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- The contribution of a portion of meat, fish and eggs for climate changePublication . Ferreira, Vicente; Domingos, Idalina; Esteves, Bruno; Cruz-Lopes, LuísaIntrodução: A mudança nos padrões alimentares dos cidadãos implicará uma pegada ambiental maior em termos de emissões de gases de efeito estufa e uso de recursos naturais. Por exemplo, dietas ricas em leite e carne, especialmente de ruminantes, estão associadas ao aumento das emissões de metano da fermentação entérica, do dióxido de carbono da deflorestação para dar origem ao pasto e do óxido nitroso da produção de ração. Objetivos: Para um consumo mais sustentável, o objetivo deste estudo foi quantificar e comparar a contribuição para as alterações climáticas de uma porção do que se come em geral, proveniente da Roda dos Alimentos, relacionados com carnes, aves, peixes e ovos, para alcançar uma dieta equilibrada e saudável. Métodos: A Avaliação do Ciclo de Vida, baseada nas normas ISO 14040/44 (2006), foi a metodologia utilizada. A análise de inventário e, posteriormente a análise de impacte foram realizadas utilizando o software SimaPro 8.5. O método escolhido para a avaliação de impacte ambiental foi o IPCC 2013 GWP 100a. Resultados: Os resultados mostram que uma porção de cavala (peixe) apresenta a pegada ecológica inferior seguida da porção de bacalhau, frango, lombo de porco, ovos, lagosta e bife de vaca, respetivamente. Conclusões: A principal conclusão deste estudo é que a avaliação do impacte de ciclo de vida usando o método IPCC 2013 GWP 100a, pode ajudar as pessoas a escolherem os melhores alimentos para uma refeição mais amiga do ambiente, ajudando a mitigar as alterações climáticas.
- Nanopartículas no tratamento da doença de alzheimerPublication . Cruz-Lopes, Luísa; Lopes, Ana; Escudeiro, Maria; Duarte, Cláudia; Ferreira, Rafaela; Graça, Francisco; Silva, Isaura; Esteves, BrunoIntrodução: A Doença de Alzheimer é uma patologia neurodegenerativa primária, de etiologia desconhecida e influenciada por vários fatores com aspetos neuropatológicos e neuroquímicos característicos. Atualmente, os fármacos aprovados para o tratamento desta doença apenas permitem aliviar os sintomas sendo acompanhados por diversos efeitos secundários. A nanotecnologia aparece como alternativa para o tratamento do Alzheimer, por oferecer muitas vantagens para a medicina contemporânea permitindo um diagnóstico e tratamento não invasivos e direcionados, reduzindo as reações adversas e os efeitos sistémicos. Objetivo: Reconhecer as potencialidades do uso de nanopartículas no tratamento da Doença de Alzheimer, identificando os tratamentos mais promissores e quais os seus possíveis efeitos secundários. Métodos: Revisão bibliográfica narrativa a partir de consulta a bases de dados como Science Direct, Web of Science, PubMed e Scielo. Resultados: As nanopartículas de ouro mostram-se capazes de atravessar a barreira hematoencefálica (BHE), carregando fármacos essenciais para a inibição da agregação dos péptidos Aβ, bem como dissolver fibrilhas pré-existentes. Polímeros biodegradáveis e biocompatíveis, como o polilactídeo poliglicólico (PLGA), constituem uma abordagem promissora e segura, tendo sido muito utilizados. As melhores técnicas são aquelas que garantem que as nanopartículas são capazes de atravessar a barreira hematoencefálica (BHE), atingir o seu alvo terapêutico, bem como garantir que estas partículas não induzem efeitos tóxicos no organismo. Apesar das nanopartículas serem capazes de tratar algumas doenças de forma eficiente, pouco se conhece sobre os seus efeitos secundários, estes poderão ou não ser mais danosos para o organismo do que a doença que pretenderam tratar. Conclusão: Existem várias abordagens terapêuticas promissoras, porém nenhuma ainda aprovada, uma vez que é difícil manter concentrações adequadas de fármaco no espaço intraneuronal. Estabelecer a dose tóxica é necessário para o uso aprovado de uma nanopartícula num tratamento, porém é quase impossível prever os seus efeitos citotóxicos em regiões extra-neuronais.
- Evolution of land use environmental impact of eucalyptus globulus in the context of life cycle assessmentPublication . Ferreira, José; Esteves, Bruno; Domingos, IdalinaIntroduction: The eucalyptus globulus forest area in Continental Portugal has shown a systematic increase over the last 50 years. In 20015 it was the species with the highest forest land occupation representing 26.2% of the total Portuguese forest area. Although between 2005 and 2015 the occupation of the soil by eucalyptus globulus had grown about 7.5%, the existing volume increased slightly 0.2%. The wildfires had a strong impact on this with a total burnt area of 1.1 million hectares during this period. Objective: Due to its economic value (national leader in exports of high added value) and social (contributes to the generation of thousands of jobs) this study aims to assess the evolution of the environmental impact of eucalyptus globulus on the land use between 2005 and 2015. Methods: The life cycle assessment methodology is followed and the ILCD 2011 Midpoint+ method available in the SimaPro software was chosen to assess the land use environmental impact. Results: Land use impact category of 1 m3 of eucalyptus globulus trees, standing, in forest, was 21832 Kg C deficit in 2005 and 23430 Kg c deficit in 2015 that means an increased about 7.3% during this period. Conclusion: Transformation to forest road (from natural forest) is the process that most contributes for the land use impact with approximately 78%. Forest occupation is the second most important process representing about 19.5% of the total impact category and forest road occupation represents only 3%.
- Avaliação de impacte ambiental da gestão de resíduos da produção de uma bancada com base na abordagem de ACVPublication . Silva, Luiza; Ferreira Silva, Maria Elisabete; Brás, Isabel; Domingos, Idalina; Ferreira Wessel, Dulcineia; Ferreira, JoséIntroduction: Consumerism has led to an increase in environmental problems, and for this reason, sustainable solutions must be the priority when designing new products or services. Life Cycle Assessment (LCA) is one of the most important analytical tools available for choosing the best decision when it comes to sustainability. Objective: The focus of this study was to apply an LCA to the management of wastes from a kitchen/bathroom countertop production. The waste management scenarios studied were landfill (current practice) and waste recycling. The panel consists of a ceramic layer on a lamellar panel substrate, formed by glassliner and PVC, which is intended to be resistant to water, scratches and impacts. The residues generated from the panel production are glassliner and PVC plastics and ceramics. Methods: The LCA methodology was followed and the EPD 2018 method available in the SimaPro software was chosen to quantify the environmental impacts of waste management. The environmental impact categories studied were eutrophication, global warming, photochemical oxidation, ozone layer depletion, abiotic depletion and acidification. Results: The results showed that the two plastic wastes are the main contributors to acidification, eutrophication and global warming. However, for photochemical oxidation and water scarcity, the ceramic component residue is the main contributor. Comparing the two scenarios, waste recycling reduces the impacts in all environmental impact categories, in comparison with landfill. Conclusion: Recycling the residues from the production of panels brings improvements in environmental impacts in all categories analyzed.
- A Influência da Prensagem a Quente nas Propriedades dos Painéis de Fibras de Alta Densidade, Aquando do seu Revestimento por PelículasPublication . Domingos, Idalina; Almeida, Paula; Esteves, Bruno; Ferreira, JoséUm conjunto de painéis de fibras de alta densidade, colados com uma resina de melamina/ureia-formaldeído, foi submetido a operações de prensagem a quente, de modo a estudar a influência desta operação nas propriedades do substrato. Usou-se uma prensa de pratos, a uma pressão que permitisse um contacto firme entre os painéis e os pratos da prensa. Foi desenvolvido um plano experimental para três temperaturas diferentes de 95, 180 e 210 º C e dois tempos de prensagem, de 22 e 35 segundos, para cada uma delas. Os painéis foram fabricados com fibras de pinho (Pinus pinaster) a uma densidade média de 930 kg/m3 e espessura média de 6,7 mm De acordo com os resultados obtidos, as operações de pós-fabrico dos painéis de alta densidade resultaram numa ligeira melhoria do módulo de elasticidade, da tensão de rotura à flexão estática e da resistência interna dos painéis usados como substrato. Observou-se também uma ligeira diminuição da humidade de equilíbrio e espessura dos painéis, bem como um aumento da densidade e do inchamento, com o aumento da temperatura e tempo de prensagem.
- Pine wood modification by heat treatment in airPublication . Esteves, BrunoMaritime pine (Pinus pinaster) wood has low dimensional stability and durability. Heat treatment was made in an oven using hot air during 2 to 24 h and at 170-200 ºC. A comparison was made against steam heat treatment. The equilibrium moisture content and the dimensional stability (ASE) in radial and tangential directions were evaluated at 35%, 65% and 85% relative humidity. MOE, bending strength and wettability were also determined. At the same mass loss improvements of equilibrium moisture content and dimensional stability were higher for oven heat treatment but the same happened for mechanical strength degradation. A 50% decrease in hemicellulose content led to a similar decrease in bending strength.
- Wood modification by heat treatment: a reviewPublication . Esteves, BrunoWood heat treatment has increased significantly in the last few years and is still growing as an industrial process to improve some wood properties. The first studies on heat treatment investigated mainly equilibrium mois-ture, dimensional stability, durability and mechanical properties. Mass loss, wettability, wood color, and chemical transformations have been subsequently extensively studied, while recent works focus on quality control, modeling, and study the reasons for the improvements. This review explains the recent interest on the heat treatment of wood and synthesizes the major publications on this subject on wood properties, chemical changes, wood uses, and quality control.
- Heat induced colour changes of pine (Pinus pinaster) and eucalypt (Eucalyptus globulus) woodPublication . Esteves, BrunoHeat treatment of Pinus pinaster and Eucalyptus globulus wood was made by hot air in an oven during 2 to 24 h at 170-200 ºC and by steam in an autoclave during 2 to 12 h at 190- 210 ºC. The colour parameters L*, a* and b* were determined by the CIELAB method on radial, tangential and transverse sections for untreated and treated wood, and their variation with the treatment (ΔL*, Δa* and Δb*) were calculated in percent. In the untreated woods, for eucalypt wood lightness (L*) varied between 54.1- 63.8% with a* between 7.4-8.5 and b* 15.7-19.9, and for pine wood L* varied between 67.3-76.1%, a* between 6.9 -7.6 and b* 16.3 -24.1. With the heat treatment wood became darker, more for oven treatment (ΔL* about 50% for 4% mass loss), and at the same treatment conditions more for eucalypt wood. In general the contribution of the red colour (a*) and yellow (b*) decreased with the heat treatment. The transverse section darkened less in the two species and for both treatments, with small differences between radial and tangential sections. Lightness decrease was related to chemical changes, with good correlations with glucose (R2= 0.96), hemicelluloses (R2 = 0.92) and lignin (R2 = 0.86). As regards colour, the heat treatments showed an interesting potential to improve the wood quality for solid timber products from pine and eucalypt.
- Improvement of technological quality of eucalypt wood by heat treatment in air at 170-200ºCPublication . Esteves, BrunoEucalypt wood is a low value wood considered a non durable species with low dimensional stability, used almost exclusively for pulp and paper or as firewood. The heat treatment was made in an oven in the presence of oxygen during 2 to 24 h and temperatures of 170-200ºC. Mass loss with treatment, equilibrium moisture content, dimensional stability measured as ASE in radial and tangential directions and at 35%, 65% and 85% relative humidity, MOE, bending strength and wettability were determined. Mass loss increased with treatment time and temperature reaching 9.5% for wood treated at 190ºC for 24h. Equilibrium moisture content decreased more than 50% (at 35% relative humidity) reaching a maximum of 61% reduction. At higher air relative humidity the reduction was smaller, 49% and 38% at the most for 65% and 85% relative humidity. Dimensional stability (ASE) increased with maximum values of 88% and 96% in radial and tangential direction, respectively. The improvement was higher for lower relative humidity. There was a reduction on mechanical resistance with heat treatment especially for bending strength that decreased about 20% for 3% mass loss, reaching 60% for mass losses higher than 10%. MOE decreased with heat treatment the reduction was under 10% until 8% mass loss. The contact angle increased until 5% mass loss, decreasing slightly afterwards. Heat treatment was shown to be a useful method to improve the technological quality of eucalypt wood as regards dimensional stability allowing it to compete with higher cost woods for some applications.
- Influence of steam heating on the properties of pine (Pinus pinaster) and eucalypt (Eucalyptus globulus) woodPublication . Esteves, Bruno; Velez Marques, António; Domingos, Idalina; Pereira, HelenaHeat treatment of Pinus pinaster and Eucalyptus globulus woods, two important species in Portugal, was made in the absence of air by steaming, inside an autoclave, for 2 to 12h at 190 ºC to 210ºC. Mass losses increased with treatment time and temperature reaching 7.3% for pine and 14.5% for eucalypt wood. The wood behaviour with moisture was improved. The equilibrium moisture content decreased by 46% for pine and 61% for eucalypt, the dimensional stability increased (maximum anti-shrinking efficiency in the radial direction of 57% and 90% for pine and eucalypt respectively) and the surface wettability was lowered. In relation to mechanical properties, the modulus of elasticity was little affected (maximum decrease of 5% for pine and 15% for eucalypt) but the bending strength was reduced (by 40% at 8% mass loss for pine and 50% at 9% mass loss for eucalypt wood). The variation of properties was related to treatment intensity and mass loss but significant improvements could already be obtained for a 3-4% mass loss without impairing the mechanical resistance. The response of eucalypt was higher than that of pinewood. Heat treatment of eucalypt wood shows an interesting potential to improve the wood quality for solid timber products.