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The biomechanics problems of thinwalled brain veins
Hemza, Jan ; Maršík, František (advisor) ; Otáhal, Jakub (referee) ; Vašků, Anna (referee)
Biomechanical material properties of the bridging brain veins are investigated experimentally (A Nikon light microscope was used for the histo-anatomical study and viskoelastic properties was measured on a MTS 858.2 Mini Bionix system ) and theoretically. The main goal of the developed theory was to formulate the biomechanical conditions (geometrical dimensions, viscoelastic properties of veins and blood fluid flow conditions) at which unstable behavior or even vein collapse can occur. The study of the geometry and topology of bridging veins was carried out by a magnetic resonance (Siemens Magnetom Symphony1,5 T) and a stereomicroscope (Nikon SMZ 1500) complemented with a digital camera (Nikon Coolpix E995) and Lucia Net software. From the biomechanical point of view, experimental findings can be summarized as follows: the existence of two types of venous brain systems; thin and thick wall veins with a one order difference in elastic modulus magnitude high sensitivity of the thin wall veins on the blood flow rate and extension or contraction on their structural stability the existence of continuing small wall vibration under physiological conditions Under small deformations conditions, the shear modulus was shown experimentally to be in the range (2÷4)·10 4 Pa with a Young modulus E= (0.6÷1.2)·10 5...
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Mathematical Simulation of Osteodegenerative Process in Cervical Spine segment
Barsa, Pavel ; Maršík, František (advisor) ; Otáhal, Stanislav (referee) ; Hemza, Jan (referee)
Aim: The aim of following study is to simulate different types of loading on cervical vertebra and to identify if mechanical stress concentration in utmost positions corresponds with osteophytes localization find in clinical practice. The objective of our investigation is to develop a theoretical model that may elucidate clinical observation regarding the predilection site of bone remodeling. We will focus our attention on the physiological changes inside the cervical vertebral body. Methods: Real 3D-geometry of the fourth cervical vertebra had been made by commercially available system ATOS II. It is high-resolution measuring system using principles of optical triangulation. Such flexible optical measuring machine projects fringe patterns on the surface of selected object and the pattern is observed with two cameras. 3D coordinates for each camera pixel were calculated with high precision and a polygon mesh of the object's surface was further generated. ANSYS program has been used in the next step to calculate strains and stresses in each finite element of the virtual vertebra. Applied forces used in the experiment were of physiological magnitude and direction and mechanical stress distribution inside the vertebra has been calculated. Mechanical loading in neutral position has been characterized by...
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Mathematical Simulation of Osteodegenerative Process in Cervical Spine segment
Barsa, Pavel ; Maršík, František (advisor) ; Otáhal, Stanislav (referee) ; Hemza, Jan (referee)
Aim: The aim of following study is to simulate different types of loading on cervical vertebra and to identify if mechanical stress concentration in utmost positions corresponds with osteophytes localization find in clinical practice. The objective of our investigation is to develop a theoretical model that may elucidate clinical observation regarding the predilection site of bone remodeling. We will focus our attention on the physiological changes inside the cervical vertebral body. Methods: Real 3D-geometry of the fourth cervical vertebra had been made by commercially available system ATOS II. It is high-resolution measuring system using principles of optical triangulation. Such flexible optical measuring machine projects fringe patterns on the surface of selected object and the pattern is observed with two cameras. 3D coordinates for each camera pixel were calculated with high precision and a polygon mesh of the object's surface was further generated. ANSYS program has been used in the next step to calculate strains and stresses in each finite element of the virtual vertebra. Applied forces used in the experiment were of physiological magnitude and direction and mechanical stress distribution inside the vertebra has been calculated. Mechanical loading in neutral position has been characterized by...
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The biomechanics problems of thinwalled brain veins
Hemza, Jan ; Maršík, František (advisor) ; Otáhal, Jakub (referee) ; Vašků, Anna (referee)
Biomechanical material properties of the bridging brain veins are investigated experimentally (A Nikon light microscope was used for the histo-anatomical study and viskoelastic properties was measured on a MTS 858.2 Mini Bionix system ) and theoretically. The main goal of the developed theory was to formulate the biomechanical conditions (geometrical dimensions, viscoelastic properties of veins and blood fluid flow conditions) at which unstable behavior or even vein collapse can occur. The study of the geometry and topology of bridging veins was carried out by a magnetic resonance (Siemens Magnetom Symphony1,5 T) and a stereomicroscope (Nikon SMZ 1500) complemented with a digital camera (Nikon Coolpix E995) and Lucia Net software. From the biomechanical point of view, experimental findings can be summarized as follows: the existence of two types of venous brain systems; thin and thick wall veins with a one order difference in elastic modulus magnitude high sensitivity of the thin wall veins on the blood flow rate and extension or contraction on their structural stability the existence of continuing small wall vibration under physiological conditions Under small deformations conditions, the shear modulus was shown experimentally to be in the range (2÷4)·10 4 Pa with a Young modulus E= (0.6÷1.2)·10 5...
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