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Biomedical subjects

E Knobloch

Publications and source records attributed to E Knobloch.

At least 19 recordsLinked to original sources
PubMed2001

Long-wavelength instabilities of three-dimensional patterns.

Long-wavelength instabilities of steady patterns, spatially periodic in three dimensions, are studied. All potentially stable patterns with the symmetries of the simple-, face-centered- and body-centered-cubic lattices are considered. The results generalize the well-known Eckhaus, zigzag, and skew-varicose instabilities to three-dimensional patterns and are applied to two-species reaction-diffusion equations modeling the Turing instability.

Journal Article↗
PubMed2001

Oscillatory binary fluid convection in large aspect-ratio containers.

Direct numerical simulations of chevrons, blinking states, and repeated transients in binary fluid mixtures with a negative separation ratio heated from below are described. The calculations are performed in two-dimensional containers for experimental parameter values and boundary conditions. Quantitative agreement with the experiments of Kolodner [Phys. Rev. E 47, 1038 (1993)] is obtained, and the origin of the blinking and repeated transient states is elucidated.

Journal Article↗
PubMed1992

[Photoisomers of bilirubin in the blood of neonates during phototherapy].

In a group of mature neonates with hyperbilirubinaemia the authors investigated by chromatography, using the HPLC method, levels of bilirubin photoisomers before phototherapy, in the course of phototherapy and after its termination. The configuration isomer 4 Z, 15 E is detected in blood of all icteric neonates already before the onset of treatment in a mean concentration of 5.2 (s = 3.8) mumol/l, during phototherapy its mean concentration is 23.0 (s = 8.0) mumol/l. Photoisomers participate in non-conjugated bilirubinaemia on average by 10%: 92% are formed by isomer 4 Z, 15 E, 5% by isomer 4 E, 15 Z and 3% by the structural isomer lumirubin. On the day following discontinuation of treatment the mean photoisomer concentrations are significantly lower than during phototherapy and significantly higher than before its initiation.

Bilirubin↗
PubMed1991

Study of the mechanism of the photoisomerization and photooxidation of bilirubin using a model for the phototherapy of hyperbilirubinemia.

Liquid chromatography was employed for a study of photochemical degradation of bilirubin in the complex with human albumin, using a model system in the presence of riboflavin. The concentrations of bilirubin, the photoisomers and biliverdin were monitored. The reaction mechanism was verified using a quantified mathematical model and was represented by a reaction scheme. Photoisomerization is the initial process, followed by photooxidation to degradation products of the tetrapyrrole skeleton, with formation of biliverdin as an intermediate. The blood of newborns that were irradiated for treatment of hyperbilirubinemia was studied for the sake of comparison. The effect of some biochemically important substances was followed, in view of possible inhibition of the processes. The experimental results demonstrate that riboflavin acts as a catalyst, even at the concentrations typical for its occurrence in blood. The results are discussed from the point of view of the mechanism of bilirubin degradation during phototherapy.

Bilirubin↗