Separation and quantification of inulin in selected artichoke (Cynara scolymus L.) cultivars and dandelion (Taraxacum officinale WEB. ex WIGG.) roots by high-performance anion exchange chromatography with pulsed amperometric detection

The profile of fructooligosaccharides and fructopolysaccharides in artichoke heads and dandelion roots was investigated. For this purpose, a suitable method for high-performance anion exchange chromatography with pulsed amperometic detection was developed. The separation of monomers, oligomers and polymers up to a chain length of 79 sugar residues was achieved in one single run. Glucose, fructose, sucrose and individual fructooligosaccharides (kestose, nystose, fructofuranosylnystose) were quantified in six different artichoke cultivars and in dandelion roots. The contents ranged from 12.9 g/kg DM to 71.7 g/kg DM for glucose, from 15.8 g/kg DM to 67.2 g/kg DM for fructose, and from 16.8 g/kg DM to 55.2 g/kg DM for sucrose in the artichoke heads. Kestose was the predominant fructooligosaccharide, followed by nystose and fructofuranosylnystose. In four cultivars fructofuranosylnystose was only detectable in traces and reached its maximum value of 3.6 g/kg DM in the cultivar Le Castel. Furthermore, an average degree of polymerization of 5.3 to 16.7 was calculated for the individual artichoke cultivars, which is noticeably lower than hitherto reported. In contrast, the contents of kestose, nystose and fructofuranosylnystose in dandelion root exceeded that of artichoke, reflecting the short chain characteristic of the inulin, which was confirmed by chromatographic analysis.     

Similarities and Differences between Crystal and Enzyme Environmental Effects on the Electron Density of Drug Molecules

The crystal interaction density is generally assumed to be a suitable measure of the polarization of a low-molecular weight ligand inside an enzyme, but this approximation has seldomly been tested and has never been quantified before. In this study, we compare the crystal interaction density and the interaction electrostatic potential for a model compound of loxistatin acid (E64c) with those inside cathepsin B, in solution, and in vacuum. We apply QM/MM calculations and experimental quantum crystallography to show that the crystal interaction density is indeed very similar to the enzyme interaction density. Less than 0.1 e are shifted between these two environments in total. However, this difference has non-negligible consequences for derived properties.     

Zur Kenntnis von Harzbestandteilen

Ohne ZusammenfassungDa keine Gewähr für die Einheitlichkeit dieser Substanz gegeben ist, wird von der Aufstellung einer Formel abgesehen.     

Introducing Crystalline Graded Algebras

We develop a generalization of the traditional crossed products and we derive general structural properties. Localization at a particular Ore set is investigated and as a consequence the relation to crossed products is examined. Finally, examples are given. Presented by Alain Verschoren.     

Microanalysis of perfluoro compounds

Summary Because of the extremely high thermal and chemical stability of perfluoro organic compounds, special methods of analysis are required for carbon, hydrogen and fluorine. Sulfur, phosphorus, and halogens can be determined by conventionalCarius digestion and subsequent gravimetric methods. Nitrogen is determined by theDumas method. Oxygen cannot be determined by the usualUnterzaucher method.Carbon and hydrogen are determined by combustion in oxygen with a tube filling consisting of (Ag; 3 MgO · Al₂O₃; Ag) at 950° C; (Ag; Pb₂O₃) at 450° C; (Ag;PbO₂;Ag) at 180° C. The sample burner is operated at 950° to 1000° C.Fluorine is determined by reaction with sodium in a conventional sodium peroxide bomb with lead or copper gasket. The lower part of the bomb is held at red heat with a torch for about 20 seconds. The sodium fluoride from the reaction is titrated with thorium nitrate.

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Zusammenfassung Für die Bestimmung von Kohlenstoff, Wasserstoff und Fluor in organischen perfluorierten Verbindungen sind wegen deren außerordentlich hoher thermischer und chemischer Stabilität spezielle analytische Methoden notwendig. Schwefel, Phosphor und die Halogene können nachCarius bzw. mit den üblichen gravimetrischen Methoden bestimmt werden. Sauerstoff kann nicht nach derUnterzaucher- Methode bestimmt werden.Kohlenstoff und Wasserstoff sind bestimmbar bei Verbrennung mit einer Rohrfüllung aus (Ag; 3 MgO · Al₂O₃; Ag) bei 900°; (Ag; Pb₂O₃) bei 450°: (Ag; PbO₂; Ag) bei 180°. Der bewegliche Brenner wird auf einer Temperatur von 950° bis 1000° gehalten.Fluor kann durch Umsetzung mit Natrium in einer gewöhnlichen Peroxyd-Bombe mit Blei- oder Kupfer-Dichtung bestimmt werden. Der untere Teil der Bombe wird mit einem Gebläse für 20 Sekunden auf Rotglut erhitzt. Das gebildete Natriumfluorid wird in der gewöhnlichen Weise mit Thoriumnitrat titriert.

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Résumé La grande stabilité thermique et chimique des composés organiques perfluorés impose l'emploi de méthodes spéciales pour le dosage du carbone, de l'hydrogène et du fluor. Il est possible de déterminer le soufre, le phosphore, et les halogènes par digestion classique deCarius suivie d'un dosage gravimétrique approprié. L'azote est dosé par la méthode deDumas; quant à l'oxygène, il ne peut être déterminé par la méthode habituelle deUnterzaucher.Le carbone et l'hydrogène sont déterminés par combustion dans l'oxygène à l'intérieur d'un tube comportant un remplissage constitué par (Ag; 3 MgO · Al₂O₃; Ag) à 950°, (Ag; Pb₂O₃) à 450° (Ag; PbO₂; Ag) à 180° C. Le brûleur mobile permet d'obtenir une température de 950 à 1000° C.Le fluor est dosé après minéralisation par le sodium dans une bombe courante à peroxyde de sodium, comportant un joint de plomb ou de cuivre. La partie inférieure de la bombe est portée au rouge à l'aide d'un chalumeau pendant environ 20 secondes. Le fluorure de sodium obtenu est titré à l'aide de nitrate de thorium.

     

Effect of K(+) on the Stoichiometry of Carbonated Hydroxyapatite Obtained by the Hydrolysis of Monetite

This study investigates the stoichiometry and the thermal stability of K(+)- and CO(3)(2)(-)-containing apatites (KCAp's) obtained by the hydrolysis of monetite. The analysis results of the samples after drying reveal that the KCAp's start to lose carbonate at temperatures V(Ca) + CO(3)(2)(-) + V(OH)] and [Ca(2+) + PO(4)(3)(-) <--> K(+) + CO(3)(2)(-)], where V(X) stands for a vacancy in the X-sublattice. Moreover, a small part of the CO(3)(2)(-) ions are presumably incorporated according to [Ca(2+) + 2PO(4)(3)(-) <--> V(Ca) + 2CO(3)(2)(-)]. A comparison of the contributions of these fundamental mechanisms with the results for precipitated Na(+)- and CO(3)(2)(-)-containing apatites shows that no intrinsic coupling whatsoever exists between these mechanisms.     

Multiple phase-shifted interferograms obtained from a single interferogram with linear carrier

In this paper we propose a new method for phase retrieval in an interferogram with a spatial linear carrier. We demonstrate that from the primary interferogram one can extract multiple interferograms (with lower resolution than the original one) with arbitrary phase-shift amounts between them. Then, by applying well-known phase-shifting algorithms, from these phase-shifted interferograms the phase can be retrieved. The method does not require sophisticated data-processing and is computationally efficient. Numerical simulations and validation experiments are presented.