FCT2-Artigos (em revistas ou actas indexadas)
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- Euphorbia resinifera: chemical composition and biological properties (short review)Publication . boutoub, Oumaima; Ghadraoui, Lahsen El; Miguel, Maria da GraçaThis review updates the information on the chemical composition of E. resinifera (spurge resin) latex and its biological properties, as well as those from the aerial parts and bee products (honey and propolis), generally without latex. From such review and according to the studies developed so far, it was possible to confirm that the chemical composition of latex and non-latex compounds differs. In the latex, diterpenes, nor sesquiterpenes, triterpenes, and serine proteases (EuRP-61) with 61 kDa predominate despite other minor compounds. The identified protease had anticoagulant, antiplatelet, and peripheral blood cell aggregation inhibitory properties. Phenolics, including flavonoids and tannins, have antioxidant activity and are dominant in the aerial parts of E. resinifera. Phenolic acids and flavonoids, particularly flavanones, flavones, and flavonols and their glycosides, were identified in the spurge resin honey. Generally, honey samples were within the acceptable limit of international standards. Antioxidant activity was reported for this monofloral honey. Antimicrobial activity was also detected in hydroalcoholic extracts of propolis.
- A critical analysis of the marina environmental risk assessment method applied to PortugalPublication . Neves, Maria C.; Cravo, Alexandra; Jacob, José; Correia, CátiaThe MERA (Marina Environmental Risk Assessment) procedure was applied for the first time along the coast of Portugal to classify the risk of 26 marinas on water quality. A risk ranking Atlas was produced to provide managers or decision-makers with spatial information that can help achieve sustainable development goals. The results indicate that the eight marinas in the south coast of the country (Algarve) face the highest risk, primarily due to pressures from navigation activities. However, the ranking generated along the Algarve using indicators of trophic status (TRIX and Eff. Coeff.) based on chemical analysis of in-situ water samples do not align with MERA. The MERA methodology, as it stands, presents significant limitations. Specifically, it does not account for water chemical parameters, sediment contamination, or temporal variability, all of which are crucial for accurate assessments. To enhance the robustness of MERA, this study suggests incorporating additional parameters and metrics that encompass broader environmental indicators.
- ZnO noparticles normalize pancreas function via the GLP-1 and oxidative stress pathways in diabetic ratsPublication . Mirzaei, Fatemeh; Jalili, Cyrus; Khodadadi, Iraj; Hosseini, Nashmin Fayazi; MAJDOUB, Nesrine; Naseri, Nima; Mirzaei, Amir; Abbasi, EbrahimThis experiment was carried out to investigate the effects of ZnO nanoparticles (ZnO NPs) on metabolic parameters, oxidative stress, apoptosis, and pathophysiological alterations of the pancreas in diabetic rats. Nanoparticle was synthesized and its characterizations were determined. We evaluate the toxicity and useful dosage of the ZnO NPs in Wistar male rats. Our experiment showed that 5 mg/kg had a useful effect and was not toxic. Hence, in the next step, the Wistar male rats were randomly divided into 3 groups as follows: (1) control rats (C); (2) diabetic rats (D), (3) diabetic rats received 5 mg/kg NP. After 4 weeks, animals were sacrificed, and blood chemical factors were measured. The oxidative stress, inflammatory, and apoptosis pathways were evaluated. Insulin and glucagon-like peptide-1 (GLP-1) mass was evaluated by immunofluorescence. The morphological changes were evaluated using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, hematoxylin and eosin (H&E), and aldehyde fuchsin. ZnO NP acts as an insulin sensitizer and normalizes blood glucose, GLP-1 levels as well as apoptosis, oxidative stress, and inflammatory pathway gene expression in diabetic rats. ZnO NP also alleviates the pathological alterations in the pancreas. This study showed that a low dose of ZnO NPs protects pancreatic β cells from oxidative stress and apoptosis. Administration of ZnO NP also normalized the pathophysiological alteration of the pancreas, thus normalizing metabolic abnormality.
- Multifaceted impact of exogenous salicylic acid on vicia faba l. under salt stress: plant growth, water status, and photosynthetic performance (OJIP Fluorescence)Publication . ANAYA, FATIMA; Fghire, R.; Wahbi, S.; Carvalho, Inês; Loutfi, K.Purpose This study investigated the effect of salt stress on growth, water status, and photosynthetic activity in faba bean plants and the role of salicylic acid (SA) in mitigating the harmful effects of salt stress. Methods Faba bean plants were subjected to different levels of salt stress (0, 90, 120, and 150 mM NaCl) and salicylic acid (0, 0.5, and 1 mM SA). Salt and SA treatments were applied starting from the seedling stage and continued for two months. Results Results show that salt stress significantly affects the different studied parameters. Salinity strongly decreases the plant weight (fresh and dry) and the plant water status (Leaf Water Potential (LWP), Stomatal conductance (gs), Relative water content (RWC). The analysis of the Photosystem II (PSII) function disruption indicates that salt stress induced an electron transport inhibition at the donor side of the PSII due to the Oxygen-Evolving Complex (OEC) inactivation (positive- K-band) and reduced the PSII unit’s energetic connectivity (positive-L-band). The evaluation of the rate reduction of the end electron acceptor at the Photosystem I (PSI) side revealed that salt stress resulted in gradual decreases in the reduction rates. Nevertheless, the exogenous application of salicylic acid (SA) allowed plants to maintain a high weight/length value with a significant improvement in plant water status. Chlorophyll-a fluorescence analysis shows that SA application improved at the donor side of electron transport (lower intensity of the K and L-band), with a larger pool size under the combination of 0.5 mM SA and high salt stress levels applications. Conclusion These results suggest that the salt stress significantly affects the PSII by the inactivation of the OEC and decreas¬ing the PSII unit’s connectivity. However, SA had a beneficial effect on the PSII and PSI salt stress tolerance in Vicia faba L.
- Testing the diversifying asset hypothesis between clean energy stock indices and oil pricePublication . Dias, Rui; Galvão, Rosa; Cruz, Sandra P.; Irfan, Mohammad; Alexandre, Paulo; Gonçalves, Sidalina; Teixeira, Nuno; Palma, Cristina; Almeida, LilianaIn theory, geopolitical risk and political uncertainty can directly affect energy markets. Fluctuations lead to the cost of clean energy sources as they compete with traditional energy. The purpose of this study is to analyse financial integration and test the diversifying asset hypothesis between clean energy indices, specifically the Clean Energy Fuels (CLNE), Nasdaq Clean Edge Green Energy (CELS), S&P Global Clean Energy (SPGTCLEN), TISDALE Clean Energy (TCEC.CN), Wilderhill (ECO) and West Texas Intermediate (WTI) stock indices, over the period from 1 January 2018 to 23 November 2023. Analysing the results reveals a scenario where most of the clean energy indices show cointegration with each other, indicating long-term relationships that reflect common trends in the clean energy sector. However, the relative independence of the WTI suggests that Oil still acts as an important and potentially diversifying external factor for investors focused on sustainable energy. Structural breaks in 2021 and 2022 in several indices point to significant events that have altered market dynamics, possibly including changes in environmental policies, technological innovations and the impacts of the COVID-19 pandemic. The cointegration evidence and structural breaks provide valuable information for building investment portfolios. Investors can consider the WTI to diversify portfolios dominated by clean energy assets, taking advantage of Oil’s relative independence. On the other hand, the high correlation between clean energy indices suggests that, within this sector, diversification options are more limited, requiring careful analysis of the specific characteristics of each index and the macroeconomic forces affecting them.
- Deep tutti-frutti II: explainability of CNN architectures for fruit dry matter predictionsPublication . Passos, DárioOne of the criticisms that deep chemometric models usually face is their lack of explainability. In this work, three different explainability methods (Regression Coefficients, LIME and SHAP) are applied to different convolutional neural network (CNN) architectures, previously optimized for the task of multifruit dry matter content prediction based on NIR spectra. Additionally, a convolutional filter characterization is also performed to help clarify the type of modelling performed by the convolutional layers. The analysis allowed to extract information about the wavelength bands relevant to the models’ performance (feature importance) and to understand how different convolutional layer topologies transform the spectra leading to three types of modelling: data driven preprocessing, dimensionality reduction and hierarchical feature extraction. Feature importance analysis indicates that the relevant spectral bands used by the different CNN architectures for prediction of dry matter is basically the same. They are the same as the bands relevant to PLS and these bands can be attributed to specific known vibrational groups. Moreover, in the context of the multifruit prediction task, the analysis also points out that CNNs tend to identify and use spectral features that are informative across different fruit spectra, much like domain-invariant features identified by di-CovSel variable selection.
- Effect of the synthesis parameters on the physicochemical properties of NaY Zeolite with faujasite structurePublication . Fernandes, Auguste; Plateau, Christiaan; Lourenço, João P.; Costa, Daniel; Esteves, Laura M.; Ferreira, Maria João; Nogueira, Isabel; Ribeiro, Maria FilipaNaY material belongs to the iconic family of zeolites with a Faujasite structure. These microporous aluminosilicate materials possess exceptional properties, making them essential in various applications, e.g., catalysis, gas sorption/separation, and ion exchange. In particular, NaY zeolite is a good model material for teaching fundamental concepts in crystallography, surface chemistry, and adsorption phenomena and a stimulating literature review topic for students. NaY zeolite can be easily synthesized by students at the laboratory scale. Its preparation and characterization offer valuable learning opportunities by linking theoretical knowledge with practical applications in Materials Science and/or Chemical Engineering courses. In this work, we propose a very simple but highly reproducible synthesis method for obtaining a highly crystalline NaY material. This flexible approach enables undergraduate students to investigate the influence of both the crystallization time and temperature on the outcome of NaY synthesis. By combining standard characterization techniques like powder X-ray diffraction, solid-state nuclear magnetic resonance, infrared spectroscopy, and scanning electron microscopy coupled with energy-dispersive spectroscopy, students acquire hands-on experience in Materials characterization, learn about the complementarity and limitations of the different characterization methods, and strengthen their knowledge in Inorganic Chemistry, Materials Science, and Analytical Chemistry.
- Consortium of microalgae/nitrogen-fixing bacteria as a next-generation biofertilizer, biostimulant and biopesticidePublication . Gouveia, Luisa; Ferreira, Alice; Bastos, Carolina Vela; Avetisova, Gayane; Karapetyan, Zhaneta; Toplaghaltsyan, Anna; Melkonyan, LusineThis study aims to provide insights into a new consortium of a microalga, twelve nitrogen-fixing (N-fixing) bacteria and a cyanobacterium. The microalga Tetradesmus obliquus (T), in conjunction with various N-fixing bacteria and the cyanobacterium Synechocystis sp. PCC 6803 (S), the N-fixing bacterium Sphingobacterium sp. L13G8 (5), cultivated in complete Bristol medium and in Bristol-NaNO3 free conditions, were examined. The study encompassed the analysis of their consortia, including evaluation of their growth, and potential as a biostimulant, biofertilizer and biopesticide, and assessed for sedimentation performance for targeted applications. The T and N-fixing bacteria consortia had higher growth in Bristol NaNO3-free media. The triple culture TS5 had the highest growth parameter (2.4 OD540) in the same medium, followed by T5. The consortia were employed to ascertain the efficacy of their biostimulants and biofertilizers on watercress (Lepidium sativum) and to determine the potency of their biopesticides against the fungal pathogens Fusarium oxysporum and Rhizoctonia solani (in certain consortia). Consortium T5 demonstrated the most significant impact on the seeds germination index (212.7%) and root length (6.0 cm) of L. sativum. The same consortium had a significant impact on the shoot length (4.4 cm) of L. sativum. Among all consortia that were examined, T5 exhibited significant inhibitory effects on the growth of F. oxysporum (60.6%) and R. solani (69.2%). In the same consortium, the rate of microalgal biomass sedimentation was enhanced by the N-fixing bacterium (0.4 cm h−1). Consortium T5 was the most effective in relation to growth and biomass sedimentation efficiency, in addition to its use as a biostimulant, biofertilizer and biopesticide. The created combination of microalga and N-fixing bacterium represents significant progress in the field of microalga cultivation, with notable benefits including improved biomass sedimentation and enhanced agricultural practices, as well as environmental friendliness and safety.
- Handling the heat: ocean acidification mitigates the effects of marine heatwaves on Posidonia oceanica seedlingsPublication . Pazzaglia, Jessica; Marín-Guirao, Lazaro; Ambrosino, Luca; Pes, Katia; Costa, Monya; Barrote, Isabel; Silva, João; Procaccini, Gabriele; Crysten Blaby-HaasOcean acidification and marine heatwaves are key drivers of marine ecosystem changes that can interact with one another and influence marine organisms. Seagrasses, including the long-lived Posidonia oceanica that is endemic to the Mediterranean Sea, are widely distributed along coastal habitats, forming highly valuable underwater meadows. The germination and survival of the early life stages of P. oceanica are strongly affected by environmental changes. To assess the impact of warming and acidification on its future, we conducted a multifactorial experiment in which P. oceanica seedlings were grown under ocean acidification conditions for 6 months and then exposed to a seawater warming event. Seedling performance was investigated by analysing photo-physiology, antioxidant capacity, energetic metabolism, and transcriptomic profiles. A weighted gene correlation network analysis was used to integrate phenotypic plant traits with transcriptomic results to identify central genes involved in plant responses to ocean acidification and temperature exposure. Results demonstrated that prolonged ocean acidification exposure enhances P. oceanica seedling resilience to marine heatwaves. Specifically, seedlings regulated their antioxidant systems and transcriptomic machinery to better cope with thermal stress. Under current CO2 concentrations, elevated temperatures induced stress in P. oceanica seedlings, impacting photosynthesis and respiration. However, ocean acidification could mitigate the impact of warming in the future, enhancing the resilience to global stressors of P. oceanica.
- The historical distribution and future expansion of paddy rice fields in Asian highlandsPublication . Song, Jing; Wang, Chunhui; Nunes, Luís; Liang, Zhongyao; Li, GangUrbanization and population growth are shrinking lowland rice areas, compelling exploration of Asia’s under studied highlands for future food security. Using earth observation data from 2000 to 2020 and machine learning method, we analyzed the distribution of paddy (irrigated) rice fields and their driving factors in Asian highlands (>1000 ma.s.l.). Highlands currently host 1.489 ± 0.176 millionha of rice, concentrated in the Tianshan–Tarim Basin, Hetao Plain along the Yellow River, and Yunnan–Guizhou Plateau. Altitude is the dominant constraint; additional precipitation is associated with reduced rice extent in the highlands, whereas population density and economic growth are associated with expansion. Our scenario modelling projects ~60% expansion and northward shift of high altitude paddies by 2035, yielding more nutrient rich, low contaminant grain and aiding saline–alkali reclamation. These findings highlight substantial, climate resilient capacity in Asian uplands to bolster sustainable rice supply and regional food security. This integrated assessment fills a critical knowledge gap regarding high elevation agroecosystems.