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SARS-CoV-2 reinfection in a healthcare worker: First case in Portugal confirmed by viral genome sequencing

2026-04-16T15:45:13Z

Title: SARS-CoV-2 reinfection in a healthcare worker: First case in Portugal confirmed by viral genome sequencing Authors: Nunes-Silva, Cláudio; Pereira, Sara; Canelas, Gabriela; Pedro, Nicole; Fernandes, Paulo; Pereira, Luísa; Tavares, Margarida Abstract: Few reports of SARS-CoV-2 reinfection by antigenically similar variants are well documented. The interplay between natural acquired immunity, escape by emerging variants, and protective measures in the healthcare setting is considered in this description of the first phylogenetically confirmed SARS-CoV-2 reinfection in Portugal.

Agronomic and must quality performance of Vitis vinifera L. cv. ‘Loureiro’: a four-year study

2026-04-13T14:39:46Z

Title: Agronomic and must quality performance of Vitis vinifera L. cv. ‘Loureiro’: a four-year study Authors: Silva, Simão P.; Valín, M. Isabel; Mendes, Susana; Araújo-Paredes, Claúdio; Cancela, Javier J Abstract: Na região dos Vinhos Verdes, uma das castas mais cultivadas é a Vitis vinifera L. cv. ‘Loureiro’, produzida em condições de sequeiro. No entanto, a rega está a ser cada vez mais implementada para mitigar os efeitos das alterações climáticas. Neste sentido, no presente estudo foram avaliadas três diferentes estratégias de gestão da rega - sequeiro (R), rega deficitária (DI) e rega (I) - durante quatro ciclos culturais, entre 2019 e 2022. O principal objetivo foi avaliar a influência das estratégias de rega na produtividade agronómica e na qualidade do mosto. Para atingir este objetivo, foi avaliado um conjunto de parâmetros relacionados com o rendimento da videira e a qualidade do mosto. Além disso, foi medido o potencial hídrico do ramo (SWP) e estimada a transpiração da vinha e a sua evapotranspiração real. Os resultados mostraram uma clara sazonalidade na produção, com maior produtividade seguida de declínio, variando entre 19 766,5 kg/ha em R 2020 a 4 726,1 kg/ha em I 2021. O estudo demonstrou que a rega tem um efeito favorável a longo prazo na produtividade. Este fenómeno pode ser atribuído à constatação de que, embora apenas tenham sido detetadas disparidades numéricas entre os tratamentos nos anos iniciais, foram identificadas variações significativas (p<0,05) em 2022 entre as estratégias de rega. Além disso, a estratégia DI apresentou uma produtividade hídrica ótima, indicando uma elevada eficiência no uso da água durante todo o período do estudo. Estas descobertas sugerem que a rega de manutenção, mesmo nos casos em que é considerada deficitária, pode resultar numa maior produtividade hídrica a curto prazo e em taxas de produtividade elevadas a longo prazo.

Water potential, fluorescence, and photosynthetic parameters in Vitis vinifera ‘Alvarinho’ under different irrigation treatments

2026-04-13T14:37:15Z

Title: Water potential, fluorescence, and photosynthetic parameters in Vitis vinifera ‘Alvarinho’ under different irrigation treatments Authors: Mendes, S.; Portela, F.; Silva, S.; Araújo-Paredes, C.; Valin, I. Abstract: In temperate climates, water deficit conditions are necessary to produce high quality wine. However, excessive water deficit stress can lead to significant productivity and quality losses. Plant physiological responses to drought stress can be monitored through leaf water potential, photosynthesis, stomatal behaviour, and other parameters like fluorescence signals and indices obtained using a portable sensor (Multiplex®). This study aimed to evaluate stem water potential and leaf gas exchange parameters under increasing drought in field conditions and assess the feasibility of using chlorophyll fluorescence parameters to determine water status in vineyards. The research was conducted during grape maturation in 2022, under three irrigation treatments: full irrigation, deficit irrigation, and rainfed. Stem water potential (ψstem), stomatal conductance (gsw), net photosynthesis (AN), transpiration (E), leaf water use efficiency (WUEL), and Multiplex fluorescence signals were measured in the morning, midday, and afternoon to understand canopy physiology and its diurnal dynamics. Both deficit irrigation and rainfed conditions improved WUEL by reducing water usage, though validation with production quality data and rootstock effects on ‘Alvarinho’ drought tolerance is needed. The near-anysohydric nature of ‘Alvarinho’ supports moderate water deficits, but careful management is essential to avoid affecting photosynthesis. UV-induced chlorophyll fluorescence is a valuable, non-invasive tool for monitoring plant water status under stress.

Experimental and theoretical analysis of dopamine polymerization on the surface of cellulose nanocrystals and Its reinforcing properties in cellulose acetate films

2026-03-16T15:33:08Z

Title: Experimental and theoretical analysis of dopamine polymerization on the surface of cellulose nanocrystals and Its reinforcing properties in cellulose acetate films Authors: Souza, Amanda Lélis de; Oliveira, Arthur Vinicius de Abreu; Ribeiro, Laisse Dias; Moraes, Allan Robledo Fialho e; Jesus, Meirielly; Santos, Joana; Oliveira, Taila Velosa de; Soares, Nilda de Fátima Ferreira Abstract: The study of natural materials inspires sustainable innovations, with biomimetics excelling in surface modification. Polydopamine (PDA) offers a promising approach for modifying cellulose nanocrystals (CNC), enhancing their compatibility with hydrophobic polymers by improving interfacial adhesion. In this work, the modification of CNC with PDA (CNC@PDA) significantly enhanced the compatibility between the nanocargoes and the cellulose acetate (CA) matrix. The CNC@PDA complex formation was suggested through a combination of FTIR analysis, particle size distribution measurements and ζ-potential analysis. However, the exact mechanism behind dopamine polymerization on the surface of CNC remains a subject of ongoing debate among researchers due to its complexity. This study hypothesized the formation of modified CNC through this process. Furthermore, this study provided a satisfactory investigation of the antimicrobial activity of CNC@PDA in response to bacterial strains (E. coli, P. aeruginosa, S. aureus and L. plantarum) in view of the hypothesis of the possible generation of reactive oxygen species (ROS). Additionally, the incorporation of CNC@PDA CA films was analyzed to assess its effect as a mechanical reinforcement agent. The results showed an improvement in mechanical properties, with the 1% CNC@PDA film exhibiting the best balance between tensile strength and flexibility.