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Neog K.,Central Muga Eri Research and Training Institute CMER and TI | Ranjit Singh H.,North East Institute of Science and Technology NEIST | Unni B.,North East Institute of Science and Technology NEIST | Sahu A.K.,Regional Muga Research Station RMRS
African Journal of Biotechnology | Year: 2010

Eleven populations of muga silkworm, Antheraea assamensis Helfer, the golden silk yarn producer of northeast India, was subjected to RAPD marker analysis in order to assess its genetic diversity. The genomic DNA extracted from muga silkworms were analysed using 50 random primers among which 36 polymorphic primers generated 309 bands. RAPD profile of the isolated DNA revealed a high level of genetic polymorphism. The average amplicons per primer was found to be 8.58, and 94.82% amplicons were polymorphic. Cluster analysis based on Jaccard's similarity coefficients resulted in the formation of two main clusters with one population on one cluster and the remaining on the other cluster. Jaccard's similarity coefficients ranged from 0.122 to 0.863 indicating a high level of genetic diversity within muga silkworm collection. The study concluded that, although there lays little morphological differences among the collected muga silkworm populations, the populations are highly polymorphic which might have enabled the silkworm to survive under a restricted geographical location, that is north east region of India only but under diverse climatic conditions for a long period. This study may be useful in identifying diverse genetic stocks of A. assamensis, which may be conserved on a priority basis. © 2010 Academic Journals. Source


Deka Bhuyan P.,North East Institute of Science and Technology NEIST | Chutia M.,North East Institute of Science and Technology NEIST | Chutia M.,Training Institute | Pathak M.G.,North East Institute of Science and Technology NEIST | Baruah P.,North East Institute of Science and Technology NEIST
JAOCS, Journal of the American Oil Chemists' Society | Year: 2010

Sheath blight and brown spot disease of rice caused by Rhizoctonia solani and Bipolaris oryzae causes significant yield loss in rice production worldwide. The present study was undertaken to examine the effect of two essential oils (EOs) from Lippia geminata and Cymbopogon jwarancusa on in vitro growth and sporulation of these two pathogens. The fungal radial growth was inhibited at very low concentration (25 ppm) of the EOs. Similarly, fungal spore production was also inhibited up to ≥80% at 500 ppm of EOs. However, fungal sporulation was completely retarded at 1,000 ppm of L. geminata EO. Very low oil concentrations (10 ppm) accelerated the radial growth (0-5 mm) and spore germination (3.5-8.5%) of the pathogens. At higher oil concentrations, the mycelial growth and spore productions were completely inhibited. The IC 50 value of the EO of C. jwarancusa was 365.45 and 336.74 ppm and for L. geminata, it was 420.16 and 481.47 ppm against B. oryzae and R. solani, respectively. GC-MS analysis of the oils showed 54.36% piperitone and 30.86% α-phellandrene as major compounds in C. jwarancusa whereas 25.9% geranial and 14.6% neral in L. geminata oil. Essential oils from Lippia geminata and Cymbopogon jwarancusa appear to be good candidates for the in vitro control of these two rice pathogens and can be successfully utilized in management strategies of pathogens in appropriate formulation. © 2010 AOCS. Source


Khare P.,North East Institute of Science and Technology NEIST | Baruah B.P.,North East Institute of Science and Technology NEIST
Energy Sources, Part A: Recovery, Utilization and Environmental Effects | Year: 2014

In the present investigation, pyrolytic behavior of perhydrous Indian coals was evaluated using thermogravimetric analysis from 50 to 1,000°C. The devolatilization was classified into five major regions of thermal activity, i.e., dehydration of water, pre-plastic region, plastic range, secondary devolatilization, and contraction region. The values of activation energies in different regions indicate to follow different mechanisms during pyrolysis. Up to 850°C, different mechanisms, i.e., dehydration, desorption, devolatilization, and thermal degradation (tar and hydrocarbon formation), are the controlling steps. From 850°C, consecutive reactions like dehydrogenation, condensation, and contraction of carbon planes take place. These coals are of sub-bituminous rank; however, their activation energies for various regions are found to lie within the ranges reported for bituminous coals, which is due to their perhydrous nature. © Taylor & Francis. Source


Mishra M.,North East Institute of Science and Technology NEIST | Das M.R.,North East Institute of Science and Technology NEIST | Goswamee R.L.,North East Institute of Science and Technology NEIST
Journal of Sol-Gel Science and Technology | Year: 2010

Silica supported Nickel Oxide fine particles have been synthesized through sol-gel derived Ni-Al Layered Double Hydroxide (LDH) and coated over honeycomb ceramic pre-forms through dip-coating technique. The powder products of supported materials have low crystallinity, negative zeta potential, exhibit high dispersibility and suitable for further processing by coating techniques. The powder X-ray diffraction (XRD) patterns have shown that there is an increase of basal spacing by 3.02 Å in acetylacetonate intercalated LDH. The particles of <2 μm size increase with the rise of LDH component in the composite. The particles of NiO structure formed on decomposition of composites have crystallite size <20 nm. Due to the interlayer reduction of NiO crystallites, the unsupported LDH on calcination gives Ni0 particles of size around 4.18 nm. The Scanning Electron Microscopy (SEM) patterns of coated supported suspensions over ceramic substrates show formation of thin, crack free coats with uniform distribution of particles. © 2010 Springer Science+Business Media, LLC. Source

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