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- Author or Editor: S. Srivastava x
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Abstract
Preliminary results are described of a123Xe filled device to serve as a combination123I generator/iodination kit.123X was produced in the Brookhaven Linac Isotope Producer (BLIP) by the reaction127I(p, 5n)123Xe. The device consists of a small glass ampoule containing an internal glass breakseal and a flanged neck on which was crimped a multi-injection type septum. The ampoule contained a hydrogen sulfide atmosphere to assure that the iodine generated from the decay of the xenon was in the form of iodide. Following an adequate period for123Xe to decay (this period can be used for shipment), a needle is forced through the septum breaking the seal and residual gases are pumped off. The123I in the form of iodide can then be rinsed from the ampoule with any desired solvent or reagent added directly to the device to carry out an iodination in an enclosed environment. Preliminary results of both iodine recovery and iodinations have been promising.
Abstract
The sorption of univalent, bivalent and trivalent ions has been studied on chromium ferrocyanide gel. The studies reveal a high sorption capacity for Cs+, Tl+, Ag+, Cu2+, Zn2+, Cd2+, Fe3+ and Th4+. The sorption of monovalent cations show purely ion-exchange mechanism while the uptake of bivalent and trivalent cations is non-equivalent in nature. Single elution of Rb+, Cs+ and Tl+ has been performed from the columns of this exchanger and the recovery is almost complete in all the cases. Cu2+ and Ag+ get completely adsorbed on the gel column and their elution is not possible probably due to the formation of some new solid phases. Depending on the Kd values of the metal ions, a large number of separations of radiochemical as well as analytical importance can be performed on the columns of this exchanger material.
Commelina benghalensis (Commelinaceae) is widely used as traditional and folklore medicine in India. In the present study, a reverse-phase high-performance liquid chromatography—photodiode array detection (RP-HPLC—PDA) method was developed for the separation, identification, and quantification of bioactive phenolics. Antioxidant potential was also accessed to validate the presence of identified markers. Method was developed on C18 column with 1% formic acid (in water) and acetonitrile as solvent system, and data acquisitions were achieved at wavelength of 285 nm. The developed method was also validated for accuracy, precision, robustness, limit of detection and quantification (LOD and LOQ), repeatability, and recovery according to International Conference on Harmonization (ICH) guidelines. In this method, five phenolics, viz., protocatechuic acid (0.033%), vanillic acid (0.262%), ferulic acid (0.365%), apigenin (0.126%), and kaempferol (0.544%), were quantified in linearity range of 0.2–1.0 μg with correlation coefficient of more than 0.9949. Relative standard deviation (RSD) (%), LOD, LOQ, and recovery (%) are within the acceptable limit. Besides that, methanolic extract shows the inhibition (%) range from 24.45 to 68.75% at 0.02–0.12 mg mL−1. IC50 of extract was observed at 46.75 μg mL−1, suggesting the promising activity in methanol extract. Hence, the proposed method for simultaneous quantification of five bioactive phenolics in the tuber of C. benghalensis using HPLC–PDA detection under the specified conditions is specific and accurate, and validation proves its selectivity and reproducibility.
Abstract
A method for production of no-carrier-added 117mSn (NCA 117mSn) has been developed. It includes proton irradiation of thick antimony targets and chemical recovery of 117mSn by extraction of Sb with dibutyl ether and chromatographic purification on silica gel column. The method provides production of curie amounts of 117mSn with specific activity about 1000 Ci/g and high radionuclidic purity.
Abstract
The kinetics of the decolorization reaction of methyl violet dye (MV) with the hydroxyl ion (nucleophile) was studied in the presence of cationic micelles of cetyltrimethylammonium bromide (CTAB). The reaction follows pseudo-first order kinetics. The rate constant depends on the surfactant concentration. CTAB micelles catalyze the overall reaction between the dye carbocation and the nucleophile. Quantitative analysis of the micellar data obtained has been done by applying positive cooperativity model of enzyme catalysis. For the dye under study, the value of n (index of cooperativity) has been found to be greater than 1. The catalytic effect has been explained in terms of hydrophobic and electrostatic interactions of various species present in the reaction systems. The addition of a counterion showed inhibitory effect on the reaction.
Abstract
The kinetics of the decolorization reactions of triphenylmethane dyes (BG, MG and PRH) with the cyanide ion (nucleophile) were studied in the presence of anionic micelles of sodium dodecyl sulfate (SDS). The reactions follow pseudo-first order kinetics. The rate constant depends on surfactant concentration. SDS micelles inhibit the overall rate of the reaction between the dye carbocation with the nucleophile. Quantitative analysis of the micellar data obtained has been done by applying a positive cooperativity model of enzyme catalysis. For all the dyes under study, the value of n (index of cooperativity) has been found to be greater than one. The inhibitory effect has been explained in terms of hydrophobic and electrostatic interactions of various species present in the reaction systems.
Zinc is essentially required for crop growth and its insufficient supply to the plants may severely limit the yield traits of a crop. A field experiment was performed during rabi season of 2009–10 and 2010–11 to evaluate the performance of different wheat genotypes under different levels of zinc namely 0 kg ZnSO4 ha−1, 20 kg ZnSO4 ha−1 and 20 kg ZnSO4 ha−1 along with foliar spray of 0.5% solution of ZnSO4. Genotypes responded positively in terms of tiller number, grain and biological yield, spikelet length, spikelet number, grain number and thousandgrain weight. The best response was observed with the application of 20 kg ZnSO4 ha−1 along with foliar spray of 0.5% solution of ZnSO4. Zinc application brought about a maximum increase of 58.6% in tiller number, 63.7% in thousand-grain weight, 40.5% in biological yield, 66.1% in grain yield irrespective of genotypes and the year of study. Wheat genotypes exhibited a variation in their performance which has been exploited in this study. Genotypes UP-262, PBW-175, PBW-343 were found to be superior for one or the other yield contributing factors.
Centella asiatica (L.) Urban (Apiaceae) possesses various healing effects and antioxidant properties. However, there has been very less focus on the investigation of chemotypic variations of C. asiatica found in different geographical zones of the country. In order to conserve C. asiatica, as it is an industrially valuable herb and overexploitation of this drug from wild is a common practice, different distinct accessions of C. asiatica from Nilgiri range (Deccan zones) of India were compared in relation to the levels of triterpenoid saponins. Physicochemical parameters were also evaluated in all the accessions. The metabolites investigated include madecassoside, asiaticoside, and its sapogenin, asiatic acid by high-performance thin-layer chromatography (HPTLC). CA-45 showed the highest content of asiaticoside, CA-51 showed the highest content of madecassoside, and CA-47 showed the highest content of asiatic acid among other accessions of Nilgiri range. It can be concluded that the geographical conditions (soil type and altitude) of these accessions are comparatively favorable for the production of higher levels of triterpenoid saponins in C. asiatica. The reported data will contribute to the establishment of knowledge about the triterpenoid saponin composition of different chemotypes of C. asiatica found in Nilgiri range of India in comparison to other geographical areas, and lays a foundation for the conservation and commercial cultivation of this plant.
