TY - JOUR A1 - Heinrichs, U. A1 - Pietrzyk, Uwe A1 - Ziemons, Karl T1 - Design optimization of the PMT-ClearPET prototypes based on simulation studies with GEANT3 JF - 2002 IEEE Nuclear Science Symposium Conference Record, Vol. 3 N2 - Within the Crystal Clear Collaboration four centres are developing 2nd generation high performance small animal PET scanners for different kinds of animals and medical applications. The first prototypes are PMT-based systems including depth of interaction (DOI) detection by using a phoswich layer of LSO and LuYAP. The aim of these simulation studies is to optimize sensitivity and spatial resolution of given designs, which vary in FOVs caused by different detector configurations (ring/octagon) and sizes. For this purpose the simulation tool GEANT3 (CERN) was used. The simulations have shown that all PMT designs with one-to-one coupling of crystals have a very nonlinear axial sensitivity profile. By shifting every other PMT 1/4 of a PMT length in axial direction the sampling of the FOVs became more homogeneous. At an energy threshold of 350keV the regression coefficient increases from 0.818 for the non-shifted to 0.993 for the shifted design. Simulations of a point source centred in the FOV (threshold: 350keV) resulted in sensitivities of 4.2% for a 4×20PMT (LSO/LuYAP a 10mm) and 3.8% for a 4×16PMT (LSO/LuYAP a 8mm) ring design. The 3D-MLEM reconstruction of a point source shows the enormous improvement of resolution using a crystal double layer with DOI (3.1mm at 40mm from CFOV) instead of a 20mm single layer (11.9mm). Y1 - 2003 SN - 1082-3654 SP - 682 EP - 686 ER - TY - JOUR A1 - Schöning, Michael Josef A1 - Krause, Robin A1 - Block, Kirstin A1 - Musahmeh, Mustafa A1 - Mulchandani, Ashok A1 - Wang, Joseph T1 - A dual amperometric/potentiometric FIA-based biosensor for the distinctive detection of organophosphorus pesticides JF - Sensors and Actuators B. 95 (2003), H. 1-3 Y1 - 2003 SN - 0925-4005 SP - 291 EP - 296 ER - TY - JOUR A1 - Wang, J. A1 - Krause, R. A1 - Block, Kirstin A1 - Musameh, M. A1 - Mulchandani, A. A1 - Schöning, Michael Josef T1 - Flow injection amperometric detection of OP nerve agents based on organophosphorus-hydrolase biosensor detector JF - Biosensors & Bioelectronics. 18 (2003), H. 2-3 Y1 - 2003 SN - 0956-5663 SP - 255 EP - 260 ER - TY - JOUR A1 - Baroud, Gamal A1 - Wu, J.Z. A1 - Bohner, Marc A1 - Sponagel, Stefan A1 - Steffen, Thomas T1 - How to determine the permeability for cement infiltration into osteoporotic cancellous bone JF - Medical Engineering & Physics. 25 (2003), H. 4 N2 - Cement augmentation is an emerging surgical procedure in which bone cement is used to infiltrate and reinforce osteoporotic vertebrae. Although this infiltration procedure has been widely applied, it is performed empirically and little is known about the flow characteristics of cement during the injection process. We present a theoretical and experimental approach to investigate the intertrabecular bone permeability during the infiltration procedure. The cement permeability was considered to be dependent on time, bone porosity, and cement viscosity in our analysis. In order to determine the time-dependent permeability, ten cancellous bone cores were harvested from osteoporotic vertebrae, infiltrated with acrylic cement at a constant flow rate, and the pressure drop across the cores during the infiltration was measured. The viscosity dependence of the permeability was determined based on published experimental data. The theoretical model for the permeability as a function of bone porosity and time was then fit to the testing data. Our findings suggest that the intertrabecular bone permeability depends strongly on time. For instance, the initial permeability (60.89 mm4/N.s) reduced to approximately 63% of its original value within 18 seconds. This study is the first to analyze cement flow through osteoporotic bone. The theoretical and experimental models provided in this paper are generic. Thus, they can be used to systematically study and optimize the infiltration process for clinical practice. KW - Osteoporose KW - Permeabilität KW - Viskose Strömung KW - Viskosität KW - Vertebroplastie KW - Cement infiltration KW - Vertebroplasty KW - Osteoporosis KW - Permeability KW - Experiment KW - Analysis KW - Viscous flow Y1 - 2003 SN - 1350-4533 SP - 283 EP - 288 ER - TY - JOUR A1 - Bohn, Dieter E. A1 - Funke, Harald T1 - Experimental investigations into the nonuniform flow in a 4-stage turbine with special focus on the flow equalization in the first turbine stage JF - ASME TURBO EXPO, Proceedings of the ASME Turbo Expo, 2003 Y1 - 2003 SN - 0-7918-3689-4 N1 - ASME TURBO EXPO 2003, Proceedings, Vol. 6: Turbomachinery, Pt. A, Atlanta, US, Jun 16-19, 2003 SP - 281 EP - 289 ER - TY - JOUR A1 - Enning, Manfred A1 - Bollig, Alexander A1 - Mann, S. A1 - Kaierle, Stefan T1 - Autonome Produktionszelle für das Laserstrahlschweißen / Bollig, A. ; Mann, S. ; Enning, M. ; Kaierle, S. ; Abel, D. ; Poprawe, R. JF - Automation und Information in Wirtschaft und Gesellschaft : Kongress Baden-Baden, 3. und 4. Juni 2003 / VDI-VDE-Gesellschaft Mess- und Automatisierungstechnik Y1 - 2003 SN - 3-18-091756-3 N1 - GMA-Kongress ; 2003 ; VDI-Berichte 1756 SP - 73 EP - 82 PB - VDI-Verl. CY - Düsseldorf ER - TY - JOUR A1 - Enning, Manfred A1 - Mann, S. A1 - Bollig, Alexander A1 - Kaierle, Stefan T1 - Autonomous Production Cell for Laser Beam Welding / Mann S. ; Bollig, A. ; Kaierle, S. ; Abel, D. ; Poprawe, R. Y1 - 2003 SN - 0912035757 N1 - ICALEO 2003, Florida ; Laser Materials Processing Conference ; (2003, Jacksonville, Fla.) ; ICALEO ; (22, 2003, Jacksonville, Fla.) PB - LIA CY - Orlando, Fla ER - TY - BOOK A1 - Grundmann, Reinhard A1 - Bommes, Leonhard A1 - Fricke, Jürgen T1 - Ventilatoren Y1 - 2003 SN - 3-8027-3200-6 N1 - Mitherausgeber und Mitautor PB - Vulkan-Verlag CY - Essen ER - TY - CHAP A1 - Wollert, Jörg F. T1 - Einsatz von Wireless Technologien im Kraftfahrzeug T2 - Sichere Datenkommunikation im Automobil : Kongress ; 18. - 19. November 2003, Radisson SAS Hotel, Köln Y1 - 2003 SP - Getr. Zählung CY - Köln ER - TY - JOUR A1 - Wollert, Jörg F. T1 - Dot net und Sun ONE - Wettbewerb oder Mitspieler? Neue Programmiermodelle machen das Web interaktiv JF - Elektronik : Fachmedium für industrielle Anwender und Entwickler Y1 - 2003 SN - 0013-5658 N1 - Printausg. in der Bibliothek vorhanden: 63 ZS 030; 23 Z 263 VL - Bd. 52 IS - H. 19 SP - 72 EP - 81 ER -