Cell migration within confined sandwich-like nanoenvironments

Aim: We introduced sandwich-like cultures to provide cell migration studies with 4 representative nano-bio-environments where both ventral and dorsal cell receptors are activated. Methods: We have investigated different nano-environmental conditions by changing the protein coating (fibronectin, vitronectin) and/or materials (using polymers that adsorb proteins in qualitatively different conformations) of this sandwich system to show their specific role in cell migration. Results: Here we show that cell migration within sandwich cultures greatly differs from 2D cultures and shares some similarities with migration within 3D environments. Beyond differences in cell morphology and migration, dorsal stimulation promotes cell remodeling of the ECM over simple ventral 12 receptor activation in traditional 2D cultures.</p

New Order, end of illusions and the activist matrix of the first National Front

Ordre nouveau was the most important French neo-fascist movement after 1945. It lasted only for four years (1969-1973) but it induced seve-ral changes shaking the radical right wing. As it was defined as a revolutionary party, ordre nouveau spread its identity onto activists on the one hand, while it also collaborated with state authorities fighting against leftists on the other hand. Following the successful italian model of the MSI, the movement oscillated between media coverage — which gave it an identity but also led to its dissolution in 1973 — and acceptance of the electoral game for which Front national had been founded. The disappearance of ordre nouveau meant the end of dreams of revolutionary right sustained by some active minorities using political violence, as well as it stood for a transition to a post-industrial radical right symbolized by the rise of Front National.Ordre Nouveau fut le principal mouvement néofasciste français de l’après-1945. Son histoire ne dure pas plus de quatre ans (1969-1973) mais elle témoigna d’une série de basculements et d’oscillations travaillant l’extrême droite. Se définissant avant tout tel un parti révolutionnaire et insufflant aux militants cette identité, Ordre Nouveau n’en collabora pas moins avec les instances de l’État alors en lutte contre le gauchisme. Le mouvement oscilla également, suivant le modèle à succès du MSI italien, entre un activisme médiatisé et identitaire, qui le mena à sa dissolution en 1973, et l’acceptation du jeu électoral pour lequel il fonda le Front National. Sa disparition signa à la fois la fin des rêves de droite révolutionnaire soutenue par des minorités agissantes usant de la violence politique et le passage à une extrême droite post-industrielle symbolisée par la montée en puissance du Front National.Ordre Nouveau fut le principal mouvement néofasciste français de l’après-1945. Son histoire ne dure pas plus de quatre ans (1969-1973) mais elle témoigna d’une série de basculements et d’oscillations travaillant l’extrême droite. Se définissant avant tout tel un parti révolutionnaire et insufflant aux militants cette identité, Ordre Nouveau n’en collabora pas moins avec les instances de l’État alors en lutte contre le gauchisme. Le mouvement oscilla également, suivant le modèle à succès du MSI italien, entre un activisme médiatisé et identitaire, qui le mena à sa dissolution en 1973, et l’acceptation du jeu électoral pour lequel il fonda le Front National. Sa disparition signa à la fois la fin des rêves de droite révolutionnaire soutenue par des minorités agissantes usant de la violence politique et le passage à une extrême droite post-industrielle symbolisée par la montée en puissance du Front National

Dorsal and ventral stimuli in cell–material interactions: effect on cell morphology

Cells behave differently between bidimensional (2D) and tridimensional (3D) environments. While most of the in vitro cultures are 2D, most of the in vivo extracellular matrices are 3D, which encourages the development of more relevant culture conditions, seeking to provide more physiological models for biomedicine (e.g., cancer, drug discovery and tissue engineering) and further insights into any dimension-dependent biological mechanism. In this study, cells were cultured between two protein coated surfaces (sandwich-like culture). Cells used both dorsal and ventral receptors to adhere and spread, undergoing morphological changes with respect to the 2D control. Combinations of fibronectin and bovine serum albumin on the dorsal and ventral sides led to different cell morphologies, which were quantified from bright field images by calculating the spreading area and circularity. Although the mechanism underlying these differences remains to be clarified, excitation of dorsal receptors by anchorage to extracellular proteins plays a key role on cell behavior. This approach—sandwich-like culture—becomes therefore a versatile method to study cell adhesion in well-defined conditions in a quasi 3D environment

Characterization of an internal slope movement structure by hydrogeophysical surveying

International audienceA hydrogeophysical study was carried out by a water controlled injection within a landslide situated on an active part of the La Clapière landslide foot (Alpes Maritimes, France). Coupling of both real-time geophysical and hydrological follow ups allowed the representation and quantification of the surface water drainage in space and time within the slipped mass. Thus, 30% of the injected water is quickly drained by a complex slipping surface meanly situated at 10-m depth. The transit time between injection and outflow of the water allowed an overloading of about 10 m3 (i.e. 10 tons) comparable with classical rain events in the area. This weight and the associated interstitial pressures increase have not led to any movements asking for the origin of the water volumes which could induce destabilizations. This experiment enabled an accurate redefinition of the internal slope structure and the understanding of the dynamics of the slipped mass with a surface hydraulic request

La représentation des Aborigènes dans les illustrations des livres écrits pour la jeunesse australienne entre 1830 et 1930 : une vision entre mythe et réalités

Les illustrations mettant en scène des Aborigènes dans les ouvrages de littérature jeunesse australiens ont participé activement à la création d'un imaginaire stéréotypé et à la représentation d'une altérité qui intrigue et est parfois menaçante. Cet article vient confirmer que l’étude de ces stéréotypes dans les illustrations et leur portée sur le lecteur sont autant d’éléments à prendre en compte pour mettre en lumière les implications idéologiques souvent sous jacentes dans les ouvrages pour la jeunesse et pour tenter de comprendre l’évolution des relations interraciales en Australie.The illustrations representing Indigenous Peoples in Australian children’s books took an active part in creating a stereotyped imaginary and an intriguing and threatening image of the Other. This paper confirms that studying the stereotypes present in these illustrations and their impact on the reader is essential to understand the underlying ideologies books for children tried to convey and the evolution of interracial relationships in Australia

In vitro mechanical fatigue behavior of poly-ε-caprolactone macroporous scaffolds for cartilage tissue engineering: Influence of pore filling by a poly(vinyl alcohol) gel

Polymeric scaffolds used in regenerative therapies are implanted in the damaged tissue and subjected to repeated loading cycles. In the case of articular cartilage engineering, an implanted scaffold is typically subjected to long term dynamic compression. The evolution of the mechanical properties of the scaffold during bioresorption has been deeply studied in the past, but the possibility of failure due to mechanical fatigue has not been properly addressed. Nevertheless, the macroporous scaffold is susceptible to failure after repeated loading-unloading cycles. In this work fatigue studies of polycaprolactone scaffolds were carried by subjecting the scaffold to repeated compression cycles in conditions simulating the scaffold implanted in the articular cartilage. The behaviour of the polycaprolactone sponge with the pores filled with a poly(vinyl alcohol) gel simulating the new formed tissue within the pores was compared with that of the material immersed in water. Results were analyzed with Morrow’s criteria for failure and accurate fittings are obtained just up to 200 loading cycles. It is also shown that the presence of poly(vinyl alcohol) increases the elastic modulus of the scaffolds, the effect being more pronounced with increasing the number of freeze/thawing cycles.This work is funded by FEDER funds through the "Programa Operacional Fatores de Competitividade – COMPETE" and by national funds arranged by FCT- Fundação para a Ciência e a Tecnologia, project reference PEST-C/FIS/UI607/2011. The authors also thank funding from Matepro –Optimizing Materials and Processes”, ref. NORTE-07-0124-FEDER000037”, co-funded by the “Programa Operacional Regional do Norte” (ON.2 – O Novo Norte), under the “Quadro de Referência Estratégico Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER). The authors also thank support from the COST Action MP1206 “Electrospun Nano-fibres for bio inspired composite materials and innovative industrial applications” and MP1301 “New Generation Biomimetic and Customized Implants for Bone Engineering”. JAP and VS thank the FCT for the SFRH/BD/64586/2009 and SFRH/BPD/63148/2009 grants, respectively. JLGR acknowledge the support of the Spanish Ministry of Science and Innovation through project No. MAT2010-21611-C03-01 (including the FEDER financial support). CIBER-BBN is an initiative funded by the VI National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund

Geophysical survey to estimate the 3D sliding surface and the 4D evolution of the water pressure on part of a deep seated landslide

International audienceGeophysical surveys were conducted on the very unstable front part of the La Clapière landslide in the French Alps (Alpes Maritimes). The electrical resistivity survey was carried out to obtain, for the first time on this deep-seated landslide, 3D information on the slipping surface and the vertical drained faults. Moreover, we planned to follow within time (6 months) the evolution of the saturated zones (presence of gravitational water) and their percolation into the shearing zones. Our 4D results showed the importance of the complex water channelization within the slope and relation to geological discontinuities

Anticoagulation loco-régionale par l utilisation d un dialysat au citrate sans calcium en hémodialyse chronique

Introduction : L anticoagulation régionale au citrate (RCA) est une alternative à la dialyse sans héparine. Sa mise en oeuvre reste difficile en hémodialyse chronique (HD). Matériels et Méthodes Cette étude de faisabilité décrit une technique de RCA simplifiée. Elle utilise un dialysat au citrate sans calcium : le transfert diffusif de citrate du dialysat vers le sang permet de s'affranchir de l injection de citrate sur la ligne artérielle. La quantité de calcium à injecter sur la ligne veineuse est déterminée précisément en temps réel (modélisation cinétique) en fonction des valeurs mesurées de dialysance ionique. Cinquante séances en RCA (QB 300, 350 et 400 mL/min) et 27 séances contrôles (HD conventionnelle avec héparine) sont réalisées chez 17 patients. L objectif primaire est de déterminer le taux de succès de la technique (pourcentage de séances menées à terme sans coagulation du circuit de dialyse). Résultats Le taux de succès est de 98% (49 des 50 séances). Toutes les calcémies ionisées (iCa) en sortie de dialyseur sont inférieures à 0,4 mM (seuil pour obtenir une anticoagulation efficace). Les iCa du patient augmentent de 1,00+-0,08 à 1,16+-0,10 mM pendant la séance (valeurs extrêmes de iCa mesurées sur l'étude [0,94-1,38 mM]). Les citratémies augmentent pendant la séance (de 13,4+-13,4 à 52,9+-38,9 M, p<0,001). Aucun effet secondaire du citrate n est observé. Le pH augmente (de 7,43+-0,05 à 7,50+-0,05, p<0,001) ainsi que la bicarbonatémie (de 19,9+-2,34 à 24,9+-2,53 mM, p<0,001) sans alcalose sévère observée. Les paramètres de coagulation au cours des séances en RCA ne sont pas différents de ceux observés au cours des séances contrôles. L augmentation de la iCa du patient pendant la séance est similaire dans les 2 groupes. Aucune différence n est notée sur les paramètres d épuration. Discussion et Conclusion Cette technique originale de RCA est efficace et fiable. L asservissement automatique de la réinjection de calcium à la dialysance ionique permettrait sa réalisation en routine.ROUEN-BU Médecine-Pharmacie (765402102) / SudocSudocFranceF

Effects of hydroxyapatite filler on long-term hydrolytic degradation of PLLA/PCL

[EN] Poly(L-lactic acid)(PLLA)/poly(epsilon-caprolactone)(PCL)/hydroxyapatite(HAp) composites appear as promising materials for healing large bone defects. Highly porous PLLA/PCL scaffolds, 80/20, 20/80 weight ratios, porosity >85%, were prepared by a dual technique of freeze extraction and porogen leaching, with and without HAp. A double pore structure was obtained, with interconnected macroporosity together with interconnected microporosity. Subsequent long-term (78 weeks = 1.5 years) hydrolytic degradation behavior was investigated in terms of the samples' mechanical properties, molecular weight (M-w), mass changes, thermal characteristics, X-ray Diffraction and Thermogravimetric Analysis. Elastic modulus and yield strength of as-synthesized scaffolds were higher for PLLA rich blends and including the inorganic phase does not lead to a mechanical strengthening in these materials. Nevertheless, after 30 weeks of degradation, PLLA rich scaffolds lost more than half of their strength and rigidity. On the contrary, the densification modulus of the PLLA based blends increased with degradation time, whereas PCL-based blends had a relatively constant densification modulus. PCL-based samples showed lower hydrolysis coefficients k than PLLA-based samples, as expected from the higher density of ester bonds in the latter. Interestingly, although including HAp leads to a lower hydrolysis coefficient k in PCL rich samples, it increases k in the PLLA-based sample, which is consistent with the other results obtained.The authors are grateful for the support of the Biomedical Research Networking Center in Bioengineering, Biomaterials, and Nanomedicine, an initiative funded by the VI National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, and Consolider Program. J. Rodenas-Rochina acknowledges the funding of his PhD by the Valencian Generality through VALi+d grant.Ródenas Rochina, J.; Vidaurre, A.; Castilla Cortázar, MIC.; Lebourg ., MM. (2015). Effects of hydroxyapatite filler on long-term hydrolytic degradation of PLLA/PCL. Polymer Degradation and Stability. 119:121-131. doi:10.1016/j.polymdegradstab.2015.04.01512113111