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Krishnamoorthy K.,Mepco Schlenk Engineering College, Sivakasi | Krishnamoorthy K.,Jeju National University | Manivannan G.,Nmss Vellaichamy Nadar College | Kim S.J.,Jeju National University | And 2 more authors.
Journal of Nanoparticle Research | Year: 2012

Antibacterial activity of MgO nanoparticles (NPs) was evaluated against the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa as well as the Gram-positive bacterium Staphylococcus aureus by microtitre plate-based assay incorporating resazurin as an indicator of cell growth. MgO NPs exhibited antibacterial activity with minimal inhibitory concentration of 500 μg/mL against E. coli and 1,000 μg/mL for P. aeruginosa and S. aureus. MgO NPs enhanced ultrasound-induced lipid peroxidation in the liposomal membrane. It was suggested that the mechanism of the antibacterial activity of the MgO NPs relied on the presence of defects or oxygen vacancy at the surface of the nanoparticle which led to the lipid peroxidation and reactive oxygen species generation. © Springer Science+Business Media B.V. 2012.


Vijayan C.,Nmss Vellaichamy Nadar College | Pandiaraman M.,Nehru Memorial College | Soundararajan N.,Madurai Kamaraj University | Gnanadurai P.,Nmss Vellaichamy Nadar College | Chandramohan R.,Sree Sevugan Annamalai College
International Journal of ChemTech Research | Year: 2014

Semiconducting silver selenide telluride (Ag2Se0.2Te0.8) ternary thin films of different thickness were vacuum deposited on well cleaned glass substrate at a pressure of 2 ×10-5mbar and at a deposition rate of 0.2 nm/sec at room temperature. X-ray diffraction studies revealed that thin films of lower thickness were amorphous and at higher thickness they were polycrystalline in nature with orthorhombic structure. The film crystallinity increased with increase of thickness. The PL spectra of Ag2Se0.2Te0.8bulk and thin films revealed that there is a strong emission band at 751 nm and it is independent of thickness. The topography of the thin film was studied using atomic force microscopy.


Puvaneswari S.,EMG Yadava Womens College | Rajeswarapalanichamy R.,Nmss Vellaichamy Nadar College | Sudha Priyanga G.,Nmss Vellaichamy Nadar College
Materials Chemistry and Physics | Year: 2015

The structural stability, electronic structure, elastic and superconducting properties of noble metal nitrides MN2 (M = Ru, Rh, Pd) are investigated in tetragonal (P4/mbm), fluorite (Fm3m), orthorhombic (Pnnm), pyrite (Pa-3) and hexagonal (P6/mmm) phases using first principles calculations. The calculated lattice parameters are in good agreement with other theoretical results. Among the considered structures, RhN2 and PdN2 are found to be most stable in tetragonal structure, whereas RuN2 is stable in fluorite structure. A sequence of structural phase transition is predicted under high pressure in these metal nitrides. The electronic structure reveals that these nitrides are metallic. These metal nitrides are found to be covalent, ionic and metallic in the stable phase. The observations show that these metal nitrides are mechanically stable at ambient condition. The superconducting transition temperatures for RuN2, RhN2 and PdN2 are found to be 1.65 K, 5.01 K and 8.7 K respectively. © 2014 Elsevier B.V. All rights reserved.


Premanathan M.,Mepco Schlenk Engineering College, Sivakasi | Karthikeyan K.,Mepco Schlenk Engineering College, Sivakasi | Karthikeyan K.,Jeju National University | Jeyasubramanian K.,Mepco Schlenk Engineering College, Sivakasi | Manivannan G.,Nmss Vellaichamy Nadar College
Nanomedicine: Nanotechnology, Biology, and Medicine | Year: 2011

Nanoparticles are increasingly recognized for their utility in biological applications including nanomedicine. The present study investigated the toxicity of zinc oxide (ZnO) nanoparticles toward prokaryotic and eukaryotic cells. Cytotoxicity of ZnO to mammalian cells was studied using human myeloblastic leukemia cells (HL60) and normal peripheral blood mononuclear cells (PBMCs). Antibacterial activity of ZnO was also tested against the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, as well as the Gram-positive bacterium Staphylococcus aureus, and the effect was more pronounced with the Gram-positive than the Gram-negative bacteria. ZnO nanoparticles exhibited a preferential ability to kill cancerous HL60 cells as compared with normal PBMCs. The nanoparticles enhanced ultrasound-induced lipid peroxidation in the liposomal membrane. The work suggested two mechanisms underlying the toxicity of ZnO: (i) involvement of the generation of reactive oxygen species (ROS) and (ii) induction of apoptosis. The work also revealed potential utility of ZnO nanoparticles in the treatment of cancer, for their selective toxicity to cancer cells. From the Clinical Editor: The toxicity of zinc oxide to bacteria was related to the generation of reactive oxygen species and to the induction of apoptosis. Interestingly, these effects were differentially greater in human myeloblastic leukemia cells (HL60) than normal peripheral blood mononuclear cells. © 2011 Elsevier Inc.


Santhosh M.,Nmss Vellaichamy Nadar College | Rajeswarapalanichamy R.,Nmss Vellaichamy Nadar College
Journal of Physics and Chemistry of Solids | Year: 2016

The structural stability of Alkali metal hydrides AMH4 (A=Li, Na; M=B, Al) is analyzed among the various crystal structures, namely hexagonal (P63mc), tetragonal (P42/nmc), tetragonal (P-421c), tetragonal (I41/a), orthorhombic (Pnma) and monoclinic (P21/c). It is observed that, orthorhombic (Pnma) phase is the most stable structure for LiBH4, monoclinic (P21/c) for LiA1H4, tetragonal (P42/nmc) for NaBH4 and tetragonal (I41/a) for NaAlH4 at normal pressure. Pressure induced structural phase transitions are observed in LiBH4, LiAlH4, NaBH4 and NaAlH4 at the pressures of 4 GPa, 36.1 GPa, 26.5 GPa and 46 GPa respectively. The electronic structure reveals that these metal hydrides are wide band gap insulators. The calculated elastic constants indicate that these metal hydrides are mechanically stable at normal pressure. © 2015 Elsevier Ltd.

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