Authors:D. Nayak, K. Hazra, S. Laskar, and S. Lahiri
The present study has been performed to preconcentrate gold using the proteins extracted from Mimusops elengi Linn. (Family: Sapotaceae) seed by radiometric technique using 198Au. Effects of buffer and pH dependence on the binding affinity of the gold have also been examined. It has been found that
the binding of gold with M. elengi protein neither depends on the addition of buffer nor the composition (phosphate/citrate) of buffer. The adsorption of gold
is also independent of pH of the solution. To verify the gold-protein interaction, inter-comparisons have been made between
four different approaches, (1) notably extraction with anion-exchange resin Amberlite IRA 400, (2) trichloroacetic acid (TCA)
precipitation, (3) isoelectric precipitation and (4) dialysis of protein after incubation with gold. Good agreement has been
observed for all the cases. Binding of gold have been studied with three different concentrations of gold, 1, 10 and 50 ppm
spiked with 198Au.
Authors:D. Nayak, A. Banerjee, S. Roy, and S. Lahiri
Attempt has been made to develop methodologies for preconcentration of chromium in the biodegradable polymer beads. The uptake
behaviors for chromium have been studied with Ca-alginate (CA) and Fe-doped calcium alginate (Fe-CA) beads. The work also
aims to study the differential attitude of CA and Fe-CA towards Cr(III) and Cr(VI) so that, depending on the oxidation state
of chromium effluent, environmentally sustainable methodologies can be prescribed for removal of chromium. Radiotracer 51Cr has been chosen as precursor of stable chromium throughout the experiment. It was found that Fe-CA beads are suitable for
removal of Cr(III) and Cr(VI) while CA beads can be used for the speciation and separation of Cr(III) and Cr(VI) at pH 5.
Authors:N. Chakraborty, R. Pal, A. Ramaswami, D. Nayak, and S. Lahiri
The bioaccumulation of gold in trace concentration by Nitzschia obtusa and Navicula minima, two members of bacillariophyceae, has been studied. It has been observed that Nitzschia obtusa showed better accumulation of gold in acidic pH in comparison to neutral and basic pH. Maximum accumulation was observed
with 1 mg . kg-1 or less gold concentration. However, the accumulation by the living cells was reduced when the matrix concentration was higher. Navicula minima, on the other hand, found to be a better accumulator of gold in wide ranges of pH and substrate concentration of the media.
It was also inferred that the gold accumulation by diatom was mainly due to adsorption by biosilica (siliceous frustules of
dead diatom cells). Accumulated gold was recovered with conc. HNO3.
Authors:D. Nayak, S. Lahiri, A. Mukhopadhyay, and R. Pal
The bio-sorption of heavy and toxic radionuclides by three genera of algae from different taxonomic groups was studied employing the recently developed 'Tracer Packet' technique. The tracer packet of heavy and toxic metals' contained 197Hg, 198,199,200,201Tl, 199,200,201Pb, 204Bi and 204,205Po radionuclides in carrier-free state and was produced by irradiating a gold metal foil with medium energy 7Li and 12C beams successively in a 12 MV Pelletron. Three genera, Spirulina from Cyanophyceae, Oedogonium from Chlorophyceae and Catenella from Rhodophyceae were cultured in laboratory condition and were used in the experiment. The radionuclide accumulation varied according to different genera at different pH levels. At basic pH Spirulina showed a maximum radionuclide accumulation in comparison to other genera.
Authors:R. Prasanna, A. Sood, A. Suresh, S. Nayak, and B. Kaushik
A wide variety of pigments, like chlorophyll, carotenoids and phycobiliproteins, which exhibit colours ranging from green, yellow, brown to red are present in algae. Increasing awareness of harmful effects of synthetic dyes and inclination of society towards the usage of natural products, such as plant / microbial based colours in food and cosmetics, has led to the exploitation of microalgae as a source of natural colours. Algal pigments have great commercial value as natural colorants in nutraceutical, cosmetics and pharmaceutical industry, besides their health benefits.
capsules are now commonly prescribed health foods for improving vitality and longevity of human beings. This review describes the distribution, structure of these pigments in algae, with emphasis on specific techniques for extraction and purification, along with different methods of biomass production and commercially feasible techniques documented in literature. An overview of the industrial applications of these natural colouring agents in diagnostics, food and cosmetics industry is also provided.
Authors:S. Lahiri, D. Nayak, S. Das, A. Ramaswami, S. Manohor, and N. Das
Charged particle activation of natural CeO2 with ≈80 MeV16O7+ results in the formation of carrier free isotopes,151, 152, 153Dy and their daughter products,151, 152, 153Tb, in the matrix. The liquid cation exchanger HDEHP, has effectively been utilised as an extractant in the quantitative separation
of the activation products namely151, 152, 153Dy,151, 152, 153Tb from the bulk target matrix of ceric oxide.
Authors:D. Nayak, M. Nag, S. Banerjee, R. Pal, S. Laskar, and S. Lahiri
bioaccumulation of 198Au radionuclide, by Rhizocloniumriparium
a member of Chlorophyceae has been studied. It has been observed that
accumulation of gold on Rhizoclonium is almost pH independent and
slightly higher at basic pH. Accumulation of gold was studied with 198Au
radiotracer, 0.1, 1 and 5 ppm concentrations of gold. It has been concluded
from the biochemical analysis that the gold accumulation is due to adsorption
in the cellulose and not in protein, fat and carbohydrate. Accumulated gold was
recovered when washed with conc. HNO3.
Authors:N. Ramamoorthy, S. Balakrishnan, S. Gaitonde, P. Pandey, U. Nayak, M. Patel, R. Patel, and P. Ramanathan
Methods for the preparation and analysis of a new renal radiopharmaceutical,99mTc-thiodiglycolic acid (TDGA), are reported. The kit for Tc-TDGA contains a lypophilized acidic (pH 2.5) mixture of 5 mg TDGA and 0.05 mg SnCl2·2H2O. Acetate buffer has been found to be a suitable solvent for paper chromatography of99mTc-TDGA. The results of the quantitative organ distribution studies in rats and rabbits indicated the characteristics of99mTc-TDGA to be intermediate to the renal tubular agent131I-Hippuran and the GFR agent99mTc-DTPA.
Authors:P. Nayak, D. Das, S. Chintalapudi, P. Singh, S. Acharya, V. Vijayan, and V. Chakravortty
Two representative titaniferous magnetite samples procured from Moulabhanj, Orissa, India have been studied by PIXE, EDXRF, Mössbauer spectroscopy, and XRD techniques. Major iron-bearing phases identified in the samples by Mössbauer spectroscopy and XRD are magnetite, hematite, ferrous ilmenite and ferric ilmenite. The Fe2+/Fe3+ ratio and the relative percentages of different minerals were determined from the resonance areas of Mössbauer spectra. Quantitative multielemental analysis was carried out by energy dispersive X-ray fluorescence (EDXRF) and proton induced X-ray emission (PIXE). Nineteen minor and trace elements have been quantified by EDXRF whereas by PIXE eighteen elements have been analyzed quantitatively. Concentrations of trace elements determined by EDXRF and PIXE were used in interpreting the physico-chemical condition of the depositional basin.
Authors:M. Ashok, T. Rautray, Pranaba Nayak, V. Vijayan, V. Jayanthi, and S. Narayana Kalkura
The elemental analysis of south Indian gallstones has been carried out using energy dispersive X-ray fluorescence (EDXRF) spectroscopy. A number of important elements including Fe, Cu, Zn, Br, and Pb were estimated from the EDXRF spectra. The results are presented and discussed.