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Search Results: 1 - 10 of 22111 matches for " Badal Kumar Datta "
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Pollen Production in Relation to Ecological Class of Some Hydrophytes and Marsh Plants  [PDF]
Somnath Bhowmik, Badal Kumar Datta
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.42043
Abstract: The knowledge of quantitative production and method of dispersal give some idea about the frequency of presence of particular plant pollen grains in the atmosphere or hydrosphere. Pollen production in terms of number per anther along with the particular anther number per flower, anther length, pollen grain size, mode of anther dehiscence was determined for 51 angiospermous hydrophytes and marsh species occurring in Tripura, India. Pollen production is species specific. The level of pollen production directly related to the anther size and anther number per flower. However, no such correlation could be drawn between pollen production and size of pollen grains. Most of the hydrophytic taxa of the present investigation are anemophilous. The anemophilous taxa are characterized by high pollen production. However no correlation could be drawn from the present study between the high pollen production and mode of anther dehiscence as in all the studied taxa they show only one kind of anther dehiscence.
Aboveground Woody Biomass, Carbon Stocks Potential in Selected Tropical Forest Patches of Tripura, Northeast India  [PDF]
Koushik Majumdar, Bal Krishan Choudhary, Badal Kumar Datta
Open Journal of Ecology (OJE) , 2016, DOI: 10.4236/oje.2016.610057
Abstract: To estimate woody plant biomass stocks in different patches of forest ecosystems, total 20, 500 × 10 m (0.5 ha) sized line transects were laid in a protected area of Tripura, Northeast India. Overall, 9160 individuals were measured at ≥10 cm diameter at breast height (dbh) in 10 ha sampled area. Estimation of biomass suggested that highest coefficient for allometric relationships between density and biomass in 10 dbh classes was observed in bamboo brakes (R2 = 0.90) than lowest for semi evergreen patch (R2 = 0.48). The stock of carbon (C) was differ significantly along the forest patches (F = 7.01, df = 3.19; p < 0.01). Most of biomass stock (69.38%) was accumulated in lower dbh class (<30 cm) and only 23% of biomass was estimated at higher dbh classes (> 70 cm). Range of biomass stock (37.85 - 85.58 Mg ha-1) was low, compared to other tropical forest ecosystems in India, which implies that the proper management is required to monitor regional ecosystem C pool.
In Vitro Pollen Germination of Eichhornia crassipes (Mart.) Solms: An Insight into its Preferred Mode of Clonal Reproduction
Somnath BHOWMIK,Badal Kumar DATTA
Notulae Scientia Biologicae , 2012,
Abstract: Eichhornia crassipes (Mart.) Solms is an aquatic invasive weed throughout the tropical and subtropical regions of the world. The plant rarely produces any fruit under natural condition In order to understand the causes of failure of seed set in this plant various aspect of pollen biology were studied. Pollen fertility and pollen viability was assessed using Muntzing’ s mixture and in acetic orcein and TTZ, while pollen germination was assessed with different concentrations of sucrose supplemented with boric acid and Ca and Mg salts. The aim of present study was to find out the cause of sexual incompatibility of Eichhornia crassipes (Mart.) Solms. In spite of high pollen fertility, pollen viability and pollen germination the species show hardly any fruit set under natural condition. The abnormal pollen germination like curling of pollen tubes, shrinkage of pollen tube tips and bending of pollen tube might be reasons of sexual incompatibility of this species. It is observed that the taxa required comparatively low sucrose concentration (5%) for their optimal in vitro pollen germination (54.08%). Boric acid to certain extent also influences the in vitro pollen germination (56.2%). In the present investigation the nature of substrate in association with the effect of Boric acid, CaCO3, MgSO4 on the in vitro pollen germination of Eichhornia crassipes is also worked out. However the tested salts show no significant effect on pollen germination in the present study.
Pollen Dimorphism of Several Members of Nymphaeaceae and Nelumbonaceae: An Index of Geographical and Ecological Variation
Somnath BHOWMIK,Badal Kumar DATTA
Notulae Scientia Biologicae , 2012,
Abstract: Pollen morphology of five Nymphaea (Nymphaeaceae) species, growing in Tripura, India were analysed using Scanning Electron Microscopy. Pollen grains of Nymphaea are dimorphic (ellipsoidal and spheroidal). The exine pattern also varies among the species. The variation as reported in the present study in terms of exine pattern of the studied species suggests the feasibility of applying the data in the identification of the genus of Nymphaea. The difference in exine patterns with the earlier reports may be interpreted as reflections of genetic variations possibly due to mutational changes effected by ecological conditions. The present pollen dimorphism may be attributed by introgression of populations. The variability in pollen morphology, including size variation and morphological differences, is often associated with hybrids among angiosperm groups. The examinations of percentages of aborted grains, generally considered a good indicator of hybridity. The occurrence of monosulcate pollens in Nelumbo nucifera along with dominant tricolpate pollens may be considered as aberrant pollens because of very low percentage of occurrence of monosulcate pollens. The ecological and geographical variations in pollen morphology could be an index of the genetic impact of the environment on the plant. Thus the present difference in terms of exine pattern could be useful to separate them at varietal level.
Trends in Tree Diversity and Stand Structure during Restoration: A Case Study in Fragmented Moist Deciduous Forest Ecosystems of Northeast India
Koushik Majumdar,Uma Shankar,Badal Kumar Datta
Journal of Ecosystems , 2014, DOI: 10.1155/2014/845142
Abstract: Ecological implications for the conservation of fragmented forests to managed local plant diversity have recently drawn much attention of most conservationists. Present study investigates the importance of fragmented forests using different quantitative measures of species diversity and stand structure as indicators of natural restoration from past disturbances. Eleven independent 500?m × 10?m belt transects (5.5?ha) were established within fragmented low land moist deciduous forests of Tripura. All woody plants ≥10?cm girth at breast height (GBH) were measured. A total of 7,134 individuals with mean density of 648.55 stems ha?1 and 16.36?m2?ha?1 of basal area were recorded, which represented 134 species, 93 genera, and 43 families of woody plants. Diversity-dominance curve showed that maximum number of species were ranked >10 due to low abundance value. Maximum distributions of stems (>50%) were recorded at lowest girth class (10–30?cm) as an indication of advanced regeneration and significantly declined towards upper girth ( ; ) and height ( ; ) classes, which also indicated that some plants were adopted with ongoing disturbances through both seeded and nonseeded regeneration. Species richness ( ; ), dominance ( ; ), and density ( ; ) were significantly increased at different disturbance intensities. Disturbances strongly influenced typical community association and structure by increasing diversity and population at certain magnitude and thereby showed declining trend towards maturation. Fragmented moist deciduous forests seek immediate attention as they represent spatial habitat for many economical or ecological important species, thus sustaining local biodiversity for livelihoods. 1. Introduction Small forest fragments or areas lying outside fully protected zones maintain a significant number of species and their genetic diversity [1, 2]. Even forest patches of less than 1?ha in size could play major roles in maintenance of regional biodiversity [3]. During the past several years, large complexes of natural habitat have been converted into agricultural, industrial, or urbanized landscapes, leading to severe loss of the original habitat and an increasing fragmentation of the remnant patches [4]. High fragmentation rate stimulate habitat modifications and the loss of valuable portions of the forest ecosystem, the number of rare and shade - tolerant species increases due to fragmentation especially during recovery at the early successional stage [5]. Tree species with small population will be the first to be lost in the process of forest fragmentation
In Vitro-In Vivo Correlation Evaluation of Generic Alfuzosin Modified Release Tablets
Utpal Kumar Sanki,Badal Kumar Mandal
ISRN Toxicology , 2012, DOI: 10.5402/2012/813836
Murugesh Shivashankar,Badal Kumar mandal,Roshini Yerappagari,Venkatesan Praveen Kumar
International Research Journal of Pharmacy , 2011,
Abstract: Chitosan is a natural polymer obtained by deacetylation of chitin. It is biologically safe, non-toxic, biocompatible and biodegradable polysaccharide. Chitosan is a good candidate for site-specific drug delivery. Hydro gels are potential candidates in controlled release applications. It is due to their soft tissue biocompatibility, the ease with which the drugs are dispersed in the matrix and high degree of control achieved by selecting physical and chemical properties of polymer network. The aim of this review is to provide insight into the applications of chitosan based hydro gels for the drug delivery through different routes. These chitosan-based hydro gels are very essential in the sustained release of antibiotics to reach the target site. This article reviews focused on entire features of chitosan-based hydrogles in both as a drug delivery matrix system and a system for tissue engineering as well as its potential therapeutic applications. Finally it can be concluded that chitosan-based hydro gels offers a novel way for the sustained release of drugs to treat localized infections.
Speciation of Chromium in Soil and Sludge in the Surrounding Tannery Region, Ranipet, Tamil Nadu
Badal Kumar Mandal,Raviraj Vankayala,L. Uday Kumar
ISRN Toxicology , 2011, DOI: 10.5402/2011/697980
Application of Response Surface Methodology for Optimization of Fluoride Removal Mechanism by Newely Developed Biomaterial  [PDF]
Ria Bhaumik, Naba Kumar Mondal, Soumya Chattoraj, Jayanta Kumar Datta
American Journal of Analytical Chemistry (AJAC) , 2013, DOI: 10.4236/ajac.2013.48051

The adsorption capacities of new biomaterials derived from lemon leaf (Citrus sp.) toward fluoride ions have been explored by varying different physicochemical parameters such as pH, initial concentration, adsorbent dose, contact time, stirring rate and temperature. The entire study was done through batch process. Maximum fluoride adsorption of 96.9% - 98.8% was achieved with an initial concentration of 10 mg/L. Langmuir isotherm model well expressed fluoride ad- sorption onto LLD-1, LLD-2 and LLD-3. According to correlation coefficient, the fluoride adsorption onto these 3 ad- sorbents was correlated well with pseudo-second-order kinetic model. From thermodynamic study, the spontaneous nature and feasibility of the adsorption process with negative enthalpy (ΔH0) value also supported the exothermic nature were shown. The rate of fluoride adsorption was mathematically described as a function of experimental parameters and was modeled through Box-Behnken (Response surface methodology). The results showed that the responses of fluoride adsorption were significantly affected by the quadratic term of pH, initial concentration, contact time and temperature and the statistical analysis was performed by ANOVA which indicated good correlation of experimental parameters.

A Note on Hydromagnetic Flow of an Oldroyd-B Fluid near an Infinite Plate Induced by Half Rectified Sine Pulses  [PDF]
Arun Kumar Ghosh, Sanjib Kumar Datta, Pulakesh Sen
Open Journal of Fluid Dynamics (OJFD) , 2014, DOI: 10.4236/ojfd.2014.42017

An initial value problem concerning the motion of an incompressible, electrically conducting, viscoelastic Oldroyd-B fluid bounded by an infinite rigid non-conducting plate is solved. The unsteady motion is generated impulsively from rest in the fluid due to half rectified sine pulses subjected on the plate in its own plane in presence of an external magnetic field. It is assumed that no external electric field is acting on the system and the magnetic Reynolds number is very small. The operational method is used to obtain exact solutions for the fluid velocity and the shear stress on the wall. Quantitative analysis of the results is presented with a view to disclose the simultaneous effects of the external magnetic field and the fluid elasticity on the flow and the wall shear stress for different periods of pulsation of the plate. It is also shown that the classical and hydromagnetic Rayleigh solutions appear as the limiting cases of the present analysis.

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