CEBs stabilised with geopolymeric binders: mechanical performance of dry-stack masonry

The sustainability in the building industry is currently a sounding topic, seeking the development of more environmental friendly building materials. The incorporation of industrial wastes and the reuse of construction and demolition waste (CDW) in the production of building materials are methods being used to solve this problem. Furthermore, these methods contribute to fulfilling the targets defined by European Union for the valorisation of non-hazard waste. The construction with compressed earth blocks (CEBs) stabilised with geopolymeric binders is a solution that can contribute to this objective by incorporating both CDW (excavation soil) and industrial wastes. Despite some recent research done on this topic, it still deserves further investigation. This paper intends to contribute to the development of this topic by presenting an experimental program, continuing previous research. The experimental program is addressed to the mechanical characterisation of a dry-stack CEB (stabilised with geopolymer obtained from alkaline activation of fly ash) masonry system, and includes the evolution of the strength of the CEBs with the curing time. In general, the evolution of the strength of the CEBs cured under ambient condition was shown to be a slow process, which can have implications on the production process.Portuguese Science and Technology Foundation (FCT) through the project FCOMP-01-0124-FEDER-028864 (FCT-PTDC/ECM-EST/2396/2012)

Influence of different protecting groups on the regioselectivity of the hydrotelluration reaction of hydroxy alkynes

The influence of protecting groups on the synthesis of regio- and stereodefined vinyl tellurides derived from the reaction of BuTeNa and propargylic- or homo-propargylic alcohols showed that TIPS silyl ether is useful as a regiodirecting group. The application of the methodology to the synthesis of a fragment of (±)-Seselidiol, a natural product, demonstrated the applicability of the new methodology

Mechanical performance of masonry made with CEB stabilised by alkali activated fly ashes

Ao longo dos últimos anos foi possível observar uma crescente preocupação ao nível da sustentabilidade e da preservação do meio ambiente. Este trabalho tem como principal objetivo prestar um contributo nesse sentido, nomeadamente através do desenvolvimento de ummaterial mais sustentável, com menor impacto ambiental, recorrendo a uma técnica que permite encarar os resíduos industriais como matérias-primas. A terra, como material de construção, tem já uma utilização milenar, comprovada pelos importantes monumentos que chegaram até aos nossos dias. A ativação alcalina, enquanto técnica para a produção de ligantes alternativos, tem demonstrado um grande potencial, evidenciado ao longo dos últimos anos. Através da utilização de solo e da ativação alcalina de cinzas volantes foi possível desenvolver um material para fabrico de blocos de terra compactada (BTC) com desempenho mecânico, quer a nível individual quer ao nível da própria alvenaria resultante, adequado ao funcionamento deste tipo de estrutura.Over the last years it was possible to observe an increasing concern in terms of sustainability and environmental preservation. This work aims to make a contribution in this direction, particularly through the development of a more sustainable material, with lower environmental impact, employing a technique that allows to face the industrial waste as raw materials. The earth as building material has a millenary use, proven by the important monuments that have survived till nowadays. The alkaline activation, while technique for the production of alternative binders, has shown a great potential, evidenced over the last years. Through the use of the soil and alkali activated fly ashes was possible to develop a material for the manufacture of compressed earth blocks (CEB) with mechanical performance, either individually or at the level of the masonry itself, suitable for use in this type of structure.FCT (Fundação para a Ciência e Ta ecnologia), através do ISISE, com o projeto IUD/ECI/04029/201

Fast decellularization process using supercritical carbon dioxide for trabecular bone

Decellularization is a process that consists on the removal of immunogenic cellular material from a tissue, so that it can be safely implanted as a functional and bioactive scaffold. Most decellularization protocols rely on the use of harsh chemicals and very long washing processes, leading to severe changes in the ultrastructure and loss of mechanical integrity. To tackle these challenges, supercritical carbon dioxide (scCO2) is herein proposed as an alternative methodology for assisting decellularization of porcine trabecular bone tissue and is combined, for the first time, with Tri(n-butyl) phosphate (TnBP). Histological and DNA analysis revealed that both TnBP and scCO2 were able to extract the DNA content from the scaffolds, being this effect more pronounced in treatments that used TnBP as a co-solvent. The combined protocol led to a decrease in DNA content by at least 90%, demon- strating the potential of this methodology and opening new possibilities for future optimizations.info:eu-repo/semantics/publishedVersio

Anfíbios de Santa Isabel do Rio Negro, Amazônia Brasileira.

No presente estudo fornecemos uma lista de espécies de anfíbios de Santa Isabel do Rio Negro na Amazônia Brasileira. As amostragens foram realizadas de março a abril de 2012 em dois conjuntos de trilhas de 3 km de extensão, usando os seguintes métodos: (1) armadilhas de interceptação e queda com cerca direcionadora; (2) amostragens visuais e auditivas simultâneas; (3) encontros ocasionais. As trilhas foram instaladas ao norte (rio Daraá) e ao sul (rio Ayuanã) do rio Negro. Registramos 40 espécies de anuros e uma espécie de salamandra, pertencentes a 20 gêneros e nove famílias. A composição de espécies foi comparada com as de 16 outros estudos desenvolvidos nas áreas de endemismo Guiana, Imeri e Jaú, onde a riqueza de espécies variou de 21 a 63, e a similaridade, de 23 a 100%. A anurofauna das duas áreas estudadas foi mais similar à de Flota Faro, localizada na Amazônia Oriental, do que à de um sítio mais próximo, Departamento del Guainía, Colômbia. O índice de similaridade foi extremamente variável entre os sítios da mesma ou de distintas áreas de endemismo. Esse padrão também foi observado nas análises de agrupamento. Como esperado, áreas geograficamente mais próximas foram mais similares na composição da anurofauna. No entanto, a anurofauna do Parque Nacional do Jaú (área de endemismo Jaú) foi mais similar à de Manaus (área de endemismo Guiana) do que à do rio Ayuanã, que pretence à mesma área de endemismo que o Parque Nacional do Jaú. Os limites das áreas de endemismo podem ser melhor definidos para outros vertebrados terrestres, como aves e mamíferos, do que para anfíbios e répteis Squamata.A species list of amphibians from Santa Isabel do Rio Negro in Brazilian Amazonia is provided. Collections were made from March–April 2012 along each of two 3-km trails with the following sampling methods: (1) pitfall traps with drift fences; (2) visual and auditory surveys; and (3) chance encounters. The trail at Daraá is north of the Rio Negro, whereas the other in Ayuanã is south of the river. Forty species of anurans and one salamander species representing 20 genera and nine families were recorded. The species composition was compared with those of 16 other studies conducted in the Guiana, Imeri, and Jaú areas of endemism, where species richness varies from 21–63, and similarity indices range from 23–100%. The anuran fauna at our sites resembles that of Flota Faro in eastern Amazonia more than it does that of the nearest site in the Departamento del Guainía of Colombia. The index of similarity is extremely variable between sites of the same and distinct areas of endemism. This pattern also was observed in the cluster analysis. As expected, geographically close areas have similar faunal compositions. However, the anuran fauna of Parque Nacional do Jaú (Jaú area of endemism) resembles that of Manaus (Guiana area of endemism) more closely than it does that of the Ayuanã River, which belongs to the same area of endemism as Parque Nacional do Jaú. The limits of the areas of endemism are better defined by the presence / absence of other terrestrial vertebrates, such as birds and mammals, than by the assemblage of amphibians and squamate reptiles

Melatonin reduces the severity of experimental amoebiasis

<p>Abstract</p> <p>Background</p> <p>Melatonin has immunomodulatory effects but very little is known about its influence in protozoan infections, such as <it>Entamoeba histolytica</it>, which causes amoebiasis, a disease with significant morbidity and mortality. In this study, we evaluated the effects of exogenous melatonin interference in experimental amoebiasis and on interactions between human blood cells and <it>E. histolytica </it>trophozoites.</p> <p>Methods</p> <p>The effect of melatonin was investigated in models of experimental amoebiasis in hamsters and rats by evaluating the area of necrosis induced by <it>E. histolytica</it>. The activity of melatonin on the interactions between leukocytes and amoebae was determined by examining leukophagocytosis. For <it>in vitro </it>tests, polymorphonuclear and mononuclear human blood leucocytes were incubated with <it>E. histolytica </it>trophozoites.</p> <p>Results</p> <p>The areas of amoebic necrosis were significantly reduced in animals treated with melatonin. Melatonin treatment increased leukophagocytosis but was associated with a greater number of dead amoebae.</p> <p>Conclusions</p> <p>These results suggest that melatonin may play a beneficial role in the control of amoebic lesions, raising the possibility that this drug may be used as an adjuvant in anti-amoebic therapy.</p