683 research outputs found

    Electrochemical and electrochromic properties of poly(4,4 dimethoxy 3'-methyl 2,2':5',2 terthiophene)

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    This work describes the electrochemical, spectroelectrochemical and electrochromic properties of poly(4,4 dimethoxy 3'-methyl 2,2':5',2 terthiophene) thin films. The effect of temperature on the electropolymerization was studied by cyclic voltammetry measured in situ. The temperatures used were -10, 0, 10, 20, and 40 ºC. Results indicate that the electropolymerization temperature directly affect the degree of chain organization. The optical response time for bleaching was 0.8 s and for coloring 0.3 s (for films synthesized at 40 ºC, 60 nm thick). After 1400 electrochromic cycles, the chromatic contrast at 570 nm changes from 31 to 14%. The coloration efficiency was enhanced as a function of redox cycling. This was probably caused by a decrease in the injected charge necessary for the color change, suggesting that the electroactive losses occurring during the cycles are related to sites not responsible for electrochromic contrast.Este trabalho descreve o estudo das propriedades eletroquímicas, espectroeletroquímicas e eletrocrômicas de filmes finos de poli(4,4 dimetoxi 3'-metil 2,2':5',2 tertiofeno). A voltametria cíclica in situ foi usada para estudar o efeito da temperatura sobre a eletropolimerização. As temperaturas utilizadas na deposição eletroquímica foram -10, 0, 10, 20 e 40 ºC. Os resultados indicaram que a temperatura de eletropolimerização afeta diretamente o grau de ordenamento molecular do polímero. O tempo de resposta eletrocrômico foi de 0,8 s para clareamento e 0,3 s para escurecimento (para filmes sintetizados a 40 ºC, espessura de 60 nm). Após 1400 ciclos eletrocrômicos, o contraste óptico a 570 nm diminuiu de 31 para 14%. A eficiência eletrocrômica foi intensificada em função do número de ciclos eletrocrômicos. Este fato foi provavelmente causado pela diminuição da carga injetada, necessária para a mudança de cor, sugerindo que as perdas na eletroatividade estão associadas a sítios que não são responsáveis pela mudança de coloração.733738Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

    Catalytic reutilization of chromium-loaded NaY oxidation of ethyl acetate

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    EUROPACAT IX - Catalysis for a Sustainable WorldThe aim of this study is the reutilization of new materials obtained by biorecovery of chromium from water, in catalytic oxidations of volatile organic compounds. A biosorption system consisting of a microorganism supported on a NaY zeolite was used to remove hexavalent chromium from contaminated water. After the biosorption process, the chromium-loaded zeolite was used as catalyst to be applied in catalytic oxidation of ethyl acetate. The results showed that a higher content of chromium enhanced the activity and the C0 2 selectivity of the catalystinfo:eu-repo/semantics/publishedVersio

    Predictive Maintenance Model Based on Anomaly Detection in Induction Motors: A Machine Learning Approach Using Real-Time IoT Data

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    With the support of Internet of Things (IoT) devices, it is possible to acquire data from degradation phenomena and design data-driven models to perform anomaly detection in industrial equipment. This approach not only identifies potential anomalies but can also serve as a first step toward building predictive maintenance policies. In this work, we demonstrate a novel anomaly detection system on induction motors used in pumps, compressors, fans, and other industrial machines. This work evaluates a combination of pre-processing techniques and machine learning (ML) models with a low computational cost. We use a combination of pre-processing techniques such as Fast Fourier Transform (FFT), Wavelet Transform (WT), and binning, which are well-known approaches for extracting features from raw data. We also aim to guarantee an optimal balance between multiple conflicting parameters, such as anomaly detection rate, false positive rate, and inference speed of the solution. To this end, multiobjective optimization and analysis are performed on the evaluated models. Pareto-optimal solutions are presented to select which models have the best results regarding classification metrics and computational effort. Differently from most works in this field that use publicly available datasets to validate their models, we propose an end-to-end solution combining low-cost and readily available IoT sensors. The approach is validated by acquiring a custom dataset from induction motors. Also, we fuse vibration, temperature, and noise data from these sensors as the input to the proposed ML model. Therefore, we aim to propose a methodology general enough to be applied in different industrial contexts in the future

    Transforming orange waste with yeasts: bioprocess prospects

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    Para tornar a economia circular uma realidade, é obrigatório desenvolver formas de transformar resíduos em produtos de valor. Nesse contexto, investigar o potencial biotecnológico de diferentes resíduos é bastante desejável. Esta revisão analisa como os resíduos de laranja podem ser usados como matéria-prima de biorrefinaria para produzir diferentes bioprodutos utilizando leveduras como principais biocatalisadores. Além do mercado atual da laranja, a biomassa da fruta, rica em pectina, é descrita detalhadamente, visando elucidar como as células de levedura podem convertê-la em etanol, xilitol, polifenóis e ácidos orgânicos (alguns deles, compostos voláteis). As engenharias genética, metabólica e evolutiva também são analisadas como ferramentas biotecnológicas para melhorar os processos já existentes. Finalmente, esta revisão também aborda o potencial emprego de leveduras isoladas de frutas no biorrefinamento de biomassas ricas em pectina, como resíduos de laranja. Todos os dados aqui apresentados levam à conclusão de que esses resíduos já poderiam estar sendo aproveitados para fins nobres.It is mandatory to make the circular economy a reality, developing ways of transforming waste into valuable products. In this context, investigating the biotechnological potential of different residues is most welcome. This review analyzes how orange waste can be used as biorefinery feedstock to produce different bioproducts using yeasts as the major biocatalysts. In addition to the current orange market, its pectin-rich biomass is described in detail, aiming to elucidate how yeast cells can convert it into ethanol, xylitol, polyphenols, and organic acids (some of them, volatile compounds). Genetic, metabolic, and evolutionary engineering are also analyzed as biotechnological tools to improve the existing processes. Finally, this review also addresses the potential employment of fruit-dwelling yeasts in biorefining pectin-rich biomasses such as orange wastes. All the data presented herein lead to the conclusion that these residues could already be used for noble purposes

    Reactivity of 5a,6-anhydrotetracycline platinum(II) complex with biological nucleophiles: a theoretical study

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    This paper describes a theoretical analysis of the interaction between 5a,6-anhydrotetracycline platinum(II) complex (AHTC-Pt) and some biological nucleophiles; adenine (A), guanine (G), cysteine (Cys) and methionine (Met). The aquated species [Pt(AHTC)Cl(H2O)]+ was taken as reagent for the processes studied here. For DNA bases (A and G), the calculated values for ΔGa,aq at the B3LYP/6-311+G(2d,p) level were 21.7 and 20.7 kcal mol-1 for interaction with A and G, respectively, which are in accordance with the expected behavior of faster process involving G. These values are higher than the experimental activation energy for the parent compound cisplatin (18.5 kcal mol-1 for interaction with G). For the process involving the amino-acids, the barriers were 17.6 (Cys) and 18.5 kcal mol-1 (Met), which are lower than the observed values for cisplatin (20.5 and 20.2 kcal mol-1, respectively). These outcomes show that AHTC-Pt hybrid complex may be considered a promising lead compound in the development of novel anticancer drugs based on platinum complex

    Revealing a novel Otubain-Like Enzyme from Leishmania infantum with deubiquitinating activity toward K48-linked substrate

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    Deubiquitinating enzymes (DUBs) play an important role in regulating a variety of eukaryotic processes. In this context, exploring the role of deubiquitination in Leishmania infantum could be a promising alternative to search new therapeutic targets for leishmaniasis. Here we present the first characterization of a DUB from L. infantum, otubain (OtuLi), and its localization within parasite. The recombinant OtuLi (rOtuLi) showed improved activity on lysine 48 (K48)-linked over K63-linked tetra-ubiquitin (Ub) and site-directed mutations on amino acids close to the catalytic site (F82) or involved in Ub interaction (L265 and F182) caused structural changes as shown by molecular dynamics, resulting in a reduction or loss of enzyme activity, respectively. Furthermore, rOtuLi stimulates lipid droplet biogenesis (an inflammatory marker) and induces IL-6 and TNF-a secretion in peritoneal macrophages, both proinflammatory cytokines. Our findings suggest that OtuLi is a cytoplasmic enzyme with K48-linked substrate specificity that could play a part in proinflammatory response in stimulated murine macrophages
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