Kiran Gupta

Photocatalytic antibacterial performance of TiO2 and Ag-doped TiO2 against S. aureus. P. aeruginosa and E. coli

Summary This paper reports the structural and optical properties and comparative photocatalytic activity of TiO2 and Ag-doped TiO2 nanoparticles against different bacterial strains under visible-light irradiation. The TiO2 and Ag-doped TiO2 photocatalysts were synthesized by acid catalyzed sol–gel technique and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–vis spectroscopy and photoluminescence (PL). The XRD pattern revealed that the annealed sample of TiO2 has both anatase and rutile phases while only an anatase phase was found in Ag-doped TiO2 nanoparticles. The decreased band-gap energy of Ag-doped TiO2 nanoparticles in comparison to TiO2 nanoparticles was investigated by UV–vis spectroscopy. The rate of recombination and transfer behaviour of the photoexcited electron–hole pairs in the semiconductors was recorded by photoluminescence. The antimicrobial activity of TiO2 and Ag-doped TiO2 nanoparticles (3% and 7%) was investigated against both gram positive (Staphylococcus aureus) and gram negative (Pseudomonas aeruginosa, Escherichia coli) bacteria. As a result, the viability of all three microorganisms was reduced to zero at 60 mg/30 mL culture in the case of both (3% and 7% doping) concentrations of Ag-doped TiO2 nanoparticles. Annealed TiO2 showed zero viability at 80 mg/30 mL whereas doped Ag-TiO2 7% showed zero viability at 40 mg/30 mL culture in the case of P. aeruginosa only.

Filarial pleural effusion.

A 30-year-old man from Bihar (a north-eastern state in India) presented with complaints of breathlessness, a dry cough and left-sided chest pain for the previous 15 days. On physical examination, left-sided pleural effusion was present and vocal resonance was decreased. On clinical investigation, haemogram showed haemoglobin 10 g%, total leucocyte count 8700/mm and 14% eosinophils on differential leucocyte count. Erythrocyte sedimentation rate was 20mm in the first hour by Westergren method and Mx test was negative. Chest X-ray revealed left-sided pleural effusion and prominent broncho-alveolar markings. Ultrasonography thorax also revealed left-sided pleural effusion. Diagnostic pleural tap was performed. Straw-coloured, blood-stained fluid was aspirated and subjected to biochemical, microbiological and cytological examinations. Protein was 5.0 gm/dL and sugar 110mg/ dL. Aerobic and anaerobic cultures did not grow any organism (Figure 1). The microscopic examination of pleural fluid after centrifugation showed numerous larvae of Wuchereria bancrofti. Peripheral blood film examination did not reveal any microfilariae, diurnal as well as nocturnal, on three occasions.

Synthesis and Structure of an Aluminum Bis(3-chloropentanedionate) Isopropoxide: [Al(µ-OiPr)(3-Clacac)2]2

1A [Al(OiPr)3]4 was reacted at ambient temperature with 3-chloropentanedione (3-ClacacH) in 1 : 1 molar ratio in toluene, to obtain the mono-substituted product. However, the bis-substituted dinuclear tetrakis(3-chloropentanedionato)-di-m-isopropoxy-dialuminum(III) [Al(μ-OiPr)(3-Clacac)2]2 () was isolated in 46% yield upon aging of the reaction mixture at −10 °C. The supernatant upon aging yielded a crop of tris-3-chloroacetylacetonate Al(3-Clacac)3·H2O (1) in 13% yield. Complexes 1A (monoclinic, space group P21/c with Z = 2) and 1(cubic, space group P43n with Z = 8) were characterized by elemental analyses, NMR and IR spectroscopy and single-crystal X-ray crystallography. Graphical Abstract Synthesis and Structure of an Aluminum Bis(3-chloropentanedionate) Isopropoxide: [Al(μ-OiPr)(3-Clacac)2]2