1,085 research outputs found

    Environmental risk assessment in a contaminated estuary: an integrated weight of evidence approach as a decision support tool

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    Environmental risk assessment of complex ecosystems such as estuaries is a challenge, where innovative and integrated approaches are needed. The present work aimed at developing an innovative integrative methodology to evaluate in an impacted estuary (the Sado, in Portugal, was taken as case study), the adverse effects onto both ecosystem and human health. For the purpose, new standardized lines of evidence based on multiple quantitative data were integrated into a weight of evidence according to a best expert judgment approach. The best professional judgment for a weight of evidence approach in the present study was based on the following lines of evidence: i) human contamination pathways; ii) human health effects: chronic disease; iii) human health effects: reproductive health; iv) human health effects: health care; v) human exposure through consumption of local agriculture produce; vi) exposure to contaminated of water wells and agriculture soils; vii) contamination of the estuarine sedimentary environment (metal and organic contaminants); viii) effects on benthic organisms with commercial value; and ix) genotoxic potential of sediments. Each line of evidence was then ordinally ranked by levels of ecological or human health risk, according to a tabular decision matrix and expert judgment. Fifteen experts scored two fishing areas of the Sado estuary and a control estuarine area, in a scale of increasing environmental risk and management actions to be taken. The integrated assessment allowed concluding that the estuary should not be regarded as impacted by a specific toxicant, such as metals and organic compounds hitherto measured, but by the cumulative risk of a complex mixture of contaminants. The proven adverse effects on species with commercial value may be used to witness the environmental quality of the estuarine ecosystem. This method argues in favor of expert judgment and qualitative assessment as a decision support tool to the integrative management of estuaries. Namely it allows communicating environmental risk and proposing mitigation measures to local authorities and population under a holistic perspective as an alternative to narrow single line of evidence approaches, which is mandatory to understand cause and effect relationships in complex areas like estuaries.info:eu-repo/semantics/publishedVersio

    The pulsating DA white dwarf star EC 14012-1446: results from four epochs of time-resolved photometry

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    The pulsating DA white dwarfs are the coolest degenerate stars that undergo self-driven oscillations. Understanding their interior structure will help to understand the previous evolution of the star. To this end, we report the analysis of more than 200 h of time-resolved CCD photometry of the pulsating DA white dwarf star EC 14012-1446 acquired during four observing epochs in three different years, including a coordinated three-site campaign. A total of 19 independent frequencies in the star's light variations together with 148 combination signals up to fifth order could be detected. We are unable to obtain the period spacing of the normal modes and therefore a mass estimate of the star, but we infer a fairly short rotation period of 0.61 +/- 0.03 d, assuming the rotationally split modes are l=1. The pulsation modes of the star undergo amplitude and frequency variations, in the sense that modes with higher radial overtone show more pronounced variability and that amplitude changes are always accompanied by frequency variations. Most of the second-order combination frequencies detected have amplitudes that are a function of their parent mode amplitudes, but we found a few cases of possible resonantly excited modes. We point out the complications in the analysis and interpretation of data sets of pulsating white dwarfs that are affected by combination frequencies of the form f_A+f_B-f_C intruding into the frequency range of the independent modes.Comment: 14 pages, 6 figures, 6 tables. MNRAS, in pres

    Development of novel magnetoliposomes containing nickel ferrite nanoparticles covered with gold for applications in thermotherapy

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    Multifunctional nanosystems combining magnetic and plasmonic properties are a promising approach for cancer therapy, allowing magnetic guidance and a local temperature increase. This capability can provide a triggered drug release and synergistic cytotoxic effect in cancer cells. In this work, nickel ferrite/gold nanoparticles were developed, including nickel ferrite magnetic nanoparticles decorated with plasmonic gold nanoparticles and core/shell nanostructures (with a nickel ferrite core and a gold shell). These nanoparticles were covered with a surfactant/lipid bilayer, originating liposome-like structures with diameters below 160 nm. The heating capacity of these systems, upon excitation with light above 600 nm wavelength, was assessed through the emission quenching of rhodamine B located in the lipid layer. The developed nanosystems show promising results for future applications in thermotherapy.This research was funded by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UID/FIS/04650/2019) and through the research project PTDC/QUI-QFI/28020/2017 (POCI-01-0145-FEDER-028020), financed by European Fund of Regional Development (FEDER), COMPETE2020, and Portugal2020. The magnetic measurements were supported by projects UTAP-EXPL/NTec/0046/2017, NORTE-01-0145-FEDER-028538, and PTDC/FIS-MAC/29454/2017. I.S.R.R. acknowledges FCT for a research grant under CF-UM-UP Strategic Funding (UID/FIS/04650/2019)

    Magnetogels based on iron oxide nanoparticles and peptide hydrogels containing Naproxen and/or RGD

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    In this work, iron oxide nanoparticles, with diameters around 12 nm, were synthesized by coprecipitation method in aqueous solution. These nanoparticles exhibit a superparamagnetic behavior, with a coercive field of 9.7 Oe and a blocking temperature of 118 K. The nanoparticles were successfully incorporated in peptide-based hydrogels containing naproxen (Npx) and/or RGD. The ability of these magnetogels to act as drug nanocarriers is being investigated, aiming at developing multifunctional therapeutic nanosystems.info:eu-repo/semantics/publishedVersio

    Magnetic liposomes containing calcium ferrite nanoparticles for breast cancer therapy

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    In this work, calcium ferrite nanoparticles were prepared and characterized. The structural and magnetic properties of the nanoparticles were evaluated by XRD, TEM and SQUID. The synthesized nanoparticles were either entrapped in liposomes, originating aqueous magnetoliposomes (AMLs), or covered with a lipid bilayer, forming solid magnetoliposomes (SMLs). Magnetoliposomes present average diameters around 150 nm, suitable for biomedical applications. The magnetoliposomes were loaded with new potential anticancer drugs, thienopyridine derivatives, with a strong antitumor activity against breast cancer cells.This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UID/FIS/04650/2013) and of CQUM (UID/QUI/00686/2013). FCT, POPH-QREN and FSE are acknowledged for the PhD grants of A. R. O. Rodrigues (SFRH/BD/90949/2012) and V. A. Machado (SFRH/BD/77373/2011) and for financial support to MAP-Fis Joint Doctoral Programme.info:eu-repo/semantics/publishedVersio

    O projecto nacional de educação pelos pares da Fundação Portuguesa “A comunidade contra a sida” em escolas EB2/3 do Porto

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    O Projecto Nacional de Educação pelos Pares, focado na sexualidade e prevenção do VIH/ SIDA, foi criado pela Fundação Portuguesa “A Comunidade Contra a SIDA” no âmbito do Centro de Aconselhamento e Orientação de Jovens (CAOJ). O processo de aprendizagem, desenvolvido a partir do diagnóstico das necessidades de formação do público-alvo, recorre a metodologias activas que visam educar os adolescentes para uma vivência gratificante da sua sexualidade e prepará-los para assumirem o seu papel de “pares educadores” de colegas mais jovens. Esta educação de pares dirigida a alunos que frequentam o 3º ciclo do Ensino Básico é dinamizada, numa primeira fase, por jovens voluntários universitários organizados em Brigadas Universitárias de Intervenção (BUI) e no Teatro Universitário de Intervenção (TUI). Estes voluntários, com o acompanhamento de professores destacados para o CAOJ, responsáveis pela sua formação pedagógica, desenvolvem o projecto com alunos do 7º ao 9º ano de escolaridade. No terceiro ano de formação, os alunos do 3º ciclo organizados em Brigadas Escolares de Intervenção (BEI) iniciam a sua acção como educadores dos colegas mais novos, geralmente dos 2º e 1º ciclos. Esta comunicação, pretende mostrar a dinâmica deste Projecto desenvolvido em cinco escolas EB2/3 do Porto e discutir, com base em evidências recolhidas junto dos professores, voluntários e alunos envolvidos, alguns resultados obtidos neste ano lectivo
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