Morphologie, morphométrie et systématique des coraux plocoïdes jurassiques (sous-ordre Stylinina)

Une nécessaire révision des coraux plocoïdes jurassiques en morphologie, morphométrie, systématique et en nomenclature a été réalisée grâce à des spécimens-types, du matériel de collection, ou issu de la littérature. Des structures dont une nouvelle muraille, l'étallonothèque et des types d'auricules ont été identifiés. Un stade initial ontogénique tétraméral a été observé pour la première fois chez Heliocoenia et Pseudocoenia. Ceci est en désaccord avec la définition traditionnelle sur le développement fondamentalement hexaméral chez les Scleractinia. L'étude systématique aboutit à une réorganisation des familles, des genres et de leurs synonymies. Des espèces sont décrites avec des limites encore parfois ambigües nécessitant une approche morphométrique plus approfondie pour être reproductible. Les positions systématiques prises sont traduites dans le sens de la préservation de la stabilité de l'usage des noms, des actes nomenclaturaux sont proposés dans ce sens. Deux méthodes morphométriques ont été appliquées aux contours 2D des sections de polypiérites. L'analyse de Fourrier Elliptique a été utilisée sur des coupes transversales théoriques et réelles. Les résultats montrent les différentes symétries et certains genres distingués par cette méthode. L'analyse des dimensions fractales de modèles théoriques, des coupes étudiées, ou issues de la littérature ont été analysées. Les formes étudiées se placent selon un gradient de complexité croissante du contour correspondant à la maximisation de l'interface squelette-porosité. Le long de ce gradient, les différents taxons se répartissent, leur distinction restant souvent délicate par suite d'un léger recouvrementA review of Jurassic plocoid corals in morphology, morphometry, systematics and in nomenclature was necessary. This study was realized with collection materials, type specimens and material from the literature. The morphological study enables identifying structures such as a new type of wall, the etallonotheca and some new types of auricles. A tetrameral initial ontogenetic stage was observed for the first time in Heliocoenia and Pseudocoenia. This is in disagreement with the traditional definition of the septal development supposed to be fundamentally hexameral in Scleractinia. The systematic study led to a significant reorganization of families, genera and their synonyms. Species are described but their limits are still ambiguous and so still require more detailed morphometric approaches to be reproducible. The systematic positions chosen here are translated in terms of nomenclature in order to preserve the stability of names. This requires in various cases nomenclatural acts. Two morphometric methods were applied on 2D contours of calices sections. Elliptical Fourier analysis was used on theoretical and real transversal sections. The results show that the different symmetries and some genera can be distinguished by this method. Analysis of fractal dimensions has also been applied. Theoretical models and the sections studied in this work or issued from the literature were analyzed. The studied forms are placed according to an increasing complexity gradient of the contour corresponding to the maximization of the interface skeleton-porosity. The different taxa are distributed along this gradient, due to their small overlaps; their true distinction often remains difficultMETZ-SCD (574632105) / SudocNANCY1-Bib. numérique (543959902) / SudocNANCY2-Bibliotheque electronique (543959901) / SudocNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

La limite oxfordien-Kimméridgien (jurassique supérieur) (stratigraphie et paléoenvironnements dans les royaumes téthysien (Est et Sud du Bassin de Paris, France) et boréal (ile de Skye, Ecosse))

L'intervalle Oxfordien supérieur/Kimméridgien inférieur (Jurassique supérieur, ~156 Ma) de la région de Lorraine/Champagne a fait l'objet d'une étude pluridisciplinaire en vue d'améliorer les corrélations entre les provinces boréales et téthysiennes. Les associations de fossiles (foraminifères, algues, brachiopodes, phytoclastes etc.) ainsi que les données géochimiques de l'Est du Bassin parisien révèlent un changement des conditions physico-chimiques de l'eau de la plate-forme lagonaire tropicale (dysoxie, diminution de température). Ces changements vont entraîner la quasi-disparition des organismes et empêcher la production de carbonates. Le refroidissement s'explique localement par le renforcement de courants apportant des eaux boréales fraîches envahissant la plate-forme. Des corrélations entre les dépôts de l'Est et ceux du Sud du Bassin parisien (Berry) ont permis d'améliorer le cadre chronologique de l'Est du Bassin parisien très pauvre en ammonites. La comparaison des cadres séquentiels permet de placer le maximum de régression d'un cycle eustatique de 3ème ordre reconnu et caractérisé par ailleurs (limite des zones à Planula et Platynota).Une succession située sur l'Ile de Skye a été proposée en tant que potentiel stratotype pour la limite Oxfordien/Kimméridgien. L'étude de la coupe de Flodigarry avait pour objectif de tenter de comparer cette succession subboréale à des dépôts subméditerranéens à travers différents marqueurs. L'analyse de la matière organique soluble a révélé des biomolécules très bien préservées, parmi les plus vieilles identifiées au mondeIsotopic ([delta]18O and [delta]13C) and elementary geochemical data as well as macro and microfossil associations, show a chemical change in the water of the lagoonal platform in the eastern Paris Basin, during the Late Oxfordian/Early Kimmeridgian interval (Upper Jurassic, ~156 Ma). Gradually, the shallow tropical environments dominated by biomineralization of carbonates became confined, dysoxic and colder. Correlations between depositional environments with similar facies in the Southern and in the Eastern Paris Basin helped to improve the biostratigraphic frameworks. Comparisons between the sequential frames deduced from the palaeoenvironmental evolution of Berry and Lorraine places the maximum regression of a 3rd order cycle at the Planula and Platynota ammonite zones boundary. Recently, the Flodigarry Shale Member, a shaly succession located on the Isle of Skye (Scotland), has been proposed as a possible GSSP (Global Stratotype Section and Point) to define the Oxfordian/Kimmeridgian boundary. The section was studied in order to compare this subboreal series to submediterranean deposits (Paris Basin) by means of other markers such as organic molecular contents. It revealed very well preserved biomolecules, among the oldest identified in the world. This thesis provides new palaeontological, geochemical and stratigraphic data in both Jurassic palaeobiogeographic realms. Well documented sections of the Eastern Paris Basin are now available for this interval. Such local observations, integrated in a multidisciplinary approach, should strengthen the correlations across these realms and precise the global components of the crisis of the carbonate production near the O/K boundaryNANCY1-Bib. numérique (543959902) / SudocSudocFranceF

Géométries et environnements de dépôt de l'Oxfordien de l'Est du Bassin de Paris

La variété des faciès et des environnements de dépôt de l'Oxfordien de Lorraine est à l'origine d'un nouveau découpage lithostratigraphique proposé dans ce mémoire. L'étude de l'Oxfordien de Lorraine à partir des données d'affleurement et des données de subsurface en termes de sédimentologie de faciès et de stratigraphie séquentielle a permis de décrire 13 cycles de dépôt transgressifs-régressifs. Les systèmes de dépôt ont évolué depuis une rampe argilo-carbonatée à vergence sud jusqu'à une rampe à argilo-carbonatée à vergence nord en passant par une plate-forme carbonatée récifale et/ou oolithique. Des amplifications des chutes du niveau marin relatif à haute fréquence s'observent en contexte transgressif et sont contemporaines de changements climatiques. Les 13 cycles de dépôt oxfordiens s'inscrivent dans 6 cycles transgressifs régressifs à moyenne fréquence pour lesquels les ennoyages sont contemporains d'évènements tectoniques dans 5 cas sur 6. Ces 6 derniers cycles s'inscrivent dans un cycle régressif-transgressif à basse fréquence dont le minimum d'accommodation se situe dans la partie supérieure de l'Oxfordien moyen.The diversity of facies and depositional environments of the Oxfordian of Lorraine allowed to propose a new lithostratigraphic framework. The survey of field and subsurface data using facies sedimentolgy and sequential stratigraphy allowed to describe 13 transgressive-regressive depositional cycles between the Mariae zone and the Planula zone. The depositional systems evolved from a marl-limestone ramp deepening southward, to a reefal and/or oolitic carbonate platform and finally to a marl-limestone ramp deepening northward. Amplifications of high frequency relative sea level falls appear in transgressive context and coïncide with climatic changes. Thirteen oxfordian depositional cycles are inserted in 6 medium frequency transgressive-regressive cycles and, in 5 cases, floodings are contemporaneous with tectonic events. Those 6 cycles are inserted in a low frequency regressive transgressive cycle and accommodation minimum appear in the upper part of the Middle Oxfordian.NANCY1-SCD Sciences & Techniques (545782101) / SudocSudocFranceF

Encapsulation device

Provided herein is a cell encapsulation device comprising an internal chamber suitable for holding biological agents, wherein the internal chamber is disposed between a first semipermeable layer and a second semi-permeable layer, and the first and second semi-permeable layers are mounted on a supporting frame surrounding a perimeter of the internal chamber; wherein the supporting frame comprises a first frame element and a second frame element, and the first and second frame elements co-operate to position the first and second semipermeable layers at a predetermined separation distance between the layers

The depth of pelagic deposits in the Tethyan Jurassic and the use of corals: an example from the Apennines

Assessing the palaeobathymery of pelagic deposits is rather speculative, as proof through lithology or fossils significant for depth estimates is sparse. This is unfortunate as the bathymetric history of pelagic successions allows to conceive the evolution of continental margins and oceanic basins. Discoveries in coral biology bring an unexpected impact on basin analysis. Evidence strongly suggests that pennular corals, fossil and modem, constitute a zooxanthellate group with an outstanding specialization in colonizing deeper parts of the marine photic zone. This adaptation includes light amplification by autofluorescent pigmented cells, and particular feeding, witnessed by peculiar gastric ducts and skeletal features. Such corals occur in the Umbria-Marche and Sabina Apennines on top of Late Jurassic submarine highs and at basin margins. Values of palaeodepth relative to pelagic deposits are provided by corals and other environmental data. Because depth reconstruction involves classical Tethyan facies, such as Ammonitico Rosso, Aptychus limestone and radiolarian cherts, we must note that these results do not meet with actualistic models relying on carbonate dissolution for estimating depth. Deposits viewed as bathyal to abyssal could also have accumulated within, or just below, the photic zone. Thus, a new insight opens on Mesozoic bathymetries, regarding vast areas (Middle East to Caribbean) and on subjects ranging from platform drowning to regional extension styles. (C) 2004 Elsevier B.V. All rights reserved

Oxygene Isotopes and climatic Control of Oxfordian Coral Reefs (Jurassic, Tethys)

International audienceStable isotope studies were carried out on shells of reef-dwelling brachiopods and oysters to evaluate the impact of climate changes on coral communities during the Oxfordian (Late Jurassic) in western Europe and northwestern Africa. Low to medium diversities observed in coral associations in the pioneering and terminal reef phases correlate well with average seawater paleotemperatures of <20.3 °C. The reef climax coincides with optimum environmental conditions, reflected by a high coral diversity and an average seawater temperature between 22 and 30 °C. The results of this study show that water temperatures set the physiological limits for the distribution of corals and coral reefs in Oxfordian time

Amyloid-beta plaque deposition measured using propagation-based X-ray phase contrast CT imaging

Amyloid beta accumulation into insoluble plaques (A beta p) is known to play a significant role in the pathological process in Alzheimer's disease (AD). The presence of A beta p is also one of the neuropathological hallmarks for the disease. AD final diagnosis is generally acknowledged after the evaluation of A beta p deposition in the brain. Insoluble A beta p accumulation may also concur to cause AD as postulated in the so-called amyloid hypothesis. Therefore, the visualization, evaluation and quantification of A beta p are nowadays the keys for a better understanding of the disease, which may point to a possible cure for AD in the near future. Synchrotron-based X-ray phase contrast (XPC) has been demonstrated as the only imaging method that can retrieve the A beta p signal with high spatial resolution (up to 10 mu m), high sensitivity and three-dimensional information at the same time. Although at the moment XPC is suitable for ex vivo samples only, it may develop into an alternative to positron emission tomography and magnetic resonance imaging in A beta p imaging. In this contribution the possibility of using synchrotron-based X-ray phase propagation computed tomography to visualize and measure A beta p on mouse brains is presented. A careful setup optimization for this application leads to a significant improvement of spatial resolution (similar to 1 mu m), data acquisition speed (five times faster), X-ray dose (five times lower) and setup complexity, without a substantial loss in sensitivity when compared with the classic implementation of grating-based X-ray interferometry

A high-capacity cell macroencapsulation system supporting the long-term survival of genetically engineered allogeneic cells

The rapid increase in the number of approved therapeutic proteins, including recombinant antibodies, for diseases necessitating chronic treatments raises the question of the overall costs imposed on healthcare systems. It is therefore important to investigate alternative methods for recombinant protein administration. The implantation of genetically engineered cells is an attractive strategy for the chronic long-term delivery of recombinant proteins. Here, we have developed a high-capacity cell encapsulation system for the implantation of allogeneic myoblasts, which survive at high density for at least one year. This flat sheet device is based on permeable polypropylene membranes sealed to a mechanically resistant frame which confine cells seeded in a tailored biomimetic poly(ethylene glycol) (PEG)-based hydrogel matrix. In order to quantitate the number of cells surviving in the device and optimize initial conditions leading to high-density survival, we implant devices containing C2C12 mouse myoblasts expressing a luciferase reporter in the mouse subcutaneous tissue. We show that initial cell load, hydrogel stiffness and permeable membrane porosity are critical parameters to achieve long-term implant survival and efficacy. Optimization of these parameters leads to the survival of encapsulated myogenic cells at high density for several months, with minimal inflammatory response and dense neovascularization in the adjacent host tissue. Therefore, this encapsulation system is an effective platform for the implantation of genetically engineered cells in allogeneic conditions, which could be adapted to the chronic administration of recombinant proteins. (C) 2013 Elsevier Ltd. All rights reserved