RAFT/MADIX polymers for the preparation of polymer/inorganic nanohybrids

Organic–inorganic hybrid nanocomposites are an emerging class of materials that hold significant promise due to their outstanding properties, which usually arise from a combined and/or synergistic effect of the properties of their organic and inorganic components. Despite the numerous functionalization methods described in literature, only a few of them allow precise and easy control of the chemical composition and structure of the organic shell, whereas this point is critical to control some of the nanohybrids properties such as solubility, specific interaction and so forth. In this context, reversible addition-fragmentation chain transfer polymerization/macromolecular design by interchange of xanthates (RAFT/MADIX) technology is a fantastic tool that can be easily performed in mild and “green” conditions, being compatible with a huge variety of functional monomers and providing an excellent control of the organic shell characteristics. This review aims to describe the state of the art of the use of RAFT/MADIX polymers for the preparation of these nanohybrids. After describing the most commonly used synthetic strategies for nanohybrids preparation, the main families of polymers are discussed in view of their chemical composition (homopolymer, copolymer, …) and/or the targeted properties (hydrophilic, hydrophobic, stimuli-responsive). The main advantages of RAFT/MADIX technology are discussed in terms of the numerous applications of those materials.     

Discovery and biological activity of 6BrCaQ as an inhibitor of the Hsp90 protein folding machinery

Heat shock protein 90 (Hsp90) is a significant target in the development of rational cancer therapy, due to its role at the crossroads of multiple signaling pathways associated with cell proliferation and viability. Here, a novel series of Hsp90 inhibitors containing a quinolein‐2‐one scaffold was synthesized and evaluated in cell proliferation assays. Results from these structure–activity relationships studies enabled identification of the simplified 3‐aminoquinolein‐2‐one analogue 2 b (6BrCaQ), which manifests micromolar activity against a panel of cancer cell lines. The molecular signature of Hsp90 inhibition was assessed by depletion of standard known Hsp90 client proteins. Finally, processing and activation of caspases 7, 8, and 9, and the subsequent cleavage of PARP by 6BrCaQ, suggest stimulation of apoptosis through both extrinsic and intrinsic pathways.     

A Method to Check and Discover Adulteration of Nebbiolo-Based Monovarietal Musts: Detection of Barbera and Dolcetto cv via SSR Analysis Coupled with Lab-On-Chip® Microcapillary Electrophoresis

The process of wine traceability/authentication is a key target for Italy, the world’s first largest wine producer (around 4.6 million tons in 2010 according to FAOSTAT). Several European countries developed appellation systems, with their own unique labels and seals, trying to fight label fraud that misrepresented the true origins of the wine. Advancements on this topic were provided by Council Regulation (EC) No. 479/2008 on the common organisation of the market in wine. As reported by experts, it is suspected that as much as 5 % of the wine sold in secondary markets worldwide could be counterfeit. Despite the high number of traceability methods, commonly based on the use of time consuming and expensive techniques (SNIF-NMR and stable isotope-ratio mass spectrometry), few applications report the use of polymerase chain reaction directly in musts or in bottled wine. Information on genetic polymorphism given by simple sequence repeats (SSR; microsatellite markers) proved helpful when applied to grape and musts analysis. The limited quantity of amplifiable grape genomic DNA in wine represents the main issue for the application of such analytical approach. Musts are the first intermediate product to be checked, in order to exclude the unintentional or fraudulent contamination with foreign grape varieties. The aims of this work are (1) the selection of performing SSR markers able to discriminate ‘Barbera’ and ‘Dolcetto’ from ‘Nebbiolo’ and (2) the hyphenated use of capillary micro-electrophoresis (lab-on-chip technology) for polymorphisms detection, to highlight the presence of foreign grape in ‘Nebbiolo’ musts produced in purity, as required by the designation disciplinary. Finally, we suggest using this approach by exploiting VVS2 marker in order to detect Barbera and Dolcetto grapes in Nebbiolo musts, waiting for more robust and powerful method to extract and amplify specific DNA from bottled wine.     

WorkSim: A Calibrated Agent-Based Model of the Labor Market Accounting for Workers’ Stocks and Gross Flows

This paper presents an agent-based model of the labor market. It simulates the market in the recent period at the aggregate level and at the level of the principal categories of labor, on the basis of the decisions of heterogeneous agents, firms and individuals, who interact. These decisions rely on individual computations of profits and utilities, although rationality is bounded in such a complex environment. The theoretical structure that underlies the decisions is the search concept. We apply this framework to the case of France in 2011. The model is at a scale of 1/4700. It is fairly detailed on the institutions of the labor market that constrain the agents’ decisions. Finally it is calibrated by a powerful algorithm to reproduce a large number of variables of interest. The calibrated model presents a consistent accounting system of the gross flows of the individuals between the main states, employment, distinguishing open ended contracts and fixed duration contracts, unemployment and inactivity. The simulation of the gross flows accounts enables us to analyze the patterns of mobility in a way that the observed statistics on gross flows, which are partial, cannot do. The model then characterizes the nature of the labor market under study, reproducing the high proportion of the fixed duration contracts in the hiring flows, and it points to a dualism of the French labor market.     

Molecular weight-viscosity relationship for amylopectin,a highly branched polymer

Summary Rate of acid hydrolysis of amylopectin is discussed from molecular weight variation; a two step mechanism is found. The highly branched amylopectin fractions obtained by partial acid hydrolysis allow experimental determination of Mark-Houwink's law exponents. Theoretical and experimental a values are compared.Laboratoire Propre du C.N.R.S., associé à l'Université Scientifique et Médicale de Grenoble     

Laser-Ultrasonics: From the Laboratory to the Shop Floor

Ultrasonics is a powerful technique for inspecting and characterizing industrial materials. It not only can detect bulk and surface flaws, but also obtain information on material microstructure, which determines engineering properties, such as elastic moduli and ultimate strength. However, traditional ultrasound requires liquid or contact coupling for its generation and detection, making it difficult or impossible to apply in many industrial situations. This occurs, in particular, on curved parts and on parts at elevated temperature, a situation widely found in industrial products and during the processing of industrial materials.Through a continuing effort that started more than 10 years ago, the Industrial Materials Institute of the National Research Council of Canada working in collaboration with UltraOptec Inc. has developed a technique called laser-ultrasonics, that circumvents the limitations of the conventional techniques. This novel technique is based on the generation and detection of ultrasound with lasers. The technology we have developed has been demonstrated to be applicable to real industrial conditions. In particular, a system was brought to a steel mill to measure on-line the wall thickness of tubes at 1000°C moving at 4 m/s. The capability of our technology to inspect advanced aircrafts made of composite materials was also demonstrated by inspecting a CF-18 in the hangar of a maintenance facility. UltraOptec Inc. is now in the process of commercializing this technology, in particular, for these two demonstrated industrial applications.     

Gel permeation chromatography of the xanthan gum using a light scattering detector

Summary This work gives the first gel permeation chromatogramms obtained on native xanthan using a refractometric and a light scattering detectors. Results of molecular weights distribution analysis give a polydispersity 1.2 for the native polymer and 1.7 for enzymic partially degraded polymer. The experimental conditions and chromatogramms interpretation are briefly discussed.Laboratoire Propre de C.N.R.S., associé à l'Université Scientifique et Médicale de Grenoble     

Improving the readability of clustered social networks using node duplication

Exploring communities is an impor tant task in social network analysis. Such communities are currently identified using clustering methods to group actors. This approach often leads to actors belonging to one and only one cluster, whereas in real life a person can belong to several communities. As a solution we propose duplicating actors in social networks and discuss potential impact of such a move. Several visual duplication designs are discussed and a controlled experiment comparing network visualization with and without duplication is performed, using 6 tasks that are impor tant for graph readability and visual interpretation of social networks. We show that in our experiment, duplications significantly improve community-related tasks but sometimes interfere with other graph readability tasks. Finally, we propose a set of guidelines for deciding when to duplicate actors and choosing candidates for duplication, and alternative ways to render them in social network representations.