Etude et développement de caméras infrarouge multispectrales à acquisition simultanée pour la détection de gaz

The accidental emission of gas in an industrial platform or the use of chemical weapons can have dramatic consequences. Bertin Technology commercialize an infrared multispectral camera using an array of uncooled detectors and called Second Sight allowing the detection of numerous gas. However, the temporal acquisition of spectral images is a limitation for a use on mobile platforms (vehicles, drones...). Therefore, the purpose of my PhD was to study several concepts of snapshot multispectral cameras using a single array of uncooled detectors. I worked on two concepts of optical architectures: a kaleidoscope-based design and a multichannel design inspired by the TOMBO architecture. The kaleidoscope-based camera can use optimally the focal plane array while having an important aperture and a great range of Fields of View. However, it has an important footprint and the implementation of the multispectral function is not obvious. By comparing, the multichannel architecture can be very compact and easily adaptable for multispectral applications but a compromise between its aperture and its Field Of View is necessary. Following these studies, the TOMBO multichannel design was chosen as the successor of the Second Sight and I could make a first demonstrator. Finally, a radiometric model was developed to compare the different cameras and I showed that the TOMBO camera could have better performances than the Second Sight thanks to its snapshot feature.L’émission accidentelle de gaz sur des sites industriels ou l’utilisation d’armes chimiques peuvent avoir des conséquences dramatiques. Bertin Technologies commercialise une caméra multispectrale infrarouge utilisant un détecteur non-refroidi appelée Second Sight permettant de détecter de nombreux gaz. Cependant, l’acquisition temporelle des images spectrales est un frein pour une utilisation sur porteurs mobiles (véhicules, drones…). L’objet de la thèse a donc été d’étudier plusieurs concepts de caméras multispectrales à acquisition simultanée utilisant un seul détecteur non-refroidi. J’ai travaillé sur deux concepts d’architectures optiques : une architecture basée sur l’utilisation d’un kaléidoscope et une architecture multivoies inspiré de l’architecture TOMBO. L’architecture kaléidoscope a l’avantage d’utiliser de manière optimale le détecteur pour de fortes ouvertures et pour une grande variété de champs de vue. Elle est cependant encombrante et la fonction multispectrale reste délicate à intégrer. L’architecture multivoie, quant à elle, est très compacte et facilement adaptable à des applications multispectrales mais un compromis entre le champ de vue et l’ouverture doit être trouvé. Nous avons choisi cette architecture comme successeur de la Second Sight et j’ai pu réaliser un démonstrateur. Enfin, un modèle radiométrique a été développé pour comparer les différentes caméras et j’ai montré que la caméra TOMBO pouvait avoir de meilleures performances que la Second Sight grâce à l’acquisition simultanée des images multispectrales

Study and development of multispectral infrared snaphot cameras for gas detection

L’émission accidentelle de gaz sur des sites industriels ou l’utilisation d’armes chimiques peuvent avoir des conséquences dramatiques. Bertin Technologies commercialise une caméra multispectrale infrarouge utilisant un détecteur non-refroidi appelée Second Sight permettant de détecter de nombreux gaz. Cependant, l’acquisition temporelle des images spectrales est un frein pour une utilisation sur porteurs mobiles (véhicules, drones…). L’objet de la thèse a donc été d’étudier plusieurs concepts de caméras multispectrales à acquisition simultanée utilisant un seul détecteur non-refroidi. J’ai travaillé sur deux concepts d’architectures optiques : une architecture basée sur l’utilisation d’un kaléidoscope et une architecture multivoies inspiré de l’architecture TOMBO. L’architecture kaléidoscope a l’avantage d’utiliser de manière optimale le détecteur pour de fortes ouvertures et pour une grande variété de champs de vue. Elle est cependant encombrante et la fonction multispectrale reste délicate à intégrer. L’architecture multivoie, quant à elle, est très compacte et facilement adaptable à des applications multispectrales mais un compromis entre le champ de vue et l’ouverture doit être trouvé. Nous avons choisi cette architecture comme successeur de la Second Sight et j’ai pu réaliser un démonstrateur. Enfin, un modèle radiométrique a été développé pour comparer les différentes caméras et j’ai montré que la caméra TOMBO pouvait avoir de meilleures performances que la Second Sight grâce à l’acquisition simultanée des images multispectrales.The accidental emission of gas in an industrial platform or the use of chemical weapons can have dramatic consequences. Bertin Technology commercialize an infrared multispectral camera using an array of uncooled detectors and called Second Sight allowing the detection of numerous gas. However, the temporal acquisition of spectral images is a limitation for a use on mobile platforms (vehicles, drones...). Therefore, the purpose of my PhD was to study several concepts of snapshot multispectral cameras using a single array of uncooled detectors. I worked on two concepts of optical architectures: a kaleidoscope-based design and a multichannel design inspired by the TOMBO architecture. The kaleidoscope-based camera can use optimally the focal plane array while having an important aperture and a great range of Fields of View. However, it has an important footprint and the implementation of the multispectral function is not obvious. By comparing, the multichannel architecture can be very compact and easily adaptable for multispectral applications but a compromise between its aperture and its Field Of View is necessary. Following these studies, the TOMBO multichannel design was chosen as the successor of the Second Sight and I could make a first demonstrator. Finally, a radiometric model was developed to compare the different cameras and I showed that the TOMBO camera could have better performances than the Second Sight thanks to its snapshot feature

Preoperative hemoglobin level as a predictor of survival after coronary artery bypass grafting A comparison with the matched general population

Abstract Background—: The predictive value of the preoperative hemoglobin value after coronary artery bypass grafting (CABG) has not been well established. We studied how the preoperative hemoglobin level affects the survival of patients after CABG. Late mortality was compared with that of a general population. Methods and Results—: Early and late mortality of all consecutive patients undergoing isolated CABG between January 1998 and December 2007 were determined. Patients were classified into 4 groups stratified by preoperative hemoglobin level. The cutoff point for anemia was 13 g/dL for men and 12 g/dL for women. Expected survival of a matched general Dutch population cohort was obtained from the database of the Dutch Central Bureau for Statistics. After the exclusion of 122 patients who were lost to follow-up and 481 patients with missing preoperative hemoglobin levels, complete data were obtained in 10 025 patients. Multivariate logistic regression analyses revealed anemia to be an independent risk factor for higher early mortality. Cox regression analyses revealed low hemoglobin level, both as a continuous variable and as a dichotomous variable (anemia), to be a predictor of higher late mortality. Compared with expected survival, patients with the lowest preoperative hemoglobin levels had a worse outcome, whereas patients with the highest hemoglobin levels had a better outcome

Divalent cations influence the dimerization mode of murine S100A9 protein by modulating its disulfide bond pattern

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Kaleidoscope-based multi-view infrared system

International audienceMulti-view snapshot systems are used for a wide range of applications in all the spectral ranges. In this Letter, we present the study and the realization of an optical system using a kaleidoscope in the long wavelength infrared (LWIR), compatible with uncooled infrared detectors such as microbolometers. The optical system has a high numerical aperture and a wide field of view, and it uses a single focal plane array. Here, we establish the advantages of this technology on other design strategies and its design rules for every subset of the optical architecture, and we present the results of a first demonstrator.compatible with uncooled infrared detectors such as microbolometers. The optical system has a high optical aperture, a wide field of view and uses a single focal plane array. We establish here the advantages of this technology on other design strategies, its design rules for every subset of the optical architecture and present the results of a first demonstrator.Les systèmes multi-images snapshot sont utilisés pour un large éventail d'applications dans toutes les gammes spectrales.Nous soumettons ici l'étude et la réalisation d'un système optique utilisant un kaléidoscope dans l'infrarouge bande III (LWIR) et compatible avec les détecteurs infrarouges non refroidis tels que les microbololomètres. Le système optique présente une ouverture numérique élevée, un large champ de vision et utilise un détecteur unique. Nous établissons ici les avantages de cette technologie sur d’autres stratégies de conception, ses règles de conception pour chaque sous-ensemble de l’architecture optique et nous en présentons les résultats d'un premier démonstrateur

Comparison of a kaleidoscope-based multi-view infrared system with its TOMBO-based counterpart

International audienceMulti imaging snapshot systems are used for a wide range of applications in all the spectral ranges. We propose here a study and a realization of a multi-view snapshot system using a kaleidoscope in the Long-Wave Infrared (LWIR) and compatible with uncooled infrared detectors such as microbolometers. The optical system has a high numerical aperture, a wide range of fields of view and uses a single focal plane array. We will establish here the advantages of this technology on other design strategies and especially the kaleidoscope design will be compared with the TOMBO design. Then the optical conception rules for every subset of the kaleidoscope architecture will be described and the results of a first demonstrator will be presented. The features of this system will be compared with a TOMBO-based system with a front afocal.Les systèmes permettant l'acquisition de plusieurs images simultanément, dits "snapshot", sont utilisés pour une large gamme d'applications dans toutes les gammes de longueur d'onde. Nous proposons ici une étude et une réalisation d'un système snapshot multi-image utilisant un kaléidoscope dans l'infrarouge lointain (LWIR) et compatible avec des détecteurs infrarouges non refroidis tels que les microbolomètres. Le système optique dispose d'une grande ouverture numérique, d'une large plage de champs de vue accessibles et utilise un seul détecteur pour toutes les images. Nous établirons ici les avantages de cette technologie sur d'autres stratégies de conception et les performances de l'architecture kaléidoscope seront comparées à celles de l'architecture TOMBO. Ensuite, les règles de conception optique pour chaque sous-ensemble de l'architecture du kaléidoscope seront décrites et les résultats d'une première maquette seront présentés. Les caractéristiques de ce système seront comparées à celles d'un système type TOMBO couplé à un afocal

Effect of Body Mass Index on Early and Late Mortality After Coronary Artery Bypass Grafting

Abstract: Background. The effect of obesity on the long-term outcome after coronary artery bypass graft surgery (CABG) remains controversial. We analyzed data of patients undergoing CABG in a single center, to determine the predictive value of body mass index in combination with comorbidities on early and late mortality. Methods. Early and late mortality of consecutive patients undergoing isolated CABG from January 1998 until December 2007 were determined. Patients were classified into five groups according to preoperative body mass index: underweight, normal weight, overweight, obese, and morbidly obese. Results. After excluding 122 patients who were lost to follow-up and 236 patients with missing preoperative body mass index, 10,268 patients were studied. Multivariate logistic regression analyses showed that underweight was associated with higher early mortality (hazard ratio 2.63; 95% confidence interval: 1.13 to 6.11, p = 0.025). Multivariate Cox regression analyses did reveal morbid obesity as an independent predictor of late mortality (hazard ratio 1.67, 95% confidence interval: 1.15 to 2.43, p = 0.007). Conclusions. Among patients undergoing isolated CABG, underweight is an independent predictor for early mortality, and morbid obesity is an independent predictor for late mortality. (Ann Thorac Surg 2010; 89: 30-7) (C) 2010 by The Society of Thoracic Surgeon

Rock typing et hétérogénéité de la formation des grès de Roda (Eocène inférieur, Bassin sud pyrénéen) : un analogue de terrain aux réservoirs deltaïques

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Réalisation d'un modèle photogrammétrique d'affleurement des Grès de Roda (Eocène inférieur, Bassin sud-pyrénéen) pour l'étude des hétérogénéités réservoirs (projet UPGEO)

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Exploitation of the Leptosphaeria maculans late effector repertoire for diversification of resistances to blackleg in Brassica napus

International audienceLeptosphaeria maculans is a phytopathogenic fungus being responsible for a damaging disease of oilseed rape (Brassica napus): stem canker. The disease is mainly controlled by plant genetic resistance: single-gene specific resistance or quantitative, adult-stage resistance. During its particularly complex and long infectious cycle, L. maculans colonizes asymptomatically the stems of oilseed rape, producing late effectors specific to this colonization stage. In the context of a strong need to identify new sources of disease resistance, we exploited the repertoire of ‘late’ effectors to identify genes in the plant that could contribute to quantitative disease resistance. Our hypothesis was that quantitative resistance partly rely on gene-for-gene interactions, with fungal effectors produced during stem infection being recognized by resistance proteins. Using an innovative strategy of early expression of late effector genes, we validated that the interaction between the late effector LmSTEE98 and the resistance RlmSTEE98 obeys a typical gene-for-gene interaction, occurring during the colonization of oilseed rape stems by L. maculans, that contributes partly to quantitative resistance, in controlled conditions. We then used the same strategy to search for new sources of resistance after having established criteria to select the most relevant late effectors, and chosen ten of these for screening. Our screening approach of 130 diversified genotypes representative of the available diversity of B. napus, allowed us to identify new sources of resistance, displaying diversified interaction phenotypes. The next steps of this project now are further validation of the efficacy of the new sources of resistance in the field and of the validity of the quantitative resistance markers. However, as it stands, our results demonstrate the existence of unsuspected sources of resistance that are potentially more durable than the classic major genes expressed early after penetration in plant tissues