Sreejith L.,National Institute of Technology Calicut |
Parathakkat S.,National Institute of Technology Calicut |
Nair S.M.,Malabar Christian College |
Kumar S.,M. S. University of Baroda |
And 3 more authors.
Journal of Physical Chemistry B | Year: 2011
A micelle-vesicle transition induced by n-octanol C8OH was observed in an aqueous cetyltrimethylammonium bromide (CTAB)/potassium bromide (KBr) system. This transition was investigated by viscosity, rheology, dynamic light scattering (DLS), and direct imaging technique, cryo-transmission electron microscopy (cryo-TEM). Viscometry shows that the system underwent several morphological transitions with the increase in concentration of C8OH (regions I-IV). At low octanol concentration (region I), DLS analysis showed an increase in the apparent hydrodynamic diameter of the micelles with the addition of C8OH which was supported by cryo-TEM and rheology. With further addition of C8OH, transition of the elongated micelles occurred to a viscoelastic fluid comprising entangled wormlike micelles (region II), for which rheological data can be described by the Maxwell model. Further, the wormlike micelles transform to vesicles at [C8OH] ≈ 0.020 M (region III). This transition and the consequent changes in the fluid response can be explained in terms of vesicle formation caused by further addition of C 8OH. Beyond this concentration (region IV), vesicles are the predominant microstructures in the system which shows unusual temperature response. © 2010 American Chemical Society.
Dhanaraj P.V.,Malabar Christian College |
Rajesh N.P.,SSN College of Engineering
Advanced Materials Research | Year: 2013
Nonlinear optical materials 2-aminopyridinium trifluoroacetate and bis(2- aminopyridinium) sulfate, were synthesized and single crystals were grown from aqueous solution employing the technique of controlled evaporation. The solubility and metastable zone width were found. The crystal structure was analyzed to reveal the molecular arrangements and the formation of hydrogen bonds in the crystal. High-resolution X-ray diffraction rocking curve measurements were performed to analyze the structural perfection of the grown crystals. Functional groups were identified and thermal behaviour and stability were studied. Mechanical and dielectric properties of crystals were analyzed. Optical studies reveal that both crystals have good transparency window. The nonlinear optical parameters of crystals were derived. © (2013) Trans Tech Publications, Switzerland.
Seal A.,Indiana University Bloomington |
Passi A.,Council of Scientific and Industrial Research |
Abdul Jaleel U.C.,Malabar Christian College |
Wild D.J.,Indiana University Bloomington |
Consortium O.S.D.D.,Council of Scientific and Industrial Research
Journal of Cheminformatics | Year: 2012
Experimental screening of chemical compounds for biological activity is a time consuming and expensive practice. In silico predictive models permit inexpensive, rapid "virtual screening" to prioritize selection of compounds for experimental testing. Both experimental and in silico screening can be used to test compounds for desirable or undesirable properties. Prior work on prediction of mutagenicity has primarily involved identification of toxicophores rather than whole-molecule predictive models. In this work, we examined a range of in silico predictive classification models for prediction of mutagenic properties of compounds, including methods such as J48 and SMO which have not previously been widely applied in cheminformatics. Results: The Bursi mutagenicity data set containing 4337 compounds (Set 1) and a Benchmark data set of 6512 compounds (Set 2) were taken as input data seta in this work. A third data set (Set 3) was prepared by joining up the previous two sets. Classification algorithms including Naïve Bayes, Random Forest, J48 and SMO with 10 fold cross-validation and default parameters were used for model generation on these data sets. Models built using the combined performed better than those developed from the Benchmark data set. Significantly, Random Forest outperformed other classifiers for all the data sets, especially for Set 3 with 89.27% accuracy, 89% precision and ROC of 95.3%. To validate the developed models two external data sets, AID1189 and AID1194, with mutagenicity data were tested showing 62% accuracy with 67% precision and 65% ROC area and 91% accuracy, 91% precision with 96.3% ROC area respectively. A Random Forest model was used the approved drugs from DrugBank and metabolites from the Zinc Database with True Positives rate almost 85% showing the robustness of the model. Conclusion: We have created a new mutagenicity benchmark data set with around 8,000 compounds. Our work shows that highly accurate predictive mutagenicity models can be built using machine learning methods based on chemical descriptors and trained using this set, and these models provide a complement to toxicophores based methods. Further, our work supports other recent literature in showing that Random Forest models generally outperform other comparable machine learning methods for this kind of application. © 2012 Seal et al.
Veena T.,Malabar Christian College |
Ranjith A.P.,University of Calicut |
Santhosh S.,Malabar Christian College |
Kishore L.,Malabar Christian College
Zootaxa | Year: 2014
The rarely collected Oriental genus Neoclarkinella Rema and Narendran, 1996 is reviewed. Four species, all from India, are recognized of which two are described as new, namely Neoclarkinella janakikkadensis sp. nov., and N.narendrani sp. nov. from Kerala, India. A key to the oriental species of the genus is provided along with a character state matrix. Copyright © 2014 Magnolia Press.
Jaleel U.C.A.,Malabar Christian College |
Rakhila M.,Malabar Christian College |
Parameswaran G.,University of Calicut
Advances in Physical Chemistry | Year: 2010
Computational tools, specifically molecular mechanical force field (MM+) and semiempirical (PM3) and density functional methods (DFT) are applied to sets of schiff bases and their complexes. The results are compared with experimental data. It is also found that the simulated IR spectra are in consistence with the experimental data. Copyright © 2010 U. C. Abdul Jaleel et al.