Ciências e Tecnologia | Artigos em revistas internacionais / Papers in international journals
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- First chemical profile analysis of acacia podsPublication . Pedro, Soraia I.; Luís, Ângelo; Antunes, Alexandra M. M.; Gonçalves, José C.; Gominho, Jorge; Gallardo, Eugenia; Fernandes, Tiago; Anjos, OféliaThis study intended to evaluate the potential industrial applications of various Acacia species (Acacia melanoxylon, Acacia longifolia, Acacia cyclops, Acacia retinodes, Acacia pycnantha, Acacia mearnsii, and Acacia dealbata) by examining their chemical composition, antioxidant, and antimicro bial properties. Using high-resolution mass spectrometry, a comprehensive analysis successfully identified targeted compounds, including flavonoids (flavonols/flavones) and phenolic acids, such as 4-hydroxybenzoic acid, p-coumaric acid, and ellagic acid. Additionally, p-coumaric acid was specifically identified and quantified within the hydroxycinnamic aldehydes. This comprehensive characterization provides valuable insights into the chemical profiles of the studied species. Among the studied species, A. pycnantha exhibited a higher concentration of total phenolic compounds, including catechin, myricetin, quercetin, and coniferaldehyde. Furthermore, A. pycnantha displayed notable antibacterial activity against K. pneumoniae, E. coli, S. Typhimurium, and B. cereus. The identi fied compounds in Acacia pods and their shown antibacterial activities exhibit promising potential for future applications. Moreover, vibrational spectroscopy was a reliable method for distinguishing between species. These significant findings enhance our understanding of Acacia species and their potential for various industrial applications.
- Sulfonyldibenzoate coordination polymers as bioactive dopants for polysaccharide films with antibacterial and antibiofilm propertiesPublication . Fernandes, Tiago; Macedo, Filipa; Cabral, Rafaela G.; Guiu, Telma; Franco, Chris H. J.; Jorge, Paula; Sousa, Ana Catarina; Anfré, Vânia; Cerca, Nuno; Kirillov, Alexander M.This work describes the preparation, characterization, and antimicrobial properties of bioactive silver(I) and copper(II) coordination polymers (bioCPs) and derived biopolymer materials. Two bioCPs, [Ag2(μ6-sdba)]n (1) and [Cu(μ4-sdba)H2O]n·1.5nH2O (2), were assembled from metal salt precursors and 4,4′-sulfonyldibenzoic acid (H2sdba). Both compounds were used as dopants for preparing hybrid biopolymerfilms based on agarose (AGR) or potato starch (PS) as model polysaccharide biopolymers with varying rates of degradability and silver/copper release. BioCPs and derived biopolymer films (1@[AGR]n, 2@[AGR]n, 1@[PS]n, and 2@[PS]n) with a low loading of dopant (1–5 wt%) show promising antibacterial activity against Gram-positive (S. aureus and S. epidermidis) and Gram-negative (E. coli and P. aeruginosa) bacteria. Silver doped biopolymer films also totally impair the formation of bacterial biofilms, with undetectable biofilm cells in several cases (∼7.5 log or 99.99999% inhibition). By reporting new bioCPs and biopolymer films obtained from renewable polysaccharides, this multidisciplinary work extends the application of coordination compounds as components of hybrid functional materials with antimicrobial properties and prospective biomedical relevance.
- The interplay of bottle storage and wood ageing technology: volatile and sensory profiles of wine spirits aged with chestnut woodPublication . Anjos, Ofélia; Caldeira, Ilda; Vitória, Cláudia; Alves, Sheila Oliveira; Fernandes, Tiago; Canas, Sara; Catarino, SofiaWine spirits are typically aged in wooden barrels. Recently, alternative ageing technologies, such as those using wood fragments in wine spirits stored in stainless steel tanks, have been investigated. However, a signifcant lack of information regarding the potential evolution of these beverages after bottling still remains. This study assessed the 12-month evolu tion of aroma in bottled wine spirits aged with chestnut wood using diferent technologies, including fragment application with several micro-oxygenation strategies and barrels (traditional). Chemical analysis using GC-FID and GC–MS methods, along with sensory analysis, was conducted on all sampled aged wine spirits. Signifcant changes in volatile compounds were detected over time, including volatile phenols, acids, and esters. Multivariate data analysis distinguished traditional and alternative aged samples, with slight sample discrimination based on bottle storage. Regarding the sensory results, a signifcant efect of the time in bottle in several sensory attributes was found, while the ageing technologies mainly afected the gustatory attributes. The tasters were also asked to rate the overall quality of the samples, which seems to be favoured by the time in the bottle. This initial assessment of the impact of 1 year of glass bottle storage on the volatile and sensory composition of aged wine spirits highlights that this stage must be considered as an additional technological factor in their production process. However, the diferences induced by the wood ageing technologies applied remained evident after 1 year of glass bottle storage.
- Do people adapt to where they live?: a comparative analysis of perceived physical urban pleasantness using a quantitative modelPublication . Medina Monteiro, João Pedro; Sousa, Nuno; Natividade-Jesus, Eduardo; Coutinho-Rodrigues, João; Oliveira, Leise Kelli; Santos, Patrícia da SilvaThis article examines the question of whether people perceive their own urban environment more favourably than people from other urban environments, i.e., whether residents, in a sense, adapt to where they live. To analyse this question, a quantitative statistical model that uses geometric and land use elements was applied to a case study of Belo Horizonte, Brazil, to estimate the perception of physical pleasantness of the urban environment using two calibrations: a global one and one obtained from a survey carried out in Belo Horizonte. The article then contrasts findings specific to Belo Horizonte with global perceptions, highlighting that local residents tend to evaluate their city's geometry and land use more positively than a worldwide audience. This difference suggests that familiarity and acclimatisation to the urban environment can significantly influence residents’ perceptions of their physical living environment.
- Sisal-derived acid-char molybdenum catalyst for reductive deoxygenation of sulfoxidesPublication . Duarte, Tiago A. G.; Mestre, Ana S.; Ferreira, Maria J. G.; Rego, Ana M. Botelho do; Ferraria, Ana M.; Kirillova, Marina V.; Carvalho, Ana P.; Calhorda, Maria José; Fernandes, TiagoThe deoxygenation of sulfoxides is a rather important reaction from both synthetic and biological points of view, due to the potential of sulfides as intermediates in a variety of processes. Homogenous Mo-based catalysts successfully perform the reduction of diphenyl sulfoxide to diphenyl sulfide with high yields but present the well-known limitations regarding recovery and recycling. Thus, in the present work, two new supported catalysts were prepared through the immobilization of molybdenum precursor species (dichlorodioxodi(aquo)molybdenum(VI) and sodium molybdate), onto a sisal-derived acid-char (S13.5), obtained from rope industry wastes by acid-mediated carbonization. The heterogeneous Mo-based materials were characterized by IR spectroscopy, elemental analysis, ICP, solid state NMR, XPS, and SEM, and were evaluated as catalysts for the reduction of sulfoxides to sulfides in the presence of phenylsilane as reducing agent under different reaction conditions. The influence of various experimental parameters, including reducing agent type and amount, solvent type, and acid promoter were investigated. Catalytic studies revealed that both catalysts deoxygenate sulfoxides at 120 °C in toluene solution with high yields (up to 97%). The MoO2Cl2 derived catalyst shown to be highly efficient in the reduction of diaryl, alkylaryl, dibenzyl, and dialkyl sulfoxides to the corresponding sulfoxides using phenylsilane as reductant and no need of acid promoter.
- Face-to-face interactions estimated using mobile phone data to support contact tracing operationsPublication . Cumbane, Silvino; Gidófalvi, Gyözö; Cossa, Osvaldo; Madivadua Júnior, Afonso; Branco, Frederico; Sousa, NunoUnderstanding people’s face-to-face interactions is crucial for effective infectious disease management. Traditional contact tracing, often relying on interviews or smartphone applications, faces limitations such as incomplete recall, low adoption rates, and privacy concerns. This study proposes utilizing anonymized Call Detail Records (CDRs) as a substitute for in-person meetings. We assume that when two individuals engage in a phone call connected to the same cell tower, they are likely to meet shortly thereafter. Testing this assumption, we evaluated two hypotheses. The first hypothesis—that such co-located interactions occur in a workplace setting—achieved 83% agreement, which is considered a strong indication of reliability. The second hypothesis—that calls made during these co-location events are shorter than usual—achieved 86% agreement, suggesting an almost perfect reliability level. These results demonstrate that CDR-based co-location events can serve as a reliable substitute for in-person interactions and thus hold significant potential for enhancing contact tracing and supporting public health efforts.
- Walking and cycling friendliness as proxies to retrofit active transport infrastructurePublication . Pais, Filipe; Sousa, Nuno; Jesus, Eduardo Natividade; Rodrigues, João CoutinhoActive transport modes, such as walking and cycling, have been promoted by scientific studies and policymakers due to congestion-reduction and health benefits, and low environmental impact. However, adequate infrastructure is necessary for citizens to exercise their choice for those modes. This article presents a case study on the active mode infrastructural condition of a city which, as many others, privileged motorized modes in its growth during the 20th century. Using walking and cycling friendliness as evaluators of the infrastructural condition and a Geographic Information System environment as the calculational tool, an accessibility-based analysis was carried out that enables policymakers to identify the main issues affecting those modes and, most importantly, to pinpoint specific problems that are common to both modes. The methodological approach is scalable to any city size and is a decision-aid tool that can provide value mainly by identifying those common problems which can be efficiently addressed in future infrastructural improvements and maintenance actions. For the case study, common problems turn out to lay along large, distributor roads which fail to provide active travellers with adequate safety from traffic. Based on the results, a concrete intervention plan is proposed, for which a cost-benefit analysis was carried out.
- Does fake news have feelings?Publication . Laroca Mendes Pinto, Herbert; Rocio, Vitor; Cunha, AntónioFake news spreads rapidly, creating issues and making detection harder. The purpose of this study is to determine if fake news contains sentiment polarity (positive or negative), identify the polarity of sentiment present in their textual content and determine whether sentiment polarity is a reliable indication of fake news. For this, we use a deep learning model called BERT (Bidirectional Encoder Representations from Transformers), trained on a sentiment polarity dataset to classify the polarity of sentiments from a dataset of true and fake news. The findings show that sentiment polarity is not a reliable single feature for recognizing false news correctly and must be combined with other parameters to improve classification accuracy.
- Hybrid teaching and learning in higher education: a systematic literature reviewPublication . Gudoniene, Daina; Staneviciene, Evelina; Dieng, Djibril; Degroote, Joël; Butkiene, Rita; Huet, Isabel; Dickel, Jochen; Rocio, Vitor; Casanova, DiogoHybrid teaching, which integrates traditional in-person learning based on students’ perspectives where online learning offers a flexible approach to education, combines the benefits of technology with face-to-face interactions. Moreover, teaching and learning in a hybrid way met several challenges for both teachers and learners, including technological problems, time management, communication difficulties, and assessment complexities. This systematic review investigates six main research questions: (1) What pedagogical frameworks are used in hybrid teaching and learning? (2) How can we enhance students’ engagement in hybrid teaching and learning? (3) What is the impact of technological integration on hybrid learning scenarios, both for students and teachers? (4) How do training and support measures influence the willingness and ability of university teachers to implement hybrid teaching formats? (5) How do formative assessment and feedback methods in hybrid learning environments enable teachers to effectively monitor student progress and provide tailored support? (6) How does the implementation of hybrid learning affect student learning outcomes? This study identifies the following key themes: technological integration, pedagogical innovation, faculty support, student engagement, assessment practices, and learning outcomes. Our contribution of this literature review is related to teaching and learning by showing teachers the most appropriate way to avoid the challenges encountered when teaching in a hybrid way. These include strong technology integration, innovative pedagogical strategies, strong academic development and support, active student engagement, effective assessment practices, and positive learning outcomes.
- Capillary viscometry for routine measurements of newtonian liquidsPublication . Sequeira, Maria Carolina; Caetano, Fernando J. P.; Fareleira, João M. N. A.Viscosity is a thermophysical property of paramount importance, being essential for many scientific and industrial applications. The most common instruments for its measurement are glass capillary viscometers. Therefore, the use of capillary viscometers is widespread both in industry and in research. The range of viscosities of interest range from lower than that of water to several orders of magnitude higher values, the measurement of which requires different capillary viscometers. Most of the practical applications concern routine instruments, mainly for quality control. One main issue for the utilization of capillary viscometers relates to the need for their calibration, assuring its traceability to the water primary viscosity standard, to certify its worldwide validity. The present paper focuses on capillary instruments dedicated to perform viscosity measurements on Newtonian organic liquids at atmospheric pressure, as it is assumed that is the most widespread type of application for these viscometers. Capillary viscometry has a completely well-defined working equation, namely, the Hagen–Poiseuille equation. However, the practical performance of the measuring instruments deviates from that working equation. Most of those deviations are currently considered by many users. However, some of those deviations have not reached that status yet, like those concerning the effects due to the surface tension of the sample on the measurements. All these aspects are summarized and analyzed in the present article, together with a brief general description of the most common types of capillary viscometers, namely, the Ostwald and the constant-level or Ubbelohde instruments.