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Salt Lake, India

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Salt Lake, India
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Cao Y.X.,Shanghai JiaoTong University | Chakrabortty B.,se National Center | Barker G.C.,UK Institute of Food Research | Mehta A.,se National Center | Wang Y.J.,Shanghai JiaoTong University
EPL | Year: 2013

In this letter, we present the first experimental study of bridge structures in three-dimensional dry granular packings. When bridges are small, they are predominantly "linear", and have an exponential size distribution. Larger, predominantly "complex" bridges, are confirmed to follow a power-law size distribution. Our experiments, which use X-ray tomography, are in good agreement with the simulations presented here, for the distribution of sizes, end-to-end lengths, base extensions and orientations of predominantly linear bridges. Quantitative differences between the present experiment and earlier simulations suggest that packing fraction is an important determinant of bridge structure. © Copyright EPLA, 2013.

Upadhyay R.K.,Shiv Nadar University | Soin N.,University of Bolton | Bhattacharya G.,Shiv Nadar University | Saha S.,se National Center | And 2 more authors.
Materials Letters | Year: 2015

Abstract Grapes (Vitis vinifera) extract was explored as a "green reducing agent" for the preparation of reduced graphene oxide (RGO) from graphene oxide (GO). The effect of reduction time on physical, chemical and optical properties of the RGO was also investigated. Synthesized RGO samples exhibited excellent activity as an adsorbent for the removal of organic dye. Proposed synthesis is environmental friendly, cost effective and promising for the large scale production of RGO. © 2015 Elsevier B.V.

Sardar S.,se National Center | Chaudhuri S.,se National Center | Kar P.,se National Center | Sarkar S.,se National Center | And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2015

In recent times, significant achievements in the use of zinc oxide (ZnO) nanoparticles (NPs) as delivery vehicles of cancer drugs have been made. The present study is an attempt to explore the key photoinduced dynamics in ZnO NPs upon complexation with a model cancer drug protoporphyrin IX (PP). The nanohybrid has been characterized by FTIR, Raman scattering and UV-Vis absorption spectroscopy. Picosecond-resolved Förster resonance energy transfer (FRET) from the defect mediated emission of ZnO NPs to PP has been used to study the formation of the nanohybrid at the molecular level. Picosecond-resolved fluorescence studies of PP-ZnO nanohybrids reveal efficient electron migration from photoexcited PP to ZnO, eventually enhancing the ROS activity. The dichlorofluorescin (DCFH) oxidation and no oxidation of luminol in PP/PP-ZnO nanohybrids upon green light illumination unravel that the nature of ROS is essentially singlet oxygen rather than superoxide anions. Surface mediated photocatalysis of methylene blue (MB) in an aqueous solution of the nanohybrid has also been investigated. Direct evidence of the role of electron transfer as a key player in enhanced ROS generation from the nanohybrid is also clear from the photocurrent measurement studies. We have also used the nanohybrid in a model photodynamic therapy application in a light sensitized bacteriological culture experiment.

Shinde D.P.,se National Center | Mehta A.,Allahabad University | Mishra R.K.,se National Center
EPL | Year: 2011

In an experiment involving semantic search, the visual movements of sample populations subjected to visual and aural input were tracked in a taskless paradigm. The probability distributions of saccades and fixations were obtained and analyzed. Scale-invariance was observed in the saccadic distributions, while the fixation distributions revealed the presence of a characteristic (attentional) time scale for literate subjects. A detailed analysis of our results suggests that saccadic eye motions are an example of Levy, rather than Brownian, dynamics. © Europhysics Letters Association, 2011.

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