NanoSERS Microfluidics platform for rapid screening for infectious diseases

Early and accurate disease detection is critical for clinical diagnosis and ultimately determining patient outcomes. Point-of-care testing (POCT) platforms are needed in low- resource settings and also to help the decentralisation of healthcare centres. Immunoas- says using Surface-Enhanced Raman Spectroscopy (SERS) are especially interesting for their increased sensitivity and specificity. Additionally, SERS can be easily translated into POCT formats with microfluidics. In this work, a sensitive, selective, capable of multiplexing, and reusable SERS-based biosensor was developed. The SERS immunoas- say relies on a sandwich format, whereby a capture platform and SERS immunotags can capture and detect a specific antigen, respectively. The SERS immunotags consisted of gold nanostars, allowing exceptionally intense SERS signals from attached Raman re- porters, and the covalent attachment of antibodies provided a stable antigen-antibody binding activity. As a capture platform, a regenerated cellulose-based hydrogel provided a robust design and the added advantage of environmental friendliness. Besides being a transparent material with low background fluorescence and Raman signal, its high-water retention capacity was particularly suited for preserving the high activity of covalently bound antibodies, improving the assay time-stability. This SERS-based immunoassay was then integrated into a microfluidic device, allowing high-throughput sample screening allied with the high sensitivity and multiplexing features of the developed assay. The de- vice was fabricated in less than 30 minutes by exploring direct patterning on shrinkable polystyrene sheets for the construction of adaptable complex three-dimensional microflu- idic chips. Finally, to validate the microfluidic system, Plasmodium falciparum infected red blood cell culture samples were tested for malaria biomarker detection. The discrimi- nation of SERS immunotags signals from the background was made through the direct classical least squares method. As a result, better data fitting was achieved, compared to the commonly used peak integral method. Considering these features, the proposed SERS-based immunoassay notably improved the detection limits of traditional enzyme- linked immunosorbent assay approaches. Its performance was better or comparable to existing SERS-based immunosensors. Moreover, this approach successfully overcame the main challenges for application at POCT, including increasing reproducibility, sensitivity, and specificity. Hence, the microfluidic SERS system represents a powerful technology which can contribute to early diagnosis of infectious diseases, a decisive step towards lowering their still substantial burden on health systems worldwide.A detecção precoce e precisa de doenças é fundamental para o diagnóstico clínico de- terminando frequentemente o prognóstico do paciente. Desta forma, plataformas de teste de rastreio (conhecidos pelo acrónimo de POCT) são extremamente necessárias, não só em locais com poucos recursos, mas também para ajudar à descentralização dos cuidados de saúde. Os ensaios imunológicos que utilizam a espectroscopia de Raman aumentada pela superfície (conhecida pelo acrónimo de SERS) são particularmente interessantes pela sua elevada sensibilidade. Além disso, os ensaios em SERS podem ser facilmente convertidos para formatos POCT quando combinados com microfluídica. Este trabalho consistiu no desenvolvimento de um biosensor sensível, selectivo, capaz de múltipla detecção e reuti- lizável baseado no fenómeno de SERS. O ensaio imunológico em SERS foi realizado num formato em sanduíche onde um antigénio específico é apreendido por uma plataforma de captura e reconhecido por imunosondas activas em SERS. Estas sondas consistem em nanopartículas de ouro em forma de estrela, que proporcionam um sinal de SERS intenso proveniente das moléculas repórter de Raman ligadas às nanopartículas. As sondas ad- quirem a especificidade necessária para o antigénio de anticorpos a elas ligados de forma covalente, e, por conseguinte, permitem uma ligação estável antigénio-anticorpo. O hidro- gel regenerado à base de celulose forneceu uma plataforma de captura de design robusto e ecológico. Além de ser um material transparente com baixa fluorescência e, portanto, de baixa interferência no sinal de Raman, é um material com uma elevada capacidade de retenção de água tornando-o particularmente adequado para preservar a actividade dos anticorpos ligados covalentemente. Deste modo, o hidrogel proporciona uma plataforma de captura estável ao longo do tempo. O immunoensaio baseado em SERS desenvolvido foi posteriormente integrado num dispositivo de microfluídica, permitindo analisar um grande número de amostras sendo simultaneamente sensível e passível para aplicações de análise de múltiplos antigénios. O dispositivo foi fabricado em menos de 30 minu- tos devido à padronização directa em folhas de poliestireno contrácteis possibilitando a construção tridimensional de um dispositivo de microfluídica. Finalmente, para validar o sistema de microfluídica, amostras de cultura de eritrócitos infectados com Plasmodium falciparum foram testadas para detecção de biomarcadores de malária. A discriminação dos sinais das immunosondas activas em SERS, relativamente a sinais interferentes, foi feita através do método clássico de quadrados mínimos. Como resultado, foi conseguido um melhor ajuste de dados em comparação com o método de cálculo do integral das áreas das bandas habitualmente utilizado. Assim, o ensaio imunológico baseado em SERS proposto neste trabalho permitiu obter um limite de detecção mais baixo do que o obtido pelas abordagens tradicionais como o ensaio de imunoabsorção enzimática (conhecido pelo acrónimo de ELISA), além de exibir um desempenho melhor ou comparável a ou- tros sensores baseados em SERS já existentes na literatura. Adicionalmente, o sistema desenvolvido neste trabalho permite ultrapassar desafios que impedem a utilização deste tipo de sensores em locais de poucos recursos, apresentando valores elevados de repro- dutibilidade, sensibilidade e especificidade. Por conseguinte, um sistema que combina SERS e microfluídica representa uma tecnologia potencialmente importante na detecção precoce, na esperança de que, num futuro próximo, as consequências das doenças infecci- osas que ainda impõem um fardo substancial ao sistema de saúde a nível mundial, sejam minoradas

Plasmonic substrates for ultrasensitive surface-enhanced Raman spectroscopy: application to the detection of food toxins

The food contaminants consist in chemical substances in food products. The contaminants include for example, pesticides, antibiotics, and toxins. Recently there has been an increasing concern in detection of such contaminants not only for the prevention of public health, but also of the environment. The currently available methods for detection of chemicals in foods are time consuming, expensive and complex to operate. Hence, is necessary to development other methods to overcome the aforementioned disadvantages. The main objective of this work was to explore the feasibility of surface-enhanced Raman spectroscopy (SERS) as a sensitive, robust, simple and fast technique for the detection of food contaminants. Therefore, two different types of SERS substrate were developed. One of the substrates had paper as solid support matrix, with wells enclosed by hydrophobic barriers (two paper types were studied, chromatography and office). Nanoparticles (NPs) of silver, spherical and star-shaped, were chemically synthesized and deposited in the wells by drop-casting. The SERS efficiency study highlighted the office paper as the most appropriate support, due to the greater retention of NPs in star-shape on its surface. The detection limit values (LOD) and quantitation (LOQ) for rhodamine 6G (R6G) were 0.17±0.04 and 2.5±0.5 ppb, respectively. This substrate has proven reproducible and stable over time (5 weeks) with relative standard deviations (RSD) of 1.7 % and 7.3 %, respectively. The second substrate was made by physical vapor deposition (PVD) allowing a layer of spherical NPs. The LOD and LOQ values for R6G were 0.015±0.002 and 1.1±0.2 ppb, respectively. The proof-of-concept study was conducted with malathion and domoic acid (DA) and was not possible to detect DA. However, the LOD and LOQ for malathion in paper SERS substrate were ≈3944 and ≈1652 ppm respectively, and for the PVD substrate were, ≈925 and ≈5644 ppm, respectively. Both SERS substrates and their production method, were sensitive, robust, and inexpensive, allowing the rapid detection of analytes

Do experiential posts increase consumer engagement on instagram? : exploring the effect of vividness and emotional appeal on experiential posts’ consumer engagement

From beauty, to automotive, to technology and fashion industries we have been witnessed an increasingly adoption of strategies anchored on Experiential Marketing along with lifestyle branding on Social Media. Hence, the aim of this research is to analyze whether experiential posts increase consumer brand engagement on Instagram, when comparing to more functional posts, and study the effect of characteristics vividness and emotional appeal on experiential posts’ consumer engagement. In order to achieve this purpose, 120 brand posts, half experiential and half functional, characterized based on a relevant study, were collected from 15 Instagram brands’ pages and respectively number of likes, comments and followers were compiled in order to calculate consumer engagement. Additionally, both characteristics of interest were identified at an individual experiential post level. Notwithstanding, results encourage us to accept that functional posts lead to higher levels of consumer engagement on Instagram than experiential posts. Though, a low level of vividness (i.e. images) and the presence of high emotional appeal on experiential posts will lead to higher consumer engagement. All in all, this study provides valuable insights regarding Social Media and consumer engagement which can help marketers build their Instagram strategies more cautiously.Da indústria da beleza, à automóvel, à tecnologia passando pela moda, temos presenciado uma crescente adoção de estratégias assentes no Marketing Experiencial e no “lifestyle branding” nas Redes Sociais. Desta forma, o objetivo desta pesquisa é analisar se os posts experienciais aumentam o envolvimento por parte dos consumidores com a marca no Instagram, em comparação com os posts mais funcionais e, adicionalmente, estudar o efeito das características “vividness” e “emotional appeal” no envolvimento dos consumidores com os posts experienciais. Para alcançar este objetivo, 120 posts, trinta experienciais e trinta funcionais categorizados tendo por base um estudo previamente selecionado, foram recolhidos de 15 perfis de Instagram e, o número de likes, comentários e followers foram compilados de forma a calcular a variável envolvimento dos consumidores. Adicionalmente, as duas características de interesse foram identificadas e categorizadas ao nível de cada post experiencial. Os resultados encorajam-nos a aceitar que os posts funcionais levam a níveis de envolvimento dos consumidores no Instagram superiores aos posts experienciais. Por sua vez, um mais baixo nível de “vividness” (ou seja, imagens) e a presença de elevado “emotional appeal” em posts experienciais levam a um maior envolvimento do consumidor. Concluindo, este estudo dispõe de vários conhecimentos e pistas valiosas em relação às Redes Sociais e ao envolvimento dos consumidores, sendo um importante ponto de partida para os marketers na construção de novas estratégias para o Instagram

O “novo papel comunicativo” do vitral na sociedade actual

In medieval times stained glass worked as an illustrated bible to an illiterate society. In the twentieth century, with the development of science and technology glass became even more versatile widely spread and insuperable from our society. Today we see an increase in the materialization of art. The development of technology and art techniques is closely linked with scientific development and with cultural relationships between people. Today’s stained glass has got a new status, a new communicative impact that assures its own place in contemporary art. Stained glass isn´t confined to sacred places any more, it works in public places such as court houses and hotels. The message is essentially aesthetic, in some cases creating an atmosphere and adding value to the place, in others, providing enjoyment of the art and in these situations stained glass is exhibited independent of the architecture and seen as a work of art in itself

A generalized clark-ocone formula

60H25 (60H07 60H40 60J55 60J65)We extend the Clark-Ocone formula to a suitable class of generalized Brownian functionals. As an example we derive a representation of Donsker's delta function as (limit of) a stochastic integral

Some observations on gold in the weathering profile at Garimpo Porquinho, an artisanal mine in the Tapajós Region, Brazilian Amazon

At Garimpo Porquinho (Tapajós Province, Brazilian Amazon) gold-bearing quartz veins containing sulfides occur in a narrow zone affected by hydrothermal alteration. The artisanally mined veins are exposed in a saprolite zone extending down at least 9 m to the fresh rock and are covered by a 1 m thick residual soil. Lateral gold dispersion in the saprolite is not noticeable whereas in the soil gold dispersion has been observed as far as 2 m from the vein. Trace metals associated with gold include Ag, Bi, As and Sb. Copper and lead, present in sulfides, can also indicate the presence of gold. The study of gold particles in different levels of the profile shows that gold has been affected by weathering. In the upper levels of the profile, particles are smaller, more rounded and pitted by dissolution. Grains of primary gold containing up to 20% Ag are commonly exhibit silver-poor rims which may penetrate deep into the grain. The interface between the Ag-poor rims and the interior is very sharp. Such gold-rich rims likely formed by self-electrorefining of electrum grains during weathering.No Garimpo Porquinho (Província Tapajós, Amazônia brasileira) veios de quartzo e sulfetos portadores de ouro ocorrem em uma zona estreita afetada por alteração hidrotermal. Sobre a mineralização primária ocorre uma cobertura de saprolito de cerca de 9 m de espessura, capeada por solo de 1 m de espessura. No saprolito não há dispersão lateral do ouro. No solo, no entanto, ocorre dispersão lateral do ouro até pelo menos 2 m a partir do veio. Os principais elementos farejadores são Ag, Bi, As e Sb. Cobre e chumbo, presentes nos sulfetos, podem também indicar a presença de ouro. O estudo das partículas de ouro em diferentes níveis do perfil de alteração mostrou que o ouro foi afetado pelo intemperismo. Nos níveis superiores do perfil as partículas são menores, possuem formas arredondadas e suas superfícies apresentam minúsculos orifícios característicos de dissolução. Observa-se que grãos de ouro primário (20% Ag) exibem comumente bordas empobrecidas em prata que podem penetrar fundo no grão. A interface entre as bordas empobrecidas em prata e o interior é brusca. A formação desses grãos pode ser atribuída ao processo de auto-refinamento eletrolítico dos grãos de electrum durante o intemperismo

Football manager-s turnover: a deep analysis based on empirical findings

A football manager's job is always under great scrutiny, as the pressure of good results from the fans, the management and the media create a high turnover ratio in this position. This paper tries to measure, from a sample of 208 experiences of coaches in 54 different European clubs if certain variables such as the presence in the European Competitions ,the Tier of the team or the timing (Midseason or not) of the sacking influence the job tenure of the manager and the short-term performance effect of the team after the sacking of a manager

A influência do paterfamilias na educação da elite política romana de finais da República: o exemplo de Marco Túlio Cícero

Tomando por fonte a vastíssima colecção de cartas escritas (e recebidas) por Cícero em meados do século I a.C., este estudo, que se centrará na análise de algumas das referências feitas pelo epistológrafo à educação e entrada na vida pública do filho, permitir-nos-á perceber em que medida o percurso educativo e a integração na vida pública do jovem aristocrata romano foram condicionados pela acção do paterfamilias

Degenerative joint disease : from a conservative to a minimally invasive approach : clinical case

Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio

Panorama da economia criativa no Brasil

The concept of Creative Economy and its establishment as a discipline of study gained relevance from the 2000s. Creative Economy is the set of economic activities that depend on the symbolic content - being creativity the more significant factor for the production of goods and services. The Creative Economy is closely related to economic, cultural and social factors that interact with technology and intellectual property. Thus, this paper presents different concepts and ways to measure the Creative Economy around the world, and then present a measurement of the Creative Economy in Brazil, both the formal and the informal. It is estimated that the wages Creative Economy represents between 1.2% and 2% of the Brazilian GDP and approximately 2% of the labor workforce and 2.5% of formal wages. Moreover, workers in the Creative Economy earn more and are more educated than average