@article{FrauenrathNiendorfKob2008, author = {Frauenrath, Tobias and Niendorf, Thoralf and Kob, Malte}, title = {Acoustic method for synchronization of Magnetic Resonance Imaging (MRI)}, series = {Acta Acustica}, volume = {94}, journal = {Acta Acustica}, number = {1}, publisher = {Hirzel}, address = {Stuttgart}, issn = {1861-9959}, doi = {10.3813/AAA.918017}, pages = {148 -- 155}, year = {2008}, abstract = {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.}, language = {en} } @article{MaurerRiekeSchemmetal.2023, author = {Maurer, Florian and Rieke, Christian and Schemm, Ralf and Stollenwerk, Dominik}, title = {Analysis of an urban grid with high photovoltaic and e-mobility penetration}, series = {Energies}, volume = {16}, journal = {Energies}, number = {8}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {10.3390/en16083380}, pages = {18 Seiten}, year = {2023}, abstract = {This study analyses the expected utilization of an urban distribution grid under high penetration of photovoltaic and e-mobility with charging infrastructure on a residential level. The grid utilization and the corresponding power flow are evaluated, while varying the control strategies and photovoltaic installed capacity in different scenarios. Four scenarios are used to analyze the impact of e-mobility. The individual mobility demand is modelled based on the largest German studies on mobility "Mobilit{\"a}t in Deutschland", which is carried out every 5 years. To estimate the ramp-up of photovoltaic generation, a potential analysis of the roof surfaces in the supply area is carried out via an evaluation of an open solar potential study. The photovoltaic feed-in time series is derived individually for each installed system in a resolution of 15 min. The residential consumption is estimated using historical smart meter data, which are collected in London between 2012 and 2014. For a realistic charging demand, each residential household decides daily on the state of charge if their vehicle requires to be charged. The resulting charging time series depends on the underlying behavior scenario. Market prices and mobility demand are therefore used as scenario input parameters for a utility function based on the current state of charge to model individual behavior. The aggregated electricity demand is the starting point of the power flow calculation. The evaluation is carried out for an urban region with approximately 3100 residents. The analysis shows that increased penetration of photovoltaics combined with a flexible and adaptive charging strategy can maximize PV usage and reduce the need for congestion-related intervention by the grid operator by reducing the amount of kWh charged from the grid by 30\% which reduces the average price of a charged kWh by 35\% to 14 ct/kWh from 21.8 ct/kWh without PV optimization. The resulting grid congestions are managed by implementing an intelligent price or control signal. The analysis took place using data from a real German grid with 10 subgrids. The entire software can be adapted for the analysis of different distribution grids and is publicly available as an open-source software library on GitHub.}, language = {en} } @article{ClaerFerreinSchiffer2019, author = {Claer, Mario and Ferrein, Alexander and Schiffer, Stefan}, title = {Calibration of a Rotating or Revolving Platform with a LiDAR Sensor}, series = {Applied Sciences}, volume = {Volume 9}, journal = {Applied Sciences}, number = {issue 11, 2238}, publisher = {MDPI}, address = {Basel}, issn = {2076-3417}, doi = {10.3390/app9112238}, pages = {18 Seiten}, year = {2019}, language = {en} } @article{KahmannRauschPluemeretal.2022, author = {Kahmann, Stephanie L. and Rausch, Valentin and Pl{\"u}mer, Jonathan and M{\"u}ller, Lars P. and Pieper, Martin and Wegmann, Kilian}, title = {The automized fracture edge detection and generation of three-dimensional fracture probability heat maps}, series = {Medical Engineering \& Physics}, volume = {2022}, journal = {Medical Engineering \& Physics}, number = {110}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1350-4533}, pages = {7 Seiten}, year = {2022}, abstract = {With proven impact of statistical fracture analysis on fracture classifications, it is desirable to minimize the manual work and to maximize repeatability of this approach. We address this with an algorithm that reduces the manual effort to segmentation, fragment identification and reduction. The fracture edge detection and heat map generation are performed automatically. With the same input, the algorithm always delivers the same output. The tool transforms one intact template consecutively onto each fractured specimen by linear least square optimization, detects the fragment edges in the template and then superimposes them to generate a fracture probability heat map. We hypothesized that the algorithm runs faster than the manual evaluation and with low (< 5 mm) deviation. We tested the hypothesis in 10 fractured proximal humeri and found that it performs with good accuracy (2.5 mm ± 2.4 mm averaged Euclidean distance) and speed (23 times faster). When applied to a distal humerus, a tibia plateau, and a scaphoid fracture, the run times were low (1-2 min), and the detected edges correct by visual judgement. In the geometrically complex acetabulum, at a run time of 78 min some outliers were considered acceptable. An automatically generated fracture probability heat map based on 50 proximal humerus fractures matches the areas of high risk of fracture reported in medical literature. Such automation of the fracture analysis method is advantageous and could be extended to reduce the manual effort even further.}, language = {en} } @article{EngelmannSimsekShalabyetal.2024, author = {Engelmann, Ulrich M. and Simsek, Beril and Shalaby, Ahmed and Krause, Hans-Joachim}, title = {Key contributors to signal generation in frequency mixing magnetic detection (FMMD): an in silico study}, series = {Sensors}, volume = {24}, journal = {Sensors}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s24061945}, pages = {Artikel 1945}, year = {2024}, abstract = {Frequency mixing magnetic detection (FMMD) is a sensitive and selective technique to detect magnetic nanoparticles (MNPs) serving as probes for binding biological targets. Its principle relies on the nonlinear magnetic relaxation dynamics of a particle ensemble interacting with a dual frequency external magnetic field. In order to increase its sensitivity, lower its limit of detection and overall improve its applicability in biosensing, matching combinations of external field parameters and internal particle properties are being sought to advance FMMD. In this study, we systematically probe the aforementioned interaction with coupled N{\´e}el-Brownian dynamic relaxation simulations to examine how key MNP properties as well as applied field parameters affect the frequency mixing signal generation. It is found that the core size of MNPs dominates their nonlinear magnetic response, with the strongest contributions from the largest particles. The drive field amplitude dominates the shape of the field-dependent response, whereas effective anisotropy and hydrodynamic size of the particles only weakly influence the signal generation in FMMD. For tailoring the MNP properties and parameters of the setup towards optimal FMMD signal generation, our findings suggest choosing large particles of core sizes dc > 25 nm nm with narrow size distributions (σ < 0.1) to minimize the required drive field amplitude. This allows potential improvements of FMMD as a stand-alone application, as well as advances in magnetic particle imaging, hyperthermia and magnetic immunoassays.}, language = {en} } @article{HorbachStaat2018, author = {Horbach, Andreas and Staat, Manfred}, title = {Optical strain measurement for the modeling of surgical meshes and their porosity}, series = {Current Directions in Biomedical Engineering}, volume = {Band 4}, journal = {Current Directions in Biomedical Engineering}, number = {1}, publisher = {De Gruyter}, address = {Berlin}, issn = {2364-5504}, doi = {10.1515/cdbme-2018-0045}, pages = {181 -- 184}, year = {2018}, abstract = {The porosity of surgical meshes makes them flexible for large elastic deformation and establishes the healing conditions of good tissue in growth. The biomechanic modeling of orthotropic and compressible materials requires new materials models and simulstaneoaus fit of deformation in the load direction as well as trannsversely to to load. This nonlinear modeling can be achieved by an optical deformation measurement. At the same time the full field deformation measurement allows the dermination of the change of porosity with deformation. Also the socalled effective porosity, which has been defined to asses the tisssue interatcion with the mesh implants, can be determined from the global deformation of the surgical meshes.}, language = {en} } @article{SchoeningArzdorfMulchandanietal.2003, author = {Sch{\"o}ning, Michael Josef and Arzdorf, Michael and Mulchandani, P. and Chen, W. and Mulchandani, A.}, title = {Towards a capacitive enzyme sensor for direct determination of organophosphorus pesticides: Fundamentals studies and aspects of development}, series = {Sensors. 3 (2003), H. 6}, journal = {Sensors. 3 (2003), H. 6}, isbn = {1424-8220}, pages = {119 -- 127}, year = {2003}, language = {en} } @article{SchoeningArzdorfMulchandanietal.2003, author = {Sch{\"o}ning, Michael Josef and Arzdorf, Michael and Mulchandani, P. and Chen, W. and Mulchandani, A.}, title = {A capacitive field-effect sensor for the direct determination of organophosphorus pesticides}, series = {Sensors and Actuators B. 91 (2003), H. 1-3}, journal = {Sensors and Actuators B. 91 (2003), H. 1-3}, isbn = {0925-4005}, pages = {92 -- 97}, year = {2003}, language = {en} } @article{MikuckiSchulerDigeletal.2023, author = {Mikucki, Jill Ann and Schuler, C. G. and Digel, Ilya and Kowalski, Julia and Tuttle, M. J. and Chua, Michelle and Davis, R. and Purcell, Alicia and Ghosh, D. and Francke, G. and Feldmann, M. and Espe, C. and Heinen, Dirk and Dachwald, Bernd and Clemens, Joachim and Lyons, W. B. and Tulaczyk, S.}, title = {Field-Based planetary protection operations for melt probes: validation of clean access into the blood falls, antarctica, englacial ecosystem}, series = {Astrobiology}, volume = {23}, journal = {Astrobiology}, number = {11}, publisher = {Liebert}, address = {New York, NY}, issn = {1557-8070 (online)}, doi = {10.1089/ast.2021.0102}, pages = {1165 -- 1178}, year = {2023}, abstract = {Subglacial environments on Earth offer important analogs to Ocean World targets in our solar system. These unique microbial ecosystems remain understudied due to the challenges of access through thick glacial ice (tens to hundreds of meters). Additionally, sub-ice collections must be conducted in a clean manner to ensure sample integrity for downstream microbiological and geochemical analyses. We describe the field-based cleaning of a melt probe that was used to collect brine samples from within a glacier conduit at Blood Falls, Antarctica, for geomicrobiological studies. We used a thermoelectric melting probe called the IceMole that was designed to be minimally invasive in that the logistical requirements in support of drilling operations were small and the probe could be cleaned, even in a remote field setting, so as to minimize potential contamination. In our study, the exterior bioburden on the IceMole was reduced to levels measured in most clean rooms, and below that of the ice surrounding our sampling target. Potential microbial contaminants were identified during the cleaning process; however, very few were detected in the final englacial sample collected with the IceMole and were present in extremely low abundances (∼0.063\% of 16S rRNA gene amplicon sequences). This cleaning protocol can help minimize contamination when working in remote field locations, support microbiological sampling of terrestrial subglacial environments using melting probes, and help inform planetary protection challenges for Ocean World analog mission concepts.}, language = {en} } @article{ZiemonsAuffrayBarbieretal.2005, author = {Ziemons, Karl and Auffray, Etiennette and Barbier, R. and Brandenburg, G. and Bruyndonckx, P.}, title = {The ClearPET™ project: Development of a 2nd generation high-performance small animal PET scanner}, series = {Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, volume = {537}, journal = {Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, number = {1-2}, issn = {0168-9002}, pages = {307 -- 311}, year = {2005}, abstract = {Second generation high-performance PET scanners, called ClearPET™1, have been developed by working groups of the Crystal Clear Collaboration (CCC). High sensitivity and high spatial resolution for the ClearPET camera is achieved by using a phoswich arrangement combining two different types of lutetium-based scintillator materials: LSO from CTI and LuYAP:Ce from the CCC (ISTC project). In a first ClearPET prototype, phoswich arrangements of 8×8 crystals of 2×2×10 mm3 are coupled to multi-channel photomultiplier tubes (Hamamatsu R7600). A unit of four PMTs arranged in-line represents one of 20 sectors of the ring design. The opening diameter of the ring is 120 mm, the axial detector length is 110 mm.The PMT pulses are digitized by free-running ADCs and digital data processing determines the gamma energy, the phoswich layer and even the exact pulse starting time, which is subsequently used for coincidence detection. The gantry allows rotation of the detector modules around the field of view. Preliminary data shows a correct identification of the crystal layer about (98±1)\%. Typically the energy resolution is (23.3±0.5)\% for the luyap layer and (15.4±0.4)\% for the lso layer. early studies showed the timing resolution of 2 ns FWHM and 4.8 ns FWTM. the intrinsic spatial resolution ranges from 1.37 mm to 1.61 mm full-width of half-maximum (FWHM) with a mean of 1.48 mm FWHM. further improvements in image and energy resolution are expected when the system geometry is fully modeled.}, language = {en} }