Microdetermination of steroid and triterpene saponin glycosides in various plant materials I. Allium species

Summary From plant material (Allium sativum, Allium cepa, Allium porrum), extracts characterised by a high haemolytic activity were obtained. In the raw saponin preparation the percentage of saponins in garlic, onion and leek was determined, applying the densitometric method on thin layer chromatograms, previously proposed⁵. Purified crystalline or oil-like saponin preparations were hydrolysed or complexed with cholesterol. The isolated sapogenins were identified by mass spectrometry, IR, NMR and UV analysis. The following sapogenins were found: sitosterol, gitogenin, oleanolic acid and amyrin.

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Mikrobestimmung von Steroid- und Triterpen-Saponinen in verschiedenem Pflanzenmaterial

Summary Aus Allium sativum, Allium cepa und Allium porrum wurden Extrakte erhalten, die stark hämolytisch wirken. Die rohen Saponin-Präparate wurden auf Dünnschicht-Platten mit unserer densitometrischen Methode untersucht und ihr Saponingehalt bestimmt. Die gereinigten, kristallisierten oder öligen Saponinpräparate wurden einer Hydrolyse und einer Komplexierung mit Cholesterin unterzogen. Die isolierten Sapogenine wurden massenspektrometrisch, mit IR, NMR und UV geprüft. Folgende Sapogenine wurden gefunden: Sitosterol, Gitogenin, Oleanolsäure und Amyrin.

     

The application of microbalance technique in study of the high temperature superconductors

Many physical-chemical properties of oxide superconductors depend on oxygen content and its distribution in the sample. Investigations of the thermal decomposition of the oxide superconductors in dynamic vacuum are valuable, particularly in view of the high oxygen diffusion coefficient in these cuprates. Dynamic vacuum protects against the readsorption of oxygen from the environment. Samples of the high-temperature superconductors were synthesised from stoichiometric mixtures of high-purity oxides and carbonates.The lattice parameters of all preparations were controlled, in both initial and final experiments using a Stadi P (Stoe) diffractometer with a positron-sensitive detector (CuK radiation). The oxygen content was measured by iodometric titration with a reproducibility of at least 0.02.DC four probe resistivity measurements were performed on pellets to which copper contacts were attached by using silver paint. Thermogravimetric analyses (TG) were performed by using a Cahn RG ultramicrobalance system.The purpose of the present paper is to show the application of microbalance technique in study of high-temperature superconductors.This revised version was published online in November 2005 with corrections to the Cover Date.     

Theoretical studies on the adsorption from non-ideal binary liquid mixtures on heterogeneous surfaces involving difference in molecular sizes of components

An equation for the phenomenon of competetive adsorption from binary liquid mixtures onto solids has been derived using the kinetic approach. In this equation the difference of the molecular sizes, the non-ideality of both bulk surface phases, and the energetic heterogeneity of the solid surface have been taken into account.

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Theoretische Untersuchungen zur Adsorption aus nichtidealen binären Lösungsmittelgemischen an heterogene Oberflächen fester Körper unter Berücksichtigung der Unterschiede in den molekularen Größen der Komponenten

Zusammenfassung Auf Grund kinetischer Erwägungen wurde eine Gleichung, die die Konkurrenzadsorption aus binären Lösungsmittelgemischen an den Oberflächen fester Körper beschreibt, aufgestellt. In der Gleichung wurde der Größenunterschied der Teilchen, die Nichtidealität der Lösung in der Volumen- und Oberflächenphase, sowie die energetische Heterogenität der Oberfläche des festen Körpers berücksichtigt.

     

Complexes of heavy lanthanides witho-aminobenzoic acid

Anthranilates of Tb-Lu prepared in the reaction of the rare earth hydroxides withortho-aminobenzoic acid (anthranilic acid) have the general formulaLn(C₆H₄NH₂COO)₃·2H₂O whereLn=Tb, Dy, Ho, Er, Tm, Yb, Lu. The water molecules in the hydrated compounds are in the outer coordination sphere. On heating in air at 493K dehydration occurs and the anhydrous anthranilatesLn(C₆H₄NH₂COO)₃ are formed. On the basis of the IR spectra it was found that the metal in dihydrated anthranilates was simultaneously coordinated through amino and carboxyl groups whereas in anhydrous anthranilates only through the bidentate carboxyl group. From X-ray analysis it was stated that the anthranilatesLn(C₆H₄NH₂COO)₃·2H₂O are isostructural, whereas the anhydrous compoundsLn(C₆H₄NH₂COO)₃ are isostructural in the two groups Tb-Er and Tm-Lu.

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Die Komplexe der schweren Selteneerdmetalle mit Orthoaminobenzoesäure

Zusammenfassung Zur Darstellung der Verbindungen des TypsLn(C₆H₄NH₂COO)₃·2H₂O (mitLn=Tb bis Lu) wurde die berechnete Menge vonLn(OH)₃ und C₆H₄NH₂COOH-Lösung gemischt und bei 363K schnell zur Kristallisation gebracht. Die Produkte werden schnell abfiltriert, mit Wasser gewaschen und bis zur Gewichtskonstanz getrocknet. Die VerbindungenLn(C₆H₄NH₂COO)₃·2H₂O sind isostrukturell mit der Dichte ungefähr 1.6g·cm^–1 und geringer Löslichkeit in Wasser bei Raumtemperatur. Beim Erhitzen folgt zunächst Entwässerung bei 493 K, später Zersetzung zu Tb₄O₇ undLn ₂O₃. Die wasserfreien VerbindungenLn(C₆H₄NH₂COO)₃ sind isostrukturell in 2 Strukturtypen: Tb-Er and Tm-Lu. Die Infrarotspektren von wasserfreien Verbindungen und Doppelhydraten wurden registriert. Es wurde festgestellt, daß die Koordinierung der Seltenerdmetalle mit Liganden in den Dihydraten sowohl durch die Amino- als auch durch Carboxylgruppen erfolgt. In den wasserfreien Komplexen tritt die Koordinierung nur durch Carboxylgruppen auf.

     

Pertraction of Penicillin G in Hollow Fiber Contained Liquid Membranes

Pertraction of Penicillin G in Hollow Fiber Contained Liquid Membranes was investigated in a system consisting of 2 Liqui Cel 106 modules from Hoechst Celanese. The flux of Pen G depended upon the content of n-octanol and of Amberlite LA2 in kerosene used as a membrane phase. During the pertraction of Pen G in HFCLM system the pH difference between the both buffered aqueous phases diminished proportionally to the contact time with the membrane phase. The flux of citric acid used as a buffer component in the feed phase attained 11.8 mM/m²·h and was comparable with the flux of Pen G equal to 18.4 mM/m²·h. In order to eliminate the undesired transport of citric acid, CO₂ was used as a volatile buffer component. Although the pH values were stabilised in the range of 5.47 and 7.45 in the feed and strip phase, respectively, the achieved Pen G flux was significantly lower.     

Molecular motions in chloramphenicol studied by35Cl nuclear quadrupole and1H nuclear magnetic resonance spectroscopy

The³⁵Cl nuclear quadrupole resonance (NQR) frequency (v_Q), nuclear quadrupole spinlattice relaxation time (T_1Q),¹H nuclear magnetic resonance second moment (M₂) and nuclear magnetic spin-lattice relaxation timeT ₁) were measured for polycrystalline chloramphenicol (drug) as a function of temperature. Hindered rotation of the CHC1₂ group and the phenyl ring was detected, the relevant activation energies were determined. The rotations are discussed in detail.     

Solid Solutions in The Cr2O3–α-Sb2O4–MoO3 System

DTA and XRD methods used to examine the Cr₂O₃–α-Sb₂O₄–MoO₃ system have shown that a substitution solid solution of MoO₃ in CrSbO₄ is formed. A study of all the theoretically possible solid solution models has pointed to the fact that Mo⁶⁺ ions are incorporated into the CrSbO₄ crystal lattice, in the place of Sb⁵⁺ ions and the compensation of redundant charges takes place through cation vacancies arising in an Sb⁵⁺ sub-lattice. The solubility limit for MoO₃ in CrSbO₄ does not exceed 25.00 mol%. CrSbO_4(s.s.) is stable to ~1320°C. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase Equilibria in the System V9Mo6O40-AlVMoO7

DTA and XRD methods were applied in studies on phase equilibria established in the system V₉Mo₆O₄₀-AlVMoO₇ up to 1000°C over the whole component concentration range. The results were presented in the form of a phase diagram. This revised version was published online in August 2006 with corrections to the Cover Date.     

Rapid and sensitive RP-LC method with amperometric detection for pharmacokinetic assessment of propafenone in human serum of healthy volunteers

A rapid and sensitive liquid chromatography method with amperometric detection has been developed for the determination of propafenone in serum. Sample preparation based on single extraction with dichloromethane using bupivacaine hydrochloride as internal standard. The compounds were separated on C-18 reversed-phase analytical column with the mobile phase composed of methanol-acetonitrile-10 mM K₂HPO₄ (45: 25: 30, v/v/v). Analytes were detected electrochemically with the use of amperometric detector. The quantification limit for propafenone in serum was 10 ng/mL. Linearity of the method was confirmed in the range of 10–500 ng/mL with correlation coefficient of 0.9998. Inter-day relative standard deviations (RSD) ranged from 0.27 to 11.9% and intra-day RSD equalled from 1.1 to 9.7%. The newly developed method was applied for the monitoring of the drug in blood levels with 18 healthy volunteers taking tablet with propafenone.     

Linear and nonlinear properties of photonic crystal fibers filled with nematic liquid crystals

We investigate linear and nonlinear light propagation in the photonic crystal fibers infiltrated with nematic liquid crystals. Such a photonic structure, with periodic modulation of refractive index, which could be additionally controlled by the temperature and by the optical power, allows for the study of discrete optical phenomena. Our theoretical investigations, carried out with the near infrared wavelength of 830 nm, for both focusing and defocusing Kerr-type nonlinearity, show the possibility of the transverse light localization, which can result in the discrete soliton generation. In addition, we present the preliminary experimental results on the linear light propagation in the photonic crystal fiber with the glycerin-water solution and 6CHBT nematics, as the guest materials.