Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Mechanical forces influence the growth and shape of virtually all tissues and organs. Recent studies show that increased cell contractibility, growth and differentiation might be normalized by modulating cell tensions. Particularly, the role of these tensions applied by the extracellular matrix during liver fibrosis could influence the hepatocarcinogenesis process. The objective of this study is to determine if 3D stiffness could influence growth and phenotype of normal and transformed hepatocytes and to integrate extracellular matrix (ECM) stiffness to tensional homeostasis. We have developed an appropriate 3D culture model: hepatic cells within three-dimensional collagen matrices with varying rigidity. Our results demonstrate that the rigidity influenced the cell phenotype and induced spheroid clusters development whereas in soft matrices, Huh7 transformed cells were less proliferative, well-spread and flattened. We confirmed that ERK1 played a predominant role over ERK2 in cisplatin-induced death, whereas ERK2 mainly controlled proliferation. As compared to 2D culture, 3D cultures are associated with epithelial markers expression. Interestingly, proliferation of normal hepatocytes was also induced in rigid gels. Furthermore, biotransformation activities are increased in 3D gels, where CYP1A2 enzyme can be highly induced/activated in primary culture of human hepatocytes embedded in the matrix. In conclusion, we demonstrated that increasing 3D rigidity could promote proliferation and spheroid developments of liver cells demonstrating that 3D collagen gels are an attractive tool for studying rigidity-dependent homeostasis of the liver cells embedded in the matrix and should be privileged for both chronic toxicological and pharmacological drug screening.
ISSN: 0730-2312

hal-01196600
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01196600
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01196600/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01196600/file/Increasing%203D%20Matrix%20Rigidity_accepted.pdf
DOI : 10.1002/jcb.25356

Éditeur(s) : HAL CCSD AGU and the Geochemical Society
Résumé : International audience
A NE-SW magnetotelluric 110 km-long profile including 18 sites was acquired across the western Rif Cordillera along the Eurasian-African plate boundary, allowing to constrain its poorly known deep structure. It extends from the Internal Zones, close to the Alboran coast, crossing the External Zones and up to the Gharb foreland basin. The periods recorded range from 0.001 s to 1000 s. The combination of magnetotelluric data with available geological data provides new insight regarding the relationship between deep and shallow crustal structures of the Rif Cordillera. Analyses of structural dimensionality suggest a preferential NW-SE direction, and a 2D joint inversion was performed. A 3D inversion extending the 2D model along the strike confirmed the reliability of this approach. The magnetotelluric model shows a heterogeneous upper crust in agreement with the geological structures observed at surface. The Internal Zones correspond to resistive (metamorphic rocks) and conductive (peridotites) bodies, while the External Zones and the foreland basin are characterized by large conductive bodies of variable thickness. A crustal detachment level separating shallow geological units from a probable variscan basement was inferred. At depth, the most relevant feature consists of large resistive bodies with a shallow irregular top, located below the frontal part of the Rif. The outcrops of exotic metapelitic, granitic and gneissic blocks in the frontal part of the Cordillera suggest that these large resistive bodies may correspond to a gneissic or granitic basement surrounded by metapelitic rocks. Late contractive thrust and diapiric processes were responsible for their uplift and shallow emplacement. The Rif constitutes an active southwestward vergent orogenic wedge, oblique to the present-day NW-SE convergent Eurasian-African plate boundary.
ISSN: 1525-2027

hal-00670999
https://hal.archives-ouvertes.fr/hal-00670999
DOI : 10.1029/2011GC003783

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : The Oman-Emirates is the largest and best-exposed ophiolite; consequently, it has attracted significant interest among scientists, together with serious conflicts. Most geologists regard this ophiolite as having formed in an intra-oceanic subduction zone before being accreted to the Arabian continent. Here, we propose an alternative scenario, supported by detailed field observations and integrated geophysics. The smaller Emirates part of the ophiolite was forced into a nearby continent, in the pre-collision stage of Tethyan closure. The contraction led to the exhumation of the mantle floor of segmented basins accreted in a rifted system similar to the present-day Gulf of California. The implied high temperature–high pressure metamorphism and the range of geochemical signatures were introduced during the process of rifting, whereas the larger Oman ophiolite was emplaced by obduction onto and along the subducting continental shore. This Ridge–Trench–Transform system might call for a new process to obduct over continents in particular Tethyan ophiolites.
ISSN: 0954-4879

hal-01526919
https://hal.archives-ouvertes.fr/hal-01526919
DOI : 10.1111/ter.12256

Éditeur(s) : HAL CCSD
Résumé : This study is designed to improve the understanding of structural, mechanical and petrophysical characteristics of deformation bands in porous sandstone such as their potential influence on fluid storage or migration in reservoir setting. Structural and petrophysical analysis of band networks from Provence show that permeability of band is mainly controlled by the degree of cataclasis and diagenetic processes at depth. Map-scale analysis of band networks underlines the major influence of tectonic regime on band distribution, organization and permeability. Band associated to normal-fault regime (cataclasis and low-permeability) are located around map-sclae-fault whereas band associated to thurst-fault regime (moderate cataclasis and permeability) are pervasively distributed in all the area. Reverse-sense band are cataclastic and low-permeabiilty around the Roquemaure thrust, which show the potential role of large-scale fault on structural and petrophysical characteristics of bands. This analysis also shows the influence of fault propagation on formation of low permeability catacastic bands. This analysis suggests also granulometry as factor controlling organization of band networks.A mechanical analysis of deformation bands is realized based on results from Provence. Yield envelopes of these materials are calculated from analytical solution. Triaxial tests done on sandstone (L'Etang quarry, Orange) confirm the shape of yield envelope theoretically calculated. Triaxial tests done on the poorly-lithified sands (Boncavaï quarry, Uchaux) show grain size, sorting and packing influencing yield envelope and cataclastic band localization at shallow burial depth. Stress paths are calculated for burial and tectonic event (extension and contraction) using the relationship between main stress and secondary stresses (K0) calibrated from well data. These different results are integrated into a model which allows to estimate type and structural characteristics of bands susceptible to form for a known geological setting.A structural, mechanical and petrophysical model is established form these results. This model is calibrated by permeability data from deformation bands of Provence and results from the mechanical model of strain localization. This model is also confronted to a synthesis of permeability data from literature, which confirms the influence of the different controlling parameters integrated to the model. This model is applied for two sites of uranium exploration/exploitation in porous sandstone reservoirs and validated by field observations.
Cette étude est destinée à améliorer la compréhension des caractéristiques structurales, pétrophysiques et mécaniques des bandes de déformation dans les grès poreux ainsi que de leur rôle potentiel sur la migration ou le piégeage des fluides en milieu réservoir. L'analyse structurale et pétrophysique des réseaux de bandes de Provence montre que leur perméabilité découle principalement de l'intensité de la cataclase dans leur microstructure et des processus diagénétiques qui peuvent s'y localiser avec la profondeur. L'analyse régionale de ces réseaux de bandes souligne l'influence majeure du régime tectonique sur leur distribution, leur organisation et leur perméabilité. Les bandes associées au régime normal (cataclactiques et peu perméables) sont localisées autour des failles cartographiques, tandis que les bandes associées au régime inverse (modérement cataclastiques et perméables) sont distribuées dans toute la région. Les bandes inverses sont fortement cataclastiques et imperméables uniquement autour du chevauchement de Roquemaure ce qui montre le rôle potentiel de la présence de grande faille sur les caractéristiques structurales et pétrophysiques de ces bandes. D'autre part, cette analyse suggère que la granulométrie de l'encaissant peut influencer l'initiation et l'organisation des réseaux. L'analyse mécanique des bandes de déformation a ensuite été réalisée à partir des résultats obtenus en Provence. L'enveloppe de plasticité de ces matériaux est calculée à l'aide d'une solution analytique. Les essais triaxiaux menés sur le grès de la carrière de l'Etang (orange) confirment la forme de ces enveloppes estimées théoriquement. Les essais réalisés sur les sables de Boncavaï (Uchaux) montrent que la taille des grains, le tri et de la compaction dans ces matériaux peu lithifiés influent sur leurs enveloppes de plasticité et la localisation des bandes cataclastiques à faibles profondeurs. Les trajets de contraintes sont estimés pour les phases d'enfouissement et de chargement tectonique (extension et compression) à partir de la relation entre contrainte principale et contraintes secondaires (K0), calibrée à partir de données de forage. Ces résultats sont intégrés à un modèle permettant d'estimer la nature et les caractéristiques structurales des bandes susceptibles de se former dans un contexte géologique donné. Un modèle structural, mécanique et pétrophysique a été établir à partir de ces différents résultats. Ce modèle est calibré à partir des données de perméabilité mesurées sur les bandes de Provence et des résultats du modèle mécanique de localisation cité précédemment. Ce modèle a ensuite été confronté à une synthèse des données de perméabilité disponibles dans la littérature et confirme l'influence des différents paramètres de contrôle pris en compte dans le modèle. Ce modèle a enfin pu être appliqué sur deux sites d'explorations/exploitations d'uranium en réservoir gréseux poreux et validé par les résultats obtenus, en concordance avec les observations de terrain.
https://tel.archives-ouvertes.fr/tel-01001389

NNT : 2013MON20067
tel-01001389
https://tel.archives-ouvertes.fr/tel-01001389
https://tel.archives-ouvertes.fr/tel-01001389/document
https://tel.archives-ouvertes.fr/tel-01001389/file/36072_BALLAS_2013_archivage-1_cor.pdf

Éditeur(s) : Caught in the "fishing net" of information 14th Biennal EURASLIC Meeting 17-20 May, 2011, Lyon, France
Résumé : In addition to its promotion and conservation objectives, Archimer, Ifremer’s institutional repository, offers a wide range of bibliometric tools described in this document. As early as the recording stage, numerous automatic operations homogenize the information (author’s name, research body, department…), thus proving the quality of the bibliometric analyses. Now, Archimer enables, among others, the automatic calculation of several indicators defined by Ifremer and the different ministries in charge in the framework of its four-year contract. It also offers various criteria aimed at analysing its document production (eg. distribution of the value of the journals’ impact factors, evolution of the number of quotations in other publications, presentation of international collaborations…). As a consequence, the centralisation of Ifremer’s document production in Archimer will replace a number of different systems currently used by its research units to carry out such tasks. This should therefore result in an increase in Ifremer’s productivity as well as in a greater reliability of the archived documents.
En complément de ses objectifs de diffusion et de conservation, Archimer, l’archive institutionnelle de l’Ifremer, offre un ensemble d’outils bibliométriques. Dès l'enregistrement, de nombreux automatismes homogénéisent les informations (noms d'auteurs, organismes, affiliation interne...), gage de qualité des analyses bibliométriques. Archimer permet le calcul automatique de plusieurs indicateurs définis entre l'Ifremer et ses Ministères de Tutelles dans le cadre de son contrat quadriennal. Il offre également des éléments d’analyses de sa production documentaire (ex : répartition de la valeur des facteurs d’impacts des revues, évolution du nombre de citations des publications, présentation des collaborations internationales…). La centralisation de cette production documentaire dans Archimer permettra ainsi l’abandon d’une multitude de systèmes actuellement utilisés par les différentes unités de recherche pour assurer ces fonctions. C’est donc un gain de productivité autant que de fiabilité qui est attendu.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00031/14253/11537.pdf
http://archimer.ifremer.fr/doc/00031/14253/11886.pdf
http://archimer.ifremer.fr/doc/00031/14253/

Éditeur(s) : HAL CCSD Geological Society of America
Résumé : International audience
Porous sandstones tend to deform by the formation of low-permeability deformation bands that influence fluid flow in reservoir settings. The bands may be distributed or localized into clusters, and limited recent data suggest that tectonic regime may exert control on their distribution and clustering. In order to explore this suggestion, we performed a synthetic analysis based of 73 sets of bands, including 22 new sets measured for a reverse Andersonian regime that fill the important gap in data for this context. We find a surprisingly strong correlation between clustering and tectonic regime, where bands clearly are more distributed in the reverse regime compared to the normal regime. Together with the observed band distributions, capillary pressure data show evidence that efficient membrane seals are expected for extension, whereas pervasive permeability anisotropy is expected for contraction. Such a basic new rule concerning tectonic regime is very useful for assessment of reservoir properties where deformation bands are common but below seismic resolution.
ISSN: 0091-7613

hal-01355925
https://hal.archives-ouvertes.fr/hal-01355925
DOI : 10.1130/G37585.1

Éditeur(s) : HAL CCSD
Résumé : International audience
The « METYSS » cruise was carried out in June 2009 onboard the R/V « Téthys II » along the eastern Sardinian and south-eastern Corsican margins, western Tyrrhenian Sea, in order to better constrain the potential links between deformation related to either crustal tectonics or salt tectonics and sediment accumulation, especially during the Messinian and Plio-Quaternary times. We acquired 15 high-resolution seismic reflection profiles (about 1200 km in cumulative length) along the south-eastern Corsican margin, immediately north of the Bonifacio Strait and along the upper and middle parts of the eastern Sardinian margin, from the continental slope to the Cornaglia Terrace. The Tyrrhenian Sea is considered as a Neogene back-arc basin that opened during continental rifting and oceanic spreading related to the eastward migration of the Apennine subduction system from Tortonian to Pliocene times (Jolivet et al., 2006). Rifting of the Tyrrhenian Sea started first along the Eastern Sardinian margin during the Tortonian-Messinian times and therefore the series of that age should be considered as syn-rift sediments (Sartori et al., 2004). The « METYSS » seismic profiles clearly illustrate that this part of the Tyrrhenian was highly segmented during the rifting stage by N-S trending normal faults delineating ridges (e.g., Baronie Ridge) and basins (e.g., Sardinian Basin and Cornaglia Terrace), as previously described for example by Thommeret (1999) and Sartori et al. (2004). The Messinian sedimentary units and especially the « Upper Unit » (UU, Lofi et al., this congress, corresponding to the « Upper Evaporites » in the previous literature) are, without any doubt, of syn-rift age, as they display a fan-shaped stratal geometry. The Mobile Unit (MU, Lofi et al., this congress), i.e. the Messinian halite, is clearly imaged in the study area and its spatial repartition can be outlined. The highly-variable thickness of the confined salt basins could be due to the initial basin geometry (i.e. before the Messinian salinity Crisis) or to the syn-rift character of the deposition. Southeastward of the study area, in the vicinity of the Cornaglia Seamount, salt tectonics appears surprisingly vigorous. More surprisingly, several normal faults seem to have remained active in recent times, if not even at present time. Fault slip has been recorded by bathymetric scarps and associated footwall debris flows interfingered within the Plio-Quaternary sequence, even though the eastern Sardinian margin is usually considered to be passive now. Moreover, some amount of tectonic inversion is visible on some normal faults that show contractional or transpressional components of late slip. In addition, this “post-rift” deformation can be illustrated within the Plio-Quaternary sequence by a regional unconformity. Consequently, numerous mass-transport deposits and channel-levees systems observed in the Plio-Quaternary cover could be partly controlled by tectonic activity. These very preliminary results require further investigations in order to better decipher the role of crustal tectonics and salt tectonics, salt-related structures being very efficient markers to discriminate between the respective contribution of gravity-driven, salt tectonics and deep-seated, crustal tectonics (Gaullier et al., 2010). Finally, we aim to precisely determine the relative vertical movements (tilting, subsidence, magmatism. . . ) and geodynamical history of the different segments of the area since 6 Ma.
Geophysical Research Abstracts
Vienne, Austria

hal-00537828
https://hal-brgm.archives-ouvertes.fr/hal-00537828
https://hal-brgm.archives-ouvertes.fr/hal-00537828/document
https://hal-brgm.archives-ouvertes.fr/hal-00537828/file/EGU2010-15469_ref6821.pdf

Résumé : Dans cette thèse nous présentons dans un premier temps une nouvelle notion de différentiabilité généralisée pour les applications multivoques, faisant intervenir des applications positivement homogènes: la H-différentiabilité. Nous étudions la stabilité de cette notion en utilisant la convergence de Fischer, d'abord dédiée aux ensembles mais que nous avons adaptée aux applications multivoques. Nous nous intéressons ensuite à l'étude de la dépendance continue des ensembles de points fixes d'une application multivoque contractante par rapport aux données. Finalement nous analysons la convergence d'une méthode d'approximations successives de type forward-backward splitting, des zéros de la somme de deux opérateurs multivoques non monotones, jouissants notamment de propriétés de pseudo H-différentiabilité
In this thesis we present at first a new concept of generalized differentiation for setvalued mappings, involving positively homogeneous applications: the H-differentiability. We study the stability of this notion by using Fischer convergence,firstly dedicated to sets but which we have adapted to set-valued mappings. We establish the continuous dependence of fixed points sets of set-valued contraction and finally we study the convergence of a forward-backward splitting method for approximating the zeros of the sum of two non-monotone set-valued mappings, notably using properties of pseudo H-differentiability.

http://www.theses.fr/2011AGUY0490/document