Browsing by Author "Esteves, Bruno"
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- Adhesives from liquefied eucalypt bark and branchesPublication . Esteves, Bruno; Cruz-Lopes, Luisa; Fernandes, Ana Paula; Martins, Jorge Manuel; Domingos, Idalina; Ferreira, José; Silva, Silvia Helena Fuentes; Labidi, JalelAdhesives made from lignin are one of the most promising alternatives to common ureaformaldehyde adhesives. One of the possible sources is from wood or bark liquefaction at low temperatures and pressure. The possibility of using forest wastes for the production of adhesives was the objective of this work. Eucalypt bark and branches are wastes produced in the company Pedrosa & Irmãos, which is a forest management company based in Portugal (Leiria). The wastes were liquefied with polyalcohols catalyzed by sulfuric acid. The water insoluble fraction of the liquefied material was used for the production of the bio-adhesive. Both fractions were characterized and the bonding performance of the bio-adhesive was tested by ABES. The bio-adhesives obtained from bark or branches were similar, exhibiting a bonding strength approximately half of the conventional UF resin.
- Agro-industrial wastes as building insulation materials: A review and challenges for Euro-Mediterranean countriesPublication . Cintura, Eleonora; Nunes, Lina; Esteves, Bruno; Faria, PaulinaThis study investigates the possibility of using agro-industrial wastes for building products, mainly focusing on their insulation properties. A classification of bio-wastes is provided, namely of the lignocellulosic ones and their features and properties are described. Information about three main topics is collected: world production and consumption of some crops already used as building materials, their chemical composition and their most studied properties. Since the considered materials are lignocellulosic and they have many common features, a com- parison is made. The aim is to have comparable information to support future research related to the production of eco-efficient indoor insulation boards. The result of this research is the choice of four different agro-industrial wastes produced in the Euro-Mediterranean Countries. This area was chosen as buildings typically have little or no insulation due to the regional mild climate; however, particularly with climate change, indoor hygrothermal comfort is poor. The collection of information allows some conclusions to be reached about the different bio- wastes already studied and identify gaps in the literature.
- Análise agroecológica de caroços de cereja liquefeitos utilizando FTIR-ATRPublication . Dulyanska, Y.; Esteves, Bruno; Guiné, Raquel; Ferreira, José; Domingos, Idalina; Lopes, Rogério; Lima, Maria; Correia, Paula; Fragata, Anabela; Ferreira, Manuela; Barroca, Maria João; Silva, Aida; Lopes, Luísa P. CruzA agroecologia, combina princípios ecológicos com práticas agrícolas, tem ganho crescente relevância no desenvolvimento de práticas sustentáveis. Esta área valoriza não apenas a produção eficiente de alimentos, mas também a utilização responsável e inovadora dos resíduos agrícolas. Neste contexto, a análise de produtos derivados de cultivos frutícolas, como a caroço de cereja (Prunus avium L.), mostra ser uma área promissora para a identificação de novas estratégias de valor acrescentado. O presente trabalho teve como objetivo analisar o material liquefeito de caroço de cereja doce (Prunus avium L.) e apresentar novas estratégias de valor acrescentado para as possíveis transformações deste produto. Utilizando a espectroscopia FTIR-ATR, foram investigados tanto o material liquefeito quanto os resíduos sólidos resultantes destas liquefações, além do material original de Prunus avium L. Os resultados obtidos demonstram que o material original e o resíduo sólido liquefeito apresentam espectros semelhantes, enquanto as principais diferenças foram observadas entre o material original e o material liquefeito. Estas diferenças indicam potenciais caminhos para o aproveitamento eficiente e sustentável dos resíduos, promovendo a valorização de subprodutos agrícolas e contribuindo para um modelo de produção mais ecológico e economicamente viável. Desta forma, este estudo insere-se na linha de pesquisas que visam fortalecer a sustentabilidade na agricultura, através da inovação e da otimização dos resíduos agrícolas.
- 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.
- 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.
- Avaliação do ciclo de vida - resenha histórica e perspetiva futuraPublication . Ferreira, José; Esteves, Bruno; Cruz-Lopes, Luísa; Domingos, IdalinaIntroduction: This article presents a historical review and future perspective of life cycle assessment (LCA), as a tool for environmental assessment of products. The first LCA studies, called REPA (Resource and Environmental Profile Analysis), were carried out in the United States of America (USA) in the early 70s of the last century and had as main motivation the aspects related to the environmental implications and the consumption of resources used in the packaging production. It was not until the mid-1980s that these studies began to be carried out in Europe through the Swiss Federal Laboratory for Testing and Investigating Materials (EMPA). Development: In the 90's there was a notable growth in LCA activities in Europe and the USA, namely in terms of harmonization of LCA methods and standardization activities carried out, respectively, by SETAC (Society of Environmental Toxicology and Chemistry) and ISO (International Organization for Standardization). As of the year 2000, countless international and regional organizations were created, with the objective of improving the credibility; acceptance and practice of LCA, as well as many computer tools (software and databases) were developed to support LCA studies. Conclusions: One of the main future challenges for LCA is its greater integration with other life cycle approaches, which have been emerged, as LCA studies have been increasingly well developed.
- 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.
- 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.
- Chemical characterization, bioactive and fuel properties of waste cork and phloem fractions from Quercus cerris L. barkPublication . Sen, Ali; Miranda, Isabel; Esteves, Bruno; Pereira, HelenaWaste biomass composed of cork-rich and phloem-rich granules obtained from the fractioning of Quercus cerris L. bark were characterized for bulk density, chemical composition, bio-active components, ash composition, and higher heating value. Bulk density of the fractions relate to their cork content and deceases with smaller particle size due to a cork enrichment in the finer particles. The bulk density may therefore be used as an indicator of suberin content of waste cork and phloem fractions. Waste cork fractions are rich sources of lipophilic and polar extracts while waste phloem fractions contain high amount of polar extracts. The polar extracts of both biomass fractions showed very high antioxidant capacities with IC50 values between 2.5 and 7.3 μg extract mL-1 for cork fractions and 5.8 and 11.7 μg extract mL-1 for phloem fractions. Higher heating values in waste cork fractions increase with decreasing particle size and ranged between 20 and 22 MJ kg-1. A biorefinery scheme was developed for the valorization of the waste cork and phloem fractions based on their physical, chemical, bioactive, and higher heating values
- Chemical Composition and Optimization of Liquefaction Parameters of Cytisus scoparius (Broom)Publication . Cruz-Lopes, Luísa; Almeida, Daniela; Dulyanska, Yuliya; Domingos, Idalina; Ferreira, José; Fragata, Anabela; Esteves, BrunoInvasive plants spread in such a way that they are threats to native species and to biodiversity. In this context, this work aims to determine possible valorizations of Scotch Broom Cytisus scoparius (L.) Link. This species harvested in the Viseu region was used in the present study. The eco-valorization of these renewable resources was made by conversion into liquid mixtures that can later be used in the manufacture of valuable products. For a better understanding of the results obtained, a chemical characterization of the Cytisus scoparius branches (CsB) was made. The ash content, extractives in dichloromethane, ethanol and water, lignin, cellulose and hemicellulose of the initial material were determined. Liquefaction was made in a reactor with different granulometry, temperatures and time. Results show that Broom is mainly composed of cellulose (36.1%), hemicelluloses (18.6%) and lignin (14.6%) with extractives mainly soluble in ethanol, followed by water and a small amount in dichloromethane. Ashes were around 0.69%, mainly composed of potassium and calcium. Generally, smaller size, higher solvent ratio, higher temperature and higher time of liquefaction lead to higher liquefaction. The highest percentage of liquefaction was 95% which is better than most of the lignocellulosic materials tested before.