Structural, Optical, and Renewable Energy-Assisted Photocatalytic Dye Degradation Studies of ZnO, CuZnO, and CoZnO Nanostructures for Wastewater Treatment

Renewable energy can be harnessed from wastewater, whether from municipalities or industries, but this potential is often ignored. The world generates over 900 km3 of wastewater annually, which is typically treated through energy-consuming processes, despite its potential for energy production. Environmental pollution is a most important and serious issue for all and their adulterations to the aquatic system are very toxic in very low concentrations. Photocatalysis is a prominent approach to eliminating risky elements from the environment. The present study developed Zinc oxide (ZnO), Copper-doped Zinc oxide (CuZnO), and Cobalt-doped Zinc oxide (CoZnO) nanostructures (NSs) by facile hydrothermal route. The crystalline and structural stability of the synthesized nanostructures were evident from XRD and FESEM analysis. Metal, and oxygen bond and their interaction on the surfaces and their valency were explored from XPS spectra. Optical orientations and electron movements were revealed from UV-Visible analysis. After 100 min exposure time with 1 g of catalyst concentration 60%, 70%, and 89% of dye degraded, for dye concentration (5 mg/L to 50 mg/L), the huge variation observed (70% to 22%), (80% to 16%), (94% to 10%). The highest photodegradation rate (55%, 75%, 90%) was observed on pH~12 using ZnO, CoZnO, and CuZnO respectively. Photodegradation of methylene blue confirmed the largest surface area, rate of recombination, photo-excited charge carriers, photo-sensitivity range, and radical generations of ZnO, CuZnO, and CoZnO. The present study, therefore, suggested that CuZnO would be preferred to produce nanomaterials for industrial wastewater treatment like methylene

Mechanisms of Resistance to the Novel Antibiotic Combination Ceftazidme/Avibactam and to Avibavtam Alone in Salmonella Enterica Serovar Senftenberg

The use of β-lactam/β-lactamase inhibitors combinations has been the most significant revolution to overcome β-lactamases resistance. In 2015, the Food and Drug Administration approved the use of ceftazidime/avibactam for infections caused by Enterobacteriaceae and Pseudomonas aeruginosa. Only limited data are currently available for resistance to this combination. The study, for the first time, aims to examine mechanisms of resistance to avibactam and to ceftazidime/avibactam in Salmonella senftenberg. Bacteria were challenged with gradually increasing concentrations of either avibactam or ceftazidime/avibactam, and developed resistance to the drugs at 10-fold of the initial MIC after 43 serial transfers. Whole genome and RNA sequencing was applied to determine whether new genetic variations are associated with the resistance. No mutations or hyperproduction of β-lactamases were found. Acquisition of ceftazidime/avibactam resistance was associated with mutations in PBP 2 and 3, porin, and major facilitator superfamily (MFS) transporter, whereas acquisition of avibactam resistance was associated with mutations in PBP2, S6 unit of 30S rRNA, MFS and ATP binding cassette (ABC) transporters. Altogether, this study raises the concern regarding the ability of ceftazidime-susceptible bacteria to develop resistance to this novel combination, a resistance that is also correlated with cross-resistance to other antibiotics

The Effect of Sewak on Oral Microbiota Composition

Considerable data by many experimental studies have provided that the S. persica plant and its chewing sticks (sewak) display beneficial effects for oral hygiene. To find out more about the shadowy benefits of sewak, we hypothesized that sewak can be a natural therapeutic approach that controls the microbiota composition. Surveys and mouthwash samples with and without the use of sewak were obtained from six healthy randomly selected volunteers. Samples were processed and DNA isolated using QlAamp kit. 16S metagenomics sequencing library approach (Illumina) for sequencing the variable V3 and V4 domains of the 16S rRNA gene was used since purposes such as genus and species were needed in this study. Each samples were sequenced to a depth of 380,000 reads in the paired-end 2x300 read format. Taxonomic identification and statistical analysis revealed that after using the sewak treatment, some species decreased and other increased (P \u3c 0.05). However, when the p-value was adjusted using FDR, results indicated that no one of the bacteria species can be considered as statistically significant (FDR\u3e0.05). The comprehensive examination of the relationship of sewak and the oral microbiota demonstrates that there is no difference in the entire number of bacteria before and after treatment, based on analysis. It is possible that sewak use may reduce oral bacteria in a global, proportional manner, such that the microbiome approach could not detect such changes, since the method is designed to measure composition changes, not absolute changes

Biologically Reduced Zinc Oxide Nanosheets Using Phyllanthus emblica Plant Extract for Antibacterial and Dye Degradation Studies

The nanostructures synthesized using the green chemistry method have recently attracted the attention of scientists due to their significance in many scientific domains. This work provides an overview of the biosynthesis of zinc oxide (ZnO) nanosheets (NSs) using Phyllanthus emblica plant (PEP) extract. X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) were used to analyze the synthesized ZnO-NSs. Evaluation of the antibacterial activity of biosynthesized ZnO-NSs was performed. ZnO-NSs exhibit effective antibacterial activity against Gram-positive (S. pyogenes and S. aureus) and Gram-negative (S. typhi and E. coli) bacterial strains. S. typhi is the most sensitive microbe towards ZnO-NSs and formed a 21 mm zone of inhibition (ZOI). ZnO-NSs are also tested as a photocatalyst in the degradation of methyl orange (MO) and rhodamine B (RB). The degradation rate of MO was 90%, and RB was 96% after being exposed to UV light for 120 min. The as-synthesized ZnO-NSs exhibited selective dye degradation and showed relatively better photocatalytic activity for positively charged (cationic) dyes. This work could lead to the fabrication of high-yield photocatalysts, which have the potential to degrade textile dyes from aqueous solution