Jagannath Barooah College

Jorhāt, India

Jagannath Barooah College

Jorhāt, India
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Borthakur T.,Jagannath Barooah College | Sarma R.,Jagannath Barooah College
Applied Physics A: Materials Science and Processing | Year: 2017

We have investigated the effect of perylene interlayer between the organic/electrode interface on the electrical performance of a top contact pentacene-based OTFT. We have found the performance enhancement of the OTFT device. The OTFT devices with perylene layer show better field effect mobility and on–off ratio than that of having only metal electrodes. It also lowers the subthreshold slope and threshold voltage compared to single-layered OTFT devices. © 2017, Springer-Verlag Berlin Heidelberg.

Patowary K.,Institute of Advanced Study in Science and Technology | Saikia R.R.,Jagannath Barooah College | Kalita M.C.,Gauhati University | Deka S.,Institute of Advanced Study in Science and Technology
Annals of Microbiology | Year: 2015

An efficient hydrocarbon-degrading native bacterial strain Bacillus pumilus KS2 (identified by partial 16S rDNA gene sequencing) was isolated from crude oil-contaminated soil collected from oil fields of Lakowa, Sivasagar district of Assam, India. Experiments were conducted under laboratory conditions to determine the efficiency of this biosurfactant-producing strain to degrade polycyclicaromatic hydrocarbons (PAHs). Quantification of the capacity of the biosurfactant to reduce the surface tension (ST) of the culture medium was used as a measure of biosurfactant production. In terms of total petroleum hydrocarbon (TPH) degradation, strain KS2 was able to degrade 80.44 % of the TPH by 4 weeks of incubation. It also demonstrated efficient degradation of PAHs, completely degrading nine of the 16 major PAHs present in the crude oil sample. Strain KS2 also produced biosurfactant which, based on biochemical and FTIR analyses, was glycolipid in nature. To our knowledge, this is the first report showing the potential of a native strain of the North-East region of India for efficient degradation of TPH and PAHs and, consequently, in the remediation of hydrocarbons from contaminated sites. © 2014, Springer-Verlag Berlin Heidelberg and the University of Milan.

Mazumder N.,Manipal University India | Deka G.,National Taiwan University | Wu W.-W.,Taipei City Hospital | Gogoi A.,National Yang Ming University | And 3 more authors.
Methods | Year: 2017

Second harmonic (SH) microscopy has proven to be a powerful imaging modality over the past years due to its intrinsic advantages as a multiphoton process with endogenous contrast specificity, which allows pinhole-less optical sectioning, non-invasive observation, deep tissue penetration, and the possibility of easier signal detection at visible wavelengths. Depending on the relative orientation between the polarization of the incoming light and the second-order susceptibility of non-centrosymmetric structures, SH microscopy provides the unique capacity to probe the absolute molecular structure of a broad variety of biological tissues without the necessity for additional labeling. In addition, SH microscopy, when working with polarimetry, provides clear and in-depth insights on the details of molecular orientation and structural symmetry.In this review, the working principles of the polarization resolving techniques and the corresponding implements of SH microscopy are elucidated, with focus on Stokes vector based polarimetry. An overview of the advancements on SH anisotropy measurements are also presented. Specifically, the recent progresses on the following three topics in polarization resolved SH microscopy will be elucidated, which include Stokes vector resolving for imaging molecular structure and orientation, 3-D structural chirality by SH circular dichroism, and correlation with fluorescence lifetime imaging (FLIM) for in vivo wound healing diagnosis. The potentials and challenges for future researches in exploring complex biological tissues are also discussed. © 2017 Elsevier Inc.

Boruah M.J.,Tezpur University | Gogoi A.,Jagannath Barooah College | Gogoi A.,National Yang Ming University | Nath B.C.,Tezpur University | Ahmed G.A.,Tezpur University
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2017

Fayalite (Fe2Si04), the iron end-member of the olivine group, is found in various extraterrestrial environments including the interstellar medium and meteorite. Since the iron rich silicates, i.e. fayalites, are not abundantly found in earth, there has been lack of sufficient experimentation and modeling leading to the unavailability of sufficient experimental data of fayalite for comparative analyses with computations and astrophysical observations. In this work interstellar fayalite dust analogues were synthesized in the laboratory using simple chemical route. Shape and size dispersed interstellar dust analogue models for laboratory synthesized fayalite particles were developed for performing theoretical computations of light scattering parameters (e.g., angular profiles of intensity and degree of linear polarization, geometric and single-scattering albedo, asymmetry parameter and cross-sections of extinction and absorption) using discrete dipole approximation (DDA). In order to demonstrate the validity of our models, phase function and degree of linear polarization were measured using a laboratory based setup and the results were compared with DDA computed theoretical values at three wavelengths 543.5 nm, 594.5 nm and 632.5 nm respectively. © 2017 Elsevier Ltd

Borthakur T.,Jagannath Barooah College | Sarma R.,Jagannath Barooah College
Indian Journal of Physics | Year: 2017

Top-contact Pentacene-based organic thin film transistors (OTFTs) with a thin layer of Vanadium Pent-oxide between Pentacene and Au layer are fabricated. Here we have found that the devices with V2O5/Au bi-layer source–drain electrode exhibit better field-effect mobility, high on–off ratio, low threshold voltage and low sub-threshold slope than the devices with Au only. The field-effect mobility, current on–off ratio, threshold voltage and sub-threshold slope of V2O5/Au bi-layer OTFT estimated from the device with 15 nm thick V2O5 layer is.77 cm2 v−1 s−1, 7.5×105, −2.9 V and.36 V/decade respectively. © 2017, Indian Association for the Cultivation of Science.

Ahmed G.A.,Tezpur University | Gogoi A.,Jagannath Barooah College
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2014

The analysis of optical scattering data of interstellar carbonaceous graphite dust analog at 543.5. nm, 594.5. nm and 632.8. nm laser wavelengths by using an original laboratory light scattering setup is presented. The setup primarily consisted of a laser source, optical units, aerosol sprayer, data acquisition system and associated instrumentation. The instrument measured scattered light signals from 10° to 170° in steps of 1°. The results of the measurements of the volume scattering function β(θ) and degree of linear polarization P(θ) of the carbonaceous graphite dust particles that were sprayed in front of the laser beam by using an aerosol sprayer were subsequently compared with theoretically generated Mie plots with estimated parameters. © 2013 Elsevier Ltd.

Das S.K.,Jagannath Barooah College | Sabhapondit S.,Tocklai Experimental Station | Ahmed G.,Gauhati University | Das S.,Tocklai Experimental Station
Biochemical Genetics | Year: 2013

To verify the quality of triploid varieties of Camellia tea species at the secondary metabolite level, we tested caffeine and catechin profiles of 97 F1 segregating progenies in two breeding populations with a common tetraploid parent and diploid parents of two geographic and varietal origins. Catechin and caffeine levels of the triploid progenies were quantified and compared against their diploid parent. Some of the progenies showed better performance than their diploid parent. Most of the progenies of the diploid C. sinensis × tetraploid cross showed heterosis for caffeine and EGCG. Progenies of the C. assamica subsp. lasiocalyx × tetraploid cross showed heterosis for +C, EC, EGC, and TC. The genomic contributions of the diploid parent seem to be the main factor in the variation between the two populations. Our studies showed quantitative enhancement of some of the quality-related parameters in tea, providing a platform to refocus on this classical breeding approach for developing quality cultivars in tea. © 2013 Springer Science+Business Media New York.

Baruah P.,Institute of Advanced Study in Science and Technology IASST | Saikia R.R.,Jagannath Barooah College | Baruah P.P.,Gauhati University | Deka S.,Institute of Advanced Study in Science and Technology IASST
Environmental Science and Pollution Research | Year: 2014

Chlorophyll plays a pivotal role in the plant physiology and its productivity. Cultivation of plants in crude oil contaminated soil has a great impact on the synthesis of chlorophyll pigment. Morpho-anatomy of the experimental plant also shows structural deformation in higher concentrations. Keeping this in mind, a laboratory investigation has been carried out to study the effect of crude oil on chlorophyll content and morpho-anatomy of Cyperus brevifolius plant. Fifteen-day-old seedling of the plant was planted in different concentrations of the crude oil mixed soil (i.e., 10,000, 20,000, 30,000, 40,000, and 50,000 ppm). A control setup was also maintained without adding crude oil. Results were recorded after 6 months of plantation. Investigation revealed that there is a great impact of crude oil contamination on chlorophyll content of the leaves of the experimental plant. It also showed that chlorophyll a, chlorophyll b, and total chlorophyll content of leaves grown in different concentrations of crude oil were found to be lower than those of the control plant. Further, results also demonstrated that chlorophyll content was lowest in the treatment that received maximum dose of crude oil. It also showed that chlorophyll content was decreased with increased concentration of crude oil. Results also demonstrated that there was a reduction in plant shoot and root biomass with the increase of crude oil concentration. Results also revealed that the shoot biomass is higher than root biomass. Morphology and anatomy of the experimental plant also show structural deformation in higher concentrations. Accumulation of crude oil on the cuticle of the transverse section of the leaves and shoot forms a thick dark layer. Estimation of the level of pollution in an environment due to oil spill is possible by the in-depth study of the harmful effects of oil on the morphology and anatomy and chlorophyll content of the plants grown in that particular environment. © 2014, Springer-Verlag Berlin Heidelberg.

Sarma R.,Jagannath Barooah College | Saikia D.,Jagannath Barooah College | Konwar K.,Jagannath Barooah College | Baishya B.,Jagannath Barooah College
Indian Journal of Physics | Year: 2010

A study of Pentacene OTFTs using La2O3 as gate insulator is presented. The device characteristics were studied and analyzed. The OTFTs exhibit p-type conductivity with field effect mobility 6.5 × 10-6 m2/V.s, ON/OFF ratio 1.4 × 102, sub-threshold swing 2 mV/decade and hole concentration 4.5 × 10 17 cm-3. The SEM and XRD analysis on the semiconductor film are also reported. © 2010 IACS.

Boruah M.J.,Tezpur University | Gogoi A.,Jagannath Barooah College | Ahmed G.A.,Tezpur University
Planetary and Space Science | Year: 2016

The computation of the light scattering properties of size and shape distributed interstellar graphite dust analogues using discrete dipole approximation (DDA) is presented. The light scattering properties of dust particles of arbitrary shapes having sizes ranging from 0.5 to 5.0 μm were computed using DDSCAT 7.3.0 software package and an indigenously developed post-processing tool for size and shape averaging. In order to model realistic samples of graphite dust and compute their light scattering properties using DDA, different target geometries were generated to represent the graphite particle composition in terms of surface smoothness, surface roughness and aggregation or their combination, for using as the target for DDSCAT calculations. A comparison of the theoretical volume scattering function at 543.5 nm and 632.8 nm incident wavelengths with laboratory simulation is also presented in this paper. © 2016 Elsevier Ltd. All rights reserved.

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