Abstract: A quantum cascade laser structure in accordance with the invention comprises a number of cascades (100), each of which comprises a number of alternately arranged quantum wells (110a to 110j) and barrier layers (105 to 105j). The material of at least one quantum well (110a to 110j) as well as the material of at least one barrier layer (105 to 105j) is under mechanical strain, with the respective strain being either a tensile strain or a compression strain. The quantum wells (110a to 110j) and barrier layers (105 to 105j) are engineered in the quantum cascade laser structure in accordance with the invention so that existing strains are largely compensated within a cascade (100). In the quantum cascade laser structure in accordance with the invention, each material of the quantum wells (110a to 110j) has only one constituent material and the material of at least one barrier layer (105d, 105e, 105f) has at least two constituent materials (111a, 111b, 112a, 112b, 113a, 113b).

Abstract: The present invention relates to new cytochemical and histochemical detection methods based on the enzymatic activity of poly-ADP-ribose-polymerases (PARP). In particular, the present invention provides methods and systems for cytochemical or histochemical detection of a molecule of interest based on detecting poly-ADP-ribose (PAR). Further, the present invention provides methods for screening for compounds altering the amount of NAD or analogs thereof in subcellular compartments based on detecting the amount of PAR formed in said subcellular compartment as well as methods for determining the spatial distribution of a molecule of interest. In a further aspect, the present invention provides systems and kits for conducting said methods as well as a new expression vectors suitable for said systems.

Abstract: A quantum cascade laser structure in accordance with the invention comprises a number of cascades (100), each of which comprises a number of alternately arranged quantum wells (110a to 110j) and barrier layers (105 to 105j). The material of at least one quantum well (110a to 110j) as well as the material of at least one barrier layer (105 to 105j) is under mechanical strain, with the respective strain being either a tensile strain or a compression strain. The quantum wells (110a to 110j) and barrier layers (105 to 105j) are engineered in the quantum cascade laser structure in accordance with the invention so that existing strains are largely compensated within a cascade (100). In the quantum cascade laser structure in accordance with the invention, each material of the quantum wells (110a to 110j) has only one constituent material and the material of at least one barrier layer (105d, 105e, 105f) has at least two constituent materials (111a, 111b, 112a, 112b, 113a, 113b).

Abstract: A quantum cascade laser structure in accordance with the invention comprises a number of cascades (100), each of which comprises a number of alternately arranged quantum wells (110a to 110j) and barrier layers (105 to 105j). The material of at least one quantum well (110a to 110j) as well as the material of at least one barrier layer (105 to 105j) is under mechanical strain, with the respective strain being either a tensile strain or a compression strain. The quantum wells (110a to 110j) and barrier layers (105 to 105j) are engineered in the quantum cascade laser structure in accordance with the invention so that existing strains are largely compensated within a cascade (100). In the quantum cascade laser structure in accordance with the invention, each material of the quantum wells (110a to 110j) has only one constituent material and the material of at least one barrier layer (105d, 105e, 105f) has at least two constituent materials (111a, 111b, 112a, 112b, 113a, 113b).