Panneerselvam M.,Loyola College |
Panneerselvam M.,Loyola Institute of Frontier Energy LIFE |
Kathiravan A.,University of Madras |
Solomon R.V.,Madras Christian College Autonomous |
And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2017
A recently reported triphenylamine (TPA) group in conjugation with a benzothiadiazole (BTD) moiety opens up the possibility for designing new organic sensitizers for solar cell applications that are amenable for structural tuning. Hence, seven new TPA molecules were designed from two experimentally reported molecules. The optoelectronic properties, including the absorption and emission spectra of the TPA derivatives, were studied via density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. Different π-linkers were screened to understand the role of π-linkers in altering the optoelectronic properties of these molecules. Our results show that furan moieties bring planarity to the molecule and show reduced HOMO-LUMO gaps. All these molecules show excellent delocalization of π-electrons. TDDFT calculations show that furan-substituted TPA (TPA9) has the highest absorption maxima. Interestingly, the thiophene-substituted TPA (TPA7) was found to have a high emission maxima as it achieved planarity in the excited state. There is an excellent correlation observed between the computed optoelectronic properties and calculated HOMO-LUMO gaps. Overall, this study throws light on the role of π-linkers in the photophysical properties of TPA derivatives and provides useful clues in designing new molecules for optoelectronic applications. © the Owner Societies 2017.
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.
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.
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.
Ramakrishnan R.,Anna University |
Wilson P.,Madras Christian College Autonomous |
Sivakumar T.,Anna University |
Jemina I.,Hindustan University
Ceramics International | Year: 2013
Nano-sized calcium hydroxyapatite, [Ca10(PO4) 6(OH)2] has been synthesized by the sol-gel combustion method using calcium nitrate and di-ammonium hydrogen phosphate as precursors in the aqueous medium. Triethyl phosphite was used as a phosphate precursor for alcohol mediated combustion. The aqueous and alcohol media were employed for the investigation of combustion synthesis in the presence of various fuels such as urea, glycine, alanine, hydrazine and hexamine. The metal-to-fuel ratio in the synthesis was maintained at 1 to facilitate complete combustion and the Ca/P ratio was maintained at 1.67 to aid the stoichiometric formation of hydroxyapatite. The combustion products were calcined at 800 °C for 10 h and were characterized by powder XRD, FT-IR, HR-SEM and HR-TEM techniques. All the five fuels used under the alcohol mediated combustion, resulted in forming phase pure hydroxyapatite; whereas the aqueous mediated combustion method yielded biphasic calcium phosphate containing Ca10(PO4) 6(OH)2 and β-TCP depending on the nature of the fuel. © 2012 Elsevier Ltd and Techna Group S.r.l.
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.
Thirunavukkarasu N.,Madras Christian College Autonomous |
Dhinamala K.,Madras Christian College Autonomous |
Moses Inbaraj R.,Madras Christian College Autonomous
Journal of Chemical and Pharmaceutical Research | Year: 2011
Many multinational pharmaceutical companies are producing chitin products in a commercial scale. The crustacean (crab and shrimp) shell wastes are also utilized for this production. Only limited works are available about the crustacean stomatopods pertaining to the chitin extraction. Due to the lacunae in this field the present study had been carried out to extract chitin from the marine stomatopods Orotosquilla quinquedentata and O.nepa. The yield of chitin was more in Oratosquilla nepa where 20g of the shell yielded 2.145g of chitin with percentage contribution of 10.725%. The FT-IR spectrum of chitin was also confirming the presence of chitin in the shell of stomatopods. The results of the present investigation paves way and provides concrete information for the utilization of chitin in the development of drugs, artificial bone and raw material for the food industries in the near future.
Michael C.,Madras Christian College Autonomous |
Sugumar R.W.,Madras Christian College Autonomous
Oriental Journal of Chemistry | Year: 2013
One of the global problems in the present day world is the negative impacts created by the growing e-waste on the natural resources like air, soil and water In the present work, the discarded electronic components were allowed to leach in water samples drawn from different rivers and the leachate were analyzed for the presence of heavy metals. The results highlight that even if the contact time is short, the toxic elements tend to leach to a great extent. In our studies, Arsenic had leached to an extent of 0.O53ppm, Cadmium 0.010 ppm, Chromium 0.029 ppm, Lead 0.O42ppm and Mercury 0.061 ppm. The results indicate that most of the metals have a tendency to leach and the extent of leaching depends on the quality of the water As a result of leaching the physicochemical parameters like pH, hardness, conductance and TDS of the water samples underwent a change. On the other hand, the physical parameters like viscosity, density, were not much affected. These studies highlight the danger of dumping the discarded electronic components in river beds especially when the water flow is less and when the water is stagnated.
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.
Vasudhevan S.,Kendriya Vidyalaya DGQA |
Vasudhevan S.,Madras Christian College Autonomous |
Joel Karunakaran R.,Madras Christian College Autonomous
International Journal of ChemTech Research | Year: 2013
Twelve 2,3-Dihydroquinazolinone derivatives were synthesized and were identified by spectral analysis. All the synthesized compounds of 2,3- Dihydroquinazolinone derivatives were screened for their antibacterial activities against two gram positive bacterial strains Staphylococcus aureus and Bacillus subtilis and two gram negative bacterial strains Escherichia coli and Pseudomonas aeruginosa were used for antibacterial study. Antifungal activity was also studied against Candida albicans and Aspergillus niger.The standard antibacterial and antifungal agents used were Amikacin and ketoconalzole respectively. The antimicrobial screening studies revealed that compounds 3d,3e,3f,3k &3l showed moderately high activity against B.subtilis and P.aeruginosa and moderate activity against S. aureus. The antifungal screening studies revealed that 3a,3b,3i&3j showed mild activity against Candida albicans and Compounds 3e& 3j showed excellent activity against Asperigillus niger comparable to the standard drug Ketaconazole. The enhanced activity of 3j against Asperigillus niger may be due to the presence of two methoxyl groups at 3, 4 position which are with the electron donating behaviour.