203 research outputs found

    Magneto-optical investigation of the field-induced spin-glass insulator to ferromagnetic metallic transition of the bilayer manganite (La0.4_{0.4}Pr0.6_{0.6})1.2_{1.2}Sr1.8_{1.8}Mn2_2O7_7

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    We measured the magneto-optical response of (La0.4_{0.4}Pr0.6_{0.6})1.2_{1.2}Sr1.8_{1.8}Mn2_2O7_7 in order to investigate the microscopic aspects of the magnetic field driven spin-glass insulator to ferromagnetic metal transition. Application of a magnetic field recovers the ferromagnetic state with an overall redshift of the electronic structure, growth of the bound carrier localization associated with ferromagnetic domains, development of a pseudogap, and softening of the Mn-O stretching and bending modes that indicate a structural change. We discuss field- and temperature-induced trends within the framework of the Tomioka-Tokura global electronic phase diagram picture and suggest that controlled disorder near a phase boundary can be used to tune the magnetodielectric response. Remnants of the spin-glass insulator to ferromagnetic metallic transition can also drive 300 K color changes in (La0.4_{0.4}Pr0.6_{0.6})1.2_{1.2}Sr1.8_{1.8}Mn2_2O7_7.Comment: 9 pages, 8 figure

    Binder effectiveness of microcapsules applied onto cotton fabrics during laundry

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    [EN] Microcapsules can be added to fabric in industrial processes; however, they have not been widely spread among industrial companies. In this study, we suggest the possibility of reloading microcapsules onto a fabric while clothes are washed. The effectiveness of different resins when microcapsules are applied in washing machine during domestic laundry process has been studied. Microcapsules containing lavender fragrance and melamine formaldehyde shell were adhered to the fabric by means of one acrylic acid as a resin (RES) or some cross-linking agents, such as butanetetracarboxylic acid or succinic acid (SUC). In order to evaluate their behaviour, some laundering or ironing tests were conducted according to international standards (ISO). Every sample from the laboratory was studied with scanning electron microscopy and with a particle size counter. As a result, we could observe which was the most suitable auxiliary used to bind microcapsules to fabric, and conclude that the conditions in which we obtained the application with SUC as binder and cured at 150 °C for 2 min show the optimal results. It was demonstrated that domestic laundry is a suitable process to incorporate microcapsules to garments.Authors gratefully acknowledge the financial support received by this research project from the Spanish government in the programme 'Plan Nacional 2008-2011' reference Mat 2009-14210-C02-01.Bonet Aracil, MA.; Bou Belda, E.; Monllor Pérez, P.; Gisbert; Jaime (2016). Binder effectiveness of microcapsules applied onto cotton fabrics during laundry. The Journal of the Textile Institute. 107(3):300-306. https://doi.org/10.1080/00405000.2015.1029808S300306107

    Effect of plasma surface modification on the biocompatibility of UHMWPE

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    In this paper active screen plasma nitriding (ASPN) is used to chemically modify the surface of UHMWPE. This is an unexplored and new area of research. ASPN allows the homogeneous treatment of any shape or surface at low temperature; therefore, it was thought that ASPN would be an effective technique to modify organic polymer surfaces. ASPN experiments were carried out at 120 °C using a dc plasma nitriding unit with a 25% N2 and 75% H2 atmosphere at 2.5 mbar of pressure. UHMWPE samples treated for different time periods were characterized by nanoindentation, FTIR, XPS, interferometry and SEM. A 3T3 fibroblast cell line was used for in vitro cell culture experiments. Nanoindentation of UHMWPE showed that hardness and elastic modulus increased with ASPN treatment compared to the untreated material. FTIR spectra did not show significant differences between the untreated and treated samples; however, some changes were observed at 30 min of treatment in the range of 1500–1700 cm−1 associated mainly with the presence of N−H groups. XPS studies showed that nitrogen was present on the surface and its amount increased with treatment time. Interferometry showed that no significant changes were observed on the surfaces after the treatment. Finally, cell culture experiments and SEM showed that fibroblasts attached and proliferated to a greater extent on the plasma-treated surfaces leading to the conclusion that ASPN surface treatment can potentially significantly improve the biocompatibility behaviour of polymeric materials

    Admixture in the Hispanics of the San Luis Valley, Colorado, and its implications for complex trait gene mapping

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    Hispanic populations are a valuable resource that can and should facilitate the identification of complex trait genes by means of admixture mapping (AM). In this paper we focus on a particular Hispanic population living in the San Luis Valley (SLV) in Southern Colorado.We used a set of 22 Ancestry Informative Markers (AIMs) to describe the admixture process and dynamics in this population. AIMs are defined as genetic markers that exhibit allele frequency differences between parental populations ≥30%, and are more informative for studying admixed populations than random markers. The ancestral proportions of the SLV Hispanic population are estimated as 62.7 ± 2.1% European, 34.1 ± 1.9% Native American and 3.2 ± 1.5% West African. We also estimated the ancestral proportions of individuals using these AIMs. Population structure was demonstrated by the excess association of unlinked markers, the correlation between estimates of admixture based on unlinked marker sets, and by a highly significant correlation between individual Native American ancestry and skin pigmentation (R 2 = 0.082, p < 0.001). We discuss the implications of these findings in disease gene mapping efforts.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65937/1/j.1529-8817.2003.00084.x.pd

    A Program for At-Risk High School Students Informed by Evolutionary Science

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    Improving the academic performance of at-risk high school students has proven difficult, often calling for an extended day, extended school year, and other expensive measures. Here we report the results of a program for at-risk 9th and 10th graders in Binghamton, New York, called the Regents Academy that takes place during the normal school day and year. The design of the program is informed by the evolutionary dynamics of cooperation and learning, in general and for our species as a unique product of biocultural evolution. Not only did the Regents Academy students outperform their comparison group in a randomized control design, but they performed on a par with the average high school student in Binghamton on state-mandated exams. All students can benefit from the social environment provided for at-risk students at the Regents Academy, which is within the reach of most public school districts
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