Carbon dots from tryptophan doped glucose for peroxynitrite sensing

Tryptophan doped carbon dots (Trp-CD) were microwave synthesized. The optimum conditions of synthesizing of the Trp-CD were established by response surface multivariate optimization methodologies and were the following: 2.5 g of glucose and 300 mg of tryptophan diluted in 15 mL of water exposed for 5 min to a microwave radiation of 700 W. Trp-CD have an average size of 20 nm, were fluorescent with a quantum yield of 12.4% and the presence of peroxynitrite anion (ONOO−) provokes quenching of the fluorescence. The evaluated analytical methodology for ONOO− detection shows a linear response range from 5 to 25 μM with a limit of detection of 1.5 μM and quantification of 4.9 μM. The capability of the ONOO− quantification was evaluated in standard solutions and in fortified serum samples

Time dependent clustering of time series

In this work we consider the problem of clustering time series. Contrary to other works on this topic, our main concern is to let the most important observations, for instance the most recent, have a larger weight on the analysis. This is done by defining similarities measures between two time series, based on Pearson's correlation coefficient, which uses the notion of weighted mean and weighted covariance, where the weights increase monotonically with the time. We use these measures, which are metrics between time series, as a similarity or dissimilarity index between the $n$ time series to be clustered. We apply a very well known partitional method, the K-means, with some adaptations to make it able to choose the number of clusters

Um Modelo para Construção, Acompanhamento e Avaliação de Desenho Instrucional para a EaD – a Estratégia dos 4Cs

Existem inúmeras propostas de aprendizagem on-line e diversos paradigmas educacionais, que, se considerados na totalidade, oferecem uma visão complexa, por vezes confusa ou distorcida da realidade. Este trabalho propõe um modelo simplificador de desenho instrucional direcionado para EaD, baseado em quatro pilares ou ações principais (os 4Cs): Contexto, Conteúdo, Comunidade e Coordenação. Para cada uma das ações, há atores correspondentes que participam do caminho de construção, acompanhamento e avaliação e devem responder colaborativamente a quatro perguntas fundamentais: "como", "o quê", "com quem" e "por quê". Quanto maior o discernimento dos papeis e de sua ação, melhor a visão do processo educacional e de seu constante aperfeiçoamento. Este modelo foi aplicado ao curso "Química e os Sentidos - paladar e olfato", oferecido pela Diretoria de Extensão da Fundação CECIERJ e demonstrou resultados satisfatórios

Utilização de nanopartículas de TIO2 para o desenvolvimento de pavimentos rodoviários com capacidade fotocatalítica

A utilização de nanomateriais na indústria de construção rodoviária representa uma opção estrategicamente inovadora que visa a modificação dos materiais convencionais. Neste âmbito, dotar a superfície dos pavimentos rodoviários de capacidade fotocatalítica contribuirá para efetuar a despoluição do ar e a redução da sujidade adsorvida nestas superfícies, aumentando a segurança rodoviária uma vez que minimiza a presença de óleos e gorduras adsorvidos pelas mesmas. Neste trabalho, misturas asfálticas convencionais foram modificadas pela adição de nanopartículas de TiO2 através de dois processos diferentes: inclusão em volume e por aspersão superficial de uma solução aquosa de nanopartículas de TiO2. As misturas asfálticas foram caracterizadas quimicamente e a sua morfologia e capacidade fotocatalítica foram avaliadas. Os resultados obtidos demonstram que a utilização de nanopartículas de TiO2 (aplicadas na superfície pela técnica de aspersão) permitiu obter misturas asfálticas com elevada capacidade fotocatalítica, já que o rendimento de fotodegradação foi superior a 50%.FEDE

Rhinovirus C and Respiratory Exacerbations in Children with Cystic Fibrosis

To investigate a possible role for human rhinovirus C in respiratory exacerbations of children with cystic fibrosis, we conducted microbiologic testing on respiratory specimens from 103 such patients in São Paulo, Brazil, during 2006–2007. A significant association was found between the presence of human rhinovirus C and respiratory exacerbations

Avaliar a compreensão do conceito de interações intermoleculares, através de vídeo aula, de alunos do primeiro ano do Ensino Médio em uma unidade escolar no estado do Rio de Janeiro.

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Hierarchical HRP-crosslinked silk fibroin/ZnSr-doped TCP nancocomposites towards osteochondral tissue regeneration: Biomechanical performance and in vivo assessment

[Excerpt] Introduction. Recent investigations highlight promising regenerative strategies for osteochondral (OC) tissue treatment, such as hierarchical nanocomposite scaffolds containing ionic dopants.1,2 They allow cell infiltration and ECM formation throughout the engineered cartilage and subchondral tissues. The biomechanical behavior, antibacterial properties, and in vivo performance of hierarchical nanostructures combining enzymatically crosslinked silk fibroin (SF) and ZnSr-doped β-tricalcium phosphate (ZnSrTCP) for OC tissue regeneration is herein assessed. [...]Thanks to the Portuguese Foundation for Science and Technology for M-era-Net/0001/2014 project, and for the distinctions (IF/01285/2015) and (CEECIND/03673/2017)

Coaxial fibres incorporated with phase change materials for thermoregulation applications

Nowadays, the growing concern about improving thermal comfort in different structures (textiles, buildings, and pavements, among others) has stimulated research into phase change materials (PCMs). The direct incorporation of PCMs into composite materials can cause mechanical impacts. Therefore, this study focuses on the design of phase change coaxial fibres (PCFs), using commercial cellulose acetate (CA) or recycled CA obtained from cotton fabrics (CAt) as the sheath and polyethylene glycol (PEG) 2000 as the core, via the wet spinning method; the fibres vary in molecular weight, concentration and ejection velocity. The fibres were assessed for their optical, chemical, thermal, and mechanical properties. The presence of PEG2000 is confirmed in the core of the fibres. Thermal analyses revealed a mass loss at high temperatures, attributable to the presence of PEG2000. Notably, the fibres with CA (Mn 30,000) showed superior thermal and mechanical performance. The melting point of PEG2000 incorporated into these PCFs coincided with the melting point of pure PEG2000 (about 55 °C), with a slight deviation, indicating that PCFs were obtained. Finally, the results point to the application of the fibres in civil engineering materials requiring a phase change between 50 and 60 °C, providing promising prospects for their use in applications requiring thermoregulatory properties.This research was funded by the Portuguese Foundation for Science and Technology (FCT) under the projects MicroCoolPav EXPL/EQUEQU/1110/2021 and NanoAir PTDC/FISMAC/6606/2020 (https://doi.org/10.54499/PTDC/FIS-MAC/6606/2020) and within the framework of Strategic Funding UIDB/04650/2020, UIDB/04029/2020 (https://doi.org/10.54499/UIDB/04029/2020) and UID/QUI/0686/2020. I.R.S. and H.P.F. would like to thank FCT for their funding contracts 2022.00763.CEECIND (https://doi.org/10.54499/2022.00763.CEECIND/CP1718/CT0006) and 2021.02720.CEECIND (https://doi.org/10.54499/DL57/2016/CP1377/CT0098)

Photocatalytic performance of textiles coated with TiO2-RGO system for degradation of crude petroleum under similar solar irradiation

The pollution caused by oil and its toxic derivatives presents a considerable risk to the public health and the environment. Here, we studied the influence of TiO2 nanoparticles immobilized on three types of textiles materials (Cotton, Entretela and PLA) coated with reduced graphene oxide (RGO) to be used for degradation of crude petroleum under simulated solar irradiation. The morphological studies of the functionalized textiles substrates were performed by using Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy, which indicated an excellent dispersion and adhesion of nanoparticles on the textile fibres covered with RGO. Ultraviolet–visible Diffuse Reflectance spectra suggests a reduction in the band gap energy of TiO2 due to the presence of RGO. The excitation/emission Synchronized Fluorescence and Fourier transform Infrared spectroscopies demonstrated that the functionalized textiles substrates exhibit a great potential for photocatalytic degradation of organic compounds with high prospects in petroleum and wastewater treatment areas