TY - JOUR A1 - Kraff, Oliver A1 - Bitz, Andreas A1 - Breyer, Tobias A1 - Kruszona, Stefan A1 - Maderwald, Stefan A1 - Brote, Irina A1 - Gizewski, Elke R. A1 - Ladd, Mark E. A1 - Quick, Harald H. T1 - A transmit/receive radiofrequency array for imaging the carotid arteries at 7 Tesla: coil design and first in vivo results JF - Investigative Radiology N2 - Objective: To develop a transmit/receive radiofrequency (RF) array for magnetic resonance imaging (MRI) of the carotid arteries at 7 T. The prototype is characterized in numerical simulations and bench measurements, and the feasibility of plaque imaging at 7 T is demonstrated in first in vivo images. Materials and Methods: The RF phased array coil consists of 8 surface loop coils. To allow imaging of both sides of the neck, the RF array is divided into 2 coil clusters, each with 4 overlapping loop elements. For safety validation, numerical computations of the RF field distribution and the corresponding specific absorption rate were performed on the basis of a heterogeneous human body model. To validate the coil model, maps of the transmit B1+ field were compared between simulation and measurement. In vivo images of a healthy volunteer and a patient (ulcerating plaque and a 50% stenosis of the right internal carotid artery) were acquired using a 3-dimensional FLASH sequence with a high isotropic spatial resolution of 0.54 mm as well as using pulse-triggered proton density (PD)/T2-weighted turbo spin echo sequences. Results: Measurements of the S-parameters yielded a reflection and isolation of the coil elements of better than −18 and −13 dB, respectively. Measurements of the g-factor indicated good image quality for parallel imaging acceleration factors up to 2.4. A similar distribution and a very good match of the absolute values were found between the measured and simulated B1+ transmit RF field for the validation of the coil model. In vivo images revealed good signal excitation of both sides of the neck and a high vessel-to-background image contrast for the noncontrast-enhanced 3-dimensional FLASH sequence. Imaging at 7 T could depict the extent of stenosis, and revealed the disruption and ulcer of the plaque. Conclusions: This study demonstrates that 2 four-channel transmit/receive RF arrays for each side of the neck is a suitable concept for in vivo MRI of the carotid arteries at 7 Tesla. Further studies are needed to explore and exploit the full potential of 7 T high-field MRI for carotid atherosclerotic plaque imaging. Y1 - 2011 U6 - https://doi.org/10.1097/RLI.0b013e318206cee4 SN - 1536-0210 VL - 46 IS - 4 SP - 246 EP - 254 PB - Wolters Kluwer CY - Köln ER - TY - JOUR A1 - El Quardi, A. A1 - Streckert, J. A1 - Bitz, Andreas A1 - Münkner, S. A1 - Engel, J. A1 - Hansen, V. T1 - New fin-line devices for radiofrequency exposure of small biological samples in vitro allowing whole-cell patch clamp recordings JF - Bioelectromagnetics N2 - The development and analysis of three waveguides for the exposure of small biological in vitro samples to mobile communication signals at 900 MHz (GSM, Global System for Mobile Communications), 1.8 GHz (GSM), and 2 GHz (UMTS, Universal Mobile Telecommunications System) is presented. The waveguides were based on a fin-line concept and the chamber containing the samples bathed in extracellular solution was placed onto two fins with a slot in between, where the exposure field concentrates. Measures were taken to allow for patch clamp recordings during radiofrequency (RF) exposure. The necessary power for the achievement of the maximum desired specific absorption rate (SAR) of 20 W/kg (average over the mass of the solution) was approximately Pin = 50 mW, Pin = 19 mW, and Pin = 18 mW for the 900 MHz, 1800 MHz, and 2 GHz devices, respectively. At 20 W/kg, a slight RF-induced temperature elevation in the solution of no more than 0.3 °C was detected, while no thermal offsets due to the electromagnetic exposure could be detected at the lower SAR settings (2, 0.2, and 0.02 W/kg). A deviation of 10% from the intended solution volume yielded a calculated SAR deviation of 8% from the desired value. A maximum ±10% variation in the local SAR could occur when the position of the patch clamp electrode was altered within the area where the cells to be investigated were located. Y1 - 2011 U6 - https://doi.org/10.1002/bem.20621 SN - 1521-186X VL - 32 IS - 2 SP - 102 EP - 112 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Umutlu, Lale A1 - Orzada, Stephan A1 - Kinner, Sonja A1 - Maderwald, Stefan A1 - Bronte, Irina A1 - Bitz, Andreas A1 - Kraff, Oliver A1 - Ladd, Susanne C. A1 - Antoch, Gerald A1 - Ladd, Mark E. A1 - Quick, Harald H. A1 - Lauenstein, Thomas C. T1 - Renal imaging at 7 Tesla: preliminary results JF - European Radiology N2 - Objective To investigate the feasibility of 7T MR imaging of the kidneys utilising a custom-built 8-channel transmit/receive radiofrequency body coil. Methods In vivo unenhanced MR was performed in 8 healthy volunteers on a 7T whole-body MR system. After B0 shimming the following sequences were obtained: 1) 2D and 3D spoiled gradient-echo sequences (FLASH, VIBE), 2) T1-weighted 2D in and opposed phase 3) True-FISP imaging and 4) a T2-weighted turbo spin echo (TSE) sequence. Visual evaluation of the overall image quality was performed by two radiologists. Results Renal MRI at 7T was feasible in all eight subjects. Best image quality was found using T1-weighted gradient echo MRI, providing high anatomical details and excellent conspicuity of the non-enhanced vasculature. With successful shimming, B1 signal voids could be effectively reduced and/or shifted out of the region of interest in most sequence types. However, T2-weighted TSE imaging remained challenging and strongly impaired because of signal heterogeneities in three volunteers. Conclusion The results demonstrate the feasibility and diagnostic potential of dedicated 7T renal imaging. Further optimisation of imaging sequences and dedicated RF coil concepts are expected to improve the acquisition quality and ultimately provide high clinical diagnostic value. Y1 - 2011 SN - 1432-1084 VL - 21 IS - 4 SP - 841 EP - 849 PB - Springer CY - Berlin ER - TY - JOUR A1 - Tran, Duc Hung T1 - Corporate Governance und Eigenkapitalkosten - Bestandsaufnahme des Schrifttums unter besonderer Berücksichtigung des Informationsaspektes und Forschungsperspektiven JF - Zeitschrift für Betriebswirtschaft Y1 - 2018 U6 - https://doi.org/10.1007/s11573-011-0461-z SN - 1861-8928 VL - 81 SP - 551 EP - 585 PB - Springer CY - Berlin ER - TY - JOUR A1 - Tran, Duc Hung T1 - Die Bilanzierung immaterieller Vermögensgegenstände nach BilMoG: Normative Erkenntnisse empirischer Befunde JF - KoR Zeitschrift für kapitalmarktorientierte Rechnungslegung Y1 - 2018 SN - 1437-8981 VL - 11 SP - 538 EP - 542 ER - TY - JOUR A1 - Tran, Duc Hung T1 - Wirkungslosigkeit der Entsprechenserklärung gem. §161 AktG JF - Betriebs-Berater: BB ; Recht, Wirtschaft, Steuern N2 - Das Ziel des Deutschen Corporate Governance Kodex (DCGK) besteht in der Verbesserung der Transparenz und Qualität der deutschen Corporate Governance, wobei die Sanktionierung der Nichteinhaltung des DCGK einzig durch etwaige Kapitalmarktreaktionen erfolgt. Folgende Befunde sprechen jedoch dafür, dass durch die Abgabe der Entsprechenserklärung gem. § 161 AktG die für das Enforcement des Kodex angenommene Selbstregulierung durch den Kapitalmarkt nicht stattfindet, und demnach Verbesserungsbedarf besteht Y1 - 2018 SN - 0340-7918 N1 - gedruckt in der Bereichsbibliothek Eupener Str. unter der Signatur 43 Z 228 VL - 66 SP - 2025 PB - Beck CY - München ER - TY - JOUR A1 - Kroll-Ludwigs, Kathrin T1 - Anmerkung zu EuGH, Urt. v. 1.3.2011, Rs. C-236/09 Association belge des Consomma-teurs Test-Achats JF - JuristenZeitung (JZ) Y1 - 2011 U6 - https://doi.org/10.1628/002268811796448996 SN - 1868-7067 VL - 66 IS - 14 SP - 734 EP - 737 PB - Mohr Siebeck CY - Tübingen ER - TY - JOUR A1 - Kroll-Ludwigs, Kathrin T1 - Anmerkung zu EuGH, Urt. v. 22. 12. 2010, Rs. C-208/09 - Sayn-Wittgenstein JF - GPR : Zeitschrift für das Privatrecht der Europäischen Union Y1 - 2011 U6 - https://doi.org/10.1515/gpr.2011.8.5.242 SN - 2193-9519 IS - 5 SP - 242 EP - 245 PB - Verlag Dr. Otto Schmidt CY - Köln ER - TY - JOUR A1 - Deppe, Veronika Maria A1 - Bongaerts, Johannes A1 - O'Connell, Timothy A1 - Maurer, Karl-Heinz A1 - Meinhardt, Friedhelm T1 - Enzymatic deglycation of Amadori products in bacteria JF - Applied microbiology and biotechnology Y1 - 2011 SN - 1432-0614 (E-Journal); 0171-1741 (Print); 0175-7598 (Print); 0340-2118 (Print) VL - Vol. 90 IS - Iss. 2 SP - 399 EP - 406 PB - Springer CY - Berlin ER - TY - JOUR A1 - Norda, Hannah A1 - Butenweg, Christoph T1 - Möglichkeiten und Grenzen der Anwendbarkeit statisch nichtlinearer Verfahren nach DIN EN 1998-1 JF - Bauingenieur : die richtungsweisende Zeitschrift im Bauingenieurswesen ; offizielle Zeitschrift der VDI-Gesellschaft Bautechnik. Beilage: D-A-CH-Mitteilungsblatt Y1 - 2011 SN - 1436-4867 (E-Journal); 0005-6650 (Print) N1 - Printausgabe in der Bibliothek Bayernallee vorhanden: 13 Z 049-2011 VL - Band 86 SP - S13 EP - S21 PB - VDI Fachmedien CY - Düsseldorf ER -