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Abstract  

We studied the production of nine typical organic analytical reagents labeled with11C,13N and18F by irradiation with charged particles and bremsstrahlung and the purification of labeled compounds with HPLC and sublimation. As a result, we found that six reagents, α-naphthol, β-naphthol, quinoline, α-nitroso-β-naphthol, 8-hydroxyquinoline, and 1,10-phenanthroline H2O could be labeled with11C by bombarding a mixture of each reagent and boron with protons. More than 10% of the11C was successfully exchanged with carbon atoms in the original reagents. We also found that sublimation is useful for purifying 8-hydroxyquinoline labeled with11C. The extraction property of11C-labeled 8-hydroxyquinoline between water and chloroform could be easily monitored by radioactivity measurement.

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Abstract  

C60 fullerene was radiolyzed in toluene solution both in presence of air and in vacuum at four different radiation doses 12, 24, 36, 48 and 96 kGy. Clear evidences of the addition of benzyl radicals to the fullerene cage derive from FT-IR and C13-NMR spectra of the reaction product. In presence of air the interference of oxygen is evident in the FT-IR spectra and from the elemental analysis. A detailed analysis of the kinetics of the multiple addition of benzyl radicals to the fullerene cage was made spectrophotometrically with the determination of the addition rate constants at the each addition step and the average number of benzyl groups added to the fullerene cage as function of the radiation dose.

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Free and bound aroma (precursors) compounds of the Muscat of Alexandria wines and the effect of skin contact (7 h, at 15 °C) on aroma composition have been investigated. The aroma compounds, extracted with the pentan-dichloromethane (2:1) method and Amberlite XAD-2 resin, were analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). A total of 41 free volatile compounds (12 esters, 8 acids, 7 terpenes, 5 alcohols, 4 phenols, 3 C-6 compounds, 2 carbonyl compounds) and 28 bound compounds (10 terpenes, 2 alcohols, 2 C-6 compounds, 5 fatty acids, 6 phenols, 2 C-13 norisoprenoids, 1 carbonyl compound) were identified in Muscat of Alexandria wines. Skin contact treatment increased the total free and bound aroma compound levels, and improved the wine quality by affecting the intensity as well as the quality of aroma.

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Abstract  

In kerosene samples from nuclear fuel reprocessing, iodoalkanes with chain-lengths from C4 to C13 have been identified. The kerosene samples were purified by means of solid-phase extraction. By this method other fission products like125Sb and106Ru were quantitatively removed from the solution. The only remaining radioactive nuclide was thus129I. The iodoorganic compounds in the kerosene from the solvent were enriched from 6000 Bq/L to 100 000 Bq/L129I by vacuum distillation. Chromatographic separation by HPLC, fractionation, and -measurement of the fractions showed that at least one polar and one nonpolar iodoorganic compound were present. Derivatisation of the iodoorganic compounds with, 1,4-diazabicyclo-2,2,2-octane to quatermary ammonium salts and252Cf plasma desorption mass spectrometry of the products revealed that the main iodoorganic constituents in the kerosene were iodobutane as polar and iodododecane as nonpolar compound in approximately equal concentrations.

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Abstract  

Four sulphato and nitrato complexes of cerium(IV),viz. (NH4)4Ce(SO4)4·2H2O (1), (NH4)2Ce(SO4)3 (2), (NH4)2Ce(NO3)6 (3) and Cs2Ce(NO3)6 (4) were studied by simultaneous TG/DTA under various experimental conditions in order to establish their decomposition mechanism and to compare the results with the literature data which have been reviewed. In the case of the ammonium compounds (1, 2 and3) the decompositions are accompanied by changes in the oxidation state of cerium; the presence of Ce(III) and Ce(IV) were studied byex situ magnetic susceptibility and XPS measurements. The crystal structure of (1) was determined as well. It forms monoclinic crystals with space groupP21/c; the parameters of the unit cell are:a=12.638(18) Å,b=11.362(10) Å,c=13.607(11) Å, β=110.17(9)°,V=1834.05 Å3.

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Abstract

There is little data on the mineralogy of carbonate pedofeatures in the calcareous soils in Hungary which belong to the European prairie ecodivision. The aim of the present study is to enrich these data.

The mineralogical composition of the carbonate pedofeatures from characteristic profiles of the calcareous soils in Hungary was studied by X-ray diffractometry, thermal analysis, SEM combined with microanalysis, and stable isotope determination.

Regarding carbonate minerals only aragonite, calcite (+ magnesian calcite) and dolomite (+proto-dolomite) were identified in carbonate grains, skeletons and pedofeatures.

The values relating, respectively, to stable isotope compositions (C13, O18) of carbonates in chernozems and in salt-affected soils were in the same range as those for recent soils (latter data reported earlier). There were no considerable differences between the values for the carbonate nodules and tubules from the same horizons, nor were there significant variations between the values of the same pedofeatures from different horizons (BC-C) of the same profile. Thus it can be assumed that there were no considerable changes in conditions of formation.

Tendencies were recognized in the changes of (i) carbonate mineral associations, (ii) the MgCO3 content of calcites, (iii) the corrected decomposition temperatures, and (iv) the activation energies of carbonate thermal decompositions among the various substance-regimes of soils.

Differences were found in substance-regimes types of soils rather than in soil types.

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Abstract  

A new co-crystal of theophylline and phthalic acid with 1:1 molar ratio has been prepared. It crystallises in the monoclinic crystal system, space group P21/c, a=11.5258(9), b=10.1405(6), c=13.9066(12) Å, β=106.827(4)°. The structure of the co-crystal has been revealed by single crystal X-ray diffraction. An infinite helical polymeric chain is formed by intermolecular hydrogen bonds of the two neutral constituents. The hydroxyl group and carbonyl oxygen atom in one of the carboxyl groups of phthalic acid form hydrogen bonds to O6 and to N(7)H atoms of theophylline, respectively, while the other carboxyl OH group of phthalic acid is in hydrogen bond to N9 atom of theophylline by very strong intermolecular interactions proven by 1883 cm−1 centred peak in FTIR spectrum. Thermal degradation of this new supramolecular compound is a two-step process in air. At first phthalic acid (47.4%) released up to 230°C, meanwhile it loses water and transforms into phthalic anhydride. In EGA-MS spectra, the characteristic fragments of water (m/z=17, 18) appear from about 180°C, while absorption bands of phthalic anhydride are shown in EGA-FTIR spectrum at about 210°C. In the second step theophylline begins to sublime, melts at 276°C, and then evaporates up to 315°C with minute residues.

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Nickel(II) complexes prepared from NNN type ligands and pseudohalogens

Synthesis, structure and thermal decomposition

Journal of Thermal Analysis and Calorimetry
Authors: F. Nazli Dınçer Kaya, Ingrid Svoboda, Orhan Atakol, Ümıt Ergun, Adnan Kenar, Musa Sari, and Kaan Emregül

Abstract  

Six nickel(II) complexes, using azide and thiocyanate ions, have been synthesized from bis-2,6(pyrazol-1-yl)pyridine (pp) and some methyl derivatives, 2-(3,5-dimethyl(pyrazol-1-yl)-6-(pyrazol-1-yl)pyridine (app) and bis-2,6(3,5-dimethyl(pyrazol-1-yl) pyridine (dmpp) in non-aqueous media. The complex structures were analyzed using elemental analysis, IR spectroscopy and thermogravimetry. Appropriate crystals of complex, containing azide [Nipp(N3)2]·MeOH (I) and thiocyanate [Nidmpp(SCN)2·MeOH] (VI) were prepared and the molecular structures determined using X-ray diffraction. Complex I was seen to be dinuclear as stated in literature, space group P21/n, monoclinic, a=10.503, b=10.681, c=13.291 Å, β=106.56° and Z=2 whereas complex VI was found to be mononuclear, space group P21/n, monoclinic, a=8.646, b=12.614, c=20.697 Å, β=97.18° and Z=2. The Ni(II) coordination in both complexes were octahedral. Thermogravimetric studies showed azide containing structures to resemble the characteristics of explosive materials. Coordinative MeOH were seen to leave the structure in thiocyanate containing complexes, followed by irregular degradation above 300°C.

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Abstract  

Stray neutron distribution in a medical cyclotron vault room was evaluated by neutron activation analysis (NAA). Neutrons were generated in the production of radioactive nuclides, such as 18F, 11C, 13N and 15O, for diagnostic usage. Indium foil was adopted to evaluate the stray fast and thermal neutron intensity based on 115In(nf, n′)115mIn and 115In(nth, γ)116m1In reactions, respectively. The indium foils were weighed, sealed and placed at 62 points around the 6.7×8.2 m2 cyclotron room. Additionally, each indium foil was exposed for over 80 minutes during cyclotron operation and γ-peaks were analyzed using an HPGe detector to evaluate the number of stray fast (Φ f) or thermal (Φ th) neutrons. The minimum to maximum numbers of fast and thermal neutrons were (3.47±0.11)×103 to (1.06±0.21)×104 n·cm−2·s−1 and 9 to 965 n·cm−2·s−1, respectively. The minimum detectable limit for stray neutrons was included herein to demonstrate the reliability. Accordingly, 60 and two points, respectively, the confidence level associated with the reported intensities of fast and thermal neutrons reached 95%. The low qualified ratio in the evaluation of stray thermal neutrons might have been caused by either the high Compton scattering plateau or the low intensity of the gamma-ray peak in the relevant spectrum.

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This study was conducted to develop a low cost method to preserve papaya (Carica papaya L.) pulp at ambient temperature with a combination of treatments including acid, heat, and cinnamon oil. Papaya pulp processed without and with 200 ppm cinnamon essential oil at pH 5.1, 81 °C, 7 min (ST2 and ST3); pH 3.9, 69 °C, 13 min (ST4 and ST5); and pH 4.5, 75 °C, 15 min (ST6 and ST7) was stored for 8 weeks at ambient temperature (28±2 °C). The cinnamaldehyde content of the papaya pulp treated with cinnamon oil decreased significantly during storage. ST5 and ST7 retained significantly higher β-carotene contents and lightness values compared to ST4 and ST6 during storage. The results indicated that acidification of papaya pulp to pH 4.5 and pasteurization at 75 °C for 15 min with 200 ppm cinnamon oil can be applied to obtain safe and high quality product, which is stable for 8 weeks at ambient temperature.

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