Multiscale dynamics of 1H and 19F in confined ionogels for lithium batteries

International audienceWe present the first results of the nuclear magnetic relaxation dispersion (NMRD) of the confined proton-bearing cation (BMI) and fluorine-bearing anion (TFSI) pair of ionic liquids (Li+-ionogels) confined within a silica-like mesoporous matrices designed for lithium batteries. These results are in favour of a very-correlated dynamical motion of the anion-cation pair within the solid and disordered silica matrix. (C) 2009 Academie des sciences. Published by Elsevier Masson SAS

NMR control of aging and durability of hardened cement pastes

Brownian dynamics of water confined in AOT reverse micelles: A field-cycling deuteron NMR relaxometry study

Perspectives in 1H, 14N and 81Br solid-state NMR studies of interfaces in materials textured by self-assembled amphiphiles

International audience1H solid-state NMR is becoming a routine characterisation tool. In the case of materials textured by self-assembled amphiphile molecules, we present a multi-scale characterisation approach, which can be easily implemented in most recent spectrometers. Valuable information on the interfaces between amphiphile molecules and oxide-based networks is obtained through this approach, as shown in some selected examples: block copolymers, hybrid siloxane membranes, and mesoporous microspheres obtained from spray-drying. We also present new results on 14N and 81Br solid-state NMR and discuss the applicability of direct or indirect proton-detected experiments to the study of mesoporous materials textured by cationic surfactants

Capsule motion in flow: Deformation and membrane buckling

Decomposition of shell deformations – Asymptotic behavior of the Green–St Venant strain tensor

Vertical movements at the fringe of the West African Craton: First zircon fission track datings from the Anti-Atlas Precambrian basement, Morocco

Emergence of infectious diseases: when hidden pathogens break out

Our understanding of disease emergence is largely limited by the assumption that disease emergence is the result of increased exposure to pathogenic agents. Pathogen exposure is thought to arise through an increase in the number of interactions between humans and their natural environment, changes in demography and mobility, or through genetic variation in the infectious agents which may alter virulence or ability to infect new host species. The study of new diseases (which are often revealed by unusually severe symptoms or atypical epidemiological patterns) applies the most effort to the research of new pathogens. Here, using examples, we discuss alternative but non-exclusive mechanisms that may either reveal the presence of long-term circulating pathogens or explain changes in their nosologic properties in relation to their pattern of circulation and infection conditions. A better understanding of the ecology of pathogenic organisms and their host populations should help to define more efficient health management strategies.

An integrative genomics approach for deciphering the complex interactions between ascorbate metabolism and fruit growth and composition in tomato

Very few reports have studied the interactions between ascorbate and fruit metabolism. In order to get insights into the complex relationships between ascorbate biosynthesis/recycling and other metabolic pathways in the fruit, we undertook a fruit systems biology approach. To this end, we have produced tomato transgenic lines altered in ascorbate content and redox ratio by RNAi-targeting several key enzymes involved in ascorbate biosynthesis (2 enzymes) and recycling (2 enzymes). In the VTC (ViTamin C) Fruit project, we then generated phenotypic and genomic (transcriptome, proteome, metabolome) data from wild type and mutant tomato fruit at two stages of fruit development, and developed or implemented statistical and bioinformatic tools as a web application (named VTC Tool box) necessary to store, analyse and integrate experimental data in tomato. By using Kohonen's self-organizing maps (SOMs) to cluster the biological data, pair-wise Pearson correlation analyses and simultaneous visualization of transcript/protein and metabolites (MapMan), this approach allowed us to uncover major relationships between ascorbate and other metabolic pathways.

A wavelet-based parameterization for speech/music discrimination

International audienceThis paper addresses the problem of parameterization for speech/music discrimination. The current successful parameterization based on cepstral coefficients uses the Fourier transformation (FT), which is well adapted for stationary signals. In order to take into account the non stationarity of music/speech signals, this work proposes to study wavelet-based signal decomposition instead of FT. Three wavelet families and several numbers of vanishing moments have been evaluated. Different types of energy, calculated for each frequency band obtained from wavelet decomposition, are studied. Static, dynamic and long-term parameters were evaluated. The proposed parameterization are integrated into two class/non-class classifiers: one for speech/non-speech, one for music/non-music. Different experiments on realistic corpora, including different styles of speech and music (Broadcast News, Entertainment, Scheirer), illustrate the performance of the proposed parameterization, especially for music/non-music discrimination. Our parameterization yielded a significant reduction of the error rate. More than 30% relative improvement was obtained for the envisaged tasks compared to MFCC parameterization