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101.
102.
JPC – Journal of Planar Chromatography – Modern TLC - A pilot study has been conducted to develop sample preparation procedure and TLC separation of radiolabeled metabolites of an AMPA... 相似文献
103.
Ž. K. Jaćimović V. M. Leovac G. Giester Z. D. Tomić Katalin Mészáros Szécsényi 《Journal of Thermal Analysis and Calorimetry》2007,90(2):549-555
In the
scope of design and optimise the equipment for alcoholic distillate beverages
production, a sufficient knowledge of physical properties and phase equilibria
is necessary. In this paper we present the temperature dependence of excess
molar volumes of the ternary system ethanol+water+1-propanol at the range
288.15–323.15 K and atmospheric pressure, due to the importance of the
1-propanol among the flavour compounds contained into this type of beverages.
Derived properties were computed due to its importance in the study of specific
molecular interactions. 相似文献
104.
Nickel(II) complexes of di-, tri- and tetra-peptides built up from Asp and/or Glu residues have been studied by potentiometric, UV–Vis and circular dichroism spectroscopic methods. The stoichiometry of the complexes are the same as in the case of common oligopeptides, but the presence of the side chain carboxylate groups results in differences in their stabilities and coordination modes. The presence of the β-carboxylate groups increases the metal binding affinity of the peptides in all cases. This is due to the coordination of the first, second and third aspartic acid residue in the case of the NiL, NiH−1L and NiH−2L complexes, respectively. The high negative charge of Asp4 suppresses the metal ion coordination of the third amide function, therefore the NiH−3L complex does not form with this tetra-peptide. In the case of peptides containing glutamic acid, no stability enhancement appears because there is only a weak interaction between the nickel(II) ion and the γ-carboxylate group, which is not able to compensate the disfavoured effect of the increasing negative charge of the complexes. 相似文献
105.
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108.
I. M. Szilágyi J. Madarász G. Pokol F. Hange G. Szalontai Katalin Varga-Josepovits A. L. Tóth 《Journal of Thermal Analysis and Calorimetry》2009,97(1):11-18
This paper discusses the changes in the structure and thermal reduction of nanosize hexagonal ammonium tungsten bronze (HATB),
(NH4)0.33−xWO3−y, which were caused by K+ ion exchange (doping) and studied by XRD, XPS, 1H-MAS NMR, FTIR, SEM and TG/DTA-MS. Comparison of the cell parameters of undoped and doped HATB revealed that both a and c cell parameters decreased after the ion exchange reaction, which showed that smaller K+ ions partly replaced the larger NH4+ ions in the hexagonal channels of HATB. After the reaction, from the hexagonal channels less NH3 evolved, which also supported the incorporation of K+ ions into the hexagonal channels. 相似文献
109.
Jacobsen NE Kövér KE Murataliev MB Feyereisen R Walker FA 《Magnetic resonance in chemistry : MRC》2006,44(4):467-474
The structure and stereochemistry of nine steroid metabolites isolated in quantities ranging from 0.15 to 1.8 mg were determined using a variety of NMR techniques, including heteronuclear multiple bond correlation (HMBC) using broadband adiabatic 13C pulses and phase-sensitive data presentation. Testosterone, androstenedione and progesterone were oxidized with housefly cytochrome P450 6A1 enzyme reconstituted in vitro with housefly NADPH cytochrome P450 reductase and cytochrome b5. NMR analysis in CD3OD using a modified HMBC sequence as well as 2D heteronuclear single quantum correlation (HSQC), COSY and nuclear Overhauser and exchange spectroscopy (NOESY), combined with a detailed analysis of J couplings showed that hydroxylation occurs exclusively on the beta-face of the steroids, at positions 2, 12, and 15. 相似文献