@misc{LoehmannsroebenBeckHildebrandtetal.2006, author = {L{\"o}hmannsr{\"o}ben, Hans-Gerd and Beck, Michael and Hildebrandt, Niko and Schm{\"a}lzlin, Elmar and van Dongen, Joost T.}, title = {New challenges in biophotonics : laser-based fluoroimmuno analysis and in-vivo optical oxygen monitoring}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-10120}, year = {2006}, abstract = {Two examples of our biophotonic research utilizing nanoparticles are presented, namely laser-based fluoroimmuno analysis and in-vivo optical oxygen monitoring. Results of the work include significantly enhanced sensitivity of a homogeneous fluorescence immunoassay and markedly improved spatial resolution of oxygen gradients in root nodules of a legume species.}, subject = {Sauerstoff}, language = {en} } @misc{NiederkruegerSalbBecketal.2006, author = {Niederkr{\"u}ger, Matthias and Salb, Christian and Beck, Michael and Hildebrandt, Niko and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Marowsky, Gerd}, title = {Improvement of a fluorescence immunoassay with a compact diode-pumped solid state laser at 315 nm}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-10150}, year = {2006}, abstract = {We demonstrate the improvement of fluorescence immunoassay (FIA) diagnostics in deploying a newly developed compact diode-pumped solid state (DPSS) laser with emission at 315 nm. The laser is based on the quasi-three-level transition in Nd:YAG at 946 nm. The pulsed operation is either realized by an active Q-switch using an electro-optical device or by introduction of a Cr4+:YAG saturable absorber as passive Q-switch element. By extra-cavity second harmonic generation in different nonlinear crystal media we obtained blue light at 473 nm. Subsequent mixing of the fundamental and the second harmonic in a β-barium-borate crystal provided pulsed emission at 315 nm with up to 20 μJ maximum pulse energy and 17 ns pulse duration. Substitution of a nitrogen laser in a FIA diagnostics system by the DPSS laser succeeded in considerable improvement of the detection limit. Despite significantly lower pulse energies (7 μJ DPSS laser versus 150 μJ nitrogen laser), in preliminary investigations the limit of detection was reduced by a factor of three for a typical FIA.}, subject = {Immunoassay}, language = {en} } @misc{DoscheMicklerLoehmannsroebenetal.2007, author = {Dosche, Carsten and Mickler, Wulfhard and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Agenet, Nicolas and Vollhardt, K. Peter C.}, title = {Photoinduced electron transfer in [N]phenylenes}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-12463}, year = {2007}, abstract = {First studies of electron transfer in [N]phenylenes were performed in bimolecular quenching reactions of angular [3]- and triangular [4]phenylene with various electron acceptors. The relation between the quenching rate constants kq and the free energy change of the electron transfer (ΔG0CS ) could be described by the Rehm-Weller equation. From the experimental results, a reorganization energy λ of 0.7 eV was derived. Intramolecular electron transfer reactions were studied in an [N]phenylene bichomophore and a corresponding reference compound. Fluorescence lifetime and quantum yield of the bichromophor display a characteristic dependence on the solvent polarity, whereas the corresponding values of the reference compound remain constant. From the results, a nearly isoenergonic ΔG0CS can be determined. As the triplet quantum yield is nearly independent of the polarity, charge recombination leads to the population of the triplet state.}, language = {en} } @misc{ReichLoehmannsroebenSchael2003, author = {Reich, Oliver and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Schael, Frank}, title = {Optical sensing with photon density waves: investigation of model media}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-13147}, year = {2003}, abstract = {Investigations with frequency domain photon density waves allow elucidation of absorption and scattering properties of turbid media. The temporal and spatial propagation of intensity modulated light with frequencies up to more than 1 GHz can be described by the P1 approximation to the Boltzmann transport equation. In this study, we establish requirements for the appropriate choice of turbid model media and characterize mixtures of isosulfan blue as absorber and polystyrene beads as scatterer. For these model media, the independent determination of absorption and reduced scattering coefficients over large absorber and scatterer concentration ranges is demonstrated with a frequency domain photon density wave spectrometer employing intensity and phase measurements at various modulation frequencies.}, language = {en} } @misc{LoehmannsroebenKantorKumkeetal.2005, author = {L{\"o}hmannsr{\"o}ben, Hans-Gerd and Kantor, Zoltan and Kumke, Michael Uwe and Schm{\"a}lzlin, Elmar and Reich, Oliver}, title = {OPQS - optische Prozess- und Qualit{\"a}ts-Sensorik}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-13205}, year = {2005}, abstract = {Im vorliegenden Beitrag wird an Hand dreier Beispiele der Einsatz von optischer Sensorik zur Produktcharakterisierung dargestellt, n{\"a}mlich Untersuchungen zum O2-Gehalt in Fruchts{\"a}ften, zur Isotopiesignatur von CO2 in Mineralw{\"a}ssern und zu Lichtstreueigenschaften eines Sonnenschutzmittels. Inhalt: Bestimmung von O2 mit Lumineszenzsonden Isotopenselektive Bestimmung von CO2 mit TDLAS Optische Charakterisierung stark streuender Materialien mit Photonendichtewellen}, language = {de} }