Scalable and Secure Aggregation in Distributed Networks

We consider the problem of computing an aggregation function in a \emph{secure} and \emph{scalable} way. Whereas previous distributed solutions with similar security guarantees have a communication cost of $O(n^3)$, we present a distributed protocol that requires only a communication complexity of $O(n\log^3 n)$, which we prove is near-optimal. Our protocol ensures perfect security against a computationally-bounded adversary, tolerates $(1/2-\epsilon)n$ malicious nodes for any constant $1/2 > \epsilon > 0$ (not depending on $n$), and outputs the exact value of the aggregated function with high probability

Scalable and Secure Aggregation in Distributed Networks

We consider the problem of computing an aggregation function in a \emph{secure} and \emph{scalable} way. Whereas previous distributed solutions with similar security guarantees have a communication cost of $O(n^3)$, we present a distributed protocol that requires only a communication complexity of $O(n\log^3 n)$, which we prove is near-optimal. Our protocol ensures perfect security against a computationally-bounded adversary, tolerates $(1/2-\epsilon)n$ malicious nodes for any constant $1/2 > \epsilon > 0$ (not depending on $n$), and outputs the exact value of the aggregated function with high probability

Use of reconstituted metabolic networks to assist in metabolomic data visualization and mining

Metabolomics experiments seldom achieve their aim of comprehensively covering the entire metabolome. However, important information can be gleaned even from sparse datasets, which can be facilitated by placing the results within the context of known metabolic networks. Here we present a method that allows the automatic assignment of identified metabolites to positions within known metabolic networks, and, furthermore, allows automated extraction of sub-networks of biological significance. This latter feature is possible by use of a gap-filling algorithm. The utility of the algorithm in reconstructing and mining of metabolomics data is shown on two independent datasets generated with LC–MS LTQ-Orbitrap mass spectrometry. Biologically relevant metabolic sub-networks were extracted from both datasets. Moreover, a number of metabolites, whose presence eluded automatic selection within mass spectra, could be identified retrospectively by virtue of their inferred presence through gap filling

Linge opératoire en nontissé (étude technique au CHU de Toulouse)

La réflexion normative en cours (pr EN 13795 ; pr EN ISO 22612 et 22610) sur les nontissés à usage médical ; l'évolution des procédés de fabrication et des fibres constitutives de ces produits nous ont conduits à réaliser une étude technique. Nous avons testé la résistance à la pénétration du sang humain sous pression et la perméabilité des principaux nontissés présent sur le marché français constitutifs de casaques et de champs opératoires. De plus nous avons comparé leur pouvoir absorbants. Nos résultats ont retrouvé une résistance au passage du sang très variable d'un tissé à l'autre : les SMS et SMMS présentent une meilleure résistance que les spunlace alors qu'ils sont tous perméables à l'air. L'absorption quant à elle est très variables selon les produits. La particularité de chaque non-tissé a conduit les laboratoires à développer différents concepts selon les propriétés de leur nontissé et le type d'intervention (" sèche " ou " humide "). A ce jour le nontissé idéal n'existe pas, le choix du linge opératoire reste un compromis entre le type d'intervention, le degré de protection souhaité et le confort du malade et de l'équipe soignante.TOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE3-BU Santé-Allées (315552109) / SudocSudocFranceF

Highly Dynamic Distributed Computing with Byzantine Failures

International audienc

Single-Molecule Force Spectroscopy on Synthetic Helical Nanoarchitectures

Foldamers are artificial folded molecular architectures inspired by the structures and functions of natural biopolymers. Folding is the process selected by nature to control the conformation of its molecular machinery to carry out chemical functions and mechanical tasks, such as en-zyme catalysis, duplication in nucleic acids, force generation,... During the last decade of research on foldamers [1], synthetic oligomers able to adopt well-defined and predictable folded conformations, such as helices, have been proposed. Recent progress has shown that stepwise chemical synthesis and molecular design based on aromatic oligoamide backbones enable to produce large helically folded molecular architectures. The shape and stiffness of the backbone, local conformational preferences, specific interactions between distant monomers in sequences, as well as the action of external parameters such as the solvent or the presence of ions, can be combine to induce folding tendency. A remarkable aspect of these architectures is that they can give rise to folded patterns that have no in natural counterparts biopolymer structures. For instance, helices whose diameter varies along the se-quence, helices possessing a handedness inversion centre, herringbone helices have been reported. The objective of the project is to synthesize various helical nanorchitectures based on an oli-goamide aromatic backbone and to obtain a detailed picture of their dynamical conformation in solution, as well as, their mechanochemical properties, by AFM-based single molecule force spectroscopy. It is worth mentioning that an important sub-objective of this project is to probe intramolecular interactions in small synthetic molecules with the AFM. Indeed, whereas single-molecule force spectroscopy on macromolecules (proteins and synthetic polymers) is widely exploited[2], implementing single-molecule force spectroscopy on small molecules, such as the foldamers proposed here, remains a major challenge[3]. [1] For a review, see G. Guichard and I. Huc, Chem. Commun. 2011, 47, 5933–5941. [2]E. M. Puchner, H. E.Gaub, Curr. Opin. Struct. Biol. 2009, 19, 605–614. [3]P. Lussis, A.-S. Duwez, Nature Nanotech. 2011, 6, 553-55

Single-Molecule Force Spectroscopy on Synthetic Helical Nanoarchitectures

Inspired by the many folded conformations of the molecular machineries in nature, chemists have been developing the syntheses of artificial folded molecular architectures, namely foldamers. The investigation of these molecules using AFM-based Single Molecule Force Spectrosocopy (SMFS) allows the elucidation of both mechanochemical properties and conformational dynamics on the unimolecular scale in solution. The stepwise synthesis of aromatic oligoamide-based foldamers was designed to produce well-defined helically-folded molecular architectures. A PEO tether was coupled to one end of the foldamer. SMFS pulling experiments on this system yielded specific and reproducible force-extension patterns characteristic of single foldamers. Those patterns were further analyzed to determine unfolding forces and dynamics as well as to propose mechanistics hypotheses of the unfolding process. Several helical foldamers presenting variable lengths were considered. The force values measured for those foldamers are higher than those previously measured in natural biopolymers showing a high stability under a load and a propensity for the development of emergent properties. In addition, the increased stability of these aromatic oligoamide foldamers was confirmed by the observation of almost instantaneous reversibility of the unfolding under load