TY - CHAP A1 - Becker, Tim A1 - Bragard, Michael T1 - Low-Voltage DC Training Lab for Electric Drives - Optimizing the Balancing Act Between High Student Throughput and Individual Learning Speed T2 - 2024 IEEE Global Engineering Education Conference (EDUCON) N2 - After a brief introduction of conventional laboratory structures, this work focuses on an innovative and universal approach for a setup of a training laboratory for electric machines and drive systems. The novel approach employs a central 48 V DC bus, which forms the backbone of the structure. Several sets of DC machine, asynchronous machine and synchronous machine are connected to this bus. The advantages of the novel system structure are manifold, both from a didactic and a technical point of view: Student groups can work on their own performance level in a highly parallelized and at the same time individualized way. Additional training setups (similar or different) can easily be added. Only the total power dissipation has to be provided, i.e. the DC bus balances the power flow between the student groups. Comparative results of course evaluations of several cohorts of students are shown. KW - Synchronous machines KW - Power dissipation KW - Throughput KW - Low voltage KW - DC machines KW - Manifolds KW - Training Y1 - 2024 U6 - https://doi.org/10.1109/EDUCON60312.2024.10578902 SN - 2165-9559 SN - 2165-9567 (eISSN) N1 - 2024 IEEE Global Engineering Education Conference (EDUCON), 08-11 May 2024, Kos Island, Greece PB - IEEE CY - New York, NY ER - TY - JOUR A1 - Fiedler, Thomas M. A1 - Orzada, Stephan A1 - Flöser, Martina A1 - Rietsch, Stefan H. G. A1 - Quick, Harald H. A1 - Ladd, Mark E. A1 - Bitz, Andreas T1 - Performance analysis of integrated RF microstrip transmit antenna arrays with high channel count for body imaging at 7 T JF - NMR in Biomedicine N2 - The aim of the current study was to investigate the performance of integrated RF transmit arrays with high channel count consisting of meander microstrip antennas for body imaging at 7 T and to optimize the position and number of transmit ele- ments. RF simulations using multiring antenna arrays placed behind the bore liner were performed for realistic exposure conditions for body imaging. Simulations were performed for arrays with as few as eight elements and for arrays with high channel counts of up to 48 elements. The B1+ field was evaluated regarding the degrees of freedom for RF shimming in the abdomen. Worst-case specific absorption rate (SARwc ), SAR overestimation in the matrix compression, the number of virtual obser- vation points (VOPs) and SAR efficiency were evaluated. Constrained RF shimming was performed in differently oriented regions of interest in the body, and the devia- tion from a target B1+ field was evaluated. Results show that integrated multiring arrays are able to generate homogeneous B1+ field distributions for large FOVs, espe- cially for coronal/sagittal slices, and thus enable body imaging at 7 T with a clinical workflow; however, a low duty cycle or a high SAR is required to achieve homoge- neous B1+ distributions and to exploit the full potential. In conclusion, integrated arrays allow for high element counts that have high degrees of freedom for the pulse optimization but also produce high SARwc , which reduces the SAR accuracy in the VOP compression for low-SAR protocols, leading to a potential reduction in array performance. Smaller SAR overestimations can increase SAR accuracy, but lead to a high number of VOPs, which increases the computational cost for VOP evaluation and makes online SAR monitoring or pulse optimization challenging. Arrays with interleaved rings showed the best results in the study. KW - body imaging at UHF MRI KW - integrated transmit coil arrays KW - VOP compression Y1 - 2021 U6 - https://doi.org/10.1002/nbm.4515 SN - 0952-3480 (ISSN) SN - 1099-1492 (eISSN) VL - 34 IS - 7 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Frauenrath, Tobias A1 - Hezel, Fabian A1 - Renz, Wolfgang A1 - de Geyer d'Orth, Thibaut A1 - Dieringer, Matthias A1 - von Knobelsdorf-Brenkenhoff, Florian A1 - Prothmann, Marcel A1 - Schulz-Menger, Jeanette A1 - Niendorf, Thoralf T1 - Acoustic cardiac triggering: a practical solution for synchronization and gating of cardiovascular magnetic resonance at 7 Tesla JF - Journal of Cardiovascular Magnetic Resonance N2 - Background To demonstrate the applicability of acoustic cardiac triggering (ACT) for imaging of the heart at ultrahigh magnetic fields (7.0 T) by comparing phonocardiogram, conventional vector electrocardiogram (ECG) and traditional pulse oximetry (POX) triggered 2D CINE acquisitions together with (i) a qualitative image quality analysis, (ii) an assessment of the left ventricular function parameter and (iii) an examination of trigger reliability and trigger detection variance derived from the signal waveforms. Results ECG was susceptible to severe distortions at 7.0 T. POX and ACT provided waveforms free of interferences from electromagnetic fields or from magneto-hydrodynamic effects. Frequent R-wave mis-registration occurred in ECG-triggered acquisitions with a failure rate of up to 30% resulting in cardiac motion induced artifacts. ACT and POX triggering produced images free of cardiac motion artefacts. ECG showed a severe jitter in the R-wave detection. POX also showed a trigger jitter of approximately Δt = 72 ms which is equivalent to two cardiac phases. ACT showed a jitter of approximately Δt = 5 ms only. ECG waveforms revealed a standard deviation for the cardiac trigger offset larger than that observed for ACT or POX waveforms. Image quality assessment showed that ACT substantially improved image quality as compared to ECG (image quality score at end-diastole: ECG = 1.7 ± 0.5, ACT = 2.4 ± 0.5, p = 0.04) while the comparison between ECG vs. POX gated acquisitions showed no significant differences in image quality (image quality score: ECG = 1.7 ± 0.5, POX = 2.0 ± 0.5, p = 0.34). Conclusions The applicability of acoustic triggering for cardiac CINE imaging at 7.0 T was demonstrated. ACT's trigger reliability and fidelity are superior to that of ECG and POX. ACT promises to be beneficial for cardiovascular magnetic resonance at ultra-high field strengths including 7.0 T. KW - Interval Time Series KW - Image Quality Score KW - Image Quality Assessment KW - Sound Pressure Level KW - Cardiovascular Magnetic Resonance Y1 - 2010 U6 - https://doi.org/10.1186/1532-429X-12-67 SN - 1532-429X VL - 12 IS - 1 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kob, Malte A1 - Frauenrath, Tobias T1 - A system for parallel measurement of glottis opening and larynx position JF - Biomedical Signal Processing and Control N2 - The simultaneous assessment of glottal dynamics and larynx position can be beneficial for the diagnosis of disordered voice or speech production and swallowing. Up to now, methods either concentrate on assessment of the glottis opening using optical, acoustical or electrical (electroglottography, EGG) methods, or on visualisation of the larynx position using ultrasound, computer tomography or magnetic resonance imaging techniques. The method presented here makes use of a time-multiplex measurement approach of space-resolved transfer impedances through the larynx. The fast sequence of measurements allows a quasi simultaneous assessment of both larynx position and EGG signal using up to 32 transmit–receive signal paths. The system assesses the dynamic opening status of the glottis as well as the vertical and back/forward motion of the larynx. Two electrode-arrays are used for the measurement of the electrical transfer impedance through the neck in different directions. From the acquired data the global and individual conductivity is calculated as well as a 2D point spatial representation of the minimum impedance. The position information is shown together with classical EGG signals allowing a synchronous visual assessment of glottal area and larynx position. A first application to singing voice analysis is presented that indicate a high potential of the method for use as a non-invasive tool in the diagnosis of voice, speech, and swallowing disorders. KW - EGG KW - Transfer impedance KW - Tomography KW - Larynx position KW - Voice assessment Y1 - 2009 U6 - https://doi.org/10.1016/j.bspc.2009.03.004 SN - 1746-8108 VL - 4 IS - 3 SP - 221 EP - 228 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Heinrichs, Uwe A1 - Utting, Jane F. A1 - Frauenrath, Tobias A1 - Hezel, Fabian A1 - Krombach, Gabriele A. A1 - Hodenius, Michael A. J. A1 - Kozerke, Sebastian A1 - Niendorf, Thoralf T1 - Myocardial T2 mapping free of distortion using susceptibility-weighted fast spin-echo imaging: A feasibility study at 1.5 T and 3.0 T JF - Magnetic Resonance in Medicine N2 - This study demonstrates the feasibility of applying free-breathing, cardiac-gated, susceptibility-weighted fast spin-echo imaging together with black blood preparation and navigator-gated respiratory motion compensation for anatomically accurate T₂ mapping of the heart. First, T₂ maps are presented for oil phantoms without and with respiratory motion emulation (T₂ = (22.1 ± 1.7) ms at 1.5 T and T₂ = (22.65 ± 0.89) ms at 3.0 T). T₂ relaxometry of a ferrofluid revealed relaxivities of R2 = (477.9 ± 17) mM⁻¹s⁻¹ and R2 = (449.6 ± 13) mM⁻¹s⁻¹ for UFLARE and multiecho gradient-echo imaging at 1.5 T. For inferoseptal myocardial regions mean T₂ values of 29.9 ± 6.6 ms (1.5 T) and 22.3 ± 4.8 ms (3.0 T) were estimated. For posterior myocardial areas close to the vena cava T₂-values of 24.0 ± 6.4 ms (1.5 T) and 15.4 ± 1.8 ms (3.0 T) were observed. The merits and limitations of the proposed approach are discussed and its implications for cardiac and vascular T₂-mapping are considered. Y1 - 2009 U6 - https://doi.org/10.1002/mrm.22054 SN - 1522-2594 VL - 62 IS - 3 SP - 822 EP - 828 PB - Wiley-Liss CY - New York ER - TY - JOUR A1 - Frauenrath, Tobias A1 - Niendorf, Thoralf A1 - Kob, Malte T1 - Acoustic method for synchronization of Magnetic Resonance Imaging (MRI) JF - Acta Acustica N2 - Magnetic Resonance Imaging (MRI) of moving organs requires synchronization with physiological motion or flow, which dictate the viable window for data acquisition. To meet this challenge, this study proposes an acoustic gating device (ACG) that employs acquisition and processing of acoustic signals for synchronization while providing MRI compatibility, immunity to interferences with electro-magnetic and acoustic fields and suitability for MRI at high magnetic field strengths. The applicability and robustness of the acoustic gating approach is examined in a pilot study, where it substitutes conventional ECG-gating for cardiovascular MR. The merits and limitations of the ACG approach are discussed. Implications for MR imaging in the presence of physiological motion are considered including synchronization with other structure- or motion borne sounds. Y1 - 2008 U6 - https://doi.org/10.3813/AAA.918017 SN - 1861-9959 VL - 94 IS - 1 SP - 148 EP - 155 PB - Hirzel CY - Stuttgart ER - TY - JOUR A1 - von Knobelsdorf-Brenkenhoff, Florian A1 - Frauenrath, Tobias A1 - Prothmann, Marcel A1 - Dieringer, Matthias A. A1 - Hezel, Fabian A1 - Renz, Wolfgang A1 - Kretschel, Kerstin A1 - Niendorf, Thoralf A1 - Schulz-Menger, Jeanette T1 - Cardiac chamber quantification using magnetic resonance imaging at 7 Tesla—a pilot study N2 - Objectives Interest in cardiovascular magnetic resonance (CMR) at 7 T is motivated by the expected increase in spatial and temporal resolution, but the method is technically challenging. We examined the feasibility of cardiac chamber quantification at 7 T. Methods A stack of short axes covering the left ventricle was obtained in nine healthy male volunteers. At 1.5 T, steady-state free precession (SSFP) and fast gradient echo (FGRE) cine imaging with 7 mm slice thickness (STH) were used. At 7 T, FGRE with 7 mm and 4 mm STH were applied. End-diastolic volume, end-systolic volume, ejection fraction and mass were calculated. Results All 7 T examinations provided excellent blood/myocardium contrast for all slice directions. No significant difference was found regarding ejection fraction and cardiac volumes between SSFP at 1.5 T and FGRE at 7 T, while volumes obtained from FGRE at 1.5 T were underestimated. Cardiac mass derived from FGRE at 1.5 and 7 T was larger than obtained from SSFP at 1.5 T. Agreement of volumes and mass between SSFP at 1.5 T and FGRE improved for FGRE at 7 T when combined with an STH reduction to 4 mm. Conclusions This pilot study demonstrates that cardiac chamber quantification at 7 T using FGRE is feasible and agrees closely with SSFP at 1.5 T. Y1 - 2010 U6 - https://doi.org/10.1007/s00330-010-1888-2 SN - 0938-7994 VL - 20 SP - 2844 EP - 2852 PB - Springer CY - Berlin, Heidelberg ER - TY - CHAP A1 - Vladova, Gergana A1 - Ullrich, André A1 - Sultanow, Eldar A1 - Tobolla, Marinho A1 - Sebrak, Sebastian A1 - Czarnecki, Christian A1 - Brockmann, Carsten T1 - Visual analytics for knowledge management T2 - INFORMATIK 2023 - Designing Futures: Zukünfte gestalten N2 - The management of knowledge in organizations considers both established long-term processes and cooperation in agile project teams. Since knowledge can be both tacit and explicit, its transfer from the individual to the organizational knowledge base poses a challenge in organizations. This challenge increases when the fluctuation of knowledge carriers is exceptionally high. Especially in large projects in which external consultants are involved, there is a risk that critical, company-relevant knowledge generated in the project will leave the company with the external knowledge carrier and thus be lost. In this paper, we show the advantages of an early warning system for knowledge management to avoid this loss. In particular, the potential of visual analytics in the context of knowledge management systems is presented and discussed. We present a project for the development of a business-critical software system and discuss the first implementations and results. Y1 - 2023 SN - 978-3-88579-731-9 U6 - https://doi.org/10.18420/inf2023_187 SN - 1617-5468 N1 - INFORMATIK 2023, 26. - 29. September 2023, Berlin SP - 1851 EP - 1870 PB - GI - Gesellschaft für Informatik CY - Bonn ER - TY - CHAP A1 - Schult, Prince Garcia A1 - Losse, Ann-Kathrin A1 - Czarnecki, Christian A1 - Sultanow, Eldar T1 - Proposing a Framework to address the Sustainable Development Goals T2 - EnviroInfo 2023 N2 - Reducing poverty, protecting the planet, and improving life on earth for everyone are the essential goals of the "2030 Agenda for Sustainable Development"committed by the United Nations (UN). Achieving those goals will require technological innovation as well as their implementation in almost all areas of our business and day-to-day life. This paper proposes a high-level framework that collects and structures different uses cases addressing the goals defined by the UN. Hence, it contributes to the discussion by proposing technical innovations that can be used to achieve those goals. As an example, the goal "Climate Actionïs discussed in detail by describing use cases related to tackling biodiversity loss in order to conservate ecosystems. Y1 - 2023 SN - 978-3-88579-736-4 U6 - https://doi.org/10.18420/env2023-022 SN - 1617-5468 N1 - EnviroInfo 2023, 11. - 23. October 2023, Garching, Germany SP - 243 EP - 249 PB - GI - Gesellschaft für Informatik CY - Bonn ER - TY - JOUR A1 - Droop, Philipp A1 - Chen, Shaohuang A1 - Radford, Melissa J. A1 - Paulßen, Elisabeth A1 - Gates, Byron D. A1 - Reilly, Raymond M. A1 - Radchenko, Valery A1 - Hoehr, Cornelia T1 - Synthesis of 197m/gHg labelled gold nanoparticles for targeted radionuclide therapy JF - Radiochimica Acta N2 - Meitner-Auger-electron emitters have a promising potential for targeted radionuclide therapy of cancer because of their short range and the high linear energy transfer of Meitner-Auger-electrons (MAE). One promising MAE candidate is 197m/gHg with its half-life of 23.8 h and 64.1 h, respectively, and high MAE yield. Gold nanoparticles (AuNPs) that are labelled with 197m/gHg could be a helpful tool for radiation treatment of glioblastoma multiforme when infused into the surgical cavity after resection to prevent recurrence. To produce such AuNPs, 197m/gHg was embedded into pristine AuNPs. Two different syntheses were tested starting from irradiated gold containing trace amounts of 197m/gHg. When sodium citrate was used as reducing agent, no 197m/gHg labelled AuNPs were formed, but with tannic acid, 197m/gHg labeled AuNPs were produced. The method was optimized by neutralizing the pH (pH = 7) of the Au/197m/gHg solution, which led to labelled AuNPs with a size of 12.3 ± 2.0 nm as measured by transmission electron microscopy. The labelled AuNPs had a concentration of 50 μg (gold)/mL with an activity of 151 ± 93 kBq/mL (197gHg, time corrected to the end of bombardment). KW - 197m/gHg KW - Gold nanoparticle (AuNP) KW - Meitner-Auger-electron (MAE) KW - Targeted radionuclide therapy (TRT) Y1 - 2023 U6 - https://doi.org/10.1515/ract-2023-0144 SN - 2193-3405 VL - 111 IS - 10 SP - 773 EP - 779 PB - De Gruyter CY - Berlin [u.a.] ER -