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  • Author or Editor: P. Kumar x
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Abstract  

Water samples collected from various sources along the south-west coastal region of India have been analyzed for trace uranium concentration. Fission track registration technique with the Dry method has been used for the analysis. Uranium concentration was found to vary from 0.28±0.01 g/l to 2.71±0.41 g/l and was higher in sea water than in well, river and tap water, respectively.

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A rapid and high resolution separation of lanthanides by HPLC technique has been developed using Di-(2-ethylhexyl) phosphoric acid (HDEHP) coated reverse phase column and a-hydroxy isobutyric acid as the complexing reagent for elution. A gradient elution technique has been developed for achieving the separation of the entire lanthanide series. Isocratic elution procedure has also been developed for the separation of lighter (La to Gd) as well heavier lanthanides (Lu to Tb). This paper describes the separation methods developed and their application for the determination of lanthanides in a fission product mixture.

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The present work describes the application of radiotracer technique for studying uptake of arsenic on titanium hydroxide, commercial titanium dioxide (TiO2) powder (anatase) and synthesized mesoporous titania beads in acidic, neutral, and alkaline conditions. Sol–gel templating method was used to prepare titania–polysaccharide composites, with different polymer contents. Mesoporous titania was obtained by heat treatment of the composite beads in a controlled environment. The synthesis process was optimized, using thermogravimetry analysis. X-ray diffraction patterns confirmed the formation of anatase pure phase titania (TiO2) at 700 °C in different environments, and scanning electron microscopy studies confirmed uniform pore size distribution. The effect of surface area, polymer content and pH on uptake of arsenic(III) and (V) on the synthesized titania beads was also investigated. Arsenic(V) was found to be retained quantitatively on the titania beads synthesized from 0.8% polymer content titania–polymer composite precursor in neutral to alkaline conditions. Details of the results obtained are discussed.

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Abstract  

Labile pool (E-value) of Mn and extractable soil Mn content using six multinutrient extractants were estimated in fifty surface (0–15 cm) soil samples. Labile pool of Mn was poorly correlated to the general soil properties and modified Olsen’s-; 0.01 M CaCl2- and 1 M MgCl2-extractable Mn contents but it was positively and significantly correlated to diethylene triamine pentaacetic acid (DTPA), pH 7.3; ammonium bicarbonate + DTPA (pH 7.6); and Mehlich-3-extractable soil Mn contents. The multinutrient extractants involving only simple salt solutions were not useful to assess the availability of Mn in soils.

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Summary  

Sorption of inorganic mercury (Hg2+) and methyl mercury, on chemically synthesized polyaniline, in 0.1-10N HCl solutions has been studied. Hg2+ is strongly sorbed at low acidities and the extent of sorption decreases with increase in acidity. The sorption of methyl mercury is very low in the HCl concentration range studied. Sorption of Hg2+ on polyaniline in 0.1-10N LiCl and H2SO4 solutions has also been studied. The analysis of the data indicates that the sorption of Hg2+ depends on the degree of protonation of polyaniline and the nature of mercury(II) chloride complexes in solution. X-ray photoelectron spectroscopy analysis (XPS) of polyaniline sorbed with mercury show that mercury is bound as Hg2+. Sorbed mercury is quantitatively eluted from polyaniline with 0.5N HNO3. Polyaniline can be used for separation and pre-concentration of inorganic mercury from aqueous samples.

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Bowman-Birk inhibitor (BBI) is a protease inhibitor that affects protein digestibility; however, it is increasingly being recognised as anutraceutical and cosmeceutical molecule. In the present study, BBI concentration during soybean seed development, its loss during processing treatments, and the level in commercial soy products were determined. Significant differences for BBI concentration were observed across the genotypes and seed development stages. Genotype × seed development stage interaction was also found to be significant (P<0.05) for BBI concentration. Boiling, autoclaving, microwave irradiation, and sprouting resulted in significant (P<0.05) loss of BBI. Minimum loss was observed in sprouting, while autoclaving for 5 min completely deactivated BBI. Microwave irradiation of the soaked seeds resulted in higher BBI loss than of dry seeds. Among the commercial soy products, BBI concentration was high in soy flour brands, minuscule in ready-to-cook miso soup and undetectable in extruded soy products and roasted soy nuts.

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Abstract  

Drinking water samples were collected from four different districts, namely Bhatinda, Mansa, Faridkot and Firozpur, of Punjab for ascertaining the U(nat.) concentrations. All samples were preserved, processed and analyzed by laser fluorimetry (LF). To ensure accuracy of the data obtained by LF, few samples (10 nos) from each district were analyzed by alpha spectrometry as well as by fission track analysis (FTA) technique. For FTA technique few μl of water sample was transferred to polythene tube, lexan detector was immersed in it and the other end of the tube was also heat-sealed. Two samples and one uranium standard were irradiated in DHRUVA reactor. Irradiated detectors were chemically etched and tracks counted using an optical microscope. Uranium concentrations in samples ranged from 3.2 to 60.5 ppb and were comparable with those observed by LF.

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A new molybdenum(VI) complex Cs2(NH4)2[Mo3O8(C2O4)3] (CAMO) has been prepared and characterized by chemical analysis and IR spectral studies. Thermal decomposition studies have been made using TG, DTA and DTG techniques. The compound is anhydrous and stable up to 160°C. Thereafter it decomposes in three stages. The first and the second stages occur in the temperature ranges 160–220°C and 220–280°C to give the intermediate compounds having the tentative compositions Cs4(NH4)2[Mo6O16(C2O4)3(CO3)2] and Cs4[Mo6O16(C2O4)2(CO3)2] respectively, the later then decomposing to give the end product Cs2Mo3O10 at 370°C. The end product was characterized by chemical analysis, IR spectral and X-ray studies.

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Abstract

12-Molybdophosphoric acid (MPA) supported on V2O5 dispersed γ-Al2O3 catalysts with different loadings were prepared and characterized by BET surface area, X-ray diffraction, FT-infrared, laser Raman, X-ray photoelectron spectroscopy and temperature programmed reduction techniques. The catalytic activities were evaluated for the aerobic oxidation of benzyl alcohol. The conversion of benzyl alcohol increased with the amount of MPA content and the catalyst with 15 wt% of MPA showed highest activity. The synergistic effect of V2O5 and MPA was observed for the oxidation of benzyl alcohol compared to MPA on alumina without V2O5. The XPS results suggest the participation of both Mo and V in the reaction as the used catalysts showed the reduced oxidation states of both Mo and V. The high selectivity of the catalysts is due to the presence of V2O5, which induces the redox nature to the catalyst and also preventing the decomposition of MPA on Al2O3.

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Indiscriminate use of antibiotics in apicultural practices may lead to contamination of otherwise healthy and naturally produced honey. Contamination not only affects honey quality but also pose significant health risks to consumers. In this context, one hundred raw honey samples from India were analysed for presence of antibiotic residues. For determination of oxytetracycline and erythromycin, high performance liquid chromatography and for chloramphenicol, enzyme immunoassay based validated procedures were used. Oxytetracycline and erythromycin with concentrations above maximum tolerance limits were detected in 24% and 2% samples, respectively. None of the samples contained chloramphenicol residues. Although, total dietary intake of detected antibiotics through honey was found to be <1% of their acceptable daily intake values, the presence of antibiotics in honey is an alarming health concern for people following customary honey feeding. The outcomes underline the need of inter-sectoral approaches to create awareness among beekeepers regarding health risks associated with residues of antibiotics in honey and merits of approved apicultural practices. Therefore, to meet global food safety requirements, continual residue monitoring schemes along with enlightenment of beekeepers on scientific beehive management and risks associated with incautious apicultural practices are of vital importance.

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