Label-free detection of biomolecules with Ta2O5-based field effect devices

Dissertação para obtenção do Grau de Doutor em Nanotecnologias e NanociênciasInternational Iberian Nanotechnology Laboratory (INL

Colite isquémica em doente hemodialisado com doença renal crónica

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2016A Isquémia Intestinal é uma patologia vascular que afeta a circulação esplâncnica com grau de lesão variável. As suas caraterísticas, localização e prognóstico variam de acordo com os fatores de risco, co-morbilidades e etiologia da patologia. É pouco comum na população em geral, mas relativamente frequente em determinados doentes. Os doentes com doença renal terminal sob hemodiálise estão entre a população de maior risco. O diagnóstico e intervenção precoces são difíceis uma vez que a apresentação clínica, laboratorial e imagiológica é inespecífica, no entanto são necessários para contrariar a elevada mortalidade da doença. Caso clínico: Doente do sexo masculino de 49 anos que recorre ao SU por dor abdominal na fossa ilíaca direita e disúria. Com antecedentes de Diabetes Mellitus tipo 2, Hipertensão Arterial, Obesidade, Doença arterial periférica com amputação de ambos os membros inferiores e Doença Renal Crónica, sob hemodiálise. À admissão com abdómen globoso e distendido, doloroso à palpação na fossa ilíaca direita e coto esquerdo com sinais inflamatórios. Analiticamente com leucocitose e neutrofilia, PCR 30.46. Por agravamento do quadro abdominal realizou laparotomia exploratória com diagnóstico intraoperatório de necrose isquémica segmentar do cego. Em conclusão, enquanto na população em geral a colite isquémica é pouco comum, mais frequentemente do tipo oclusivo e afetando o cólon esquerdo, num doente com doença renal terminal em hemodialise é uma patologia com maior incidência, normalmente do tipo não oclusivo, com afeção do cólon direito e prognóstico reservado, devendo ser investigada. O diagnóstico de Isquemia intestinal deve ser ponderado de acordo com as caraterísticas e fatores de risco de cada doente, de forma a ser possível um diagnóstico e intervenção precoces e dirigidos.Intestinal ischemia is a vascular disease that affects the splanchnic circulation with variable degree of injury. Its characteristics, location and prognosis vary depending on the risk factors, co-morbidities and etiology of the disease. It isn't common in the general population, but relatively common in certain patients. Chronic renal disease patients on hemodialysis are among the high-risk population. Early diagnosis and intervention are difficult because the clinical presentation, laboratory and imaging are non-specific, but are needed to counteract the high mortality of the disease. Clinical case: Male patient, 49 years old, refers to the urgency service because of abdominal pain in the right iliac fossa and dysuria with a history of type 2 diabetes mellitus , hypertension, obesity , peripheral arterial disease with amputation of both lower limbs and chronic renal disease under hemodialysis . At admission abdomen was distended, painful at palpation in the right iliac fossa and inflammatory signs in left amputated extremity. Analytically with leukocytosis and neutrophilia , PCR 30.46 . Due to abdominal aggravation, exploratory laparotomy with intraoperative diagnosis of ischemic segmental necrosis of cecum was made. In conclusion, while in the general population ischemic colitis isn't common, more often occlusive and affecting the left colon, in a patient with chronic kidney disease on hemodialysis it is a disease with higher incidence, usually of the non-occlusive type, affecting the right colon with a poor prognosis, and should be investigated. The diagnosis of intestinal ischemia should be weighted according to the characteristics and risk factors of each patient in order to be possible early and directed diagnosis and intervention

Metal oxide-based photocatalytic paper: A green alternative for environmental remediation

The interest in advanced photocatalytic technologies with metal oxide-based nanomaterials has been growing exponentially over the years due to their green and sustainable characteristics. Photocatalysis has been employed in several applications ranging from the degradation of pollutants to water splitting, CO2 and N2 reductions, and microorganism inactivation. However, to maintain its eco-friendly aspect, new solutions must be identified to ensure sustainability. One alternative is creat-ing an enhanced photocatalytic paper by introducing cellulose-based materials to the process. Paper can participate as a substrate for the metal oxides, but it can also form composites or membranes, and it adds a valuable contribution as it is environmentally friendly, low-cost, flexible, recyclable, lightweight, and earth abundant. In term of photocatalysts, the use of metal oxides is widely spread, mostly since these materials display enhanced photocatalytic activities, allied to their chemical stability, non-toxicity, and earth abundance, despite being inexpensive and compatible with low-cost wet-chemical synthesis routes. This manuscript extensively reviews the recent developments of using photocatalytic papers with nanostructured metal oxides for environmental remediation. It focuses on titanium dioxide (TiO2) and zinc oxide (ZnO) in the form of nanostructures or thin films. It discusses the main characteristics of metal oxides and correlates them to their photocatalytic activity. The role of cellulose-based materials on the systems’ photocatalytic performance is extensively discussed, and the future perspective for photocatalytic papers is highlighted.publishersversionpublishe

Os direitos laborais na economia de plataforma

A economia de plataforma é um fenómeno que surgiu acompanhado de modelos de negócio revolucionários, que visam aproximar a oferta e a procura. Todavia, além das soluções que promovem a qualidade de vida e a inclusão, esta nova realidade trouxe consigo múltiplos desafios ao mercado de trabalho. É precisamente, neste contexto, que a presente dissertação visa dar o seu contributo, sendo efetuada uma primeira abordagem global ao surgimento das plataformas em linha e, consequente, aparecimento da economia de plataforma, esclarecendo algumas questões relevantes a nível conceptual, e ponderando os impactos práticos sentidos. Neste seguimento, foram reunidas as condições por fim de realizar uma análise jurídica sobre o tema, focada no Direito do Trabalho. Esta análise tem como tema central a diferença entre o contrato de trabalho e de prestação de serviços e as relações atípicas de emprego. Contudo, é inevitável concluir que o quadro jurídico atual não dá resposta a todos os problemas ao longo da dissertação analisados. Assim, procedemos à investigação de diversas sugestões, que podem constituir respostas ao desafio digital, que atualmente vivemos. A inevitável escolha política na regulamentação do trabalho prestado através de plataformas em linha terá um incalculável impacto social e económico, arriscando-se a contribuir para o fim destes recentes modelos de negócio, ou para a implementação de modelos melhorados, que permitam que uma imensurável força de trabalho, tenha a possibilidade de obter rendimentos, ou aumentar os já auferidos, gozando, simultaneamente, de condições de trabalho, acesso à proteção social e negociação coletiva.The platform economy is a phenomenon that has emerged accompanied by revolutionary business models, which aim to bring supply and demand closer together. However, besides the solutions that promote quality of life and inclusion, this new reality has brought multiple challenges to the job market. It is precisely in this context that this dissertation aims to make its contribution, with a first global approach being made to the emergence of online platforms and, consequently, the emergence of the gig economy, clarifying some relevant issues at a conceptual level, and considering practical impacts. In this follow-up, the conditions were met in order to carry out a legal analysis on the topic, focused on Labor Law. This analysis has, as its central theme, the difference between the employment and service contract and the atypical employment relationships. However, it is inevitable to conclude that the current legal framework does not respond to all the problems analyzed throughout the present dissertation. Thus, we proceeded to the investigation of several suggestions, which may constitute responses to the digital challenge, that we currently live. The inevitable political choice in the regulation of work, provided through online platforms, will have an incalculable social and economic impact, risking to contribute to the end of these recent business models, or to the implementation of improved models, that allow an immeasurable workforce, to have the possibility of obtaining income, or increase the income already earned, while enjoying working conditions, access to social protection and collective bargaining

Microwave-Assisted Hydrothermal Synthesis of Zn2SnO4 Nanostructures for Photocatalytic Dye Degradation

Zinc-tin oxide (ZTO) nanostructures appear as one of the most promising material systems for a new generation of nanodevices. In this work, a microwave-assisted hydrothermal synthesis to produce different shapes of Zn2SnO4 nanostructures (nanoparticles, octahedrons and nanoplates) is presented. Reproducible and homogeneous results were obtained with the advantage of reducing up to 20 h the synthesis time when compared to using a conventional oven. Furthermore, the photocatalytic activity of the Zn2SnO4 nanostructures in the degradation of rhodamine B under UV light was studied. Zn2SnO4 nanoparticles demonstrated better performance with >90% of degradation being achieved in 2.5 h.publishersversionpublishe

effect of physical parameters

POCI-01-0145-FEDER-007688. SFRH/BD/131836/2017. SFRH/BD/122286/2016.ZnSnO3 semiconductor nanostructures have several applications as photocatalysis, gas sensors, and energy harvesting. However, due to its multicomponent nature, the synthesis is far more complex than its binary counter parts. The complexity increases even more when aiming for low-cost and low-temperature processes as in hydrothermal methods. Knowing in detail the influence of all the parameters involved in these processes is imperative, in order to properly control the synthesis to achieve the desired final product. Thus, this paper presents a study of the influence of the physical parameters involved in the hydrothermal synthesis of ZnSnO3 nanowires, namely volume, reaction time, and process temperature. Based on this study a growth mechanism for the complex Zn:Sn:O system is proposed. Two zinc precursors, zinc chloride and zinc acetate, were studied, showing that although the growth mechanism is inherent to the material itself, the chemical reactions for different conditions need to be considered.publishersversionpublishe

Chapter Hydrothermal Synthesis of Zinc Tin Oxide Nanostructures for Photocatalysis, Energy Harvesting and Electronics

The massification of Internet of Things (IoT) and Smart Surfaces has increased the demand for nanomaterials excelling at specific properties required for their target application, but also offering multifunctionality, conformal integration in multiple surfaces and sustainability, in line with the European Green Deal goals. Metal oxides have been key materials for this end, finding applications from flexible electronics to photocatalysis and energy harvesting, with multicomponent materials as zinc tin oxide (ZTO) emerging as some of the most promising possibilities. This chapter is dedicated to the hydrothermal synthesis of ZTO nanostructures, expanding the already wide potential of ZnO. A literature review on the latest progress on the synthesis of a multitude of ZTO nanostructures is provided (e.g., nanowires, nanoparticles, nanosheets), emphasizing the relevance of advanced nanoscale techniques for proper characterization of such materials. The multifunctionality of ZTO will also be covered, with special attention being given to their potential for photocatalysis, electronic devices and energy harvesters

Microwave-Assisted Synthesis of Zn2SnO4 Nanostructures for Photodegradation of Rhodamine B under UV and Sunlight

Funding Information: This work is funded by National Funds through FCT—Portuguese Foundation for Science and Technology, Reference UIDB/50025/2020-2023. This work also received funding from the European Community’s H2020 program under grant agreement No. 716510 (ERC-2016-StG TREND) and No. 101008701 (EMERGE). Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.The contamination of water resources by pollutants resulting from human activities represents a major concern nowadays. One promising alternative to solve this problem is the photocatalytic process, which has demonstrated very promising and efficient results. Oxide nanostructures are interesting alternatives for these applications since they present wide band gaps and high surface areas. Among the photocatalytic oxide nanostructures, zinc tin oxide (ZTO) presents itself as an eco-friendly alternative since its composition includes abundant and non-toxic zinc and tin, instead of critical elements. Moreover, ZTO nanostructures have a multiplicity of structures and morphologies possible to be obtained through low-cost solution-based syntheses. In this context, the current work presents an optimization of ZTO nanostructures (polyhedrons, nanoplates, and nanoparticles) obtained by microwave irradiation-assisted hydrothermal synthesis, toward photocatalytic applications. The nanostructures’ photocatalytic activity in the degradation of rhodamine B under both ultraviolet (UV) irradiation and natural sunlight was evaluated. Among the various morphologies, ZTO nanoparticles revealed the best performance, with degradation > 90% being achieved in 60 min under UV irradiation and in 90 min under natural sunlight. The eco-friendly production process and the demonstrated ability of these nanostructures to be used in various water decontamination processes reinforces their sustainability and the role they can play in a circular economy.publishersversionpublishe

Solution Combustion Synthesis of Hafnium-Doped Indium Oxide Thin Films for Transparent Conductors

2021.03825.CEECIND 951774 (FOXES, H2020-EIC-FETPROACT-2019)Indium oxide (In2O3)-based transparent conducting oxides (TCOs) have been widely used and studied for a variety of applications, such as optoelectronic devices. However, some of the more promising dopants (zirconium, hafnium, and tantalum) for this oxide have not received much attention, as studies have mainly focused on tin and zinc, and even fewer have been explored by solution processes. This work focuses on developing solution-combustion-processed hafnium (Hf)-doped In2O3 thin films and evaluating different annealing parameters on TCO’s properties using a low environmental impact solvent. Optimized TCOs were achieved for 0.5 M% Hf-doped In2O3 when produced at 400 °C, showing high transparency in the visible range of the spectrum, a bulk resistivity of 5.73 × 10−2 Ω.cm, a mobility of 6.65 cm2/V.s, and a carrier concentration of 1.72 × 1019 cm−3. Then, these results were improved by using rapid thermal annealing (RTA) for 10 min at 600 °C, reaching a bulk resistivity of 3.95 × 10−3 Ω.cm, a mobility of 21 cm2/V.s, and a carrier concentration of 7.98 × 1019 cm−3, in air. The present work brings solution-based TCOs a step closer to low-cost optoelectronic applications.publishersversionpublishe