275 research outputs found

    Variscan overthrusting, fluid flow and the genesis of magnetite ore-bodies at Azenhas area (Pedrógão, Ossa-Morena Zone, SE Portugal)

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    In the Azenhas area (SE Portugal), an important segment of a regional WNW-ESE Variscan thrust can be observed. The hanging wall felsic metavolcanics carried from ENE are evolved rhyolite tuffs. The underlying sequence is mainly composed of variably metasomatised allochthonous amphibolites that are believed to represent an ophiolite slice tectonically overlying the autochthonous Moura-Ficalho Complex. Within this latter sequence, numerous WNW-ESE thrusts with prevailing displacement towards W-SW cut prior sub-parallel structures with northwards thrust shear. According to the observed crosscutting relationships and to the available petrographic data, the metasomatism experienced by the lower amphibolite sequence took place mainly before the emplacement of the upper slices of amphibolites, preceding therefore the installation of the felsic metatuffs. Magnetite ore-bodies are found within strongly metasomatised amphibolites immediately below the major WNW-ESE thrust zone or its subsidiary thrust structures. Their genesis is envisaged as a result of a complex chemical reaction path that involves the ascent of aqueous oxidising fluids under a reverse temperature gradient generated during the tectonic emplacement of amphibolites. In order to test the geological plausibility of the thermal evolution and the time span needed for ore genesis a one-dimensional numerical model was developed. This model enables the tracing of vertical thermal profiles at different times and accounts for the thrust emplacement history, incorporating variable erosion rates of the rock sequence. The results obtained show that an inverted thermal gradient in the thrusted sequence is kept for over 1 Ma and a regular temperature increase (from 400ºC to 500ºC) is observed in the underlying rocks lasting for 4.5 to 5.5 Ma.info:eu-repo/semantics/publishedVersio

    Geodynamic evolution of the South Variscan Iberian Suture as recorded by mineral transformations

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    New structural, petrographic, mineralogical and geochemical data from the Beja-Acebuches Ophiolite Complex (BAOC) are presented, and reviewed together with data published elsewhere. The new data obtained shed light on questions such as: 1) the relative importance of the obduction event; 2) its geological record in the deep levels of BAOC; 3) the nature and intensity of the Variscan metamorphism and deformation during subsequent continental (arc) collision; 4) the age relationships between BAOC and the Beja Igneous Complex; and 5) by means of numerical modelling, the thermal metamorphism of the Ossa-Morena autochthonous terranes induced by the ophiolite obduction. The emerging picture is that of a fairly simple overall geological evolution for BAOC, seamlessly integrated within the evolution of the southern branch of the Iberian Variscides. Obduction of BAOC is a relatively minor early event in the general NE–SW convergence that gave rise to the orogen as seen regionally and is recorded by an anisotropic, high-temperature, metamorphic fabric at the gabbro levels and by subtle features of the chemical composition of primary minerals at the underlying peridotite level; it caused chilling of the obducted ophiolitic slab and no significant metamorphism on the autochtonous rocks of the Ossa-Morena Zone. BAOC underwent most of its deformation and (amphibolite facies) metamorphism during a later collisional event, that took place as the most primitive rocks of the Beja Igneous complex were being intruded, and whose waning stages are responsible for extensive serpentinisation of peridotites and for important aquocarbonic fluid discharges along the semibrittle–brittle shear zones meanwhile developed.info:eu-repo/semantics/publishedVersio

    Prevalence of major and minor electrocardiographic abnormalities and their relationship with cardiovascular risk factors in Angolans

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    Aims: To identify the prevalence of major and minor electrocardiographic abnormalities and their association with the main risk factors for cardiovascular disease in a population in the province of Bengo, northern Angola. Methods: A cross-sectional community-based study was conducted and a representative random sample stratified by sex and age was selected. In total, 2379 black individuals were included in the final analysis. A standard 12-lead ECG was recorded from all participants, analyzed and processed by the University of Glasgow software, and coded by the Minnesota code. Results: 22.3% of participants had minor electrocardiographic abnormalities and 4.58% major ECG abnormalities. The most common minor ECG abnormalities were abnormal T wave inversion, minor isolated ST abnormalities, and premature beats. The most common major ECG abnormalities were Left ventricular hypertrophy with major ST-T abnormalities, Ventricular conduction defects, and major Q-wave abnormalities. Hypertension, diabetes mellitus, hypercholesterolemia, alcohol consumption, and smoking, were significantly associated with major and minor electrocardiographic abnormalities. Conclusions: In this study, several participants had minor and major electrocardiographic abnormalities. Minor electrocardiographic abnormalities were more prevalent in men and major abnormalities in women. The electrocardiographic abnormalities had significant associations with the main cardiovascular risk factors.info:eu-repo/semantics/publishedVersio

    Design and development of mechatronic systems at UMinho: a review of some case studies

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    Mechatronics is an interdisciplinary area of engineering that combines mechanical engineering, electrical engineering and information technology. The development methodology for mechatronic systems supports the creation of innovative solutions, improving the reliability and ability of products and reducing their costs. This study reviews some projects (as case studies) that were undertaken by the authors in the area of mechatronics applied to the mechanical, textile, biotechnology and biomedical fields.info:eu-repo/semantics/publishedVersio

    Interpretation of gravity data to delineate structural features connected to low-temperature geothermal resources at Northeastern Portugal

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    A great number of low-temperature geothermal fields occur in Northern-Portugal related to fractured rocks. The most important superficial manifestations of these hydrothermal systems appear in pull-apart tectonic basins and are strongly conditioned by the orientation of the main fault systems in the region. This work presents the interpretation of gravity gradient maps and 3D inversion model produced from a regional gravity survey. The horizontal gradients reveal a complex fault system. The obtained 3D model of density contrast puts into evidence the main fault zone in the region and the depth distribution of the granitic bodies. Their relationship with the hydrothermal systems supports the conceptual models elaborated from hydrochemical and isotopic water analyses. This work emphasizes the importance of the role of the gravity method and analysis to better understand the connection between hydrothermal systems and the fractured rock pattern and surrounding geology. (c) 2013 Elsevier B.V. All rights reserved

    A systematic analysis of an industrial pickup and placement production system

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    Surface-mount technology is a method for producing electronic circuits in which the components are mounted or placed directly onto the surface of printed circuit boards. The purpose of this study was to analyze nozzle change in two production lines. Following a previous study, it was proposed that one type of nozzle would place resistors while another type of nozzle would place capacitors, contrary to what happened in the initial process, where the two placed both components. However, the change of nozzle was not done globally, but only applied to two specific types of capacitors that were more critical. Even so, the positive effect of this change was globally visible, both in the decreased number of component rejection and in the reduced number of component defects in the printed circuit boards. It was also possible to estimate the percentage saving and the expected growth from this new implementation. The data were validated using statistical analysis. Finally, the current cleaning periodicity of the nozzles was examined in order to verify if it was compromising their performance.- (undefined

    Mesenchymal Stromal Cell Secretome: Influencing Therapeutic Potential by Cellular Pre-conditioning

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    Mesenchymal stromal cells (MSCs) are self-renewing, culture-expandable adult stem cells that have been isolated from a variety of tissues, and possess multipotent differentiation capacity, immunomodulatory properties, and are relatively non-immunogenic. Due to this unique set of characteristics, these cells have attracted great interest in the field of regenerative medicine and have been shown to possess pronounced therapeutic potential in many different pathologies. MSCs' mode of action involves a strong paracrine component resulting from the high levels of bioactive molecules they secrete in response to the local microenvironment. For this reason, MSCs' secretome is currently being explored in several clinical contexts, either using MSC-conditioned media (CM) or purified MSC-derived extracellular vesicles (EVs) to modulate tissue response to a wide array of injuries. Rather than being a constant mixture of molecular factors, MSCs' secretome is known to be dependent on the diverse stimuli present in the microenvironment that MSCs encounter. As such, the composition of the MSCs' secretome can be modulated by preconditioning the MSCs during in vitro culture. This manuscript reviews the existent literature on how preconditioning of MSCs affects the therapeutic potential of their secretome, focusing on MSCs' immunomodulatory and regenerative features, thereby providing new insights for the therapeutic use of MSCs' secretome

    Stream sediment analysis for Lithium (Li) exploration in the Douro region (Portugal): A comparative study of the spatial interpolation and catchment basin approaches

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    Lithium (Li) was recently added to the list of critical raw materials by the European Union due to its significance for the green energy transition. Thus, the development of new toolchains to make Li exploration more economic and more effective is needed. Stream sediment analysis can play an important part in these new tool chains. In this work, two historical stream sediment datasets covering parts of the Fregeneda-Almendra pegmatite field in the Douro region (Portugal) were reprocessed considering two distinct approaches: spatial interpolation through inverse distance weighting (IDW) and the catchment basin approach using the concentration area (C-A) fractal analysis. The following objectives were delineated: (i) determine pathfinder elements for Li, considering relevant associations in the mineralization sources; (ii) compare the performance of both approaches; (iii) identify new target areas for Li. In the case of spatial interpolation, the highest Li values were associated to granites although the use of key elements allowed lithological discrimination and the delineation of target areas. In the catchment basin approach, fractal analysis proved to be effective in decreasing the number of areas of interest with high accuracy (>75%) when considering the previously mapped Li-pegmatites. One of the limitations identified was the number of anomalous basins related to the granites, despite the use of pathfinder elements allowing discriminating granite- from pegmatite-related Li anomalies. Comparing the two approaches, the spatial interpolation method is more adequate for the early stages of exploration (reconnaissance), while the catchment basin approach is more suited for prospect-scale exploration. Field validation of the results identified one pegmatite containing Li mineralization and three others with favorable signs for Li mineralization in the Douro region.The authors would like to thank the financial support provided by FCT– Fundação para a Ciência e a Tecnologia, I.P. (Portugal) and BMBF Jülich – Bundesministerium für Bildung und Forschung (Germany), with the ERA-MIN/0001/2017 – LIGHTS project. The work was also supported by Portuguese National Funds through the FCT projects UIDB/04683/2020 and UIDP/04683/2020 – ICT (Institute of Earth Sciences) and UIDB/50019/2020 – IDL (Instituto Dom Luiz). Joana Cardoso-Fernandes and Jéssica Lima are financially supported within the compass of their respective Ph.D. Thesis, ref. SFRH/BD/136108/2018 and ref. 2020.05793.BD, by national funds from MCTES through FCT, and co-financed by the European Social Fund (ESF) through POCH – Programa Operacional Capital Humano – and NORTE 2020 regional program. The Spanish Ministerio de Ciencia, Innovacion y Universidades (Project RTI2018-094097-B-100, with ERDF funds) and the University of the Basque Country (UPV/EHU) (grant GIU18/084) also contributed economically. The authors are also grateful to BRGM (Bureau de Recherches Géologiques et Minières) and LNEG (Laboratório Nacional de Energia e Geologia) for making the data available for this study

    Evaluation of Antipsychotic Drugs’ Stability in Oral Fluid Samples

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    Antipsychotics have narrow therapeutic windows, and their monitoring in biological fluids is therefore important; consequently, stability in those fluids must be investigated during method development and validation. This work evaluates the stability of chlorpromazine, levomepromazine, cyamemazine, clozapine, haloperidol, and quetiapine in oral fluid (OF) samples, using the dried saliva spots (DSS) sampling approach and gas chromatography coupled to tandem mass spectrometry. Since many parameters can influence the stability of the target analytes, design of experiments was adopted to check the crucial factors that affect that stability in a multivariate fashion. The studied parameters were the presence of preservatives at different concentrations, temperature, light, and time. It was possible to observe that antipsychotic stability improved when OF samples in DSS were stored at 4 °C, with a low ascorbic acid concentration, and in the absence of light. With these conditions, chlorpromazine and quetiapine were stable for 14 days, clozapine and haloperidol were stable for 28 days, levomepromazine remained stable for 44 days, and cyamemazine was stable for the entire monitored period (146 days). This is the first study that evaluates the stability of these antipsychotics in OF samples after application to DSS cards.info:eu-repo/semantics/publishedVersio

    Stability of Cocaine, Opiates, and Metabolites in Dried Saliva Spots

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    Funding: LA/P/0140/2020 (i4HB) being carried out by National Funds by Foundation for Science and Technology (FCT) and co-financed by community funds. T. Rosado thanks the Centre for Competences in Cloud Computing for the scholarship with reference C4_WP2.6_M1—Bioinformatics; UBIMEDICAL— CENTER-01-0145-FEDER-000019-C4—Centre for Competences in Cloud Computing, European Regional Development Fund (FEDER) and Centro Regional Operational Program (Centro 2020). S. Soares and J. Gonçalves acknowledge the FCT for the PhD fellowships with references SFRH BD/148753/2019. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Drug abuse still represents a global problem, and it is associated with an increased risk of diseases, injuries, and deaths. Cocaine (COC) and opiates are the most abused drugs and account for a significant number of fatalities. Therefore, it is important to develop methods capable of effectively identifying and quantifying these substances. The present study aims to evaluate the longterm stability of COC, ecgonine methylester (EME), benzoylecgonine (BEG), cocaethylene (COET), norcocaine (NCOC), morphine (MOR), codeine (COD) and 6-monoacetylmorphine (6-MAM) in oral fluid samples. The analytes of interest were isolated from the matrix (50 µL) using the dried saliva spots (DSS) sampling approach and were subsequently analyzed by gas chromatography coupled with tandem mass spectrometry (GC–MS/MS). The parameters that could influence the stability of the target compounds were studied, and these were storage temperature, light, use of preservatives (and respective concentrations), and time. The effects of each parameter were evaluated using the design of experiments (DOE) approach. The stability of the target analytes was improved when the DSS were stored at room temperature, in the presence of light and using 1% sodium fluoride. The best conditions were then adopted for the DSS storage and long-term stability was assessed. COD was only stable for 1 day, EME was stable for 3 days, COC, COET, NCOC and 6-MAM were stable for 7 days, MOR for 14 days and BEG remained stable throughout the study (136 days). This is the first study that evaluates the stability of these compounds in oral fluid samples after application in DSS cards, and optimizes the conditions in order to improve their stability.publishersversionpublishe
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