ESTGV - DA - Artigo em revista científica, indexada ao WoS/Scopus
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- An easy way to Pb(Mg1/3Nb2/3)O3 synthesisPublication . Cruz-Lopes, Luísa; Segadães, Ana M.; Rocha, João; Pedrosa De Jesus, Júlio D.This work describes the very expeditious combustion synthesis of Pb(Mg1/3Nb2/3)O3 perovskite powders from mixtures of Pb(NO3)2, Mg(NO3)2·6H2O and Nb2O5, as cation precursors, and urea as fuel. The powders produced were characterized by XRD, SEM (EDS), and ICP and MAS NMR spectroscopies. Since, with this method, exposure to high temperatures is reduced to a minimum, the as-prepared combustion product shows no PbO loss. The % PMN in the as-prepared combustion powder is sensitive to, and increases with, the rise in the ignition temperature, and gets further improved upon calcination. However, the benefit of calcination, in terms of the reached maximum in the % PMN, becomes more modest when the ignition temperature is increased. Subsequent heat treatments of powder compacts in air (normal processing usually includes some kind of sintering step in order to improve crystallinity and densify the material), showed that over 90% Pb(Mg1/3Nb2/3)O3 can be readily obtained at 870°C.
- Application of Nanoparticles in Cancer Treatment: A Concise ReviewPublication . Sell, Mariana; Lopes, Ana Rita; Escudeiro, Maria; Esteves, Bruno; Monteiro, Ana R.; Trindade, Tito; Cruz-Lopes, LuísaTimely diagnosis and appropriate antitumoral treatments remain of utmost importance, since cancer remains a leading cause of death worldwide. Within this context, nanotechnology offers specific benefits in terms of cancer therapy by reducing its adverse effects and guiding drugs to selectively target cancer cells. In this comprehensive review, we have summarized the most relevant novel outcomes in the range of 2010–2023, covering the design and application of nanosystems for cancer therapy. We have established the general requirements for nanoparticles to be used in drug delivery and strategies for their uptake in tumor microenvironment and vasculature, including the reticuloendothelial system uptake and surface functionalization with protein corona. After a brief review of the classes of nanovectors, we have covered different classes of nanoparticles used in cancer therapies. First, the advances in the encapsulation of drugs (such as paclitaxel and fisetin) into nanoliposomes and nanoemulsions are described, as well as their relevance in current clinical trials. Then, polymeric nanoparticles are presented, namely the ones comprising poly lactic-coglycolic acid, polyethylene glycol (and PEG dilemma) and dendrimers. The relevance of quantum dots in bioimaging is also covered, namely the systems with zinc sulfide and indium phosphide. Afterwards, we have reviewed gold nanoparticles (spheres and anisotropic) and their application in plasmon-induced photothermal therapy. The clinical relevance of iron oxide nanoparticles, such as magnetite and maghemite, has been analyzed in different fields, namely for magnetic resonance imaging, immunotherapy, hyperthermia, and drug delivery. Lastly, we have covered the recent advances in the systems using carbon nanomaterials, namely graphene oxide, carbon nanotubes, fullerenes, and carbon dots. Finally, we have compared the strategies of passive and active targeting of nanoparticles and their relevance in cancer theranostics. This review aims to be a (nano)mark on the ongoing journey towards realizing the remarkable potential of different nanoparticles in the realm of cancer therapeutics.
- Application of nanotechnologies along the food supply chainPublication . Cruz-Lopes, Luísa; Macena, M.; Guiné, Raquel P. F.Nanoscience and nanotechnology are new fromtiers for this century. Nanotechnology translates into the ability to manipulate the material on a nanoscale. As in other sectors, recent developments in the fi eld of nanoscience and nanotechnology o ff er new opportunities for innovation for food. Nanofoods are considered foods grown, produced, processed or packaged using nanotechnological tools that incorporate nanomaterials to improve nutritional quality, taste or texture, and increase the shelf life of food. Nanotechnology ’ s applications are diverse, going from nanoencapsulated ingredients, such as bioactive compounds, nutrients and food additives that increase thebioavailability of the compounds, to ingredients that constitute nanostructures and nanotextures that provide barriers for physical - chemical protection, which allow modi fi cation of fl avour and odour. Also, has the potential to be used as biosensors to monitor food conditions during storage and transport, through packaging that includes indicators. This review covers the development and use of nanotechnology along the food supply chain, focusing the agricultural production, industrial processing and protection through packaging, as well as addressing the advantages and disadvantages of using this technology.
- Artificial Weathering of Heat-treated Pines from the Iberian PeninsulaPublication . Esteves, Bruno; Herrera, René; Santos, Jorge; Carvalho, Luisa; Nunes, Lina; Ferreira, José; Domingos, Idalina; Cruz-Lopes, LuísaSamples from the two most common pines grown in Portugal (Pinus pinaster Ait) and Spain (Pinus radiata, D. Don) were heat-treated in industrial facilities in accordance with ThermoWood ® class D. For both species, the variation in surface properties, of untreated and heat-treated wood after artificial weathering from 75 to 750 h, is presented. The analysis included the determination of color, roughness, gloss, and wettability before exposure and after each artificial weathering period. Untreated woods became darker faster, while in heat-treated woods, lightness remained approximately constant until 750 h of artificial weathering. Both untreated and heat-treated wood became more reddish in the beginning of the weathering process, turning greener for longer exposure times. Untreated woods became yellower in the beginning, turning into blueish tones later. Heat-treated wood turned slightly yellower until 750 h of weathering. Gloss decreased for untreated wood with no significant changes in heat-treated wood. Despite the changes, the gloss of both untreated and heat-treated wood converged to similar values. Roughness increased for both untreated and heat-treated woods. Artificial weathering increased the wettability of heat-treated wood.
- Aspects concerning the acoustical performance of school buildings in PortugalPublication . Pinho, P.G.; Pinto, M.; Almeida, Ricardo; Lopes, S.M.; Lemos, L.T.Acoustic measurements were performed in eight schools of different levels of education (from kindergarten to college) located in Viseu – Portugal. The acoustic evaluation was made in order to analyze the most common problems that may condition the acoustic environment inside school building. The acoustics evaluation of school buildings was made by the measurement of: reverberation time in classrooms; sound insulation between classrooms and between classrooms and corridors; impact sound insulation of floors and airborne sound insulation of façade. The sound insulation of façade was made with all elements closed and with natural ventilation conditions (banners or windows tilt mode). It was found that most of the studied cases revealed disabled constructive aspects in relation to the acoustic requirements of school buildings compromising the quality of education.
- Calorific Power Improvement of Wood by Heat Treatment and Its Relation to Chemical CompositionPublication . Domingos, Idalina; Ayata, Umit; Ferreira, José; Cruz-Lopes, Luísa; Sen, Ali; Sahin, Sirri; Esteves, BrunoChemical composition influences the calorific power of wood, mainly due to the calorific power of structural compounds and extractives. Heat treatment changes the chemical composition of treated wood. This work studies the relationship between chemical composition and calorific power improvement by heat treatment. Samples were heat-treated by the ThermoWood process ® for 1 h and 2 h. High heating value (HHV) and chemical composition; lignin, cellulose, hemicelluloses and extractives in dichloromethane, ethanol, and water were determined. The HHV of untreated wood ranged between 18.54–19.92 MJ/kg and increased with heat treatment for all the tested species. A positive linear correlation was found between HHV and Klason lignin (R2 = 0.60). A negative trend was observed for holocellulose, cellulose, and hemicelluloses content against HHV, but with low determination coefficients for linear regression. The best adjust for polysaccharides was found for hemicelluloses content. A positive correlation could be found for dichloromethane extractives (R2 = 0.04). The same was obtained in relation to ethanol extractives with R2 = 0.20. For water and total extractives, no clear positive or negative trends could be achieved. The results showed that the HHV of wood increased with heat treatment and that this increase was mainly due to the increase in lignin content.
- Carbon footprint calculator for the Portuguese textile and clothing industry: development, application and validationPublication . C. Duarte; Ferreira, José; Lopes Brás, Isabel Paula; Ferreira Silva, Maria Elisabete
- Carbon Footprint of Tourism Sector in Portugal Calculator DevelopmentPublication . Fernandes, Marco; Neves, Pedro; Araújo, Patrícia; Brás, Isabel; Ferreira Silva, Maria ElisabeteA carbon footprint (CF) calculator was developed to apply to a Portuguese touristic accommodation to contribute to a sustainable touristic activity. Although some calculators are available online, they are related to the country reality or use outdated emission factors. A calculator based on national emission factors is important. The calculator was developed in Microsoft Excel (version 365) and is based on the CO2e emissions resulting from electricity, water, fuels and food use, laundry and waste production. The calculator development involved: study the accommodation emission sources, selection the environmental indicators, determination of the emission factors and development of the CF formulas. Total CF calculation was made considering the partial CF per component, a monthly and annual comparison of each indicator’s emissions contribution using graphs. The emissions amount per overnight stay, per room, per area, were also assessed and these values were transformed into global hectare (gha). Avoided emissions calculation gives the information about the efforts in CF reduction, and two indicators were considered: electricity production from renewable energy sources and the amount of separated waste for recycling. It was considered reforestation measures to achieve carbon neutrality. This calculator incorporates four components not often used: water, laundry, waste, food, and avoided emissions.
- Changes in the content and composition of the extractives in thermally modified tropical hardwoodsPublication . Esteves, Bruno; Ayata, Umit; Cruz-Lopes, Luísa; Brás, Isabel; Ferreira, José; Domingos, IdalinaChemical composition of wood is known to change during thermal treatments. Two species grown in Turkey, afrormosia (Pericopsis elata) and duka (Tapirira guianensis) were heat treated according to Thermowood® method. Lignin, cellulose, hemicelluloses and extractives in dichloromethane, ethanol and water were determined. Wood extracts were analysed by gas chromatography with mass detection and existing compounds were identified by NIST17 database. Results show that hemicelluloses and cellulose content decreased for both heat-treated woods along the treatment while lignin percentage increased. The analysis of extractives has shown several compounds normally associated to lignin thermal degradation that increased along the treatment. At the same time several compounds associated to carbohydrate thermal degradation were found in all the extracts for both heat-treated woods. These founding have allowed the understanding of the degradation pattern of wood during thermal modification. There was not much difference between afrormosia and duka woods structural compounds behaviour along thermal modification. However, the variation of the amount of extractives along the treatment depended on the species.
- Characterization of bacterial communities from Masseiras, a unique Portuguese greenhouse agricultural systemPublication . Becerra-Castro, Cristina; Lopes, Ana Rita; Teixeira, Sara; Silva, M. Elisabete F.; Pimenta, Elisabete; Manaia, Célia M.; Nunes, Olga‘‘Masseiras’’ is an ancient Portuguese agriculture system, where soil was developed from sand dunes enriched with seaweeds over more than a century. Due to the importance for the local economy, this system evolved for greenhouse structures. In this study we compared the bacterial community composition and structure of ‘‘Masseiras’’ soil, aiming at assessing the potential impact of different agricultural practices. The bulk soil of two greenhouses (following or not the recommended agriculture good practices, FGP and NFGP, respectively) was compared based on their physicochemical properties and bacterial community. In both FGP and NFGP, Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Firmicutes, and Gemmatimonadetes were in a proportion of 5:1:1:1:1:1. However, the bacterial community of soil FGP was richer and more diverse than that of soil NFGP. Members of the classes Bacilli and Gemm-1, with higher relative abundance in NFGP and FGP, respectively, were those contributing most for distinguishing the bacterial communities of both soils. The differences in the structure of the bacterial communities correlated (Mantel test) with some soil physicochemical properties, such as electrical conductivity and nitrate and Zn contents, which were significantly higher in soil NFGP than in soil FGP.