3,968 research outputs found

    Mortar with pet—Preliminary results

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    ICEER2019 - 6th International Conference on Energy and Environment Research: “Energy and environment: challenges towards circular economy”, 22 -25 July 2019, Aveiro, PortugalThe objective of this work is to evaluate the performance and feasibility of the use of coating mortars with the incorporation of ground polyethylene terephthalate (PET) waste. It was studied the performance of 1: 4 mortars in weight with partial replacement of the aggregate by PET residuals in different percentages (0%, 5% and 10%). Obtained results showed a decrease of the mechanical resistance of mortars in the inverse proportion of the use of PET residues of the mixture, an increase in resistance to water absorption by capillary action and a decrease in thermal conductivity. These results support the potential use of PET waste in coating mortars, thereby contributing to reduce the environmental impact caused by plastic waste. However, in order to be considered energy efficient, this new material needs further improvements.info:eu-repo/semantics/publishedVersio

    Estudos soroepidemiológico e molecular de infecção por EV-71 no Estado do Pará, Brasil

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    In many countries, the Enterovirus 71 (EV-71) Picornaviridae family is associated to hand, foot and mouth disease in addition to acute neurological diseases while in Brazil these viruses are more closely associated to the latter group. The aim of this research was to use the first EV-71 isolate of the Northern region of Brazil in molecular and seroepidemiologic studies. Two (2.2%) out of 88 stool samples (44 cases of AFP), collected from January 1998 to December 2000 were positive for EV-71 isolation (73442/PA/99). Nucleotide sequence of the gen that codifies the VP1 protein showed that isolate 73442/PA/99 was similar to the EV-71 strains belonging to genotype B - more closely identified with EV-71 from North America. Neutralization test with 389 sera samples collected from January 1998 to November 2001, from individuals ranging from 0 to 15 years of age living in the city of Belém, State of Pará showed the following results in relation to isolate 73442/PA/99 and prototype BrCr: a total of 207 individuals (53.2%) had neutralization antibodies to both viruses, 167 (42.9%) had no antibodies and 15 showed the presence of neutralizing antibodies to one of the two viruses. Only 20.2% of the children aged 0 to 3 had neutralizing antibodies to EV-71, indicating that these children were more susceptible to the infection. Both the seroprevalence study and VP1 sequencing were important to demonstrate the spread and the molecular pattern of the EV-71 circulating in the Northern Region of Brazil.Em muitos países, o Enterovírus 71 (EV-71) família Picornaviridae é associado a doença de pé-mão e boca e doenças neurológicas agudas enquanto que no Brasil esse vírus está mais associado às últimas. O objetivo desta pesquisa foi utilizar em estudos moleculares e soroepidemiológicos, o primeiro isolamento de EV-71 obtido na região norte do Brasil. No período de janeiro de 1998 a dezembro de 2000 foram coletadas 88 amostras (44 casos de PFA) de fezes das quais, duas (2,2%) foram positivas para EV-71 (73442/PA/99). A seqüência de nucleotídeos do gen que codifica a proteína VP1 mostrou que o isolado 73442/PA/99 foi similar às cepas de EV-71 pertencentes ao grupo B- mais próxima das norte americanas. Teste de neutralização com 389 amostras de soro colhidas no período de janeiro de 1998 a novembro de 2001, de indivíduos com idade de 0 a 15 anos residentes na cidade de Belém, Estado do Pará mostrou os seguintes resultados em relação ao isolado 73442/PA/99 e ao protótipo BrCr: 207 indivíduos (53,2%) tinham anticorpos neutralizantes para ambos os vírus, 167 (42,9%) não tinham anticorpos e 15 tinham anticorpos para um dos dois vírus. Somente 20,2% das crianças com idade de 0 a 3 anos tinham anticorpos neutralizantes para EV-71, indicando que essas crianças estavam mais suscetíveis à infecção. Tanto o estudo de soroprevalência quanto o de sequenciamento da VP1 foram importantes para demonstrar a propagação e o padrão molecular do EV-71 circulante na região norte do Brasil

    Salt reduction in different bread types: an intervention study in the Northern Portugal

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    O pão é um dos alimentos mais antigos e consumidos em todo o Mundo, sendo considerado uma boa fonte de diversos nutrientes fundamentais para o desenvolvimento e saúde do organismo. Os dados do Inquérito Alimentar Nacional e de Atividade Física IAN-AF (2015/2016), em Portugal, identificam o pão como sendo considerado um dos principais alimentos a contribuir para a ingestão de sal dos portugueses. A Sociedade Portuguesa de Hipertensão, em colaboração com a Associação dos Industriais de Panificação, Pastelaria e Similares do Norte e o Instituto Nacional de Saúde Doutor Ricardo Jorge, desenvolveram um estudo interventivo com vista a reduzir o teor de sal no pão sem alterar as suas propriedades organoléticas. O objetivo deste estudo foi avaliar o teor de sal em 4 tipos de pão tradicional: carcaça, regueifa, broa e pão da avó, antes e depois da intervenção planeada. Antes da intervenção verificou-se que os valores de teor de sal encontrados, em todos os tipos de pão analisados, estavam abaixo de 1,4 g de sal por 100 g de pão (valor estabelecido pelo Decreto- -Lei n.º 75/2009, de 12 de agosto) e que, após intervenção, foi possível reduzir para valores entre 0,96 e 1,1 g de sal por 100 g de pão, sem alterar as características organoléticas. O estudo realizado demonstrou ser possível a redução do teor de sal no pão, sem alterações adicionais no processo de produção, constituindo uma medida de baixo custo que permite a melhoria da saúde pública, relativamente à prevenção de doenças crónicas associadas ao consumo excessivo de sal.Bread is a key staple in the Portuguese diet and provides many of the nutrients required for normal development and good health. The National Food and Physical Activity Survey IAN-AF (2015/2016), in Portugal, identify bread as one of the main foods contributing to Portuguese salt intake. The Portuguese Society of Hypertension, in collaboration with the Portuguese Bakeries Association from North and the National Institute of Health Dr. Ricardo Jorge, planned an intervention study to reduce the content of salt in the bread, without changing its organoleptic properties. The objective of this study was to evaluate the salt content in four types of traditional bread: “carcaça”, “regueifa”, “broa” e “pão da avó”, before and after the planned intervention. It was found that the values of salt content before the intervention were below the value established in legislation nº 75/2009 of 1.4 g of salt per 100 g of bread and that, after intervention it was possible to reduce the salt content to values between 0.96 and 1.1 g of salt per 100 g of bread, without changing the organoleptic characteristics. The study showed that it is possible to reduce the salt content in bread without additional changes in the production process, and it is a low-cost measure allowing the improvement of public health in relation to the prevention of chronic diseases associated with excessive salt consumptioninfo:eu-repo/semantics/publishedVersio

    Experimental and computational study of the energetics of hydantoin and 2-thiohydantoin

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    This work reports an experimental and a theoretical study of two imidazolidine derivatives, hydantoin (CAS No. 461-72-3) and 2-thiohydantoin (CAS No. 503-87-7). The standard (p degrees = 0.1 MPa) molar energies of combustion of hydantoin and 2-thiohydantoin were measured by static and rotating bomb combustion calorimetry, respectively. The standard molar enthalpies of sublimation, at T = 298.15 K, were derived from the temperature dependence of the vapour pressures of these compounds, measured by the Knudsen-effusion technique, and from high temperature Calvet microcalorimetry. The conjugation of these experimental results enables the calculation of the standard molar enthalpies of formation in the gaseous state, at T = 298.15 K, which are discussed in terms of structural contributions. We have also estimated the gas-phase enthalpy of formation from high-level ab initio molecular orbital calculations at the G3MP2B3 level of theory, being the computed values in good agreement with the experimental ones. Furthermore, this composite approach was also used to obtain information about the gas-phase basicities, proton and electron affinities and adiabatic ionization enthalpies

    In situ hydration imaging study of a ye'elimite paste by ptychographic x-ray computed tomography

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    Eco-cements are a desirable alternative to ordinary Portland cements because of their lower CO2 footprints. For instance, the manufacture of Calcium SulfoAluminate (CSA) cements is more environmentally friendly than that of Portland cements as their production may decrease CO2 footprint by up to 40%. CSA cements contain ye'elimite, Ca4Al6O12SO4, as main phase. The hydration of ye'elimite leads to hydrated compounds such as crystalline ettringite (AFt), crystalline monosulfoaluminate (AFm) and amorphous aluminum hydroxide gel, Al(OH)3·nH2O. Here, we report the results of a ptychographic X-ray computed tomography (PXCT) study on the in situ hydration of ye'elimite with gypsum at different early ages. PXCT is a nondestructive X-ray imaging technique which provides 3D electron density and attenuation coefficient distributions of cement pastes with an isotropic resolution close to 100 nm allowing distinguishing between component phases with very similar contrast in more conventional absorption-based X-ray tomography. The sample was prepared by hydrating ye'elimite with gypsum. Four datasets were recorded at 48, 53, 58 and 63 hours of hydration. The main aim of this imaging study was to quantify the microstructure evolution, within this time interval, with submicrometer spatial resolution. The different component phases were identified and their mass densities determined. Furthermore, the tomograms were segmented and the volume percentage of each component were determined and compared at the four hydrating ages. The overall porosity content (air and pore solution) decreased from 11.5 to 8.8 vol% and the anhydrous material content (ye'elimite and gypsum) decreased from 14.7 to 7.5 vol% in the studied time interval. Correspondingly, the hydrated content (crystalline ettringite and aluminum hydroxide gel) increased from 73.7 to 83.7 vol%. The time evolution of several anhydrous particles was analyzed to determine the dissolution rate of the ye'elimite particles. Similarly, the pore filling process has also been investigated by quantifying their time evolution. These rates are reported and some insights about the mechanisms of these processes are discussed.This work has been supported by MINECO through BIA2014−57658-C2-1-R and BIA2014-57658-C2-2-R, which is cofunded by FEDER, research grants. We thank SLS for providing beamtime at the cSAXS beamline. We also thank the Swiss National Science Foundation SNF for the support to the work of J.C.d.S. (Grant 137772). Instrumentation development was supported by SNF (R’EQUIP, No. 145056,“OMNY”) and the Competence Centre for Materials Science and Technology (CCMX) of the ETH-Board, Switzerland. In addition, the authors would like to thank Dr. Manuel Guizar-Sicairos for his valuable assistance with the ptychography and PXCT data analysis

    Hydration studies of ye’elimite by using Ptychographic X-ray nano-tomography

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    CSA (Calcium SulfoAluminate) cements may have variable compositions but all of them contain ye’elimite(Ca4Al6O12SO4). The manufacture of CSA cements is more environmentally friendly than that of ordinary Portland cements as their production releases up to 40% less CO2. The hydration of ye’elimite leads to crystalline ettringite (AFt) and amorphous aluminum hydroxide (AH3•nH2O). Ptychographic X-ray computed nanotomography (PXCT) has been used here to study the hydration of ye’elimite-containing samples. PXCT is an X-ray imaging technique having demonstrated an isotropic 3D resolution better than 20 nm[1]. PXCT, which nondestructively provides 3D images of the sample complex-valued X-ray refractive index, has been recently applied for hydration studies of Portland cement samples[2]. Samples for this study were measured in cSAXS beamline (Swiss Light Source). The main goal of this study has been the quantification of the electron and mass densities of the phases present in these samples. These mass densities were compared with the theoretical values in order to identify the phases and matched well the expected values. For instance, the hydration of pure ye’elimite with gypsum sample was studied. This sample should show a large amount of AFt due to the presence of gypsum in the hydration medium. This is precisely what it was observed from the analysis of the histogram. Figure 1 shows the tomogram of one slice obtained for this sample. The most relevant results for CSA cement hydration will be discussed. A volume of interest (VOI) histogram has been studied in order to identify all the phases. Figure 2 shows a comparison between the histogram obtained in this study and a previous one performed by Gastaldi et al. (2012) at TOMCAT Beamline (Swiss Light Source). As it can be observed, TOMCAT data cannot properly distinguish between AFt and ye'elimite phase. Conversely, PXCT technique can resolve the peaks for all the phases present in CSA cements. All reconstructions have been successful and now we are analyzing the data (segmentation, etc.) to characterize the porosities and the shape and size of the different phase, chiefly ettringite.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    The MOVE.TE Falls Prevention and Management Program: lessons learnt in the Portuguese context

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    MOVE.TE is a non-profit participatory physiotherapy platform that aims at translating knowledge in the field of physiotherapy and developing freely available evidence-based physiotherapy programmes targeting the primary care services of the Portuguese National Health service. A group of volunteer academics and clinicians collaborated at different stages and time points to create the first ever falls prevention and management programme and guidance for Physiotherapy in primary care, in Portugal. This report describes this seven-step process. In spite of many challenges, this project constitutes an example of advocacy in physiotherapy for the promotion of better healthcare for older adults.info:eu-repo/semantics/publishedVersio

    Effect of cerium-containing hydroxyapatite in bone repair in female rats with osteoporosis induced by ovariectomy

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    Osteoporosis is a public health problem, with bone loss being the main consequence. Hydroxyapatite (HA) has been largely used as a bioceramic to stimulate bone growth. In our work, a cerium-containing HA (Ce-HA) has been proposed and its effects on the antimicrobial and bone-inducing properties were investigated. The synthesis of the materials occurred by the suspension–precipitation method (SPM). The XRD (X-ray Diffraction) confirmed the crystalline phase, and the Rietveld refinement confirmed the crystallization of HA and Ce-HA in a hexagonal crystal structure in agreement with ICSD n◦ 26205. Characterizations by FT-IR (Fourier Transform Infrared Spectroscopy), XPS (X-ray Photoemission Spectroscopy), and FESEM-EDS (Field Emission Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy) confirmed the presence of cerium (Ce3+ and Ce4+ ). The antibacterial activity of Has was evaluated against Staphylococcus aureus 25,923 and Escherichia coli 25,922 strains, which revealed that the material has antimicrobial properties and the cytotoxicity assay indicated that Ce-containing HA was classified as non-toxic. The effects of Ce-HA on bone repair, after application in bone defects in the tibia of female rats with osteoporosis induced by ovariectomy (OVX), were evaluated. After 15 and 30 days of implantation, the samples were analyzed by Raman, histology and X-ray microtomography. The results showed that the animals that had the induced bone defects filled with the Ce-HA materials had more expressive bone neoformation than the control group.info:eu-repo/semantics/publishedVersio
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