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Summary

Two new structural variants of Marfey's reagent (1-fluoro-2,4-dinitrophenyl-5-l-alaninamide, FDNP-l-Ala-NH2) were synthesized by nucleophilic substitution of one fluorine atom in 1,5-difluoro-2,4-dinitrobenzene (DFDNB) by l-methioninamide or d-phenylglycinamide. The new variants FDNP-l-Met-NH2 and FDNP-d-Phg-NH2 were characterized and used for derivatization of twenty-six α-amino acids. The resulting diastereomeric derivatives were separated on a reversed-phase C18 HPLC column using a linear gradient of acetonitrile and aqueous trifluoroacetic acid (TFA) and the results were compared with those obtained by use of Marfey's reagent. To determine and establish the efficiency of both the new variants, separation results were compared for diastereomers of five representative amino acids (Ala, Phe, Ser, Asp, and Asn) prepared with MR, FDNP-l-Phe-NH2, FDNP-l-Val-NH2, FDNP-l-Leu-NH2, and FDNP-l-Pro-NH2, experiments being performed under identical conditions. Both the new chiral reagents enabled better separation of the diastereomers than Marfey's reagent for most of the amino acids. The reagent FDNP-d-Phg-NH2 enabled excellent separation for serine and asparagine whereas other reagents failed or provided poor results.

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Abstract  

Extraction behavior of137Cs was studied from nitric acid medium using dibenzo 18 crown 6 (DB18C6), 4,4'(5')di-acetylbenzo 18 crown 6 (DAB18C6), 4, 4'(5')di-hexanoylbenzo 18 crown 6 (DHB18C6), 4,4'(5')di-nonanoylbenzo 18 crown 6 (DNB18C6) and 4,4'(5')di-t-butylbenzo 18 crown 6 (DTBB18C6) in nitrobenzene medium. The stoichiometry of the species extracted with dibenzo 18 crown 6 (L) conformed to ML+. NO3 TheD Cs values were found not to be affected by the presence of aluminium nitrate in the aqueous phase. The separation behavior of fission products obtained from an irradiated natural uranium target was also studied. Presence of 0.004M phosphotungstic acid found to enhance theD Cs values at lower acidities.

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Abstract  

C.V. Raman is being acknowledged by worldwide physics community for his classic works. The present study has made an effort to analyze how much impact in number of citation receiving for his publications. Of course, there was a lack of tools for such a study some years back. The study has limited to the database Science Citation Index for the period 1982–2005. The noteworthy results are: One third of his research papers have been cited at least once; The research papers published during 1918–1940 could make remarkable impact; Three of his papers have shown an upward growth in number of citations receiving; The total citations to papers of age 46 and 54 as on the year 1982 accounted for more than 50 per cent of the total citations received; Research works in the ‘Acoustics’ area have been cited more than any other area of his works; Eponymal citations are to be explored and analysed to understand the real impact of his works.

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Abstract  

Ahmed Hassan Zewail, the Nobel laureate (1999) in chemistry have collaborated with 103 colleagues and has published 246 papers during 1976 to 1994 in: femtochemistry (62), reaction rates and IVR (56), general reviews (49), coherence and optical dephasing phenomena (27), solids: magnetic resonance and optical studies (13), liquids and biological systems (9), local modes in large molecules (9), molecular structure from rotational coherence (8), solar energy concentrators (7), and other studies (6). This authorship pattern included: three authored papers (87) followed by two authored (78), four authored (38), one authored (30), five authored (8), and six authored (5). Highest collaborations were with P. M. Felker (39), M. Dantus (19), and L. R. Khundkar (16). The core journals publishing his papers were: J. Chem. Phys. (77), Chem. Phys. Lett. (53), J. Phys. Chem. (33), and Nature(6) out of the 33 journal channels and 32 chapters in books.

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Abstract  

Guidelines for the assessment of internal doses from monitoring suggest default measurement of uncertainties (i.e. lognormal scattering factor, SF) to be used for different types of monitoring data. In this paper, SF values have been evaluated for internal contamination due to 60Co in two cases using whole body counting data. SF values of 1.04 and 1.03 were obtained for case I and II, respectively while SF value of 1.03 was obtained using bioassay data for case I. SF evaluated is in good agreement with the default values given by IDEAS guidelines. The present study also presents the follow up study of a case I of 60Co internal contamination using whole body counting and bioassay analysis. The effect of medical intervention applied on the subject is studied. Medical intervention of d-Penicillamine (250 mg × 4 daily) was orally administered from 13th day of initial exposure for about a fortnight, which showed reduction of activity present by 33.4% through urine.

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Summary  

The determination of atomic composition and thickness of zirconium oxide layers on zirconium based alloys is of practical interest in nuclear industry. This paper describes the application of backscattering spectrometry for the non-destructive determination of composition and thickness of zirconium oxide layers on autoclaved zircaloy coupons. The spectrometry used here is the Rutherford backscattering spectrometry (RBS) with 2.5 MeV α-particles, 3.05 MeV 16O(α,α)16O resonance scattering and 16O(p,p)16O elastic scattering with 2.5 MeV proton beam. Proton backscattering is found to be the most suitable technique for the overall compositional analysis of the layers whereas 3.05 MeV 16O(α,α)16O resonance scattering, for depth profiling of oxygen. The former technique is simple and provides rapid measurements. The lower stopping cross sections of protons and enhanced scattering cross section for oxygen over a wide range of proton energy enable the analysis of oxide layers of larger thicknesses. The thicknesses of these layers determined by backscattering are in good agreement with cross-sectional micrographs taken by scanning electron microscope (SEM).

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Abstract  

Sorption behavior of 241Am (~10−9 M) on naturally occurring mineral pyrite (particle size: ≤70 μm) has been studied under varying conditions of pH (2–11), and ionic strength (0.01–1.0 M (NaClO4)). The effects of humic acid (2 mg/L), other complexing anions (1 × 10−4 M CO3 2−, SO4 2−, C2O4 2− and PO4 3−), di- and trivalent metal ions (1 × 10−3 M Mg2+, Ca2+ and Nd3+) on sorption behavior of Am3+ at a fixed ionic strength (I = 0.10 M (NaClO4)) have been studied. The sorption of 241Am on pyrite increased with pH from 2.8 (84%) to 8.1 (97%). The sorption of 241Am decreased with ionic strength at low pH values (2 ≤ pH ≤ 4), but was insensitive in the pH range of 4–10, suggesting the formation of outer-sphere complexes on pyrite surface at lower pH, and inner-sphere complexes at higher pH values. The sorption of 241Am increased in the presence of (i) humic acid (5 < pH < 7.5), and (ii) C2O4 2− (2 < pH < 3). By contrast, other complexing anions such as (carbonate, phosphate, and sulphate) showed negligible influence on 241Am sorption. The presence of Mg2+, Ca2+ ions showed marginal effect on the sorption profile of 241Am; while the presence of Nd3+ ion suppressed its sorption significantly under the conditions of present study. The sorption of 241Am on pyrite decreased with increased temperature indicating an exothermic process.

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Optimum temperature and pH for the isolation of soy protein isolate (SPI) from soy protein concentrate (SPC) were established. Enzymatic hydrolysis of SPI with enzymes of different specificities such as trypsin, chymotrypsin, papain and urease was carried out and the products of hydrolysis were characterized by molecular mass determination [sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)] and thermal techniques [differential scanning calorimetry (DSC) and thermogravimetric analysis (TG)]. Enzymatic hydrolysis resulted in a significant reduction in molecular masses. However the thermal stability of hydrolysed SPI was similar to native SPI indicating that it is independent of molecular mass. DSC studies indicated an increase in temperatures of endothermic transition associated with SPI denaturation and loss of absorbed moisture in samples of lower molecular masses.

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Abstract

Bulk samples of Se92Te8−x Sn x glassy alloys are obtained by melt quenching technique. Differential scanning calorimetry (DSC) technique (under non-isothermal conditions) has been applied to determine the thermal properties of Se-rich glassy alloys at different heating rates. Results of glass transition temperature, enthalpy released, fragility and specific heat of Se92Te8−x Sn x (x = 0, 1, 2, 3, 4 and 5) chalcogenide glasses have been reported and discussed. The glass transition temperature (T g), activation energy of glass transition and fragility are found to increase with increase in Sn content. The glass transition temperature (by Gibbs–Dimarzio equation) also has been calculated. Both values of T g (experimental as well as theoretical) are found to be in good agreement at a heating rate of 10 K min−1. It has been observed that the value of specific heat (C p) below glass transition and difference in the value of C p before and after glass transition (ΔC p) is highly compositional dependent. The enthalpy release is related to the metastability of the glasses, and the least stable glasses are supposed to have maximum ΔH c.

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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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