DNA nanostructures based biosensor for the determination of aromatic compounds.

Graphite electrode was modified using multi-walled carbon nanotubes (MWCNT), chitosan (CS), glutaraldehyde (GTA) and DNA nanostructures (nsDNA). DNA nanostructures of 50 nm in size were produced from single DNA template sequence using a simple two step procedure and were confirmed using TEM and AFM analysis. The modified electrode was applied to the electrochemical detection of aromatic compounds using EIS. The modified electrode was characterized using differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). For comparison, electrochemical results derived from single stranded (50 bp length) and double stranded (50 bp length) DNA based biosensors were used. The results indicate that the modified electrode prior to nsDNA immobilization provides a viable platform that effectively promotes electron transfer between nsDNA and the electrode. The mode of binding between the nsDNA and aromatic compounds was investigated using EIS, indicating that the dominant interaction is non-covalent. nsDNA based biosensor was observed to act as an efficient biosensor in selective and sensitive identification of aromatic compounds.

Vermicomposting of Solid Waste Using Local and Exotic Earthworms: A Comparative Study.

The aim of this study was to assess the decomposition efficiency of earthworms, local (L.mauritii) as well as exotic (Eisenia foetida) in vermicomposting of garden litter in SRM University campus. The vermicompost produced through vermicomposting of garden litter mixed with cow dung in the ratio of 3:1 by using local and exotic earthworms (Eisenia foetida) was rich in ammoniacal nitrogen, nitrate nitrogen, available phosphorus, total potassium and TKN, and there was a reduction in total organic carbon and carbon to nitrogen ratio. The study reveals that the decomposition efficiency of exotic earthworms is better compared to local earthworms.

Nonisothermal kinetics analysis of the dehydration of ziprasidone hydrochloride monohydrate by thermogravimetry.

In the current work the kinetics of dehydration of ziprasidone hydrochloride monohydrate was studied by nonisothermal thermogravimetry. Ziprasidone hydrochloride monohydrate was heated from 30 to 150° with a heating rate of 5° per min under nitrogen gas atmosphere and weight loss data were collected. Powder X-ray difraction was used to characterize the solid before and after dehydration. The well accepted Coats-Redfern model fitting approach was applied to the thermogravimetry data for the kinetic analysis. Thirteen solid state reaction models were studied; among them one-dimensional diffusion model was found to be the best fit model for this reaction with an excellent correlation 0.9994. The Arrhenius parameters, activation energy, and pre-exponential factor were determined, the values were found to be 28 k.cal/mol and 9.53×10(13) sec(-1), respectively.