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result(s) for
"Fernandes, P.A."
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On the identification of Sb2Se3 using Raman scattering
by
Vermang, B.
,
Correia, M.R.
,
Salomé, P.M.P.
in
Antimony compounds
,
Antimony trioxide
,
Biomaterials
2018
Robust evidences are presented showing that the Raman mode around 250 cm−1 in the Sb2Se3 thin films does not belong to this binary compound. The laser power density dependence of the Raman spectrum revealed the formation of Sb2O3 for high values of laser intensity power density excitation under normal atmospheric conditions. To complement this study, the Sb2Se3 films were characterized by x-ray diffraction during in situ annealing. Both these measurements showed that the Sb2Se3 compound can be replaced by Sb2O3. A heat-assisted chemical process explains these findings. Furthermore, Raman conditions required to perform precise measurements are described.
Journal Article
Sub-Bandgap Sensitization of Perovskite Semiconductors via Colloidal Quantum Dots Incorporation
2023
By taking advantage of the outstanding intrinsic optoelectronic properties of perovskite-based photovoltaic materials, together with the strong near-infrared (NIR) absorption and electronic confinement in PbS quantum dots (QDs), sub-bandgap photocurrent generation is possible, opening the way for solar cell efficiencies surpassing the classical limits. The present study shows an effective methodology for the inclusion of high densities of colloidal PbS QDs in a MAPbI3 (methylammonium lead iodide) perovskite matrix as a means to enhance the spectral window of photon absorption of the perovskite host film and allow photocurrent production below its bandgap. The QDs were introduced in the perovskite matrix in different sizes and concentrations to study the formation of quantum-confined levels within the host bandgap and the potential formation of a delocalized intermediate mini-band (IB). Pronounced sub-bandgap (in NIR) absorption was optically confirmed with the introduction of QDs in the perovskite. The consequent photocurrent generation was demonstrated via photoconductivity measurements, which indicated IB establishment in the films. Despite verifying the reduced crystallinity of the MAPbI3 matrix with a higher concentration and size of the embedded QDs, the nanostructured films showed pronounced enhancement (above 10-fold) in NIR absorption and consequent photocurrent generation at photon energies below the perovskite bandgap.
Journal Article
Environmental Ethics: Driving Factors Beneath Behavior, Discourse and Decision-Making
2016
This paper tries to characterize the factors determining human relations with its environment and to identify the drives of those behavioral patterns and “
praxis
”. One scrutinizes the physiological and psychological factors that influence those drives , and tries to determine ways of overriding instinctive drives in favor of rational, sustainable ones. It focuses its attention on the way the different ecosystemic, economic and socio-cultural systems work, and pin-points the critical issues in view of the development of sustainable behavioral patterns. Also the values that must build the new behavioral paradigm, as well as the ways to ensure the evolutionary quantum-leap necessary to ensure this sustainable condition, and the fulfilment, at every level, the different needs of humans and human societies, are analyzed. In conclusion, it stresses the fact that any reliable and long lasting change towards a sustainable behavior must start at the individual and the close social groups levels, and of the development of new factors of self-fulfillment and gratification, able to support and foster that change. The proposed epistemological approach is particularly innovative, precisely because of this emphasis on the individual drives and the way they determine the global patterns of environmental use, as well as the way they can evolve into a more rational (human) character. In short, the paper focuses itself in the way man can evolve from its natural animal instincts and drives toward more rational ones, humanizing its behavior and turning, therefore, into an able actor of the process of sustainability building.
Journal Article
Inhibition of caspase-1 or gasdermin-D enable caspase-8 activation in the Naip5/NLRC4/ASC inflammasome
by
Mascarenhas, Danielle P. A.
,
Cerqueira, Daiane M.
,
Castanheira, Fernanda V. S.
in
Animals
,
Apoptosis
,
Apoptosis Regulatory Proteins - antagonists & inhibitors
2017
Legionella pneumophila is a Gram-negative, flagellated bacterium that survives in phagocytes and causes Legionnaires' disease. Upon infection of mammalian macrophages, cytosolic flagellin triggers the activation of Naip/NLRC4 inflammasome, which culminates in pyroptosis and restriction of bacterial replication. Although NLRC4 and caspase-1 participate in the same inflammasome, Nlrc4-/- mice and their macrophages are more permissive to L. pneumophila replication compared with Casp1/11-/-. This feature supports the existence of a pathway that is NLRC4-dependent and caspase-1/11-independent. Here, we demonstrate that caspase-8 is recruited to the Naip5/NLRC4/ASC inflammasome in response to flagellin-positive bacteria. Accordingly, caspase-8 is activated in Casp1/11-/- macrophages in a process dependent on flagellin, Naip5, NLRC4 and ASC. Silencing caspase-8 in Casp1/11-/- cells culminated in macrophages that were as susceptible as Nlrc4-/- for the restriction of L. pneumophila replication. Accordingly, macrophages and mice deficient in Asc/Casp1/11-/- were more susceptible than Casp1/11-/- and as susceptible as Nlrc4-/- for the restriction of infection. Mechanistically, we found that caspase-8 activation triggers gasdermin-D-independent pore formation and cell death. Interestingly, caspase-8 is recruited to the Naip5/NLRC4/ASC inflammasome in wild-type macrophages, but it is only activated when caspase-1 or gasdermin-D is inhibited. Our data suggest that caspase-8 activation in the Naip5/NLRC4/ASC inflammasome enable induction of cell death when caspase-1 or gasdermin-D is suppressed.
Journal Article
Impact of climate change and social determinants on the spatial and epidemiological distribution of tuberculosis in the state of Pará: a perspective for COP 30
by
Tavares-Cohén, G.A.
,
Mendonça-Cavalcante, P.A
,
Brito-Alves, B.C.
in
BIOLOGY
,
Brazil - epidemiology
,
Climate Change
2025
Abstract Tuberculosis is a critical public health challenge in Brazil, with the state of Pará reporting high incidence rates driven by social inequalities, rapid urbanization, and adverse climatic conditions. This study analyzes the epidemiology of tuberculosis in the Metropolitan Region of Belém from 2018 to 2022, correlating social and environmental determinants with the impacts of climate change. Georeferenced data, temporal analysis, and predictive modeling were employed to identify epidemiological patterns and high-incidence clusters. Belém accounted for 60.1% of cases in the region, highlighting the influence of population density and socioeconomic vulnerabilities exacerbated by extreme climatic events. The findings underscore the need to integrate public policies and sustainability, emphasizing COP30 as an opportunity to catalyze both local and global actions. Resumo Tuberculose é um desafio crítico para a saúde pública no Brasil, com o estado do Pará apresentando altas taxas de incidência relacionadas a desigualdades sociais, urbanização acelerada e condições climáticas adversas. Este estudo analisa a epidemiologia da tuberculose na Região Metropolitana de Belém entre 2018 e 2022, correlacionando determinantes sociais, ambientais e os impactos das mudanças climáticas. Foram utilizados dados georreferenciados, análise temporal e modelagem preditiva para identificar padrões epidemiológicos e clusters de alta incidência. Belém concentrou 60,1% dos casos na região, destacando a influência de densidade populacional e vulnerabilidades socioeconômicas, exacerbadas por eventos climáticos extremos. Os resultados reforçam a necessidade de integrar políticas públicas e sustentabilidade, destacando a COP30 como oportunidade para catalisar ações locais e globais.
Journal Article
Vertical stratification of insect abundance and species richness in an Amazonian tropical forest
by
Fachin, Diego Aguilar
,
Frare, Livia Maria
,
Mello-Patiu, Cátia
in
631/158/2450
,
631/158/857
,
631/181
2022
Tropical forests are among the most biodiverse biomes on the planet. Nevertheless, quantifying the abundance and species richness within megadiverse groups is a significant challenge. We designed a study to address this challenge by documenting the variability of the insect fauna across a vertical canopy gradient in a Central Amazonian tropical forest. Insects were sampled over two weeks using 6-m Gressitt-style Malaise traps set at five heights (0 m–32 m–8 m intervals) on a metal tower in a tropical forest north of Manaus, Brazil. The traps contained 37,778 specimens of 18 orders of insects. Using simulation approaches and nonparametric analyses, we interpreted the abundance and richness of insects along this gradient. Diptera, Hymenoptera, and Coleoptera had their greatest abundance at the ground level, whereas Lepidoptera and Hemiptera were more abundant in the upper levels of the canopy. We identified species of 38 of the 56 families of Diptera, finding that 527 out of 856 species (61.6%) were not sampled at the ground level. Mycetophilidae, Tipulidae, and Phoridae were significantly more diverse and/or abundant at the ground level, while Tachinidae, Dolichopodidae, and Lauxaniidae were more diverse or abundant at upper levels. Our study suggests the need for a careful discussion of strategies of tropical forest conservation based on a much more complete understanding of the three-dimensional distribution of its insect diversity.
Journal Article
Single and ensemble classifiers for defect prediction in sheet metal forming under variability
by
Ribeiro, B. M.
,
Oliveira, M. C.
,
Fernandes, J. V.
in
Artificial Intelligence
,
Classifiers
,
Computational Biology/Bioinformatics
2020
This paper presents an approach, based on machine learning techniques, to predict the occurrence of defects in sheet metal forming processes, exposed to sources of scatter in the material properties and process parameters. An empirical analysis of performance of ML techniques is presented, considering both single learning and ensemble models. These are trained using data sets populated with numerical simulation results of two sheet metal forming processes: U-Channel and Square Cup. Data sets were built for three distinct steel sheets. A total of eleven input features, related to the mechanical properties, sheet thickness and process parameters, were considered; also, two types of defects (outputs) were analysed for each process. The sampling data were generated, assuming that the variability of each input feature is described by a normal distribution. For a given type of defect, most single classifiers show similar performances, regardless of the material. When comparing single learning and ensemble models, the latter can provide an efficient alternative. The fact that ensemble predictive models present relatively high performances, combined with the possibility of reconciling model bias and variance, offer a promising direction for its application in industrial environment.
Journal Article
Numerical study on the effect of mechanical properties variability in sheet metal forming processes
by
Oliveira, M. C.
,
Fernandes, J. V.
,
Prates, P. A.
in
Anisotropy
,
Blankholders
,
CAE) and Design
2018
This work presents a numerical study on the influence of variability in the mechanical properties of metal sheets in predicting the occurrence of springback and maximum thinning, for a sheet metal forming process. For this purpose, a mild steel was selected as reference material and the U-channel forming process was considered. The factors selected for this variability study were Young’s modulus, the isotropic hardening law parameters, the anisotropy coefficients and the initial thickness of the sheet metal. The variability of all factors was described by a probabilistic normal distribution, with well-defined mean and standard deviation values. Firstly, one-factor-at-a-time, 1/16th fractional factorial and Plackett-Burman screening designs were tested, using FEA results of the U-channel forming process, at two levels of blank-holder force. Sensitivity studies based on analysis of main effects, index of influence and variance (ANOVA) were performed, for each screening design approach, to identify the most relevant factors concerning the occurrence of springback and maximum thinning in the forming process. The comparison between the different screening design approaches indicates that they can lead to similar results, or to the selection of different factors, depending on the sensitivity analysis procedure selected to determine the most relevant factors. Then, metamodels were established using the most relevant factors to build the response surfaces, i.e. analytical relationships between the identified relevant factors and the responses (springback and maximum thinning); consequently, the responses variability can be expeditiously evaluated.
Journal Article
The Role of SLC22A1 and Genomic Ancestry on Toxicity during Treatment in Children with Acute Lymphoblastic Leukemia of the Amazon Region
by
Santos, Ney P. C. dos
,
Cohen-Paes, Amanda de N.
,
Modesto, Antônio A. C.
in
Acute lymphoblastic leukemia
,
Adolescent
,
Blacks
2022
In Brazil, Acute lymphoid leukemia (ALL) is the leading cause of cancer deaths in children and adolescents. Treatment toxicity is one of the reasons for stopping chemotherapy. Amerindian genomic ancestry is an important factor for this event due to fluctuations in frequencies of genetic variants, as in the NUDT15 and SLC22A1 genes, which make up the pharmacokinetic and pharmacodynamic pathways of chemotherapy. This study aimed to investigate possible associations between NUDT15 (rs1272632214) and SLC22A1 (rs202220802) gene polymorphism and genomic ancestry as a risk of treatment toxicities in patients with childhood ALL in the Amazon region of Brazil. The studied population consisted of 51 patients with a recent diagnosis of ALL when experiencing induction therapy relative to the BFM 2009 protocol. Our results evidenced a significant association of risk of severe infectious toxicity for the variant of the SLC22A1 gene (OR: 3.18, p = 0.031). Genetic ancestry analyses demonstrated that patients who had a high contribution of African ancestry had a significant protective effect for the development of toxicity (OR: 0.174; p = 0.010), possibly due to risk effects of the Amerindian contribution. Our results indicate that mixed populations with a high degree of African ancestry have a lower risk of developing general toxicity during induction therapy for ALL. In addition, individuals with the SLC22A1 variant have a higher risk of developing severe infectious toxicity while undergoing the same therapy.
Journal Article
An appraisal of biological responses and network of environmental interactions in non-mining and mining impacted coastal waters
by
Das, Anindita
,
Gonsalves, Maria Judith
,
Jineesh, V. K.
in
Anthropogenic factors
,
Aquatic Pollution
,
Atmospheric Protection/Air Quality Control/Air Pollution
2015
The coastal waters of Goa and Ratnagiri lying on the West coast of India are influenced by terrestrial influx. However, Goa is influenced anthropogenically by iron-ore mining, while Ratnagiri is influenced by deposition of heavy minerals containing iron brought from the hinterlands. We hypothesize that there could be a shift in biological response along with changes in network of interactions between environmental and biological variables in these mining and non-mining impacted regions, lying 160 nmi apart. Biological and environmental parameters were analyzed during pre-monsoon season. Except silicates, the measured parameters were higher at Goa and related significantly, suggesting bacteria centric, detritus-driven region. At Ratnagiri, phytoplankton biomass related positively with silicate suggesting a region dominated by primary producers. This dominance perhaps got reflected as a higher tertiary yield. Thus, even though the regions are geographically proximate, the different biological response could be attributed to the differences in the web of interactions between the measured variables.
Journal Article