@article{MatisSchoenbornSaalfrank2015, author = {Matis, Jochen Ren{\´e} and Sch{\"o}nborn, Jan Boyke and Saalfrank, Peter}, title = {A multi-reference study of the byproduct formation for a ring-closed dithienylethene photoswitch}, series = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies}, journal = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies}, number = {17}, publisher = {The Royal Society of Chemistry}, address = {Cambridge}, issn = {1463-9076}, doi = {10.1039/C5CP00987A}, pages = {14088 -- 14095}, year = {2015}, abstract = {Photodriven molecular switches are sometimes hindered in their performance by forming byproducts which act as dead ends in sequences of switching cycles, leading to rapid fatigue effects. Understanding the reaction pathways to unwanted byproducts is a prerequisite for preventing them. This article presents a study of the photochemical reaction pathways for byproduct formation in the photochromic switch 1,2-bis-(3-thienyl)-ethene. Specifically, using single- and multi-reference methods the post-deexcitation reaction towards the byproduct in the electronic ground state S0 when starting from the S1-S0 conical intersection (CoIn), is considered in detail. We find an unusual low-energy pathway, which offers the possibility for the formation of a dyotropic byproduct. Several high-energy pathways can be excluded with high probability.}, language = {en} } @article{PrestelMoeller2015, author = {Prestel, Andreas and M{\"o}ller, Heiko Michael}, title = {Spatio-temporal control of cellular uptake achieved by photoswitchable cell-penetrating peptides}, series = {Chemical communications : ChemComm}, journal = {Chemical communications : ChemComm}, number = {52}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1364-548X}, doi = {10.1039/C5CC06848G}, pages = {701 -- 704}, year = {2015}, abstract = {The selective uptake of compounds into specific cells of interest is a major objective in cell biology and drug delivery. By incorporation of a novel, thermostable azobenzene moiety we generated peptides that can be switched optically between an inactive state and an active, cell-penetrating state with excellent spatio-temporal control.}, language = {en} } @article{KlierKumke2015, author = {Klier, Dennis Tobias and Kumke, Michael Uwe}, title = {Analysing the effect of the crystal structure on upconversion luminescence in Yb3+,Er3+-co-doped NaYF4 nanomaterials}, series = {Journal of materials chemistry C ; Materials for optical and electronic devices}, journal = {Journal of materials chemistry C ; Materials for optical and electronic devices}, number = {3}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {2050-7526}, doi = {10.1039/C5TC02218E}, pages = {11228 -- 11238}, year = {2015}, abstract = {NaYF4:Yb:Er nanoparticles (UCNP) were synthesized under mild experimental conditions to obtain a pure cubic lattice. Upon annealing at different temperatures up to Tan = 700 °C phase transitions to the hexagonal phase and back to the cubic phase were induced. The UCNP materials obtained for different Tan were characterized with respect to the lattice phase using standard XRD and Raman spectroscopy as well as steady state and time resolved upconversion luminescence. The standard techniques showed that for the annealing temperature range 300 °C < Tan < 600 °C the hexagonal lattice phase was dominant. For Tan < 300 °C hardly any change in the lattice phase could be deduced, whereas for Tan > 600 °C a back transfer to the α-phase was observed. Complementarily, the luminescence upconversion properties of the annealed UCNP materials were characterized in steady state and time resolved luminescence measurements. Distinct differences in the upconversion luminescence intensity, the spectral intensity distribution and the luminescence decay kinetics were found for the cubic and hexagonal lattice phases, respectively, corroborating the results of the standard analytical techniques used. In laser power dependent measurements of the upconversion luminescence intensity it was found that the green (G1, G2) and red (R) emission of Er3+ showed different effects of Tan on the number of required photons reflecting the differences in the population routes of different energy levels involved. Furthermore, the intensity ratio of Gfull/R is highly effected by the laser power only when the β-phase is present, whereas the G1/G2 intensity ratio is only slightly effected regardless of the crystal phase. Moreover, based on different upconversion luminescence kinetics characteristics of the cubic and hexagonal phase time-resolved area normalized emission spectra (TRANES) proved to be a very sensitive tool to monitor the phase transition between cubic and hexagonal phases. Based on the TRANES analysis it was possible to resolve the lattice phase transition in more detail for 200 °C < Tan < 300 °C, which was not possible with the standard techniques.}, language = {en} } @article{KlierKumke2015, author = {Klier, Dennis Tobias and Kumke, Michael Uwe}, title = {Upconversion NaYF4:Yb:Er nanoparticles co-doped with Gd3+ and Nd3+ for thermometry on the nanoscale}, series = {RSC Advances : an international journal to further the chemical sciences}, journal = {RSC Advances : an international journal to further the chemical sciences}, number = {5}, publisher = {RSC Publishing}, address = {London}, issn = {2046-2069}, doi = {10.1039/C5RA11502G}, pages = {67149 -- 67156}, year = {2015}, abstract = {In the present work, the upconversion luminescence properties of oleic acid capped NaYF4:Gd3+:Yb3+:Er3+ upconversion nanoparticles (UCNP) with pure β crystal phase and Nd3+ ions as an additional sensitizer were studied in the temperature range of 288 K < T < 328 K. The results of this study showed that the complex interplay of different mechanisms and effects, causing the special temperature behavior of the UCNP can be developed into thermometry on the nanoscale, e.g. to be applied in biological systems on a cellular level. The performance was improved by the use of Nd3+ as an additional dopant utilizing the cascade sensitization mechanism in tri-doped UCNP.}, language = {en} } @article{deCarvalhoMetzlerCherstvy2015, author = {de Carvalho, Sidney J. and Metzler, Ralf and Cherstvy, Andrey G.}, title = {Inverted critical adsorption of polyelectrolytes in confinement}, series = {Soft matter}, journal = {Soft matter}, number = {11}, publisher = {Royal Society of Chemistry}, address = {London}, issn = {1744-6848}, doi = {10.1039/C5SM00635J}, pages = {4430 -- 4443}, year = {2015}, abstract = {What are the fundamental laws for the adsorption of charged polymers onto oppositely charged surfaces, for convex, planar, and concave geometries? This question is at the heart of surface coating applications, various complex formation phenomena, as well as in the context of cellular and viral biophysics. It has been a long-standing challenge in theoretical polymer physics; for realistic systems the quantitative understanding is however often achievable only by computer simulations. In this study, we present the findings of such extensive Monte-Carlo in silico experiments for polymer-surface adsorption in confined domains. We study the inverted critical adsorption of finite-length polyelectrolytes in three fundamental geometries: planar slit, cylindrical pore, and spherical cavity. The scaling relations extracted from simulations for the critical surface charge density sc—defining the adsorption-desorption transition—are in excellent agreement with our analytical calculations based on the ground-state analysis of the Edwards equation. In particular, we confirm the magnitude and scaling of sc for the concave interfaces versus the Debye screening length 1/k and the extent of confinement a for these three interfaces for small ka values. For large ka the critical adsorption condition approaches the known planar limit. The transition between the two regimes takes place when the radius of surface curvature or half of the slit thickness a is of the order of 1/k. We also rationalize how sc(k) dependence gets modified for semi-flexible versus flexible chains under external confinement. We examine the implications of the chain length for critical adsorption—the effect often hard to tackle theoretically—putting an emphasis on polymers inside attractive spherical cavities. The applications of our findings to some biological systems are discussed, for instance the adsorption of nucleic acids onto the inner surfaces of cylindrical and spherical viral capsids.}, language = {en} } @article{HentrichJungingerBrunsetal.2015, author = {Hentrich, Doreen and Junginger, Mathias and Bruns, Michael and B{\"o}rner, Hans Gerhard and Brandt, Jessica and Brezesinski, Gerald and Taubert, Andreas}, title = {Interface-controlled calcium phosphate mineralization}, series = {CrystEngComm}, journal = {CrystEngComm}, number = {17}, publisher = {Royal Society of Chemistry}, address = {London}, issn = {1466-8033}, doi = {10.1039/C4CE02274B}, pages = {6901 -- 6913}, year = {2015}, abstract = {The phase behavior of an amphiphilic block copolymer based on a poly(aspartic acid) hydrophilic block and a poly(n-butyl acrylate) hydrophobic block was investigated at the air-water and air-buffer interface. The polymer forms stable monomolecular films on both subphases. At low pH, the isotherms exhibit a plateau. Compression-expansion experiments and infrared reflection absorption spectroscopy suggest that the plateau is likely due to the formation of polymer bi- or multilayers. At high pH the films remain intact upon compression and no multilayer formation is observed. Furthermore, the mineralization of calcium phosphate beneath the monolayer was studied at different pH. The pH of the subphase and thus the polymer charge strongly affects the phase behavior of the film and the mineral formation. After 4 h of mineralization at low pH, atomic force microscopy shows smooth mineral films with a low roughness. With increasing pH the mineral films become inhomogeneous and the roughness increases. Transmission electron microscopy confirms this: at low pH a few small but uniform particles form whereas particles grown at higher pH are larger and highly agglomerated. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirm the formation of calcium phosphate. The levels of mineralization are higher in samples grown at high pH.}, language = {en} } @phdthesis{Fengler2016, author = {Fengler, Anja}, title = {How the brain attunes to sentence processing}, series = {MPI series in human cognitive and brain sciences ; 174}, journal = {MPI series in human cognitive and brain sciences ; 174}, isbn = {978-3-941504-59-2}, pages = {XVI, 208}, year = {2016}, abstract = {While children acquire new words and simple sentence structures extremely fast and without much effort, the ability to process complex sentences develops rather late in life. Although the conjoint occurrence between brain-structural and brain-functional changes, the decrease of plasticity, and changes in cognitive abilities suggests a certain causality between these processes, concrete evidence for the relation between brain development, language processing, and language performance is rare. Therefore, the current dissertation investigates the tripartite relationship between behavior (in the form of language performance and cognitive maturation as prerequisite for language processing), brain structure (in the form of gray matter maturation), and brain function (in the form of brain activation evoked by complex sentence processing). Previous developmental studies indicate a missing increase of activation in accordance to sentence complexity (functional selectivity) in language-relevant brain areas in children. To determine the factors contributing to the functional development of language-relevant brain areas, different methodologies and data acquisition techniques were used to investigate the processing of center-embedded sentences in 5- and 6-year-old children, 7- and 8-year-old children, and adults. Behavioral results indicate that children between 5 and 8 years show difficulties in processing double embedded sentences and that their performance for these type of sentences is positively correlated with digit span. In 7- and 8-year-old children, it was found that especially the processing of long-distance relations between the initial phrase and its corresponding verb appears to be associated with the subject's verbal working memory capacity. In contrast, children's performance for double embedded sentences in the younger age group positively correlated with their performance in a standardized sentence comprehension test. This finding supports the hypothesis that processing difficulties in this age group may be mainly attributed to difficulties in processing case marking information. These findings are discussed with respect to current accounts of language and working memory development. A second study aimed at investigating the structural maturation of brain areas involved in sentence comprehension. To do this, whole-brain magnetic resonance images from 59 children between 5 and 8 years were collected and children's gray matter was analyzed by using voxel-based morphometry. Children's grammatical proficiency was assessed by a standardized sentence comprehension test. A confirmatory factory analysis corroborated a grammar-relevant and a verbal working memory-relevant factor underlying the measured performance. While children's ability to assign thematic roles is positively correlated with gray matter probability (GMP) in the left inferior temporal gyrus and the left inferior frontal gyrus, verbal working memory-related performance is positively correlated with GMP in the left parietal operculum extending into the posterior superior temporal gyrus. These areas have been previously shown to be differentially engaged in adults' complex sentence processing. Thus, the findings of the second study suggest a specific correspondence between children's GMP in language-relevant brain regions and differential cognitive abilities which underlie complex sentence comprehension. In a third study, functional brain activity during the processing of center-embedded sentences was investigated in three different age groups (5-6 years, 7-8 years, and adults). Although all age groups engage a qualitatively comparable network of the left pars opercularis (PO), the left inferior parietal lobe extending into the posterior superior temporal gyrus (IPL/pSTG), the supplementary motor area (SMA) and the cerebellum, functional selectivity of these regions was only observable in adults. However, functional activation of the language-related regions (PO and IPL/pSTG) predicted sentence comprehension performance for all age groups. To solve the question of the complex interplay between different maturational factors, a fourth study analyzed the predictive power of gray matter probability, verbal working memory capacity, and behavioral differences in performance for simple and complex sentence for the functional selectivity of each activated region. These analyses revealed that the establishment of the adult-like functional selectivity for complex sentences is predicted by a reduction of the left PO's gray matter probability across age groups while that of the IPL/pSTG is additionally predicted by verbal working memory capacity. Taken all findings together, the current thesis provides evidence that both structural brain maturation and verbal working memory expansion provide the basis for the emergence of functional selectivity in language-related brain regions leading to more efficient sentence processing during development.}, language = {en} } @phdthesis{Senft2015, author = {Senft, Christoph}, title = {Contemporary Indian writing in English between global fiction and transmodern historiography}, series = {Internationale Forschungen zur allgemeinen und vergleichenden Literaturwissenschaft ; 190}, journal = {Internationale Forschungen zur allgemeinen und vergleichenden Literaturwissenschaft ; 190}, publisher = {Rodopi}, address = {Leiden}, isbn = {978-90-04-30906-7}, pages = {239}, year = {2015}, abstract = {Christoph Senft provides a set of re-readings of contemporary Indian narrative texts as decolonial and pluralistic approaches to the past and thus offers a comprehensive overview of the subcontinent s literary landscape in the 21st century.}, language = {en} } @phdthesis{Liput2015, author = {Liput, Magdalena}, title = {Investigation of the biogenesis and use of ribosomes in Arabidopsis thaliana}, school = {Universit{\"a}t Potsdam}, pages = {158}, year = {2015}, language = {en} } @phdthesis{Wang2015, author = {Wang, Rong}, title = {Late quaternary climate and environmental variability inferred from terrigenous sediment records in China and the North Pacific/Bering Sea}, school = {Universit{\"a}t Potsdam}, pages = {91}, year = {2015}, language = {en} }