@phdthesis{Kumke2007, author = {Kumke, Thomas}, title = {Aquatische Organismen als Indikatoren f{\"u}r quantitative Umwelt- und Klima{\"a}nderungen in der Pal{\"a}o{\"o}kologie : Methoden und Anwendungen}, publisher = {Logos-Verl.}, address = {Berlin}, isbn = {978-3-8325-1639-0}, pages = {XIV, 200 S. : Ill., graph. Darst., Kt.}, year = {2007}, language = {de} } @article{PrimusRitschelSigueenzaetal.2014, author = {Primus, Philipp-Alexander and Ritschel, Thomas and Sigueenza, Pilar Y. and Cauqui, Miguel Angel and Hernandez-Garrido, Juan Carlos and Kumke, Michael Uwe}, title = {High-resolution spectroscopy of europium-doped ceria as a tool to correlate structure and catalytic activity}, series = {The journal of physical chemistry : C, Nanomaterials and interfaces}, volume = {118}, journal = {The journal of physical chemistry : C, Nanomaterials and interfaces}, number = {40}, publisher = {American Chemical Society}, address = {Washington}, issn = {1932-7447}, doi = {10.1021/jp505467r}, pages = {23349 -- 23360}, year = {2014}, abstract = {Site-selective emission spectra of Eu3+-doped CeO2 nanoparticles up to the D-5(0) - F-7(5) transition were recorded under cryogenic conditions to identify the local structure around the Eu3+ dopants in ceria. It is found that pretreatment conditions are crucial for the redistribution of dopants from a broad variety of environments to six well-defined lattice sites. The influence of the dopant and the host structure on the catalytic activity was investigated. A relationship between structure and reactivity is discussed. It is shown that oxygen transport is most efficient in particles with a pronounced amorphous character.}, language = {en} } @article{MuellerFoerstendorfSteudtneretal.2019, author = {M{\"u}ller, Katharina and Foerstendorf, Harald and Steudtner, Robin and Tsushima, Satoru and Kumke, Michael Uwe and Lef{\`e}vre, Gr{\´e}gory and Rothe, J{\"o}rg and Mason, Harris and Szab{\´o}, Zolt{\´a}n and Yang, Ping and Adam, Christian K. R. and Andr{\´e}, R{\´e}mi and Brennenstuhl, Katlen and Chiorescu, Ion and Cho, Herman M. and Creff, Ga{\"e}lle and Coppin, Fr{\´e}d{\´e}ric and Dardenne, Kathy and Den Auwer, Christophe and Drobot, Bj{\"o}rn and Eidner, Sascha and Hess, Nancy J. and Kaden, Peter and Kremleva, Alena and Kretzschmar, Jerome and Kr{\"u}ger, Sven and Platts, James A. and Panak, Petra and Polly, Robert and Powell, Brian A. and Rabung, Thomas and Redon, Roland and Reiller, Pascal E. and R{\"o}sch, Notker and Rossberg, Andr{\´e} and Scheinost, Andreas C. and Schimmelpfennig, Bernd and Schreckenbach, Georg and Skerencak-Frech, Andrej and Sladkov, Vladimir and Solari, Pier Lorenzo and Wang, Zheming and Washton, Nancy M. and Zhang, Xiaobin}, title = {Interdisciplinary Round-Robin Test on molecular spectroscopy of the U(VI) Acetate System}, series = {ACS omega / American Chemical Society}, volume = {4}, journal = {ACS omega / American Chemical Society}, number = {5}, publisher = {American Chemical Society}, address = {Washington}, issn = {2470-1343}, doi = {10.1021/acsomega.9b00164}, pages = {8167 -- 8177}, year = {2019}, abstract = {A comprehensive molecular analysis of a simple aqueous complexing system. U(VI) acetate. selected to be independently investigated by various spectroscopic (vibrational, luminescence, X-ray absorption, and nuclear magnetic resonance spectroscopy) and quantum chemical methods was achieved by an international round-robin test (RRT). Twenty laboratories from six different countries with a focus on actinide or geochemical research participated and contributed to this scientific endeavor. The outcomes of this RRT were considered on two levels of complexity: first, within each technical discipline, conformities as well as discrepancies of the results and their sources were evaluated. The raw data from the different experimental approaches were found to be generally consistent. In particular, for complex setups such as accelerator-based X-ray absorption spectroscopy, the agreement between the raw data was high. By contrast, luminescence spectroscopic data turned out to be strongly related to the chosen acquisition parameters. Second, the potentials and limitations of coupling various spectroscopic and theoretical approaches for the comprehensive study of actinide molecular complexes were assessed. Previous spectroscopic data from the literature were revised and the benchmark data on the U(VI) acetate system provided an unambiguous molecular interpretation based on the correlation of spectroscopic and theoretical results. The multimethodologic approach and the conclusions drawn address not only important aspects of actinide spectroscopy but particularly general aspects of modern molecular analytical chemistry.}, language = {en} } @article{SchwarzeMuellerAstetal.2014, author = {Schwarze, Thomas and M{\"u}ller, Holger and Ast, Sandra and Steinbr{\"u}ck, D{\"o}rte and Eidner, Sascha and Geißler, Felix and Kumke, Michael Uwe and Holdt, Hans-J{\"u}rgen}, title = {Fluorescence lifetime-based sensing of sodium by an optode}, series = {Chemical Communications}, journal = {Chemical Communications}, editor = {Kumke, Michael Uwe}, publisher = {The Royal Society Chemistry}, address = {Cambridge}, issn = {0022-4936}, pages = {14167 -- 14170}, year = {2014}, abstract = {We report a 1,2,3-triazol fluoroionophore for detecting Na+ that shows in vitro enhancement in the Na+-induced fluorescence intensity and decay time. The Na+-selective molecule 1 was incorporated into a hydrogel as a part of a fiber optical sensor. This sensor allows the direct determination of Na+ in the range of 1-10 mM by measuring reversible fluorescence decay time changes.}, language = {en} } @article{SchwarzeMuellerAstetal.2014, author = {Schwarze, Thomas and Mueller, Holger and Ast, Sandra and Steinbr{\"u}ck, Dorte and Eidner, Sascha and Geißler, Felix and Kumke, Michael Uwe and Holdt, Hans-J{\"u}rgen}, title = {Fluorescence lifetime-based sensing of sodium by an optode}, series = {Chemical communications}, volume = {50}, journal = {Chemical communications}, number = {91}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1359-7345}, doi = {10.1039/c4cc06112h}, pages = {14167 -- 14170}, year = {2014}, abstract = {We report a 1,2,3-triazol fluoroionophore for detecting Na+ that shows in vitro enhancement in the Na+-induced fluorescence intensity and decay time. The Na+-selective molecule 1 was incorporated into a hydrogel as a part of a fiber optical sensor. This sensor allows the direct determination of Na+ in the range of 1-10 mM by measuring reversible fluorescence decay time changes.}, language = {en} } @misc{SchwarzeMuellerAstetal.2014, author = {Schwarze, Thomas and M{\"u}ller, Holger and Ast, Sandra and Steinbr{\"u}ck, D{\"o}rte and Eidner, Sascha and Geißler, Felix and Kumke, Michael Uwe and Holdt, Hans-J{\"u}rgen}, title = {Fluorescence lifetime-based sensing of sodium by an optode}, publisher = {The Royal Society of Chemistry}, address = {Cambridge}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-76785}, pages = {14167 -- 14170}, year = {2014}, abstract = {We report a 1,2,3-triazol fluoroionophore for detecting Na+ that shows in vitro enhancement in the Na+-induced fluorescence intensity and decay time. The Na+-selective molecule 1 was incorporated into a hydrogel as a part of a fiber optical sensor. This sensor allows the direct determination of Na+ in the range of 1-10 mM by measuring reversible fluorescence decay time changes.}, language = {en} } @article{KupstatRitschelKumke2011, author = {Kupstat, Annette and Ritschel, Thomas and Kumke, Michael Uwe}, title = {Oxazine Dye-Conjugated DNA Oligonucleotides Forster Resonance Energy Transfer in View of Molecular Dye-DNA Interactions}, series = {Bioconjugate chemistry}, volume = {22}, journal = {Bioconjugate chemistry}, number = {12}, publisher = {American Chemical Society}, address = {Washington}, issn = {1043-1802}, doi = {10.1021/bc200379y}, pages = {2546 -- 2557}, year = {2011}, abstract = {In this work, the photophysical properties of two oxazine dyes (ATTO 610 and ATTO 680) covalently attached via a C6-amino linker to the 5'-end of short single-stranded as well as double-stranded DNA (ssDNA and dsDNA, respectively) of different lengths were investigated. The two oxazine dyes were chosen because of the excellent spectral overlap, the high extinction coefficients, and the high fluorescence quantum yield of ATTO 610, making them an attractive Forster resonance energy transfer (FRET) pair for bioanalytical applications in the far-red spectral range. To identify possible molecular dye-DNA interactions that cause photophysical alterations, we performed a detailed spectroscopic study, including time-resolved fluorescence anisotropy and fluorescence correlation spectroscopy measurements. As an effect of the DNA conjugation, the absorption and fluorescence maxima of both dyes were bathochromically shifted and the fluorescence decay times were increased. Moreover, the absorption of conjugated ATTO 610 was spectrally broadened, and a dual fluorescence emission was observed. Steric interactions with ssDNA as well as dsDNA were found for both dyes. The dye-DNA interactions were strengthened from ssDNA to dsDNA conjugates, pointing toward interactions with specific dsDNA domains (such as the top of the double helix). Although these interactions partially blocked the dye-linker rotation, a free (unhindered) rotational mobility of at least one dye facilitated the appropriate alignment of the transition dipole moments in doubly labeled ATTO 610/ATTO 680-dsDNA conjugates for the performance of successful FRET. Considering the high linker flexibility for the determination of the donor-acceptor distances, good accordance between theoretical and experimental FRET parameters was obtained. The considerably large Forster distance of similar to 7 nm recommends the application of this FRET pair not only for the detection of binding reactions between nucleic acids in living cells but also for monitoring interactions of larger biomolecules such as proteins.}, language = {en} } @misc{WessigHilleKumkeetal.2016, author = {Wessig, Pablo and Hille, Carsten and Kumke, Michael Uwe and Meiling, Till Thomas and Behrends, Nicole and Eisold, Ursula}, title = {Two-photon FRET pairs based on coumarin and DBD dyes}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-394445}, pages = {33510 -- 33513}, year = {2016}, abstract = {The synthesis and photophysical properties of two new FRET pairs based on coumarin as a donor and DBD dye as an acceptor are described. The introduction of a bromo atom dramatically increases the two-photon excitation (2PE) cross section providing a 2PE-FRET system, which is also suitable for 2PE-FLIM.}, language = {en} } @article{KietzkeNeherKumkeetal.2004, author = {Kietzke, Thomas and Neher, Dieter and Kumke, Michael Uwe and Montenegro, Rivelino V. D. and Landfester, Katharina and Scherf, Ullrich}, title = {A nanoparticle approach to control the phase separation in polyfluorene photovoltaic devices}, year = {2004}, abstract = {Polymer solar cell devices with nanostructured blend layers have been fabricated using single- and dual- component polymer nanospheres. Starting from an electron-donating and an electron-accepting polyfluorene derivative, PFB and F8BT, dissolved in suitable organic solvents, dispersions of solid particles with mean diameters of ca. 50 nm, containing either the pure polymer components or a mixture of PFB and F8BT in each particle, were prepared with the miniemulsion process. Photovoltaic devices based on these particles have been studied with respect to the correlation between external quantum efficiency and layer composition. It is shown that the properties of devices containing a blend of single-component PFB and F8BT particles differ significantly from those of solar cells based on blend particles, even for the same layer composition. Various factors determining the quantum efficiency in both kinds of devices are identified and discussed, taking into account the spectroscopic properties of the particles. An external quantum efficiency of ca. 4\% is measured for a device made from polymer blend nanoparticles containing PFB:F8BT at a weight ratio of 1:2 in each individual nanosphere. This is among the highest values reported so far for photovoltaic cells using this material combination}, language = {en} }