218 research outputs found

    Stock market series analysis using self-organizing maps

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    In this work a new clustering technique is implemented and tested. The proposed approach is based on the application of a SOM (self-organizing map) neural network and provides means to cluster U-MAT aggregated data. It relies on a flooding algorithm operating on the U-MAT and resorts to the Calinski and Harabask index to assess the depth of flooding, providing an adequate number of clusters. The method is tuned for the analysis of stock market series. Results obtained are promising although limited in scope.Neste trabalho é implementada e testada uma nova técnica de agrupamento. A abordagem proposta baseia-se na aplicação de uma rede neuronal SOM (mapa auto-organizado) e permite agrupar dados sobre a matriz de distancias (U-MAT). É utilizado um algoritmo de alagamento ("flooding") sobre a U-MAT e o índice de Calinski e Harabasz avalia a profundidade do alagamento determinando-se, assim, o número de grupos mais adequado. O método é desenhado especificamente para a análise de séries temporais da bolsa de valores. Os resultados obtidos são promissores, embora se registem ainda limitações

    New textile for personal protective equipment—plasma chitosan/silver nanoparticles nylon fabric

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    Fabric structures are prone to contamination with microorganisms, as their morphology and ability to retain moisture creates a proper environment for their growth. In this work, a novel, easily processed and cheap coating for a nylon fabric with antimicrobial characteristics was devel- oped. After plasma treatment, made to render the fabric surface more reactive sites, the fabric was impregnated with chitosan and silver nanoparticles by simply dipping it into a mixture of different concentrations of both components. Silver nanoparticles were previously synthesized using the Lee–Meisel method, and their successful obtention was proven by UV–Vis, showing the presence of the surface plasmon resonance band at 410 nm. Nanoparticles with 25 nm average diameter observed by STEM were stable, mainly in the presence of chitosan, which acted as a surfactant for silver nanoparticles, avoiding their aggregation. The impregnated fabric possessed bactericidal activ- ity higher for Gram-positive Staphylococcus aureus than for Gram-negative Pseudomonas aeruginosa bacteria for all combinations. The percentage of live S. aureus and P. aeruginosa CFU was reduced to less than 20% and 60%, respectively, when exposed to each of the coating combinations. The effect was more pronounced when both chitosan and silver were present in the coating, suggesting an effective synergy between these components. After a washing process, the antimicrobial effect was highly reduced, suggesting that the coating is unstable after washing, being almost completely removed from the fabric. Nevertheless, the new-coated fabric can be successfully used in single-use face masks. To our knowledge, the coating of nylon fabrics intended for face-mask material with both agents has never been reported.This study was supported by the Portuguese Foundation for Science and Technology (FCT), under the scope of the strategic funding of UIDB/04469/2020 unit, and BioTecNorte operation (NORTE-01-0145-FEDER-000004). funded by the European Regional Development, Fund under the scope of Norte2020—Programa Operacional Regional do Norte

    Proteolytic systems and AMP-activated protein kinase are critical targets of acute myeloid leukemia therapeutic approaches

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    The therapeutic strategies against acute myeloid leukemia (AML) have hardly been modified over four decades. Although resulting in a favorable outcome in young patients, older individuals, the most affected population, do not respond adequately to therapy. Intriguingly, the mechanisms responsible for AML cells chemoresistance/ susceptibility are still elusive. Mounting evidence has shed light on the relevance of proteolytic systems (autophagy and ubiquitin-proteasome system, UPS), as well as the AMPK pathway, in AML biology and treatment, but their exact role is still controversial. Herein, two AML cell lines (HL-60 and KG-1) were exposed to conventional chemotherapeutic agents (cytarabine and/or doxorubicin) to assess the relevance of autophagy and UPS on AML cells’ response to antileukemia drugs. Our results clearly showed that the antileukemia agents target both proteolytic systems and the AMPK pathway. Doxorubicin enhanced UPS activity while drugs’ combination blocked autophagy specifically on HL-60 cells. In contrast, KG-1 cells responded in a more subtle manner to the drugs tested consistent with the higher UPS activity of these cells. In addition, the data demonstrates that autophagy may play a protective role depending on AML subtype. Specific modulators of autophagy and UPS are, therefore, promising targets for combining with standard therapeutic interventions in some AML subtypes.We would like to acknowledge Dr. Agostinho Carvalho and Dr. Manuel Guerreiro (Hospital da Arrabida, Vila Nova de Gaia, Portugal) for the critical review and discussion of the manuscript and for the work support. This work was supported by FCT - Fundacao para a Ciencia e Tecnologia (PTDC/BIA-MIC/114116/2009). A.F., O.P. and B.S.M. have fellowships from FCT (SFRH/BD/51991/2012, SFRH/BD/52292/2013, and SFRH/BPD/90533/2012, respectively). M.M.A. was supported by CCDR-N (QREN) in the scope of the project "Integration of cutting-edge health science research and ground-breaking technologies for the development of new clinically useful therapies, tissue regeneration strategies, advanced prophylactic measures and diagnosis methods - (N-01-01-01-24-01-07) - RL5" (UMINHO/BI/245/2013)

    Lessons Learned – EduPARK

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    Resumo indisponível.publishe

    Web-based forest resources management decision support system

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    In this paper, we present a web-based decision support system (DSS)—wSADfLOR—to facilitate the access of stakeholders to tools that may contribute to enhancing forest management planning. The emphasis is on a web-based architecture and a web graphic user interface (wGUI) that may effectively support the analysis of trade-offs between ecosystem services in order to address participatory and sustainable forest management objectives. For that purpose, the wGUI provides remote access to a management information system, enabling users to analyze environmental and biometric data and topological information as well. Moreover, the wGUI provides remote access to forest simulators so that users may define and simulate prescriptions such as chronological sequences of management options and the corresponding forest ecosystem services outcomes. Remote access to management planning methods is further provided so that users may input their objectives and constraints. The wGUI delivers information about tradeoffs between ecosystem services in the form of decision maps so that users in different locations may negotiate bundles of ecosystem services as well as the plan needed to provide them. The multiple criteria programming routines provide proposals for management plans that may be assessed further, using geographical and alphanumeric information provided by the wGUI. Results for an application to a forested landscape extending to 14,388 ha are presented and discussed. This landscape provides several ecosystem services and the development of its management plan involves multiple stakeholders. Results show that the web-based architecture and the wGUI provide effective access for stakeholders to information about the forest management planning area and to decision support tools that may contribute to addressing complex multi-objective and multiple-decision-maker management planning contexts. They also highlight that the involvement and participation of stakeholders in the design of the web-based architecture contributes to assuring the quality and the usability of the systeminfo:eu-repo/semantics/publishedVersio

    Chondrosia reniformis marine-sponge collagen membranes for skin re-epithelialization

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    Chondrosia reniformis collagen has been identified as mainly of type IV. Being collagen IV the main component of the epidermal basal layer [1], C. reniformis represents a valuable source to be explored in the skin regeneration field. This work envisaged the production of C. reniformis collagen membranes for the selection of rapidly adherent epidermal cells, like the commercial collagen coatings, and for their subsequent culture. This approach would permit a single system for culturing and carrying basal epidermal cells aimed at re-epithelialize skin wounds. Materials and Methods The collagen of C. reniformis marine-sponge was extracted with 100mM Tris-HCl, 10mM EDTA, 8M urea and 100mM 2-mercaptoethanol. To define the best re-solubilization conditions, the obtained precipitate was dissolved in five different solutions: Solution A: 100mM Tris-HCl+8M Urea+10mM EDTA (pH 9.5); Solution B: 50mM Tris-HCl+1M NaCl (pH 7.4); Solution C: 100mM Tris-HCl (pH 7.4); Solution D: 0.5% H2O2 (v/v) (pH 11) and Solution E: 100mM Tris-HCl (pH 9.5). Solutions of 1% collagen were prepared and cross-linking was performed with HMDI, genipin and EDC/NHS at different concentrations. The membranes were obtained by solvent-casting and/or freeze-drying, and their stability was tested both in PBS and culture medium, for at least 7 days. Morphological characterization of the membranes was carried out by scanning electron microscopy (SEM). Cytotoxicity, based on metabolic activity (MTS assay) and cell proliferation (DNA quantification) analysis of the 100mM Tris-HCl (pH 9.5) and 8mM EDC/NHS cross-linked collagen membranes, was assessed with L929 cells. Results were analyzed by IBM SPSS Statistics Version 20 using one-way ANOVA and Kruskall-Wallis test. Significance was set for

    Editorial do n.º normal de dezembro da Revista Online Indagatio Didactica

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    Após processo de revisão por pares duplamente cega, os cinco artigos aceites, inscrevem-se nas secções ‘Desenvolvimento Curricular e Didática’ e ‘Políticas e Avaliação em Educação’. Os três artigos afetos à secção ‘Desenvolvimento Curricular e Didática’ respeitam à formação de professores, nos contextos de São Tomé e Príncipe, Brasil e Portugal. A diversidade ainda se estende às áreas disciplinares visadas. À secção ‘Políticas e Avaliação em educação’ afetaram-se dois artigos.

    Stability and enzymatic studies with omeprazole: hydroxypropyl-β-cyclodextrin

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    The original publication is available at www.springerlink.com. A publicação original está disponível em www.springerlink.comOmeprazole (OME) exhibits low stability to light, heat and humidity. In stress conditions OME stability should improve under inclusion complex form with hydroxypropyl-b-cyclodextrin (HPbCD). Stability of OME, its physical mixture (PM) with HPbCD and OME:HPbCD inclusion complex was assessed during 60 days. The inclusion complexes were prepared by kneading and freezedrying techniques and characterized by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). A molecular modelling was also held to predict the most probable tridimensional conformation of inclusion complex OME:HPbCD. The inhibitory activity of free and complexed OME on selected enzymes, namely, papain (protease model of the proton pump) and acetylcholinesterase (enzyme present in cholinergic neurons and also involved in Alzheimer’s disease) was compared. The results obtained show that HPbCD do not protect against OME degradation, in any prepared powder, in the presence of light, heat and humidity. This may indicate that the reactive group of OME is not included in the HPbCD cavity. This fact is supported by molecular modelling data, which demonstrated that 2-pyridylmethyl group of OME is not included into the cyclodextrin cavity. In relation to enzymatic assays it was observed that free OME and OME in the binary systems showed identical inhibitory activity on papain and acethylcolinesterase, concluding that HPbCD do not affect OME activity on these two enzymes

    Targeting liver stage malaria with metformin

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    Copyright: © 2019, American Society for Clinical InvestigationDespite an unprecedented 2 decades of success, the combat against malaria - the mosquito-transmitted disease caused by Plasmodium parasites - is no longer progressing. Efforts toward eradication are threatened by the lack of an effective vaccine and a rise in antiparasite drug resistance. Alternative approaches are urgently needed. Repurposing of available, approved drugs with distinct modes of action are being considered as viable and immediate adjuncts to standard antimicrobial treatment. Such strategies may be well suited to the obligatory and clinically silent first phase of Plasmodium infection, where massive parasite replication occurs within hepatocytes in the liver. Here, we report that the widely used antidiabetic drug, metformin, impairs parasite liver stage development of both rodent-infecting Plasmodium berghei and human-infecting P. falciparum parasites. Prophylactic treatment with metformin curtails parasite intracellular growth in vitro. An additional effect was observed in mice with a decrease in the numbers of infected hepatocytes. Moreover, metformin provided in combination with conventional liver- or blood-acting antimalarial drugs further reduced the total burden of P. berghei infection and substantially lessened disease severity in mice. Together, our findings indicate that repurposing of metformin in a prophylactic regimen could be considered for malaria chemoprevention.This work was supported by Fundação para a Ciência e Tecnologia (Portugal) PTDC/SAU-MET/118199/2010 to LMS and European Research Council Proof of Concept Grant to MMM (ERC-2015-PoC-DL3–713691-REUSE4MALARIA).info:eu-repo/semantics/publishedVersio
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