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51.
The aim of this study was to characterize aqueous and alcoholic extracts [30%, 50% and 70% (w/v)] obtained from medicinal
herbs (Calendula officinalis, Hypericum perforatum, Galium verum, and Origanum vulgare) used in traditional medicine from our country. Samples were examined for total and individual content of phenolics and antioxidant
activities. The highest content of total polyphenols (9.9 ± 0.02 mg gallic acid equivalents (GAE) L–1 extract) and antioxidant activities expressed as Trolox Equivalent Antioxidant Capacity [307.51 TEAC mmol g–1DW by the ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) method and 20.90 TEAC mmol g–1 DW by the DPPH (1,1-diphenyl-2-picrylhydrazyl) method] was found in Origanum vulgare (50%) extract. Polyphenolic compounds were quantified using RP-HPLC. 相似文献
52.
Mikulásek L Grüner B Danila C Bohmer V Cáslavský J Selucký P 《Chemical communications (Cambridge, England)》2006,(38):4001-4003
The covalent attachment of two CMPO-functions and two anionic Cosan groups to the narrow rim of tert-butylcalix[4]arene leads to a dramatic increase of the extraction efficiency for the cone isomer; Am(3+) is removed from 5 x 10(-8) M solution to more than 99% by a single extraction step with a 3 x 10(-6) M solution of the calixarene. 相似文献
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Paola Pani Marco Signorelli Alberto Schiraldi Danila Torreggiani 《Journal of Thermal Analysis and Calorimetry》2010,102(1):391-390
Classical thermogravimetry and its modification with Knudsen cells were employed to quantitatively investigate the osmo-dehydration
of apple pulp samples. The data allowed realization of the complex mechanism of the process, which is not a mere solvent depletion,
since it also implies sugar exchanges between the apple tissue and the hypertonic syrup used to dehydrate the fruit. The comparison
between different hypertonic syrups, all at the same water activity, showed that maltose is more effective than either sucrose
or a mixture of sugars that mimics the saccharide content of the apple. The conclusions are supported by a thermodynamic analysis
of the aqueous solutions of these sugars at a concentration level as large as that of the hypertonic syrups used for the osmo-dehydration
process. 相似文献
55.
Sergio Abbate Danila Ghisletti Antonio Giorgilli Laure Lespade Giovanna Longhi 《Theoretical chemistry accounts》1993,87(3):215-232
Summary In this paper we use the Birkhoff-Gustavson perturbation theory to analyze the vibrational modes of two linearly coupled Morse oscillators in the transition region from normal modes to local modes. Our study is based on: truncation of the Hamiltonian written in normal mode coordinates at the 4th order, transformation to normal form and analytical study; construction and use of the approximate integrals of motion of the exact Hamiltonian according to Birkhoff and Gustavson theory. By comparison with a previous analytical study, we demonstrate that perturbation theory, based either on local or normal modes can be used to accurately describe transition modes. 相似文献
56.
V. M. Frolov O. P. Parenago L. P. Shuikina G. M. Cherkashin 《Reaction Kinetics and Catalysis Letters》1981,16(2-3):115-118
Complexes of PdCl2 with amines or pyridine reduced by (iso-Bu)2 AlH are shown to be catalytically active in the selective hydrogenation of conjugated dienes into olefins in aromatic media. The promoting effect of H2O and O2 has been established.
PdCl2 , (-Bu)2 AlH, . H2O O2.相似文献
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60.
V. V. Levenko Yu. F. Golovnev V. S. Cherkashin A. S. Komalov 《Russian Physics Journal》1974,17(5):667-671
A method is developed for producing single-crystal magnetic laminated films of ferrite-ferromagnetic composition based on chemical transport reactions. Certain magnetic properties of these films are investigated. It is established that the exchange interaction between the ferrite film and the ferromagnetic layer depends essentially on the thickness of the diffusion layer of the latter into the ferrite layer. This leads to almost simultaneous remagnetization of both films. It is postulated that the process of rotation of the magnetic moment in the direction of the external field begins in the ferrite film and passes smoothly first into the diffusion layer and then into the ferromagnetic film. Exchange coupling considerably decreases the coercive force of ferromagnetic layers grown on ferrite films.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 90–94, May, 1974. 相似文献