SARS-CoV-2 transmission occurs mainly indoors, through virus-laden airborne particles. Although the presence and infectivity of SARS-CoV-2 in aerosol are now acknowledged, the underlying ...circumstances for its occurrence are still under investigation. The contamination of domiciliary environments during the isolation of SARS-CoV-2-infected patients in their respective rooms in individual houses and in a nursing home was investigated by collecting surface and air samples in these environments. Surface contamination was detected in different contexts, both on high and low-touch surfaces. To determine the presence of virus particles in the air, two sampling methodologies were used: air and deposition sampling. Positive deposition samples were found in sampling locations above the patient's height, and SARS-CoV-2 RNA was detected in impactation air samples within a size fraction below 2.5 μm. Surface samples rendered the highest positivity rate and persistence for a longer period. The presence of aerosolized SARS-CoV-2 RNA occurred mainly in deposition samples and closer to symptom onset. To evaluate the infectivity of selected positive samples, SARS-CoV-2 viability assays were performed, but our study was not able to validate the virus viability. The presented results confirm the presence of aerosolized SARS-CoV-2 RNA in indoor compartments occupied by COVID-19 patients with mild symptoms, in the absence of aerosol-generating clinical procedures.
Objective
To compare the thermographic pattern of regions of interest (ROI) of respiratory muscles in young asthmatics with and without bronchospasm induced by eucapnic voluntary hyperpnea (EVH).
...Materials and Methods
Cross‐sectional study carried out with 55 young (55% male and 45% females) aged 12.5 ± 3.3 years, divided in nine nonasthmatics, 22 asthmatics without exercise‐induced bronchospasm compatible response (EIB‐cr) and 24 asthmatics with EIB‐cr. The diagnosis of EIB was given to subjects with a fall in forced expiratory volume in the first second (FEV1) ≥ 10% compared to baseline. Thermographic recordings of respiratory muscles were delimited in ROI of the sternocleidomastoid (SCM), pectoral, and rectus abdominis intention area. Thermal captures and FEV1 were taken before and 5, 10, 15 and 30 min after EVH.
Results
Twenty‐four (52.1%) of asthmatics had EIB‐cr. There was a decrease in temperature at 10 min after EVH test in the SCM, pectoral and rectus abdominis ROIs in all groups (both with p < 0.05). There was a decrease in temperature (% basal) in asthmatic with EIB‐cr compared to nonasthmatics in the rectus abdominis area (p < 0.05).
Conclusion
There was a decrease in temperature in the ROIs of different muscle groups, especially in asthmatics. The greater drop in FEV1 observed in individuals with EIB‐cr was initially associated with a decrease in skin temperature, with a difference between the nonasthmatics in the abdominal muscle area. It is likely that this decrease in temperature occurred due to a temporary displacement of blood flow to the most used muscle groups, with a decrease in the region of the skin evaluated in the thermography.
In the search for active, stable, and selective electrocatalysts for glycerol electro-oxidation, this study focuses on the favorable effect that the addition of auxiliary metals, Bi for Pt and Pd, ...and Ag for Au, exerts on these three aspects. Electrocatalysts (Pt/C, Pt3Bi/C, PtBi/C, Au/C, Au3Ag/C, Pd/C and Pd3Bi/C) were successfully prepared by chemical reduction with NaBH4, resulting in nanoparticulate materials. Furthermore, in the case of the Pd3Bi/C, a high degree of Pd–Bi alloy was achieved. When applied to glycerol electrochemical reforming, the electrochemical performance was enhanced so reducing the energy requirements for hydrogen production. Furthermore, in 24 h potentiostatic electrolysis, a smaller decay of the current was observed compared to the monometallic material, especially in the case of the Au3Ag/C and Pd3Bi/C electrocatalysts. Finally, the presence of the auxiliary metals altered the selectivity of the glycerol electro-oxidation. Bismuth added to Pt and Pd leads to an increase in the selectivity toward C3 carboxylates, especially potassium tartronate in Pt–Bi materials operating at 30 °C. When the temperature is increased, this effect is counterbalanced by the larger amount of energy available, leading to a more heterogeneous product distribution in which oxalate and formate appear in higher percentages. Conversely, Ag leads to a more complex distribution product with large percentages of oxalate and formate.
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•Bi acts as a promoter for the glycerol electro-oxidation activity of Pt and Pd.•Ag also promotes the glycerol electro-oxidation activity of Au.•Both auxiliary metals reduce the energy requirements in glycerol electroreforming.•Long-terms stability in glycerol electrolysis is also enhanced.•Bi notably increases the selectivity of Pt and Pd to the formation of tartronate.
The effect of current density and bath temperature in the electroplating process on resistance to corrosion of Zn-Ni alloys was evaluated in this work. The electrolytic bath consisted of nickel ...sulfate, zinc sulfate, sodium sulfate, boric acid, and sodium citrate at pH 7.0. The current density was varied in the range 20–80 mA/cm2 and the bath temperature in the range 30–60 °C. Increasing, independently, the current density or the bath temperature increased the nickel content in the obtained alloy, which affected the alloy microstructure, with a predominant γ phase and cauliflower-like morphology. The nickel content in the alloys was in the range 20–42%wt. A synergistic effect between the current density and bath temperature was observed from a design of experiments and response surface models. The maximum resistance to corrosion occurred for the alloy containing 42%wt. nickel. This alloy was obtained at upper levels of current density and bath temperature, presenting a corrosion potential of −0.789 V and polarization resistance of 4136 Ω.cm2.
This study aims to manufacture and characterize titanium and nickel alloys with different molybdenum (Ti–Ni–Mo) contents, focusing on the influence of these additions on the microstructure, ...mechanical properties, and corrosion resistance. The relevance of this work stems from the lack of research on this specific alloy and the absence of reports in the literature with molybdenum percentages above 2 at.%. Ti50Ni50−XMox alloys were produced by the plasma arc melting method, with six different compositions (x = 0, 0.5, 1, 2, 3, and 4 at.% Mo), and a comprehensive analysis of microstructure, chemical composition, thermal, mechanical, and electrochemical properties was carried out. The results demonstrated significant alterations in the microstructure of the Ni–Ti alloy with the addition of molybdenum presenting several phases, precipitates (TiNi, Ti2Ni), and oxides (Ti4Ni2O, TiO, and TiO3). The stability of the B2 phase increased with molybdenum content, and the monoclinic martensite (B19′) phase was identified only in the Ni–Ti sample. Introducing molybdenum into the Ni–Ti alloy generated the R-phase and shifted the phase transformation peaks to lower temperatures, as differential scanning calorimetry (DSC) indicated. Microhardness and elastic modulus decreased with increasing Mo content, ranging from 494 HV to 272 HV and 74 GPa to 63 GPa, respectively. Corrosion tests revealed increased corrosion resistance with increasing Mo content, reaching a polarization resistance of 2710 kΩ·cm2 and corrosion current of 11.3 µA. Therefore, this study points to Ti–Ni–Mo alloys as potential candidates to increase the range of Ni–Ti alloy applications, mainly in biomaterials, reinforcing its relevance and need in current alloy research.
This study aims to evaluate the effects of melatonin and its mechanisms of action on preantral follicle activation and survival, stromal cell density and collagen distribution in extracellular matrix ...(ECM). The involvement of melatonin receptors and mTORC1 pathway in these procedures were also investigated. To this end, ovarian fragments were cultured for six days in α-MEM+ alone or supplemented with 1000 pM melatonin, 1000 pM melatonin with 1000 pM luzindole (inhibitor of melatonin receptors), or 1000 pM melatonin with 0.16 µg/ml rapamycin (mTORC1 inhibitor). At the end of culture period, tissues were processed for classical histology, and the follicles were classified as normal or degenerated, as well as in primordial or growing follicles. The ovarian stromal cell density and ECM collagen distribution were also evaluated. Samples of ovarian tissues were also destined to measure the levels of thiol and mRNA for CAT, SOD, GPX1 and PRDX1, as well as the activity of antioxidant enzymes CAT, SOD, and GPX1. The results demonstrated that ovarian tissues cultured with melatonin, melatonin with luzindole or melatonin with rapamycin had significantly higher percentage of morphologically normal follicles than those cultured in control medium (α-MEM+). However, the presence of either luzindole or rapamycin, did not block the positive effects of melatonin on follicle survival (P > 0.05). Although the presence of melatonin in culture medium reduced the percentage of primordial follicles and increased the percentage of development follicles, these positive effects of melatonin were blocked by either luzindole or rapamycin (P < 0.05). Melatonin, melatonin with luzindole or melatonin with rapamycin did not influence the number of ovarian stromal cells. In contrast, melatonin significantly increased the percentages of collagen in ovarian tissues, but the positive effects of melatonin were blocked by either luzindole or rapamycin. Tissues cultured with melatonin and rapamycin had higher levels of mRNA for CAT and lower GPx activity when compared to those cultured in control medium. In conclusion, melatonin promotes primordial follicle activation, increases collagen fiber in ECM of in vitro cultured bovine ovarian tissue through its membrane-coupled receptors and mTORC1. Oppositely, melatonin increase follicles survival by acting through other pathways, since it can pass through cell membranes and directly regulate oxidative stress.
The search for catalysts with features that can improve coke resistance and decrease byproduct formation is a current goal in H
production from renewable sources. In this work, the effect of the ...presence of Ni nanoparticles over Co/La-Ce oxides on the ethanol decomposition reaction was studied. Catalysts were synthetized using as precursor a La
Ce
Ni
Co
O
perovskite-type material to ensure a low segregation of phases and a high dispersion of metals. After reduction at 873 K, the perovskite structure was destroyed, and metal Co-Ni particles were supported over a lanthanum-cerium oxide. The materials were characterized by different techniques before and after reaction. Solids exhibited metal particle sizes between 5 and 15 nm demonstrating the advantages of the preparation method to obtain Ni-Co alloys. Although the results of adsorption of ethanol followed by diffuse reflectance infrared fourier transformed spectroscopy (DRIFTS) showed acetate species strongly adsorbed on the catalyst's surface, the material (Ni
Co
/La
Ce
) with the lowest particle size was the most stable system leading to the lowest amount of carbon deposits during ethanol decomposition. This catalyst showed the better performance, with a higher ethanol conversion (98.4%) and hydrogen selectivity (75%). All catalysts exhibited carbonaceous deposits, which were an ordered and disordered carbon phase mixture.
This study aims to enhance energy efficiency by reducing parasitic losses in the engine cooling system through a new drive strategy involving a two-stage water pump and a variable electro-fan. The ...fuel consumption gain analysis focused on a vehicle with average characteristics typical of 1.0L hatchbacks in the Brazilian market and urban driving conditions. The methodology implemented aims to minimize power absorbed by the forced water circulation and thermal rejection, thereby reducing parasitic losses, particularly during low-speed urban driving, without causing air-side heat exchanger saturation. The results show a potential decrease of up to 80% in power absorbed by the cooling system, leading to an estimated fuel consumption saving of approximately 1.4% during urban driving cycles.
To assess the effect of biodentine (BD) and MTA‐angelus (MTA) on biocompatibility, BMP2, BMP4, and osteocalcin (OC) expression. Subcutaneously implanted tubes of four groups (MTA, BD, Control, and ...Sham) were kept over 15, 30, and 60 days; histological analyses were performed using H&E and Von Kossa; ELISA quantified IL‐1β and IL‐8 expression; and qRT‐PCR verified gene expression of BMPs and OC. Sham showed slight changes in profile/intensity of inflammatory infiltrate in all periods. Control had an inflammatory score significantly higher than Sham at 15 days (p < .05). BD revealed a similar inflammatory response to Sham, without significant changes over periods. MTA group exhibited an increase in chronic inflammatory profile at 30 days, with significant reduction at 60 days, when compared to Sham (p < .05). At 30/60 days, experimental groups presented birefringent areas. At 30/60 days, BD and MTA significantly increase IL‐1β compared to Control, whereas an increase in IL‐8 was observed only in BD. At 30/60 days, BD produces an expression of BMP2 whereas MTA influenced BMP4 and OC. Materials tested are biocompatible and they have osteoinductive activity; the materials influenced the expression of the tested mediators differently, suggesting different affinities with the substrate and the dental substrates.
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