A5006131033- Spectroscopy and Quantum Chemical Studies
- Photoreceptor and optogenetics research
- Photosynthetic Processes and Mechanisms
- Photochemistry and Electron Transfer Studies
- Photochromic and Fluorescence Chemistry
- Physics and Engineering Research Articles
- Laser-Matter Interactions and Applications
- Spectroscopy Techniques in Biomedical and Chemical Research
- DNA and Nucleic Acid Chemistry
- Advanced biosensing and bioanalysis techniques
- Mass Spectrometry Techniques and Applications
- X-ray Diffraction in Crystallography
- Molecular spectroscopy and chirality
- Crystallization and Solubility Studies
- Spectroscopy and Laser Applications
- Advanced Fiber Laser Technologies
- bioluminescence and chemiluminescence research
- Molecular Junctions and Nanostructures
- Advanced Chemical Physics Studies
- Ocular and Laser Science Research
- Porphyrin and Phthalocyanine Chemistry
- Algal biology and biofuel production
- Engineering and Materials Science Studies
- Light effects on plants
- Radical Photochemical Reactions
Ludwig-Maximilians-Universität München
2015-2025
Center for Integrated Protein Science Munich
2013-2025
Technical University of Munich
1985-2020
LMU Klinikum
2002-2014
Max Planck Institute of Molecular Physiology
2001-2013
Technische Universität Berlin
2006-2009
Institut de Chimie Moléculaire de Reims
2009
Centre National de la Recherche Scientifique
2009
Université de Reims Champagne-Ardenne
2009
Florida International University
2008
Femtosecond time-resolved infrared spectroscopy was used to study the formation of cyclobutane dimers in all-thymine oligodeoxynucleotide (dT) 18 by ultraviolet light at 272 nanometers. The appearance marker bands spectra indicates that are fully formed ∼1 picosecond after excitation. ultrafast this mutagenic photolesion points an excited-state reaction is approximately barrierless for bases properly oriented instant absorption. low quantum yield photoreaction proposed result from infrequent...
In neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's (PD) and prion diseases, deposits of aggregated disease-specific proteins are found. Oligomeric aggregates presumed to be the key neurotoxic agent. Here we describe novel oligomer modulator anle138b [3-(1,3-benzodioxol-5-yl)-5-(3-bromophenyl)-1H-pyrazole], an aggregation inhibitor developed based on a systematic high-throughput screening campaign combined with medicinal chemistry optimization. vitro, blocked...
The vibrational cooling of azobenzene after photoisomerization is investigated by time resolved IR spectroscopy with femtosecond resolution. Transient difference spectra were obtained in a frequency range where phenyl ring modes and the central N=N-stretching mode absorbs. experimental data are discussed terms simple theoretical model which was derived order to account for off-diagonal anharmonicity between high-frequency bath remaining low-frequency polyatomic molecule. It shown that these...
The initial electron transfer steps in the photosynthetic reaction center of purple bacterium Rhodobacter sphaeroides have been investigated by femtosecond time-resolved spectroscopy. experimental data taken at various wavelengths demonstrate existence least four intermediate states within first nanosecond. difference spectra intermediates and transient photodichroism are fully consistent with a sequential four-step model primary transfer: Light absorption special pair P leads to state P*....
The primary electron transfer in reaction centers of Rhodobacter sphaeroides is studied by subpicosecond absorption spectroscopy with polarized light the spectral range 920-1040 nm. Here bacteriochlorophyll anion radical has an band while other pigments center have vanishing ground-state absorption. transient data exhibit a pronounced 0.9-ps kinetic component which shows strong dichroism. Evaluation yields angle between transition moments special pair and species related 26 +/- 8 degrees....
Femtosecond time-resolved spectroscopy on model peptides with built-in light switches combined computer simulation of light-triggered motions offers an attractive integrated approach toward the understanding peptide conformational dynamics. It was applied to monitor light-induced relaxation dynamics occurring subnanosecond time scales in a that backbone-cyclized azobenzene derivative as optical switch and spectroscopic probe. The femtosecond spectra permit clear distinguishing...
Significance The high photostability of single nucleobases is related to the rapid disposal UV excitation energy from high-lying electronic states into heat, preventing damaging reactions. However, in biological important DNA strands, further long-living excited are found. With femtosecond vibrational spectroscopy, these now identified as charge-separated states, which delocalized along strand. charge separation directed by redox potential involved bases and thus encoded sequence. presence...
Controlling the internal motions of molecules by outside stimuli is a decisive task for generation responsive and complex molecular behavior functionality. Light-induced structural changes photoswitches are special high interest due to ease signal application repeatability. Typically use one reaction coordinate in their switching process change between two more or less-defined states. Here we report on new twisted hemithioindigo enabling different coordinates be used process. Depending...
How life developed in its earliest stages is a central but notoriously difficult question science. The lifeforms likely used reduced set of codon sequences that were progressively completed over time, driven by chemical, physical, and combinatorial constraints. However, despite importance for prebiotic chemistry, UV radiation has not been considered selection pressure the evolution early sequences. In this proof-of-principle study, we quantified susceptibility large pools DNA protogenomes...
We present an improved design of amplified Er:fiber laser system for the generation intense femtosecond pulses. By properly controlling influence optical nonlinearities inside a stretched pulse amplifier, spectrum is broadened to over 100 nm. The pulses are recompressed 65 fs. A linearly polarized output 110 mW obtained at 67 MHz repetition rate. As first application, we report octave-spanning supercontinuum short piece highly nonlinear fiber. Self-referencing detection carrier-envelope...
Ultrafast IR spectroscopy is used to monitor the nonequilibrium backbone dynamics of a cyclic peptide in amide I vibrational range with picosecond time resolution. A conformational change induced by means photoswitch integrated into backbone. Although main completed after only 20 ps, subsequent equilibration new region space continues for times >16 ns. Relaxation and processes occur on discrete hierarchy scales. Albeit possessing few degrees freedom compared protein, behaves highly...
The applicability and limits of time-resolved transillumination to determine the internal details biological tissues are investigated by phantom experiments. By means line scans across a sharp edge, spatial resolution (Δx) its dependence on time-gate width (Δt) can be determined. Additionally, measurements completely absorbing bead pairs embedded in turbid medium demonstrate physical more realistic case. benefit time is especially high for with comparatively small reduced scattering...
Light induced changes of absorption in semiconductor-doped glasses are studied on the femtosecond and picosecond time scale. Extremely rapid recovery times 200 fs found when carriers excited with large excess energy (500 meV) above edge glasses. Excitation close to band results a slower constant τ≂100 ps.