2,326 research outputs found

    Potential of Portuguese propolis as source of biofungicides

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    Agriculture provides livelihoods for 40% of worldwide population1 . Due to the rapid human population growth, it is estimated that global food production will need to increase by 60% to feed over 9.8 billion people by 20502 . The use of pesticides contributes to high crop yields and effective farm management3 . Globally, 4.6 million tons of chemical pesticides are sprayed into the environment every year4,5. Out of the total consumption of pesticides, 17.5% are in the form of fungicides5 . Although efficient, these chemical controls have undesirable characteristics, such as the development of pathogen resistance, environmental pollution, long degradation periods, bioaccumulation in the food chain and toxicity to non-target organisms6 . Therefore, alternative paths to the intensive use of crop protection chemicals are needed, such as the use of natural products which are effective, biodegradable and leave no harmful residues. Propolis is a natural resinous mixture made by honeybees (particularly Apis mellifera L.) from various plant sources and bee wax. Hundreds of different compounds have been identified so far in propolis, including several bioactive compounds such as flavonoids and phenolic acids and terpene derivatives, generally associated to its antibacterial, antifungal, antiviral and antioxidant activities, among others7 . Previous work showed that propolis ethanol extracts (EEs) can be explored as source of biofungicides for application in a sustainable agriculture management 8. In this study we evaluated the antifungal activity of EEs from Portuguese propolis samples against a range of phytopathogenic fungal species that affect economically important crops in Portugal. Interestingly, results showed that different propolis samples have distinct fungitoxic activities but also that different fungi species exhibit distinct susceptibilitiesFEDER/COMPETE/POCI– Operational Competitiveness and Internationalization Programme, under Project POCI-01-0145-FEDER-006958 and National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UID/AGR/04033/201

    Essential oils encapsulated in zeolite structures as delivery systems (EODS): an overview

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    Essential oils (EO) obtained from plants have proven industrial applications in the manufacturing of perfumes and cosmetics, in the production and flavoring of foods and beverages, as therapeutic agents in aromatherapy, and as the active principles or excipients of medicines and pharmaceutics due to their olfactory, physical-chemical, and biological characteristics. On behalf of the new paradigm of a more natural and sustainable lifestyle, EO are rather appealing due to their physical, chemical, and physiological actions in human beings. However, EO are unstable and susceptible to degradation or loss. To tackle this aspect, the encapsulation of EO in microporous structures as zeolites is an attractive solution, since these host materials are cheap and non-toxic to biological environments. This overview provides basic information regarding essential oils, including their recognized benefits and functional properties. Current progress regarding EO encapsulation in zeolite structures is also discussed, highlighting some representative examples of essential oil delivery systems (EODS) based on zeolites for healthcare applications or aromatherapy.The authors are grateful for the national funds provided by the FCT (Foundation for Science and Technology, Portugal) under the projects UIDB/04050/2020 (CBMA) and PTDC/AAGTEC/5269/2014 (FEDER, European Fund for Regional Development)/COM PETE/POCI—Operational Competitiveness and Internationalization Programme under the project POCI-01-0145-FEDER-006958. They are grateful for the financial support provided by the Research Centers CQ/UM through UID/QUI/0686/2020 and Project BioTecNorte (operation NORTE-01-0145-FEDER-000004), supported by the Northern Portugal Regional Operational Programme (NORTE 2020) under the Portugal 2020 Partnership Agreement through the European Regional Development Fund.info:eu-repo/semantics/publishedVersio

    Development of a disposable paper-based potentiometric immunosensor for real-time detection of a foodborne pathogen

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    This work reports a new paper-based sensing platform and its application in a label-free potentiometric immunosensor for Salmonella typhimurium detection based on the blocking surface principle. A paper-based strip electrode was integrated with a filter paper pad which acted as a reservoir of the internal solution. The design offers a convenient platform for antibody immobilization and sampling, proving also that is a simple and affordable methodology to control an ionic flux through a polymer membrane. Two different immunosensing interfaces were assembled on the developed paper-strip electrode. The simplest interface relied on direct conjugation of the antibody to the polymer membrane and the second one resorted to an intermediate layer of a polyamidoamine dendrimer, with an ethylenediamine core from the fourth generation. Electrochemical impedance spectroscopy was used to assess the successive interface modification steps and the resulting analytical performance of both immunosensors was compared. For such, the potential shift derived from the blocking effect of the ionic flux caused by antigen-antibody conjugation was correlated with the logarithm of the Salmonella typhimurium concentration in the sample. In optimized conditions, a limit of detection of 5 cells mL-1 was achieved. As a proof-of-concept, the proposed method was applied to apple juice samples, demonstrating to be a suitable prototype to be used in real scenarios in useful time (<1 h assay).This work received financial support from the European Union and National Funds(FCT, Fundação para a Ciência e Tecnologia) through projects UID/QUI/50006/2019 and Norte-01-0145-FEDER-000011-RL1–QUALIFOOD. N.F.D Silva is grateful to FCT grant SFRH/BD/112414/2015, financed by POPH–QREN–Tipologia 4.1–FormaçãoAvançada,subsidizedbyFSEandMCTES.info:eu-repo/semantics/publishedVersio

    Comparative study of risk factors among children and adolescents with an anthropometric diagnosis of overweight or obesity

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    OBJETIVO: O excesso de peso é um grande problema de saúde pública em todo o mundo, atingindo crianças e adolescentes. O presente estudo teve por objetivo verificar se a condição de portador de sobrepeso se associa à presença de fatores de risco à saúde. MÉTODOS: Foram estudados 84 sujeitos entre seis e 17 anos, constituindo-se um grupo de 34 pacientes portadores de sobrepeso e outro de 50 obesos, atendidos em ambulatório de Nutrologia Pediátrica da Universidade de Ribeirão Preto (Unaerp), durante o período de outubro de 2004 a outubro de 2005. Foram obtidas as variáveis: pressão arterial, circunferência abdominal, glicemia de jejum, glicemia de segunda hora, colesterol total, HDL-c, LDL-c e triglicérides. Comparam-se os dois grupos por meio de duas abordagens estatísticas: comparação entre as distribuições dos valores absolutos (teste de Mann-Whitney) e entre as frequências de valores considerados alterados (teste exato de Fisher). RESULTADOS: Quanto à primeira abordagem, verificou-se diferença estatística apenas para o HDL-c, com maiores valores para o subgrupo de portadores de sobrepeso de seis a dez anos. Quanto à segunda comparação, verificou-se diferença estatística para a circunferência abdominal (segundo os critérios de Freedman), HDL-c e glicemia de jejum, com maiores frequências de valores alterados entre os obesos. CONCLUSÕES: Os portadores de sobrepeso apresentaram alterações indicativas de prejuízos à sua saúde, semelhantemente aos obesos, sendo necessário também incluí-los nos programas de prevenção e tratamento.OBJECTIVE: Excess weight is a serious public health problem all over the world, affecting children and adolescents. The objective of the present study was to determine whether the condition of being overweight is associated to changes in health parameters. METHODS: 84 subjects aged 6-17 years old were studied (34 overweight and 50 obese patients), all of them assisted at the Pediatric Nutrology outpatient clinic of the University of Ribeirão Preto (Unaerp) from October/2004 to October/2005. Arterial pressure, abdominal circumference, fast glycemia, second hour glycemia, total cholesterol and its fractions (HDL-c and LDL-c) and triglycerides were determined. The two groups were compared by two statistical approaches: comparison of absolute values by Mann-Whitney test, and between frequencies of altered values by Fisher exact test. RESULTS: There was a statistical difference only for HDL-c, with higher concentrations in the overweight group when the subgroup of patients with 6-10 years old was considered. Regarding the second approach, there were statistical differences in the abdominal circumference by Freedman criteria, HDL-c and fast glycemia, with higher frequencies of altered values among obese subjects. CONCLUSIONS: Overweight patients presented alterations harmful to their health, similarly to obese individuals. It is necessary to enroll overweight children and adolescents in programs dedicated to the prevention and treatment of nutritional problems

    Proposta metodológica para avaliação audiométrica e da incomodidade do ruído de baixa frequência

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    Esta pesquisa tem por objetivo apresentar uma proposta metodológica de avaliação da incomodidade ao ruído, que contribua para a discussão orientada, exclusivamente, para as baixas frequências. O estudo enquadra-se no âmbito de um projeto mais alargado e que se encontra em curso. Este projeto tem por objetivo compreender os impactes da poluição sonora de baixa frequência na qualidade de vida da população e na sustentabilidade dos lugares. A proposta metodológica compreende duas vertentes de análise: a componente objetiva e a subjetiva. A primeira abarca a medição dos níveis sonoros e a gravação do som. A segunda diz respeito à realização de testes audiométricos adaptados iniciados em março de 2016 e compostos por três etapas: a determinação do limiar de audição, a avaliação da incomodidade da exposição ao ruído (usando uma escala de Likert) e a realização de testes cognitivos. A realização dos testes audiométricos adaptados tiveram como base a ISO 8253-1. O procedimento de teste tem uma duração aproximada de 25 minutos. O limiar de audição para os sons puros apresenta intensidades sonoras distintas, sendo variável de indivíduo para indivíduo (variando entre 40 dB â 80 dB para a frequência de 18 Hz; 25 dB â 80 dB para 21 Hz; 40 dB â 75 dB para 39 Hz e 25 dB â 50 dB para 51 Hz). A média dos testes do limiar de audição para o som gravado é de 45 dB. A componente subjetiva de avaliação da incomodidade devida ao ruído é imprescindível para avaliar os impactes do ruído de baixa frequência na qualidade de vida da população.This research aims to present a methodology for assessing the discomfort to noise exposure, to contribute to the discussion focused exclusively for the low frequencies. The study falls within the scope of an ongoing larger research project. This project aims to understand the impacts of low frequency noise in the population's quality of life and sustainability of the places. The methodology comprises two forms of analysis: the objective and the subjective components. The first covers the measurement of sound levels and sound recording. The second concerns the implementation of adapted audiometric tests that was started in March 2016 and consisting of three stages: determining participants’ hearing thresholds, the evaluation of noise exposure discomfort and the application of cognitive tests. The development of adapted audiometric tests were based on ISO 8253-1. The test procedure has a duration of approximately 25 minutes. The hearing threshold for pure tones has different sound intensities, variable for individual to individual (ranging between 40 dB - 80 dB at the frequency of 18 Hz, 25 dB - 80 dB for 21 Hz, 40 dB - 75 dB to 39 Hz and 25 dB - 50 dB to 51 Hz). The average hearing threshold tests for the recorded sound is 45 dB. The subjective evaluation component of noise exposure discomfort is essential to assess the impact of low frequency noise in the population's quality of life

    Tailoring Organic-Organic Poly(vinylpyrrolidone) Microparticles and Fibers with Multiwalled Carbon Nanotubes for Reinforced Composites

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    Polymeric-based microparticles and fibers are tailorable for a wide range of common industrial and biomedical applications, while multiwalled carbon nanotubes (MWCNTs) are among the most useful macromolecules based on their outstanding electronic, mechanical, and optical properties at the nanoscale. If one combines these nanostructures with various polymeric precursors, their range of potential applications becomes even greater. One of the simplest and most affordable methods for fabricating micro- and nanostructures is electrospinning. Herein we demonstrate how MWCNTs may be used to produce tailor-made organic-organic poly(vinylpyrrolidone) (PVP) microparticles and fibers via electrospinning by studying their structural, vibrational, rheological, and mechanical properties' dependence on their solvent (ethanol (EtOH) or dimethylformamide (DMF)) and resulting morphology. Specifically, we find clear differences in morphologies from perfectly spherical and isolated microparticles to fibers mats, or a combination of fibers with entangled beads, with solvent type and concentration. On the basis of our findings, we propose that the mechanism governing the shape and size of the particles is a competition between the solvent's surface tension, dielectric constant, and viscoelastic properties. We show, based on both our experimental results and density functional theory (DFT) calculations, that OH functionalization of the MWCNTs is essential for achieving high PVP coverages and promoting the stability of the resulting PVP/MWCNT nanocomposite. Finally, by fabricating PVP/MWCNT fiber mats, we demonstrate that low concentrations (0.01-0.1 wt %) of MWCNTs led to a qualitative improvement (â250%) in the resulting mechanical properties, i.e., a reinforced composite. These results show how by controlling the solvent's dielectric constant, surface tension, and polymer concentration, one may produce tailor-made polymeric nanomaterials in combination with other organic/inorganic nanoparticles, i.e., silver, gold, or carbon allotropes, for next-generation applications

    Avaliação da imagem cognitiva e top of mind de Viana do Castelo: o caso do festival Vodafone Paredes de Coura

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    O objetivo principal deste trabalho foi avaliar a imagem cognitiva e Top of Mind do destino de Viana do Castelo durante o Festival Vodafone Paredes de Coura. O estudo empírico adotou uma abordagem quantitativa através da aplicação de um inquérito por questionário efetuado aos espectadores/visitantes do Festival Vodafone Paredes de Coura. Aplicaram-se 395 questionários, tendo-se assumido um erro amostral final de 4,9% e um nível de significância de 5%. Os resultados revelam que existe uma correlação entre a avaliação cognitiva do Festival Vodafone Paredes de Coura e a avaliação cognitiva do destino turístico Viana do Castelo. As respostas de evocação espontânea das memórias dos inquiridos, apontam como primeira localidade Top of Mind “Paredes de Coura”, seguindo-se “Viana do Castelo” e “Ponte de Lima”, descrevendo os atributos da região como sendo “bonito”, “verde” e “natureza”. Face às respostas da evocação espontânea das memórias, os inquiridos apontaram o Festival Vodafone Paredes de Coura como sendo o festival Top of Mind, descrevendo-o com atributos como “música”, “natureza” e “rio.The main objective of this work is to evaluate the cognitive image and Top of Mind destiny of Viana do Castelo during the Vodafone Paredes de Coura Festival. The empirical study adopted a quantitative approach through the application of a questionnaire survey made to viewers/visitors of the Vodafone Paredes de Coura Festival. A total of 395 questionnaires were applied, with a final sampling error of 4.9% and a significance level of 5%. The results reveal that there is a correlation between the cognitive evaluation of the Vodafone Paredes de Coura Festival and the cognitive evaluation of the Viana do Castelo tourist destination. The responses of spontaneous evocation of respondents, point “Paredes de Coura” as the first Top of Mind location, followed by “Viana do Catelo” and “Ponte de Lima”, describing the region’s attributes as “beautiful”, “green” and “nature”. Faced with the responses of the spontaneous evocation of memories, the respondents pointed to the Vodafone Paredes de Coura Festival as the Top of Mind Festival, describing it with attributes such as “music”, “nature” and “river”.Este estudo foi realizado no Centro de Investigação em Ciência Política (UID/CPO/00758/2013), Universidade do Minho e apoiado pela Fundação para a Ciência e a Tecnologia e pelo Ministério da Educação e Ciência através de fundos nacionais. Os autores agradecem os contributos e a participação no trabalho de investigação da investigadora Lucília Maria Ferreira Alves Cardoso ([email protected]) da Universidade de Vigo.info:eu-repo/semantics/publishedVersio

    Differences in chemical composition and antioxidant activity of three propolis samples collected in the same apiary

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    Financial support provided by FCT (PD/BD/128276/2017), under the Doctoral Programme Agrichains - PD/00122/2012

    Operational research IO 2021—analytics for a better world. XXI Congress of APDIO, Figueira da Foz, Portugal, November 7–8, 2021

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    This book provides the current status of research on the application of OR methods to solve emerging and relevant operations management problems. Each chapter is a selected contribution of the IO2021 - XXI Congress of APDIO, the Portuguese Association of Operational Research, held in Figueira da Foz from 7 to 8 November 2021. Under the theme of analytics for a better world, the book presents interesting results and applications of OR cutting-edge methods and techniques to various real-world problems. Of particular importance are works applying nonlinear, multi-objective optimization, hybrid heuristics, multicriteria decision analysis, data envelopment analysis, simulation, clustering techniques and decision support systems, in different areas such as supply chain management, production planning and scheduling, logistics, energy, telecommunications, finance and health. All chapters were carefully reviewed by the members of the scientific program committee.info:eu-repo/semantics/publishedVersio
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