Automatation of an analytical laboratory for the determination of drug levels in body fluids

Summary For the specific determination of drug levels in body fluids selective chromatographic methods are now widely used. Because these methods are time-consuming, there is a need for automatation, especially when many samples are to be run. This automatation needs special precautions so that the quality of analyses is controlled and maintained. Possibilities for automatation of chromatographic methods and solutions of the attendant problems are discussed.

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Automatisierung der Bestimmung von Arzneispiegeln in Körperflüssigkeiten

Zusammenfassung Die spezifische Bestimmung von Arzneimittelspiegeln in Körperflüssigkeiten erfolgt heute überwiegend mit chromatographischen Methoden. Besonders bei der Bestimmung größerer Serien wird es notwendig, diese zu automatisieren. Dazu sind jedoch spezielle Vorkehrungen zur Kontrolle und Aufrechterhaltung der Qualität der Analysenergebnisse zu treffen. Möglichkeiten zur Automatisierung chromatographischer Bestimmungsmethoden und Vorschläge zur Lösung der damit zusammenhängenden Probleme werden diskutiert.

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Herrn Prof. Dr. Eberhard von Wasielewski zu seinem 60. Geburtstag gewidmet.

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Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980.     

High-performance AlGaAs-based VCSELs emitting in the 760 nm wavelength range

Vertical-cavity surface-emitting lasers (VCSELs) showing continuous-wave operation with emission wavelengths ranging between 717 and 790 nm have been fabricated. The samples are grown by solid source molecular beam epitaxy on GaAs substrates and are entirely based on the AlGaAs material system. A maximum single-mode output power of 2.0 mW is obtained at 754 nm wavelength by using the inverted surface relief technique.     

Comparison of software for computing the action of the matrix exponential

The implementation of exponential integrators requires the action of the matrix exponential and related functions of a possibly large matrix. There are various methods in the literature for carrying out this task. In this paper we describe a new implementation of a method based on interpolation at Leja points. We numerically compare this method with other codes from the literature. As we are interested in applications to exponential integrators we choose the test examples from spatial discretization of time dependent partial differential equations in two and three space dimensions. The test matrices thus have large eigenvalues and can be nonnormal.     

Exponential multistep methods of Adams-type

The paper is concerned with the construction, implementation and numerical analysis of exponential multistep methods. These methods are related to explicit Adams methods but, in contrast to the latter, make direct use of the exponential and related matrix functions of a (possibly rough) linearization of the vector field. This feature enables them to integrate stiff problems explicitly in time.