Doctoral Education and Academic Research (in India)

[Excerpt] The state of doctoral education and academic research in India is poor and the country has scant representation among the world’s great universities. The decline has happened in spite of early achievements. Reasons behind this are complex and defy easy explanations. Several probable causes in terms of resources / facilities / opportunities granted to Ph.D. students, faculty quality, financial resources, academic leadership and other issues are explored and some suggestions for improvement are provided

Studies on surfactant-biopolymer interaction. II. Interaction of cetyl trimethyl ammonium-, cetyl ethanolyl dimethyl ammonium-, cetyl diethanolyl methyl ammonium- and cetyl triphenyl phosphonium bromides and cetyl pyridinium chloride with calf thymus DNA

205-215The interaction of the surfactants cetyl trimethyl arnrnonium-, cetyl ethanolyl dimethyl ammonium-, cetyl diethanolyl methyl arnmonium-, and cetyl triphenyl phosphonium bromides and cetyl pyridinium chloride with calf thymus DNA was studied at 303 K in phosphate buffer (pH 7.0) at 10 <span style="mso-bidi-font-family:Arial;mso-bidi-language: HI">mM NaCI using spectrophotometric, viscometric, tensiometric, dynamic light scattering, circular dichroism, fluorescence microscopic and microcalorimetric techniques. All the surfactants interacted fairly with DNA, making the biopolymer condensed, even to the aggregated globular configuration at higher [surfactant]/[DNA] mole ratio (R), with direct evidence from fluorescence microscopy. Melting temperature and light scattering intensity of the DNA increased, whereas viscosity decreased in the presence of the surfactants. Tensiometry evidenced effective interaction at [surfactant] as low as 7.6 µM. Isothermal titration calorimetric measurements supported low enthalpy of binding, induced aggregation of the surfactants, increased critical micellar concentration and association of aggregates with the biopolymer at higher R, evidencing distinctions in thermal behaviour. </span

Adsorption of methylene blue on cellulose from its own solution and its mixture with methyl orange

611-617The adsorption behaviour of the cationic dye, methylene blue (MB) from its own solution and from its mixture with an anionic dye, methyl orange (MO) on cellulose has been investigated. The effects of temperature and KCl on the adsorption process have been examined. The anionic dye, MO neither individually nor in mixed condition adsorbs on the negatively charged cellulose surface under the studied conditions of temperature and ionic strength. The dye MB alone and from its mixture with MO adsorbs on the cellulose surface, the former shows lower extent of adsorption than the latter. At a temperature >303 K, the mixed dyes MB and MO undergo complexation. The results have been analysed in the light of the adsorption isotherms of Freundlich, Frumkin and Langmuir and related adsorption thermodynamics

Effects of additives (NaCl, urea, glucose, guanidine hydrochloride) on the physico-chemical properties of reverse micelles of Tweens in chloroform

589-597The physico-chemical properties, viz, critical micelle concentration (CMC) of reverse micelle(s) and binding of the dye Safranine T (3,7 diamino-2, 8 dimethyl-5-phenyl phenazinium chloride) with the reverse micelle (RM) of water/TweenChloroform in the presence of varied concentrations of the additives (sodium chloride, glucose, urea and guanidine hydrochloride), have been investigated. While the first reduces the CMC of the studied RM system, the latter three increase it. The binding efficiency of the dye is likewise affected by the additives. An attempt has been made to rationalize the results on physico-chemical basis

Characterization of reverse micelles by spectroscopic measurements

1210-1213The w/o microemulsions formed with the surfactant AOT and different oils have been characterized by absorption, emission and dynamic light scattering measurements. The threshold [H2O]/[AOT] ratio (ω) for the zero free water in the microwater pool of the reverse micelles has been evaluated and has been observed to be oil-dependent. The hydrodynamic diameter of the dispersed water droplets has been found to be oil -dependent and follows the order: cyclohexan

Salt effects on surfactant aggregation and dye-micelle complexation

137-143Physical parameters for characterizing the structure of micelles are necessary for their surface chemical understanding. The effects of salts on physical characteristics (viz. critical micelle concentration, aggregation behaviour, counter ion binding, dye binding, etc.) of micelles have been investigated. The critical micelle concentration of ionic surfactant (sodium dodecylsulphate) has been found to decrease with addition of salt while for nonionic surfactants (Tweens) the change is insignificant.The aggregation number as well as safranine T and phenosafranine micelle binding constants show increase for ionic micelles in salt environment. The effects of salt in the above regards on nonionic micelles are negligible