Dietmar Zellner

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UNLABELLED Non-linear phenomena are observed with enzyme kinetics, protein binding, pharmacokinetics or pharmacodynamics. The Hill equation, the Michaelis-Menten equation extended by a power coefficient, is traditionally used for sigmoid curve fitting. Sigmoid saturation phenomena can also be described by exponential functions (1-exp), extended by a power(More)
Zebrafish (Danio rerio) are widely used in developmental research, but still not much is known about the role of the environment in their development. Zebrafish are a highly social organism; thus exposure to, or isolation from, social environments may have profound developmental effects. Details of rearing conditions are often sparse in the zebrafish(More)
The assessment of sample size in clinical trials comparing means requires a variance estimate of the main efficacy variable. If no reliable information about the variance of the key response is available at the beginning of a clinical trial, the use of data from the first 'few' patients entered in the trial ('internal pilot') may be appropriate to estimate(More)
BACKGROUND Phenacetin was removed from the German market in 1986 and was replaced mainly in analgesic compounds by acetaminophen. Our objective was to examine the effect of this measure on the incidence of analgesic nephropathy in light of the changes in other end-stage renal diseases. METHODS We therefore compared the proportion of renal diseases in all(More)
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