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  • Author or Editor: M. Zaidi x
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Abstract  

Extensive use of pan, by one-tenth of world"s population, entails the evaluation of trace element contents in its ingredients. Radiochemical neutron activation analysis (RNAA) was developed and successfully employed to determine the concentration of 36 trace elements (essential, toxic and nonessential) in its four basic ingredients, leaf of betel pepper, betel nut, catechu and lime. The radiochemical separation methodology has significantly improved the detection limits of most of these elements due to suppression of Compton background. This study provides the base-line values of certain toxic and essential elements in these ingredients. The daily intake of essential and toxic elements through pan was estimated and compared with the recommended values. The cumulative intake of Mn is four times higher than the recommended value and that of toxic elements is well below the tolerance limits.

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Abstract  

The proposed reference material from the International Atomic Energy Agency, namely IAEA-407 (Fish Homogenate) was analyzed using instrumental neutron activation analysis (INAA). 15 elements, Al, As, Cl, Co, Cr, Fe, Hg, Mg, Mn, K, Na, Sb, Se, V and Zn, were determined using two irradiations (5 minutes and 5 hours) and four countings. IAEA-MA-A-1/TM (Copepoda Homogenate), NIST-SRM-1566 (Oyster Tissue), NIST-SRM-1572 (Citrus Leaves) and NIST-SRM-1577a (Bovine Liver) were utilized as standards in the quantification step.

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Abstract  

Twenty-three individual food items commonly consumed in a high altitude region (Kashmir) have been investigated using instrumental neutron activation analysis. The concentration of Ca, Cl, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Se, Sn, and Zn is reported for these food articles. For quality assurance of our data, IAEA and NIST standard reference materials have also been studied. The dietary intake of these elements was calculated in accordance with the weekly food selection habits of the residents of this area. The dietary contribution of most of these elements was found to be in agreement to the RDA/ESadi levels. The purpose was to design a database of essential elements for this area and to study the adequacy levels of these elements in different dietary items. Fairly adequate intake of Ca, Co, Cr, Cu, Fe, Mg, Mn, Mo, Se, Sn, and Zn through these foodstuffs is reported, whereas, lower intakes through these items were found for Cl, K, and Na.

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Abstract  

Prostate specific antigen (PSA) is a reliable biochemical marker used in screening for prostate carcinoma. Immunoradiometric assays (IRMA) are generally used for the estimation of total/free PSA in serum samples. Radiolabeled antibody, an important reagent of IRMA was prepared and characterized using an in-house anti-PSA monoclonal antibody (Mab), Mab-2S. Mab-2S was radiolabeled with 125I and characterized for immunoreactivity and radiochemical purity. The usability of the radioiodinated Mab as tracer in IRMA was ascertained using authentic reagents for IRMA of PSA.

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Summary  

Spontaneous electrodeposition for the separation of electropositive metal ions is an attractive technique. This technique needs no external electromotive force. In this work, a spontaneous electrodeposition technique has been elaborated for the separation of carrier-free radioisotopes of palladium from neutron-irradiated cadmium targets. The deposited radioactive palladium was removed by dipping the platinum electrode in nitric acid giving a highly pure yield of carrier-free 109Pd and/or 103Pd. The separation factor achieved was reasonable (1.3 . 106). The process is very simple and needs little manipulation and amenable to automation and remote processing. The process is not sensitive to Cd(NO3)2 and HNO3 concentrations. Deposition velocity (4.119±0.353) . 10-2  min-1   and deposition constant 0.1211 cm . min -1 were calculated and from the temperature dependence of the deposition velocity constants, the activation energy (0.1155 ±0.3169 eV) was also determined. The thermodynamic spontaneity can be satisfied at different concentrations of Pd 2+ ions. The process was found to be irreversible.

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Selection on the basis of grain yield per se for improved performance under excessive moisture stress has often been misleading and considered inefficient. We assessed the importance of secondary traits of adaptive value under waterlogging stress. During the 2000–2004 summer-rainy seasons twelve trials were conducted and a total of 436 tropical/subtropical inbred lines (S 4 –S n ) were evaluated under excessive soil moisture stress. Excessive moisture treatment was applied at V 6–7 growth stage by flooding the experimental plots continuously for seven days. Different phenological and physiological parameters were recorded before, during and either immediately or 1–2 weeks after exposure to stress. Excessive moisture conditions significantly affected all the morphological and physiological traits studied. However, there was significant genetic variability for various traits, especially for root porosity and brace root development that were induced under excessive moisture. Across the trials, significant genetic correlations (p<0.01) was obtained between grain yield and different secondary traits, including ears per plant, root porosity, brace root fresh weight, number of nodes with brace roots and anthesis silking interval. Broad-sense heritability decreased under excessive moisture stress conditions for most of the traits; however, it increased significantly for root porosity, nodal root development and ears per plant. Our findings suggest that consideration of these second-ary traits during selection of maize germplasm for excessive moisture tolerance can improve selection efficiency and genetic gains.

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Abstract  

The thermal behavior of poly(methyl methacrylate) (PMMA) was studied in the presence of AlBr3 using TG-DTA-DTG, IR and Py-GC-MS techniques. Degradation products were identified. It was found that PMMA started degrading at a lower temperature due to the generation of free radicals (Br), being the product of decomposition of AlBr3. Despite early destabilization of the system, stabilization zone was also highlighted. Flammability test was conducted to check the affectivity of AlBr3. Degradation mechanism has been proposed. Pyrolysis of the system (PMMA–AlBr3) was also monitored by heating it at different temperatures.

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