683 research outputs found
Electrochemical and electrochromic properties of poly(4,4 dimethoxy 3'-methyl 2,2':5',2 terthiophene)
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 eletroquÃmicas, espectroeletroquÃmicas e eletrocrômicas de filmes finos de poli(4,4 dimetoxi 3'-metil 2,2':5',2 tertiofeno). A voltametria cÃclica in situ foi usada para estudar o efeito da temperatura sobre a eletropolimerização. As temperaturas utilizadas na deposição eletroquÃmica foram -10, 0, 10, 20 e 40 ºC. Os resultados indicaram que a temperatura de eletropolimerização afeta diretamente o grau de ordenamento molecular do polÃmero. 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 sÃtios que não são responsáveis pela mudança de coloração.733738Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de NÃvel Superior (CAPES
Catalytic reutilization of chromium-loaded NaY oxidation of ethyl acetate
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
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
Para tornar a economia circular uma realidade, é obrigatório desenvolver formas de transformar resÃduos em produtos de valor. Nesse contexto, investigar o potencial biotecnológico de diferentes resÃduos é bastante desejável. Esta revisão analisa como os resÃduos 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 resÃduos de laranja. Todos os dados aqui apresentados levam à conclusão de que esses resÃduos 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
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
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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