Browsing by Issue Date, starting with "2020-03"
Now showing 1 - 7 of 7
Results Per Page
Sort Options
- Norhierridin B, a New Hierridin B-Based Hydroquinone with Improved Antiproliferative ActivityPublication . Brandão, Pedro; Moreira, Joana; Almeida, Joana; Nazareth, Nair; Sampaio-Dias, Ivo E.; Vasconcelos, Vítor; Martins, Rosario; Leão, Pedro; Pinto, Madalena; Saraíva, Lucília; Cidade, HonorinaHierridin B (6), a methylated hydroquinone isolated from the marine picocyanobacterium Cyanobium sp. LEGE 06113, moderately inhibited the growth of colon adenocarcinoma HT-29 cells. Aiming to improve the potential antitumor activity of this natural product, the demethylated analogue, norhierridin B (10), as well as its structurally-related quinone (9), were synthesized and evaluated for their growth inhibitory effect on a panel of human tumor cell lines, including the triple-negative breast cancer (TNBC) cells MDA-MB-231, SKBR3, and MDA-MB-468. Norhierridin B (10) showed a potent growth inhibitory effect on all cancer cell lines. Moreover, the growth inhibitory effect of compound 10 on MDA-MB-231 cells was associated with cell cycle arrest and apoptosis. Norhierridin B (10) interfered with several p53 transcriptional targets, increasing p21, Bax, and MDM2, while decreasing Bcl-2 protein levels, which suggested the potential activation of a p53 pathway. Altogether, these results evidenced a great improvement of the antitumor activity of hydroquinone 10 when compared to 6 and its structurally-related quinone (9). Notably, hydroquinone 10 displayed a prominent growth inhibitory activity against TNBC cells, which are characterized by high therapeutic resistance.
- Clinical validation of a graphical method for radiation therapy plan quality assessmentPublication . Ventura, Tiago; Dias, Joana; Khouri, Leila; Netto, Eduardo; Soares, André; Costa Ferreira, Brigida; Rocha, Humberto; Lopes, Maria do CarmoBackground: This work aims at clinically validating a graphical tool developed for treatment plan assessment, named SPIDERplan, by comparing the plan choices based on its scoring with the radiation oncologists (RO) clinical preferences. Methods: SPIDERplan validation was performed for nasopharynx pathology in two steps. In the first step, three ROs from three Portuguese radiotherapy departments were asked to blindly evaluate and rank the dose distributions of twenty pairs of treatment plans. For plan ranking, the best plan from each pair was selected. For plan evaluation, the qualitative classification of ‘Good’, ‘Admissible with minor deviations’ and ‘Not Admissible’ were assigned to each plan. In the second step, SPIDERplan was applied to the same twenty patient cases. The tool was configured for two sets of structures groups: the local clinical set and the groups of structures suggested in international guidelines for nasopharynx cancer. Group weights, quantifying the importance of each group and incorporated in SPIDERplan, were defined according to RO clinical preferences and determined automatically by applying a mixed linear programming model for implicit elicitation of preferences. Intra- and inter-rater ROs plan selection and evaluation were assessed using Brennan-Prediger kappa coefficient. Results: Two-thirds of the plans were qualitatively evaluated by the ROs as ‘Good’. Concerning intra- and inter-rater variabilities of plan selection, fair agreements were obtained for most of the ROs. For plan evaluation, substantial agreements were verified in most cases. The choice of the best plan made by SPIDERplan was identical for all sets of groups and, in most cases, agreed with RO plan selection. Differences between RO choice and SPIDERplan analysis only occurred in cases for which the score differences between the plans was very low. A score difference threshold of 0.005 was defined as the value below which two plans are considered of equivalent quality. Conclusion: Generally, SPIDERplan response successfully reproduced the ROs plan selection. SPIDERplan assessment performance can represent clinical preferences based either on manual or automatic group weight assignment. For nasopharynx cases, SPIDERplan was robust in terms of the definitions of structure groups, being able to support different configurations without losing accuracy.
- Agricultural irrigation scheduling for a crop management system considering water and energy use optimizationPublication . Abrishambaf, Omid; Faria, Pedro; Gomes, Luis; Vale, ZitaCenter pivot systems are widely used to overcome the irrigation needs of agricultural fields. In this paper, an autonomous approach is proposed in order to improve the low efficiency of irrigation by developing a system based on the water requirement of the plantations, through field data. The data are local temperature, local wind, soil moisture, precipitation forecast, and soil evapotranspiration calculation. This information enables the system to calculate the real evapotranspiration for not being necessary to restrict to lysimetric measures. By this way, the system schedules the irrigation for the lower cost periods, considering the produced energy by the local resources, and the price of energy purchased from the utility grid. Also, it is considered that the irrigation must be carried out within the time interval in which the plantations do not reach the wilding point, so it will be carried out at the periods with the lowest cost. This will optimize the overall operational costs of the irrigation.
- Air conditioner consumption optimization in an office building considering user comfortPublication . Khorram Ghahfarrokhi, Mahsa; Faria, Pedro; Abrishambaf, Omid; Vale, ZitaThe rapid growth of energy consumption and its consequences in the last decades, made the world persuaded to energy optimization and energy management. Therefore, producers and prosumers should be equipped with the automation infrastructures to perform the management programs, such as demand response programs. Office buildings are considering as a proper case for implementing energy consumption minimization since they are responsible for a huge portion of total energy consumption in the world. This paper proposes a multi-period optimization algorithm implemented in Supervisory Control and Data Acquisition system of an office building. The developed optimization algorithm is an efficient solution considered for minimizing the power consumption of air conditioners by considering the user comfort constraints. Two determinative parameters are defined to prevent over-power reduction from certain devices. In order to respect to user preferences, priority numbers are dedicated to each air conditioner to present the importance of each device. A case study with several scenarios is implemented to verify the performance of the proposed algorithm in real life using real data of the building. The obtained results show the impacts of proposed parameters and different comfort constraints of algorithm while the main target of the optimization has been reached.
- Relatório para a obtenção do título de especialistaPublication . Barros, Susana Alexandra Pacheco Valente da SilvaO trabalho que em seguida se apresenta destina-se à obtenção do título de Especialista em Artes, conferido pelo Politécnico do Porto, no âmbito do Consórcio com o Politécnico de Coimbra. Esta opção deve ser explicada. Idealmente, o título deveria ser requerido na área das Humanidades, uma vez que a minha formação, experiência e perfil aí melhor se enquadram. Porém, a inexistência, nesta instituição, dessa área, como se pode comprovar pelo Diário da República, 2ª série, nº 200, Despacho nº 14093/2011, de 18 de outubro, retificado pelo Despacho P.Porto/P-011/2019, conduziu à escolha da única possível no elenco das áreas de formação ministradas no P.Porto, Área CNAEF 210 – Artes. Esta escolha alicerça-se ainda em dois outros critérios: por um lado, o âmbito da minha formação inicial, em História da Arte, e, por outro, no fato de exercer atividade docente neste Politécnico e aqui desejar concluir as minhas provas de Especialista; finalmente, porque as matérias sobre as quais se debruça este relatório têm, como se verá, uma ligação, senão direta, pelo menos profundamente contextual com a Arte, a Educação Artística e a sensibilização para o estudo, conhecimento e valorização do Património nas suas mais variadas vertentes. Como objetivos fundamentais pretendo demonstrar a adequação do meu percurso profissional à lecionação de diferentes Unidades Curriculares de cursos da Escola Superior de Educação do Politécnico do Porto, em particular das licenciaturas em Gestão do Património e Educação Básica. Acima de tudo, explicar como esse mesmo percurso profissional, nas suas múltiplas vertentes, constitui uma mais-valia para esta atividade docente, permitindo que os estudantes compreendam melhor a ligação com o lado prático e a dimensão laboral da Educação e do Património. O especialista conhece o mercado de trabalho e, como tal, a comunicação da sua experiência enriquece o perfil do estudante e possibilita-lhe um contacto com a realidade e a aquisição de experiências nas diferentes áreas e vertentes da gestão cultural e do património, bem como no âmbito da ação educativa em contextos não-formais. Se a primeira ideia está mais ligada à licenciatura em Gestão do Património, a segunda, como se percebe, relaciona-se intimamente com a de Educação Básica.[...]
- A gestão otimizada de recursos na economia social: desenho de um modelo colaborativo através de uma abordagem participativaPublication . Dias, Maria Catarina Cerqueira Gonçalves; Gomes, Paulo Veloso; Pimenta, Rui da Assunção EstevesA evolução da economia social em Portugal representa várias oportunidades de alcançar a resolução de problemáticas sociais, é um polo agregador de emprego remunerado e em simultâneo envolve os cidadãos em causas partilhadas e comuns. Por outro lado, este crescimento acarreta responsabilidades ao enfrentar, muitas vezes, entropias na sua sustentabilidade e financiamento. Desta forma pretende-se com esta dissertação abordar algumas das estratégias de gestão para contribuir para a sustentabilidade do setor, usufruindo das potencialidades da internet e da relevância das plataformas digitais de partilha, designadamente através da proposta de um modelo colaborativo de apoio à gestão, adequado às necessidades de eficiência do setor da economia social. Através de metodologias de gestão como o Whole of Government, aliado às vantagens digitais produzidas através de uma cultura participativa, os autores apresentados propõem um modelo de intervenção baseado na partilha e na participação como forma de alcançar resoluções para problemas comuns. Surge então o conceito da plataforma de serviços partilhados da economia social, como uma solução para a rentabilização de recursos comuns entre diversas organizações sociais, de forma a que as mesmas sejam fornecedoras e consumidoras, ligadas entre si. Assim, pretende-se atenuar as dificuldades de financiamento através da redução do desperdício e da duplicação de recursos, e valorizando a partilha e a interação digital, conduzindo a um aumento progressivo das receitas próprias. Com este estudo conclui-se que, a interação e a partilha são fundamentais para a manutenção da viabilidade económica do setor da economia social, e desta forma, devem ser implementadas todas as estratégias que possibilitem o estímulo à participação e à partilha entre as organizações que o compõem. A intervenção social é um dos pilares sobre os quais assenta a democracia e a organização cívica em Portugal, pelo que é relevante a reflexão sobre de que forma se podem solucionar problemas neste setor, visto que este é garantia da ordem e do bem-estar social da população.
- Numerical model to predict the effect of wood density in wood–steel–wood connections with and without passive protection under firePublication . Fonseca, Elza M M; Silva, Lino; Leite, Pedro ASThe main objective of this work is to present a numerical model to predict the effect of wood density in unprotected wood connections with an internal steel plate (wood–steel–wood), when comparing with the same connections using passive protection with gypsum plasterboard, submitted to fire conditions. Wood–steel–wood connections are made of four wood members, two on each side, with an internal steel plate that connects the pieces using steel dowel fasteners. First, analytical methodologies according to Eurocode 5 part 1-1 were used to design the connections at room temperature. After that, to predict the fire exposure and the connection ability, a numerical model was performed which permits to compare the fire resistance in wood–steel– wood connections without and with passive protection following the Eurocode 5 part 1-2. Results of the temperature and the wood char layer depth were compared using three different wood densities. The evolution of the charring rate was calculated in different locations of the connections and compared with the analytical value proposed by the Eurocode 5 part 1-2.