Browsing by Issue Date, starting with "2024-11-08"
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- Caracterização fitoquímica dos extratos de casca e raízes de Alchornea cordifoliaPublication . Lufuankenda, Nsinga; Rodilla, Jesus Miguel LopezA pesquisa de substâncias naturais de plantas resultou na descoberta de vários medicamentos úteis para o tratamento de diferentes doenças, impulsionando o desenvolvimento de tecnologias de extração e separação, métodos espectroscópicos para elucidação da estrutura e metodologias sintéticas fundamentais da Química orgânica analítica. Este trabalho teve como objetivo caracterizar os compostos fitoquímicos presentes nos extratos da casca e raízes de Alchornea cordifolia, pertencente à família Euphorbiaceae. Foram utilizadas técnicas de extração sólido-líquido com solventes de polaridade crescente (n-hexano, acetona e etanol) e o extrato de hexano foi submetido à desceração e a cera obtida foi primeiramente submetida ao processo de hidrólise com metanol em presença de NaOH obtendo a parte neutra e as partes ácidas (1 e 2) e depois as partes ácidas foram esterificadas com diazometano. A análise por Cromatografia Gasosa acoplada à Espectrometria de Massas (CG-EM) de cera do extrato de hexano da casca da parte aérea identificou quinze compostos fitoquímicos, incluindo triterpenoides, fitoesteróis e álcoois graxos. A caracterização por RMN dos extratos sugeriu a presença de substâncias bioativas, incluindo flavonoide, triterpenoide, ésteres, compostos fenólicos. Recomenda-se continuar o estudo com mais técnicas espectroscópicas (IV, CG-EM, HPLC) e investigações de actividades biológicas, como antimicrobiana e antidiabética.
- LinkedIn e sua utilidade como ferramenta de marca empregadora: Um comparativo entre empresas brasileiras e portuguesasPublication . Magalhães, Rayan Silva; Paço, Arminda Maria Finisterra doO presente trabalho analisa a utilização do LinkedIn como ferramenta de construção de reputação de marca empregadora para marcas brasileiras e portuguesas dos setores bancário e de telecomunicações. A construção de reputação contribui não só para a imagem das empresas, mas também para a atração e retenção dos melhores talentos disponíveis no mercado no atual cenário de globalização e redes sociais. Por meio pirâmide de avaliação de Relações Públicas de Jim McNamara e utilizando-se da metodologia de análise de conteúdo, o estudo busca avaliar, com base nas pesquisas bibliográficas, se as empresas contemplam os seguintes pontos em suas publicações: inputs, outputs, out takes e outcome. O objetivo de avaliar quais das empresas possuem as melhores estratégias de geração de valor e reputação foi alcançado com a ajuda de uma extensa revisão bibliográfica de autores das áreas de comunicação, recursos humanos e tecnologia. Conclui-se, que, atualmente, as redes sociais são fundamentais para que as empresas reforcem seus valores, principais benefícios e vantagens, diferenciando-se, assim, das demais e atraindo a atenção dos melhores candidatos.
- Propulsive Enhancement and Dynamic Stall Mitigation in Flapping AirfoilsPublication . Camacho, Emanuel António Rodrigues; Silva, André Resende Rodrigues da; Marques, Flávio DonizettiThe study of oscillating airfoils is the centerpiece for the biomimetization of flight, exploring newer energy-extracting devices, and improving rotor blade design. Typically, these are affected by highly nonlinear aerodynamic effects, which in most cases, still require substantial research regarding the aerodynamics and parameters that govern these systems. The present investigation looks into some of these topics by scrutinizing two primary fronts: the propulsive enhancement and the dynamic stall mitigation of flapping airfoils. After a comprehensive review of past investigations, the current work proposes a newer airfoil, the NACA0012-IK30 airfoil, that introduces the concept of dynamic curvature. This bioinspired concept is applied to the conventional NACA0012, producing an innovative geometry by dividing the airfoil into two parts, where we can deflect the leading edge independently from the rest of the airfoil. This newer design went through parametrical and optimal analysis by employing a diverse set of experimental and numerical methodologies, divided into two domains: lower Reynolds number, where the propulsive capabilities are studied, and higher Reynolds number, where dynamic stall mitigation is explored. At the lower spectrum of the Reynolds number, results show that the activation of the leading edge offered by the IK30 mechanism demonstrated the ability to improve considerably the propulsive power and efficiency. When comparing the proposed geometry with standard flapping, it is clear that the suggested design can provide optimal thrust with near-optimal propulsive efficiency, something unachievable in traditional flapping. Results obtained at the higher range of the Reynolds number, where the IK30 mechanism functions with dynamic stall mitigation purposes, show the adequacy of the proposed geometry under different plunging and pitching conditions. When correctly deflecting the leading edge, the aerodynamic stall experienced both in static and dynamic conditions can be mitigated or even eradicated, leading to significant drag reductions and modest lift enhancements. While the present study yielded encouraging results, the IK30 mechanism and the broad concept of dynamic curvature need to be the focus of further research. Using newer technologies, for instance, continuous camber morphing, coupled with ingenious kinematics, will allow us to explore newer pathways to extend our knowledge and exploit the aerodynamics of unsteady airfoils.
- Effect of Diosgenin in Suppressing Viability and Promoting Apoptosis of Human Prostate Cancer Cells: An Interplay with the G Protein-Coupled Oestrogen Receptor?Publication . Figueira, Marília I; Marques, Ricardo; Cardoso, Henrique J.; Fonseca, Lara R. S.; Duarte, Ana Paula; Silvestre, Samuel; Socorro, SílviaDiosgenin is a phytosteroid sapogenin with reported antitumoral activity. Despite the evidence indicating a lower incidence of prostate cancer (PCa) associated with a higher consumption of phytosteroids and the beneficial role of these compounds, only a few studies have investigated the effects of diosgenin in PCa, and its mechanisms of action remain to be disclosed. The present study investigated the effect of diosgenin in modulating PCa cell fate and glycolytic metabolism and explored its potential interplay with G protein-coupled oestrogen receptor (GPER). Non-neoplastic (PNT1A) and neoplastic (LNCaP, DU145, and PC3) human prostate cell lines were stimulated with diosgenin in the presence or absence of the GPER agonist G1 and upon GPER knockdown. Diosgenin decreased the cell viability, as indicated by the MTT assay results, which also demonstrated that castrate-resistant PCa cells were the most sensitive to treatment (PC3 > DU145 > LNCaP > PNT1A; IC50 values of 14.02, 23.21, 56.12, and 66.10 µM, respectively). Apoptosis was enhanced in diosgenin-treated cells, based on the increased caspase-3-like activity, underpinned by the altered expression of apoptosis regulators evaluated by Western blot analysis, which indicated the activation of the extrinsic pathway. Exposure to diosgenin also altered glucose metabolism. Overall, the effects of diosgenin were potentiated in the presence of G1. Moreover, diosgenin treatment augmented GPER expression, and the knockdown of the GPER gene suppressed the proapoptotic effects of diosgenin in PC3 cells. Our results support the antitumorigenic role of diosgenin and its interest in PCa therapy, alone or in combination with G1, mainly targeting the more aggressive stages of the disease.