Structural, optical and antibacterial activity of pure and co-doped (Fe & Ni) tin oxide nanoparticles

In this investigation, ferric (Fe) and nickel (Ni) co-doped tin oxide (SnO₂) nanoparticles structural, optical, morphological, and antibacterial characteristics were synthesised, characterised, and examined. By employing SnCl₂·2H₂O and the transition metal precursors FeCl₃ and NiCl₂·6H₂O with various Fe/Ni molar ratios, thermal annealing was carried out at a high temperature (700 °C). X-ray diffraction (XRD), UV-Visible spectroscopy, Photoluminescence (PL), FT-IR, and scanning electron microscopy (SEM) with energy dispersive X-ray techniques (EDX) were used to examine the materials' structural, chemical, optical, morphological, and anti-microbial capabilities. The average particle size of pure and co-doped SnO₂ nanoparticles was determined to be around 52 nm and 15 nm, and SnO₂ crystallites were observed to present tetragonal rutile structure with space group P_42/mmm (No.136). Metal ions were replaced in the Sn lattice, as shown by Fe and Ni co-doped SnO₂ nanoparticles. Pure and co-doped samples have capsule and sphere-like features in their SEM morphology. Using UV-visible diffuse reflectance spectroscopy, the optical property was examined, and it was observed that the band gaps for pure and co-doped SnO₂ were 3.73 eV and 3.53 eV, respectively. The functional groups and incorporation of Fe and Ni in the prepared powder were also validated by FT-IR and EDX studies. By utilising the agar well diffusion technique and Nutrient agar, the antibacterial properties of pure, Ni-Fe co-doped SnO₂ nanoparticles annealed at 700 °C were assessed. They were evaluated against various Gram-positive bacteria (Staphylococcus pheumoniae) and Gram-negative bacteria (Shigella dysenteria). The zone of incubation was found against the Gram +Ve and Gram -Ve bacterial strains.

Clinical characteristics & outcome of SARS-CoV-2 infected neonates presenting to paediatric emergency

Background & objectives

Data on neonatal COVID-19 are limited to the immediate postnatal period, with a primary focus on vertical transmission in inborn infants. This study was aimed to assess the characteristics and outcome of COVID-19 in outborn neonates.

Methods

All neonates admitted to the paediatric emergency from August 1 to December 31, 2020, were included in the study. SARS-CoV-2 reverse transcription- (RT)-PCR test was done on oro/nasopharyngeal specimens obtained at admission. The clinical characteristics and outcomes of SARS-CoV-2 positive and negative neonates were compared and the diagnostic accuracy of a selective testing policy was assessed.

Results

A total of 1225 neonates were admitted during the study period, of whom SARS-CoV-2 RT-PCR was performed in 969. The RT-PCR test was positive in 17 (1.8%). Mean (standard deviation) gestation and birth weight of SARS-CoV-2-infected neonates were 35.5 (3.2) wk and 2274 (695) g, respectively. Most neonates (11/17) with confirmed COVID-19 reported in the first two weeks of life. Respiratory distress (14/17) was the predominant manifestation. Five (5/17, 29.4%) SARS-CoV-2 infected neonates died. Neonates with COVID-19 were at a higher risk for all-cause mortality [odds ratio (OR): 3.1; 95% confidence interval (CI): 1.1-8.9, P=0.03]; however, mortality did not differ after adjusting for lethal malformation (OR: 2.4; 95% CI: 0.7-8.7). Sensitivity, specificity, accuracy, positive and negative likelihood ratios (95% CI) of selective testing policy for SARS-CoV-2 infection at admission was 52.9 (28.5-76.1), 83.3 (80.7-85.6), 82.8 (80.3-85.1), 3.17 (1.98-5.07), and 0.56 (0.34-0.93) per cent, respectively.

Interpretation & conclusions

SARS-CoV-2 positivity rate among the outborn neonates reporting to the paediatric emergency and tested for COVID-19 was observed to be low. The selective testing policy had poor diagnostic accuracy in distinguishing COVID-19 from non-COVID illness.