Browsing by Author "Pereira, Eduardo"
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- Benefits of tranexamic acid in total knee arthroplasty: a classification and regression tree analysis in function of instrumentation, BMI, and genderPublication . Pereira, Eduardo; Carvalho, Maria Miguel; Oliveira, Tiago; Sacramento, Telmo; Cruz, Henrique; Viegas, Rui; Fontes, Ana Paula; Marreiros, Ana; Sousa, João PauloTranexamic acid (TXA) is an antifibrinolytic drug that reduces blood loss in patients that undergo Total knee arthroplasty (TKA). Few studies compare its effect on conventional instrumentation (CI) versus patient-specific instrumentation (PSI). The main objective of this study was to understand analytically how TXA usage in both instrumentations influenced blood loss in TKA differently and see if the differences seen could be explained by the patient’s body mass index (BMI) and gender. This nonrandomized retrospective study sample consisted of 688 TKA procedures performed on patients who had symptomatic arthrosis resistant to conservative treatment. Descriptive analysis was used to evaluate blood loss using hemoglobin (Hb) mean values and mean variation (%). The Classification and Regression Tree (CRT) method was applied to understand how the independent variables affected the dependent variable. Comparing patients submitted to the same instrumentation, where some received TXA and others did not, patients that received TXA had lower blood loss. Comparing patients who underwent TKA with different instrumentations and without the use of TXA, it was found that patients who underwent TKA with PSI had lower blood loss than those who underwent TKA with CI. However, when these same instruments were compared again, but associated with the use of TXA, the opposite was true with patients undergoing TKA with PSI showing greater blood loss than patients undergoing TKA with CI. TXA usage in TKA is significantly beneficial in minimizing blood loss and regardless of instrumentation. When using TXA, the lowest blood loss was obtained in patients with higher BMI and submitted to TKA with CI. This is most likely explained by the synergistic antifibrotic effect of TXA with adipokines, such as plasminogen activator inhibitor-1 (PAI-1), found in the femoral bone marrow which is perforated using CI. If, however, TXA wasn’t used, the lowest blood loss was obtained in patients submitted to TKA with PS
- A Demonstrator for future fiber-optic active SMART repeatersPublication . Cruz, Nuno A.; Silva, António; Zabel, Friedrich; Ferreira, Bruno; Jesus, Sergio; Martins, Marcos S.; Pereira, Eduardo; Matos, Tiago; Viegas, Ruben; Rocha, João; Faria, JoãoThe deep-sea environment still presents many challenges for systematic, comprehensive data acquisition. The current generation of SMART cables incorporates low-power sensors in long-range telecommunication cables to improve knowledge of ocean variables, aid in earthquake and tsunami warnings, and enhance coastal protection. The K2D Project seeks to expand SMART cables' capabilities by increasing the diversity of sensors along deep water cables, integrating active devices, and leveraging mobile platforms like deep-water AUVs, thereby improving spatial coverage and advancing ocean monitoring technology. This paper discusses a demonstration of these capabilities, focusing on the description of the main building blocks developed along the project, with results from a sea deployment in September 2023.
- Network nodes for ocean data exchange through submarine fiber optic cable repeatersPublication . Martins, M. S.; Cruz, Nuno A.; Silva, António; Ferreira, Bruno; Zabel, Fred; Matos, Tiago; Jesus, Sergio; Pinto, André; Pereira, Eduardo; Matos, Aníbal; Faria, Carlos; Tieppo, Marcos; Goncalves, L. M.; Rocha, João; Faria, JoãoAs humanity progresses and globalization advances, humanized environment and associated systems increase in complexity and size. In earth systems, oceans represent an essential element of equalization and normal functioning. Ocean-atmospheric interactions are nowadays believed to be at the heart of all earth vital signs and climatic behaviours, and therefore are essential to accurate monitoring and understanding of earth systems. The work presented is a preliminary result of the K2D- Knowledge and Data from the Deep to Space, project which addresses the challenge of creating underwater network nodes to provide power and communication to land through the submarine fiber optic cable repeaters. The N2ODE system will consist of a set of subsystems that will allow continuous monitoring and interaction with fixed and mobile underwater devices.
- Numerical analysis of the flow field and cross section design implications in a multifunctional artificial reefPublication . Maslov, Dmytro; Pereira, Eduardo; Duarte, Duarte; Miranda, Tiago; Ferreira, Vasco; Tieppo, Marcos; Cruz, Fábio; Johnson, JessicaNowadays, multifunctional artificial reefs are integrated in coastal areas all around the world. The design of such structures is currently complex and subjective. In this context, it is essential to improve overall design approaches to more effectively relate artificial reef geometry, function and optimal performance to specific deployment sites. Part of the solution to this challenge may lie in the use of in situ data to study the hydrodynamic performance of prospective artificial reefs. This research addresses this issue by performing a numerical investigation of the flow transformation of two similar artificial reef geometries, and the analysis of performance indicators based on (i) artificial reef assembly cross section, (ii) upwelling and (iii) wake regions evaluation, (iv) efficiency indices and (v) streamlines particles. Based on typical data related to wave action, a velocity inlet boundary condition was defined adopting the non-uniform velocity distribution, aimed at simulating the most realistic boundary con-dition at the chosen deployment location. The results showed that the multifunctional artificial reef assembly with the droplet shape cross section exhibited enhanced function performance when compared to a circular shape cross section by providing significantly higher values of the upwelling velocity, wake region and associated efficiency indices. In addition, the procedure presented in this study, which considers oceanographic data at the deployment site, the geometry of the artificial reef, in situ flow characteristics and boundary conditions, as well as the devised fluid flow performance indicators, can be used for the design of artificial reefs during the concept stage in an objective manner to consider the local design requirements.
- Submarine cables as precursors of persistent systems for large scale oceans monitoring and autonomous underwater vehicles operationPublication . Tieppo, Marcos; Pereira, Eduardo; Garcia, Laura Gonzalez; Rolim, Margarida; Castanho, Emanuel; Matos, Anibal; Silva, António; Ferreira, Bruno; Pascoal, Maria; Almeida, Eduardo; Costa, Filipe; Zabel, Fred; Faria, Joao; Azevedo, Jose; Alves, Jose; Moutinho, Jose; Goncalves, Luis; Martins, Marcos; Cruz, Nuno; Abreu, Nuno; Silva, Pedro; Viegas, Rúben; Jesus, Sergio; Chen, Tania; Miranda, Tiago; Papalia, Alan; Hart, Douglas; Leonard, John; Haji, Maha; de Weck, Olivier; Godart, Peter; Lermusiaux, PierreLong-term and reliable marine ecosystems monitoring is essential to address current environmental issues, including climate change and biodiversity threats. The existing oceans monitoring systems show clear data gaps, particularly when considering characteristics such as depth coverage or measured variables in deep and open seas. Over the last decades, the number of fixed and mobile platforms for in situ ocean data acquisition has increased significantly, covering all oceans' regions. However, these are largely dependent on satellite communications for data transmission, as well as on research cruises or opportunistic ship surveys, generally presenting a lag between data acquisition and availability. In this context, the creation of a widely distributed network of SMART cables (Science Monitoring And Reliable Telecommunications) - sensors attached to submarine telecommunication cables - appears as a promising solution to fill in the current ocean data gaps and ensure unprecedented oceans health continuous monitoring. The K2D (Knowledge and Data from the Deep to Space) project proposes the development of a persistent oceans monitoring network based on the use of telecommunications cables and Autonomous Underwater Vehicles (AUVs). The approach proposed includes several modules for navigation, communication and energy management, that enable the cost-effective gathering of extensive oceans data. These include physical, chemical, and biological variables, both registered with bottom fixed stations and AUVs operating in the water column. The data that can be gathered have multiple potential applications, including oceans health continuous monitoring and the enhancement of existing ocean models. The latter, in combination with geoinformatics and Artificial Intelligence, can create a continuum from the deep sea to near space, by integrating underwater remote sensing and satellite information to describe Earth systems in a holistic manner.