3,107 research outputs found

    Application of Nanoparticles in Cancer Treatment: A Concise Review

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    Timely diagnosis and appropriate antitumoral treatments remain of utmost importance, since cancer remains a leading cause of death worldwide. Within this context, nanotechnology offers specific benefits in terms of cancer therapy by reducing its adverse effects and guiding drugs to selectively target cancer cells. In this comprehensive review, we have summarized the most relevant novel outcomes in the range of 2010–2023, covering the design and application of nanosystems for cancer therapy. We have established the general requirements for nanoparticles to be used in drug delivery and strategies for their uptake in tumor microenvironment and vasculature, including the reticuloendothelial system uptake and surface functionalization with protein corona. After a brief review of the classes of nanovectors, we have covered different classes of nanoparticles used in cancer therapies. First, the advances in the encapsulation of drugs (such as paclitaxel and fisetin) into nanoliposomes and nanoemulsions are described, as well as their relevance in current clinical trials. Then, polymeric nanoparticles are presented, namely the ones comprising poly lactic-coglycolic acid, polyethylene glycol (and PEG dilemma) and dendrimers. The relevance of quantum dots in bioimaging is also covered, namely the systems with zinc sulfide and indium phosphide. Afterwards, we have reviewed gold nanoparticles (spheres and anisotropic) and their application in plasmon-induced photothermal therapy. The clinical relevance of iron oxide nanoparticles, such as magnetite and maghemite, has been analyzed in different fields, namely for magnetic resonance imaging, immunotherapy, hyperthermia, and drug delivery. Lastly, we have covered the recent advances in the systems using carbon nanomaterials, namely graphene oxide, carbon nanotubes, fullerenes, and carbon dots. Finally, we have compared the strategies of passive and active targeting of nanoparticles and their relevance in cancer theranostics. This review aims to be a (nano)mark on the ongoing journey towards realizing the remarkable potential of different nanoparticles in the realm of cancer therapeutics.info:eu-repo/semantics/publishedVersio

    Problemáticas da educação física I

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    Mitochondrial SNP markers to monitor evolutionary lineage ancestry in Apis mellifera mellifera conservation programs

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    The European dark honey bee, Apis mellifera mellifera , is threatened inmost of its native range, in part, due to introgressive hybridization with bees from the highly divergent C-lineage, mainly Apis mellifera carnica and Apis mellifera ligustica (De la Rúa et al. 2009; Pinto et al. 2014). Yet, the maintenance of locally adapted genetic diversity is critical for the population long-term survival and sustainability (De la Rúa et al. 2009; Meixner 2010). The growing awareness that genetic diversity is important for sustainable beekeeping led to implementation of different conservation and breeding programs throughout Europe, which are in need of reliable and costefficient molecular tools to accurately monitor Clineage introgression into A. m. mellifera (De la Rúa et al. 2009; Henriques et al. 2018a, b; Meixner 2010). The large mating flight distances and the polyandrous mating system make it challenging to preserve honey bee subspecies in an open conservation area where intruders can fly in (Neumann et al. 1999). It is therefore necessary to regularly control the genetic ancestry of new or superseded colonies.This work was financed by FEDER (Fundo Europeu de Desenvolvimento Regional) through the program COMPETE 2020–POCI (Programa Operacional para a Competitividade e Internacionalização) and by Portuguese funds through FCT (Fundação para a Ciência e a Tecnologia) in the framework of the project BeeHappy (POCI-01-0145-FEDER-029871). Melanie Parejo was supported by a mobility fellowship awarded from the Swiss National Science Foundation (SNSF).info:eu-repo/semantics/publishedVersio

    In vitro digestion of oil-in-water emulsions stabilized by whey protein nanofibrils

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    The effect of pH (3 and 7) and varied energy density of a high-pressure homogenization process on the stability of oil-in-water (O/W) emulsions stabilized by whey protein fibrils was evaluated. A dynamic digestion model comprising the simulation of stomach, duodenum, jejunum and ileum, has been used to evaluate O/W emulsions' behavior under gastrointestinal (GI) conditions. The emulsions did not separate phases during the storage period (7 days). The emulsions stabilized by whey protein fibrils were stable under simulated gastric conditions but were destabilized in the simulated intestinal conditions. In a similar way, the whey protein fibrils' dispersion showed a high resistance to proteolytic in vitro digestion by pepsin (gastric stage) but was more readily degraded by pancreatin (intestinal stage). This fact confirms the significant impact of the interfacial characteristics on emulsions' digestion. The percentage of free fatty acids (FFA) absorbed in the simulated intestinal conditions (jejunum and ileum) was much lower than the total percentage of FFA released due to the use of WPI fibrils as emulsifier. This work contributes to a better understanding about the behavior of O/W emulsions stabilized by whey protein fibrils within the GI tract; this knowledge is fundamental when considering the final application of this protein in food products.The authors would like to thank Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for the PhD fellowship and the financial support (CAPES/FCT n° 7362/14-5 and CAPES/FCT nº 349/ 13). The author Ana C. Pinheiro is recipient of a fellowship from the Fundação para a Ciência Tecnologia (FCT, Portugal) through grant SFRH/BPD/101181/2014. We acknowledge INCT/INOMAT for supporting TEM analysis of fibril characterization carried out by Douglas Soares da Silva. We also would like to acknowledge Daniel A. Madalena for the contribution with the representative schematic of the in vitro dynamic digestion system.info:eu-repo/semantics/publishedVersio

    Gathering tradition, sowing the future! Some examples linking formal and informal seed systems from the North of Portugal

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    Based on different experiences and informal networks, we describe and explore the relationships between formal and informal seed systems in the North of Portugal, and discuss how such an interaction may be of interest to create new farmers opportunities, to improve conservation strategies and to promote local knowledge and cultural diversity. The Portuguese Gene Bank (BPGV), located in Braga (North-western Portugal), conserves 42203 accessions of traditional varieties in ex-situ conditions, that are the result of multiple activities undertaken all over the country with farmers' participation and commitment. BPGV together with the association “ARDAL” promoted on farm conservation of some crops, like maize, rye and beans, and two of these produces are in the Arch of Taste of SLOW FOOD Foundation. “Joaquim Dantas”, a farmer from the Portuguese north-western mountains, is an example of farmers' fundamental role in conserving and use agricultural biodiversity. He partnered in a project led by the BPGV to promote on-farm conservation and use of crop diversity. Then he reintroduced maize landraces into cultivation and led different initiatives to bake particular maize bread highly demanded. “Colher para semear” is another association seeking to establish a Portuguese network of landraces. They are community seed savers and their project focus on gathering seeds and registering knowledge and practices aiming to reintroduce them into cultivation while sharing resources, promoting biodiversity and ecological production, cultural heritage, generational transmission and food supplies. The research project “Cultibos, Yerbas i saberes” carried out in Miranda do Douro, North-eastern Portugal, reports and documents local knowledge on traditional crops, homegardens and wild gathering. Using ethnobotanical methodologies, several former crops, whose seeds are still kept by some old farmers, were identified. The project promotes seed exchange and cultivation, providing valuable insights into old crops and more seeds to share between neighbours

    Estudo da Sensibilização aos Aeroalergenos Phl p 1, Phl p 5, Ole e 1 e Ole e 2 em Doentes com Patologia Alérgica Sazonal

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    Estudo da Sensibilização aos Aeroalergenos Phl p 1, Phl p 5, Ole e 1 e Ole e 2 em Doentes com Patologia Alérgica Sazonal Cátia Coelho2, Elsa Caeiro2,4, Maria Luísa Lopes1, Ana Filipa Lopes3, Raquel Ferro2, José Eduardo Moreira3, Célia Antunes3,4, Rui Brandão4,5 1Hospital de Santa Luzia, Elvas, Portugal; 2Sociedade Portuguesa de Alergologia e Imunologia Clínica (SPAIC), Lisboa, Portugal; 3Departamento de Química, Universidade de Évora, Portugal; 4Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Universidade de Évora, Portugal; 5 Departamento de Biologia, Universidade de Évora, Portugal Introdução: A sensibilização aos pólenes depende de vários factores nomeadamente do tipo de vegetação local e sabe-se que a sintomatologia não está apenas associada à exposição aos pólens mas também a partículas, algumas das quais resultantes da rotura dos grãos de pólen sendo posteriormente aerossolizadas. Objectivos: Relacionar a sensibilização de doentes com a concentração polínica atmosférica e a concentração de alguns dos respectivos aerolergenos. Métodos: Das consultas externas de Imunoalergologia dos hospitais de Évora e Elvas seleccionaram-se doentes que apresentavam queixas sazonais de rinite alérgica e asma brônquica, aos quais foram realizados testes cutâneos em Prick, standardizados, aos pólenes identificados na região. A 55 doentes foram realizados testes ao extracto de Phleum, aos seus alergénios Phl p 1 e Phl p 5, bem como aos extractos das restantes gramíneas e a 47 doentes foram realizados testes ao extracto de Olea, aos seus alergénios Ole e 1 e Ole e 2. Monitorizaram-se diariamente as partículas polínicas e os aeroalergenos mediante 2 colectores específicos para cada tipo. Resultados: A percentagem de doentes que é sensível aos 3 extractos de Phleum (Phleum total, Phl p 1 e Phl p 5) é de 51% , a dos que são sensíveis aos extractos de Phleum total e Phl p 1 é de 16 % e a dos que são sensíveis a Phleum total e Phl p5 é de 2%. A percentagem de doentes que é sensível a somente um dos extractos é de 20% e os que não têm qualquer sensibilidade são 11%. A percentagem de doentes que é sensível aos 3 extractos de Olea (Olea total, Ole e 1 e Ole e 2) é de 23%, a dos que são sensíveis à Olea total e Ole e 1 é de 21 % e a dos que são sensíveis à Olea total e Ole e 2 é de apenas 4%. A percentagem dos que são sensíveis a um dos extractos é de 19% e a dos que não apresentaram qualquer sensibilidade é de 32%. Conclusões: Podemos concluir que 89% dos doentes mostraram ser sensíveis aos alergénios da gramínea Phleum pratense pois mostraram positividade tanto ao extracto de Phleum e/ou aos seus alergénios Phl p 1 e Phl p 5. Em relação à oliveira, 44% dos doentes são alérgicos a este pólen pois são sensíveis ao seu alergénio major, Ole e 1. Em ambos os casos estão correlacionados com os aeroalergenos detectados nas amostras de ar, sendo a sensibilidade aos pólenes de gramíneas maior que a sensibilidade ao pólen de oliveira. Mais estudos devem ser realizados para despiste de reacções cruzadas nomeadamente quanto à Olea com outras plantas da região

    Differential effects of food restriction and warming in the two-spotted goby: impaired reproductive performance and stressed offspring

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    Climate change is a growing threat to marine organisms and ecosystems, and it is already modifying ocean properties by, for example, increasing temperature and decreasing pH. Increasing water temperature may also lead to an impairment of primary productivity and an overall depletion of available zooplankton. Understanding how the crossover between warming and zooplankton availability impacts fish populations has paramount implications for conservation and mitigation strategies. Through a cross factorial design to test the effects of ocean temperature and food availability in a temperate marine teleost, Pomatochistus flavescens, we showed that hindered feeding impacted sheltering and avoidance behaviour. Also, low food availability impaired fish reproduction, particularly male reproduction, as the expression of cyp11b1, a gene with a pivotal role in the synthesis of the most important fish androgen, 11-ketotestosterone, was significantly reduced under a low food regime. In contrast, temperature alone did not affect reproductive success, but offspring showed increased saturated fatty acid content (embryos) and increased lipid peroxidation (larvae). Altogether, food availability had a stronger effect on fitness, showing that coping with elevated temperatures, an ability that may be expected in shallow-water fish, can be indirectly impacted, or even overwhelmed, by the effects of ocean warming on primary productivity and downstream ecological processes.info:eu-repo/semantics/publishedVersio

    Phenolic composition and bioactivity of Lavandula pedunculata (Mill.) Cav. samples fromdifferent geographical origin

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    The aim of this study was to characterize the phenolic composition and evaluate the bioactivity of several samples of Lavandula pedunculata (Mill.) Cav, and to compare aqueous and hydroethanolic extracts. Plant materials were obtained by growing some accessions (seed samples) of various wild populations from different regions of Portugal conserved at the Portuguese Genebank in Braga. Phenolic compounds were analised by HPLC-DAD-ESI/MSn, antioxidant potential through in vitro assays (DPPH radical scavenging activity, reducing power and inhibition of lipid peroxidation), cytotoxicity on tumor cells (MCF-7, NCI-H460, HeLa and HepG2) and non-tumor (PLP2) cells, anti-inflammatory activity in rat RAW 264.7 macrophages, by the ability to inhibit NO production and antimicrobial potential by the microdilution method with INT dye (iodonitrotetrazolium chloride). Thirteen compounds were identified, being salvianolic acid B, rosmarinic acid and luteolin-7-O-glucuronide, the main compounds present, with values ranging between 44.3⁻582, 50.9⁻550, and 24.36⁻101.5 mg/g extract, respectively. L. pedunculata aqueous extract revealed a higher antioxidant potential (EC50 values between 14 to 530 μg/mL), which could be related to its higher concentration in phenolic compounds; however, the hydroethanolic extract showed a higher anti-inflammatory (lower EC50 values than 124 μg/mL) potential and antiproliferative capacity (lower GI50 values than 34 μg/mL). Thus, this study highlights the bioactive effects of this species and opens up possibilities of uses in food and pharmaceutical formulations. However, there are potential differences in such properties according to geographical origin of plant material, as in general, the samples from Alentejo presented higher results in all the bioactivities, compared with Trás-os-Montes samples.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), L. Barros and R. Calhelha contracts. The authors are grateful to FEDER-Interreg España-Portugal programme for financial support through the project 0377_Iberphenol_6_E.info:eu-repo/semantics/publishedVersio

    Allergen profile of soluble protein fraction of pollen from Quercus rotundifolia

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    Grasses and olive are the most relevant allergenic species in the Alentejo region. However, aggravation of allergic symptoms has been reported in the early spring, before grass and olive pollen seasons. Quercus pollen is the most abundant pollen type in the early spring in Alentejo, nonetheless its allergen profile has not yet been evaluated. The aim of this work was to characterize the allergen profile of pollen from Quercus rotundifolia the most representative species showing pollination in April, prior to the main pollen season in Alentejo. Pollen from Quercus rotundifolia and Olea europaea was extracted with ammonium bicarbonate buffer, lyophilized and stored at -80ºC until analysis. Extract from Quercus ilex pollen was kindly offered by Bial. Protein content was determined by the Bradford method. SDS-PAGE followed by western blot, using allergic patient sera (obtained from the Hospital do Espírito Santo de Évora – HESE), were performed to evaluate the allergen profile of the pollen. Protein profile of Q. rotundifolia has shown several bands in the Mr 10-94 KDa, mostly overlapping with Q. ilex. Western blot have shown 9 immunoreactive bands, identified in the Mr (7.5, 11.7-12.6, 18.7-19.0 and 20.9-23.6, 29.2-33.3, 40.9, 51.7, 75.9 and 83.7 KDa). Protein profile according to the pI showed four immunoreactive bands in the pI range 4.0-6.1. Cross-reactivity between Q. rotundifolia and O. europaea was found. These results evidenced allergens found in Q. rotundifolia pollen. It also shows that protein profile of Q. rotundifolia and Q. ilex are mostly alike suggesting that similarities in allergen profile are expected. Moreover, cross–reactivity between Q. rotundifolia and O. europaea was found which probably contributes for aggravation of pollinosis in the early spring

    Secret sharing-based authentication and key agreement protocol for machine-type communications

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    [EN] One of the main challenges for the development of the Internet of Things is the authentication of large numbers of devices/sensors, commonly served by massive machine-type communications, which jointly with long-term evolution has been considered one of the main foundations for the continued growth of Internet of Things connectivity and an important issue to be treated in the development of 5G networks. This article describes some protocols for the group-based authentication of devices/sensors in Internet of Things and presents a new group authentication protocol based on Shamir's secret and Lagrange interpolation formula. The new protocol protects privacy, avoids unauthorized access to information, and assists in the prevention of attacks, as replay, distributed denial of service, and man-in-the-middle. A security analysis and comparisons among the 3GPP evolved packet system authentication and key agreement standard protocol and other recent group authentication protocols were performed toward proving the efficiency of the proposed protocol. The comparisons regard security properties and computational and communication costs. The safety of the protocol was formally verified through simulations conducted by automated validation of internet security protocols and applications.Lopes, APG.; Hilgert, LO.; Gondim, PRL.; Lloret, J. (2019). Secret sharing-based authentication and key agreement protocol for machine-type communications. International Journal of Distributed Sensor Networks (Online). 15(4):1-21. https://doi.org/10.1177/1550147719841003S12115
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