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In the study of environmental DNA (eDNA), the rate of water filtration and the amount of DNA obtained are of general interest to researchers. We compared the PCTE filters with different pore sizes in enriching total DNA and fish eDNA from water samples. We also designed and tested a new filter device with a PET pad (5 µm) superimposed on a PCTE membrane (3 µm) and compared it to a pure PCTE filter. A comprehensive evaluation of filtration time, eDNA concentration, fish DNA quantification, and fish species detected showed that the shortest average filtration time was obtained with the 8 µm pore size (2 min 9 s) and the longest average filtration time was obtained with the 0.2 µmpore size (32 min 6 s). The highest average DNA concentration was 3.785 ng/µL for the 0.2 µmfilter and the lowest was 0.577 ng/µL for the 8 µm filter; meanwhile, the concentrations of fish DNA measured by quantitative PCR were 5.02E+02(8 µm), 4.79E+02(3 µm), 1.63E+03(1.2 µm), 5.95E+03(0.2 µm) copies of fish DNA per µl and there was no significant difference in the results between them (p > 0.05). The sequencing results showed that 17 fish species were detected in the 0.2 µm filter, 10 species in the 1.2 µm filter, 12 species in the 3 µm filter and 11 species in the 8 µm filter. Comparing to 3 µm and 0.2 um, the average filtration time in stacked-filter was reduced by 4 and 24 min, respectively, while the average concentration was 2.46 and 1.55 times higher than the former. The qPCR results showed that the number of eDNA copies of the samples enriched with the 3 µm and stacked-filter was 4.79E+02 and 1.53E+04, respectively. 3 µm and stacked-filter showed significant differences (p < 0.05), while 0.2 µm and stacked-filter did not show significant differences (p > 0.05). Sixteen fish species were detected by the stacked-filter. The number of eDNA obtained and the number of fish species detected were higher than those of the pure PCTE filter, while clogging during filtration was effectively avoided. We recommend using the stacked-filter to enrich eDNA from water samples. [ABSTRACT FROM AUTHOR]

Composite membranes based on porous support membranes filled with a proton-conducting polymer appear to be a promising approach to develop novel proton exchange membranes (PEMs). It allows optimization of the properties of the filler and the matrix separately, e.g. for maximal conductivity of the former and maximal physical strength of the latter. In addition, the confinement itself can alter the properties of the filling ionomer, e.g. toward higher conductivity and selectivity due to alignment and restricted swelling. This article reviews the literature on PEMs prepared by filling of submicron and nanometric size pores with Nafion and other proton-conductive polymers. PEMs based on alternating perfluorinated and non-perfluorinated polymer systems and incorporation of fillers are briefly discussed too, as they share some structure/transport relationships with the pore-filling PEMs. We also review here the background knowledge on structural and transport properties of Nafion and proton-conducting polymers in general, as well as experimental methods concerned with preparation and characterization of pore-filling membranes. Such information will be useful for preparing next-generation composite membranes, which will allow maximal utilization of beneficial characteristics of polymeric proton conductors and understanding the complicated structure/transport relationships in the pore-filling composite PEMs. [ABSTRACT FROM AUTHOR]

The high proton conductivity of Nafion© membranes in direct methanol fuel cells is attributed to a random three dimensional 3D network of elongated ion channels formed by bundles of rod-like inverted micelles. However, this network is also responsible for high methanol crossover. In addition, its conductivity is impaired at temperatures 120 °C and above due to ion channel rearrangement, thus limiting the operational temperature to 60-80 °C. Here we report a composite proton exchange membrane prepared by filling the pores of polycarbonate track-etched membrane with Nafion, which promote channel orientation roughly normal to the surface. The proton conductivity of this geometry is significantly enhanced, presumably due to the restricted swelling, resulting in a better ion channel connectivity and realignment in the axial pore direction upon hydration. The permeability of sodium chloride and methanol, though, is suppressed, presumably due to formation of regions of closely packed sulfonic groups, which facilitate proton transfer but strongly exclude other solutes. Composite membranes with improved conductivity and selectivity based on the principle presented here are expected to allow operating direct methanol fuel cells at higher temperatures and with higher methanol concentrations, thus reducing costs and increasing the efficiency. [ABSTRACT FROM AUTHOR]

Due to enormous pressure from national and international marketplaces, computer integrated manufacturing ( cim) has become a tremendously important area for both research and development. However, the current state of the art is still characterized by islands of automation. In order to connect these islands, appropriate frameworks have to be developed to integrate heterogeneous computer aided design ( cad) tools. We present in this paper a federated approach to tool integration in distributed and heterogeneous environments making tools evolve in an autonomous way. We have experimented this approach by integrating propel and spex cad tools in the dmms ( design management and manufacturing system) environment backed by a common pcte providing an open repository for software development. We use in our experiment an implementation of pcte 1.5 named Emeraude V12.5, product of gie emeraude repository. [ABSTRACT FROM AUTHOR]