@article{GrassdosSantosPelster2011,
  author    = {Grass, T. D. and dos Santos, Francisca E. A. and Pelster, Axel},
  title     = {Real-time Ginzburg-Landau theory for bosons in optical lattices},
  series = {Laser physics},
  volume    = {21},
  journal   = {Laser physics},
  number    = {8},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {1054-660X},
  doi       = {10.1134/S1054660X11150096},
  pages     = {1459 -- 1463},
  year      = {2011},
  abstract  = {Within the Schwinger-Keldysh formalism we derive a Ginzburg-Landau theory for the Bose-Hubbard model which describes the real-time dynamics of the complex order parameter field. Analyzing the excitations in the vicinity of the quantum phase transitions it turns out that particle/hole dispersions in the Mott phase map continuously onto corresponding amplitude/phase excitations in the superfluid phase. Furthermore, in the superfluid phase we find a sound mode, which is in accordance with recent Bragg spectroscopy measurements in the Bogoliubov regime, as well as an additional gapped mode, which seems to have been detected via lattice modulation.},
  language  = {en}
}
@article{DraudePelsterKoersgenetal.2014,
  author    = {Draude, F. and Pelster, A. and Koersgen, M. and Kassenboehmer, R. and Schwerdtle, Tanja and Muething, J. and Arlinghaus, H. F.},
  title     = {ToF-SIMS imaging of plasma membrane lipids with sub-micrometer resolution},
  series = {Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films},
  volume    = {46},
  journal   = {Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0142-2421},
  doi       = {10.1002/sia.5576},
  pages     = {127 -- 130},
  year      = {2014},
  abstract  = {Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used for label-free analyses of the molecular lateral distribution of two different epithelial cell membranes (PANC-1 and UROtsa). The goal of the research was to enhance the ion yield of specific membrane molecules for improving the membrane imaging capability of ToF-SIMS on the nanoscale lateral dimension. For this task, a special silicon wafer sandwich preparation technique was optimized using different wafer materials, spacers, and washing procedures. Under optimized preparation conditions, the yield could be significantly enhanced, allowing imaging of the inhomogeneous distribution of phosphocholine (common head group for phosphatidylcholine and sphingomyelin) of a PANC-1 cell membrane's outer lipid layer with a lateral resolution of less than 200nm. Copyright (c) 2014 John Wiley \& Sons, Ltd.},
  language  = {en}
}
@article{DraudeGallaPelsteretal.2013,
  author    = {Draude, F. and Galla, S. and Pelster, Axel and Tentschert, J. and Jungnickel, H. and Haase, Alfred and Mantion, Alexandre and Thuenemann, Andreas F. and Taubert, Andreas and Luch, A. and Arlinghaus, H. F.},
  title     = {ToF-SIMS and Laser-SNMS analysis of macrophages after exposure to silver nanoparticles},
  series = {Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films},
  volume    = {45},
  journal   = {Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films},
  number    = {1},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0142-2421},
  doi       = {10.1002/sia.4902},
  pages     = {286 -- 289},
  year      = {2013},
  abstract  = {Silver nanoparticles (SNPs) are among the most commercialized nanoparticles because of their antibacterial effects. Besides being employed, e. g. as a coatingmaterial for sterile surfaces in household articles and appliances, the particles are also used in a broad range of medical applications. Their antibacterial properties make SNPs especially useful for wound disinfection or as a coating material for prostheses and surgical instruments. Because of their optical characteristics, the particles are of increasing interest in biodetection as well. Despite the widespread use of SNPs, there is little knowledge of their toxicity. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and laser post-ionization secondary neutral mass spectrometry (Laser-SNMS) were used to investigate the effects of SNPs on human macrophages derived from THP-1 cells in vitro. For this purpose, macrophages were exposed to SNPs. The SNP concentration ranges were chosen with regard to functional impairments of the macrophages. To optimize the analysis of the macrophages, a special silicon wafer sandwich preparation technique was employed; ToF-SIMS was employed to characterize fragments originating from macrophage cell membranes. With the use of this optimized sample preparation method, the SNP-exposed macrophages were analyzed with ToF-SIMS and with Laser-SNMS. With Laser-SNMS, the three-dimensional distribution of SNPs in cells could be readily detected with very high efficiency, sensitivity, and submicron lateral resolution. We found an accumulation of SNPs directly beneath the cell membrane in a nanoparticular state as well as agglomerations of SNPs inside the cells.},
  language  = {en}
}