@article{vonRuestenLangeLuetzowNeffeetal.2012, author = {von R{\"u}sten-Lange, Maik and Luetzow, Karola and Neffe, Axel T. and Lendlein, Andreas}, title = {Characterization of oligo(ethylene glycol) and oligoglycerol functionalized poly(ether imide) by angle-dependent X-ray photoelectron spectroscopy}, series = {Journal of applied biomaterials \& functional materials}, volume = {10}, journal = {Journal of applied biomaterials \& functional materials}, number = {3}, publisher = {Wichtig}, address = {Milano}, issn = {2280-8000}, doi = {10.5301/JABFM.2012.10345}, pages = {215 -- 222}, year = {2012}, abstract = {Purpose: Previous investigations have shown that poly(ether imide) (PEI) membranes can be functionalized with aminated macromolecules. In this study we explored whether the characterization of PEI functionalized with oligo(ethylene glycol) (OEG) or linear, side chain methylated oligoglycerols (OGMe), by angle-dependent X-ray induced photoelectron spectroscopy (XPS) can be used to prove the functionalization, give insight into the reaction mechanism and reveal the spatial distribution of the grafts. Methods: PEI membranes were functionalized under alkaline conditions using an aqueous solution with 2 wt\% of alpha-amino-methoxy oligo(ethylene glycol) (M-n = 1,320 g.mol(-1)) or linear, side chain methylated monoamine oligoglycerols (M-n = 1,120, 1,800 or 2,270 g.mol(-1)), respectively. The functionalized membranes were investigated using XPS measurements at different detector angles to enable comparison between the signals related to the bulk and surface volume and were compared with untreated and alkaline-treated PEI membranes. Results: While at a perpendicular detector angle the bulk signals of the PEI were prominent, at larger surface volume-related detector angles, the signals for OGMe and OEG were determinable. Conclusion: The surface functionalization of PEI with OEG and OGMe could be verified by the angle-dependent XPS. The observations proved the functionalization at the PEI surface, as the polyethers were detected at angles providing signals of the surface volume. Furthermore, the chemical functions determined verified a covalent binding via the nucleophilic addition of the amine functionalized OGMe and OEG to the PEI imide function.}, language = {en} } @article{vonMoritz2012, author = {von Moritz, Brescius}, title = {Connecting the new world}, volume = {XIII}, number = {25}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1617-5239}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-62386}, pages = {11 -- 33}, year = {2012}, abstract = {This article explores the link between the profound technological transformations of the nineteenth century and the life and work of the Prussian scholar Alexander von Humboldt (1769-1859). It analyses how Humboldt sought to appropriate the revolutionary new communication and transportation technologies of the time in order to integrate the American continent into global networks of commercial, intellectual and material exchange. Recent scholarship on Humboldt's expedition to the New World (1799-1804) has claimed that his descriptions of tropical landscapes opened up South America to a range of 'transformative interventions' (Pratt) by European capitalists and investors. These studies, however, have not analysed the motivations underlying Humboldt's support for such intrusions into nature. Furthermore, they have not explored the role that such projects played in shaping Humboldt's understanding of the forces behind the progress of societies. To comprehend Humboldt's approval for human interventions in America's natural world, this study first explores the role that eighteenth-century theories of progress and the notion of geographical determinism played in shaping his conception of civilisational development. It will look at concrete examples of transformative interventions in the American hemisphere that were actively proposed by Humboldt and intended to overcome natural obstacles to human interaction. These were the use of steamships, electric telegraphy, railroads and large-scale canals that together enabled global trade and communication to occur at an unprecedented pace. All these contemporary innovations will be linked to the four motifs of nets, mobility, progress and acceleration, which were driving forces behind the 'transformation of the world' that took place in the course of the nineteenth century.}, language = {en} } @article{VoelzkeStutzigThorhaueretal.2012, author = {Voelzke, Mathias and Stutzig, Norman and Thorhauer, Hans-Alexander and Granacher, Urs}, title = {Promoting lower extremity strength in elite volleyball players: Effects of two combined training methods}, series = {JOURNAL OF SCIENCE AND MEDICINE IN SPORT}, volume = {15}, journal = {JOURNAL OF SCIENCE AND MEDICINE IN SPORT}, number = {5}, publisher = {ELSEVIER SCI LTD}, address = {OXFORD}, issn = {1440-2440}, doi = {10.1016/j.jsams.2012.02.004}, pages = {457 -- 462}, year = {2012}, abstract = {Objectives: To compare the impact of short term training with resistance plus plyometric training (RT+P) or electromyostimulation plus plyometric training (EMS+P) on explosive force production in elite volleyball players. Design: Sixteen elite volleyball players of the first German division participated in a training study. Methods: The participants were randomly assigned to either the RT+P training group (n = 8) or the EMS+P training group (n= 8). Both groups participated in a 5-week lower extremity exercise program. Pre and post tests included squat jumps (Si), countermovement jumps (CMJ), and drop jumps (DJ) on a force plate. The three-step reach height (RH) was assessed using a custom-made vertec apparatus. Fifteen m straight and lateral sprint (S15s and S15l) were assessed using photoelectric cells with interims at 5 m and 10 m. Results: RT+P training resulted in significant improvements in Si (+2.3\%) and RH (+0.4\%) performance. The EMS+P training group showed significant increases in performance of CMJ (+3.8\%), DJ (+6.4\%), RH (+1.6\%), S15l (-3.8\%) and after 5 m and 10 m of the S15s (-2.6\%; -0.5\%). The comparison of training-induced changes between the two intervention groups revealed significant differences for the Si (p = 0.023) in favor of RT+P and for the S15s after 5 m (p = 0.006) in favor of EMS+P. Conclusions: The results indicate that RT+P training is effective in promoting jump performances and EMS+P training increases jump, speed and agility performances of elite volleyball players. (c) 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.}, language = {en} } @article{VinnikSilveiraKiselevetal.2012, author = {Vinnik, Lev and Silveira, Graca and Kiselev, Sergei and Farra, Veronique and Weber, Michael H. and Stutzmann, Eleonore}, title = {Cape verde hotspot from the upper crust to the top of the lower mantle}, series = {Earth \& planetary science letters}, volume = {319}, journal = {Earth \& planetary science letters}, number = {4}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2011.12.017}, pages = {259 -- 268}, year = {2012}, abstract = {We investigate the crust, upper mantle and mantle transition zone of the Cape Verde hotspot by using seismic P and S receiver functions from several tens of local seismograph stations. We find a strong discontinuity at a depth of similar to 10 km underlain by a similar to 15-km thick layer with a high (similar to 1.9) Vp/Vs velocity ratio. We interpret this discontinuity and the underlying layer as the fossil Moho, inherited from the pre-hotspot era, and the plume-related magmatic underplate. Our uppermost-mantle models are very different from those previously obtained for this region: our S velocity is much lower and there are no indications of low densities. Contrary to previously published arguments for the standard transition zone thickness our data indicate that this thickness under the Cape Verde islands is up to similar to 30 km less than in the ambient mantle. This reduction is a combined effect of a depression of the 410-km discontinuity and an uplift of the 660-km discontinuity. The uplift is in contrast to laboratory data and some seismic data on a negligible dependence of depth of the 660-km discontinuity on temperature in hotspots. A large negative pressure-temperature slope which is suggested by our data implies that the 660-km discontinuity may resist passage of the plume. Our data reveal beneath the islands a reduction of S velocity of a few percent between 470-km and 510-km depths. The low velocity layer in the upper transition zone under the Cape Verde archipelago is very similar to that previously found under the Azores and a few other hotspots. In the literature there are reports on a regional 520-km discontinuity, the impedance of which is too large to be explained by the known phase transitions. Our observations suggest that the 520-km discontinuity may present the base of the low-velocity layer in the transition zone.}, language = {en} } @article{VinnikKiselevWeberetal.2012, author = {Vinnik, L. and Kiselev, S. and Weber, Michael H. and Oreshin, S. and Makeyeva, L.}, title = {Frozen and active seismic anisotropy beneath southern Africa}, series = {Geophysical research letters}, volume = {39}, journal = {Geophysical research letters}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0094-8276}, doi = {10.1029/2012GL051326}, pages = {6}, year = {2012}, abstract = {P receiver functions from 23 stations of the SASE experiment in southern Africa are inverted simultaneously with SKS waveforms for azimuthal anisotropy in the upper mantle. Our analysis resolves the long-standing issue of depth dependence and origins of anisotropy beneath southern Africa. In the uppermost mantle we observe anisotropy with a nearly E-W fast direction, parallel to the trend of the Limpopo belt. This anisotropy may be frozen since the Archean. At a depth of 160 km the fast direction of anisotropy changes to 40 degrees and becomes close to the recent plate motion direction. This transition is nearly coincident in depth with activation of dominant glide systems in olivine and with a pronounced change in other properties of the upper mantle. Another large change in the fast direction of anisotropy corresponds to the previously found low-S-velocity layer atop the 410-km discontinuity. Citation: Vinnik, L., S. Kiselev, M. Weber, S. Oreshin, and L. Makeyeva (2012), Frozen and active seismic anisotropy beneath southern Africa, Geophys. Res. Lett., 39, L08301, doi: 10.1029/2012GL051326.}, language = {en} } @article{VignonZellwegerRahnenfuehrerTheuringetal.2012, author = {Vignon-Zellweger, Nicolas and Rahnenf{\"u}hrer, Jan and Theuring, Franz and Hocher, Berthold}, title = {Analysis of cardiac and renal endothelin receptors by in situ hybridization in mice}, series = {Clinical laboratory : the peer reviewed journal for clinical laboratories and laboratories related to blood transfusion}, volume = {58}, journal = {Clinical laboratory : the peer reviewed journal for clinical laboratories and laboratories related to blood transfusion}, number = {9-10}, publisher = {Clin Lab Publ., Verl. Klinisches Labor}, address = {Heidelberg}, issn = {1433-6510}, doi = {10.7754/Clin.Lab.2012.120216}, pages = {939 -- 949}, year = {2012}, abstract = {Background: Endothelin-1 (ET-1) is a multifunctional peptide, which is implicated in the renal and cardiac physicology as well as in many pathologies of these systems. ET-1's actions take place after the activation of two receptors: ETA and ETB. The expression of these receptors may be modulated during the pathologic process. The analysis of the distribution and level of expression of the receptors in animal models is therefore crucial. Methods: We developed a protocol for non-radioactive in situ hybridization for the mRNA of the two endothelin receptors on paraffin-embedded tissue using digoxigenin-labeled RNA probes. Results: In heart and kidney, the staining was reliable and specific. In a mouse model for endothelin/nitric oxide imbalance, cardiac ETB expression was reduced. The distribution of the receptors was in accordance with the actual knowledge. Differences in cell specific expression are discussed. Conclusions: We developed a protocol for the in situ hybridization of the endothelin receptors in mice. Given that the endothelin system is implicated in the development of many diseases, we believe that this protocol may be useful for a number of future preclinical studies.}, language = {en} } @article{VickersCheethamBirminghametal.2012, author = {Vickers, Steven P. and Cheetham, Sharon C. and Birmingham, Gareth D. and Rowley, Helen L. and Headland, Katie R. and Dickinson, Keith and Grempler, Rolf and Hocher, Berthold and Mark, Michael and Klein, Thomas}, title = {Effects of the DPP-4 Inhibitor, Linagliptin, in Diet-Induced obese rats a comparison in Naive and Exenatide-Treated Animals}, series = {Clinical laboratory : the peer reviewed journal for clinical laboratories and laboratories related to blood transfusion}, volume = {58}, journal = {Clinical laboratory : the peer reviewed journal for clinical laboratories and laboratories related to blood transfusion}, number = {7-8}, publisher = {Clin Lab Publ., Verl. Klinisches Labor}, address = {Heidelberg}, issn = {1433-6510}, doi = {10.7754/Clin.Lab.2011.110919}, pages = {787 -- 799}, year = {2012}, abstract = {Background: To assess the chronic effect of the DPP-4 inhibitor, linagliptin, alone, in combination with exenatide, and during exenatide withdrawal, in diet-induced obese (DIO) rats. Methods: Female Wistar rats were exposed to a cafeteria diet to induce obesity. Animals were then dosed with vehicle or linagliptin (3 mg/kg PO) orally once-daily for a 28 day period. In a subsequent study, rats received exenatide (either 3 or 30 mu g/kg/day) or vehicle by osmotic mini-pump for 28 days. In addition, groups of animals were dosed orally with linagliptin either alone or in combination with a 3 mu g/kg/day exenatide dose for the study duration. In a final study, rats were administered exenatide (30 mu g/kg/day) or vehicle by osmotic mini-pump for eleven days. Subsequently, exenatide-treated animals were transferred to vehicle or continued exenatide infusion for a further ten days. Animals transferred from exenatide to vehicle were also dosed orally with either vehicle or linagliptin. In all studies, body weight, food and water intake were recorded daily and relevant plasma parameters and carcass composition were determined. Results: In contrast to exenatide, linagliptin did not significantly reduce body weight or carcass fat in DIO rats versus controls. Linagliptin augmented the effect of exenatide to reduce body fat when given in combination but did not affect the body weight response. In rats withdrawn from exenatide, weight regain was observed such that body weight was not significantly different to controls. Linagliptin reduced weight regain after withdrawal of exenatide such that a significant difference from controls was evident. Conclusions: These data demonstrate that linagliptin does not significantly alter body weight in either untreated or exenatide-treated DIO rats, although it delays weight gain after exenatide withdrawal. This finding may suggest the utility of DPP-4 inhibitors in reducing body weight during periods of weight gain.}, language = {en} } @article{VerheyenBaetenDeFrenneetal.2012, author = {Verheyen, Kris and Baeten, Lander and De Frenne, Pieter and Bernhardt-R{\"o}mermann, Markus and Brunet, Jorg and Cornelis, Johnny and Decocq, Guillaume and Dierschke, Hartmut and Eriksson, Ove and Hedl, Radim and Heinken, Thilo and Hermy, Martin and Hommel, Patrick and Kirby, Keith J. and Naaf, Tobias and Peterken, George and Petrik, Petr and Pfadenhauer, Joerg and Van Calster, Hans and Walther, Gian-Reto and Wulf, Monika and Verstraeten, Gorik}, title = {Driving factors behind the eutrophication signal in understorey plant communities of deciduous temperate forests}, series = {The journal of ecology}, volume = {100}, journal = {The journal of ecology}, number = {2}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0022-0477}, doi = {10.1111/j.1365-2745.2011.01928.x}, pages = {352 -- 365}, year = {2012}, abstract = {1. Atmospheric nitrogen (N) deposition is expected to change forest understorey plant community composition and diversity, but results of experimental addition studies and observational studies are not yet conclusive. A shortcoming of observational studies, which are generally based on resurveys or sampling along large deposition gradients, is the occurrence of temporal or spatial confounding factors. 2. We were able to assess the contribution of N deposition versus other ecological drivers on forest understorey plant communities by combining a temporal and spatial approach. Data from 1205 (semi-)permanent vegetation plots taken from 23 rigorously selected understorey resurvey studies along a large deposition gradient across deciduous temperate forest in Europe were compiled and related to various local and regional driving factors, including the rate of atmospheric N deposition, the change in large herbivore densities and the change in canopy cover and composition. 3. Although no directional change in species richness occurred, there was considerable floristic turnover in the understorey plant community and a shift in species composition towards more shade-tolerant and nutrient-demanding species. However, atmospheric N deposition was not important in explaining the observed eutrophication signal. This signal seemed mainly related to a shift towards a denser canopy cover and a changed canopy species composition with a higher share of species with more easily decomposed litter. 4. Synthesis. Our multi-site approach clearly demonstrates that one should be cautious when drawing conclusions about the impact of atmospheric N deposition based on the interpretation of plant community shifts in single sites or regions due to other, concurrent, ecological changes. Even though the effects of chronically increased N deposition on the forest plant communities are apparently obscured by the effects of canopy changes, the accumulated N might still have a significant impact. However, more research is needed to assess whether this N time bomb will indeed explode when canopies will open up again.}, language = {en} } @article{VerganiCarminatiFerrarietal.2012, author = {Vergani, Marco and Carminati, Marco and Ferrari, Giorgio and Landini, Ettore and Caviglia, Claudia and Heiskanen, Arto and Comminges, Clement and Zor, Kinga and Sabourin, David and Dufva, Martin and Dimaki, Maria and Raiteri, Roberto and Wollenberger, Ursula and Emneus, Jenny and Sampietro, Marco}, title = {Multichannel bipotentiostat integrated with a microfluidic platform for electrochemical real-time monitoring of cell cultures}, series = {IEEE Transactions on biomedical circuits and systems}, volume = {6}, journal = {IEEE Transactions on biomedical circuits and systems}, number = {5}, publisher = {Inst. of Electr. and Electronics Engineers}, address = {Piscataway}, issn = {1932-4545}, doi = {10.1109/TBCAS.2012.2187783}, pages = {498 -- 507}, year = {2012}, abstract = {An electrochemical detection system specifically designed for multi-parameter real-time monitoring of stem cell culturing/differentiation in a microfluidic system is presented. It is composed of a very compact 24-channel electronic board, compatible with arrays of microelectrodes and coupled to a microfluidic cell culture system. A versatile data acquisition software enables performing amperometry, cyclic voltammetry and impedance spectroscopy in each of the 12 independent chambers over a 100 kHz bandwidth with current resolution down to 5 pA for 100 ms measuring time. The design of the platform, its realization and experimental characterization are reported, with emphasis on the analysis of impact of input capacitance (i.e., microelectrode size) and microfluidic pump operation on current noise. Programmable sequences of successive injections of analytes (ferricyanide and dopamine) and rinsing buffer solution as well as the impedimetric continuous tracking for seven days of the proliferation of a colony of PC12 cells are successfully demonstrated.}, language = {en} } @article{VarshneyKumarIgnatovaetal.2012, author = {Varshney, Nishant Kumar and Kumar, R. Suresh and Ignatova, Zoya and Prabhune, Asmita and Pundle, Archana and Dodson, Eleanor and Suresh, C. G.}, title = {Crystallization and X-ray structure analysis of a thermostable penicillin G acylase from Alcaligenes faecalis}, series = {Acta crystallographica : Section F, Structural biology communications}, volume = {68}, journal = {Acta crystallographica : Section F, Structural biology communications}, number = {3}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {1744-3091}, doi = {10.1107/S1744309111053930}, pages = {273 -- 277}, year = {2012}, abstract = {The enzyme penicillin G acylase (EC 3.5.1.11) catalyzes amide-bond cleavage in benzylpenicillin (penicillin G) to yield 6-aminopenicillanic acid, an intermediate chemical used in the production of semisynthetic penicillins. A thermostable penicillin G acylase from Alcaligenes faecalis (AfPGA) has been crystallized using the hanging-drop vapour-diffusion method in two different space groups: C2221, with unit-cell parameters a = 72.9, b = 86.0, c = 260.2 angstrom, and P41212, with unit-cell parameters a = b = 85.6, c = 298.8 angstrom. Data were collected at 293 K and the structure was determined using the molecular-replacement method. Like other penicillin acylases, AfPGA belongs to the N-terminal nucleophilic hydrolase superfamily, has undergone post-translational processing and has a serine as the N-terminal residue of the beta-chain. A disulfide bridge has been identified in the structure that was not found in the other two known penicillin G acylase structures. The presence of the disulfide bridge is perceived to be one factor that confers higher stability to this enzyme.}, language = {en} } @article{VanderMeerenMischkeSunjidmaaetal.2012, author = {Van der Meeren, T. and Mischke, Steffen and Sunjidmaa, N. and Herzschuh, Ulrike and Ito, E. and Martens, K. and Verschuren, Dirk}, title = {Subfossil ostracode assemblages from Mongolia quantifying response for paleolimnological applications}, series = {Ecological indicators : integrating monitoring, assessment and management}, volume = {14}, journal = {Ecological indicators : integrating monitoring, assessment and management}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1470-160X}, doi = {10.1016/j.ecolind.2011.07.004}, pages = {138 -- 151}, year = {2012}, abstract = {Ostracodes (Ostracoda, Crustacea) are aquatic micro-crustaceans with a significant representation in the fossil record. If the environmental influence on the species composition of their communities is robustly quantified, past changes in ostracode communities reflected in fossil assemblages can be used for paleo-environmental reconstruction. We analyzed ostracode assemblages in recently deposited surface sediments from 56 lakes in western and central Mongolia, and simultaneously recorded local water chemistry and solute concentration in order to elucidate the distribution of individual ostracode species in relation to these broad environmental gradients. Multivariate analysis indicated that the species variation in ostracode assemblages could be mainly attributed to variations in percent calcium (\%Ca) relative to total cation content, mean annual precipitation, calcium concentration, alkalinity, percent bicarbonate relative to total anion content, and mean July temperature. This matches well with the results of a similar analysis on presence/absence data of living ostracodes in nearshore samples, even though some differences exist between the faunal composition of both datasets. The documented response of ostracode species to environmental variation tracks the typical solute evolutionary pathway for surface waters in this region, characterized by calcite precipitation and consequent depletion in dissolved calcium. Hence, the best quantitative inference model (WA-PLS model with R-jack(2) = 0.70, RMSEP = 0.40) for paleolimnological application was obtained for \%Ca. Comparison between this model and a specific conductance (SC) inference model based on the same dataset, and based on ostracode datasets from different regions, indicated that the \%Ca inference model suffers less than the SC inference model from a step-change in reconstructed values. The statistical power of different inference models based on Mongolian ostracodes are variously affected by the common dominance of a single euryhaline species (Limnocythere inopinata), limited faunal turnover in the freshwater portion of the salinity gradient, and the bimodal frequency distribution of SC among regional lakes. The latter probably represents true scarcity of lakes with intermediate salinity rather than a biased representation in our dataset. In a broader context of ostracode ecology, and with respect to regional paleolimnological applications, we highlight the potential of fossil Mongolian ostracode assemblages to trace past hydrological shifts associated with changes in groundwater inflow.}, language = {en} } @article{vandenBeemtCinkayaErdemetal.2012, author = {van den Beemt, Martijn and {\c{C}}inkaya, Muhammed and Erdem, Didem Tuğ{\c{c}}e and Janssen, Robert}, title = {Conclusion for future teaching}, series = {Potsdamer geographische Praxis}, journal = {Potsdamer geographische Praxis}, number = {1}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {2194-1599}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-65880}, pages = {99 -- 104}, year = {2012}, abstract = {1. The importance of the maps in the Atlas of European Values 2. Team teaching 3. The importance of discussions in secondary schools 4. Assignments 5. Impact 6. Comments}, language = {en} } @article{ValoriGreenDemoulinetal.2012, author = {Valori, Gherardo and Green, Lucie M. and Demoulin, Pascal and Vargas Dominguez, S. and van Driel-Gesztelyi, L. and Wallace, A. and Baker, Daniel N. and Fuhrmann, Marcel}, title = {Nonlinear force-free extrapolation of emerging flux with a global twist and serpentine fine structures}, series = {Solar physics : a journal for solar and solar-stellar research and the study of solar terrestrial physics}, volume = {278}, journal = {Solar physics : a journal for solar and solar-stellar research and the study of solar terrestrial physics}, number = {1}, publisher = {Springer}, address = {Dordrecht}, issn = {0038-0938}, doi = {10.1007/s11207-011-9865-8}, pages = {73 -- 97}, year = {2012}, abstract = {We study the flux emergence process in NOAA active region 11024, between 29 June and 7 July 2009, by means of multi-wavelength observations and nonlinear force-free extrapolation. The main aim is to extend previous investigations by combining, as much as possible, high spatial resolution observations to test our present understanding of small-scale (undulatory) flux emergence, whilst putting these small-scale events in the context of the global evolution of the active region. The combination of these techniques allows us to follow the whole process, from the first appearance of the bipolar axial field on the east limb, until the buoyancy instability could set in and raise the main body of the twisted flux tube through the photosphere, forming magnetic tongues and signatures of serpentine field, until the simplification of the magnetic structure into a main bipole by the time the active region reaches the west limb. At the crucial time of the main emergence phase high spatial resolution spectropolarimetric measurements of the photospheric field are employed to reconstruct the three-dimensional structure of the nonlinear force-free coronal field, which is then used to test the current understanding of flux emergence processes. In particular, knowledge of the coronal connectivity confirms the identity of the magnetic tongues as seen in their photospheric signatures, and it exemplifies how the twisted flux, which is emerging on small scales in the form of a sea-serpent, is subsequently rearranged by reconnection into the large-scale field of the active region. In this way, the multi-wavelength observations combined with a nonlinear force-free extrapolation provide a coherent picture of the emergence process of small-scale magnetic bipoles, which subsequently reconnect to form a large-scale structure in the corona.}, language = {en} } @article{ValoriDemoulinPariat2012, author = {Valori, Gherardo and Demoulin, Pascal and Pariat, E.}, title = {Comparing values of the relative magnetic helicity in finite volumes}, series = {Solar physics : a journal for solar and solar-stellar research and the study of solar terrestrial physics}, volume = {278}, journal = {Solar physics : a journal for solar and solar-stellar research and the study of solar terrestrial physics}, number = {2}, publisher = {Springer}, address = {Dordrecht}, issn = {0038-0938}, doi = {10.1007/s11207-012-9951-6}, pages = {347 -- 366}, year = {2012}, abstract = {Relative magnetic helicity, as a conserved quantity of ideal magnetohydrodynamics, has been highlighted as an important quantity to study in plasma physics. Due to its nonlocal nature, its estimation is not straightforward in both observational and numerical data. In this study we derive expressions for the practical computation of the gauge-independent relative magnetic helicity in three-dimensional finite domains. The derived expressions are easy to implement and rapid to compute. They are derived in Cartesian coordinates, but can be easily written in other coordinate systems. We apply our method to a numerical model of a force-free equilibrium containing a flux rope, and compare the results with those obtained employing known half-space equations. We find that our method requires a much smaller volume than half-space expressions to derive the full helicity content. We also prove that values of relative magnetic helicity of different magnetic fields can be compared with each other in the same sense as free-energy values can. Therefore, relative magnetic helicity can be meaningfully and directly compared between different datasets, such as those from different active regions, but also within the same dataset at different times. Typical applications of our formulae include the helicity computation in three-dimensional models of the solar atmosphere, e.g., coronal-field reconstructions by force-free extrapolation and discretized magnetic fields of numerical simulations.}, language = {en} } @article{UusiHeikkilaBoeckenhoffWolteretal.2012, author = {Uusi-Heikkila, Silva and Boeckenhoff, Linda and Wolter, Christian and Arlinghaus, Robert}, title = {Differential Allocation by Female Zebrafish (Danio rerio) to Different-Sized Males - An Example in a Fish Species Lacking Parental Care}, series = {PLOS ONE}, volume = {7}, journal = {PLOS ONE}, number = {10}, publisher = {PUBLIC LIBRARY SCIENCE}, address = {SAN FRANCISCO}, issn = {1932-6203}, doi = {10.1371/journal.pone.0048317}, pages = {7}, year = {2012}, abstract = {Organisms allocate resources to reproduction in response to the costs and benefits of current and future reproductive opportunities. According to the differential allocation hypothesis, females allocate more resources to high-quality males. We tested whether a fish species lacking parental care (zebrafish, Danio rerio) expresses male size-dependent differential allocation in monogamous spawning trials. In addition, we tested whether reproductive allocation by females is affected by previous experience of different-quality males, potentially indicating plasticity in mate choice. To that end, females were conditioned to large, small or random-sized males (controls) for 14 days to manipulate females\’ expectations of the future mate quality. Females showed a clear preference for large males in terms of spawning probability and clutch size independent of the conditioning treatment. However, when females experienced variation in male size (random-sized conditioning treatment) they discriminated less against small males compared to females conditioned to large and small males. This might suggest that differential allocation and size-dependent sexual selection is of less relevance in nature than revealed in the present laboratory study.}, language = {en} } @article{UnuabonahElKhaiaryOluOwolabietal.2012, author = {Unuabonah, Emmanuel Iyayi and El-Khaiary, Mohammad I. and Olu-Owolabi, Bamidele I. and Adebowale, Kayode O.}, title = {Predicting the dynamics and performance of a polymer-clay based composite in a fixed bed system for the removal of lead (II) ion}, series = {Chemical engineering research and design}, volume = {90}, journal = {Chemical engineering research and design}, number = {8}, publisher = {Inst. of Electr. and Electronics Engineers}, address = {Rugby}, issn = {0263-8762}, doi = {10.1016/j.cherd.2011.11.009}, pages = {1105 -- 1115}, year = {2012}, abstract = {A polymer-clay based composite adsorbent was prepared from locally obtained kaolinite clay and polyvinyl alcohol. The composite adsorbent was used to remove lead (II) ions from aqueous solution in a fixed bed mode. The increase in bed height and initial metal ion concentration increased the adsorption capacity of lead (II) and the volume of aqueous solution treated at 50\% breakthrough. However, the adsorption capacity was reduced by almost 16.5\% with the simultaneous presence of Ca2+/Pb2+ and Na+/Pb2+ in the aqueous solution. Regeneration of the adsorbent with 0.1 M of HCl also reduced its adsorption capacity to 75.1\%. Adsorption of lead (II) ions onto the polymer-clay composite adsorbent in the presence of Na+ and Ca2+ electrolyte increased the rate of mass transfer, probably due to competition between cationic species in solution for adsorption sites. Regeneration further increased the rate of mass transfer as a result of reduced adsorption sites after the regeneration process. The length of the mass transfer zone was found to increase with increasing bed height but did not change with increasing the initial metal ion concentration. The models of Yoon-Nelson, Thomas, and Clark were found to give good fit to adsorption data. On the other hand, Bohart-Adams model was found to be a poor predictor for the column operation. The polymer-clay composite adsorbent has a good potential for the removal of lead (II) ions from highly polluted aqueous solutions.}, language = {en} } @article{UngruBlueherCoenenetal.2012, author = {Ungru, J. and Bl{\"u}her, M. and C{\"o}nen, M. and Raila, Jens and Boston, R. and Vervuert, I.}, title = {Effects of body weight reduction on blood adipokines and subcutaneous adipose tissue adipokine mRNA expression profiles in obese ponies}, series = {The veterinary record}, volume = {171}, journal = {The veterinary record}, number = {21}, publisher = {British Veterinary Association}, address = {London}, issn = {0042-4900}, doi = {10.1136/vr.100911}, pages = {528 -- +}, year = {2012}, abstract = {Fifteen obese ponies were used in a body weight (BW) reduction programme (BWRP, daily energy intake: 7.0-8.4 MJ/100 kg BW). A frequently sampled intravenous glucose tolerance test was used to assess insulin sensitivity. Subcutaneous adipose tissue biopsies of the tail head were obtained for mRNA gene expression profiles of adiponectin, retinol-binding protein 4 (RBP4), interleukin 6 (IL-6) and macrophage activation marker (CD68) before and after BWRP. Blood samples were analysed for serum leptin, serum RBP4 and plasma adiponectin. Significant BW losses occurred with 7 MJ DE/100 kg BW. Serum leptin and RBP4 were initially similar between insulin-resistant (IR) and insulin-sensitive (IS) ponies, and both significantly decreased during BWRP. Compared with IS ponies, IR ponies initially had significantly lower plasma adiponectin levels. At the beginning of BWRP, mRNA expression of RBP4, adiponectin, IL-6 and CD68 was similar between IR and IS ponies. Plasma adiponectin was strongly related to IR, whereas serum leptin and RBP4 were closely linked to adiposity, independent of insulin sensitivity. Adipose tissue mRNA expression profiles did not clearly reflect these differences. However, the role of subcutaneous adipose tissue in IR remains open.}, language = {en} } @article{UllnerAresMorellietal.2012, author = {Ullner, E. and Ares, S. and Morelli, L. G. and Oates, A. C. and J{\"u}licher, F. and Nicola, E. and Heussen, R. and Whitmore, D. and Blyuss, K. and Fryett, M. and Zakharova, A. and Koseska, A. and Nene, N. R. and Zaikin, Alexei}, title = {Noise and oscillations in biological sysems multidisciplinary approach between experimental biology, theoretical modelling and synthetic biology}, series = {International journal of modern physics : B, Condensed matter physics, statistical physics, applied physics}, volume = {26}, journal = {International journal of modern physics : B, Condensed matter physics, statistical physics, applied physics}, number = {25}, publisher = {World Scientific}, address = {Singapore}, issn = {0217-9792}, doi = {10.1142/S0217979212460095}, pages = {12}, year = {2012}, abstract = {Rapid progress of experimental biology has provided a huge flow of quantitative data, which can be analyzed and understood only through the application of advanced techniques recently developed in theoretical sciences. On the other hand, synthetic biology enabled us to engineer biological models with reduced complexity. In this review we discuss that a multidisciplinary approach between this sciences can lead to deeper understanding of the underlying mechanisms behind complex processes in biology. Following the mini symposia "Noise and oscillations in biological systems" on Physcon 2011 we have collected different research examples from theoretical modeling, experimental and synthetic biology.}, language = {en} } @article{UhligMadaboosiSchmidtetal.2012, author = {Uhlig, Katja and Madaboosi, Narayanan and Schmidt, Stephan and J{\"a}ger, Magnus S. and Rose, J{\"u}rgen and Duschl, Claus and Volodkin, Dmitry V.}, title = {3d localization and diffusion of proteins in polyelectrolyte multilayers}, series = {Soft matter}, volume = {8}, journal = {Soft matter}, number = {47}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1744-683X}, doi = {10.1039/c2sm26500a}, pages = {11786 -- 11789}, year = {2012}, abstract = {The interaction of diverse biomaterials with surfaces is more crucial than ever for biomedical applications to ensure efficiency and reproducibility. Very interesting surface materials are micrometer-thick polyelectrolyte multilayers. Not only their surface but also the bulk can be loaded with biomaterials like proteins or DNA for various purposes. Therefore, we established a method to analyze the lateral and vertical distribution of fluorescently labelled proteins of various size and charge in polyelectrolyte films composed of poly(L-lysine) and hyaluronic acid by confocal laser scanning microscopy. This approach enables us to measure the diffusion coefficients of the proteins via fluorescence recovery after photobleaching as a function of their vertical position in the film and facilitates the understanding of molecular interactions in the film with a high resolution in both space and time. As a result, we confirm that protein loading in the film is driven by electrostatic interactions - uncharged dextran molecules of 10 and 500 kDa do not diffuse into the film. Proteins of different sizes (3-11 nm) can diffuse relatively fast (D = 2-4 mm(2) s(-1)) independent of their net charge, indicating complex interpolymer interactions. This approach is a new powerful experimental tool to design the polyelectrolyte multilayers for bio-applications by finding a relationship between intermolecular interactions and mobility and availability of biomolecules to biological samples (e.g. cells) or detection units (e.g. biosensors).}, language = {en} } @article{TuerkeAndreasGossneretal.2012, author = {T{\"u}rke, Manfred and Andreas, Kerstin and Gossner, Martin M. and Kowalski, Esther and Lange, Markus and Boch, Steffen and Socher, Stephanie A. and M{\"u}ller, J{\"o}rg and Prati, Daniel and Fischer, Markus and Meyh{\"o}fer, Rainer and Weisser, Wolfgang W.}, title = {Are gastropods, rather than ants, important dispersers of seeds of myrmecochorous forest herbs?}, series = {The American naturalist : a bi-monthly journal devoted to the advancement and correlation of the biological sciences}, volume = {179}, journal = {The American naturalist : a bi-monthly journal devoted to the advancement and correlation of the biological sciences}, number = {1}, publisher = {Univ. of Chicago Press}, address = {Chicago}, issn = {0003-0147}, doi = {10.1086/663195}, pages = {124 -- 131}, year = {2012}, abstract = {Seed dispersal by ants (myrmecochory) is widespread, and seed adaptations to myrmecochory are common, especially in the form of fatty appendices (elaiosomes). In a recent study, slugs were identified as seed dispersers of myrmecochores in a central European beech forest. Here we used 105 beech forest sites to test whether myrmecochore presence and abundance is related to ant or gastropod abundance and whether experimentally exposed seeds are removed by gastropods. Myrmecochorous plant cover was positively related to gastropod abundance but was negatively related to ant abundance. Gastropods were responsible for most seed removal and elaiosome damage, whereas insects (and rodents) played minor roles. These gastropod effects on seeds were independent of region or forest management. We suggest that terrestrial gastropods can generally act as seed dispersers of myrmecochorous plants and even substitute myrmecochory, especially where ants are absent or uncommon.}, language = {en} }