@misc{HildebrandLaschewskyWischerhoff2015,
  author    = {Hildebrand, Viet and Laschewsky, Andr{\´e} and Wischerhoff, Erik},
  title     = {Modulating the solubility of zwitterionic poly((3- methacrylamidopropyl)ammonioalkane sulfonate)s in water and aqueous salt solutions via the spacer group separating the cationic and the anionic moieties},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-103040},
  pages     = {731 -- 740},
  year      = {2015},
  abstract  = {Complementary to the well-established zwitterionic monomer 3-((3-methacrylamidopropyl)dimethylammonio) propane-1-sulfonate (SPP), the closely related monomers 2-hydroxy-3-((3-methacrylamidopropyl) dimethylammonio)propane-1-sulfonate (SHPP) and 4-((3-methacrylamidopropyl)dimethylammonio)-butane-1-sulfonate (SBP) were synthesised and polymerised by reversible addition-fragmentation chain transfer (RAFT) polymerisation, using a fluorophore labeled RAFT agent. The polyzwitterions of systematically varied molar masses were characterised with respect to their solubility in water and aqueous salt solutions. Both poly(sulfobetaine)s show thermoresponsive behaviour in water, exhibiting phase separation at low temperatures and upper critical solution temperatures (UCST). For both polySHPP and polySBP, cloud points depend notably on the molar mass, and are much higher in D2O than in H2O. Also, the cloud points are effectively modulated by the addition of salts. The individual effects can be in parts correlated to the Hofmeister series for the anions studied. Still, they depend in a complex way on the concentration and the nature of the added electrolytes, on the one hand, and on the detailed nature of the spacer group separating the anionic and the cationic charges of the betaine moiety, on the other hand. As anticipated, the cloud points of polySBP are much higher than the ones of the analogous polySPP of identical molar mass. Surprisingly, the cloud points of polySHPP are also somewhat higher than the ones of their polySPP analogues, despite the additional hydrophilic hydroxyl group present in the spacer separating the ammonium and the sulfonate moieties. These findings point to a complicated interplay of the various hydrophilic components in polyzwitterions with respect to their overall hydrophilicity. Thus, the spacer group in the betaine moiety proves to be an effective additional molecular design parameter, apparently small variations of which strongly influence the phase behaviour of the polyzwitterions in specific aqueous environments.},
  language  = {en}
}
@misc{PapeWessigBrunner2015,
  author    = {Pape, Simon and Wessig, Pablo and Brunner, Heiko},
  title     = {A new and environmentally benign synthesis of aroylguanidines using iron trichloride},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-102720},
  pages     = {101408 -- 101411},
  year      = {2015},
  abstract  = {A new synthetic approach for the guanylation of aroylthioureas using iron trichloride is presented. Our synthetic method distinguishes itself by benign reaction conditions, low costs and a broad product spectrum. The scope of the reaction and calorimetric studies are described.},
  language  = {en}
}
@misc{VacogneSchlaad2015,
  author    = {Vacogne, Charlotte D. and Schlaad, Helmut},
  title     = {Primary ammonium/tertiary amine-mediated controlled ring opening polymerisation of amino acid N-carboxyanhydrides},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-102718},
  pages     = {15645 -- 15648},
  year      = {2015},
  abstract  = {Stable commercial primary ammonium chlorides were combined with tertiary amines to initiate the controlled ring opening polymerisation of amino acid N-carboxyanhydrides to yield polypeptides with defined end group structure, predetermined molar mass and narrow molar mass distribution.},
  language  = {en}
}
@misc{TasiorBaldDeperasińskaetal.2015,
  author    = {Tasior, Mariusz and Bald, Ilko and Deperasińska, Irena and Cywiński, Piotr J. and Gryko, Daniel T.},
  title     = {An internal charge transfer-dependent solvent effect in V-shaped azacyanines},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-102704},
  pages     = {11714 -- 11720},
  year      = {2015},
  abstract  = {New V-shaped non-centrosymmetric dyes, possessing a strongly electron-deficient azacyanine core, have been synthesized based on a straightforward two-step approach. The key step in this synthesis involves palladium-catalysed cross-coupling of dibromo-N,N′-methylene-2,2′-azapyridinocyanines with arylacetylenes. The resulting strongly polarized π-expanded heterocycles exhibit green to orange fluorescence and they strongly respond to changes in solvent polarity. We demonstrate that differently electron-donating peripheral groups have a significant influence on the internal charge transfer, hence on the solvent effect and fluorescence quantum yield. TD-DFT calculations confirm that, in contrast to the previously studied bis(styryl)azacyanines, the proximity of S1 and T2 states calculated for compounds bearing two 4-N,N-dimethylaminophenylethynyl moieties establishes good conditions for efficient intersystem crossing and is responsible for its low fluorescence quantum yield. Non-linear properties have also been determined for new azacyanines and the results show that depending on peripheral groups, the synthesized dyes exhibit small to large two-photon absorption cross sections reaching 4000 GM.},
  language  = {en}
}
@misc{KumkeKlier2015,
  author    = {Kumke, Michael Uwe and Klier, Dennis Tobias},
  title     = {Upconversion NaYF4:Yb:Er nanoparticles co-doped with Gd3+ and Nd3+ for thermometry on the nanoscale},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-102677},
  pages     = {67149 -- 67156},
  year      = {2015},
  abstract  = {In the present work, the upconversion luminescence properties of oleic acid capped NaYF4:Gd3+:Yb3+:Er3+ upconversion nanoparticles (UCNP) with pure β crystal phase and Nd3+ ions as an additional sensitizer were studied in the temperature range of 288 K < T < 328 K. The results of this study showed that the complex interplay of different mechanisms and effects, causing the special temperature behavior of the UCNP can be developed into thermometry on the nanoscale, e.g. to be applied in biological systems on a cellular level. The performance was improved by the use of Nd3+ as an additional dopant utilizing the cascade sensitization mechanism in tri-doped UCNP.},
  language  = {en}
}
@misc{VacogneBrosnanMasicetal.2015,
  author    = {Vacogne, Charlotte D. and Brosnan, Sarah M. and Masic, Admir and Schlaad, Helmut},
  title     = {Fibrillar gels via the self-assembly of poly(L-glutamate)-based statistical copolymers},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-102289},
  pages     = {5040 -- 5052},
  year      = {2015},
  abstract  = {Polypeptides having secondary structures often undergo self-assembly which can extend over multiple length scales. Poly(γ-benzyl-L-glutamate) (PBLG), for example, folds into α-helices and forms physical organogels, whereas poly(L-glutamic acid) (PLGA at acidic pH) or poly(L-glutamate) (PLG at neutral/basic pH) do not form hydrogels. We explored the gelation of modified PBLG and investigated the deprotection of the carboxylic acid moieties in such gels to yield unique hydrogels. This was accomplished through photo-crosslinking gelation of poly(γ-benzyl-L-glutamate-co-allylglycine) statistical copolymers in toluene, tetrahydrofuran, and 1,4-dioxane. Unlike most polymer-based chemical gels, our gels were prepared from dilute solutions (<20 g L-1, i.e., <2\% w/v) of low molar mass polymers. Despite such low concentrations and molar masses, our dioxane gels showed high mechanical stability and little shrinkage; remarkably, they also exhibited a porous fibrillar network. Deprotection of the carboxylic acid moieties in dioxane gels yielded pH responsive and highly absorbent PLGA/PLG-based hydrogels (swelling ratio of up to 87), while preserving the network structure, which is an unprecedented feature in the context of crosslinked PLGA gels. These outstanding properties are highly attractive for biomedical materials.},
  language  = {en}
}
@misc{MondalMarquardtJaniaketal.2015,
  author    = {Mondal, Suvendu Sekhar and Marquardt, Dorothea and Janiak, Christoph and Holdt, Hans-J{\"u}rgen},
  title     = {Use of a 4,5-dicyanoimidazolate anion based ionic liquid for the synthesis of iron and silver nanoparticles},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-89696},
  pages     = {5476 -- 5483},
  year      = {2015},
  abstract  = {Sixteen new ionic liquids (ILs) with tetraethylammonium, 1-butyl-3-methylimidazolium, 3-methyl-1-octylimidazolium and tetrabutylphosphonium cations paired with 2-substituted 4,5-dicyanoimidazolate anions (substituent at C2 = methyl, trifluoromethyl, pentafluoroethyl, N,N′-dimethyl amino and nitro) have been synthesized and characterized by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA). The effects of cation and anion type and structure of the resulting ILs, including several room temperature ionic liquids (RTILs), are reflected in the crystallization, melting points and thermal decomposition of the ILs. ILs exhibited large liquid and crystallization ranges and formed glasses on cooling with glass transition temperatures in the range of -22 to -71 °C. We selected one of the newly designed ILs due to its bigger size, compared to the common conventional IL anion and high electron-withdrawing nitrile group leads to an overall stabilization anion that may stabilize the metal nanoparticles. Stable and better separated iron and silver nanoparticles are obtained by the decomposition of corresponding Fe2(CO)9 and AgPF6, respectively, under N2-atmosphere in newly designed nitrile functionalized 4,5-dicyanoimidazolate anion based IL. Very small and uniform size for Fe-nanoparticles of about 1.8 ± 0.6 nm were achieved without any additional stabilizers or capping molecules. Comparatively bigger size of Ag-nanoparticles was obtained through the reduction of AgPF6 by hydrogen gas. Additionally, the AgPF6 precursor was decomposed under microwave irradiation (MWI), fabricating nut-in-shell-like, that is, core-separated-from-shell Ag-nano-structures.},
  language  = {en}
}
@misc{KlaperWessigLinker2015,
  author    = {Klaper, M. and Wessig, Pablo and Linker, Torsten},
  title     = {Base catalysed decomposition of anthracene endoperoxide},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-89676},
  pages     = {1210 -- 1213},
  year      = {2015},
  abstract  = {Catalytic amounts of a weak base are sufficient to induce the decomposition of anthracene endoperoxides to anthraquinone. The mechanism has been elucidated by isolation of intermediates in combination with DFT calculations. The whole process is suitable for the convenient generation of hydrogen peroxide under very mild conditions.},
  language  = {en}
}
@misc{PrestelMoeller2015,
  author    = {Prestel, Andreas and M{\"o}ller, Heiko Michael},
  title     = {Spatio-temporal control of cellular uptake achieved by photoswitchable cell-penetrating peptides},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-89658},
  pages     = {701 -- 704},
  year      = {2015},
  abstract  = {The selective uptake of compounds into specific cells of interest is a major objective in cell biology and drug delivery. By incorporation of a novel, thermostable azobenzene moiety we generated peptides that can be switched optically between an inactive state and an active, cell-penetrating state with excellent spatio-temporal control.},
  language  = {en}
}
@misc{KlierKumke2015,
  author    = {Klier, Dennis Tobias and Kumke, Michael Uwe},
  title     = {Analysing the effect of the crystal structure on upconversion luminescence in Yb3+,Er3+-co-doped NaYF4 nanomaterials},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-89630},
  pages     = {11228 -- 11238},
  year      = {2015},
  abstract  = {NaYF4:Yb:Er nanoparticles (UCNP) were synthesized under mild experimental conditions to obtain a pure cubic lattice. Upon annealing at different temperatures up to Tan = 700 °C phase transitions to the hexagonal phase and back to the cubic phase were induced. The UCNP materials obtained for different Tan were characterized with respect to the lattice phase using standard XRD and Raman spectroscopy as well as steady state and time resolved upconversion luminescence. The standard techniques showed that for the annealing temperature range 300 °C < Tan < 600 °C the hexagonal lattice phase was dominant. For Tan < 300 °C hardly any change in the lattice phase could be deduced, whereas for Tan > 600 °C a back transfer to the α-phase was observed. Complementarily, the luminescence upconversion properties of the annealed UCNP materials were characterized in steady state and time resolved luminescence measurements. Distinct differences in the upconversion luminescence intensity, the spectral intensity distribution and the luminescence decay kinetics were found for the cubic and hexagonal lattice phases, respectively, corroborating the results of the standard analytical techniques used. In laser power dependent measurements of the upconversion luminescence intensity it was found that the green (G1, G2) and red (R) emission of Er3+ showed different effects of Tan on the number of required photons reflecting the differences in the population routes of different energy levels involved. Furthermore, the intensity ratio of Gfull/R is highly effected by the laser power only when the β-phase is present, whereas the G1/G2 intensity ratio is only slightly effected regardless of the crystal phase. Moreover, based on different upconversion luminescence kinetics characteristics of the cubic and hexagonal phase time-resolved area normalized emission spectra (TRANES) proved to be a very sensitive tool to monitor the phase transition between cubic and hexagonal phases. Based on the TRANES analysis it was possible to resolve the lattice phase transition in more detail for 200 °C < Tan < 300 °C, which was not possible with the standard techniques.},
  language  = {en}
}
@misc{KlierKumke2015,
  author    = {Klier, Dennis Tobias and Kumke, Michael Uwe},
  title     = {Upconversion NaYF4:Yb:Er nanoparticles co-doped with Gd3+ and Nd3+ for thermometry on the nanoscale},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-89618},
  pages     = {67149 -- 67156},
  year      = {2015},
  abstract  = {In the present work, the upconversion luminescence properties of oleic acid capped NaYF4:Gd3+:Yb3+:Er3+ upconversion nanoparticles (UCNP) with pure β crystal phase and Nd3+ ions as an additional sensitizer were studied in the temperature range of 288 K < T < 328 K. The results of this study showed that the complex interplay of different mechanisms and effects, causing the special temperature behavior of the UCNP can be developed into thermometry on the nanoscale, e.g. to be applied in biological systems on a cellular level. The performance was improved by the use of Nd3+ as an additional dopant utilizing the cascade sensitization mechanism in tri-doped UCNP.},
  language  = {en}
}
@misc{MatisSchoenbornSaalfrank2015,
  author    = {Matis, Jochen Ren{\´e} and Sch{\"o}nborn, Jan Boyke and Saalfrank, Peter},
  title     = {A multi-reference study of the byproduct formation for a ring-closed dithienylethene photoswitch},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-89594},
  pages     = {14088 -- 14095},
  year      = {2015},
  abstract  = {Photodriven molecular switches are sometimes hindered in their performance by forming byproducts which act as dead ends in sequences of switching cycles, leading to rapid fatigue effects. Understanding the reaction pathways to unwanted byproducts is a prerequisite for preventing them. This article presents a study of the photochemical reaction pathways for byproduct formation in the photochromic switch 1,2-bis-(3-thienyl)-ethene. Specifically, using single- and multi-reference methods the post-deexcitation reaction towards the byproduct in the electronic ground state S0 when starting from the S1-S0 conical intersection (CoIn), is considered in detail. We find an unusual low-energy pathway, which offers the possibility for the formation of a dyotropic byproduct. Several high-energy pathways can be excluded with high probability.},
  language  = {en}
}
@misc{deCarvalhoMetzlerCherstvy2015,
  author    = {de Carvalho, Sidney J. and Metzler, Ralf and Cherstvy, Andrey G.},
  title     = {Inverted critical adsorption of polyelectrolytes in confinement},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-89562},
  pages     = {4430 -- 4443},
  year      = {2015},
  abstract  = {What are the fundamental laws for the adsorption of charged polymers onto oppositely charged surfaces, for convex, planar, and concave geometries? This question is at the heart of surface coating applications, various complex formation phenomena, as well as in the context of cellular and viral biophysics. It has been a long-standing challenge in theoretical polymer physics; for realistic systems the quantitative understanding is however often achievable only by computer simulations. In this study, we present the findings of such extensive Monte-Carlo in silico experiments for polymer-surface adsorption in confined domains. We study the inverted critical adsorption of finite-length polyelectrolytes in three fundamental geometries: planar slit, cylindrical pore, and spherical cavity. The scaling relations extracted from simulations for the critical surface charge density sc—defining the adsorption-desorption transition—are in excellent agreement with our analytical calculations based on the ground-state analysis of the Edwards equation. In particular, we confirm the magnitude and scaling of sc for the concave interfaces versus the Debye screening length 1/k and the extent of confinement a for these three interfaces for small ka values. For large ka the critical adsorption condition approaches the known planar limit. The transition between the two regimes takes place when the radius of surface curvature or half of the slit thickness a is of the order of 1/k. We also rationalize how sc(k) dependence gets modified for semi-flexible versus flexible chains under external confinement. We examine the implications of the chain length for critical adsorption—the effect often hard to tackle theoretically—putting an emphasis on polymers inside attractive spherical cavities. The applications of our findings to some biological systems are discussed, for instance the adsorption of nucleic acids onto the inner surfaces of cylindrical and spherical viral capsids.},
  language  = {en}
}
@misc{HentrichJungingerBrunsetal.2015,
  author    = {Hentrich, Doreen and Junginger, Mathias and Bruns, Michael and B{\"o}rner, Hans Gerhard and Brandt, Jessica and Brezesinski, Gerald and Taubert, Andreas},
  title     = {Interface-controlled calcium phosphate mineralization},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-89540},
  pages     = {6901 -- 6913},
  year      = {2015},
  abstract  = {The phase behavior of an amphiphilic block copolymer based on a poly(aspartic acid) hydrophilic block and a poly(n-butyl acrylate) hydrophobic block was investigated at the air-water and air-buffer interface. The polymer forms stable monomolecular films on both subphases. At low pH, the isotherms exhibit a plateau. Compression-expansion experiments and infrared reflection absorption spectroscopy suggest that the plateau is likely due to the formation of polymer bi- or multilayers. At high pH the films remain intact upon compression and no multilayer formation is observed. Furthermore, the mineralization of calcium phosphate beneath the monolayer was studied at different pH. The pH of the subphase and thus the polymer charge strongly affects the phase behavior of the film and the mineral formation. After 4 h of mineralization at low pH, atomic force microscopy shows smooth mineral films with a low roughness. With increasing pH the mineral films become inhomogeneous and the roughness increases. Transmission electron microscopy confirms this: at low pH a few small but uniform particles form whereas particles grown at higher pH are larger and highly agglomerated. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirm the formation of calcium phosphate. The levels of mineralization are higher in samples grown at high pH.},
  language  = {en}
}
@misc{BanerjeeStuekerSaalfrank2015,
  author    = {Banerjee, Shiladitya and St{\"u}ker, Tony and Saalfrank, Peter},
  title     = {Vibrationally resolved optical spectra of modified diamondoids obtained from time-dependent correlation function methods},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-86826},
  year      = {2015},
  abstract  = {Optical properties of modified diamondoids have been studied theoretically using vibrationally resolved electronic absorption, emission and resonance Raman spectra. A time-dependent correlation function approach has been used for electronic two-state models, comprising a ground state (g) and a bright, excited state (e), the latter determined from linear-response, time-dependent density functional theory (TD-DFT). The harmonic and Condon approximations were adopted. In most cases origin shifts, frequency alteration and Duschinsky rotation in excited states were considered. For other cases where no excited state geometry optimization and normal mode analysis were possible or desired, a short-time approximation was used. The optical properties and spectra have been computed for (i) a set of recently synthesized sp2/sp3 hybrid species with C[double bond, length as m-dash]C double-bond connected saturated diamondoid subunits, (ii) functionalized (mostly by thiol or thione groups) diamondoids and (iii) urotropine and other C-substituted diamondoids. The ultimate goal is to tailor optical and electronic features of diamondoids by electronic blending, functionalization and substitution, based on a molecular-level understanding of the ongoing photophysics.},
  language  = {en}
}
@misc{RoderHille2015,
  author    = {Roder, Phillip and Hille, Carsten},
  title     = {A Multifunctional Frontloading Approach for Repeated Recycling of a Pressure-Controlled AFM Micropipette},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-86592},
  year      = {2015},
  abstract  = {Fluid force microscopy combines the positional accuracy and force sensitivity of an atomic force microscope (AFM) with nanofluidics via a microchanneled cantilever. However, adequate loading and cleaning procedures for such AFM micropipettes are required for various application situations. Here, a new frontloading procedure is described for an AFM micropipette functioning as a force- and pressure-controlled microscale liquid dispenser. This frontloading procedure seems especially attractive when using target substances featuring high costs or low available amounts. Here, the AFM micropipette could be filled from the tip side with liquid from a previously applied droplet with a volume of only a few μL using a short low-pressure pulse. The liquid-loaded AFM micropipettes could be then applied for experiments in air or liquid environments. AFM micropipette frontloading was evaluated with the well-known organic fluorescent dye rhodamine 6G and the AlexaFluor647-labeled antibody goat anti-rat IgG as an example of a larger biological compound. After micropipette usage, specific cleaning procedures were tested. Furthermore, a storage method is described, at which the AFM micropipettes could be stored for a few hours up to several days without drying out or clogging of the microchannel. In summary, the rapid, versatile and cost-efficient frontloading and cleaning procedure for the repeated usage of a single AFM micropipette is beneficial for various application situations from specific surface modifications through to local manipulation of living cells, and provides a simplified and faster handling for already known experiments with fluid force microscopy.},
  language  = {en}
}
@misc{BodrovaChechkinCherstvyetal.2015,
  author    = {Bodrova, Anna and Chechkin, Aleksei V. and Cherstvy, Andrey G. and Metzler, Ralf},
  title     = {Quantifying non-ergodic dynamics of force-free granular gases},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-85200},
  year      = {2015},
  abstract  = {Brownianmotion is ergodic in the Boltzmann-Khinchin sense that long time averages of physical observables such as the mean squared displacement provide the same information as the corresponding ensemble average, even at out-of-equilibrium conditions. This property is the fundamental prerequisite for single particle tracking and its analysis in simple liquids. We study analytically and by event-driven molecular dynamics simulations the dynamics of force-free cooling granular gases and reveal a violation of ergodicity in this Boltzmann-Khinchin sense as well as distinct ageing of the system. Such granular gases comprise materials such as dilute gases of stones, sand, various types of powders, or large molecules, and their mixtures are ubiquitous in Nature and technology, in particular in Space. We treat—depending on the physical-chemical properties of the inter-particle interaction upon their pair collisions—both a constant and a velocity-dependent (viscoelastic) restitution coefficient e. Moreover we compare the granular gas dynamics with an effective single particle stochastic model based on an underdamped Langevin equation with time dependent diffusivity. We find that both models share the same behaviour of the ensemble mean squared displacement (MSD) and the velocity correlations in the limit of weak dissipation. Qualitatively, the reported non-ergodic behaviour is generic for granular gases with any realistic dependence of e on the impact velocity of particles.},
  language  = {en}
}
@misc{MaiBoyeYuanetal.2015,
  author    = {Mai, Tobias and Boye, Susanne and Yuan, Jiayin and V{\"o}lkel, Antje and Gr{\"a}wert, Marlies and G{\"u}nter, Christina and Lederer, Albena and Taubert, Andreas},
  title     = {Poly(ethylene oxide)-based block copolymers with very high molecular weights for biomimetic calcium phosphate mineralization},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-85299},
  year      = {2015},
  abstract  = {The present article is among the first reports on the effects of poly(ampholyte)s and poly(betaine)s on the biomimetic formation of calcium phosphate. We have synthesized a series of di- and triblock copolymers based on a non-ionic poly(ethylene oxide) block and several charged methacrylate monomers, 2-(trimethylammonium)ethyl methacrylate chloride, 2-((3-cyanopropyl)-dimethylammonium)ethyl methacrylate chloride, 3-sulfopropyl methacrylate potassium salt, and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide. The resulting copolymers are either positively charged, ampholytic, or betaine block copolymers. All the polymers have very high molecular weights of over 106 g mol-1. All polymers are water-soluble and show a strong effect on the precipitation and dissolution of calcium phosphate. The strongest effects are observed with triblock copolymers based on a large poly(ethylene oxide) middle block (nominal Mn = 100 000 g mol-1). Surprisingly, the data show that there is a need for positive charges in the polymers to exert tight control over mineralization and dissolution, but that the exact position of the charge in the polymer is of minor importance for both calcium phosphate precipitation and dissolution.},
  language  = {en}
}
@misc{MardoukhiJeonMetzler2015,
  author    = {Mardoukhi, Yousof and Jeon, Jae-Hyung and Metzler, Ralf},
  title     = {Geometry controlled anomalous diffusion in random fractal geometries},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-85247},
  year      = {2015},
  abstract  = {We investigate the ergodic properties of a random walker performing (anomalous) diffusion on a random fractal geometry. Extensive Monte Carlo simulations of the motion of tracer particles on an ensemble of realisations of percolation clusters are performed for a wide range of percolation densities. Single trajectories of the tracer motion are analysed to quantify the time averaged mean squared displacement (MSD) and to compare this with the ensemble averaged MSD of the particle motion. Other complementary physical observables associated with ergodicity are studied, as well. It turns out that the time averaged MSD of individual realisations exhibits non-vanishing fluctuations even in the limit of very long observation times as the percolation density approaches the critical value. This apparent non-ergodic behaviour concurs with the ergodic behaviour on the ensemble averaged level. We demonstrate how the non-vanishing fluctuations in single particle trajectories are analytically expressed in terms of the fractal dimension and the cluster size distribution of the random geometry, thus being of purely geometrical origin. Moreover, we reveal that the convergence scaling law to ergodicity, which is known to be inversely proportional to the observation time T for ergodic diffusion processes, follows a power-law BT� h with h o 1 due to the fractal structure of the accessible space. These results provide useful measures for differentiating the subdiffusion on random fractals from an otherwise closely related process, namely, fractional Brownian motion. Implications of our results on the analysis of single particle tracking experiments are provided.},
  language  = {en}
}
@misc{JahnBuschmannHille2015,
  author    = {Jahn, Karolina and Buschmann, Volker and Hille, Carsten},
  title     = {Simultaneous Fluorescence and Phosphorescence Lifetime Imaging Microscopy in Living Cells},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82156},
  year      = {2015},
  abstract  = {In living cells, there are always a plethora of processes taking place at the same time. Their precise regulation is the basis of cellular functions, since small failures can lead to severe dysfunctions. For a comprehensive understanding of intracellular homeostasis, simultaneous multiparameter detection is a versatile tool for revealing the spatial and temporal interactions of intracellular parameters. Here, a recently developed time-correlated single-photon counting (TCSPC) board was evaluated for simultaneous fluorescence and phosphorescence lifetime imaging microscopy (FLIM/PLIM). Therefore, the metabolic activity in insect salivary glands was investigated by recording ns-decaying intrinsic cellular fluorescence, mainly related to oxidized flavin adenine dinucleotide (FAD) and the μs-decaying phosphorescence of the oxygen-sensitive ruthenium-complex Kr341. Due to dopamine stimulation, the metabolic activity of salivary glands increased, causing a higher pericellular oxygen consumption and a resulting increase in Kr341 phosphorescence decay time. Furthermore, FAD fluorescence decay time decreased, presumably due to protein binding, thus inducing a quenching of FAD fluorescence decay time. Through application of the metabolic drugs antimycin and FCCP, the recorded signals could be assigned to a mitochondrial origin. The dopamine-induced changes could be observed in sequential FLIM and PLIM recordings, as well as in simultaneous FLIM/PLIM recordings using an intermediate TCSPC timing resolution.},
  language  = {en}
}