TY - JOUR A1 - Röhrich, Christian Rene A1 - Ngwa, Che Julius A1 - Wiesner, Jochen A1 - Schmidtberg, Henrike A1 - Degenkolb, Thomas A1 - Kollewe, Christian A1 - Fischer, Rainer A1 - Pradel, Gabriele A1 - Vilcinskas, Andreas T1 - Harmonine, a defence compound from the harlequin ladybird, inhibits mycobacterial growth and demonstrates multi-stage antimalarial activity JF - Biology Letters N2 - The harlequin ladybird beetle Harmonia axyridis has been introduced in many countries as a biological control agent, but has become an invasive species threatening the biodiversity of native ladybirds. Its invasive success has been attributed to its vigorous resistance against diverse pathogens. This study demonstrates that harmonine ((17R,9Z)-1,17-diaminooctadec-9-ene), which is present in H. axyridis haemolymph, displays broad-spectrum antimicrobial activity that includes human pathogens. Antibacterial activity is most pronounced against fast-growing mycobacteria and Mycobacterium tuberculosis, and the growth of both chloroquine-sensitive and -resistant Plasmodium falciparum strains is inhibited. Harmonine displays gametocytocidal activity, and inhibits the exflagellation of microgametocytes and zygote formation. In an Anopheles stephensi mosquito feeding model, harmonine displays transmission-blocking activity. KW - insect immunity KW - antimicrobial activity KW - harmonine KW - harmonia axyridis Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127079 VL - 8 ER - TY - JOUR A1 - Aeschlimann, Martin A1 - Bauer, Michael A1 - Bayer, Daniela A1 - Brixner, Tobias A1 - Cunovic, Stefan A1 - Fischer, Alexander A1 - Melchior, Pascal A1 - Pfeiffer, Walter A1 - Rohmer, Martin A1 - Schneider, Christian A1 - Strüber, Christian A1 - Tuchscherer, Philip A1 - Voronine, Dimitri V. T1 - Optimal open-loop near-field control of plasmonic nanostructures N2 - Optimal open-loop control, i.e. the application of an analytically derived control rule, is demonstrated for nanooptical excitations using polarization-shaped laser pulses. Optimal spatial near-field localization in gold nanoprisms and excitation switching is realized by applying a shift to the relative phase of the two polarization components. The achieved near-field switching confirms theoretical predictions, proves the applicability of predefined control rules in nanooptical light–matter interaction and reveals local mode interference to be an important control mechanism. KW - Chemie Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-75256 ER - TY - JOUR A1 - Pietro-Garcia, Christian A1 - Hartmann, Oliver A1 - Reissland, Michaela A1 - Fischer, Thomas A1 - Maier, Carina R. A1 - Rosenfeldt, Mathias A1 - Schülein-Völk, Christina A1 - Klann, Kevin A1 - Kalb, Reinhard A1 - Dikic, Ivan A1 - Münch, Christian A1 - Diefenbacher, Markus E. T1 - Inhibition of USP28 overcomes Cisplatin-resistance of squamous tumors by suppression of the Fanconi anemia pathway JF - Cell Death and Differentiation N2 - Squamous cell carcinomas (SCC) frequently have an exceptionally high mutational burden. As consequence, they rapidly develop resistance to platinum-based chemotherapy and overall survival is limited. Novel therapeutic strategies are therefore urgently required. SCC express ∆Np63, which regulates the Fanconi Anemia (FA) DNA-damage response in cancer cells, thereby contributing to chemotherapy-resistance. Here we report that the deubiquitylase USP28 is recruited to sites of DNA damage in cisplatin-treated cells. ATR phosphorylates USP28 and increases its enzymatic activity. This phosphorylation event is required to positively regulate the DNA damage repair in SCC by stabilizing ∆Np63. Knock-down or inhibition of USP28 by a specific inhibitor weakens the ability of SCC to cope with DNA damage during platin-based chemotherapy. Hence, our study presents a novel mechanism by which ∆Np63 expressing SCC can be targeted to overcome chemotherapy resistance. Limited treatment options and low response rates to chemotherapy are particularly common in patients with squamous cancer. The SCC specific transcription factor ∆Np63 enhances the expression of Fanconi Anemia genes, thereby contributing to recombinational DNA repair and Cisplatin resistance. Targeting the USP28-∆Np63 axis in SCC tones down this DNA damage response pathways, thereby sensitizing SCC cells to cisplatin treatment. KW - USP28 KW - Cisplatin KW - squamous tumors Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-273014 SN - 1476-5403 VL - 29 IS - 3 ER - TY - INPR A1 - Hoche, Joscha A1 - Schmitt, Hans-Christian A1 - Humeniuk, Alexander A1 - Fischer, Ingo A1 - Mitrić, Roland A1 - Röhr, Merle I. S. T1 - The mechanism of excimer formation: an experimental and theoretical study on the pyrene dimer T2 - Physical Chemistry Chemical Physics N2 - The understanding of excimer formation in organic materials is of fundamental importance, since excimers profoundly influence their functional performance in applications such as light-harvesting, photovoltaics or organic electronics. We present a joint experimental and theoretical study of the ultrafast dynamics of excimer formation in the pyrene dimer in a supersonic jet, which is the archetype of an excimer forming system. We perform simulations of the nonadiabatic photodynamics in the frame of TDDFT that reveal two distinct excimer formation pathways in the gas-phase dimer. The first pathway involves local excited state relaxation close to the initial Franck–Condon geometry that is characterized by a strong excitation of the stacking coordinate exhibiting damped oscillations with a period of 350 fs that persist for several picoseconds. The second excimer forming pathway involves large amplitude oscillations along the parallel shift coordinate with a period of ≈900 fs that after intramolecular vibrational energy redistribution leads to the formation of a perfectly stacked dimer. The electronic relaxation within the excitonic manifold is mediated by the presence of intermolecular conical intersections formed between fully delocalized excitonic states. Such conical intersections may generally arise in stacked π-conjugated aggregates due to the interplay between the long-range and short-range electronic coupling. The simulations are supported by picosecond photoionization experiments in a supersonic jet that provide a time-constant for the excimer formation of around 6–7 ps, in good agreement with theory. Finally, in order to explore how the crystal environment influences the excimer formation dynamics we perform large scale QM/MM nonadiabatic dynamics simulations on a pyrene crystal in the framework of the long-range corrected tight-binding TDDFT. In contrast to the isolated dimer, the excimer formation in the crystal follows a single reaction pathway in which the initially excited parallel slip motion is strongly damped by the interaction with the surrounding molecules leading to the slow excimer stabilization on a picosecond time scale. KW - exciton dynamics KW - pyrene dimer Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159656 UR - http://dx.doi.org/10.1039/C7CP03990E N1 - Submitted version ER - TY - JOUR A1 - Kim, Seonghoon A1 - Zhang, Bo A1 - Wang, Zhaorong A1 - Fischer, Julian A1 - Brodbeck, Sebastian A1 - Kamp, Martin A1 - Schneider, Christian A1 - Höfling, Sven A1 - Deng, Hui T1 - Coherent Polariton Laser JF - Physical Review X N2 - The semiconductor polariton laser promises a new source of coherent light, which, compared to conventional semiconductor photon lasers, has input-energy threshold orders of magnitude lower. However, intensity stability, a defining feature of a coherent state, has remained poor. Intensity noise many times the shot noise of a coherent state has persisted, attributed to multiple mechanisms that are difficult to separate in conventional polariton systems. The large intensity noise, in turn, limits the phase coherence. Thus, the capability of the polariton laser as a source of coherence light is limited. Here, we demonstrate a polariton laser with shot-noise-limited intensity stability, as expected from a fully coherent state. This stability is achieved by using an optical cavity with high mode selectivity to enforce single-mode lasing, suppress condensate depletion, and establish gain saturation. Moreover, the absence of spurious intensity fluctuations enables the measurement of a transition from exponential to Gaussian decay of the phase coherence of the polariton laser. It suggests large self-interaction energies in the polariton condensate, exceeding the laser bandwidth. Such strong interactions are unique to matter-wave lasers and important for nonlinear polariton devices. The results will guide future development of polariton lasers and nonlinear polariton devices. KW - polariton laser KW - condensed matter physics KW - photonics KW - quantum physics KW - coherent light Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166597 VL - 6 IS - 011026 ER - TY - JOUR A1 - Hoche, Joscha A1 - Schmitt, Hans-Christian A1 - Humeniuk, Alexander A1 - Fischer, Ingo A1 - Mitrić, Roland A1 - Röhr, Merle I. S. T1 - The mechanism of excimer formation: an experimental and theoretical study on the pyrene dimer JF - Physical Chemistry Chemical Physics N2 - The understanding of excimer formation in organic materials is of fundamental importance, since excimers profoundly influence their functional performance in applications such as light-harvesting, photovoltaics or organic electronics. We present a joint experimental and theoretical study of the ultrafast dynamics of excimer formation in the pyrene dimer in a supersonic jet, which is the archetype of an excimer forming system. We perform simulations of the nonadiabatic photodynamics in the frame of TDDFT that reveal two distinct excimer formation pathways in the gas-phase dimer. The first pathway involves local excited state relaxation close to the initial Franck–Condon geometry that is characterized by a strong excitation of the stacking coordinate exhibiting damped oscillations with a period of 350 fs that persist for several picoseconds. The second excimer forming pathway involves large amplitude oscillations along the parallel shift coordinate with a period of ≈900 fs that after intramolecular vibrational energy redistribution leads to the formation of a perfectly stacked dimer. The electronic relaxation within the excitonic manifold is mediated by the presence of intermolecular conical intersections formed between fully delocalized excitonic states. Such conical intersections may generally arise in stacked π-conjugated aggregates due to the interplay between the long-range and short-range electronic coupling. The simulations are supported by picosecond photoionization experiments in a supersonic jet that provide a time-constant for the excimer formation of around 6–7 ps, in good agreement with theory. Finally, in order to explore how the crystal environment influences the excimer formation dynamics we perform large scale QM/MM nonadiabatic dynamics simulations on a pyrene crystal in the framework of the long-range corrected tight-binding TDDFT. In contrast to the isolated dimer, the excimer formation in the crystal follows a single reaction pathway in which the initially excited parallel slip motion is strongly damped by the interaction with the surrounding molecules leading to the slow excimer stabilization on a picosecond time scale. KW - exciton dynamics KW - pyrene dimer Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159514 UR - http://dx.doi.org/10.1039/C7CP03990E N1 - Accepted version VL - 19 IS - 36 ER - TY - JOUR A1 - Amthor, Matthias A1 - Weißenseel, Sebastian A1 - Fischer, Julian A1 - Kamp, Martin A1 - Schneider, Christian A1 - Höfling, Sven T1 - Electro-optical switching between polariton and cavity lasing in an InGaAs quantum well microcavity N2 - We report on the condensation of microcavity exciton polaritons under optical excitation in a microcavity with four embedded InGaAs quantum wells. The polariton laser is characterized by a distinct nonlinearity in the input-output-characteristics, which is accompanied by a drop of the emission linewidth indicating temporal coherence and a characteristic persisting emission blueshift with increased particle density. The temporal coherence of the device at threshold is underlined by a characteristic drop of the second order coherence function to a value close to 1. Furthermore an external electric field is used to switch between polariton regime, polariton condensate and photon lasing. KW - Quantum-well, -wire and -dot devices KW - Scattering KW - stimulated KW - Resonators KW - Microcavity devices Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-111130 ER - TY - JOUR A1 - Ladwig, Karl-Heinz A1 - Lederbogen, Florian A1 - Albus, Christian A1 - Angermann, Christiane A1 - Borggrefe, Martin A1 - Fischer, Denise A1 - Fritzsche, Kurt A1 - Haass, Markus A1 - Jordan, Jochen A1 - Jünger, Jana A1 - Kindermann, Ingrid A1 - Köllner, Volker A1 - Kuhn, Bernhard A1 - Scherer, Martin A1 - Seyfarth, Melchior A1 - Völler, Heinz A1 - Waller, Christiane A1 - Herrmann-Lingen, Christoph T1 - Position paper on the importance of psychosocial factors in cardiology: Update 2013 T1 - Positionspapier zur Bedeutung psychosozialer Faktoren in der Kardiologie: Update 2013 JF - GMS German Medical Science N2 - Background: The rapid progress of psychosomatic research in cardiology and also the increasing impact of psychosocial issues in the clinical daily routine have prompted the Clinical Commission of the German Heart Society (DGK) to agree to an update of the first state of the art paper on this issue which was originally released in 2008. Methods: The circle of experts was increased, general aspects were implemented and the state of the art was updated. Particular emphasis was dedicated to coronary heart diseases (CHD), heart rhythm diseases and heart failure because to date the evidence-based clinical knowledge is most advanced in these particular areas. Differences between men and women and over the life span were considered in the recommendations as were influences of cognitive capability and the interactive and synergistic impact of classical somatic risk factors on the affective comorbidity in heart disease patients. Results: A IA recommendation (recommendation grade I and evidence grade A) was given for the need to consider psychosocial risk factors in the estimation of coronary risks as etiological and prognostic risk factors. Furthermore, for the recommendation to routinely integrate psychosocial patient management into the care of heart surgery patients because in these patients, comorbid affective disorders (e.g. depression, anxiety and post-traumatic stress disorder) are highly prevalent and often have a malignant prognosis. A IB recommendation was given for the treatment of psychosocial risk factors aiming to prevent the onset of CHD, particularly if the psychosocial risk factor is harmful in itself (e.g. depression) or constrains the treatment of the somatic risk factors. Patients with acute and chronic CHD should be offered anti-depressive medication if these patients suffer from medium to severe states of depression and in this case medication with selective reuptake inhibitors should be given. In the long-term course of treatment with implanted cardioverter defibrillators (ICDs) a subjective health technology assessment is warranted. In particular, the likelihood of affective comorbidities and the onset of psychological crises should be carefully considered. Conclusions: The present state of the art paper presents an update of current empirical evidence in psychocardiology. The paper provides evidence-based recommendations for the integration of psychosocial factors into cardiological practice and highlights areas of high priority. The evidence for estimating the efficiency for psychotherapeutic and psychopharmacological interventions has increased substantially since the first release of the policy document but is, however, still weak. There remains an urgent need to establish curricula for physician competence in psychodiagnosis, communication and referral to ensure that current psychocardiac knowledge is translated into the daily routine. N2 - Hintergrund: Die rasche Weiterentwicklung der psychokardiologischen Forschung, aber auch die wachsende Verankerung psychosozialer Fragestellungen im klinischen Alltag haben die Klinische Kommission der DGK bewogen, einer Aktualisierung und Weiterentwicklung des 2008 erstmals publizierten Positionspapiers zur Bedeutung psychosozialer Faktoren in der Kardiologie zuzustimmen. Methoden: Der Kreis der Autoren wurde vergrößert, allgemeine Aspekte eingefügt und das Wissen in allen Abschnitten auf den heutigen Stand gebracht. Schwerpunkte der Empfehlungen sind die koronare Herzerkrankung, Herzrhythmusstörungen und die Herzinsuffizienz, da hier der Stand der empirischen Evidenz und des klinisches Wissens zu psychosozialen Fragestellungen am weitesten entwickelt ist. Berücksichtigt wurden bei den Empfehlungen Besonderheiten von Frauen und Männern, Unterschiede bzgl. der Lebensspanne, Einflüsse auf die kognitive Leistungsfähigkeit und die interaktive synergistische Bedeutung klassischer Risikofaktoren bei affektiver Komorbidität. Ergebnisse: Eine I-A-Empfehlung (Empfehlungsgrad I, Evidenzgrad A) wurde vergeben für die Aufforderung, psychosoziale Risikofaktoren bei der Einschätzung des KHK-Risikos zu berücksichtigen, die als unabhängige ätiologische und prognostische Risikofaktoren für das Auftreten der koronaren Herzerkrankung (KHK) und für Komplikationen im Behandlungsverlauf der KHK bedeutsam sind. Ferner für die Empfehlung, Patienten mit Herzoperationen von einem interdisziplinären Team zu betreuten, in dem die Möglichkeit besteht, auf psychosoziale Aspekte einzugehen, da bei diesen Patienten komorbide psychische Störungen wie Depressivität, Angst und posttraumatische Belastungsstörung häufig und prognostisch ungünstig sind. Eine I-B-Empfehlung wurde vergeben für die Behandlung psychosozialer Risikofaktoren mit dem Ziel einer Primärprävention der KHK, wenn das Risikomerkmal an sich Krankheitswert hat (z. B. Depression) oder die Behandlung klassischer Risikofaktoren erschwert ist. Eine antidepressive Pharmakotherapie soll Patienten nach akutem Koronarsyndrom sowie in der Phase der chronischen KHK angeboten werden, die an einer mindestens mittelschweren rezidivierenden depressiven Störung leiden. Dabei sollen vorzugsweise Substanzen aus der Gruppe der selektiven Serotoninwiederaufnahmehemmer (SSRI) zum Einsatz kommen. Bei der langfristigen ärztlichen Begleitung von ICD-Patienten sollen die psychosozialen Folgen der ICD-Technologie beachtet und insbesondere relevante Affektstörungen sowie Krisen bei ICD-Patienten erkannt und fachgerecht behandelt werden. Schlussfolgerungen: Das Positionspapier formuliert konkrete Anwendungsfelder mit hoher Priorität für die Einbeziehung psychosozialer Faktoren in die kardiologische Praxis, die eine leitlinienkonforme Evidenz aufweisen. Trotz deutlicher Fortschritte seit der Erstveröffentlichung des Positionspapiers existieren weiterhin Forschungsdefizite für die Bewertung der Wirksamkeit psychotherapeutischer und psychopharmakologischer Konzepte bei kardialen Patienten. Curricula für die Vermittlung von (psycho-)diagnostischer, kommunikativer und differenzialdiagnostischer Kompetenz müssen rasch entwickelt werden, um eine Transmission des aktuellen Wissensstands in die Alltagspraxis zu ermöglichen. KW - depression KW - anxiety KW - post-traumatic stress disorder KW - psychotherapy KW - psychopharmacology KW - Depression KW - Psychopharmakologie KW - Psychotherapie KW - posttraumatische Belastungsstörung KW - Angst Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-121196 VL - 12 ER - TY - JOUR A1 - Dorsch, Oliver A1 - Krieter, Detlef H. A1 - Lemke, Horst-Dieter A1 - Fischer, Stefan A1 - Melzer, Nima A1 - Sieder, Christian A1 - Bramlage, Peter A1 - Harenberg, Job T1 - A multi-center, prospective, open-label, 8-week study of certoparin for anticoagulation during maintenance hemodialysis – the membrane study JF - BMC Nephrology N2 - Background Adequate anticoagulation is prerequisite for effective hemodialysis to prevent clotting in the extracorporeal circuit. We aimed providing first data on the efficacy and safety of the low-molecular-weight heparin certoparin in this setting. Methods Multicenter, open-label, 8-week trial. Patients received a single dose of 3,000 IU certoparin i.v. with additional titration steps of 600 IU and/or continuous infusion if necessary. Results 120 patients were screened, 109 enrolled (median age 71; range 26–90 years) and 106 available for efficacy analyses. The percentage of unsatisfactory dialysis results at 8 weeks due to clotting or bleeding, was 1.9% (n = 2/106; 95% confidence interval [CI] 0.23–6.65%); no major bleeding. 1.9% had moderate/severe clotting in the lines/bubble catcher and 2.8% in the dialyser at week 8. 15.7 ± 14.3% of the dialysis filters’ visual surface area was showing redness. In subgroups of patients receiving median doses of 3000 ± 0, 3000 (2400–6000) and 4200 (3000–6600) IU, plasma aXa levels at baseline, 4 and 8 weeks were 0.24 [95%CI 0.21–0.27], 0.33 [0.27–0.40] and 0.38 [0.33–0.45] aXa IU/ml at 2 h. \(C_{48h}\) was 0.01 [0.01–0.02] aXa IU at all visits. At baseline and 4 weeks \(AUC_{0-48h}\) was 2.66 [2.19–3.24] and 3.66 [3.00–4.45] aXa IU*h/ml. In 3.0% of dialyses (n = 83/2724) prolonged fistula compression times were documented. Eight patients (7.34%) had at least one episode of minor bleeding. 4) 85.3% of patients had any adverse event, 9.2% were serious without suspected drug relation; and in 32 patients a drug-relation was suspected. Conclusions Certoparin appears effective and safe for anticoagulation in patients undergoing maintenance hemodialysis. KW - hemodialysis Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-124052 VL - 13 IS - 50 ER - TY - JOUR A1 - Winkler, Karol A1 - Fischer, Julian A1 - Schade, Anne A1 - Amthor, Matthias A1 - Dall, Robert A1 - Geßler, Jonas A1 - Emmerling, Monika A1 - Ostrovskaya, Elena A. A1 - Kamp, Martin A1 - Schneider, Christian A1 - Höfling, Sven T1 - A polariton condensate in a photonic crystal potential landscape JF - New Journal of Physics N2 - The possibility of investigating macroscopic coherent quantum states in polariton condensates and of engineering polariton landscapes in semiconductors has triggered interest in using polaritonic systems to simulate complex many-body phenomena. However, advanced experiments require superior trapping techniques that allow for the engineering of periodic and arbitrary potentials with strong on-site localization, clean condensate formation, and nearest-neighbor coupling. Here we establish a technology that meets these demands and enables strong, potentially tunable trapping without affecting the favorable polariton characteristics. The traps are based on a locally elongated microcavity which can be formed by standard lithography. We observe polariton condensation with non-resonant pumping in single traps and photonic crystal square lattice arrays. In the latter structures, we observe pronounced energy bands, complete band gaps, and spontaneous condensation at the M-point of the Brillouin zone. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125050 VL - 17 ER -