Human Biomechanics 2012: Collection of Abstracts

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Nov 5, 2012 - official conference of the Czech Society of Biomechanics. ... 13. Power produced by a muscle. Antonín Havránek, Martin Mayer . .... The head and cup of a ball-and-socket implant were analysed in seven positions according.
Institute of Physiology of the Academy of Sciences of the Czech Republic The Czech Society of Biomechanics

14th Conference on Human Biomechanics Collection of Abstracts

Třešť, November 5th - 7th 2012

Collection of abstracts of the 14th Conference on Human Biomechanics Human Biomechanics 2012 Třešť, Czech Republic November 5th - 7th 2012 c 2012 Vlasta Kofránková, Radim Michalec Compilation copyright ⃝ Editoris disclaims any responsibility for errors that may have been made by the authors. The data and opinions appearing in the articles are the responsibility of the contributors.

Preface Dear colleagues, It is my pleasure to welcome you at the traditional meeting 14th Human Biomechanics which will be held in the Castle of Třešť on 5th -7th November. Human Biomechanics 2012 is an International Conference of Biomechanics organized by the Institute of Physiology of the Academy of Sciences of the Czech Republic and the Czech Society of Biomechanics. The aim of the congress is to understand the state-of-the-art, exchange of experience, joint and establishment of cooperation among academic workers, company workers and scientific institutes. It is the official conference of the Czech Society of Biomechanics. In this abstract book you can find abstracts of all contributions including invited lectures. The abstract book is not indexed and if you are considering publishing of full-length paper a special issue of Bulletin of Applied Mechanics will be orginized by chief editor Assoc.Prof. Matej Daniel. Bulletin of Applied Mechanics (http://bulletin-am.cz/) is indexed in EBSCO, Google Scholar, DOAJ and is accepted as scientific peer-reviewed journal by the Czech Ministry of Education. The Bulletin of Applied Mechanics will not accept or publish manuscripts without prior peer review or papers published elsewhere. There will be a peer-review process of manuscripts by two or more independent referees who are conversant in the pertinent subject area. If submitted before November 1st, full text will be published in 2012 issue.

Jakub Otáhal Head of the Conference

Sponsors

http://www.kistler.com/

http://www.olympus.cz/

http://www.advanced-eng.cz/

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Conference Programme November 5th 8:15 - 11:45 11:30 12:30 12:45 15:30 16:00 18:00

Workshop of forensic biomechanics - only in Czech Lunch Opening Ceremony Section A + Section B Coffee Break Section A + Section B Dinner

November 6th 9:00 10:30 11:00 12:30 13:30 - 18:00 19:00

Section A + Section B Coffee Break Section A + Section B Lunch Trip to Telč (UNESCO) or Jihlava Gala Dinner

November 7th 9:00 10:30 11:00 12:30 12:45 - 18:00 15:30

Section A + Section B Coffee Break Section A + Section B Closing Ceremony Lunch Departure

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Hotel Plan

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Contents Preface

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Conference Programme

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Hotel Plan

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Abstracts Evaluation of contact pressure by using Pressurex films Michal Ackermann, Lukáš Čapek, Petr Henyš, Cyril Dody . . . . . . . . . . . . . . . . Analysis of the force needed for the closure of the sternum after median sternotomy Maxime Billon, Lukáš Čapek, Martin Kaláb, Petr Henyš, Petr Hájek . . . . . . . . . Insight into tensile fatigue damage of UHMWPE with an aid of experimental and computational Small punch testing Tomáš Bouda, Pavel Růžička, Radek Sedláček, Miroslav Šlouf, Svatava Konvičková . . Musculoskeletal modeling of the mandible movement, muscle forces, and joint forces with Opensim software Michala Čadová . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Effect of patient-specific model scaling on hip joint reaction force in one-legged stance– study of 368 hips Matej Daniel, Jana Hornová, Aleš Iglič, Veronika Kralj-Iglič . . . . . . . . . . . . . . . Biomechanical effect on bone formation during lengthening of long bones František Denk, Miroslav Petrtýl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Resonance meters for viscoelasticity measurement Stanislav Doubal, Petr Klemera, Monika Kucharova, Jan Doubal . . . . . . . . . . . . Whiplash - head injury criterion and neck muscle activation during deceleration Ondrej Fanta, Petr Kubovy, Dan Hadraba, Frantisek Lopot, Karel Jelen . . . . . . . . Mechanical properties of the NiTitex composite Eva Gultová , Lukáš Horný, Hynek Chlup, Rudolf Žitný . . . . . . . . . . . . . . . . . Power produced by a muscle Antonín Havránek, Martin Mayer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The biomechanic quality of dura mater correlating histology 3D-findings Jan Hemza . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Comparison of hip joint reaction forces calculated by OpenSim with the experimental data Jana Hornová, Matěj Daniel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rheological and geometric changes in the knee meniscus in response to dynamic mechanical stress Lenka Horňáková, Štursa Pavel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Effect of Ion Concentration Changes in T-tubules on Membrane Currents and Intracellular Ca2+ Transient in a Model of Human Ventricular Cardiomyocyte Dana Hrabcová, Michal Pásek, Jiří Šimurda, Georges Christé . . . . . . . . . . . . . . Identification of relaxation parameter of a small latex tube David Hromádka, Hynek Chlup, Rudolf Žitný . . . . . . . . . . . . . . . . . . . . . . . Scaling of Human Body Model L. Hynčík, H. Čechová, L. Kovář . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The possibilities of change registration of mechanical properties of human axial system as a result of hypo-hyperkinetic strain regime K.Kloučková, J. Zeman, Š. Panská, K. Jelen . . . . . . . . . . . . . . . . . . . . . . . . Finite element model of the operative treatment of pelvic ring fracture Magdaléna Jansová, Jiří Křen, Tomáš Pavelka, Martin Salášek, Drahomíra Weisová . .

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Biomechanical gait analysis in professional ballet dancers M. Janura, L. Teplá, M. Procházková, Z. Svoboda . . . . . . . . . . . . . . . . . . . . Kinematics of the cervical-thoracic spine and the shoulder girdle Ivana Jelínková . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Osteons response to mechanical effects Aleš Jíra, Miroslav Petrtýl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dental implants - critical review Alice Kapková, Aleš Jíra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Estimation of Mechanical Properties of the Lamella of a Bone’s Osteon Radim Korsa, Tomáš Mareš . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . What affects vascular branching mechanics? J. Kronek, T. Adámek, L. Horný, H. Chlup, R. Žitný . . . . . . . . . . . . . . . . . . . Human knee joint osteoarthritis: Influence of SYSADOA group chemicals Petr Kubový, Lucie Menšíková, Eva Kůrková, František Lopot, Karel Jelen . . . . . . Modelling of the normal and pathological bile flow in the biliary system A.Kuchumov, Yu.Nyashin, V.Samarcev, V.Gavrilov . . . . . . . . . . . . . . . . . . . . Active Mechanism of Foot Arch Maintenance Radim Michalec, Petr Novák, Stanislav Valenta, Jakub Otáhal . . . . . . . . . . . . . A jig for an assessment of anisotropic mechanical properties of bone lamella Jaroslav Lukeš, Tomáš Frantík, Josef Šepitka . . . . . . . . . . . . . . . . . . . . . . . Changes in intracranial pressure during biomechanical action on the lungs Martin Mayer, Antonín Havránek, Karel Jelen . . . . . . . . . . . . . . . . . . . . . . Mechanical response of human skin on dynamical loading Kuchařová Monika, Ďoubal Stanislav, Klemera Petr . . . . . . . . . . . . . . . . . . . Alterations of evoked electromyographic responses by passive stretch or shortening of the skeletal muscle Jakub Otáhal, Ondřej Borský, Tereza Světlíková, Petr Kubový . . . . . . . . . . . . . Comparative analysis of the spinal kinematics before and after implantation of artificial disc Martin Otáhal, Jiří Kuželka, Petr Heralt, Lukáš Jiran, Miloš Moravec, Petr Kubový . The foot dynamics analysis in vertical jump Barbora Pánková, Petr Kubový, Karel Jelen . . . . . . . . . . . . . . . . . . . . . . . . A new quantitative description of intracellular and t-tubular Ca2+ dynamics in a model of the rat ventricular cardiomyocyte Michal Pásek, Jiří Šimurda, Clive H. Orchard . . . . . . . . . . . . . . . . . . . . . . . A possible role of electrostatic interactions in a process of osteointegration Šárka Perutková, Aleš Iglič . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Numerical model of the cardiovascular system with the cavopulmonary connection S. Převorovská , F. Maršík , V. Chaloupecký . . . . . . . . . . . . . . . . . . . . . . . . EMG signal decomposition methods and their possible usage in active prothesis Antonín Pošusta, Vlasta Kofránková Jakub Otáhal . . . . . . . . . . . . . . . . . . . . Simulation tools for analyses of biomechanical injury criteria Hynek Purš . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Effectiveness of preventive and curative ergonomic interventions in work environment David Ravnik . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Modelling of blood perfusion simulation of dynamic CTP Eduard Rohan, Vladimír Lukeš, Alena Jonášová, Ondřej Bublík . . . . . . . . . . . . Modelling of the Smooth muscle and Cajal’s Cells Communication in the Bladder Wall Josef Rosenberg, Milan Štengl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The Influence of Steam Sterilization Processes on the Micromechanical Properties of Polyamide Fiber-Reinforced PDMS Composites for Medical Device Applications Radek Sedláček, Tomáš Suchý, Miroslav Sochor, Karel Balík, Zbyněk Sucharda, Josef Šepitka . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Concept of the knee joint replacement with reference to new scientific knowledge Michal Síbr, Daniel Bodlák, Aleš Lerach, František Denk . . . . . . . . . . . . . . . . . Hair material parameters’ determination by free oscillations method Marie Skřontová, Lucie Šimková, Karel Jelen, Josef Zeman . . . . . . . . . . . . . . . Evaluation of Mechanical Properties of PDLLACollagen Nanocomposite at Micro-Scale Tomáš Suchý, Šárka Rýglová, Zbyněk Sucharda, Karel Balík, Josef Šepitka, Jaroslav Lukeš . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The influence of functional strength of lower limbs and balance on foot pressure distribution during gait in subjects with cerebral palsy and intellectual disability Zdenek Svoboda, Miroslav Janura . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nanoindentation of Histological Sections of Intervertebral Disc-Vertebral Body interface Josef Šepitka, Jaroslav Lukeš, Libor Staněk, Jan Řezníček . . . . . . . . . . . . . . . . Dependence of the Young’s modulus in tension and in shear in case of a human hair Lucie Šimková, Marie Skřontová, Karel Jelen, Josef Zeman . . . . . . . . . . . . . . . The influence of trunk kinematics and respiratory parameters M. Šorfová, E. Slawiková, P. Kubový, T. Dolanská . . . . . . . . . . . . . . . . . . . . Influence of ventilation to intracranial presure (ICP) in severe cranial trauma Petr Vaněk, Zbyšek Štěpánik, Jakub Otáhal . . . . . . . . . . . . . . . . . . . . . . . . The Effect of Load on the Accuracy and Kinematic Profile of a Simple Forearm Movement F. Vaverka, D. Jandačka, R. Farana, D. Zahradník . . . . . . . . . . . . . . . . . . . . Structural constitutive model of human vena cava reflecting collagen orientation and waviness Jan Veselý, Lukáš Horný, Hynek Chlup, Rudolf Žitný, Tomáš Adámek . . . . . . . . .

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Abstracts Abstracts are sorted according surname of the first author.

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Evaluation of contact pressure by using Pressurex films Michal Ackermann, Lukáš Čapek, Petr Henyš , Cyril Dody Arthritis of trapeziometacarpal (TMC) joint at the base of the thumb is a frequent disease, which causes annoying symptoms which can impair both strength and function of the hand. The condition occurs most commonly in postmenopausal women, over the age of fifty. The most common TMC implant is a ball-and-socket implant, which is composed of three parts: stem, head and cup. The most serious problem of these implants is the wearing. The wearing is strongly influenced by distribution of contact pressure between implants’ parts. Nowadays, the evaluation of contact pressure is mostly performed by support of a finite element analyses, nevertheless evaluation of these results is usually neglected. The aim of this contribution is to evaluate the contact pressure, using finite element method and Pressurex films. The head and cup of a ball-and-socket implant were analysed in seven positions according to the movement of this implant. In the first approach, finite element method was used. The distribution and maximal values of contact pressure were evaluated. In the second step, pressure films were used. The Pressurex film, cut into one centimetre diameter circle, was inserted between the two components of the implant and then pushed against each other to contact under the load of 100 N. This process was repeated for seven angles: 0, 15, 20, 30, 35, 45, 55◦ by modifying the position of the selector. The results of experimental method support the FEA method well about the fact, that the contact pressure is spread in a very disadvantageous way over the contact area between the head and the cup of the implant. Moreover, experimental results, when the selector is tilted to the extreme value, tend to get closer to FEA ones, with the presence of the strip around the inner surface.

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Analysis of the force needed for the closure of the sternum after median sternotomy Maxime Billon, Lukáš Čapek, Martin Kaláb, Petr Henyš, Petr Hájek Technical University of Liberec, Czech Republic

Abstract summary The median sternotomy consists in opening the rib cage with a sagittal section following the median plane during cardiac surgery. The common sternal closure complication is the inability to maintain stabilization of the sternotomy closure site. Wound dehiscence, purulent drainage, and sternal instability are indicative of bacterial contamination in the face of sternal separation and instability can then progress to deep sternal wound infection and mediastinitis. A wound infection following median sternotomy represents a serious problem in open heart surgery. It occurs in approximately 0.8-8% of all operations and contributes significantly to morbidity and mortality. The aim of this contribution was to analyze the force needed for the closure of the rib cage after median sternotomy. The first estimation was done on one rib, where analytical and numerical analysis was done. In the second step a half finite element model with rib cage and a half of sternum was built. The value of the closing force found was found 27.5 N in case of whole 3D FEM model and 55 N in case of analytical approach. We could make a hypothesis that the global reaction force was between 30 N and 60 N. But the value of this global reaction force depends on the age, the gender of each body. That is due to the calcification and the ossification of the cartilage which appear with the age. So more the body is old more the global reaction force would be higher. The next study will be aimed to the analyses of the length of the costal cartilage especially on the first rib depending on the age and apply this length on our 3D model to analyze by finite element method the global reaction force after a median sternotomy.

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Insight into tensile fatigue damage of UHMWPE with an aid of experimental and computational Small punch testing Tomáš Bouda, Pavel Růžička, Radek Sedláček, Miroslav Šlouf, Svatava Konvičková Czech Technical University in Prague, Czech Republic

Abstract Summary The objective of this work was an evaluation of mechanical fatigue properties of a semicrystalline polymer ultra-high molecular weight polyethylene (UHMWPE) with use of ”Small Punch Test”. Basic procedure of the static Small Punch Test is described in ASTM standard F2183-02 but a modified procedure based on Villarraga et al. (2003) was employed. Two different approaches were applied. In a first step primary fatigue characteristic were gained by force-controlled experimental testing and in a second step finite element analyses (FEA) with very similar testing protocol were accomplished. FEAs were used to find interpretations for experimentally observed phenomena because evolution of stress/strain state in a specimen was impossible to evaluate in an analytic way. To be able to simulate complex constitutive response of the UHMWPE a Hybrid constitutive model for UHMWPE was utilized (Bergström 2004). Promising results bringing insight into tensile mode of fatigue damage of UHMWPE were gained.

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Musculoskeletal modeling of the mandible movement, muscle forces, and joint forces with Opensim software Michala Čadová Czech Technical University in Prague, Czech Republic

Abstract Summary Dynamic mathematical modeling is an invaluable method to help understand the biomechanics of the anatomically and functionally complex masticatory system. Musculoskeletal models provide insight into variables which are difficult, or even impossible, to measure directly; such as joint loads and muscle forces. Individual input parameters can be modified easily to understand their influence on the function. The geometry of the presented model is based on the generic model (six degree of freedom) which is part of the installation package of the software used (Opensim, Delp et. al 2007). The model consists of the skull, mandible, vertebral column, rib cage, clavicle and scapula. Movements are provided by four muscles (temporalis, masseter, pterygoid, and digastric). Generic Hill-type muscle model is used. The objective of this work is to present and validate a rigid body musculoskeletal model of the ”mandible-skull” system for different types of mandible movement tasks. Kinematics of the mandible was recorded by ”Optis” motion capture system (Dental Clinic, University of Zurich, Switzerland), EMG signal, for validation purposes, was recorded by means of portable two-channel electromyographic recorder (Dental Clinic, University of Zurich, Switzerland), and biting force using one-dimensional piezoelectric force transduce (type 9001, Kistler AG, CH-8408 Winterthur, Switzerland). Scaling of the generic model and assessment of the muscle forces and joint reaction forces is performed using inverse kinematics and inverse dynamics method.

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Effect of patient-specific model scaling on hip joint reaction force in one-legged stance– study of 368 hips Matěj Daniel, Jana Hornová, Aleš Iglič, Veronika Kralj-Iglič Matěj Daniel, Faculty of Mechanical Engineering, Czech Technical Univer- sity in Prague, Czech Republic Jana Hornová, Faculty of Mechanical Engineering, Czech Technical Univer- sity in Prague, Czech Republic Aleš Iglič, Faculty of Electrical Engineering, University of Ljubljana, Slove- nia Veronika Kralj-Iglič, Medical Faculty, University of Ljubljana, Slovenia

Abstract Summary Estimation of hip joint loading is fundamental for understanding joint function, injury and disease. As the measurement of the forces acting in the hip joint is technically complex and invasive, large majority of studies estimate hip force by a mathematical models. Recent studies have shown that the generic scaling fails to predict accurate muscle-tendon lengths, muscle moment arms, and muscle forces in comparison to modeling of an individual hip based on geometrical parameters obtained from MR scans. It was suggested that scaling by geometrical parameters obtained from standard antero-posterior radiograms could improve the accuracy of determination of the hip joint reaction force. This study analyzes the effect of three different scaling methods on the calculated hip joint reaction force subject to patient-specific geometry. Geometrical parameters were obtained from standard anteroposterior radiograms of 308 hips while the force was calculated by a previously validated three dimensional model of the onelegged stance. It was found that including patient-specific geometry in more detail considerably affects the hip joint reaction force and extensions of the iliac bone and greater trochanter, are not proportional to the overall size of the hip bone. To improve estimation of the hip joint reaction force in an individual, determination of hip and pelvis geometrical parameters should be included in the scaling method.

Purpose Estimation of hip joint loading is fundamental for understanding joint function, injury and disease. As the measurement of the forces act- ing in the hip joint is technically complex and invasive, large majority of studies estimate hip force by a mathematical models. Recent studies have shown that the generic scaling fails to predict accurate muscle- tendon lengths, muscle moment arms, and muscle forces in comparison to modeling of an individual hip based on geometrical parameters ob- tained from MR scans. It was suggested that scaling by geometrical parameters obtained from standard antero-posterior radiograms could improve the accuracy of determination of the hip joint reaction force. This study analyzes the effect of three different scaling methods on the calculated hip joint reaction force subject to patientspecific geometry.

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Methods Geometrical parameters were obtained from standard anteropos- terior radiograms of 308 hips while the force was calculated by a pre- viously validated three dimensional model of the one-legged stance.

Results It was found that including patient-specific geometry in more detail considerably affects the hip joint reaction force as the extensions of the iliac bone and greater trochanter, are not proportional to the overall size of the hip bone.

Conclusions To improve estimation of the hip joint reaction force in an indi- vidual, determination of hip and pelvis geometrical parameters should be included in the scaling method.

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Biomechanical effect on bone formation during lengthening of long bones František Denk1 , Miroslav Petrtýl1 1

Ing. arch. et Ing. František Denk; Laboratory of Biomechanics and Biomaterial engineering, Department of mechanics, Faculty of Civil Engineering, CTU in Prague; Thákurova 7, 160 00, Prague, Czech republic; [email protected] 2 Prof.

Ing. Miroslav Petrtýl, DrSc.; Laboratory of Biomechanics and Biomaterial engineering, Department of mechanics, Faculty of Civil Engineering, CTU in Prague; Thákurova 7, 160 00, Prague, Czech republic; [email protected]

Abstract Summary The lengthening of long bones in children using the traction osteogenesis method is performed by the gradual distraction of the opposite ends of bone fragments. Mechanical factors are of major importance for the development of the callus between two successive elongations, as well as during the time of its consolidation and modelling. New designed external fixator accelerates the healing process and stimulates the formation of callus and subsequent ossification. The limitation of pain during the actual lengthening process such as by selecting the appropriate size and frequency of distraction steps together with dynamic effect is also equally important. The lengthening of long bones in children using the traction osteogenesis method is performed by the gradual stretching of the callus of the healing bone tissue. Mechanical factors are of major importance for the development of the callus between two successive elongations, as well as during the time of its consolidation and modelling. Changes in stresses and deformations initiated by external force and moment effects very efficiently regulate the velocity of healing, the formation of bearing structures in the tissue and, last, but not least, the development of adequate elastic and viscoelastic properties in the tissue. We have further methodologically extended Ilizarov’s conditions by adding electronically regulated elongation consisting in a very careful gradual lengthening of the ends of bone fragments by 0.25 mm which takes place every 4 hours. Successively, during 8 hours, the tissues were kept in a quiescent state. With regard to the acceleration of healing, the tissues were loaded with cyclic deformations with amplitudes of oscillations of 0.1 mm during 4 x 4 hours, always for a period of 10 minutes. After each cyclic loading the healing tissues were kept in a quiescent state for a period of 50 minutes. The new methodology of traction neo-osteogenesis is biomechanically initiated by the action of its combined loading, i.e. by constant tensile stress and short-term repetitive cyclic load acting perpendicular to the plane of the osteotomy. After the initial relatively quiescent phase, the biosynthesis of new tissue, the proliferation and differentiation of cells is dynamically in progress, in correlations with gradual lengthening with low magnitudes of amplitudes of 240 µm. The intensity of the metabolic activity in the cells highly depends on their supply with blood and on programmed functional loading of the lengthened proximity. The designed electronically regulated lengthener speeds up desmogenic ossification. Its construction allows imposing tensile microdeformations and harmonically varied forces with low amplitudes to tissues. These microdeformations and oscillation frequencies are controlled by means of an electronic unit.

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References [1] Bellemore, M.C. Advances in limb lengthening. SterilizAust, 12, 1993,p. 20-21. [2] Frost H.M. The Utah paradigma of skeletal physiology. Vol. 1. Bone and Bones and Associated Problems, ISMNI, Greece , 2004, 427 pp. [3] Illizarov G.A. Deviatov A.A. Operative elongation of the leg with simultaneous correction of the deformities, Ortop. Travmatol Protez, 30; 0969, pp.32-37. [4] Ilizarov G.A. Basic principles of transosseous compression and distraction osteosynthesis. Ortop. Traum. Trot.,32,1971, pp. 7-15.

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Resonance meters for viscoelasticity measurement Stanislav Doubal, Petr Klemera, Monika Kucharova, Jan Doubal Faculty of Pharmacy, Charles University, Czech Republic

Abstract Summary Resonance meters for viscoelasticity measurement are result of joint development on Department of Biophysics of Faculty of Pharmacy and firm DELTER. Measurements are based on resonance principle. Apparatuses measure frequency and damping of self-oscillations of the system consisting of a sample and the moving part of meter. Basic viscoelastic characteristics of the sample are calculated of from these parameters and from the shape of the sample. Apparatuses are equipped with computer and software that enable quick and accurate determination of dynamic stiffness, complex modulus of elasticity (loss and storage moduli), time constants of transient responses and mechanical impedance of the sample. Measurements are possible in various frequencies of loading and in different static pre loadings. Frequencies and pre loadings may be adjusted independently. Software also calculates modulus of elasticity and viscosity for Voigt’s model.

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Whiplash - head injury criterion and neck muscle activation during deceleration Ondřej Fanta∗ , Petr Kubový, Dan Hadraba, František Lopot, Karel Jelen ∗ Charles

University in Prague, Faculty of Physical Education and Sport, Department of Anatomy and Biomechanics,Czech Republic, e-mail: [email protected]

Abstract Summary The aim of this study is to monitor and describe physically the natural response of the head to rapid deceleration. The methodology of using an impact simulator was adopted for simulating a load which is applied to the passengers wearing a seat belt in a head-on collision of a car at the speed of 30 km/h. Furthermore, a series of comparative tests of two versions (impact with and without a blindfold) were conducted to determine the influence of vision, consciousness on risk and seriousness of trauma and the results were compared with the measurements on a dummy. Considering head injuries that occur while rapid decelerating, at low speed there is no direct contact between the head and a solid obstacle (car interior), thus no head injuries are listed. The head acceleration in three axes and the neck muscle activity (EMG) were scanned. The values of the head acceleration were obtained through the accelerometers fixed on the participants’ forehead; furthermore, the acceleration on the impact desk was measured. The whole scenery of the impact was even monitored by Qualysis and a digital video camera which enabled slow motion recording. The HIC (Head Injury Criterion) and 3ms criterion were employed to compare the seriousness of the head injury.

Introduction The methodology of using an impact simulator was adopted for simulating a load which is applied to the passengers wearing a seat belt in a head-on collision of a car at the speed of 30 km/h. Considering head injuries that occur while rapid decelerating, at low speed there is no direct contact between the head and a solid obstacle, thus no head injuries are listed.

Methods The experiment was launched on eight participants who were measured during impact at the simulator. The head acceleration in three axes and the neck muscle activity (EMG) were scanned. Firstly each participant underwent the impact blinded and then again without a blindfold. The values of the head acceleration were obtained through the accelerometers fixed on the participants’ forehead; furthermore, the acceleration on the impact desk was measured. The HIC (Head Injury Criterion) and 3ms criterion were employed to compare the seriousness of the head injury.

Results The values of recorded accelerations in three axes were converted to the resultant acceleration of the head and the values of the HIC, 3ms criterion, and the maximum acceleration were computed. At the same time, acceleration of the simulator was measured to compare it with the magnitude of individual impacts. The summarized results are in Figure 1.

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Figure .1: The values comparing the results between the dummy and the participants (with and without eyes).

Discussion According to the results from the accelerometer located on the simulator the magnitudes of the impacts were equal (mean 25.2g) for all the tests. The statistics show a positive relation between the blindfold and the maximum head acceleration (the head acceleration is higher in the second test while wearing a blindfold). The mean decrease of the maximum value between the two tests was 3.9g (38.3 m/s2), which is equal to 32%. On the other hand the significant effect (p value .05) on the HIC36 was not evidenced in the tests, however, the HIC36 was lowered by 1.7 (29%) while wearing a blindfold. This project is supported by GAUK 111310, GAČR P 407/10/1624 and SVV-2012-265 603

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Mechanical properties of the NiTitex composite Eva Gultová, Lukáš Horný, Hynek Chlup, Rudolf Žitný Faculty of Mechanical Engineering, CTU in Prague, Technická 4, 166 07 Prague 6, Czech Republic

Abstract Summary Hibrid composites reinforced by superelastic SMA (shape memory alloy) wires show potential for application in different areas, e.g. aerospace industry, automotive applications and as well in medical applications. NiTinol as a representative of SMA is attractive for its superelasticity, shape memory and biocompatibility. Our report analyzes mechanical response of the silicon-textile (SilTex) composite which is reinforced by Nitinol wires (NiTiTex). In order to determine individual contributions of particular components to the mechanical response of the composite, specimens of SilTex, NiTiTex and NiTinol wire were subjected to uniaxial loading and unloading. It was found out that the implantation of the NiTinol wire into silicon-textile matrix significantly influences mechanical properties of the composite. The testing of the specimens proved that the NiTiTex (assumed as homogenized sample) replicates mechanical response of the NiTinol wire, while SilTex composite demonstrates rather polymerlike response. Two substantial phases were observed during loading of both NiTinol wire and NiTiTex: elastic phase followed by superelastic one, which is typical by increase of the deformation without rise in load. In order to find out, whether it is possible to model the NiTiTex composite as homogenized material, simple elastoplastic model was applied.

Purpose Hibrid composites reinforced by superelastic SMA (shape memory alloy) wires show potential for application in different areas, e.g. aerospace industry, automotive applications and as well in medical applications. NiTinol as a representative of SMA is attractive for its superelasticity, shape memory and biocompatibility. Our report analyzes mechanical response of the silicontextile (SilTex) composite which is reinforced by Nitinol wires (NiTiTex).

Methods The matrix of the composite is made of the textile fabric embedded into the silicon which is reinforced by NiTinol wires of the diameter 0.075 mm. The material is fabricated by overlapping two thin layers, each with unidirectional reinforcement, resulting in a presence of two mutually orthogonal directions of NiTi wires within the plane of the final structure. In order to compare mechanical response of the constituents and the composite, uniaxial tensile tests were performed on the Messphysic testing machine. Two samples of each component (silicon-textile matrix, NiTinol wire and NiTiTex composite) underwent simple tension loading and unloading. Deformation of the tested samples was evaluated by video-extensometer, which is built-in testing machine. Mechanical response of the NiTiTex composite was described using a simple rheological model which consists of parallel connection of the elastic (representing silicon-textile matrix) and

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ideal plastic (representing NiTinol wires) material. The model of ideal plastic material was adopted to capture constant stress at phase transformation.

Results Material parameter describing rheological properties of the homogenized material were determined from the uniaxial tensile tests of individual components. During the loading, the NiTiTex composite replicated mechanical response of the NiTinol wire. First elastic phase was followed by superelastic plateau, as well as the transformation appears at ”transformation” strain ( 0.01). The simple ideal plastic rheological model was applied in order to model mechanical response of the composite, which was assumed as the homogenized structure reflecting characteristics of individual components. While reference cross-section area of each sample was measured with standard deviation, the model nominal stress was computed for the medium, maximum and minimum area (Fig.1).

Figure .1: Uniaxial loading of the NiTiTex composite. The experimental curve (blue curve) is evaluated as the average of two measurements. Error bars include both measurements error and inter-sample variance. Model curve is evaluated for the medium, maximum and minimum cross-section.

Conclusion The testing of the specimens proved that the NiTiTex (assumed as homogenized sample) replicates mechanical response of the NiTinol wire, while SilTex composite demonstrates rather

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polymer-like response. The model suggested as the parallel connection of the elastic (matrix) and ideal plastic (wire) element was able only to simulate individual phases typical for loading of superelastic material, while quantitative coincidence did not occurred. One explanation could be in fact, that model does not take into account the adhesion between NiTinol wires and silicon-textile matrix, which has essential impact on the mechanical behaviour. This work has been supported by Grant Agency of the Czech Technical University in Prague SGS10/247/OHK2/3T/12 and Czech Science Foundation P108/10/1296.

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Power produced by a muscle Antonín Havránek1 , Martin Mayer2 1

Charles University, Faculty of Mathematics and Physics, V Holešovičkách 2, 18000 Praha 8, Chech Republic, e-mail: antonin.havranek@mff.cuni.cz 2 Na Homolce Hospital, Prague, Czech Republic

Purpose In our previous works 1, 2, 3 we have derived the equation p=

1 2 σ η

(.1)

from which the power density p produced in a given place of a muscle can be calculated from the stress σ transferred via the place and the muscle activity 1/η in the place. The muscle activity depends on the quantity of myosin-actin pairs in the place and on the state of the muscle, if it is relaxed or tired. This activity is large in soft parts of a muscle and low in sinews. The power P produced in the whole muscle is obtained by integrating the power density via the volume of the muscle. The advantage of the equation is that it enables to calculate the power of the muscle or of the system of muscles only by mechanical means, The second advantage is that as the power produced by a muscle is calculated from the stress transported via the muscle and not from its movement the work done when we feel that some energy is consumed (we are working) and crude mechanical models say that we are doing nothing. Typical examples of such a performance is carrying a heavy suitcase via a long horizontal road to a railway station or holding the beer-glass in the stretched arm (see Figure 1).

Methods Viscoelastic Maxwell model (right hand side of Figure 1) is used to describe the energy input within a muscle. In the left hand side of Fig. 1 the beer glass held by a man is pictured to visualize the situation modelled by the Maxwell scheme.

Figure .1: A man holding the glass of beer and the Maxwell model used for rheology description of the act.

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The viscous element η of the model in classical materials describes energy losses. In our model it is used to describe the energy input to a muscle as in biomaterials also energy input is possible by feeding it (ATP → ADP process). By feeding the muscle the man prevents the fall of the beer and he is able to do it until his arm muscle is tired. In the model transcription the fed piston η is able to compensate the fall of the beer (the force denoted F in the Figure) till the muscle activity 1/η can reach its critical value necessary to the fall. These are the ideas from which the equation (1) has been derived (for more details see [1]).

Results The equation (1) can be used to calculate the power input necessary for doing some activities. E.g. for holding a beer we have calculated that the necessary power input is 25 W. In the case of shot putting the power P produced by the athlete can be derived from the throw length and the time of the athlet’s activity. If we estimate the volume of muscles engaged in the throw we may derived the mean activity 1/η of the muscles engaged in the throw. Using crude approximations we have got the order of magnitude value for the mean muscle 1/η = 10−4 1/Pa.s in this case (for more details see [2]).

Conclusion An equation enabling to calculate the power output of a muscle only by mechanical means has been derived. It can be used to calculate the power input to muscles in sporting performances as well as in the cases like is the transporting a heavy suitcase via a horizontal road or holding a glass of beer where crude mechanics says that we are doing nothing.

References [1] Havránek A, Bulletin of Applied Mech. 5(17), p. 1-5, 2009 [2] Havránek A, Calculation of the energy produced in muscles. In: Human Bimechanics 2010, Sychrov. p. 356-361. Technical University of Liberec, Liberec 2010 [3] Havranek A, Mayer M, Jelen K, Proceedings - ISB 2011, Brussels

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The biomechanic quality of dura mater correlating histology 3D-findings Jan Hemza

Abstract Summary In literature there is only one study of biomechanic quality of dura mater - Melvin 1975. Melvin described the technic of study in different plane, but in paper published only one number of biomechanic quality (6-8.103 psi = 0,414- 0,552.106N/m2). The Melvin biomechanic of quality of dura mater was used in all of biomechanic model of study traumatic attack, modelating of different intractranial probléme later. Our study the used the technic of biomechanic study of dura mater in 2 mutually perpendicular plane. The biomechanic study is correlated with histological study, when dura mater is studed in 3 perpendicular histology plane - 3D study. n the different part of intracranium the dura mater analyses different biomechanical characteristic. On the convexity and anterior fossa the dura mater have different biomechanical characteristics in coronal and sagital way. (Young modulus - N/m3 .109- convexity: coronal 0,241, sagital 0,208, anterior skull base fossa: coronal 0,576, sagital 0,410 -(p< 0,1), posterior skull base fossa: coronal 0,229, sagital 0,227, middle fossa: 0,536, median part of skull base 0,563; volume modulus elasticity - N/m3 .109 - convexity: coronal 0,269, sagital 0,214 (p