Ruled surfaces of finite type in 3- dimensional minkowski space

We show that a ruled surface M in E₁ ³ is of finite type if and only if M is minimal, or M is a part of a circular cylinder, or M is a part of a hyperbolic cylinder, or M is an isoparametric surface with null rules. We also give a complete classification of isoparametric ruled surfaces with null rules.     

Biological reference materials in routine analysis: Results from the German Food Contamination Monitoring Programme

Summary Within the research project German Food Contamination Monitoring Programme, selected foodstuffs have to be examined by the official food control laboratories. Contents of pesticides and heavy metals have to be determined by means of routine analysis. Biological reference materials are used in collaborative studies and in parallel investigations for analytical quality assurance. Using lead as an example, results obtained for three reference materials are discussed.     

D-Penicillamine—Production and Properties

The non-naturally occurring amino acid D -penicillamine, originally only of interest as a key substance in the structural elucidation and total synthesis of penicillins is gaining increasing importance as a therapeutic, particularly in the long-term treatment of rheumatoid arthritis. D -Penicillamine which previously was obtained semi-synthetically by degradation of penicillins can now be totally synthesized using a new process which starts from isobutyraldehyde, sulfur, ammonia, and hydrogen cyanide and yields the racemate which is then selectively resolved. The biochemical behavior of D -penicillamine—chelate formation with heavy metal ions, cleavage of disulfide bridges, and condensation with aldehyde groups—affords information related to its therapeutic activity.     

Chemische Untersuchung der Königskerzenbl\ten (Flores verbasci)

Ohne Zusammenfassung     

Nachweis der Salicyls?ure in Wein und Fruchts?ften

Ohne Zusammenfassung