Imphal, India
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Agrawal H.,Banasthali University | Singh L.I.,Imphal College | Saraswat P.K.,P.A. College | Saraswat V.K.,Banasthali University
AIP Conference Proceedings | Year: 2013

In the present paper, I-V characteristics and DC volume conductivity of Se-In-Sb semi-conducting glasses has been discussed. This is an effort towards the understanding of physics of temperature dependence of dc electrical volume conductivity of Se90In10-xSbx(X=2,4,6&8) glass in bulk form. These Chalcogenide glasses were prepared by melt quenching (rapid cooling of melt) technique. The amorphous nature of as prepared glass was confirmed by XRD. Using Keithley Electrometer / High resistance Meter 6517 A, the I-V characteristics of these glasses have been recorded in a temperature range from room to 100°C and the voltage range was taken from 10V to 150V for elevated temperatures. Variation in conductivity, derived from I-V curves, as a function of composition of samples is explained on the basis of bonds formed in the system. Additionally, the Poole-Frenkel conduction mechanism has also been verified. © 2013 AIP Publishing LLC.

Lahiri S.,Saha Institute of Nuclear Physics | Takao T.,Osaka University | Devi P.G.,Saha Institute of Nuclear Physics | Devi P.G.,Imphal College | And 6 more authors.
BioMetals | Year: 2012

Here we have examined the association of an aureolic acid antibiotic, chromomycin A3 (CHR), with Cu 2+. CHR forms a high affinity 2:1 (CHR:Cu 2+) complex with dissociation constant of 0.08 × 10 -10 M 2 at 25°C, pH 8.0. The affinity of CHR for Cu 2+ is higher than those for Mg 2+ and Zn 2+ reported earlier from our laboratory. CHR binds preferentially to Cu 2+ in presence of equimolar amount of Zn 2+. Complex formation between CHR and Cu 2+ is an entropy driven endothermic process. Difference between calorimetric and van't Hoff enthalpies indicate the presence of multiple equilibria, supported from biphasic nature of the kinetics of association. Circular dichroism spectroscopy show that [(CHR) 2:Cu 2+] complex assumes a structure different from either of the Mg 2+ and Zn 2+ complex reported earlier. Both [(CHR) 2:Mg 2+] and [(CHR) 2:Zn 2+] complexes are known to bind DNA. In contrast, [(CHR) 2:Cu 2+] complex does not interact with double helical DNA, verified by means of Isothermal Titration Calorimetry of its association with calf thymus DNA and the double stranded decamer (5′-CCGGCGCCGG-3′). In order to interact with double helical DNA, the (antibiotic) 2 : metal (Mg 2+ and Zn 2+) complexes require a isohelical conformation. Nuclear Magnetic Resonance spectroscopy shows that the Cu 2+ complex adopts a distorted octahedral structure, which cannot assume the required conformation to bind to the DNA. This report demonstrates the negative effect of a bivalent metal upon the DNA binding property of CHR, which otherwise binds to DNA in presence of metals like Mg 2+ and Zn 2+. The results also indicate that CHR has a potential for chelation therapy in Cu 2+ accumulation diseases. However cytotoxicity of the antibiotic might restrict the use. © Springer Science+Business Media, LLC. 2011.

Singh M.A.,Manipur University | Singh M.A.,Imphal College | Chandrasekaran S.,Manipur University | Chandrasekaran S.,Tamil Nadu Agricultural University | And 6 more authors.
Asian Journal of Chemistry | Year: 2010

Twenty samples of brinjals (1 kg each) are collected from different vegetable markets of Imphal, India at fortnightly interval to assess the extent of pesticide residues. The samples were analyzed using multiresidues methodology (MRM) and residues were estimated by GLC for the presence of organochlorine, organophosphorus and synthetic pyrethroid insecticides. The study reveals that the maximum residue levels was observed for phorate, dimethoate, chloropyriphos, triazophos, β-endosulfan, λ-cyhalothrin and cypermethrin were 0.01, 0.19, 0.12, 0.23, 0.08, 0.12 and 0.13, respectively. None of the samples exceeded their respective maximum residues limit.

Bhaigyabati T.,Institutional Biotech Hub | Devi P.G.,Imphal College | Bag G.C.,Imphal College
Research Journal of Pharmaceutical, Biological and Chemical Sciences | Year: 2014

Hedychium species is one of the important aromatic, ornamental medicinal plants of North east India. In the present study, total flavonoid content and antioxidant activity of aqueous rhizome extract of three Hedychium species namely H. rubrum, H. coronarium and H. spicatum were investigated. In antioxidant activity: free radical scavenging activity, reducing power and total antioxidant activity were determined and expressed in terms of standard used for the respective assay. Total flavonoid content of aqueous rhizome extract of H. rubrum, H. coronarium and H. spicatum in terms of quercetin equivalent (QE) was 3.22, 2.77 and 0.74 μg/100g of extract respectively. In DPPH assay H. rubrum (32.3%) showed the highest free radical scavenging activity followed by H. coronarium (21%) and lowest activity in H. Spicatum (5.76%). In reducing power method, both standard ascorbic acid and sample extracts were found to be increased in a dose dependent manner. Total antioxidant activity of aqueous rhizome extract of H. rubrum, H. coronarium and H. spicatum in terms of ascorbic acid equivalent (AAE) was 207.3, 157.5 and 102.6 μg/ml of extract. The present data indicates that aqueous rhizome extract of all the three Hedychium species are potential source of antioxidant which may be due to the presence of flavonoid in the extracts. Among the three Hedychium species, H. rubrum was found to have the highest total flavonoid content and antioxidant activity.

Hemanta Singh R.K.,Imphal College | Mohon Singh K.H.,Imphal College
International Journal of Earth Sciences and Engineering | Year: 2011

The rock exposures in the Tengnoupal-Sita road section comprise mainly of weak rock of Disang and Barail Groups characterized by shale with frequent intercalation of fine sandstone and siltstone beds, which is a prominent feature in the turbidite dominated flysch sediments of Tertiary in the state of Manipur. Besides, the rock mass is highly fractured and jointed because of intense folding and faulting associated with the India and Burma plate collision tectonics. Therefore, the rocks are highly weathered to such a degree that most of the rocks exposed all along the section may be treated as scientifically soil from engineering point of view. This weak nature of the rock in conjunction with the moderate to steep slope, thick mantle of waste and heavy rainfall, improper drainage, nonsystematic and excessive landuse render the rocks very vulnerable to instability and masswasting processes. The landslide study along the Tengnoupal-Sita road study has been based on the kinematic analysis of fractures and slope mass rating (SMR). From the study, it has been observed that planar failure is the common type of slope failure accompanied by both wedge and central failures. The plasticity index of all the soil samples is found to exceed the plastic limits of the soils when low to moderate rainfall occur. The slopes as deduced from SMR indicate instability and belong to class VIB-VIA. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.

Lonibala R.K.,Manipur University | Devi T.H.P.,Manipur University | Yumnam S.,Manipur University | Devi R.K.B.,Manipur University | Devi R.K.B.,Imphal College
Asian Journal of Chemistry | Year: 2010

Some bivalent transition metal complexes of 3-hydroxypicolinamide (LH) of the empirical formulae, [M(LH) 2Cl(H 2O)]Cl [M = Mn, Co, Ni, Cd], [Cu(LH) 2Cl(OH)], [Hg(LH) 2Cl 2] and [M(L) 2(H 2O)n] [M = Mn, Co, Ni, Cu, Cd, Hg] have been synthesized. 1H NMR studies suggested the presence of one dissociable proton in the ligand. IR and NMR data show that LH acts as a neutral N,O chelating ligand in the protonated form while it behaves as a uninegative O, O chelating species in the monodeprotonated form. Electronic spectral studies suggest distorted octahedral geometry for Mn(II), Co(II), Ni(II) and Cu(II) complexes. Isotropic nature of Mn(II) complexes and anisotropic nature of Cu(II) complexes at LNT have been inferred from the ESR studies. Appreciable covalent nature of bonding in the complexes is suggested by the bonding parameters obtained from electronic and ESR spectra. 113Cd chemical shift also shows that Cd(II) ion is covalently bonded in [Cd(LH) 2Cl(H 2O)]Cl. XRD powder patterns of the Cu(II) complexes are indexed for a tetragonal crystal system for [Cu(LH) 2Cl(OH)] and orthorhombic for [Cu(L) 2(H 2O) 2]. Tentative structures of these complexes have been suggested based on their elemental, thermal, molar conductance, magnetic moment, and spectral data.

Chandra Singh M.,Imphal College | Kushwaha R.A.S.,Manipur University | Srivastava G.,University of Lucknow | Mehrotra R.C.,University of Lucknow
Journal of the Geological Society of India | Year: 2012

Some plant remains are described from the Laisong Formation (Barail Group) of Thoubal and Senapati districts of Manipur. The flora is diverse comprising gymnospermous, monocotyledonous and dicotyledonous forms and indicates tropical to subtropical climate in the vicinity of the area during the deposition of the host rocks.

Singh M.C.,Imphal College | Kundal P.,Rashtrasant Tukadoji Maharaj Nagpur University | Kushwaha R.A.S.,Manipur University
Journal of the Geological Society of India | Year: 2010

Oligocene-Miocene deposits of Bhuban and Boka Bil Formations, Surma Group, Manipur Western Hill consist of well preserved ichnofossil assemblages. These formations are represented by eight lithofacies such as Massive sandstone (Sm), Rippled marked argillaceous sandstone (Sr), Wavy laminated sandstone-siltstone- silty shale (Sw), Laminated shale (Fl), Massive mudstone (Fm), Trough cross-bedded sandstone (St), Lenticular laminated sandstonesiltstonesilty shale (Sll) and Laminated to massive sandstone-siltstone (Ssc). Fifteen ichnospecies were identified, which further categories into Skolithos, Cruziana, and Skolithos/Cruziana ichnofacies. Overall distribution pattern and behavioural nature of the ichnoassemblage and sedimentological attributes suggests that the sediments of Bhuban and Boka Bil Formations were deposited under frequent fluctuating sea level, moderate to strong energy condition, subtidal to lower intertidal environment, rich in organic nutrients. © 2010 Geological Society of India.

Singh S.J.,Manipur University | Singh L.R.,Manipur University | Devi S.K.,Manipur University | Singh S.S.,Manipur University | And 2 more authors.
Protein and Peptide Letters | Year: 2015

A new thermostable caseinolytic serine protease was purified from the latex of Euphorbia heterophylla L. to electrophoretic homogeneity by a procedure involving successive steps of pretreatment of the latex, PEG fractionation, CM-cellulose chromatography and DEAE-cellulose chromatography. The purified protease was found to be a monomeric protein of molecular weight 77.2 kDa. It exhibited caseinolytic activity with hyperbolic azocasein saturation with Vmax and Km values of 0.11 units.mL-1 and 0.55 mg.mL-1 respectively. Specific inhibitory studies revealed the enzyme to be a serine protease. The protease was characterized by pH optimum of 8.0 and high thermostability with T1/2 of 75°C. Based on the results of peptide mass fingerprinting analysis, the protease was shown to be a new protein not characterized earlier. © 2015 Bentham Science Publishers.

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