333 research outputs found

    3D‐printed cryomilled poly(ε‐caprolactone)/graphene composite scaffolds for bone tissue regeneration

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    In this study, composite scaffolds based on poly(caprolactone) (PCL) and non-covalently functionalized few-layer graphene (FLG) were manufactured by an extrusion-based system for the first time. For that, functionalized FLG powder was obtained through the evaporation of a functionalized FLG aqueous suspension prepared from a graphite precursor. Cryomilling was shown to be an efficient mixing method, producing a homogeneous dispersion of FLG particles onto the PCL polymeric matrix. Thereafter, fused deposition modeling (FDM) was used to print 3D scaffolds and their morphology, thermal, biodegradability, mechanical, and cytotoxicity properties were analysed. The presence of functionalized FLG demonstrated to induce slight changes in the microstructure of the scaffold, did not affect the thermal stability and enhanced significantly the compressive modulus. The composite scaffolds presented a porosity of around 40% and a mean pore size in the range of 300 μm. The cell viability and proliferation of SaOs-2 cells were assessed and the results showed good cell viability and long-term proliferation onto produced composite scaffolds. Therefore, these new FLG/PCL scaffolds comprised adequate morphological, thermal, mechanical, and biological properties to be used in bone tissue regeneration.The authors acknowledge the Portuguese Foundation for Science and Technology (FCT), the European program FEDER/COMPETE for the financial support through project LA ICVS/3Bs - 2015-2017 and to IPC (UID/CTM/50025/2013 and UID/CTM/50025/2016), and the scholarship SFRH/BD/87214/2012 granted to Eunice Cunha. Daniela Dias acknowledges the mobility grant from the BEAM project- Biomedical Engineering-EU Australian cooperation at master level, ICIECP Education Cooperation Programme (388414-EM-January 1, 2014-IT-ERA MUNDUS-ICIJMP). We also acknowledge Prof. Dietmar W. Hutmacher that kindly hosts Daniela Dias in the IHBI laboratory

    The Role of Liquid Biopsy in Early Diagnosis of Lung Cancer

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    Liquid biopsy is an emerging technology with a potential role in the screening and early detection of lung cancer. Several liquid biopsy-derived biomarkers have been identified and are currently under ongoing investigation. In this article, we review the available data on the use of circulating biomarkers for the early detection of lung cancer, focusing on the circulating tumor cells, circulating cell-free DNA, circulating micro-RNAs, tumor-derived exosomes, and tumor-educated platelets, providing an overview of future potential applicability in the clinical practice. While several biomarkers have shown exciting results, diagnostic performance and clinical applicability is still limited. The combination of different biomarkers, as well as their combination with other diagnostic tools show great promise, although further research is still required to define and validate the role of liquid biopsies in clinical practice.This work is financed by the ERDF—European Regional Development Fund through the Operational Programme for Competitiveness and Internationalization—COMPETE 2020 Programme and by National Funds through the Portuguese funding agency, FCT—Fundação para a Ciência e a Tecnologia within project POCI-01-0145-FEDER-030263. Authors thank Abílio Cunha and Francisco Correia for the illustration work. NC-M acknowledges the Portuguese Foundation for Science and Technology under Horizon 2020 Program (PTDC/PSI-GER/28076/2017)

    Graphene nanoribbons and nanoflakes from functionalized carbon precursors

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    The process of formation of graphene by exfoliation of carbon nanotubes (CNT) or graphite originates graphene nanoribbons (GNR) and graphene nanoflakes (GNF), respectively. These nanoparticles are expected to present interesting electronic properties, depending on their shape, size, and on their edge shape. Several methods for the unzipping of nanotubes were described in the literature [1]. The major limitations to the application of these methods are related to low yield, or to the formation of highly oxidized GNRs. The present work was motivated by the observation of the unzipping of functionalized CNT under ultra-high vacuum scanning tunneling microscopy (UHV STM) [2]. The CNTs under observation were functionalized by the 1,3-dipolar cycloaddition reaction [3], a potential route for the production of GNRs without oxidation. The formation of graphene flakes was observed when functionalized graphite was exfoliated under similar conditions as the CNT. The graphite was functionalized by the same procedure as the CNT.Fundação para a Ciência e a Tecnologia (FCT

    Levantamento de viveiros dos estados de Santa Catarina e Rio Grande do Sul cadastrados no RENASEM/MAPA.

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    O atendimento às premissas constantes no Novo Código Florestal Brasileiro (Lei Nº 12.651/2012), requer buscas por estratégias e espécies vegetais nativas que atendam a demanda de restauração ecológica e de adequação ambiental das propriedades rurais. Neste Contexto, conhecer a localização de viveiros e o conjunto de espécies nativas disponíveis, representa importante resposta ao atendimento a estas obrigações ambientais. O objetivo do trabalho foi geolocalizar os viveiros do estado do Rio Grande do Sul e Santa Catarina cadastrados no sistema RENASEM/MAPA, mapeando a distribuição dos mesmos. O estado gaúcho conta com 310 viveiros cadastrados, apresentando uma maior concentração na mesorregião Região Metropolitana de Porto Alegre (21 no município de Pareci Novo). Para o estado catarinense foram geolocalizados 545 viveiros com maior concentração nas mesorregiões Vale do Itajaí e Norte Catarinense (60 no município de Rio do Oeste e 32 em Laurentino).Suplemento. Edição dos Anais do 10 Congresso Brasileiro de Agroecologia; 6 Congresso Latino-americano de Agroecologia; 5 Seminário de Agroecologia do Distrito Federal e Entorno, Brasília, DF, set. 2017

    Uso de hidrogel e mulching na sobrevivência e crescimento de espécies arbustivas e arbóreas.

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    O objetivo da pesquisa foi avaliar a influência do uso de hidrogel e mulching de cobertura morta sobre a sobrevivência e crescimento de mudas de Rhododendron simsii, Schinus spp. (S. terebinthifolia e S. molle) e Cupressus lusitanica. Para isso foram instalados três blocos, contendo quatro tratamentos inteiramente casualizados: T1: Tratamento controle (irrigação tradicional, sem mulching); T2: aplicação de hidrogel e sem mulching, T3: aplicação de hidrogel e com mulching e T4: irrigação tradicional e com mulching. A sobrevivência foi próxima a 100% para todas as espécies e tratamentos. Não houve efeito dos tratamentos sobre as variáveis avaliadas para R. simsii. Para Schinus spp., o tratamento T3 resultou em incremento em diâmetro da base significativamente superior do que T4 (TCRd; F3,50 = 3,13; p = 0,03). Para C. lusitanica, todas as variáveis avaliadas tiveram efeito significativo e os tratamentos com hidrogel foram sempre superiores aos relativos à irrigação tradicional (diâmetro da base (cm): F3,111 = 66,5; p ≤ 0,01; altura total (cm): F3,113 = 5,69; p ≤ 0,01; TCRd: F3,113 = 5,14; p ≤ 0,01; TCRh: F3,111 = 6,52; p ≤ 0,01 e Área da Copa (cm2 ): F3,111 = 6,42; p ≤ 0,01). De forma geral, o hidrogel mostrou-se como o melhor sistema de disponibilidade de água, pois seu custo de implantação e manutenção é inferior ao sistema de irrigação por gotejamento e todas as espécies avaliadas apresentaram crescimento em altura e diâmetro igual ou superior à irrigação convencional

    Gypsum, soil scarification and succession planting as alternatives to mitigate compaction of Dystrophic Red-Yellow Latosol.

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    Understanding and quantifying the impact of soil management and use on its physical properties are essential to the development of sustainable agricultural systems. Thus, the aim of this study was to assess the effect of agricultural gypsum, soil scarification and succession planting on the physical attributes of dystrophic red-yellow latosol in Porto Velho, Rondônia state (RO), Brazil

    Biological Activities of Libidibia (Caesalpinia) ferrea

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    Libidibia ferrea has been used in folk medicine throughout Brazil, and this study evaluated the biological activities of crude extract (CE) as well as a partially purified fraction (F80) obtained from its pods. Results from the MTT assay revealed that only F80 inhibited NCI-H292 cell growth; however, neither CE nor F80 reduced HEp-2 cell growth or sarcoma 180 tumor weight with the in vivo assay. Acute oral toxicity of the extract and fraction was evaluated following the steps of Guideline 423, using female mice; LD50 for both preparations was determined as 2,500 mg/kg body weight. CE and F80 promoted a reduction of the leukocyte number and nitrite level in inflammatory exudates when the anti-inflammatory assay (carrageenan-induced peritonitis) was performed. CE and F80 inhibited writhing regarding antinociceptive activity (acetic acid-induced writhing response in mice). In conclusion, CE and F80 have no significant cytotoxic or antitumor activities in cell lines showing low toxicity and no action against tumors in vivo. Both preparations revealed anti-inflammatory and antinociceptive activities, corroborating the pharmacological basis of L. ferrea for ethnomedical use

    Resistência à penetração de um Latossolo Vermelho-Amarelo Distrófico sob diferentes manejos e métodos.

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    Os sistemas de manejo têm grande influência nas propriedades físicas do solo e estão relacionados com a compactação do solo. Assim, este trabalho teve o objetivo avaliar a resistência mecânica do solo à penetração de um Latossolo Vermelho-Amarelo distrófico sob diferentes manejos. O experimento foi desenvolvido no campo experimental da Embrapa Rondônia, no município de Porto Velho, RO, sendo coletadas amostras para as análises nas profundidades de 0 a 0,05; 0,05 a 0,10; e 0,10 a 0,20 m. Os penetrômetros utilizados foram: um eletrônico modelo MA-933/Marconi, e um automatizado de campo, modelo SOLO TRACK/Falker. Os tratamentos consistiam na ausência e adição de 2000 kg ha-1 de gesso agrícola, ausência e presença de escarificação do solo, e três sistemas de sucessão de culturas: SP (soja/pousio), SMP (soja/milho/pousio) e SMBP (soja/milho/braquiária/pousio).O delineamento experimental foi em blocos casualizados, em esquema fatorial 2x2x3 com oito blocos. Os dados foram submetidos à análise de variância, e quando constatada significância, as médias foram comparadas pelo teste de Scott-Knott ao nível de 5 % de probabilidade. Os sistemas de sucessão de culturas podem influenciar nas características físicas do solo, os menores valores de RP foram observados nos sistemas de sucessão SMBP e SMP. O penetrômetro MA-033 mostrou-se adequado para avaliação da resistência a penetração. Soil management systems have a great influence on soil physical properties and are related to soil compaction. This work aimed to evaluate the soil mechanical resistance to penetration of a dystrophic RedYellow Latosol (Oxisol) under different management. The experiment was carried out at Embrapa Rondônia experimental field, in Porto Velho, RO, Brazil. Samples were collected for analysis at depths from 0 to 0.05; 0.05 to 0.10; and 0.10 to 0.20 m. The penetrometers used were: an electronic model MA-933 / Marconi, and an automated field, model SOLO TRACK / Falker. The treatments consisted of the absence and addition of 2000 kg ha -1 of agricultural plaster, absence and presence of soil scarification, and three crop succession systems: SP (soybean / fallow), SMP (soybean / corn / fallow) and SMBP (soybean / maize / brachiaria / fallow). The experimental design was in randomized blocks, in a 2x2x3 factorial scheme with eight blocks. Data were subjected to analysis of variance, and when significance was found, means were compared by the Scott-Knott test at the 5% probability level. Crop succession systems can influence soil physical characteristics, the lowest PR values were observed in SMBP and SMP succession systems. The MA-933 was better to evaluate of mechanical penetration resistance
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