Influence of Preparation Procedure on Physicochemical and Antibacterial Properties of Titanate Nanotubes Modified with Silver.

Silver nanoparticles (NPs) are effective antibacterial agents; however, aggregation of NPs and uncontrolled release of Ag+ affect their efficiency and may pose a risk to the environment. To overcome these disadvantages, immobilization of Ag onto titanate nanotubes (TNTs) was investigated. This paper describes the physicochemical and antibacterial properties of silver incorporated titanate nanotubes (Ag/TNTs) prepared using five procedures and containing different Ag amounts (0.11-30.85 wt.%). The methods were (i) sol-gel followed by a hydrothermal process; (ii) photodeposition under ambient conditions; (iii) photodeposition under an inert atmosphere; (iv) NaBH4 reduction; and (v) electroless deposition after activation of TNTs with Sn2+. Depending on the synthesis procedure, the presence of metallic Ag NPs, AgO or AgCl was observed. The electroless method led to an additional deposition of SnO2 NPs. The antibacterial properties of Ag/TNTs were analyzed as a function of Ag content and released against Escherichia coli and Staphylococcus epidermidis. The best bactericidal properties exhibited Ag/TNTs prepared through the photodeposition process due to the higher interaction of exposed Ag NPs with bacteria. An increase of Ag loading resulted in improvement of antibacterial activity of Ag/TNTs although no direct correlation between silver content or release and inhibition of bacterial growth was found.

Hydrothermal synthesized magnetically separable mesostructured H2Ti3O7/γ-Fe2O3 nanocomposite for organic dye removal via adsorption and its regeneration/reuse through synergistic non-radiation driven H2O2 activation.

Hydrogen titanate (H2Ti3O7) nanotubes/nanosheets (HTN) are emerging class of adsorbent material which possess unique property of activating hydrogen peroxide (H2O2) to generate the reactive oxygen species (ROS), such as superoxide radical ions (O2.-) and hydroxyl radicals (·OH), effective in the decomposition of surface-adsorbed dye. However, HTN are non-magnetic which create hurdle in their effective separation from the treated aqueous solution. To overcome this issue, magnetic nanocomposites (HTNF) composed of HTN and maghemite (γ-Fe2O3) nanoparticles have been processed by subjecting the core-shell magnetic photocatalyst consisting of γ-Fe2O3/silica (SiO2)/titania (TiO2), having varying amounts of TiO2 in the shell to the hydrothermal conditions. HTNF-5 magnetic nanocomposite consisting of 31 wt% H2Ti3O7, typically having nanotube morphology with the highest specific surface area (133 m2 g-1) and pore-volume (0.22 cm3 g-1), exhibits the highest capacity (74 mg g-1) for the adsorption of cationic methylene blue (MB) dye from an aqueous solution involving the electrostatic attraction mechanism and pseudo-second-order kinetics. Very fast magnetic separation followed by regeneration of HTNF-5 magnetic nanocomposite has been demonstrated via non-radiation driven H2O2 activation. It has been ascertained for the first time that the underlying mechanism of dye decomposition involves the synergy effect between the constituents of HTNF magnetic nanocomposite.

Role of CYP2C19 gene polymorphism in acute alcohol withdrawal treatment with loading dose of diazepam in a South Indian population.

PURPOSE: Alcohol dependence is a public health problem worldwide, commonly associated with withdrawal symptoms for which diazepam is a frequently used drug. We studied the effect of CYP2C19 gene polymorphisms on diazepam loading dose requirement and time to reversal of acute alcohol withdrawal symptoms. We also studied the influence of the polymorphism in this gene on the persistent symptoms after loading dose of diazepam. METHODS: Sixty-nine patients who reported to the psychiatry department with symptoms of alcohol withdrawal diagnosed by DSM-IV criteria were included for the study. A 10-mg loading dose of diazepam was administered iv after baseline assessment of withdrawal severity using CIWA-Ar scoring. The patients were assessed for improvement of the symptoms every two hourly and 20 mg oral diazepam was given based on improvement of symptoms. Genotyping for CYP2C19*2, CYP2C19*3 and CYP2C19*17 was done by PCR-RFLP and RT-PCR methods. RESULTS: The diazepam dose requirement as well as the time required for reversal of acute symptoms was not statistically different among the different genotype groups. Similarly, the frequency of patients with persistent symptoms after successful treatment of the acute episode was not different among the groups. However, the total diazepam dose requirement was influenced by baseline CIWA-Ar scores (adjusted OR 0.21, p = 0.026). In addition, the odds of treatment with a lower dose (10 mg) of diazepam were higher in smokers (adjusted OR 5.22, p = 0.025) and patients with other addiction (adjusted OR 9.26, p = 0.026). CONCLUSION: We found that CYP2C19 polymorphism did not have any significant effect on the diazepam dose requirement, time duration needed for successful treatment or on the persistent symptoms after loading dose of diazepam in South Indian population. However, diazepam dose requirement was influenced by baseline CIWA-Ar score, smoking status and other comorbid addictions.