@article{SchoeningSchrothLuethetal.2001, author = {Sch{\"o}ning, Michael Josef and Schroth, Peter and L{\"u}th, Hans and Hummel, Hans E. and Sch{\"u}tz, Stefan}, title = {Insect chemoreceptors coupled to silicon transistors as innovative biosensors}, series = {Proceedings of SPIE. 4205 (2001)}, journal = {Proceedings of SPIE. 4205 (2001)}, pages = {152 -- 162}, year = {2001}, language = {en} } @article{PaschmannSchmidt2001, author = {Paschmann, Hans and Schmidt, Stefan}, title = {Mechanische Eigenschaften von Glasfasermixbeton. Wie viel Fasern braucht Beton? / Schmidt, Stefan; Paschmann, Hans}, series = {BFT Betonwerk + Fertigteil-Technik. 67 (2001), H. 10}, journal = {BFT Betonwerk + Fertigteil-Technik. 67 (2001), H. 10}, isbn = {0373-4331}, pages = {64 -- 75}, year = {2001}, language = {de} } @article{WagnerMarisAckermannetal.2007, author = {Wagner, Torsten and Maris, Rob J. and Ackermann, Hans-Josef and Otto, Ralph and Beging, Stefan and Poghossian, Arshak and Sch{\"o}ning, Michael Josef}, title = {Handheld measurement device for field-effect sensor structures: Practical evaluation and limitations}, series = {Sensors and Actuators B: Chemical . 127 (2007), H. 1}, journal = {Sensors and Actuators B: Chemical . 127 (2007), H. 1}, isbn = {0925-4005}, pages = {217 -- 223}, year = {2007}, language = {en} } @article{TersteggeWeberHerzogetal.1996, author = {Terstegge, Andreas and Weber, Stefan and Herzog, H. and M{\"u}ller-G{\"a}rtner, Hans- W. [u.a.]}, title = {High resolution and better quantification by tube of responsemodelling in 3D PET reconstruction}, series = {Selected papers from the 1996 Nuclear Science Symposium : Marriott Hotel, Anaheim, California, November 3rd - November 9th, 1996}, journal = {Selected papers from the 1996 Nuclear Science Symposium : Marriott Hotel, Anaheim, California, November 3rd - November 9th, 1996}, publisher = {Inst. of Electrical and Electronic Engineers}, address = {New York}, pages = {1603 -- 1607}, year = {1996}, language = {en} } @article{TersteggeWeberHerzogetal.1997, author = {Terstegge, Andreas and Weber, Stefan and Herzog, H. and M{\"u}ller-G{\"a}rtner, Hans- W. [u.a.]}, title = {Entwicklung eines Positronen-Emissions-Tomographen mit hoher Ortsaufl{\"o}sung f{\"u}r Labortiere}, series = {Bildverarbeitung f{\"u}r die Medizin : Algorithmen - Systeme - Anwendungen ; proceedings des Aachener Workshops am 8. und 9. November 1996 / Institut f{\"u}r Medizinische Informatik und Biometrie der RWTH Aachen. Hrsg. von Thomas Lehmann ...}, journal = {Bildverarbeitung f{\"u}r die Medizin : Algorithmen - Systeme - Anwendungen ; proceedings des Aachener Workshops am 8. und 9. November 1996 / Institut f{\"u}r Medizinische Informatik und Biometrie der RWTH Aachen. Hrsg. von Thomas Lehmann ...}, publisher = {Verl. der Augustinus-Buchhandlung}, address = {Aachen}, isbn = {3-86073-519-5}, pages = {267 -- 272}, year = {1997}, language = {de} } @article{FrankBuchwaldPennekampetal.2009, author = {Frank, T. and Buchwald, D. and Pennekamp, W. and Reber, D. and Sponagel, Stefan and Laszkovics, A. and Weber, Hans-Joachim}, title = {R{\"o}ntgenologische Untersuchung der Str{\"o}mungseigenschaften funktioneller Komponenten der Herz-Lungen-Maschine}, series = {Kardiotechnik. 18 (2009), H. 2}, journal = {Kardiotechnik. 18 (2009), H. 2}, isbn = {0941-2670}, pages = {31 -- 35}, year = {2009}, language = {de} } @article{MausHoefkenSchuba2011, author = {Maus, Stefan and H{\"o}fken, Hans-Wilhelm and Schuba, Marko}, title = {Forensic Analysis of Geodata in Android Smartphones}, pages = {1 -- 11}, year = {2011}, language = {en} } @article{GaribaldiBegingCaneseetal.2017, author = {Garibaldi, F. and Beging, Stefan and Canese, R. and Carpinelli, G. and Clinthorne, N. and Colilli, S. and Cosentino, L. and Finocchiaro, P. and Giuliani, F. and Gricia, M. and Lucentini, M. and Majewski, S. and Monno, E. and Musico, P. and Santavenere, F. and T{\"o}dter, J. and Wegener, Hans-Peter and Ziemons, Karl}, title = {A novel TOF-PET MRI detector for diagnosis and follow up of the prostate cancer}, series = {European Physical Journal Plus}, volume = {132}, journal = {European Physical Journal Plus}, number = {9}, publisher = {Springer}, address = {Berlin}, issn = {2190-5444}, doi = {10.1140/epjp/i2017-11662-x}, year = {2017}, language = {en} } @article{HansScheerRiedletal.2004, author = {Hans, Stefan and Scheer, Nico and Riedl, Iris and Weiz{\"a}cker, Elisabeth von and Blader, Patrick and Campos-Ortega, Jos{\´e} A.}, title = {her3, a zebrafish member of the hairy-E(spl) family, is repressed by Notch signalling}, series = {Development}, volume = {131}, journal = {Development}, number = {12}, issn = {1477-9129}, doi = {10.1242/dev.01167}, pages = {2957 -- 2969}, year = {2004}, language = {en} } @article{ScheerGrothHansetal.2001, author = {Scheer, Nico and Groth, Anne and Hans, Stefan and Campos-Ortega, Jos{\´e} A.}, title = {An instructive function for Notch in promoting gliogenesis in the zebrafish retina}, series = {Development}, volume = {128}, journal = {Development}, number = {7}, issn = {0950-1991}, pages = {1099 -- 1107}, year = {2001}, language = {en} } @article{PourshahidiAchtsnichtOffenhaeusseretal.2022, author = {Pourshahidi, Ali Mohammad and Achtsnicht, Stefan and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim}, title = {Frequency Mixing Magnetic Detection Setup Employing Permanent Ring Magnets as a Static Offset Field Source}, series = {Sensors}, volume = {22}, journal = {Sensors}, number = {22}, editor = {Offenh{\"a}usser, Andreas}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s22228776}, pages = {12 Seiten}, year = {2022}, abstract = {Frequency mixing magnetic detection (FMMD) has been explored for its applications in fields of magnetic biosensing, multiplex detection of magnetic nanoparticles (MNP) and the determination of core size distribution of MNP samples. Such applications rely on the application of a static offset magnetic field, which is generated traditionally with an electromagnet. Such a setup requires a current source, as well as passive or active cooling strategies, which directly sets a limitation based on the portability aspect that is desired for point of care (POC) monitoring applications. In this work, a measurement head is introduced that involves the utilization of two ring-shaped permanent magnets to generate a static offset magnetic field. A steel cylinder in the ring bores homogenizes the field. By variation of the distance between the ring magnets and of the thickness of the steel cylinder, the magnitude of the magnetic field at the sample position can be adjusted. Furthermore, the measurement setup is compared to the electromagnet offset module based on measured signals and temperature behavior.}, language = {en} } @article{PourshahidiAchtsnichtNambipareecheeetal.2021, author = {Pourshahidi, Ali Mohammad and Achtsnicht, Stefan and Nambipareechee, Mrinal Murali and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim}, title = {Multiplex detection of magnetic beads using offset field dependent frequency mixing magnetic detection}, series = {Sensors}, volume = {21}, journal = {Sensors}, number = {17}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s21175859}, pages = {16 Seiten}, year = {2021}, abstract = {Magnetic immunoassays employing Frequency Mixing Magnetic Detection (FMMD) have recently become increasingly popular for quantitative detection of various analytes. Simultaneous analysis of a sample for two or more targets is desirable in order to reduce the sample amount, save consumables, and save time. We show that different types of magnetic beads can be distinguished according to their frequency mixing response to a two-frequency magnetic excitation at different static magnetic offset fields. We recorded the offset field dependent FMMD response of two different particle types at frequencies ƒ₁ + n⋅ƒ₂, n = 1, 2, 3, 4 with ƒ₁ = 30.8 kHz and ƒ₂ = 63 Hz. Their signals were clearly distinguishable by the locations of the extremes and zeros of their responses. Binary mixtures of the two particle types were prepared with different mixing ratios. The mixture samples were analyzed by determining the best linear combination of the two pure constituents that best resembled the measured signals of the mixtures. Using a quadratic programming algorithm, the mixing ratios could be determined with an accuracy of greater than 14\%. If each particle type is functionalized with a different antibody, multiplex detection of two different analytes becomes feasible.}, language = {en} } @article{AchtsnichtPourshahidiOffenhaeusseretal.2019, author = {Achtsnicht, Stefan and Pourshahidi, Ali Mohammad and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim}, title = {Multiplex detection of different magnetic beads using frequency scanning in magnetic frequency mixing technique}, series = {Sensors}, volume = {19}, journal = {Sensors}, number = {11}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s19112599}, pages = {13 Seiten}, year = {2019}, abstract = {In modern bioanalytical methods, it is often desired to detect several targets in one sample within one measurement. Immunological methods including those that use superparamagnetic beads are an important group of techniques for these applications. The goal of this work is to investigate the feasibility of simultaneously detecting different superparamagnetic beads acting as markers using the magnetic frequency mixing technique. The frequency of the magnetic excitation field is scanned while the lower driving frequency is kept constant. Due to the particles' nonlinear magnetization, mixing frequencies are generated. To record their amplitude and phase information, a direct digitization of the pickup-coil's signal with subsequent Fast Fourier Transformation is performed. By synchronizing both magnetic beads using frequency scanning in magnetic frequency mixing technique magnetic fields, a stable phase information is gained. In this research, it is shown that the amplitude of the dominant mixing component is proportional to the amount of superparamagnetic beads inside a sample. Additionally, it is shown that the phase does not show this behaviour. Excitation frequency scans of different bead types were performed, showing different phases, without correlation to their diverse amplitudes. Two commercially available beads were selected and a determination of their amount in a mixture is performed as a demonstration for multiplex measurements.}, language = {en} } @article{AchtsnichtToedterNiehuesetal.2019, author = {Achtsnicht, Stefan and T{\"o}dter, Julia and Niehues, Julia and Tel{\"o}ken, Matthias and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim and Schr{\"o}per, Florian}, title = {3D printed modular immunofiltration columns for frequency mixing-based multiplex magnetic immunodetection}, series = {Sensors}, volume = {19}, journal = {Sensors}, number = {1}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s19010148}, pages = {15 Seiten}, year = {2019}, abstract = {For performing point-of-care molecular diagnostics, magnetic immunoassays constitute a promising alternative to established enzyme-linked immunosorbent assays (ELISA) because they are fast, robust and sensitive. Simultaneous detection of multiple biomolecular targets from one body fluid sample is desired. The aim of this work is to show that multiplex magnetic immunodetection based on magnetic frequency mixing by means of modular immunofiltration columns prepared for different targets is feasible. By calculations of the magnetic response signal, the required spacing between the modules was determined. Immunofiltration columns were manufactured by 3D printing and antibody immobilization was performed in a batch approach. It was shown experimentally that two different target molecules in a sample solution could be individually detected in a single assaying step with magnetic measurements of the corresponding immobilization filters. The arrangement order of the filters and of a negative control did not influence the results. Thus, a simple and reliable approach to multi-target magnetic immunodetection was demonstrated.}, language = {en} } @article{AchtsnichtSchoenenbornOffenhaeusseretal.2019, author = {Achtsnicht, Stefan and Sch{\"o}nenborn, Kristina and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim}, title = {Measurement of the magnetophoretic velocity of different superparamagnetic beads}, series = {Journal of Magnetism and Magnetic Materials}, volume = {477}, journal = {Journal of Magnetism and Magnetic Materials}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-8853}, doi = {10.1016/j.jmmm.2018.10.066}, pages = {244 -- 248}, year = {2019}, abstract = {The movement of magnetic beads due to a magnetic field gradient is of great interest in different application fields. In this report we present a technique based on a magnetic tweezers setup to measure the velocity factor of magnetically actuated individual superparamagnetic beads in a fluidic environment. Several beads can be tracked simultaneously in order to gain and improve statistics. Furthermore we show our results for different beads with hydrodynamic diameters between 200 and 1000 nm from diverse manufacturers. These measurement data can, for example, be used to determine design parameters for a magnetic separation system, like maximum flow rate and minimum separation time, or to select suitable beads for fixed experimental requirements.}, language = {en} } @article{RabehiGarlanAchtsnichtetal.2018, author = {Rabehi, Amine and Garlan, Benjamin and Achtsnicht, Stefan and Krause, Hans-Joachim and Offenh{\"a}usser, Andreas and Ngo, Kieu and Neveu, Sophie and Graff-Dubois, Stephanie and Kokabi, Hamid}, title = {Magnetic detection structure for Lab-on-Chip applications based on the frequency mixing technique}, series = {Sensors}, volume = {18}, journal = {Sensors}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s18061747}, pages = {14 Seiten}, year = {2018}, abstract = {A magnetic frequency mixing technique with a set of miniaturized planar coils was investigated for use with a completely integrated Lab-on-Chip (LoC) pathogen sensing system. The system allows the detection and quantification of superparamagnetic beads. Additionally, in terms of magnetic nanoparticle characterization ability, the system can be used for immunoassays using the beads as markers. Analytical calculations and simulations for both excitation and pick-up coils are presented; the goal was to investigate the miniaturization of simple and cost-effective planar spiral coils. Following these calculations, a Printed Circuit Board (PCB) prototype was designed, manufactured, and tested for limit of detection, linear response, and validation of theoretical concepts. Using the magnetic frequency mixing technique, a limit of detection of 15 µg/mL of 20 nm core-sized nanoparticles was achieved without any shielding.}, language = {en} } @article{SchlamannVoigtMaderwaldetal.2010, author = {Schlamann, Marc and Voigt, Melanie A. and Maderwald, Stefan and Bitz, Andreas and Kraff, Oliver and Ladd, Susanne C. and Ladd, Mark E. and Forsting, Michael and Wilhelm, Hans}, title = {Exposure to high-field MRI does not affect cognitive function}, series = {Journal of Magnetic Resonance Imaging}, volume = {31}, journal = {Journal of Magnetic Resonance Imaging}, number = {5}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2586}, doi = {10.1002/jmri.22065}, pages = {1061 -- 1066}, year = {2010}, abstract = {Purpose To assess potential cognitive deficits under the influence of static magnetic fields at various field strengths some studies already exist. These studies were not focused on attention as the most vulnerable cognitive function. Additionally, mostly no magnetic resonance imaging (MRI) sequences were performed. Materials and Methods In all, 25 right-handed men were enrolled in this study. All subjects underwent one MRI examination of 63 minutes at 1.5 T and one at 7 T within an interval of 10 to 30 days. The order of the examinations was randomized. Subjects were referred to six standardized neuropsychological tests strictly focused on attention immediately before and after each MRI examination. Differences in neuropsychological variables between the timepoints before and after each MRI examination were assessed and P-values were calculated Results Only six subtests revealed significant differences between pre- and post-MRI. In these tests the subjects achieved better results in post-MRI testing than in pre-MRI testing (P = 0.013-0.032). The other tests revealed no significant results. Conclusion The improvement in post-MRI testing is only explicable as a result of learning effects. MRI examinations, even in ultrahigh-field scanners, do not seem to have any persisting influence on the attention networks of human cognition immediately after exposure.}, language = {en} } @article{AchtsnichtNeuendorfFassbenderetal.2019, author = {Achtsnicht, Stefan and Neuendorf, Christian and Faßbender, Tobias and N{\"o}lke, Greta and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim and Schr{\"o}per, Florian}, title = {Sensitive and rapid detection of cholera toxin subunit B using magnetic frequency mixing detection}, series = {Plos One}, volume = {14}, journal = {Plos One}, number = {7}, publisher = {Plos}, address = {San Francisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0219356}, pages = {e0219356}, year = {2019}, abstract = {Cholera is a life-threatening disease caused by the cholera toxin (CT) as produced by some Vibrio cholerae serogroups. In this research we present a method which directly detects the toxin's B subunit (CTB) in drinking water. For this purpose we performed a magnetic sandwich immunoassay inside a 3D immunofiltration column. We used two different commercially available antibodies to capture CTB and for binding to superparamagnetic beads. ELISA experiments were performed to select the antibody combination. The beads act as labels for the magnetic frequency mixing detection technique. We show that the limit of detection depends on the type of magnetic beads. A nonlinear Hill curve was fitted to the calibration measurements by means of a custom-written python software. We achieved a sensitive and rapid detection of CTB within a broad concentration range from 0.2 ng/ml to more than 700 ng/ml.}, language = {en} }