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Search Results: 1 - 10 of 221478 matches for " Narayan C. Mandal "
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Use of Bacteriocin Producing Lactococcus lactis subsp. lactis LABW4 to Prevent Listeria monocytogenes Induced Spoilage of Meat  [PDF]
Soma Barman, Ranjan Ghosh, Narayan C. Mandal
Food and Nutrition Sciences (FNS) , 2014, DOI: 10.4236/fns.2014.522224
Abstract: A bacteriocin producing strain of Lactococcus lactis subsp. lactis LABW4 was isolated from naturally fermented milk product which exhibited strong antibacterial activity against Listeria monocytogenes MTCC657, a food spoilage psychrophilic organism. Both cell free and heat killed supernatants of LABW4 were effective to produce zones of inhibition against L. monocytogenes in vitro. The antibacterial metabolite(s) of LABW4 showed strong cidal effect on the growth of L. monocytogenes. Meat samples, mixed with heat killed supernatant of LABW4 when inoculated with Listeria, remain fresh up to 25 days in refrigerated condition whereas spoilage started immediately after 24 hours of inoculation for control sets. Enhancement of Lactate dehydrogenase of L. monocytogenes upon treatment with LABW4 cell free supernatant suggested its lytic mode of action. Cell lysis or degradations were also supported by scanning electron micrograph of treated cells.
Restoration in soil and plant properties in landslide damaged forest ecosystem
Tej Narayan Mandal
Nepalese Journal of Biosciences , 2012, DOI: 10.3126/njbs.v2i0.7488
Abstract: The pattern of natural restoration in soil and plant components was studied in five landslide-damaged (1-58-year-old) sites in the tropical moist sal ( Shorea robusta) forest ecosystem of Nepal Himalaya .Rate of restoration in soil properties was faster in the early successional stages (1-15 year) than late stages while plant biomass recovered rapidly after 15-year age. Based on the recovery in ecosystem properties; the 58- year-old landslide damaged site demonstrated the re-establishment of an ecosystem showing closer affinity with the mature sal forest. On the basis of best fit power function models it was concluded that the estimated times for the 58-year old site to reach the level of undisturbed matured sal forest would be about 30-35 years for microbial biomass (C and N) and plant biomass and about 100-150 year for soil organic Carbon and total N. Higher accumulation of soil microbial biomass, plant biomass and high N-mineralization rate at late successional stages indicated the re-establishment of an ecosystem with enriched soil and restitution of nutrient cycling during the course of ecosystem restoration DOI: http://dx.doi.org/10.3126/njbs.v2i0.7488 Nepalese Journal of Biosciences 2 : 40-45 (2012)
Seasonal variations in available N and N-mineralization in relation to fine roots in landslide damaged sites in the sal forest ecosystem of Nepal Himalaya
Tej Narayan Mandal
Nepalese Journal of Biosciences , 2011, DOI: 10.3126/njbs.v1i0.7478
Abstract: Seasonal dynamics of available nitrogen and N-mineralization in relation to fine root biomass was studied in five landslide damaged (1 to 58 years old) sites in the moist tropical sal ( Shorea robusta ) forest ecosystem of Nepal Himalaya. Comparisons were made with an undisturbed mature sal forest site located in the same region. Concentrations of soil available-N (NH 4 + and NO 3 - ) increased with the age of site till 40-year old sites and then declined. However, the proportion of NH 4 + in total available N increased distinctly with increase in the age of sites. The NH 4 + : NO 3 - ratio increased considerably from 1.15 in 1-year site to 2.4 in mature sal forest. On the other hand, the net N-mineralization rate increased consistently until 58 years of age but the proportion of nitrification rate relative to ammonification rate distinctly decreased beyond 40 years indicating the dominance of ammonification over nitrification in the older sites. Fine root biomass and N- mineralization rate both increased but available-N decreased during rainy season. On the other hand fine root biomass and N-mineralization rate both decreased and available N increased during summer season. During the summer season, fine root biomass decreased by 57 - 68% indicating a rapid turnover. High turnover of fine root at the younger sites (1 to 15 yrs old) add more organic matter for the developing vegetation. Fine root biomass was positively correlated with the concentration of available-N and N-mineralization rate. It is concluded that fine root development was facilitated by higher amounts of available-N. DOI: http://dx.doi.org/10.3126/njbs.v1i0.7478 Nepalese Journal of Biosciences 1: 114-124 (2011)
Effect of Leaf Litter Treatment on Soil Microbial Biomass  [PDF]
Pramod Sen Oli, Tej Narayan Mandal, Usha Adhikari
Open Journal of Soil Science (OJSS) , 2018, DOI: 10.4236/ojss.2018.88014
Abstract: Soil microbial biomass is an active fraction of soil organic matter. It shows quicker response than soil organic matter to any change in the soil environment. Being an index of soil fertility, it plays a key role in the decomposition of litters and fast release of available nutrients. Leaf litters of leguminous and non-leguminous species in alone and mixed form were applied as treatments in the soil to observe the changes in the magnitude of soil microbial biomass. Soil microbial biomass C and N were determined by chloroform fumigation extraction method. Increment in the concentration of microbial biomass C and N was higher in the treatments with leguminous leaf litter (497 - 571 μgCg?1, 48 - 55 μgNg?1) than the non-leguminous one (256 - 414 μgCg?1; 22 - 36 μgNg?1). However, when non-leguminous litters were mixed with leguminous litters then the values increased distinctly (350 - 465 μgCg?1, 28 - 48 μgNg?1). On the basis of increment in soil microbial biomass, leaf litters of the species considered potential to improve soil nutrients are—Cassia siamea and Dalbergia sissoo from leguminous trees, Anthocephalus + Cassia and Shorea + Dalbergia from mixed form of non-leguminous and leguminous one and Eichhornia crassipes, an alien aquatic macrophyte. The leaf litters of these species can be used as source of organic matter to improve the crop yield.
Soil microbial biomass in relation to fine root in Kiteni hill Sal forest of Ilam, eastern Nepal
Krishna Prasad Bhattarai,Tej Narayan Mandal
Nepalese Journal of Biosciences , 2012, DOI: 10.3126/njbs.v2i0.7493
Abstract: Soil microbial biomass in relation to fine root was studied in Kiteni hill Sal ( Shorea robusta ) forest of Ilam during summer season. The forest had sandy loam type of soil texture. Organic carbon was higher in 0-15 cm depth (2.09%) than in 15-30 cm depth (1.53%). Total nitrogen of 0- 15 cm depth was 0.173% and in 15-30 cm depth was 0.124%. Soil microbial biomass of carbon of Kiteni hill sal forest was (445.14 ?g g -1 ) and microbial biomass of nitrogen was (49.07 ?g g -1 ). Fine root biomass of this forest was 2.34 t ha -1 (<2 mm diameter) and 0.93 t ha -1 (2-5 mm diameter) in 0-15 cm depth and 0.73 t ha -1 (<2 mm diameter) and 0.46 t ha -1 (2-5 mm diameter) in 15-30 cm depth. Organic carbon, total nitrogen, soil microbial biomass carbon and nitrogen of upper layer soil were negatively correlated with fine root biomass of forest. DOI: http://dx.doi.org/10.3126/njbs.v2i0.7493 Nepalese Journal of Biosciences 2 : 80-87 (2012)
Effect of disturbance on fine root biomass in the Tropical moist forest of eastern Nepal
Tilak Prasad Gautam,Tej Narayan Mandal
Nepalese Journal of Biosciences , 2012, DOI: 10.3126/njbs.v2i0.7484
Abstract: Fine root biomass (<5 mm diameter) was estimated in 0-15 cm and 15- 30 cm soil depths of disturbed and undisturbed stands of tropical moist forest in eastern Nepal. The value of root mass was higher (4.28 t ha -1 ) in the undisturbed stand than the disturbed stand (2.04 t ha -1 ). The biomass of smaller fine roots (<2 mm diameter) was 1.51 and 3.2 t ha -1 in the disturbed and undisturbed stands respectively. Most of the fine roots were present in the surface soil layer (0-15 cm), in both the disturbed and undisturbed stands (67% in the disturbed and 64% in the undisturbed). The nitrogen stock in the fine roots was more (38.61 kg ha -1 ) in undisturbed stand than the disturbed stand (16.93 kg ha -1 ). More nitrogen was confined in the fine roots of <2 mm diameter in both undisturbed (28.8 kg ha -1 ) and disturbed (13.59 kg ha -1 ) stands. DOI: http://dx.doi.org/10.3126/njbs.v2i0.7484 Nepalese Journal of Biosciences 2 : 10-16 (2012)
Soil Characteristics in Moist Tropical Forest of Sunsari District, Nepal
Tilak Prasad Gautam,Tej Narayan Mandal
Nepal Journal of Science and Technology , 2013, DOI: 10.3126/njst.v14i1.8876
Abstract: The physico-chemical properties of soils of tropical moist forest (Charkoshe jungle) in Sunsari district of eastern Nepal were analyzed. The samples were collected during summer season from three depths: upper (0-15 cm), middle (15-30 cm) and deep (30-45 cm). They were analyzed for texture, pH, moisture, water holding capacity, organic carbon, total nitrogen, organic matter and microbial biomass carbon and nitrogen. The forest soil of upper and middle layers was loamy whereas that of deep layer was sandy loam. The pH value was lower (5.6) in upper layer than in the deep layer (6.6). The moisture content, water holding capacity, organic carbon, total nitrogen and organic matter were higher in upper layer and decreased with increasing depth. The higher level of soil nutrients in upper layer was due partly to reduction in the loss of top soil and partly to the increased supply of nutrients from the decomposed form of litter and fine roots of the forest plants. The average value of microbial biomass carbon in the soil was 676.6 μg g-1and microbial biomass nitrogen was 59.0 μg g-1. Nepal Journal of Science and Technology Vol. 14, No. 1 (2013) 35-40 DOI: http://dx.doi.org/10.3126/njst.v14i1.8876
1-Phenyl-3-{4-[4-(4-undecyloxybenzoyloxy)phenyloxycarbonyl]phenyl}triazene 1-oxide
Purak Das,Achintesh Narayan Biswas,Shailesh Upreti,Pradip Kumar Mandal
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808005904
Abstract: The X-ray crystallographic study of the title compound, C37H41N3O6, at 150 K establishes the N-oxide form of the triazene 1-oxide unit. There is one intramolecular N—H...O hydrogen-bonding interaction and the crystal packing is stabilized by one N—H...O, three C—H...O and three C—H...π intermolecular interactions. The dihedral angles between pairs of adjacent benzene rings are 14.9 (3), 56.3 (1) and 56.0 (1)°
Higgs Rapidity Distribution in $b {\bar b}$ Annihilation at Threshold in N$^{3}$LO QCD
Taushif Ahmed,M. K. Mandal,Narayan Rana,V. Ravindran
Physics , 2014, DOI: 10.1007/JHEP02(2015)131
Abstract: We present the rapidity distribution of the Higgs boson produced through bottom quark annihilation at third order in QCD using the threshold approximation. We provide a framework, based on the factorization properties of the QCD amplitudes along with Sudakov resummation and the renormalization group invariance, that allows one to perform the computation of the threshold corrections in a consistent, systematic and accurate way. The recent results on threshold N$^3$LO correction in QCD for the Drell-Yan production and on three loop QCD correction to Higgs form factor with bottom anti-bottom quark are used to achieve this task. We also demonstrate the numerical impact of these corrections at the LHC.
Rapidity Distributions in Drell-Yan and Higgs Productions at Threshold to Third Order in QCD
Taushif Ahmed,M. K. Mandal,Narayan Rana,V. Ravindran
Physics , 2014, DOI: 10.1103/PhysRevLett.113.212003
Abstract: We present the threshold N$^3$LO perturbative QCD corrections to the rapidity distributions of dileptons in the Drell-Yan process and Higgs boson in gluon fusion. Sudakov resummation of QCD amplitudes, renormalization group invariance, and the mass factorization theorem provide useful guidelines to obtain them in an elegant manner. We use various state of the art three loop results that have been recently available to obtain these distributions. For the Higgs boson, we demonstrate numerically the importance of these corrections at the LHC.
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