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21.
Mohácsi-Farkas Cs. Farkas J. Mészáros L. Reichart O. Andrássy É. 《Journal of Thermal Analysis and Calorimetry》1999,57(2):409-414
Thermal stability of vegetative cells of Listeria monocytogenes, Escherichia coli and Lactobacillus plantarum was studied by counting viable fractions and determining DSC curves of their suspensions. DSC curves in the 5–99°C range showed a series of endothermic transitions between 50 and 60°C, where the heat destruction of cells occurred. Heat denaturation of DNA required a higher temperature than cell killing. Thermal death was strongly influenced by the pH, composition and NaCl content of the suspending buffer. A mathematical model developed by us enabled comparison of DSC peak temperatures and temperatures required for loss of viability.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
22.
Using different reduction conditions Pd powders have been prepared and characterized by chemisorption and TPO (Temperature Programmed Oxidation) measurements. The amount of carbon deposits introduced during preparation seems to be peculiar to the preparation procedure. The O2 consumption curves attributed to PdO formation have shown two peak minima suggesting strong differences in the accessibility of Pd particles. 相似文献
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F. J. Reithel A. Farkas L. Farkas C. W. Sullens W. Rankin A. L. Olsen S. Kiyomizu G. F. Liebig Jr J. S. Mc Hargue E. B. Offutt P. R. Stout D. I. Arnon A. J. Bailey und S. Liotta 《Fresenius' Journal of Analytical Chemistry》1942,124(7-8):300-305
Ohne Zusammenfassung 相似文献
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Gy?rgy Székely Viktor Farkas László Párkányi Tünde Tóth Miklós Hollósi Péter Huszthy 《Structural chemistry》2010,21(1):277-282
This paper describes the structures of pseudo-18-crown-6 compounds (2, R,R-4 and 5) in the crystals together with theoretical calculations of the electronic circular dichroism (ECD) spectra. The achiral macrocyclic
phosphinic acid 5 forms hydrogen-bonded dimers in the crystal. The O1–O2 distance (2.489 Ǻ) indicates strong H-bondings. The conformations
of the macrorings of the achiral phosphinate 2 and the monomers of the achiral phosphinic acid 5 are chiral. A comparison of the torsion angles of the achiral methyl phosphinate 2 and the monomeric units of achiral 5 indicates a similar geometry. The torsion angles of the chiral methyl phosphinate (R,R)-4 differ more significantly from those in achiral methyl phosphinate 2. A negative 1Bb exciton couplet was observed in the ECD spectrum of monomeric (R,R)-6 in MeOH and H2O as in the spectra of (R,R)-4 in all solvents. To support the idea that (R,R)-4 has basically the same conformation in the crystal and in solution, the ECD spectrum of (R,R)-4 was calculated using the geometry of the molecule in the crystal. The calculated ECD spectrum shows a reasonable agreement
with the ECD spectra obtained in solution. This shows that the steric structure observed in the crystal is predominant in
solution as well. 相似文献
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Operator splitting methods for a special class of nonlinear partial differential equations with delay are investigated. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Lajos Kovács Pál Herczegh Gyula Batta István Farkas 《Journal of carbohydrate chemistry》2013,32(5):585-599
ABSTRACT The reactivity of the title compounds has been studied toward different nucleophiles and electrophiles. Unlike other ketene dithioacetals, compounds 3-5 did not add nucleophiles to the double bond. Instead, in the presence of Lewis acids they underwent substitution reaction at position 3. If the nucleophile was not strong enough, formation of 6 and 7 were observed. With 2,3,4,6-tetra-O-acetyl-1-thio-β-D-glucopyranose (18), a 3:1 mixture of 11 and 12 was formed from 4. These observations may be interpreted in terms of easy formation of the allylic carbocation I which gives diastereomers with nucleophiles. However, this allylic ether-like behaviour was ruled out by the fact that compounds 9 and 10 did not undergo [2,3] sigmatropic rearrangement with lithium diisopropylamide. With N-bromosuccinimide compound 3 gave the 2-bromo derivative 8. Compounds 3 and 8 resisted common mercury salt assisted demercaptalization procedures. 相似文献