155 research outputs found

    Cytocompatibility and response of osteoblastic-like cells to starch-based polymers : effect of several additives and processing conditions

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    This work reports on the biocompatibility evaluation of new biodegradable starch-based polymers that are under consideration for use in orthopaedic temporary applications and as tissue engineering scaffolds. It has been shown in previous works that by using these polymers it is both possible to produce polymer/hydroxyapatite (HA) composites (with or without the use of coupling agents) with mechanical properties matching those of the human bone, and to obtain 3D structures generated by solid blowing agents, that are suitable for tissue engineering applications. This study was focused on establishing the influence of several additives (ceramic fillers, blowing agents and coupling agents) and processing methods/conditions on the biocompatibility of the materials described above. The cytotoxicity of the materials was evaluated using cell culture methods, according to ISO/EN 109935 guidelines. A cell suspension of human osteosarcoma cells (HOS) was also seeded on a blend of corn starch with ethylene vinyl alcohol (SEVA-C) and on SEVA-C/HA composites, in order to have a preliminary indication on cell adhesion and proliferation on the materials surface. In general, the obtained results show that all the different materials based on SEVA-C, (which are being investigated for use in several biomedical applications), as well as all the additives (including the novel coupling agents) and different processing methods required to obtain the different properties/products, can be used without inducing a cytotoxic behaviour to the developed biomaterial

    Exploiting the bioactive properties of γ-oryzanol from bran of different exotic rice varieties

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    The rice industry is one of the most significant food industries since rice is a widely consumed cereal in the world. As a result of this substantial production, the rice industry has a significant amount of side streams, including bran, representing millions of tons of raw materials mainly designated to animal feed. Rice bran is a rich source of γ-oryzanol, a bioactive compound with substantial health benefits. In this perspective, different bran rice samples from distinct germplasm origins (Philippines, Italy and Portugal) were studied for their γ-oryzanol content by HPLC-PDA, cytotoxicity in four human tumour cell lines, hepatotoxicity in a normal cell line and for their antimicrobial effects on different bacterial and fungal strains. The Ballatinao sample presented the strongest activity against all the tumour cell lines, and was also the sample showing the highest amount of γ-oryzanol, suggesting its contribution to the exhibited cytotoxic properties. Regarding the antimicrobial activity, the tested samples were able to inhibit the majority of bacterial and fungal strains, with the Portuguese Ceres sample being the one presenting the highest bacterial inhibition and the Maluit and Dinorado samples, the highest fungal inhibition. Overall, the results show that rice bran extracts may be considered as potential candidates for antimicrobial agents when incorporated into food matrices.Ruaraid Hamilton from IRRI Philipines for supplying the rice seeds and Paula Marques from COTARROZ Portugal for multiplying the rice grain collection in COTARROZ greenhouses. Project POCI-01-0247-FEDER-017931 - ArrozBig - Development of rice products with low glycemic index and FCT SFRH/BD/120929/2016 PhD grant (Ana Castanho). The authors are grateful to the Foundation for Science and Technology (FCT. Portugal) and FEDER under Program PT2020 for financial support to CIMO (UID/AGR/00690/2013) and R. Calhelha contracts.info:eu-repo/semantics/publishedVersio

    A penalty scheme for the Tchebycheff scalarization method to optimize the single screw extrusion

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    The polymer single screw extruder optimal design has been involving the optimization of six objectives. Multi-objective optimization methods, in particular those based on the weighted Tchebycheff Scalarization (wTS) function, have provided reasonable solutions in a way that good trade-offs between conflicting objectives are identified. In this work, a new penalty term is added to the wTS function aiming to guide the solution toward the Pareto front. The corresponding formulation works similarly to the penalty-based boundary intersection function. The goal of the proposed penalty parameter scheme is to balance convergence and diversity. Since six objectives are simultaneously optimized, the penalty scheme provides large as well as small penalty parameter values to enlarge the improving region. The results show that the set of solutions obtained by the penalty-based wTS algorithm can reasonably well cover the Pareto front.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie SkłodowskaCurie grant agreement No. 734205 – H2020-MSCA-RISE-2016

    Multi-objective polymer single screw extruder optimization

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    The optimal design of a polymer single screw extruder may involve various conflicting performance objectives and depends on operating and geometrical parameters. In this work, five bi-objective problems are analysed where one of the most relevant performance objectives, the mass output, is considered in all problems. For simplicity purposes, only the operating parameters are optimized being the geometrical parameters assumed to be fixed. The optimal solution set of each problem is compared with the corresponding two-dimensional projection of the Pareto front obtained when the six objectives are optimized simultaneously. A weighted Tchebycheff scalarization algorithm is implemented based on the simulated annealing method to obtain the Pareto front of the multi-objective optimisation problems.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie SkłodowskaCurie grant agreement No. 734205 – H2020-MSCA-RISE-2016

    ENERWAT project: some preliminary results

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    Water and energy are two linked important resources and its use efficient must be profoundly studied. On the other hand, it is believed that there are significant differences between the pattern of water and energy consumption in rural and urban areas, whose influencing factors require study too. Swveral research state a large difference in urban and rural household water consumption pattern. However, rural household's consumptions are under-researched compared to urban residential consumptions. This paper aims to provide some preliminary results of a research project named ENERWAT, supported by the Portuguese Science and Technology Fiundation. One of the parts of the referred project was the design, application and results analysis of a survey, in order to find the main differences in the water and energy consumptions at the end-use level, and tha factores that influence it in urban and rural households. A total of 245 households participated in the research during the year of 2016 (urban: 110 dwellings) and (rural: 135 dwellings), responding to questions such as their family composition, dwellings characterization, water and energy consumption habits and conservation behaviors of these resources. Some of the obtained results will be here provided.This work was partially funded by project POCI-0-0145-FEDER-016730 (PTDC/AAG-REC/4700/2014) under the name ENERWAT: Water for energy: characterization, modeling and measures for reducing domestic urban and rural consumption, funded by the Foundation for Science and Technology and co-financed by the European Regional Development Fund (ERDF) through COMPETE 2020 - Operational Competitiveness and Internationalization Program (POCI). This work was partially supported by the FCT (Portuguese Foundation for Science and Technology) through the project PEst-OE/ECI/UI4082/2013 (C-MADE)

    Contributo para o conhecimento da biodiversidade marinha da ilha das Flores

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    XIII Expedição Científica do Departamento de Biologia - Flores e Corvo 2007.No âmbito da XIII Expedição Científica Flores e Corvo/2007, organizada pelo Departamento de Biologia da Universidade dos Açores, efectuaram-se várias observações e recolhas de organismos marinhos, utilizando 3 metodologias: mergulho (bentos), arrasto (plâncton) e prospecção no intertidal

    Actividades de educação ambiental realizadas pelo CCPA no decorrer da XIII Expedição Científica do Departamento de Biologia – Flores e Corvo 2007

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    XIII Expedição Científica do Departamento de Biologia - Flores e Corvo 2007.Tendo em conta a crescente importância da educação ambiental para a construção da cidadania, força motriz de um desenvolvimento sustentável, o Centro de Conservação e Protecção do Ambiente (CCPA) promoveu a realização de diversas actividades de cariz teórico-prático sobre questões ambientais e de valorização do património biológico, junto dos utentes da Ecoteca das Flores e dos alunos da Escola Básica Integrada das Colmeias e da Escola EB 2.3/S de Melgaço, que participaram na XIII Expedição Científica do Departamento de Biologia às ilhas das Flores e Corvo

    Polymer single screw extruder optimization using tchebycheff scalarization method and simulated annealing algorithm

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    The single screw extrusion optimal design involves the optimization of six criteria that can be efficiently handled by a weighted Tchebycheff scalarization method. The performance of the method has been analyzed for three different methods to generate weight vectors. The experimental results show that the tested strategies provide similar and reasonable solutions and supply a valuable procedure to identify good trade-offs between conflicting objectives.European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 734205- H2020-MSCA-RISE-2017. The work has also been supported by FCT – Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020, UIDB/00013/2020 and UIDP/00013/2020 of CMAT-U

    Single screw extrusion optimization using the tchebycheff scalarization method

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    The optimal design of a single screw extrusion (SSE) is a very difficult task since it deals with several conflicting performance indices. Past research to find the optimal SSE design has been successfully conducted by optimization procedures, in particular by multi-objective optimization. Problems with two or more objectives have been addressed by multi-objective evolutionary algorithms that search for the whole set of promising solutions in a single run. Our approach has been guided by the bi-objective optimization problems, using a methodology based on the weighted Tchebycheff scalarization function. The numerical results show that the proposed methodology is able to produce satisfactory results with physical meaning.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020, UIDB/05256/2020 and UIDP/05256/2020, UIDB/00013/2020 and UIDP/00013/2020 of CMAT-UM, and the European project MSCA-RISE-2015, NEWEX, Reference 734205

    Inhibition of bladder tumor growth by chitooligosaccharides in an experimental carcinogenesis model

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    Urinary bladder cancer is one of the most common cancers worldwide, with the highest incidence in industrialized countries. Patients with cancer commonly use unconventional and complementary therapy including nutraceuticals. In this study we evaluated the efficacy of chitooligosaccharides (in orange juice) in rat bladder cancer chemoprevention and as therapeutic agent, on a rat model of urinary bladder carcinogenesis induced with N-butyl-N-(4-hydroxybutyl) nitrosamine. Results indicate that chitooligosaccharides may have a preventive effect on bladder cancer development and a curative effect upon established bladder tumors, dependent on the concentration ingested 500 mg/kg b.w., every three days, showed capacity to inhibit and prevent the proliferation of bladder cancer; however, this was associated with secondary effects such as hypercholesterolemia and hypertriglyceridemia. The use of lower doses (50 and 250 mg/kg b.w.) showed only therapeutic effects. It is further suggested that this antitumor effect might be due to its expected anti-inflammatory action, as well as by mechanisms not directly dependent of COX-2 inhibition, such as cellular proliferation control and improvement in antioxidant profile.info:eu-repo/semantics/publishedVersio
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