National Repository of Grey Literature 68 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Simulation and experimental evaluation of the effects of small ammunition bullets entering a bulletproof vest
Billich, Richard ; Jelen, Karel (advisor) ; Otáhal, Jakub (referee) ; Chlup, Hynek (referee)
Title: Simulation and experimental evaluation of the effects of small ammunition bullets entering a bulletproof vest Objectives: The main objectives of the study were: parameterization of the wounding effects of bulletson artificial materials, quantification of bullet impacts using international and experimental gunshot wounding criteria, parameterization of the mechanical characteristics of polymer fibers used in bulletproof vests, objectification of the deformation effects of missiles on soft biological tissues and creating a simplified analysis of ballistic missile interaction. Methods: In this study, experiments were performed on two artificial materials: food gelatine and glycerine soap. Calculated values and individual parameters are reported for 9 mm weapon systems. The experiments were performed in a ballistic test laboratory under standardized conditions. Data processing and parameterization of shape changes were performed using computed tomography (CT), micro-CT,ultrasound elastography and 3D scanning. Other devices used were infrared vibration spectroscopy and high-speed camera. We used the collected datato create analytical relations describing the mechanical effects ofthe material under a bulletproof vest.. Results: The area of greatest impact for the ammunition was 1.48 - 1.6 times...
Identification of the cervical spine's meniscoids by MRI before and after aplication of manual therapy
Píglová, Tereza ; Jelen, Karel (advisor) ; Tlapáková, Eva (referee) ; Vacek, Jan (referee)
Introduction The joint dysfunction of the spine in the sense of functional blockade is connected with corresponding painful condition, reflex contraction of the surrounding muscles and restriction of mobility in the spinal segment. Joint block has its mechanical context, which need not be accompanied by a structural disturbance but it's affecting the biomechanical properties of the spine. Several theories exist how the joints become restricted. Scientific evidence highly supports the meniscoid entrapment theory. Purposes The aim of the study was to identify the meniscoids of the cervical spine using in- vivo MRI imaging and to determine their potential role in the development of functional joint blocks of the axial system (AS). Another objective was to find out how the articular blocks affect the rheological properties of the spine by the Transfer Vibration through the Spine (TVS) method. Patient sample The MRI study was conducted on a research file of 12 subjects - two anatomical preparations and ten in vivo. Two subjects were examined in TVS experiment. Methodology Two anatomical preparations were investigated on MRI to find the appropriate sequence for imaging of meniscoids, three subjects for identification of meniscoids in vivo. Seven subjects underwent initial investigation, manipulation of...
Biomechanical response of selected structures of the knee joint to mechanical loads
Horňáková, Lenka ; Jelen, Karel (advisor) ; Navrátil, Leoš (referee) ; Mlynárik, Vladimír (referee)
Title: Biomechanical response of the knee meniscus to the axial loads Work Title: The quantification of the structural changes in deep layer of the knee meniscus using the standardized axial loading Purpose: Due to the internal structure of the knee joint, the ability to characterize and quantify the dynamic response of the meniscal tissue directly in vivo is highly problematic. The main purpose of this study was to investigate the behavior of the meniscus under loading conditions, using parametric MR imaging. Methods: Subjects with no history of knee pain or meniscal problems were included in the study (mean age 27.8 ± 1.3 years). To obtain values of relaxation times T2* in the meniscus, the vTE sequence was used with 10 echoes ranging from 0.8 to 10.1 ms. This has resulted in minimizing the echo time, which is an advantage when differentiating meniscal tissue from surrounding components. First of all, an unloaded limb was scanned and immediately after, the limb loaded half of the person's weight was measured repeatedly in 4 consecutive scans. A custom - made diamagnetic apparatus was developed to simulate stress conditions on the lower limb in a conventional MR scanner. At each 6:10 min measurement, the knee joint was scanned in 64 sections, each image displaying a 1.3 mm section.The two -...
The effect of intensity of voluntary isometric contraction on rheological characteristics of skeletal muscle tissue in vivo, in situ
Kopecká, Barbora ; Bittner, Václav (advisor) ; Jelen, Karel (referee)
Title: The effect of intensity of voluntary isometric contraction on rheological characteristics of skeletal muscle tissue in vivo, in situ Objectives: The main aim of this study is to determine the effect of intensity of isometric voluntary contraction of skeletal muscle on its viscoelastic characteristics. The work also aims to contribute to the verification of myotonometer as an objective diagnostic instrument and compares it to known methods for evaluation of muscle tone, or its partial characteristics. Methods: We used myotonometer - utility model 29456 for evaluation of changes of stiffness and viscous behavior of skeletal muscle in vivo, in situ in 20 healthy volunteers. The values were compared during 0%, 20%, 35% and 50% of maximal strength of isometric contraction of finger flexors, controlled by hand-held dynamometer. Results: We concluded that both stiffness and viscous behavior of skeletal muscle increases with higher intensity of isometric voluntary contraction. Keywords: myotonometer, skeletal muscle, viscous behavior, stiffness, muscle tone
Motion analysis of lower extremity during squatting.
Varga, Pavel ; Vilímek, Miloslav (advisor) ; Jelen, Karel (referee)
Title: Motion analysis of lower extermity during squatting Aims: The aim of the thesis is to compare the squat without and with external load in a group of people who work under professional guidance and have experience with this movement, contrary to the people of the common population. Another objective will be the compasion this movement among men and women of the common population. In the theoretical part, the main objective is to describe the basic characteristic of the squat, describe the kinesiological and biomechanical findings and the risks of this movement on the locomotive apparatus. The experimental part will focus on the observation of the determined kinematic parameters of squats and their comparison in the mentioned set of persons. The results of the work should clarify the possible side effects of the squat. Methods: Kinematic analysis will be performed using Qualisys instrumentation. Infrared cameras accurately record and further perform a motion action through passive or active reflection markers. Data from the device will be processed in Microsoft Office Excel software and further evaluated statistically. Results: The results show that there are significant variations in the performance of the movement among groups of men actively engaged in squats under professional guidance and...
Collagen structures from cell culture to intact tendon
Hadraba, Daniel ; Jelen, Karel (advisor) ; Amler, Evžen (referee) ; Plášek, Jaromír (referee)
CHARLES UNIVERSITY and HASSELT UNIVERSITY / tUL Doctoral dissertation Collagen structures from cell culture to intact tendon ABSTRACT Author: Daniel Hadraba Promoters: Assoc. Prof. Karel Jelen | Charles University Prof. Marcel Ameloot | Hasselt University Co-promoters: Dr. Frantisek Lopot | Charles University Prof. Virginie Bito | Hasselt University Annotation Author: Ing. Mgr. Daniel Hadraba Doctoral thesis title: Collagen structures from cell culture to intact tendon Year: 2010 - 2017 Doctoral program: Doctor of Biomechanics at Charles University Doctor of Biomedical Science at Hasselt University / transnational University Limburg Departments: Dept. Anatomy and Biomechanics | Faculty of Physical Education and Sport | Charles University Dept. Biophysics | Hasselt University Promoters: Assoc. Prof. Karel Jelen | Dept. Anatomy and Biomechanics | Faculty of Physical Education and Sport | Charles University Prof. Marcel Ameloot | Hasselt University / transnational University Limburg Co-promoters: Dr. Frantisek Lopot | Dept. Anatomy and Biomechanics | Faculty of Physical Education and Sport | Charles University Prof. Virginie Bito | Hasselt University / transnational University Limburg Bibliography details: Pages 102 Figures 30 Tables 2 Equations 17 Keywords: tendon, collagen, crimps, orientation, aging,...
Changes in the mechanical parameters of women's hair during pregnancy
Skřontová, Marie ; Jelen, Karel (advisor) ; Tlapáková, Eva (referee) ; Berchová, Kateřina (referee)
Title: Changes in the mechanical parameters of women's hair during pregnancy Matters: We can look from different angles on the hair - as on a nanocomposite fiber and as on biomaterial changing with the origin and age. The hair doesn't differ only by lenght, stucture and color but also by diameter and shape. It reflects the overall health of the individual and all the processes in the organism of the individual and thus also the pregnancy. During pregnancy, hormonal changes take place which have an effect on the hair. Many women experience faster hair growth, extension and increased volume of the hair during pregnancy. This status is only temporary and lasts only to the childbirth. Aim: The aim of this work was to show the influence of pregnancy on mechanical parameters of hair and what direction this influence takes. Next, using questionnaires, to better solve the effect of particular pregnancy parameters on the hair, i.e. pregnancy order, sex of the child. Then, evaluate the whole problem using statistical tests and so make better sense of it. Methods: We'd selected a group of 64 pregnant women; hair samples were cut from them in the nape area each month throughout pregnancy. Each measurement started with evaluation of hair diameter with the use of optical microscope. Next, the hair had been...
The CVS method as a diagnostic of the cardiovascular system
Procházka, Marek ; Jelen, Karel (advisor) ; Tlapáková, Eva (referee)
Title: The CVS method as a diagnostic of the cardiovascular system Objective: The aim of this thesis is to introduce the CVS (cardiovascular system) method as a potential diagnostic method to detect the overloading of the heart muscle, and thereby increased susceptibility to subsequent myocardial infarction and hypertension. Method: This thesis presents a data analysis on different groups of people, which were provided to us during the development of the CVS method. These were several groups of healthy individuals (athletes) and three groups of patients suffering from problems with the cardiovascular system (colaps conditions, obesity and hypertension). The groups were measured for their values of the heart rate and blood pressure at rest and during exercise on a bicycle ergometer. Subsequently the energy required to pump blood to the heart muscle and climbing speed pulse pressure depending on the heart rate was evaluated. Results: The CVS method shows differences in the energy consumption of the heart muscle in various groups of people. The results showed that at the same level of exercise the load of the heart muscle is higher by patients than by athletes. Considering the samples that we had available, the CVS method proved its diagnostic value when evaluating the overall effectiveness of the...
Pelvis position in 3D space and its influence of stages of pregnancy
Vosátková, Marie ; Jelen, Karel (advisor) ; Hendl, Jan (referee)
Title: Pelvis position in 3D space and its infuence of stages of pregnancy Summary: The aim of this master thesis is to evaluate changes of the pelvis position of women during pregnancy and if these changes influence the LBP during gravidity. The research is based on the summary of theoretical findings about the issue of changes during pregnancy which could be responsible for the LBP. The main topics of this part of thesis are anatomy and kinesiology of pelvis, functional vertebral disorders, LBP in gravidity, physiological and biomechanical changes during pregnancy, definition of 3D space with connection to human body and introduction of the 3D kinematic analysis. 10 (9) pregnant women in the age of 26-35 years was evaluated in 3rd , 5th and 8th month of gravidity. The pelvis position in 3D space was objectified with the Qualisys technology and the LBP and the PGP with subjective evaluation of the VAS. LBP was found in 7 of 10 and PGP in 3 of 10 evaluated pregnant women. Our findings show the tendency to the change of the pelvis position in the sagittal plane in the direction of the forward tilt. In our group of evaluated woman was found the connection between the absolute change of the pelvis position in the sagittal plane and the LBP and the PGP during pregnancy, but to define clear and...
Lower limb proportions and energetic cost of locomotion in Upper Pleistocene humans
Hora, Martin ; Sládek, Vladimír (advisor) ; Jelen, Karel (referee) ; Jandačka, Daniel (referee)
Previous studies proposed that Neandertals had one third higher energetic cost of locomotion than anatomically modern humans. Greater cost of locomotion could disadvantage Neandertals in competition with anatomically modern humans and could be a factor in their extinction. Greater cost of Neandertal locomotion was ascribed to their shorter lower limb and greater body mass. However, Neandertals differed also in other morphological parameters that were not considered in estimation of their locomotor cost. In this dissertation we model locomotor cost of Neandertals and anatomically modern humans using previously described relation between muscle force production and energetic cost of movement. We estimate the key locomotor parameters using a model developed by us from osteometric data from literature (n =50) and from our measurement (n = 21), and from kinematic data of 26 individuals. Further, we analyze the effect of relative lower limb length (in relation to body mass) and crural index on energetic cost of locomotion. Our results suggest that walking of Neandertal males was 9-14% energetically more demanding than walking of anatomically modern males. Nevertheless, the walking cost of Neandertal females was similar to that of anatomically modern females. Inclusion of lower limb proportions into the...

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