Abstract: The present provides optical sensor based sensitive, label-free binding assay methods and kits for isothermal real-time detection of the binding of specific analytes (such as nucleic acids, proteins and low molecular weight antigenic or receptor binding ligands) present in low amount in different biological samples. In the binding assays of the invention, the analyte is captured at the specifically pretreated solid surface of optical biosensors in specific recognition reactions (such as hybridization, specific protein-protein interactions and receptor-ligand interactions). The specificity of the methods of the invention is further enhanced by a second specific recognition step using a padlock probe comprising an indicator sequence designed to keep the products of a subsequently performed isothermal nucleic acid amplification method (e.g.

Abstract: In a process for determining the layer thickness of semiconductor layer structures, a sample of a multilayer semi-conductor (4) is placed in contact with an electrolyte (2) then subjected to anodic etching during which the depth of etching is determined by integration of the current. During etching, the sample (4) is also excited by an electric signal and the real component of the admittance and hence the conductance of the probe at the frequency of excitation is determined, the extreme values of this component are analyzed, and the values of the depth of etching corresponding to these extremes, which characterize the junctions between the layers of the sample (4) tested, are determined.