School Of Basic And Applied Sciences

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    Identifying the preferred interaction mode of naringin with gold nanoparticles through experimental, DFT and TDDFT techniques: Insights into their sensing and biological applications
    (Royal Society of Chemistry, 2016) Singh, Baljinder; Rani, Monika; Singh, Janpreet; Moudgil, Lovika; Sharma, Prateek; Kumar, Sanjeev; Saini, G.S.S.; Tripathi, S.K.; Singh, Gurinder; Kaura, Aman
    In this work, the binding behaviour of naringin-a flavonoid with AuNPs is explained by combining experimental and theoretical approaches. We have systematically analysed the effect of temperature and concentration of naringin and gold (Au) in the formation of naringin stabilized Au nanoparticles (N-AuNPs). The interaction of naringin with gold nanoparticles (AuNPs) is investigated by various techniques such as UV-visible spectroscopy, TEM, FT-IR, XRD and gel electrophoresis. These studies indicate that naringin acts as a reducing and stabilizing agent. Further, we have modelled the two side chains of naringin with the functional groups [C10H7O2] and [C6H5O]-, and identified the lowest energy configurations of these groups with AuNPs with the help of density functional theory (DFT). The [C10H7O2]-Au13 has higher binding energy than [C6H5O]--Au13 and it is attributed to delocalized molecular orbitals in [C10H7O2], hence higher charge transfer to the Au13 cluster. On the basis of the resulting structures, we examine the optical properties using time-dependent density functional theory (TDDFT). We observe significant changes in the optical spectra of the representative structures of side chains with the AuNPs. The peak in the spectra of the Vis region of [C10H7O2]-Au13 undergoes a shift towards lower wavelength in comparison to [C6H5O]--Au13. Natural transition orbitals (NTOs) of hole and particle states of the [C10H7O2]-Au13 conjugate system are localized on [C10H7O2] and Au13, respectively, whereas for the [C6H5O]--Au13 both hole and particle states are localized on the Au13 cluster. These N-AuNPs show their applicability as a sensor for detecting aluminium ions (Al3+) in aqueous solution. These NPs are also found to be biocompatible with normal red blood cells and MDAMB-231 breast carcinoma cell lines, as evaluated from hemolysis and cytotoxicity assays. Thus, naringin offers non-toxic and bio friendly N-AuNPs, which are considered to be the best vehicle for drug release and other possible biomedical and sensing applications. ? 2016 The Royal Society of Chemistry.
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    Structural, Morphological, Thermal, and Pasting Properties of Starches From Diverse Indian Potato Cultivars
    (Wiley-VCH Verlag, 2018) Singh, Narpinder; Kaur, Amritpal; Shevkani, Khetan; Ezekiel, Rajrathnam; Kaur, Prabhjot; Isono,Naoto; Noda, Takahiro
    Starches from 42 diverse Indian potato cultivars are evaluated for diversity in structural (amylose content and amylopectin chain length distribution), morphological (granules size distribution), thermal, and pasting properties. Amylose content varied between 6.5 and 32.2% while the proportion of short (DP 6?12), medium (DP 13?18), and long (DP 19?30) amylopectin chains varied in the range from 37.2 to 45.4%, 35.6 to 39.1%, and 17.8 to 24.5%, respectively. Starches with higher transition temperature showed lower enthalpy of gelatinization. The proportion of small granules (<10 ?m) correlated negatively to short amylopectin chains (DP 6?12), peak viscosity, and breakdown viscosity. Transition and pasting temperature related negatively to the proportion of short and medium chains of amylopectin (DP 6?12 and 13?18, respectively), while positively to that of long chains (DP 19?30). Peak viscosity and breakdown viscosity has a negative relation while the final and setback viscosity have a positive relation with long amylopectin chains. ? 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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    Electronic properties and STM images of vacancy clusters and chains in functionalized silicene and germanene
    (Elsevier B.V., 2017) Jamdagni, Pooja; Kumar, Ashok; Sharma, Munish; Thakur, Anil; Ahluwalia, P. K.
    Electronic properties and STM topographical images of X (=F, H, O) functionalized silicene and germanene have been investigated by introducing various kind of vacancy clusters and chain patterns in monolayers within density functional theory (DFT) framework. The relative ease of formation of vacancy clusters and chain patterns is found to be energetically most favorable in hydrogenated silicene and germanene. F- and H-functionalized silicene and germanene are direct bandgap semiconducting with bandgap ranging between 0.1?1.9?eV, while O-functionalized monolayers are metallic in nature. By introducing various vacancy clusters and chain patterns in both silicene and germanene, the electronic and magnetic properties get modified in significant manner e.g. F- and H-functionalized silicene and germanene with hexagonal and rectangle vacancy clusters are non-magnetic semiconductors with modified bandgap values while pentagonal and triangle vacancy clusters induce metallicity and magnetic character in monolayers; hexagonal vacancy chain patterns induce direct-to-indirect gap transition while zigzag vacancy chain patterns retain direct bandgap nature of monolayers. Calculated STM topographical images show distinctly different characteristics for various type of vacancy clusters and chain patterns which may be used as electronic fingerprints to identify various vacancy patterns in silicene and germanene created during the process of functionalization. ? 2016 Elsevier B.V.