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Wyświetlanie 1-8 z 8
Tytuł:
Is bearing resistance negligible during wheelchair locomotion? Design and validation of a testing device
Autorzy:
Bascou, J.
Sauret, Ch.
Lavaste, F.
Pillet, H.
Powiązania:
https://bibliotekanauki.pl/articles/307222.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wózek inwalidzki
nośność
prędkość obrotowa
wheelchair
bearing resistance
rotation velocity
Opis:
Purpose: Among the different resistances occurring during wheelchair locomotion and that limit the user autonomy, bearing resistance is generally neglected, based on a few studies carried out in static conditions and by manufacturer’s assertion. Therefore, no special attention is generally paid to the mounting and the maintenance of manual wheelchair bearings. However, the effect of inadequate mounting or maintenance on wheelchair bearing resistance has still to be clarified. This study aimed at filling this gap by developing and validating a specific device allowing the measurement of wheelchair bearing friction, characterized by low speed velocities, with an accuracy lower than 0.003 Nm. Methods: The bearing resistance measured by the device was compared to free deceleration measurement, intra and inter operator reproducibility were assessed. A factorial experiment allowed the effects of various functioning parameters (axial and radial loads, velocity) to be classified. Results: The device allowed significant differences in the bearing resistance of static and rotating conditions to be measured, even if a relatively high proportionality was found between both conditions. The factorial experiment allowed the expected impact of the radial load on bearing resistance as well as the predominant effect of the axial load to be demonstrated. Conclusions: As a consequence, it appeared that the control of the axial load is compulsory for measurement purposes or during wheel mounting, to avoid significant increase of global resistance during wheelchair locomotion. The findings of this study could help enhancing the models which assess manual wheelchair mechanical power from its settings and use conditions.
Źródło:
Acta of Bioengineering and Biomechanics; 2017, 19, 3; 165-176
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of electrophysical and structural properties of human cancellous bone and synthetic bone substitute material using impedance spectroscopy and X-ray powder diffraction
Autorzy:
Haba, Y.
Köckerling, M.
Shick, Ch.
Mittelmeier, W.
Bader, R.
Powiązania:
https://bibliotekanauki.pl/articles/306920.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
kość syntetyczna
spektroskopia impedancyjna
dyfrakcja promieniowania rentgenowskiego
human cancellous bone
synthetic bone
impedance spectroscopy
X-ray powder diffraction
Opis:
Electrophysical stimulation is used to support fracture healing and bone regeneration. For design optimization of electrostimulative implants, in combination with applied human donor bone or synthetic bone scaffolds, the knowledge of electrophysical properties is fundamental. Hence further investigations of the structural properties of native and synthetic bone is of high interest to improve biofunctionality of bone scaffolds and subsequent healing of the bone defect. The investigation of these properties was taken as an objective of this study. Therefore, surgically extracted fresh cylindrical and consecutively ashed cancellous bone samples from human osteoarthritic femoral heads were characterized and compared to synthetic bone substitute material. Thereby, impedance spectroscopy is used to determine the electrophysical properties and X-ray powder diffraction (XRD) for analysis of structural information of the bone samples. Conductivity and permittivity of fresh and ashed cancellous bone amounted to 1.710–2 S/m and 7.5106 and 210–5 S/m and 7.2103 , respectively. Electrical conductivity and dielectric permittivity of bone scaffold resulted in 1.710–7 S/m and 49. Analysis of the structural properties showed that the synthetic bone scaffolds made of Brushite exhibited some reflections which correspond to the native bone samples. The information in present study of the bone material (synthetic and autologous) could be used for later patient individual application of electrostimulative implants.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 1; 11-19
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The description of the human knee as four-bar linkage
Autorzy:
Dathe, H.
Gezzi, R.
Fiedler, Ch.
Kubein-Meesenburg, D.
Nägerl, H.
Powiązania:
https://bibliotekanauki.pl/articles/307351.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
staw kolanowy
anatomia
kinematyka kolana
human knee
anatomy
knee kinematics
four-bar linkage
analytical description
Opis:
Purpose: We investigate the dependence of the kinematics of the human knee on its anatomy. The idea of describing the kinematics of the knee in the sagittal plane using four-bar linkage is almost as old as kinematics as an independent discipline. We start with a comparison of known four-bar linkage constructions. We then focus on the model by H. Nägerl which is applicable under form closure. Methods: We use geometry and analysis as the mathematical methods. The relevant geometrical parameters of the knee will be determined on the basis of the dimensions of the four-bar linkage. This leads to a system of nonlinear equations. Results: The four-bar linkage will be calculated from the limits of the constructively accessible parameters by means of a quadratic approximation. Conclusions: By adapting these requirements to the dimensions of the human knee, it will be possible to obtain valuable indications for the design of an endoprosthesis which imitates the kinematics of the natural knee.
Źródło:
Acta of Bioengineering and Biomechanics; 2016, 18, 4; 107-115
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Elastic modulus for long-term evaluation of the tensile properties of polypropylene meshes in an in vivo rat model
Autorzy:
Przydacz, M.
Mahfouz, W.
Loutochin, O.
Ghezzi, Ch. E.
Carmel, M.
Corcos, J.
Powiązania:
https://bibliotekanauki.pl/articles/306894.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wytrzymałość
stała sprężystości
I-STOP
TVT-O
tensile properties
elastic modulus
mid-urethral slings
Opis:
Mid-urethral slings have become the gold standard treatment of stress urinary incontinence in women. Their tensile properties should be evaluated to measure how they wear off with time. Our objective was long-term assessment of the tensile properties of 2 synthetic tapes (TVT-O and I-STOP) after in vivo implantation in rats in terms of elastic modulus. Methods: Strips from both meshes were implanted in the abdominal wall of 30 rats, which were sacrificed at 5 time intervals. Their fibers were untangled to single components. Ultimate tensile strength (UTS), strain at UTS and the elastic modulus of each fiber type were measured. Results: I-STOP maintained UTS and strain over time, while TVT-O UTS and strain were significantly reduced. However, the elastic modulus of both tapes remained constant. Conclusions: Both meshes maintained their stiffness and elasticity with time. Elastic modulus could be an appropriate factor to predict long-term implantation outcomes. The clinical significance of such findings remains to be demonstrated by long-term analysis.
Źródło:
Acta of Bioengineering and Biomechanics; 2017, 19, 4; 153-160
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Footwear and Equipment on Stride Length and Range of Motion of Ankle, Knee and Hip Joint
Autorzy:
Schulze, Ch.
Lindner, T.
Woitge, S.
Schulz, K.
Finze, S.
Mittelmeier, W.
Bader, R.
Powiązania:
https://bibliotekanauki.pl/articles/306456.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
analiza chodu
sprzęt wojskowy
biomechanika
gait analysis
goniometry
military equipment
oversue syndromes
Opis:
Purpose: Footwear and equipment worn by military personnel is of importance for them to be able to meet the physical demands specific to their profession daily activities. Aim of the present study was to investigate by means of gait analysis how army-provided footwear and equipment influence the range of motion of hip, knee and ankle joints as well as stride length.Methods: Thirty-two soldiers were subjected to gait analysis on a treadmill by way of video recordings and goniometric measurements. Results: The stride length increased when military shoes are worn. We found no influence on stride length in connection to increased loading. The weight of the shoes represents the decisive factor. Neither shoes nor equipment changed the range of motion of the knee joint.Weight of equipment affected range of motion of the hip joint. The range of motion of the upper and lower ankle joints was mainly influenced by the properties of the shoes. Conclusions: Military footwear and weight of equipment influence stride length and range of motion of joints of the lower extremities in a specific way. Shape of material is the decisive factor.
Źródło:
Acta of Bioengineering and Biomechanics; 2014, 16, 4; 45-51
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biomechanical study of the influence of the weight of equipment on selected trunk muscles
Autorzy:
Schulze, Ch.
Lindner, T.
Woitge, S.
Glass, A.
Fimze, S.
Mittelmeier, W.
Bader, R.
Powiązania:
https://bibliotekanauki.pl/articles/306939.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
activity
EMG
equipment
posture
aktywność
postawa
Opis:
Overexertion and pain of the musculoskeletal system may occur partly owing to load application by the equipment. Both the weight of equipment and the duration of loading are relevant. The aim of the present study was to examine the extent of loading and resultant strain in the trunk muscles. Therefore, the trunk posture of soldiers and muscular activity in reaction to different equipment components (helmet, load-carrying equipment, gun and backpack) were evaluated. Electromyography was performed and a visual assessment of body axis was conducted based on standardised planar images. Data indicate that the activity of the trunk muscles examined (latissimus dorsi, trapezius and pectoralis major) is dependent on the weight and distribution of the equipment components. Activity in the trapezius muscle, for instance, was doubled during specific load application. Moreover, the method of carrying the rifle had a significant influence on the activity of the trapezius muscle (one-sided decrease of activity by 50%). Subjects were able to stabilise the body axis in the coronal plane through increased muscle activity, however, in the sagittal plane a compensatory ventral inclination of the body was observed. Uneven load distribution can lead to an irregular strain on the musculoskeletal system.
Źródło:
Acta of Bioengineering and Biomechanics; 2013, 15, 3; 45-51
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of multi-task on symptomatic patient affected by chronical vestibular disorders
Autorzy:
Regrain, E.
Regnault, P.
Kirtley, Ch.
Shamshirband, S.
Chays, A.
Boyer, F.-C.
Taiar, R.
Powiązania:
https://bibliotekanauki.pl/articles/307436.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rehabilitacja
posturograf
zdolność
postawa człowieka
rehabilitation
posturography
ability
cognitive skills
vestibular disorders
anxiety posture balance
Opis:
Purpose: After a vestibular deficit some patients may be affected by chronical postural instability. The aim of this study was to identify the emotional and cognitive factors of these symptomatic patients. In particular, the double cognitive task and the anxiety disorder were identified by our patients. Through a retrospective study, 14 patients (65.4 ±18 years) participated in the experiment. Method: The experimentation consists in the study of the standing position of our patients through the aggregate of the trajectories of the center of pressure (COP) using a force plate device. With the aim of isolating the emotional and cognitive influence, this experimentation was defined in two conditions. In the first one, the patients were asked to maintain their balance without additional tasks. In the second one, the patients were submitted to an additional cognitive arithmetic task. The stabilogram surface, length (the forward and backward displacement distance during deviations in COP), lateral and the antero-posterior deviations were assessed. Results: Our results showed an increase of postural instability of patients affected by chronical vestibular disorders when submitted to the double task. The patients submitted to the cognitive task present a larger surface of activity in comparison with the free-task one (Wilcoxon test p-value equals p = 0.0453). In addition, their displacements inside this area are more important (p = 0.0338). The COP of all our patients deviated forward in the presence of the double task. Conclusion: The increase in instability during the double cognitive task could be explained by an additional stress caused by the desire to make a success of the cognitive task.
Źródło:
Acta of Bioengineering and Biomechanics; 2016, 18, 3; 123-129
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The morphology of the articular surfaces of biological knee joints provides essential guidance for the construction of functional knee endoprostheses
Autorzy:
Nagerl, H.
Dathe, H.
Fiedler, Ch.
Gowers, L.
Kirsch, S.
Kubein-Meesenburg, D.
Dumont, C.
Wachowski, M. M.
Powiązania:
https://bibliotekanauki.pl/articles/307060.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
kolano
kinematyka
biomechanika
endoproteza
knee arthroplasty
kinematics
biomechanics
knee
endoprosthesis
pig
Opis:
Purpose: In comparative examinations of kinematics of the knees of humans and pigs in flexional/extensional motion under compressive loads, the significant differential geometric essentials of articular guidance are elaborated to criticise the shaping of the articular surfaces of conventional knee-endoprostheses and to suggest constructional outlines that allow the endoprosthesis to adopt natural knee kinematics. Implantation is discussed with regard to the remaining ligamentous apparatus. Methods: Twelve fresh pig knee joints and 19 preserved human knee joints were moved into several flexional/extensional positions. In each joint, the tibia and femur were repeatably caught by metal plates. After removing all ligaments, the tibia and femur were again caught in these positions, and their points of contact were marked on both articular surfaces. Along the marker points, a thin lead wire was glued onto each surface. The positions and shapes of the four contact lines were mapped by teleradiography. Results: All contact lines were found to be plane curves. The medial and lateral planes were parallel, thus defining the joint’s sagittal plane. In the human knee, as compared to the lateral, the medial femoral contact line was always shifted anteriorly by several millimetres. The tibial contact curve was laterally convex and medially concave. In the pig knees, the lateral and medial contact lines were asymmetrically placed. Both tibial curves were convex. Conclusions: Both knees represent cam mechanisms (with one degree of freedom) that produce rolling of the articular surfaces during the stance phase. Implantation requires preservation of the anterior cruciate ligament, and ligamentous balancing is disadvantageous.
Źródło:
Acta of Bioengineering and Biomechanics; 2015, 17, 2; 45-53
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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