Ernakulam, India
Ernakulam, India

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Suma K.K.,Cochin University of Science and Technology | Suma K.K.,Maharajas College | Jacob S.,Cochin University of Science and Technology | Joseph R.,Cochin University of Science and Technology
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2010

Vinyl acetate-butyl acrylate (VAc-BuA) copolymer latex was prepared by emulsion polymerization. The polymerization conditions and the composition were optimized. The 85/15 wt.% (vinyl acetate/butyl acrylate) gave good tensile strength of the order of 15.6 MPa and a glass transition temperature (Tg) value of -6.49 °C. This copolymer was used as a binder in the paint formulation. In this formulation nanosized TiO2 sol was used as a pigment instead of conventional rutile TiO2. Nanosized TiO2 is prepared by wet process. These nanosized TiO2 rutile colloidal sol has improved properties such as photostability, UV shielding, dispersion stability, etc. The surface properties of paint were found to be superior compared to commercially used paint. © 2009 Elsevier B.V. All rights reserved.


Jacob B.P.,Kmm Government Womens College | Thankachan S.,Maharajas College | Xavier S.,Maharajas College | Mohammed E.M.,Maharajas College
Journal of Alloys and Compounds | Year: 2013

A series of NiTbxFe2-xO4 (x = 0.0, 0.1, 0.2, 0.3) nanoparticles with small size have been prepared using sol-gel technique. The effect of Tb3+ substitution on the crystalline phase, crystallite size and magnetic, electrical and dielectric properties has been investigated in detail. The lattice constant shows an increasing trend with increase in Tb3+ ion concentration. The high frequency tetrahedral vibration band m1 and the low frequency octahedral vibration band m2 in the FTIR spectra are in the reported range. The observed shift in m2 towards lower wave number side with increase in terbium concentration suggests the occupation of Tb3+ ions predominantly on octahedral sites. Saturation magnetization is found to decrease with terbium addition. Magnetic hysteresis loss is observed to decrease up to x = 0.2 and then increases. The room temperature resistivity values are found to increase with terbium content. The observed dielectric dispersion with frequency is explained on the basis of Maxwell-Wagner two-layer model and electron hopping mechanism which is responsible for conduction and polarization. Dielectric constant and dielectric loss are found to decrease by terbium addition and is explained in terms of the decrease in hopping rate due to the substitution of Fe3+ ions by Tb3+ ions on the octahedral sites. The increased resistivity and reduced dielectric loss attained in terbium doped ferrite is promising as it is desirable for high frequency applications. © 2013 Elsevier B.V. All rights reserved.


Suresh V.,Government Victoria College | Krishnakumar K.A.,Maharajas College | Asha V.V.,Rajiv Gandhi Center for Biotechnology
Biomedicine and Pharmacotherapy | Year: 2015

The existing screening systems for anti-hepatitis B virus (anti-HBV) drug discovery is time-consuming mainly due to the laborious detection system it is using. A new fluorescence based screening system for high throughput anti-HBV drug discovery was created by tagging hepatitis B surface antigen (HBsAg) with monomeric red fluorescent protein and hepatitis B virus (HBV) core protein with enhanced green fluorescent protein. The two constructs were co-transfected on to Hep3B cells and the transfection was stabilized by fluorescent activated cell sorter (FACS). The fusion proteins expressed through the secretory protein pathway as evidenced by localization with ER-Tracker and tubulin tracker. The new system has given analogues results like that of conventional enzyme-linked immunosorbent assay (ELISA). Hence it can be of very high potential for large scale drug screening systems. © 2015 Elsevier Masson SAS.


Jacob B.P.,Maharajas College | Thankachan S.,Maharajas College | Xavier S.,Maharajas College | Mohammed E.M.,Maharajas College
Physica Scripta | Year: 2011

A series of nickel-cadmium ferrite, Ni0.9Cd0.1Gd xFe2-xO4 (x=0, 0.1, 0.2 and 0.3), was prepared through the sol-gel technique. Samples were characterized using x-ray diffraction (XRD), Fourier transform infrared spectroscopy, a wavelength dispersive x-ray fluorescence spectrometer, a transmission electron microscope and a vibrating sample magnetometer. XRD analysis confirmed the formation of single-phase spinel structure in all the samples. The effect of Gd3+ doping on the crystalline phase, crystallite size and magnetic properties was investigated in detail. Gadolinium doping improved the crystallinity and induced compressive strain in Ni-Cd mixed ferrite. The lattice parameter was observed to increase for minor Gd3+ doping (up to x=0.1); however, further doping resulted in a reduction of the lattice constant. The saturation magnetization decreased and coercivity increased with an increase in gadolinium content. © 2011 The Royal Swedish Academy of Sciences.


Thankachan S.,Maharajas College | Jacob B.P.,Maharajas College | Xavier S.,Maharajas College | Mohammed E.M.,Maharajas College
Journal of Magnetism and Magnetic Materials | Year: 2013

Samarium doped magnesium ferrite was prepared (MgSmxFe 2-xO4) by sol-gel method. X-ray diffraction analysis reveals that the samples are single phasic with crystallite sizes in the 13-25 nm regime. Increase in lattice parameter with doping concentration suggests the expansion in unit cell with Sm3+ doping. Fourier Transform Infrared Spectrum shows substitution of Sm3+ ions in octahedral B site. Transmission Electron Micrograph shows the spherical shape of nano-particles. Magnetic measurement shows a decrease in magnetization with doping which is explained using dependence on particle size. © 2013 Elsevier B.V.


Jacob B.P.,Maharajas College | Thankachan S.,Maharajas College | Xavier S.,Maharajas College | Mohammed E.M.,Maharajas College
Journal of Alloys and Compounds | Year: 2012

Terbium doped Ni-Zn ferrite, Ni 0.4Zn 0.6Tb xFe 2-xO 4 (x = 0, 0.05, 0.1, 0.15 and 0.2) have been prepared through sol-gel technique. Formation of single phase FCC spinel structure is identified in all the compositions using X-ray diffraction technique. The effect of Tb 3+ doping on the crystalline phase, crystallite size, dielectric properties and AC conductivity has been investigated in detail. Lattice constant is observed to increase with terbium content; but beyond certain concentration of terbium (x > 0.15), it decreased. DC resistivity measurements were carried out in the temperature range 300-523 K. All the compositions exhibited usual semiconducting nature of ferrites and the resistivity of the samples found to increase with terbium content up to x = 0.15. The metallic behavior of the doped samples observed in the lower temperature region is explained in terms of elastic and inelastic scattering due to the rare earth ions. The investigations on dielectric constant, dielectric loss and AC conductivity was carried out in the frequency range 100 Hz-20 MHz from room temperature to 563 K. Frequency dependence of dielectric constant showed normal behavior and is in good agreement with Koop's phenomenological theory of dielectric dispersion. AC conductivity measurements suggested conduction due to small polaron hopping. AC conductivity as well as dielectric constant is found to increase with temperature and which is due to thermally enhanced drift mobility of charge carriers. The observed decrease in dielectric loss with terbium content up to x = 0.15 is explained in terms of increase in resistivity. © 2012 Published by Elsevier B.V.


Thankachan S.,Maharajas College | Xavier S.,Maharajas College | Jacob B.,Maharajas College | Mohammed E.M.,Maharajas College
Journal of Experimental Nanoscience | Year: 2013

Nano-sized magnesium ferrite was synthesised using co-precipitation and sol-gel techniques. Structural characterisation was performed using X-ray diffractometer (XRD), Fourier transform infrared (FTIR) spectrometer and scanning electron microscope. XRD analysis reveals the prepared samples are single phasic without any impurity. Particle size calculation shows that the crystallite size of sol-gel prepared samples is 9 nm and co-precipitation sample is 11 nm. FTIR analysis confirmed spinel structure of the prepared samples. Magnetic measurements show that both the samples are ferromagnetic with a high degree of isotropy in co-precipitation derived sample. The frequency dependence of the dielectric constant in the range 100 Hz-20 MHz was also investigated in the temperature range 303-533 K. The results of both the samples followed Maxwell-Wagner model based on interfacial polarisation in consonance with Koops theory. © 2013 Copyright Taylor and Francis Group, LLC.


Varghese S.,Maharajas College | Muraleedharan Nair M.K.,Maharajas College
Research Journal of Pharmaceutical, Biological and Chemical Sciences | Year: 2010

The Schiff base 2-hydroxybenzilidene-3-aminophenol was synthesized and used for the preparation of coordination complexes with some transition and inner transition metals. All the compounds were characterized by elemental analysis, IR and UV spectral studies, and molar conductivity studies. The antimicrobial activities were checked against four different bacterial species E.coli, B.subtills, S.auereus and P.aeruginosa and also screened for activity against the fungus Rhizopus, the common bread mould.


Ajitha P.S.,Maharajas College | Muraleedharan Nair M.K.,Maharajas College
Research Journal of Pharmaceutical, Biological and Chemical Sciences | Year: 2010

Schiff base complexes of rare earth metals have been an interesting research field for the past few years due to their pharmacological, clinical, analytical and biological applications. Also the chemistry of antipyrine and its derivatives has been extensively investigated due to its physiological properties. The study of the metal complexes of antipyrine in antineoplastic medication, molecular biology and bioengineering has become hotspots in recent years. We report a new Schiff base formed from pyridoxal, a vitamin and 4-aminoantipyrine. Here we explore the antibacterial activity of the newly synthesized Schiff base formed from 4-aminoantipyrine with vitamin B. This Schiff base acts as a tridentate ligand, which form very stable complexes with the lanthanide metals La, Ce, Pr, Nd, Sm, Gd, Tb, Dy and Er. The structure of the ligand and complexes were characterized by elemental analysis, IR and UV spectral studies, magnetic susceptibility measurements, electrical conductance and thermo gravimetric analysis. The ligand is found to be chelating with the metal ion in a neutral tridentate manner through the carbonyl oxygen, azomethine nitrogen and the phenolic oxygen. The nitrate ions are monodentately coordinated to the metal ion. All complexes are found to have the formula, [ML2 (NO3)3]. All the studies reveal a coordination number of nine for the metals in all the complexes.


Vijayakumari K.N.,Maharajas College | Murali D.,Sree Narayana College
Indian Journal of Fisheries | Year: 2012

Peripheral haematological parameters such as total erythrocyte, leucocyte and thrombocyte counts (TEC, TLC, TTC), haemoglobin content (Hb), haematocrit (Ht), erythrocyte sedimentation rate (ESR), RBC/WBC ratio, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) of Puntius filamentosus in relation to sex, maturity stages, standard length of the fish and seasons were analysed. The results of the present study shows that peripheral haematological make-up is not much affected by the sex of the fish. However, most of the haematological parameters (TEC, TLC, TTC, Hb and Ht) registered higher mean values in males than in females. Gonad maturity has only little influence on the peripheral haematological make-up. But there was a general tendency for decrease in the mean values of TEC, TTC, Hb and Ht in fish at maturity stage IV. Simple linear correlation analysis (r) revealed that TTC (p<0.01), Hb and MCH (p<0.05) had significant negative association and Ht (p<0.05) showed significant positive association with standard length (SL). Majority of haematological variables (TEC, TLC, TTC, Hb , Ht, MCH and MCHC) recorded higher mean values during pre-monsoon (February- May) than during monsoon (June- September) and postmonsoon (October- January) seasons.

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