@misc{BartoloniJinMarcaidaetal.2015,
  author    = {Bartoloni, Marco and Jin, Xian and Marcaida, Maria Jos{\´e} and Banha, Joao and Dibonaventura, Ivan and Bongoni, Swathi and Bartho, Kathrin and Gr{\"a}bner, Olivia and Sefkow, Michael and Darbre, Tamis and Reymond, Jean-Louis},
  title     = {Bridged bicyclic peptides as potential drug scaffolds},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81239},
  year      = {2015},
  abstract  = {Double cyclization of short linear peptides obtained by solid phase peptide synthesis was used to prepare bridged bicyclic peptides (BBPs) corresponding to the topology of bridged bicyclic alkanes such as norbornane. Diastereomeric norbornapeptides were investigated by 1H-NMR, X-ray crystallography and CD spectroscopy and found to represent rigid globular scaffolds stabilized by intramolecular backbone hydrogen bonds with scaffold geometries determined by the chirality of amino acid residues and sharing structural features of β-turns and α-helices. Proteome profiling by capture compound mass spectrometry (CCMS) led to the discovery of the norbornapeptide 27c binding selectively to calmodulin as an example of a BBP protein binder. This and other BBPs showed high stability towards proteolytic degradation in serum.},
  language  = {en}
}
@misc{SchulzeUtechtMoldtetal.2015,
  author    = {Schulze, Michael and Utecht, Manuel Martin and Moldt, Thomas and Przyrembel, Daniel and Gahl, Cornelius and Weinelt, Martin and Saalfrank, Peter and Tegeder, Petra},
  title     = {Nonlinear optical response of photochromic azobenzene-functionalized self-assembled monolayers},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81198},
  year      = {2015},
  abstract  = {The combination of photochromic and nonlinear optical (NLO) properties of azobenzene-functionalized self-assembled monolayers (SAMs) constitutes an intriguing step towards novel photonic and optoelectronic devices. By utilizing the second-order NLO process of second harmonic generation (SHG), supported by density-functional theory and correlated wave function method calculations, we demonstrate that the photochromic interface provides the necessary prerequisites en route towards possible future technical applications: we find a high NLO contrast on the order of 16\% between the switching states. These are furthermore accessible reversibly and with high efficiencies in terms of cross sections on the order of 10-18 cm2 for both photoisomerization reactions, i.e., drivable by means of low-power LED light sources. Finally, both photostationary states (PSSs) are thermally stable at ambient conditions.},
  language  = {en}
}
@misc{GuhaWarsinkeTientcheuetal.2015,
  author    = {Guha, S. and Warsinke, A. and Tientcheu, Ch. M. and Schmalz, K. and Meliani, C. and Wenger, Ch.},
  title     = {Label free sensing of creatinine using a 6 GHz CMOS near-field dielectric immunosensor},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81177},
  year      = {2015},
  abstract  = {In this work we present a CMOS high frequency direct immunosensor operating at 6 GHz (C-band) for label free determination of creatinine. The sensor is fabricated in standard 0.13 μm SiGe:C BiCMOS process. The report also demonstrates the ability to immobilize creatinine molecules on a Si3N4 passivation layer of the standard BiCMOS/CMOS process, therefore, evading any further need of cumbersome post processing of the fabricated sensor chip. The sensor is based on capacitive detection of the amount of non-creatinine bound antibodies binding to an immobilized creatinine layer on the passivated sensor. The chip bound antibody amount in turn corresponds indirectly to the creatinine concentration used in the incubation phase. The determination of creatinine in the concentration range of 0.88-880 μM is successfully demonstrated in this work. A sensitivity of 35 MHz/10 fold increase in creatinine concentration (during incubation) at the centre frequency of 6 GHz is gained by the immunosensor. The results are compared with a standard optical measurement technique and the dynamic range and sensitivity is of the order of the established optical indication technique. The C-band immunosensor chip comprising an area of 0.3 mm2 reduces the sensing area considerably, therefore, requiring a sample volume as low as 2 μl. The small analyte sample volume and label free approach also reduce the experimental costs in addition to the low fabrication costs offered by the batch fabrication technique of CMOS/BiCMOS process.},
  language  = {en}
}
@misc{NiedlBeta2015,
  author    = {Niedl, Robert Raimund and Beta, Carsten},
  title     = {Hydrogel-driven paper-based microfluidics},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81083},
  pages     = {2452 -- 2459},
  year      = {2015},
  abstract  = {Paper-based microfluidics provide an inexpensive, easy to use technology for point-of-care diagnostics in developing countries. Here, we combine paper-based microfluidic devices with responsive hydrogels to add an entire new class of functions to these versatile low-cost fluidic systems. The hydrogels serve as fluid reservoirs. In response to an external stimulus, e.g. an increase in temperature, the hydrogels collapse and release fluid into the structured paper substrate. In this way, chemicals that are either stored on the paper substrate or inside the hydrogel pads can be dissolved, premixed, and brought to reaction to fulfill specific analytic tasks. We demonstrate that multi-step sequences of chemical reactions can be implemented in a paper-based system and operated without the need for external precision pumps. We exemplify this technology by integrating an antibody-based E. coli test on a small and easy to use paper device.},
  language  = {en}
}
@misc{NoechelReddyWangetal.2015,
  author    = {N{\"o}chel, Ulrich and Reddy, Chaganti Srinivasa and Wang, Ke and Cui, Jing and Zizak, Ivo and Behl, Marc and Kratz, Karl and Lendlein, Andreas},
  title     = {Nanostructural changes in crystallizable controlling units determine the temperature-memory of polymers},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81124},
  pages     = {8284 -- 8293},
  year      = {2015},
  abstract  = {Temperature-memory polymers remember the temperature, where they were deformed recently, enabled by broad thermal transitions. In this study, we explored a series of crosslinked poly[ethylene-co-(vinyl acetate)] networks (cPEVAs) comprising crystallizable polyethylene (PE) controlling units exhibiting a pronounced temperature-memory effect (TME) between 16 and 99 °C related to a broad melting transition (∼100 °C). The nanostructural changes in such cPEVAs during programming and activation of the TME were analyzed via in situ X-ray scattering and specific annealing experiments. Different contributions to the mechanism of memorizing high or low deformation temperatures (Tdeform) were observed in cPEVA, which can be associated to the average PE crystal sizes. At high deformation temperatures (>50 °C), newly formed PE crystals, which are established during cooling when fixing the temporary shape, dominated the TME mechanism. In contrast, at low Tdeform (<50 °C), corresponding to a cold drawing scenario, the deformation led preferably to a disruption of existing large crystals into smaller ones, which then fix the temporary shape upon cooling. The observed mechanism of memorizing a deformation temperature might enable the prediction of the TME behavior and the knowledge based design of other TMPs with crystallizable controlling units.},
  language  = {en}
}
@misc{MondalBehrensMatthesetal.2014,
  author    = {Mondal, Suvendu Sekhar and Behrens, Karsten and Matthes, Philipp R. and Sch{\"o}nfeld, Fabian and Nitsch, J{\"o}rn and Steffen, Andreas and Primus, Philipp-Alexander and Kumke, Michael Uwe and M{\"u}ller-Buschbaum, Klaus and Holdt, Hans-J{\"u}rgen},
  title     = {White light emission of IFP-1 by in situ co-doping of the MOF pore system with Eu3+ and Tb3+},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-79953},
  pages     = {4623 -- 4631},
  year      = {2014},
  abstract  = {Co-doping of the MOF 3∞[Zn(2-methylimidazolate-4-amide-5-imidate)] (IFP-1 = Imidazolate Framework Potsdam-1) with luminescent Eu3+ and Tb3+ ions presents an approach to utilize the porosity of the MOF for the intercalation of luminescence centers and for tuning of the chromaticity to the emission of white light of the quality of a three color emitter. Organic based fluorescence processes of the MOF backbone as well as metal based luminescence of the dopants are combined to one homogenous single source emitter while retaining the MOF's porosity. The lanthanide ions Eu3+ and Tb3+ were doped in situ into IFP-1 upon formation of the MOF by intercalation into the micropores of the growing framework without a structure directing effect. Furthermore, the color point is temperature sensitive, so that a cold white light with a higher blue content is observed at 77 K and a warmer white light at room temperature (RT) due to the reduction of the organic emission at higher temperatures. The study further illustrates the dependence of the amount of luminescent ions on porosity and sorption properties of the MOF and proves the intercalation of luminescence centers into the pore system by low-temperature site selective photoluminescence spectroscopy, SEM and EDX. It also covers an investigation of the border of homogenous uptake within the MOF pores and the formation of secondary phases of lanthanide formates on the surface of the MOF. Crossing the border from a homogenous co-doping to a two-phase composite system can be beneficially used to adjust the character and warmth of the white light. This study also describes two-color emitters of the formula Ln@IFP-1a-d (Ln: Eu, Tb) by doping with just one lanthanide Eu3+ or Tb3+.},
  language  = {en}
}
@misc{MegowRoehrSchmidtamBuschetal.2015,
  author    = {Megow, J{\"o}rg and R{\"o}hr, Merle I. S. and Schmidt am Busch, Marcel and Renger, Thomas and Mitrić, Roland and Kirstein, Stefan and Rabe, J{\"u}rgen P. and May, Volkhard},
  title     = {Site-dependence of van der Waals interaction explains exciton spectra of double-walled tubular J-aggregates},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-79978},
  pages     = {6741 -- 6747},
  year      = {2015},
  abstract  = {The simulation of the optical properties of supramolecular aggregates requires the development of methods, which are able to treat a large number of coupled chromophores interacting with the environment. Since it is currently not possible to treat large systems by quantum chemistry, the Frenkel exciton model is a valuable alternative. In this work we show how the Frenkel exciton model can be extended in order to explain the excitonic spectra of a specific double-walled tubular dye aggregate explicitly taking into account dispersive energy shifts of ground and excited states due to van der Waals interaction with all surrounding molecules. The experimentally observed splitting is well explained by the site-dependent energy shift of molecules placed at the inner or outer side of the double-walled tube, respectively. Therefore we can conclude that inclusion of the site-dependent dispersive effect in the theoretical description of optical properties of nanoscaled dye aggregates is mandatory.},
  language  = {en}
}
@misc{CroneAschnerSchwerdtleetal.2015,
  author    = {Crone, Barbara and Aschner, Michael A. and Schwerdtle, Tanja and Karst, Uwe and Bornhorst, Julia},
  title     = {Elemental bioimaging of Cisplatin in Caenorhabditis elegans by LA-ICP-MS},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-80031},
  pages     = {1189 -- 1195},
  year      = {2015},
  abstract  = {cis-Diamminedichloroplatinum(II) (Cisplatin) is one of the most important and frequently used cytostatic drugs for the treatment of various solid tumors. Herein, a laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) method incorporating a fast and simple sample preparation protocol was developed for the elemental mapping of Cisplatin in the model organism Caenorhabditis elegans (C. elegans). The method allows imaging of the spatially-resolved elemental distribution of platinum in the whole organism with respect to the anatomic structure in L4 stage worms at a lateral resolution of 5 μm. In addition, a dose- and time-dependent Cisplatin uptake was corroborated quantitatively by a total reflection X-ray fluorescence spectroscopy (TXRF) method, and the elemental mapping indicated that Cisplatin is located in the intestine and in the head of the worms. Better understanding of the distribution of Cisplatin in this well-established model organism will be instrumental in deciphering Cisplatin toxicity and pharmacokinetics. Since the cytostatic effect of Cisplatin is based on binding the DNA by forming intra- and interstrand crosslinks, the response of poly(ADP-ribose)metabolism enzyme 1 (pme-1) deletion mutants to Cisplatin was also examined. Loss of pme-1, which is the C. elegans ortholog of human poly(ADP-ribose) polymerase 1 (PARP-1) led to disturbed DNA damage response. With respect to survival and brood size, pme-1 deletion mutants were more sensitive to Cisplatin as compared to wildtype worms, while Cisplatin uptake was indistinguishable.},
  language  = {en}
}
@misc{GhoshCherstvyMetzler2014,
  author    = {Ghosh, Surya K. and Cherstvy, Andrey G. and Metzler, Ralf},
  title     = {Non-universal tracer diffusion in crowded media of non-inert obstacles},
  publisher = {The Royal Society of Chemistry},
  address   = {Cambridge},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-77128},
  pages     = {1847 -- 1858},
  year      = {2014},
  abstract  = {We study the diffusion of a tracer particle, which moves in continuum space between a lattice of excluded volume, immobile non-inert obstacles. In particular, we analyse how the strength of the tracer-obstacle interactions and the volume occupancy of the crowders alter the diffusive motion of the tracer. From the details of partitioning of the tracer diffusion modes between trapping states when bound to obstacles and bulk diffusion, we examine the degree of localisation of the tracer in the lattice of crowders. We study the properties of the tracer diffusion in terms of the ensemble and time averaged mean squared displacements, the trapping time distributions, the amplitude variation of the time averaged mean squared displacements, and the non-Gaussianity parameter of the diffusing tracer. We conclude that tracer-obstacle adsorption and binding triggers a transient anomalous diffusion. From a very narrow spread of recorded individual time averaged trajectories we exclude continuous type random walk processes as the underlying physical model of the tracer diffusion in our system. For moderate tracer-crowder attraction the motion is found to be fully ergodic, while at stronger attraction strength a transient disparity between ensemble and time averaged mean squared displacements occurs. We also put our results into perspective with findings from experimental single-particle tracking and simulations of the diffusion of tagged tracers in dense crowded suspensions. Our results have implications for the diffusion, transport, and spreading of chemical components in highly crowded environments inside living cells and other structured liquids.},
  language  = {en}
}
@misc{ShinCherstvyMetzler2014,
  author    = {Shin, Jaeoh and Cherstvy, Andrey G. and Metzler, Ralf},
  title     = {Kinetics of polymer looping with macromolecular crowding: effects of volume fraction and crowder size},
  publisher = {The Royal Society of Chemistry},
  address   = {Cambridge},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-76961},
  pages     = {472 -- 488},
  year      = {2014},
  abstract  = {The looping of polymers such as DNA is a fundamental process in the molecular biology of living cells, whose interior is characterised by a high degree of molecular crowding. We here investigate in detail the looping dynamics of flexible polymer chains in the presence of different degrees of crowding. From the analysis of the looping-unlooping rates and the looping probabilities of the chain ends we show that the presence of small crowders typically slows down the chain dynamics but larger crowders may in fact facilitate the looping. We rationalise these non-trivial and often counterintuitive effects of the crowder size on the looping kinetics in terms of an effective solution viscosity and standard excluded volume. It is shown that for small crowders the effect of an increased viscosity dominates, while for big crowders we argue that confinement effects (caging) prevail. The tradeoff between both trends can thus result in the impediment or facilitation of polymer looping, depending on the crowder size. We also examine how the crowding volume fraction, chain length, and the attraction strength of the contact groups of the polymer chain affect the looping kinetics and hairpin formation dynamics. Our results are relevant for DNA looping in the absence and presence of protein mediation, DNA hairpin formation, RNA folding, and the folding of polypeptide chains under biologically relevant high-crowding conditions.},
  language  = {en}
}
@misc{RoderHille2014,
  author    = {Roder, Phillip and Hille, Carsten},
  title     = {ANG-2 for quantitative Na+ determination in living cells by time-resolved fluorescence microscopy},
  publisher = {The Royal Society of Chemistry},
  address   = {Cambridge},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-76851},
  pages     = {1699 -- 1710},
  year      = {2014},
  abstract  = {Sodium ions (Na+) play an important role in a plethora of cellular processes, which are complex and partly still unexplored. For the investigation of these processes and quantification of intracellular Na+ concentrations ([Na+]i), two-photon coupled fluorescence lifetime imaging microscopy (2P-FLIM) was performed in the salivary glands of the cockroach Periplaneta americana. For this, the novel Na+-sensitive fluorescent dye Asante NaTRIUM Green-2 (ANG-2) was evaluated, both in vitro and in situ. In this context, absorption coefficients, fluorescence quantum yields and 2P action cross-sections were determined for the first time. ANG-2 was 2P-excitable over a broad spectral range and displayed fluorescence in the visible spectral range. Although the fluorescence decay behaviour of ANG-2 was triexponential in vitro, its analysis indicates a Na+-sensitivity appropriate for recordings in living cells. The Na+-sensitivity was reduced in situ, but the biexponential fluorescence decay behaviour could be successfully analysed in terms of quantitative [Na+]i recordings. Thus, physiological 2P-FLIM measurements revealed a dopamine-induced [Na+]i rise in cockroach salivary gland cells, which was dependent on a Na+-K+-2Cl- cotransporter (NKCC) activity. It was concluded that ANG-2 is a promising new sodium indicator applicable for diverse biological systems.},
  language  = {en}
}
@misc{MeyerSchulzJeibmannetal.2014,
  author    = {Meyer, S{\"o}ren and Schulz, Jacqueline and Jeibmann, Astrid and Taleshi, Mojtaba S. and Ebert, Franziska and Francesconi, Kevin and Schwerdtle, Tanja},
  title     = {Arsenic-containing hydrocarbons are toxic in the in vivo model Drosophila melanogaster},
  volume    = {11},
  number    = {6},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-76819},
  pages     = {2010 -- 2014},
  year      = {2014},
  abstract  = {Arsenic-containing hydrocarbons (AsHC) constitute one group of arsenolipids that have been identified in seafood. In this first in vivo toxicity study for AsHCs, we show that AsHCs exert toxic effects in Drosophila melanogaster in a concentration range similar to that of arsenite. In contrast to arsenite, however, AsHCs cause developmental toxicity in the late developmental stages of Drosophila melanogaster. This work illustrates the need for a full characterisation of the toxicity of AsHCs in experimental animals to finally assess the risk to human health related to the presence of arsenolipids in seafood.},
  language  = {en}
}
@misc{SchwarzeMuellerAstetal.2014,
  author    = {Schwarze, Thomas and M{\"u}ller, Holger and Ast, Sandra and Steinbr{\"u}ck, D{\"o}rte and Eidner, Sascha and Geißler, Felix and Kumke, Michael Uwe and Holdt, Hans-J{\"u}rgen},
  title     = {Fluorescence lifetime-based sensing of sodium by an optode},
  publisher = {The Royal Society of Chemistry},
  address   = {Cambridge},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-76785},
  pages     = {14167 -- 14170},
  year      = {2014},
  abstract  = {We report a 1,2,3-triazol fluoroionophore for detecting Na+ that shows in vitro enhancement in the Na+-induced fluorescence intensity and decay time. The Na+-selective molecule 1 was incorporated into a hydrogel as a part of a fiber optical sensor. This sensor allows the direct determination of Na+ in the range of 1-10 mM by measuring reversible fluorescence decay time changes.},
  language  = {en}
}
@misc{UnterbergLeffersHuebneretal.2014,
  author    = {Unterberg, Marlies and Leffers, Larissa and H{\"u}bner, Florian and Humpf, Hans-Ulrich and Lepikhov, Konstantin and Walter, J{\"o}rn and Ebert, Franziska and Schwerdtle, Tanja},
  title     = {Toxicity of arsenite and thio-DMAV after long-term (21 days) incubation of human urothelial cells: cytotoxicity, genotoxicity and epigenetics},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-76239},
  pages     = {456 -- 464},
  year      = {2014},
  abstract  = {This study aims to further mechanistically understand toxic modes of action after chronic inorganic arsenic exposure. Therefore long-term incubation studies in cultured cells were carried out, to display chronically attained changes, which cannot be observed in the generally applied in vitro short-term incubation studies. Particularly, the cytotoxic, genotoxic and epigenetic effects of an up to 21 days incubation of human urothelial (UROtsa) cells with pico- to nanomolar concentrations of iAsIII and its metabolite thio-DMAV were compared. After 21 days of incubation, cytotoxic effects were strongly enhanced in the case of iAsIII and might partly be due to glutathione depletion and genotoxic effects on the chromosomal level. These results are in strong contrast to cells exposed to thio-DMAV. Thus, cells seemed to be able to adapt to this arsenical, as indicated among others by an increase in the cellular glutathione level. Most interestingly, picomolar concentrations of both iAsIII and thio-DMAV caused global DNA hypomethylation in UROtsa cells, which was quantified in parallel by 5-medC immunostaining and a newly established, reliable, high resolution mass spectrometry (HRMS)-based test system. This is the first time that epigenetic effects are reported for thio-DMAV; iAsIII induced epigenetic effects occur in at least 8000 fold lower concentrations as reported in vitro before. The fact that both arsenicals cause DNA hypomethylation at really low, exposure-relevant concentrations in human urothelial cells suggests that this epigenetic effect might contribute to inorganic arsenic induced carcinogenicity, which for sure has to be further investigated in future studies.},
  language  = {en}
}
@misc{ZamponiPenfoldNachtegaaletal.2014,
  author    = {Zamponi, Flavio and Penfold, Thomas J. and Nachtegaal, Maarten and L{\"u}bcke, Andrea and Rittmann, Jochen and Milne, Chris J. and Chergui, Majed and van Bokhoven, Jeroen A.},
  title     = {Probing the dynamics of plasmon-excited hexanethiol-capped gold nanoparticles by picosecond X-ray absorption spectroscopy},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-74492},
  pages     = {23157 -- 23163},
  year      = {2014},
  abstract  = {Picosecond X-ray absorption spectroscopy (XAS) is used to investigate the electronic and structural dynamics initiated by plasmon excitation of 1.8 nm diameter Au nanoparticles (NPs) functionalised with 1-hexanethiol. We show that 100 ps after photoexcitation the transient XAS spectrum is consistent with an 8\% expansion of the Au-Au bond length and a large increase in disorder associated with melting of the NPs. Recovery of the ground state occurs with a time constant of ∼1.8 ns, arising from thermalisation with the environment. Simulations reveal that the transient spectrum exhibits no signature of charge separation at 100 ps and allows us to estimate an upper limit for the quantum yield (QY) of this process to be <0.1.},
  language  = {en}
}
@misc{WessigGerngrossPapeetal.2014,
  author    = {Wessig, Pablo and Gerngroß, Maik and Pape, Simon and Bruhns, Philipp and Weber, Jens},
  title     = {Novel porous materials based on oligospiroketals (OSK)},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-74466},
  pages     = {31123 -- 31129},
  year      = {2014},
  abstract  = {New porous materials based on covalently connected monomers are presented. The key step of the synthesis is an acetalisation reaction. In previous years we used acetalisation reactions extensively to build up various molecular rods. Based on this approach, investigations towards porous polymeric materials were conducted by us. Here we wish to present the results of these studies in the synthesis of 1D polyacetals and porous 3D polyacetals. By scrambling experiments with 1D acetals we could prove that exchange reactions occur between different building blocks (evidenced by MALDI-TOF mass spectrometry). Based on these results we synthesized porous 3D polyacetals under the same mild conditions.},
  language  = {en}
}
@misc{MetzlerJeonCherstvyetal.2014,
  author    = {Metzler, Ralf and Jeon, Jae-Hyung and Cherstvy, Andrey G. and Barkai, Eli},
  title     = {Anomalous diffusion models and their properties},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-74448},
  pages     = {24128 -- 24164},
  year      = {2014},
  abstract  = {Modern microscopic techniques following the stochastic motion of labelled tracer particles have uncovered significant deviations from the laws of Brownian motion in a variety of animate and inanimate systems. Such anomalous diffusion can have different physical origins, which can be identified from careful data analysis. In particular, single particle tracking provides the entire trajectory of the traced particle, which allows one to evaluate different observables to quantify the dynamics of the system under observation. We here provide an extensive overview over different popular anomalous diffusion models and their properties. We pay special attention to their ergodic properties, highlighting the fact that in several of these models the long time averaged mean squared displacement shows a distinct disparity to the regular, ensemble averaged mean squared displacement. In these cases, data obtained from time averages cannot be interpreted by the standard theoretical results for the ensemble averages. Here we therefore provide a comparison of the main properties of the time averaged mean squared displacement and its statistical behaviour in terms of the scatter of the amplitudes between the time averages obtained from different trajectories. We especially demonstrate how anomalous dynamics may be identified for systems, which, on first sight, appear to be Brownian. Moreover, we discuss the ergodicity breaking parameters for the different anomalous stochastic processes and showcase the physical origins for the various behaviours. This Perspective is intended as a guidebook for both experimentalists and theorists working on systems, which exhibit anomalous diffusion.},
  language  = {en}
}
@misc{EhlertUngerSaalfrank2014,
  author    = {Ehlert, Christopher and Unger, Wolfgang E. S. and Saalfrank, Peter},
  title     = {C K-edge NEXAFS spectra of graphene with physical and chemical defects},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-74429},
  pages     = {14083 -- 14095},
  year      = {2014},
  abstract  = {Recently, C K-edge Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra of graphite (HOPG) surfaces have been measured for the pristine material, and for HOPG treated with either bromine or krypton plasmas (Lippitz et al., Surf. Sci., 2013, 611, L1). Changes of the NEXAFS spectra characteristic for physical (krypton) and/or chemical/physical modifications of the surface (bromine) upon plasma treatment were observed. Their molecular origin, however, remained elusive. In this work we study by density functional theory, the effects of selected point and line defects as well as chemical modifications on NEXAFS carbon K-edge spectra of single graphene layers. For Br-treated surfaces, also Br 3d X-ray Photoelectron Spectra (XPS) are simulated by a cluster approach, to identify possible chemical modifications. We observe that some of the defects related to plasma treatment lead to characteristic changes of NEXAFS spectra, similar to those in experiment. Theory provides possible microscopic origins for these changes.},
  language  = {en}
}
@misc{WirthNeumannAntoniettietal.2014,
  author    = {Wirth, Jonas and Neumann, Rainer and Antonietti, Markus and Saalfrank, Peter},
  title     = {Adsorption and photocatalytic splitting of water on graphitic carbon nitride},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-74391},
  pages     = {15917 -- 15926},
  year      = {2014},
  abstract  = {Graphitic carbon nitride, g-C₃N₄, is a promising organic photo-catalyst for a variety of redox reactions. In order to improve its efficiency in a systematic manner, however, a fundamental understanding of the microscopic interaction between catalyst, reactants and products is crucial. Here we present a systematic study of water adsorption on g-C₃N₄ by means of density functional theory and the density functional based tight-binding method as a prerequisite for understanding photocatalytic water splitting. We then analyze this prototypical redox reaction on the basis of a thermodynamic model providing an estimate of the overpotential for both water oxidation and H⁺ reduction. While the latter is found to occur readily upon irradiation with visible light, we derive a prohibitive overpotential of 1.56 eV for the water oxidation half reaction, comparing well with the experimental finding that in contrast to H₂ production O₂ evolution is only possible in the presence of oxidation cocatalysts.},
  language  = {en}
}
@misc{PieperWeheBornhorstetal.2014,
  author    = {Pieper, Imke and Wehe, Christoph A. and Bornhorst, Julia and Ebert, Franziska and Leffers, Larissa and Holtkamp, Michael and H{\"o}seler, Pia and Weber, Till and Mangerich, Aswin and B{\"u}rkle, Alexander and Karst, Uwe and Schwerdtle, Tanja},
  title     = {Mechanisms of Hg species induced toxicity in cultured human astrocytes},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-74379},
  pages     = {662 -- 671},
  year      = {2014},
  abstract  = {The toxicologically most relevant mercury (Hg) species for human exposure is methylmercury (MeHg). Thiomersal is a common preservative used in some vaccine formulations. The aim of this study is to get further mechanistic insight into the yet not fully understood neurotoxic modes of action of organic Hg species. Mercury species investigated include MeHgCl and thiomersal. Additionally HgCl2 was studied, since in the brain mercuric Hg can be formed by dealkylation of the organic species. As a cellular system astrocytes were used. In vivo astrocytes provide the environment necessary for neuronal function. In the present study, cytotoxic effects of the respective mercuricals increased with rising alkylation level and correlated with their cellular bioavailability. Further experiments revealed for all species at subcytotoxic concentrations no induction of DNA strand breaks, whereas all species massively increased H2O2-induced DNA strand breaks. This co- genotoxic effect is likely due to a disturbance of the cellular DNA damage response. Thus, at nanomolar, sub-cytotoxic concentrations, all three mercury species strongly disturbed poly(ADP-ribosyl)ation, a signalling reaction induced by DNA strand breaks. Interestingly, the molecular mechanism behind this inhibition seems to be different for the species. Since chronic PARP-1 inhibition is also discussed to sacrifice neurogenesis and learning abilities, further experiments on neurons and in vivo studies could be helpful to clarify whether the inhibition of poly(ADP-ribosyl) ation contributes to organic Hg induced neurotoxicity.},
  language  = {en}
}
@misc{MeyerMatissekMuelleretal.2014,
  author    = {Meyer, S{\"o}ren and Matissek, M. and M{\"u}ller, Sandra Marie and Taleshi, M. S. and Ebert, Franziska and Francesconi, Kevin A. and Schwerdtle, Tanja},
  title     = {In vitro toxicological characterisation of three arsenic-containing hydrocarbons},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-74201},
  pages     = {1023 -- 1033},
  year      = {2014},
  abstract  = {Arsenic-containing hydrocarbons are one group of fat-soluble organic arsenic compounds (arsenolipids) found in marine fish and other seafood. A risk assessment of arsenolipids is urgently needed, but has not been possible because of the total lack of toxicological data. In this study the cellular toxicity of three arsenic-containing hydrocarbons was investigated in cultured human bladder (UROtsa) and liver (HepG2) cells. Cytotoxicity of the arsenic-containing hydrocarbons was comparable to that of arsenite, which was applied as the toxic reference arsenical. A large cellular accumulation of arsenic, as measured by ICP-MS/MS, was observed after incubation of both cell lines with the arsenolipids. Moreover, the toxic mode of action shown by the three arsenic-containing hydrocarbons seemed to differ from that observed for arsenite. Evidence suggests that the high cytotoxic potential of the lipophilic arsenicals results from a decrease in the cellular energy level. This first in vitro based risk assessment cannot exclude a risk to human health related to the presence of arsenolipids in seafood, and indicates the urgent need for further toxicity studies in experimental animals to fully assess this possible risk.},
  language  = {en}
}
@misc{MondalBhuniaKellingetal.2014,
  author    = {Mondal, Suvendu Sekhar and Bhunia, Asamanjoy and Kelling, Alexandra and Schilde, Uwe and Janiak, Christoph and Holdt, Hans-J{\"u}rgen},
  title     = {A supramolecular Co(II)₁₄-metal-organic cube in a hydrogen-bonded network and a Co(II)-organic framework with a flexible methoxy substituent},
  number    = {169},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-74098},
  pages     = {5441 -- 5443},
  year      = {2014},
  abstract  = {The reaction of 4,5-dicyano-2-methoxyimidazole (L1) with Co(NO3)2·6H2O under solvothermal conditions in DMF, a MOF, IFP-8 and a hydrogen-bonded network consisting of tetradecanuclear Co(II)14-metal organic cube (1) are achieved. 1 shows the bcu net with 14 cobalt atoms.},
  language  = {en}
}
@misc{CherstvyChechkinMetzler2014,
  author    = {Cherstvy, Andrey G. and Chechkin, Aleksei V. and Metzler, Ralf},
  title     = {Particle invasion, survival, and non-ergodicity in 2D diffusion processes with space-dependent diffusivity},
  number    = {168},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-74021},
  pages     = {1591 -- 1601},
  year      = {2014},
  abstract  = {We study the thermal Markovian diffusion of tracer particles in a 2D medium with spatially varying diffusivity D(r), mimicking recently measured, heterogeneous maps of the apparent diffusion coefficient in biological cells. For this heterogeneous diffusion process (HDP) we analyse the mean squared displacement (MSD) of the tracer particles, the time averaged MSD, the spatial probability density function, and the first passage time dynamics from the cell boundary to the nucleus. Moreover we examine the non-ergodic properties of this process which are important for the correct physical interpretation of time averages of observables obtained from single particle tracking experiments. From extensive computer simulations of the 2D stochastic Langevin equation we present an in-depth study of this HDP. In particular, we find that the MSDs along the radial and azimuthal directions in a circular domain obey anomalous and Brownian scaling, respectively. We demonstrate that the time averaged MSD stays linear as a function of the lag time and the system thus reveals a weak ergodicity breaking. Our results will enable one to rationalise the diffusive motion of larger tracer particles such as viruses or submicron beads in biological cells.},
  language  = {en}
}
@misc{BaldKopyraKeller2014,
  author    = {Bald, Ilko and Kopyra, Janina and Keller, Adrian},
  title     = {On the role of fluoro-substituted nucleosides in DNA radiosensitization for tumor radiation therapy},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-73412},
  pages     = {6825 -- 6829},
  year      = {2014},
  abstract  = {Gemcitabine (2′,2′-difluorocytidine) is a well-known radiosensitizer routinely applied in concomitant chemoradiotherapy. During irradiation of biological media with high-energy radiation secondary low-energy (<10 eV) electrons are produced that can directly induce chemical bond breakage in DNA by dissociative electron attachment (DEA). Here, we investigate and compare DEA to the three molecules 2′-deoxycytidine, 2′-deoxy-5-fluorocytidine, and gemcitabine. Fluorination at specific molecular sites, i.e., nucleobase or sugar moiety, is found to control electron attachment and subsequent dissociation pathways. The presence of two fluorine atoms at the sugar ring results in more efficient electron attachment to the sugar moiety and subsequent bond cleavage. For the formation of the dehydrogenated nucleobase anion, we obtain an enhancement factor of 2.8 upon fluorination of the sugar, whereas the enhancement factor is 5.5 when the nucleobase is fluorinated. The observed fragmentation reactions suggest enhanced DNA strand breakage induced by secondary electrons when gemcitabine is incorporated into DNA.},
  language  = {en}
}
@misc{JeličićFriedrichJeremićetal.2009,
  author    = {Jeličić, Aleksandra and Friedrich, Alwin and Jeremić, Katarina and Siekmeyer, Gerd and Taubert, Andreas},
  title     = {Polymer hydrogel/polybutadiene/iron oxide nanoparticle hybrid actuators for the characterization of NiTi implants},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-48589},
  year      = {2009},
  abstract  = {One of the main issues with the use of nickel titanium alloy (NiTi) implants in cardiovascular implants (stents) is that these devices must be of very high quality in order to avoid subsequent operations due to failing stents. For small stents with diameters below ca. 2 mm, however, stent characterization is not straightforward. One of the main problems is that there are virtually no methods to characterize the interior of the NiTi tubes used for fabrication of these tiny stents. The current paper reports on a robust hybrid actuator for the characterization of NiTi tubes prior to stent fabrication. The method is based on a polymer/hydrogel/magnetic nanoparticle hybrid material and allows for the determination of the inner diameter at virtually all places in the raw NiTi tubes. Knowledge of the inner structure of the raw NiTi tubes is crucial to avoid regions that are not hollow or regions that are likely to fail due to defects inside the raw tube. The actuator enables close contact of a magnetic polymer film with the inner NiTi tube surface. The magnetic signal can be detected from outside and be used for a direct mapping of the tube interior. As a result, it is possible to detect critical regions prior to expensive and slow stent fabrication processes.},
  language  = {en}
}
@misc{LiTaubert2009,
  author    = {Li, Zhonghao and Taubert, Andreas},
  title     = {Cellulose/gold nanocrystal hybrids via an ionic liquid/aqueous precipitation route},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-45046},
  year      = {2009},
  abstract  = {Injection of a mixture of HAuCl4 and cellulose dissolved in the ionic liquid (IL) 1-butyl-3-methylimidazolium chloride [Bmim]Cl into aqueous NaBH4 leads to colloidal gold nanoparticle/cellulose hybrid precipitates. This process is a model example for a very simple and generic approach towards (noble) metal/cellulose hybrids, which could find applications in sensing, sterile filtration, or as biomaterials.},
  language  = {en}
}
@misc{PeterYenesewTwinomuhwezietal.2009,
  author    = {Peter, Martin G. and Yenesew, Abiy and Twinomuhwezi, Hannington and Kabaru, Jacques M. and Akala, Hoseah M. and Kiremire, Bernard T. and Heydenreich, Matthias and Eyase, Fredrick and Waters, Norman C. and Walsh, Douglas S.},
  title     = {Antiplasmodial and larvicidal flavonoids from Derris trifoliata},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-44614},
  year      = {2009},
  abstract  = {From the dichloromethane-methanol (1:1) extract of the seed pods of Derris trifoliata, a new flavanone derivative (S)-lupinifolin 4´-methyl ether was isolated. In addition, the known flavonoids lupinifolin and rotenone were identified. The structures were determined on the basis of spectroscopic evidence. Lupinfolin showed moderate in vitro antiplasmodial activity against the D6 (chloroquine-sensitive) and W2 (chloroquineresistant) strains of Plasmodium falciparum. The different parts of this plant showed larvicidal activities against Aedes aegypti and rotenoids were identified as the active principles.},
  language  = {en}
}
@misc{PeterMuivaYenesewetal.2009,
  author    = {Peter, Martin G. and Muiva, Lois M. and Yenesew, Abiy and Derese, Solomon and Heydenreich, Matthias and Akala, Hoseah M. and Eyase, Fredrick and Waters, Norman C. and Mutai, Charles and Keriko, Joseph M. and Walsh, Douglas S.},
  title     = {Antiplasmodial β-hydroxydihydrochalcone from seedpods of Tephrosia elata},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-44437},
  year      = {2009},
  abstract  = {From the seedpods of Tephrosia elata, a new β-hydroxydihydrochalcone named (S)-elatadihydrochalcone was isolated. In addition, the known flavonoids obovatachalcone, obovatin, obovatin methyl ether and deguelin were identified. The structures were determined on the basis of spectroscopic evidence. The crude extract and the flavonoids obtained from the seedpods of this plant showed antiplasmodial activities. The literature NMR data on β-hydroxydihydrochalcones is reviewed and the identity of some of the compounds assigned β-hydroxydihydrochalcone skeleton is questioned.},
  language  = {en}
}
@misc{TsukamotoHeabelValencaetal.2008,
  author    = {Tsukamoto, Junko and Heabel, Sophie and Valenca, Gustavo P. and Peter, Martin and Franco, Telma},
  title     = {Enzymatic direct synthesis of acrylic acid esters of mono- and disaccharides},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-42652},
  year      = {2008},
  abstract  = {BACKGROUND: There is an increased need to replace materials derived from fossil sources by renewables. Sugar-cane derived carbohydrates are very abundant in Brazil and are the cheapest sugars available in the market, with more than 400 million tons of sugarcane processed in the year 2007. The objective of this work was to study the preparation of sugar acrylates from free sugars and free acrylic acid, thus avoiding the previous preparation of protected sugar derivatives, such as glycosides, or activated acrylates, such as vinyl acrylate. RESULTS: Lipase catalyzed esterification of three mono- and two disaccharides with acrylic acid, in the presence or absence of molecular sieves was investigated. The reactions were monitored by high-performance liquid chromatography (HPLC) and the products were analyzed by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. The main products are mono- and diacrylates, while higher esters are formed as minor products. The highest conversion to sugar acrylates was observed for the D-glucose and D-fructose, followed by D-xylose and D-maltose. Molecular sieves had no pronounced effect on the conversion CONCLUSIONS: A feasible method is described to produce and to characterize sugar acrylates, including those containing more than two acrylate groups. The process for production of these higher esters could potentially be optimized further to produce molecules for cross-linking in acrylate polymerization and other applications. The direct enzymatic esterification of free carbohydrates with acrylic acid is unprecedented.},
  language  = {en}
}
@misc{OliveiraJrGueddariMoerschbacheretal.2008,
  author    = {Oliveira Jr, E. N. and Gueddari, Nour E. El and Moerschbacher, Bruno M. and Peter, Martin and Franco, Telma},
  title     = {Growth of phytopathogenic fungi in the presence of partially acetylated chitooligosaccharides},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-42646},
  year      = {2008},
  abstract  = {Four phytopathogenic fungi were cultivated up to six days in media containing chitooligosaccharide mixtures differing in average DP and FA. The three different mixtures were named Q3 (which contained oligosaccharides ofDP2-DP10, withDP2-DP7 asmain components), Q2 (which contained oligosaccharides of DP2-DP12, with DP2-DP10 as main components) and Q1 (which derived from Q2 and contained oligomers of DP5-DP8 with hexamer and a heptamer as the main components). The novel aspect of this work is the description of the effect of mixtures of oligosaccharides with different and known composition on fungal growth rates. The growth rate of Alternaria alternata and Rhizopus stolonifer was initially inhibited by Q3 and Q2 at higher concentrations. Q1 had a growth stimulating effect on these two fungi. Growth of Botrytis cinerea was inhibited by Q3 and Q2, while Q1 had no effect on the growth of this fungus. Growth of Penicillium expansum was only slightly inhibited by higher concentrations of sample Q3, while Q2 and Q1 had no effect. The inhibition of growth rates or their resistance toward chitooligosaccharides correlated with the absence or presence of chitinolytic enzymes in the culture media, respectively.},
  language  = {en}
}
@misc{BringmannMutanyattaComarMaksimenkaetal.2008,
  author    = {Bringmann, Gerhard and Mutanyatta-Comar, Joan and Maksimenka, Katja and Wanjohi, John M. and Heydenreich, Matthias and Brun, Reto and M{\"u}ller, Werner E. G. and Peter, Martin and Midiwo, Jacob O. and Yenesew, Abiy},
  title     = {Joziknipholones A and B : the First Dimeric Phenylanthraquinones, from the Roots of Bulbine frutescens},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-42638},
  year      = {2008},
  abstract  = {From the roots of the African plant Bulbine frutescens (Asphodelaceae), two unprecedented novel dimeric phenylanthraquinones, named joziknipholones A and B, possessing axial and centrochirality, were isolated, together with six known compounds. Structural elucidation of the new metabolites was achieved by spectroscopic and chiroptical methods, by reductive cleavage of the central bond between the monomeric phenylanthraquinone and -anthrone portions with sodium dithionite, and by quantum chemical CD calculations. Based on the recently revised absolute axial configuration of the parent phenylanthraquinones, knipholone and knipholone anthrone, the new dimers were attributed to possess the P-configuration (i.e., with the acetyl portions below the anthraquinone plane) at both axes in the case of joziknipholone A, whereas in joziknipholone B, the knipholone part was found to be M-configured. Joziknipholones A and B are active against the chloroquine resistant strain K1 of the malaria pathogen, Plasmodium falciparum, and show moderate activity against murine leukemic lymphoma L5178y cells.},
  language  = {en}
}
@misc{SchaeferBungNest2008,
  author    = {Sch{\"a}fer-Bung, Boris and Nest, Mathias},
  title     = {Correlated dynamics of electrons with reduced two-electron density matrices},
  issn      = {1866-8372},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41774},
  year      = {2008},
  abstract  = {We present an approach to the correlated dynamics of many-electron systems. We show, that the twoelectron reduced density matrix (2RDM) can provide a suitable description of the real time evolution of a system. To achieve this, the hierarchy of equations of motion must be truncated in a practical way. Also, the computational effort, given that the 2RDM is represented by products of two-electron determinants, is discussed, and numerical model calculations are presented.},
  language  = {en}
}
@misc{BiddleRickertLandoetal.1989,
  author    = {Biddle, M. B. and Rickert, S. E. and Lando, J. B. and Laschewsky, Andr{\´e}},
  title     = {The use of the Langmuir-Blodgett technique to obtain ultra-thin polar films},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17185},
  year      = {1989},
  abstract  = {The piezoelectric and pyroelectric properties of oriented films possessing dipole moments are increasingly being used in pressure, acoustic, thermal and optical devices. The performance of these devices in many applications may be enhanced by thin-film technology.The developing Langmuir-Blodgett thin-film deposition technique offers the opportunity to obtain highly oriented and uniform organic-based films in the 10-5000 nm thickness range. Special techniques must be used, however, to assemble these molecules in such a way as to result in polar multilayer films. Several possible deposition techniques are investigated, with one resulting in a polar and pyroelectric film about 50 nm thick.},
  language  = {en}
}
@misc{TsukrukMischenkoKoeberleetal.1992,
  author    = {Tsukruk, Vladimir and Mischenko, Nikolay and K{\"o}berle, Peter and Laschewsky, Andr{\´e}},
  title     = {The structural order of some novel ionic polymers; 2. : Models of molecular packing},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17256},
  year      = {1992},
  abstract  = {The molecular packing and spatial correlations of two isomeric zwitterionic polymethacrylates and one polyacrylate analog are studied by means of X-ray analysis and conformational calculations. The analysis of the correlation functions and density distribution profiles suggest a double-layered molecular packing which is discussed for the three polymers investigated, with respect to their different chemical structures. Whereas the zwitterionic polymethacrylates studied exhibit liquid-like short-range order, the polyacrylate analog exhibits an ordered double-layered superstructure.},
  language  = {en}
}
@misc{ElbertLaschewskyRingsdorf1985,
  author    = {Elbert, R. and Laschewsky, Andr{\´e} and Ringsdorf, H.},
  title     = {Hydrophilic spacer groups in polymerizable lipids: formation of biomembrane models from bulk polymerized lipids},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17361},
  year      = {1985},
  abstract  = {A variety of polymerizable lipids containing a hydrophilic spacer group between the reactive group and the main amphiphilic structure have been synthesized. They were investigated in monolayers, liposomes, and multilayers. When the spacer concept was used, efficient decoupling of the motions of the polymeric chain and the amphiphilic side groups is achieved. Thus, the often found loss of the important fluid phases by polymerization is avoided. Polymeric monolayers of the spacer lipid, prepared either by polymerization in the monolayer or by spreading of prepolymerized lipid, exhibit nearly identical surface pressure-area diagrams. Most distinctly, the successful decoupling of the motions of the polymer main chain and the membrane forming amphiphilic side groups is demonstrated by the self-organization of bulk polymerized spacer lipids to polymeric liposomes. In addition, spacer lipids are able to build polymeric Langmuir-Blodgett multilayers. The decoupling of the polymer main chain and the membrane-forming amphiphilic side groups enables the deposition of already polymeric monolayers onto supports to form defined multilayers. If, alternatively, monomeric monolayers are deposited and polymerized on the support, defects in the layers due to structural changes during the polymerization are avoided by the flexible spacer group.},
  language  = {en}
}
@misc{LupoPrassScheunemannetal.1988,
  author    = {Lupo, Donald and Prass, Werner and Scheunemann, Ude and Laschewsky, Andr{\´e} and Ringsdorf, Helmut and Ledoux, Isabelle},
  title     = {Second-harmonic generation in Langmuir-Blodgett monolayers of stilbazium salt and phenylhydrazone dyes},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17401},
  year      = {1988},
  abstract  = {Contents: 1. INTRODUCTION 2. SYNTHESIS OF THE COMPOUNDS 3. PREPARATION AND CHARACTERIZATION OF MONOLAYERS A. Monolayer Isotherms B. Langmuir-Blodgett Monolayer Films 4. EXPERIMENTAL SETUP FOR NONLINEAR MEASUREMENTS 5. NONLINEAR OPTICAL PROPERTIES 6. DISCUSSION 7. CONCLUSION},
  language  = {en}
}
@misc{RozanskiKremerKoeberleetal.1995,
  author    = {Rozanski, Stanislaw A. and Kremer, Friedrich and K{\"o}berle, Peter and Laschewsky, Andr{\´e}},
  title     = {Relaxation and charge transport in mixtures of zwitterionic polymers and inorganic salts},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17438},
  year      = {1995},
  abstract  = {Dielectric spectroscopy is employed to analyze the molecular dynamics and the charge transport in mixtures of zwitterionic polymers of the type poly{3 [N(-methacryloyloxyalkyl)] N, [N-dimethylammonio propanesulfonate] with sodium iodide in the frequency range of 10²Hz-10(up)7 Hz and in the temperature range of 110 K-400 K. The amount of inorganic salt added varies from 0-200 mol-\% relative to the number of zwitterionic groups present in the polymer, contributing strongly to the conductivity. One relaxation process is observed whose relaxation rate depends strongly on the length of the aliphatic spacer between the polymethacrylate main chain and the zwitterionic group. Exhibiting an Arrhenius-like temperature depence with activation energy EA = 47 KJ/mol, this relaxation process is assigned to fluctuation of the quaternary ammonium groups in the side chains. At higher temperatures, the dielectric properties and the conductivity are primarily dominated by the mobile inorganic ions: conductivity strongly depends on the salt concentration, showing a pronounced electrode polarization effect. The frequency and salt concentration, dependences of the conductivity can be quantitatively described as hopping of charge carriers being subject to spatially randomly varying energy barriers. For the low-frequency regime and for the critical frequency marking the onset of the conductivity's dispersion, the Barton-Nakajima-Namikawa (BNN) relationship is fulfilled.},
  language  = {en}
}
@misc{LaschewskySchulzHanke1993,
  author    = {Laschewsky, Andr{\´e} and Schulz-Hanke, Wolfgang},
  title     = {Ring-opening metathesis polymerization of amphiphilic norbornenes functionalized with non-linear optical (NLO) chromophores},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-26917},
  year      = {1993},
  abstract  = {Contents: Potential of amphiphilic NLO polymers Ring-opening metathesis polymerization (ROMP) Properties of the polymers Monolayer properties Experimental part - Methods - Materials - Analytical data - General polymerization procedure Conclusions},
  language  = {en}
}
@misc{AntonLaschewsky1993,
  author    = {Anton, Peter and Laschewsky, Andr{\´e}},
  title     = {Zwitterionic polysoaps with reduced density of surfactant side groups},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17301},
  year      = {1993},
  abstract  = {Several zwitterionic polymers were prepared by radical homopolymerization of surfactant monomers which bear diallyl, diene or vinylcyclopropane moieties. These polymer systems were complemented by alternating copolymers of appropriate zwitterionic vinyl compounds. Thus, polymers with reduced (as compared with simple vinylic homopolymers, or statistical copolymers) and well defined density of surfactant side groups are obtained. The solubilities found for these polymers are dominated by polymer geometry rather than by the balance of hydrophilic and hydrophobic fragments, thus corroborating a main-chain spacer model proposed recently. All water-soluble polymers exhibit characteristic features of classical polysoaps, as shown by surface tension measurements and by solubilization of hydrophobic dyes. In contrast, the water-insoluble copolymers are capable to form stable monolayers at the air-water interface.},
  language  = {en}
}
@misc{AntonKoeberleLaschewsky1993,
  author    = {Anton, Peter and K{\"o}berle, Peter and Laschewsky, Andr{\´e}},
  title     = {Recent developments in the field of micellar polymers},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17263},
  year      = {1993},
  abstract  = {This article describes recent achievements in the field of micellar polymers, or polysoaps. Taking advantage of zwitterionic model polymers, systematic variations of the molecular architecture have provided an improved understanding of the relationship between the molecular structure of the polymers and their key properties such as surface activity and solubilization capacity. Useful rules are established, which take into account much of the previous data in the literature.},
  language  = {en}
}
@misc{KoeberleLaschewskyTsukruk1992,
  author    = {K{\"o}berle, Peter and Laschewsky, Andr{\´e} and Tsukruk, Vladimir},
  title     = {The structural order of some novel ionic polymers : 1. X-ray scattering studies},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17247},
  year      = {1992},
  abstract  = {A set of novel zwitterionic side-chain polyacrylates and polymethacrylates is studied by X-ray scattering. The structural order both in the short-range and long-range scale is investigated. The influence of the polymer backbone, of different locations of the ionic groups in isomeric polymers, of bound water and of added inorganic salts on the bulk structures is studied, and the observed rearrangements are analysed.},
  language  = {en}
}
@misc{AntonLaschewsky1991,
  author    = {Anton, Peter and Laschewsky, Andr{\´e}},
  title     = {Polysoaps via alternating olefin/SO2 copolymers},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17216},
  year      = {1991},
  abstract  = {Contents: Introduction Results and discussion - Monomers studied - Monomer properties - Polymerization, copolymer composition and general properties - Polymer properties in aqueous solution Conclusion Experimental part - Materials - Copolymerization with S02 (typical procedure) - Methods},
  language  = {en}
}
@misc{Laschewsky1995,
  author    = {Laschewsky, Andr{\´e}},
  title     = {Molecular concepts, self-organisation and properties of polysoaps},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-26895},
  year      = {1995},
  abstract  = {The article reviews water-soluble polymers characterized by surfactant side chains, and related amphiphilic polymers. Various synthetic approaches are presented, and rules for useful molecular architectures are given. Models for the self-organization of such polymers in water are presented comparing them with the micellization of low molecular weight surfactants. Highlighting key properties of aqueous polysoap solutions such as viscosity, surface tension and solubilization power, some structure-property relationships are established. Further, the formation of mesophases and of superstructures in bulk is addressed. Finally, the functionalization of polysoaps, and potential applications are discussed.},
  language  = {en}
}
@misc{KoeberleLaschewsky1994,
  author    = {K{\"o}berle, Peter and Laschewsky, Andr{\´e}},
  title     = {Hybrid materials from organic polymers and inorganic salts},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-26884},
  year      = {1994},
  abstract  = {The prepaparation of amorphous, homogeneous blends of zwitterionic polymers and transition metal salts was investigated. Homogeneous miscibility was achieved in many cases up to equimolar amounts of salt, depending on the anion and cation chosen. Various analytical techniques point to a solid state solution of the inorganic ions in the polymer matrix.},
  language  = {en}
}
@misc{CochinHendlingerLaschewsky1995,
  author    = {Cochin, Didier and Hendlinger, P. and Laschewsky, Andr{\´e}},
  title     = {Polysoaps with fluorocarbon hydrophobic chains},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17347},
  year      = {1995},
  abstract  = {A series of amphiphilic copolymers is prepared by copolymerization of choline methacrylate with 1,1,2,2-tetrahydroperfluorooctyl methacrylate in varying amounts. The copolymers bearing fluorocarbon chains are studied concerning their effects on viscosity, solubilization and surface activity in aqueous solution, exhibiting a general behavior characteristic for polysoaps. The results are compared with the ones obtained for an analogous series of amphiphilic copolymers bearing hydrocarbon chains.},
  language  = {en}
}
@misc{AntonLaschewskyWard1995,
  author    = {Anton, Peter and Laschewsky, Andr{\´e} and Ward, M. D.},
  title     = {Solubilization control by redox-switching of polysoaps},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17336},
  year      = {1995},
  abstract  = {Reversible changes in the self-organization of polysoaps may be induced by controlling their charge numbers via covalently bound redox moieties. This is illustrated with two viologen polysoaps, which in response to an electrochemical stimulus, change their solubility and aggregation in water, leading from homogeneously dissolved and aggregated molecules to collapsed ones and vice verse. Using the electrochemical quartz crystal microbalance (EQCM), it could be shown that the reversibility of this process is better than 95\% in 16 cycles.},
  language  = {en}
}
@misc{AntonLaschewsky1994,
  author    = {Anton, Peter and Laschewsky, Andr{\´e}},
  title     = {Solubilization by polysoaps},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17327},
  year      = {1994},
  abstract  = {The aqueous solubilization power of several series of micellar homopolymers and copolymers (polysoaps) is investigated. Using five insoluble or poorly water-soluble dyes, comparisons of the capacities are made with respect ot the influence of structural variables such as the polymer backbone, the polymer geometry, the comonomer content, and the charge of the hydrophilic group. Some guidelines for polysoap structures suited for efficient solubilization are established. Noteworthy is that the solubilization capacities of the polysoaps are neither linked to the ability to reduce the surface tension of water, nor to the polarity of the solubilization sites deduced from spectroscopic probes.},
  language  = {en}
}
@misc{BubeckLaschewskyLupoetal.1991,
  author    = {Bubeck, Christoph and Laschewsky, Andr{\´e} and Lupo, Donald and Neher, Dieter and Ottenbreit, Petra and Paulus, Wolfgang and Prass, Werner and Ringsdorf, Helmut and Wegner, Gerhard},
  title     = {Amphiphilic dyes for nonlinear optics: Dependence of second harmonic generation on functional group substitution},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17201},
  year      = {1991},
  language  = {en}
}
@misc{EmbsFunhoffLaschewskyetal.1991,
  author    = {Embs, Frank and Funhoff, Dirk and Laschewsky, Andr{\´e} and Licht, Ulrike and Ohst, Holger and Prass, Werner and Ringsdorf, Helmut and Wegner, Gerhard and Wehrmann, Rolf},
  title     = {Preformed polymers for Langmuir-Blodgett films- molecular concepts},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17196},
  year      = {1991},
  abstract  = {The use of preformed polymers for the preparation of Langmuir-Blodgett (LB) multilayers is reviewed. Principles for polymer self-organization are outlined and the appropriate molecular designs are discussed. Recent developments in the different classes of polymers for LB multilayers are presented, and their outstanding properties highlighted.},
  language  = {en}
}
@misc{ErdelenLaschewskyRingsdorfetal.1989,
  author    = {Erdelen, C. and Laschewsky, Andr{\´e} and Ringsdorf, H. and Schneider, J. and Schuster, A.},
  title     = {Thermal behaviour of polymeric Langmuir-Blodgett multilayers},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17378},
  year      = {1989},
  abstract  = {Langmuir-Blodgett multilayers of hydrocarbon and fluorocarbon polymers with hydrophilic spacer, lipid-polyelectrolyte complexes and mesogenic polymers have been prepared. The thermal behaviour of the multilayers was studied by small angle X-ray scattering, IR and UV—visible spectroscopy. Good thermal stabilities were found for the various classes of polymers. In addition, for both complexed multilayers and mesogenic polymer films, reorientation processes were observed.},
  language  = {en}
}