ESTG - Artigos em revistas internacionais
URI permanente para esta coleção:
Navegar
Entradas recentes
- Nanofibrillated cellulose originated from Rhododendron ponticum to produce scaffolds using 3D printing for biomedical applicationsPublication . Lima, Tielidy A. de M. de; Lima, Gabriel Goetten de; Munir, Nimra; Coutinho, Joana Raquel Teixeira; Mitchell, Geoffrey Robert; Magalhães, Washington L. E.; Nugent, Michael J. D.Rhododendron ponticum is an invasive species that spreads rapidly and is described as one of the biggest threats to peatlands in Ireland. This study offers an innovative approach to utilizing Rhododendron waste. Initially, sawdust was submitted to a bleaching treatment and the nanofibrillated cellulose (NFC) was obtained using two different methods: ultra-fine friction grinding and twin-screw extrusion with the assistance of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) pre-treatment. The samples processed through twin-screw extrusion exhibited the presence of NFC at five intervals, as confirmed by TEM analysis. However, these samples displayed a higher diameter deviation compared to those processed through grinding alone. Notably, after 20 extrusion steps, the NFC diameter became more uniform, reaching approximately 35 nm. Sedimentation tests showed that extrusion produced more homogeneous cellulose size than the grinder method. However, FTIR characterization for the samples showed a unique band related to C-O-C glycosidic linkage. The results showed that grinding breaks these groups resulting in crystallinity values lower than extrusion, 50 % compared 60 %. Therefore, NFC with 20 steps by grinding was blended with polycaprolactone to produce a 3D scaffold using a 3D printer at different ratios of 1–5 % addition. The effect of 1 % of NFC was unique showing significant enhanced mechanical properties compared to pure polycaprolactone (PCL), additionally, the NFC does not exhibit toxicity so these materials show promise for biomedical applications.
- The role of institutional elements on strategic activities of small business practitionersPublication . Marietto, Marcio Luiz; Serra, Fernando Antônio RibeiroThis study offers different perspectives for observing the phenomenon of strategic practice of managers and sales persons in small stores located in an organisational field through the lens of strategy as practice (S-as-P) and institutional theory. Qualitative participant observation procedures were used in the largest Latin-American cluster of bridal stores and involved strategic work using the institutional elements of weddings. The results indicated that the institutional and dynamic elements of the symbolic ritual of wedding enable the interaction among practitioners in their strategic activities. This provides legitimacy and, consequently, the survival of the organisations. We present a model in which the propositions seek to direct future studies of S-as-P with the assumptions of institutional theory. The study also contributes analysing strategic activities of small business practitioners to increase the potential for future empirical researches.
- Set-Membership Position Estimation With GNSS Pseudorange Error Mitigation Using Lane-Boundary MeasurementsPublication . Bento, Luis Conde; Bonnifait, Philippe; Nunes, Urbano J.Model-based positioning methods involve nonlinear equations as is the case when using satellite pseudoranges on global navigation satellite systems (GNSSs) and local measurements on road features. As these are nonlinear models, classical estimation methods cannot provide guaranteed position estimation and can converge to local optima, sometimes far away from the global optimum or the true value. Based on interval analysis, set inversion, and constraints propagation on real values provide a framework that guarantees to find the true position with a characterized confidence domain. This paper describes an error bounded set membership algorithm that computes the absolute position of a road vehicle by using raw GNNS pseudoranges, lane boundary measurements, and a 2D road network map as geometric constraints. The algorithm is based on set inversion using interval analysis, and bounds are set on the measurements by taking into account a chosen risk. The GNSS pseudoranges errors are modeled carefully, and road constraints are formalized to provide additional information in the data fusion process. The proposed algorithm, named lane boundary augmented set-membership GNSS positioning (LB-ASGP), provides a novel and inexpensive approach to improve position estimation performance for road vehicles guaranteeing the enclosure of the computed solution with high confidence. Results from simulations and field experiments show that the LB-ASGP significantly reduces GNSS errors in the direction perpendicular to the lane thanks to the lane boundary measurements.
- Current Strategies to Produce 3D Electrospun-Based Wound Dressings for Skin RegenerationPublication . Ferreira, Carolina A. M.; Lemos, Marco F. L.; Maurício, Ana Colette; Dias, Juliana R.Tissue engineering-based wound dressings are a promising treatment approach that mimics the native skin microenvironment to promote effective healing and tissue regeneration. In fact, those advanced wound dressings can be made by electrospinning which has revolutionized the field of wound healing by developing biostructures that closely mimic the skin’s extracellular matrix (ECM). To date, most electrospinning research has focused on composition and materials rather than exploring advanced deposition strategies. Conventional electrospinning using random, aligned fibers, co-electrospinning, core-shell approaches, or redesigned collectors has achieved significant results in wound healing, which are discussed in this article. However, these approaches lack the development of realistic 3D structures. To achieve that, advancing approaches through the combination of electrospinning with different techniques such as gas foaming, short nanofiber assembly, or 3D printing significantly enhance skin regeneration of deep wounds (full-thickness and chronic wounds) compared to 2D structures. This review highlights the latest developments, design principles, and recent breakthroughs in electrospinning structures for skin regeneration and provides a fresh perspective for upcoming research in the field of 3D electrospun-based structures.
- Magnesium oxide coatings on thermoplastic polyurethane as a key approach to prevent catheter-associated infectionsPublication . Padrão, Tatiana; Monteiro, Fernando J.; Sousa, Susana R.; Dias, Juliana R.Central venous catheters (CVCs) are essential healthcare tools, but their use is often complicated by bacterial colonization on the catheter surface, leading to serious infections and life-threatening bloodstream complications. Current strategies, often reliant on antibiotics or antiseptics, are increasingly ineffective due to the rise of antimicrobial resistance. This study aimed to develop a novel antibacterial coating for CVCs by incorporating magnesium oxide (MgO) nanoparticles onto a thermoplastic polyurethane (TPU) film surface containing barium sulfate (BaSO4). The antibacterial efficacy of these coatings was evaluated against Staphylococcus epidermidis, a major pathogen in catheter-associated infections. The results showed that MgO coatings significantly inhibited bacterial growth in a concentration-dependent manner, with 0.50 % and 1.0 % MgO concentrations achieving complete eradication of both planktonic and adherent bacteria. Importantly, the coatings exhibited excellent cytocompatibility with fibroblasts and showed no significant impact on hemolysis or blood clotting. The 0.50 % MgO coating was identified as the optimal formulation, offering the best balance of potent antibacterial activity, cytocompatibility and hemocompatibility. This approach preserves the valuable physical and chemical properties of the TPU material while providing effective antibacterial protection. The straightforward and cost-effective coating process holds significant promise for industrial scale production, paving the way for a new generation of safer and more effective CVCs.
- Expanding the Potential of Self-Assembled Silk Fibroin as Aerogel Particles for Tissue RegenerationPublication . Bernardes, Beatriz G.; Baptista-Silva, Sara; Illanes-Bordomás, Carlos; Magalhães, Rui; Dias, Juliana Rosa; Alves, Nuno M. F.; Costa, Raquel; García-González, Carlos A.; Oliveira, Ana LeiteA newly produced silk fibroin (SF) aerogel particulate system using a supercritical carbon dioxide (scCO2)-assisted drying technology is herein proposed for biomedical applications. Different concentrations of silk fibroin (3%, 5%, and 7% (w/v)) were explored to investigate the potential of this technology to produce size- and porosity-controlled particles. Laser diffraction, helium pycnometry, nitrogen adsorption–desorption analysis and Fourier Transform Infrared with Attenuated Total Reflectance (FTIR-ATR) spectroscopy were performed to characterize the physicochemical properties of the material. The enzymatic degradation profile of the SF aerogel particles was evaluated by immersion in protease XIV solution, and the biological properties by cell viability and cell proliferation assays. The obtained aerogel particles were mesoporous with high and concentration dependent specific surface area (203–326 m2/g). They displayed significant antioxidant activity and sustained degradation in the presence of protease XIV enzyme. The in vitro assessment using human dermal fibroblasts (HDF) confirm the particles’ biocompatibility, as well as the enhancement in cell viability and proliferation.
- Phase-specific force–time adaptations in basketball jump shots under environmental constraintsPublication . Amaro, Catarina M.; Mendes, Rui; Castro, Maria António; Rice, Hannah; Gomes, Beatriz B.This study examined whether task-related and environmental constraints influence the vertical ground reaction force (vGRF) waveform during the basketball jump shot, with a focus on phase-specific adaptations across shooting positions. Eighteen senior basketball players performed jump shots from three shooting positions (45° right, middle, 45° left) under three conditions: baseline, simulated defensive opposition, and simulated gym audience noise. vGRF signals were recorded using a force platform and time-normalized to 0–100% of the movement cycle. One-dimensional Statistical Parametric Mapping (SPM) was applied using a hierarchical region-of-interest (ROI) approach, focusing on the unweighting, braking, and propulsive phases. Group-level effects were tested using a two-way SPM{F} ANOVA (Constraint × Position). Exploratory intra-individual SPM{t} analyses were conducted to examine athlete-specific adaptations. No significant main effects of constraint or position, and no constraint × position interactions were observed at the group level in any ROI (α = 0.05). Exploratory intra-individual analyses revealed heterogeneous, athlete-specific adaptations to external constraints and shooting position, predominantly during the braking and propulsive phases, with substantial variability in the timing and presence of significant clusters across athletes. The results indicate that experienced basketball players preserve a stable force–time organization during the jump shot despite environmental and task-related constraints. While group-level mechanical patterns remain invariant, individual athletes may exhibit phase-specific adaptations that do not generalize across the population. These findings underscore the importance of hierarchical and individualized analytical approaches for understanding skilled performance and support the use of ROI-based SPM for the biomechanical analysis of complex movement tasks.
- EMG Activity of the Biceps and Triceps Brachii During Basketball Chest Pass and Reception: Group Differences Based on Age, Experience, and Limb DominancePublication . Amaro, Catarina M.; Castro, Maria António; Amaro, Ana M.Understanding muscle activation patterns during sport-specific skills is essential for optimizing performance and training strategies. In basketball, upper limb actions such as passing and receiving require precise coordination and effective neuromuscular control. The main goal of this study was to analyze and compare the muscle activity of the biceps brachii and triceps brachii during the execution and reception of the two-handed chest pass in basketball players with different levels of competitive experience. Surface electromyography (EMG) data were collected from 14 federated athletes, aged between 11 and 29 years, using the BioSignal Plux system. Participants were allocated into two groups according to their playing experience. Muscle activation was analysed in terms of activation time (AT) and percentage of muscle activation (%MA), normalised to maximum voluntary contraction (MVC). A linear mixed model was used to evaluate the effects of experience level, limb dominance, and their interaction while accounting for repeated measures within participants. No significant differences were observed between dominant and non-dominant limbs for any variable. Significant differences between experience/ age groups were identified mainly in the triceps brachii, particularly for activation time in the lateral head and %MA in the long head. In general, more experienced/aged athletes demonstrated higher levels of neuromuscular activation and shorter activation times, suggesting different motor control strategies. A significant positive association was found between years of practice and %MA of the long head of the triceps brachii. These findings provide novel insights into neuromuscular recruitment during both the execution and reception phases of the basketball chest pass and may inform training strategies aimed at enhancing technical efficiency across developmental stages.
- Towards Improving Business Processes based on preconfigured KPI target values, Process Mining and Redesign PatternsPublication . Cherni, Jihen; Martinho, Ricardo; Ghannouchi, Sonia AyachiThe Business Process Management (BPM) lifecycle includes a redesign phase, which is an important step for stakeholders while working on the improvement of their Business Processes. Some research approaches on process improvement involve Key Performance Indicators and Process Mining, but essentially using the latter to verify if improvement efforts have been successful. In this paper, we propose a different approach for process improvement by first defining and configuring, process KPI target values, and second using Process Mining techniques to discover and analyze deviations from those values. Then, for each deviation we propose improvement solutions based on Business Process redesign patterns. Since this encompasses also an improvement cycle, we present our approach as an extension of the well-known BPM cycle. With this approach, process stakeholders will be able to quickly identify process KPI deviations based on quality, cost, time and flexibility, and resolve them by automatically applying proven redesign patterns.
- Challenges on the usability of digital platforms for informal caregivers and health professionals: the case study of Help2CarePublication . Ferreira Caroço, João Eduardo; Marques Gomes, Nuno Miguel; Martinho, Ricardo; Rijo, Rui; Peralta, Teresa; Carvalho, Daniel; Querido, Ana; Dixe, Maria dos AnjosThe usability of digital platforms assumes an important role in the support of health business processes. This is particularly relevant when these platforms automate previously manually-executed activities in a certain process, with the purpose of bringing time, cost and quality benefits both to end-users and health professionals. This is the main objective of the Help2Care e-Health digital platform, where informal caregivers can use a mobile app to access digital training materials on how to properly take care of their patients. Health professionals can, in turn, suggest these materials to their caregivers through a web application, communicate directly with them through a messaging system, and even perform remote health assessment and monitoring. However, the informal caregiver population presents specific attributes which, in general, require special attention for usability. Health professionals can also be challenged by such platforms and their inherent complexity. In this paper, we report the results and challenges of the usability studies performed on both mobile and web applications of the Help2Care platform.