187 research outputs found

    Environmental Risks, Challenges and Opportunities Along the African Belt and Road Initiative

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    China’s Belt and Road Initiative (BRI) is playing a central role in the infrastructure development of Africa, with investments centered in the transportation and energy sectors, aiming to promote the long-desired growth of trade routes between and within African regions and the world. The expansion of transportation infrastructures, seaports and airports, as well of power-lines and other linear infrastructures, is expected to foster the development of industries and economy, by improving the connectivity between human settlements and main trade hubs. However, despite the expected benefits for human well-being, the feedback of development boosted by the BRI may come with a high toll for the environment in Africa. I briefly discuss how this major development driver may threaten Africa’s unique biodiversity. Also, I highlight some unpredicted costs of infrastructures that may jeopardize the economic growth and prosperity and identify big challenges for the pacific implementation of the BRI, namely the lack of environmental commitment by Chinese companies abroad, and the poor governance in African countries. I also identify great opportunities to be pursued for sustainable coexistence between development and conservation, including broadening education to more populations, and increasing food production.info:eu-repo/semantics/acceptedVersio

    Red mud-based geopolymers with tailored alkali diffusion properties and pH buffering ability

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    This study develop novel porous red mud (RM) based geopolymers and evaluates their potential to ensure prolonged pH control. Several properties of the novel geopolymers were examined including buffering ability, alkalis leaching behaviour, mineralogical composition, microstructure and physical properties. Two experimental plans were defined to evaluate the influence of porosity and RM content on those properties. The pH values of the eluted water and geopolymers OH ions leaching have been determined over time showing that total OH ions and the leaching rate can be tailored by controlling the geopolymers porous structure and the availability of free alkaline species. The lower pH gradient over 28th d (1.64 pH units) was achieved by combining a 0.025 wt% pore forming agent (aluminium powder) with 45 wt% MK replacement by red mud. A high and prolonged buffer capacity was accomplished, proving that red mud-based geopolymers have potential to be applied as pH buffering material.This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement.info:eu-repo/semantics/publishedVersio

    Functionalized cork-polymer composites (CPC) by reactive extrusion using suberin and lignin from cork as coupling agents

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    High density polyethylene (HDPE) and cork powder were compounded in a co-rotating twin-screw extruder to obtain cork-polymer composites (CPC) with improved properties. Benzoyl peroxide (BPO) was used as initiator agent, and suberin or lignin isolated from cork enhanced filler-matrix bonding and promoted mechanical reinforcement with environmental benefits. The novel composites were characterised in terms of dimensional stability, evolution of morphology, thermal and mechanical properties and their performance was compared with that of composites containing polyethylene-grafted maleic anhydride (PE-g-MA) as coupling agent. As expected, composites with coupling agent present higher mechanical properties, lower water uptake and thickness swelling variation. Suberin acts as plasticizer with antioxidant benefits, while lignin works as a coupling agent, improving tensile modulus and maximum strength. Increasing lignin content does not improve the mechanical properties but improves thermal stability.The work was performed within the project of Corticeira Amorim S.G.P.S. on the development of new products based in/with cork. The authors gratefully acknowledge the financial support, through the COMPETE/QREN/EU funding program in the project with acronym NovelComp (QREN FCOMP-01-0202-FEDER-003107). The authors acknowledge the Portuguese Foundation for Science and Technology (FCT) and POPH/FSE for the doctoral Grants to E.M.F. (SFRH/BD/71561/2010) and I.M.A. (SFRH/BD/42273/2007)

    Cork extractives exhibit thermo-oxidative protection properties in polypropylene-cork composites and as direct additives for polypropylene

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    The thermo-oxidative stability of polypropylene (PP) in composites containing 15 wt.% of cork and the performance of selected cork extracts as stabilizing additives for PP was evaluated by Oxidation Induction Time (OIT) and by Oxidation Onset Temperature (OOT). The results showed that cork increases the OIT of PP in the composite and it was identified that the cork extractives fraction is responsible for such behavior. Selected cork extracts with high antioxidant capacity (determined by dpph radical scavenging and oxygen reactive absorbance capacity assays) were compounded by extrusion with PP in 0.5 and 1.5 wt.%. It was found that the ethanol extract is the most effective as thermo-oxidative stabilizer for PP. At the loading level of 1.5%, the OIT increases from 3.8 (neat PP) to 29.7 min at 200 Â°C and from 1.2 (neat PP) to 9.0 min at 220 Â°C. The OOT also increases from 216 Â°C (neat PP) to 247 Â°C. Mechanical tests, performed on PP loaded with the cork extracts, showed that the presence of these extracts has no significant effect on the polymer mechanical performance. The results demonstrate the suitability of cork as a source of thermo-oxidative stabilizing additives for the formulation of polyolefins, and enable the exploitation of new routes of cork valorization.The authors are grateful to Amorim Cork Composites for providing the cork powder raw material. Ivo Aroso and Emanuel Fernandes are grateful for financial support of FCT through grants SFRH/BD/42273/2007 and SFRH/BPD/96197/2013, respectively. Funding was also granted from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no REGPOT-CT2012-316331-POLARIS and from Project "Novel smart and biomimetic materials for innovative regenerative medicine approaches (Ref.: RL1-ABMR-NORTE-01-0124-FEDER-000016)" co-financed by North Portugal Regional Operational Programme (ON.2 - O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF)

    Monitoring Hg and Cd contamination using red swamp crayfish (Procambarus clarkii): implications for wetland food chain contamination

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    Environmental pollution is one of the most serious causes of degradation of Mediterranean wetlands. Mercury (Hg) and cadmium (Cd) are of particular concern due to biomagnification. Here, we used red swamp crayfish (Procambarus clarkii) to monitor the spatial and temporal patterns of these two metals in a Portuguese rice field system. We sampled the crayfish in three different sites and three different time periods in the Sado River Basin (Portugal). We measured temperature, pH, total dissolved solids and conductivity in the water. Hg and Cd were measured in the crayfish abdominal muscle tissue and exoskeleton. In muscle, a spatial pattern was found for the accumulation of Cd while for Hg, only a temporal pattern emerged. The spatial pattern for Cd seemed to reflect the mining history of the sites, whereas the temporal pattern for Hg seemed related to the flooding of rice fields. We suggest that this flooding process increases Hg bioavailability

    Bone mineral density of the lumbar spine of Brazilian children and adolescents aged 6 to 14 years

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    The authors performed a study of bone mass in eutrophic Brazilian children and adolescents using dual-energy X-ray absorptiometry (DXA) in order to obtain curves for bone mineral content (BMC) and bone mineral density (BMD) by chronological age and correlate these values with weight and height. Healthy Caucasian children and adolescents, 120 boys and 135 girls, 6 to 14 years of age, residents of São Paulo, Brazil, were selected from the Pediatric Department outpatient clinic of Hospital São Paulo (Universidade Federal de São Paulo (UNIFESP)). BMC, BMD and the area of the vertebral body of the L2-L4 segment were obtained by DXA. BMC and BMD for the lumbar spine (L2-L4) presented a progressive increase between 6 and 14 years of age in both sexes, with a distribution that fitted an exponential curve. We identified an increase of mineral content in female patients older than 11 years which was maintained until 13 years of age, when a new decrease in the velocity of bone mineralization occurred. Male patients presented a period of accelerated bone mass gain after 11 years of age that was maintained until 14 years of age. At 14 years of age the mean BMD values for boys and girls were 0.984 and 1.017 g/cm², respectively. A stepwise multiple regression analysis of paired variables showed that the vertebral area-age pair was the most significant in the determination of BMD values and the introduction of a third variable (weight or height) did not significantly increase the correlation coefficient.Universidade Federal do Rio Grande do Norte Departamento de PediatriaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de MedicinaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PediatriaUNIFESP, EPM, Depto. de MedicinaUNIFESP, EPM, Depto. de PediatriaSciEL

    Water and carbon dioxide: green solvents for the extraction of collagen/gelatin from marine sponges

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    "Publication Date (Web): December 23, 2014"Marine sponges are extremely rich in natural products and are considered a promising biological resource. The major objective of this work is to couple a green extraction process with a natural origin raw material to obtain sponge origin collagen/gelatin for biomedical applications. Marine sponge collagen has unique physicochemical properties, but its application is hindered by the lack of availability due to inefficient extraction methodologies. Traditional extraction methods are time consuming as they involve several operating steps and large amounts of solvents. In this work, we propose a new extraction methodology under mild operating conditions in which water is acidified with carbon dioxide (CO2) to promote the extraction of collagen/gelatin from different marine sponge species. An extraction yield of approximately 50% of collagen/gelatin was achieved. The results of Fourier transformed infrared spectroscopy (FTIR), circular dichroism (CD), and differential scanning calorimetry (DSC) spectra suggest a mixture of collagen/gelatin with high purity, and the analysis of the amino acid composition has shown similarities with collagen from other marine sources. Additionally, in vitro cytotoxicity studies did not demonstrate any toxicity effects for three of the extracts.The authors are grateful for financial support of FCT through Grant EXP/QEQ:EPS/0745/2012, SWIMS (Subcritical Water Isolation of compounds from Marine Sponges). The funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement numbers REGPOT-CT2012-316331-POLARIS and KBBE-2010-266033 (project SPECIAL), as well as from ERDF under the project "Novel smart and biomimetic materials for innovative regenerative medicine approaches" RLI-ABMR-NORTE-01-0124-FEDER-000016), cofinanced by North Portugal Regional Operational Programme (ON.2,O Novo Norte), under the National Strategic Reference Framework (NSRF) are also gratefully ackowledged. The authors are also truly thankfull to Prof. Micha flan (Tel Aviv University, Israel), Dr. Ronald Osinga (Porifarma, The Netherlands), Dr. Antonio Sara and Dr. Martina Milanese (Studio Associato GAIA, Italy), and Dr. Joana Xavier (University of Azores) for the kind offer of marine sponges samples

    Surface modification of silica-based marine sponge bioceramics induce hydroxyapatite formation

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    Marine biomaterials are a new emerging area of research with significant applications. Recently, researchers are dedicating considerable attention to marine-sponge biomaterials for various applications. We have focused on the potential of biosilica from Petrosia ficidormis for novel biomedical/industrial applications. A bioceramic structure from this sponge was obtained after calcination at 750ºC for 6 hours in a furnace. The morphological characteristics of the 3D architecture were evaluated by scanning electron microscopy (SEM) and micro-computed tomography revealing a highly porous and interconnected structure. The skeleton of Petrosia ficidormis is a siliceous matrix composed of SiO2, which does not present inherent bioactivity. Induction of bioactivity was attained by subjecting the bioceramics structure to an alkaline treatment (KOH 2M) and acidic treatment (HCl 2M) for 1 and 3 hours. In vitro bioactivity of the bioceramics structure was evaluated in simulated body fluid (SBF), after 7 and 14 days. Observation of the structures by SEM, coupled with spectroscopic elemental analysis (EDS), has shown that the surface morphology presented a calcium-phosphate CaP coating, similar to hydroxyapatite (HA). The determination of the Ca/P ratio, together with the evaluation of the characteristic peaks of HA by infra-red spectroscopy and X-ray diffraction, have proven the existence of HA. In vitro biological performance of the structures was evaluated using an osteoblast cell line andthe acidic treatment has shown to be the most effective treatment. Cells were seeded on the bioceramics structures and their morphology, viability and growth was evaluated by SEM, MTS assay and DNA quantification, respectively, demonstrating that cells are able to grow and colonize the bioceramic structures.Alexandre Barros is grateful for financial support of FCT through Grant EXP/QEQ-EPS/0745/2012, SWIMS - Subcritical Water Isolation of compounds from Marine Sponges. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under Grant REGPOT-CT2012-316331-POLARIS and under Grant no KBBE-2010-266033 (project SPECIAL). Funding from the project "Novel smart and biomimetic materials for innovative regenerative medicine approaches" RL1-ABMR-NORTE-01-0124-FEDER-000016) cofinanced by North Portugal Regional Operational Programme (ON.2 - O Novo Norte), under the National Strategic Reference Framework (NSRF) is also acknowledged

    Improvement on the mechanical properties of cork composites using suberin as coupling agent through a reactive extrusion process

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    New functionalized composite structures were prepared using low-density polyethylene (LDPE), cork powder and different suberins extracted from cork and birch outer bark as coupling agents to promote interfacial adhesion. The compounding was performed under reactive extrusion and samples processed by compression moulding. The morphology of the functionalized composites showed good adhesion between cork and the polymeric phase. The mechanical results confirm that the addition of suberin acts as coupling agent improving the strength and leads to cork-polymer composite materials with improved strain and lower modulus. When the suberin was added to the composition a slight increase on the composite density occurred. The new cork-polymer composites demonstrated that this technological approach is industrially appealing.QREN FCOMP-01-0202-FEDER-003107 finance support on the project ”NovelComp”.Portuguese Foundation for Science and Technology (FCT).European project FP6 of Wacheup: New concepts for upgrading pulp and cork mill waste streams to value-added chemicals.Corticeira Amorim S.G.P.S. on the development of new products based in/with cork and for the supply of cork materials
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