TY  - JOUR
A1  - Schöning, Michael Josef
A1  - Poghossian, Arshak
A1  - Schultze, Joachim W.
T1  - Measuring seven parameters by two ISFET modules in a microcell set-up
JF  - Int. Journal of Computational Engineering Science. 4 (2003), H. 2
Y1  - 2003
SN  - 1465-8763
SP  - 257
EP  - 260
ER  - 
TY  - JOUR
A1  - Weigand, Christoph
T1  - Technically Optimal Inspection Policy with Arithmetical Adaption
JF  - IMA Journal of Management Mathematics. 14 (2003), H. 4
Y1  - 2003
SN  - 1471-678X
N1  - weitere ISSN 1471-6798 (E)
SP  - 357
EP  - 371
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  - BOOK
A1  - Staat, Manfred
A1  - Heitzer, Michael
T1  - Numerical methods for limit and shakedown analysis. Deterministic and probabilistic problems.
Y1  - 2003
SN  - 3-00-010001-6
N1  - NIC Series Vol. 15 / Ed. by Staat, M; Heitzer, M.
PB  - John von Neumann Institute for Computing (NIC)
CY  - Jülich
ER  - 
TY  - JOUR
A1  - Baroud, Gamal
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  - Heinrichs, U.
A1  - Pietrzyk, Uwe
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  -