Browsing by Issue Date, starting with "2024-02-21"
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- Insect chitosan bioinspired approach for haemodialysis treatmentPublication . Martingo, Maria Lima; Borges, Sandra Cristina Ferreira; Silva, Sara Isabel Macedo Baptista da; Pintado, Maria Manuela EstevezChronic kidney disease (CKD) is characterised by a continuous decline in kidney function, often persisting for months or even years. The prevalence of CKD has been increasing over the years, representing a growing public health challenge and is expected to become the fifth leading cause of death by 2040. For patients with end-stage kidney disease (ESKD), renal replacement therapy (RRT), either through dialysis (haemodialysis, HD, and peritoneal dialysis, PD) or kidney transplantation, are crucial but expensive treatments. However, for some ESKD patients’ transplantation may not be appropriate due to medical contraindications, making dialysis the appropriate approach in these situations. In fact, both dialysis modalities, HD or PD, can offer similar long-term results. This thesis presents an innovative exploration into the extraction and application of insect chitosan (Tenebrio molitor) for biomedical purposes, specifically targeting HD. Initially, the potential of insect-derived chitosan as a sustainable and effective alternative to traditional sources (i.e. marine crustaceans) is demonstrated. Efficient extraction methods were developed (totalling between 6 h and 12 h), producing chitosan with physical and chemical properties comparable to commercial chitosan from crustaceans. Firstly, chitin was efficiently isolated from T. molitor through deproteinisation and demineralisation, with yields of approximately 5%. Subsequently, chitosan was obtained from the extracted chitin using an accelerated process, resulting in yields of between 65.0 ± 0.8% and 79.3 ± 0.8%. Characterisation using Fourier transform infrared spectroscopy (FTIR) confirmed structural similarities with commercial chitosan and degrees of deacetylation in the 73 - 75% range. The bioactive properties of chitosan obtained from T. molitor, including antimicrobial and antioxidant activities, were evaluated. All the microorganisms tested (Escherichia coli, Staphylococcus aureus, Candida albicans, Staphylococcus epidermidis and Pseudomonas aeruginosa) were inhibited, exhibiting minimum lethal concentrations between 2 and 8 mg/mL, confirming the antimicrobial activity of the extracted chitosan. In addition, chitosan showed antioxidant activity in the range of 60 to 65 µmol Trolox equivalent/g, suggesting its viability for various medical applications. This dissertation also developed a chitosan-based membrane (CH - M) specifically for HD purposes, culminating in a proof-of-concept phase for haemodialysis, focusing on the evaluation of diffusion and retention permeability parameters. The permeation characteristics of CH-M for urea and albumin were studied in vitro to assess their suitability as HD membranes. Urea was permeable to values of over 70 per cent and albumin was fully retained. This comprehensive approach ensured the exploration and development of an innovative, bio-inspired solution for HD, with an emphasis on sustainability and innovation, although further studies will have to be carried out on biocompatibility, treatment simulation duration, porosity, permeability and haemocompatibility tests.
- Emerging applications of Sterculia striata gum in medical, pharmaceutical, and environmental fields: prospects and challengesPublication . Freitas, Alessandra Ribeiro; Ribeiro, António José; Santos, Pauline Sousa dos; Oliveira, Thaísa Cardoso de; Oliveira, Jabson Herber Profiro de; Osajima, Josy A.; Ribeiro, Alessandra Braga; Veiga, Francisco; Bezerra, Roosevelt D.S.; Silva, Albert S.; Soares-Sobrinho, José Lamartine; Muniz, Edvani Curti; Silva-Filho, Edson C.Trees of the genus Sterculia produce acidic polysaccharides with high viscosity and the ability to form gels in water. This work emphasized the species Sterculia striata and the uses of its plant derivatives, such as seeds, fruits, stem bark, and exudates. The species showed prospects for industrial application (seeds with high protein content, fruits with antioxidant potential, and stem bark with anti-inflammatory, antinociceptive, and gastroprotective potential). From a physicochemical and rheological point of view, the exudate has a high molar mass value; it contains uronic acid, galactose, rhamnose, and xylose. Sterculia striata gum (SSG) is highly viscous in solution and can form thermoreversible gels where gelation conditions depend on the purification method, acetyl groups, and presence of salt. Due to the presence of carboxylic acid groups, polyanionic behaving SSG allow the formation of polyelectrolyte complexes, which have been used in drug delivery systems (DDS) to encapsulate drugs such as antimalarial drugs, improve essential oil stability and obtain films for antimicrobial purposes. This review contributes to the understanding of the use of this biomaterial, providing a basis for new research on its different applications and industrial use, with a focus on the pharmaceutical, medical, food, and environmental fields.
- O fenómeno Koreaboo na fandom transnacional da Hallyu : o caso de estudo da comunidade de fãs portugueses da cultura sul-coreanaPublication . Passeira, Sara Serapicos; Hernandez, Beatriz Puertas; Ganito, Tânia Cristina Frazão MoreiraEm todas as partes do mundo, os fãs da “Onda Coreana” utilizam a internet para ouvir KPop e ver K-Dramas, bem como para interagir com outros fãs que partilham estes interesses. Foi neste contexto que alguns membros desta comunidade começaram a ser denunciados pelos seus comportamentos obsessivos em relação à cultura sul-coreana e designados, à parte da maioria desta fandom, como koreaboos. A presente dissertação ambicionou identificar e analisar este fenómeno emergente, a partir do estudo de caso da comunidade portuguesa de fãs de entretenimento sul-coreano. Com o propósito de compreender as várias dimensões da fandom de hallyu e explorar o fenómeno koreaboo, foram combinadas metodologias de pendor quantitativo, através da construção e aplicação de um questionário, e qualitativas, destacando-se a análise de comentários de um blogue de fãs – Koreaboo Stories –, assim como a realização de uma entrevista semiestruturada a um grupo focal. Estes esforços resultaram na conclusão de que os comportamentos associados aos koreaboos dizem respeito à descontextualização de elementos culturais da Coreia do Sul, ações obsessivas perante celebridades sul-coreanas e a ignorância relativa a problemáticas sociais do país. Não obstante, a pesquisa revelou igualmente que os fãs detêm uma grande subjetividade acerca da identificação de koreaboos, que não torna os comportamentos assinalados como sinais claros deste fenómeno. Esta é uma dinâmica que vem estabelecer um reconhecimento mais detalhado dos koreaboos e que procura contribuir para o avanço do conhecimento científico no domínio dos Estudos Asiáticos, em articulação com os Estudos sobre Fãs e Estudos sobre a Hallyu.
- Women fleeing the war: access to sexual and reproductive healthcare in the EU under the temporary protection directivePublication . European Institute for Gender Equality; Costa, DiogoThis report presents the findings of a study launched following Russia’s war of aggression against Ukraine on 24 February 2022, which led to a displacement of an unprecedented scale and forced over 8 million people – mostly women and children – to flee Ukraine and seek refuge and protection across Europe (United Nations High Commissioner for Refugees (UNHCR) data, as of 9 May 2023). The overarching objective of this report is to assess the availability of specialised services available in the European Union for victims of conflict-related sexual violence (CRSV). More specifically, the report aims to identify gaps in the provision of sexual and reproductive health (SRH) services and offers recommendations to ensure that victims of CRSV enjoy immediate access to them. This three-phase study comprised desk research, an EU-wide questionnaire completed by 26 experts representing EU Member States and 12 follow-up interviews with representatives of relevant NGOs and public bodies conducted in four of the Member States: Czechia, Germany, Poland and Slovakia.
- More than a meat- or synthetic nitrogen fertiliser-substitute: a review of legume phytochemicals as drivers of ‘One Health’ via their influence on the functional diversity of soil- and gut-microbesPublication . Duarte, Rafael D. C.; Iannetta, Pietro P. M.; Gomes, Ana M.; Vasconcelos, Marta W.Legumes are essential to healthy agroecosystems, with a rich phytochemical content that impacts overall human and animal well-being and environmental sustainability. While these phytochemicals can have both positive and negative effects, legumes have traditionally been bred to produce genotypes with lower levels of certain plant phytochemicals, specifically those commonly termed as ‘antifeedants’ including phenolic compounds, saponins, alkaloids, tannins, and raffinose family oligosaccharides (RFOs). However, when incorporated into a balanced diet, such legume phytochemicals can offer health benefits for both humans and animals. They can positively influence the human gut microbiome by promoting the growth of beneficial bacteria, contributing to gut health, and demonstrating anti-inflammatory and antioxidant properties. Beyond their nutritional value, legume phytochemicals also play a vital role in soil health. The phytochemical containing residues from their shoots and roots usually remain in-field to positively affect soil nutrient status and microbiome diversity, so enhancing soil functions and benefiting performance and yield of following crops. This review explores the role of legume phytochemicals from a ‘one health’ perspective, examining their on soil- and gut-microbial ecology, bridging the gap between human nutrition and agroecological science.
- EPINEST, an agent-based model to simulate epidemic dynamics in large-scale poultry production and distribution networksPublication . Pinotti, Francesco; Lourenço, José; Gupta, Sunetra; Gupta, Suman Das; Henning, Joerg; Blake, Damer; Tomley, Fiona; Barnett, Tony; Pfeiffer, Dirk; Hoque, Md Ahasanul; Fournié, GuillaumeThe rapid intensification of poultry production raises important concerns about the associated risks of zoonotic infections. Here, we introduce EPINEST (EPIdemic NEtwork Simulation in poultry Transportation systems): an agent-based modelling framework designed to simulate pathogen transmission within realistic poultry production and distribution networks. We provide example applications to broiler production in Bangladesh, but the modular structure of the model allows for easy parameterization to suit specific countries and system configurations. Moreover, the framework enables the replication of a wide range of ecoepidemiological scenarios by incorporating diverse pathogen life-history traits, modes of transmission and interactions between multiple strains and/or pathogens. EPINEST was developed in the context of an interdisciplinary multi-centre study conducted in Bangladesh, India, Vietnam and Sri Lanka, and will facilitate the investigation of the spreading patterns of various health hazards such as avian influenza, Campylobacter, Salmonella and antimicrobial resistance in these countries. Furthermore, this modelling framework holds potential for broader application in veterinary epidemiology and One Health research, extending its relevance beyond poultry to encompass other livestock species and disease systems.
- Editorial notePublication . Rocha, Armando; Vicente, Marta
- Modelo de adaptação à carreira : um estudo com estudantes-atletas do 12º anoPublication . Gomes, Sara Filipa da Cunha Taveira; Oliveira, Íris MartinsO modelo de adaptação à carreira alude a formas como se gerem transições de carreira. Como a prática desportiva envolve diversos desafios, o modelo de adaptação à carreira pode ser útil para sustentar práticas em momentos de transição vivenciados pelos/as atletas. Com base neste modelo, o presente estudo pretende analisar se as competências emocionais e a adaptabilidade de carreira contribuem para explicar a certeza vocacional de estudantes-atletas que frequentam o 12.º ano, controlando os efeitos do sexo e do tempo de prática desportiva. Participaram 121 estudantes-atletas (Midade = 17.56, DP = .94) que responderam a um questionário de caracterização sociodemográfica, académica e desportiva, ao Questionário de Competência Emocional, à Escala de Adaptabilidade e à Escala de Certeza Vocacional. Resultados correlacionais sugerem relações positivas estatisticamente significativas entre as competências emocionais, a adaptabilidade de carreira e a certeza vocacional. Encontrou-se uma relação positiva estaticamente significativa entre a adaptabilidade de carreira e a frequência semanal da prática desportiva. Pela análise de variância multivariada, verificou-se que o sexo masculino apresenta médias superiores de competências emocionais e adaptabilidade de carreira do que o sexo feminino. Resultados da análise de regressão linear hierárquica indicam que as competências emocionais permitem, de forma estatisticamente significativa, explicar variações na certeza vocacional. Estudos futuros poderão investigar o papel dos pais e treinadores nos construtos estudados. Seria pertinente implementar práticas psicológicas com estudantes-atletas, agentes desportivos e educativos para apoiar os/as jovens no desenvolvimento de competências emocionais e adaptabilidade de carreira, na gestão da carreira dual e nas suas escolhas.