An Insight into the Release Kinetics

The authors acknowledge the financial support from Fundação para a Ciência e a Tecnologia (FCT-MEC), Portugal, through the dedicated project (PTDC/EDM-EDM/30828/2017) (BeLive) Publisher Copyright: © 2023 by the authors.This work explores the unique features of magnetic-responsive hydrogels to obtain liposomal hydrogel delivery platforms capable of precise magnetically modulated drug release based on the mechanical responses of these hydrogels when exposed to an external magnetic field. Magnetic-responsive liposomal hydrogel delivery systems were prepared by encapsulation of 1,2-dipalmitoyl-sn-glycero-3-phosphocoline (DPPC) multilayered vesicles (MLVs) loaded with ferulic acid (FA), i.e., DPPC:FA liposomes, into gelatin hydrogel membranes containing dispersed iron oxide nanoparticles (MNPs), i.e., magnetic-responsive gelatin. The FA release mechanisms and kinetics from magnetic-responsive liposomal gelatin were studied and compared with those obtained with conventional drug delivery systems, e.g., free liposomal suspensions and hydrogel matrices, to access the effect of liposome entrapment and magnetic field on FA delivery. FA release from liposomal gelatin membranes was well described by the Korsmeyer–Peppas model, indicating that FA release occurred under a controlled diffusional regime, with or without magnetic stimulation. DPPC:FA liposomal gelatin systems provided smoother controlled FA release, relative to that obtained with the liposome suspensions and with the hydrogel platforms, suggesting the promising application of liposomal hydrogel systems in longer-term therapeutics. The magnetic field, with low intensity (0.08 T), was found to stimulate the FA release from magnetic-responsive liposomal gelatin systems, increasing the release rates while shifting the FA release to a quasi-Fickian mechanism. The magnetic-responsive liposomal hydrogels developed in this work offer the possibility to magnetically activate drug release from these liposomal platforms based on a non-thermal related delivery strategy, paving the way for the development of novel and more efficient applications of MLVs and liposomal delivery systems in biomedicine.publishersversionpublishe

Modelização de separações por membrana através de métodos de refinamento de malha

Aplicou-se um modelo que conjuga a polarização da concentração e o transporte numa membrana para simular a ultrafiltração de soluções aquosas de PEG-3400. O problema incorpora o modelo de fricção binária desenvolvido a partir de uma modificação da equação de Maxwell-Stefan-Lightfoot. Desenvolveu-se um método numérico adaptativo eficiente para resolver simultaneamente as duas partes do modelo (camada de polarização e membrana). A resolução numérica do sistema algébrico-diferencial permitiu a ilustração adequada do fenómeno de rejeição aparente de soluto (em soluções aquosas de PEG-3400) assim como da queda de pressão em função do fluxo. Por outro lado, possibilitou a previsão adequada da influência de parâmetros físico-químicos e das condições de operação nesses fenómenos de rejeição, para além da correcta formação dos perfis de concentração e de fluxo quer na zona da camada de polarização como da membrana. A comparação com valores experimentais de ultrafiltração possibilita a validação do modelo no caso específico das soluções de PEG-3400. Os resultados de simulação dependem significativamente das características de resistência, Rm, da membrana que manifestam uma grande variabilidade de ensaio para ensaio e que influenciam o valor do coeficiente de equilíbrio, Keq

Structural and longitudinal analysis of the knowledge base on spin-off research

Following the dynamism in spin-off research, in this study we conduct a structural and longitudinal bibliometric analysis of a sample of 812 articles on spin-offs published in 234 journals included in the ISI Web of Knowledge over a period of three decades. The analyses do not seek to establish a new conceptualization but rather to reveal the intellectual structure of the field and how it has evolved, and the profile of the knowledge network established in the three perspectives: corporate, academic and entrepreneurial spin-offs. The diversity involved in the three streams of spin-off research signals substantial differences. Theoretically, transaction costs, agency and the resource-based view have remained a foundation of spin-off research, albeit that research has been driven more by the phenomena than by developing the theory. The more traditional focus on corporate spin-offs was followed by emphasis on academic spin-offs and more recently on entrepreneurial spin-offs. This shift has been accompanied by a more business/management theoretical orientation, replacing a more financial and taxation-based perspective underlying corporate spin-offs. This study systematizes the existing stock of knowledge and raises avenues for additional inquiry.info:eu-repo/semantics/publishedVersio

Magnetic stimulation of the angiogenic potential of mesenchymal stromal cells in vascular tissue engineering

The authors acknowledge the financial support from Fundação para a Ciência e a Tecnologia (FCT-MEC), Portugal, through the dedicated project [PTDC/EDM-EDM/30828/2017] (BeLive) and PhD grant [SFRH/BD/114043/2015] and  through the project [EXPL/CTM-POL/1117/1135/2012] Moreover, the authors thanks POR Lisboa 2020 for the research project [PRECISE, Project N. 16394]. We acknowledge Dr. Marta Teixeira and the IPATIMUP facilities for the development of the ex vivo CAM experiments. The authors acknowledge Prof. Reyes Mallada (University of Zaragoza, Spain) for the use of the vibrating sample magnetometer (VSM) equipment and Dr. Pavel Strichovanec (University of Zaragoza, Spain) for the technical assistance provided during the experiments. We also acknowledge the Instituto de Medicina Molecular (IMM, Lisboa) for the services provided concerning the use of the Confocal Scanning Microscopy (Zeiss LSM 710). Publisher Copyright: © 2021 The Author(s). Published by National Institute for Materials Science in partnership with Taylor & Francis Group.The growing prevalence of vascular diseases worldwide has emphasized the need for novel tissue-engineered options concerning the development of vascularized 3D constructs. This study reports, for the first time, the use of external magnetic fields to stimulate mesenchymal stromal cells (MSCs) to increase the production of vascular endothelial growth factor-A (VEGF-A). Polyvinylalcohol and gelatin-based scaffolds, containing iron oxide nanoparticles, were designed for optimal cell magnetic stimulation. While the application of static magnetic fields over 24 h did not impact on MSCs proliferation, viability and phenotypic identity, it significantly increased the production of VEGF-A and guided MSCs morphology and alignment. The ability to enhance MSCs angiogenic potential was demonstrated by the increase in the number of new vessels formed in the presence of MSCs conditioned media through in vitro and in vivo models. Ultimately, this study uncovers the potential to manipulate cellular processes through short-term magnetic stimulation.publishersversionpublishe

Effects of age-related cognitive deficits on EEG phase coherence

Body and brain undergo several changes with aging. One of these changes is the loss of neuroplasticity, which leads to the decrease of cognitive abilities. Hence the necessity of stopping or reversing these changes is of utmost importance to contemporary society. In the present work, electroencephalogram (EEG) markers of cognitive decline are sought whilst the subjects perform the Wisconsin Card Sorting Test (WCST). Considering the expected age-related cognitive deficits, WCST was applied to young and elder participants. The results suggest that coherence on theta and alpha EEG rhythms decrease with aging and increase with performance. Additionally, theta phase coherence seems more sensitive to performance, while alpha synchronization appears as a potential ageing markerFCT-Foundation for Science and Technology and Compete Program with the project reference FCOMP-01-0124-FED ER-021145 (PTDC/SAU-ENB/118383/2010

Biocatalytic CO2 absorption and structural studies of carbonic anhydrase under industrially-relevant conditions

UIDB/50006/2020 IF/00505/2014/CP1224/CT0004The unprecedently high CO2 levels in the atmosphere evoke the urgent need for development of technologies for mitigation of its emissions. Among the alternatives, the biocatalytic route has been claimed as one of the most promising. In the present work, the carbonic anhydrase from bovine erythrocytes (BCA) was employed as a model enzyme for structural studies in an aqueous phase at alkaline pH, which is typical of large-scale absorption processes under operation. Circular dichroism (CD) analysis revealed a high enzymatic stability at pH 10 with a prominent decrease of the melting temperature above this value. The CO2 absorption capacity of the aqueous solutions were assessed by online monitoring of pressure decay in a stainless-steel cell, which indicated a better performance at pH 10 with a kinetic rate increase of up to 43%, as compared to non-biocatalytic conditions. Even low enzyme concentrations (0.2 mg g−1) proved to be sufficient to improve the overall CO2 capture process performance. The enzyme-enhanced approach of CO2 capture presents a high potential and should be further studied.publishersversionpublishe

Low-carbon scenarios for the Brazilian power system

The Brazilian power generation sector faces a paradigm change driven, on one hand, by a shift from a hydropower dominated mix and, on the other, by international goals for reducing greenhouse gases emissions. The objective of this work was to evaluate five scenarios for the Brazilian power system until 2050 using a multi-criteria decision analysis tool. These scenarios include a baseline trend and low carbon policy scenarios based on carbon taxes and carbon emission limits. To support the applied methodology, a questionnaire was elaborated to integrate the perceptions of experts on the scenario evaluation process. Taking into account the results from multi-criteria analysis, scenario preference followed the order of increasing share of renewables in the power system. The preferable option for the future Brazilian power system is a scenario where wind and biomass have a major contribution. The robustness of the multi-criteria tool applied in this study was tested by a sensitivity analysis. This analysis demonstrated that, regardless the respondents’ preferences and backgrounds, scenarios with higher shares of fossil fuel sources are the least preferable option, while scenarios with major contributions from wind and biomass are the preferable option to supply electricity in Brazil through 2050.This research was supported by a Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Union Framework Programme, under project NETEP- European Brazilian Network on Energy Planning (PIRSES-GA-2013-612263)

Understanding cost escalation in nuclear reactor construction projects

This work seeks to evaluate overnight construction costs (OCC) and lead time escalation of nuclear reactors from 1955 to 2016. To this end, a comprehensive database of commercial Light Water Reactors (LWR) was developed and a statistical analysis was conducted. Findings reveal that there is significant delay in lead time, especially for the last generation reactors constructed from 2010’s. This results in the escalation of capital costs rather than a decline. Average OCC of newer reactors are 60% higher than the ones implemented in the earlier stages of the nuclear era. This suggests a negative learning curve effect for both OCC and lead time, which threats the market and financial sustainability of current and future nuclear energy projects. Although this is a general trend, this negative effect is country specific and, thus, induced by national policies and regulatory frameworks. Therefore, the role of nuclear technology to cope with the decarbonisation of the power sector must be better evaluated, taking into account the real cost impacts of nuclear technology implementation.This work was also funded by the Brazilian research funding agency CNPq.This work was funded by the Brazilian research funding agency CNPq and the Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Union Framework Programme, under the project NETEP- European Brazilian Network on Energy Planning (PIRSES-GA-2013-612263)

Quando o Intervalo QT é Curto Demais: Síncope Causada por Síndrome QT Curto

We report the case of a 52-year-old man who presented to our emergency department (ED) after three episodes of syncope in the seven hours before admission. During his stay in the ED he had recurrent ventricular tachycardia (VT) requiring external electrical cardioversion. A 12-lead electrocardiogram (ECG) showed a short QT (SQT) interval (270 ms, QTc 327 ms), with frequent R-on-T extrasystoles triggering sustained polymorphic VT. After exclusion of other precipitating causes, the patient was diagnosed as having SQT syndrome (SQTS) according to the Gollob criteria. To our knowledge, this is the first known documentation of an SQT-caused arrhythmic episode on a 12-lead ECG, as well as the first reported case of SQTS in Portugal. The patient received an implantable cardioverter-defibrillator and was discharged. At a follow-up assessment 14 months later he was symptom-free, interrogation of the device showed no arrhythmic events, and the ECG showed a QT interval of 320 ms (QTc 347 ms)

Testing different CNN architectures for semantic segmentation for landscaping with forestry robotics

Increasingly mechanized, leading to the emergence of forestry robotics. In this article, we present the results of our evaluation of a set of state-of-the-art convolutional neural network-based solutions for semantic segmentation using the Bonnetal open-source training and deployment framework, together with a custom-made solution based on an adaptation of an alternative decoder and encoder for that framework, the Adapnet++–eASPP architecture, in the context of a robotic perception pipeline designed to perform landscaping in woodlands to reduce the amount of living flammable material (the Fuel class) for wildfire prevention. Results show that, overall, Adapnet++–eASPP was the most robust and comprehensive encoder for our application, demonstrating a consistently high average level of performance in comparison to the other architectures, and displaying the greatest robustness of the group. With this solution, we demonstrated to be able to satisfy our requirements of a low rate of false positives for the Fuel class and operational performance of 10fps