Narrow Results

A $4\times 4\times 4$ and 765eV (sufficient to converge the results) have been used to explore the electronic, optical, mechanical, and vibrational properties using ab initio code CASTEP with hybrid functionals. A wide indirect F–Z bandgap energy of 3.77eV has been reported. Our partial density of states plot further shows the valence band is made of O 2p and Ag 4d electron orbitals, while Ag S orbitals and N O 2p states contribute to the conduction band bottom (CBM), among the upper conduction band consisting of Ag 4p, O 2$s2p$ and N 2p electron orbitals. In our optical data, a high absorption coefficient of $2.57\times 10^5$ cm${}^{-1}$ has been found, and a relatively low 20% reflectivity simply indicates a high absorption of the material. Although our mechanical data cannot determine the material ductility/brittleness with the B/G ratio, we can report a Poisson’s ratio value of −2.04 in this work. On the other hand, the phonon dispersion and the density of the phonon state plot report may indicate the mechanical instability of the system. The negative Poisson’s ratio (NPR) we provide may hint at the possibility of using AgNO₃ as a promising anode in a group I/II elements (Mg, K, Na)-ion battery.

Silver nanoparticles (AgNPs) have been synthesized by chemical reduction method using ascorbic acid as reducing agent. Silver nitrate (AgNO${}_3)$ and sodium dodecyl sulfate (SDS) have been used as precursor and stabilizer, respectively. The prepared samples were characterized by UV-visible spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The antibacterial activity of prepared silver nanoparticles has been assessed by using the disc diffusion method against pathogenic, gram-negative bacterial strains including Escherichia coli and Pseudomonassp. To evaluate the potential antibacterial properties of AgNPs, the discs have been impregnated and dried with three different doses like 50, 100 and 150$\mu$l of 20$\mu$g/ml concentrated AgNPs solution and placed on the Petri-dishes. The antibiotic kanamycin (5$\mu$g) was used as control. In all the cases, a clear and distinct zone of inhibition is observed, which suggests that AgNPs can be used as effective growth inhibitors of various bacterial species and would be promising candidate for future development of antibacterial agents.

The achievement of this research was to study the influence of AgNPs on the life stages of Muscadomestica. The supernatant of Trichodermaharzianum successfully reduces AgNO₃ into AgNPs through the duration of incubation, as noticed by the color change from white to red. The absorbance of UV–visible light results in an absorbance peak at 418 nm for nanoparticle solutions of Ag particles. The scanning electron microscopy (SEM) image confirmed the formation of AgNPs with an average particle size of 46.63 nm without aggregation or adhesion. The microscopy of energy-dispersive X-ray (EDX) approved the formation of AgNPs with a high amount of some atoms of carbon and oxygen derivatives from components of fungus extract used to reduce AgNO₃. The concentration of AgNPs prepared with serial dilutions of 5%, 10%, 15%, 20% and 25%, also with sterilized distilled water as a control and the influence of AgNPs on phases of $M.$domestica had been studied. The eggs of the studied insects were affected by 20% of AgNPs, which showed an increase in incubation time of 11 h without any hatched eggs at 25%. The larval stage of the insect was also influenced by AgNPs solution, which at 25% increased the duration of incubation to reach 11 h with 27 larval insects dead, compared with 7 h without any missing membrane in the larval stage of the insect. As well as the pupal phase of insects, we increased the period of incubation to 10 h with 7 h in control, and in addition, the number of pupal insects dead reached 23 in 25% concentration. Finally, the AgNPs also increased the number of adult insects to reach 27 at 25% concentration. The AgNPs approved the activity toward $M.$domestica and therefore considered it a preferable option for biological control.