Osteogenic differentiation of adipose stem cells by endothelial cells co-culture within liquified capsules

Inspired by the native co-existence of multiple cell types and from the concept of deconstructing the stem cell niche, we propose a co-encapsulation strategy within liquified capsules. The present team has already proven the application of liquified capsules as bioencapsulation systems1. Here, we intend to use the optimized system towards osteogenic differentiation. Capsules encapsulating adipose stem cells alone (MONO-capsules) or in co-culture with endothelial cells (CO-capsules) were maintained in endothelial medium with or without osteogenic differentiation factors. The suitability of the capsules for living stem and endothelial cells encapsulation was demonstrated by MTS and DNA assays. The osteogenic differentiation was assessed by quantifying the deposition of calcium and the activity of ALP up to 21 days. CO capsules had an enhanced osteogenic differentiation, even when cultured in the absence of osteogenic factors. Furthermore, osteopontin and CD31 could be detected, which respectively indicate that osteogenic differentiation had occurred and endothelial cells maintained their phenotype. An enhanced osteogenic differentiation by co-encapsulation was also confirmed by the upregulation of osteogenic markers (BMP-2, RUNX2, BSP) while the expression of angiogenic markers (VEGF, vWF, CD31) revealed the presence of endothelial cells. The proposed capsules can also act as a growth factor release system upon implantation, as showed by VEGF and BMP-2 quantification. These findings demonstrate that the co-encapsulation of stem and endothelial cells within liquified injectable capsules provides a promising strategy for bone tissue engineering.  

In vitro chondrogenic commitment of human Wharton's jelly stem cells by co-culture with human articular chondrocytes.

Wharton's jelly stem cells (WJSCs) are a potential source of transplantable stem cells in cartilage-regenerative strategies, due to their highly proliferative and multilineage differentiation capacity. We hypothesized that a non-direct co-culture system with human articular chondrocytes (hACs) could enhance the potential chondrogenic phenotype of hWJSCs during the expansion phase compared to those expanded in monoculture conditions. Primary hWJSCs were cultured in the bottom of a multiwell plate separated by a porous transwell membrane insert seeded with hACs. No statistically significant differences in hWJSCs duplication number were observed under either of the culture conditions during the expansion phase. hWJSCs under co-culture conditions show upregulations of collagen type I and II, COMP, TGFβ1 and aggrecan, as well as of the main cartilage transcription factor, SOX9, when compared to those cultured in the absence of chondrocytes. Chondrogenic differentiation of hWJSCs, previously expanded in co-culture and monoculture conditions, was evaluated for each cellular passage using the micromass culture model. Cells expanded in co-culture showed higher accumulation of glycosaminoglycans (GAGs) compared to cells in monoculture, and immunohistochemistry for localization of collagen type I revealed a strong detection signal when hWJSCs were expanded under monoculture conditions. In contrast, type II collagen was detected when cells were expanded under co-culture conditions, where numerous round-shaped cell clusters were observed. Using a micromass differentiation model, hWJSCs, previously exposed to soluble factors secreted by hACs, were able to express higher levels of chondrogenic genes with deposition of cartilage extracellular matrix components, suggesting their use as an alternative cell source for treating degenerated cartilage.

Estratégias pedagógicas na aprendizagem da emissão de som no clarinete: respiração, material e metodologias de estudo

Relatório de estágio de mestrado em Ensino de Música

Assessment of the efficiency of prefabricated hybrid composite plates (HCPs) for retrofitting of damaged interior RC beam–column joints

The effectiveness of prefabricated hybrid composite plates (HCPs) as a seismic retrofitting solution for damaged interior RC beam-column joints is experimentally studied. HCP is composed of a thin plate made of strain hardening cementitious composite (SHCC) reinforced with CFRP sheets/laminates. Two full-scale severely damaged interior beam-column joints are retrofitted using two different configurations of HCPs. The effectiveness of these retrofitting solutions mainly in terms of hysteretic response, dissipated energy, degradation of secant stiffness, displacement ductility and failure modes are compared to their virgin states. According to these criteria, both solutions resulted in superior responses regarding the ones registered in their virgin states.

Flexural strengthening of RC beams using hybrid composite plate (HCP): experimental and analytical study

Hybrid Composite Plate (HCP) is a reliable recently proposed retrofitting solution for concrete structures, which is composed of a strain hardening cementitious composite (SHCC) plate reinforced with Carbon Fibre Reinforced Polymer (CFRP). This system benefits from the synergetic advantages of these two composites, namely the high ductility of SHCC and the high tensile strength of CFRPs. In the materialstructural of HCP, the ultra-ductile SHCC plate acts as a suitable medium for stress transfer between CFRP laminates (bonded into the pre-sawn grooves executed on the SHCC plate) and the concrete substrate by means of a connection system made by either chemical anchors, adhesive, or a combination thereof. In comparison with traditional applications of FRP systems, HCP is a retrofitting solution that (i) is less susceptible to the detrimental effect of the lack of strength and soundness of the concrete cover in the strengthening effectiveness; (ii) assures higher durability for the strengthened elements and higher protection to the FRP component in terms of high temperatures and vandalism; and (iii) delays, or even, prevents detachment of concrete substrate. This paper describes the experimental program carried out, and presents and discusses the relevant results obtained on the assessment of the performance of HCP strengthened reinforced concrete (RC) beams subjected to flexural loading. Moreover, an analytical approach to estimate the ultimate flexural capacity of these beams is presented, which was complemented with a numerical strategy for predicting their load-deflection behaviour. By attaching HCP to the beams’ soffit, a significant increase in the flexural capacity at service, at yield initiation of the tension steel bars and at failure of the beams can be achieved, while satisfactory deflection ductility is assured and a high tensile capacity of the CFRP laminates is mobilized. Both analytical and numerical approaches have predicted with satisfactory agreement, the load-deflection response of the reference beam and the strengthened ones tested experimentally.

Comparative environmental life-cycle analysis of concretes using biomass and coal fly ashes as partial cement replacement material

Nowadays, the concrete production sector is challenged by attempts to minimize the usage of raw materials and energy consumption, as well as by environmental concerns. Therefore, it is necessary to choose better options, e.g. new technologies or materials with improved life-cycle performance. One solution for using resources in an efficient manner is to close the materials' loop through the recycling of materials that result either from the end-of-life of products or from being the by-product of an industrial process. It is well known that the production of Portland cement, one of the materials most used in the construction sector, has a significant contribution to the environmental impacts, mainly related with carbon dioxide emission. Therefore, the study and utilization of by-products or wastes usable as cement replacement in concrete can supply more sustainable options, provided that these type of concrete produced has same durability and equivalent quality properties as standard concrete. This work studied the environmental benefits of incorporating different percentages of two types of fly ashes that can be used in concrete as cement replacement. These ashes are waste products of power and heat production sectors using coal or biomass as fuels. The results showed that both ashes provide a benefit for the concrete production both in terms of environmental impact minimization and a better environmental performance through an increase in cement replacement. It is possible to verify that the incorporation of fly ashes is a sustainable option for cement substitution and a possible path to improve the environmental performance of the concrete industry.

Evaluation of the performance of recycled textile fibres in the mechanical behaviour of a gypsum and cork composite material

Given the need for using more sustainable constructive solutions, an innovative composite material based on a combination of distinct industrial by-products is proposed aiming to reduce waste and energy consumption in the production of construction materials. The raw materials are thermal activated flue-gas desulphurization (FGD) gypsum, which acts as a binder, granulated cork as the aggregate and recycled textile fibres from used tyres intended to reinforce the material. This paper presents the results of the design of the composite mortar mixes, the characterization of the key physical properties (density, porosity and ultrasonic pulse velocity) and the mechanical validation based on uniaxial compressive tests and fracture energy tests. In the experimental campaign, the influence of the percentage of the raw materials in terms of gypsum mass, on the mechanical properties of the composite material was assessed. It was observed that the percentage of granulated cork decreases the compressive strength of the composite material but contributes to the increase in the compressive fracture energy. Besides, the recycled textile fibres play an important role in the mode I fracture process and in the fracture energy of the composite material, resulting in a considerable increase in the mode I fracture energy.

Experimental assessment of an innovative strengthening material for brick masonry infills

The vulnerability of masonry infill walls has been highlighted in recent earthquakes in which severe inplane damage and out-of-plane collapse developed, justifying the investment in the proposal of strengthening solutions aiming to improve the seismic performance of these construction elements. Therefore, this work presents an innovative strengthening solution to be applied in masonry infill walls, in order to avoid brittle failure and thus minimize the material damage and human losses. The textilereinforced mortar technique (TRM) has been shown to improve the out-of-plane resistance of masonry and to enhance its ductility, and here an innovative reinforcing mesh composed of braided composite rods is proposed. The external part of the rod is composed of braided polyester whose structure is defined so that the bond adherence with mortar is optimized. The mechanical performance of the strengthening technique to improve the out-of-plane behaviour of brick masonry is assessed based on experimental bending tests. Additionally, a comparison of the mechanical behaviour of the proposed meshes with commercial meshes is provided. The idea is that the proposed meshes are efficient in avoiding brittle collapse and premature disintegration of brick masonry during seismic events.

Avaliação da concentração de mercúrio em sedimentos e material particulado no rio Acre, estado do Acre, Brasil

A avaliação dos teores de mercúrio em sistemas aquáticos sem influência direta de fontes antropogênicas conhecidas não tem sido conduzida com freqüência na região Amazônica. Visando contribuir para esclarecer a ocorrência de valores elevados de Hg em peixes consumidos pela população de Rio Branco - AC, o Instituto Evandro Chagas - IEC, realizou um estudo para quantificar os teores de Hg em sedimentos de fundo e material particulado no rio Acre e alguns afluentes, além da caracterização físico-química das águas entre as cidades de Brasiléia e Assis Brasil. As amostras de sedimentos foram peneiradas na fração < 250 mesh e o material particulado obtido por floculação com Al2SO4 . Uma massa de 250 mg dos materiais foram submetidos a digestão ácida e as determinações de Hg realizadas por Espectrofotometria de Absorção Atômica, com geração de vapor frio. Os parâmetros físico-químicos pH, condutividade elétrica, temperatura e sólidos totais dissolvidos, foram feitos no campo, por métodos potenciométricos. Os teores de Hg nos sedimentos de fundo variaram entre 0,018 e 0,184 mig g-1, com média de 0,054 ± 0,034 mig g-1, enquanto que no material particulado a variação foi de 0,067 a 0,220 mig g-1e média de 0,098 ± 0,037 mig g-1. As águas possuem características levemente ácidas indicadas pelos valores de pH que variaram entre 5,80 - 6,95. A condutividade elétrica variou de 151,60 - 1.151,00 miS cm-1. Os teores de Hg nos materiais analisados encontram-se dentro da faixa dos valores observados para os rios amazônicos "não poluídos". Entretanto, estudos complementares deverão ser implementados para elucidar a origem e os processos de biodisponibilidade do mercúrio.

The role of Pep4p, the vacuolar yeast protease ortholog of human cathepsin D, in mitochondria-dependent apoptosis

Doctoral Thesis (PhD Programm on Molecular and Environmental Biology)

Determinação dos elementos-traço (Zn, Co e Ni) em sedimentos da Plataforma Continental Amazônica sob influência da descarga do rio Amazonas

Esta pesquisa foi desenvolvida na Plataforma Continental Amazônica (PCA) no trecho compreendido entre os cabos Orange (AP) e Maguari (PA), para determinar os teores de Zn, Co e Ni nos sedimentos superficiais, identificando o papel dos sedimentos como fonte ou reserva de elementos-traço. A concentração dos elementos metálicos apresentou a seguinte associação: Zn > Ni > Co. Os sedimentos localizados na PCA podem ser considerados como sítio de ocorrência natural dos elementos metálicos, não havendo influência de fontes poluidoras na liberação destes para o sistema.

Para um (novo) modelo de intervenção penal na União Europeia: uma reflexão a partir do princípio de legalidade como limite material de atuação da Procuradoria Europeia

Tese de Doutoramento em Ciências Jurídicas (área de especialização em Ciências Jurídicas - Públicas)

Mineralogia e geoquímica dos perfis sobre sedimentos neógenos e quaternários da bacia do Solimões na região de Coari - AM

O estudo do intemperismo das rochas é uma ferramenta indispensável para entender a evolução paleoambiental do Cenozóico na Amazônia. Com esse objetivo foram estudados seis perfis intempéricos desenvolvidos a partir da Formação Solimões e um perfil do Quaternário da várzea do rio Solimões, no centro-leste do estado do Amazonas. As informações obtidas permitiram determinar o grau de evolução intempérica na região, além das suas características estruturais, mineralógicas e químicas. Os perfis desenvolvidos sobre a Formação Solimões são constituídos, de baixo para cima, pelos horizontes saprolítico (C), mosqueado (B) e solo (A), enquanto o perfil sobre a sedimentação quaternária é estruturado nos horizontes saprolito (C) e solo (A). São argilo-arenosos a areno-argilosos, cinzentos, amarelados, avermelhados e esbranquiçados e compõem-se de quartzo, caulinita, muscovita, illita e esmectita. Segundo as suas características os perfis são divididos em dois grupos: 1) perfis 2, 3, 4 e 5: são areno-argilosos, tem altos teores de SiO2, Hg e Zr e estão associados unicamente à Formação Solimões; 2) perfis 1, 6 e 7: são pelíticos, têm maiores conteúdos em esmectita, illita, muscovita, Al2O3, álcalis e elementos-traço, especialmente de Ba, Co, Li, Ni, Sr, V, Y e Zn, e agrupam parte dos perfis sobre a Formação Solimões e o sedimento quaternário. A semelhança geoquímica entre este último e parte dos perfis sobre a Formação Solimões sugere que esta pode ser a fonte pelo menos de parte do material depositado na várzea. O conjunto das características demonstra que os horizontes dentro de cada perfil são muito semelhantes entre si e, portanto, pouco evoluídos, apesar do clima atual quente e chuvoso da região de Coari (2300 mm.ano-1) promover intensa lixiviação. Conseqüentemente, por serem derivados dos sedimentos mais jovens da Bacia do Solimões, e, portanto sob ação recente do intemperismo, pode-se afirmar que a unidade que deu origem aos perfis na Formação Solimões foi exposta no Quaternário e que estes se encontram em desequilíbrio com as condições agressivas de lixiviação do ambiente laterítico reinantes na Amazônia pelo menos desde o Paleógeno.

Estudo de metais pesados (Co, Cu, Fe, Cr, Ni, Mn, Pb e Zn) na Bacia do Tarumã-Açu Manaus (AM)

Os resíduos gerados em domicílios incluem diversos produtos, como pesticidas, produtos farmacêuticos, detergentes, óleos de cozinha, metais pesados contidos em baterias e outros utensílios. Esses resíduos são lançados continuamente em aterro sanitário ou lixões em cidades como Manaus. O chorume produzido nesses aterros, quando não tratados, contamina recursos hídricos superficiais e subterrâneos. Neste estudo foi feita uma avaliação das conseqüências da liberação do chorume no sistema hídrico da bacia do Tarumã-Açu. Amostras de água e sedimento foram coletadas nos igarapés Matrinxã, Acará, Bolívia, bacia do Tarumã-Açu e dentro do aterro sanitário (Manaus - Amazonas - Brasil) em março 2001. As amostras de água foram filtradas em filtro Milipore (0,45 mm de poro) e, em seguida, tratadas com HNO3 concentrado. As amostras de sedimento foram peneiradas em malha de 0,053 mm e digeridas com HCl:HNO3 (1:3) a 150ºC. As concentrações de alguns metais pesados (Co, Cu, Fe, Cr, Ni, Mn, Pb e Zn) foram determinadas nas amostras de água e sedimento por espectrometria de absorção atômica de chama. Os resultados revelaram que a concentração dos metais pesados é muito acima dos permitidos pela resolução 357/2005 do CONAMA em praticamente todos os locais amostrados, mostrando que o Aterro Sanitário é um dos principais responsáveis pelo impacto ambiental observado nos corpos hídricos estudados. As análises dos componentes principais (PCA) e hierárquica de cluster (HCA), revelam que os pontos de coleta localizados dentro do aterro sanitário apresentam características diferentes dos outros locais amostrados. Além disso, o HCA e PCA mostraram que existe uma similaridade entre os pontos de coleta localizados fora do aterro o que permite afirmar que o chorume do aterro se dissolve por todo corpo hídrico estudado.