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Abstract  

Niobium and tantalum which have close chemical similarities have been separated through two different methods, viz. solvent extraction and reversed phase extraction chromatography (RPEC) in tracer scale using Aliquat 336 as a liquid anion exchanger. Quantitative extraction of tantalum in the organic phase from 0.05M HF solution by 5·10–4M Aliquat 336 solution was achieved leaving niobium in the aqueous phase. In RPEC, hydrophobized kieselguhr impregnated with Aliquat 336 was used as the stationary phase in the column from which niobium was first eluted with 0.1M HF and then tantalum with 10M HNO3 solution. The purity of the separated isotopes in both the procedures were verified by means of gamma-ray spectrometry.

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Abstract  

Effective separation of the congeneric pair of elements, zirconium and hafnium and also niobium which was in admixtures with zirconium as daughter in its isotopic form were achieved through reversed phase column and paper extraction chromatographic procedures using di-(2-ethylhexyl)phosphoric acid (HDEHP) as the liquid exchanger. In reversed phase column chromatographic separation, the tracers,95Zr,95Nb and175,181Hf, were extracted by HDEHP impregnated on kieselguhr and were sequentially eluted with 6N H2SO4+xN oxalic acid+H2O2(where x=0.1, 0.5 and 2). Similarly, in reversed phase paper chromatographic study in which a coating of HDEHP on Whatman No. 1 chromatographic paper was used as stationary phase, the mobile phase, 18N H2SO4+0.1N oxalic acid + H2O2, helped in separating the elements with favorable separation factors. Under the optimal conditions, the separation and decontamination of the elements in both methods were found to be quantitative, as verified by -spectrometric studies.

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Abstract  

A radiometric procedure for quantitative analysis of traces of silver in galena has been demonstrated. The mineral sample was dissolved in HNO3 (31) and silver present in the solution was precipitated as insoluble AgI by adding an excess amount of131I-labeled KI solution and was coprecipitated with zirconium hydrogen phosphate, Zr(HPO4)2, in 0.5N H2SO4 medium. The method of radiometric analysis of silver which was estimated from the knowledge of the loss of131I activity in solution, was found to be effective in determination of the element even below ppb level. Applicability of the radiometric procedure in routine analysis or preconcentration of traces of silver in galena has been stressed.

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Autophagy is a catabolic process through which damaged or long-lived proteins, macromolecules and organelles are degraded using lysosomal degradative machinery. Since cardiac myocytes are terminally differentiated, the role of autophagy is essential to maintain the homeostasis of the myocardium. Autophagy supplies nutrients for the synthesis of essential proteins during starvation and thus helps to extend cell survival. Although autophagy is non-selective, under oxidative conditions it effectively removes oxidatively damaged mitochondria, peroxisomes and endoplasmic reticulum. Thus, autophagy can protect the cells from apoptosis and other major injuries, and it is considered to be in the cross-road between cell death and survival. However, excess autophagy can destroy essential cellular components and lead to cell death. The function of autophagy in normal and in the conditions of cardiac diseases such as heart failure, cardiomyopathy, cardiac hypertrophy, and ischemia-reperfusion injury is discussed.

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Abstract

Single crystals of pure triglycine sulfate (TGS) and potassium chloride (KCl)-doped TGS with different concentrations (0.2, 0.4, 0.6, and 1 mol%) were grown from aqueous solutions by natural evaporation process at room temperature. Thermal stability of the grown crystals was investigated by differential thermal analysis (DTA) and thermogravimetric (TG) studies. DTA curve shows a lower decomposition temperature for KCl-doped TGS crystal than that of pure TGS crystal. The dielectric properties of pure TGS and KCl-doped TGS crystals were performed in the frequency range of 1–500 kHz at 30 °C and this study showed that the dielectric constant was increased due to KCl concentration. DC electrical conductivity measurements were made in the temperature range from 35 to 100 °C and showed that the DC conductivity was increased with the increase of temperature as well as doping concentrations of KCl. The etching feature of the surface of the grown crystals was studied in water etchant.

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Abstract  

Carrier free promethium was produced by proton activation in neodymium target. Extraction behavior of both the elements were studied by HDEHP. A pronounced synergism had been observed by the binary mixture of HDEHP and PC88A. Presence of H2O2 in aqueous phase also increases the separation factor.

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Abstract  

Carrier-free radionuclides of mercury and gold192,193Hg and192,193Au have been produced by heavy ion activation of tantalum target with 95 MeV16O5+ beam obtained from an ECR ion source. An effective radiochemical separation scheme has been developed to isolate gold and mercury radionuclides from the tantalum target matrix.

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Abstract  

Trace level tantalum and rhenium, 182Ta and 186,188Re, have been separated with liquid anion exchanger, TOA from HNO3 medium. The feasibility of the separation process has also been verified for the separation of trace level rhenium from bulk or macro quantity of tantalum. The developed radiochemical scheme will be useful for the separation of carrier-free rhenium radionuclides produced in -particle activated matrix target.

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Abstract  

Present investigation deals with neutron activation analysis of gold in some varieties of geological samples related to auriferous quartz veins. A few plant specimens of the area were also analyzed. The gold contents in the rock samples as determined by the destructive way of analysis vary in the range 10−5 to 10−7%. In case of plant samples, however, the non-destructive method of analysis of the plant ashes was followed and the concentration of gold was found to be of the order of 10−5%. In plants, besides gold, some associated elements, such as La, Ce, Sm, Lu, Zr, Hf, Se, W, As and Sb were also identified.

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