TY  - CHAP
A1  - Bhattarai, Aroj
A1  - Frotscher, Ralf
A1  - Staat, Manfred
T1  - Computational Analysis of Pelvic Floor Dysfunction
T2  - Women's Health and Biomechanics
N2  - Pelvic floor dysfunction (PFD) is characterized by the failure of the levator ani (LA) muscle to maintain the pelvic hiatus, resulting in the descent of the pelvic organs below the pubococcygeal line. This chapter adopts the modified Humphrey material model to consider the effect of the muscle fiber on passive stretching of the LA muscle. The deformation of the LA muscle subjected to intra-abdominal pressure during Valsalva maneuver is compared with the magnetic resonance imaging (MRI) examination of a nulliparous female. Numerical result shows that the fiber-based Humphrey model simulates the muscle behavior better than isotropic constitutive models. Greater posterior movement of the LA muscle widens the levator hiatus due to lack of support from the anococcygeal ligament and the perineal structure as a consequence of birth-related injury and aging. Old and multiparous females with uncontrolled urogenital and rectal hiatus tend to develop PFDs such as prolapse and incontinence.
KW  - Pelvic muscle
KW  - Muscle fibers
KW  - Passive stretching
KW  - Pelvic floor dysfunction
Y1  - 2018
SN  - 978-3-319-71574-2
U6  - http://dx.doi.org/10.1007/978-3-319-71574-2_17
N1  - Lecture Notes in Computational Vision and Biomechanics, vol 29
SP  - 217
EP  - 230
PB  - Springer
CY  - Cham
ER  - 
TY  - CHAP
A1  - Frotscher, Ralf
A1  - Goßmann, Matthias
A1  - Raatschen, Hans-Jürgen
A1  - Temiz Artmann, Aysegül
A1  - Staat, Manfred
T1  - Simulation of cardiac cell-seeded membranes using the edge-based smoothed FEM
T2  - Shell and membrane theories in mechanics and biology. (Advanced structured materials ; 45)
N2  - We present an electromechanically coupled Finite Element model for cardiac tissue. It bases on the mechanical model for cardiac tissue of Hunter et al. that we couple to the McAllister-Noble-Tsien electrophysiological model of purkinje fibre cells. The corresponding system of ordinary differential equations is implemented on the level of the constitutive equations in a geometrically and physically nonlinear version of the so-called edge-based smoothed FEM for plates. Mechanical material parameters are determined from our own pressure-deflection experimental setup. The main purpose of the model is to further examine the experimental results not only on mechanical but also on electrophysiological level down to ion channel gates. Moreover, we present first drug treatment simulations and validate the model with respect to the experiments.
Y1  - 2015
SN  - 978-3-319-02534-6 ; 978-3-319-02535-3
SP  - 187
EP  - 212
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - CHAP
A1  - Frotscher, Ralf
A1  - Staat, Manfred
ED  - Artmann, Gerhard
ED  - Temiz Artmann, Aysegül
ED  - Zhubanova, Azhar A.
ED  - Digel, Ilya
T1  - Towards Patient-Specific Computational Modeling of hiPS-Derived Cardiomyocyte Function and Drug Action
T2  - Biological, Physical and Technical Basics of Cell Engineering
N2  - Human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CM) today are widely used for the investigation of normal electromechanical cardiac function, of cardiac medication and of mutations. Computational models are thus established that simulate the behavior of this kind of cells. This section first motivates the modeling of hiPS-CM and then presents and discusses several modeling approaches of microscopic and macroscopic constituents of human-induced pluripotent stem cell-derived and mature human cardiac tissue. The focus is led on the mapping of the computational results one can achieve with these models onto mature human cardiomyocyte models, the latter being the real matter of interest. Model adaptivity is the key feature that is discussed because it opens the way for modeling various biological effects like biological variability, medication, mutation and phenotypical expression. We compare the computational with experimental results with respect to normal cardiac function and with respect to inotropic and chronotropic drug effects. The section closes with a discussion on the status quo of the specificity of computational models and on what challenges have to be solved to reach patient-specificity.
Y1  - 2018
SN  - 978-981-10-7904-7
U6  - http://dx.doi.org/10.1007/978-981-10-7904-7_10
SP  - 233
EP  - 250
PB  - Springer
CY  - Singapore
ER  -