74 research outputs found

    Dietary sugars analysis: quantification of fructooligossacharides during fermentation by HPLC-RI method

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    In this work, a simple chromatographic method is proposed and in-house validated for the quantification of total and individual fructooligossacharides (e.g., 1-kestose, nystose, and 1F-fructofuranosylnystose). It was shown that a high-performance liquid chromatography with refractive index detector could be used to monitor the dynamic of fructooligossacharides production via sucrose fermentation using Aspergillus aculeatus. This analytical technique may be easily implemented at laboratorial or industrial scale for fructooligossacharides mass-production monitoring allowing also controlling the main substrate (sucrose) and the secondary by-products (glucose and fructose). The proposed chromatographic method had a satisfactory intra- and inter-day variability (in general, with a relative standard deviation lower than 5%), high sensitivity for each sugar (usually, with a relative error lower than 5%), and low detection (lower than 0.06 ± 0.04 g/L) and quantification (lower than 0.2 ± 0.1 g/L) limits. The correct quantification of fructooligossacharides in fermentative media may allow a more precise nutritional formulation of new functional foods, since it is reported that different fructooligossacharides exhibit different biological activities and effects.This work was partially co-financed by FCT and FEDER under Program COMPETE (Project PEst-C/EQB/LA0020/2013), by the Strategic Project PEst-OE/EQB/LA0023/2013 and by the project ref. RECI/BBB-EBI/0179/2012 (project number FCOMP 01-0124-FEDER-027462) funded by Fundação para a Ciência e a Tecnologia

    Personalized dynamic phantom of the right and left ventricles based on patient-specific anatomy for echocardiography studies — Preliminary results

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    Dynamic phantoms of the heart are becoming a reality, with their use spread across both medical and research fields. Their purpose is to mimic the cardiac anatomy, as well as its motion. This work aims to create a dynamic, ultrasound-compatible, realistic and flexible phantom of the left and right ventricles, with application in the diagnosis, planning, treatment and training in the cardiovascular field for studies using echocardiography. Here, we focus on its design and production with polyvinyl alcohol cryogel (PVA-C), to be assembled with a pump and an electromechanical (E/M) system in a water tank. Based on a patient-specific anatomical model and produced using a 3D printing technique and molding, the PVA-C phantom mimics the ventricles' natural anatomy and material properties, while the pump and E/M systems mimic the natural movements and pressures. The PVA-C phantom was assessed by imaging and measuring it using a four-dimensional ultrasound machine. The PVA-C phantom demonstrated to be a versatile option to produce patient-specific biventricular models, preserving their shape after manufacturing and presenting good echogenic properties. Both chambers were clearly seen in the ultrasound images, together with the interventricular septum and the myocardial wall. Automated left ventricle measures revealed a decrease of its volume with regard to the designed model (98 ml to 74 ml). Overall, the preliminary results are satisfactory and encourage its use for the abovementioned purposesFEDER funds through the Competitiveness Factors Operational Programme (COMPETE), and by National funds through the Foundation for Science and Technology (FCT) under the project POCI -01-0145-FEDER-007038 and EXPL/BBB-BMD/2473/2013, and by the projects NORTE-01-0145-FEDER-000013 and NORTE-01-0145-FEDER-024300, supported by the NORTE 2020, under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER). J. Gomes-Fonseca, P. Morais, S. Queirós, and F. Veloso were funded by FCT under the Ph.D. grants PD/BDE/113597/2015, SFRH/BD/95438/2013, SFRH/BD/93443/2013, and SFRH/BD/131545/2017info:eu-repo/semantics/publishedVersio

    Measurements of vibrations induced by high-speed trains

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    O presente artigo descreve as acções empreendidas no âmbito de um projecto de investigação em Portugal para realizar a medição das vibrações geradas pelo tráfego de comboios, em particular os comboios de alta velocidade. Neste contexto estão em curso campanhas de medição de vibrações com recurso a acelerómetros na Linha do Norte, onde são instrumentadas secções com diferentes características geométricas e geotécnicas. Para a campanha de testes preliminares, neste artigo são apresentados os aspectos relativos aos equipamentos usados, às dificuldades experimentais e ao processo de processamento e interpretação de resultados, ilustrando-se algumas das medições efectuadas. Os resultados das medições servirão também de suporte à calibração de modelos numéricos em desenvolvimento.The paper describes actions in the aim of a research project in Portugal to carried out measurements of train induced vibrations, particularly high speed trains. In this context, it is being performed a vibration measurement test campaign with accelerometers in the Linha do Norte, where sections with different geometric and geotechnical characteristics will be instrumented. For the preliminary test campaign, in this paper aspects related to equipment, to difficulties experimented and results processing and interpretation process are presented, being illustrated some measurements of vibrations that were performed. The measurements results will be used as support to calibrate numerical models in development.Universidade de Coimbra. Faculdade de Ciências e Tecnologia (FCT-UC)Fundação para a Ciência e a Tecnologia (FCT) - POCI/ECM/61114/200

    Assessment of 3D scanners for modeling Pectus Carinatum corrective bar

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    Pectus Carinatum (PC) is a chest deformity consisting on the anterior protrusion of the sternum and adjacent costal cartilages. Non-operative corrections, such as the orthotic compression brace, require previous information of the patient chest surface, to improve the overall brace fit. This paper focuses on the validation of the Kinect scanner for the modelling of an orthotic compression brace for the correction of Pectus Carinatum. To this extent, a phantom chest wall surface was acquired using two scanner systems - Kinect and Polhemus FastSCAN - and compared through CT. The results show a RMS error of 3.25mm between the CT data and the surface mesh from the Kinect sensor and 1.5mm from the FastSCAN sensor.The authors acknowledge to Foundation for Science and Technology (FCT) - Portugal for the fellowships with the references: UMINHO/BI/95/2012; SFRH/BD/68270/2010; SFRH/BD/74276/2010 and SFRH/BPD/46851/2008. This work was also supported by FCT R&D project PTDC/SAU-BEB/103368/2008

    A dual-modal CT/US kidney phantom model for image-guided percutaneous renal access

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    Percutaneous renal access (PRA) is a crucial step in some minimally invasive kidney interventions. During this step, the surgeon inserts a needle through the skin until the kidney target site using fluoroscopy and ultrasound imaging. Recently, new concepts of enhanced image-guided interventions have been introduced in these interventions. However, their validation remains a challenging task. Phantom models have been presented to solve such challenge, using realistic anatomies in a controlled environment. In this work, we evaluate the accuracy of a porcine kidney phantom for validation of novel dual-modal computed tomography (CT)/ultrasound (US) image-guided strategies for PRA. A porcine kidney was combined with a tissue mimicking material (TMM) and implanted fiducial markers (FM). While the TMM mimics the surrounding tissues, the FM are used to accurately assess the registration errors between the US and CT images, providing a valid ground-truth. US and CT image acquisitions of the phantom model were performed and the FM were manually selected on both images. A rigid alignment was performed between the selected FM, presenting a root-mean-square error of 1.1 mm. Moreover, the kidney was manually segmented, presenting volumes of 203 ml and 238 ml for CT and US, respectively. The initial results are promising on achieving a realistic kidney phantom model to develop new strategies for PRA, but further work to improve the manufacturing process and to introduce motion and anatomical artifacts in the phantom is still required.This work has been funded by FEDER funds, through the Competitiveness Factors Operational Programme (COMPETE), and by National funds, through the Foundation for Science and Technology (FCT), under the scope of the project NORTE-01-0145-FEDER-000013, supported by the NORTE 2020, under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER). J. Gomes-Fonseca, A. Miranda, P. Morais, and S. Queirós were funded by FCT under the Ph.D. grants PD/BDE/113597/2015, SFRH/BD/52059/ 2012, SFRH/BD/95438/2013, and SFRH/BD/93443/2013, respectively.info:eu-repo/semantics/publishedVersio

    WindS@UP: the e-science platform for windscanner.eu

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    The WindScanner e-Science platform architecture and the underlying premises are discussed. It is a collaborative platform that will provide a repository for experimental data and metadata. Additional data processing capabilities will be incorporated thus enabling in-situ data processing. Every resource in the platform is identified by a Uniform Resource Identifier (URI), enabling an unequivocally identification of the field(s) campaign(s) data sets and metadata associated with the data set or experience. This feature will allow the validation of field experiment results and conclusions as all managed resources will be linked. A centralised node (Hub) will aggregate the contributions of 6 to 8 local nodes from EC countries and will manage the access of 3 types of users: data-curator, data provider and researcher. This architecture was designed to ensure consistent and efficient research data access and preservation, and exploitation of new research opportunities provided by having this “Collaborative Data Infrastructure”. The prototype platform—WindS@UP—enables the usage of the platform by humans via a Web interface or by machines using an internal API (Application Programming Interface). Future work will improve the vocabulary (“application profile”) used to describe the resources managed by the platform.The WindScanner.eu|The European WindScanner Facility|is an ESFRI project (N: 312372) under the FP7-Infrastructures-2012-1. The authors are grateful to all colleagues in WP5 for the fruitful discussions, namely Dimitri Foussekis (CRES), Doron Callies (IWES Fraunhofer), Hans Verhoef (ECN), Harald Svendsen (Sintef), Jan Willem Wagenaar (ECN), Javier Sanz Rodrigo (CENER), Martin Bitter (Forwind), Mikael Sj oholm (DTU), Steen Arne S rensen (DTU) and Teresa Sim~oes (LNEG)

    Questions in Science textbooks: development and validation of a checklist

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    Questões são enunciadas que requerem uma resposta refletida e que desempenham diversas funções educativas, incluindo o despoletar novas aprendizagens. Neste caso, o seu uso enquadra-se na Aprendizagem Baseada na Resolução de Problemas (ABRP, do inglês, Problem-Based Learning, PBL), que coloca o aluno no centro dos processos de ensino e aprendizagem, atribuindo-lhe um papel ativo na aprendizagem de novo conhecimento. Atendendo à influência que os manuais exercem nas práticas de ensino, a questão que se coloca é a de saber em que medida as questões incluídas nos manuais escolares de Ciências podem fomentar um ensino orientado para a ABRP. Neste texto, descrever-se-á o processo de construção e validação de uma grelha de análise de questões incluídas em manuais escolares de Ciências com essa finalidade, apresentando-se não só essa grelha, mas também, a título ilustrativo, uma aplicação da mesma a um tópico de Ciências, 8º ano, abordado nas duas disciplinas desta área.Questions require a thoughtful answer and can play diverse educational roles, such as stimulating the learning of new knowledge, as is the case in Problem-Based Learning (PBL) contexts. In this context, the student is placed at the center of the teaching and learning processes and plays an active role in the learning of new knowledge. Bearing in mind the influence that textbooks exert on teaching practices, it is worthwhile questioning to which extent questions included in school science textbooks promote a PBL oriented teaching approach. This paper describes the development and validation of a checklist for analyzing the questions included in science textbooks. After introducing the checklist, an example of its application to a science unit assigned to two junior high school science courses (8th grade) is given, approaching the two disciplines in the area

    Porous PU/PEDOT:PSS electrodes for probing bioelectricity in Oscillatoria sp. Cohorts

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    Increasing frequency of poor water quality events associated with cyanobacteria strains capable of producing taste and odour (T&O) metabolites and toxins is a global concern for human health and the drinking water industry. This is mostly due to the inability of timely detecting and predicting cyanobacteria productivity associated with water quality risks. Here, we develop and characterize an ultra-sensitive electrophysiology system based on porous polyurethane (PU) foams coated with poly (3, 4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT: PSS) exploiting large-area electrodes of 199 cm2, which maximizes the double-layer capacitance and concomitant detection sensitivity. The measured signal of the cyanobacteria model taxa Oscillatoria sp. results from the sum of all individual cell contributions and scales with electrode area, hence indicating correlation with productivity and biomass. Stochastic activity across the cohort is monitored as uncorrelated noise. Yet, when Oscillatoria sp. operate cooperatively, the signal appears as intercellular Ca2+ waves which are benchmarked with a conventional fluorescent probe and suppressed with the specific ion channel inhibitor gadolinium chloride. We suggest the existence of a paracrine signaling mechanism with Ca2+ acting as the chemical messenger across large cohorts that may prove to be linked with T&O metabolite 2-Methylisoborneol (2-MIB) production. The technology proposed here would enable in-situ real time monitoring of benthic cyanobacteria productivity and hence proxy data for their metabolite production. This paves the way for identifying sources of cyanobacteria metabolites including 2-MIB, geosmin and cyanotoxins, and hence identify intervention solutions and treatment optimization for removal of these detrimental metabolites
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