Application of NMR Spectroscopy and Imaging in Heterogeneous Biocatalysis

Heterogeneously catalyzed enzymatic glucose isomerization was considered as a model process to extend the application of nuclear magnetic resonance (NMR) and magnetic resonance imaging techniques to the studies of biocatalytic processes and heterogeneous biocatalysts. It has been demonstrated that the T ₂ times of glucose are different for its aqueous solution in the pores of an unmodified porous support and in a heterogeneous biocatalyst, comprising bacterial cells immobilized on the same support. This observation has been used to map the spatial distribution of the active component within a packed bed of biocatalyst in a model reactor. ¹³C NMR spectroscopy was applied to follow the progress of glucose isomerization catalyzed by the heterogeneous biocatalyst in a batch reactor. The utilization of proton spin decoupling and nuclear Overhauser effect was shown to be necessary to obtain high signal-to-noise ratio in the natural abundance ¹³C NMR spectra of a glucose–fructose syrup present in the packed bed of biocatalyst. The spectra thus obtained were suitable for the quantification of the glucose-to-fructose ratio achieved in the biocatalytic reaction.     

Absolutbestimmung der spezifischen Aktivität 35S-haltiger Substanzen

Als wesentlichste Vorausselzungen für eine präzise Absolutbestimmung der spezifischen Aktivität ³³S-haltiger Substanzen werden die Sorption von SO₂ an den Zählrohren und der Füllapparatur, die Beeinflussung des Gasentladungsmechanismus im beschränkten Proportionalbereich durch negativ geladene SO₂-Ionen und die kinetischen Isotopieeffekte bei nicht hundertprozentiger Überführung der Ausgangssubstanzen zu Meβgas untersucht. Speziell beschrieben werden die Umsetzung von Natriumsulfat bzw. Schwefelsäure in wäβriger Lösung und Thioharstoff zu Bariumsulfat und dessen Verbrennung zu Schwefeldioxid. Der Gesamtfehlre, mit dem die Angabe der spezifischen Aktivität für die genannten Ausgangssubstanzen behaftel ist, wird angegeben.     

On the Effects of UV Radiation on the Release Ability of Glucose Embedded in Hydroxypropyl Cellulose Films

New drug delivery systems based on hydroxypropyl cellulose (HPC) and different percents of glucose were prepared and characterized to check their suitability as UV resistant patches. The spectral absorption properties of the HPC and HPC-glucose blends before and after UV irradiation were analyzed. The surface polarity and hydrophilicity were correlated with the morphology of the films and analyzed with respect to the UV exposure time and the embedded amount of glucose. The effects of UV radiation on in vitro evaluation of glucose release from the HPC films are reported. The mechanism involved in the drug release process, evaluated using the Korsmeyer-Peppas equation, was dependent on the introduced amount of glucose and less on the UV exposure time. A more polar, smoother, and less dense surface releases the glucose over larger periods of time, making the system with lower percents of glucose more adequate for the pursued purpose.     

Splitting of Spectra in Anharmonic Oscillators Described by Kratzer Potential Function

A perturbation theory model that describes splitting of the spectra in highly symmetrical molecular species in electrostatic field is proposed. An anahrmonic model of a two-dimensional oscillator having Kratzer potential energy functionis used to model the molecular species and to represent the unperturbed system. A selection rule for the radial quantum number of the oscillator is derived. The eigenfunctions of a two-dimensional anharmonic oscillator in cylindrical coordinates are used for the matrix elements representing the probability for energy transitions in dipole approximation to be calculated. Several forms of perturbation operators are proposed to model the interactionbetween the polyatomic molecular species and an electrostatic field. It is found that the degeneracy is removed in the presence of the electric field and spectral splitting occurs. Anharmonic approximation for the unperturbed system is more accurate and reliable representation of a real polyatomic molecular species.     

Bioactive materials for bone regeneration based on zinc-modified hydroxyapatite

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Synthesis and structure of new chlorine containing calix[4]resorcinols

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An efficient synthesis of new polyfunctional hexahydro pyrido[1,2-a]pyrazin-1-ones

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Pericyclic reactions in the synthesis of new 5-aryl-5,6-dihydroquinolino[2,1-b]quinazolin-12-ones

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