361 research outputs found
Intracellular label-free detection of mesenchymal stem cell metabolism within a perivascular niche-on-a-chip
No full textThe stem cell niche at the perivascular space in human tissue plays a pivotal role in dictating the overall fate of stem cells within it. Mesenchymal stem cells (MSCs) in particular, experience influential microenvironmental conditions, which induce specific metabolic profiles that affect processes of cell differentiation and dysregulation of the immunomodulatory function. Reports focusing specifically on the metabolic status of MSCs under the effect of pathophysiological stimuli - in terms of flow velocities, shear stresses or oxygen tension - do not model heterogeneous gradients, highlighting the need for more advanced models reproducing the metabolic niche. Organ-on-a-chip technology offers the most advanced tools for stem cell niche modelling thus allowing for controlled dynamic culture conditions while profiling tuneable oxygen tension gradients. However, current systems for live cell detection of metabolic activity inside microfluidic devices require the integration of microsensors. The presence of such microsensors poses the potential to alter microfluidics and their resolution does not enable intracellular measurements but rather a global representation concerning cellular metabolism. Here, we present a metabolic toolbox coupling a miniaturised in vitro system for human-MSCs dynamic culture, which mimics microenvironmental conditions of the perivascular niche, with high-resolution imaging of cell metabolism. Using fluorescence lifetime imaging microscopy (FLIM) we monitor the spatial metabolic machinery and correlate it with experimentally validated intracellular oxygen concentration after designing the oxygen tension decay along the fluidic chamber by in silico models prediction. Our platform allows the metabolic regulation of MSCs, mimicking the physiological niche in space and time, and its real-time monitoring representing a functional tool for modelling perivascular niches, relevant diseases and metabolic-related uptake of pharmaceuticals
Preliminary Validation of an Editable Virtual Reality Simulator for Minimally Invasive Surgical Training
No full textMIS-SIM is a virtual reality (VR) environment designed and developed for the creation of virtual scenarios that can be used to train and acquire basic and advance laparoscopic skills. The environment is composed by a task editor where a content creator design and develop tasks for the simulator to play. Once they are completed, objective metrics are automatically stored and examined in MIS-SIM’s server so they can be displayed by an online platform. The project was validated in Semmelweis University in Budapest, Hungary where an experienced professor designed tasks for 16 young surgeons (PGY 3-4-5) from different surgical fields (gynaecology, general-, plastic-, vascular-, thoracic-, neurosurgery, etc.) with different experiences in laparoscopy. Each participant fulfilled each task as if they were completing them on physical simulator.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Medical Instruments & Bio-Inspired Technolog
Side-scan sonar imaging data of underwater vehicles for mine detection
No full textSantos, N. P., Moura, R., Torgal, G. S., Lobo, V., & Neto, M. D. C. (2024). Side-scan sonar imaging data of underwater vehicles for mine detection. Data in brief, 53, 1-8. Article 110132. https://doi.org/10.1016/j.dib.2024.110132, https://doi.org/10.6084/m9.figshare.24574879 --- This work was supported by the national project MArIA - Plataforma Integrada de desenvolvimento de modelos de Inteligência artificial para o mar, with grant number POCI-05-5762-FSE-000400. The research conducted by Ricardo Moura was funded by the Fundação para a Ciência e a Tecnologia (FCT) - Center for Mathematics and Applications (NOVA Math) under the projects UIDB/00297/2020 (https://doi.org/10.54499/UIDB/00297/2020) and UIDP/00297/2020 (https://doi.org/10.54499/UIDP/00297/2020). The research carried out by Victor Lobo and Miguel de Castro Neto was supported by national funds through FCT under the project - UIDB/04152/2020 - Centro de Investigação em Gestão de Informação (MagIC)/NOVA IMS.Unmanned vehicles have become increasingly popular in the underwater domain in the last decade, as they provide better operation reliability by minimizing human involvement in most tasks. Perception of the environment is crucial for safety and other tasks, such as guidance and trajectory control, mainly when operating underwater. Mine detection is one of the riskiest operations since it involves systems that can easily damage vehicles and endanger human lives if manned. Automating mine detection from side-scan sonar images enhances safety while reducing false negatives. The collected dataset contains 1170 real sonar images taken between 2010 and 2021 using a Teledyne Marine Gavia Autonomous Underwater Vehicle (AUV), which includes enough information to classify its content objects as NOn-Mine-like BOttom Objects (NOMBO) and MIne-Like COntacts (MILCO). The dataset is annotated and can be quickly deployed for object detection, classification, or image segmentation tasks. Collecting a dataset of this type requires a significant amount of time and cost, which increases its rarity and relevance to research and industrial development.publishersversionpublishe
Análise da influência das entradas e componentes do sistema de produção sobre a produtividade das empresas
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção
Price setting in the euro area: Some stylised facts from Individual Producer Price Data
No full textThis paper documents producer price setting in 6 countries of the euro area: Germany, France, Italy, Spain, Belgium and Portugal. It collects evidence from available studies on each of those countries and also provides new evidence. These studies use monthly producer price data. The following five stylised facts emerge consistently across countries. First, producer prices change infrequently: each month around 21% of prices change. Second, there is substantial cross-sector heterogeneity in the frequency of price changes: prices change very often in the energy sector, less often in food and intermediate goods and least often in non-durable non- food and durable goods. Third, countries have a similar ranking of industries in terms of frequency of price changes. Fourth, there is no evidence of downward nominal rigidity: price changes are for about 45% decreases and 55% increases. Fifth, price changes are sizeable compared to the inflation rate. The paper also examines the factors driving producer price changes. It finds that costs structure, competition, seasonality, inflation and attractive pricing all play a role in driving producer price changes. In addition producer prices tend to be more flexible than consumer prices.
Epidemiological and ecological determinants of Zika virus transmission in an urban setting
No full textThis is the author accepted manuscript. The final version is available from eLife Sciences Publications via the DOI in this record.The Zika virus has emerged as a global public health concern. Its rapid geographic expansion is attributed to the success of Aedes mosquito vectors, but local epidemiological drivers are still poorly understood. Feira de Santana played a pivotal role in the Chikungunya epidemic in Brazil and was one of the first urban centres to report Zika infections. Using a climate-driven transmission model and notified Zika case data, we show that a low observation rate and high vectorial capacity translated into a significant attack rate during the 2015 outbreak, with a subsequent decline in 2016 and fade-out in 2017 due to herd-immunity. We find a potential Zika-related, low risk for microcephaly per pregnancy, but with significant public health impact given high attack rates. The balance between the loss of herd-immunity and viral re-importation will dictate future transmission potential of in this urban setting.Funding:
European Research Council (614725-PATHPHYLODYN): Oliver G Pybus
Royal Society: Mario Recker
Wellcome Trust & Royal Society (204311/Z/16/Z): Nuno Rodrigues Faria
Engineering and Physical Sciences Research Council: Ben Lambert
European Research Council (268904 - DIVERSITY): José Lourenço; Andrew Walker
International Development Emerging Pandemic Threats Program-2 (AID-OAA-A-14-00102): Moritz UG Kraeme
Grasp-RCNN for a two-fingered pinch-gripper: A multiple RCNN approach
No full textIntroduction - Grasping unknown objects is an important ability for robots in logistic environments. While humans have an excellent understanding of how to grasp objects because of their visual perception and understanding of the 3D world, robotic grasping is still a challenge. Due to the fast-growing development of deep learning methods, it is now possible to train deep neural networks on this grasp task.Objective - This thesis proposes a bin-picking pipeline that uses deep learning to take care of the perception and estimation task. The pipeline can predict grasps for known and unknown objects with a two-fingered pinch-gripper in real-world environments in a single object and multi-object scenes.Method - A grasp annotation tool has been developed to generate a wide variety of grasps in the training data that are antipodal and collision-free. Together with annotated objects, the generated grasps are used to train Grasp-RCNN. The developed Grasp-RCNN combines an object- and a grasp-detection network to predict objects masks and grasps, and a decision algorithm that picks the best-estimated grasp based on a grasp score.Results - Robotic experiments demonstrate that the proposed method allows a robot gripper to grasp both known and unknown objects in single-object and multi-object scenes with a total success-rate of 89.7% and 81.0% with average process-times of 616 ms and 739 ms per scene respectively. In a bin-picking scene a success-rate of 87.5% with a process-time of 1235 ms is achieved.Conclusion - These results indicate that the proposed Grasp-RCNN is able to grasp known and unknown objects with an accuracy that is comparable to the state-of-the-art. For production purposes, the speed of the network still can be improved.Mechanical Engineering | BioMechanical Desig
Seismic assessment of nineteenth and twentieth centuries URM buildings in Lisbon: structural features and derivation of fragility curves
No full textThe article addresses the seismic vulnerability assessment of a typology of unreinforced masonry buildings constructed in Lisbon between the nineteenth and the twentieth centuries. The main architectural and structural features of these buildings are presented. This supported the identification of the main uncertainties affecting their seismic performance and the definition of classes of buildings representative of the typology. The seismic assessment includes the generation of fragility curves that combine the in-plane and out-of-plane response following different criteria and methods of analyses. The results put in evidence the seismic vulnerability of this class of buildings. Considering the earthquake-resistant code for Lisbon with a return period of 475 years, about 50% probability of having heavy damage and about 30% probability of collapse were estimated. The structural intervention on these buildings is urgent in order to reduce losses due to future earthquakes. Further studies for the assessment of similar buildings in Lisbon and elsewhere can be developed using the adopted procedure.The first author would like to acknowledge the financial support of Fundacao para a Ciencia e a Tecnologia (FCT, Ministerio da Educacao e Ciencia, Portugal) through the scholarship PD/BD/106076/2015 through the FCT Doctoral Program: Analysis and Mitigation of Risks in Infrastructures, INFRARISK-(http://infrarisk.tecnico.ulisboa.pt).The authors would also like to acknowledge the contribution from Bruno Silva (Instituto Superior Tecnico) and Nuno Mendes (University of Minho) regarding the ambient vibration tests
On some criticisms of critical realism in economics
No full textCopyright © The Author 2007. Published by Oxford University Press on behalf of the Cambridge Political Economy Society. All rights reserved.Methodological comments on critical realism in economics have proliferated over the past decade - typically focusing on Tony Lawson's Economics and Reality and Reorienting Economics, which constitute the core of this project. In the present paper we select a series of important, mostly very recent arguments against critical realism in economics and assess their merits and demerits
Author Correction: Genomic basis for RNA alterations in cancer
No full textAuthor Correction: Genomic basis for RNA alterations in cance
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