Effects of dynamic cell culture conditions on 3D spatial reogarnization of MSCS/HUVECS spheroids in the context of bone tissue

We aim to observe the development and reorganization of MSCs and HUVECs in Pullulan/Dextran hydrogels supplied with nHAp under dynamic culture conditions in a perfusion bioreactor.Hydrogel poreux sous perfusion : modélisation et optimisation d'un modèle in vitro de reconstruction de défaut osseu

P19 - Imagerie chimique de la paroi de bois au niveau subcellulaire en microscopie confocale et micro-spectrométrie confocale Raman

International audienc

Old English lyrics. Lovely kind and kindly loving

For high voice and piano. --- At head of title: Two old English lyrics. --- Words printed also as text on p. [3]

Architecture and physiology of microalgae biofilms

International audienceMicroalgae biofilms have a great ecological importance and a high biotechnological potential. Nevertheless, an in-depthand combined structural (i.e. the architecture of the biofilm) andphysiological characterization of microalgaebiofilmsis still missing.An approach able to provide at the same time physiological and structuralinformation during biofilm growth would be of paramount importance to understand these complex biological systemsand to optimize their productivity.In this study, monospecific biofilmsof a diatom and a green algawere grownunder dynamic conditionsin custom flow cells represented by UV/Vis spectroscopic cuvettes. Such flow cells wereconceivedto characterize the biofilms by severaltechniquesmostlyin situand in a non-destructive way.Physiological traitswere obtained measuring variable chlorophyll afluorescence by pulse amplitude modulated fluorometry (PAM) and by scanning the biofilms in a spectrometer to obtain in vivopigments spectral signatures. The architectural features were obtained by imaging the biofilms with a confocal scanning laser microscope(CLSM)and anoptical coherence tomograph(OCT).Overall,this experimental setup allowed us to follow the growth of two biofilm-forming microalgae showing thatcell physiology is more affected in complex biofilms likely as a consequence of alterations in local environmental conditions

Shear stress affects the architecture and cohesion of Chlorella vulgaris biofilms

International audienceThe architecture of microalgae biofilms has been poorly investigated, in particular with respect toshear stress, which is a crucial factor in biofilm-based reactor design and operation. To investigatehow microalgae biofilms respond to different hydrodynamic regimes, the architecture and cohesionof Chlorella vulgaris biofilms were studied in flow-cells at three shear stress: 1.0, 6.5 and 11.0 mPa.Biofilm physical properties and architecture dynamics were monitored using a set of microscopictechniques such as, fluorescence recovery after photobleaching (FRAP) and particle tracking. At lowshear, biofilms cohesion was heterogeneous resulting in a strong basal (close to the substrate) layerand in more loose superficial ones. Higher shear (11.0 mPa) significantly increased the cohesion ofthe biofilms allowing them to grow thicker and to produce more biomass, likely due to a biologicalresponse to resist the shear stress. Interestingly, an acclimation strategy seemed also to occurwhich allowed the biofilms to preserve their growth rate at the different hydrodynamic regimes. Ourresults are in accordance with those previously reported for bacteria biofilms, revealing some generalphysical/mechanical rules that govern microalgae life on substrates. These results may bring newinsights about how to improve productivity and stability of microalgae biofilm-based systems

Tafassasset: Evidence of early incipient differentiation on a metal-rich chondritic parent body

Tafassasset is a primitive meteorite, the origin of which is still debated. Its possible relationship to either the CR chondrites - considered among the most primitive meteorites - or the brachinites - complex primitive achondrites - makes it an interesting sample for studying the initial stages of planetary accretion and differentiation in the early solar system. Here, we report tungsten (W) isotope data for bulk rock samples as well as for mineral fractions from Tafassasset, along with micro-computed tomography of a piece of the meteorite. Silicates show mass-independent W isotope anomalies, while the metal phase does not. These nucleosynthetic anomalies are interpreted as reflecting the presence of SiC presolar grains in the matrix of the meteorite, carrying s-process W-184 After correction of the nucleosynthetic anomalies, a correlation is observed between the W-182/W-184 isotope compositions and the Hf/W ratios of the different fractions. A Hf-182-W-182 age of ca. 2.9 Ma after CAIs is inferred from the Hf-182-W-182 chronometer, slightly older than other estimates based on the Mn-53-Cr-53, Al-26-Mg-26, and Pb/Pb chronometers, but consistent with the difference in closure temperatures of the different isotopic systems. Numerical modeling of the thermal evolution of Tafassasset indicates accretion of a parent-body less than similar to 50 km in diameter, = 1 Ma after the formation of CAIs, at a time when short-lived radio-nuclides induced metal-silicate separation and partial melting of the silicates with extraction of a basaltic component. According to our new data, Tafassasset may represent an inner part of a CR-like parent body, with a differentiation history similar to, but less severe than, that of brachinites. (C) 2015 Elsevier B.V. All rights reserved