Surface gas geochemistry above the natural CO2 reservoir of Montmiral (Drôme, France), source tracking and gas exchange between the soil, biosphere and atmosphere

International audienceOne of the options considered to mitigate greenhouse gas concentrations in the atmosphere is underground storage of CO2. There is a strong need for enhancing and developing methods that would help throughout the duration life of such underground storage, to ensure the safety and able to monitor the evolution of the injected CO2 plume. Among these, geochemical methods can play an important role. Here, we describe results acquired under the research programme “Géocarbone-Monitoring”, partially funded by the French National Research Agency, on the Montmiral natural analogue in South-Eastern France. Other results obtained under the same research programme in the French Massif Central are reported elsewhere in this volume.Spot sampling methods allowing a great geographical coverage and continuous measurements on selected points were undertaken in 2006 and 2007, in order to determine soil gas concentrations and fluxes as well as carbon isotope ratio determinations. One important result is that without any evidence of deep CO2 leakage, both CO2 concentrations and fluxes appear to be higher than can be explained only by biological activities. Further investigations are thus needed to understand the gas evolution better throughout the year

Ultrahigh Sensitivity Slot-Waveguide Biosensor on a Highly Integrated Chip for Simultaneous Diagnosis of Multiple

SABIO is a multidisciplinary project involving the emerging fields of micro-nanotechnology, photonics, fluidics and bio-chemistry, targeting a contribution to the development of intelligent diagnostic equipment through the demonstration of a compact polymer based and silicon-based CMOS-compatible micro-nano system. It integrates optical biosensors for label-free biomolecular recognition based on a novel photonic structure named slot-waveguide with immobilized bimolecular receptors on its surface. The slot-waveguides provide high optical intensity in a sub wavelength-size low refractive index region (slot-region) sandwiched between two high refractive index strips (rails) [1] leading to an enhanced interaction between the optical probe and biomolecular complexes (antibody-antigen). As such a biosensor is predicted to exhibit a surface concentration detection-limit lower than 1 pg/mm2, state-of-the-art in label free integrated optical biosensors, as well as the possibility of multiplexed assay, which, together with reduced reaction volumes, leads to the ability to perform rapid multi-analytesensing and comprehensive tests. This offers the further advantageous possibility of assaying several parameters simultaneously and consequently, statistical analysis of these results can potentially increase the reliability and reduce the measurement uncertainty of a diagnostic over single-parameter assays. In addition, the SABIO micro-nano system device applied to its novel protein-based diagnostic technology has the potential to be fast and easy to use, making routine screening or monitoring of diseases more cost-effective

Stem cell-derived astrocytes:are they physiologically credible?

Astrocytes are now increasingly acknowledged as having fundamental and sophisticated roles in brain function and dysfunction. Unravelling the complex mechanisms that underlie human brain astrocyte-neuron interactions is therefore an essential step on the way to understanding how the brain operates. Insights into astrocyte function to date, have almost exclusively been derived from studies conducted using murine or rodent models. Whilst these have led to significant discoveries, preliminary work with human astrocytes has revealed a hitherto unknown range of astrocyte types with potentially greater functional complexity and increased neuronal interaction with respect to animal astrocytes. It is becoming apparent, therefore, that many important functions of astrocytes will only be discovered by direct physiological interrogation of human astrocytes. Recent advancements in the field of stem cell biology have provided a source of human based models. These will provide a platform to facilitate our understanding of normal astrocyte functions as well as their role in CNS pathology. A number of recent studies have demonstrated that stem cell derived astrocytes exhibit a range of properties, suggesting that they may be functionally equivalent to their in vivo counterparts. Further validation against in vivo models will ultimately confirm the future utility of these stem-cell based approaches in fulfilling the need for human- based cellular models for basic and clinical research. In this review we discuss the roles of astrocytes in the brain and highlight the extent to which human stem cell derived astrocytes have demonstrated functional activities that are equivalent to that observed in vivo

All-sky Medium Energy Gamma-ray Observatory: Exploring the Extreme Multimessenger Universe

The All-sky Medium Energy Gamma-ray Observatory (AMEGO) is a probe class mission concept that will provide essential contributions to multimessenger astrophysics in the late 2020s and beyond. AMEGO combines high sensitivity in the 200 keV to 10 GeV energy range with a wide field of view, good spectral resolution, and polarization sensitivity. Therefore, AMEGO is key in the study of multimessenger astrophysical objects that have unique signatures in the gamma-ray regime, such as neutron star mergers, supernovae, and flaring active galactic nuclei. The order-of-magnitude improvement compared to previous MeV missions also enables discoveries of a wide range of phenomena whose energy output peaks in the relatively unexplored medium-energy gamma-ray band

Evolution morphosédimentaire de la plaine alluviale et aménagements anthropiques aux abords du sanctuaire-théâtre

International audienceLes investigations conduites aux abords du complexe monumental théâtre/sanctuaire d’Epomanduodurum (Mandeure–Mathay, Doubs) ont permis de mettre en évidence l’empreinte de plusieurs incisions mineures holocènes dans l’épanchement fluviatile de la basse terrasse würmienne Fy sur laquelle l’agglomération antique est en partie édifiée. La morphologie des lits fossiles repérés montre la coexistence de différents styles fluviaux. L’analyse du remplissage d’un des bras morts du Doubs a permis d’individualiser sept phases majeures d’évolution avec plusieurs remises en eau occasionnées par des crues plus ou moins importantes de la rivière. Des traces d’une occupation protohistorique pouvant être antérieures au IVème siècle ont été reconnues dans les couches supérieures scellant le comblement du chenal. Parallèlement, un ensemble de structures inédites (enceintes, temples, bâtiments, fosses et voies) a été détecté aux abords du complexe monumental par les prospections géophysiques. La nature de ces découvertes renouvelle complètement la perception de l’organisation spatiale des vestiges et le schéma de l’urbanisation de cette partie de l’agglomération antique

City map of ancient Epomanduodurum (Mandeure - Mathay, Franche-Comté, eastern France) : contribution of geophysical prospecting techniques.

International audienceThis study presents the main results of the geophysical survey of ancient Epomanduodurum, at Mandeure-Mathay, Eastern France. In northeastern Gaul, Epomanduodurum is a site of a major scientific interest for the understanding of past settlements and territorial formation at the end of the Iron Age and during the Roman period. The site, including a Roman urban centre and two suburbs containing workshops, occupies more than 500 ha inside and beyond a meander of the River Doubs. From the beginning of survey in 2001, several methods (fast electrical imaging automatic resistivity profiling system, ground penetrating radar, magnetic and electromagnetic mapping) have been performed on a large scale in order to precisely identify the vast extent and structure of the Roman town. The interpretation of the geophysical data was carried out using a combination of different data sources, including ancient maps and excavations recently conducted on restricted areas. The overall organization of an artisan quarter of 8 ha was revealed along a main Roman road leading to the left bank of the River Doubs. On the other bank, a river fortification and a vast monumental religious complex were recognized in the southern part of the Roman town. The geophysical imaging shows that the sacred area includes several temples or groups of temples radiating from the theatre. Other new buried structures probably corresponding to annexes, chapels and altars were also detected within this sacred area of 10 ha bound on three sides by a wall enclosure with monumental passages. In a surveyed area of 70 ha, geophysical prospecting techniques provided a clear overall image of the Roman urbanism revealed through a rectangular road network and street system delimiting insulae of variable sizes. The detection along the River Doubs of buildings similar to storehouses attests to fluvial transport and also suggests the likely existence of a port. More generally, the combination on a large scale of geophysical prospecting, aerial photographs and excavations allowed a new plan of the urban structure of the ancient town of Epomanduodurum to be produced for an area of over 300 ha

Central Mechanisms Mediating Thrombospondin-4-induced Pain States

Peripheral nerve injury induces increased expression of thrombospondin-4 (TSP4) in spinal cord and dorsal root ganglia that contributes to neuropathic pain states through unknown mechanisms. Here, we test the hypothesis that TSP4 activates its receptor, the voltage-gated calcium channel Ca-v alpha(2)delta(1) subunit (Ca-v alpha(2)delta(1)), on sensory afferent terminals in dorsal spinal cord to promote excitatory synaptogenesis and central sensitization that contribute to neuropathic pain states. We show that there is a direct molecular interaction between TSP4 and Ca-v alpha(2)delta(1) in the spinal cord in vivo and that TSP4/Ca-v alpha(2)delta(1)-dependent processes lead to increased behavioral sensitivities to stimuli. In dorsal spinal cord, TSP4/Ca-v alpha(2)delta(1)-dependent processes lead to increased frequency of miniature and amplitude of evoked excitatory post-synaptic currents in second-order neurons as well as increased VGlut(2)- and PSD95-positive puncta, indicative of increased excitatory synapses. Blockade of TSP4/Ca-v alpha(2)delta(1)-dependent processes with Ca-v alpha(2)delta(1) ligand gabapentin or genetic Ca-v alpha(2)delta(1) knockdown blocks TSP4 induced nociception and its pathological correlates. Conversely, TSP4 antibodies or genetic ablation blocks nociception and changes in synaptic transmission in mice overexpressing Ca-v alpha(2)delta(1). Importantly, TSP4/Ca-v alpha(2)delta(1)-dependent processes also lead to similar behavioral and pathological changes in a neuropathic pain model of peripheral nerve injury. Thus, a TSP4/Ca-v alpha(2)delta(1)-dependent pathway activated by TSP4 or peripheral nerve injury promotes exaggerated presynaptic excitatory input and evoked sensory neuron hyperexcitability and excitatory synaptogenesis, which together lead to central sensitization and pain state development

Central Mechanisms Mediating Thrombospondin-4-induced Pain States.

Peripheral nerve injury induces increased expression of thrombospondin-4 (TSP4) in spinal cord and dorsal root ganglia that contributes to neuropathic pain states through unknown mechanisms. Here, we test the hypothesis that TSP4 activates its receptor, the voltage-gated calcium channel Cavα2δ1 subunit (Cavα2δ1), on sensory afferent terminals in dorsal spinal cord to promote excitatory synaptogenesis and central sensitization that contribute to neuropathic pain states. We show that there is a direct molecular interaction between TSP4 and Cavα2δ1 in the spinal cord in vivo and that TSP4/Cavα2δ1-dependent processes lead to increased behavioral sensitivities to stimuli. In dorsal spinal cord, TSP4/Cavα2δ1-dependent processes lead to increased frequency of miniature and amplitude of evoked excitatory post-synaptic currents in second-order neurons as well as increased VGlut2- and PSD95-positive puncta, indicative of increased excitatory synapses. Blockade of TSP4/Cavα2δ1-dependent processes with Cavα2δ1 ligand gabapentin or genetic Cavα2δ1 knockdown blocks TSP4 induced nociception and its pathological correlates. Conversely, TSP4 antibodies or genetic ablation blocks nociception and changes in synaptic transmission in mice overexpressing Cavα2δ1 Importantly, TSP4/Cavα2δ1-dependent processes also lead to similar behavioral and pathological changes in a neuropathic pain model of peripheral nerve injury. Thus, a TSP4/Cavα2δ1-dependent pathway activated by TSP4 or peripheral nerve injury promotes exaggerated presynaptic excitatory input and evoked sensory neuron hyperexcitability and excitatory synaptogenesis, which together lead to central sensitization and pain state development