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بررسی رفتار تحریک - انقباض در بافت عضله اسکلتی به کمک مدل‌سازی شیمی - مکانیک
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بررسی رفتار تحریک - انقباض در بافت عضله اسکلتی به کمک مدل‌سازی شیمی - مکانیک

کرمی، مینا Karami, Mina

Investigation of Excitation-contraction behavior in Skeletal Muscle by Means of Chemomechanical Modeling

Karami, Mina | 2020

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 53857 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Zohoor, Hassan; Firoozbakhsh, Keikhosrow
  7. Abstract:
  8. Numerous studies have shown a direct relationship between skeletal muscle active force and intracellular calcium ion concentrations; In fact, no matter how the muscle is stimulated (neurological, electrical, chemical, and mechanical stimuli), the main cause of muscle activation and consequently force generation is calcium ions.According to this scientific finding, the purpose of this study is to present a new chemo-mechanical multiscale model of skeletal muscle based on the fundamental principles of continuum thermodynamics. In this model, unlike other similar studies, muscle active force is not considered as the conventional multiplication of isometric force in a set of corrective experimental functions. This model, which satisfies thermodynamic compatibility in all conditions, can be used in three-dimensional analysis. With the help of this model, it is possible to study the phenomena affected by chemical changes in muscles, such as fatigue.In a case study, the proposed model was used to predict fatigue behavior in rabbit EDL muscle. The results show that this model is able to accurately predict the maximum amount of force produced by muscle in fatigue conditions by changing the level of intracellular calcium ions and also muscle sensitivity to this ion. The simulated results of the muscle contraction cycle under fatigue conditions with a mean NRMSE = 16% are consistent with laboratory data. Fatigue behavior can be more accurately predicted by considering the kinematics of other chemical ions in addition to calcium ones as well as the dependence of actin and myosin separation rate on intracellular calcium ion concentrations.In the next study, the material model was used to investigate the human abdominal wall with a real geometry. In this 3D model, the initial strain of the muscles was estimated numerically. Then, the effect of calcium ion activation for different muscles was adjusted according to the EMG data reported in a similar experimental study and the amount of intra-abdominal pressure (IAP) was calculated by the model. Simulated model estimated an IAP equal to 42 mmHg; as in the experimental study [1] the IAP was reported in the range of 37-55 mmHg with mean value of 46 mmHg. Valid estimation of the result demonstrates that the material model was able to establish a good relationship between calcium ion levels and muscle activities. Hence, such a model can be used as a virtual laboratory of the human abdominal wall for further research in this field
  9. Keywords:
  10. Fatigue ; Calcium Ion ; Three Dimensional Modeling ; Abdominal Muscles ; Intra Abdominal Pressure (IAP) ; Active Behavior ; Passive Behavior ; Material Model ; Skeletal Muscle ; Chemomechanical Modeling

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