TY - JOUR A1 - Olbertz, Klaus A1 - Thiergart, Kirsten T1 - Börsengang leicht gemacht? Gesellschafts- und arbeitsrechtliche Aspekte bei Übernahme und Verschmelzung eines Zielunternehmens auf die SPAC in der Rechtsform der SE JF - Betriebs-Berater: BB ; Recht, Wirtschaft, Steuern N2 - Die SPAC-SE ist börsenfähig und damit eine für eine SPAC grundsätzlich geeignete Rechtsform. Die Tatsache, dass es sich hierbei (zunächst) um eine leere, arbeitnehmerlose Hülle handelt, ändert hieran nichts. Die Gründung einer solchen Vorrats-SE ist trotz fehlender Arbeitnehmerbeteiligung unter teleologischer Reduktion von Art. 12 II SE-VO zulässig. Im Gegenzug muss die Arbeitnehmerbeteiligung gemaß § 18 III SEBG analog nachgeholt werden, wenn das später erworbene Zielunternehmen auf die SPAC-SE verschmolzen werden soll. Aus gesellschaftsrechtlicher Sicht ist zu beachten, dass die SPAC-SE mit Sitz in Deutschland, welche auch den deutschen, aktienrechtlichen Bestimmungen unterliegt, nur bedingt für eine SPAC geeignet erscheint. Das deutsche Aktienrecht enthält strenge Regelungen, die der für eine SPAC-SE erforderlichen Flexibilität entgegenstehen können. Dies gilt insbesondere für das Erfordernis der Zustimmung der Hauptversammlung zur Akquisition des Zielunternehmens, die Rückzahlung des Treuhandvermögens an Aktionäre, die der Akquisition nicht zugestimmt haben und die Liquidation der SPAC-SE im Falle des Scheiterns des Erwerbs des Zielobjektes. Y1 - 2018 SN - 0340-7918 SP - 1547 PB - Beck CY - München ER - TY - CHAP A1 - Olderog, M. A1 - Mohr, P. A1 - Beging, Stefan A1 - Tsoumpas, C. A1 - Ziemons, Karl T1 - Simulation study on the role of tissue-scattered events in improving sensitivity for a compact time of flight compton positron emission tomograph T2 - 2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) N2 - In positron emission tomography improving time, energy and spatial detector resolutions and using Compton kinematics introduces the possibility to reconstruct a radioactivity distribution image from scatter coincidences, thereby enhancing image quality. The number of single scattered coincidences alone is in the same order of magnitude as true coincidences. In this work, a compact Compton camera module based on monolithic scintillation material is investigated as a detector ring module. The detector interactions are simulated with Monte Carlo package GATE. The scattering angle inside the tissue is derived from the energy of the scattered photon, which results in a set of possible scattering trajectories or broken line of response. The Compton kinematics collimation reduces the number of solutions. Additionally, the time of flight information helps localize the position of the annihilation. One of the questions of this investigation is related to how the energy, spatial and temporal resolutions help confine the possible annihilation volume. A comparison of currently technically feasible detector resolutions (under laboratory conditions) demonstrates the influence on this annihilation volume and shows that energy and coincidence time resolution have a significant impact. An enhancement of the latter from 400 ps to 100 ps leads to a smaller annihilation volume of around 50%, while a change of the energy resolution in the absorber layer from 12% to 4.5% results in a reduction of 60%. The inclusion of single tissue-scattered data has the potential to increase the sensitivity of a scanner by a factor of 2 to 3 times. The concept can be further optimized and extended for multiple scatter coincidences and subsequently validated by a reconstruction algorithm. Y1 - 2021 SN - 978-1-7281-7693-2 U6 - https://doi.org/10.1109/NSS/MIC42677.2020.9507901 N1 - 2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 31 Oct.-7 Nov. 2020, Boston, MA, USA PB - IEEE CY - New York, NY ER - TY - JOUR A1 - Oliveira, Danilo A. A1 - Molinnus, Denise A1 - Beging, Stefan A1 - Siqueira Jr, José R. A1 - Schöning, Michael Josef T1 - Biosensor Based on Self-Assembled Films of Graphene Oxide and Polyaniline Using a Field-Effect Device Platform JF - physica status solidi (a) applications and materials science N2 - A new functionalization method to modify capacitive electrolyte–insulator–semiconductor (EIS) structures with nanofilms is presented. Layers of polyallylamine hydrochloride (PAH) and graphene oxide (GO) with the compound polyaniline:poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PANI:PAAMPSA) are deposited onto a p-Si/SiO2 chip using the layer-by-layer technique (LbL). Two different enzymes (urease and penicillinase) are separately immobilized on top of a five-bilayer stack of the PAH:GO/PANI:PAAMPSA-modified EIS chip, forming a biosensor for detection of urea and penicillin, respectively. Electrochemical characterization is performed by constant capacitance (ConCap) measurements, and the film morphology is characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). An increase in the average sensitivity of the modified biosensors (EIS–nanofilm–enzyme) of around 15% is found in relation to sensors, only carrying the enzyme but without the nanofilm (EIS–enzyme). In this sense, the nanofilm acts as a stable bioreceptor onto the EIS chip improving the output signal in terms of sensitivity and stability. KW - capacitive electrolyte–insulator–semiconductor sensors KW - graphene oxide KW - layer-by-layer technique KW - nanomaterials KW - polyaniline Y1 - 2021 U6 - https://doi.org/10.1002/pssa.202000747 SN - 1862-6319 N1 - Corresponding author: José R. Siqueira Jr & Michael J. Schöning VL - 218 IS - 13 SP - 1 EP - 9 PB - Wiley-VCH CY - Weinheim ER - TY - BOOK A1 - Olk, Ulrich T1 - Entwicklung eines Struktur- und Ablaufmodells für industrialisiertes Bauen Y1 - 1980 N1 - Dortmund, Univ., Diss., 1980 ER - TY - JOUR A1 - Olk, Ulrich T1 - Arbeitsvorbereitung und Ablaufplanung JF - Zahlentafeln für den Baubetrieb / Hoffmann, Manfred ; Kuhlmann, Willy [Hrsg.]. 7., vollst. überarb. Aufl. Y1 - 2006 SN - 3-519-65220-X N1 - Kapitel 8 SP - 547 EP - 580 PB - Teubner CY - Wiesbaden ER - TY - JOUR A1 - Olk, Ulrich T1 - Unfallverhütung JF - Zahlentafeln für den Baubetrieb / Hoffmann, Manfred ; Kuhlmann, Willy [Hrsg.]. 7., vollst. überarb. Aufl. Y1 - 2006 SN - 3-519-65220-X N1 - Kapitel 14 SP - 833 EP - 929 PB - Teubner CY - Wiesbaden ER - TY - JOUR A1 - Olk, Ulrich T1 - Arbeitsvorbereitung und Ablaufplanung JF - Beispiele für die Baubetriebspraxis / Hoffmann, Manfred ; Kuhlmann, Willy [Hrsg.]. Y1 - 2006 SN - 978-3-8351-0002-2 N1 - Kapitel 5 SP - 63 EP - 88 PB - Teubner CY - Wiesbaden ER - TY - BOOK A1 - Olk, Ulrich A1 - Bauer, Hermann T1 - Entwicklung von Kriterien für den optimalen Ablauf aller Teilvorgänge des industrialisierten Bauens : Forschungsbericht / Hermann Bauer ; Ulrich Olk Y1 - 1979 PB - Lehrstuhl für Baubetrieb und Baumaschinen, Univ. CY - Dortmund ER - TY - BOOK A1 - Olk, Ulrich A1 - Bauer, Hermann T1 - Sicherheitstechnische Anforderungen beim Ablauf von Hochbauvorhaben / H. Bauer ; U. Olk Y1 - 1983 SN - 3-88314-324-3 N1 - Forschungsbericht / Bundesanstalt für Arbeitsschutz ; 369 PB - Wirtschaftsverl. NW, Verl. für neue Wiss. CY - Bremerhaven ER - TY - THES A1 - Oltmanns, Maireni T1 - Digitale Medien wollen gelernt sein : Kampagne für die "Medienscouts NRW" zur Kompetenzförderung N2 - ,,Digitale Medien wollen gelernt sein" ist eine Kampagne für das Projekt Medienscouts. Hier werden im ersten Schritt interessierte Schüler:innen an weiterführenden Schulen zu Medienexpert:innen ausgebildet. Im Zweiten geben sie ihr Wissen an ihre Mitschüler:innen weiter und fungieren in ihren Schulen als gleichaltrige Ansprechpartner:innen bei Fragen oder Problemen. Um weitere Schüler:innen für das Projekt zu werben, konzentriert sich die Kampagne auf eine altersgerechte Social Media-Präsenz. Ebenso wie das Projekt gibt auch die Kampagne den teilnehmenden Medienscouts die Freiheit, ihre Erfahrungen und Tipps zu teilen. Hierzu ist ein praktikables Konzept entworfen worden, mit dem die Scouts fortlaufend ihre offiziellen Kanäle bespielen können. KW - Medienkompetenz KW - Medienscouts KW - Social Media Kampagne Y1 - 2023 PB - FH Aachen CY - Aachen ER - TY - JOUR A1 - Oosterhuis, Koen A1 - Öhlschläger, Peter A1 - Berg, Joost H. van den A1 - Toebes, Mireille A1 - Gomez, Raquel A1 - Schumacher, Ton N. A1 - Haanen, John B. T1 - Preclinical development of highly effective and safe DNA vaccines directed against HPV 16 E6 and E7 JF - International Journal of Cancer Y1 - 2011 SN - 1097-0215 VL - 129 IS - 2 SP - 397 EP - 406 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Ortner, Marion A1 - Hauser, Christine A1 - Schmaderer, Christoph A1 - Muggenthaler, Claudia A1 - Hapfelmeier, Alexander A1 - Sorg, Christian A1 - Diehl-Schmid, Janine A1 - Kurz, Alexander A1 - Förstl, Hans A1 - Ikenberg, Benno A1 - Kotliar, Konstantin A1 - Holger, Poppert A1 - Grimmer, Timo T1 - Decreased vascular pulsatility in Alzheimer’s disease dementia measured by transcranial color-coded duplex sonography JF - Neuropsychiatric disease and treatment N2 - Purpose: Impaired paravascular drainage of β-Amyloid (Aβ) has been proposed as a contributing cause for sporadic Alzheimer’s disease (AD), as decreased cerebral blood vessel pulsatility and subsequently reduced propulsion in this pathway could lead to the accumulation and deposition of Aβ in the brain. Therefore, we hypothesized that there is an increased impairment in pulsatility across AD spectrum. Patients and Methods: Using transcranial color-coded duplex sonography (TCCS) the resistance and pulsatility index (RI; PI) of the middle cerebral artery (MCA) in healthy controls (HC, n=14) and patients with AD dementia (ADD, n=12) were measured. In a second step, we extended the sample by adding patients with mild cognitive impairment (MCI) stratified by the presence (MCI-AD, n=8) or absence of biomarkers (MCI-nonAD, n=8) indicative for underlying AD pathology, and compared RI and PI across the groups. To control for atherosclerosis as a confounder, we measured the arteriolar-venular-ratio of retinal vessels. Results: Left and right RI (p=0.020; p=0.027) and left PI (p=0.034) differed between HC and ADD controlled for atherosclerosis with AUCs of 0.776, 0.763, and 0.718, respectively. The RI and PI of MCI-AD tended towards ADD, of MCI-nonAD towards HC, respectively. RIs and PIs were associated with disease severity (p=0.010, p=0.023). Conclusion: Our results strengthen the hypothesis that impaired pulsatility could cause impaired amyloid clearance from the brain and thereby might contribute to the development of AD. However, further studies considering other factors possibly influencing amyloid clearance as well as larger sample sizes are needed. Y1 - 2019 U6 - https://doi.org/10.2147/NDT.S225754 SN - 1178-2021 IS - 15 SP - 3487 EP - 3499 PB - Dove Medical Press CY - Albany, Auckland ER - TY - JOUR A1 - Orzada, S. A1 - Maderwald, S. A1 - Poser, B. A. A1 - Johst, S. A1 - Kannengiesser, S. A1 - Ladd, M. E. A1 - Bitz, Andreas T1 - Time-interleaved acquisition of modes: an analysis of SAR and image contrast implications JF - Magnetic Resonance in Medicine N2 - s the magnetic field strength and therefore the operational frequency in MRI are increased, the radiofrequency wavelength approaches the size of the human head/body, resulting in wave effects which cause signal decreases and dropouts. Especially, whole-body imaging at 7 T and higher is therefore challenging. Recently, an acquisition scheme called time-interleaved acquisition of modes has been proposed to tackle the inhomogeneity problems in high-field MRI. The basic premise is to excite two (or more) different Burn:x-wiley:07403194:media:MRM23081:tex2gif-stack-1 modes using static radiofrequency shimming in an interleaved acquisition, where the complementary radiofrequency patterns of the two modes can be exploited to improve overall signal homogeneity. In this work, the impact of time-interleaved acquisition of mode on image contrast as well as on time-averaged specific absorption rate is addressed in detail. Time-interleaved acquisition of mode is superior in Burn:x-wiley:07403194:media:MRM23081:tex2gif-stack-2 homogeneity compared with conventional radiofrequency shimming while being highly specific absorption rate efficient. Time-interleaved acquisition of modes can enable almost homogeneous high-field imaging throughout the entire field of view in PD, T2, and T2*-weighted imaging and, if a specified homogeneity criterion is met, in T1-weighted imaging as well. Y1 - 2012 U6 - https://doi.org/10.1002/mrm.23081 SN - 1522-2594 VL - 67 IS - 4 SP - 1033 EP - 1041 PB - Wiley-Liss CY - New York ER - TY - JOUR A1 - Orzada, Stephan A1 - Bitz, Andreas A1 - Johst, Sören A1 - Gratz, Marcel A1 - Völker, Maximilian N. A1 - Kraff, Oliver A1 - Abuelhaija, Ashraf A1 - Fiedler, Thomas M. A1 - Solbach, Klaus A1 - Quick, Harald H. A1 - Ladd, Mark E. T1 - Analysis of an integrated 8-Channel Tx/Rx body array for use as a body coil in 7-Tesla MRI JF - Frontiers in Physics Y1 - 2017 U6 - https://doi.org/10.3389/fphy.2017.00017 SN - 2296-424X N1 - Article number 17 VL - 5 IS - Jun ER - TY - JOUR A1 - Orzada, Stephan A1 - Bitz, Andreas A1 - Schäfer, Lena C. A1 - Ladd, Susanne C. A1 - Ladd, Mark E. A1 - Maderwald, Stefan T1 - Open design eight-channel transmit/receive coil for high-resolution and real-time ankle imaging at 7 T JF - Medical Physics N2 - Purpose: At 1.5 T, real-time MRI of joint movement has been shown to be feasible. However, 7 T, provides higher SNR and thus an improved potential for parallel imaging acceleration. The purpose of this work was to build an open, U-shaped eight-channel transmit/receive microstrip coil for 7 T MRI to enable high-resolution and real-time imaging of the moving ankle joint. Methods: A U-shaped eight-channel transmit/receive array for the human ankle was built.urn:x-wiley:00942405:mp3399:equation:mp3399-math-0001-parameters and urn:x-wiley:00942405:mp3399:equation:mp3399-math-0002-factor were measured. SAR calculations of different ankle postures were performed to ensure patient safety. Inhomogeneities in the transmit field consequent to the open design were compensated for by the use of static RF shimming. High-resolution and real-time imaging was performed in human volunteers. Results: The presented array showed good performance with regard to patient comfort and image quality. High acceleration factors of up to 4 are feasible without visible acceleration artifacts. Reasonable image homogeneity was achieved with RF shimming. Conclusions: Open, noncylindrical designs for transmit/receive coils are practical at 7 T and real-time imaging of the moving joint is feasible with the presented coil design. Y1 - 2011 U6 - https://doi.org/10.1118/1.3553399 SN - 2473-4209 VL - 38 IS - 3 SP - 1162 EP - 1167 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Orzada, Stephan A1 - Fiedler, Thomas M. A1 - Bitz, Andreas A1 - Ladd, Mark E. A1 - Quick, Harald H. T1 - Local SAR compression with overestimation control to reduce maximum relative SAR overestimation and improve multi-channel RF array performance JF - Magnetic Resonance Materials in Physics, Biology and Medicine N2 - Objective In local SAR compression algorithms, the overestimation is generally not linearly dependent on actual local SAR. This can lead to large relative overestimation at low actual SAR values, unnecessarily constraining transmit array performance. Method Two strategies are proposed to reduce maximum relative overestimation for a given number of VOPs. The first strategy uses an overestimation matrix that roughly approximates actual local SAR; the second strategy uses a small set of pre-calculated VOPs as the overestimation term for the compression. Result Comparison with a previous method shows that for a given maximum relative overestimation the number of VOPs can be reduced by around 20% at the cost of a higher absolute overestimation at high actual local SAR values. Conclusion The proposed strategies outperform a previously published strategy and can improve the SAR compression where maximum relative overestimation constrains the performance of parallel transmission. Y1 - 2020 SN - 1352-8661 U6 - https://doi.org/10.1007/s10334-020-00890-0 IS - 34 (2021) SP - 153 EP - 164 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Orzada, Stephan A1 - Johst, Sören A1 - Maderwald, Stefan A1 - Bitz, Andreas A1 - Solbach, Klaus A1 - Ladd, Mark E. T1 - Mitigation of B1(+) inhomogeneity on single-channel transmit systems with TIAMO JF - Magnetic Resonance in Medicine Y1 - 2013 U6 - https://doi.org/10.1002/mrm.24453 SN - 1522-2594 VL - 70 IS - 1 SP - 290 EP - 294 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Orzada, Stephan A1 - Ladd, Mark E. A1 - Bitz, Andreas T1 - A method to approximate maximum local SAR in multichannel transmit MR systems without transmit phase information JF - Magnetic Resonance in Medicine N2 - Purpose To calculate local specific absorption rate (SAR) correctly, both the amplitude and phase of the signal in each transmit channel have to be known. In this work, we propose a method to derive a conservative upper bound for the local SAR, with a reasonable safety margin without knowledge of the transmit phases of the channels. Methods The proposed method uses virtual observation points (VOPs). Correction factors are calculated for each set of VOPs that prevent underestimation of local SAR when the VOPs are applied with the correct amplitudes but fixed phases. Results The proposed method proved to be superior to the worst-case calculation based on the maximum eigenvalue of the VOPs. The mean overestimation for six coil setups could be reduced, whereas no underestimation of the maximum local SAR occurred. In the best investigated case, the overestimation could be reduced from a factor of 3.3 to a factor of 1.7. Conclusion The upper bound for the local SAR calculated with the proposed method allows a fast estimation of the local SAR based on power measurements in the transmit channels and facilitates SAR monitoring in systems that do not have the capability to monitor transmit phases Y1 - 2016 U6 - https://doi.org/10.1002/mrm.26398 SN - 1522-2594 VL - 78 IS - 2 SP - 805 EP - 811 PB - International Society for Magnetic Resonance in Medicine ER - TY - JOUR A1 - Orzada, Stephan A1 - Maderwald, Stefan A1 - Poser, Benedikt Andreas A1 - Bitz, Andreas A1 - Quick, Harald H. A1 - Ladd, Mark E. T1 - RF excitation using time interleaved acquisition of modes (TIAMO) to address B1 inhomogeneity in high-field MRI JF - Magnetic Resonance in Medicine N2 - As the field strength and, therefore, the operational frequency in MRI is increased, the wavelength approaches the size of the human head/body, resulting in wave effects, which cause signal decreases and dropouts. Several multichannel approaches have been proposed to try to tackle these problems, including RF shimming, where each element in an array is driven by its own amplifier and modulated with a certain (constant) amplitude and phase relative to the other elements, and Transmit SENSE, where spatially tailored RF pulses are used. In this article, a relatively inexpensive and easy to use imaging scheme for 7 Tesla imaging is proposed to mitigate signal voids due to B1 field inhomogeneity. Two time-interleaved images are acquired using a different excitation mode for each. By forming virtual receive elements, both images are reconstructed together using GRAPPA to achieve a more homogeneous image, with only small SNR and SAR penalty in head and body imaging at 7 Tesla. Y1 - 2010 U6 - https://doi.org/10.1002/mrm.22527 SN - 1522-2594 VL - 64 IS - 2 SP - 327 EP - 333 PB - Wiley-Liss CY - New York ER - TY - JOUR A1 - Orzada, Stephan A1 - Solbach, Klaus A1 - Gratz, Marcel A1 - Brunheim, Sascha A1 - Fiedler, Thomas M. A1 - Johst, Sören A1 - Bitz, Andreas A1 - Shooshtary, Samaneh A1 - Abuelhaija, Ashraf A1 - Voelker, Maximilian N. A1 - Rietsch, Stefan H. G. A1 - Kraff, Oliver A1 - Maderwald, Stefan A1 - Flöser, Martina A1 - Oehmingen, Mark A1 - Quick, Harald H. A1 - Ladd, Mark E. T1 - A 32-channel parallel transmit system add-on for 7T MRI JF - Plos one Y1 - 2019 U6 - https://doi.org/10.1371/journal.pone.0222452 ER -