RUN
Repositório Institucional da Universidade NOVA de Lisboa
Entradas recentes
The need of a one health approach to tackle microbiological contamination in animal and dairy production
Publication . Viegas, Carla; Gouveia, Ana Filipa; Cervantes, Renata; Pena, Pedro; Carolino, Elisabete; Twarużek, Magdalena; Viegas, Susana; Laboratório Associado de Translacção e Inovação para a Saúde Global - LA Real (Pólo ENSP); Comprehensive Health Research Centre (CHRC) - Pólo ENSP; Centro de Investigação em Saúde Pública (CISP/PHRC); Escola Nacional de Saúde Pública (ENSP); Elsevier BV
With the global population rising, there is increasing demand for agricultural productivity, particularly for animal-derived proteins and products. This trend places additional pressure on natural resources and the workforce in the animal production sector. This study aims to address environmental and health factors influenced by animal production within the One Health framework, encompassing animal welfare, food security, food safety, worker´s health and climate change. In this context, three feedlots' farms and two dairies from the North of Portugal, representing the worst-case exposure scenario, were engaged in this study. Samples were collected using Electrostatic Dust Cloths (EDC) placed on farm surfaces and attached to work clothing (EDCT). Additional samples were obtained from feed, used bedding material, and surface swabs from feeders, drinkers, milking parlors, and frequently touched areas in social spaces (e.g., offices and changing rooms). Microbial characterization and azole-resistance screening were performed using diverse culture media, complemented by molecular assays (qPCR) targeting toxigenic fungal species. Thirty-eight mycotoxins were analyzed across the sampled matrices. This comprehensive approach identified critical sources of microbial and mycotoxin contamination: bedding material showed the highest bacterial contamination (TSA; 5.40 X 103 CFU.g-1), while swabs (MEA; 2.5 X 104 CFU.m-2 to 9.00 X 104 CFU.m-2) and feed (MEA; ranged from 1.33 X 102 CFU.g-1 to 8.00 X 102 CFU.g-1) exhibited the greatest fungal contamination. Feed was identified as the main source of mycotoxin exposure for both animals and workers, since all 16 feed samples tested positive for mycotoxin contamination. Results revealed widespread distribution of Aspergillus sp. across environmental matrices, highlighting the need for targeted interventions. Azole-resistance screening and mycotoxin profiling further emphasize the importance of implement targeted interventions to prevent, monitor, and remediate environmental contamination by fungi and mycotoxins across different contexts (food safety, animal health, public and occupational health) underscoring the value of a One Health approach.
Identity and labour market inequality: the role of public policy
Publication . Esteves, Mariana de Araújo Saraiva; Peralta, Susana
This thesis develops a unifying insight: public policies—whether neutral, universal, or targeted—operate in contexts of pre-existing inequalities and thus generate heterogeneous distributional effects. Using Portuguese administrative and survey data and quasiexperimental
methods, it provides causal evidence across three settings. Chapter 1 shows that a gender-neutral school-closure policy amplified gender gaps, reflecting underlying
norms. Chapter 2 finds that a universal education reform produced long-term and intergenerational spillovers for immigrants. Chapter 3 studies a gender quota on boards and shows that board diversity reshapes the workforce only when firm structure allows the signal to translate into action. Overall, the results highlight how policy design interacts with inequality to shape outcomes.
Replacing cereals with almond hulls in a 40% forage diet improves fatty acid composition of lamb fat and prevents the trans-10 shifted biohydrogenation pathways
Publication . Cachucho, L.; Alves, S. P.; Guerreiro, O.; Varregoso, M.; Costa, C.; Paulos, K.; Portugal, A. P.; Santos-Silva, J.; Dentinho, M. T. P.; Bessa, R. J.B.; Jerónimo, E.; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; Elsevier
Ruminant products contain fatty acids (FAs) with recognised benefits for human health, such as vaccenic (t11-18:1) and rumenic (c9,t11-18:2) acids, especially in animals fed forage-based diets due to the ruminal biohydrogenation of dietary polyunsaturated FAs. In contrast, high-cereal diets alter normal ruminal biohydrogenation pathways, favouring the production of t10-18:1 instead of t11-18:1 (termed as the t10-shift), resulting in a less favourable FA profile from a nutritional perspective. Replacing cereals with alternative resources rich in non-structural carbohydrates other than starch, such as almond hulls (AHs), which are characterised by high sugar content, in a diet containing a 40% forage diet, could be an effective approach to prevent t10-shift. However, there is limited information about the potential of replacing cereals with AHs to prevent the t10-shift and promote the formation and deposition of t11-18:1 and c9,t11-18:2 in lamb meat, as well as their effects on ruminal fermentation. Therefore, the effect of partially replacing cereals with increasing levels of AHs was evaluated in twenty-four lambs, distributed into three dietary treatments. In these treatments, cereals were progressively replaced with AHs, reaching 0, 9 and 18% of AHs in the diet composed of 40% dehydrated lucerne and supplemented with 5% soybean oil. The analyses of volatile fatty acid (VFA), FA, and dimethyl acetal (DMA) composition of the rumen content, and FA of Longissimus thoracis muscle were performed. Orthogonal polynomial contrasts were applied to evaluate the linear and quadratic effects of replacing dietary cereal with AHs. Replacing cereals with AHs up to levels of 18% did not substantially affect rumen activity, assessed by the lack of effect on rumen pH, VFA composition, or on the branched-chain FAs or DMAs from microbial origin. The most relevant effects of treatments were observed on C18 FAs. In rumen content, the proportions of t10-18:1 decreased linearly with increasing levels of AHs in diets, while t11-18:1 quadratically increased. Regarding the t10-shift, defined as the ratio of t10-18:1/t11-18:1 > 1, only two lambs in the 0AH diet had a ratio > 1, whereas all lambs fed AHs had a ratio < 1. In intramuscular fat, the proportions of t11-18:1 (+52.5%) and c9,t11-18:2 (+40.5%) increased with increasing levels of AHs in diets. No relevant differences were observed for n-6 or n-3 polyunsaturated FAs in lamb meat. Partially replacing cereals with AHs in a diet composed of 60:40 concentrate-to-forage prevented the occurrence of t10-shift and increased the health-beneficial C18 FAs, i.e. t11-18:1 and c9,t11-18:2.
Localized deformation and failure mechanism in TIG-welded wire-arc additively manufactured 304 stainless steel
Publication . Dong, Hang; Liu, Zhiyuan; Shen, Jiajia; Schell, Norbert; Li, Yongcun; Wang, Yong; Oliveira, João Pedro; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; Elsevier Editora Ltda
To enable the fabrication of complex structural components, this study investigates the post-weld microstructure and mechanical properties of wire arc additively manufactured (WAAMed) 304 stainless steel. The investigation employs both EBSD and in-situ synchrotron X-ray diffraction (SXRD) techniques. The research reveals grain size variations across the processed material (heat-affected zone (HAZ) vs fusion zone (FZ)), as well as differences in the kernel average misorientation (KAM) among the different regions that coexist in the material. During tensile deformation, the material underwent sequential martensitic transformation following the γ → ε → α′ sequence, with the FZ demonstrating greater elongation (approximately 64%). Strain accommodation is achieved through the synergistic interaction of dislocation slip and martensitic transformation. In-situ SXRD analysis reveals that during loading, the dislocation density increases to varying degrees across different regions (FZ, HAZ, and base metal (BM)), indicating the occurrence of coordinated deformation within the material. Ultimately, fracture occurs in the BM region under the combined effect of its high KAM value and the continuous increase in α′-martensite content under high local dislocation density.
Alginate scaffolds functionalised with zinc oxide nanostructures for osteochondral tissue regeneration
Publication . Silva, Hugo Afonso Pereira; Rovisco , Ana; Almeida , Henrique
The regeneration of osteochondral tissue remains a major challenge in tissue engineering because of the limited regenerative capacity of articular cartilage and the high mechanical demands of subchondral bone. Tissue engineering strives to develop strategies for this regeneration, often using natural polymers such as alginate. Nevertheless, these materials rarely combine the necessary mechanical properties with the biocompatibility and stability required to mimic bone tissue.
A promising strategy to overcome these limitations is the incorporation of nanomaterials. Among them, zinc oxide (ZnO) stands out for its biocompatibility, chemical stability, and its piezoelectricity, a property capable of generating local electrical stimulation under mechanical load, partially mimicking electromechanical phenomena in bone tissue.
In this work, alginate scaffolds were functionalised with ZnO nanostructures in three morphologies: nanowires, nanoplates, and nanoflowers. The incorporation of ZnO did not prove to be a differentiating factor in porosity or average pore size, as all groups, including pure alginate scaffolds, presented conditions favourable to nutrient diffusion and cell adhesion. However, in liquid media, the functionalised scaffolds exhibited greater robustness and a more gradual and controlled swelling profile compared to pure alginate scaffolds. This greater absorption capacity was inversely related to mechanical strength: the nanoplates, which exhibited the greatest swelling, also had the lowest modulus. Nanoflowers showed the best compromise between absorption and mechanical resistance, presenting a Young’s modulus of 4.44 ± 1.19 kPa, standing out from the other morphologies. Nevertheless, these values remain below those desirable for bone tissue applications, highlighting the need for optimisation to reinforce the mechanical performance without compromising the excellent absorption capacity and stability observed.
These results, accompanied by the high cell viability observed across the tested groups, provide a basis for future studies addressing strategies to reinforce mechanical performance, as well as the investigation of piezoelectric stimulation in osteochondral tissue engineering.