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Nonradical Fenton-like catalysis offers opportunities to overcome the low efficiency and secondary pollution limitations of existing advanced oxidation decontamination technologies, but realizing this on transition metal spinel oxide catalysts remains challenging due to insufficient understanding of their catalytic mechanisms. Here, we explore the origins of catalytic selectivity of Fe–Mn spinel oxide and identify electron delocalization of the surface metal active site as the key driver of its nonradical catalysis. Through fine-tuning the crystal geometry to trigger Fe–Mn superexchange interaction at the spinel octahedra, ZnFeMnO₄ with high-degree electron delocalization of the Mn–O unit was created to enable near 100% nonradical activation of peroxymonosulfate (PMS) at unprecedented utilization efficiency. The resulting surface-bound PMS* complex can efficiently oxidize electron-rich pollutants with extraordinary degradation activity, selectivity, and good environmental robustness to favor water decontamination applications. Our work provides a molecule-level understanding of the catalytic selectivity and bimetallic interactions of Fe–Mn spinel oxides, which may guide the design of low-cost spinel oxides for more selective and efficient decontamination applications.

In the last few decades, there has been a trend involving the use of nanoscale fillers in a variety of applications. Significant improvements have been achieved in the areas of their preparation and further applications (e.g., in industry, agriculture, and medicine). One of these promising materials is magnesium oxide (MgO), the unique properties of which make it a suitable candidate for use in a wide range of applications. Generally, MgO is a white, hygroscopic solid mineral, and its lattice consists of Mg2+ ions and O2− ions. Nanostructured MgO can be prepared through different chemical (bottom-up approach) or physical (top-down approach) routes. The required resultant properties (e.g., bandgap, crystallite size, and shape) can be achieved depending on the reaction conditions, basic starting materials, or their concentrations. In addition to its unique material properties, MgO is also potentially of interest due to its nontoxicity and environmental friendliness, which allow it to be widely used in medicine and biotechnological applications.

Heterogeneous peroxymonosulfate (PMS)–based advanced oxidation processes (AOPs) have shown a great potential for pollutant degradation, but their feasibility for largescale water treatment application has not been demonstrated. Herein, we develop a facile coprecipitation method for the scalable production (∼10 kg) of the Cu-Fe-Mn spinel oxide (CuFeMnO). Such a catalyst has rich oxygen vacancies and symmetry-breaking sites, which endorse it with a superior PMS-catalytic capacity. We find that the working reactive species and their contributions are highly dependent on the properties of target organic pollutants. For the organics with electron-donating group (e.g., -OH), high-valent metal species are mainly responsible for the pollutant degradation, whereas for the organics with electron-withdrawing group (e.g., -COOH and -NO₂), hydroxyl radical (•OH) as the secondary oxidant also plays an important role.We demonstrate that the CuFeMnO–PMS system is able to achieve efficient and stable removal of the pollutants in the secondary effluent from a municipal wastewater plant at both bench and pilot scales. Moreover, we explore the application prospect of this PMS-based AOP process for large-scale wastewater treatment. This work describes an opportunity to scalably prepare robust spinel oxide catalysts for water purification and is beneficial to the practical applications of the heterogeneous PMS-AOPs.

Aim To prospectively evaluate the success and survival rates of band and loop (B&L) compared to crown and loop (C&L) space maintainers. Methods Thirty-six children were divided into two groups (18 B&Ls and 18 C&Ls) matched for gender, age and the extracted tooth. For the study group, all clinical procedures were performed by the same paediatric dentist. Regular follow-up appointments were scheduled at 4–6 months. Comparisons in survival time and variables which might have affected the mean survival time were tested using Log rank and Chi-square tests. Results A total of 16 girls and 20 boys (3.4–6.3 years old) were included. The overall failure rate was 53 %. For B&Ls, the failure rate was 83 % compared to 22 % for C&Ls. The main reason for failure of B&Ls was decementation (87 %), while for C&Ls, it was solder breakage (75 %). The mean survival time for B&Ls was 18.8 months, and for C&L, it was 40.4 months ( p  < 0.001). Conclusions The failure rate and mean survival time for C&Ls were clinically and statistically significantly better than those for B&Ls. Depending on the clinical presentation of the abutment tooth and the intended life expectancy of the space maintainer among other factors, it is recommended that, where a space maintainer is indicated in the primary dentition, preference is given to C&L over B&L space maintainers.

The silver, magnesium oxide and gyrotactic microorganism-based hybrid nanofluid flow inside the conical space between disc and cone is addressed in the perspective of thermal energy stabilization. Different cases have been discussed between the spinning of cone and disc in the same or counter wise directions. The hybrid nanofluid has been synthesized in the presence of silver Ag and magnesium oxide MgO nanoparticulate. The viscous dissipation and the magnetic field factors are introduced to the modeled equations. The parametric continuation method (PCM) is utilized to numerically handle the modeled problem. Magnesium oxide is chemically made up of Mg 2+ and O 2- ions that are bound by a strong ionic connection and can be made by pyrolyzing Mg(OH) 2 (magnesium hydroxide) and MgCO 3 (magnesium carbonate) at high temperature (700–1500 °C). For metallurgical, biomedical and electrical implementations, it is more efficient. Similarly, silver nanoparticle's antibacterial properties could be employed to control bacterial growth. It has been observed that a circulating disc with a stationary cone can achieve the optimum cooling of the cone-disk apparatus while the outer edge temperature remains fixed. The thermal energy profile remarkably upgraded with the magnetic effect, the addition of nanoparticulate in base fluid and Eckert number.

Recently, the use of herbs in the agriculture and food industry has increased significantly. In particular, Rosmarinus officinalis L. extracts have been reported to have strong antibacterial properties, which depend on their chemical composition. The present study displayed a biological method for synthesis of magnesium oxide (MgO) nano-flowers. The nano-flowers are developed without using any catalyst agent. Aqueous Rosemary extract was used to synthesize MgO nano-flowers (MgONFs) in stirring conditions and temperature at 70°C for 4 h. The mixture solution was checked by UV-Vis spectrum to confirm the presence of nanoparticles. The MgO nano-flowers powder was further characterized in this study by the X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. In addition, bacteriological tests indicated that MgO nano-flowers significantly inhibited bacterial growth, biofilm formation, and motility of Xanthomonas oryzae pv. oryzae, which is the causal agent of bacterial blight disease in rice. The electronic microscopic observation showed that bacterial cell death may be mainly due to destroy of cell integrity, resulting in leakage of intracellular content. As recommended, the use of Rosemary extract is an effective and green way to produce the MgO nano-flowers, which can be widely used in agricultural fields to suppress bacterial infection.

Spinels can serve as alternative low-cost bifunctional electrocatalysts for oxygen reduction/evolution reactions (ORR/OER), which are the key barriers in various electrochemical devices such as metal–air batteries, fuel cells and electrolysers. However, conventional ceramic synthesis of crystalline spinels requires an elevated temperature, complicated procedures and prolonged heating time, and the resulting product exhibits limited electrocatalytic performance. It has been challenging to develop energy-saving, facile and rapid synthetic methodologies for highly active spinels. In this Article, we report the synthesis of nanocrystalline M x Mn 3– x O 4 (M = divalent metals) spinels under ambient conditions and their electrocatalytic application. We show rapid and selective formation of tetragonal or cubic M x Mn 3– x O 4 from the reduction of amorphous MnO 2 in aqueous M 2+ solution. The prepared Co x Mn 3– x O 4 nanoparticles manifest considerable catalytic activity towards the ORR/OER as a result of their high surface areas and abundant defects. The newly discovered phase-dependent electrocatalytic ORR/OER characteristics of Co–Mn–O spinels are also interpreted by experiment and first-principle theoretical studies. Ceramic preparation of spinels — materials useful for a wide range of applications — requires complicated procedures and heat treatment over long periods. Now, it is shown that rapid synthesis of nanocrystalline Co–Mn–O spinels can be achieved under ambient conditions, and the resulting nanoparticles exhibit considerable catalytic activity towards the electrochemical oxygen reduction/evolution reactions.

Magnesium oxide nanoparticles, or MgO NPs, have garnered a lot of attention because of their exceptional stability, biocompatibility, and antibacterial properties. However, many of the green production methods used today have limited mechanistic knowledge and low reproducibility. In order to get over these challenges, we created a standardized and environmentally friendly process for producing MgO NPs using orange peel extract, a naturally occurring biowaste source rich in phytochemicals that acts as a stabilizing and reducing agent. Active precursor alteration during synthesis was clearly shown by X-ray diffraction (XRD) and thermal analysis (TGA-FTIR), while imaging techniques showed extremely crystalline cubic-phase MgO nanoparticles that were about 9 nm in size. The NPs displayed an irregular shape between 10 and 40 nm and a positive surface charge of +11.74 mV. Terpenoids, polymethoxyflavones, fatty acids, and sugars all work in collaboration with direct nucleation, regulate particle growth, and stabilize the nanoparticles, according to GC-MS analysis. The MgO NPs showed remarkable cytocompatibility in biology, preserving >80% viability in fibroblast and osteoblast cell lines while causing distinct metabolic regulation in osteoblasts without changing the shape of the cells. Consistent moderate activity against a variety of pathogens was confirmed by antimicrobial and antibiofilm assays, with special effectiveness against Gram-positive bacteria and Pseudomonas aeruginosa biofilms. This study shows that these MgO NPs have good biocompatibility and antimicrobial qualities, indicating the need for more research for possible biomedical applications. It also clarifies the molecular role of phytochemicals in nanoparticle formation and provides a repeatable green synthesis pathway.

The discovery of eco-friendly, rapid, and cost-effective compounds to control diseases caused by microbes and insects are the main challenges. Herein, the magnesium oxide nanoparticles (MgO-NPs) are successfully fabricated by harnessing the metabolites secreted by Penicillium chrysogenum. The fabricated MgO-NPs were characterized using UV-Vis, XRD, TEM, DLS, EDX, FT-IR, and XPS analyses. Data showed the successful formation of crystallographic, spherical, well-dispersed MgO-NPs with sizes of 7–40 nm at a maximum wavelength of 250 nm. The EDX analysis confirms the presence of Mg and O ions as the main components with weight percentages of 13.62% and 7.76%, respectively. The activity of MgO-NPs as an antimicrobial agent was investigated against pathogens Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans, and exhibited zone of inhibitions of 12.0 ± 0.0, 12.7 ± 0.9, 23.3 ± 0.8, 17.7 ± 1.6, and 14.7 ± 0.6 mm respectively, at 200 µg mL−1. The activity is decreased by decreasing the MgO-NPs concentration. The biogenic MgO-NPs exhibit high efficacy against different larvae instar and pupa of Anopheles stephensi, with LC50 values of 12.5–15.5 ppm for I–IV larvae instar and 16.5 ppm for the pupa. Additionally, 5 mg/cm2 of MgO-NPs showed the highest protection percentages against adults of Anopheles stephensi, with values of 100% for 150 min and 67.6% ± 1.4% for 210 min.

Microbial infections represent a major hazard to global public health, resulting in extensive morbidity and mortality across the globe. As a result, in the past 10 years, nanoparticles have drawn a lot of interest in their potential to manage microbial diseases. One of the few studies that has used a green and environmentally acceptable approach of producing magnesium oxide nanoparticles (MgONPs) was employed via using an extract from watermelon peels. UV–visible, FTIR, XRD, and TEM were used to comprehensively characterize the biosynthesized MgONPs. The synthetic MgONPs have a polycrystalline form with a median particle size of 6–17 nm, according on the characterization of the material. According to the antimicrobial results, MgONPs showed notable antimicrobial properties toward B . subtitles, S. aureus, E. coli, P. aeruginosa , and C. albicans , with an inhibition zone measuring 18.2 ± 0.36, 23.7 ± 0.4, 15.4 ± 0.25, 17.6 ± 0.56, and 16.3 ± 0.32 mm respectively. While the minimum inhibitory concentrations (MICs) varied from 50 to 200 µg/mL. MgONPs have successfully demonstrated antibiofilm potential versus MRSA. A molecular docking simulation was carried out to obtain a better understanding of the potential mechanism of MgO-NPs against the S. aureus strain. The results imply that the activity may be attributed to the dihydrofolate reductase (DHFR) with a varying degree, and the predominant interaction observed is the hydrophobic interaction with the residues’ amino acids in the active site of the pocket in S. aureus . Furthermore, the DPPH technique revealed that MgONPs had considerable antioxidant activity, with an IC 50 of 223 µg/mL. Additionally, at a dosage of 62.5 µg/mL, MgONPs exhibit possible antiviral efficacy against HAV and HSV1, with proportions of 84.7 and 49.7%, respectively. Finally, the watermelon peel extract biosynthesized MgONPs exhibit antimicrobial, antibiofilm, antioxidant, and antiviral properties that show promise to be utilized in the biomedical field.