77 research outputs found

    Impulsive control of the atomic dipole response in the time and frequency domain

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    The dipole response of an excited quantum system gives direct insight into the electron dynamics triggered by the incoming light. Spectroscopy techniques such as (attosecond) transient absorption spectroscopy make use of the fact that the dipole response leaves its characteristic fingerprint on the transmitted light. In this work, a general and comprehensive model is introduced, which allows for an analytic description of dipole dynamics triggered and modified by two ultrashort light pulses in both time and frequency domains. Based on this description, a two-dimensional spectral representation of time delay–resolved absorption data is developed. The power of the method to separate different pathways of light–matter interaction, which allows for their individual investigation, is demonstrated experimentally by studying electronic wave packet dynamics in doubly excited helium and inner-valence excited xenon. Furthermore, an in situ technique for characterization of the intense dressing laser pulse that drives (nonlinear) quantum dynamics in time-resolved absorption experiments is derived from the same analytic model and demonstrated experimentally. The possibility to characterize these ultrashort strong-field laser pulses directly within the spectroscopy target enhances the scope of transient absorption spectroscopy as it allows for the precise measurement and control of electron dynamics and increases the comparability between experiment and theory

    PD-L1-Expression in hepatozellulÀren und cholangiozellulÀren Karzinomen

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    Das hepatozellulĂ€re Karzinom (HCC) ist das sechsthĂ€ufigste Karzinom weltweit. Der zweithĂ€ufigste primĂ€re Tumor der Leber ist das cholangiozellulĂ€re Karzinom (CCC). Beide KrebsentitĂ€ten weisen hĂ€ufig keine FrĂŒhsymptome auf, weswegen sie meist erst in einem fortgeschrittenen Stadium entdeckt werden. Dann ist ein palliativer Therapieansatz oftmals die einzige Option, wobei die Therapiemöglichkeiten stark eingeschrĂ€nkt sind. Die Entwicklung neuer Therapiestrategien ist also dringend erforderlich. Ein vielversprechender Ansatz ist die Immuntherapie, wobei ein mögliches therapeutisches Target der Signalweg PD-1/PD-L1 darstellt. Erste Studien dazu lieferten jedoch keine eindeutigen Ergebnisse. Vor diesem Hintergrund war es das Ziel, die PD-L1- Expression mittels Immunhistochemie an einer großen Serie von 550 Gewebeproben, welche in Formalin fixierte und in Paraffin eingebettete HCC- und CCC-PrĂ€parate enthielt, zu untersuchen. FĂŒr die Untersuchungen wurde der Antikörper 73-10 eingesetzt, der sich als besonders sensitiv herausgestellt hatte. Im Ergebnis zeigten sich 51,2% der HCC und 42,3% der CCC PD-L1-positiv, wobei die Expression insgesamt nur schwach ausgeprĂ€gt war. Dabei konnte kein Unterschied zwischen Proben aus China und aus Deutschland und somit zwischen den zugrundeliegenden Ätiologien festgestellt werden. Interessanterweise konnte im tumorumgebenden, noch benignen Gewebe bei beiden TumorentitĂ€ten eine signifikant höhere PD-L1-Expression als in den Tumoren gefunden werden. Außerdem war der PD-L1 in der Umgebung primĂ€rer Lebertumore signifikant stĂ€rker exprimiert als von benignen LeberverĂ€nderungen oder von Metastasen aus anderen Organen. Insgesamt erscheinen HCC und CCC aufgrund der nur geringen PD-L1-Expression fĂŒr eine Anti-PD-1/PD-L1-Therapie nicht generell geeignet. In einigen FĂ€llen könnte es dennoch zu einem Ansprechen auf die Therapie kommen, da es bei primĂ€ren Lebertumoren im umgebenden Gewebe offensichtlich zu einer Hochregulation des PD-L1 kommt

    Determination of absorbed dose to water in a clinical carbon ion beam by means of fluorescent nuclear track detectors, ionization chambers, and water calorimetry

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    Until now, dosimetry of carbon ions with ionization chambers has not reached the same level of accuracy as of high-energy photons. This is mainly caused by the threefold higher uncertainty of the kQ,Q0 -factor of ionization chambers, which is derived by calculations due to a lack of experimental data. The current thesis comprises two major aims with respect to the dosimetry of carbon ion beams: first, the investigation of the potential of fluorescent nuclear track detectors for fluence-based dosimetry and second, the experimental determination of the kQ,Q0 -factor. The direct comparison of fluence- and ionization-based measurements has shown a significant discrepancy of 4.5 %, which re-opened the discussion on the accuracy of calculated kQ,Q0 -factors. Therefore, absorbed dose to water measurements by means of water calorimetry have been performed allowing for the direct calibration of ionization chambers and thus for the experimental determination of kQ,Q0. For the first time it could be shown that the experimental determination of kQ,Q0 for carbon ion beams is achievable with a standard measurement uncertainty of 0.8 %. This corresponds to a threefold reduction of the uncertainty compared to calculated values and therefore enables to significantly decrease the overall uncertainty related to ionization-based dosimetry of clinical carbon ion beams

    Reconstruction and control of a time-dependent two-electron wave packet

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    The concerted motion of two or more bound electrons governs atomic1 and molecular2,3 non-equilibrium processes including chemical reactions, and hence there is much interest in developing a detailed understanding of such electron dynamics in the quantum regime. However, there is no exact solution for the quantumthree-body problem, and as a result even the minimal system of two active electrons and a nucleus is analytically intractable4. This makes experimental measurements of the dynamics of two bound and correlated electrons, as found in the helium atom, an attractive prospect.However, although the motion of single active electrons and holes has been observed with attosecond time resolution5-7, comparable experiments on two-electron motion have so far remained out of reach. Here we showthat a correlated two-electron wave packet can be reconstructed froma 1.2-femtosecondquantumbeatamong low-lying doubly excited states in helium.The beat appears in attosecond transient-absorption spectra5,7-9 measured with unprecedentedly high spectral resolution and in the presence of an intensity-tunable visible laser field.Wetune the coupling10-12 between the two low-lying quantum states by adjusting the visible laser intensity, and use the Fano resonance as a phase-sensitive quantum interferometer13 to achieve coherent control of the two correlated electrons. Given the excellent agreement with large-scalequantum-mechanical calculations for thehelium atom, we anticipate thatmultidimensional spectroscopy experiments of the type we report here will provide benchmark data for testing fundamental few-body quantumdynamics theory in more complex systems. Theymight also provide a route to the site-specificmeasurement and control of metastable electronic transition states that are at the heart of fundamental chemical reactionsWe thank E. Lindroth for calculating the dipole moment (2p2|r|sp2,3+), and also A. Voitkiv, Z.-H. Loh, and R. Moshammer for helpful discussions. We acknowledge financial support by the Max-Planck Research Group Program of the Max-Planck Gesellschaft (MPG) and the European COST Action CM1204 XLIC. L. A. and F. M. acknowledge computer time from the CCC-UAM and Mare Nostrum supercomputer centers and financial support by the European Research Council under the ERC Advanced Grant no. 290853 XCHEM, the Ministerio de EconomĂ­a y Competitividad projects FIS2010-15127, FIS2013-42002-R and ERA-Chemistry PIM2010EEC-00751, and the European grant MC-ITN CORIN

    Deconvolution of complex G protein–coupled receptor signaling in live cells using dynamic mass redistribution measurements

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    Label-free biosensor technology based on dynamic mass redistribution (DMR) of cellular constituents promises to translate GPCR signaling into complex optical 'fingerprints' in real time in living cells. Here we present a strategy to map cellular mechanisms that define label-free responses, and we compare DMR technology with traditional second-messenger assays that are currently the state of the art in GPCR drug discovery. The holistic nature of DMR measurements enabled us to (i) probe GPCR functionality along all four G-protein signaling pathways, something presently beyond reach of most other assay platforms; (ii) dissect complex GPCR signaling patterns even in primary human cells with unprecedented accuracy; (iii) define heterotrimeric G proteins as triggers for the complex optical fingerprints; and (iv) disclose previously undetected features of GPCR behavior. Our results suggest that DMR technology will have a substantial impact on systems biology and systems pharmacology as well as for the discovery of drugs with novel mechanisms

    A geoarchaeological contribution of research

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    INHALTSVERZEICHNIS I ABKÜRZUNGSVERZEICHNIS IV ABBILDUNGSVERZEICHNIS VII TABELLENVERZEICHNIS IX 1\. EINLEITUNG 1.1. MOTIVATION 1.2. DEFINITIONEN 1.3. STAND DER FORSCHUNG 2\. METHODIK 2.1. KARTOGRAPHIE UND GIS 2.1.1. Karten 2.1.2. Satellitendaten 2.1.3. Geographisches Informationssystem (GIS) 2.1.4. Digitales GelĂ€ndemodell 2.1.5. Automatisierte Landschaftsklassifikation 2.2. GELÄNDEARBEITEN 2.2.1. SedimentprofilĂŒberblick 2.2.2. Geomorphologische GelĂ€ndekartierung 2.2.3. Sedimentbeschreibung (Probenentnahmen) 2.3. SEDIMENTANALYTIK 2.3.1. Sedimentaufbereitung 2.3.2. Granulometrie 2.3.3. Kohlenstoffbestimmungen 2.3.4. Elementbestimmungen 2.3.5. Verwitterungsindex mCIA 2.3.6. Bestimmung der Zusammensetzung der mineralogischen Hauptkomponenten 2.4. GEOCHRONOLOGIE 2.4.1. Radiokohlenstoffmethode (AMS-14C) 2.4.2. Infrarot-stimulierte Lumineszenz (IRSL) 3\. GEOGRAPHIE DES SIEBENSTROMLANDES 3.1. Lage und Orographie 3.2. PalĂ€ogeographie 3.3. Klimazonen 3.4. PrĂ€historische Besiedlungsgeschichte 4\. UNTERSUCHUNGSGEBIET 4.1. LAGE DES UNTERSUCHUNGSGEBIETES 4.2. NATURRÄUMLICHE DIFFERENZIERUNG DES UNTERSUCHUNGSGEBIETES 4.2.1. Nördlicher Tien Shan 4.2.2. LösshĂŒgelland 4.2.3. SchwemmfĂ€cher 4.2.4. Schwemmlandebene 4.3. SEDIMENTPROFILE IN DEN LANDSCHAFTSEINHEITEN 5\. ERGEBNISSE 5.1. AUTOMATISIERTE LANDSCHAFTSKLASSIFIKATION 5.2. LANDSCHAFTSEINHEITEN 5.2.1. Nördlicher Tien Shan – Sedimentprofil MB868 5.2.2. LösshĂŒgelland 5.2.2.1. Sedimentprofil MB842 5.2.2.2. Sedimentprofil MB925 5.2.2.3. Sedimentprofil MB926 5.2.3. SchwemmfĂ€cher – Sedimentprofil MB924 5.2.4. Schwemmlandebene 5.2.4.1. Sedimentprofil MB931 5.2.4.2. Sedimentprofil MB921 5.2.4.3. Sedimentprofil MB920 5.3. GEOCHRONOLOGIE 5.3.1. Radiokohlenstoffdatierungen (AMS-14C) 5.3.2. Datierungen nach Infrarot-stimulierter Lumineszenz (IRSL) 6\. DISKUSSION 6.1. AUTOMATISIERTE LANDSCHAFTSKLASSIFIKATION 6.2. SEDIMENTPROFILE 6.2.1. Nördlicher Tien Shan – Sedimentprofil MB868 6.2.2. LösshĂŒgelland 6.2.2.1. Sedimentprofil MB842 6.2.2.2. Sedimentprofil MB925 6.2.2.3. Sedimentprofil MB926 6.2.3. SchwemmfĂ€cher – Sedimentprofil MB924 6.2.4. Schwemmlandebene 6.2.4.1. Sedimentprofil MB931 6.2.4.2. Sedimentprofil MB921 6.2.4.3. Sedimentprofil MB920 6.3. GEOCHRONOLOGIE 6.3.1. Radiokohlenstoffdatierungen (AMS-14C) 6.3.2. Datierungen nach Infrarot-stimulierter Lumineszenz (IRSL) 7\. SCHLUSSFOLGERUNGEN 8\. ZUSAMMENFASSUNG SUMMARY PЕЗмМЕ DANKSAGUNG LITERATURVERZEICHNIS INTERNETQUELLEN ANHANG CURRICULUM VITAEDer Fokus der Dissertation ist auf die geoarchĂ€ologische Landschaftsrekonstruktion in einem Untersuchungsgebiet des kasachischen Siebenstromlandes gerichtet, da Landschafts-rekonstruktionen ein SchlĂŒssel zum VerstĂ€ndnis von Landschaftsentwicklungen sind. Zur Rekonstruktion von Landschaftsentwicklungen und PalĂ€oumweltbedingungen sind eine Vielzahl an Geoarchiven, Proxies und Indizes anwendbar (HOELZMANN et al., 2000; SCHÜTT, 2004; PLUNKETT et al., 2009; SCHWANGHART et al., 2009). Die Landschaft ist in vier Landschaftseinheiten differenzierbar: a) der nördliche Tien Shan, b) das LösshĂŒgelland, c) die SchwemmfĂ€cher und d) die Schwemmlandebene. Die archĂ€ologischen Befunde treten zum einen auf den SchwemmfĂ€chern hervor, wo die (FĂŒrsten-) Kurgane auf SchwemmfĂ€cherterrassen in der SpĂ€tbronzezeit und FrĂŒheisenzeit errichtet worden. Zum anderen liegen die prĂ€historischen Siedlungen im LösshĂŒgelland. Die prĂ€historischen Siedlungen befinden sich sĂŒdlich der GrĂ€berfelder. Die SiedlungsplĂ€tze im LösshĂŒgelland liegen an den Flussufern. Durch ihre Lage am Übergang vom LösshĂŒgelland zum SchwemmfĂ€cher wurde den Saken ein natĂŒrlicher Schutz durch das nördliche Tien Shan geboten (A. GASS, freundliche Mitteilung). Acht Sedimentprofile wurden in den Landschaftseinheiten beprobt. Im Bezug zur prĂ€historischen Besiedlungsgeschichte sind spĂ€tholozĂ€ne LandschaftsverĂ€nderungen festzuhalten. Sie sind am Sedimentprofil MB926 durch Erosionsprozesse belegt (BLÄTTERMANN et al., 2012). Hieraus sind auch mittelholozĂ€ne Erosionsprozesse ohne Besiedlungskontext zu schlussfolgern. Nach PARZINGER (2006) gilt das sĂŒdöstliche Siebenstromland im MittelholozĂ€n als unbesiedelt. Die sakischen Kurgane sind bislang unzerstört auf den SchwemmfĂ€chern sichtbar. Sie sind weder erodiert noch durch Sediment ĂŒberlagert worden. Die Kurgane und der entwickelte Tschernosemboden (max. 4,6 ka) belegen keine LandschaftsverĂ€nderungen (Terrassenniveau 1, MB924). AnknĂŒpfend kann der Mensch die Landschaft mit seinem NaturraumverstĂ€ndnis genutzt haben. Die Förderung von Studien zur Landschaftsrekonstruktion durch die Erfassung naturrĂ€umlicher Parameter, die Analyse des geomorphologischen Formenschatzes und der interdisziplinĂ€ren Verbindung zur ArchĂ€ologie sind der Mehrwert fĂŒr nachhaltige BeitrĂ€ge zur Erforschung des menschlichen Eingriffs auf die Landschaft (Mensch-Umwelt-Beziehungen).Landscape reconstruction plays a key role for understanding landscape developments. This thesis focuses on a geoarchaeological landscape reconstruction in a study area of the Land of Seven Rivers, Kazakhstan, for the prehistoric period of the Saks culture. The natural environment can be subdivided into four landscape units: the northern Tien Shan Mountains, the loess hills, the alluvial fans and an alluvial plain. The Late Bronze and Early Iron Age kurgans of the Sakian culture are located on the alluvial fans. The prehistoric settlements are located southwards of the curgan fields in the loess hills. The landscape of the loess hills has the potential for a natural defense of the settlements (GASS, in press) In accordance with a landscape classification model, the landscape units were traversed by a transect of seven outcrops and one profile. The outcrop-related chronology permits a differentiation into at least four time-slices. The time-slice of the late Holocene (younger than 4 ka) contains chronologically quantifiable landscape changes. They document erosion phases in the loess hills and the alluvial plain. In this time-slice the alluvial fans were already developed. Sediment transports from the loess hills to the alluvial plain were controlled by the alluvial fan characteristics. The loess hills show erosion processes that may be due to both natural and human fac-tors. In the Late Bronze Age and Early Iron Age settlement phases, there are no traces of ei-ther increased or decreased erosion near the loess outcrop MB926. However, human-environment changes cannot be deduced (BLÄTTERMANN et al., 2012). Also PARZINGER (2006) explained that landscape of the Land of Seven Rivers was unsettled before the Andronovo-Fedorovka-culture. The Iron Age kurgans are located on the late Holocene uneroded landscape unit of alluvial fans. The kurgans are today clearly identifiable and show no traces of natural destruction by aeolian or fluvial activity. No sediment accumulations are visible on the alluvial fans. The hypothesis of an uneroded landscape unit during the late Holocene was supported by a chernozem soil horizon with a maximum age of 4.6 ka. Promotion of landscape reconstruction studies by the acquisition of geographical parameters, analysis of geomorphological landforms with their geological backgrounds, and interdisciplinary links with archaeology are the scientific benefits for sustainable studies on the human impact on landscapes (human- environment interactions)

    Systematischer Review zur antiemetischen Prophylaxe bei moderat emetogener Chemotherapie mit besonderer BerĂŒcksichtigung carboplatin- und oxaliplatinhaltiger Regime

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    Übelkeit und Erbrechen stellen, im Rahmen der Chemotherapie, weiterhin relevante Nebenwirkungen dar. Durch 5-HT3-Rezeptorantagonisten, Dexamethason und Neurokinin-1-Rezeptorantagonisten (bzw. Triple-Therapie) konnte Chemotherapie-induziertes Erbrechen und chemotherapie-induzierte Übelkeit reduziert werden. Moderat emetogene Zytostatika (MEC) sind eine heterogene Gruppe mit einem emetogenen Potential zwischen 30-90 %. Im oberen Bereich des Spektrums stehen Carbo- und Oxaliplatin. In Form einer Metaanalyse wurde die aktuelle Studienlage (17 Quellen) analysiert bezĂŒglich des Einsatzes der Triple-Therapie bei der Anwendung von MEC-Regimen, mit als auch ohne Carbo- und Oxaliplatin. Die Daten wurden extrahiert und statistisch ausgewertet. In der Gesamtanalyse und fĂŒr Carboplatin konnte die statische Signifikanz der Triple-Therapie nachgewiesen werden. FĂŒr Oxaliplatin zeigte sich kein statistisch signifikanter Vorteil der Triple-Therapie. Es lĂ€sst sich keine generelle Empfehlung einer Triple-Therapie fĂŒr alle MEC-Regime ableiten aber fĂŒr Carboplatin ist ein positiver Effekt nachzuweisen.Nausea and emesis are still relevant side effects regarding chemotherapy. With the help of 5-HT3-receptor-anatgonists, dexamethasone and neurokinin-1 receptor antagonists (so called triple-therapy) the occurance of chemotherapy-induced nausea and vomiting could be reduced. Moderately emetogenic chemotherapy (MEC) form a heterogenic group, with an emetogenic potential between 90-30 %. Carbo- and oxaliplatin are ranked at the higher end of the spectrum. A meta-analysis of the current data was conducted concerning the use of the triple therapy in MEC with and without carbo- and oxaliplatin. The data were extracted from 17 sources and statistically analyzed. The total analysis and the analysis of carboplatin showed a statistically significant benefit of the triple-therapy. This could not be shown for the oxaliplatin group. A general recommendation to use the triple-therapy in MEC-regimens cannot be made but a positive effect in carboplatin-based regimens was found

    A two-layered wavelet-based algorithm for efficient lossless and lossy image compression

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    In this paper, we propose a wavelet-based image-coding scheme allowing lossless and lossy compression, simultaneously. Our two-layered approach utilizes the best of two worlds: it uses a highly performing wavelet-based or wavelet packet-based coding technique for lossy compression in the low bit range as a first stage. For the second (optional) stage, we extend the concept of reversible integer wavelet transforms to the more flexible class of adaptive reversible integer wavelet packet transforms which are based on the generation of a whole library of bases, from which the best representation for a given residue between the reconstructed lossy compressed image and the original image is chosen using a fast-search algorithm. We present experimental results demonstrating that our compression algorithm yields a rate-distortion performance similar or superior to the best currently published pure lossy still image-coding methods. At the same time, the lossless compression perf ormance of our two-layered scheme is comparable to that of state-of-the-art pure lossless image-coding schemes. Compared to other combined lossy/lossless coding schemes such as the emerging JPEG-2000 still image-coding standard PSNR improvements up to 3 dB are achieved for a set of standard test images
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