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- Analysis of integrated calcium looping alternatives in a cement plantPublication . Amorim, Ana; Filipe, Rui; Matos, Henrique A.Calcium looping is a promising post-combustion CO2 capturing technology, highly compatible with the cement industry, one of the major industrial sources of CO2 emissions. Limestone, a raw material for clinker, forms lime, a calcium looping adsorbent. Thus, it is possible to maximize the synergies between a cement plant and a calcium looping unit by establishing an integrated configuration. Nevertheless, the integration of calcium looping in cement plants has not yet been thoroughly studied. This study examines different integration alternatives, developing models for the preheater and calciner using Aspen Plus, validated with operational data, alongside an entrained-flow carbonator model considering adsorbent deactivation. By combining these models, six integrated configurations are proposed and compared with the tail-end calcium looping configuration. The integrated configurations show a reduction in fuel consumption and net energy consumption for the same CO2 avoided emissions. The most promising configuration was identified and a comparative techno-economic analysis was conducted.
- Assessment of influential operational parameters in the mitigation of CO2 emissions in a power plant: case study in PortugalPublication . Balanuta, Vítor; Baptista, Patricia; Neves da Fonseca Cardoso Carreira, Fernando Paulo; Duarte, Gonçalo; Casaca, Cláudia Sofia Séneca da LuzThe European decarbonization goals and requirement for energy independence are mostly relying on intermittent renewable energy sources for electrification. A numerical model was developed to simulate the operation of a steam generator, allowing a study of the potential impacts of retrofitting existing coal-fired power plants to operate with biomass or coal–biomass mixtures on combustion parameters and CO2 emissions. The results obtained using the operational parameters of the Sines power plant indicate that a mixture of 25% coal and 75% pine sawdust allow operation at λ = 1.8, demonstrating that a small amount of coal allows operation near the coal combustion parameters (λ = 1.9). These conditions have the drawback of a reduction of 8.7% in adiabatic flame temperature but a significant reduction of 57.5% in CO2 emissions, considering the biomass as carbon-neutral.
- Brands driving social change: the impact of social brand activism on consumers pro-social and pro-environmental attitudesPublication . Miguel, Alexandra; Miranda, SandraDespite its newness, brand activism is an increasingly studied field, given the consecutive adoption of this strategy by large international brands. However, the concrete impacts of brand activism actions, particularly in terms of promoting social change (for example, by promoting attitudes in favor of society and the environment on the part of company stakeholders, such as consumers), have not yet been categorically determined. Moreover, there is also still little research on the possible factors affecting this relationship, namely regarding the emotional processes that can mediate it. In this way, this article investigates the impact of social brand activism on consumers’ pro- social and pro-environmental attitudes, and the possible mediating effect of moral elevation, analyzing the brand activism of a Portuguese retail brand. The results showed that social brand activism can directly affect the pro-social and pro-environmental attitudes of consumers. Likewise, social brand activism has indirect impacts on the pro-social and pro-environmental attitudes of this group of stakeholders, through the mediating role of moral elevation. Thus, this study allows for a better understanding of the phenomenon of brand activism and the way this strategy can contribute to generating positive social and environmental changes.
- Chitosan nanoparticles for enhanced immune response and delivery of multi-epitope helicobacter pylori vaccines in a BALB/c mouse modelPublication . Amaral, Rita; Concha, Tomás ; Vítor, Jorge; Almeida, António J.; Calado, Cecília; Diogo Gonçalves, Lídia MariaHelicobacter pylori is the leading cause of chronic gastritis, peptic ulcer, gastric adenocarcinoma, and mucosal-associated lymphoma. Due to the emerging problems with antibiotic treatment against H. pylori in clinical practice, H. pylori vaccination has gained more interest. Oral immunization is considered a promising approach for preventing initial colonization of this bacterium in the gastrointestinal tract, establishing a first line of defense at gastric mucosal surfaces. Chitosan nanoparticles can be exploited effectively for oral vaccine delivery due to their stability, simplicity of target accessibility, and beneficial mucoadhesive and immunogenic properties. Methods: In this study, new multi-epitope pDNA- and recombinant protein-based vaccines incorporating multiple H. pylori antigens were produced and encapsulated in chitosan nanoparticles for oral and intramuscular administration. The induced immune response was assessed through the levels of antigen-specific IgGs, secreted mucosal SIgA, and cytokines (IL-2, IL-10, and IFN-γ) in immunized BALB/C mice. Results: Intramuscular administration of both pDNA and recombinant protein-based vaccines efficiently stimulated the production of specific IgG2a and IgG1, which was supported by cytokines levels. Oral immunizations with either pDNA or recombinant protein vaccines revealed high SIgA levels, suggesting effective gastric mucosal immunization, contrasting with intramuscular immunizations, which did not induce SIgA. Conclusions: These findings indicate that both pDNA and recombinant protein vaccines encapsulated into chitosan nanoparticles are promising candidates for eradicating H. pylori and mitigating associated gastric diseases in humans.
- Color evaluation of pre-shaded monolithic zirconia restorations on different substrates and resin cementsPublication . Fonseca, Vanessa; Neves, Cristina Bettencourt; Portugal, Jaime; Anes, Vitor; Chasqueira, Filipa; Roque, Joao CarlosThis study evaluated if the material, the substrate, and the cement have no influence on the color of pre-shaded monolithic zirconia crowns. The specific effect of the cement over each substrate/brand group was also studied. Two commercial brands of zirconia, Amann Girrbach (AG) and Zirkonzahn (ZZ), were used to produce crowns that were placed over three substrates (natural tooth, zirconia, metal) using two different resin cements (Ivoclar AG (Shaan, Liechtenstein) Neutral and Light) or glycerol (as the control) (n = 10). Lightness (L*), chroma (C*), hue (h*), and color difference (ΔE) of each crown were measured using a VITA Easyshade V® spectrophotometer (VITA Zahnfabrik, Bad Säckingen, Germany), following the standardized reference. Since normality was not verified by the Shapiro–Wilk test, data were statistically analyzed using the Kruskal–Wallis test for group comparisons and Tukey’s post-hoc test for multifactorial variance analysis (α = 0.05). ΔE medians ranged between 1.3 in the AG/zirconia substrate/glycerol group and 8.0 in the ZZ/metal substrate/light cement group. In general, lower values of ΔE were recorded in AG restorations compared to ZZ (p < 0.05), zirconia, and natural tooth substrates compared to metal (p < 0.001) and neutral compared to light cements (p < 0.05). Specifically, over the metal substrate, AG crowns with neutral cement and ZZ crowns with neutral cement and glycerol showed lower ΔE values (p < 0.05). Over the zirconia substrate, light cement presented higher ΔE values than glycerol in both brands but similar to neutral cement. Over the natural tooth, no significant differences were observed between cements (p > 0.05) in the AG brand, while in the ZZ group, light cement showed higher ΔE values (p < 0.05). The final color of the restorations was significantly influenced by the zirconia brand, substrate type, and resin cement. Light cement led to greater color variations, particularly in ZZ restorations. These findings highlight the importance of material selection in achieving esthetically pleasing zirconia restorations.
- Cytokine-based insights into bloodstream infections and bacterial gram typing in ICU COVID-19 patientsPublication . Araújo, Rúben Alexandre Dinis; Ramalhete, Luís; Von Rekowski, Cristiana; Henrique Fonseca, Tiago Alexandre; Calado, Cecília; Bento, LuísTimely and accurate identification of bloodstream infections (BSIs) in intensive care unit (ICU) patients remains a key challenge, particularly in COVID-19 settings, where immune dysregulation can obscure early clinical signs. Methods: Cytokine profiling was evaluated to discriminate between ICU patients with and without BSIs, and, among those with confirmed BSIs, to further stratify bacterial infections by Gram type. Serum samples from 45 ICU COVID-19 patients were analyzed using a 21-cytokine panel, with feature selection applied to identify candidate markers. Results: A machine learning workflow identified key features, achieving robust performance metrics with AUC values up to 0.97 for BSI classification and 0.98 for Gram typing. Conclusions: In contrast to traditional approaches that focus on individual cytokines or simple ratios, the present analysis employed programmatically generated ratios between pro-inflammatory and anti-inflammatory cytokines, refined through feature selection. Although further validation in larger and more diverse cohorts is warranted, these findings underscore the potential of advanced cytokine-based diagnostics to enhance precision medicine in infection management.
- Early mortality prediction in intensive care unit patients based on serum metabolomic fingerprintPublication . Araújo, Rúben Alexandre Dinis; Ramalhete, Luís; Von Rekowski, Cristiana; Henrique Fonseca, Tiago Alexandre; Bento, Luís; Calado, CecíliaPredicting mortality in intensive care units (ICUs) is essential for timely interventions and efficient resource use, especially during pandemics like COVID-19, where high mortality persisted even after the state of emergency ended. Current mortality prediction methods remain limited, especially for critically ill ICU patients, due to their dynamic metabolic changes and heterogeneous pathophysiological processes. This study evaluated how the serum metabolomic fingerprint, acquired through Fourier-Transform Infrared (FTIR) spectroscopy, could support mortality prediction models in COVID-19 ICU patients. A preliminary univariate analysis of serum FTIR spectra revealed significant spectral differences between 21 discharged and 23 deceased patients; however, the most significant spectral bands did not yield high-performing predictive models. By applying a Fast-Correlation-Based Filter (FCBF) for feature selection of the spectra, a set of spectral bands spanning a broader range of molecular functional groups was identified, which enabled Naïve Bayes models with AUCs of 0.79, 0.97, and 0.98 for the first 48 h of ICU admission, seven days prior, and the day of the outcome, respectively, which are, in turn, defined as either death or discharge from the ICU. These findings suggest FTIR spectroscopy as a rapid, economical, and minimally invasive diagnostic tool, but further validation is needed in larger, more diverse cohorts.
- Energy production from landfill gas: short-term managementPublication . Domingues, Nuno SoaresAn increasing lack of raw materials, resource depletion, environmental impacts and other concerns have changed the way the population faces garbage disposal and municipalities implement waste management strategies. The aggravated global rise in municipal solid waste (MSW) generation has led to a new stage in full development, with objectives and targets set by the European Union regarding reducing the production of MSW. The targets also include the increasing selective collection, reuse, recycling and recovery (organic and energetic) of the waste produced. At the same time, the European Union has also set caps for the greenhouse gas emissions and for increasing the use of alternative renewable energy sources. In this context, one of the sources of renewable energy that is beginning to be used to produce electricity in our country is biogas. Finally, AD promotes the development of a circular economy. The present study introduces the formalism for a computer application that simulates the technical-economic behaviour of the short-term management of biogas for the conversion of electricity, and the mathematical model is formulated as a mathematical programming problem with constraints. A simulation for a case study of short-term management is given using the real landfill data available. The case study proves the ability of the LandGEM, despite some authors' support that the Tabasaran-Rettenberger model provided a more reliable estimate, especially when compared to actual landfill data. The present paper is a contribution to the optimisation of the management of electricity from the use of biogas, namely the second phase of the Strategic Plan for Urban Waste. In addition to complying with the legislation in force, the use of biogas to produce electricity is an added value for the concessionaires of waste treatment and final destination units, as this alternative energy source can provide not only self-sufficiency in electricity for these units but also the export of surplus energy to the National Electricity Grid, thus contributing to the self-sustaining management and energy flexibility that is intended for these infrastructures.
- Highly porous NiFe nanofoams synthesized by dynamic hydrogen bubble template for hydrogen evolution in alkaline mediaPublication . Carvalho, Gabriel Garcia; do Nascimento, Ricardo Espingardas; Morais Silva, Teresa; Montemor, Maria de FátimaWhen coupled with renewable energy sources, alkaline electrolysis (AEL) is a clean technology to produce hydrogen. The conventional electrodes that have been established as the commercial standard for AEL are perforated nickel plates, which have low surface area and high mass loads of active material. The use of Ni has been associated with the adsorption of protons and their recombination into H2 molecules, assisting and enabling the hydrogen evolution reactions. Due to the rising Ni price, there is a demand for less expensive electrode materials with identical, or better, performance. Thus, this work explores new alternative electrode materials and combines Ni with a cheaper and also electroactive metal, iron. For this purpose, highly porous bimetallic nanofoams are produced through the dynamic hydrogen bubble template. NiFe electrodes of different compositions are characterized by scanning electron microscopy, energy-dispersive spectroscopy, linear sweep voltammetry, and chronopotentiometry analysis. The results allow obtaining key parameters that are essential for the optimization of the electrode's response considering overpotentials, Tafel slopes, and other electrochemically relevant parameters.
- Impact of neutrophil-activating protein conservation on diagnostic tests and vaccine designPublication . Diogo Gonçalves, Lídia Maria; Almeida, António J.; Calado, CecíliaBACKGROUND: The neutrophil activating protein (NAP) is a highly immunogenic and virulence factor of Helicobacter pylori, presenting inflammatory and immunomodulatory activity. Consequently, NAP has been explored as a diagnostic and therapeutic target. However, when evaluating a target protein to design diagnostic methods or vaccines, it is critical to determine the protein conservation among the bacterial population, as well the impact of alterations of amino acid residues on the protein antigenic profile. RESULTS: In the present work, NAP conservation and theoretical antigenicity were determined among 51 sequences from H. pylori isolated from patients worldwide. A high NAP conservation (83%) was observed, where 17 amino acid residues, among the 144 residues of the protein, were polymorphic. Alterations at these polymorphic sites had a theoretically low impact on predicted antigenicity, where only 5 NAPs out of 51 NAPs presented a slightly different antigenic profile in relation to the consensus sequence. According to that, it was possible to recognize in western blotting 93% of NAP from different bacteria (n = 15) using polyclonal antibodies developed against a specific NAP. CONCLUSIONS: It was predicted that when working with polyclonal antibodies or large NAP fragments for diagnostic and vaccine design, slight variation in protein sequence will have a minimal impact on NAP recognition. However, if a NAP monoclonal antibody or small NAP epitopes are considered, it is critical to select the most conserved and antigenic NAP regions, to maximize the coverage of NAP variants.