The healthy behaviours and COVID-19 mortality among Iranian women: A case–control study

Background: Women are among the susceptible groups to Coronavirus disease-19 (COVID-19) in Ardabil, north-west of Iran, despite the current global status. The underlying causes of high incidence and fatality rate of women in Ardabil are not fully understood. Hence, this study aimed to investigate the healthy behaviours in women of Ardabil and its relationship with COVID-19 mortality. Methods: We conducted a case–control study to compare the adherence to health protocols and behaviours with respect to COVID-19 between the infected (261 patients) and healthy (515 persons) women. Health protocols and behaviours such as using mask, gloves, disinfectants, history of travelling and contacting, and attending various gatherings and places during the COVID-19 pandemic along with demographic variables were defined as independent variables, and COVID-19 death rate was defined as the dependent variable. Multivariable logistic regression methods were used to explore the risk factors associated with COVID-19 mortality. Results: Chi-square and Fisher tests showed significant differences between infected and healthy women in terms of history of contact and traveling (p < 0.05), wearing mask (p < 0.001), going to work place (p < 0.001), and attend public gatherings (p = 0.038). Multivariable logistic regression disclosed that the age group over 80 years: 8.97 times (95% CI 2.27–29.85), women with underlying chronic diseases: 4.14 times (95% CI 1.61–10.64), and obese women: 3.01 times (95% CI 1.04–6.03) were more likely to die from COVID-19 than other women. Conclusion: Considering the high incidence and mortality rate in Ardabil women due to COVID-19 and the corresponding health behavioural factors, special emphasis should be given to the increase of women awareness on the importance of healthy behaviours, diet, and life-style

Development and evaluation of niobium and molybdenum substituted magnetite catalysts for fenton-like treatment of recalcitrant wastewaters / Shima Rahim Pouran

Iron oxides are conventionally used as heterogeneous Fenton catalysts because of their abundance, ease of separation, affordability, and applicability in broad pH range. This is especially reported for magnetite due to the presence of Fe2+ cations in its structure. However, the magnetite-catalyzed Fenton reaction has lower reaction rate compared with the homogeneous reaction, which led to the introduction of transition metal-substituted magnetites. Previous studies focused mainly on the fourth series transition metals of the periodic table, and there have not been any comprehensive study on the effects of the transition metals from period five on the structure and activity of magnetite in Fenton process. Therefore, the present study synthesized a series of single, and co-doped niobium and/or molybdenum substituted magnetites by co-precipitation method prior to characterization. The amount of Nb and Mo incorporated in the samples were: Fe3-xNbxO4 (x = 0.022, 0.049, 0.099, and 0.19), Fe3-xMoxO4 (x = 0.028, 0.069, 0.13, and 0.21) and Fe3-x-yNbxMoyO4 (x = 0.025, 0.049, 0.099, 0.149, and 0.171; y = 0.094, 0.089, 0.073, 0.032, and 0.023). All samples maintained the inverse spinel structure and magnetic property. The imported Nb4+ and Mo4+ mainly replaced the octahedral Fe3+ and Fe2+ cations, respectively. Higher Nb and Mo content decreased the crystal size significantly with concomittant increase in specific surface area, resulting in higher adsorption capacity of the catalysts. Subsequently, the activity of the synthesized samples was tested through the Fenton-like reaction for degradation of a model wastewater (methylene blue solution, MB). The presence of transition metals significantly improved the degradation of MB, especially with higher Nb and Mo contents in which, complete MB removal was achieved within 180 min. This could be attributed to a combination of factors: (i) increased adsorption capacity of the samples evidenced by larger surface area; (ii) participation of thermodynamically favorable Nb4+/Nb5+ and Mo4+/Mo6+ redox pairs iv in regeneration of Fe2+ and •OH radical generation, (iii) presence of oxygen vacancies serves as active sites on the surface of the catalysts, and (iv) direct involvement of peroxo-niobium complexes in MB degradation. Three catalysts, Fe2.79Nb0.19O4, Fe2.79Mo0.13O4 and Fe2.79Nb0.171Mo0.023O4, with the highest activity in the Fenton reaction were chosen, and used for treatment of MB and methyl orange (MO) solutions through the Fenton-like, UV/Fenton-like and US/Fenton-like reactions. The incorporated Nb and Mo significantly accelerated MB degradation in the US/Fenton followed by the UV-B/Fenton and UV-A/Fenton reactions. However, UV-B/Fenton reaction was more effective in degrading MO compared to the other oxidation systems. Furthermore, MB adsorption on the surface of the samples was well described by pseudo-second-order model kinetics. In addition, MB oxidation through the Fenton reaction catalyzed by the Fe3-xNbxO4, Fe3-xMoxO4, and Fe3-x-yNbxMoyO4 samples was well described by the pseudo-first-order, zero-order, and pseudo-first-order kinetics, respectively. The amount of leached iron and incorporated transition metals were not significant in acidic condition and undetectable in neutral and basic solutions. The samples retained their catalytic efficiency after three recycles in Fenton process. The results proved that niobium and molybdenum substituted magnetites enhanced the Fenton oxidation of organic pollutants. Therefore this highlights the promising potentials for treating recalcitrant effluent

G-C3N4 Dots Decorated with Hetaerolite: Visible-Light Photocatalyst for Degradation of Organic Contaminants

In this paper, a facile hydrothermal approach was used to integrate graphitic carbon nitride dots (CNDs) with hetaerolite (ZnMn2O4) at different weight percentages. The morphology, microstructure, texture, electronic, phase composition, and electrochemical properties were identified by field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), ultraviolet-visible diffuse reflectance (UV-vis DR), photoluminescence (PL), electrochemical impedance spectroscopy (EIS), Brunauer&ndash;Emmett&ndash;Teller (BET), Barrett&ndash;Joyner&ndash;Halenda (BJH), and photocurrent density. The results of XRD, FT-IR, EDX, and XPS analyses confirmed the synthesis of CNDs/ZnMn2O4 (20%) nanocomposite. As per PL, EIS, and photocurrent outcomes, the binary CNDs/ZnMn2O4 nanocomposite revealed superior features for interfacial transferring of charge carriers. The developed p&ndash;n heterojunction at the interface of CNDs and ZnMn2O4 nanoparticles partaken a significant role in the impressive charge segregation and migration. The binary nanocomposites were employed for the photodegradation of several dye pollutants, including rhodamine B (RhB), fuchsin, malachite green (MG), and methylene blue (MB) at visible wavelengths. Amongst the fabricated photocatalysts, the CNDs/ZnMn2O4 (20%) nanocomposite gave rise to about 98% RhB degradation efficiency within 45 min with the rate constant of 747 &times; 10&minus;4 min&minus;1, which was 66.5-, 3.44-, and 2.72-fold superior to the activities of CN, CNDs, and ZnMn2O4 photocatalysts, respectively. The impressive photodegradation performance of this nanocomposite was not only associated with the capacity for impressive visible-light absorption and boosted separation and transport of charge carriers, but also with its large surface area

G-C₃N₄ Dots Decorated with Hetaerolite: Visible-Light Photocatalyst for Degradation of Organic Contaminants

In this paper, a facile hydrothermal approach was used to integrate graphitic carbon nitride dots (CNDs) with hetaerolite (ZnMn2O4) at different weight percentages. The morphology, microstructure, texture, electronic, phase composition, and electrochemical properties were identified by field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), ultraviolet-visible diffuse reflectance (UV-vis DR), photoluminescence (PL), electrochemical impedance spectroscopy (EIS), Brunauer–Emmett–Teller (BET), Barrett–Joyner–Halenda (BJH), and photocurrent density. The results of XRD, FT-IR, EDX, and XPS analyses confirmed the synthesis of CNDs/ZnMn2O4 (20%) nanocomposite. As per PL, EIS, and photocurrent outcomes, the binary CNDs/ZnMn2O4 nanocomposite revealed superior features for interfacial transferring of charge carriers. The developed p–n heterojunction at the interface of CNDs and ZnMn2O4 nanoparticles partaken a significant role in the impressive charge segregation and migration. The binary nanocomposites were employed for the photodegradation of several dye pollutants, including rhodamine B (RhB), fuchsin, malachite green (MG), and methylene blue (MB) at visible wavelengths. Amongst the fabricated photocatalysts, the CNDs/ZnMn2O4 (20%) nanocomposite gave rise to about 98% RhB degradation efficiency within 45 min with the rate constant of 747 × 10−4 min−1, which was 66.5-, 3.44-, and 2.72-fold superior to the activities of CN, CNDs, and ZnMn2O4 photocatalysts, respectively. The impressive photodegradation performance of this nanocomposite was not only associated with the capacity for impressive visible-light absorption and boosted separation and transport of charge carriers, but also with its large surface area

A comprehensive study on antidiabetic and antibacterial activities of ZnO nanoparticles biosynthesized using Silybum marianum L seed extract

Green synthesis of ZnO nanoparticles (NPs) using the plants’ extract and their potential application have driven a tremendous interest in recent years. This study reports a green microwave-assisted method for synthesis of ZnO NPs using Silybum marianum L. seed extract. Characteristics of the as-prepared sample was explored in terms of crystalline phase, morphology, composition, surface area, optical, and thermal properties. The particles of the biosynthesized sample (ZnO/extract) had smaller sizes than the chemically produced one (ZnO). The existence of biomolecules from Silybum marianum L seed extract linked to the ZnO/extract sample was approved by various analyses. The ZnO/extract sample was used for treating alloxan-induced diabetic rats and its efficiency was compared with ZnO, extract, and insulin treatments. For this purpose, the levels of blood glucose, insulin, total cholesterol, total triglyceride, and high-density lipoprotein were measured before and after treating with the studied treatment agents and compared with each other. Moreover, the antibacterial activities of both ZnO samples were investigated against E. coli to assess their potential antibacterial application. From the results, ZnO/extract NPs represented an outstanding performance in overcoming the diabetic disorders and good antibacterial activity against the studied bacteria

A Comparative Study on a Cationic Dye Removal through Homogeneous and Heterogeneous Fenton Oxidation Systems

Oxidative treatment of a cationic dye solution, methylene blue, was investigated using magnetite nanoparticles and goethite in heterogeneous Fenton-like reaction, and ferrous ions in homogeneous Fenton-reaction. The aim was to compare the degradation efficiencies of the studied catalysts for decolorization of methylene blue solution as the model organic pollutant. Response surface methodology (RSM) was applied to determine the optimal operational conditions for magnetite/H2O2 and goethite/H2O2 systems. The [H2O2] of 0.2 M, catalyst dosage of 1 g/L, pH 9.0 and reaction time of 5h were chosen by RSM. The pH value of 3.0 was used in the case of Fe+2/H2O2 system. The experimental results showed that homogeneous Fenton oxidation system was the most effective system under both acidic and neutral conditions but decreased at pH value of 9.0 due to the decrease in available Fe2+ ions in the solution and generation of ferric hydroxide sludge. Fe3O4/H2O2 system represented better removal efficiency than FeO(OH)/H2O2 system that could be attributed to the presence of FeII cations in magnetite structure and its larger surface area

Comprehensive study on the influence of molybdenum substitution on characteristics and catalytic performance of magnetite nanoparticles

We prepared a number of heterogeneous catalysts by exchanging the structural iron of magnetite with molybdenum ions. To obtain the optimum value, Mo at various concentrations was coprecipitated with iron species (Fe3−x Mo x O4, x = 0.028, 0.069, 0.13, and 0.21). Characterization revealed that all the samples had inverse spinel structure with excellent stability and magnetic properties. Higher Mo contents (x = 0.13 and 0.21) significantly improved the specific surface area of magnetite, leading to higher capacity for methylene blue (MB) adsorption. The catalytic performance of the samples for degradation of MB solution through Fenton reaction was then assessed. The Fe2.62Mo0.21O4 sample showed substantial activity, removing MB completely within 150 min. This enhanced activity is discussed based on the enlarged surface area, the role of surface Mo4+/Mo6+ redox pairs, and oxygen vacancies. Kinetic studies revealed that MB degradation by Fe3−x Mo x O4 nanoparticles in presence of H2O2 was well fit by a zeroth-order kinetics model. These results support use of such Fe3−x Mo x O4 materials as active magnetically separable heterogeneous catalysts, capable of degrading various contaminants through Fenton reaction