Plasmonic antennas for directional sorting of fluorescence emission

Spontaneous emission of fluorescent molecules or quantum dots is radiated along all directions when emitters are diluted in a liquid solution, which severely limits the amount of collected light. Besides, the emission direction does not carry any useful information and cannot be used to sort different molecules. To go beyond these limits, optical antennas have been recently introduced as conceptual tools to control the radiation properties for nanoemitters fixed on a substrate. Despite intense recent research, controlling the luminescence directivity remains a challenge for emitters with random positions and orientations, which is a key for several biomolecular screening applications. Here, we present full directional control of the fluorescence emission from molecules in water solution by an optical antenna made of a nanoaperture surrounded by a periodic set of shallow grooves in a gold film. For each emission wavelength, the fluorescence beam can be directed along a specific direction with a given angular width, hereby realizing a micrometer-size dispersive antenna. We demonstrate the fluorescence beaming results from an interference phenomenon and provide physical optics guidelines to control the fluorescence directivity by tuning the groove-nanoaperture distance. This photon-sorting capability provides a new approach for high-sensitivity screening of molecular species in solution.     

Les dechets de sables de fonderie en technique routiere

Every year a high quantity of foundry sand, adaptable to civil engineering, is produced by iron metallurgical industries. This waste was inventorized in France so as to know the output place and value their rate. Pollution hazard studies, performed in Germany and in France, have led to classify foundary sand as “banal” waste. The Laboratoire Régional des Ponts et Chaussées d'Autun has studied a definite case, the foundry sand cast up by Montbéliard Peugeot factories, laying emphasis on the stability under traffic of such a hydraulic binder treated material and their utilization for road construction. In a parallel direction with this study, a research has been carried out on blocking hazards of hydraulic-setting due to mineral or organic additives.     

Scratch and wear resistance of polyamide 6 reinforced with multiwall carbon nanotubes

While carbon nanotubes have been used for a variety of purposes, it was not known whether they can improve tribological properties of polymers. Polyamide 6 (PA6) has been reinforced with 0.2, 0.5 and 1.0 wt% of multiwall carbon nanotubes (MWCNTs) by melt mixing process and characterized by scanning electron microscopy (SEM), transmission electron microscopy, thermogravimetric analysis (TGA), scratching, sliding wear and tensile testing. TGA results for the air atmosphere show that MWCNTs shift the onset of thermal degradation to higher temperatures. Sliding wear tests show that the penetration depth decreases as the concentration of carbon nanotubes increases. However, the viscoelastic healing is hampered by the MWCNTs presence and the residual depths increase at the same time. Narrower scratch groove widths are seen in SEM for composites with MWCNTs, and scratch hardness increases. Tensile tests show an increase of 27% in the Young modulus value upon addition of 1.0% of MWCNTs. The stress at yield is also higher for the nanocomposites.     

Preparation of multinuclear microparticles using a polymerization in emulsion process

A new microencapsulation method, in which a paraffin medium and small sub‐micron spheres were encapsulated by an amino resin has been established. These multinuclear microparticles were made by polymerization in emulsion and characterized by scanning electron microscopy and interfacial tension measurements. This process is based on several emulsion mixings following Torza and Mason's approach, in which we combined the characteristics of a coacervation with a conventional interfacial reaction and an in situ polymerization followed by a water in oil in water emulsion. The inner phase of the microcapsules consisted of a mixture of paraffin and microspheres of poly(vinyl) alcohol/hydrated salt crosslinked by methylene diisocyanate. The encapsulation mechanism is based on the liquid/solid–liquid separation of methoxylolmelamines and will be described in this study to explain the surface morphology. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Carnobacterium maltaromaticum: Identification,isolation tools,ecology and technological aspects in dairy products

Carnobacterium species constitute a genus of Lactic Acid Bacteria (LAB) present in different ecological niches. The aim of this article is to summarize the knowledge about Carnobacterium maltaromaticum species at different microbiological levels such as taxonomy, isolation and identification, ecology, technological aspects and safety in dairy products. Works published during the last decade concerning C. maltaromaticum have shown that this non-starter LAB (NSLAB) could present major interests in dairy product technology. Four reasons can be mentioned: i) it can grow in milk during the ripening period with no competition with starter LAB, ii) this species synthesizes different flavouring compounds e.g., 3-methylbutanal, iii) it can inhibit the growth of foodborne pathogens as Listeria monocytogenes due to its ability to produce bacteriocins, iv) it has never been reported to be involved in human diseases as no cases of human infection have been directly linked to the consumption of dairy products containing this species.     

Protective effects of taurine on human hair follicle grown in vitro

Taurine is a naturally occurring beta-amino acid produced by methionine and cysteine metabolism. It is involved in a variety of physiological functions, including immunomodulatory and antifibrotic. Taking advantage of the ability of human hair follicle grown in vitro to recapitulate most of the characteristic features of normal hair follicle in vivo, we studied (i) taurine uptake by isolated human hair follicles; (ii) its effects on hair growth and survival rate; and (iii) its protective potential against transforming growth factor (TGF)-beta1, an inhibitor of in vitro hair growth and a master switch of fibrotic program. We showed that taurine was taken up by the connective tissue sheath, proximal outer root sheath and hair bulb, promoted hair survival in vitro and prevented TGF-beta1-induced deleterious effects on hair follicle.     

Part 3. General kinetic model of the sulfonation of PEEK fluoroarylketone chain‐end repeat unit

The sulfonation kinetics of the fluoroarylketone chain‐end repeat unit of PEEK was studied. To achieve this objective, the sulfonation reactions of a trimer, a tetramer and a polymer, each fluoroarylketone ended, were followed by ¹⁹F NMR. A general kinetic model was developed to determine the kinetic constants from ¹⁹F NMR data. The reliability of the kinetic model and of its mathematical expression was ensured. The kinetic constants are then calculated and discussed. In particular, they were compared with the dimer rate constants previously determined. Lastly and as a conclusion of this work, a general kinetic model describing the sulfonation of main chain repeat units of PEEK is proposed. © 2001 Society of Chemical Industry     

Numerical investigation of the impact of gas and cooling flow configurations on current and water distributions in a polymer membrane fuel cell through a pseudo-two-dimensional diphasic model

For optimal performances, proton exchange membrane fuel cells require fine water and thermal management. Accurate modelling of the physical phenomena occurring in the fuel cell is a key issue to improve fuel cell technology. Here, an analytic steady state diphasic 2D model of heat and mass transfer is presented. Through this model, the aim of this work is to study the influence of local events on the global performances of a fuel cell. A part of the complete model is a microscopic representation of the coupling between water transport and charge transfers in the electrodes. The thickness of the liquid layer around the reactive agglomerates is deduced from the saturation. The evolution of the quantity of water within the catalyst layer is monitored and its influence on the global performances of the cell is investigated. In gas diffusion layers (GDLs), liquid and vapour water transport through are computed regarding the temperature. The flow direction of cooling water modifies the current density distribution along the cell. The impact of the direction of air and hydrogen feeding channels are investigated. It can modify greatly the fuel cell mean current density and the net water transport coefficient. The counter-flow mode was preferable. Likewise, thanks to a better membrane hydration, it results in independent performances regarding the hydrogen inlet relative humidity or stoichiometry.