We have investigated the morphology and surface forces of protein A adsorbed on mica surface in the protein solutions of various concentrations. The force-distance curves, measured with a surface force apparatus (SFA), were interpreted in terms of two different regimens: a "large-distance" regimen in which an electrostatic double-layer force dominates, and an "adsorbed layer" regimen in which a force of steric origin dominates. To further clarify the forces of steric origin, the surface morphology of the adsorbed protein layer was investigated with an atomic force microscope (AFM) because the steric repulsive forces are strongly affected by the adsorption mode of protein A molecules on mica. At lower protein concentrations (2 ppm, 10 ppm), protein A molecules were adsorbed "side-on" parallel to the mica surfaces, forming a monolayer of approximately 2.5 nm. AFM images at higher concentrations (30 ppm, 100 ppm) showed protruding structures over the monolayer, which revealed that the adsorbed protein A molecules had one end oriented into the solution, with the remainder of each molecule adsorbed side-on to the mica surface. These extending ends of protein A overlapped each other and formed a "quasi-double layer" over the mica surface. These AFM images proved the existence of a monolayer of protein A molecules at low concentrations and a "quasi-double layer" with occasional protrusions at high concentrations, which were consistent with the adsorption mode observed in the force-distance curves.

Treatment of dithiirane 1-oxides 9 with (Ph 3 P) 2 Pt(η 2 -CH 2 = CH 2 ) (3) yielded the corresponding four-membered (sulfenato−thiolato)Pt II complexes 7 in high yields. The structures of 7 were determined by 31 P NMR spectroscopy and, for 7e, X-ray crystallography. Treatment of dithiirane 8 with

Sind Überlegungen zur Zukunft relevant oder dienen sie nur der Zerstreuung? Regelmäßig werden wichtige Grundüberzeugungen aufgrund wissenschaftlicher Erkenntnisse verworfen, mit oft tiefgreifenden Folgen für die Gesellschaft. Falsche Annahmen lassen sich im Nachhinein leicht ausmachen, aber lassen sie sich auch in der Gegenwart erkennen, und lassen sich aus der Erkenntnis Schlussfolgerungen für die Zukunft ziehen? Dieser Essay diskutiert gesellschaftlich akzeptierte Annahmen und das Potenzial der Naturwissenschaften, sie zu widerlegen.

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