Physik der biologischen Gestaltbildung

In each generation cycle of a higher organism, a complex structure is formed under the instruction of the genes. In this process morphogenetic fields (probably spatial concentration patterns of substances) are involved which elicit cell responses giving rise to visible pattern and form. Autocatalytic short-range activation in conjunction with long-range (“lateral”) inhibition is capable of generating striking concentration patterns starting from near-uniform distributions. No features unusual in molecular biology are required, and self-regulatory properties observed experimentally in biological development can be accounted for. Cell responses to morphogenetic fields can include cell differentiation and the generation of bending moments, curvature and form in cell sheets giving rise to defined forms in organs and organisms. It appears that biological pattern formation is explicable on the basis of known physical laws and processes.     

Chemische Reaktionen von Phenylarsinverbindungen

In an equilibrium reaction, phenylarsine dichloride (PFIFFIKUS) reacts rapidly with alcohols at room temperature to yield phenylarsine bisether and phenylarsine chloride ether. The reactions, however, are not quantitative. The derivatives were identified using mass spectrometry.     

Aluminium levels in the blood plasma of persons working in the aluminium industry

Due to the exposure to alumina in the air, workers in the primary aluminium industry are expected to exhibit a higher aluminium exposure than the general population. The additional daily intake will be less than 20 mg. The determination of aluminium in blood plasma of electrolysis-workers by flameless atomic absorption spectrometry revealed levels before shift in the range of 20–30 g/L compared to levels of less than 3 g/L in a non-occupationally exposed group. These levels refer to work in old plants with unhooded pots. The plasma levels can rise up to 60 g/L during the shift. A similar rapid change of the levels during work is seen in the urine values. Due to the delay in excretion the maximal values in the range of 5 g/h are found four hours after cessation of work. It seems therefore that only preshift samples give a reliable measure of the body burden. Compared to the much higher levels in dialysis patients the observed values in aluminium workers are not considered to be of relevance to health.