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PubMed | Saha Institute of Nuclear Physics and Government General Degree College
Type: Journal Article | Journal: Journal of fluorescence | Year: 2016

We present here a detailed photophysical study of a recently synthesised fluorophore 8-methyl-8,9-dihydro-5H-[1,3]dioxolo[4,5-b]carbazol-6(7H)-one. This is a synthetic precursor of bio-active carbazole skeleton Clausenalene. Spectroscopic investigation of the fluorophore has been carried out in different protic and aprotic solvents, as well as in binary solvent mixtures, using absorption, steady-state and time-resolved fluorescence techniques. This fluorophore is particularly responsive to the hydrogen bonding nature as well as polarity of the solvent molecules. When considered in micelles and -cyclodextrin, this behaves as a reporter of its immediate microenvironment. Steady state and time resolved fluorometric and circular dichroism techniques have been used to explore the binding interaction of the fluorophore with transport proteins, bovine serum albumin and human serum albumin. The probable binding sites of the fluorophore in the proteinous environments have been evaluated from fluorescence resonance energy transfer study. Laser flash photolysis experiments also have been performed to observe the triplet excited state interaction between the fluorophore and albumin proteins.

Das K.,A B N Seal College | Acharya N.,Government General Degree college | Kundu P.K.,Jadavpur University
Journal of the Korean Physical Society | Year: 2015

This paper is devoted to an investigation of the influences of thermal radiation on an unsteady, mixed, convection boundary layer flow and the heat transfer over a vertical heated permeable stretching sheet embedded in a porous medium. Different models of the nanofluid based on different formulae for the thermal conductivity and the dynamic viscosity and their effects on the fluid flow and the heat transfer characteristics are discussed. Using the similarity transformation, we transform the governing equations into similarity, non-linear, ordinary differential equations which are solved by employing a numerical shooting technique with a fourth-order Runge-Kutta integration scheme. The obtained results are presented graphically, and the physical aspects of the problem are discussed. © 2015, The Korean Physical Society.

PubMed | Krishnagar Government College and Government General Degree College
Type: Journal Article | Journal: Cell biology international | Year: 2015

Several signaling molecules critically regulate the physiological responses in plants. Among them, miRNAs, generally 21-24 nucleotides long, are widely distributed in different plant species and play as key signaling intermediates in diverse physiological responses. The mature miRNAs are synthesized from MIR genes by RNA polymerase II and processed by Dicer-like (DCL) protein family members associated with some accessory protein molecules. The processed miRNAs are transported to the cytoplasm from the nucleus by specific group of transporters and incorporated into RNA-induced silencing complex (RISC) for specific mRNA cleavage. MicroRNAs can suppress the diverse gene expression, depending on the sequence complementarity of the target transcript except of its own gene. Besides, miRNAs can modulate the gene expression by DNA methylation and translational inhibition of the target transcript. Different classes of DCLs and Argonaute proteins (AGOs) help the miRNAs-mediated gene silencing mechanism in plants.

Jha T.B.,Barasat Government College | Nath S.,Government General Degree College
Nucleus (India) | Year: 2016

Determination of chromosome number and their analysis particularly in vast number of economically important medicinal tree species are far from complete. Chromosome analysis provides information on chromosomal behaviour and identifies the plant with a particular karyotype formula which is the basis of genome analysis in a particular species. The present communication considered two medicinally important almost unattended Indian tree species, Bixa orellana L. and Limonia acidissima L., for chromosomal analysis using an improved cytogenetic protocol of Enzymatic Maceration and Air drying (EMA) method followed by Giemsa staining [5]. Chromosome analysis of Bixa orellana reveals to contain 2n = 14 chromosomes with karyotype formula represented by 4 M + 10 m. Chromosomes are relatively smaller in size (1.30–3.40 μm) and total chromatin length varies from 24 to 30 μm among the observed metaphase plates. Karyotype is bimodal due to the presence of a visibly long pair of chromosomes which are almost two times longer than all other pairs. Limonia acidissima L. confirms to contain 2n = 18 chromosomes and has a karyotype formula of 16 m + 2 m.t. Chromosomes are relatively smaller in size (1.53–2.83 μm) and total chromatin length varies from 32 to 43.5 μm among observed metaphase plates. Both the species show symmetrical karyotype with predominance of chromosomes showing median or nearly median primary constrictions. These chromosomal data will be useful in genome analysis of these economically important plant species for future improvement programmes. © 2016, Archana Sharma Foundation of Calcutta.

Anirban Sk.,University of Burdwan | Anirban Sk.,Government General Degree College | Dutta A.,University of Burdwan
RSC Advances | Year: 2015

Defect associates and their interactions with charge carriers, influencing the ion dynamics have been discussed for Gd3+ and Y3+ co-doped nanocrystalline ceria. Detailed Rietveld analysis of the X-Ray Diffraction data confirmed the single phase cubic fluorite structure of the compositions with the space group Fm3¯m. An overall increase of the lattice parameter with Gd3+ ion concentration has been found. Grain and specific grain boundary conductivity have been evaluated from the complex impedance plots. A higher value dielectric constant has been observed for a co-doped sample at 20 mol% doping concentration. The interaction between dopant cations with oxygen vacancies has been found to form different defect associates and defect clusters. The association energy of co-doped samples at a 20 mol% doping concentration is observed to be a minimum in comparison with the singly doped samples of the same concentration. It has also been found that different defect clusters have a significant role on ionic conduction. The correlation among structural parameters, dielectric and conductivity responses has been discussed and established. © The Royal Society of Chemistry.

Anirban S.,University of Burdwan | Anirban S.,Government General Degree College | Paul T.,University of Burdwan | Dutta A.,University of Burdwan
RSC Advances | Year: 2015

The oxygen vacancy evolution and ion dynamics in Dy doped nanoceria have been investigated with microstructural, optical and ionic conductivity studies. The influence of Dy3+ ions on the microstructures and the optical and ionic conductivity properties of these nanoparticles has been studied using X-ray diffraction, HR-TEM, EDAX, UV-vis, Raman and impedance spectroscopy. From Rietveld refinement of the XRD profiles, it has been found that the oxygen vacancies, lattice parameters and Ce-O bond lengths increase with Dy3+ ion concentration. The Rietveld analysis, together with HR-TEM, confirms the cubic fluorite structure with space group Fm3m of all the samples. The EDAX spectra show good stoichiometry of the different atoms in the samples. The direct band gap, calculated from UV-vis spectra, shows a red shift with increasing concentration of Dy3+ ions. Raman spectroscopy studies of the samples gave insight into their vibrational properties and pointed to the fact that the oxygen vacancy content increased significantly with the doping concentration. The number of oxygen vacancies and their interaction with dopant cations strongly influence the electrical properties of Dy doped ceria. This journal is © The Royal Society of Chemistry.

Anirban S.,University of Burdwan | Anirban S.,Government General Degree College | Dutta A.,University of Burdwan
RSC Advances | Year: 2016

Ion dynamics in pure and Dy containing nanoceria has been investigated in the light of different defect associates and their mutual interactions. The samples were prepared through citrate-nitrate auto-ignition method and their single-phase cubic fluorite structure was confirmed from X-ray diffraction and high resolution transmission electron microscopy analysis. The complex impedance spectra showed both grain and grain boundary contribution to total conductivity. The concentration dependent conductivity variation has been discussed with the help of oxygen vacancy concentration and their interactions with the defect associates. The frequency dependence of dielectric permittivity and electric modulus has been analyzed using Havriliak-Negami formalism. The relaxation mechanism is found to be dependent on the formation of different dimers and trimers. Modulus analysis has established the charge re-orientation relaxation of the defects associates. The time-temperature superposition principle has been established by scaling of different spectra. © 2016 The Royal Society of Chemistry.

Anirban S.,University of Burdwan | Anirban S.,Government General Degree College | Dutta A.,University of Burdwan
Solid State Ionics | Year: 2016

In this work, microstructural, charge carrier dynamics and dielectric relaxation properties of triple rare earth (Praseodymium, Samarium and Europium) doped ceria nanomaterials have been investigated. The microstructural investigation of the compositions has been done using Rietveld analysis of X-Ray Diffraction data. The total conductivity was found to depend on oxygen vacancy, dopant vacancy interaction and charge carrier concentration. The highest ionic conductivity was obtained for the composition containing Pr = 0.15 and Sm/Eu = 0.075. The temperature dependence of conductivity was found to follow the Vogel–Tammann–Fulcher (VTF) relation. The complex dielectric permittivity and electric modulus have been investigated using Havriliak–Negami function. The shape parameters obtained from modulus spectra and the frequency exponent obtained from conductivity spectra were found to be slightly temperature dependent. The small polaron hopping in localized states and correlated barrier hopping conduction mechanism were confirmed from complex conductivity data. The temperature independent nature of conductivity and relaxation mechanism was confirmed from master plots of modulus and conductivity spectra. The reciprocal temperature dependence of the relaxation times obtained from electrical properties was also found to follow VTF relation. © 2016 Elsevier B.V.

Chatterjee K.,Government General Degree College
Rupkatha Journal on Interdisciplinary Studies in Humanities | Year: 2016

This paper seeks to look at the culinary associations of Jhumpa Lahiri's Interpreter of Maladies to explore the metaphor of food as it is employed by Lahiri to delineate different shades and nuances of the lives of mostly the expatriate people, concentrating especially on how food negotiates the unease in living in an adopted land. The first section of this paper introduces the critical issues related to food and eating, and the second section moves on to the analysis of her short story collection Interpreter of Maladies, relating the stories to the issues discussed in the first section of the paper.

Bhar P.,Government General Degree College | Murad M.H.,Brac University
Astrophysics and Space Science | Year: 2016

This paper presents a new model of static spherically symmetric relativistic charged stellar objects with locally anisotropic matter distribution together with the Chaplygin equation of state. The interior spacetime has been matched continuously to the exterior Reissner–Nordström geometry. Different physical properties of the stellar model have been investigated, analyzed, and presented graphically. © 2016, Springer Science+Business Media Dordrecht.

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