Synthesis and characterization of polymers for nonlinear optical applications

International audienceA difunctional NLO Azo-Dye chromophore has been synthesized and polymerization has been performed with a comonomer bearing a side-chain epoxy group. Deposition of the polymer on glass substrates was performed by spin-coating, resulting in uniform films up to 2 µm thickness. The orientation of the chromophore was performed under a " pin-to-plane " positive corona discharge followed by a heat-treatment in order to obtain reticulation of the films. Molecular orientation has been investigated using UV-Vis. and Raman spectroscopy. Poling of the films results in a decay of absorbency as well as in a blue shift of the spectrum. At the same time, the 1600 cm-1 band disappears from the Raman spectra, indicating orientation of the chromophores. Cross-linking has been studied by FTIR and all-optical poling and showed an improved stability of the electro-optic thin films

Psychologie générale

Lécuyer Roger, Perruchet Pierre, Launay Michel, Jacobs A., Piéraut-Le Bonniec Gilberte, Moscato Michel, Le Ny J.-F., Zubizarreta M. L. Psychologie générale. In: L'année psychologique. 1985 vol. 85, n°2. pp. 276-290

Psychologie générale

Lécuyer Roger, Perruchet Pierre, Launay Michel, Jacobs A., Piéraut-Le Bonniec Gilberte, Moscato Michel, Le Ny J.-F., Zubizarreta M. L. Psychologie générale. In: L'année psychologique. 1985 vol. 85, n°2. pp. 276-290

Accelerated aging and life tests of optical fibers

The reliability of the network optical fibers is a critical issue for telecommunications.New investigations methods have been developed within a cooperative program supported by France Telecom. They include low coherence interferometry and optical near field microscopy in association with classical analysis tools such as Scanning Electron Microscopy and Shear Force Microscopy. One aim of the study is the localization and the characterization of the defects from which failure originates. The aging effect has been investigated in silica fibers immersed in desionized water at 65 oc and 85 "C for different times: from 3 to 12 month

Genome-wide measures of DNA methylation in peripheral blood and the risk of urothelial cell carcinoma: a prospective nested case-control study

BACKGROUND: Global DNA methylation has been reported to be associated with urothelial cell carcinoma (UCC) by studies using blood samples collected at diagnosis. Using the Illumina HumanMethylation450 assay, we derived genome-wide measures of blood DNA methylation and assessed them for their prospective association with UCC risk. METHODS: We used 439 case–control pairs from the Melbourne Collaborative Cohort Study matched on age, sex, country of birth, DNA sample type, and collection period. Conditional logistic regression was used to compute odds ratios (OR) of UCC risk per s.d. of each genome-wide measure of DNA methylation and 95% confidence intervals (CIs), adjusted for potential confounders. We also investigated associations by disease subtype, sex, smoking, and time since blood collection. RESULTS: The risk of superficial UCC was decreased for individuals with higher levels of our genome-wide DNA methylation measure (OR=0.71, 95% CI: 0.54–0.94; P=0.02). This association was particularly strong for current smokers at sample collection (OR=0.47, 95% CI: 0.27–0.83). Intermediate levels of our genome-wide measure were associated with decreased risk of invasive UCC. Some variation was observed between UCC subtypes and the location and regulatory function of the CpGs included in the genome-wide measures of methylation. CONCLUSIONS: Higher levels of our genome-wide DNA methylation measure were associated with decreased risk of superficial UCC and intermediate levels were associated with reduced risk of invasive disease. These findings require replication by other prospective studies