Effect of Calcination Temperature on Photocatalytic Degradation Performance of Electrospun β-Ga2O3 Nanofibers

In the present work, Ga2O3 nanofibers were successfully synthesized by electrospinning a solution of polyvinylpyrrolidone (PVP) and gallium nitrate, followed by temperature-controlled calcination treatment of the as-spun PVP and gallium nitrate composite nanofibers. The crystallinity and crystallite size of the Ga2O3 nanofibers can be readily controlled by varying the calcination temperature. From the physicochemical analysis results of the synthesized nanofiber, it was found that the nanofiber calcined at a higher temperature showed a higher crystallinity and a larger crystallite size. The photocatalytic degradation results on rhodamine-B (Rho B) revealed that the photocatalytic activity of the Ga2O3 nanofibers can be improved by optimizing the conflicting characteristics, crystallinity and crystallite size, through the control of the calcination temperature. The photocatalytic activity of a nanofiber calcined at 800 °C for the degradation of Rho B under ultraviolet irradiation exhibits 2.39 and 1.16 times higher than that of nanofibers synthesized at 700 °C and 900 °C, respectively, which is ascribed to relatively efficient charge transfer and dye molecule adsorption by its proper crystallinity and crystallite size.

Pyoverdine Inhibitors and Gallium Nitrate Synergistically Affect Pseudomonas aeruginosa

P. aeruginosa is one of the most common causative agents for ventilator-associated pneumonia and nosocomial bacteremia and is a leading cause of death in patients with cystic fibrosis. Pandrug-resistant strains of P. aeruginosa are increasingly identified in clinical samples and show resistance to virtually all major classes of antibiotics, including aminoglycosides, cephalosporins, and carbapenems.

Inhibition of LpxC Increases the Activity of Iron Chelators and Gallium Nitrate in Multidrug-Resistant Acinetobacter baumannii

Infections caused by multidrug-resistant Acinetobacter baumannii would benefit from the development of novel treatment approaches. Compounds that interfere with bacterial iron metabolism, such as iron chelators and gallium nitrate, have previously been shown to have antimicrobial activity against A. baumannii. In this study, we characterize the effect of LpxC inhibitors on the antimicrobial activity of previously characterized iron chelators, 2,2′-bipyridyl (BIP) and deferiprone (DFP), and gallium nitrate (Ga(NO3)3) against A. baumannii reference strains and multidrug-resistant clinical isolates. The LpxC inhibitor LpxC-2 was synergistic with BIP for 30% of strains tested (FICI values: 0.38–1.02), whereas inhibition with LpxC-4 was synergistic with BIP for 60% of strains tested (FICI values: 0.09–0.75). In time–kill assays, combinations of BIP with both LpxC inhibitors demonstrated synergistic activity, with a more than 3 log10 reduction in bacterial counts compared to BIP alone. LpxC-2 was synergistic with Ga(NO3)3 for 50% of strains tested (FICI values: 0.27–1.0), whereas LpxC-4 was synergistic with Ga(NO3)3 for all strains tested (FICI values: 0.08–≤0.50). In time–kill assays, combinations of Ga(NO3)3 with LpxC-2 and LpxC-4 decreased the growth of both strains compared to each compound separately; however, only the combination with LpxC-4 met the defined criteria for synergy. These results identify a novel synergy between two antimicrobial classes against A. baumannii strains.

Conversion of methane to acetonitrile over GaN catalysts derived from gallium nitrate hydrate co-pyrolyzing with melamine, melem, or g-C3N4: The influence of nitrogen precursors

Co-pyrolyzing gallium nitrate hydrate and melamine, melem, or g-C3N4 generates gallium nitride (GaN) for the conversion of methane to acetonitrile (AcCN). The solid-state-pyrolysis-made GaN catalysts exhibited better activity than commercial...