Oxidative DNA damage is continuously generated in cells as a consequence of oxidative stress and this phenomenon is associated with several pathologic disorders. Generated reactive oxygen species could react with biological molecules including DNA the molecule bearing the genetic information. Cells have developed very efficient repair systems in order to minimise the biological consequences of such DNA lesions, among them, the base excision repair (BER) mechanism is known to be involved in the repair of oxidatively generated DNA lesions. In spite of the extensive work that has been done both on the formation and repair of oxidatively generated DNA lesions, recent results suggest that a high proportion of so-called tandem lesions, constituted of two (or even more) lesions closely localised on the DNA could be produced as a consequence of a single ionisation process. Moreover, preliminary results indicate that these lesions that could be produced at a high ratio compared to single lesions, are less efficiently repaired by BER. The aim of our project is to study in more details the formation, repair and biological consequences of such tandem lesions compared to single damage. The formation of such damage will be evaluated using oligonucleotides containing a photochemical precursor of DNA radicals. Generated lesions produced upon photolysis of the oligonucleotide will be identified and quantified using physico-chemical approaches. Thereafter, identified damage will be incorporated into oligonucleotide that will be used to study the repair efficacy of such damage by both DNA glycosylases and cells extracts. To better understand how the presence of a second lesion could affect the repair capacity of a defined enzyme, efforts will be made to visualize the effect of these lesions on the local structure of duplex DNA-glycosylase complexes. In parallel, affinity constant and kinetics of excision of the tandem lesions will be determined and compared to single isolated damage. Finally, the mutagenic properties of the tandem lesions will be also determined upon transfection in cells. The originality of the project is to bring together chemists, structural biologists, biochemists and cellular biologists to determine, by the use complementary approaches, the relevance and biological consequences of a defined type of DNA damage that has not yet been studied previously. Preliminary results obtained very recently strongly suggest that the tandem lesions that will be studied most probably play an important role in the harmful effect of endogenous oxidative stress that is associated to several human pathologies.

Plasmonic structures confine light in optical waveguides and resonators with sub-wavelength dimensions and are more compact than dielectric or semiconductor ones. Metallic structures concentrate optical field in visible or near infrared wavelength at a few nanometer scale where as optical modes in dielectric or resonators semiconductor-air have typical length of a few hundred nanometer. After the first research on isolated metallic nanostructures, the plasmonic community is focused on metallic integrated optical structures for sub wavelength devices. As an example, very compact structures wit T or L shape has been proposed using metallic nanostructures chains (optical guides with localised plasmons). These chains can be realized by nanotechnology on semiconductor substrate. The interest of these metallic integrated structures, as already mentioned is to reach an order of magnitude in the miniaturization of integrated photonic circuits. They allow to redirect light with arbitrary angle or to increase the density the optical waveguides in 2d without lateral coupling and cross talk between these guides. In this context, the object and originality at international level of the PLACIDO project is to study and realize the coupling between optical SOI and plasmonic waveguides, in particular chains of coupled gold nanostructures. It will also explore optical transmission on an extended wavelength range (1150-1600 nm), which allows addressing several potential applications: biological sensors, integrated and miniaturized photonic circuits at telecom wavelength. An other original aspect is the characterization and optimization methodology, based on experimental near field mapping of propagating electromagnetic fields along these structures by scanning near field optical probe with phase resolution. This experimental technique allows precise and direct experimental analysis of coupling mechanism with sub- wavelength spatial resolution. The proposal is organised in such way to focus on realization and optimisation of coupling between SOI and plasmonic waveguides. It organize around three tasks strongly linked : nanotechnology, conception and modelling, guided and near-field optical characterization. The first step will be focused on the technological realization of plasmonic waveguides on SOI. The second step will develop transition and coupling studies between SOI and plasmonic waveguides, supported by two complete cycles of conception-realization-characterization. At the end, the test of a two branches light plasmonic distributor on SOI substrate using TE or TM mode will validate the integrated concepts developed in this proposal.

The technology growth of carbon nanotubes on the surface of fiber by catalytic vapor deposition is now fairly well controlled at the level of research laboratories and some applications are already under consideration at industrial level. These nanomaterials have an industrial interest by improving mechanical, electrical and thermal composite properties. But industry remains the stumbing block concerning the safe use of this type of hybrid fiber. Indeed so far there is no guarantee to preserve the totality of carbon nanotubes on the surface of the fiber during its implementation (weaving, impregnation). PROCOM therefore seeks to develop a continuous surface treatment in these nanotubes to keep them on the fibre while retaining the initial properties of the hybrid fiber. The surface treatment will include an original concept of tracer combined with its detection system in order to monitor the quality of manufacturing and inspection in the process of being implemented. The development imagined in PROCOM is a continuous manufacturing process controlled from the original fiber to fiber hybrid surface treated. The pilot developed will be implemented on a chain to show pre-industrial level of maturity