TY  - JOUR
A1  - Andres, Dorothee
A1  - Gohlke, Ulrich
A1  - Bröker, Nina Kristin
A1  - Schulze, Stefan
A1  - Rabsch, Wolfgang
A1  - Heinemann, Udo
A1  - Barbirz, Stefanie
A1  - Seckler, Robert
T1  - An essential serotype recognition pocket on phage P22 tailspike protein forces Salmonella enterica serovar Paratyphi A O-antigen fragments to bind as nonsolution conformers
JF  - Glycobiology
N2  - Bacteriophage P22 recognizes O-antigen polysaccharides of Salmonella enterica subsp. enterica (S.) with its tailspike protein (TSP). In the serovars S. Typhimurium, S. Enteritidis, and S. Paratyphi A, the tetrasaccharide repeat units of the respective O-antigens consist of an identical main chain trisaccharide but different 3,6-dideoxyhexose substituents. Here, the epimers abequose, tyvelose and paratose determine the specific serotype. P22 TSP recognizes O-antigen octasaccharides in an extended binding site with a single 3,6-dideoxyhexose binding pocket. We have isolated S. Paratyphi A octasaccharides which were not available previously and determined the crystal structure of their complex with P22 TSP. We discuss our data together with crystal structures of complexes with S. Typhimurium and S. Enteritidis octasaccharides determined earlier. Isothermal titration calorimetry showed that S. Paratyphi A octasaccharide binds P22 TSP less tightly, with a difference in binding free energy of similar to 7 kJ mol(-1) at 20 degrees C compared with S. Typhimurium and S. Enteritidis octasaccharides. Individual protein-carbohydrate contacts were probed by amino acid replacements showing that the dideoxyhexose pocket contributes to binding of all three serotypes. However, S. Paratyphi A octasaccharides bind in a conformation with an energetically unfavorable phi/epsilon glycosidic bond angle combination. In contrast, octasaccharides from the other serotypes bind as solution-like conformers. Two water molecules are conserved in all P22 TSP complexes with octasaccharides of different serotypes. They line the dideoxyhexose binding pocket and force the S. Paratyphi A octasaccharides to bind as nonsolution conformers. This emphasizes the role of solvent as part of carbohydrate binding sites.
KW  - bacterial O-antigen
KW  - carbohydrate interaction
KW  - paratose
KW  - structural thermodynamics
KW  - tailspike protein
Y1  - 2013
U6  - https://doi.org/10.1093/glycob/cws224
SN  - 0959-6658
VL  - 23
IS  - 4
SP  - 486
EP  - 494
PB  - Oxford Univ. Press
CY  - Cary
ER  - 
TY  - THES
A1  - Anggraini, Ade
T1  - The 26 May 2006 yogyakarta earthquake, aftershocks and interactions
Y1  - 2013
CY  - Potsdam
ER  - 
TY  - THES
A1  - Anis, Muhammad Rehan
T1  - Climate change effects on overland flow
Y1  - 2013
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Anoop, Ambili
A1  - Prasad, S.
A1  - Plessen, Birgit
A1  - Basavaiah, Nathani
A1  - Gaye, B.
A1  - Naumann, R.
A1  - Menzel, P.
A1  - Weise, S.
A1  - Brauer, Achim
T1  - Palaeoenvironmental implications of evaporative gaylussite crystals from Lonar Lake, central India
JF  - Journal of quaternary science
N2  - We have undertaken petrographic, mineralogical, geochemical and isotopic investigations on carbonate minerals found within a 10-m-long core from Lonar Lake, central India, with the aim of evaluating their potential as palaeoenvironmental proxies. The core encompasses the entire Holocene and is the first well-dated high-resolution record from central India. While calcite and/or aragonite were found throughout the core, the mineral gaylussite was found only in two specific intervals (46303890 and 2040560 cal a BP). Hydrochemical and isotope data from inflowing streams and lake waters indicate that evaporitic processes play a dominant role in the precipitation of carbonates within this lake. Isotopic (18O and 13C) studies on the evaporative gaylussite crystals and residual bulk carbonates (calcite) from the long core show that evaporation is the major control on 18O enrichment in both the minerals. However, in case of 13C additional mechanisms, for example methanogenesis (gaylussite) and phytoplankton productivity (calcium carbonate), play an additional important role in some intervals. We also discuss the relevance of our investigation for palaeoclimate reconstruction and late Holocene monsoon variability.
KW  - evaporites
KW  - gaylussite
KW  - isotopes
KW  - Lonar Lake
KW  - monsoon
Y1  - 2013
U6  - https://doi.org/10.1002/jqs.2625
SN  - 0267-8179
VL  - 28
IS  - 4
SP  - 349
EP  - 359
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Anoop, Ambili
A1  - Prasad, Sushma
A1  - Krishnan, R.
A1  - Naumann, Rudolf
A1  - Dulski, Peter
T1  - Intensified monsoon and spatiotemporal changes in precipitation patterns in the NW Himalaya during the early-mid holocene
JF  - Quaternary international : the journal of the International Union for Quaternary Research
N2  - We have undertaken a high resolution palaeoclimate reconstruction on radiocarbon dated palaeolake sediments from the Spiti valley, NW Himalaya. This site lies in the climatically sensitive winter westerlies and Indian Summer Monsoon (ISM) transitional regime and provides an opportunity to reconstruct the precipitation seasonality, and extreme precipitation events that are characterised by intensified erosion. The lake sediments reveal distinct lithofacies that provide evidence of changes in depositional environment and climate during early to mid Holocene (8.7-6.1 cal ka BP). We have identified three stages during the period of lake's existence: the Stage I (8.7-7.6 cal ka BP) is marked by lake establishment; Stage II (similar to 7.6-6.8 cal ka BP) by sustained cooler periods and weakened summer monsoon, and Stage III (similar to 6.8-6.1 cal ka BP) by a shift from colder to warmer climate with stronger ISM. We have identified several short term cooler periods at ca. 8.7, 8.5, 8.3 and 7.2-6.9 cal ka BP. Based on an overview of regional climate records we show that there is an abrupt switch in precipitation seasonality ca. 6.8 cal ka BP that is followed by the onset of the intensified monsoon in the NW Himalaya. (C) 2013 Elsevier Ltd and INQUA. All rights reserved.
Y1  - 2013
U6  - https://doi.org/10.1016/j.quaint.2013.08.014
SN  - 1040-6182
VL  - 313
SP  - 74
EP  - 84
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Archambault, S.
A1  - Arlen, T.
A1  - Aune, T.
A1  - Behera, B.
A1  - Beilicke, M.
A1  - Benbow, W.
A1  - Bird, R.
A1  - Bouvier, A.
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Byrum, K.
A1  - Cesarini, A.
A1  - Ciupik, L.
A1  - Connolly, M. P.
A1  - Cui, W.
A1  - Errando, M.
A1  - Falcone, A.
A1  - Federici, Simone
A1  - Feng, Q.
A1  - Finley, J. P.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Galante, N.
A1  - Gall, D.
A1  - Gillanders, G. H.
A1  - Griffin, S.
A1  - Grube, J.
A1  - Gyuk, G.
A1  - Hanna, D.
A1  - Holder, J.
A1  - Hughes, G.
A1  - Humensky, T. B.
A1  - Kaaret, P.
A1  - Kertzman, M.
A1  - Khassen, Y.
A1  - Kieda, D.
A1  - Krawczynski, H.
A1  - Krennrich, F.
A1  - Kumar, S.
A1  - Lang, M. J.
A1  - Madhavan, A. S.
A1  - Maier, G.
A1  - Majumdar, P.
A1  - McArthur, S.
A1  - McCann, A.
A1  - Millis, J.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - de Bhroithe, A. O'Faolain
A1  - Ong, R. A.
A1  - Otte, A. N.
A1  - Park, N.
A1  - Perkins, J. S.
A1  - Pohl, Martin
A1  - Popkow, A.
A1  - Prokoph, H.
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reyes, L. C.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Saxon, D. B.
A1  - Sembroski, G. H.
A1  - Smith, A. W.
A1  - Staszak, D.
A1  - Telezhinsky, Igor O.
A1  - Theiling, M.
A1  - Varlotta, A.
A1  - Vassiliev, V. V.
A1  - Vincent, S.
A1  - Wakely, S. P.
A1  - Weekes, T. C.
A1  - Weinstein, A.
A1  - Welsing, R.
A1  - Williams, D. A.
A1  - Zitzer, B.
A1  - Boettcher, Markus
A1  - Fegan, S. J.
A1  - Fortin, P.
A1  - Halpern, J. P.
A1  - Kovalev, Y. Y.
A1  - Lister, M. L.
A1  - Liu, J.
A1  - Pushkarev, A. B.
A1  - Smith, P. S.
T1  - Discovery of a new tev Gamma-Ray source - VER J0521+211
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We report the detection of a new TeV gamma-ray source, VER J0521+211, based on observations made with the VERITAS imaging atmospheric Cherenkov Telescope Array. These observations were motivated by the discovery of a cluster of >30 GeV photons in the first year of Fermi Large Area Telescope observations. VER J0521+211 is relatively bright at TeV energies, with a mean photon flux of (1.93 +/- 0.13(stat) +/- 0.78(sys)) x 10(-11) cm(-2) s(-1) above 0.2 TeV during the period of the VERITAS observations. The source is strongly variable on a daily timescale across all wavebands, from optical to TeV, with a peak flux corresponding to similar to 0.3 times the steady Crab Nebula flux at TeV energies. Follow-up observations in the optical and X-ray bands classify the newly discovered TeV source as a BL Lac-type blazar with uncertain redshift, although recent measurements suggest z = 0.108. VER J0521+211 exhibits all the defining properties of blazars in radio, optical, X-ray, and gamma-ray wavelengths.
KW  - BL Lacertae objects: individual (VER J0521+211)
KW  - gamma rays: galaxies
Y1  - 2013
U6  - https://doi.org/10.1088/0004-637X/776/2/69
SN  - 0004-637X
SN  - 1538-4357
VL  - 776
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Archambault, S.
A1  - Beilicke, M.
A1  - Benbow, W.
A1  - Berger, K.
A1  - Bird, R.
A1  - Bouvier, A.
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Byrum, K.
A1  - Cerruti, M.
A1  - Chen, Xuhui
A1  - Ciupik, L.
A1  - Connolly, M. P.
A1  - Cui, W.
A1  - Duke, C.
A1  - Dumm, J.
A1  - Errando, M.
A1  - Falcone, A.
A1  - Federici, Simone
A1  - Feng, Q.
A1  - Finley, J. P.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Galante, N.
A1  - Gillanders, G. H.
A1  - Griffin, S.
A1  - Griffiths, S. T.
A1  - Grube, J.
A1  - Gyuk, G.
A1  - Hanna, D.
A1  - Holder, J.
A1  - Hughes, G.
A1  - Humensky, T. B.
A1  - Kaaret, P.
A1  - Kertzman, M.
A1  - Khassen, Y.
A1  - Kieda, D.
A1  - Krawczynski, H.
A1  - Lang, M. J.
A1  - Madhavan, A. S.
A1  - Maier, G.
A1  - Majumdar, P.
A1  - McArthur, S.
A1  - McCann, A.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - Nieto, D.
A1  - de Bhroithe, A. O'Faolain
A1  - Ong, R. A.
A1  - Otte, A. N.
A1  - Pandel, D.
A1  - Park, N.
A1  - Perkins, J. S.
A1  - Pohl, Martin
A1  - Popkow, A.
A1  - Prokoph, H.
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Rajotte, J.
A1  - Reyes, L. C.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Sembroski, G. H.
A1  - Sheidaei, F.
A1  - Smith, A. W.
A1  - Staszak, D.
A1  - Telezhinsky, Igor O.
A1  - Theiling, M.
A1  - Tucci, J. V.
A1  - Tyler, J.
A1  - Varlotta, A.
A1  - Vincent, S.
A1  - Wakely, S. P.
A1  - Weekes, T. C.
A1  - Weinstein, A.
A1  - Williams, D. A.
A1  - Zitzer, B.
A1  - McCollough, M. L.
T1  - Veritas observatons of the microquasar cygnus  X-3
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We report results from TeV gamma-ray observations of the microquasar Cygnus X-3. The observations were made with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) over a time period from 2007 June 11 to 2011 November 28. VERITAS is most sensitive to gamma rays at energies between 85 GeV and 30 TeV. The effective exposure time amounts to a total of about 44 hr, with the observations covering six distinct radio/X-ray states of the object. No significant TeV gamma-ray emission was detected in any of the states, nor with all observations combined. The lack of a positive signal, especially in the states where GeV gamma rays were detected, places constraints on TeV gamma-ray production in Cygnus X-3. We discuss the implications of the results.
KW  - acceleration of particles
KW  - binaries: close
KW  - gamma rays: stars
KW  - X-rays: individual (Cygnus X-3)
Y1  - 2013
U6  - https://doi.org/10.1088/0004-637X/779/2/150
SN  - 0004-637X
SN  - 1538-4357
VL  - 779
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Arlen, T.
A1  - Aune, T.
A1  - Beilicke, M.
A1  - Benbow, W.
A1  - Bouvier, A.
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Cesarini, A.
A1  - Ciupik, L.
A1  - Connolly, M. P.
A1  - Cui, W.
A1  - Dickherber, R.
A1  - Dumm, J.
A1  - Errando, M.
A1  - Falcone, A.
A1  - Federici, S.
A1  - Feng, Q.
A1  - Finley, J. P.
A1  - Finnegan, G.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Galante, N.
A1  - Gall, D.
A1  - Griffin, S.
A1  - Grube, J.
A1  - Gyuk, G.
A1  - Hanna, D.
A1  - Holder, J.
A1  - Humensky, T. B.
A1  - Kaaret, P.
A1  - Karlsson, N.
A1  - Kertzman, M.
A1  - Khassen, Y.
A1  - Kieda, D.
A1  - Krawczynski, H.
A1  - Krennrich, F.
A1  - Maier, G.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - Nelson, T.
A1  - de Bhroithe, A. O'Faolain
A1  - Ong, R. A.
A1  - Orr, M.
A1  - Park, N.
A1  - Perkins, J. S.
A1  - Pichel, A.
A1  - Pohl, Martin
A1  - Prokoph, H.
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reyes, L. C.
A1  - Reynolds, P. T.
A1  - Roache, E.
A1  - Saxon, D. B.
A1  - Schroedter, M.
A1  - Sembroski, G. H.
A1  - Staszak, D.
A1  - Telezhinsky, Igor O.
A1  - Tesic, G.
A1  - Theiling, M.
A1  - Tsurusaki, K.
A1  - Varlotta, A.
A1  - Vincent, S.
A1  - Wakely, S. P.
A1  - Weekes, T. C.
A1  - Weinstein, A.
A1  - Welsing, R.
A1  - Williams, D. A.
A1  - Zitzer, B.
A1  - Jorstad, S. G.
A1  - MacDonald, N. R.
A1  - Marscher, A. P.
A1  - Smith, P. S.
A1  - Walker, R. C.
A1  - Hovatta, T.
A1  - Richards, J.
A1  - Max-Moerbeck, W.
A1  - Readhead, A.
A1  - Lister, M. L.
A1  - Kovalev, Y. Y.
A1  - Pushkarev, A. B.
A1  - Gurwell, M. A.
A1  - Lahteenmaki, A.
A1  - Nieppola, E.
A1  - Tornikoski, M.
A1  - Jarvela, E.
T1  - Rapid TeV Gamma-Ray flaring of bl lacertae
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We report on the detection of a very rapid TeV gamma-ray flare from BL Lacertae on 2011 June 28 with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The flaring activity was observed during a 34.6 minute exposure, when the integral flux above 200 GeV reached (3.4 +/- 0.6) x 10(-6) photons m(-2) s(-1), roughly 125% of the Crab Nebula flux measured by VERITAS. The light curve indicates that the observations missed the rising phase of the flare but covered a significant portion of the decaying phase. The exponential decay time was determined to be 13 +/- 4 minutes, making it one of the most rapid gamma-ray flares seen from a TeV blazar. The gamma-ray spectrum of BL Lacertae during the flare was soft, with a photon index of 3.6 +/- 0.4, which is in agreement with the measurement made previously by MAGIC in a lower flaring state. Contemporaneous radio observations of the source with the Very Long Baseline Array revealed the emergence of a new, superluminal component from the core around the time of the TeV gamma-ray flare, accompanied by changes in the optical polarization angle. Changes in flux also appear to have occurred at optical, UV, and GeV gamma-ray wavelengths at the time of the flare, although they are difficult to quantify precisely due to sparse coverage. A strong flare was seen at radio wavelengths roughly four months later, which might be related to the gamma-ray flaring activities. We discuss the implications of these multiwavelength results.
KW  - galaxies: active
KW  - galaxies: individual (BL Lacertae, VER J2202+422)
KW  - gamma rays: galaxies
Y1  - 2013
U6  - https://doi.org/10.1088/0004-637X/762/2/92
SN  - 0004-637X
VL  - 762
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Arnison, Paul G.
A1  - Bibb, Mervyn J.
A1  - Bierbaum, Gabriele
A1  - Bowers, Albert A.
A1  - Bugni, Tim S.
A1  - Bulaj, Grzegorz
A1  - Camarero, Julio A.
A1  - Campopiano, Dominic J.
A1  - Challis, Gregory L.
A1  - Clardy, Jon
A1  - Cotter, Paul D.
A1  - Craik, David J.
A1  - Dawson, Michael
A1  - Dittmann-Thünemann, Elke
A1  - Donadio, Stefano
A1  - Dorrestein, Pieter C.
A1  - Entian, Karl-Dieter
A1  - Fischbach, Michael A.
A1  - Garavelli, John S.
A1  - Goeransson, Ulf
A1  - Gruber, Christian W.
A1  - Haft, Daniel H.
A1  - Hemscheidt, Thomas K.
A1  - Hertweck, Christian
A1  - Hill, Colin
A1  - Horswill, Alexander R.
A1  - Jaspars, Marcel
A1  - Kelly, Wendy L.
A1  - Klinman, Judith P.
A1  - Kuipers, Oscar P.
A1  - Link, A. James
A1  - Liu, Wen
A1  - Marahiel, Mohamed A.
A1  - Mitchell, Douglas A.
A1  - Moll, Gert N.
A1  - Moore, Bradley S.
A1  - Mueller, Rolf
A1  - Nair, Satish K.
A1  - Nes, Ingolf F.
A1  - Norris, Gillian E.
A1  - Olivera, Baldomero M.
A1  - Onaka, Hiroyasu
A1  - Patchett, Mark L.
A1  - Piel, Jörn
A1  - Reaney, Martin J. T.
A1  - Rebuffat, Sylvie
A1  - Ross, R. Paul
A1  - Sahl, Hans-Georg
A1  - Schmidt, Eric W.
A1  - Selsted, Michael E.
A1  - Severinov, Konstantin
A1  - Shen, Ben
A1  - Sivonen, Kaarina
A1  - Smith, Leif
A1  - Stein, Torsten
A1  - Suessmuth, Roderich D.
A1  - Tagg, John R.
A1  - Tang, Gong-Li
A1  - Truman, Andrew W.
A1  - Vederas, John C.
A1  - Walsh, Christopher T.
A1  - Walton, Jonathan D.
A1  - Wenzel, Silke C.
A1  - Willey, Joanne M.
A1  - van der Donk, Wilfred A.
T1  - Ribosomally synthesized and post-translationally modified peptide natural products overview and recommendations for a universal nomenclature
JF  - Natural product reports : a journal of current developments in bio-organic chemistry
N2  - This review presents recommended nomenclature for the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), a rapidly growing class of natural products. The current knowledge regarding the biosynthesis of the >20 distinct compound classes is also reviewed, and commonalities are discussed.
Y1  - 2013
U6  - https://doi.org/10.1039/c2np20085f
SN  - 0265-0568
VL  - 30
IS  - 1
SP  - 108
EP  - 160
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - INPR
A1  - Asendorpf, Jens B.
A1  - Conner, Mark
A1  - De Fruyt, Filip
A1  - De Houwer, Jan
A1  - Denissen, Jaap J. A.
A1  - Fiedler, Klaus
A1  - Fiedler, Susann
A1  - Funder, David C.
A1  - Kliegl, Reinhold
A1  - Nosek, Brian A.
A1  - Perugini, Marco
A1  - Roberts, Brent W.
A1  - Schmitt, Manfred
A1  - Van Aken, Marcel A. G.
A1  - Weber, Hannelore
A1  - Wicherts, Jelte M.
T1  - Replication is more than hitting the lottery twice
T2  - European journal of personality
N2  - The main goal of our target article was to provide concrete recommendations for improving the replicability of research findings. Most of the comments focus on this point. In addition, a few comments were concerned with the distinction between replicability and generalizability and the role of theory in replication. We address all comments within the conceptual structure of the target article and hope to convince readers that replication in psychological science amounts to much more than hitting the lottery twice.
Y1  - 2013
SN  - 0890-2070
VL  - 27
IS  - 2
SP  - 138
EP  - 144
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Asendorpf, Jens B.
A1  - Conner, Mark
A1  - De Fruyt, Filip
A1  - De Houwer, Jan
A1  - Denissen, Jaap J. A.
A1  - Fiedler, Klaus
A1  - Fiedler, Susann
A1  - Funder, David C.
A1  - Kliegl, Reinhold
A1  - Nosek, Brian A.
A1  - Perugini, Marco
A1  - Roberts, Brent W.
A1  - Schmitt, Manfred
A1  - vanAken, Marcel A. G.
A1  - Weber, Hannelore
A1  - Wicherts, Jelte M.
T1  - Recommendations for increasing replicability in psychology
JF  - European journal of personality
N2  - Replicability of findings is at the heart of any empirical science. The aim of this article is to move the current replicability debate in psychology towards concrete recommendations for improvement. We focus on research practices but also offer guidelines for reviewers, editors, journal management, teachers, granting institutions, and university promotion committees, highlighting some of the emerging and existing practical solutions that can facilitate implementation of these recommendations. The challenges for improving replicability in psychological science are systemic. Improvement can occur only if changes are made at many levels of practice, evaluation, and reward.
KW  - replicability
KW  - confirmation bias
KW  - publication bias
KW  - generalizability
KW  - research transparency
Y1  - 2013
U6  - https://doi.org/10.1002/per.1919
SN  - 0890-2070
VL  - 27
IS  - 2
SP  - 108
EP  - 119
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - THES
A1  - Ast, Cindy
T1  - Design and photophysical characterization of single fluorophore-based ammonium sensors
Y1  - 2013
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Ast, Sandra
A1  - Fischer, Tobias
A1  - Müller, Holger
A1  - Mickler, Wulfhard
A1  - Schwichtenberg, Mathias
A1  - Rurack, Knut
A1  - Holdt, Hans-Jürgen
T1  - Integration of the 1,2,3-Triazole "Click" Motif as a potent signalling element in metal ion responsive fluorescent probes
JF  - Chemistry - a European journal
N2  - In a systematic approach we synthesized a new series of fluorescent probes incorporating donoracceptor (D-A) substituted 1,2,3-triazoles as conjugative -linkers between the alkali metal ion receptor N-phenylaza-[18]crown-6 and different fluorophoric groups with different electron-acceptor properties (4-naphthalimide, meso-phenyl-BODIPY and 9-anthracene) and investigated their performance in organic and aqueous environments (physiological conditions). In the charge-transfer (CT) type probes 1, 2 and 7, the fluorescence is almost completely quenched by intramolecular CT (ICT) processes involving charge-separated states. In the presence of Na+ and K+ ICT is interrupted, which resulted in a lighting-up of the fluorescence in acetonitrile. Among the investigated fluoroionophores, compound 7, which contains a 9-anthracenyl moiety as the electron-accepting fluorophore, is the only probe which retains light-up features in water and works as a highly K+/Na+-selective probe under simulated physiological conditions. Virtually decoupled BODIPY-based 6 and photoinduced electron transfer (PET) type probes 35, where the 10-substituted anthracen-9-yl fluorophores are connected to the 1,2,3-triazole through a methylene spacer, show strong ion-induced fluorescence enhancement in acetonitrile, but not under physiological conditions. Electrochemical studies and theoretical calculations were used to assess and support the underlying mechanisms for the new ICT and PET 1,2,3-triazole fluoroionophores.
KW  - charge transfer
KW  - click chemistry
KW  - electron transfer
KW  - fluorescent probes
KW  - metal ions
Y1  - 2013
U6  - https://doi.org/10.1002/chem.201201575
SN  - 0947-6539
VL  - 19
IS  - 9
SP  - 2990
EP  - 3005
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Ast, Sandra
A1  - Schwarze, Thomas
A1  - Müller, Holger
A1  - Sukhanov, Aleksey
A1  - Michaelis, Stefanie
A1  - Wegener, Joachim
A1  - Wolfbeis, Otto S.
A1  - Körzdörfer, Thomas
A1  - Dürkop, Axel
A1  - Holdt, Hans-Jürgen
T1  - A highly K+-Selective Phenylaza-[18]crown-6-Lariat-Ether-Based Fluoroionophore and its application in the sensing of K+ Ions with an optical sensor film and in cells
JF  - Chemistry - a European journal
N2  - Herein, we report the synthesis of two phenylaza-[18]crown-6 lariat ethers with a coumarin fluorophore (1 and 2) and we reveal that compound 1 is an excellent probe for K+ ions under simulated physiological conditions. The presence of a 2-methoxyethoxy lariat group at the ortho position of the anilino moiety is crucial to the substantially increased stability of compounds 1 and 2 over their lariat-free phenylaza-[18] crown-6 ether analogues. Probe 1 shows a high K+/Na+ selectivity and a 2.5-fold fluorescence enhancement was observed in the presence of 100 mm K+ ions. A fluorescent membrane sensor, which was prepared by incorporating probe 1 into a hydrogel, showed a fully reversible response, a response time of 150 s, and a signal change of 7.8% per 1 mm K+ within the range 1-10 mm K+. The membrane was easily fabricated (only a single sensing layer on a solid polyester support), yet no leaching was observed. Moreover, compound 1 rapidly permeated into cells, was cytocompatible, and was suitable for the fluorescent imaging of K+ ions on both the extracellular and intracellular levels.
KW  - crown compounds
KW  - fluorescence
KW  - gels
KW  - potassium
KW  - sensors
Y1  - 2013
U6  - https://doi.org/10.1002/chem.201302350
SN  - 0947-6539
SN  - 1521-3765
VL  - 19
IS  - 44
SP  - 14911
EP  - 14917
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - THES
A1  - Attermeyer, Katrin
T1  - Effects of allochthonous organic carbon on bacterial metabolism and community structure, and consequences for carbon cycling in smal, shallow lakes
Y1  - 2013
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Attermeyer, Katrin
A1  - Premke, Katrin
A1  - Hornick, Thomas
A1  - Hilt, Sabine
A1  - Grossart, Hans-Peter
T1  - Ecosystem-level studies of terrestrial carbon reveal contrasting bacterial metabolism in different aquatic habitats
JF  - Ecology : a publication of the Ecological Society of America
N2  - In aquatic systems, terrestrial dissolved organic matter (t-DOM) is known to stimulate bacterial activities in the water column, but simultaneous effects of autumnal leaf input on water column and sediment microbial dynamics in littoral zones of lakes remain largely unknown. The study's objective was to determine the effects of leaf litter on bacterial metabolism in the littoral water and sediment, and subsequently, the consequences for carbon cycling and food web dynamics. Therefore, in late fall, we simultaneously measured water and sediment bacterial metabolism in the littoral zone of a temperate shallow lake after adding terrestrial particulate organic matter (t-POM), namely, maize leaves. To better evaluate bacterial production (BP) and community respiration (CR) in sediments, we incubated sediment cores with maize leaves of different quality (nonleached and leached) under controlled laboratory conditions. Additionally, to quantify the incorporated leaf carbon into microbial biomass, we determined carbon isotopic ratios of fatty acids from sediment and leaf-associated microbes from a laboratory experiment using C-13-enriched beech leaves. The concentrations of dissolved organic carbon (DOC) increased significantly in the lake after the addition of maize leaves, accompanied by a significant increase in water BP. In contrast, sediment BP declined after an initial peak, showing no positive response to t-POM addition. Sediment BP and CR were also not stimulated by t-POM in the laboratory experiment, either in short-term or in long-term incubations, except for a short increase in CR after 18 hours. However, this increase might have reflected the metabolism of leaf-associated microorganisms. We conclude that the leached t-DOM is actively incorporated into microbial biomass in the water column but that the settling leached t-POM (t-POML) does not enter the food web via sediment bacteria. Consequently, t-POML is either buried in the sediment or introduced into the aquatic food web via microorganisms (bacteria and fungi) directly associated with t-POML and via benthic macroinvertebrates by shredding of t-POML. The latter pathway represents a benthic shortcut which efficiently transfers t-POML to higher trophic levels.
KW  - bacterial production
KW  - carbon turnover
KW  - community respiration
KW  - leaf litter
KW  - phospholipid-derived fatty acid
KW  - PLFA
KW  - Schulzensee
KW  - Germany
KW  - sediments
KW  - shallow lakes
KW  - stable isotopes
KW  - terrestrial subsidies
Y1  - 2013
U6  - https://doi.org/10.1890/13-0420.1
SN  - 0012-9658
SN  - 1939-9170
VL  - 94
IS  - 12
SP  - 2754
EP  - 2766
PB  - Wiley
CY  - Washington
ER  - 
TY  - JOUR
A1  - Awasthi, Neha
A1  - Ritschel, Thomas
A1  - Lipowsky, Reinhard
A1  - Knecht, Volker
T1  - Standard gibbs energies of formation and equilibrium constants from ab-initio calculations covalent dimerization of NO2 and synthesis of NH3
JF  - The journal of chemical thermodynamics
N2  - Standard quantum chemical methods are used for accurate calculation of thermochemical properties such as enthalpies of formation, entropies and Gibbs energies of formation. Equilibrium reactions are widely investigated and experimental measurements often lead to a range of reaction Gibbs energies and equilibrium constants. It is useful to calculate these equilibrium properties from quantum chemical methods in order to address the experimental differences. Furthermore, most standard calculation methods differ in accuracy and feasibility of the system size. Hence, asystematic comparison of equilibrium properties calculated with different numerical algorithms would provide a useful reference. We select two well-known gas phase equilibrium reactions with small molecules: covalent dimer formation of NO2 (2NO(2) reversible arrow N2O4) and the synthesis of NH3 (N-2 + 3 H-2 reversible arrow 2NH(3)). We test four quantum chemical methods denoted by G3B3, CBS-APNO, W1 and CCSD(T) with aug-cc-pVXZ basis sets (X = 2, 3, and 4), to obtain thermochemical data for NO2, N2O4, and NH3. The calculated standard formation Gibbs energies Delta(f)G degrees are used to calculate standard reaction Gibbs energies Delta(r)G degrees and standard equilibrium constants K-eq for the two reactions. Standard formation enthalpies Delta H-f degrees are calculated in a more reliable way using high-level methods such as W1 and CCSD(T). Standard entropies S degrees for the molecules are calculated well within the range of experiments for all methods, however, the values of standard formation Gibbs energies Delta(f)G degrees show some dependence on the choice of the method. High-level methods perform better for the calculation of molecular energies, however, simpler methods such as G3B3 and CBS-APNO perform quite well in the calculation of total reaction energies and equilibrium constants, provided that the chemical species involved do not exhibit molecular geometries that are difficult to handle by the applied method. The temperature dependence of standard reaction Gibbs energy Delta(r)G degrees for the NH3 reaction is discussed by using the calculated standard formation Gibbs energies Delta(f)G degrees of the reaction species at 298.15 K. The corresponding equilibrium constant K-eq as a function of temperature is found to be close to experimental values.
KW  - Equilibrium constants
KW  - Thermochemical properties
KW  - Ab-initio calculations
Y1  - 2013
U6  - https://doi.org/10.1016/j.jct.2013.03.011
SN  - 0021-9614
VL  - 62
IS  - 3
SP  - 211
EP  - 221
PB  - Elsevier
CY  - London
ER  - 
TY  - THES
A1  - Bach, Christoph
T1  - Improving statistical seismicity models
T1  - Weiterentwicklung statistischer Seismizitätsmodelle
N2  - Several mechanisms are proposed to be part of the earthquake triggering process, including static stress interactions and dynamic stress transfer. Significant differences of these mechanisms are particularly expected in the spatial distribution of aftershocks. However, testing the different hypotheses is challenging because it requires the consideration of the large uncertainties involved in stress calculations as well as the appropriate consideration of secondary aftershock triggering which is related to stress changes induced by smaller pre- and aftershocks. In order to evaluate the forecast capability of different mechanisms, I take the effect of smaller--magnitude earthquakes into account by using the epidemic type aftershock sequence (ETAS) model where the spatial probability distribution of direct aftershocks, if available, is correlated to alternative source information and mechanisms. Surface shaking, rupture geometry, and slip distributions are tested. As an approximation of the shaking level, ShakeMaps are used which are available in near real-time after a mainshock and thus could be used for first-order forecasts of the spatial aftershock distribution. Alternatively, the use of empirical decay laws related to minimum fault distance is tested and Coulomb stress change calculations based on published and random slip models. For comparison, the likelihood values of the different model combinations are analyzed in the case of several well-known aftershock sequences (1992 Landers, 1999 Hector Mine, 2004 Parkfield). The tests show that the fault geometry is the most valuable information for improving aftershock forecasts. Furthermore, they reveal that static stress maps can additionally improve the forecasts of off--fault aftershock locations, while the integration of ground shaking data could not upgrade the results significantly. In the second part of this work, I focused on a procedure to test the information content of inverted slip models. This allows to quantify the information gain if this kind of data is included in aftershock forecasts. For this purpose, the ETAS model based on static stress changes, which is introduced in part one, is applied. The forecast ability of the models is systematically tested for several earthquake sequences and compared to models using random slip distributions. The influence of subfault resolution and segment strike and dip is tested. Some of the tested slip models perform very good, in that cases almost no random slip models are found to perform better. Contrastingly, for some of the published slip models, almost all random slip models perform better than the published slip model. Choosing a different subfault resolution hardly influences the result, as long the general slip pattern is still reproducible. Whereas different strike and dip values strongly influence the results depending on the standard deviation chosen, which is applied in the process of randomly selecting the strike and dip values.
N2  - Verschiedene Mechanismen werden für das Triggern von Erdbeben verantwortlich gemacht, darunter statische Spannungsänderungen und dynamischer Spannungstransfer. Deutliche Unterschiede zwischen diesen Mechanismen werden insbesondere in der räumlichen Nachbebenverteilung erwartet. Es ist allerdings schwierig diese Hypothesen zu überprüfen, da die großen Unsicherheiten der Spannungsberechnungen berücksichtigt werden müssen, ebenso wie das durch lokale sekundäre Spannungsänderungen hervorgerufene initiieren von sekundären Nachbeben. Um die Vorhersagekraft verschiedener Mechanismen zu beurteilen habe ich die Effekte von Erdbeben kleiner Magnitude durch Benutzen des "epidemic type aftershock sequence" (ETAS) Modells berücksichtigt. Dabei habe ich die Verteilung direkter Nachbeben, wenn verfügbar, mit alternativen Herdinformationen korreliert. Bodenbewegung, Bruchgeometrie und Slipmodelle werden getestet. Als Aproximation der Bodenbewegung werden ShakeMaps benutzt. Diese sind nach großen Erdbeben nahezu in Echtzeit verfügbar und können daher für vorläufige Vorhersagen der räumlichen Nachbebenverteilung benutzt werden. Alternativ können empirische Beziehungen als Funktion der minimalen Distanz zur Herdfläche benutzt werden oder Coulomb Spannungsänderungen basierend auf publizierten oder zufälligen Slipmodellen. Zum Vergleich werden die Likelihood Werte der Hybridmodelle im Falle mehrerer bekannter Nachbebensequenzen analysiert (1992 Landers, 1999 Hector Mine, 2004 Parkfield). Die Tests zeigen, dass die Herdgeometrie die wichtigste Zusatzinformation zur Verbesserung der Nachbebenvorhersage ist. Des Weiteren können statische Spannungsänderungen besonders die Vorhersage von Nachbeben in größerer Entfernung zur Bruchfläche verbessern, wohingegen die Einbeziehung von Bodenbewegungskarten die Ergebnisse nicht wesentlich verbessern konnte. Im zweiten Teil meiner Arbeit führe ich ein neues Verfahren zur Untersuchung des Informationsgehaltes von invertierten Slipmodellen ein. Dies ermöglicht die Quantifizierung des Informationsgewinns, der durch Einbeziehung dieser Daten in Nachbebenvorhersagen entsteht. Hierbei wird das im ersten Teil eingeführte erweiterte ETAS Modell benutzt, welches statische Spannungsänderung zur Vorhersage der räumlichen Nachbebenverteilung benutzt. Die Vorhersagekraft der Modelle wird systematisch anhand mehrerer Erdbebensequenzen untersucht und mit Modellen basierend auf zufälligen Slipverteilungen verglichen. Der Einfluss der Veränderung der Auflösung der Slipmodelle, sowie Streich- und Fallwinkel der Herdsegmente wird untersucht. Einige der betrachteten Slipmodelle korrelieren sehr gut, in diesen Fällen werden kaum zufällige Slipmodelle gefunden, welche die Nachbebenverteilung besser erklären. Dahingegen korrelieren bei einigen Beispielen nahezu alle zufälligen Slipmodelle besser als das publizierte Modell. Das Verändern der Auflösung der Bewegungsmodelle hat kaum Einfluss auf die Ergebnisse, solange die allgemeinen Slipmuster noch reproduzierbar sind, d.h. ein bis zwei größere Slipmaxima pro Segment. Dahingegen beeinflusst eine zufallsbasierte Änderung der Streich- und Fallwinkel der Segmente die Resultate stark, je nachdem welche Standardabweichung gewählt wurde.
KW  - Nachbeben
KW  - ETAS
KW  - Vorhersage
KW  - aftershock
KW  - ETAS
KW  - forecast
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-70591
ER  - 
TY  - THES
A1  - Badalyan, Artavazd
T1  - Bioelectrochemistry of molybdenum hydroxylases : aldehyde oxidoreductase PaoABC from escherichia coli and xanthine dehydrogenase from rhodobacter capsulatus
Y1  - 2013
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Badalyan, Artavazd
A1  - Neumann-Schaal, Meina
A1  - Leimkühler, Silke
A1  - Wollenberger, Ursula
T1  - A Biosensor for aromatic aldehydes comprising the mediator dependent PaoABC-Aldehyde oxidoreductase
JF  - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis
N2  - A novel aldehyde oxidoreductase (PaoABC) from Escherichia coli was utilized for the development of an oxygen insensitive biosensor for benzaldehyde. The enzyme was immobilized in polyvinyl alcohol and currents were measured for aldehyde oxidation with different one and two electron mediators with the highest sensitivity for benzaldehyde in the presence of hexacyanoferrate(III). The benzaldehyde biosensor was optimized with respect to mediator concentration, enzyme loading and pH using potassium hexacyanoferrate(III). The linear measuring range is between 0.5200 mu M benzaldehyde. In correspondence with the substrate selectivity of the enzyme in solution the biosensor revealed a preference for aromatic aldehydes and less effective conversion of aliphatic aldehydes. The biosensor is oxygen independent, which is a particularly attractive feature for application. The biosensor can be applied to detect contaminations with benzaldehyde in solvents such as benzyl alcohol, where traces of benzaldehyde in benzyl alcohol down to 0.0042?% can be detected.
KW  - Aldehyde oxidoreductase
KW  - Benzaldehyde
KW  - Biosensor
KW  - Aromatic aldehydes
KW  - Molybdenum cofactor
Y1  - 2013
U6  - https://doi.org/10.1002/elan.201200362
SN  - 1040-0397
VL  - 25
IS  - 1
SP  - 101
EP  - 108
PB  - Wiley-VCH
CY  - Weinheim
ER  -