TY - JOUR A1 - Süß, Jasmin A1 - Wehner, Johannes G. A1 - Dostál, Jakub A1 - Engel, Volker A1 - Brixner, Tobias T1 - Mapping of exciton-exciton annihilation in a molecular dimer via fifth-order femtosecond two-dimensional spectroscopy JF - Journal of Physical Chemistry Letters N2 - We present a theoretical study on exciton–exciton annihilation (EEA) in a molecular dimer. This process is monitored using a fifth-order coherent two-dimensional (2D) spectroscopy as was recently proposed by Dostál et al. [Nat. Commun. 9, 2466 (2018)]. Using an electronic three-level system for each monomer, we analyze the different paths which contribute to the 2D spectrum. The spectrum is determined by two entangled relaxation processes, namely, the EEA and the direct relaxation of higher lying excited states. It is shown that the change of the spectrum as a function of a pulse delay can be linked directly to the presence of the EEA process. KW - exciton-exciton KW - Exziton KW - Spektroskopie KW - EEA KW - 2Dimensionale Spektroskopie KW - exciton Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-178420 UR - https://aip.scitation.org/doi/full/10.1063/1.5086151 N1 - This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in J. Süß et al., J. Chem. Phys. 150, 104304 (2019); https://doi.org/10.1063/1.5086151 and may be found at https://doi.org/10.1063/1.5086151. VL - 150 IS - 10 ER - TY - INPR A1 - Süß, Jasmin A1 - Wehner, Johannes G. A1 - Dostál, Jakub A1 - Engel, Volker A1 - Brixner, Tobias T1 - Mapping of exciton-exciton annihilation in a molecular dimer via fifth-order femtosecond two-dimensional spectroscopy T2 - Journal of Physical Chemistry Letters N2 - We present a theoretical study on exciton–exciton annihilation (EEA) in a molecular dimer. This process is monitored using a fifth-order coherent two-dimensional (2D) spectroscopy as was recently proposed by Dostál et al. [Nat. Commun. 9, 2466 (2018)]. Using an electronic three-level system for each monomer, we analyze the different paths which contribute to the 2D spectrum. The spectrum is determined by two entangled relaxation processes, namely, the EEA and the direct relaxation of higher lying excited states. It is shown that the change of the spectrum as a function of a pulse delay can be linked directly to the presence of the EEA process. KW - Exziton KW - Spektroskopie KW - Exciton KW - 2Dimensionale Spektroskopie KW - EEA KW - exciton-exciton Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-178482 UR - https://aip.scitation.org/doi/full/10.1063/1.5086151 N1 - This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in J. Süß et al.,J. Chem. Phys. 150, 104304 (2019); https://doi.org/10.1063/1.5086151 and may be found at https://doi.org/10.1063/1.5086151 ER - TY - JOUR A1 - Brüning, Christoph A1 - Wehner, Johannes A1 - Hausner, Julian A1 - Wenzel, Michael A1 - Engel, Volker T1 - Exciton dynamics in perturbed vibronic molecular aggregates JF - Structural Dynamics N2 - A site specific perturbation of a photo-excited molecular aggregate can lead to a localization of excitonic energy. We investigate this localization dynamics for laser-prepared excited states. Changing the parameters of the electric field significantly influences the exciton localization which offers the possibility for a selective control of this process. This is demonstrated for aggregates possessing a single vibrational degree of freedom per monomer unit. It is shown that the effects identified for the molecular dimer can be generalized to larger aggregates with a high density of vibronic states. KW - absorption spectra KW - excited states KW - polymers KW - excitons KW - wave functions Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126085 VL - 3 ER - TY - JOUR A1 - Engel, Volker A1 - Albert, Julian A1 - Schubert, Alexander T1 - Two-dimensional vibronic spectroscopy of molecular predissociation JF - New Journal of Physics N2 - We calculate two-dimensional (2D) spectra reflecting the time-dependent electronic predissociation of a diatomic molecule. The laser-excited electronic state is coupled non-adiabatically to a fragment channel, leading to the decay of the prepared quasi-bound states. This decay can be monitored by the three-pulse configuration employed in optical 2D spectroscopy. It is shown that in this way it is possible to state-selectively characterize the time-dependent population of resonance states with different lifetimes. A model of the NaI molecule serves as a numerical example. KW - computational physics KW - atomic physics KW - molecular physics Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-96199 ER - TY - JOUR A1 - Guth, Sabine A1 - Hüser, Stephanie A1 - Roth, Angelika A1 - Degen, Gisela A1 - Diel, Patrick A1 - Edlund, Karolina A1 - Eisenbrand, Gerhard A1 - Engel, Karl-Heinz A1 - Epe, Bernd A1 - Grune, Tilman A1 - Heinz, Volker A1 - Henle, Thomas A1 - Humpf, Hans-Ulrich A1 - Jäger, Henry A1 - Joost, Hans-Georg A1 - Kulling, Sabine E. A1 - Lampen, Alfonso A1 - Mally, Angela A1 - Marchan, Rosemarie A1 - Marko, Doris A1 - Mühle, Eva A1 - Nitsche, Michael A. A1 - Röhrdanz, Elke A1 - Stadler, Richard A1 - van Thriel, Christoph A1 - Vieths, Stefan A1 - Vogel, Rudi F. A1 - Wascher, Edmund A1 - Watzl, Carsten A1 - Nöthlings, Ute A1 - Hengstler, Jan G. T1 - Contribution to the ongoing discussion on fluoride toxicity JF - Archives of Toxicology N2 - Since the addition of fluoride to drinking water in the 1940s, there have been frequent and sometimes heated discussions regarding its benefits and risks. In a recently published review, we addressed the question if current exposure levels in Europe represent a risk to human health. This review was discussed in an editorial asking why we did not calculate benchmark doses (BMD) of fluoride neurotoxicity for humans. Here, we address the question, why it is problematic to calculate BMDs based on the currently available data. Briefly, the conclusions of the available studies are not homogeneous, reporting negative as well as positive results; moreover, the positive studies lack control of confounding factors such as the influence of well-known neurotoxicants. We also discuss the limitations of several further epidemiological studies that did not meet the inclusion criteria of our review. Finally, it is important to not only focus on epidemiological studies. Rather, risk analysis should consider all available data, including epidemiological, animal, as well as in vitro studies. Despite remaining uncertainties, the totality of evidence does not support the notion that fluoride should be considered a human developmental neurotoxicant at current exposure levels in European countries. KW - pharmacology/toxicology KW - occupational medicine/industrial medicine KW - environmental health KW - biomedicine, general Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-307161 SN - 0340-5761 SN - 1432-0738 VL - 95 IS - 7 ER - TY - JOUR A1 - Schürger, Peter A1 - Engel, Volker T1 - Differential Shannon entropies characterizing electron–nuclear dynamics and correlation: momentum-space versus coordinate-space wave packet motion JF - Entropy N2 - We calculate differential Shannon entropies derived from time-dependent coordinate-space and momentum-space probability densities. This is performed for a prototype system of a coupled electron–nuclear motion. Two situations are considered, where one is a Born–Oppenheimer adiabatic dynamics, and the other is a diabatic motion involving strong non-adiabatic transitions. The information about coordinate- and momentum-space dynamics derived from the total and single-particle entropies is discussed and interpreted with the help of analytical models. From the entropies, we derive mutual information, which is a measure for the electron–nuclear correlation. In the adiabatic case, it is found that such correlations are manifested differently in coordinate- and momentum space. For the diabatic dynamics, we show that it is possible to decompose the entropies into state-specific contributions. KW - differential Shannon entropy KW - correlation KW - electron–nuclear dynamics Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-362670 SN - 1099-4300 VL - 25 IS - 7 ER - TY - JOUR A1 - Schürger, Peter A1 - Engel, Volker T1 - On the relation between nodal structures in quantum wave functions and particle correlation JF - AIP Advances N2 - We study the influence of nodal structures in two-dimensional quantum mechanical densities on wave packet entanglement. This is motivated by our recent study [Entropy, 25, 970 (2023)], which showed that the mutual information derived from the momentum-space probability density of a coupled two-particle system exhibits an unusual time dependence, which is not encountered if the position-space density is employed in the calculation. In studying a model density, here, we identify cases where the mutual information increases with the number of nodes in the wave function and approaches a finite value, whereas in this limit, the linear correlation vanishes. The results of the analytical model are then applied to interpret the correlation measures for coupled electron-nuclear dynamics, which are treated by numerically solving the time-dependent Schrödinger equation. KW - nodal structures KW - information theory entropy KW - particle correlations KW - time-dependent Schrodinger equation KW - covariance and correlation KW - quantum wave functions KW - Schroedinger equation Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-350361 VL - 13 IS - 12 ER - TY - JOUR A1 - Schmidt, Paul A1 - Fantuzzi, Felipe A1 - Klopf, Jonas A1 - Schröder, Niklas B. A1 - Dewhurst, Rian D. A1 - Braunschweig, Holger A1 - Engel, Volker A1 - Engels, Bernd T1 - Twisting versus delocalization in CAAC- and NHC-stabilized boron-based biradicals: the roles of sterics and electronics JF - Chemistry - A European Journal N2 - Twisted boron-based biradicals featuring unsaturated C\(_2\)R\(_2\) (R=Et, Me) bridges and stabilization by cyclic (alkyl)(amino)carbenes (CAACs) were recently prepared. These species show remarkable geometrical and electronic differences with respect to their unbridged counterparts. Herein, a thorough computational investigation on the origin of their distinct electrostructural properties is performed. It is shown that steric effects are mostly responsible for the preference for twisted over planar structures. The ground-state multiplicity of the twisted structure is modulated by the σ framework of the bridge, and different R groups lead to distinct multiplicities. In line with the experimental data, a planar structure driven by delocalization effects is observed as global minimum for R=H. The synthetic elusiveness of C\(_2\)R\(_2\)-bridged systems featuring N-heterocyclic carbenes (NHCs) was also investigated. These results could contribute to the engineering of novel main group biradicals. KW - chemistry KW - radicals KW - ab initio calculations KW - boron KW - carbene ligands KW - density functional calculations Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256636 VL - 27 IS - 16 ER - TY - JOUR A1 - Ferreira, Manuel A. A1 - Gamazon, Eric R. A1 - Al-Ejeh, Fares A1 - Aittomäki, Kristiina A1 - Andrulis, Irene L. A1 - Anton-Culver, Hoda A1 - Arason, Adalgeir A1 - Arndt, Volker A1 - Aronson, Kristan J. A1 - Arun, Banu K. A1 - Asseryanis, Ella A1 - Azzollini, Jacopo A1 - Balmaña, Judith A1 - Barnes, Daniel R. A1 - Barrowdale, Daniel A1 - Beckmann, Matthias W. A1 - Behrens, Sabine A1 - Benitez, Javier A1 - Bermisheva, Marina A1 - Bialkowska, Katarzyna A1 - Blomqvist, Carl A1 - Bogdanova, Natalia V. A1 - Bojesen, Stig E. A1 - Bolla, Manjeet K. A1 - Borg, Ake A1 - Brauch, Hiltrud A1 - Brenner, Hermann A1 - Broeks, Annegien A1 - Burwinkel, Barbara A1 - Caldés, Trinidad A1 - Caligo, Maria A. A1 - Campa, Daniele A1 - Campbell, Ian A1 - Canzian, Federico A1 - Carter, Jonathan A1 - Carter, Brian D. A1 - Castelao, Jose E. A1 - Chang-Claude, Jenny A1 - Chanock, Stephen J. A1 - Christiansen, Hans A1 - Chung, Wendy K. A1 - Claes, Kathleen B. M. A1 - Clarke, Christine L. A1 - Couch, Fergus J. A1 - Cox, Angela A1 - Cross, Simon S. A1 - Czene, Kamila A1 - Daly, Mary B. A1 - de la Hoya, Miguel A1 - Dennis, Joe A1 - Devilee, Peter A1 - Diez, Orland A1 - Dörk, Thilo A1 - Dunning, Alison M. A1 - Dwek, Miriam A1 - Eccles, Diana M. A1 - Ejlertsen, Bent A1 - Ellberg, Carolina A1 - Engel, Christoph A1 - Eriksson, Mikael A1 - Fasching, Peter A. A1 - Fletcher, Olivia A1 - Flyger, Henrik A1 - Friedman, Eitan A1 - Frost, Debra A1 - Gabrielson, Marike A1 - Gago-Dominguez, Manuela A1 - Ganz, Patricia A. A1 - Gapstur, Susan M. A1 - Garber, Judy A1 - García-Closas, Montserrat A1 - García-Sáenz, José A. A1 - Gaudet, Mia M. A1 - Giles, Graham G. A1 - Glendon, Gord A1 - Godwin, Andrew K. A1 - Goldberg, Mark S. A1 - Goldgar, David E. A1 - González-Neira, Anna A1 - Greene, Mark H. A1 - Gronwald, Jacek A1 - Guenél, Pascal A1 - Haimann, Christopher A. A1 - Hall, Per A1 - Hamann, Ute A1 - He, Wei A1 - Heyworth, Jane A1 - Hogervorst, Frans B. L. A1 - Hollestelle, Antoinette A1 - Hoover, Robert N. A1 - Hopper, John L. A1 - Hulick, Peter J. A1 - Humphreys, Keith A1 - Imyanitov, Evgeny N. A1 - Isaacs, Claudine A1 - Jakimovska, Milena A1 - Jakubowska, Anna A1 - James, Paul A. A1 - Janavicius, Ramunas A1 - Jankowitz, Rachel C. A1 - John, Esther M. A1 - Johnson, Nichola A1 - Joseph, Vijai A1 - Karlan, Beth Y. A1 - Khusnutdinova, Elza A1 - Kiiski, Johanna I. A1 - Ko, Yon-Dschun A1 - Jones, Michael E. A1 - Konstantopoulou, Irene A1 - Kristensen, Vessela N. A1 - Laitman, Yael A1 - Lambrechts, Diether A1 - Lazaro, Conxi A1 - Leslie, Goska A1 - Lester, Jenny A1 - Lesueur, Fabienne A1 - Lindström, Sara A1 - Long, Jirong A1 - Loud, Jennifer T. A1 - Lubiński, Jan A1 - Makalic, Enes A1 - Mannermaa, Arto A1 - Manoochehri, Mehdi A1 - Margolin, Sara A1 - Maurer, Tabea A1 - Mavroudis, Dimitrios A1 - McGuffog, Lesley A1 - Meindl, Alfons A1 - Menon, Usha A1 - Michailidou, Kyriaki A1 - Miller, Austin A1 - Montagna, Marco A1 - Moreno, Fernando A1 - Moserle, Lidia A1 - Mulligan, Anna Marie A1 - Nathanson, Katherine L. A1 - Neuhausen, Susan L. A1 - Nevanlinna, Heli A1 - Nevelsteen, Ines A1 - Nielsen, Finn C. A1 - Nikitina-Zake, Liene A1 - Nussbaum, Robert L. A1 - Offit, Kenneth A1 - Olah, Edith A1 - Olopade, Olufunmilayo I. A1 - Olsson, Håkan A1 - Osorio, Ana A1 - Papp, Janos A1 - Park-Simon, Tjoung-Won A1 - Parsons, Michael T. A1 - Pedersen, Inge Sokilde A1 - Peixoto, Ana A1 - Peterlongo, Paolo A1 - Pharaoh, Paul D. P. A1 - Plaseska-Karanfilska, Dijana A1 - Poppe, Bruce A1 - Presneau, Nadege A1 - Radice, Paolo A1 - Rantala, Johanna A1 - Rennert, Gad A1 - Risch, Harvey A. A1 - Saloustros, Emmanouil A1 - Sanden, Kristin A1 - Sawyer, Elinor J. A1 - Schmidt, Marjanka K. A1 - Schmutzler, Rita K. A1 - Sharma, Priyanka A1 - Shu, Xiao-Ou A1 - Simard, Jaques A1 - Singer, Christian F. A1 - Soucy, Penny A1 - Southey, Melissa C. A1 - Spinelli, John J. A1 - Spurdle, Amanda B. A1 - Stone, Jennifer A1 - Swerdlow, Anthony J. A1 - Tapper, William J. A1 - Taylor, Jack A. A1 - Teixeira, Manuel R. A1 - Terry, Mary Beth A1 - Teulé, Alex A1 - Thomassen, Mads A1 - Thöne, Kathrin A1 - Thull, Darcy L. A1 - Tischkowitz, Marc A1 - Toland, Amanda E. A1 - Torres, Diana A1 - Truong, Thérèse A1 - Tung, Nadine A1 - Vachon, Celine M. A1 - van Asperen, Christi J. A1 - van den Ouweland, Ans M. W. A1 - van Rensburg, Elizabeth J. A1 - Vega, Ana A1 - Viel, Alexandra A1 - Wang, Qin A1 - Wappenschmidt, Barbara A1 - Weitzel, Jeffrey N. A1 - Wendt, Camilla A1 - Winqvist, Robert A1 - Yang, Xiaohong R. A1 - Yannoukakos, Drakoulis A1 - Ziogas, Argyrios A1 - Kraft, Peter A1 - Antoniou, Antonis C. A1 - Zheng, Wei A1 - Easton, Douglas F. A1 - Milne, Roger L. A1 - Beesley, Jonathan A1 - Chenevix-Trench, Georgia T1 - Genome-wide association and transcriptome studies identify target genes and risk loci for breast cancer JF - Nature Communications N2 - Genome-wide association studies (GWAS) have identified more than 170 breast cancer susceptibility loci. Here we hypothesize that some risk-associated variants might act in non-breast tissues, specifically adipose tissue and immune cells from blood and spleen. Using expression quantitative trait loci (eQTL) reported in these tissues, we identify 26 previously unreported, likely target genes of overall breast cancer risk variants, and 17 for estrogen receptor (ER)-negative breast cancer, several with a known immune function. We determine the directional effect of gene expression on disease risk measured based on single and multiple eQTL. In addition, using a gene-based test of association that considers eQTL from multiple tissues, we identify seven (and four) regions with variants associated with overall (and ER-negative) breast cancer risk, which were not reported in previous GWAS. Further investigation of the function of the implicated genes in breast and immune cells may provide insights into the etiology of breast cancer. KW - cancer KW - genetics Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228024 VL - 10 ER - TY - JOUR A1 - Saalfrank, Christian A1 - Fantuzzi, Felipe A1 - Kupfer, Thomas A1 - Ritschel, Benedikt A1 - Hammond, Kai A1 - Krummenacher, Ivo A1 - Bertermann, Rüdiger A1 - Wirthensohn, Raphael A1 - Finze, Maik A1 - Schmid, Paul A1 - Engel, Volker A1 - Engels, Bernd A1 - Braunschweig, Holger T1 - cAAC‐Stabilized 9,10‐diboraanthracenes—Acenes with Open‐Shell Singlet Biradical Ground States JF - Angewandte Chemie International Edition N2 - Narrow HOMO–LUMO gaps and high charge‐carrier mobilities make larger acenes potentially high‐efficient materials for organic electronic applications. The performance of such molecules was shown to significantly increase with increasing number of fused benzene rings. Bulk quantities, however, can only be obtained reliably for acenes up to heptacene. Theoretically, (oligo)acenes and (poly)acenes are predicted to have open‐shell singlet biradical and polyradical ground states, respectively, for which experimental evidence is still scarce. We have now been able to dramatically lower the HOMO–LUMO gap of acenes without the necessity of unfavorable elongation of their conjugated π system, by incorporating two boron atoms into the anthracene skeleton. Stabilizing the boron centers with cyclic (alkyl)(amino)carbenes gives neutral 9,10‐diboraanthracenes, which are shown to feature disjointed, open‐shell singlet biradical ground states. KW - acenes KW - biradicals KW - bond Activation KW - boron KW - heterocycles Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-217795 VL - 59 IS - 43 SP - 19338 EP - 19343 ER - TY - JOUR A1 - Klein, Philipp A1 - Barthels, Fabian A1 - Johe, Patrick A1 - Wagner, Annika A1 - Tenzer, Stefan A1 - Distler, Ute A1 - Le, Thien Anh A1 - Schmid, Paul A1 - Engel, Volker A1 - Engels, Bernd A1 - Hellmich, Ute A. A1 - Opatz, Till A1 - Schirmeister, Tanja T1 - Naphthoquinones as covalent reversible inhibitors of cysteine proteases — studies on inhibition mechanism and kinetics JF - Molecules N2 - The facile synthesis and detailed investigation of a class of highly potent protease inhibitors based on 1,4-naphthoquinones with a dipeptidic recognition motif (HN-l-Phe-l-Leu-OR) in the 2-position and an electron-withdrawing group (EWG) in the 3-position is presented. One of the compound representatives, namely the acid with EWG = CN and with R = H proved to be a highly potent rhodesain inhibitor with nanomolar affinity. The respective benzyl ester (R = Bn) was found to be hydrolyzed by the target enzyme itself yielding the free acid. Detailed kinetic and mass spectrometry studies revealed a reversible covalent binding mode. Theoretical calculations with different density functionals (DFT) as well as wavefunction-based approaches were performed to elucidate the mode of action. KW - protease KW - rhodesain KW - covalent reversible inhibition KW - 1,4-naphthoquinone KW - nucleophilic addition KW - prodrug Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-203791 SN - 1420-3049 VL - 25 IS - 9 ER - TY - JOUR A1 - Saalfrank, Christian A1 - Fantuzzi, Felipe A1 - Kupfer, Thomas A1 - Ritschel, Benedikt A1 - Hammond, Kai A1 - Krummenacher, Ivo A1 - Bertermann, Rüdiger A1 - Wirthensohn, Raphael A1 - Finze, Maik A1 - Schmid, Paul A1 - Engel, Volker A1 - Engels, Bernd A1 - Braunschweig, Holger T1 - cAAC‐stabilisierte 9,10‐Diboraanthracene – offenschalige Singulettbiradikale JF - Angewandte Chemie N2 - Geringe HOMO-LUMO-Abstände und eine hohe Ladungsträgermobilität prädestinieren die höheren Acene für Anwendungen im Bereich der Organoelektronik. Die Leistungsfähigkeit derartiger Verbindungen steigt hierbei dramatisch mit der Anzahl anellierter Benzolringe. Größere Acenmengen sind synthetisch bisher jedoch nur für Acene bis Heptacen verlässlich zugänglich. Theoretischen Studien zufolge besitzen (Oligo)acene offenschalige Singulettbiradikal- und (Poly)acene polyradikalische Grundzustände. Eindeutige experimentelle Belege für diese Vorhersagen sind hingegen äußerst selten. Durch den Einbau von zwei Boratomen in das Anthracengrundgerüst konnten wir den HOMO-LUMO-Abstand von Acenen dramatisch verringern und zwar ohne die Notwendigkeit einer Ausweitung des konjugierten π-Systems. Stabilisierung der Borzentren durch cyclische (Alkyl)(amino)carbene lieferte hierbei neutrale 9,10-Diboraanthracene mit disjunkten, offenschaligen Singulettbiradikal-Grundzuständen. KW - Acene KW - Bindungsaktivierung KW - Biradikale KW - Bor KW - Heterocyclen Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218582 VL - 132 IS - 43 SP - 19502 EP - 19507 ER -