The purpose of the study was to determine the proportion of engagements of individual breathing sectors during 1-min physically active breathing at rest in 163 healthy, physically active participants (students of Physical Education and Sport). The research analyzed breathing movements through the muscle dynamometer MD03 (Hitron, Plzeň, Czech Republic). The proportion of engagements of the individual breathing sector in the group analyzed was determined based on measurement results. The lower breathing sector was engaged at 29.2%, the middle breathing sector at 31.0%, and the upper breathing sector at 39.8%. The largest observed difference between the involvement of individual breath sectors was 10.6% between the lower and upper breathing sectors. The muscle dynamometer MD03 may be instrumental for practising both localized breathing and full breath.
This case study describes the experimental determination of displacements and stresses on a composite model of a pelvis that was modified to represent a healthy intact pelvic ring. The modified model was stressed statically up to 1750 N to simulate standing on one leg and also cyclically to model walking. For two different model settings in the loading machine the values of displacements and stresses at the pelvic ring were determined. The two different settings correspond to two different loading vectors applied on the pelvic ring, boundary conditions and degrees of freedom. The experimentally determined values of displacements in both settings are very similar and in accordance with the knowledge on the behaviour of a real human pelvis. The modified model is thus suitable for testing of newly developed implants for pelvis treatment and experimental determination of displacements and stresses in pelvic ring which are caused by application of implants.
- MeSH
- biomechanika MeSH
- lidé MeSH
- pánev * MeSH
- pánevní kosti * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Surgical treatment of spine metastases follows only local anatomical and biomechanical objectives. Few cases of actual solitary metastases are rather exceptional, while removal of these metastases and the primary tumor may help to eradicate the process. The aim of our subsequent numerical simulations was to find out the temperature distribution and the volume lesion in a spinal tumor. For this purpose, the parametric three-dimensional numerical model was developed. It was shown that by finite element modeling approach not only the temperature distribution but even the resulted cavity may be estimated. The numerical approach was shown as a strong tool in surgery planning.
The clinical practice shows that the loosening of acetabular cups is more frequent than stem loosening. With standard cups, the incidence of dislocation failure is highest in the first year after arthroplasty implantation. The aim of the study was to quantitatively evaluate the implant-bone stability of a cementless acetabular cup prosthesis by using a device based on resonance frequency analysis. The evaluation of this device was done by finite element analysis and in vitro experiments. It was shown that not all the resonance frequencies can be measured by our device. The resonance frequencies vary within the range of 500-3000 Hz. The proposed power spectrum measurement gives the information about the absolute stiffness of the press-fit implant.
- MeSH
- acetabulum fyziologie chirurgie MeSH
- analýza metodou konečných prvků MeSH
- analýza selhání vybavení metody MeSH
- biologické modely * MeSH
- kyčelní protézy MeSH
- lidé středního věku MeSH
- lidé MeSH
- mechanický stres MeSH
- modul pružnosti fyziologie MeSH
- náhrada kyčelního kloubu přístrojové vybavení metody MeSH
- oscilometrie metody MeSH
- počítačová simulace MeSH
- protetické vybavení metody MeSH
- reprodukovatelnost výsledků MeSH
- senzitivita a specificita MeSH
- vibrace MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Researchers have been studying aerosol transport in human lungs for some decades. The overall lung deposition can be predicted with sufficient precision nowadays. However, the prediction of local deposition remains an unsolved problem. Numerical modeling of aerosol transport can provide detailed data with such precision and spatial resolution which were unavailable in the past. Yet, the necessary validation of numerical results represents a difficult task, as the experimental data in a sufficient spatial resolution are hardly available. This article introduces a method based on positron emission tomography, which allows acquisition of detailed experimental data on local aerosol deposition in a realistic model of human lungs. The method utilizes the Condensation Monodisperse Aerosol Generator modified for a safe production of radioactive aerosol particles and a special measuring rig. The scanning of the model is performed on a positron emission tomography-computed tomography scanner. The evaluation of aerosol deposition is based on a volume radioactivity analysis in a specialized, yet publicly available software. The reliability of the method was tested and its first results are discussed in the article. The measurements performed using the presented method can serve for validation of numerical simulations, since the presented lung model digital geometry is available.
- MeSH
- aerosoly aplikace a dávkování farmakokinetika MeSH
- biologické modely * MeSH
- bronchy metabolismus MeSH
- lidé MeSH
- pozitronová emisní tomografie metody MeSH
- systémy cílené aplikace léků MeSH
- trachea metabolismus MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The aim of this study is to consider the relevance of in situ measurements of bovine serum film thickness in the optical test device that could be related to the function of the artificial hip joint. It is mainly focussed on the effect of the hydrophobicity or hydrophilicity of the transparent surface and the effect of its geometry. Film thickness measurements were performed using ball-on-disc and lens-on-disc configurations of optical test device as a function of time. Chromatic interferograms were recorded with a high-speed complementary metal-oxide semiconductor digital camera and evaluated with thin film colorimetric interferometry. It was clarified that a chromium layer covering the glass disc has a hydrophobic behaviour which supports the adsorption of proteins contained in the bovine serum solution, thereby a thicker lubricating film is formed. On the contrary, the protein film formation was not observed when the disc was covered with a silica layer having a hydrophilic behaviour. In this case, a very thin lubricating film was formed only due to the hydrodynamic effect. Metal and ceramic balls have no substantial effect on lubricant film formation although their contact surfaces have relatively different wettability. It was confirmed that conformity of contacting surfaces and kinematic conditions has fundamental effect on bovine serum film formation. In the ball-on-disc configuration, the lubricant film is formed predominantly due to protein aggregations, which pass through the contact zone and increase the film thickness. In the more conformal ball-on-lens configuration, the lubricant film is formed predominantly due to hydrodynamic effect, thereby the film thickness is kept constant during measurement.
- MeSH
- adsorpce MeSH
- biomechanika MeSH
- hydrofobní a hydrofilní interakce MeSH
- interferometrie metody MeSH
- kyčelní protézy * MeSH
- lubrikanty chemie MeSH
- sérum chemie MeSH
- skot MeSH
- smáčivost MeSH
- testování materiálů metody MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Dorsal pain caused by spine dysfunctions belongs to most frequent chronic illnesses. The muscles of the deep stabilising spine system work as a single functional unit where a dysfunction of only one muscle causes dysfunction of the whole system. Non-invasive, objective and statistically measurable evaluation of the condition of deep stabilising spine system has been made possible by the construction of muscular dynamometer. The aim of our work has been the assessment of deep stabilising spine system by diaphragm test and muscular dynamometer measurements. Based on an initial examination, a 6-week intervention programme was established including instructions on physiological body posture and correct basic body stabilisation for the given exercises and muscle strengthening. Consecutive measurements are then compared with the initial ones. It was presumed that a smaller number of the tested subjects would be able to correctly activate the deep stabilising spine system muscles before the intervention programme when compared to those after the intervention programme. A positive change of 87% has been found. It is clear that if a person actively approaches the programme, then positive adaptation changes on the deep stabilising spine system are seen only after 6 weeks. With the muscular dynamometer, activation of deep stabilising spine system can be objectively measured. Changes between the initial condition of a subject and the difference after some exercise or rehabilitation are especially noticeable. Also, the effect of given therapy or correct performance of the exercise can be followed and observed.
- MeSH
- bránice fyziologie MeSH
- dítě MeSH
- lidé MeSH
- lumbalgie patofyziologie rehabilitace MeSH
- mladiství MeSH
- páteř patofyziologie MeSH
- postura těla fyziologie MeSH
- svalová síla - dynamometr * MeSH
- terapie cvičením přístrojové vybavení metody MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Numerous models of human lungs with various levels of idealization have been reported in the literature; consequently, results acquired using these models are difficult to compare to in vivo measurements. We have developed a set of model components based on realistic geometries, which permits the analysis of the effects of subsequent model simplification. A realistic digital upper airway geometry except for the lack of an oral cavity has been created which proved suitable both for computational fluid dynamics (CFD) simulations and for the fabrication of physical models. Subsequently, an oral cavity was added to the tracheobronchial geometry. The airway geometry including the oral cavity was adjusted to enable fabrication of a semi-realistic model. Five physical models were created based on these three digital geometries. Two optically transparent models, one with and one without the oral cavity, were constructed for flow velocity measurements, two realistic segmented models, one with and one without the oral cavity, were constructed for particle deposition measurements, and a semi-realistic model with glass cylindrical airways was developed for optical measurements of flow velocity and in situ particle size measurements. One-dimensional phase doppler anemometry measurements were made and compared to the CFD calculations for this model and good agreement was obtained.
The aim of this study was to compare two tests both frequently used for determination of the state of the lumbar spine muscle system during static and dynamic loads. The sit-up test is a commonly used terrain test, while the diaphragm test is a more exact laboratory procedure. For both tests, measurements conducted by the muscular dynamometer SD02 were used to assure congruency in evaluation. The tests are based on the general information that the muscles of the deep stabilizing spine system (DSSS) are interconnected and form one functional unit, and that dysfunction of just one of these muscles may cause total dysfunction of the whole muscle system. It is therefore expected that the participation and force generated by the largest muscles of the area, musculus rectus abdominis and musculus transversus abdominis, will be comparable also during the testing procedures. Forty-five healthy women joined in the research, with the average age of 21.6 years. The results obtained were statistically evaluated using Statistica 6. The results showed the clear incapability of the sit-up test to indicate correctly the imbalances of the muscles of the DSSS, also implying that the tested subjects suffer to a high degree from dysfunctions of the DSSS.
- MeSH
- analýza selhání vybavení MeSH
- břišní svaly fyziologie MeSH
- design vybavení MeSH
- lidé MeSH
- mladý dospělý MeSH
- reprodukovatelnost výsledků MeSH
- senzitivita a specificita MeSH
- svalová kontrakce fyziologie MeSH
- svalová síla - dynamometr MeSH
- Check Tag
- lidé MeSH
- mladý dospělý MeSH
- ženské pohlaví MeSH
- Publikační typ
- hodnotící studie MeSH
- srovnávací studie MeSH
