Interaction affinity of Delta and Epsilon class glutathione-s-transferases (GSTs) to bind with DDT for detoxification and conferring resistance in Anopheles gambiae, a malaria vector.

BACKGROUND & OBJECTIVES: The enzyme glutathione-s-transferases (GSTs) are associated with detoxification of DDT, as experimentally proved in Anopheles gambiae. Insect GSTs are classified into six classes and among them Delta and Epsilon class GSTs have been implicated in detoxification of organochlorine insecticides. Both Delta and Epsilon GSTs produce, in total, 24 transcripts that result in the production of corresponding enzyme proteins. However, the conventional assay estimates the level of total GSTs and relates to development of resistance to DDT. Hence, it would be more reliable to estimate the level of the specific class GSTs that shows higher affinity with DDT. This would also lead to design a specific molecular tool for resistance diagnosis. METHODS: Of the 24 GSTs, computational models for 23 GSTs, which are available in Swiss-Prot database, were retrieved and for the remaining one, D7-2, for which no model is available in the data bank, a structural model was developed using the sequence of An. dirus B with a PDB ID of 1R5A as the template. All the models were docked with DDT in the presence of reduced glutathione. RESULTS: The energy output showed that Delta, D6 has the highest interaction affinity with DDT. Hence, this particular GST (D6) is likely to get elevated on exposure of mosquitoes to DDT. INTERPRETATION & CONCLUSION: It would be, therefore, possible to design a specific molecular assay to determine the expression level of such high affinity transcript(s) and to use for resistance diagnosis reliably in the vector surveillance programme.

Synthesis of TiO2 hollow nanofibers by co-axial electrospinning and its superior lithium storage capability in full-cell assembly with olivine phosphate.

We report the formation and extraordinary Li-storage properties of TiO2 hollow nanofibers by co-axial electrospinning in both the half-cell and full-cell configurations. Li-insertion properties are first evaluated as anodes in the half-cell configuration (Li/TiO2 hollow nanofibers) and we found that reversible insertion of ~0.45 moles is feasible at a current density of 100 mA g(-1). The half-cell displayed a good cyclability and retained 84% of its initial reversible capacity after 300 galvanostatic cycles. The full-cell is fabricated with a commercially available olivine phase LiFePO4 cathode under optimized mass loading. The LiFePO4/TiO2 hollow nanofiber cell delivered a reversible capacity of 103 mA h g(-1) at a current density of 100 mA g(-1) with an operating potential of ~1.4 V. Excellent cyclability is noted for the full-cell configuration, irrespective of the applied current densities, and it retained 88% of reversible capacity after 300 cycles in ambient conditions at a current density of 100 mA g(-1).

Synthesis and enhanced electrochemical performance of Li2CoPO4F cathodes under high current cycling.

Lithium cobalt fluorophosphate, Li(2)CoPO(4)F, is successfully synthesized by a solid state reaction under Ar flow at 700 °C. X-ray diffraction and scanning electron microscopic studies are utilized to analyze the structural and morphological features of the synthesized materials, respectively. The presence of fluorine is also supported by energy-dispersive X-ray spectroscopy. The electrochemical properties are evaluated by means of Li/Li(2)CoPO(4)F half-cell configurations in both potentiostatic and galvanostatic modes. The Li/Li(2)CoPO(4)F cell delivers an initial discharge capacity of 132 mA h g(-1) at a current density of 0.1 mA cm(-2) between 2.0 and 5.1 V at room temperature. Due to the higher operating potential of the Co(2+/3+) couple in the fluorophosphate matrix, this cell shows a capacity retention of only 53% after 20 cycles, still the material delivered 108 mA h g(-1) at a high current rate of 1 C. Cyclic voltammetric studies corroborate the insertion and extraction of Li(+) ions by a single phase reaction mechanism during cycling.

Carbon coated nano-LiTi2(PO4)3 electrodes for non-aqueous hybrid supercapacitors.

The Pechini type polymerizable complex decomposition method is employed to prepare LiTi(2)(PO(4))(3) at 1000 °C in air. High energy ball milling followed by carbon coating by the glucose-method yielded C-coated nano-LiTi(2)(PO(4))(3) (LTP) with a crystallite size of 80(±5) nm. The phase is characterized by X-ray diffraction, Rietveld refinement, thermogravimetry, SEM, HR-TEM and Raman spectra. Lithium cycling properties of LTP show that 1.75 moles of Li (~121 mA h g(-1) at 15 mA g(-1) current) per formula unit can be reversibly cycled between 2 and 3.4 V vs. Li with 83% capacity retention after 70 cycles. Cyclic voltammograms (CV) reveal the two-phase reaction mechanism during Li insertion/extraction. A hybrid electrochemical supercapacitor (HEC) with LTP as negative electrode and activated carbon (AC) as positive electrode in non-aqueous electrolyte is studied by CV at various scan rates and by galvanostatic cycling at various current rates up to 1000 cycles in the range 0-3 V. Results show that the HEC delivers a maximum energy density of 14 W h kg(-1) and a power density of 180 W kg(-1).

Size controlled synthesis of Li2MnSiO4 nanoparticles: effect of calcination temperature and carbon content for high performance lithium batteries.

Size controlled, nanoparticulate Li(2)MnSiO(4) cathodes were successfully prepared by sol-gel route. Effects of calcination temperature and carbon content (adipic acid) were studied during synthesis process. EPR study was conducted to ensure the formation of phase through oxidation state of manganese. Microscopic pictures indicate spherical shape morphology of the synthesized Li(2)MnSiO(4) nanoparticles. Transmission electron microscopic pictures confirmed the presence of carbon coating on the surface of the particles. Further, the optimization has been performed based on phase purity and its battery performance. From the optimization, 700°C and 0.2 mol adipic acid (against total metal ion present in the compound) were found better conditions to achieve high performance material. The Li(2)MnSiO(4) nanoparticles prepared in the aforementioned conditions exhibited an initial discharge capacity of ~113 mAh g(-1) at room temperature in Li/1M LiPF(6) in EC:DMC/Li(2)MnSiO(4) cell configuration. All the Li(2)MnSiO(4) nanoparticles prepared at various conditions experienced the capacity fade during cycling.