Escola Superior de Saúde
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Browsing Escola Superior de Saúde by Field of Science and Technology (FOS) "Ciências Naturais::Ciências Biológicas"
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- Humic acid aggregates with laccase and decreases the performance of the enzyme catalytic systems through various mechanismsPublication . Lopes, João; Marques-da-Silva, Dorinda; Peralta, Cláudia; Rodrigues, Joaquim Rui; Vaz, Daniela; Lagoa, RicardoLaccases are among the best-rated enzymes for industrial and environmental applications, yet their use in bioremediation is limited by interference from environmental components like humic acid (HA). This study evaluated HA impact on the oxidation of 2,2 ′-azino-bis-(3-ethylbenzothiazoline-6-sulphonate (ABTS) and two model pollutants — anthracene and methyl orange — by laccase( mediator) systems. HA consistently diminished conversion rates, with EC50 values between 5 and 51 mg/L suggesting diverse inhibitory mechanisms. We investigated potential mechanisms including substrate sequestration, radical quenching, and chelation of laccase coppers by HA. Incubations with free and immobilized HA showed that adsorption can impede anthracene degradation, at least at high concentrations, but not methyl orange. Using chemically generated ABTS radical and azide-blocked enzyme, it was demonstrated that HA scavenges free radicals produced by laccase, though this alone did not fully explain the observed interference with catalysis. Further assays with metal chelator and added copper or calcium ruled out HA binding to the laccase metal centers. Instead, data from molecular docking, f luorescence, light scattering, and microscopy revealed that HA forms micrometer-scale aggregates with laccase that encapsulate the enzyme. This newly identified mechanism likely applies broadly to laccase-based systems and must be considered in applications involving aqueous media containing humic substances.
- Level up! How Gamed-Based Activities Transform Learning and Alleviate Stress in Institutionalized ElderlyPublication . Lacomba-Arnau, Elena; Ribeiro, Anaísa; Sabino, Raquel; Pinheiro, Rafael; Lopes, Susana; Gaspar, Marisa; Navarro-Mateos, Carmen; Sousa, Micael; Rosa, MarleneMental health issues are a critical concern for the elderly, as the inability to manage stress during stimulation activities can significantly impair their ability to accept and effectively learn new tasks, thereby affecting their performance in daily life activities. Serious games are increasingly recognized as valuable in the context of rehabilitation; however, there is a paucity of studies examining how elderly individuals manage stress and learn in regular practice using such games. In this study, 10 institutionalized elderly participants underwent 6 game-based stimulation sessions playing the serious games Ta!Ti! and Mexerico. Learning variables, including time and error rates, were assessed at baseline (T0), mid-point (T1), and the final session (T2), along with stress management indicators, specifically cortisol levels, at T0 and T2. The findings revealed that learning profiles improved throughout the program, with more pronounced gains observed initially. Additionally, stress levels decreased following each game-based session. The study identified significant relationships between stress management and learning profiles, suggesting that game-based activities can effectively enhance both learning outcomes and stress reduction in the elderly.