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Selvamani A.,Anna University | Selvaraj M.,Anna University | Krishnan P.S.,Anna University | Gurulakshmi M.,Madras Christian College Autonomous | Shanthi K.,Anna University
Applied Catalysis A: General | Year: 2015

The Ce1-xMnxO2 nanocatalysts (x = 0, 0.25, 0.50, 0.75 and 1.0 mol. ratio) were synthesized by precipitation method using a different precursor salt. The effect of morphology with exclusive (1 0 0) plane was examined for the selective oxidation of ethylbenzene into acetophenone with maximum selectivity. The physico-chemical properties of synthesized catalysts were characterized using various techniques. The incorporation of Mnn+ into ceria lattice and the presence of (1 0 0) plane were confirmed by XRD and HRTEM analysis. The XRD patterns of Ce1-xMnxO2 catalysts were analyzed using the Rietveld refinement method to calculate the lattice parameters. Surface area and pore size distribution of the catalysts were analyzed from N2 sorption study. XPS and DR-UV-vis spectra confirm the presence of Ce3+ and Mn2+ in the ceria lattice. Further, the presence of Mn2+ in Ce1-xMnxO2 framework was confirmed from ESR technique. H2-TPR study revealed the oxygen storage capacity (OSC) of the catalysts. 3D flower-like and cubic morphology of ceria nanoparticles were confirmed from FESEM and HRTEM images, and the composition values of the elements present in the catalysts were calculated using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The catalytic activity was tested for vapor phase selective oxidation of ethylbenzene using oxygen as an oxidant at low temperature (463 K). The key reaction parameters were varied to study the stability, activity and selectivity of catalysts. The study concluded that suitable amount of manganese ion content in ceria is essential for selective oxidation of ethylbenzene at low temperature (463 K). Cubic structure Ce0.25Mn0.75O2 nanocatalyst with specific (1 0 0) plane is found to be the most suitable catalyst for high conversion and selectivity toward acetophenone under the given reaction conditions. © 2015 Elsevier B.V. All rights reserved.

Selva Kumar C.,University of Madras | Arunachalam M.,Manonmaniam Sundaranar University | Sivaramakrishnan K.G.,Madras Christian College Autonomous
Oriental Insects | Year: 2013

A new species of mayfly Choroterpes (Euthraulus) nambiyarensis sp. nov. is described from the nymphs collected in the southern Western Ghats, India. The types are deposited in the Zoological Survey of India, Kolkata, India. © 2013 Taylor & Francis.

Sathish Kumar T.,Madras Christian College Autonomous | Ramalingam K.,Mediclone Research Center
Research Journal of Pharmaceutical, Biological and Chemical Sciences | Year: 2014

This paper describes the details of vaccination trials in Penaeus monodon carried out by administering formalin-killed, virulent strains of Vibrio harveyi (VHV) and Vibrio parahaemolyticus (VPV), isolated from P. monodon with symptoms of vibriosis, as vaccines through immersion and oral (feeding) methods. The efficacy of the vaccination was evaluated in terms of relative percent survival (RPS) upon challenge with the respective live virulent strains of vibrio, total haemocyte count (THC), haemolymph phenoloxidase (PO) activity and haemolymph antibacterial activity on 7, 14 and 21 days post-vaccination (PV). It was observed that vaccination with both VHV and VPV by both immersion and oral methods induced maximum immunity in P. monodon in terms of all the parameters investigated within a short period of about 7 days PV. The increased immune response gradually declined to a lower level during the next 14 to 21 days PV. From the study, it can be concluded that P. monodon can be protected from vibriosis by oral and immersion method of vaccination in a short time of 7 days.

Kumar C.S.,Manonmaniam Sundaranar University | Sundar S.,Manonmaniam Sundaranar University | Sivaramakrishnan K.G.,Madras Christian College Autonomous
Oriental Insects | Year: 2012

Two new mayfly species belonging to the family Baetidae, namely Platybaetis arunachalae sp. nov. and Indobaetis michaelohubbardi sp. nov., are described from nymphs collected in the Ramanadi and Tamiraparani rivers, respectively, of the southern Western Ghats, Tamil Nadu, India. Generic diagnosis based on nymphs and key to known species of Platybaetis and Indobaetis are also provided. © 2012 Taylor & Francis.

Sivaramakrishnan K.G.,Madras Christian College Autonomous | Janarthanan S.,University of Madras | Selvakumar C.,University of Madras | Arumugam M.,University of Madras
Conservation Genetics Resources | Year: 2014

Ecosystem diversity, species richness and genetic diversity are the three major facets of biodiversity which deserve equal attention for conservation. However, genetic diversity is significant in identification of unique populations for conservation purpose. Aspects of DNA barcoding, loss of genetic diversity in cryptic species and examples of molecular phylogenetic and molecular phylogeographic studies on aquatic insects of headwaters from major biogeographic realms are briefly reviewed in the light of prioritization of taxa and habitats for conservation. Special emphasis is laid on identification of evolutionary significant units for effective conservation in the context of global climate change. Current methodologies for identifying potential loss of intraspecific genetic diversity are also highlighted with suggestions on future research priorities. © 2014, Springer Science+Business Media Dordrecht.

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