TY - JOUR A1 - Riedl, Katharina A. A1 - Kampf, Thomas A1 - Herold, Volker A1 - Behr, Volker C. A1 - Bauer, Wolfgang R. T1 - Wall shear stress analysis using 17.6 Tesla MRI: A longitudinal study in ApoE\(^{-/-}\)mice with histological analysis JF - PLoS One N2 - This longitudinal study was performed to evaluate the feasibility of detecting the interaction between wall shear stress (WSS) and plaque development. 20 ApoE\(^{-/-}\)mice were separated in 12 mice with Western Diet and 8 mice with Chow Diet. Magnetic resonance (MR) scans at 17.6 Tesla and histological analysis were performed after one week, eight and twelve weeks. Allin vivoMR measurements were acquired using a flow sensitive phase contrast method for determining vectorial flow. Histological sections were stained with Hematoxylin and Eosin, Elastica van Gieson and CD68 staining. Data analysis was performed using Ensight and a Matlab-based "Flow Tool". The body weight of ApoE\(^{-/-}\)mice increased significantly over 12 weeks. WSS values increased in the Western Diet group over the time period; in contrast, in the Chow Diet group the values decreased from the first to the second measurement point. Western Diet mice showed small plaque formations with elastin fragmentations after 8 weeks and big plaque formations after 12 weeks; Chow Diet mice showed a few elastin fragmentations after 8 weeks and small plaque formations after 12 weeks. Favored by high-fat diet, plaque formation results in higher values of WSS. With wall shear stress being a known predictor for atherosclerotic plaque development, ultra highfield MRI can serve as a tool for studying the causes and beginnings of atherosclerosis. KW - phase-contrast MRI KW - flow patterns KW - blood flow KW - apolipoprotein-E KW - atheriosclerosis KW - mouse KW - mice KW - quantification KW - association KW - lesions Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229318 VL - 15 IS - 8 ER - TY - JOUR A1 - Vogel, Patrick A1 - Markert, Jonathan A1 - Rückert, Martin A. A1 - Herz, Stefan A1 - Keßler, Benedikt A1 - Dremel, Kilian A1 - Althoff, Daniel A1 - Weber, Matthias A1 - Buzug, Thorsten M. A1 - Bley, Thorsten A. A1 - Kullmann, Walter H. A1 - Hanke, Randolf A1 - Zabler, Simon A1 - Behr, Volker C. T1 - Magnetic Particle Imaging meets computed tomography: first simultaneous imaging JF - Scientific Reports N2 - Magnetic Particle Imaging (MPI) is a promising new tomographic modality for fast as well as three-dimensional visualization of magnetic material. For anatomical or structural information an additional imaging modality such as computed tomography (CT) is required. In this paper, the first hybrid MPI-CT scanner for multimodal imaging providing simultaneous data acquisition is presented. KW - Applied physics KW - Biomedical engineering KW - Imaging techniques Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-202501 VL - 9 ER - TY - JOUR A1 - Franich, Robert A. A1 - Meder, Roger A1 - Behr, Volker C. T1 - Dewatering Green Sapwood Using Carbon Dioxide Undergoing Cyclical Phase Change between Supercritical Fluid and Gas JF - Molecules N2 - Conventional kiln drying of wood operates by the evaporation of water at elevated temperature. In the initial stage of drying, mobile water in the wood cell lumen evaporates. More slowly, water bound in the wood cell walls evaporates, requiring the breaking of hydrogen bonds between water molecules and cellulose and hemicellulose polymers in the cell wall. An alternative for wood kiln drying is a patented process for green wood dewatering through the molecular interaction of supercritical carbon dioxide with water of wood cell sap. When the system pressure is reduced to below the critical point, phase change from supercritical fluid to gas occurs with a consequent large change in CO2 volume. This results in the efficient, rapid, mechanical expulsion of liquid sap from wood. The end-point of this cyclical phase-change process is wood dewatered to the cell wall fibre saturation point. This paper describes dewatering over a range of green wood specimen sizes, from laboratory physical chemistry studies to pilot-plant trials. Magnetic resonance imaging and nuclear magnetic resonance spectroscopy were applied to study the fundamental mechanisms of the process, which were contrasted with similar studies of conventional thermal wood drying. In conclusion, opportunities and impediments towards the commercialisation of the green wood dewatering process are discussed. KW - supercritical CO2 KW - phase-change KW - sapwood KW - dewatering KW - physical chemistry KW - nuclear magnetic resonance spectroscopy KW - magnetic resonance imaging Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-219327 SN - 1420-3049 VL - 25 IS - 22 ER - TY - JOUR A1 - Horvat, Sonja A1 - Vogel, Patrick A1 - Kampf, Thomas A1 - Brandl, Andreas A1 - Alshamsan, Aws A1 - Alhadlaq, Hisham A. A1 - Ahamed, Maqusood A1 - Albrecht, Krystyna A1 - Behr, Volker C. A1 - Beilhack, Andreas A1 - Groll, Jürgen T1 - Crosslinked Coating Improves the Signal‐to‐Noise Ratio of Iron Oxide Nanoparticles in Magnetic Particle Imaging (MPI) JF - ChemNanoMat N2 - Magnetic particle imaging is an emerging tomographic method used for evaluation of the spatial distribution of iron‐oxide nanoparticles. In this work, the effect of the polymer coating on the response of particles was studied. Particles with covalently crosslinked coating showed improved signal and image resolution. KW - crosslinked coating KW - imaging agents KW - magnetic properties KW - MPI KW - MPS Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-214718 VL - 6 IS - 5 SP - 755 EP - 758 ER -