Biomarkers: a strategic tool in the assessment of environmental quality of coastal waters

Ecosystems are under the pressure of complex mixtures of contaminants whose effects are not always simple to assess. Biomarkers, acting as early warning signals of the presence of potentially toxic xenobiotics, are useful tools for assessing either exposure to, or the effects of these compounds providing information about the toxicant bioavailability. In fact, it has been argued that a full understanding of ecotoxicological processes must consider an integrated multi-level approach, in which molecular impact is related with higher-order biological consequences at the individual, population and community levels. Monitoring programs should make use of this tool to link contaminants and ecological responses fulfilling strategies like those launched by OSPAR (Commissions of Oslo and Paris) Convention on the protection of the marine environment of the North-East Atlantic and the International Council for the Exploration of the Sea (ICES). An overview of the work done in the past few years using biomarkers as in situ tools for pollution assessment in Portuguese coastal waters is presented as a contribution to the set up of a biomonitoring program for the Portuguese coastal zone. Considering the data set available the biomonitoring proposal should include the analysis of biomarkers and effects at individual levels. The aim of the program will include a spatial and temporal characterization of the biomarkers acetyl-cholinesterase, metallothioneins, DNA damage, adenylate energy charge and scope-for-growth levels. The investigation of the spatial variation of biomarkers is crucial to define sites for long term monitoring, which will be integrated with a chemical monitoring program. This framework will be a major contribution to the implementation of a national database for the use of biomarkers along the Portuguese coast.info:eu-repo/semantics/publishedVersio

Magnitudes y su medida en el currículo de educación primaria en España (1945-2013)

Presentamos un estudio comparativo del tratamiento establecido para la enseñanza y el aprendizaje de las magnitudes básicas y de su medida, según los diferentes currículos de matemáticas escolares vigentes en España para la educación primaria, entre 1945 y 2013. Consideramos los programas establecidos a partir de las cuatro leyes en vigor durante este período: la Ley de Educación Primaria (1945), la Ley General de Educación (Ministerio de Educación, 1970), la Ley de Ordenación General del Sistema Educativo (Ministerio de Educación y Ciencia, 1990) y la Ley Orgánica de Educación (Ministerio de Educación y Ciencia, 2006a). Los descriptores que consideramos para organizar y comparar los contenidos establecidos sobre magnitudes y su medida por los programas escolares derivados de estas cuatro leyes, proceden de los estándares del National Council of Teachers of Mathematics (NCTM) (1989). Mediante una selección y análisis de libros de texto publicados de acuerdo con los programas mencionados, estudiamos el tratamiento dado al metro como unidad principal de medida de longitud del Sistema Métrico Decimal y el reloj como instrumento para medir el tiempo. Resaltamos las particularidades de su tratamiento en estos libros de texto. Identificamos los cambios ocurridos y describimos la evolución del currículo relativa al trabajo con las magnitudes y su medida

Permanent deformation characterization of bituminous mixtures: laboratorial tests

In the last years some laboratorial tests are used to predict the permanent deformation behaviour of bituminous mixtures. Among those tests the Wheel Tracking test, the Cyclic Compression Test (Uniaxial and Triaxial) and the Repetitive Shear at Constant Height (RSCH) test, are considered for Portuguese practice. Also come out recently new European standards for those tests, with exception of the RSCH which is essentially used in the USA. Nevertheless some of testing conditions are not very well defined. Therefore, it is important to study the reliability and accuracy of each test in the task of predicting permanent deformation behaviour. In this work these test were used in the evaluation of a commonly used mixture in Portugal. Results show that all tests are suitable for predicting permanent deformation behaviour. Thus simpler and cheaper tests are more interesting to use.(undefined

The influence of temperature variation in the prediction of the pavement overlay life

This paper describes a study of the influence of temperature variation in the pavement overlay life, using finite-element methodology to consider the most predominant type of overlay distress observed in the field: reflective cracking. The temperature variation has a significant influence on thermally induced stresses that, in turn, affects the overlay predictive service life. This paper presents a three-dimensional (3D) finite element analysis to predict the pavement overlay life considering a combination of thermal pavement conditions with traffic loads in a pavement overlay modelled on a cracked pavement. The results present the influence of temperature variation in the cracked layer and overlay, as function of the initial pavement temperature. Furthermore, a comparison between the overlay life due to traffic loading and temperature variation in the overlay life is also presented. Finally, the overlay life was predicted using asphalt rubber and conventional mix fatigue laws allowing to conclude that asphalt rubber mixes exhibit more pavement life compared to conventional mixes even when the effects of temperature (temperature variation) are considered in the overlay design

Ensaios para deformação permanente em misturas betuminosas: comparação entre os resultados de wheel tracking e fluência dinâmica

A deformação permanente em misturas betuminosas é uma degradação de pavimentos rodoviários frequente mas para a qual ainda não existe uma metodologia que possa de forma cabal prever a sua evolução, nomeadamente para as camadas betuminosas. Para avaliar a susceptibilidade destas à deformação permanente existem vários ensaios laboratoriais, como sejam, o ensaio de Wheel Tracking e o de Fluência Dinâmica. Neste trabalho faz-se a comparação dos resultados obtidos para uma mistura betuminosa comum em Portugal com os ensaios laboratoriais de Wheel Tracking e de Fluência Dinâmica realizados, respectivamente, de acordo com a prEN 12697-22 e a prEN 12697-25. Foram ensaiados provetes produzidos em laboratório e recolhidos em obra. Os resultados obtidos confirmam a aplicabilidade dos ensaios e ainda que o parâmetro velocidade de deformação pode ser utilizado na caracterização do comportamento de misturas betuminosas à deformação permanente

Benefits of including hot mix recycled materials in pavement design

Pavement recycling is becoming more acceptable among the available techniques for pavement maintenance/rehabilitation. It is based on sustainable development, by reusing materials reclaimed from the pavements and reducing the disposal of asphalt materials. Based on the results obtained from laboratory tests carried out on two bituminous mixtures, one of which including 50% of recycled asphalt, some simulations were made for the design of a pavement where those mixtures would be used as a bituminous base. The aim of this investigation was to assess the benefits of using recycled materials, taking into account environmental and economical advantages. The results of pavement design were obtained using the linear elastic theory in BISAR (the structural analysis software developed by Shell). Fundamental properties of the mixtures analysed in this study were obtained from laboratory tests, which were carried out to determine their stiffness modulus and their resistance to fatigue and permanent deformation. With the results obtained from the pavement design, the cost savings of using recycled materials were quantified

Assessment of stiffness and fatigue tests in Portugal

In the last decade, quality control of asphalt mixtures for pavement construction on the main Portuguese national road network used, most of the time, four-point bending beam tests (4pb) results as a reference. Stiffness modulus and fatigue laws established with samples prepared in the laboratory are usually used as a reference for behaviour/quality control analysis of the samples coming from the construction site. There is however, with this procedure, not only a problem of real world representation but also a question of the compatibility of results coming, again most of the time, from different laboratories using different equipments. Trying to address the second problem, this paper presents the results obtained from four-point bending tests carried out in three different laboratories in Portugal, owning three different 4pb equip-ments, concerning the performance characterization of a typical Portuguese base course asphalt mixture. The paper finally discusses the variability of the results obtained and underlines the main inferences that could be extracted

Switching from a protease inhibitor-based regimen to a dolutegravir-based regimen : a randomized clinical trial to determine the effect on peripheral blood and ileum biopsies from antiretroviral therapy-suppressed human immunodeficiency virus-infected individuals

Background: Optimization of combination antiretroviral therapy (cART) can impact the human immunodeficiency virus (HIV) reservoir. We evaluated the effect on the HIV reservoir in peripheral blood and ileum biopsies in patients switching from boosted protease inhibitor (PI/r)-based therapy to dolutegravir (DTG)-based therapy. Methods: Impact of Integrase-inhibitor DOlutegravir On the viral Reservoir (INDOOR) is a phase 4 open-label clinical trial that randomly included 42 HIV type 1-infected individuals on effective cART: 20 who switched from PI/r-based to DTG-based cART (switch group), and 22 who remained in PI/r-based regimens (control group). We analyzed blood and ileum biopsies to quantify episomal, total, and integrated HIV DNA, cell-associated HIV RNA, residual plasma viremia, T-cell subsets, cell activation, and inflammation markers. Results: There were no related adverse events or treatment discontinuations due to drug intolerance. The HIV reservoir was consistently larger in ileal than in peripheral CD4(+) T cells in both groups (P <.01). Residual viremia in plasma decreased in the switch group (P =.03). However, we did not observe significant longitudinal changes in low-level viral replication, total and integrated HIV reservoir, HIV transcription, T-cell maturation subsets, immunoactivation markers, inflammatory soluble proteins, or cellular markers of latently infected cells. Conclusions: The INDOOR study is the first evaluation of changes in HIV reservoir size in ileum biopsies and in peripheral blood in individuals switched from PI/r- to DTG-based cART. Although this switch was safe and well tolerated, it had no impact on a large array of immunological and inflammatory markers or on HIV reservoir markers in peripheral or in ileal CD4(+) T cells

Lung myofibroblasts are characterized by down-regulated cyclooxygenase-2 and its main metabolite, prostaglandin E2.

Background: Prostaglandin E2 (PGE2), the main metabolite of cyclooxygenase (COX), is a well-known anti-fibrotic agent. Moreover, myofibroblasts expressing a-smooth muscle actin (a-SMA), fibroblast expansion and epithelial-mesenchymal transition (EMT) are critical to the pathogenesis of idiopathic pulmonary fibrosis (IPF). Our aim was to investigate the expression of COX-2 and PGE2 in human lung myofibroblasts and establish whether fibroblast-myofibroblast transition (FMT) and EMT are associated with COX-2 and PGE2 down-regulation. Methods: Fibroblasts obtained from IPF patients (n = 6) and patients undergoing spontaneous pneumothorax (control,n = 6) and alveolar epithelial cell line A549 were incubated with TGF-b1 and FMT and EMT markers were evaluated. COX-2 and a-SMA expression, PGE2 secretion and cell proliferation were measured after IL-1b and PGE2 incubation. Results: Myofibroblasts from both control and IPF fibroblast cultures stimulated with IL-1b showed no COX-2 expression. IPF fibroblasts showed increased myofibroblast population and reduced COX-2 expression in response to IL-1b. TGF-b1 increased the number of myofibroblasts in a time-dependent manner. In contrast, TGF-b1 induced slight COX-2 expression at 4 h (without increase in myofibroblasts) and 24 h, but not at 72 h. Both IPF and control cultures incubated with TGF-b1 for 72 h showed diminished COX-2 induction, PGE2 secretion and a-SMA expression after IL-1b addition. The latter decreased proliferation in fibroblasts but not in myofibroblasts. A549 cells incubated with TGF-b1 for 72 h showed downregulated COX-2 expression and low basal PGE2 secretion in response to IL-1b. Immuno-histochemical analysis of IPF lung tissue showed no COX-2 immuno-reactivity in myofibroblast foci. Conclusions: Myofibroblasts are associated with COX-2 down-regulation and reduced PGE2 production, which could be crucial in IPF development and progression