The yellow fever virus (YFV) epidemic in Brazil is the largest in decades. The recent discovery of YFV in Brazilian
species mosquitos highlights a need to monitor the risk of reestablishment of urban ...YFV transmission in the Americas. We use a suite of epidemiological, spatial, and genomic approaches to characterize YFV transmission. We show that the age and sex distribution of human cases is characteristic of sylvatic transmission. Analysis of YFV cases combined with genomes generated locally reveals an early phase of sylvatic YFV transmission and spatial expansion toward previously YFV-free areas, followed by a rise in viral spillover to humans in late 2016. Our results establish a framework for monitoring YFV transmission in real time that will contribute to a global strategy to eliminate future YFV epidemics.
Sepsis: evolving concepts and challenges Salomão, R; Ferreira, B L; Salomão, M C ...
Brazilian journal of medical and biological research,
01/2019, Letnik:
52, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Sepsis remains a major cause of morbidity and mortality worldwide, with increased burden in low- and middle-resource settings. The role of the inflammatory response in the pathogenesis of the ...syndrome has supported the modern concept of sepsis. Nevertheless, a definition of sepsis and the criteria for its recognition is a continuous process, which reflects the growing knowledge of its mechanisms and the success and failure of diagnostic and therapeutic interventions. Here we review the evolving concepts of sepsis, from the "systemic inflammatory response syndrome triggered by infection" (Sepsis-1) to "a severe, potentially fatal, organic dysfunction caused by an inadequate or dysregulated host response to infection" (Sepsis-3). We focused in the pathophysiology behind the concept and the criteria for recognition and diagnosis of sepsis. A major challenge in evaluating the host response in sepsis is to characterize what is protective and what is harmful, and we discuss that, at least in part, the apparent dysregulated host response may be an effort to adapt to a hostile environment. The new criteria for recognition and diagnosis of sepsis were derived from robust databases, restricted, however, to developed countries. Since then, the criteria have been supported in different clinical settings and in different economic and epidemiological contexts, but still raise discussion regarding their use for the identification versus the prognostication of the septic patient. Clinicians should not be restricted to definition criteria when evaluating patients with infection and should wisely use the broad array of information obtained by rigorous clinical observation.
Biomass burning in the Brazilian Amazon is modulated by climate factors, such as droughts, and by human factors, such as deforestation, and land management activities. The increase in forest fires ...during drought years has led to the hypothesis that fire activity decoupled from deforestation during the twenty-first century. However, assessment of the hypothesis relied on an incorrect active fire dataset, which led to an underestimation of the decreasing trend in fire activity and to an inflated rank for year 2015 in terms of active fire counts. The recent correction of that database warrants a reassessment of the relationships between deforestation and fire. Contrasting with earlier findings, we show that the exacerbating effect of drought on fire season severity did not increase from 2003 to 2015 and that the record-breaking dry conditions of 2015 had the least impact on fire season of all twenty-first century severe droughts. Overall, our results for the same period used in the study that originated the fire-deforestation decoupling hypothesis (2003-2015) show that decoupling was clearly weaker than initially proposed. Extension of the study period up to 2019, and novel analysis of trends in fire types and fire intensity strengthened this conclusion. Therefore, the role of deforestation as a driver of fire activity in the region should not be underestimated and must be taken into account when implementing measures to protect the Amazon forest.
In this paper, we investigate a correlation between theoretical calculations and experimental data to explain the electronic structure and optical properties of silver molybdate (β-Ag2MoO4) ...microcrystals synthesized by the microwave-assisted hydrothermal method. X-ray diffraction, Rietveld refinement, and micro-Raman spectroscopy confirmed that these microcrystals crystallize in a spinel-type cubic structure. Field-emission scanning electron microscopy images revealed that the processing temperatures influence in the final shape of microcrystals. Optical properties were analyzed by ultraviolet–visible diffuse reflectance spectroscopy; the increase in the optical band gap energy (E gap) (from 3.24 to 3.31 eV) with processing temperature is associated with the reduction of intermediary energy levels. First-principles quantum mechanical calculations based on the density functional theory at the B3LYP level were conducted. The calculated band structure revealed an indirect E gap of approximately 4.00 and 3.34 eV for the β-Ag2MoO4 without and with the formation of defects, respectively. Theoretical calculations based on density of states and electron density maps were employed to understand the polarization phenomenon induced by structural defects in the β-Ag2MoO4 crystals. Finally, photoluminescence properties at room temperature of β-Ag2MoO4 microcrystals were explained by the charge-transfer mechanism involving tetrahedral MoO4 clusters.
3D printing technologies have been considered an important technology due to the ease manufacturing of objects, freedom of design, waste minimization, and fast prototyping. In chemistry, this ...technology potentializes the fabrication of conductive electrodes in large scale for sensing applications. Herein, we reported the modification of a 3D printed graphene electrode with Prussian blue. The modified electrode (3DGrE/PB) was characterized by microscopy (SEM and AFM) and spectroscopic techniques, and its electrochemical properties were compared to the traditional electrodes: glassy carbon, gold, and platinum. The 3DGrE/PB was used in the sensing of hydrogen peroxide in real-world samples of milk and mouthwash, and the results obtained according to the technique of batch-injection analysis were satisfactory for the concentration range typically found in such samples. Thus, 3DGrE/PB can be used as a new platform for sensing of molecular targets.
The importance of choline chloride (ChCl) is recognized due to its widespread use in the formulation of deep eutectic solvents. The controlled addition of water in deep eutectic solvents has been ...proposed to overcome some of the major drawbacks of these solvents, namely their high hygroscopicities and viscosities. Recently, aqueous solutions of ChCl at specific mole ratios have been presented as a novel, low viscous deep eutectic solvent. Nevertheless, these proposals are suggested without any information about the solid-liquid phase diagram of this system or the deviations from the thermodynamic ideality of its precursors. This work contributes significantly to this matter as the phase behavior of pure ChCl and (ChCl + H
2
O) binary mixtures was investigated by calorimetric and analytical techniques. The thermal behavior and stability of ChCl were studied by polarized light optical microscopy and differential scanning calorimetry, confirming the existence of a solid-solid transition at 352.2 ± 0.6 K. Additionally, heat capacity measurements of pure ChCl (covering both ChCl solid phases) and aqueous solutions of ChCl (
x
ChCl
< 0.4) were performed using a heat-flow differential scanning microcalorimeter or a high-precision heat capacity drop calorimeter, allowing the estimation of a heat capacity change of (ChCl) 39.3 ± 10 J K
−1
mol
−1
, between the hypothetical liquid and the observed crystalline phase at 298.15 K. The solid-liquid phase diagram of the ChCl + water mixture was investigated in the whole concentration range by differential scanning calorimetry and the analytical shake-flask method. The phase diagram obtained for the mixture shows an eutectic temperature of 204 K, at a mole fraction of choline chloride close to
x
ChCl
= 0.2, and a shift of the solid-solid transition of ChCl-water mixtures of 10 K below the value observed for pure choline chloride, suggesting the appearance of a new crystalline structure of ChCl in the presence of water, as confirmed by X-ray diffraction. The liquid phase presents significant negative deviations to ideality for water while COSMO-RS predicts a near ideal behaviour for ChCl.
A comprehensive evaluation of the thermal behavior and heat capacities of ChCl and ChCl + H
2
O and the SLE of ChCl + H
2
O is performed. A new structural model that includes small amounts of water in the ChCl crystal structure is proposed.
In this communication, lipase A from
(CALA) was immobilized by covalent bonding on magnetic nanoparticles coated with chitosan and activated with glutaraldehyde, labelled CALA-MNP, (immobilization ...parameters: 84.1% ± 1.0 for immobilization yield and 208.0 ± 3.0 U/g ± 1.1 for derivative activity). CALA-MNP biocatalyst was characterized by X-ray Powder Diffraction (XRPD), Fourier Transform Infrared (FTIR) spectroscopy, Thermogravimetry (TG) and Scanning Electron Microscope (SEM), proving the incorporation of magnetite and the immobilization of CALA in the chitosan matrix. Besides, the immobilized biocatalyst showed a half-life 8-11 times higher than that of the soluble enzyme at pH 5-9. CALA showed the highest activity at pH 7, while CALA-MNP presented the highest activity at pH 10. The immobilized enzyme was more active than the free enzyme at all studied pH values, except pH 7.
Since December 2016, Brazil has experienced an unusually large outbreak of yellow fever (YF). Whether urban transmission may contribute to the extent of the outbreak is unclear. The objective of this ...study was to characterize YF virus (YFV) genomes and to identify spatial patterns to determine the distribution and origin of YF cases in Minas Gerais, Espírito Santo and Rio de Janeiro, the most affected Brazilian states during the current YFV outbreak.
We characterized near-complete YFV genomes from 14 human cases and two nonhuman primates (NHP), sampled from February to April 2017, retrieved epidemiologic data of cases and used a geographic information system to investigate the geospatial spread of YFV.
All YFV strains were closely related. On the basis of signature mutations, we identified two cocirculating YFV clusters. One was restricted to the hinterland of Espírito Santo state, and another formed a coastal cluster encompassing several hundred kilometers. Both clusters comprised strains from humans living in rural areas and NHP. Another NHP lineage clustered in a basal relationship. No signs of adaptation of YFV strains to human hosts were detected.
Our data suggest sylvatic transmission during the current outbreak. Additionally, cocirculation of two distinct YFV clades occurring in humans and NHP suggests the existence of multiple sylvatic transmission cycles. Increased detection of YFV might be facilitated by raised awareness for arbovirus-mediated disease after Zika and chikungunya virus outbreaks. Further surveillance is required, as reemergence of YFV from NHPs might continue and facilitate the appearance of urban transmission cycles.
Quantiles via moments Machado, José A.F.; Santos Silva, J.M.C.
Journal of econometrics,
11/2019, Letnik:
213, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We study the conditions under which it is possible to estimate regression quantiles by estimating conditional means. The advantage of this approach is that it allows the use of methods that are only ...valid in the estimation of conditional means, while still providing information on how the regressors affect the entire conditional distribution. The methods we propose are not meant to replace the well-established quantile regression estimator, but provide an additional tool that can allow the estimation of regression quantiles in settings where otherwise that would be difficult or even impossible. We consider two settings in which our approach can be particularly useful: panel data models with individual effects and models with endogenous explanatory variables. Besides presenting the estimator and establishing the regularity conditions needed for valid inference, we perform a small simulation experiment, present two simple illustrative applications, and discuss possible extensions.
Peanut (Arachis hypogaea L.) is an important legume cultivated mostly in drought-prone areas where its productivity can be limited by water scarcity. The development of more drought-tolerant ...varieties is, therefore, a priority for peanut breeding programs worldwide. In contrast to cultivated peanut, wild relatives have a broader genetic diversity and constitute a rich source of resistance/tolerance alleles to biotic and abiotic stresses. The present study takes advantage of this diversity to identify drought-responsive genes by analyzing the expression profile of two wild species, Arachis duranensis and Arachis magna (AA and BB genomes, respectively), in response to progressive water deficit in soil. Data analysis from leaves and roots of A. duranensis (454 sequencing) and A. magna (suppression subtractive hybridization (SSH)) stressed and control complementary DNA (cDNA) libraries revealed several differentially expressed genes in silico, and 44 of them were selected for further validation by quantitative RT-PCR (qRT-PCR). This allowed the identification of drought-responsive candidate genes, such as Expansin, Nitrilase, NAC, and bZIP transcription factors, displaying significant levels of differential expression during stress imposition in both species. This is the first report on identification of differentially expressed genes under drought stress and recovery in wild Arachis species. The generated transcriptome data, besides being a valuable resource for gene discovery, will allow the characterization of new alleles and development of molecular markers associated with drought responses in peanut. These together constitute important tools for the peanut breeding program and also contribute to a better comprehension of gene modulation in response to water deficit and rehydration.
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