ESTG - Artigos em revistas internacionais
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- A 2D Ray-Tracing Based Model for Micro- and Millimeter-Wave Propagation Through VegetationPublication . Leonor, Nuno R.; Caldeirinha, Rafael F. S.; Fernandes, Telmo R.; Ferreira, David; Sánchez, Manuel GarcíaA novel two dimensional model to characterize the electromagnetic behavior of trees has been developed with the purpose of being used in ray-tracing based simulation platforms. This model uses various point scatterers with specific radiation characteristics to describe the effect of the trees present in the radiowave propagation path. The method to extract the parameters of the point scatterers from measurements is presented. The performance of this novel formulation is assessed in a tree formation scenario against measurements results obtained in a controlled environment, inside an anechoic chamber, at 20 and 62.4 GHz. Additionally, a comparison analysis with a discretized radiative energy transfer (dRET) approach is conducted, where a relatively good agreement has been found. The absence of readily plug-in models considering propagation through and/or around vegetation makes this new tool interesting for radio planning purposes.
- Determinants of innovation capacity: Empirical evidence from services firmsPublication . Silva, Maria Jose Madeira; Simões, Jorge; Sousa, Gastão; Moreira, Jacinta; Mainardes, Emerson WagnerThis research aims to analyze the degree of importance of investment and expenditure on innovation activities for innovation capacity, in the scope of Portuguese services firms. The literature review considers three main approaches regarding service innovation: Assimilation, demarcation and synthesis. A conceptual model was proposed and several research hypotheses were empirically tested using secondary data, belonging to the 4th CIS 4, supervised by EUROSTAT. A data set from 1306 services firms was studied. The method used was the logistic regression model. According to the results obtained, the greater the financial investment in acquisition of machinery, equipment and software, in internal research and development, in acquisition of external knowledge, in marketing activities and other procedures, the greater the propensity for firms to innovate in terms of services. This study highlights the contributions that innovation activities can provide in what regards the development of innovation process, giving special emphasis to their service innovation.
- Dental Age Estimation based on Development Dental Atlas Assessment in a Child/Adolescent Population with Systemic DiseasesPublication . Pereira, Cristiana Palmela; Russell, Lucianna Maria; Fernandes, Maria de Pádua; Silva, Ricardo Henrique Alves da; Santos, Rui Filipe VargasBackground: Forensic estimation of chronological age has played an increasingly important role as part of cadaver identification, and also in living individuals due to the phenomenon of immigration and sexual abuse of undocumented trafficked children. Objective: This research aimed to validate the already used dental mineralization and eruption atlas in normal children and adolescent population in estimating chronological age in a young population, particularly those with special needs, majority of them with systemic diseases. Participants and Setting: A sample of 163 orthopantomograms from two independent medical institutions was collected from 133 patients aged between 4 and 23 years. Method: The orthopantomograms were divided into two groups, 95 from patients with systemic pathologies that have repercussions on dental development and 68 with systemic pathologies without dental repercussions. Dental ages were estimated by the London Atlas using the left side and then independently the right side of the maxilla. The intraobserver and interobserver agreements were evaluated. The difference between dental age estimates and the chronological age and its absolute value were calculated and analyzed.Results: Statistically significant differences were found between estimates and chronological age, revealing a general prevalence for underestimation; except for those under the age of 12. Nevertheless, the underestimation in individuals under the age of 16 was not significant (with an average of less than one month), while the underestimation was significant for persons who were at least 16 years old (with an average over 26 months). Furthermore, for those persons with systemic diseases with dental repercussions a greater error in underestimation was obtained, which indicates that the midpoint values should be reassessed in persons with Down’s syndrome, chromosomal alterations, syndromes and central nervous system disorders. Conclusions: This atlas can be potentially used as a tool for age estimation in a population with special needs and, also, in a population with systemic diseases, but we suggest further studies with larger international samples to create adequate atlases for all the required scenarios, mainly, diagrams for people with systemic diseases who are over the age of 16.
- MSCs Conditioned Media and Umbilical Cord Blood Plasma Metabolomics and CompositionPublication . Pereira, Tiago; Ivanova, Galya; Caseiro, Ana Rita; Barbosa, Paula; Bártolo, Paulo Jorge; Santos, José Domingos; Luís, Ana Lúcia; Maurício, Ana Colette; Ivanovic, ZoranHuman mesenchymal stem cells (hMSCs) from umbilical cord (UC) blood (UCB) and matrix are tested clinically for a variety of pathologies but in vitro expansion using culture media containing fetal bovine serum (FBS) is essential to achieve appropriate cell numbers for clinical use. Human UCB plasma (hUCBP) can be used as a supplement for hMSCs culture, since UCB is rich in soluble growth factors and due to worldwide increased number of cryopreserved UCB units in public and private banks, without the disadvantages listed for FBS. On the other hand, the culture media enriched in growth factors produced by these hMSCs in expansion (Conditioned medium - CM) can be an alternative to hMSCs application. The CM of the hMSCs from the UC might be a better therapeutic option compared to cell transplantation, as it can benefit from the local tissue response to the secreted molecules without the difficulties and complications associated to the engraftment of the allo- or xeno-transplanted cells. These facts drove us to know the detailed composition of the hUCBP and CM, by 1H-NMR and Multiplexing LASER Bead Technology. hUCBP is an adequate alternative for the FBS and the CM and hUCBP are important sources of growth factors, which can be used in MSCs-based therapies. Some of the major proliferative, chemotactic and immunomodulatory soluble factors (TGF-β, G-CSF, GM-CSF, MCP-1, IL-6, IL-8) were detected in high concentrations in CM and even higher in hUCBP. The results from 1H-NMR spectroscopic analysis of CM endorsed a better understanding of hMSCs metabolism during in vitro culture, and the relative composition of several metabolites present in CM and hUCBP was obtained. The data reinforces the potential use of hUCBP and CM in tissue regeneration and focus the possible use of hUCBP as a substitute for the FBS used in hMSCs in vitro culture.
- Semidirect Products and Split Short Five Lemma in Normal CategoriesPublication . Martins-Ferreira, Nelson; Montoli, Andrea; Sobral, ManuelaIn this paper we study a generalization of the notion of categorical semidirect product, as defined in [6], to a non-protomodular context of categories where internal actions are induced by points, like in any pointed variety. There we define semidirect products only for regular points, in the sense we explain below, provided the Split Short Five Lemma between such points holds, and we show that this is the case if the category is normal, as defined in [12]. Finally, we give an example of a category that is neither protomodular nor Mal’tsev where such generalized semidirect products exist.
- A Decomposition Formula for the Weighted CommutatorPublication . Martins-Ferreira, Nelson; Van der Linden, TimWe decompose the weighted subobject commutator of M. Gran, G. Janelidze and A. Ursini as a join of a binary and a ternary commutator.
- TBM-App: a clinical decision support system for tuberculous meningitisPublication . Santos, Luiz R A dos; Anselmo, Lívia M P; Oliveira, Lucas S; Merli, Fernanda S; Silva, Carla C; Prado, Gabriela C S; Crepaldi, Nathalia Yukie; Bernardi, Filipe A; Matheus A Marçal, Matheus A; R-Netto, Antonio; Rijo, Rui Pedro Charters Lopes; Bollela, Valdes R; Alves, DomingosTuberculosis (TB) was responsible for approximately 1.6 million deaths in 2017 and it is the deadliest among the infectious diseases, killing more than Acquired Immunodeficiency Syndrome (AIDS) related diseases. One of the most lethal forms of this disease is the central nervous system TB. The clinical and microbiological diagnosis of tuberculous meningitis (TBM) is still a challenge and to standardize the diagnosis and offer more reliable information to the decision-making process in the clinical practice, predictive scores were created and adapted for the Brazilian context. The score implementation will require staff training but has the potential to reduce time to the TBM diagnosis and therefore start correct treatment early. Although, there is a need to increase the access to the score and to facilitate its use among physicians to save time and resources. This study shows the design and development of a multiplatform mobile application to calculate the predictive score for tuberculous meningitis, in order to support clinical decisions. The preliminary results have shown an effective and versatile App, available to a variety of devices and which can still be available in places with limited or no internet access.
- SISTB: an ecosystem for monitoring TBPublication . Crepaldi, Nathalia Yukie; Lima, Vinicius Costa; Bernardi, Filipe Andrade; Santos, Luiz Ricardo Albano; Yamaguti, Verena Hokino; Pellison, Felipe Carvalho; Sanches, Tiago Lara Michelin; Miyoshi, Newton Shydeo Brandão; Ruffino-Netto, Antonio; Rijo, Rui Pedro Charters Lopes; Alves, DomingosTuberculosis (TB) is a curable disease, although it still kills thousands of people every year. There are several information systems and applications developed to assist the TB treatment, but many of these systems are isolated and are not able to exchange relevant information. In this way, a set of interoperable applications and decision support modules have been developed. A socio-technical approach was applied to incorporate key stakeholders in all development stages so that final tools fit the health service reality. A set of systems and applications, called the SISTB Ecosystem, has been designed to assist in the treatment of TB and to improve the routine of health professionals.
- Collagen surface modified poly(ε-caprolactone) scaffolds with improved hydrophilicity and cell adhesion propertiesPublication . Sousa, Inês; Mendes, Ausenda; Pereira, Rúben F.; Bártolo, Paulo J.Poly(ε-caprolactone) (PCL)/collagen scaffolds were produced using a four-step procedure comprising (i) the fabrication of PCL scaffolds through an additive bioextrusion system, (ii) the PCL surface modification using a plasma treatment, (iii) the acrylic acid (AAc) grafting by ultraviolet (UV) polymerization, and (iv) the immobilization of collagen into the scaffold surface through the carbodiimide chemistry. This procedure allowed the quick fabrication of highly porous scaffolds with interconnected pores, well-defined internal architecture and improved cell adhesion properties. The immobilization of collagen into the PCL surface led to a significant enhancement in the hydrophilicity, while the biological tests showed a further improvement in the adhesion of fibroblast cells. These results indicate that the collagen surface modification is an effective strategy to render the hydrophobic nature of PCL and overcome the limited cell interaction of 3D PCL scaffolds.
- Interlaminar fracture in woven carbon/epoxy laminatesPublication . Reis, Paulo N. B. ; Ferreira, José A. M. ; Costa, José D. M. ; Pereira, António M.This paper describes an experimental study developed to characterize the mode I and mode II fracture toughness of carbon/epoxy woven composites, using DCB and ENF tests, respectively. The laminates were manufactured using an epoxy resin and twelve woven balanced bi-directional layers of carbon fibres, all of them with the same orientation (0/90º). Significant instantaneous delaminations were observed particularly for the DCB specimen, which were responsible for an oscillatory behaviour of GI versus crack length. The maximum values obtained for GIC and GIIC were 281 and 1800 J/m2, respectively.