@article{YanFangNoecheletal.2016, author = {Yan, Wan and Fang, Liang and N{\"o}chel, Ulrich and Kratz, Karl and Lendlein, Andreas}, title = {Influence of programming strain rates on the shape-memory performance of semicrystalline multiblock copolymers}, series = {Journal of polymer science : B, Polymer physics}, volume = {54}, journal = {Journal of polymer science : B, Polymer physics}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0887-6266}, doi = {10.1002/polb.24097}, pages = {1935 -- 1943}, year = {2016}, abstract = {Multiblock copolymers named PCL-PIBMD consisting of crystallizable poly(epsilon-caprolactone) segments and crystallizable poly[oligo(3S-iso-butylmorpholine-2,5-dione)] segments coupled by trimethyl hexamethylene diisocyanate provide a versatile molecular architecture for achieving shape-memory effects (SMEs) in polymers. The mechanical properties as well as the SME performance of PCL-PIBMD can be tailored by the variation of physical parameters during programming such as deformation strain or applied temperature protocols. In this study, we explored the influence of applying different strain rates during programming on the resulting nanostructure of PCL-PIBMD. Programming was conducted at 50 degrees C by elongation to epsilon(m)=50\% with strain rates of 1 or 10 or 50 mmmin(-1). The nanostructural changes were visualized by atomic force microscopy (AFM) measurements and investigated by in situ wide and small angle X-ray scattering experiments. With increasing the strain rate, a higher degree of orientation was observed in the amorphous domains. Simultaneously the strain-induced formation of new PIBMD crystals as well as the fragmentation of existing large PIBMD crystals occurred. The observed differences in shape fixity ratio and recovery stress of samples deformed with various strain rates can be attributed to their different nanostructures. The achieved findings can be relevant parameters for programming the shape-memory polymers with designed recovery forces. (c) 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1935-1943}, language = {en} } @misc{YanFriemelAloisietal.2016, author = {Yan, Robert and Friemel, Martin and Aloisi, Claudia and Huynen, Martijn and Taylor, Ian A. and Leimk{\"u}hler, Silke and Pastore, Annalisa}, title = {The eukaryotic-specific Isd11 is a complex- orphan protein with ability to bind the prokaryotic IscS}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {551}, issn = {1866-8372}, doi = {10.25932/publishup-41190}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-411906}, pages = {14}, year = {2016}, abstract = {The eukaryotic protein Isd11 is a chaperone that binds and stabilizes the central component of the essential metabolic pathway responsible for formation of iron-sulfur clusters in mitochondria, the desulfurase Nfs1. Little is known about the exact role of Isd11. Here, we show that human Isd11 (ISD11) is a helical protein which exists in solution as an equilibrium between monomer, dimeric and tetrameric species when in the absence of human Nfs1 (NFS1). We also show that, surprisingly, recombinant ISD11 expressed in E. coli co-purifies with the bacterial orthologue of NFS1, IscS. Binding is weak but specific suggesting that, despite the absence of Isd11 sequences in bacteria, there is enough conservation between the two desulfurases to retain a similar mode of interaction. This knowledge may inform us on the conservation of the mode of binding of Isd11 to the desulfurase. We used evolutionary evidence to suggest Isd11 residues involved in the interaction.}, language = {en} } @article{YanFriemelAloisietal.2016, author = {Yan, Robert and Friemel, Martin and Aloisi, Claudia and Huynen, Martijn and Taylor, Ian A. and Leimk{\"u}hler, Silke and Pastore, Annalisa}, title = {The Eukaryotic-Specific ISD11 Is a Complex-Orphan Protein with Ability to Bind the Prokaryotic IscS}, series = {PLoS one}, volume = {11}, journal = {PLoS one}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0157895}, pages = {383 -- 395}, year = {2016}, abstract = {The eukaryotic protein Isd11 is a chaperone that binds and stabilizes the central component of the essential metabolic pathway responsible for formation of iron-sulfur clusters in mitochondria, the desulfurase Nfs1. Little is known about the exact role of Isd11. Here, we show that human Isd11 (ISD11) is a helical protein which exists in solution as an equilibrium between monomer, dimeric and tetrameric species when in the absence of human Nfs1 (NFS1). We also show that, surprisingly, recombinant ISD11 expressed in E. coli co-purifies with the bacterial orthologue of NFS1, IscS. Binding is weak but specific suggesting that, despite the absence of Isd11 sequences in bacteria, there is enough conservation between the two desulfurases to retain a similar mode of interaction. This knowledge may inform us on the conservation of the mode of binding of Isd11 to the desulfurase. We used evolutionary evidence to suggest Isd11 residues involved in the interaction.}, language = {en} } @article{YanKliegl2016, author = {Yan, Ming and Kliegl, Reinhold}, title = {CarPrice versus CarpRice: Word Boundary Ambiguity Influences Saccade Target Selection During the Reading of Chinese Sentences}, series = {Journal of experimental psychology : Learning, memory, and cognition}, volume = {42}, journal = {Journal of experimental psychology : Learning, memory, and cognition}, publisher = {American Psychological Association}, address = {Washington}, issn = {0278-7393}, doi = {10.1037/xlm0000276}, pages = {1832 -- 1838}, year = {2016}, abstract = {As a contribution to a theoretical debate about the degree of high-level influences on saccade targeting during sentence reading, we investigated eye movements during the reading of structurally ambiguous Chinese character strings and examined whether parafoveal word segmentation could influence saccade-target selection. As expected, ambiguous strings took longer to process. More critically there were theoretically relevant interactions between ambiguity and launch site when first-fixation location and saccade amplitude served as dependent variables: Ambiguous strings in the parafovea triggered longer saccades and more rightward fixations for close launch sites than unambiguous ones; the reverse result was obtained for far launch sites. These crossover interactions indicate that parafoveal word segmentation influences saccade generation in Chinese and provide support of the hypothesis that high-level information can be involved in the decision about where to fixate next.}, language = {en} } @article{YadavalliLoebnerPapkeetal.2016, author = {Yadavalli, Nataraja Sekhar and Loebner, Sarah and Papke, Thomas and Sava, Elena and Hurduc, Nicolae and Santer, Svetlana}, title = {A comparative study of photoinduced deformation in azobenzene containing polymer films}, series = {Soft matter}, volume = {12}, journal = {Soft matter}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1744-683X}, doi = {10.1039/c6sm00029k}, pages = {2593 -- 2603}, year = {2016}, abstract = {In this paper two groups supporting different views on the mechanism of light induced polymer deformation argue about the respective underlying theoretical conceptions, in order to bring this interesting debate to the attention of the scientific community. The group of Prof. Nicolae Hurduc supports the model claiming that the cyclic isomerization of azobenzenes may cause an athermal transition of the glassy azobenzene containing polymer into a fluid state, the so-called photo-fluidization concept. This concept is quite convenient for an intuitive understanding of the deformation process as an anisotropic flow of the polymer material. The group of Prof. Svetlana Santer supports the re-orientational model where the mass-transport of the polymer material accomplished during polymer deformation is stated to be generated by the light-induced re-orientation of the azobenzene side chains and as a consequence of the polymer backbone that in turn results in local mechanical stress, which is enough to irreversibly deform an azobenzene containing material even in the glassy state. For the debate we chose three polymers differing in the glass transition temperature, 32 degrees C, 87 degrees C and 95 degrees C, representing extreme cases of flexible and rigid materials. Polymer film deformation occurring during irradiation with different interference patterns is recorded using a homemade set-up combining an optical part for the generation of interference patterns and an atomic force microscope for acquiring the kinetics of film deformation. We also demonstrated the unique behaviour of azobenzene containing polymeric films to switch the topography in situ and reversibly by changing the irradiation conditions. We discuss the results of reversible deformation of three polymers induced by irradiation with intensity (IIP) and polarization (PIP) interference patterns, and the light of homogeneous intensity in terms of two approaches: the re-orientational and the photo-fluidization concepts. Both agree in that the formation of opto-mechanically induced stresses is a necessary prerequisite for the process of deformation. Using this argument, the deformation process can be characterized either as a flow or mass transport.}, language = {en} } @article{XueYanChengetal.2016, author = {Xue, Zhike and Yan, Xiaoli and Cheng, Xin and Yang, Liheng and Su, Yingna and Kliem, Bernhard and Zhang, Jun and Liu, Zhong and Bi, Yi and Xiang, Yongyuan and Yang, Kai and Zhao, Li}, title = {Observing the release of twist by magnetic reconnection in a solar filament eruption}, series = {Nature Communications}, volume = {7}, journal = {Nature Communications}, publisher = {Nature Publ. Group}, address = {London}, issn = {2041-1723}, doi = {10.1038/ncomms11837}, pages = {11}, year = {2016}, abstract = {Magnetic reconnection is a fundamental process of topology change and energy release, taking place in plasmas on the Sun, in space, in astrophysical objects and in the laboratory. However, observational evidence has been relatively rare and typically only partial. Here we present evidence of fast reconnection in a solar filament eruption using high-resolution H-alpha images from the New Vacuum Solar Telescope, supplemented by extreme ultraviolet observations. The reconnection is seen to occur between a set of ambient chromospheric fibrils and the filament itself. This allows for the relaxation of magnetic tension in the filament by an untwisting motion, demonstrating a flux rope structure. The topology change and untwisting are also found through nonlinear force-free field modelling of the active region in combination with magnetohydrodynamic simulation. These results demonstrate a new role for reconnection in solar eruptions: the release of magnetic twist.}, language = {en} } @article{XuYanLazarian2016, author = {Xu, Siyao and Yan, Huirong and Lazarian, A.}, title = {DAMPING OF MAGNETOHYDRODYNAMIC TURBULENCE IN PARTIALLY IONIZED PLASMA: IMPLICATIONS FOR COSMIC RAY PROPAGATION}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {826}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.3847/0004-637X/826/2/166}, pages = {32}, year = {2016}, abstract = {We study the damping processes of both incompressible and compressible magnetohydrodynamic (MHD) turbulence in a partially ionized medium. We start from the linear analysis of MHD waves, applying both single-fluid and two-fluid treatments. The damping rates derived from the linear analysis are then used in determining the damping scales of MHD turbulence. The physical connection between the damping scale of MHD turbulence and the cutoff boundary of linear MHD waves is investigated. We find two branches of slow modes propagating in ions and neutrals, respectively, below the damping scale of slow MHD turbulence, and offer a thorough discussion of their propagation and dissipation behavior. Our analytical results are shown to be applicable in a variety of partially ionized interstellar medium (ISM) phases and the solar chromosphere. The importance of neutral viscosity in damping the Alfvenic turbulence in the interstellar warm neutral medium and the solar chromosphere is demonstrated. As a significant astrophysical utility, we introduce damping effects to the propagation of cosmic rays in partially ionized ISM. The important role of turbulence damping in both transit-time damping and gyroresonance is identified.}, language = {en} } @phdthesis{Xu2016, author = {Xu, Ke}, title = {Functional characterization of two MYB transcription factors, MYB95 and MYB47, in Arabidopsis thaliana}, school = {Universit{\"a}t Potsdam}, pages = {108}, year = {2016}, language = {en} } @misc{XiongStolleLuehretal.2016, author = {Xiong, Chao and Stolle, Claudia and L{\"u}hr, Hermann and Park, Jaeheung and Fejer, Bela G. and Kervalishvili, Guram N.}, title = {Scale analysis of equatorial plasma irregularities derived from Swarm constellation}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1112}, issn = {1866-8372}, doi = {10.25932/publishup-43184}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431842}, pages = {14}, year = {2016}, abstract = {In this study, we investigated the scale sizes of equatorial plasma irregularities (EPIs) using measurements from the Swarm satellites during its early mission and final constellation phases. We found that with longitudinal separation between Swarm satellites larger than 0.4°, no significant correlation was found any more. This result suggests that EPI structures include plasma density scale sizes less than 44 km in the zonal direction. During the Swarm earlier mission phase, clearly better EPI correlations are obtained in the northern hemisphere, implying more fragmented irregularities in the southern hemisphere where the ambient magnetic field is low. The previously reported inverted-C shell structure of EPIs is generally confirmed by the Swarm observations in the northern hemisphere, but with various tilt angles. From the Swarm spacecrafts with zonal separations of about 150 km, we conclude that larger zonal scale sizes of irregularities exist during the early evening hours (around 1900 LT).}, language = {en} } @article{XiongStolleLuehr2016, author = {Xiong, Chao and Stolle, Claudia and L{\"u}hr, Hermann}, title = {The Swarm satellite loss of GPS signal and its relation to ionospheric plasma irregularities}, series = {Space Weather: The International Journal of Research and Applications}, volume = {14}, journal = {Space Weather: The International Journal of Research and Applications}, publisher = {American Geophysical Union}, address = {Washington}, issn = {1542-7390}, doi = {10.1002/2016SW001439}, pages = {563 -- 577}, year = {2016}, abstract = {In this study we investigated conditions for loss of GPS signals observed by the Swarm satellites during a 2 year period, from December 2013 to November 2015. Our result shows that the Swarm satellites encountered most of the total loss of GPS signal at the ionization anomaly crests, between +/- 5 degrees and +/- 20 degrees magnetic latitude, forming two bands along the magnetic equator, and these low-latitude events mainly appear around postsunset hours from 19: 00 to 22: 00 local time. By further checking the in situ electron density measurements of Swarm, we found that practically, all the total loss of GPS signal events at low latitudes are related to equatorial plasma irregularities (EPIs) that show absolute density depletions larger than 10 x 10(11) m(-3); then, the Swarm satellites encountered for up to 95\% loss of GPS signal for at least one channel and up to 45\% tracked less than four GPS satellites (making precise orbit determination impossible). For those EPIs with density depletions less than 10 x 10(11) m(-3), the chance of tracked GPS signals less than four reduces to only 1.0\%. Swarm also observed total loss of all GPS signal at high latitudes, mainly around local noon, and these events are related to large spatial density gradients due to polar patches or increased geomagnetic/auroral activities. We further found that the loss of GPS signals were less frequent after appropriate settings of the Swarm GPS receivers had been updated. However, the more recent period of the mission, e.g., after the GPS receiver settings have been updated, also coincides with less severe electron density depletions due to the declining solar cycle, making GPS loss events less likely. We conclude that both lower electron density gradients and appropriate GPS receiver settings reduce the probability for Swarm satellites loss of GPS signals.}, language = {en} }