Grenzen der modernen Laser-Spektralanalyse

The different methods of laser spectroscopy allow the detection of few atoms in a laser beam. There are several theoretical, physical limitations of atom detection. However, in normal extreme trace analysis, in most cases, several limitations arise due to contamination problems in sample handling and problems connected with sample atomization.     

Möglichkeiten und Grenzen der genetischen Manipulation

Examples for genetic engineering are the transfer of nuclei between cells of higher animals and the introduction of heterologous DNA into bacteria by means of plasmids. The former approach will help to establish new ways in animal breeding, the latter provides bacterial cells that produce proteins of medical importance. The moral justification of related studies in man is still open, but the possible risks of gene technology can be coped with by adhering to proper safety regulations.     

Grenzen und Möglichkeiten der Immuntherapie von Tumoren

Immunological treatment of malignant human tumors has so far met with little success. Based on methods and insights obtained by investigation of corresponding animal models, this article attempts to elucidate the reasons for this failure and to suggest ways and means to improve immunotherapeutic approaches to human neoplasms.     

Die Entwicklung der Erdrinde

The key and the well established basis for our present understanding of the evolution of the earth's lithosphere is the continous creation of new oceanic lithosphere in the mid oceanic ridge system. Paleomagnetic evidence and the concept of global plate tectonics permit a quantitative reconstruction of the kinematic history of the lithosphere for the past 200 m.y. This leads to continent configurations very similar to those proposed by A. Wegener. Plate tectonic processes can be traced back until Precambrian times. Before that, due to the generally higher temperature of the earth, the evolution was apparently governed by different processes. Thermal convection and gravitational instabilities are considered as driving forces for the lithosphere.