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- Author or Editor: A. Sood x
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Abstract
Results of recent IAEA activities related to assembly, maintenance and verification of databases of relevance to radiochemistry are presented. These include: (1) integral and differential nuclear constants for prompt gamma neutron activation analysis; (2) excitation functions for cyclotron production of medical radioisotopes using proton, deuteron and alpha particle projectiles; (3) data for dose calculations in radiation medical treatment/diagnosis and (4) nuclear cross section standards.
Photolysis of anhydrous NiN6 at 30° under the action of high pressure Hg arc is reported. The sample for photolysis studies is prepared by treating aqueous nickel azide solution with excess of AnalaR dimethyl ketone. The pressure of N developed during photolysis under steady state conditions at constant intensity is a linear function oft 1/2 and dark rate analysis suggests that the dependence ont 1/2 should be due to the diffusion of N from reaction site to the surface of solid azide. Absence of photoconduction in the wavelength range of the irradiating radiation suggests that excitons are the reactive species and the linear dependence of the rate of photolysis on intensity is interpreted in terms of the reaction of a trapped exciton with adjacent azide ion.
Prolonged incubation of Azolla pinnata in phosphorus deficient medium resulted in the highest relative growth on 4th day but it ceased after 12th day. There was a decrease in heterocyst frequency of Anabaena azollae (endosymbiont) with prolonged incubation in such medium. The cyanobiont did not differentiate akinetes during the course of 16-days of incubation. Anthocyanin content and total proteins dropped in phosphorus starved Azolla plants. However, tissue phosphorus increased up to 8th day and decreased thereafter. Activity of acid and alkaline phosphatases elevated up to 12th day and declined afterward in phosphorus deprived Azolla. This investigation clearly reflected that Azolla pinnata sustained its growth and metabolic activities in -P conditions during early period of growth (up to 8th day) and further prolongation of phosphorus starvation resulted in appearance of phosphorus deficiency symptoms that can act as indicators of phosphorus deficiency in the water fern, Azolla pinnata.
Abstract
The thermal decomposition of the complexes [Vcl (acac)2(OAr)] (where acac=2,4-pentanedionato anion; OAr=–OC6H4O-M-4, OC6H4OBut-4) has been studied using non-isothermal techniques (DTA and TG). The TGA indicate that the substitution of chlorine in VCl2(acac)2 with aryloxide ligands results in an increase in the initial temperature of decomposition (IDT) of the new complexes. The role of the substituent at the aryloxide ring on the thermal stability of the complexes is depicted and hence described. The ultimate decomposition product in all the complexes has been identified as V2O5. The kinetic and thermodynamic parameters namely, the energy of activation E, the frequency factor A, entropy of activation S and specific reaction rate constant k r etc. have been rationalized in relation to the bonding aspect of the aryloxide ligands.
The pigment accumulating potential of two strains of Anabaena was evaluated in the presence of various sugars (glucose, sucrose and jaggery), when incubated under light/darkness. Both strains exhibited excellent potential for phycocyanin (PC), phycoerythrin (PE) and total phycobiliproteins (PBS) production in light, in the presence of sugars. In terms of accumulation of % phycobiliproteins / proteins, Anabaena cylindrica (ATCC 29414) was observed to be more responsive to jaggery while sucrose and glucose were more stimulatory for Anabaena sp. (cyanobiont isolated from Azolla mexicana ). Significant enhancement in PC and PE content by supplementation with sugars emphasises the need for in-depth analysis of the interactions between assimilation of sugars and pigment production pathways in cyanobacteria.
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. Spirulina, Dunaliella 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.
The present research endeavor was undertaken to depict the response of different generations viz., F1, F2, BC1F1, BC1F2, BC1F3, BC1F4 and BC1F5 of triticale × wheat and wheat × rye hybrids towards the different parameters of haploid induction. The experimental material included the different generations obtained utilizing five genotypes of triticale (DT-123, DT-126, TL-2900, TL-2908 and TL-9335), four genotypes of Himalayan rye (Karoki rye, shanoor rye, tino rye and triloki rye) with various elite bread wheat genotypes as parents in wide hybridization programme. The triticale × wheat and wheat × rye recombinants were further subjected to Imperata cylindrica-mediated chromosome elimination approach of doubled haploidy breeding. The variability in the haploid induction parameters was observed to be under genetic control for embryo formation and regeneration, while pseudoseed formation was only affected by auxin treatment. Among the different generations, the backcross generations viz., BC1F1 and BC1F2 were found to exhibit significant positive response towards haploid induction parameters in both triticale × wheat and wheat × rye hybridization. Knowledge of effective generation for haploid induction in triticale × wheat and wheat × rye hybridization not only saved the time and energy but also enhanced the efficiency of haploid induction.
Abstract
A review of our work on the application of the PGNAA method as applied to five industrial applications is given. Some introductory material is first given on the importance and use of Monte Carlo simulation in this area, some comments on the place of PGNAA in elemental analysis, and a brief description of the Monte Carlo — Library Least-Squares (MCLLS) approach to the nonlinear inverse PGNAA analysis problem. Then the applications of PGNAA are discussed for: (1) on-line bulk coal analysis, (2) nuclear oil well logging, (3) vitrified waste, (4) the analysis of sodium and aluminum in “green liquor” in the presence of chlorine, and (5) the conveyor belt sorting of aluminum alloy samples. It is concluded that PGNAA is a rapidly emerging important new technology and measurement approach.
