North Eastern Hill University

About: North Eastern Hill University is a education organization based out in Shillong, Meghalaya, India. It is known for research contribution in the topics: Population & Ruthenium. The organization has 2318 authors who have published 4476 publications receiving 48894 citations.

Fluorescence behavior of ethidium bromide in homogeneous solvents and in presence of bile acid hosts

Abstract: Photoluminescence behavior of ethidium bromide (EB) was studied in homogeneous solvents as well as in presence of bile acid surfactants. A quantitative analysis based on Kamlet–Taft equation toward the contribution of different solvatochromic parameters like solvent polarizability ( π * ), hydrogen bond donor ( α ) and hydrogen bond acceptor ( β ) ability, on EB spectral properties reveals that though fluorescence quantum yield and lifetime do not show any straight forward correlation individually, the substantial decrease in these quantities is due to the increase in total nonradiative decay rate in polar protic medium. The interaction of EB with bile acid hosts gives rise to large increase in fluorescence intensity due to shielding of the probe in less hydrogen bonding environment. Global analysis of the fluorescence decay behavior indicates that more than 50% of the fluorophores get sequestered inside the micellar sub-domain with an apparent binding constant of ∼10 3 M −1 .

Karyological studies in ten species of Citrus(Linnaeus, 1753) (Rutaceae) of North-East India.

Abstract: Ten Citrus (Linnaeus, 1753) species of North-East India have been karyo-morphologically analysed. All studied species had 2n=18 chromosomes without any evidence of numerical variation. All the chromosomes were found to be of metacentric and sub-metacentric in all the species; the morphology of the chromosomes showing size difference only. Symmetrical karyotype which does not have much difference in the ratio of longest to shortest chromosome in all the species was observed. Three species, C. grandis (Osbeck, 1757), C. reticulata (Blanco, 1837) and C. medica (Linnaeus, 1753) are identified as true basic species from asymmetry studies of karyotypes as they reflect on the primitive nature of their genomes. C. indica (Tanaka, 1937) occupies a special taxonomic position within the genus Citrus as a progenitor for other cultivated species.