Über das asymptotische Verhalten von Lösungen gewöhnlicher asymptotisch periodischer Differentialgleichungen mit zufälligen Parametern

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Obtaining Unique Solutions to Hanai's Equation as Used in Wobschall's Semidisperse Model of Moist Soil

A method for obtaining unique solutions to Hanai's equation for two-phase dielectric mixtures is presented. It uses back substitution in the original equation and repeated application of the criteria Re(?) ? 1 and Im(?) ? 0. The method increases the versatility of computer programs for solving Wobschall's semidisperse model of moist soil.     

Tyrosine decarboxylase

We have developed a highly sensitive and rapid spectrophotometric assay for tyrosine decarboxylase that can be applied to determining pyridoxal-5'-phosphate. In the assay, tyramine, a product of tyrosine decarboxylation, reacts with 2,4,6-trinitrobenzenesulfonic acid to give a product soluble in toluene whereas tyrosine does not. We determined the amount of tyramine produced enzymatically by reading the absorbance at 340 nm of a toluene extract of the reaction mixture. This method is capable of detecting as low as 2.9 micrograms/mL of the enzyme. Using this method, we find the Km for tyrosine decarboxylase from Streptococcus faecalis to be 3.55 X 10(-4)M. We have also developed a specific and extremely sensitive method for determining pyridoxal-5'-phosphate, a cofactor of the enzyme, by using this spectrophotometric assay with apotyrosine decarboxylase.     

One-dimensional random walk with unequal step lengths restricted by an absorbing barrier

A one-dimensional random walk with unequal step lengths restricted by an absorbing barrier is considered as follows: (1) enumeration of the number of non-decreasing paths in a non-negative quadrant of the integral square lattice and in the inside of a polygon, (2) evaluation of transient (or absorption) probabilities for the random walk.     

Low-noise two-dimensional electron gas FET

Two-dimensional electron gas FETs (TEGFETs) have been fabricated on an N-AlGaAs-GaAs heterojunction. Microwave results at 10 GHz are: NF=2.3 dB, Gass=10.3 dB and Gmax=13.2 dB. These first results obtained on nonoptimised material and processing suggest that TEGFET can be superior to a conventional GaAs FET.     

A new megastigmane sulphoglycoside and polyphenolic constituents from pericarps of Garcinia mangostana

A megastigmane sulphoglycoside together with three phenolic compounds were isolated from the water-soluble fraction of the pericarps of Garcinia mangostana. The structure of the new compound was determined as 4-O-sulpho-β-d-glucopyranosyl abscisate (1) by spectroscopic data. Proanthocyanidin A2 (2) showed potent α-glucosidase inhibitory and DPPH scavenging activities with IC₅₀ values of 3.46 and 11.6 μM, respectively.     

Qualitative properties of strongly pseudomonotone variational inequalities

Qualitative properties of strongly pseudomonotone variational inequalities such as solution existence, stability and global error bound are studied in this paper.