Browsing by Issue Date, starting with "2020-04"
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- Gender Differences in Students’ Assessment in a Fluid Mechanics CoursePublication . Sena-Esteves, Maria Teresa; Morais, Cristina; Ribeiro, Margarida; Pereira, Isabel; Guedes, Anabela; Soares, Filomena Baptista; Leao, Celina PintoThe main objective of the present work is to verify if, and in what extent, there is a correlation between gender and grades in a topic that is regarded as a core competence of chemical engineering. This analysis is based on data collected through a questionnaire concerning students’ perceptions. Besides no statistical difference on final student's marks, specific differences were obtained and discussed, namely concerning teaching methodologies.
- Mineral Composition of Subcritical Water Extracts of Saccorhiza Polyschides, a Brown Seaweed Used as Fertilizer in the North of PortugalPublication . Soares, Cristina; Švarc-Gajić, Jaroslava; Oliva-Teles, Maria Teresa; Pinto, Edgar; Nastić, Nataša; Savić, Saša; Almeida, Agostinho; Delerue-Matos, CristinaThe present work aimed at studying Saccorhiza polyschides extracts obtained by subcritical water extraction as a potential source of essential macro and trace elements, aiming for its potential application as a biofertilizer. The mineral composition, as well as sulfate, chlorine and iodine, total organic matter, and total nitrogen content, were determined on the extracts obtained from seaweeds harvested during low tide at the northern Portuguese coast. The selected parameters are important for a biofertilizer. Among the macronutrients, the most abundant was K (15.7 ± 0.2 g/L), followed by Na (5.46 ± 0.11 g/L), S (1.52 ± 0.06 g/L), Ca (1.09 ± 0.11 g/L), and Mg (1.02 ± 0.08 g/L). Several important micronutrients (Zn, B, Cl, P, Mo, V, Se, and I) have also been found in the extracts. The total organic matter was 34.1 ± 0.3 g/L. The extracts present low levels of toxic compounds such as Ni, Cd, and Pb. Considering the composition of the obtained extracts, these can find application in the development of fertilization products. The composition of subcritical water extracts of S. polyschides suggests that they may have important characteristics as a biofertilizer and can be an option in biofortification experiments with essential nutrients. The method can be easily scaled up which makes it attractive for agricultural applications.
- Insights on Ultrafiltration-Based Separation for the Purification and Quantification of Methotrexate in NanocarriersPublication . Marques, Sara S.; Ramos, Inês I.; Fernandes, Sara; Barreiros, Luisa; Lima, Sofia A. C.; Reis, Salette; Domingues, M. Rosário M.; Segundo, Marcela A.The evaluation of encapsulation efficiency is a regulatory requirement for the characterization of drug delivery systems. However, the difficulties in efficiently separating nanomedicines from the free drug may compromise the achievement of accurate determinations. Herein, ultrafiltration was exploited as a separative strategy towards the evaluation of methotrexate (MTX) encapsulation efficiency in nanostructured lipid carriers and polymeric nanoparticles. The effect of experimental conditions such as pH and the amount of surfactant present in the ultrafiltration media was addressed aiming at the selection of suitable conditions for the effective purification of nanocarriers. MTX-loaded nanoparticles were then submitted to ultrafiltration and the portions remaining in the upper compartment of the filtering device and in the ultrafiltrate were collected and analyzed by HPLC-UV using a reversed-phase (C18) monolithic column. A short centrifugation time (5 min) was suitable for establishing the amount of encapsulated MTX in nanostructured lipid carriers, based on the assumption that the free MTX concentration was the same in the upper compartment and in the ultrafiltrate. The defined conditions allowed the efficient separation of nanocarriers from the free drug, with recoveries of >85% even when nanoparticles were present in cell culture media and in pig skin surrogate from permeation assays.
- Effects of safety and health training in metalworking small-sized enterprisesPublication . Barrosa, Beatriz L.; Dores, Artemisa Rocha; Rodrigues, MatildeSafety and health training is an essential tool to reduce occupational accidents and diseases. However, the method applied is critical for the effect of a training programme in Occupational Safety & Health (OSH) related outcomes. Additionally, studies about the appropriateness of OSH training methods involving small-sized enterprises are scarce. This study aims to compare the effect of two training methods when applied in metalworking small-sized enterprises: an active method, with group discussion, and an expository method, with formal exposure. The effect of these two methods was assessed at the level of risk perception (perceptions of susceptibility, severity, barriers and benefits), safety behaviour (safety compliance and safety participation) and OSH knowledge. A sample of 212 workers was divided in three groups: one experimental group and two control groups (passive and active). In order to evaluate the effect of safety and health training in the different dependent variables, a questionnaire was applied before and one month after the training sessions. The results showed that safety and health training had a positive, but limited, effect on the variables under study. Significant differences were found between both moments for perception of susceptibility and OSH knowledge. However, no significant differences between both training methods after the intervention were observed in this study.
- Editorial for "Radiomics based on multimodal MRI for the differential diagnosis of benign and malignant breast lesions"Publication . Nogueira, Luisa; Nunes, R. G.Breast magnetic resonance imaging (MRI) is widely used to detect and characterize lesions, presenting good sensi- tivity but moderate specificity. To improve accuracy, new MRI sequences are continuously being sought. Diffusion- weighted imaging (DWI) probes the lesions’ cellularity, improving specificity. However, the distributions of the apparent diffusion coefficients (ADCs) for different lesion types show an overlap. Extensions to the monoexponential DWI model have thus been proposed such as diffusion- kurtosis imaging (DKI).
- Real-time Modeling of Abnormal Physiological Signals in a Phantom for Bioengineering EducationPublication . Vieira, Helder; Costa, Nelson; Coelho, Luis Filipe Pinto; Alves, JoaquimIn clinical practice and in particular in the diagnostic process, the assessment of cardiac and respiratory functions is supported by electrocardiogram and auscultation. These exams are non-invasive, quick and inexpensive to perform and easy to interpret. For these reasons, this type of assessment is a constant in the daily life of a clinician and the information obtained is central to the decision making process. Therefore, it is essential that during their training, students of health-related subjects acquire skills in the acquisition and evaluation of the referred physiological signals. Simulation, considering the technological possibilities of today, is an excellent preparation tool since it exposes trainees to near real contexts but without the associated risks. Hence, the simulation of physiological signals plays an important role in the education of healthcare professionals, bioengineering professionals and also in the development and calibration of medical devices. This paper describes a project to develop synchronized electrocardiogram (ECG), phonocardiogram (PCG) and breathing sounds simulators that aims to improve an existing phantom simulator. The developed system allows, in an integrated way, to generate normal and pathological signals, being contemplated several distinct pathologies. For engineering education, it is also possible to simulate the introduction of signal disturbances or hardware malfunctions. A graphical interface allows changing operating parameters in real time.
- A bibliometric analysis of 10 years of EDUCON (2010-2019)Publication . Costa, Alexandra R.; Alves, Gustavo R.; Moura, A.In this paper we present a bibliometrics analysis of the 10 editions of the Global Engineering Education Conference (EDUCON). EDUCON is a conference of the IEEE Education Society for region 8. It started in 2010 and since then it is organized annually. With this study we intend to analyze the growth of the conference, namely through the evolution of the number of submissions/publications, and the number of citations per article. We also intend to analyze the number of references per article. A descriptive statistics of these indicators is done along the paper. With an initial set of 10 editions, it will be possible to investigate the impact of future editions, by performing a sliding-frame analysis, i.e. replacing the oldest by the newest edition and analyzing how this impacts the presented charts.
- The acute effects of manual and instrument-assisted cervical spine manipulation on pressure pain threshold, Pressure pain perception, and muscle-related variables in asymptomatic subjects: a randomized controlled trialPublication . Nogueira, Nuno; Campelo, Natalia; Lopes, Ângela; Torres, Rui; Sousa, Andreia S. P.; Ribeiro, FernandoThe purpose of this study was to compare the immediate effects in asymptomatic participants of manual and instrument-assisted cervical manipulation on pressure pain thresholds, pressure pain perception, and muscle mechanical properties (tone, stiffness, and elasticity) over muscles anatomically related and unrelated to the manipulated level.
- Web Accessibility Assessment and Universal AccessPublication . P. Afonso, Ana
- Oxidative Stress Modulation and Radiosensitizing Effect of Quinoxaline-1,4-Dioxides DerivativesPublication . Silva, Liliana; Coelho, Pedro; Teixeira, Dulce; Monteiro, Armanda; Pinto, Gabriela; Soares, Raquel; Prudêncio, Cristina; Vieira, MónicaQuinoxaline-1,4-dioxide (QNX) derivatives are synthetic heterocyclic compounds with multiple biological and pharmacological effects. In this study, we investigated the oxidative status of quinoxaline-1,4-dioxides derivatives in modulating melanoma and glioma cell lines, based on previous results from the research group and their capability to promote cell damage by the production of Reactive Oxygen Species (ROS).