Guwāhāti, India
Guwāhāti, India

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Hoque S.,IASST | Dass N.,IASST | Sarma N.S.,IASST
Journal of Polymer Materials | Year: 2011

The polymerization of mesogenic monomer cholesterylacrylate (CHA) and its copolymer with 1-hexene by free radical mechanism using AIBN at 70°C are reported here. The mesogenic monomer CHA is prepared by esterification of acryloyl chloride with cholesterol. Several co-polymers of CHA and 1-hexene (PCHAH) are prepared using different feed ratios of monomer. The liquid crystalline phases are detected under hot stage microscope and the reactivity ratios of monomers CHA and 1-hexene are found as 1.8 and 1.3 respectively. The number average molecular weight (M̄Jof polymer PCHA is found as 5822 Daltons by GPC The polymers are characterized by IR, 1H-NMR spectra and thermal analysis. The Tg of PCHA is found as 90°C. © MD Publications Pvt. Ltd.


Siddique K.,Gauhati University | Nath B.K.,IASST | Karmakar S.,Gauhati University
International Journal of Nanoscience | Year: 2013

We report the synthesis of copper oxide (CuO) nanoparticles prepared by wet chemical precipitation method. The structural and dielectric properties are studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and complex impedance spectroscopy as a function of frequencies from 40 KHz to 100 KHz in the range of temperatures (308-393K). Maximum value of dielectric constants are found to be in the order of 106 which increases with increase in temperatures. From XRD data it is found that the particle size increases with increase in calcination temperatures. SEM with energy dispersive X-ray fluorescence spectrometer (EDX) results show that only CuO is present in the prepared sample. The selected area electron diffraction (SAED) pattern by TEM shows that uniform size distributions of CuO nanoparticles are present in the sample. © 2013 World Scientific Publishing Company.


Das G.C.,IASST | Deka R.,Gauhati University | Bora M.P.,Gauhati University
Physics of Plasmas | Year: 2016

In this work, we have considered the formation of warm plasma sheath in the vicinity of a wall in a plasma with considerable presence of dust particles. As an example, we have used the parameters relevant in case of plasma sheath formed around surfaces of various solid bodies in space, though the results obtained in this work can be applied to any other physical situation such as laboratory plasma. In the ion-acoustic time scale, we neglect the dust dynamics. The dust particles affect the sheath dynamics by affecting the Poisson equation which determines the plasma potential in the sheath region. It is important to note that our calculations are valid only when the amount of dust particles is not sufficient so as to affect the plasma dynamics in the dust-acoustic time scale, but enough to affect the plasma sheath. We have assumed the current to a dust particle to be balanced throughout the analysis. This makes the grain potential dependent on plasma potential, which is then incorporated into the Poisson equation. The resultant numerical model becomes an initial value problem, which is described by a 1-D integro-differential equation, which is then solved self-consistently by incorporating the change in plasma potential caused by inclusion of the dust potential in the Poisson equation. © 2016 Author(s).


Boruah D.C.,IASST | Devi R.,IASST | Tamuli S.,Veterinary College | Kotoky J.,IASST | Sharma D.K.,Gauhati University
Journal of Food Science and Technology | Year: 2012

This study evaluated the hypolipidemic effect of crude polyphenol fraction from Clerodenrdon colebrookianum (CPCC) leaves in cholesterol fed rats. Crude polyphenol fraction was obtained from the ethyl acetate extract of Clerodenrdon colebrookianum (CC). Investigation was conducted by administering graded oral doses (0.25 g, 0.5 g and 1 g/kg b. w. /day) of the CPCC for a period of 28 days. Significant (p < 0.01) rise in plasma total cholesterol (TC), triglycerides (TG), phospholipids (PL), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C) and decrease in high-density lipoprotein cholesterol (HDL-C) were observed in cholesterol fed rats. Increased lipid profile has been depleted and high-density lipoprotein cholesterol (HDL-C) has been increased after chronic feeding of CPCC. In addition, CPCC extract enhanced the excretion of fecal cholesterol (FC) but could not arrest the 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase activities. Histopathological observations showed loss of normal liver architecture in cholesterol fed rats which were retained in CPCC treated groups. Moreover, the analysis of CC extract demonstrated the presence of substantial amount of total polyphenols, flavonoids and tannins content, further HPLC analysis led to the identification and quantification of two most important biologically active secondary metabolites i.e. (+) Catechin (432 ppm) and Quarcetin (105 ppm). The findings of this study suggested that CPCC had a strong hypolipidemic function and could be used as a supplement in healthcare foods and drugs. © 2012, Association of Food Scientists & Technologists (India).


Talukdar A.K.,Gauhati University | Deka S.,IASST | Hussain A.,Dudhnoi College
Nature Environment and Pollution Technology | Year: 2010

The water quality index (WQI) of Goalpara town and its surrounding areas in Assam was studied and evaluation made for suitability of water for drinking purposes. Twenty groundwater samples from tube wells and open wells were collected during the period from November, 2007 to March, 2008 and chemically analyzed. It was found that WQI . of tube well is 5.5% excellent, 60% good, 14% poor and 20% very poor for drinking purpose, while for open wells it was 38% good, 31% poor and 31% very poor. Comparatively tube wells water is better than the open wells water, it was found that excessive application of fertilizers, pesticides and irregular uses are mostly responsible for degrading water quality, and to mitigate it proper treatment and measures have to betaken.


PubMed | Veterinary College, Gauhati University and IASST
Type: Journal Article | Journal: Journal of food science and technology | Year: 2015

This study evaluated the hypolipidemic effect of crude polyphenol fraction from Clerodenrdon colebrookianum (CPCC) leaves in cholesterol fed rats. Crude polyphenol fraction was obtained from the ethyl acetate extract of Clerodenrdon colebrookianum (CC). Investigation was conducted by administering graded oral doses (0.25g, 0.5g and 1g/kg b. w. /day) of the CPCC for a period of 28days. Significant (p<0.01) rise in plasma total cholesterol (TC), triglycerides (TG), phospholipids (PL), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C) and decrease in high-density lipoprotein cholesterol (HDL-C) were observed in cholesterol fed rats. Increased lipid profile has been depleted and high-density lipoprotein cholesterol (HDL-C) has been increased after chronic feeding of CPCC. In addition, CPCC extract enhanced the excretion of fecal cholesterol (FC) but could not arrest the 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase activities. Histopathological observations showed loss of normal liver architecture in cholesterol fed rats which were retained in CPCC treated groups. Moreover, the analysis of CC extract demonstrated the presence of substantial amount of total polyphenols, flavonoids and tannins content, further HPLC analysis led to the identification and quantification of two most important biologically active secondary metabolites i.e. (+) Catechin (432ppm) and Quarcetin (105ppm). The findings of this study suggested that CPCC had a strong hypolipidemic function and could be used as a supplement in healthcare foods and drugs.

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