15A5 cells while huBcl-2 A15A5 cells formed large tumors. The immune system appeared to be involved in the rejection of huBax A15A5 cells since i) huBax A15A5 cells were tumorogenic in nude mice, ii) an accumulation of CD8+ T-lymphocytes was observed at the site of injection of huBax A15A5 cells and iii) BDIX rats, which had received huBax A15A5 cells developed an immune protection against pCMV A15A5 and huBcl-2 A15A5 cells. CONCLUSIONS: We show that the expression of Bax and Bcl-2 controls the sensitivity of the cancer cells toward the immune system. This sensitization is most likely to be due to an increase in immune induced cell death and/or the amplification of an anti tumour immune respons

Deciphering the Structure, Growth and Assembly of Amyloid-Like Fibrils Using High-Speed Atomic Force Microscopy

Formation of fibrillar structures of proteins that deposit into aggregates has been suggested to play a key role in various neurodegenerative diseases. However mechanisms and dynamics of fibrillization remains to be elucidated. We have previously established that lithostathine, a protein overexpressed in the pre-clinical stages of Alzheimer's disease and present in the pathognomonic lesions associated with this disease, form fibrillar aggregates after its N-terminal truncation. In this paper we visualized, using high-speed atomic force microscopy (HS-AFM), growth and assembly of lithostathine protofibrils under physiological conditions with a time resolution of one image/s. Real-time imaging highlighted a very high velocity of elongation. Formation of fibrils via protofibril lateral association and stacking was also monitored revealing a zipper-like mechanism of association. We also demonstrate that, like other amyloid ß peptides, two lithostathine protofibrils can associate to form helical fibrils. Another striking finding is the propensity of the end of a growing protofibril or fibril to associate with the edge of a second fibril, forming false branching point. Taken together this study provides new clues about fibrillization mechanism of amyloid proteins

Assessing walking posture with geometric morphometrics: Effects of rearing environment in pigs

International audienceRearing social animals like pigs in isolation from conspecifics can have consequences on behaviour and physiology. The aim of this experiment was to determine whether rearing conditions affect body postures. We adapted a method for quantitative evaluation of postures based on geometric morphometrics, developed in horses, for pigs and applied it in different conditions. Forty eight 75-day old females were reared either alone in 2.25 m2 pens (IH, N = 24 animals and 4 groups) or in groups of four in 4.64 m2 pens (GH, N = 24) for two weeks. They were habituated to human handling (stroking, speaking) and marking on their backs every day, and tested individually once a day for 10 min in a corridor outside the home pen during the two subsequent weeks. We observed their behaviour and posture during the first exposure to the test (novelty), and the fourth and fifth (after habituation). On the sixth and seventh tests, a familiar stockperson was present in the corridor (human presence). Before each test, the animals were marked with seven landmarks along their length, corresponding to anatomical points and easily located. An experimenter took pictures of the animals walking along the corridor, and these pictures were transferred to tps software for analysis. GH animals were more often active in the rearing pen than IH (median (IQ) 15% of observations [12-20%] versus 2% [0-13%]; P < 0.05). All animals except one IH initiated contact with the handler during the last sessions of handling (Fisher's exact test, ns). Principal Component Analyses revealed significant effects of rearing and testing conditions on pigs’ behaviour and posture. Novelty led to fewer vocalisations and more exploration for IH than GH animals (P < 0.05), but there were no differences between treatments after habituation to the testing situation. The backs of IH animals were more rounded than those of GH (P < 0.05; dimension 1 of PCA), independently of the test condition. Human presence had no effect on posture. In conclusion, the method based on geometric morphometrics that we developed to study pig posture detected variations in walking posture in pigs associated with rearing conditions. Postures might reflect affective states in pigs, as shown in other species, but further studies are needed to verify thi

Résolution de procesus décisionnels de Markov totalement observables de grandes tailles

La planification sous incertitude, fortement étudiée ces dernières années en Intelligence Artificielle, utilise souvent les Processus Décisionnels de Markov. Nous nous sommes donc focalisés, dans cette thèse, sur cette technique. Afin de cerner au mieux cette méthode issue de la Recherche Opérationnelle, nous nous sommes concentrés sur sa description formelle et ses techniques de résolution illustrées par l'exemple d'une station météo mobile qui se veut autonome et capable de prendre diverses mesures météorologiques sur plusieurs sites géographiques. Notre première contribution montrera, par l'exemple, l'applicabilité de cette technique à l'exemple du rover de la NASA et mettra en avant une amélioration d'un des algorithmes de résolution. Néanmoins, cette contribution mettra en avant une des limites des Processus Décisionnels de Markov : la taille des instances considérées. Notre deuxième contribution se focalise sur les techniques de décomposition qui est une solution de type "diviser pour régner" au problème de résolution de Processus Décisionnels de Markov de grandes tailles. En effet, nous présentons un algorithme "efficace" de résolution de Processus Décisionnels de Markov décomposés.There has been much research about planning under uncertainty in Artificial Intelligence these last years. Such a form of planning often uses Markov Decision Processes (MDPs). In this thesis, the focus is on both the formalization of MDPs and their resolution techniques. Our contribution is illustrated by means of the example of the NASA rover, which is a mobile meteorological station that must autonomous and capable of taking different meteorological measures on several geographic sites. The first contribution of the thesis concerns the applicability of MDPs to the rover and an improvement of one of the resolution algorithms. It also illustrates the tractability limits of such approaches for tractable instances. In the spirit, a second contribution of the thesis concerns decomposition techniques for large MDPs in order to boost their resolution.LENS-BU Sciences (624982102) / SudocSudocFranceF

Le collage amélaire en orthodontie peut-il induire une altération du substrat ?

Le collage d'attaches orthodontiques est une étape indispensable pour la majorité des thérapeutiques d'orthopédie dento-faciale. Il s agit d'un collage transitoire dont l'objectif est à la fois de résister aux forces appliquées sur l interface par l environnement oral et les forces orthodontiques contenues dans les arcs, et de permettre de restituer un substrat amélaire comparable après traitement à son état initial. Les modifications de l'émail peuvent se produire lors des différentes étapes du traitement orthodontique : nettoyage et traitement de surface des dents avant collage, rétention de plaque et décollements accidentels lors du port du dispositif orthodontique, décollement intentionnel des attaches, finitions et polissage. Une étude in vitro permet de comparer l'état de surface amélaire de 15 échantillons avant et après collage orthodontique, principalement par mesure de l angle de contact entre une goutte d eau et l'émail et par spectrométrie infrarouge à transformée de Fourier.NANTES-BU Médecine pharmacie (441092101) / SudocNANTES-Bib.Odontologie (441092219) / SudocSudocFranceF

Conjugated linoleic acid (CLA) isomers in heat-treated vegetable oils

The aim of this study was to quantify the conjugated linoleic acids (CLA) isomers present in frying oils and to elucidate their structures. For this purpose, used frying oils were collected in restaurants by the Laboratoire Interrégional de la Répression des Fraudes. Three samples of sunflower oils, one of peanut oil and one of rapeseed oil containing different levels of total polar compounds were analys-ed. The samples were converted to methyl esters using sodium methoxide and the CLA content was determinated by a combination of gas chromatography analysis on a 100m CP Sil88 column and of silver-ion-high pressure liquid chromatography. The identification of the CLA isomers was carried out by gas chromatography coupled with mass spectrometry of the 4-methyl-1,2,4-triazoline-3,5-dione adducts. The amount of polar compounds in the frying oils ranged from 30 to 53%. The quantities of CLA from 0.4 to 0.5%. The 9,11 and 10,12-18:2 were the major CLA isomers. Among them, the di-trans isomers represent about 50% of the total CLA

Conjugated linoleic acid (CLA) isomers in heat-treated vegetable oils

The aim of this study was to quantify the conjugated linoleic acids (CLA) isomers present in frying oils and to elucidate their structures. For this purpose, used frying oils were collected in restaurants by the Laboratoire Interrégional de la Répression des Fraudes. Three samples of sunflower oils, one of peanut oil and one of rapeseed oil containing different levels of total polar compounds were analys-ed. The samples were converted to methyl esters using sodium methoxide and the CLA content was determinated by a combination of gas chromatography analysis on a 100m CP Sil88 column and of silver-ion-high pressure liquid chromatography. The identification of the CLA isomers was carried out by gas chromatography coupled with mass spectrometry of the 4-methyl-1,2,4-triazoline-3,5-dione adducts. The amount of polar compounds in the frying oils ranged from 30 to 53%. The quantities of CLA from 0.4 to 0.5%. The 9,11 and 10,12-18:2 were the major CLA isomers. Among them, the di-trans isomers represent about 50% of the total CLA

The intertidal sanding up of the Seine-Maritime coast (Normandy, France): Sedimentological and geochemical approaches

International audienceThe Seine-Maritime coastline (France) is a macro-tidal environment (8 m tidal range), developingalong an epicontinental sea, the English Channel. The SW-NE coast is opened to westerlyatmospheric flows, generating occasionally wind sea with energetic waves (Hs: 4.65 m decennialreturn). High chalk cliffs and a wide marine erosion platform partially hidden on its upper part by aflint pebble beach, characterise this 130 km long coast.Observations since the end of the 1990’s show a recent and massive sanding up of the marineerosion platform. This raises the question of the origin of the sandy fraction and the sedimentarydynamics on the intertidal area.We present herein an innovative method that combine grain-size and geochemical analysis inorder to highlight sand sources and transport direction along these rocky coast.Sixteen beaches were sampled during low tide and fair-weather conditions. At each site, 3 sampleswere collected along the cross-shore beach profile (from the pebbly upper beach to the low tidelimit).Grain-size results show that for all sites, medium to coarse-grained sands dominate in the upperbeach (mode 315-400μm) while fine sands dominate in the middle and low foreshore (mode160-250μm). A decrease in grain-size is thus evidenced from the upper beach to the low foreshore.The geographical variability of the sand composition and consequently sources was determinedon the basis of geochemical data. In order to avoid the granulometric effect on the data, X-Rayfluorescence analysis (xSORT, SPECTRO AMETEK) were performed on the two major grain-sizemodes of each sample. Eighteen calibrated chemical elements (Si, S, K, Ca, Ti, V, Mn, Fe, Ni, Ga, As,Br, Rb, Sr, Y, Pb, Th and U) were measured at each station. Statistical processing performed step bystep on the data allows to gradually reduce the number of significant geochemical parameters.Finally, 4 major elements (Si, Ca, Sr, K) as well as the ratio Sr/Ca have been considered as the bestproxies of sample discrimination and potential source.The first results indicate a longshore gradient of Si and Ca, especially for the finest sands 60-200μm). From SW to NE, i.e. in the direction of the littoral drift, and whatever the positionacross the beach profile, there are an enrichment in Si (sands are more siliciclastic) and animpoverishment in Ca.This gradient highlights differentiated longshore sediment transport and sorting, in relationprobably with sediment sources (siliclastic sands vs bioclastics sands)

The intertidal sanding up of the Seine-Maritime coast (Normandy, France): Sedimentological and geochemical approaches

International audienceThe Seine-Maritime coastline (France) is a macro-tidal environment (8 m tidal range), developingalong an epicontinental sea, the English Channel. The SW-NE coast is opened to westerlyatmospheric flows, generating occasionally wind sea with energetic waves (Hs: 4.65 m decennialreturn). High chalk cliffs and a wide marine erosion platform partially hidden on its upper part by aflint pebble beach, characterise this 130 km long coast.Observations since the end of the 1990’s show a recent and massive sanding up of the marineerosion platform. This raises the question of the origin of the sandy fraction and the sedimentarydynamics on the intertidal area.We present herein an innovative method that combine grain-size and geochemical analysis inorder to highlight sand sources and transport direction along these rocky coast.Sixteen beaches were sampled during low tide and fair-weather conditions. At each site, 3 sampleswere collected along the cross-shore beach profile (from the pebbly upper beach to the low tidelimit).Grain-size results show that for all sites, medium to coarse-grained sands dominate in the upperbeach (mode 315-400μm) while fine sands dominate in the middle and low foreshore (mode160-250μm). A decrease in grain-size is thus evidenced from the upper beach to the low foreshore.The geographical variability of the sand composition and consequently sources was determinedon the basis of geochemical data. In order to avoid the granulometric effect on the data, X-Rayfluorescence analysis (xSORT, SPECTRO AMETEK) were performed on the two major grain-sizemodes of each sample. Eighteen calibrated chemical elements (Si, S, K, Ca, Ti, V, Mn, Fe, Ni, Ga, As,Br, Rb, Sr, Y, Pb, Th and U) were measured at each station. Statistical processing performed step bystep on the data allows to gradually reduce the number of significant geochemical parameters.Finally, 4 major elements (Si, Ca, Sr, K) as well as the ratio Sr/Ca have been considered as the bestproxies of sample discrimination and potential source.The first results indicate a longshore gradient of Si and Ca, especially for the finest sands 60-200μm). From SW to NE, i.e. in the direction of the littoral drift, and whatever the positionacross the beach profile, there are an enrichment in Si (sands are more siliciclastic) and animpoverishment in Ca.This gradient highlights differentiated longshore sediment transport and sorting, in relationprobably with sediment sources (siliclastic sands vs bioclastics sands)