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Glycerol is a biomass-derivative feedstock with potential use in direct alcohol fuel cells. In this work, we have studied the influence of distinct carbon-supports for Pt-Sb catalysts ...applied to glycerol electrooxidation reaction. The carbon matrixes were synthesized from Si templates with distinct geometries, giving the so-called CMK-3 and CMK-5, whose 3D structures were characterized employing SAXS, TGA, TEM, and N2 adsorption isotherms. Pt nanoparticles were synthesized onto the carbon structures (Pt/Cx within X = CMK-3, CMK-5, or Vulcan) and converted to Pt-Sb/C catalysts by irreversible Sb2O3 adsorption on Pt/Cx covering up to 97% of Pt surface as inferred by cyclic voltammograms. Regardless of the carbon support, the onset of glycerol oxidation on Pt-Sb/C is ca 0.4 V (vs RHE), however, at higher potentials in cyclic voltammetric conditions or chroamperometric curves, Pt-Sb/CCMK-3 depicted the best activity among the synthesized catalysts, providing currents 1.6 and 2.0 times bigger than those in Pt-Sb/CCMK-5 and Pt-Sb/CVulcan, respectively after 800 s at 0.5 V. The results are explained utilizing the coupled between the glycerol mass transport from bulk to active sites in carbon matrixes and re-adsorption of partially oxidized reaction products.
The behavior of gas bubbles produced during electrochemical processes is of large interest because of the increase in cell overpotential induced by their production, the electrode surface covering by ...them and, finally, the detachment of these bubbles and their direct impact on the energy consumption during the reaction. In this work, we used coupled experimental and computational approaches to investigate bubble formation under those conditions where there are important convective effects. We have measured both normal and parallel velocity of the solution and built up a computational fluid dynamics (CFD) model. The results were compared to experimental data. Then, having the computational model validated by experimental data, we have simulated different conditions following bubble displacement. An important change of the surface covering is observed during the electrochemical reaction. Considering just the covering change, for example, there is up to 23 % increase comparing to the electrode edge and center.
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•Finite element method is suitable to evaluate the bubble-induced convection.•The bubbles create a vortex in the electrolyte.•The induced convection create a non-homogeneous gas covering over electrode surface.•The bubble size has an important effect in the covering variance.
Bacteria and wild yeasts contamination is usually observed during fuel ethanol fermentation. Moreover, it is known that sucrose (the main carbohydrate in sugarcane juice) is breakdown into glucose ...and fructose by the yeast enzyme invertase, but hydrolysis is much faster than hexoses metabolism, resulting in monosaccharides accumulation which exerts osmotic stress on yeast and growth of Lactobacillus contaminants. Nonetheless, the knowledge about the effect of invertase enzyme on these contaminants is still scarce, especially because the wort composition can differ from exclusive sugarcane juice to a mixture of juice and molasses. Invertase activity and viability of five strains of Saccharomyces cerevisiae (PE-2, BG-1, CAT-1, FLE and IZ-1904) were quantified and correlated with bacterial contamination in fermentations with biomass recycling. Invertase activity was verified to be, in ascending order: CAT-1 <PE-2 <BG-1 <IZ-1904 <FLE. However, PE-2 and BG-1 were the strains that showed higher ethanol yield (%) in all fermentation cycles except for the first one, and although the yeasts FLE and IZ-1904 exhibited the lowest viabilities, they were not followed by an increase in bacterial proliferation. Thus, the results indicated that the yeast invertase activity does not influence the levels of contamination by Lactobacillus fermentum.
•Invertase activity from different strains was studied during ethanolic fermentation with cell recycling.•The invertase influence on the contamination level by Lactobacilli was investigated.•Ethanol yield, yeasts viability, yeasts budding rate and bacterial contamination were reported.•No differences on the levels of contamination were observed during co-culture fermentation processes.
In Brazil, a substantial number of coronavirus disease (COVID-19) cases and deaths have been reported. It has become the second most affected country worldwide, as of June 9, 2020. Official Brazilian ...government sources present contradictory data on the impact of the disease; thus, it is possible that the actual number of infected individuals and deaths in Brazil is far larger than those officially reported. It is very likely that the actual spread of the disease has been underestimated.
This study investigates the underreporting of cases and deaths related to COVID-19 in the most affected cities in Brazil, based on public data available from official Brazilian government internet portals, to identify the actual impact of the pandemic.
We used data from historical deaths due to respiratory problems and other natural causes from two public portals: DATASUS (Department of Informatics of the Unified Healthcare System) (2010-2018) and the Brazilian Transparency Portal of Civil Registry (2019-2020). These data were used to build time-series models (modular regressions) to predict the expected mortality patterns for 2020. The forecasts were used to estimate the possible number of deaths that were incorrectly registered during the pandemic and posted on government internet portals in the most affected cities in the country.
Our model found a significant difference between the real and expected values. The number of deaths due to severe acute respiratory syndrome (SARS) was considerably higher in all cities, with increases between 493% and 5820%. This sudden increase may be associated with errors in reporting. An average underreporting of 40.68% (range 25.9%-62.7%) is estimated for COVID-19-related deaths.
The significant rates of underreporting of deaths analyzed in our study demonstrate that officially released numbers are much lower than actual numbers, making it impossible for the authorities to implement a more effective pandemic response. Based on analyses carried out using different fatality rates, it can be inferred that Brazil's epidemic is worsening, and the actual number of infectees could already be between 1 to 5.4 million.
To determine whether tocilizumab improves clinical outcomes for patients with severe or critical coronavirus disease 2019 (covid-19).
Randomised, open label trial.
Nine hospitals in Brazil, 8 May to ...17 July 2020.
Adults with confirmed covid-19 who were receiving supplemental oxygen or mechanical ventilation and had abnormal levels of at least two serum biomarkers (C reactive protein, D dimer, lactate dehydrogenase, or ferritin). The data monitoring committee recommended stopping the trial early, after 129 patients had been enrolled, because of an increased number of deaths at 15 days in the tocilizumab group.
Tocilizumab (single intravenous infusion of 8 mg/kg) plus standard care (n=65) versus standard care alone (n=64).
The primary outcome, clinical status measured at 15 days using a seven level ordinal scale, was analysed as a composite of death or mechanical ventilation because the assumption of odds proportionality was not met.
A total of 129 patients were enrolled (mean age 57 (SD 14) years; 68% men) and all completed follow-up. All patients in the tocilizumab group and two in the standard care group received tocilizumab. 18 of 65 (28%) patients in the tocilizumab group and 13 of 64 (20%) in the standard care group were receiving mechanical ventilation or died at day 15 (odds ratio 1.54, 95% confidence interval 0.66 to 3.66; P=0.32). Death at 15 days occurred in 11 (17%) patients in the tocilizumab group compared with 2 (3%) in the standard care group (odds ratio 6.42, 95% confidence interval 1.59 to 43.2). Adverse events were reported in 29 of 67 (43%) patients who received tocilizumab and 21 of 62 (34%) who did not receive tocilizumab.
In patients with severe or critical covid-19, tocilizumab plus standard care was not superior to standard care alone in improving clinical outcomes at 15 days, and it might increase mortality.
ClinicalTrials.gov NCT04403685.
Humankind has experienced a remarkable development since it began to design and optimize chemical reactions to achieve valuable compounds. The key to accomplish these tasks is the proper ...understanding of how chemical transformations occur at a molecular level, that is, their reaction mechanisms. Based on a suitable mechanistic proposal, experimentalists choose a given chemical protocol to optimize experimental conditions, design new synthetic routes, and circumvent competing reactions. In this context, computational chemistry has become a valuable ally for mechanistic elucidation. We present herein a review of complementary collaborations between experimentalists and theoretical chemists to rationalize processes at the molecular level, focusing mainly on the fields of organic synthesis, natural product chemistry, and systems with environmental interest. Throughout this review, we highlight the ability of computational evaluations to provide answers to questions raised from experiments in a clear and direct way, indicating to experimentalists alternative paths to help them solve their problems.
Stevia rebaudiana, as a short-day perennial, produces steviol glycoside (StGlys) metabolites recognized as healthy natural sweeteners, ca. 300 times sweeter than sucrose, being stevioside (ST) and ...rebaudioside A (Reb-A), the main StGlys for the natural sweetener demanding industries. Nevertheless, discussions persist regarding the ideal light regimen and respective StGlys biosynthesis regulation in S. rebaudiana aimed at enhancing and optimizing the StGlys large-scale production for industrial purposes. The present work reports on the biosynthesis and the contents of StGlys in leaves and stems in different developmental stages of S. rebaudiana plants submitted to different photoperiods. The final contents resulted from the response of genes in the shared StGlys and gibberellins (GAs) biosynthesis pathway, notably showing differential gene expression patterns in leaves and stems at the different developmental stages. Plants developing under 16/8 h (light/dark) photoperiod increased StGlys contents resulting from the upregulation of S. rebaudiana kaurenoic acid 13-hydroxylase (SrKAH) and uridine diphosphate glycosyltransferase (SrUGTs) genes in association with the downregulation of GAs biosynthesis-related genes in leaves. In contrast, the positive overall regulation of GAs biosynthesis genes in stems appeared as a requirement of GAs for stem elongation and plant growth. Conclusively, the research reports a deeper understanding of transcriptional responses, biosynthesis, and ST and Reb-A yield mechanisms in S. rebaudiana plants under different photoperiodic conditions. Altogether, leading to the potential optimization of commercial production, extraction, and purification while highlighting photoperiodic-responsive StGlys/GAs genes as potential molecular targets for metabolic engineering and future development of superior S. rebaudiana genotypes aiming further large-scale StGlys production and yield to attend the continuous increasing commercial and industrial demand.
•GAs plays a key role in stem vegetative elongation in S. rebaudiana.•Stems constitute a potential target for sweetener production in S. rebaudiana.•Upregulated StGlys genes increased sweetening metabolites in S. rebaudiana.•Appointed potential gene targets for StGlys enhancement in S. rebaudiana.
•This paper reports the synthesis of (±)-licarin A.•Three semi-synthetic derivatives of (±)-licarin A also were prepared.•The compounds were evaluated against Trypanosoma cruzi, and Schistosoma ...mansoni.•Licarin A was the most active against T. cruzi.•The acetylated derivative was the most active against S. mansoni.•Computational study
This paper reports the synthesis of (±)-licarin A 1, a dihydrobenzofuran neolignan, resultant of an oxidative coupling reaction of isoeugenol and horseradish peroxidase (HRP) enzyme. Following, three semi-synthetic derivatives from this compound were obtained: benzylated (±)-licarin A 2, methylated (±)-licarin A 3 and acetylated (±)-licarin A 4. After structural elucidation and assignment by Nuclear Magnetic Resonance of 1H, 13C and DEPT, all compounds were evaluated in vitro against Trypomastigote forms of Trypanosoma cruzi (T. cruzi), the etiologic agent of Chagas disease, and Schistosoma mansoni (S. mansoni) worms, the etiologic agent of schistosomiasis. Compound (4) was the most active against S. mansoni adult worms, displaying worm viability reduction at 25 µM and mortality of all worms at 100 and 200 µM within 24 h. Compound 1 was the second most active, showing worm viability reduction at 50 µM and mortality of 25% and 100% of worms in 24h at concentrations of 100 and 200 µM, respectively. In addition, theoretical calculations aiming at finding molecular properties that showed the correlation for schistosomicidal and trypanocidal activities of (±)-licarin A and three of its semi-synthetic derivatives were also performed.
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The area of social skills is broad, in theory and in practice. For social skills training, various clinical practices have been applied in group sessions, as have motivational resources such as ...role-playing games (RPGs). In recent years, the need arose to assess the clinical impact of the pandemic. The objective of this study was to determine the impact that the pandemic has had on in-person and online social skills training.
We evaluated six subjects with autism spectrum disorder, with or without another, similar disorder, each of whom attended a total of 12 two-hour RPG sessions over a 12-month period. The original (Portuguese-language) version of the Social Skills Inventory for Adolescents was applied at three different time points (pre-, mid-, and post-intervention).
After six in-person tabletop RPG sessions, there was an increase in the mean frequency scores and a decrease in the mean difficulty scores. However, during the pandemic, the remaining six sessions were conducted online and the effect was the opposite.
Our data indicate that there is a need for further studies assessing social skills training in online contexts.
Macrophage migration and adhesion are important for the control of mycobacterial infection and are critically dependent on the reorganization of the cytoskeleton. Mycobacteria elicit rapid ...morphological changes, such as cell spreading, a process relevant to in vivo changes of macrophage shape during extravasation and migration. In this study, we investigated the BCG mycobacteria‐induced signaling events leading to macrophage cytoskeletal rearrangements employing specific pharmacological inhibitors to suppress distinct kinase pathways known to be elicited by infection. Viable or lysed mycobacteria, as well as purified cell wall lipoprotein p19, TLR2 agonist, induced RAW264.7 cells to extend actin‐rich pseudopods, which impart radial spreading within 3 h, leading later to persistent cell polarization. BCG induced rapid activation of phosphatidylinositol 3‐kinase, PI3K, activation that was recruited to the activated TLR2 receptor. TLR2‐ neutralizing antibody inhibited macrophage spreading and PI3K activation induced by p19. Additionally, BCG induced spreading and polarization of bone marrow‐derived macrophages from TLR2‐ expressing mice in contrast to their TLR2‐knockout counterparts. Neither MEK1/ERK, p38 MAPK, nor NF‐κB activation were important for the early cytoskeletal rearrangements observed, although suppression of these pathways is known to inhibit chemokine secretion by activated macrophages. Β2‐integrins blockade with a corresponding antibody inhibited macrophage spreading and polarization but had no effect on pseudopodia protrusions demonstrating the downstream position of integrin‐mediated adhesion in PI3K‐ dependent signaling pathway leading to the motility phenotype. The obtained data demonstrate that the direct effect of mycobacteria on macrophage shape might be mediated through TLR2‐dependent PI3K activation.
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