@phdthesis{Schmitt2013, author = {Schmitt, Peter}, title = {MR imaging of tumors: Approaches for functional and fast morphological characterization}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-135967}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2013}, abstract = {The subject of this work was to develop, implement, optimize and apply methods for quantitative MR imaging of tumors. In the context of functional and physiological characterization, this implied transferring techniques established in tumor model research to human subjects and assessing their feasibility for use in patients. In the context of the morphologic assessment and parameter imaging of tumors, novel concepts and techniques were developed, which facilitated the simultaneous quantification of multiple MR parameters, the generation of "synthetic" MR images with various contrasts, and the fast single-shot acquisition of purely T2-weighted images.}, subject = {Kernspintomografie}, language = {en} } @article{WeibelBasseLuesebrinkHessetal.2013, author = {Weibel, Stephanie and Basse-Luesebrink, Thomas Christian and Hess, Michael and Hofmann, Elisabeth and Seubert, Carolin and Langbein-Laugwitz, Johanna and Gentschev, Ivaylo and Sturm, Volker J{\"o}rg Friedrich and Ye, Yuxiang and Kampf, Thomas and Jakob, Peter Michael and Szalay, Aladar A.}, title = {Imaging of Intratumoral Inflammation during Oncolytic Virotherapy of Tumors by \(^{19}\)F-Magnetic Resonance Imaging (MRI)}, series = {PLoS ONE}, volume = {8}, journal = {PLoS ONE}, number = {3}, doi = {10.1371/journal.pone.0056317}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130311}, pages = {e56317}, year = {2013}, abstract = {Background Oncolytic virotherapy of tumors is an up-coming, promising therapeutic modality of cancer therapy. Unfortunately, non-invasive techniques to evaluate the inflammatory host response to treatment are rare. Here, we evaluate \(^{19}\)F magnetic resonance imaging (MRI) which enables the non-invasive visualization of inflammatory processes in pathological conditions by the use of perfluorocarbon nanoemulsions (PFC) for monitoring of oncolytic virotherapy. Methodology/Principal Findings The Vaccinia virus strain GLV-1h68 was used as an oncolytic agent for the treatment of different tumor models. Systemic application of PFC emulsions followed by \(^1H\)/\(^{19}\)F MRI of mock-infected and GLV-1h68-infected tumor-bearing mice revealed a significant accumulation of the \(^{19}\)F signal in the tumor rim of virus-treated mice. Histological examination of tumors confirmed a similar spatial distribution of the \(^{19}\)F signal hot spots and \(CD68^+\)-macrophages. Thereby, the \(CD68^+\)-macrophages encapsulate the GFP-positive viral infection foci. In multiple tumor models, we specifically visualized early inflammatory cell recruitment in Vaccinia virus colonized tumors. Furthermore, we documented that the \(^{19}\)F signal correlated with the extent of viral spreading within tumors. Conclusions/Significance These results suggest \(^{19}\)F MRI as a non-invasive methodology to document the tumor-associated host immune response as well as the extent of intratumoral viral replication. Thus, \(^{19}\)F MRI represents a new platform to non-invasively investigate the role of the host immune response for therapeutic outcome of oncolytic virotherapy and individual patient response.}, language = {en} } @article{NordbeckBoenhofHilleretal.2013, author = {Nordbeck, Peter and B{\"o}nhof, Leoni and Hiller, Karl-Heinz and Voll, Sabine and Arias-Loza, Paula and Seidlmaier, Lea and Williams, Tatjana and Ye, Yu-Xiang and Gensler, Daniel and Pelzer, Theo and Ertl, Georg and Jakob, Peter M. and Bauer, Wolfgang R. and Ritter, Oliver}, title = {Impact of Thoracic Surgery on Cardiac Morphology and Function in Small Animal Models of Heart Disease: A Cardiac MRI Study in Rats}, series = {PLoS ONE}, volume = {8}, journal = {PLoS ONE}, number = {8}, doi = {10.1371/journal.pone.0068275}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130064}, pages = {e68275}, year = {2013}, abstract = {Background Surgical procedures in small animal models of heart disease might evoke alterations in cardiac morphology and function. The aim of this study was to reveal and quantify such potential artificial early or long term effects in vivo, which might account for a significant bias in basic cardiovascular research, and, therefore, could potentially question the meaning of respective studies. Methods Female Wistar rats (n = 6 per group) were matched for weight and assorted for sham left coronary artery ligation or control. Cardiac morphology and function was then investigated in vivo by cine magnetic resonance imaging at 7 Tesla 1 and 8 weeks after the surgical procedure. The time course of metabolic and inflammatory blood parameters was determined in addition. Results Compared to healthy controls, rats after sham surgery showed a lower body weight both 1 week (267.5±10.6 vs. 317.0±11.3 g, n<0.05) and 8 weeks (317.0±21.1 vs. 358.7±22.4 g, n<0.05) after the intervention. Left and right ventricular morphology and function were not different in absolute measures in both groups 1 week after surgery. However, there was a confined difference in several cardiac parameters normalized to the body weight (bw), such as myocardial mass (2.19±0.30/0.83±0.13 vs. 1.85±0.22/0.70±0.07 mg left/right per g bw, p<0.05), or enddiastolic ventricular volume (1.31±0.36/1.21±0.31 vs. 1.14±0.20/1.07±0.17 µl left/right per g bw, p<0.05). Vice versa, after 8 weeks, cardiac masses, volumes, and output showed a trend for lower values in sham operated rats compared to controls in absolute measures (782.2±57.2/260.2±33.2 vs. 805.9±84.8/310.4±48.5 mg, p<0.05 for left/right ventricular mass), but not normalized to body weight. Matching these findings, blood testing revealed only minor inflammatory but prolonged metabolic changes after surgery not related to cardiac disease. Conclusion Cardio-thoracic surgical procedures in experimental myocardial infarction cause distinct alterations upon the global integrity of the organism, which in the long term also induce circumscribed repercussions on cardiac morphology and function. This impact has to be considered when analyzing data from respective animal studies and transferring these findings to conditions in patients.}, language = {en} } @article{OostingaMaierSchueffelgenetal.2013, author = {Oostinga, Jeroen B. and Maier, Luis and Sch{\"u}ffelgen, Peter and Knott, Daniel and Ames, Christopher and Br{\"u}ne, Christoph and Tkachov, Grigory and Buhmann, Hartmut and Molenkamp, Laurens W.}, title = {Josephson Supercurrent through the Topological Surface States of Strained Bulk HgTe}, series = {Physical Review X}, volume = {3}, journal = {Physical Review X}, number = {021007}, doi = {10.1103/PhysRevX.3.021007}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129834}, year = {2013}, abstract = {Strained bulk HgTe is a three-dimensional topological insulator, whose surface electrons have a high mobility (~ 30 000 cm\(^2\)=Vs), while its bulk is effectively free of mobile charge carriers. These properties enable a study of transport through its unconventional surface states without being hindered by a parallel bulk conductance. Here, we show transport experiments on HgTe-based Josephson junctions to investigate the appearance of the predicted Majorana states at the interface between a topological insulator and a superconductor. Interestingly, we observe a dissipationless supercurrent flow through the topological surface states of HgTe. The current-voltage characteristics are hysteretic at temperatures below 1 K, with critical supercurrents of several microamperes. Moreover, we observe a magnetic-field-induced Fraunhofer pattern of the critical supercurrent, indicating a dominant \(2\pi\)-periodic Josephson effect in the unconventional surface states. Our results show that strained bulk HgTe is a promising material system to get a better understanding of the Josephson effect in topological surface states, and to search for the manifestation of zero-energy Majorana states in transport experiments.}, language = {en} } @article{ScholzSauerWiessneretal.2013, author = {Scholz, M. and Sauer, C. and Wiessner, M. and Nguyen, N. and Scholl, A. and Reinert, F.}, title = {Structure formation in organic thin films observed in real time by energy dispersive near-edge x-ray absorption fine-structure spectroscopy}, series = {New Journal of Physics}, volume = {15}, journal = {New Journal of Physics}, number = {083052}, doi = {10.1088/1367-2630/15/8/083052}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129749}, year = {2013}, abstract = {We study the structure formation of 1,4,5,8-naphthalenetetracarboxylicacid- dianhydride (NTCDA) multilayer films on Ag(111) surfaces by energy dispersive near-edge x-ray absorption fine-structure spectroscopy (NEXAFS) and photoelectron spectroscopy. The time resolution of seconds of the method allows us to identify several sub-processes, which occur during the post-growth three-dimensional structural ordering, as well as their characteristic time scales. After deposition at low temperature the NTCDA molecules are preferentially flat lying and the films exhibit no long-range order. Upon annealing the molecules flip into an upright orientation followed by an aggregation in a transient phase which exists for several minutes. Finally, threedimensional islands are established with bulk-crystalline structure involving substantial mass transport on the surface and morphological roughening. By applying the Kolmogorov-Johnson-Mehl-Avrami model the activation energies of the temperature-driven sub-processes can be derived from the time evolution of the NEXAFS signal.}, language = {en} } @article{BentmannReinert2013, author = {Bentmann, Hendrik and Reinert, Friedrich}, title = {Enhancing and reducing the Rashba-splitting at surfaces by adsorbates: Na and Xe on Bi/Cu(111)}, series = {New Journal of Physics}, volume = {15}, journal = {New Journal of Physics}, number = {115011}, doi = {10.1088/1367-2630/15/11/115011}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129722}, year = {2013}, abstract = {The surface alloy Bi/Cu(111) shows a paradigmatic free-electron-like surface state with a very large Rashba-type spin-orbit splitting. Using angle-resolved photoemission we investigate how adsorbates of different chemical nature influence the size of the spin splitting in this system. We find that the adsorption of small amounts of monovalent Na atoms leads to an enhancement of the spin splitting while an overlayer of the closed-shell rare gas Xe causes a reduction. The latter result is in contrast to the Au(111) surface for which an increased splitting size after Xe-adsorption was observed. We discuss these experimental findings in terms of the characteristic differences of the surface state wave functions and their spatial deformation in the presence of different types of adsorbates. Our results provide insight into the complex interplay of atomic and interface potential gradients governing the Rashba effect.}, language = {en} } @article{ThierschmannHenkeKnorretal.2013, author = {Thierschmann, H. and Henke, M. and Knorr, J. and Maier, L. and Heyn, C. and Hansen, W. and Buhmann, H. and Molenkamp, L. W.}, title = {Diffusion thermopower of a serial double quantum dot}, series = {New Journal of Physics}, volume = {15}, journal = {New Journal of Physics}, number = {123010}, doi = {10.1088/1367-2630/15/12/123010}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129714}, year = {2013}, abstract = {We have experimentally studied the diffusion thermopower of a serial double quantum dot, defined electrostatically in a GaAs/AlGaAs heterostructure. We present the thermopower stability diagram for a temperature difference 1T = (20±10)mK across the device and find a maximum thermovoltage signal of several μV in the vicinity of the triple points. Along a constant energy axis in this regime, the data show a characteristic pattern which is in agreement with Mott's relation and can be well understood within a model of sequential transport.}, language = {en} } @article{OPUS4-13156, title = {Search for WH production with a light Higgs boson decaying to prompt electron-jets in proton-proton collisions at \(\sqrt {s}=7\)  TeV with the ATLAS detector}, series = {New Journal of Physics}, volume = {15}, journal = {New Journal of Physics}, number = {043009}, organization = {The ATLAS Collaboration}, doi = {10.1088/1367-2630/15/4/043009}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131565}, year = {2013}, abstract = {A search is performed for WH production with a light Higgs boson decaying to hidden-sector particles resulting in clusters of collimated electrons, known as electron-jets. The search is performed with \(2.04 fb^{-1}\) of data collected in 2011 with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at \(\sqrt {s}=7 TeV\) . One event satisfying the signal selection criteria is observed, which is consistent with the expected background rate. Limits on the product of the WH production cross section and the branching ratio of a Higgs boson decaying to prompt electron-jets are calculated as a function of a Higgs boson mass in the range from 100 to 140 GeV.}, language = {en} } @article{OPUS4-13155, title = {Search for excited electrons and muons in \(\sqrt {s}=8\) TeV proton-proton collisions with the ATLAS detector}, series = {New Journal of Physics}, volume = {15}, journal = {New Journal of Physics}, number = {093011}, organization = {The ATLAS Collaboration}, doi = {10.1088/1367-2630/15/9/093011}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131557}, year = {2013}, abstract = {The ATLAS detector at the Large Hadron Collider is used to search for excited electrons and excited muons in the channel \(pp →ℓℓ^\ast→ℓℓ\gamma \), assuming that excited leptons are produced via contact interactions. The analysis is based on \(13 fb^{-1}\) of pp collisions at a centre-of-mass energy of 8 TeV. No evidence for excited leptons is found, and a limit is set at the 95\% credibility level on the cross section times branching ratio as a function of the excitedlepton mass \(m_{ℓ^\ast}\) . For \(m_{ℓ^\ast}\) ≽0.8 TeV, the respective upper limits on \(\sigma B(ℓ→ ℓ\gamma)\) are 0.75 and 0.90 fb for the \(e^\ast\) and \(μ^\ast\) searches. Limits on \(\sigma B\) are converted into lower bounds on the compositeness scale \(\Lambda\). In the special case where \(\Lambda = m_{ℓ^\ast}\), excited-electron and excited-muon masses below 2.2 TeV are excluded.}, language = {en} } @article{OPUS4-13154, title = {Search for extra dimensions in diphoton events from proton-proton collisions at \(\sqrt {s} = 7\)  TeV in the ATLAS detector at the LHC}, series = {New Journal of Physics}, volume = {15}, journal = {New Journal of Physics}, organization = {The ATLAS Collaboration}, doi = {10.1088/1367-2630/15/4/043007}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131548}, pages = {043007}, year = {2013}, abstract = {The large difference between the Planck scale and the electroweak scale, known as the hierarchy problem, is addressed in certain models through the postulate of extra spatial dimensions. A search for evidence of extra spatial dimensions in the diphoton channel has been performed using the full set of proton-proton collisions at \(\sqrt {s} = 7\) TeV recorded in 2011 with the ATLAS detector at the CERN Large Hadron Collider. This dataset corresponds to an integrated luminosity of \(4.9 fb^{-1}\). The diphoton invariant mass spectrum is observed to be in good agreement with the Standard Model expectation. In the context of the model proposed by Arkani-Hamed, Dimopoulos and Dvali, 95\% confidence level lower limits of between 2.52 and 3.92 TeV are set on the ultraviolet cutoff scale MS depending on the number of extra dimensions and the theoretical formalism used. In the context of the Randall-Sundrum model, a lower limit of 2.06 (1.00) TeV at 95\% confidence level is set on the mass of the lightest graviton for couplings of \(k/\overline {M}_{Pl} = 0.1 (0.01)\). Combining with the ATLAS dilepton searches based on the 2011 data, the 95\% confidence level lower limit on the Randall-Sundrum graviton mass is further tightened to 2.23 (1.03) TeV for \(k/\overline {M}_{Pl} = 0.1 (0.01)\).}, language = {en} }