@article{MeibomBarnesCoveyetal.2013, author = {Meibom, S. and Barnes, Sydney A. and Covey, K. and Jeffries, R. D. and Matt, S. and Morin, J. and Palacios, A. and Reiners, A. and Sicilia-Aguilar, A. and Irwin, J.}, title = {Angular momentum evolution of cool stars: Toward a synthesis of observations and theory before and after the ZAMS}, series = {Astronomische Nachrichten = Astronomical notes}, volume = {334}, journal = {Astronomische Nachrichten = Astronomical notes}, number = {1-2}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0004-6337}, doi = {10.1002/asna.201211777}, pages = {168 -- 171}, year = {2013}, abstract = {The coexistence of fast and slowly rotating cool stars in ZAMS clusters - forming distinct sequences in the color vs. rotation period plane - is providing clues to differences in their pre main-sequence angular momentum evolution. This Cool Stars 17 splinter was dedicated to a discussion of new observational and theoretical results that may help discriminate between proposed mechanisms for early angular momentum regulation and help us explain the observed ZAMS dichotomy.}, language = {en} } @article{RolfsDambacherCavanagh2013, author = {Rolfs, Martin and Dambacher, Michael and Cavanagh, Patrick}, title = {Visual adaptation of the perception of causality}, series = {Current biology}, volume = {23}, journal = {Current biology}, number = {3}, publisher = {Cell Press}, address = {Cambridge}, issn = {0960-9822}, doi = {10.1016/j.cub.2012.12.017}, pages = {250 -- 254}, year = {2013}, abstract = {We easily recover the causal properties of visual events, enabling us to understand and predict changes in the physical world. We see a tennis racket hitting a ball and sense that it caused the ball to fly over the net; we may also have an eerie but equally compelling experience of causality if the streetlights turn on just as we slam our car's door. Both perceptual [1] and cognitive [2] processes have been proposed to explain these spontaneous inferences, but without decisive evidence one way or the other, the question remains wide open [3-8]. Here, we address this long-standing debate using visual adaptation-a powerful tool to uncover neural populations that specialize in the analysis of specific visual features [9-12]. After prolonged viewing of causal collision events called "launches" [1], subsequently viewed events were judged more often as noncausal. These negative aftereffects of exposure to collisions are spatially localized in retinotopic coordinates, the reference frame shared by the retina and visual cortex. They are not explained by adaptation to other stimulus features and reveal visual routines in retinotopic cortex that detect and adapt to cause and effect in simple collision stimuli.}, language = {en} } @article{KleinpeterKoch2013, author = {Kleinpeter, Erich and Koch, Andreas}, title = {(Anti)aromaticity of dehydroannulenes of various ring size proved by the ring current effect in H-1 NMR spectra}, series = {Tetrahedron}, volume = {69}, journal = {Tetrahedron}, number = {5}, publisher = {Elsevier}, address = {Oxford}, issn = {0040-4020}, doi = {10.1016/j.tet.2012.12.019}, pages = {1481 -- 1488}, year = {2013}, abstract = {The spatial magnetic properties (Through-Space NMR Shieldings-TSNMRS) of already synthesized dehydro[n]annulenes of various ring size (from C-12 to C-20) have been computed, visualized as Isochemical Shielding Surfaces (ICSS) of various size and direction, and were examined subject to present (anti)aromaticity. For this purpose the thus quantified ring current effect of the macro cycles on proximate protons in proton NMR spectra was employed.}, language = {en} } @article{HoffmannJaiserHayeretal.2013, author = {Hoffmann, Sebastian T. and Jaiser, Frank and Hayer, Anna and Baessler, Heinz and Unger, Thomas and Athanasopoulos, Stavros and Neher, Dieter and Koehler, Anna}, title = {How Do Disorder, Reorganization, and Localization Influence the Hole Mobility in Conjugated Copolymers?}, series = {JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, volume = {135}, journal = {JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, number = {5}, publisher = {AMER CHEMICAL SOC}, address = {WASHINGTON}, issn = {0002-7863}, doi = {10.1021/ja308820j}, pages = {1772 -- 1782}, year = {2013}, abstract = {In order to unravel the intricate interplay between disorder effects, molecular reorganization, and charge carrier localization, a comprehensive study was conducted on hole transport in a series of conjugated alternating phenanthrene indenofluorene copolymers. Each polymer in the series contained one further comonomer comprising monoamines, diamines, or amine-free structures, whose influence on the electronic, optical, and charge transport properties was studied. The series covered a wide range of highest occupied molecular orbital (HOMO) energies as determined by cyclovoltammetry. The mobility, inferred from time-of-flight (ToF) experiments as a function of temperature and electric field, was found to depend exponentially on the HOMO energy. Since possible origins for this effect include energetic disorder, polaronic effects, and wave function localization, the relevant parameters were determined using a range of methods. Disorder and molecular reorganization were established first by an analysis of absorption and emission measurements and second by an analysis of the ToF measurements. In addition, density functional theory calculations were carried out to determine how localized or delocalized holes on a polymer chain are and to compare calculated reorganization energies with those that have been inferred from optical spectra. In summary, we conclude that molecular reorganization has little effect on the hole mobility in this system while both disorder effects and hole localization in systems with low-lying HOMOs are predominant. In particular, as the energetic disorder is comparable for the copolymers, the absolute value of the hole mobility at room temperature is determined by the hole localization associated with the triarylamine moieties.}, language = {en} } @article{BroedelRaymondDumanetal.2013, author = {Broedel, A. K. and Raymond, J. A. and Duman, J. G. and Bier, Frank Fabian and Kubick, Stefan}, title = {Functional evaluation of candidate ice structuring proteins using cell-free expression systems}, series = {JOURNAL OF BIOTECHNOLOGY}, volume = {163}, journal = {JOURNAL OF BIOTECHNOLOGY}, number = {3}, publisher = {ELSEVIER SCIENCE BV}, address = {AMSTERDAM}, issn = {0168-1656}, doi = {10.1016/j.jbiotec.2012.11.001}, pages = {301 -- 310}, year = {2013}, abstract = {Ice structuring proteins (ISPs) protect organisms from damage or death by freezing. They depress the non-equilibrium freezing point of water and prevent recrystallization, probably by binding to the surface of ice crystals. Many ISPs have been described and it is likely that many more exist in nature that have not yet been identified. ISPs come in many forms and thus cannot be reliably identified by their structure or consensus ice-binding motifs. Recombinant protein expression is the gold standard for proving the activity of a candidate ISP. Among existing expression systems, cell-free protein expression is the simplest and gives the fastest access to the protein of interest, but selection of the appropriate cell-free expression system is crucial for functionality. Here we describe cell-free expression methods for three ISPs that differ widely in structure and glycosylation status from three organisms: a fish (Macrozoarces americanus), an insect (Dendroides canadensis) and an alga (Chlamydomonas sp. CCMP681). We use both prokaryotic and eukaryotic expression systems for the production of ISPs. An ice recrystallization inhibition assay is used to test functionality. The techniques described here should improve the success of cell-free expression of ISPs in future applications. (C) 2012 Elsevier B.V. All rights reserved.}, language = {en} } @article{AliuArchambaultArlenetal.2013, author = {Aliu, E. and Archambault, S. and Arlen, T. and Aune, T. and Beilicke, M. and Benbow, W. and Bouvier, A. and Buckley, J. H. and Bugaev, V. and Cesarini, A. and Ciupik, L. and Collins-Hughes, E. and Connolly, M. P. and Cui, W. and Dickherber, R. and Duke, C. and Dumm, J. and Dwarkadas, Vikram V. and Errando, M. and Falcone, A. and Federici, S. and Feng, Q. and Finley, J. P. and Finnegan, G. and Fortson, L. and Furniss, A. and Galante, N. and Gall, D. and Gillanders, G. H. and Godambe, S. and Gotthelf, E. V. and Griffin, S. and Grube, J. and Gyuk, G. and Hanna, D. and Holder, J. and Hughes, G. and Humensky, T. B. and Kaaret, P. and Kargaltsev, O. and Karlsson, N. and Khassen, Y. and Kieda, D. and Krawczynski, H. and Krennrich, F. and Lang, M. J. and Lee, K. and Madhavan, A. S. and Maier, G. and Majumdar, P. and McArthur, S. and McCann, A. and Moriarty, P. and Mukherjee, R. and Nelson, T. and de Bhroithe, A. O\&rsquo and Faolain, and Ong, R. A. and Orr, M. and Otte, A. N. and Park, N. and Perkins, J. S. and Pohl, M. and Prokoph, H. and Quinn, J. and Ragan, K. and Reyes, L. C. and Reynolds, P. T. and Roache, E. and Roberts, M. and Saxon, D. B. and Schroedter, M. and Sembroski, G. H. and Slane, P. and Smith, A. W. and Staszak, D. and Telezhinsky, Igor O. and Tesic, G. and Theiling, M. and Thibadeau, S. and Tsurusaki, K. and Tyler, J. and Varlotta, A. and Vassiliev, V. V. and Vincent, S. and Vivier, M. and Wakely, S. P. and Weekes, T. C. and Weinstein, A. and Welsing, R. and Williams, D. A. and Zitzer, B.}, title = {DISCOVERY OF TeV GAMMA-RAY EMISSION FROM CTA 1 BY VERITAS}, series = {ASTROPHYSICAL JOURNAL}, volume = {764}, journal = {ASTROPHYSICAL JOURNAL}, number = {1}, publisher = {IOP PUBLISHING LTD}, address = {BRISTOL}, issn = {0004-637X}, doi = {10.1088/0004-637X/764/1/38}, pages = {9}, year = {2013}, abstract = {We report the discovery of TeV gamma-ray emission coincident with the shell-type radio supernova remnant (SNR) CTA 1 using the VERITAS gamma-ray observatory. The source, VER J0006+729, was detected as a 6.5 standard deviation excess over background and shows an extended morphology, approximated by a two-dimensional Gaussian of semimajor (semiminor) axis 0.degrees 30 (0.degrees 24) and a centroid 5\’ from the Fermi gamma-ray pulsar PSR J0007+7303 and its X-ray pulsar wind nebula (PWN). The photon spectrum is well described by a power-law dN/dE = N-0(E/3 TeV)(-Gamma), with a differential spectral index of Gamma = 2.2 +/- 0.2(stat) +/- 0.3(sys), and normalization N-0 = (9.1 +/- 1.3(stat) +/- 1.7(sys)) x 10(-14) cm(-2) s(-1) TeV-1. The integral flux, F-gamma = 4.0 x 10(-12) erg cm(-2) s(-1) above 1 TeV, corresponds to 0.2\% of the pulsar spin-down power at 1.4 kpc. The energetics, colocation with the SNR, and the relatively small extent of the TeV emission strongly argue for the PWN origin of the TeV photons. We consider the origin of the TeV emission in CTA 1.}, language = {en} } @article{MeliAuclercPalmqvistetal.2013, author = {Meli, Mattia and Auclerc, Apolline and Palmqvist, Annemette and Forbes, Valery E. and Grimm, Volker}, title = {Population-level consequences of spatially heterogeneous exposure to heavy metals in soil an individual-based model of springtails}, series = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, volume = {250}, journal = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-3800}, doi = {10.1016/j.ecolmodel.2012.11.010}, pages = {338 -- 351}, year = {2013}, abstract = {Contamination of soil with toxic heavy metals poses a major threat to the environment and human health. Anthropogenic sources include smelting of ores, municipal wastes, fertilizers, and pesticides. In assessing soil quality and the environmental and ecological risk of contamination with heavy metals, often homogeneous contamination of the soil is assumed. However, soils are very heterogeneous environments. Consequently, both contamination and the response of soil organisms can be assumed to be heterogeneous. This might have consequences for the exposure of soil organisms and for the extrapolation of risk from the individual to the population level. Therefore, to explore how soil contamination of different spatial heterogeneity affects population dynamics of soil invertebrates, we developed a spatially explicit individual-based model of the springtail, Folsomia candida, a standard test species for ecotoxicological risk assessment. In the model, individuals were assumed to sense and avoid contaminated habitat with a certain probability that depends on contamination level. Avoidance of contaminated areas thus influenced the individuals' movement and feeding, their exposure, and in turn all other biological processes underlying population dynamics. Model rules and parameters were based on data from the literature, or were determined via pattern-oriented modelling. The model correctly predicted several patterns that were not used for model design and calibration. Simulation results showed that the ability of the individuals to detect and avoid the toxicant, combined with the presence of clean habitat patches which act as "refuges", made equilibrium population size due to toxic effects less sensitive to increases in toxicant concentration. Additionally, the level of heterogeneity among patches of soil (i.e. the difference in concentration) was important: at the same average concentration, a homogeneously contaminated scenario was the least favourable habitat, while higher levels of heterogeneity corresponded to higher population growth rate and equilibrium size. Our model can thus be used as a tool for extrapolating from short-term effects at the individual level to long-term effects at the population level under more realistic conditions. It can thus be used to develop and extrapolate from standard ecotoxicological tests in the laboratory to ecological risk assessments.}, language = {en} } @article{BhabakKleuserHuwileretal.2013, author = {Bhabak, Krishna P. and Kleuser, Burkhard and Huwiler, Andrea and Arenz, Christoph}, title = {Effective inhibition of acid and neutral ceramidases by novel B-13 and LCL-464 analogues}, series = {Bioorganic \& medicinal chemistry : a Tetrahedron publication for the rapid dissemination of full original research papers and critical reviews on biomolecular chemistry, medicinal chemistry and related disciplines}, volume = {21}, journal = {Bioorganic \& medicinal chemistry : a Tetrahedron publication for the rapid dissemination of full original research papers and critical reviews on biomolecular chemistry, medicinal chemistry and related disciplines}, number = {4}, publisher = {Elsevier}, address = {Oxford}, issn = {0968-0896}, doi = {10.1016/j.bmc.2012.12.014}, pages = {874 -- 882}, year = {2013}, abstract = {Induction of apoptosis mediated by the inhibition of ceramidases has been shown to enhance the efficacy of conventional chemotherapy in several cancer models. Among the inhibitors of ceramidases reported in the literature, B-13 is considered as a lead compound having good in vitro potency towards acid ceramidase. Furthermore, owing to the poor activity of B-13 on lysosoamal acid ceramidase in living cells, LCL-464 a modified derivative of B-13 containing a basic omega-amino group at the fatty acid was reported to have higher potency towards lysosomal acid ceramidase in living cells. In a search for more potent inhibitors of ceramidases, we have designed a series of compounds with structural modifications of B-13 and LCL-464. In this study, we show that the efficacy of B-13 in vitro as well as in intact cells can be enhanced by suitable modification of functional groups. Furthermore, a detailed SAR investigation on LCL-464 analogues revealed novel promising inhibitors of aCDase and nCDase. In cell culture studies using the breast cancer cell line MDA-MB-231, some of the newly developed compounds elevated endogenous ceramide levels and in parallel, also induced apoptotic cell death. In summary, this study shows that structural modification of the known ceramidase inhibitors B-13 and LCL-464 generates more potent ceramidase inhibitors that are active in intact cells and not only elevates the cellular ceramide levels, but also enhances cell death.}, language = {en} } @article{PieplowHenkel2013, author = {Pieplow, Gregor and Henkel, Carsten}, title = {Fully covariant radiation force on a polarizable particle}, series = {New journal of physics : the open-access journal for physics}, volume = {15}, journal = {New journal of physics : the open-access journal for physics}, number = {4}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {1367-2630}, doi = {10.1088/1367-2630/15/2/023027}, pages = {17}, year = {2013}, abstract = {The electromagnetic force on a polarizable particle is calculated in a covariant framework. Local equilibrium temperatures for the electromagnetic field and the particle's dipole moment are assumed, using a relativistic formulation of the fluctuation-dissipation theorem. Two examples illustrate radiative friction forces: a particle moving through a homogeneous radiation background and above a planar interface. Previous results for arbitrary relative velocities are recovered in a compact way.}, language = {en} } @article{SirockoDietrichVeresetal.2013, author = {Sirocko, Frank and Dietrich, Stephan and Veres, Daniel and Grootes, Pieter M. and Schaber-Mohr, Katja and Seelos, Klemens and Nadeau, Marie-Josee and Kromer, Bernd and Rothacker, Leo and Roehner, Marieke and Krbetschek, Matthias and Appleby, Peter G. and Hambach, Ulrich and Rolf, Christian and Sudo, Masafumi and Grim, Stephanie}, title = {Multi-proxy dating of Holocene maar lakes and Pleistocene dry maar sediments in the Eifel, Germany}, series = {Quaternary science reviews : the international multidisciplinary research and review journal}, volume = {62}, journal = {Quaternary science reviews : the international multidisciplinary research and review journal}, publisher = {Elsevier}, address = {Oxford}, issn = {0277-3791}, doi = {10.1016/j.quascirev.2012.09.011}, pages = {56 -- 76}, year = {2013}, abstract = {During the last twelve years the ELSA Project (Eifel Laminated Sediment Archive) at Mainz University has drilled a total of about 52 cores from 27 maar lakes and filled-in maar basins in the Eifel/Germany. Dating has been completed for the Holocene cores using 6 different methods (Pb-210 and Cs-137 activities, palynostratigraphy, event markers, varve counting, C-14) In general, the different methods consistently complement one another within error margins. Event correlation was used for relating typical lithological changes with historically known events such as the two major Holocene flood events at 1342 AD and ca 800 BC. Dating of MIS2-MIS3 core sections is based on greyscale tuning, radiocarbon and OSL dating, magnetostratigraphy and tephrochronology. The lithological changes in the sediment cores demonstrate a sequence of events similar to the North Atlantic rapid climate variability of the Last Glacial Cycle. The warmest of the MIS3 interstadials was GI14, when a forest with abundant spruce covered the Eifel area from 55 to 48 ka BP, i.e. during a time when also other climate archives in Europe suggested very warm conditions. The forest of this "Early Stage 3 warm phase" developed subsequently into a steppe with scattered birch and pine, and finally into a glacial desert at around 25 ka BP. Evidence for Mono Lake and Laschamp geomagnetic excursions is found in two long cores. Several large eruptions during Middle and Late Pleistocene (Ulmener Maar - 11,000 varve years BP, Laacher See - 12,900 varve years BP, Mosenberg volcanoes/Meerfelder Maar 41-45 cal ka BP, Dumpel Maar 116 ka BP, Glees Maar - 151 ka BP) produced distinct ash-layers crucial for inter-core and inter-site correlations. The oldest investigated maar of the Eifel is Ar-40/Ar-39 dated to the time older than 520 ka BP.}, language = {en} } @article{GorumvanWestenKorupetal.2013, author = {Gorum, Tolga and van Westen, Cees J. and Korup, Oliver and van der Meijde, Mark and Fan, Xuanmei and van der Meer, Freek D.}, title = {Complex rupture mechanism and topography control symmetry of mass-wasting pattern, 2010 Haiti earthquake}, series = {GEOMORPHOLOGY}, volume = {184}, journal = {GEOMORPHOLOGY}, publisher = {ELSEVIER SCIENCE BV}, address = {AMSTERDAM}, issn = {0169-555X}, doi = {10.1016/j.geomorph.2012.11.027}, pages = {127 -- 138}, year = {2013}, abstract = {The 12 January 2010 M-w 7.0 Haiti earthquake occurred in a complex deformation zone at the boundary between the North American and Caribbean plates. Combined geodetic, geological and seismological data posited that surface deformation was driven by rupture on the Leogane blind thrust fault, while part of the rupture occurred as deep lateral slip on the Enriquillo-Plantain Garden Fault (EPGF). The earthquake triggered >4490 landslides, mainly shallow, disrupted rock falls, debris-soil falls and slides, and a few lateral spreads, over an area of similar to 2150 km(2). The regional distribution of these slope failures defies those of most similar earthquake-triggered landslide episodes reported previously. Most of the coseismic landslides did not proliferate in the hanging wall of the main rupture, but clustered instead at the junction of the blind Leogane and EPGF ruptures, where topographic relief and hillslope steepness are above average. Also, low-relief areas subjected to high coseismic uplift were prone to lesser hanging wall slope instability than previous studies would suggest. We argue that a combined effect of complex rupture dynamics and topography primarily control this previously rarely documented landslide pattern. Compared to recent thrust fault-earthquakes of similar magnitudes elsewhere, we conclude that lower static stress drop, mean fault displacement, and blind ruptures of the 2010 Haiti earthquake resulted in fewer, smaller, and more symmetrically distributed landslides than previous studies would suggest. Our findings caution against overly relying on across-the-board models of slope stability response to seismic ground shaking. (C) 2012 Elsevier B.V. All rights reserved.}, language = {en} } @article{MirskovaAdamovichMirskovetal.2013, author = {Mirskova, Anna N. and Adamovich, Sergey N. and Mirskov, Rudolf G. and Schilde, Uwe}, title = {Reaction of pharmacological active tris-(2-hydroxyethyl)ammonium 4-chlorophenylsulfanylacetate with ZnCl2 or NiCl2: first conversion of a protic ionic liquid into metallated ionic liquid}, series = {CHEMISTRY CENTRAL JOURNAL}, volume = {7}, journal = {CHEMISTRY CENTRAL JOURNAL}, publisher = {BIOMED CENTRAL LTD}, address = {LONDON}, issn = {1752-153X}, doi = {10.1186/1752-153X-7-34}, pages = {5}, year = {2013}, abstract = {The reaction of pharmacological active protic ionic liquid tris-(2-hydroxyethyl)ammonium 4-chlorophenylsulfanylacetate H+N(CH2CH2OH)(3) center dot (-OOCCH2SC6H4Cl-4) (1) with zinc or nickel chloride in a ratio of 2:1 affords stable at room temperature powder-like adducts [H+N(CH2CH2OH)(3)](2) center dot [M(OOCCH2SC6H4Cl-4)(2)Cl-2](2-), M = Zn (2), Ni (3). By recrystallization from aqueous alcohol compound 2 unexpectedly gives Zn(OOCCH2SC6H4Cl-4)(2) center dot 2H(2)O (4). Unlike 2, compound 3 gives crystals [N(CH2CH2OH)(3)](2)Ni2+ center dot [-OOCCH2SC6H4Cl-4](2) (5), which have a structure of metallated ionic liquid. The structure of 5 has been proved by X-ray diffraction analysis. It is the first example of the conversion of a protic ionic liquid into potentially biological active metallated ionic liquid (1 -> 3 -> 5).}, language = {en} } @article{DahlRadonBuehningetal.2013, author = {Dahl, Jan-Ulrik and Radon, Christin and B{\"u}hning, Martin and Nimtz, Manfred and Leichert, Lars I. and Denis, Yann and Jourlin-Castelli, Cecile and Iobbi-Nivol, Chantal and Mejean, Vincent and Leimk{\"u}hler, Silke}, title = {The Sulfur Carrier Protein TusA Has a Pleiotropic Role in Escherichia coli That Also Affects Molybdenum Cofactor Biosynthesis}, series = {JOURNAL OF BIOLOGICAL CHEMISTRY}, volume = {288}, journal = {JOURNAL OF BIOLOGICAL CHEMISTRY}, number = {8}, publisher = {AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC}, address = {BETHESDA}, issn = {0021-9258}, doi = {10.1074/jbc.M112.431569}, pages = {5426 -- 5442}, year = {2013}, abstract = {The Escherichia coli L-cysteine desulfurase IscS mobilizes sulfur from L-cysteine for the synthesis of several biomolecules such as iron-sulfur (FeS) clusters, molybdopterin, thiamin, lipoic acid, biotin, and the thiolation of tRNAs. The sulfur transfer from IscS to various biomolecules is mediated by different interaction partners (e.g. TusA for thiomodification of tRNAs, IscU for FeS cluster biogenesis, and ThiI for thiamine biosynthesis/tRNA thiolation), which bind at different sites of IscS. Transcriptomic and proteomic studies of a Delta tusA strain showed that the expression of genes of the moaABCDE operon coding for proteins involved in molybdenum cofactor biosynthesis is increased under aerobic and anaerobic conditions. Additionally, under anaerobic conditions the expression of genes encoding hydrogenase 3 and several molybdoenzymes such as nitrate reductase were also increased. On the contrary, the activity of all molydoenzymes analyzed was significantly reduced in the Delta tusA mutant. Characterization of the Delta tusA strain under aerobic conditions showed an overall low molybdopterin content and an accumulation of cyclic pyranopterin monophosphate. Under anaerobic conditions the activity of nitrate reductase was reduced by only 50\%, showing that TusA is not essential for molybdenum cofactor biosynthesis. We present a model in which we propose that the direction of sulfur transfer for each sulfur-containing biomolecule is regulated by the availability of the interaction partner of IscS. We propose that in the absence of TusA, more IscS is available for FeS cluster biosynthesis and that the overproduction of FeS clusters leads to a modified expression of several genes.}, language = {en} } @article{InalKoelschChiappisietal.2013, author = {Inal, Sahika and Koelsch, Jonas D. and Chiappisi, Leonardo and Kraft, Mario and Gutacker, Andrea and Janietz, Dietmar and Scherf, Ullrich and Gradzielski, Michael and Laschewsky, Andr{\´e} and Neher, Dieter}, title = {Temperature-Regulated Fluorescence Characteristics of Supramolecular Assemblies Formed By a Smart Polymer and a Conjugated Polyelectrolyte}, series = {MACROMOLECULAR CHEMISTRY AND PHYSICS}, volume = {214}, journal = {MACROMOLECULAR CHEMISTRY AND PHYSICS}, number = {4}, publisher = {WILEY-V C H VERLAG GMBH}, address = {WEINHEIM}, issn = {1022-1352}, doi = {10.1002/macp.201200493}, pages = {435 -- 445}, year = {2013}, abstract = {Aqueous mixtures of a coumarin-labeled non-ionic thermoresponsive copolymer and a cationic polythiophene exhibit marked changes in their fluorescence properties upon heating. At room temperature, emission from the label is significantly quenched due to energy transfer to the conjugated polyelectrolyte. Heating the mixture reduces the energy-transfer efficiency markedly, resulting in a clearly visible change of the emission color. Although the two macromolecules associate strongly at room temperature, the number of interacting sites is largely reduced upon the phase transition. Crucially, the intermolecular association does not suppress the responsiveness of the smart polymer, meaning that this concept should be applicable to chemo- or bioresponsive polymers with optical read-out, for example, as a sensor device.}, language = {en} } @article{WinklerKofodKrastevetal.2013, author = {Winkler, M. and Kofod, G. and Krastev, R. and Stoeckle, S. and Abel, M. W.}, title = {Exponentially Fast Thinning of Nanoscale Films by Turbulent Mixing}, series = {PHYSICAL REVIEW LETTERS}, volume = {110}, journal = {PHYSICAL REVIEW LETTERS}, number = {9}, publisher = {AMER PHYSICAL SOC}, address = {COLLEGE PK}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.110.094501}, pages = {5}, year = {2013}, abstract = {Films are nanoscopic elements of foams, emulsions, and suspensions that form a paradigm for nanochannel transport that eventually tests the limits of hydrodynamic descriptions. Here, we study the collapse of a freestanding film to its equilibrium. The generation of nanoscale films usually is a slow linear process; using thermal forcing we find unprecedented dynamics with exponentially fast thinning. The complex interplay of thermal convection, interface, and gravitational forces yields optimal turbulent mixing and transport. Domains of collapsed film are generated, elongated, and convected in a beautiful display of chaotic mixing. With a time scale analysis, we identify mixing as the dominant dynamical process responsible for exponential thinning. DOI: 10.1103/PhysRevLett.110.094501}, language = {en} } @article{SchickBojahrHerzogetal.2013, author = {Schick, Daniel and Bojahr, Andre and Herzog, Marc and Gaal, P. and Vrejoiu, I. and Bargheer, Matias}, title = {Following Strain-Induced Mosaicity Changes of Ferroelectric Thin Films by Ultrafast Reciprocal Space Mapping}, series = {Physical review letters}, volume = {110}, journal = {Physical review letters}, number = {9}, publisher = {American Physical Society}, address = {College Park}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.110.095502}, pages = {5}, year = {2013}, abstract = {We investigate coherent phonon propagation in a thin film of ferroelectric PbZr0.2Ti0.8O3 (PZT) by ultrafast x-ray diffraction experiments, which are analyzed as time-resolved reciprocal space mapping in order to observe the in-and out-of-plane structural dynamics, simultaneously. The mosaic structure of the PZT leads to a coupling of the excited out-of-plane expansion to in-plane lattice dynamics on a picosecond time scale, which is not observed for out-of-plane compression.}, language = {en} } @article{EliazarMetzler2013, author = {Eliazar, Iddo and Metzler, Ralf}, title = {Anomalous statistics of random relaxations in random environments}, series = {Physical review : E, Statistical, nonlinear and soft matter physics}, volume = {87}, journal = {Physical review : E, Statistical, nonlinear and soft matter physics}, number = {2}, publisher = {American Physical Society}, address = {College Park}, issn = {1539-3755}, doi = {10.1103/PhysRevE.87.022141}, pages = {12}, year = {2013}, abstract = {We comprehensively analyze the emergence of anomalous statistics in the context of the random relaxation ( RARE) model [Eliazar and Metzler, J. Chem. Phys. 137, 234106 ( 2012)], a recently introduced versatile model of random relaxations in random environments. The RARE model considers excitations scattered randomly across a metric space around a reaction center. The excitations react randomly with the center, the reaction rates depending on the excitations' distances from this center. Relaxation occurs upon the first reaction between an excitation and the center. Addressing both the relaxation time and the relaxation range, we explore when these random variables display anomalous statistics, namely, heavy tails at zero and at infinity that manifest, respectively, exceptionally high occurrence probabilities of very small and very large outliers. A cohesive set of closed-form analytic results is established, determining precisely when such anomalous statistics emerge.}, language = {en} } @article{FeudelSeehaferTuckermanetal.2013, author = {Feudel, Fred and Seehafer, Norbert and Tuckerman, Laurette S. and Gellert, Marcus}, title = {Multistability in rotating spherical shell convection}, series = {Physical review : E, Statistical, nonlinear and soft matter physics}, volume = {87}, journal = {Physical review : E, Statistical, nonlinear and soft matter physics}, number = {2}, publisher = {American Physical Society}, address = {College Park}, issn = {1539-3755}, doi = {10.1103/PhysRevE.87.023021}, pages = {8}, year = {2013}, abstract = {The multiplicity of stable convection patterns in a rotating spherical fluid shell heated from the inner boundary and driven by a central gravity field is presented. These solution branches that arise as rotating waves (RWs) are traced for varying Rayleigh number while their symmetry, stability, and bifurcations are studied. At increased Rayleigh numbers all the RWs undergo transitions to modulated rotating waves (MRWs) which are classified by their spatiotemporal symmetry. The generation of a third frequency for some of the MRWs is accompanied by a further loss of symmetry. Eventually a variety of MRWs, three-frequency solutions, and chaotic saddles and attractors control the dynamics for higher Rayleigh numbers.}, language = {en} } @article{LinBergerGrimmetal.2013, author = {Lin, Yue and Berger, Uta and Grimm, Volker and Huth, Franka and Weiner, Jacob}, title = {Plant interactions alter the predictions of metabolic scaling theory}, series = {PLoS one}, volume = {8}, journal = {PLoS one}, number = {2}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0057612}, pages = {6}, year = {2013}, abstract = {Metabolic scaling theory (MST) is an attempt to link physiological processes of individual organisms with macroecology. It predicts a power law relationship with an exponent of -4/3 between mean individual biomass and density during density-dependent mortality (self-thinning). Empirical tests have produced variable results, and the validity of MST is intensely debated. MST focuses on organisms' internal physiological mechanisms but we hypothesize that ecological interactions can be more important in determining plant mass-density relationships induced by density. We employ an individual-based model of plant stand development that includes three elements: a model of individual plant growth based on MST, different modes of local competition (size-symmetric vs. -asymmetric), and different resource levels. Our model is consistent with the observed variation in the slopes of self-thinning trajectories. Slopes were significantly shallower than -4/3 if competition was size-symmetric. We conclude that when the size of survivors is influenced by strong ecological interactions, these can override predictions of MST, whereas when surviving plants are less affected by interactions, individual-level metabolic processes can scale up to the population level. MST, like thermodynamics or biomechanics, sets limits within which organisms can live and function, but there may be stronger limits determined by ecological interactions. In such cases MST will not be predictive.}, language = {en} } @article{BauerSommerGaedke2013, author = {Bauer, Barbara and Sommer, Ulrich and Gaedke, Ursula}, title = {High predictability of spring phytoplankton biomass in mesocosms at the species, functional group and community level}, series = {Freshwater biology}, volume = {58}, journal = {Freshwater biology}, number = {3}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0046-5070}, doi = {10.1111/j.1365-2427.2012.02780.x}, pages = {588 -- 596}, year = {2013}, abstract = {1. Models aim to predict phytoplankton dynamics based on observed initial conditions and a set of equations and parameters. However, our knowledge about initial conditions in nature is never perfect. Thus, if phytoplankton dynamics are sensitive to small variations in initial conditions, they are difficult to predict. 2. We used time-series data from indoor mesocosm experiments with natural phyto- and zooplankton communities to quantify the extent to which small initial differences in the species, functional group and community biomass in parallel treatments were amplified or buffered over time. We compared the differences in dynamics between replicates and among all mesocosms of 1year. 3. Temperature-sensitive grazing during the exponential growth phase of phytoplankton caused divergence. In contrast, negative density dependence caused convergence. 4. Mean differences in biomass between replicates were similar for all hierarchical levels. This indicates that differences in their initial conditions were amplified to the same extent. Even though large differences in biomass occasionally occurred between replicates for a short time, dynamics returned to the same path at all hierarchical levels. This suggests that internal feedback mechanisms make the spring development of phytoplankton highly predictable.}, language = {en} }