@article{ParkWaltaRosencrantzetal.2016, author = {Park, H. and Walta, S. and Rosencrantz, Ruben R. and Koerner, A. and Schulte, Christoph and Elling, L. and Richtering, Walter and B{\"o}ker, Alexander}, title = {Micelles from self-assembled double-hydrophilic PHEMA-glycopolymer-diblock copolymers as multivalent scaffolds for lectin binding}, series = {Polymer Chemistry}, volume = {7}, journal = {Polymer Chemistry}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1759-9954}, doi = {10.1039/c5py00797f}, pages = {878 -- 886}, year = {2016}, abstract = {We introduce a novel double-hydrophilic hydroxyethylmethacrylate (HEMA) based diblock glycopolymer which self-assembles into homogeneous spherical micellar structures in water. The micellar structure renders surface-oriented N-acetylglucocosamine (GlcNAc) sugar moieties for strong multivalent glycan-mediated lectin binding. Structural analysis and lectin binding is performed by microscopy methods, dynamic light scattering (DLS) and two-focus fluorescence correlation spectroscopy (2fFCS), revealing a novel micellar type of multivalent sugar binding scaffold with high potential for biomedical applications.}, language = {en} } @article{WirthKirschWlosczyketal.2016, author = {Wirth, Jonas and Kirsch, Harald and Wlosczyk, Sebastian and Tong, Yujin and Saalfrank, Peter and Campen, Richard Kramer}, title = {Characterization of water dissociation on alpha-Al2O3(1(1)over-bar02): theory and experiment}, series = {Physical chemistry, chemical physics : a journal of European Chemical Societies}, volume = {18}, journal = {Physical chemistry, chemical physics : a journal of European Chemical Societies}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1463-9076}, doi = {10.1039/c6cp01397j}, pages = {14822 -- 14832}, year = {2016}, abstract = {The interaction of water with a-alumina (i.e. alpha-Al2O3) surfaces is important in a variety of applications and a useful model for the interaction of water with environmentally abundant aluminosilicate phases. Despite its significance, studies of water interaction with alpha-Al2O3 surfaces other than the (0001) are extremely limited. Here we characterize the interaction of water (D2O) with a well defined alpha-Al2O3(1 (1) over bar 02) surface in UHV both experimentally, using temperature programmed desorption and surface-specific vibrational spectroscopy, and theoretically, using periodic-slab density functional theory calculations. This combined approach makes it possible to demonstrate that water adsorption occurs only at a single well defined surface site (the so-called 1-4 configuration) and that at this site the barrier between the molecularly and dissociatively adsorbed forms is very low: 0.06 eV. A subset of OD stretch vibrations are parallel to this dissociation coordinate, and thus would be expected to be shifted to low frequencies relative to an uncoupled harmonic oscillator. To quantify this effect we solve the vibrational Schrodinger equation along the dissociation coordinate and find fundamental frequencies red-shifted by more than 1500 cm(-1). Within the context of this model, at moderate temperatures, we further find that some fraction of surface deuterons are likely delocalized: dissociatively and molecularly absorbed states are no longer distinguishable.}, language = {en} } @article{OertelKellerPrinzetal.2016, author = {Oertel, Jana and Keller, Adrian and Prinz, Julia and Schreiber, Benjamin and Huebner, Rene and Kerbusch, Jochen and Bald, Ilko and Fahmy, Karim}, title = {Anisotropic metal growth on phospholipid nanodiscs via lipid bilayer expansion}, series = {Scientific reports}, volume = {6}, journal = {Scientific reports}, publisher = {Nature Publ. Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep26718}, pages = {9}, year = {2016}, abstract = {Self-assembling biomolecules provide attractive templates for the preparation of metallic nanostructures. However, the intuitive transfer of the "outer shape" of the assembled macromolecules to the final metallic particle depends on the intermolecular forces among the biomolecules which compete with interactions between template molecules and the metal during metallization. The shape of the bio-template may thus be more dynamic than generally assumed. Here, we have studied the metallization of phospholipid nanodiscs which are discoidal particles of similar to 10 nm diameter containing a lipid bilayer similar to 5 nm thick. Using negatively charged lipids, electrostatic adsorption of amine-coated Au nanoparticles was achieved and followed by electroless gold deposition. Whereas Au nanoparticle adsorption preserves the shape of the bio-template, metallization proceeds via invasion of Au into the hydrophobic core of the nanodisc. Thereby, the lipidic phase induces a lateral growth that increases the diameter but not the original thickness of the template. Infrared spectroscopy reveals lipid expansion and suggests the existence of internal gaps in the metallized nanodiscs, which is confirmed by surface-enhanced Raman scattering from the encapsulated lipids. Interference of metallic growth with non-covalent interactions can thus become itself a shape-determining factor in the metallization of particularly soft and structurally anisotropic biomaterials.}, language = {en} } @article{KyriakosPhilippLinetal.2016, author = {Kyriakos, Konstantinos and Philipp, Martine and Lin, Che-Hung and Dyakonova, Margarita and Vishnevetskaya, Natalya and Grillo, Isabelle and Zaccone, Alessio and Miasnikova, Anna and Laschewsky, Andre and M{\"u}ller-Buschbaum, Peter and Papadakis, Christine M.}, title = {Quantifying the Interactions in the Aggregation of Thermoresponsive Polymers: The Effect of Cononsolvency}, series = {Macromolecular rapid communications}, volume = {37}, journal = {Macromolecular rapid communications}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1022-1336}, doi = {10.1002/marc.201500583}, pages = {420 -- 425}, year = {2016}, abstract = {The aggregation kinetics of thermoresponsive core-shell micelles with a poly(N-isopropyl acrylamide) shell in pure water or in mixtures of water with the cosolvents methanol or ethanol at mole fractions of 5\% is investigated during a temperature jump across the respective cloud point. Characteristically, these mixtures give rise to cononsolvency behavior. At the cloud point, aggregates are formed, and their growth is followed with time-resolved small-angle neutron scattering. Using the reversible association model, the interaction potential between the aggregates is determined from their growth rate in dependence on the cosolvents. The effect of the cosolvent is attributed to the interaction potential on the structured layer of hydration water around the aggregates. It is surmised that the latter is perturbed by the cosolvent and thus the residual repulsive hydration force between the aggregates is reduced. The larger the molar volume of the cosolvent, the more pronounced is the effect. This framework provides a molecular-level understanding of solvent-mediated effective interactions in polymer solutions and new opportunities for the rational control of self-assembly in complex soft matter systems.}, language = {en} } @article{ZhongMetwalliRawolleetal.2016, author = {Zhong, Qi and Metwalli, Ezzeldin and Rawolle, Monika and Kaune, Gunar and Bivigou Koumba, Achille Mayelle and Laschewsky, Andre and Papadakis, Christine M. and Cubitt, Robert and Wang, Jiping and M{\"u}ller-Buschbaum, Peter}, title = {Influence of Hydrophobic Polystyrene Blocks on the Rehydration of Polystyrene-block-poly(methoxy diethylene glycol acrylate)-block-polystyrene Films Investigated by in Situ Neutron Reflectivity}, series = {Macromolecules : a publication of the American Chemical Society}, volume = {49}, journal = {Macromolecules : a publication of the American Chemical Society}, publisher = {American Chemical Society}, address = {Washington}, issn = {0024-9297}, doi = {10.1021/acs.macromol.5b02279}, pages = {317 -- 326}, year = {2016}, abstract = {The rehydration of thermoresponsive polystyrene-block-poly(methoxy diethylene glycol acrylate)-block-polystyrene (PS-b-PMDEGA-b-PS) films forming a lamellar microphase-separated structure is investigated by in situ neutron reflectivity in a D2O vapor atmosphere. The rehydration of collapsed PS-b-PMDEGA-b-PS films is realized by a temperature change from 45 to 23 degrees C and comprises (1) condensation and absorption of D2O, (2) evaporation of D2O, and (3) reswelling of the film due to internal rearrangement. The hydrophobic PS layers hinder the absorption of condensed D2O, and a redistribution of embedded D2O between the hydrophobic PS layers and the hydrophilic PMDEGA layers is observed. In contrast, the rehydration of semiswollen PS-b-PMDEGA-b-PS films (temperature change from 35 to 23 degrees C) shows two prominent differences: A thicker D2O layer condenses on the surface, causing a more enhanced evaporation of D2O. The rehydrated films differ in film thickness and volume fraction of D2O, which is due to the different thermal protocols, although the final temperature is identical.}, language = {en} } @article{KleinpeterKoch2016, author = {Kleinpeter, Erich and Koch, Andreas}, title = {Y-aromaticity - existing: yes or no? An answer given on the magnetic criterion (TSNMRS)}, series = {Tetrahedron}, volume = {72}, journal = {Tetrahedron}, publisher = {Elsevier}, address = {Oxford}, issn = {0040-4020}, doi = {10.1016/j.tet.2016.02.020}, pages = {1675 -- 1685}, year = {2016}, abstract = {The spatial magnetic properties (Through Space NMR Shieldings - TSNMRS) of a number of Y-shaped structures possessing 4n+2 pi-electrons (i.a. the trimethylenemethane ions TMM2+, TMM2-, the guanidinium cation, substituted and hetero analogues) have been computed, visualized as Isochemical Shielding Surfaces (ICSS) of various size and direction, were examined subject to present Y-aromaticity and the results compared with energetic and geometric criteria obtained already. (C) 2016 Elsevier Ltd. All rights reserved.}, language = {en} } @article{AndrewsRossMunzkeetal.2016, author = {Andrews, Nicholas L. P. and Ross, Rachel and Munzke, Dorit and van Hoorn, Camiel and Brzezinski, Andrew and Barnes, Jack A. and Reich, Oliver and Loock, Hans-Peter}, title = {In-fiber Mach-Zehnder interferometer for gas refractive index measurements based on a hollow-core photonic crystal fiber}, series = {Optics express : the international electronic journal of optics}, volume = {24}, journal = {Optics express : the international electronic journal of optics}, publisher = {Optical Society of America}, address = {Washington}, issn = {1094-4087}, doi = {10.1364/OE.24.014086}, pages = {14086 -- 14099}, year = {2016}, abstract = {We describe an in-fiber interferometer based on a gas-filled hollow-core photonic crystal fiber. Expressions for the sensitivity, figure of merit and refractive index resolution are derived, and values are experimentally measured and theoretically validated using mode field calculations. The refractive indices of nine monoatomic and molecular gases are measured with a resolution of delta(ns) < 10(-6). (C)2016 Optical Society of America}, language = {en} } @article{OmorogieBabalolaUnuabonahetal.2016, author = {Omorogie, Martins O. and Babalola, Jonathan Oyebamiji and Unuabonah, Emmanuel Iyayi and Gong, Jian R.}, title = {Clean technology approach for the competitive binding of toxic metal ions onto MnO2 nano-bioextractant}, series = {Clean technologies and environmental policy}, volume = {18}, journal = {Clean technologies and environmental policy}, publisher = {Springer}, address = {New York}, issn = {1618-954X}, doi = {10.1007/s10098-015-1004-z}, pages = {171 -- 184}, year = {2016}, abstract = {The competitive extraction of Cr(III) onto Nauclea diderrichii seed epicarp doped with MnO2 nanoparticles (MnO2 nano-bioextractant (MNB)) in a single and binary batch system was studied. For validity of experimental data, chi square test, root mean square error, sum of the square errors, hybrid fractional error function, Marquart's percent standard deviation and standard absolute error were used. Among the kinetic models used, pseudo-second-order and Langmuir equations gave the best fits for the experimental data, with qe (mg g) for the uptake of Cr(III) in single metal system onto MNB, then Cr(III) with Cd(II), Pb(II), Hg(II), KCl and CaCl2 in binary metal systems onto MNB were 2.611, then 1.989, 1.016, 2.208, 1.249 and 1.868 from kinetic standpoint, respectively. The initial sorption rates, h (mg/g/min), and half lives, t1/2 (min), for the uptake of Cr(III) in single metal system onto MNB, then Cr(III) with Cd(II), Pb(II), Hg(II), KCl and CaCl2 in binary metal system onto MNB were 3.497, then 2.311, 2.274, 0.242, 2.956, 45.568 and 0.747, then 5.769, 1.766, 12.144, 1.762, and 2.415, respectively. Physicochemical surface analyses such as pH of point of zero charge, Brunauer-Emmett-Teller single point and multi-point techniques for surface area analyses, scanning electron microscopy and transmission electron microscopy were done on MNB and MnO2 nanoparticles in order to understand their surface microstructures. Desorption study showed that MNB can be recycled and used for future study. Hence, MNB showed good potential to remediate Cr(III) from wastewaters and polluted water.}, language = {en} } @article{OmorogieBabalolaUnuabonahetal.2016, author = {Omorogie, Martins O. and Babalola, Jonathan Oyebamiji and Unuabonah, Emmanuel Iyayi and Song, Weiguo and Gong, Jian Ru}, title = {Efficient chromium abstraction from aqueous solution using a low-cost biosorbent: Nauclea diderrichii seed biomass waste}, series = {Journal of Saudi Chemical Society}, volume = {20}, journal = {Journal of Saudi Chemical Society}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1319-6103}, doi = {10.1016/j.jscs.2012.09.017}, pages = {49 -- 57}, year = {2016}, abstract = {Toxic Cr(III) which poses environmental hazard to flora and fauna was efficiently abstracted by low-cost Nauclea diderrichii seed biomass (NDS) with good sequestral capacity for this metal was investigated in this study. The NDS surface analyses showed that it has a specific surface area of 5.36 m(2)/g and pHpzc of 4.90. Thermogravimetric analysis of NDS showed three consecutive weight losses from 50-200 degrees C (ca. 5\%), 200-400 C (ca. 35\%), >400 degrees C (ca. 10\%), corresponding to external water molecules, structural water molecules and heat induced condensation reactions respectively. Differential thermogram of NDS presented a large endothermic peak between 20-510 degrees C suggesting bond breakage and dissociation with the ultimate release of small molecules. The experimental data showed kinetically fast biosorption with increased initial Cr(III) concentrations, indicating the role of external mass transfer mechanism as the rate controlling mechanism in this adsorption process. The Langmuir biosorption capacity of NDS was 483.81 mg/g. The use of the corrected Akaike Information Criterion tool for ranking equilibrium models suggested that the Freundlich model best described the experimental data, which is an indication of the heterogeneous nature of the active sites on the surface of NDS. N. diderrichii seed biomass is an easily sourced, cheap and environmental friendly biosorbent which will serve as a good and cost effective alternative to activated carbon for the treatment of polluted water and industrial effluents. (C) 2012 King Saud University. Production and hosting by Elsevier B.V. All rights reserved.}, language = {en} } @article{SoliveresManningPratietal.2016, author = {Soliveres, Santiago and Manning, Peter and Prati, Daniel and Gossner, Martin M. and Alt, Fabian and Arndt, Hartmut and Baumgartner, Vanessa and Binkenstein, Julia and Birkhofer, Klaus and Blaser, Stefan and Bluethgen, Nico and Boch, Steffen and Boehm, Stefan and Boerschig, Carmen and Buscot, Francois and Diekoetter, Tim and Heinze, Johannes and Hoelzel, Norbert and Jung, Kirsten and Klaus, Valentin H. and Klein, Alexandra-Maria and Kleinebecker, Till and Klemmer, Sandra and Krauss, Jochen and Lange, Markus and Morris, E. Kathryn and Mueller, Joerg and Oelmann, Yvonne and Overmann, J{\"o}rg and Pasalic, Esther and Renner, Swen C. and Rillig, Matthias C. and Schaefer, H. Martin and Schloter, Michael and Schmitt, Barbara and Schoening, Ingo and Schrumpf, Marion and Sikorski, Johannes and Socher, Stephanie A. and Solly, Emily F. and Sonnemann, Ilja and Sorkau, Elisabeth and Steckel, Juliane and Steffan-Dewenter, Ingolf and Stempfhuber, Barbara and Tschapka, Marco and Tuerke, Manfred and Venter, Paul and Weiner, Christiane N. and Weisser, Wolfgang W. and Werner, Michael and Westphal, Catrin and Wilcke, Wolfgang and Wolters, Volkmar and Wubet, Tesfaye and Wurst, Susanne and Fischer, Markus and Allan, Eric}, title = {Locally rare species influence grassland ecosystem multifunctionality}, series = {Philosophical transactions of the Royal Society of London : B, Biological sciences}, volume = {371}, journal = {Philosophical transactions of the Royal Society of London : B, Biological sciences}, publisher = {Royal Society}, address = {London}, issn = {0962-8436}, doi = {10.1098/rstb.2015.0269}, pages = {3175 -- 3185}, year = {2016}, abstract = {Species diversity promotes the delivery of multiple ecosystem functions (multifunctionality). However, the relative functional importance of rare and common species in driving the biodiversity multifunctionality relationship remains unknown. We studied the relationship between the diversity of rare and common species (according to their local abundances and across nine different trophic groups), and multifunctionality indices derived from 14 ecosystem functions on 150 grasslands across a land use intensity (LUI) gradient. The diversity of above- and below-ground rare species had opposite effects, with rare above-ground species being associated with high levels of multifunctionality, probably because their effects on different functions did not trade off against each other. Conversely, common species were only related to average, not high, levels of multifunctionality, and their functional effects declined with LUI. Apart from the community level effects of diversity, we found significant positive associations between the abundance of individual species and multifunctionality in 6\% of the species tested. Species specific functional effects were best predicted by their response to LUI: species that declined in abundance with land use intensification were those associated with higher levels of multifunctionality. Our results highlight the importance of rare species for ecosystem multifunctionality and help guiding future conservation priorities.}, language = {en} }