TY  - JOUR
A1  - Baroud, G.
A1  - Wu, J.Z.
A1  - Bohner, M
A1  - Sponagel, Stefan
A1  - Steffen, T.
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  - Bressel, A.
A1  - Schultze, J.W.
A1  - Khan, W.
A1  - Wolfaardt, G. M.
A1  - Rohns, H.-P.
A1  - Irmscher, R.
A1  - Schöning, Michael Josef
T1  - High resolution gravimetric, optical and electrochemical investigations of microbial biofilm formation in aqueous systems
JF  - Electrochimica Acta. 48 (2003), H. 20-22
Y1  - 2003
SN  - 0013-4686
SP  - 3363
EP  - 3372
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Leipold, M.
A1  - Fichtner, H.
T1  - Heliopause Explorer - A Sailcraft Mission to the Outer Boundaries of the Solar System / M. Leipold ; H. Fichtner ; B. Heber  ... B. Dachwald ...
JF  - Proceedings of the Fifth IAA International Conference on Low Cost Planetary Missions : 24 - 26 September 2003, ESTEC, Noordwijk, the Netherlands / [comp. by R. A. Harris]
Y1  - 2003
SN  - 92-9092-853-0
N1  - International Conference on Low Cost Planetary Missions <5, 2003, Noordwijk> ; International Academy of Astronautics ; European Space Research and Technology Centre
SP  - 367
EP  - 375
PB  - ESA
CY  - Noordwijk
ER  - 
TY  - JOUR
A1  - Heuermann, Holger
T1  - GSOLT: the calibration procedure for all multi-port vector network analyzers
JF  - IEEE MTT-S International Microwave Symposium digest : Philadelphia, Pennsylvania, 8 - 13 June 2003 ; [including: 2003 International Microwave Symposium digest, vol. 1-3, RF Integrated Circuit Symposium digest, Automatic RF Techniques Group Symposium digest . Vol. 3
Y1  - 2003
SN  - 0-780-37696-X
N1  - Nebent.: 2003 IEEE MTT-S International Microwave Symposium
SP  - 1815
EP  - 1818
PB  - IEEE
CY  - Piscataway, NJ
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Yoshinobu, Tatsuo
A1  - Schöning, Michael Josef
T1  - Flow-velocity microsensors based on semiconductor field-effect structures
JF  - Sensors. 3 (2003), H. 7
Y1  - 2003
SN  - 1424-8220
SP  - 202
EP  - 212
ER  - 
TY  - JOUR
A1  - Wang, J.
A1  - Krause, R.
A1  - Block, K.
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  - Dachwald, Bernd
A1  - Schmidt, Tanja D.
A1  - Seboldt, Wolfgang
A1  - Auweter-Kurtz, 
T1  - Flight Opportunities from Mars to Earth for Piloted Missions Using Continuous Thrust Propulsion / Schmidt, Tanja D. ; Dachwald, Bernd ; Seboldt, Wolfgang ; Auweter-Kurtz, Monika
Y1  - 2003
N1  - 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit
20-23 July 2003, Huntsville, Alabama ; AIAA 2003-4573
SP  - 1
EP  - 9
PB  - -
ER  - 
TY  - JOUR
A1  - Oßmann, Martin
A1  - Hattrup, C.
A1  - Broeck, H. W. van der
T1  - Fast estimation techniques for digital control of resonant converters / Hattrup, C.; van der Broeck, H.W.; Ossmann, M.;
JF  - IEEE Transaction on Power Electronics. 18 (2003), H. 1
Y1  - 2003
SN  - 0885-8993
N1  - Part 2
SP  - 365
EP  - 372
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Fritz, Christian
A1  - Lakemeyer, Gerhard
T1  - Extending DTGOLOG with Options / Ferrein, Alexander ; Fritz, Christian ; Lakemeyer, Gerhard
JF  - IJCAI-03, Proceedings of the Eighteenth International Joint Conference on Artificial Intelligence, Acapulco, Mexico, August 9-15, 2003
Y1  - 2003
SP  - 1391
EP  - 1393
ER  - 
TY  - JOUR
A1  - Bohn, Dieter
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  - Kämper, Klaus-Peter
T1  - Education and Training in MST. Kämper, K.-P.; Picard, A.; Brill, M.; Cassel, D.; Jentsch, A.; Merten, S.; Rollwa, M.
JF  - Mst-News (2003)
Y1  - 2003
SN  - 0948-3128
SP  - 35
ER  - 
TY  - JOUR
A1  - Weigand, Christoph
T1  - Economically Optimal Inspection Policy with Geometrical Adaption
JF  - Journal of Applied Statistics. 30 (2003), H. 5
Y1  - 2003
SN  - 0266-4763
N1  - weitere ISSN 1360-0532 (E)
SP  - 555
EP  - 569
ER  - 
TY  - JOUR
A1  - Keusgen, M.
A1  - Jünger, M.
A1  - Krest, I.
A1  - Schöning, Michael Josef
T1  - Development of a biosensor specific for cysteine sulfoxides
JF  - Biosensors & Bioelectronics. 18 (2003), H. 5-6
Y1  - 2003
SN  - 0956-5663
SP  - 805
EP  - 812
ER  - 
TY  - JOUR
A1  - Grap, Rolf Dietmar
T1  - Determining manpower requirements in a spinning mill
JF  - Chemical fibers international : CFI ; fiber polymers, fibers, texturing, and spunbonds (2003)
Y1  - 2003
SN  - 0340-3343
SP  - 455
EP  - 458
ER  - 
TY  - JOUR
A1  - Heinrichs, U.
A1  - Pietrzyk, U.
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  - Heinrichs, U.
A1  - Pietrzyk, U.
A1  - Ziemons, Karl
T1  - Design optimization of the PMT-ClearPET prototypes based on simulation studies with GEANT3
JF  - IEEE Transactions on Nuclear Science
N2  - Within the Crystal Clear Collaboration (CCC), four centers are developing second generation high performance small animal positron emission tomography (PET) scanners for different kinds of animals and medical applications. The first prototypes are photomultiplier tube (PMT)-based systems including depth of interaction (DOI) detection by using a phoswich layer of lutetium oxyorthosilicate (LSO) and lutetium yttrium aluminum perovskite (LuYAP). The aim of these simulation studies is to optimize sensitivity and spatial resolution of given designs, which vary in fields of view (FOVs) caused by different detector configurations (ring/octagon) and sizes. For this purpose the simulation tool GEANT3 (CERN, Geneva, Switzerland) was used.
Y1  - 2003
SN  - 0018-9499
VL  - 50
IS  - 5
SP  - 1428
EP  - 1432
ER  - 
TY  - JOUR
A1  - Staat, Manfred
A1  - Schwartz, M.
A1  - Lang, H.
A1  - Wirtz, K.
A1  - Heitzer, M.
T1  - Design by Analysis of Pressure Components by non-linear Optimization
JF  - The 10th International Conference on Pressure Vessel Technology, July 7-10, 2003, Vienna, Austria, Proceedings ICPVT-10 / Zeman, J. L. [ed]
Y1  - 2003
SN  - 3950152814
SP  - 59
EP  - 65
PB  - ÖGS, Österreichische Gesellschaft für Schweißtechnik
CY  - Wien
ER  - 
TY  - JOUR
A1  - Hoffschmidt, Bernhard
A1  - Fend, Thomas
A1  - Jorgensen, Gary
A1  - Küster, Harald
T1  - Comparative assessment of solar concentrator materials / Fend, Thomas ; Hoffschmidt, Bernhard ; Jorgensen, Gary ; Küster, Harald ; Krüger, Dirk ; Pitz-Paal, Robert ; Riebrock, Peter ; Riffelmann, Klaus-Jürgen
JF  - Solar energy. 74 (2003), H. 2
Y1  - 2003
SN  - 0038-092X
SP  - 149
EP  - 155
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Berndsen, Lars
A1  - Schöning, Michael Josef
T1  - Chemical sensor as physical sensor: ISFET-based flowvelocity, flow-direction and diffusion-coefficient sensor
JF  - Sensors and Actuators B. 95 (2003), H. 1-3
Y1  - 2003
SN  - 0925-4005
SP  - 384
EP  - 390
ER  - 
TY  - JOUR
A1  - Palmer, J. W.
A1  - Lindemann, Markus
T1  - Business models and market mechanisms : evaluating efficiency in consumer electronic markets
JF  - Data base and advanced information systems. Bd. 34 (2003), H. 2
Y1  - 2003
SN  - 0105-9912
SP  - 23
EP  - 38
ER  -