Gregor Witte

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Aluminium (Al) absorption was studied using an isolated in vitro vascularly perfused rat intestinal preparation. Al was introduced into the lumen as AlCl3, Al(NO3)3 or Al lactate to give final concentrations equivalent to 0.625, 1.25, 2.50, 5.00, or 10.00 g/L of Al. The intestinal tissue remained viable up to 5.0 g/L of Al. The amount of Al associated with(More)
The formation of one-dimensional, unidirectional nanoscopic molecular structures by self-assembly on metal substrates with a long range ordering up to several hundred nanometers has been achieved by a novel mechanism, an oscillatory modulation of the adsorption energy due to charge-density waves related to a surface state. For the case of pentacene (C22H14)(More)
Smart nanoenvironments were obtained by cell-imprinted substrates based on mature and dedifferentiated chondrocytes as templates. Rabbit adipose derived mesenchymal stem cells (ADSCs) seeded on these cell-imprinted substrates were driven to adopt the specific shape (as determined in terms of cell morphology) and molecular characteristics (as determined in(More)
Chemical-vapor-deposited large-area graphene is employed as the coating of transparent substrates for the growth of the prototypical organic n-type semiconductor perfluoropentacene (PFP). The graphene coating is found to cause face-on growth of PFP in a yet unknown substrate-mediated polymorph, which is solved by combining grazing-incidence X-ray(More)
When aromatic self-assembled monolayers (SAMs) are electron-irradiated, intermolecular cross-links are formed and the SAMs transform into carbon nanosheets with molecular thickness. These nanosheets have a very high mechanical stability and can withstand temperatures above 1000 K. In this report, we investigate the electron induced cross-linking of(More)
A theoretical analysis of charged adsorbates on a metal surface reveals a pronounced polarity asymmetry between electropositive and electronegative species, thus reproducing a well known but so far not properly understood experimental fact. For ionic adsorbates on metal surfaces, we analyze the several, often cancelling, terms that contribute to the change(More)
A light-addressable gold electrode modified with CdS and FePt or with CdS@FePt nanoparticles via an interfacial dithiol linker layer is presented. XPS measurements reveal that trans-stilbenedithiol provides high-quality self-assembled monolayers compared to benzenedithiol and biphenyldithiol, in case they are formed at elevated temperatures. The CdS(More)
Driven by research in the emerging field of organic electronics, self-assembled monolayers (SAMs) of aromatic molecules have attracted pronounced interest because they allow detailed studies of charge-transport processes across metal–organic interfaces, or have been used as contact primers to improve the properties of metal electrodes. To make the step from(More)
The molecular structure of thin pentacene (C(22)H(14)) films grown on a Cu(110) surface has been studied by means of He atom scattering, low energy electron diffraction, thermal desorption spectroscopy, x-ray photoelectron spectroscopy, and x-ray absorption spectroscopy. Depending on the actual film thickness three different crystalline phases have been(More)