639 research outputs found

    Can Latin America Move Forward after a Lost Decade in Technical Change? …Looking at Opportunities for Knowledge-based Change in Times of Increasing Uncertainty

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    In view of the current global context, which challenges are facing science- and technology-based developments and cooperation in a way to contribute for policies that stimulate localized learning, innovation and endogenous development in Latin America? This broad question has motivated the work behind the Special Issue introduced by this paper, which considers the development of case studies in selected Latin America regions. The analysis lead us to argue that value-based networks have the potential to make both public policies and markets more effective, promoting learning trajectories for the inclusive development of regions. But they require effective public investments to keep attracting and qualifying human resources, together with long-term developments towards technical industries and export capacity for emerging markets worldwide. Our analysis argues about the unique potential for further developing Latin America through strategic international, knowledge-based ventures, exploring the emerging role the internationalization of universities and scientific institutions may play at a global level. Above all, they require the systematic observation of science and technical change in international comparison, as well as a relational infrastructure for collective action, at an international level, in a context much influenced by a dynamic of change and a necessary balance between the creation and diffusion of knowledge towards the endogenous development of all parts involved. The role of Latin America Universities and science policies based on international cooperation are considered to be particularly important in this process.published_or_final_versio

    DNA vaccines against dengue virus based on the ns1 gene: The influence of different signal sequences on the protein expression and its correlation to the immune response elicited in mice

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    AbstractWe analyzed four DNA vaccines based on DENV-2 NS1: pcENS1, encoding the C-terminal from E protein plus the NS1 region; pcENS1ANC, similar to pcENS1 plus the N-terminal sequence from NS2a (ANC); pcTPANS1, coding the t-PA signal sequence fused to NS1; and pcTPANS1ANC, similar to pcTPANS1 plus the ANC sequence. The NS1 was detected in lysates and culture supernatants from pcTPANS1-, pcENS1- and pcENS1ANC-transfected cells and not in cells with pcTPANS1ANC. Only the pcENS1ANC leads the expression of NS1 in plasma membrane, confirming the importance of ANC sequence for targeting NS1 to cell surface. High levels of antibodies recognizing conformational epitopes of NS1 were induced in mice immunized with pcTPANS1 and pcENS1, while only few pcENS1ANC-inoculated animals presented detectable anti-NS1 IgG. Protection against DENV-2 was verified in pcTPANS1- and pcENS1-immunized mice, although the plasmid pcTPANS1 induced slight higher protective immunity. These plasmids seem to activate distinct patterns of the immune system

    Spontaneous emission between an unusual pair of plates

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    We compute the modification in the spontaneous emission rate for a two-level atom when it is located between two parallel plates of different nature: a perfectly conducting plate (ϵ)(\epsilon\to \infty) and an infinitely permeable one (μ)(\mu\to \infty). We also discuss the case of two infinitely permeable plates. We compare our results with those found in the literature for the case of two perfectly conducting plates.Comment: latex file 4 pages, 4 figure

    Antimicrobial activity of phenolic compounds identified in wild mushrooms, SAR analysis and docking studies

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    Aim and Methods: Although the antimicrobial activity of extracts from several mushroom species have been reported, studies with the individual compounds present in that extracts are scarce. Herein, the antimicrobial activity of different phenolic compounds identified and quantified in mushroom species from all over the world was evaluated. Furthermore, a structure activity relationship (SAR) analysis and molecular docking studies were performed, in order to provide insights in the mechanism of action of potential antimicrobial drugs for resistant microorganisms. Results: 2,4-Dihydroxybenzoic and protocatechuic acids were the phenolic compounds with higher activity against the majority of Gram negative and Gram positive bacteria. Furthermore, phenolic compounds inhibited more MRSA than methicillin sensible Staphylococcus aureus. MRSA was inhibited by 2,4-dihydroxybenzoic, vanillic, syringic (MICs=0.5 mg/mL) and p-coumaric (MIC= 1 mg/mL) acids, while these compounds at the same concentrations had no inhibitory effects against methicillin sensible Staphylococcus aureus. Conclusions: The presence of carboxylic acid (COOH), two hydroxyl (OH) groups in para and ortho positions of the benzene ring, as also a methoxyl (OCH3) group in the meta position seems to be important for anti-MRSA activity. Significance and Impact of the Study: Phenolic compounds could be used as antimicrobial agents, namely against some microorganisms resistant to commercial antibiotics.Fundação para a Ciência e a Tecnologia (FCT, Portugal) and COMPETE/QREN/EU for financial support to this work (research project PTDC/AGR-ALI/110062/2009) and to CIMO (strategic project PEst-OE/AGR/UI0690/2011) and to PEst-OE/EQB/LA0016/2011. They also thank to CHTAD – Hospital Center of Trás-os-Montes e Alto Douro and Siemens for all the support

    Jabuticaba residues (Myrciaria jaboticaba (Vell.) Berg) are rich sources of valuable compounds with bioactive properties

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    The main environmental issue associated with compost production is the production of a liquid leachate. Leachate from municipal wastes contains carbon, nitrogen, phosphorus, potassium and trace elements that can be used as nutrients by plants. The advantages of the use of organic wastes such as compost leachate as fertilizers are evident. Their use would reduce the consumption of commercial fertilizers, which need, with their production, high cost and energy. This work aims to determine the physical and chemical properties of a specific leachate with a variable composition, collected from the composting line of a mechanical and biological treatment facility. The goal is to assess if the leachates can be used as a potential source for fertilizers, and thus develop and design a sequence of processes which could effectively convert the leachates to commercial fertilizers according to the requirements of the proposal of regulation of the European Parliament of 2016 for fertilizers. Preliminary results show that the leachate samples qualitatively meet the requirements established for the composition of commercial fertilizers, especially organo-mineral fertilizers. Furthermore, there is no production cost of leachate as a raw material. The results show that the leachate is characterized by manageable concentrations of heavy metals which can be removed by adsorption processes, and it presents suitable amounts of organic carbon after a water removal procedure. However, the establishment of the conditions for suitable conversion processes are still under investigation considering the high composition variability due to factors like storage and environmental conditions.info:eu-repo/semantics/publishedVersio

    Jabuticaba residues (Myrciaria jaboticaba (Vell.) Berg) are rich sources of valuable compounds with bioactive properties

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    Jabuticaba (Myrciaria jaboticaba (Vell.) Berg) is a Brazilian berry, very appreciated for in natura consumption. However, its epicarp is not normally consumed due to its stiffness and astringent taste, and in manufacture of products from jabuticaba fruit, it is responsible for the generation of large amounts of residues. The exploration of by-products is becoming important for the obtainment of valuable bioactive compounds for food and pharmaceutical industries. In this context, jabuticaba epicarp was studied regarding its chemical composition, namely in terms of phenolic compounds, tocopherols, and organic acids, and its bioactive properties, such as antioxidant, anti-proliferate, anti-inflammatory, and antimicrobial activities. A total of sixteen phenolic compounds, four tocopherols and six organic acids were identified in jabuticaba epicarp. Regarding bioactive properties, it showed high antioxidant activity, also presenting moderate anti-inflammatory, anti-proliferative, and antimicrobial activities. The extract did not present hepatotoxicity, confirming the possibility of its applications without toxicity issues.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2019); national funding by FCT, P.I., through the institutional scientific employment programcontract for M.I. Dias, L. Barros, and R.C. Calhelha contracts; C. Pereira contract though the celebration of program-contract foreseen in No. 4, 5 and 6 of article 23° of Decree-Law No. 57/2016, of 29th August, amended by Law No. 57/2017, of 19th July; and B. Albuquerque (SFRH/BD/136370/2018) PhD grant; to FEDER-Interreg España- Portugal programme for financial support through the project 0377_Iberphenol_6_E; the European Regional Development Fund (ERDF) through the Regional Operational Program North 2020, within the scope of Project NORTE-01-0145-FEDER-023289: DeCodE and project Mobilizador Norte-01-0247-FEDER-024479: ValorNatural®. The authors thank Dra. Cyanthia J. Kunigk (Instituto Mauá de Tecnologia, Brazil) for her collaboration.info:eu-repo/semantics/publishedVersio

    Phenolic profiling, biological activities and in silico studies of Acacia tortilis (Forssk.) Hayne ssp. raddiana extracts

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    The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES to CIMO (UIDB/00690/2020). L. Barros and R. C. Calhelha thank the national funding by the FCT, P.I., through the institutional scientific employment program-contract for their contracts. M. Carocho also thanks the project ValorNatural for his research contract. The authors are also grateful to the FEDER-Interreg España- Portugal programme for financial support through the project 0377_Iberphenol_6_E.info:eu-repo/semantics/publishedVersio

    Nutritional, chemical and bioactive profiles of different parts of a Portuguese common fig (Ficus carica L.) variety

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    This study aims to give an unprecedented contribution on the chemical composition and bioactivities of the most produced and appreciated Portuguese fig variety (“Pingo de Mel”) with the view of expanding the knowledge on its potentialities. An advanced characterization of its peel and pulp parts was carried out. Four free sugars (glucose, fructose, trehalose and sucrose), 5 organic acids (oxalic, quinic, malic, citric, and succinic acids), tocopherols in all their 4 forms, besides 23 fatty acids were detected in the samples. Fifteen different phenolic components were found in the peel hydroethanolic extract; whereas 12 were detected in the pulp hydroethanolic extract. Quercetin-3-O-rutinoside (rutin) was the major constituent of the peel, accounting for 33.8% of its phenolic content, followed by 5-O-caffeoylquinic acid and vanillic acid malonyl di-deoxyhexoside. Caffeic acid derivatives, such as caffeic acid hexosides, were the major components of pulp, followed by vanillic acid derivatives and O-caffeoylquinic acid. Both extracts displayed promising antioxidant capacities in all methods used, namely the 2,2-diphenyl-1-picrylhydrazyl radical-scavenging, the reducing power, the inhibition of β-carotene bleaching assays, the thiobarbituric acid reactive substances assay and the oxidative haemolysis inhibition assay; however, the peel presented significantly lower IC50 values than pulp. The extracts showed practically identical antibacterial capacities, being effective against methicillin-sensitive Staphylococcus aureus (MICs=2.5 mg/mL), besides methicillin-resistant S. aureus, Escherichia coli and Morganella morganii (MICs=5 mg/mL). The obtained results evidence that the fig peel is superior to the corresponding pulp as it relates to nutritional and phenolic profiles as well as bioactivities, endorsing the urgency in valorising and exploiting this usually discarded industrial by-product.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2019); national funding by FCT, P.I., through the institutional scientific employment programcontract for L. Barros, R. C. Calhelha, and M.I. Dias contracts, and Carla Pereira's contract though the celebration of program-contract foreseen in No. 4, 5 and 6 of article 23° of Decree-Law No. 57/2016, of 29th August, amended by Law No. 57/2017, of 19th July; to FEDER-Interreg España-Portugal programme for financial support through the project 0377_Iberphenol_6_E; the European Regional Development Fund (ERDF) through the Regional Operational Program North 2020, within the scope of Project NORTE-01-0145-FEDER-023289: DeCodE.info:eu-repo/semantics/publishedVersio

    Calluna vulgaris (L.) Hull: Chemical characterization, evaluation of its bioactive properties and effect on the vaginal microbiota

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    The inflorescences of Calluna vulgaris were nutritionally and chemically characterized. Furthermore, different organic and aqueous extracts were prepared for the evaluation of their bioactive properties. From the obtained results, carbohydrates were the major compounds, followed by protein, lipid and ashes. It was possible to identify the sugars fructose and glucose, five organic acids, 26 individual fatty acids and the four tocopherol isoforms. Concerning the extract composition, 12 phenolic compounds were identified, with myricetin-3-O-glucoside and myricetin-O-rhamnoside predominating. Concerning the bioactive effects, the more polar extracts showed not only the highest amount in phenolic compounds, but also the strongest antioxidant and antibacterial activities. In contrast, for the anti-inflammatory and cytotoxic potential, the most effective extracts were the n-hexane and the ethyl acetate extracts, respectively. C. vulgaris presented a wide range of biological effects, highlighting their capacity to inhibit pathogenic bacteria without affecting beneficial microflora, corroborating their use in traditional medicine.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support through CIMO (UID/AGR/00690/2013), CQ-VR (UID/QUI/00616/2013), and S. Heleno (SFRH/BPD/101413/2014) grants, and L. Barros and R. C. Calhelha contracts. The authors are also grateful to the FEDER-Interreg España-Portugal programme for financial support through the project 0377_Iberphenol_6_E. The authors are thankful to Dr Ana Maria Carvalho from the Instituto Politécnico de Bragança for her botanical expertise.info:eu-repo/semantics/publishedVersio

    Chemical features and bioactivities of cornflower (Centaurea cyanus L.) capitula: The blue flowers and the unexplored non-edible part

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    Cornflower is a flowering weed and ornamental plant whose blue flowers have been used for food, decorative and colouring purposes. In this study, the upper (edible flowers) and lower (non-edible receptacle and involucre) parts of the capitulum were studied and compared for their chemical composition and bioactive properties. The flowers were richer in tocopherols, organic acids, and apigenin derivatives (mainly apigenin-7-O-glucuronide-4′-O-(6-O-malonylglucoside)) than the non-edible bristly part (where syringic acid predominated). Four cyanidin derivatives were identified in the flowers. The extract of the non-edible part was more efficient in inhibiting the formation of thiobarbituric acid reactive substances (TBARS), the bleaching of β-carotene, and the haemolysis of the erythrocytes membrane. In general, the extracts were more active against Gram-positive bacteria and had no cytotoxicity against non-tumour liver PLP2 cells. Therefore, while flowers are a potential source of natural cyanidin-based colorants, the lower part of the capitulum has bioactive properties to be exploited in different food or pharmaceutical formulations.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO ( UID/AGR/00690/2013 ); to FCT for the grants of C.L. Roriz ( SFRH/BD/129551/2017 ) and C. Pereira ( SFRH/BPD/122650/2016 ) (awarded under the Programa Operacional Capital Humano (POCH) supported by the European Social Fund and National Funds of MCTES (Ministério da Ciência, Tecnologia e Ensino Superior) , and the research contracts of J. Pinela (Project AllNatt , POCI-01-0145-FEDER-030463 ) and L. Barros. This work is also funded by the European Regional Development Fund (ERDF) through the Regional Operational Program North 2020, within the scope of Project NORTE-01-0145-FEDER-023289: DeCodE and project Mobilizador Norte-01-0247-FEDER-024479: ValorNatural®; and FEDER-Interreg España-Portugal through the project 0377_Iberphenol_6_E.info:eu-repo/semantics/publishedVersio
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