Determination of diamine oxidase by a kinetic method with 2,2''-azino-di(3-ethylbenzthiazoline-6-sulfonate)

Hydrogen peroxide, the product of diamine oxidase-catalyzed putrescine or cadaverine oxidation, formed in proportion to the enzyme activity, is measured spectrophotometrically by using the above sulfonate (ABTS) and peroxidase. Only one reagent solution containing 3 mmol of putrescine or 10 mmol of cadaverine, 4 mmol of ABTS and 3000 U of peroxidase per litre of 0.2 mol l^-1 Tris—0.1 mol l^-1 HCl buffer pH 7.5 is needed. Absorbance changes are measured at 410 nm over the first 3 min of the reaction. This initial oxidation rate of the chromogen enables diamine oxidase activity up to 230 U l^-1 to be determined.     

Zur Entwicklung analytischer Methoden am Beispiel der Elemente Selen und Tellur

Zusammenfassung Anhand von Literaturrecherchen aus den Chemical Abstracts der Jahre 1970–1975, ausgewertet nach dem Stichwort Analyse von Selen und Tellur der CID, Berlin, wird die Entwicklung der Analyse der genannten Elemente nach methodischen und nationalen Gesichtspunkten statistisch ausgewertet. Es zeigt sich eine Zunahme der Atomabsorptionsspektroskopie (AAS) und der Röntgenfluorescenzanalyse (RFA), dagegen eine Abnahme photometrischer und fluorimetrischer Methoden. Die jährliche Gesamtzahl der Publikationen auf diesem Gebiet bleibt in dem untersuchten Zeitraum konstant.Wir danken herzlich der Alexander von Humboldt-Stiftung für die Gewährung eines Stipendiums (L. F.). Unser Dank gilt ferner Frau Mischevsska für ihre technische Unterstützung.     

Thermal Properties Of ZrTe5

High resolution specific heat measurements have been performed in the temperature range 60-190K. Two very weak anomalies were found around 80K and 140K. Thermal conductivity measurements have also been performed and there was no detectable anomaly. The results are discussed in view of actual proposed interpretations.     

A Trigger of Coupled Singularities

By using example of nonlinear dynamics of a pair of coupled gears, the phenomenon of appearance and disappearance of a trigger of coupled singularities and homoclinic orbits in the form of number eight in the phase portrait in the phase plane is investigated. That phenomenon is an accompanying phenomenon of loss of stability of the local unique equilibrium position. For a generalized case under certain conditions, a theorem of the appearance of a trigger of coupled singularities in a nonlinear dynamical conservative system, the first derivative of the system potential energy which is a product of two periodic functions with different periods, and one bifurcation parameter, which is the cause for the appearance of new roots of these two functions, is defined.     

Dynamics of coupled systems

A survey in the form of a review of the author’s research results in the area of dynamics of coupled rotations and coupled systems is presented. The theorem on the existence of a trigger of the coupled singularities and the separatrix in the form of the number eight is presented with a few examples of coupled rotations of the simple systems with debalances. Also, a survey of models and dynamics of coupled systems composed of a number of deformable bodies (plates, beams or belts) with different properties of materials and discrete layer properties is presented and mathematically described. The constitutive stress–strain relations for materials of the coupled sandwich structure elements are presented for different properties: elastic, viscoelastic and creeping. The characteristic modes of the coupled system vibrations are obtained and analyzed for different kinds of materials and structure composition. The visualization of the characteristic numbers and modes and eigenamplitude forms are presented. Structural analysis of sandwich structure vibrations is done.     

Carbon-13 chemical shifts of inverted carbon atoms

The inverted carbons in 2,4-methano-2,4-dehydroadamantane are shielded by 14.3 ppm relative to the corresponding carbons in 2,4-methanoadamantane. This was explained by the balance of the inverted carbon hybridization deshielding, the shielding effect of the cyclopropane rings formed, and the change in the influence of the neighbouring atoms.     

Mass moment vector applications to the multi body dynamics with coupled rotations about no intersecting axes

Multi body system contains finite number of rigid bodies that are placed on each axis, which do not intersect each other. Derivatives of the linear momentum and angular momentum with respect to time by use mass moment vectors and vector rotators for pole and axis, are determined. A number of theorems are defined. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Energy surfaces of rare-earth silicide films on Si(1 1 1)

We report on angle-resolved photoelectron spectroscopy results of thin dysprosium-silicide layers formed on Si(1 1 1), taken with a toroidal analyzer allowing to image the energy surfaces in k_||-space. At monolayer dysprosium coverages, where hexagonal DySi₂ grows with a 1×1 superstructure, electron pockets are observed at the points with highly anisotropic effective masses, and around a hole pocket at the point also an anisotropic dispersion is found. The band filling of these two bands amounts to one, indicating an even number of electrons assigned to the surface unit cell. Similar features are found for multilayer coverages, where hexagonal Dy₃Si₅ layers are formed with a superstructure. Here, the influence of zone folding effects due to the reconstructed layers in the bulk silicide is only weak because of the high surface sensitivity of the experiments.     

Peptide-mediated blood-brain barrier transport of polymersomes

A polymeric nanocarrier: Polymersomes tagged with a dodecamer peptide that recognizes gangliosides GM1 and GT1b are shown to cross the blood-brain barrier, both in an in?vitro model and in?vivo. The combination of polymeric vesicles with a small GM1-binding peptide and GM1/GT1b gangliosides as targeting sites for blood-brain barrier transport is unprecedented.