Biblioteca Digital do IPB
Repositório de Publicações do Instituto Politécnico de Bragança
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Effects of nitrogen fertilization on forage production, animal performance, and greenhouse gas emissions in tropical pastures: A systematic review
Publication . Silva, Hitalo Rodrigues da; Difante, Gelson dos Santos; Roberto, Francisca Fernanda da Silva; Ferreira Júnior, Marcos Antônio; Araújo, Carolina Marques Costa; Longhini, Vanessa Zirondi; Rodrigues, Jéssica Gomes; Pereira, Marislayne de Gusmão; Montagner, Denise Baptaglin; Ítavo, Luís Carlos Vinhas; Gurgel, Antônio Leandro Chaves; Castro, Marina
This systematic review aimed to synthesize evidence on the effects of nitrogen (N) fertilization on forage production, animal performance, and greenhouse gas emissions in tropical pastures. The research question was developed based on the PICOS strategy. A total of 84,629 documents were retrieved from six databases, of which 34 studies met the inclusion criteria due to their methodological robustness. Most studies were conducted under grazing conditions (69.7%), using Brachiaria brizantha (52.9%) and Panicum maximum (26.5%). Urea (53.2%) and ammonium nitrate (25.5%) were the most evaluated N sources, with application rates ranging from 0 to 1000 kg ha⁻¹ , often split into three applications. Nitrogen use increased stocking rate (157.7%), gain per area (189.4%), and average daily gain (31.0%) when application rates rose from 0 to 300 kg ha⁻¹ . Overall, N fertilization has potential to improve forage productivity and animal performance in tropical pastures; however, responses vary depending on rates, sources, and experimental conditions. Splitting N rates (20–60 kg ha⁻¹) and synchronizing applications with plant demand are effective strategies to reduce NH₃ and N₂O losses, enhance fertilizer use efficiency, and mitigate environmental impacts. Future research should focus on evaluating the effects of different N sources and doses on soil CO₂ and CH₄ emissions, enteric CH₄, and C/N dynamics within the soil–plant–animal system, as well as expanding studies to other forage and animal species representative of tropical grazing systems.
Timolol maleate-loaded double Pickering emulsion for the treatment of glaucoma: development, characterization, and ocular biocompatibility
Publication . Teixeira, Aniely dos Reis; Teixeira, Liandra Gracher; Schreiner, Tatiana B.; Santamaria-Echart, Arantzazu; Xavier, Viviane Flores; Silva, Gisele Rodrigues da; Barreiro, Filomena
Glaucoma is a leading cause of irreversible blindness, associated with high intraocular pressure. Topical beta-adrenergic antagonists, such as timolol maleate (TM), are first-line therapies but often have limited effectiveness due to rapid precorneal clearance and low ocular absorption. To address these limitations, a TM-loaded water-in-oil-in-water (W/O/W) double Pickering emulsion (TM-loaded DPE) was developed to enhance corneal retention, sustain drug release, and enhance ocular bioavailability. The TM-loaded DPE consisted of a primary W/O emulsion prepared from TM solution and mineral oil, stabilized by soy lecithin, combined with an external aqueous phase containing chitosan-Hydroxypropyl methylcellulose (chitosan-HPMC) particles as Pickering stabilizers, to form a W/O/W emulsion. Chitosan-HPMC particles had a size of 1.02 ± 0.16 μm, a zeta potential of 36.20 ± 2.41 mV, and a contact angle of 78.47 ± 1.80°, making them suitable Pickering stabilizers. The TM encapsulation efficiency in the TM-loaded DPE was 96%, indicating the high loading capacity of the developed system. Confocal laser scanning microscopy revealed a mononuclear droplet morphology, and the system exhibited excellent macroscopic physical stability under refrigerated conditions (4 °C, 12 months), as corroborated by the creaming index test, despite slight signs of coalescence observed in microscopic analysis. Rheological testing confirmed a non-Newtonian and shear-thinning behavior. The formulation achieved approximately 84% TM release over 48 h, indicating sustained release. The Hen egg test chorioallantoic membrane (HET-CAM) assay indicated no irritation potential, confirming its safety. Overall, these results highlight TM-loaded DPE as a promising drug delivery system for glaucoma treatment, offering improved drug retention and enhanced ocular bioavailability.
Caracterização e fabricação de filamento de PLA reforçado com fibras de linho
Publication . Junior, Delton Baragli; Ribeiro, J.E.; Rocha, João
A manufatura aditiva, especialmente a impressão 3D por modelagem por fusão e deposição (FDM), tem se consolidado como uma alternativa para a produção de peças complexas e customizáveis. No entanto, as limitações mecânicas dos polímeros convencionais utilizados na impressão 3D motivam a busca por novos materiais que combinem sustentabilidade e desempenho aprimorado. Neste contexto, este trabalho tem como objetivo a validação mecânica de um novo compósito desenvolvido para filamentos de impressão 3D, composto por poli (ácido lático) (PLA) reforçado com fibras naturais. A pesquisa foi conduzida por meio da fabricação de corpos de prova impressos em 3D e sua posterior caracterização mecânica por ensaios de tração e flexão. Foram analisadas as influências da incorporação das fibras naturais nas propriedades do material, considerando fatores como resistência mecânica e rigidez. No plano XY, o PLA+Linho apresentou aumento de +26,1% na resistência à tração em relação ao PLA comercial e de +49,2% em relação ao PLA virgem. Para flexão, no mesmo plano, observou-se aumento de +10,9% na resistência à flexão em comparação ao PLA comercial e de +77,6% em relação ao PLA virgem, além de incremento do módulo de elasticidade de +21,9% frente ao PLA comercial e de +125,3% frente ao PLA virgem. No plano XZ, verificou-se redução do desempenho do PLA+Linho em comparação aos demais materiais: a resistência à tração foi −47,8% inferior ao PLA comercial e −26,8% inferior ao PLA virgem; na flexão, a resistência foi −72,5% inferior ao PLA comercial e −67,5% inferior ao PLA virgem; e o módulo de elasticidade foi −59,6% inferior ao PLA comercial e −64,4% inferior ao PLA virgem. Os resultados evidenciam que o compósito PLA+Linho apresenta ganhos expressivos no plano XY e desempenho reduzido no plano XZ, reforçando a influência da orientação de impressão nas propriedades mecânicas.
Persistence of antioxidant, antimutagenic, and antigenotoxic properties of Polygonum maritimum L. extract after in vitro digestion supports its high potential as a functional food ingredient
Publication . Oliveira, Daniela; Hayrapetyan, Ruzanna; Dias, Maria Inês; Rodrigues, Maria João; Correa, Vanesa Gesser; Carvalho, António Paulo; Corre, Ludovic Le; Séverin, Isabelle; Peralta, Rosane Marina; Santos, Miguel Machado; Custódio, Luísa; Chagnon, Marie-Christine; Oliveira, Rui
Continuous exposure to xenobiotic-contaminated food causes adverse effects that may lead to health complications, including cancer. Halophytes are rich in polyphenols that exhibit notable biological properties and may contribute to cancer prevention. However, digestion can modify the chemical structure of polyphenols, potentially reducing their biological properties. This study investigated the protective effects of a polyphenol-rich extract from the halophyte Polygonum maritimum L. (PME) against contaminants-induced toxicity and assessed the persistence of these properties following in vitro digestion. LC-DAD-ESI/MSn analysis revealed that the phenolic composition of PME decreased considerably after digestion. Nevertheless, the antioxidant activity of PME, measured as a decrease in reactive oxygen species levels in H2O2-challenged HepG2 cells, persisted post-digestion. The extract showed enhanced anti-inflammatory activity after digestion, as shown by the ability to reduce (NO)-N-center dot production in lipopolysaccharide-stimulated RAW 264.7 cells. The antigenotoxicity of PME against the contaminant benzo[a]pyrene (BaP) in Caco-2 and HepG2 cells remained significant following upper gastrointestinal tract digestion (DPME), whereas the antigenotoxicity against H2O2 only persisted in Caco-2 cells. After colonic fermentation (FPME), antigenotoxicity was observed against H2O2 in HepG2 cells. PME also displayed antimutagenicity towards BaP in Salmonella typhimurium TA98 and TA100 strains, which remained relevant in DPME, but was drastically reduced in FPME. Furthermore, Danio rerio fed with PME and BaP showed reduced negative effects in terms of size and lipid peroxidation. These results suggest that PME can protect against contaminants-induced toxicity along the gastrointestinal tract, maintaining bioactivity until colonic fermentation. Thus, PME can be a promising functional food ingredient for health improvement.
Bioethanol fireplaces as indoor pollution sources: The role of burner design and fuel type
Publication . Vicente, Estela D.; Cipoli, Yago; Charres, Isabella; Nunes, Teresa; Cerqueira, Mário; Feliciano, Manuel; Galindo, Nuria; Yubero, Eduardo; Alves, Célia; Ryšavý, Jiří
Bioethanol fireplaces are marketed as clean and decorative heating alternatives. However, their impact on indoor air quality (IAQ) remains poorly characterised. This study investigates the indoor levels of gaseous and particulate pollutants using a bioethanol fireplace operated under realistic conditions. Two types of bioethanol fuels and two burner designs, a single-chambered (SC) and a double-chambered (DC), were tested under minimal ventilation. Concentrations of CO, NO, NO2, CO2, NH3, N2O, C2H6O, total volatile organic compounds (TVOCs), and carbonyl compounds were measured, while particulate matter (PM10) was characterised chemically and toxicologically. Combustion of both fuels led to substantial increases in indoor pollutant concentrations compared to background levels. Indoors, maximum average CO levels reached 5.67 & micro;g m-3, NO 0.33 & micro;g m-3, NO2 0.85 & micro;g m-3 and TVOCs exceeded 1400 & micro;g m-3. Acetaldehyde and formaldehyde were the dominant carbonyls, with the latter frequently surpassing the WHO guideline value along with NO2. Compared with traditional wood combustion, bioethanol combustion produced relatively higher indoor concentrations of nitrogen oxides, acetaldehyde, and formaldehyde. Average PM10 concentrations ranged from 31.5 to 173 & micro;g m-3, with higher indoor concentrations for the DC burner and Fuel 2. PM10 samples were enriched in bromine, ammonium and nitrate during combustion, and exhibited elevated oxidative potential. Differences in indoor pollutant levels and oxidative potential were observed depending on the burner design, fuel type and initial fuel load. These results demonstrate that flueless bioethanol fireplaces can markedly deteriorate IAQ, underscoring the need for performance standards, improved fuel formulations, and adequate ventilation to mitigate exposure risks associated with their use.