590 research outputs found

    Nanosieves Fabricated By Interference Lithography And Electroforming

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    Self-sustaining Nickel membranes with periodic and regular distribution of pores, in the scale of hundred of nanometers, were produced by interference lithography and electroplating. The process consists in the recording of submicrometric 2D periodic photoresist columns, on a metal-coated glass substrate, using the double exposure of an interference fringe pattern. As the photoresist is a good electrical isolator, when the sample is immersed in a Ni electroplating bath, the array of photoresist columns impedes the Nickel deposition in the patterned areas. A nickel film is then growth among the photoresist columns with a thickness up to 80 % of the height of the columns. In order to release the submicrometric membrane from the substrate, a thick hexagonal Nickel sustaining structure is electroformed, using conventional photolithography. The dimensions of the sustaining structure can be adapted in order to fulfill the pressure requirements of the filtration system. The good uniformity of the pore sizes as well as the smooth of the surface make such devices very interesting for separation of particles by size in filtration systems.6037Sard Ghayeni, S.B., Beatson, P.J., Fane, A.J., Schneider, R.P., Bacterial passage through microfiltration membranes in wastewater applications (1999) J. Membr. Sci., 153, pp. 71-82(2002) Life Science CatalogueCalvo, J.I., Hernandez, A., Pradanos, P., Martinez, L., Bowen, W.R., Pore size distribution in microporous membranes, II bulk characterization of track-etched filters by air porometry and mercury prosimetry (1995) Journal of Colloid and Interface Science, 176, pp. 467-478Han, K., Xu, W., Ruiz, A., Ruchhoeft, P., Chellam, S., Fabrication and characterization of polymeric microfiltration membranes using aperture array lithography (2005) J. Membr. Sci., 249, pp. 193-206Kuiper, S., Van Wolferen, H., Van Rijn, C., Nijdam, W., Krijnem, G., Elwenspoek, M., Fabrication of microsieves with sub-micron pore size by laser interference lithography (2001) Journal, of Micromehcanics and Microengineering, 11, pp. 33-37Van Rijn, C.J.M., Veldhuis, G.J., Kuiper, S., Nanosieves with microsystem tecnology for microfiltration applications (1998) Nanotechnology, 9, pp. 343-345Kuiper, S., Boer, M.D., Van Rijn, C., Nijdarh, W., Krijnen, G., Elwenspoek, M., Wet and dry etching techniques for the release of sub-micrometre perforated membranes (2000) Journal of Micromechanics and Microengineering, 10, pp. 171-174Gutierrez-Rivera, L.E., De Carvalho, E.J., Suva, M.A., Cescato, L., Metallic submicrometric sieves fabricated by interferometric litography and electroforming (2005) Journal of Micromechanics and Microengineering, 15, pp. 1932-1937Griffiths, S.K., Nilson, R.H., Hruby, J.M., (1996) Modeling Electrodeposition for LIGA Microdevice Fabrication, , http://www.ca.sandia.gov/liga/process_archives.html, Sandia National Laboratories, Livermore, CaliforniaFrejlich, J., Cescato, L., Mendes, G.F., Analysis of an active stabilization system for an holographic setup (1998) Appl. Opt., 27, pp. 1967-1976Zaidi, H.S., Brueck, S.R.J., Multiple-exposure interferometric lithography (1993) J. Vac. Sci. Technol. B, 11, pp. 658-666Mello, B.A., Costa, I.F., Lima, C.R.A., Cescato, L., Developed profile of holographically exposed photoresist gratings (1995) Applied Optics, 34, pp. 597-603Mack, C.A., Development of positive photoresists (1987) J. Electrochem. Soc., 134, pp. 148-152Spiro, P., (1971) Electroforming: A Comprehensive Survey of Theory, Practice and Commercial Applications2th Edition, , Robert Draper LTDKuiper, S., Van Rijn, C.J., Nijdam, W., Elwenspoek, M.C., Development and applications of very high flux microfiltration membranes (1998) Journal of Membrane Science, 150, pp. 1-8www.mediacy.co

    Feeding strategies and energy to protein ratio on tambaqui performance and physiology

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    The objective of this work was to evaluate the effect of feed deprivation and refeeding with diets containing different energy to protein ratios (E/P) on the performance and physiology of juvenile tambaqui (Colossoma macropomum). A 4x2 factorial arrangement with three replicates was used, with four E/P ratios (11.5, 10.5, 9.5, and 8.5 kcal g-1 digestible energy per protein) and two feeding regimens (with and without deprivation), during 60 days. Fish from the food-deprived group were fasted for 14 days and refed from the fifteenth to the sixtieth day, whereas the remaining fish were fed for 60 days. At the end of the experimental period, weight of fish subjected to food deprivation was lower than that of those continuously fed; however, this condition did not influence the physiological parameters analyzed. Tambaqui fed 11.5 kcal g-1 achieved lower final weight than those fed with the other diets, in both regimens. Among the physiological parameters, only plasma protein presented significant increase in fish fed 8.5 kcal g-1, in both feeding regimens, probably due to the higher dietary protein concentration. These results indicate that fish show a partial compensatory growth, and that 10.5 kcal g-1 can be recommended for the diet of juvenile tambaqui

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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