40 research outputs found

    RENEB intercomparisons applying the conventional Dicentric Chromosome Assay (DCA)

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    Purpose: Two quality controlled inter-laboratory exercises were organized within the EU project ‘Realizing the European Network of Biodosimetry (RENEB)’ to further optimize the dicentric chromosome assay (DCA) and to identify needs for training and harmonization activities within the RENEB network. Materials and methods: The general study design included blood shipment, sample processing, analysis of chromosome aberrations and radiation dose assessment. After manual scoring of dicentric chromosomes in different cell numbers dose estimations and corresponding 95% confidence intervals were submitted by the participants. Results: The shipment of blood samples to the partners in the European Community (EU) were performed successfully. Outside the EU unacceptable delays occurred. The results of the dose estimation demonstrate a very successful classification of the blood samples in medically relevant groups. In comparison to the 1st exercise the 2nd intercomparison showed an improvement in the accuracy of dose estimations especially for the high dose point. Conclusions: In case of a large-scale radiological incident, the pooling of ressources by networks can enhance the rapid classification of individuals in medically relevant treatment groups based on the DCA. The performance of the RENEB network as a whole has clearly benefited from harmonization processes and specific training activities for the network partners

    Micelle-smectic phase coexistence: Origin of the maximum swelling of a mixed lamellar phase

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    We use the water corner of the model ternary system water/DDAB (a cationic double tailed surfactant)/LS (an uncharged single chain glycolipid) to investigate maximum swelling of a charged lamellar phase. The phase diagram is determined by visual observation and small angle neutron scattering. Upon the addition of the glycolipid in this mixed lamellar structure, a decrease of the maximum swelling is observed. A transition from vesicles to micelles is also evidenced in the dilute coexisting phase. By calculating explicitly the osmotic pressure in the micellar phase and in the lamellar phase through the Poisson-Boltzmann equation, we demonstrate that equilibrium of the osmotic pressure in the two phases and depletion of the lamellar phase by the micellar phase explain quantitatively the decrease of maximum swelling observed when the LS to DDAB ratio increases

    Two-Phase Electrolysis Modelling : Two Scales Numerical and Experimental Investigation

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    218th ECS Meeting - Las Vegas, Nevada, USA - October 10-15 201

    Multi-Ion Deposition Modelling: Copper and Zinc Layers Production Application

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    218th ECS Meeting - Las Vegas, Nevada, USA - October 10-15 201

    Multi-Ion Deposition Modelling: Copper and Zinc Layers Production Application

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    218th ECS Meeting - Las Vegas, Nevada, USA - October 10-15 201

    New carbon nanotubes growth process in a closed microfabricated channel for liquid chromatography application

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    International audienceThe present paper describes a new process for the production of chromatographic columns made out of silicon, containing a micropillar array nanostructured with carbon nanotubes, and suitable for use in the reversed phase mode. According to this original collective process, a nickel layer sputtered on the whole wafer is used at the same time to realize the bonding process of the silicon cap cover, as well as to catalyze the carbon nanotubes growth on the sidewalls of the micropillars in the closed microsystem. The development of the bonding process via the formation of nickel silicide and the optimization of the growth of a homogenous layer of carbon nanotubes along the channel length are described. Preliminary chromatographic experiments with a mixture of two amines demonstrate the possibility to implement, in the hydrodynamic pumping mode, reproducible and efficient chromatographic separations with such a carbon nanotubes based stationary phase

    Development of a new phase for lab-on-a-chip extraction of polycyclic aromatic hydrocarbons from water

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    International audienceThis work reports on the improved performance using nanoporous organosilicate (SiOCH) for lab-on a-chip extraction of organic pollutants from natural waters. Validations were carried out for polycyclic aromatic hydrocarbons (PAHs) extraction, and the results were compared with the commonly used SBSE laboratory technique (Stir-Bar Sorptive Extraction). While a previous study performed with PDMS coated lab-on-a-chips had showed limitations for the most polar PAHs (log K-ow < 5.5) and real matrices, we demonstrate here that, thanks to the novel phase, there is a good affinity for PAHs, even in natural waters. An improved microfluidic device in term of channel width and chip total area could be selected. Most importantly, the extraction time of 20 min still used with this type of microfluidic device is very short compared to the 24 h needed with the SBSE laboratory technique. Moreover, the high specific surface area of the nanoporous phase reduces the matrix effects related to interferences with dissolved organic matter. Therefore these new porous SiOCH coated extraction microchips appear as a good alternative to PDMS-based extraction techniques such as SBSE and should be used for further development of field analysis devices
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