@article{KhelifiSarntheinNaafs2012, author = {Khelifi, N. and Sarnthein, M. and Naafs, B. D. A.}, title = {Technical note: Late Pliocene age control and composite depths at ODP Site 982, revisited}, series = {CLIMATE OF THE PAST}, volume = {8}, journal = {CLIMATE OF THE PAST}, number = {1}, publisher = {COPERNICUS GESELLSCHAFT MBH}, address = {GOTTINGEN}, issn = {1814-9324}, doi = {10.5194/cp-8-79-2012}, pages = {79 -- 87}, year = {2012}, abstract = {Ocean Drilling Program (ODP) Site 982 provided a key sediment section at Rockall Plateau for reconstructing northeast Atlantic paleoceanography and monitoring benthic delta O-18 stratigraphy over the late Pliocene to Quaternary onset of major Northern Hemisphere glaciation. A renewed hole-specific inspection of magnetostratigraphic reversals and the addition of epibenthic delta O-18 records for short Pliocene sections in holes 982A, B, and C, crossing core breaks in the delta O-18 record published for Hole 982B, now imply a major revision of composite core depths. After tuning to the orbitally tuned reference record LR04, the new composite delta O-18 record results in a hiatus, where the Kaena magnetic subchron might have been lost, and in a significant age reduction for all proxy records by 130 to 20 ky over the time span 3.2-2.7 million years ago (Ma). Our study demonstrates the general significance of reliable composite-depth scales and delta O-18 stratigraphies in ODP sediment records for generating ocean-wide correlations in paleoceanography. The new concept of age control makes the late Pliocene trends in SST (sea surface temperature) and atmospheric pCO(2) at Site 982 more consistent with various paleoclimate trends published from elsewhere in the North Atlantic.}, language = {en} } @article{KnoopsErbilErtuerk2012, author = {Knoops, Femke and Erbil, Fethiye and Ert{\"u}rk, Mustafa}, title = {Teaching patterns and trends}, 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-65845}, pages = {75 -- 79}, year = {2012}, abstract = {1. Outline 2. Definition 3. Why is it important (or not) to teach about patterns and trends? What are the strengths and weaknesses of teaching patterns and trends? 4. How were patterns and trends offered in the original assignments? 5. What did the student teacher change in practice? How did it go? 6. Suggestions for improving patterns and trends}, language = {en} } @book{UhlenwinkelKrauseHalmanetal.2012, author = {Uhlenwinkel, Anke and Krause, Uwe and Halman, Loek and Rokven, Josja and Sieben, Inge and Pažick{\´y}, Michal and Blahušiakov{\´a}, Andrea and R{\"o}per-K{\"u}hnemann, Christian and Staufenbiel, Christoph and Voz{\´a}rov{\´a}, Hana and Hintze, Katarina and Ivaška, Michal and Kallenbach, Ren{\´e} and Majer, Zdenko and R{\"o}ll, Juliane and Pisarč{\´i}k, Stanislav and Weiser, Ines and Seeger, Anett and Strehmann, Anja and Chovanov{\´a}, Katarina and Gembick{\´y}, Kamil and Nern, Luise and Cornelissen, Sebastiaan and Turgut, Pelin and Knoops, Femke and Erbil, Fethiye and Ert{\"u}rk, Mustafa and Akpinar, Seda and Maas, Desiree and Rooth, Anneke and Azar, Elif Zeynep and Erd{\"o}nmez, {\c{C}}ağlayan and Verscheijden, Desir{\´e}e and Altuntas, Kezban and Ak{\c{c}}ay, Pinar and Kools, Suzanne and Schnabel, Richard and van den Beemt, Martijn and {\c{C}}inkaya, Muhammed and Erdem, Didem Tuğ{\c{c}}e and Janssen, Robert}, title = {Teaching about the religious values of Europeans : critical reflections from the second student exchange of the EVE-project}, editor = {Uhlenwinkel, Anke}, isbn = {978-3-86956-175-2}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-59010}, publisher = {Universit{\"a}t Potsdam}, year = {2012}, abstract = {The European Values Education (EVE) project is a large-scale, cross-national, and longitudinal survey research programme on basic human values. The main topic of its second stage was religion in Europe. Student teachers of several universities in Europe worked together in multicultural exchange groups. Their results are presented in this issue.}, language = {en} } @article{WildishPavesiKetmaier2012, author = {Wildish, J. and Pavesi, Laura and Ketmaier, Valerio}, title = {Talitrid amphipods (Crustacea: Amphipoda: Talitridae) and the driftwood ecological niche a morphological and molecular study}, series = {Journal of natural history : an international journal of systematics, interactive biology and biodiversity. - London : Taylor \& Francis   1.1967 -}, volume = {46}, journal = {Journal of natural history : an international journal of systematics, interactive biology and biodiversity. - London : Taylor \& Francis   1.1967 -}, number = {43-44}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {0022-2933}, doi = {10.1080/00222933.2012.717971}, pages = {2677 -- 2700}, year = {2012}, abstract = {Coastal regions of the North East Atlantic and Mediterranean Seas have four known species of driftwood talitrids. Records are extremely scanty, often limited to the type locality and dating to 1950. We were able to study three of them, all belonging to the genus Macarorchestia, using fresh and archived samples including type material. Allometric and molecular analyses support: (1) a close relationship among all the three classically defined Macarorchestia species, (2) Macarorchestia was well separated from non-driftwood taxa, and (3) a putative new driftwood talitrid discovered during this study was not closely related to Macarorchestia. Genetic divergence between the new species and Macarorchestia remyi is as high as the average distance among a number of talitrid species included in the study for comparison. A key is provided to identify all three of the presently known species of Macarorchestia, using morphological characters employed in the allometric study.}, language = {en} } @article{HerzogSchickLeitenbergeretal.2012, author = {Herzog, Marc and Schick, Daniel and Leitenberger, Wolfram and Shayduk, Roman and van der Veen, Renske M. and Milne, Christopher J. and Johnson, Steven Lee and Vrejoiu, Ionela and Bargheer, Matias}, title = {Tailoring interference and nonlinear manipulation of femtosecond x-rays}, series = {New journal of physics : the open-access journal for physics}, volume = {14}, journal = {New journal of physics : the open-access journal for physics}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {1367-2630}, doi = {10.1088/1367-2630/14/1/013004}, pages = {9}, year = {2012}, abstract = {We present ultrafast x-ray diffraction (UXRD) experiments on different photoexcited oxide superlattices. All data are successfully simulated by dynamical x-ray diffraction calculations based on a microscopic model, that accounts for the linear response of phonons to the excitation laser pulse. Some Bragg reflections display a highly nonlinear strain dependence. The origin of linear and two distinct nonlinear response phenomena is discussed in a conceptually simpler model using the interference of envelope functions that describe the diffraction efficiency of the average constituent nanolayers. The combination of both models facilitates rapid and accurate simulations of UXRD experiments.}, language = {en} } @article{AndresRoskeDoeringetal.2012, author = {Andres, Dorothee and Roske, Yvette and Doering, Carolin and Heinemann, Udo and Seckler, Robert and Barbirz, Stefanie}, title = {Tail morphology controls DNA release in two Salmonella phages with one lipopolysaccharide receptor recognition system}, series = {Molecular microbiology}, volume = {83}, journal = {Molecular microbiology}, number = {6}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0950-382X}, doi = {10.1111/j.1365-2958.2012.08006.x}, pages = {1244 -- 1253}, year = {2012}, abstract = {Bacteriophages use specific tail proteins to recognize host cells. It is still not understood to molecular detail how the signal is transmitted over the tail to initiate infection. We have analysed in vitro DNA ejection in long-tailed siphovirus 9NA and short-tailed podovirus P22 upon incubation with Salmonella typhimurium lipopolysaccharide (LPS). We showed for the first time that LPS alone was sufficient to elicit DNA release from a siphovirus in vitro. Crystal structure analysis revealed that both phages use similar tailspike proteins for LPS recognition. Tailspike proteins hydrolyse LPS O antigen to position the phage on the cell surface. Thus we were able to compare in vitro DNA ejection processes from two phages with different morphologies with the same receptor under identical experimental conditions. Siphovirus 9NA ejected its DNA about 30 times faster than podovirus P22. DNA ejection is under control of the conformational opening of the particle and has a similar activation barrier in 9NA and P22. Our data suggest that tail morphology influences the efficiencies of particle opening given an identical initial receptor interaction event.}, language = {en} } @article{NeuvonenNeuvonenKochetal.2012, author = {Neuvonen, Kari and Neuvonen, Helmi and Koch, Andreas and Kleinpeter, Erich}, title = {Taft equation in the light of NBO computations introduction of a novel polar computational substituent constant scale sigma(q)* for alkyl groups}, series = {Computational and theoretical chemistry}, volume = {981}, journal = {Computational and theoretical chemistry}, number = {2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2210-271X}, doi = {10.1016/j.comptc.2011.11.044}, pages = {52 -- 58}, year = {2012}, abstract = {The validity of the Taft equation: log(k(R)/k(CH3)) = rho*sigma* + delta E-S was studied with the aid of NBO computational results concerning cyclohexyl esters RCOOC6H11 [R = Methyl, Ethyl, n-Propyl, Isopropyl, n-Butyl, Isobutyl, sec-Butyl, tert-Butyl, Neopentyl, CH(CH2CH3)(2), CH(CH3)C(CH3)(3), C(CH3)(2)CH2CH3, C(CH3)(2)C(CH3)(3), CH(CH3)(Np), CH(iPr)(tBu), C(Me)(Et)(iPr), C(Et)(2)(tBu) or C(Et)(iPr)(tBu)]. It was proved that the sigma*(alkyl) value is a composite substitutent constant including the polar and steric contributions. A novel computational sigma(q)* substituent constant scale is presented based on the NBO atomic charges of the alpha-carbon and the computational total steric exchange energies E(ster) of the cyclohexyl esters specified above. The method used offers a useful way to calculate sigma*(alkyl) values for alkyl groups for which experimental Taft's polar sigma* parameters are not available.}, language = {en} } @article{KleinpeterNeuvonenNeuvonenetal.2012, author = {Kleinpeter, Erich and Neuvonen, Kari and Neuvonen, Helmi and Koch, Andreas}, title = {Taft equation in the light of NBO computations : Introduction of a novel polar computational substituent constant scale for alkyl groups}, issn = {2210-271X}, year = {2012}, language = {en} } @phdthesis{Irgang2012, author = {Irgang, Susann}, title = {Systemic characterization of the TOR-signaling pathway in chlamydomonas reinhardtii}, address = {Potsdam}, pages = {135 S.}, year = {2012}, language = {en} } @article{HeinzJungStegmann2012, author = {Heinz, S. and Jung, I. and Stegmann, Christian}, title = {Systematic studies of the Richardson-Lucy deconvolution algorithm applied to VHE gamma data}, series = {ASTROPARTICLE PHYSICS}, volume = {36}, journal = {ASTROPARTICLE PHYSICS}, number = {1}, publisher = {ELSEVIER SCIENCE BV}, address = {AMSTERDAM}, issn = {0927-6505}, doi = {10.1016/j.astropartphys.2012.05.013}, pages = {146 -- 150}, year = {2012}, abstract = {The Richardson-Lucy deconvolution algorithm was applied to astronomical images in the very high-energy regime with photon energies above 100 GeV. Through a systematic study with respect to source significance, background level and source morphology we were able to derive optimal deconvolution parameters. The results presented show that deconvolution makes it possible to study structural details well below the angular resolution of the very high-energy gamma-ray experiment. (C) 2012 Elsevier B.V. All rights reserved.}, language = {en} } @article{GirbigGrimbsSelbig2012, author = {Girbig, Dorothee and Grimbs, Sergio and Selbig, Joachim}, title = {Systematic analysis of stability patterns in plant primary metabolism}, series = {PLoS one}, volume = {7}, journal = {PLoS one}, number = {4}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0034686}, pages = {12}, year = {2012}, abstract = {Metabolic networks are characterized by complex interactions and regulatory mechanisms between many individual components. These interactions determine whether a steady state is stable to perturbations. Structural kinetic modeling (SKM) is a framework to analyze the stability of metabolic steady states that allows the study of the system Jacobian without requiring detailed knowledge about individual rate equations. Stability criteria can be derived by generating a large number of structural kinetic models (SK-models) with randomly sampled parameter sets and evaluating the resulting Jacobian matrices. Until now, SKM experiments applied univariate tests to detect the network components with the largest influence on stability. In this work, we present an extended SKM approach relying on supervised machine learning to detect patterns of enzyme-metabolite interactions that act together in an orchestrated manner to ensure stability. We demonstrate its application on a detailed SK-model of the Calvin-Benson cycle and connected pathways. The identified stability patterns are highly complex reflecting that changes in dynamic properties depend on concerted interactions between several network components. In total, we find more patterns that reliably ensure stability than patterns ensuring instability. This shows that the design of this system is strongly targeted towards maintaining stability. We also investigate the effect of allosteric regulators revealing that the tendency to stability is significantly increased by including experimentally determined regulatory mechanisms that have not yet been integrated into existing kinetic models.}, language = {en} } @article{KleinpeterLazarevaShainyanetal.2012, author = {Kleinpeter, Erich and Lazareva, Nataliya F. and Shainyan, Bagrat A. and Schilde, Uwe and Chipania, Nina N.}, title = {Synthesis, Molecular Structure, Conformational Analysis, and Chemical Properties of Silicon-Containing Derivatives of Quinolizidine}, issn = {0022-3263}, year = {2012}, language = {en} } @article{LazarevaShainyanSchildeetal.2012, author = {Lazareva, Nataliya F. and Shainyan, Bagrat A. and Schilde, Uwe and Chipanina, Nina N. and Oznobikhina, Larisa P. and Albanov, Alexander I. and Kleinpeter, Erich}, title = {Synthesis, molecular structure, conformational analysis, and chemical properties of silicon-containing derivatives of quinolizidine}, series = {The journal of organic chemistry}, volume = {77}, journal = {The journal of organic chemistry}, number = {5}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo202658n}, pages = {2382 -- 2388}, year = {2012}, abstract = {A silicon analog of quinolizidine 3,3,7,7-tetramethylhexahydro-1H-[1,4,2]oxazasilino[4,5-d][1,4,2]oxazasilin-9a-yl)methanol 3 was synthesized. X-ray diffraction analysis confirmed the trans configuration and low temperature NMR spectroscopy both the flexibility (barrier of interconversion 5.8 kcal mol(-1)) and the conformational equilibrium (chair-chair and chair-twist conformers) of the compound. The relative stability of the different isomers/conformers of 3 was calculated also at the MP2/6-311G(d,p) level of theory. Intra- and intermolecular hydrogen bonding in 3 and the appropriate equilibrium between free and self-associated molecules was studied in solvents of different polarity. Both the N-methyl quaternary ammonium salt and the O-trimethylsilyl derivative of 3 could be obtained and their structure determined.}, language = {en} } @article{NajafpourHillierShamkhalietal.2012, author = {Najafpour, Mohammad Mahdi and Hillier, Warwick and Shamkhali, Amir Nasser and Amini, Mojtaba and Beckmann, Katrin and Jaglicic, Zvonko and Jagodic, Marko and Strauch, Peter and Moghaddam, Atefeh Nemati and Beretta, Giangiacomo and Bagherzadeh, Mojtaba}, title = {Synthesis, characterization, DFT studies and catalytic activities of manganese(II) complex with 1,4-bis(2,2 ':6,2 ''-terpyridin-4 '-yl) benzene}, series = {Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry}, volume = {41}, journal = {Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry}, number = {39}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-9226}, doi = {10.1039/c2dt31544k}, pages = {12282 -- 12288}, year = {2012}, abstract = {A new di-manganese complex with "back-to-back" 1,4-bis(2,2':6,2 ''-terpyridin-4'-yl) benzene ligation has been synthesized and characterised by a variety of techniques. The back-to-back ligation presents a novel new mononuclear manganese catalytic centre that functions as a heterogeneous catalysis for the evolution of oxygen in the presence of an exogenous oxidant. We discuss the synthesis and spectroscopic characterizations of this complex and propose a mechanism for oxygen evolution activity of the compound in the presence of oxone. The di-manganese complex also shows efficient and selective catalytic oxidation of sulfides in the presence of H2O2. Density functional theory calculations were used to assess the structural optimization of the complex and a proposed reaction pathway with oxone. The calculations show that middle benzene ring is distorted respect to both of metallic centers, and this in turn leads to negligible resonance of electrons between two sides of complex. The calculations also indicate the unpaired electron located on oxyl-ligand emphasizes the radical mechanism of water oxidation for the system.}, language = {en} } @article{KleinpeterStojanovicMarkovicetal.2012, author = {Kleinpeter, Erich and Stojanovic, Milovan and Markovic, Rade and Baranac-Stojanovic, Marija}, title = {Synthesis of thiazolidine-fused heterocycles via exo-mode cyclizations of vinylogous N-acyliminium ions}, issn = {1477-0520}, year = {2012}, abstract = {Syntheses of thiazolidine-fused heterocycles via exo-mode cyclizations of vinylogous N-acyliminium ions incorporating heteroatom-based nucleophiles have been examined and discussed. The formation of (5,6)-membered systems was feasible with all nucleophiles tried (O, S and N), while the closing of the five-membered ring was restricted to O- and S-nucleophiles. The closure of a four-membered ring failed. Instead, the bicyclic (5,6)-membered acetal derivative and the tricyclic system with an eight-membered central ring were obtained from the substrates containing O and S nucleophilic moieties, respectively. The reaction outcome and stereochemistry are rationalized using quantum chemical calculations at B3LYP/6-31G(d) level. The exclusive cis-stereoselectivity in the formation of (5,6)- and (5,5)-membered systems results from thermodynamic control, whereas the formation of the eight-membered ring was kinetically controlled.}, language = {en} } @article{StojanovicMarkovicKleinpeteretal.2012, author = {Stojanovic, Milovan and Markovic, Rade and Kleinpeter, Erich and Baranac-Stojanovic, Marija}, title = {Synthesis of thiazolidine-fused heterocycles via exo-mode cyclizations of vinylogous N-acyliminium ions}, series = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, volume = {10}, journal = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, number = {3}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-0520}, doi = {10.1039/c1ob06451g}, pages = {575 -- 589}, year = {2012}, abstract = {Syntheses of thiazolidine-fused heterocycles via exo-mode cyclizations of vinylogous N-acyliminium ions incorporating heteroatom-based nucleophiles have been examined and discussed. The formation of (5,6)-membered systems was feasible with all nucleophiles tried (O, S and N), while the closing of the five-membered ring was restricted to O- and S-nucleophiles. The closure of a four-membered ring failed. Instead, the bicyclic (5,6)-membered acetal derivative and the tricyclic system with an eight-membered central ring were obtained from the substrates containing O and S nucleophilic moieties, respectively. The reaction outcome and stereochemistry are rationalized using quantum chemical calculations at B3LYP/6-31G(d) level. The exclusive cis-stereoselectivity in the formation of (5,6)- and (5,5)-membered systems results from thermodynamic control, whereas the formation of the eight-membered ring was kinetically controlled.}, language = {en} } @article{KleinpeterModarresiAlamInaloo2012, author = {Kleinpeter, Erich and Modarresi-Alam, Ali Reza and Inaloo, Iman Dindarloo}, title = {Synthesis of primary thiocarbamates by silica sulfuric acid as effective reagent under solid-state and solution conditions}, issn = {0022-2860}, year = {2012}, abstract = {A simple and efficient method for the conversion of alcohols and phenols to primary O-thiocarbamates and S- thiocarbamates in the absence of solvent (solvent-free condition) using silica sulfuric acid (SiO2OSO3H) as a solid acid is described. The products are easily distinguished by IR, NMR and X-ray data. X-ray data of the compounds reveal a planar trigonal orientation of the NH2 nitrogen atom with the partial C,N double-bond character and the CS or CO groups in synperiplanar position with CarylO and CalkylS moieties, respectively. Moreover, the OCSNH2 group which is perpendicular to the plane of the benzene ring in 1c and the central thiocarbamate SCONH2 group in 2b are essentially planar.}, language = {en} } @article{ModarresiAlamInalooKleinpeter2012, author = {Modarresi-Alam, Ali Reza and Inaloo, Iman Dindarloo and Kleinpeter, Erich}, title = {Synthesis of primary thiocarbamates by silica sulfuric acid as effective reagent under solid-state and solution conditions}, series = {Journal of molecular structure}, volume = {1024}, journal = {Journal of molecular structure}, number = {9}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0022-2860}, doi = {10.1016/j.molstruc.2012.05.033}, pages = {156 -- 162}, year = {2012}, abstract = {A simple and efficient method for the conversion of alcohols and phenols to primary O-thiocarbamates and S-thiocarbamates in the absence of solvent (solvent-free condition) using silica sulfuric acid (equivalent to SiO2-OSO3H) as a solid acid is described. The products are easily distinguished by IR, NMR and X-ray data. X-ray data of the compounds reveal a planar trigonal orientation of the NH2 nitrogen atom with the partial C,N double-bond character and the C=S or C=O groups in synperiplanar position with C-aryl-O and C-alkyl-S moieties, respectively. Moreover, the -O-CS-NH2 group which is perpendicular to the plane of the benzene ring in 1c and the central thiocarbamate -S-CO-NH2 group in 2b are essentially planar.}, language = {en} } @article{GoebelXieNeumannetal.2012, author = {Goebel, Ronald and Xie, Zai-Lai and Neumann, Mike and G{\"u}nter, Christina and Loebbicke, Ruben and Kubo, Shiori and Titirici, Maria-Magdalena and Giordano, Cristina and Taubert, Andreas}, title = {Synthesis of mesoporous carbon/iron carbide hybrids with unusually high surface areas from the ionic liquid precursor [Bmim][FeCl4]}, series = {CrystEngComm}, volume = {14}, journal = {CrystEngComm}, number = {15}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1466-8033}, doi = {10.1039/c2ce25064k}, pages = {4946 -- 4951}, year = {2012}, abstract = {Mesoporous carbon/iron carbide hybrid materials with surface areas reaching 800 m(2) g(-1) were synthesized via an exotemplating route using monolithic mesoporous silica as template and the ionic liquid 1-butyl-3-methylimidazolium tetrachloridoferrate(III) [Bmim][FeCl4] as carbon and iron source. After heat treatment (750 degrees C under argon) of the [Bmim][FeCl4] precursor confined within the silica matrix, the silica exotemplate was removed with HF leaving the mesoporous C/Fe3C hybrid behind. The surface areas and the pore sizes depend on the exotemplate and the surface areas a significantly larger than any other surface area reported for C/Fe3C hybrid materials so far. The approach is thus a prototype for the synthesis of high-surface area iron carbide-based hybrid materials with potential application in catalysis.}, language = {en} } @article{KoethTierschAppelhansetal.2012, author = {Koeth, Anja and Tiersch, Brigitte and Appelhans, Dietmar and Gradzielski, Michael and C{\"o}lfen, Helmut and Koetz, Joachim}, title = {Synthesis of Core-Shell Gold Nanoparticles with Maltose-Modified Poly(Ethyleneimine)}, series = {Journal of dispersion science and technology}, volume = {33}, journal = {Journal of dispersion science and technology}, number = {1-3}, publisher = {Taylor \& Francis Group}, address = {Philadelphia}, issn = {0193-2691}, doi = {10.1080/01932691.2010.530084}, pages = {52 -- 60}, year = {2012}, abstract = {The synthesis of ultrafine gold nanoparticles in presence of maltose-modified hyperbranched poly(ethyleneimines) (PEI) is described. The polymer acted as both a reducing and stabilising agent in the particle formation process. The nanoparticles were characterized by means of dynamic light scattering (DLS), transmission electron microscopy (TEM), analytical ultracentrifugation (AUC), small-angle x-ray scattering (SAXS), and small-angle neutron scattering (SANS). The mechanism of nanoparticle formation can be described in two steps. The reduction process of the Au3+ ions located in the inner coil region of the hyperbranched PEI led to the formation of a compact gold core, and is accompanied by a collapse of the polymer coil. Therefore, in the subsequent reduction process a gold-polymer hybrid shell is formed. By using the PEI of higher molar mass, core-shell gold nanoparticles of about 3.6 nm size with a more narrow size distribution and special fluorescence behavior could be synthesized.}, language = {en} }