University of Marburg

About: University of Marburg is a education organization based out in Marburg, Germany. It is known for research contribution in the topics: Population & Gene. The organization has 23195 authors who have published 42907 publications receiving 1506069 citations. The organization is also known as: Philipps University of Marburg & Philipps-Universität.

Effect of doping on the density-of-states distribution and carrier hopping in disordered organic semiconductors

Abstract: The effect of doping on the density-of-states (DOS) distribution and charge-carrier transport in a disordered hopping system is considered analytically. It is shown that doping such a system produces a random distribution of dopant ions, which Coulombically interact with carriers localized in intrinsic hopping sites. This interaction further increases the energy disorder and broadens the deep tail of the DOS distribution. Therefore, doping of a disordered organic semiconductor, on the one hand, increases the concentration of charge carriers and lifts up the Fermi level but, on the other hand, creates additional deep Coulombic traps of the opposite polarity. While the former effect facilitates conductivity, the latter strongly suppresses the carrier hopping rate. A model of hopping in a doped disordered organic semiconductor is suggested. It is shown that the doping efficiency strongly depends upon the energy disorder and external electric field.

Polymer microcapsules as mobile local pH-sensors

Abstract: Polyelectrolyte microcapsules have been loaded with a pH-sensitive, high molecular weight SNARF-1-dextran conjugate. SNARF-1 exhibits a significant pH-dependent emission shift from green to red fluorescence under acidic and basic conditions, respectively. The unique spectral properties of the dye were maintained after the encapsulation. By investigating both human breast cancer cells and fibroblasts, we were able to follow the pH change of the local environment of SNARF-1-filled capsules during the transition from the alkaline cell medium to the acidic endosomal/lysosomal compartments. The incorporation of magnetite nanoparticles and an additional pH-insensitive fluorophore within the capsule shell resulted in a novel type of sensor system based on multifunctional polymer capsules.

Variability-aware parsing in the presence of lexical macros and conditional compilation

Abstract: In many projects, lexical preprocessors are used to manage different variants of the project (using conditional compilation) and to define compile-time code transformations (using macros). Unfortunately, while being a simple way to implement variability, conditional compilation and lexical macros hinder automatic analysis, even though such analysis is urgently needed to combat variability-induced complexity. To analyze code with its variability, we need to parse it without preprocessing it. However, current parsing solutions use unsound heuristics, support only a subset of the language, or suffer from exponential explosion. As part of the TypeChef project, we contribute a novel variability-aware parser that can parse almost all unpreprocessed code without heuristics in practicable time. Beyond the obvious task of detecting syntax errors, our parser paves the road for further analysis, such as variability-aware type checking. We implement variability-aware parsers for Java and GNU C and demonstrate practicability by parsing the product line MobileMedia and the entire X86 architecture of the Linux kernel with 6065 variable features.