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  • Author or Editor: G. Kaur x
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Shoots of ten day old seedlings of nineteen wheat genotypes were evaluated for proline metabolism, H2O2, thiobarbituric acid reactive substances (TBARS) and 2,2 diphenyl-picrylhydrazyl (DPPH) radical scavenging activity under water deficit, water withholding and salinity stress conditions. Principle component analysis demarcated four groups: i.e. drought tolerant (Excalibar, Krichauff, Babax, Drysdale, Gladius and C306), salt tolerant (Kharchia, Type11, Krl 1-4 and Krl 19), low stress tolerant (C273, C518 and C591) and susceptible (HD2967, PBW621, WH1105, HD3086, PBW660 and PBW175). Salt stress treatment affected the length, fresh weight and dry weight of seedlings of all studied genotypes in comparison to water deficit and water withholding condition which may be due to higher contents of TBARS. Shoots of salt and drought tolerant genotypes possessed higher proline content and DPPH radical scavenging activity alongwith reduced content of TBARS in parallel with decreased H2O2 content under water stress conditions. The activities of proline synthesizing enzymes i.e. pyrroline-5-carboxylate synthetase (P5CS) and pyrroline-5-carboxylate reductase (P5CR) were significantly higher than proline degrading enzyme viz. proline dehydrogenase (PDH) under water stress as compared to salinity stress conditions. Overall, results indicated that P5CS, P5CR and PDH activities led to higher build up of proline under water stress, which might play a significant role in improving membrane stability by increasing radical scavenging activity and finally imparting stress tolerance in specific wheat genotypes.

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Thermal behaviour of a number of organomercury(II) complexes of the type, p-XC6H4HgCl(L1) (I), p-XC6H4HgCl3(L2) (II), p-XC6H4HgL3 (III) and p-XC6H4HgL4 (IV) [L 1=isoniazid, L 2=theobromine, L 3=phenyldithiocarbamate, L 4=p-nitrophenyldithiocarbamate; X=Me, MeO, NO2] has been investigated. From TG curves, the order and activation energy of the thermal decomposition reaction have been elucidated. The variation of the activation energy has been correlated with the nature of the substituent on the phenyl ring. The heat of reaction has been elucidated from DSC or DTA studies. The fragmentation pattern has been analysed on the basis of mass spectra.

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Corn starch nanoparticles (SNPs) were prepared by ultrasonication of starch for 40 min at an amplitude of 40%, which modified some properties of starch so that it could be used as a functional ingredient in food products. The cereal SNPs were characterized on the basis of their morphology, particle size, crystallinity, pasting and functional properties. The SNPs were globular in shape as revealed by TEM. There was a decrease in the crystallanity of SNPs, whereas the functional properties were enhanced in SNPs as compared to raw starch. SNPs had a less paste viscosity as compared to raw starch. Salad dressing was prepared by using SNPs as a fat replacer. The prepared salad dressing was examined for colour, viscosity, and sensory attributes. Overall 60% of fat was replaced using corn SNPs without compromising its quality characteristics.

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The application of ultrasound during extraction of oil from apricot kernels using hexane was evaluated and compared with conventional methods (mechanical extraction and Soxhlet extraction). Results show that ultrasound assisted extraction (UAE) yields more oil with less solvent consumption. The oil yield from UAE, SE, and ME were 44.72%, 44.33%, and 35.06%, respectively. It is noteworthy that it took 44 min to extract oil by UAE method, while alike yield was obtained from SE in 6 hours. Oil extracted by UAE exhibited significantly higher peroxide and ester values. The functional groups of apricot kernel oil were analysed using Fourier transform infrared spectroscopy. Untreated and treated kernel powders were studied by scanning electron microscopy, and the development of microstructures and disruption of cell walls were evaluated. Our study suggests that ultrasound assisted extraction may be an effective method to extract edible oils by achieving higher efficiency in shorter extraction time.

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Thermal behaviour of a few lanthanide complexes of the type ML3(I) [M=Eu,Gd; HL=4,4,4-trifluoro- 1-(2-napthyl)-1,3-butanedione and EuL30.5dmm dmm=2,6-dimethylmorpholine(II)], has been investigated. From thermogravimetric(TG) curves, the decomposition pattern of the compounds has been analysed on the basis of mass loss data. The order and activation energy of the thermal decomposition reactions have been elucidated. From differential thermal analysis (DTA) studies, the heat of reaction and rate of thermal decomposition reaction have been enumerated.

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Six isomeric dimethyl anilinium bromides (DMABr) have been prepared and characterized by elemental and spectroscopic studies. Thermal decomposition of these salts has been studied by TG and simultaneous TG-DTA techniques. Kinetic parameters have been evaluated from isothermal TG data using contracting area and contracting cube equations. The decomposition pathways have also been suggested which involves simultaneous sublimation (at lower temperature) and dissociative vaporization/decomposition (at higher temperature).

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8-hydroxyquinoline (oxine) and uranyl acetate react in the solid state in 1∶3 stoichiometry to give UO2(C9H6NO)2·C9H6NOH. This reaction is diffusion controlled with an activation energy of 44.4 kJ mol−1. The reaction occurs by the surface migration of 8-hydroxyquinoline, which penetrates the product lattice to react with uranyl acetate. The isothermal decomposition of the solution phase product UO2Q2·HQ (Q=C9H6NO) obeys the Prout-Tompkins equation with an energy of activation of 53.3 kJ mol−1.

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Mass attenuation coefficients of amino acids viz. glycine (C2H5NO2), l-Serine (C3H7NO3), l-Theronine (C4H9NO3), l-Proline (C5H9NO2), l-Valine (C5H11NO2) and l-Phenylalanine (C9H11NO2) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by the gamma-ray transmission method in a narrow beam good geometry setup. Precisely measured densities of these solutions were used for the determination of these coefficients which varied systematically with the corresponding changes in the concentrations (g/cm3) of the solutions. Molar extinction coefficients of amino acids were then obtained at these energies and were found to be in good agreement with the theoretical results. In addition, total interaction cross sections of amino acids in aqueous solutions were also calculated.

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Three dimethylanilinium sulfates (DMAS) have been prepared and characterised by elemental and spectral studies. Thermal decomposition of these salts has been studied by TG and simultaneous TG-DTG technique and kinetic parameters were evaluated from both dynamic and isothermal TG data using mechanism based kinetic equations. The thermal decomposition pathways have also been suggested and it has been found that DMAS salts give dimethyl aminobenzenesulfonic acids (DMABSA) via solid state reaction. The primary step in the thermal decomposition involves proton transfer followed by sulfonation.

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