2,189 research outputs found

    Chitosan and polyethylene glycol based membranes with antibacterial properties for tissue regeneration

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    The prevention of microbial infections associated with implantable medical devices and superficial wounds represents one of the main research strategies in the field of biomaterials. The present study reports on the development of composite membranes of Chitosan (CS)-Polyethylene glycol (PEG) matrix, incorporating particles of biphasic calcium phosphate (BCP), zinc oxide (ZnO) and copper oxide (CuO). The properties that are relevant for intended applications in tissue regeneration and antibacterial coatings of implants were assessed. It was found that the addition of 1% (w/w - relative to the mass of CS) of each metal oxide promoted satisfactory bacteriostatic activity and exhibited no cytotoxic effects towards the Vero cell line. The formation of bonds between the CS/PEG matrix and ionic species from the powders enhanced the cross-linking degree and mechanical properties of composite membranes in comparison to the non-doped membrane with the same polymer matrix (CS/PEG‚ÄĮ=‚ÄĮ70/30%). A gradual degradation of the composite membranes over the immersion time in simulated body fluid (SBF) was accompanied by a continuous surface deposition of uniform apatite layer.publishe

    Estudio y análisis de un nuevo dispositivo para la rehabilitación de la articulación tibiotarsal

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    Introduction: Currently, there are several types of devices and techniques for the rehabilitation of the tibiotarsal joint. However, complete and effective rehabilitation still falls short of expectations, since the existing devices are not adaptable to the level of torque and the number of repetitions and sessions to be performed, as these depend on each patient and on the stage at which he is finds. Objetives: To improve a mechatronic device for the rehabilitation of the tibiotarsal joint, the Therapheet. Methods: This study presents a review of the tibiotarsal joint rehabilitation protocols, as well as the classification of devices used for this purpose. Thus, the purpose is to improve the Therapheet, developed at the Department of Mechanical Engineering of the University of Minho, obtaining a viable, functional and safe rehabilitation device, standing out from the rest on the market, since it allows the execution of the six rehabilitation exercises. Results: It was obtained a prototype of equipment for rehabilitation of the tibiotarsal joint was obtained, proposing changes for improvement according to the specificities and requirements for such a device, having been subjected to a series of preliminary tests to verify its functionality, performance and suitability. The equipment proved to be functional, in terms of executing the ankle rehabilitation movements, however, it still manifests some flaws in terms of the user's stability, sudden movements, and above all dysfunctions arising from excess mass that make up its structure and limitations pneumatic technology adopted. Conclusions: The control of the amplitude of the characteristic angles of the movements of the foot is still done manually, so it would be significant to implement an automated system that would allow the control of the range of amplitude, according to the patient's rehabilitation phase. One option would be the implementation of a new technology, such as the insertion of servomotors.Introdu√ß√£o: Atualmente existem v√°rios tipos de dispositivos e t√©cnicas para a reabilita√ß√£o da articula√ß√£o tibiot√°rsica. No entanto, a reabilita√ß√£o completa e eficaz ainda est√° aqu√©m das expectativas, uma vez que os dispositivos existentes n√£o s√£o adapt√°veis ao n√≠vel do bin√°rio e do n√ļmero de repeti√ß√Ķes e sess√Ķes a executar, pois estas dependem de cada paciente e do est√°dio em que este se encontra. Objetivos: Melhorar um dispositivo mecatr√≥nico, de reabilita√ß√£o da articula√ß√£o tibiot√°rsica, o Therapheet. M√©todos: Neste estudo √© apresentada uma revis√£o dos protocolos de reabilita√ß√£o da articula√ß√£o tibiot√°rsica, assim como a classifica√ß√£o dos dispositivos utilizados para este prop√≥sito. Assim, a finalidade √© aperfei√ßoar o Therapheet, desenvolvido no Departamento de Engenharia Mec√Ęnica da Universidade do Minho, obtendo-se um dispositivo de reabilita√ß√£o vi√°vel, funcional e seguro, destacando-se dos restantes no mercado, uma vez que permite a executa√ß√£o dos seis exerc√≠cios de reabilita√ß√£o. Resultados: Foi obtido um prot√≥tipo de equipamento para reabilita√ß√£o da articula√ß√£o tibiot√°rsica, propondo altera√ß√Ķes de melhoria de acordo com as especificidades e os requisitos necess√°rios para um dispositivo deste tipo, tendo sido submetido a uma s√©rie de testes preliminares para verificar a sua funcionalidade, desempenho e adequabilidade. O equipamento demonstrou ser funcional, a n√≠vel de execu√ß√£o dos movimentos de reabilita√ß√£o do tornozelo, no entanto, ainda manifesta algumas falhas ao n√≠vel da estabilidade do utilizador, movimentos bruscos, e sobretudo disfun√ß√Ķes provenientes de excesso de massa que comp√Ķe a sua estrutura e de limita√ß√Ķes da tecnologia pneum√°tica adotada. Conclus√Ķes: O controlo da amplitude dos aŐāngulos caracteriŐĀsticos dos movimentos do peŐĀ ainda eŐĀ feito manualmente, pelo que seria significativa a implementacŐßaŐÉo de um sistema automatizado que possibilitasse o controlo da graduacŐßaŐÉo da amplitude, de acordo com a fase de reabilitacŐßaŐÉo do paciente. Uma opcŐßaŐÉo seria a implementacŐßaŐÉo de uma nova tecnologia, como a insercŐßaŐÉo de servomotores.Introducci√≥n: Actualmente, existen varios tipos de dispositivos y t√©cnicas para la rehabilitaci√≥n de la articulaci√≥n tibiotarsal. Sin embargo, la rehabilitaci√≥n completa y efectiva a√ļn no cumple con las expectativas, ya que los dispositivos existentes no son adaptables al nivel de torque y al n√ļmero de repeticiones y sesiones a realizar, ya que dependen de cada paciente y la etapa en la que se encuentra. Objetivos: Mejorar un dispositivo mecatr√≥nico para la rehabilitaci√≥n de la articulaci√≥n tibiotarsal, el Therapheet. M√©todos: Este estudio presenta una revisi√≥n de los protocolos de rehabilitaci√≥n de la articulaci√≥n tibiotarsal, as√≠ como la clasificaci√≥n de los dispositivos utilizados para este prop√≥sito. Por lo tanto, el prop√≥sito es mejorar un dispositivo mecatr√≥nico desarrollado en el Departamento de Ingenier√≠a Mec√°nica de la Universidad de Minho, el Therapheet, obteniendo un dispositivo de rehabilitaci√≥n viable, funcional y seguro, que se destaque del resto en el mercado, ya que permite la ejecuci√≥n de los seis ejercicios de rehabilitaci√≥n. Resultados: Se obtuvo un prototipo de equipo para la rehabilitaci√≥n de la articulaci√≥n tibiotarsal, proponiendo cambios para mejorar de acuerdo con las especificidades y requisitos de dicho dispositivo, habiendo sido sometido a un serie de pruebas preliminares para verificar su funcionalidad, rendimiento e idoneidad. El equipo demostr√≥ ser funcional, en t√©rminos de ejecuci√≥n de los movimientos de rehabilitaci√≥n de tobillo, sin embargo, todav√≠a presenta algunos defectos en t√©rminos de estabilidad del usuario, movimientos bruscos y, sobre todo, disfunciones derivadas del exceso de masa que conforman su estructura y limitaciones. Tecnolog√≠a neum√°tica adoptada. Conclusi√≥ns: El control de la amplitud de los √°ngulos caracter√≠sticos de los movimientos del pie todav√≠a se realiza manualmente, por lo que ser√≠a importante implementar un sistema automatizado que permita el control del rango de amplitud, de acuerdo con la fase de rehabilitaci√≥n del paciente. Una opci√≥n ser√≠a la implementaci√≥n de una nueva tecnolog√≠a, como la inserci√≥n de servomotores.This work has been supported by FCT ‚Äď Funda√ß√£o para a Ci√™ncia e Tecnologia with-in the R&D Units Project Scope: UIDP/04077/2020. It has been also supported by FCT ‚Äď Funda√ß√£o para a Ci√™ncia e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020

    Selection of a new peptide homing SK-BR-3 breast cancer cells

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    Breast cancer diagnosis remains a challenge, mostly due to its heterogeneity. This reality translates in delayed treatments, increasing treatment aggressiveness and lower chances of overall survival. The conventional detection techniques, although becoming increasingly sophisticated each year, still lack the ability to provide reliable conclusions without being time consuming, expensive and uncomfortable for the patients. The identification of novel biomarkers for breast cancer research is therefore of utmost relevance for an early diagnosis. Moreover, breast cancer specific peptide moieties can be used to develop novel targeted drug delivery systems. In this work we used phage display to identify a novel peptide with specificity to the SK-BR-3 breast cancer cell line. Cytometry assays confirmed its specificity, while bioinformatics and docking studies predicted the potential biomarkers at the SK-BR-3 cells surface. These findings can be potentially useful in the clinical context, contributing to more specific and targeted therapeutic solutions against HER2-positive breast cancer subtypes.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. Débora Ferreira and Ana Cláudia Pereira are recipient of fellowships supported by a doctoral advanced training (call NORTE-69-2015-15) funded by the European Social Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. Cátia Santos-Pereira acknowledges the PhD fellowship PD/BD/128032/2016 funded by FCT under the scope of the doctoral programme in Applied and Environmental Microbiology (DP_AEM). The authors also acknowledge César Pimenta from NOVA Institute of Chemical and Biological Technology António Xavier (NOVA ITQB) for the docking insights.info:eu-repo/semantics/publishedVersio

    Yeast as a tool to explore cathepsin D function

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    Cathepsin D has garnered increased attention in recent years, mainly since it has been associated with several human pathologies. In particular, cathepsin D is often overexpressed and hypersecreted in cancer cells, implying it may constitute a therapeutic target. However, cathepsin D can have both anti- and pro-survival functions depending on its proteolytic activity, cellular context and stress stimulus. Therefore, a more detailed understanding of cathepsin D regulation and how to modulate its apoptotic functions is clearly needed. In this review, we provide an overview of the role of cathepsin D in physiological and pathological scenarios. We then focus on the opposing functions of cathepsin D in apoptosis, particularly relevant in cancer research. Emphasis is given to the role of the yeast protease Pep4p, the vacuolar counterpart of cathepsin D, in life and death. Finally, we discuss how insights from yeast cathepsin D and its role in regulated cell death can unveil novel functions of mammalian cathepsin D in apoptosis and cancer.FEDER through POFC ‚Äď COMPETE and by Funda√ß√£o para a Ci√™ncia e Tecnologia through projects PEst-OE/BIA/UI4050/2014 and FCTANR/BEX-BCM/0175/2012, as well as fellowships to H. Pereira (SFRH/BD/73139/2010), C.S.F. Oliveira (SFRH/BD/77449/2011), L. Castro (SFRH/BD/93589/2013) and S. Chaves (SFRH/ BPD/89980/2012).info:eu-repo/semantics/publishedVersio

    Toxin profile of two Gymnodinium catenatum strains from Iberian Coastal Waters

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    Gymnodinium catenatum has been the main species responsible for paralytic shellfish poisoning events along the Portuguese coast (Iberian Peninsula), causing bans on bivalve harvesting that result in huge economic losses. This work presents the characterization of two novel isolates of G. catenatum regarding their growth and toxin profiles. Laboratory growth experiments revealed that, although low growth rates were obtained during cultivation, the cell yields were high compared to those reported in the literature. Evaluation of the toxin profiles, by HPLC-FLD, essentially confirmed the typical composition of toxins of this regional population (Iberian Peninsula), namely, the absence or low representation of the toxins dcNEO, GTX1,4 and NEO and a higher ratio of the toxins C1,2, GTX6 and GTX5. However, the percentage of the identified toxins varied among the strains of this study (under the same isolation, growth, and analysis conditions), and also differed from that of other strains described in the literature. Interestingly, we found a comparatively high abundance of dcSTX in both strains, relative to the other toxins, and an unquantifiable amount of C3,4 toxins. In addition to the geographic relationship between toxin profiles, chemical conversions among toxins may explain some differences encountered in the toxin profiles of G. catenatum strains.info:eu-repo/semantics/publishedVersio

    Valorization of sugarcane by-products through synthesis of biogenic amorphous silica microspheres for sustainable cosmetics

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    Ashes from sugarcane by-product incineration were used to synthesize silica powders through alkaline hot extraction, followed by ethanol/acid precipitation or the sol‚Äďgel method. Both production methods allowed amorphous spherical silica microparticles with sizes ranging from 1‚Äď15 őľm and 97% purity to be obtained. Water absorption ranged from 135‚Äď155 mL/100 g and 150‚Äď250 mL/100 g for precipitated silica and silica gel, respectively, while oil absorption ranged from 305 to 390 and from 250 to 350 mL/100 g. The precipitation with ethanol allowed the recovery of 178 g silica/kg ash, with a lab process cost of EUR 28.95/kg, while the sol-gel process showed a yield of 198 g silica/kg ash with a cost of EUR 10.89/kg. The experimental data suggest that ash from sugarcane by-products is a promising source to be converted into a competitive value-added product, minimizing the environmental impact of disposal problems.info:eu-repo/semantics/publishedVersio

    A biorefinery from Nannochloropsis sp. microalga ‚Äď Energy and CO2 emission and economic analyses

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    Are microalgae a potential energy source for biofuel production? This paper presents the laboratory results from a Nannochloropsis sp. microalga biorefinery for the production of oil, high-value pigments, and biohydrogen (bioH2). The energy consumption and CO2 emissions involved in the whole process (microalgae cultivation, harvest, dewater, mill, extraction and leftover biomass fermentation) were evaluated. An economic evaluation was also performed. Oil was obtained by soxhlet (SE) and supercritical fluid extraction (SFE). The bioH2 was produced by fermentation of the leftover biomass. The oil production pathway by SE shows the lowest value of energy consumption, 177-245 MJ/MJprod, and CO2 emissions, 13‚Äď15 kgCO2/MJprod. Despite consuming and emitting c.a. 20% more than the SE pathway, the oil obtained by SFE, proved to be more economically viable, with a cost of 365‚ā¨/kgoil produced and simultaneously extracting high-value pigments. The bioH2 as co-product may be advantageous in terms of product yield or profit

    Influence of bacterial dynamics upon the final characteristics

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    The microbiological profile in raw milk cheeses is typically characterized by a multitude of microbial groups, with interactions among them throughout ripening that are not fully understood to date. Incidence of undesired microorganisms in raw cheesemaking milk, as is the case of either spoilage or even pathogenic ones, is a common trait in Portuguese traditional cheeses. Hence, they will likely contribute to the physicochemical changes occurring therein and, consequently, to the characteristics of the final product. In order to gain insight into their role, model cheese systems, manufactured as far as possible according to artisanal practices (except that the initial microbial load and biodiversity were controlled), were experimentally tested. Single contaminants, or a consortium thereof, were inoculated at two levels in sterilized raw ewe's milk, and duly combined with inocula containing one or two lactic acid bacteria normally found in those traditional cheeses. The physicochemical composition, organic acid profile, and evolution of both protein breakdown and rheology were monitored throughout a 60 d-ripening period. Modifications brought about within the cheese matrix as a result of microbial metabolism, especially those arising from the interaction between lactic acid bacteria and unwanted microorganisms, included the enhanced release of peptides and free amino acids, which in turn led to higher viscoelastic moduli. The final model cheeses could be well discriminated, based on the impact of the various inocula considered upon the levels of organic acids. Conversely, proteolysis and viscoelastic properties appeared to be essentially independent of the initial microflora.info:eu-repo/semantics/publishedVersio

    Ohmic heating polyphenolic extracts from vine pruning residue with enhanced biological activity

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    Vine Pruning residue was submitted to conventional heating and ohmic heating (OH) for the extraction of bioactive compounds and analyzed for total phenolic content (TPC), polyphenolic profile, antioxidant activity, antimicrobial activity and anticancer activity. The OH extracts were obtained using Low electric field (496.0 V/cm) or Intermediate electric field - IEF (840.0 V/cm). The tests were performed using 45 % (v/v) ethanol-water extraction solution at 80 ¬įC at different extraction times (20 to 90 min). The extract that stood out among the others concerning anticancer potential was the one obtained by OH when used, IEF, where the TPC was significantly higher than in the other extracts which correlated with higher antioxidant, antimicrobial and anti-proliferative activity on different tumor cell lines (HepG2, MDA-MB-231, MCF-7 and Caco2). Vine pruning OH extracts obtained using green solvents by an eco-friendly procedure were revealed as a source of compounds with relevant antioxidant and anticancer activity.This work has been carried out at the Biomass and Bioenergy Research Infrastructure (BBRI)- LISBOA-01-0145-FEDER-022059, supported by Operational Programme for Competitiveness and Internationalization (PORTUGAL2020), by Lisbon Portugal Regional Operational Programme (Lisboa 2020) and by North Portugal Regional Operational Programme (Norte 2020) under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) and has been supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 ‚Äď Programa Operacional Regional do Norte. Meirielly S. Jesus thanks her fellowship supported by the International Cooperation Program CNPq/CSFat the University of Minho financed by CNPq-Brazilian Federal Agency. Zlatina Genisheva thanks to FCT for the financial support (ref. SFRH/BPD/108868/2015). Ana Cristina Carvalho was supported by the INTERACT project ‚Äď ‚ÄúIntegrated Research Environment, Agro-Chain and Technology‚ÄĚ, no. NORTE-01-0145-FEDER-000017, in its line of research entitled ISAC, co-financed by the European Regional Development Fund (ERDF) through NORTE 2020 (North Regional Operational Program 2014/2020).info:eu-repo/semantics/publishedVersio
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