Biomedical Technology (eBook)

Preface 6
Contents 8
Part I Biological Systems 11
Multiscale Aspects in the Multiphasic Modelling of Human Brain Tissue 12
1 Introduction and Motivation 12
2 Anatomic Elements of Human Brain Tissue 14
3 TPM Model of the Overall Brain-Tissue Aggregate 14
4 Microscopically Underlaid Macroscopic Constitutive Relation 16
4.1 Microscopic Model Settings 16
4.2 Macroscopic Constitutive Relation 19
4.3 Results and Discussion 20
References 22
Simulation of Steatosis Zonation in Liver Lobule---A Continuummechanical Bi-Scale, Tri-Phasic, Multi-Component Approach 23
1 Introduction 23
2 Glucose and Fat Metabolism 26
3 Numerical Example: Comparison of Different Assumptions for the Perfusion Coupled to the Metabolism 28
3.1 Discussion 30
References 40
3 Nano-Mechanical Tensile Behavior of the SPTA1 Gene in the Presence of Hereditary Hemolytic Anemia-Related Point Mutations 42
Abstract 42
1 Introduction 43
2 Spectrin Structure 44
3 Materials and Methods 45
4 Results 46
5 Discussion 53
Acknowledgements 53
References 53
The Choice of a Performance Indicator of Release in Transdermal Drug Delivery Systems 55
1 Introduction 55
2 The Concept of an Effective Time Constant: Definition and Applications 58
3 A One-Layer Model for TDD 60
4 Computation of the ETC for a One-Layer Skin Model 62
5 A Multi-layer Model for TDD 63
6 Computation of the ETC for a Multi-layer Skin Model 65
7 Computational Results 66
8 Conclusions 68
References 69
Part II Cardiovascular Medicine 71
5 Multiscale Multiphysic Approaches in Vascular Hemodynamics 72
Abstract 72
1 Introduction 72
2 Geometry Creation and General Simulation Settings 73
3 Boundary Conditions 74
3.1 Lumped Parameter Modeling 75
3.2 0-D/3-D Coupling 75
4 Fluid-Structure-Interaction 75
4.1 0-D/3-D Coupling of FSI Simulations 76
5 Examples 77
5.1 An FSI Model of Cardiopulmonary Bypass with Cerebral Autoregulation 77
5.2 A CFD Model of VAD Support Using Closed-Loop Multiscale Simulations to Evaluate Various Cannulation Strategies 77
5.3 A Numerical Framework to Investigate Hemodynamics During Endovascular Mechanical Recanalization in Acute Stroke 79
6 Conclusion 80
References 81
Heart Valve Flow Computation with the Space--Time Slip Interface Topology Change (ST-SI-TC) Method and Isogeometric Analysis (IGA) 82
1 Introduction 83
2 ST-VMS and ST-SI Formulations 86
2.1 ST-VMS Formulation 86
2.2 ST-SI Formulation 87
3 ST-SI-TC-IGA Method 89
3.1 ST-SI Method 89
3.2 ST-TC Method 90
3.3 ST-IGA Method 90
3.4 Integration of the ST-SI, ST-TC and ST-IGA Methods 90
4 Aortic-Valve Model 93
4.1 Geometry 93
4.2 Mesh and Flow Conditions 93
4.3 Computational Conditions 94
4.4 Results 96
5 Concluding Remarks 96
References 99
Estimation of Element-Based Zero-Stress State in Arterial FSI Computations with Isogeometric Wall Discretization 105
1 Introduction 106
2 Element-Based Total Lagrangian (EBTL) Method 107
2.1 EBZSS 107
2.2 NURBS Basis Functions 108
2.3 EBZSS Representation with NURBS Basis Functions 110
3 Modeling the Artery ZSS: Straight-Tube ZSS Template 112
4 2D Test Computations 113
4.1 Meshes 113
4.2 Curvature Matching in the ZSS 116
4.3 Computational Results 118
5 Concluding Remarks 122
References 123
Fluid-Structure Interaction Modeling in 3D Cerebral Arteries and Aneurysms 127
1 Introduction 127
2 Fluid-Structure Interaction: Mathematical Formulation 129
2.1 Partitioned Algorithm 132
3 Fictitious Methods 133
3.1 Analysis of an Idealized Artery Model 134
4 Fractional-Order Viscoelastic Model for Aneurysm Walls 136
5 Numerical Simulations 140
5.1 Blood Flow in an Artery 140
5.2 Blood Flow in a Patient-Specific Aneurysm 144
6 Conclusion and Future Work 147
References 148
Large-Eddy Simulation of Turbulence in Cardiovascular Flows 151
1 Introduction 151
2 LES Requirements 153
3 The FDA Medical Device Test Case 155
3.1 Simulations with Perturbation-Free Inlet 156
3.2 Small Perturbations at the Inlet 157
4 Intracardiac Turbulence 159
4.1 Method 159
4.2 Results 160
4.3 Role of SGS Model 161
4.4 Discussion 163
5 Cardiac Valves 163
6 Conclusion 168
References 169
Computational Comparison Between Newtonian and Non-Newtonian Blood Rheologies in Stenotic Vessels 172
1 Introduction 172
2 Materials and Methods 174
2.1 Computational Domains and Mesh Generation 174
2.2 Mathematical and Numerical Methods 175
3 Results 177
3.1 Carotid Arteries 177
3.2 Coronary Arteries 181
4 Conclusions 183
References 184
Artificial Textile Reinforced Tubular Aortic Heart Valves---Multi-scale Modelling and Experimental Validation 187
1 Introduction 188
1.1 Motivation 188
1.2 Previous Work 188
1.3 Present Work 191
2 Bio-Engineered Aortic Heart Valves with a Tubular Leaflet Design 192
3 Experiments 193
4 Finite Element Simulations 194
4.1 Multi-scale Modelling 194
4.2 Fibre Level Structural Model 196
4.3 Knit Level Structural Model 197
4.4 Textile Level Structural Model 198
4.5 Virtual Textile Composite 200
4.6 Macro Level Heart Valve Model 201
5 Material Models 202
5.1 Transversely Isotropic Material Model 202
5.2 Arruda Boyce Material Model 202
5.3 Fung's Orthotropic Material Model 203
6 Results and Discussions 204
6.1 Characterization to Experimental Results 204
6.2 Numerical Results 205
6.3 Experimental Validation and Comparison 210
6.4 Heart Valve Model 211
7 Conclusion and Outlook 214
References 215
Preliminary Monolithic Fluid Structure Interaction Model for Ventricle Contraction 218
1 Introduction 218
2 Mathematical Model 219
2.1 The Coupled Fluid-Structure Problem 221
3 Numerical Penalty-Projection Algorithm 225
4 Numerical Results 227
4.1 Ventricle Model 227
4.2 FSI Ventricle Simulations 229
5 Conclusion 231
References 232
The Biomechanical Rupture Risk Assessment of Abdominal Aortic Aneurysms---Method and Clinical Relevance 233
1 Introduction 233
2 The Basic Concept of the Biomechanical Rupture Risk Assessment (BRRA) 234
2.1 Work Flow and Diagnostic Information 234
2.2 Complexity Versus Uncertainty of Model Predictions 236
3 AAA Tissue Characterization 237
3.1 Properties of the Normal Aorta 237
3.2 Aneurysm-Related Alteration of the Aorta 239
3.3 Modeling Frameworks 240
4 Clinical Validation 243
4.1 Quasi-static BRRA Computations 243
4.2 AAA Growth Prediction 245
5 Conclusions 246
References 247
Part III Dentistry 254
A Deeper Insight of a Multi-dimensional Continuum Biofilm Growth Model: Experimental Observation and Parameter Studies 255
1 Introduction 256
2 Mathematical Model 257
2.1 Governing Equations 257
2.2 Transformation Processes 258
3 Numerical Strategy 259
4 Biofilm Height After 24h: Experimental Observation and Numerical Simulation 259
4.1 Experiment Setup 259
4.2 Numerical Simulation and Results 260
5 Parameter Study of the Mathematical Model 261
5.1 Influence of Maximum Growth Rate ? 262
5.2 Influence of Monod Half-Rate Constant ks 264
5.3 Influence of Inactivation Rate ?i 265
5.4 Influence of Biofilm Yield Y 265
6 Summary and Conclusion 268
References 269
Multiscale Experimental and Computational Investigation of Nature's Design Principle of Hierarchies in Dental Enamel 271
1 Introduction 272
2 Microstructural Characteristics of Bovine Enamel 273
3 Multiscale Experimental Study of Mechanical Behavior of Dental Enamel 274
4 Multiscale Computational Simulation of Damage Behavior of Dental Enamel 276
4.1 Continuum Damage Model for Mineral Fiber and Protein 276
4.2 Protein--Mineral Interface 279
4.3 3D Computational Model of the Microstructure 280
4.4 Simulation Results of First and Second Hierarchy Levels 282
4.5 Influence of Initial Flaw at Different Hierarchical Levels 284
5 Conclusions 287
References 288
Part IV Orthopaedics 290
16 Challenges in Total Hip Arthroplasty 291
Abstract 291
1 Challenges of Total Hip Arthroplasty (THA) 291
1.1 Changes in Indication for Implantation of a Total Hip Arthroplasty 291
2 Influence of Demographic Changes on Osteoarthritis of the Hip 292
3 Joint Replacement Registers 293
4 Challenges of THA During Different Lifetime Periods 293
5 Challenges of Revision THA 297
6 Patients and Methods 298
7 Results 302
8 Discussion 303
9 Conclusion 305
References 306
Personalized Orthopedic Trauma Surgery by Applied Clinical Mechanics 309
1 Introduction 309
2 Methods 311
2.1 Preparation and Tomography of the Fracture Model 311
2.2 Image Processing 311
2.3 Mesh Generation 312
2.4 Material Assignment 315
2.5 Set-up of the Numerical Simulations 315
2.6 Optimization Strategy 316
3 Results and Discussion 317
3.1 Numerical Simulation with Perfect Bone Formation in the Pseudarthrosis Area---Best-Case Scenario 319
3.2 Numerical Simulation with Totally Absent Bone Formation in the Pseudarthrosis Area---Worst-Case Scenario 321
3.3 Impact of the Optimization Parameter on the Results 325
4 Conclusion and Outlook 325
5 Conflict of Interest 326
References 326
Part V Otology 328
18 Measurement of Intracochlear Pressure Differences in Human Temporal Bones Using an Off-the-Shelf Pressure Sensor 329
Abstract 329
1 Introduction 330
2 Materials and Methods 331
2.1 TB Preparation 331
2.2 Experimental Setup 331
2.3 Intracochlear Pressure Measurement 331
2.4 Vibration Measurement 332
2.5 Experimental Procedure 332
2.6 Signal Generation, Acquisition and Analysis 333
3 Results 334
3.1 SFP Vibration Responses Before and After Cochleostomy 334
3.2 Sound Pressures in Scala Vestibuli and Scala Tympani 334
3.3 Intracochlear Pressure Differences 336
4 Discussion 337
4.1 Effect of Transducer Insertion on SFP Vibration Responses 337
4.2 Comparison to Previous Work with Custom-Made Pressure Sensors 338
5 Conclusion 340
References 340
Development of a Parametric Model of the Electrically Stimulated Auditory Nerve 343
1 Introduction 344
2 Methods 344
2.1 3D Cochlear Geometry and Finite Element Model 344
2.2 Auditory Nerve Model 345
2.3 Evoked Compound Action Potentials (ECAPs) 349
2.4 Parameterization of the Auditory Nerve Model 350
3 Results 352
3.1 Simulation of the ECAP Using the Forward Masking Technique 352
3.2 Effects of Different Amounts of Nerve Degeneration and Nerve Density on AGF 353
4 Discussion 353
References 354