Development of ion jelly thin films for electrochemical devices

Dissertação para obtenção do Grau de Doutor em Química SustentávelIonic liquids (ILs) are promising materials which have been used in a wide range of applications. However, their major limitation is their physical state. In order to address this challenge, a self-supported IL-based material was developed by combining gelatine with an IL, originating a quasi-solid material named Ion Jelly (IJ). This is a light flexible material, dimensionally stable, with promising properties to develop safe and highly conductive electrolytes. This thesis is focused on the characterization of IJ films based on different ILs. The conductive mechanisms of IJ materials were studied using dielectric relaxation spectroscopy (DRS) in the frequency range 10-1−106 Hz. The study was complemented by differential scanning calorimetry (DSC) and pulsed field gradient nuclear magnetic resonance (PFG NMR) spectroscopy. A glass transition was detected by DSC for all materials allowing to classify them as glass formers. From dielectric measurements, transport properties such as mobility and diffusion coefficients were extracted. Moreover, it was found that the diffusion coefficients and mobility are similar for the IL and IJ, especially for the IL EMIMDCA. Since for BMIMDCA, those properties significantly change upon hydration, the influence of water content [0.4 - 30% (w/w)] was also studied for the ILs. In particular for BMPyrDCA with 30% water, it was analyzed the reorientational polarization by the complex permittivity and electric modulus, from which three different processes were identified: a secondary relaxation with Arrhenian temperature dependence, the process that is believed to be behind the dynamic glass transition and the mobility of charge carriers. An application of the IJs was successfully explored with a chemoresistive gas sensor made up by different IJs as active layer, which is an electronic nose formed by an array of such sensors. The performance of this e-nose revealed its ability to correctly detect eight common volatile solvents

Caracterização do consumo de substâncias psicoactivas nos estudantes de medicina da Faculdade de Medicina da Universidade de Coimbra

Trabalho final de mestrado integrado em Medicina área científica de Farmacologia, apresentado à Faculdade de Medicina da Universidade de CoimbraIntrodução: Em Portugal são escassos os estudos que avaliem o consumo de substâncias psicoactivas pelos estudantes de Medicina. Investigações realizadas em outros países referem que a prevalência de consumo não difere entre estes e outros jovens pertencentes ao ensino superior. Objectivos: Analisar o padrão de consumo e as motivações que levam ao uso de substâncias psicoactivas pelos estudantes de Medicina da Faculdade de Medicina da Universidade de Coimbra. Métodos: Aplicação de questionário de preenchimento anónimo, distribuido por toda a comunidade estudantil do Mestrado Integrado em Medicina, em Outubro de 2011; 27,13% da população (426 alunos) colaborou no preenchimento do inquérito. Resultados: Praticamente não se verifica uma maior prevalência de consumo de substâncias psicoactivas em estudantes de Medicina relativamente a outros cursos do ensino superior. As excepções prendem-se com o consumo de psicofármacos, que assume valores mais elevados, e de ecstasy, com uma menos prevalência. As substâncias mais utilizadas foram o álcool, bebidas energéticas e tabaco. No que toca a substâncias ilícitas, os canabinóides ocupam o primeiro lugar de consumo. O factor diversão foi considerado o mais importante para o consumo das substâncias questionadas. Não se verificou associação entre a alteração de residência durante o período lectivo e o consumo da maioria das substâncias psicoactivas, exceptuando-se na ingestão de bebidas energéticas. Verificou-se associação (p<0,05) entre o ano de curso e a prevalência de consumo de álcool, bebidas energéticas, substâncias canabinóides e psicofármacos tranquilizantes. Conclusão: O consumo de substâncias psicoactivas pelos estudantes de Medicina não difere do de outros estudantes, à excepção de medicamentos psicotrópicos e de ecstasy, que adquirem aqui uma maior e menor prevalência, respectivamente. A utilização das substâncias investigadas é, tendencialmente, de carácter experimental, à excepção do álcool, que apresenta elevada frequência de consumo na questão “consumo no último mês”. A principal motivação enunciada pelos estudantes para a utilização de substâncias psicoactivas foi o factor diversão.Introduction: In Portugal, there are few studies to evaluate the use of psychoactive substances by medical students. In other countries, studies report that the prevalence of consumption did not differ between these and other college students. Objectives: To analyze the pattern of psychoactive substance’s use by students of Medicine from Faculty of Medicine of the University of Coimbra, and their motivations. Methods: Application of anonymous questionnaire, distributed to all the student community of the Integrated Master in Medicine, in October 2011; 27.13% of the population (426 students) had completed the survey. Results: There is no greater prevalence of psychoactive substances among medical students than other college students. However, there are two exceptions: the use of psychotropic drugs takes higher values, and ecstasy has lower prevalence. The most used substances all-time were alcohol, energy drinks and tobacco. From the group of illegal substances, cannabinoids occupy the first place of consumption. “To have fun” was considered the most important factor for the use of substances questioned. No association was found between the change of residence during class time and most of psychoactive substance consumption, except for energy drinks. An association (p<0.05) was verified between the year of the course in the integrated master of medicine and consumption of alcohol, energy drinks, cannabinoids and psychotropic tranquilizers drugs. Conclusion: The use of psychoactive drugs by medical students does not differ from other college student, except for psychotropic medication and ecstasy, which have a higher and lower prevalence, respectively. The use of investigated substances tends to be experimental, except for the alcohol, which has a high frequency of use in question “use in last month”. The main motivation enunciated by students for the use of psychoactive substances was “to have fun”

A Three-Way Knot: Privacy, Fairness, and Predictive Performance Dynamics

As the frontier of machine learning applications moves further into human interaction, multiple concerns arise regarding automated decision-making. Two of the most critical issues are fairness and data privacy. On the one hand, one must guarantee that automated decisions are not biased against certain groups, especially those unprotected or marginalized. On the other hand, one must ensure that the use of personal information fully abides by privacy regulations and that user identities are kept safe. The balance between privacy, fairness, and predictive performance is complex. However, despite their potential societal impact, we still demonstrate a poor understanding of the dynamics between these optimization vectors. In this paper, we study this three-way tension and how the optimization of each vector impacts others, aiming to inform the future development of safe applications. In light of claims that predictive performance and fairness can be jointly optimized, we find this is only possible at the expense of data privacy. Overall, experimental results show that one of the vectors will be penalized regardless of which of the three we optimize. Nonetheless, we find promising avenues for future work in joint optimization solutions, where smaller trade-offs are observed between the three vectors.Comment: 12, 6 figures and 2 table

Formação de professores dos anos iniciais: conhecimento profissional docente ao explorar a introdução do conceito de fração

Esta comunicação tem o propósito de analisar a ampliação de conhecimentos necessários ao ensino de frações explicitados por um grupo de professoras que leciona para os anos iniciais. Nele foi possível, fundamentado em Vergnaud e Nunes, analisar e refletir sobre a necessidade de introduzir as frações por meio de diferentes situações. Além disso, a formação permitiu ao docente investigar a própria prática, refletir sobre resultados de pesquisa e utilizar diversos recursos metodológicos. Sob a perspectiva de Ball, a análise da observação das aulas, um ano após a formação, evidencia que a ampliação dos conhecimentos ocasionou mudanças na prática docente. Durante as aulas, a introdução da fração foi realizada por meio da ideia de partição, ao mesmo tempo o número fracionário foi apresentado como um quociente por meio de recursos como a literatura infantil e recortes

Differentially-Private Data Synthetisation for Efficient Re-Identification Risk Control

Protecting user data privacy can be achieved via many methods, from statistical transformations to generative models. However, all of them have critical drawbacks. For example, creating a transformed data set using traditional techniques is highly time-consuming. Also, recent deep learning-based solutions require significant computational resources in addition to long training phases, and differentially private-based solutions may undermine data utility. In this paper, we propose $\epsilon$-PrivateSMOTE, a technique designed for safeguarding against re-identification and linkage attacks, particularly addressing cases with a high re-identification risk. Our proposal combines synthetic data generation via noise-induced interpolation to obfuscate high-risk cases while maximising the data utility of the original data. Compared to multiple traditional and state-of-the-art privacy-preservation methods on 17 data sets, $\epsilon$-PrivateSMOTE achieves competitive results in privacy risk and better predictive performance than generative adversarial networks, variational autoencoders, and differential privacy baselines. It also improves energy consumption and time requirements by at least a factor of 11 and 15, respectively.Comment: 9 pages, 4 figures and 2 table

Notch Pathway Modulation on Bone Marrow-Derived Vascular Precursor Cells Regulates Their Angiogenic and Wound Healing Potential

Bone marrow (BM) derived vascular precursor cells (BM-PC, endothelial progenitors) are involved in normal and malignant angiogenesis, in ischemia and in wound healing. However, the mechanisms by which BM-PC stimulate the pre-existing endothelial cells at sites of vascular remodelling/recovery, and their contribution towards the formation of new blood vessels are still undisclosed. In the present report, we exploited the possibility that members of the Notch signalling pathway, expressed by BM-PC during endothelial differentiation, might regulate their pro-angiogenic or pro-wound healing properties. We demonstrate that Notch pathway modulates the adhesion of BM-PC to extracellular matrix (ECM) in vitro via regulation of integrin alpha3beta1; and that Notch pathway inhibition on BM-PC impairs their capacity to stimulate endothelial cell tube formation on matrigel and to promote endothelial monolayer recovery following wounding in vitro. Moreover, we show that activation of Notch pathway on BM-PC improved wound healing in vivo through angiogenesis induction. Conversely, inoculation of BM-PC pre-treated with a gamma secretase inhibitor (GSI) into wounded mice failed to induce angiogenesis at the wound site and did not promote wound healing, presumably due to a lower frequency of BM-PC at the wound area. Our data suggests that Notch pathway regulates BM-PC adhesion to ECM at sites of vascular repair and that it also regulates the capacity of BM-PC to stimulate angiogenesis and to promote wound healing. Drug targeting of the Notch pathway on BM-PC may thus represent a novel strategy to modulate neo-angiogenesis and vessel repair