76
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Risch P, Pfeifer T, Segrestaa J, Fretz H, Pothier J. Verification of the Major Metabolic Oxidation Path for the Naphthoyl Group in Chemoattractant Receptor-Homologous Molecule Expressed on Th2 Cells (CRTh2) Antagonist 2-(2-(1-Naphthoyl)-8-fluoro-3,4-dihydro-1H-pyrido[4,3-b]indol-5(2H)-yl)acetic Acid (Setipiprant/ACT-129968). J Med Chem 2015; 58:8011-35. [PMID: 26398218 DOI: 10.1021/acs.jmedchem.5b00824] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Various racemic and enantioenriched (trans)-X,Y-dihydroxy-X,Y-dihydronaphthoyl analogues as well as X-hydroxy-naphthoyl analogues of CRTh2 antagonist 2-(2-(1-naphthoyl)-8-fluoro-3,4-dihydro-1H-pyrido[4,3-b]indol-5(2H)-yl)acetic acid (1, Setipiprant/ACT-129968) were synthesized in order to gain insight into regio- and enantioselectivity of the metabolic oxidation of 1 and to verify the structures of four metabolites that were proposed earlier in a clinical ADME study. Analytical data of the synthetic standards were compared with data from samples of biological origin. The two major metabolites M7 and M9 were unambiguously verified as 2-(2-((trans)-3,4-dihydroxy-3,4-dihydronaphthalene-1-carbonyl)- and 2-(2-((trans)-5,6-dihydroxy-5,6-dihydronaphthalene-1-carbonyl)-8-fluoro-3,4-dihydro-1H-pyrido[4,3-b]indol-5(2H)-yl)acetic acid, respectively, each composed of two enantiomers with 68% and 44% ee in favor of (+)-(3S,4S)-M7 and (+)-(5S,6S)-M9, respectively. Likewise, minor metabolites M3 and M13 were identified as 2-(8-fluoro-2-(5-hydroxy-1-naphthoyl)- and 2-(8-fluoro-2-(4-hydroxy-1-naphthoyl)-1,2,3,4-tetrahydro-5H-pyrido[4,3-b]indol-5-yl)acetic acid, respectively.
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77
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Schmöger L, Schwarz M, Baumann TM, Versolato OO, Piest B, Pfeifer T, Ullrich J, Schmidt PO, López-Urrutia JRC. Deceleration, precooling, and multi-pass stopping of highly charged ions in Be⁺ Coulomb crystals. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:103111. [PMID: 26520944 DOI: 10.1063/1.4934245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Preparing highly charged ions (HCIs) in a cold and strongly localized state is of particular interest for frequency metrology and tests of possible spatial and temporal variations of the fine structure constant. Our versatile preparation technique is based on the generic modular combination of a pulsed ion source with a cryogenic linear Paul trap. Both instruments are connected by a compact beamline with deceleration and precooling properties. We present its design and commissioning experiments regarding these two functionalities. A pulsed buncher tube allows for the deceleration and longitudinal phase-space compression of the ion pulses. External injection of slow HCIs, specifically Ar(13+), into the linear Paul trap and their subsequent retrapping in the absence of sympathetic cooling is demonstrated. The latter proved to be a necessary prerequisite for the multi-pass stopping of HCIs in continuously laser-cooled Be(+) Coulomb crystals.
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78
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Blättermann A, Ott C, Kaldun A, Ding T, Stooß V, Laux M, Rebholz M, Pfeifer T. In situ characterization of few-cycle laser pulses in transient absorption spectroscopy. OPTICS LETTERS 2015; 40:3464-3467. [PMID: 26258333 DOI: 10.1364/ol.40.003464] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Attosecond transient absorption spectroscopy has thus far been lacking the capability to simultaneously characterize the intense laser pulses at work within a time-resolved quantum-dynamics experiment. However, precise knowledge of these pulses is key to extracting quantitative information in strong-field highly nonlinear light-matter interactions. Here, we introduce and experimentally demonstrate an ultrafast metrology tool based on the time-delay-dependent phase shift imprinted on a strong-field-driven resonance. Since we analyze the signature of the laser pulse interacting with the absorbing spectroscopy target, the laser pulse duration and intensity are determined in situ. As we also show, this approach allows for the quantification of time-dependent bound-state dynamics in one and the same experiment. In the future, such experimental data will facilitate more precise tests of strong-field dynamics theories.
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79
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Liu Z, Cavaletto SM, Ott C, Meyer K, Mi Y, Harman Z, Keitel CH, Pfeifer T. Phase Reconstruction of Strong-Field Excited Systems by Transient-Absorption Spectroscopy. PHYSICAL REVIEW LETTERS 2015; 115:033003. [PMID: 26230787 DOI: 10.1103/physrevlett.115.033003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Indexed: 06/04/2023]
Abstract
The evolution of a V-type three-level system is studied, whose two resonances are coherently excited and coupled by two ultrashort laser pump and probe pulses, separated by a varying time delay. We relate the quantum dynamics of the excited multilevel system to the absorption spectrum of the transmitted probe pulse. In particular, by analyzing the quantum evolution of the system, we interpret how atomic phases are differently encoded in the time-delay-dependent spectral absorption profiles when the pump pulse either precedes or follows the probe pulse. This scheme is experimentally applied to atomic Rb, whose fine-structure-split 5s (2)S{1/2}→5p(2)P{1/2} and 5s(2)S_{1/2}→5p(2)P{3/2} transitions are driven by the combined action of a pump pulse of variable intensity and a delayed probe pulse. The provided understanding of the relationship between quantum phases and absorption spectra represents an important step towards full time-dependent phase reconstruction (quantum holography) of bound-state wave packets in strong-field light-matter interactions with atoms, molecules, and solids.
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80
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Heeg KP, Ott C, Schumacher D, Wille HC, Röhlsberger R, Pfeifer T, Evers J. Interferometric phase detection at x-ray energies via Fano resonance control. PHYSICAL REVIEW LETTERS 2015; 114:207401. [PMID: 26047250 DOI: 10.1103/physrevlett.114.207401] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Indexed: 06/04/2023]
Abstract
Modern x-ray light sources promise access to structure and dynamics of matter in largely unexplored spectral regions. However, the desired information is encoded in the light intensity and phase, whereas detectors register only the intensity. This phase problem is ubiquitous in crystallography and imaging and impedes the exploration of quantum effects at x-ray energies. Here, we demonstrate phase-sensitive measurements characterizing the quantum state of a nuclear two-level system at hard x-ray energies. The nuclei are initially prepared in a superposition state. Subsequently, the relative phase of this superposition is interferometrically reconstructed from the emitted x rays. Our results form a first step towards x-ray quantum state tomography and provide new avenues for structure determination and precision metrology via x-ray Fano interference.
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81
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Woltsche N, Pfeifer T, Petru E, Haas J, Pickel H. Ab welcher Tumorgröße ist beim operablen Zervixkarzinom parametraner Befall zu erwarten? Geburtshilfe Frauenheilkd 2015. [DOI: 10.1055/s-0035-1548627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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82
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Schnorr K, Senftleben A, Schmid G, Rudenko A, Kurka M, Meyer K, Foucar L, Kübel M, Kling MF, Jiang YH, Düsterer S, Treusch R, Schröter CD, Ullrich J, Pfeifer T, Moshammer R. Multiple ionization and fragmentation dynamics of molecular iodine studied in IR-XUV pump-probe experiments. Faraday Discuss 2014; 171:41-56. [PMID: 25415043 DOI: 10.1039/c4fd00031e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ionization and fragmentation dynamics of iodine molecules (I(2)) are traced using very intense (∼10(14) W cm(-2)) ultra-short (∼60 fs) light pulses with 87 eV photons of the Free-electron LASer at Hamburg (FLASH) in combination with a synchronized femtosecond optical laser. Within a pump-probe scheme the IR pulse initiates a molecular fragmentation and then, after an adjustable time delay, the system is exposed to an intense FEL pulse. This way we follow the creation of highly-charged molecular fragments as a function of time, and probe the dynamics of multi-photon absorption during the transition from a molecule to individual atoms.
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83
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Fahrmayr C, König J, Auge D, Mieth M, Münch K, Segrestaa J, Pfeifer T, Treiber A, Fromm M. Phase I and II metabolism and MRP2-mediated export of bosentan in a MDCKII-OATP1B1-CYP3A4-UGT1A1-MRP2 quadruple-transfected cell line. Br J Pharmacol 2014; 169:21-33. [PMID: 23387445 DOI: 10.1111/bph.12126] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 12/05/2012] [Accepted: 12/16/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Hepatic uptake (e.g. by OATP1B1), phase I and II metabolism (e.g. by CYP3A4, UGT1A1) and subsequent biliary excretion (e.g. by MRP2) are key determinants for the pharmacokinetics of numerous drugs. However, stably transfected cell models for the simultaneous investigation of transport and phase I and II metabolism of drugs are lacking. EXPERIMENTAL APPROACH A newly established quadruple-transfected MDCKII-OATP1B1-CYP3A4-UGT1A1-MRP2 cell line was used to investigate metabolism and transcellular transport of the endothelin receptor antagonist bosentan. KEY RESULTS Intracellular accumulation of bosentan equivalents (i.e. parent compound and metabolites) was significantly lower in all cell lines expressing MRP2 compared to cell lines lacking this transporter (P < 0.001). Accordingly, considerably higher amounts of bosentan equivalents were detectable in the apical compartments of cell lines with MRP2 expression (P < 0.001). HPLC and LC-MS measurements revealed that mainly unchanged bosentan accumulated in intracellular and apical compartments. Furthermore, the phase I metabolites Ro 48-5033 and Ro 47-8634 were detected intracellularly in cell lines expressing CYP3A4. Additionally, a direct glucuronide of bosentan could be identified intracellularly in cell lines expressing UGT1A1 and in the apical compartments of cell lines expressing UGT1A1 and MRP2. CONCLUSIONS AND IMPLICATIONS These in vitro data indicate that bosentan is a substrate of UGT1A1. Moreover, the efflux transporter MRP2 mediates export of bosentan and most likely also of bosentan glucuronide in the cell system. Taken together, cell lines simultaneously expressing transport proteins and metabolizing enzymes represent additional useful tools for the investigation of the interplay of transport and metabolism of drugs.
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84
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Schnorr K, Senftleben A, Kurka M, Rudenko A, Schmid G, Pfeifer T, Meyer K, Kübel M, Kling MF, Jiang YH, Treusch R, Düsterer S, Siemer B, Wöstmann M, Zacharias H, Mitzner R, Zouros TJM, Ullrich J, Schröter CD, Moshammer R. Electron rearrangement dynamics in dissociating I(2)^(n+) molecules accessed by extreme ultraviolet pump-probe experiments. PHYSICAL REVIEW LETTERS 2014; 113:073001. [PMID: 25170702 DOI: 10.1103/physrevlett.113.073001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Indexed: 05/11/2023]
Abstract
The charge rearrangement in dissociating I_{2}^{n+} molecules is measured as a function of the internuclear distance R using extreme ultraviolet pulses delivered by the free-electron laser in Hamburg. Within an extreme ultraviolet pump-probe scheme, the first pulse initiates dissociation by multiply ionizing I_{2}, and the delayed probe pulse further ionizes one of the two fragments at a given time, thus triggering charge rearrangement at a well-defined R. The electron transfer between the fragments is monitored by analyzing the delay-dependent ion kinetic energies and charge states. The experimental results are in very good agreement with predictions of the classical over-the-barrier model demonstrating its validity in a thus far unexplored quasimolecular regime relevant for free-electron laser, plasma, and chemistry applications.
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85
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Kaldun A, Ott C, Blättermann A, Laux M, Meyer K, Ding T, Fischer A, Pfeifer T. Extracting phase and amplitude modifications of laser-coupled Fano resonances. PHYSICAL REVIEW LETTERS 2014; 112:103001. [PMID: 24679285 DOI: 10.1103/physrevlett.112.103001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Indexed: 06/03/2023]
Abstract
Fano line shapes observed in absorption spectra encode information on the amplitude and phase of the optical dipole response. A change in the Fano line shape, e.g., by interaction with short-pulsed laser fields, allows us to extract dynamical modifications of the amplitude and phase of the coupled excited quantum states. We introduce and apply this physical mechanism to near-resonantly coupled doubly excited states in helium. This general approach provides a physical understanding of the laser-induced spectral shift of absorption-line maxima on a sub-laser-cycle time scale as they are ubiquitously observed in attosecond transient-absorption measurements.
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86
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Schnorr K, Senftleben A, Kurka M, Rudenko A, Foucar L, Schmid G, Broska A, Pfeifer T, Meyer K, Anielski D, Boll R, Rolles D, Kübel M, Kling MF, Jiang YH, Mondal S, Tachibana T, Ueda K, Marchenko T, Simon M, Brenner G, Treusch R, Scheit S, Averbukh V, Ullrich J, Schröter CD, Moshammer R. Time-resolved measurement of interatomic coulombic decay in Ne2. PHYSICAL REVIEW LETTERS 2013; 111:093402. [PMID: 24033032 DOI: 10.1103/physrevlett.111.093402] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Indexed: 06/02/2023]
Abstract
The lifetime of interatomic Coulombic decay (ICD) [L. S. Cederbaum et al., Phys. Rev. Lett. 79, 4778 (1997)] in Ne2 is determined via an extreme ultraviolet pump-probe experiment at the Free-Electron Laser in Hamburg. The pump pulse creates a 2s inner-shell vacancy in one of the two Ne atoms, whereupon the ionized dimer undergoes ICD resulting in a repulsive Ne+(2p(-1))-Ne+(2p(-1)) state, which is probed with a second pulse, removing a further electron. The yield of coincident Ne+-Ne2+ pairs is recorded as a function of the pump-probe delay, allowing us to deduce the ICD lifetime of the Ne2(+)(2s(-1)) state to be (150±50) fs, in agreement with quantum calculations.
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87
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Fischer A, Sperl A, Cörlin P, Schönwald M, Rietz H, Palacios A, González-Castrillo A, Martín F, Pfeifer T, Ullrich J, Senftleben A, Moshammer R. Electron localization involving doubly excited states in broadband extreme ultraviolet ionization of H2. PHYSICAL REVIEW LETTERS 2013; 110:213002. [PMID: 23745865 DOI: 10.1103/physrevlett.110.213002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Indexed: 06/02/2023]
Abstract
Dissociative single ionization of H(2) induced by extreme ultraviolet photons from an attosecond pulse train has been studied in a kinematically complete experiment. Depending on the electron kinetic energy and the alignment of the molecule with respect to the laser polarization axis, we observe pronounced asymmetries in the relative emission directions of the photoelectron and the H(+) ion. The energy-dependent asymmetry pattern is explained by a semiclassical model and further validated by fully quantum mechanical calculations, both in very good agreement with the experiment.
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88
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Ott C, Kaldun A, Raith P, Meyer K, Laux M, Evers J, Keitel CH, Greene CH, Pfeifer T. Lorentz meets Fano in spectral line shapes: a universal phase and its laser control. Science 2013; 340:716-20. [PMID: 23661754 DOI: 10.1126/science.1234407] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Symmetric Lorentzian and asymmetric Fano line shapes are fundamental spectroscopic signatures that quantify the structural and dynamical properties of nuclei, atoms, molecules, and solids. This study introduces a universal temporal-phase formalism, mapping the Fano asymmetry parameter q to a phase φ of the time-dependent dipole response function. The formalism is confirmed experimentally by laser-transforming Fano absorption lines of autoionizing helium into Lorentzian lines after attosecond-pulsed excitation. We also demonstrate the inverse, the transformation of a naturally Lorentzian line into a Fano profile. A further application of this formalism uses quantum-phase control to amplify extreme-ultraviolet light resonantly interacting with He atoms. The quantum phase of excited states and its response to interactions can thus be extracted from line-shape analysis, with applications in many branches of spectroscopy.
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89
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Nagel PM, Robinson JS, Harteneck BD, Pfeifer T, Abel MJ, Prell JS, Neumark DM, Kaindl RA, Leone SR. Surface plasmon assisted electron acceleration in photoemission from gold nanopillars. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2012.03.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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90
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Zhang Y, Meyer K, Ott C, Pfeifer T. Passively phase-stable, monolithic, all-reflective two-dimensional electronic spectroscopy based on a four-quadrant mirror. OPTICS LETTERS 2013; 38:356-358. [PMID: 23381436 DOI: 10.1364/ol.38.000356] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A design for a passively phase-stable two-dimensional electronic spectroscopy experiment, based on a four-quadrant mirror concept, is introduced. The setup, which is particularly simple and robust, achieves subwavelength stability without the need for active stabilization or diffractive optical elements. Since only reflective optical components are used, the setup is suitable for few-cycle laser pulses and ultrabroad-bandwidth light in the ultraviolet, visible, and near-IR regions, with the capability to be used under grazing incidence for soft x ray or x-ray light at free-electron lasers.
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91
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Ott C, Kaldun A, Raith P, Meyer K, Laux M, Zhang Y, Hagstotz S, Ding T, Heck R, Pfeifer T. Time-resolved spectroscopy of doubly-excited states in helium. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20134102023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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92
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Ott C, Kaldun A, Raith P, Meyer K, Laux M, Zhang Y, Hagstotz S, Ding T, Heck R, Pfeifer T. Ponderomotive dressing of doubly-excited states with intensity-controlled laser light. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20134102022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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93
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Meyer K, Ott C, Raith P, Kaldun A, Jiang Y, Senftleben A, Kurka M, Moshammer R, Ullrich J, Pfeifer T. Enhancing temporal resolution in pump-probe experiments with noisy pulses. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20134102001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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94
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Raith P, Ott C, Anderson CP, Kaldun A, Meyer K, Laux M, Zhang Y, Pfeifer T. Fractional high-harmonic combs by attosecond-precision split-spectrum pulse control. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20134101007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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95
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Meyer K, Ott C, Raith P, Kaldun A, Jiang Y, Senftleben A, Kurka M, Moshammer R, Ullrich J, Pfeifer T. Noisy optical pulses enhance the temporal resolution of pump-probe spectroscopy. PHYSICAL REVIEW LETTERS 2012; 108:098302. [PMID: 22463673 DOI: 10.1103/physrevlett.108.098302] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Indexed: 05/31/2023]
Abstract
Time-resolved measurements of quantum dynamics are based on the availability of controlled events that are shorter than the typical evolution time scale of the processes to be observed. Here we introduce the concept of noise-enhanced pump-probe spectroscopy, allowing the measurement of dynamics significantly shorter than the average pulse duration by exploiting randomly varying, partially coherent light fields consisting of bunched colored noise. These fields are shown to be superior by more than a factor of 10 to frequency-stabilized fields, with important implications for time-resolved experiments at x-ray free-electron lasers and, in general, for measurements at the frontiers of temporal resolution (e.g., attosecond spectroscopy). As an example application, the concept is used to explain the recent experimental observation of vibrational wave-packet motion in D(2)(+) on time scales shorter than the average pulse duration.
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96
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Camus N, Fischer B, Kremer M, Sharma V, Rudenko A, Bergues B, Kübel M, Johnson NG, Kling MF, Pfeifer T, Ullrich J, Moshammer R. Attosecond correlated dynamics of two electrons passing through a transition state. PHYSICAL REVIEW LETTERS 2012; 108:073003. [PMID: 22401200 DOI: 10.1103/physrevlett.108.073003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Indexed: 05/31/2023]
Abstract
The strong-field induced decay of a doubly excited, transient Coulomb complex Ar**→Ar(2+)+2e(-) is explored by tracing correlated two-electron emission in nonsequential double ionization of Ar as a function of the carrier-envelope phase. Using <6 fs pulses, electron emission is essentially confined to one optical cycle. Classical model calculations support that the intermediate Coulomb complex has lost memory of its formation dynamics and allows for a consistent, though model-dependent definition of "emission time," empowering us to trace transition-state two-electron decay dynamics with sub-fs resolution. We find a most likely emission time difference of ∼200±100 as.
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97
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Sansone G, Pfeifer T, Simeonidis K, Kuleff AI. Electron Correlation in Real Time. Chemphyschem 2011; 13:661-80. [DOI: 10.1002/cphc.201100528] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Indexed: 11/11/2022]
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98
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Krishnan SR, Fechner L, Kremer M, Sharma V, Fischer B, Camus N, Jha J, Krishnamurthy M, Pfeifer T, Moshammer R, Ullrich J, Stienkemeier F, Mudrich M, Mikaberidze A, Saalmann U, Rost JM. Dopant-induced ignition of helium nanodroplets in intense few-cycle laser pulses. PHYSICAL REVIEW LETTERS 2011; 107:173402. [PMID: 22107516 DOI: 10.1103/physrevlett.107.173402] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Indexed: 05/31/2023]
Abstract
We demonstrate ultrafast resonant energy absorption of rare-gas doped He nanodroplets from intense few-cycle (~10 fs) laser pulses. We find that less than 10 dopant atoms "ignite" the droplet to generate a nonspherical electronic nanoplasma resulting ultimately in complete ionization and disintegration of all atoms, although the pristine He droplet is transparent for the laser intensities applied. Our calculations at those intensities reveal that the minimal pulse length required for ignition is about 9 fs.
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99
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Holzer M, Gauster M, Pfeifer T, Wadsack C, Fauler G, Stiegler P, Koefeler H, Beubler E, Schuligoi R, Heinemann A, Marsche G. Protein carbamylation renders high-density lipoprotein dysfunctional. Antioxid Redox Signal 2011; 14:2337-46. [PMID: 21235354 PMCID: PMC3380531 DOI: 10.1089/ars.2010.3640] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Carbamylation of proteins through reactive cyanate has been demonstrated to predict an increased cardiovascular risk. Cyanate is formed in vivo by breakdown of urea and at sites of inflammation by the phagocyte protein myeloperoxidase. Because myeloperoxidase (MPO) associates with high-density lipoprotein (HDL) in human atherosclerotic intima, we examined in the present study whether cyanate specifically targets HDL. Mass spectrometry analysis revealed that protein carbamylation is a major posttranslational modification of HDL. The carbamyllysine content of lesion-derived HDL was more than 20-fold higher in comparison with 3-chlorotyrosine levels, a specific oxidation product of MPO. Notably, the carbamyllysine content of lesion-derived HDL was five- to eightfold higher when compared with lesion-derived low-density lipoprotein (LDL) or total lesion protein and increased with lesion severity. The carbamyllysine content of HDL, but not of LDL, correlated with levels of 3-chlorotyrosine, suggesting that MPO mediated carbamylation in the vessel wall. Remarkably, one carbamyllysine residue per HDL-associated apolipoprotein A-I was sufficient to induce cholesterol accumulation and lipid-droplet formation in macrophages through a pathway requiring the HDL-receptor scavenger receptor class B, type I. The present results raise the possibility that HDL carbamylation contributes to foam cell formation in atherosclerotic lesions.
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100
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Kremer M, Hofrichter C, Fischer B, Sharma V, Camus N, Pfeifer T, Moshammer R, Ullrich J. Minimizing dispersive distortions in carrier-envelope phase sweeping with glass wedges. OPTICS LETTERS 2011; 36:1455-1457. [PMID: 21499388 DOI: 10.1364/ol.36.001455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A systematic experimental study is performed to examine the f-2f technique for sweeping the carrier-envelope phase (CEP) of few-cycle laser pulses by changing the amount of positive dispersion in the extracavity beam path. Slightly changing the dispersion not only changes the CEP but affects the entire spectral-phase function. As a result, large discrepancies are found between the true CEP as independently measured with a stereo-above-threshold-ionization spectrometer and the CEP detected by an f-2f interferometer when sweeping the phase with glass wedges. A new CEP-stabilization scheme is proposed and experimentally shown to significantly improve the performance of CEP sweeping.
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