Browsing by Issue Date, starting with "2025-04-24"
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- Injectable and implantable hydrogels for localized delivery of drugs and nanomaterials for cancer chemotherapy: A reviewPublication . Pouso, Manuel António do Rosário ; Melo, Bruna Daniela Lopes ; Gonçalves, Joaquim; Louro, Ricardo; Mendonça, António; Correia, Ilídio Joaquim Sobreira ; de Melo-Diogo, DuarteMultiple chemotherapeutic strategies have been developed to tackle the complexity of cancer. Still, the outcome of chemotherapeutic regimens remains impaired by the drugs’ weak solubility, unspecific biodistribution and poor tumor accumulation after systemic administration. Such constraints triggered the development of nanomaterials to encapsulate and deliver anticancer drugs. In fact, the loading of drugs into nanoparticles can overcome most of the solubility concerns. However, the ability of systemically administered drug-loaded nanomaterials to reach the tumor site has been vastly overestimated, limiting their clinical translation. The drugs’ and drug-loaded nanomaterials’ systemic administration issues have propelled the development of hydrogels capable of performing their direct/local delivery into the tumor site. The use of these macroscale systems to mediate a tumor-confined delivery of the drugs/drugs-loaded nanomaterials grants an improved therapeutic efficacy and, simultaneously, a reduction of the side effects. The manufacture of these hydrogels requires the careful selection and tailoring of specific polymers/materials as well as the choice of appropriate physical and/or chemical crosslinking interactions. Depending on their administration route and assembling process, these matrices can be classified as injectable in situ forming hydrogels, injectable shear-thinning/selfhealing hydrogels, and implantable hydrogels, each type bringing a plethora of advantages for the intended biomedical application. This review provides the reader with an insight into the application of injectable and implantable hydrogels for performing the tumor-confined delivery of drugs and drug-loaded nanomaterials.
- Estudo de desenvolvimento de um algoritmo de determinação de fiabilidade da aeronave em fase de projeto na lógica da falha catastróficaPublication . Real, Diego Gabriel Rodriguez Corte; Saúde, José Manuel Mota Lourenço daNum setor onde a segurança é a principal prioridade, a fiabilidade e a manutenção desempenham um papel essencial na prevenção de acidentes, garantindo a integridade dos sistemas e otimizando os processos de manufatura. A consideração destes fatores não só contribui para a minimização dos custos ao longo do ciclo de vida da aeronave, como também prolonga a sua vida útil, resultando numa operação mais eficiente e numa maior satisfação dos operadores e utilizadores. Com a evolução constante da indústria aeronáutica, a necessidade de aumentar a disponibilidade das aeronaves e reduzir os custos operacionais tem impulsionado a adoção de programas de fiabilidade, que se têm revelado ferramentas fundamentais para a gestão e otimização da manutenção. Neste contexto, esta dissertação propõe e avalia a viabilidade da implementação de um programa de determinação de fiabilidade para a aeronave LUS222, atualmente em desenvolvimento em parceria com o CEiiA, no enquadramento dado pela probabilidade de falha catastrófica.
- CFD Analysis of Alcohol-to-Jet Fuel Combustion in a CFM56-3 CombustorPublication . Fernandes, Rafael Valente; Brojo, Francisco Miguel Ribeiro ProençaThe aviation industry’s heavy reliance on fossil fuels significantly contributes to polluting emissions, exacerbating global warming and degrading air quality, prompting the urgent need for sustainable alternatives. One promising solution is the use of Sustainable Aviation Fuels (SAFs), which offer a viable alternative to conventional jet fuel. Among them, Alcohol-to-Jet Synthetic Paraffinic Kerosene (ATJ-SPK), a bio-derived fuel, has shown potential to reduce aviation’s environmental impact. This study presents a Computational Fluid Dynamics (CFD) analysis of ATJ-SPK combustion in a CFM56-3 combustor using ANSYS Fluent, employing the Reynolds Stress Model (RSM) as the viscous model. The research focuses on comparing the emissions of ATJ-SPK with those of conventional Jet A fuel while assessing ATJ-SPK’s viability as a drop-in replacement. The analysis was conducted across the power settings of the ICAO Landing and Take-Off (LTO) cycle, evaluating key combustion characteristics such as temperature distribution, emissions, and efficiency. Results indicate that ATJ-SPK exhibits similar combustion behaviour to Jet A, demonstrating its potential as a sustainable alternative fuel. Notably, NOx emissions show a reduction across all power settings, particularly at full power, suggesting environmental benefits. CO emissions, however, require further validation due to inconclusive trends. Importantly, the simulation results align well with experimental data, particularly in key parameters like outlet temperature, reinforcing the reliability of the CFD approach. These findings support the feasibility of ATJ-SPK as a viable replacement for conventional jet fuel, contributing to aviation’s transition toward sustainability.