Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "Horny, L." wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Fixation of distal fibular fractures: A biomechanical study of plate fixation techniques
Autorzy:
Marvan, J.
Horak, Z.
Vilimek, M.
Horny, L.
Kachlik, D.
Baca, W.
Powiązania:
https://bibliotekanauki.pl/articles/306556.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
analiza FEM
osteosynteza
złamanie kości
fibular fracture
finite element analysis
osteosynthesis
fracture fixation
fibula
Opis:
Ankle fractures are complex injuries with variable prognoses that depend upon many factors. The aim of the treatment is to restore the ankle joint biomechanical stability with maximum range of motion. Most ankle fractures are fibular fractures, which have a typical oblique fracture line in the distal fibula located in the area of the tibiofibular syndesmosis. The aim of this study was to simulate numerically several fixation techniques of the distal fibular fractures, evaluate their stability, determine their impact on surrounding tissue load, and correlate the results to clinical treatment experience. The following three models of fibular fracture fixation were used: (a) plate fixation with three screws attached above/below and lag screws, (b) plate fixation with two screws attached above/below and lag screws, and (c) three lag screws only. All three fracture fixation models were analyzed according to their use in both healthy physiological bone and osteoporotic bone tissue. Based on the results of Finite Element Analysis for these simulations, we found that the most appropriate fixation method for Weber-B1 fibular fractures was an unlocked plate fixation using six screws and lag screws, both in patients with physiological and osteoporotic bone tissue. Conversely, the least appropriate fixation method was an unlocked plate fixation with four screws and lag screws. Although this fixation method reduces the stress on patients during surgery, it greatly increased loading on the bone and, thus, the risk of fixation failure. The final fixation model with three lag screws only was found to be appropriate only for very limited indications.
Źródło:
Acta of Bioengineering and Biomechanics; 2017, 19, 1; 33-39
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The evaluation of adhesion between electrospun collagen layers and different titanium substrates
Autorzy:
Sedlacek, R.
Suchy, T.
Supova, M.
Sucharda, Z.
Kuzma, J.
Horny, L.
Powiązania:
https://bibliotekanauki.pl/articles/285558.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
antibiotic treatment
collagen layers
titanium alloys
Źródło:
Engineering of Biomaterials; 2016, 19, 138; 16
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The sustainable release of vancomycin from micro- and nanostructured collagen layers
Autorzy:
Suchy, T.
Šupova, M.
Klapkova, E.
Adamkova, V.
Pokorny, M.
Denk, F.
Horny, L.
Powiązania:
https://bibliotekanauki.pl/articles/286191.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
vancomycin
collagen layers
endoprostheses
Źródło:
Engineering of Biomaterials; 2016, 19, 138; 40
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparison between the exponential and limiting fiber extensibility pseudo-elastic model for the Mullins effect in arterial tissue
Autorzy:
Gultova, E.
Horny, L.
Chlup, H.
Powiązania:
https://bibliotekanauki.pl/articles/281872.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
aorta
limiting fiber extensibility
Mullins effect
Opis:
This study compares the capability of two different mathematical forms of the so-called softening variable to describe strain-induced stress softening observed within cyclic uniaxial tension of the human thoracic aorta. Specifically, the softening variable, which serves as the stress reduction factor, was considered to be tangent hyperbolic-based and error function-based. The mechanical response of the aorta was assumed to be pseudo-hyperelastic, incompressible and anisotropic. The strain energy density function was employed in a classical exponential form and in a not well-known limiting fiber extensibility model. This study revealed that both the limiting fiber extensibility and exponential models of the strain energy describe mechanical the response of the material with similar results. It was found that it is not a matter which kind of the softening variable is employed. It was concluded that such an approach can fit the Mullins effect in the human aorta, however the question of the best fitting model still remains.
Praca zawiera analizę porównawczą poprawności dwóch różnych matematycznych sformułowań tzw. zmiennej osłabienia przy opisie zjawiska osłabienia naprężeń indukowanych odkształceniem obserwowanym podczas cyklicznego jednoosiowego rozciągania aorty piersiowej. W szczególności, zmienną osłabienia jako czynnika redukującego poziom naprężeń opisano funkcją typu tangens hiperboliczny oraz funkcją błędu. Założono, że mechaniczne właściwości aorty odpowiadają modelowi pseudohipersprężystemu, nieściśliwemu i anizotropowemu. Funkcję gęstości energii odkształcenia przyjęto w klasycznej formie wykładniczej i mało rozpoznanej postaci, która ogranicza zakres rozszerzalności włókien. Badania wykazały, że obydwa podejścia opisują właściwości mechaniczne tkanki z podobnym skutkiem. Pokazano, że rodzaj przyjętej zmiennej osłabienia nie ma wpływu na rezultaty badań. W konkluzji podkreślono, że obydwa modele nadają się do analizy efektu Mullinsa w aorcie, jakkolwiek nadal otwartą kwestią pozostaje problem znalezienia najlepiej dopasowanego modelu do opisu tego zjawiska.
Źródło:
Journal of Theoretical and Applied Mechanics; 2011, 49, 4; 1203-1216
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Limiting fiber extensibility model for arterial wall
Autorzy:
Horny, L.
Zitny, R.
Chlup, H.
Konvickova, S.
Powiązania:
https://bibliotekanauki.pl/articles/286066.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
arterial walls
fibers
biomaterials
Opis:
Arterial walls exhibit anisotropic, nonlinear and inelastic response to external loads. Moreover arterial wall is non–homogenous material with complicated internal structure. These facts make the question about the best material model for arterial wall still unanswered. Nowadays approach to building constitutive models is characterized by incorporating structural information when considering e.g. layers, fibers, fiber orientation or waviness. The most frequent method how to incorporate structural information is to regard arterial wall as a fiber reinforced composite. Considerations about preferred directions are subsequently implemented into the framework of continuum mechanics. Constitutive models are usually based on the theory of hyperelastic materials. Thus mechanical response of an arterial wall is supposed to be governed by a strain energy (or free energy) density function like in (1). The theory of hyperelastic materials is widely applied and studied in details in polymer science. Due to some phenomenological and structural similarities between rubber–like materials and biological tissues, methods of polymer physics are frequently applied in biomechanics, see Holzapfel [1]. Gent [2] suggested the new isotropic model for strain energy density function which was based on an assumption of limiting chain extensibility in polymer materials. The Gent model expresses strain energy y as a function of first invariant I1 of the right Cauchy-Green strain tensor as follows [formula]. In equation (1) μ denotes stress–like parameter, so–called infinitesimal shear modulus. Jm denotes limiting value of I 1 -3. The domain of logarithm requires [formula]. Thus, Jm can be interpreted as limiting value for macromolecular chains stretch. Horgan and Saccomandi in [3] suggested its anisotropic extension. They recently published modification based on usual concept of anisotropy related to fiber reinforcement, see paper [4]. Horgan and Saccomandi use rational approximations to relate the strain energy expression to Cauchy stress representation formula. We adopted this term with small modification as follows [formula] In (2) μ denote shear modulus. J m is the material parameter related to limiting extensibility of fibers. The similar definitional inequality like in (1) must be hold for logarithm in (2). Thus I 4 must satisfy [formula] denotes so called fourth pseudo–invariant of the right Cauchy-Green strain tensor which arises from the existence of preferred direction in continuum. It is worth to note that total number of invariants of the strain tensor is five in the case of transversely isotropic material and nine in the case of orthotropy. Details can be found in e.g. Holzapfel [5]. Model (2) presumes two preferred directions in continuum which are mechanically equivalent. Due to cylindrical shape of an artery we can imagine it as helices with same helix angel but with antisymmetric rientation. This is illustrated in the FIG. 1 I 4 can be expressed in the form given in (3) [formula] Stretched configuration of the tube is characterized by λ t , what denotes circumferential stretch and λ z what denotes axial stretch, respectively. Model (2) contains three material parameters. Above described μ, J m and β. The third material parameter β has the meaning of angle between fiber direction and circumferential axis. There are two families of fibers with angle ±β, however, I 4 is symmetric with respect to ±β. In order to verify capability of (2) to govern multi–axial mechanical response of an artery regression analysis based on previously published experimental data was performed. Details of experimental method and specimen can be found in Horny et al. [6]. Briefly we resume basic facts. Male 54–year–old sample of thoracic aorta underwent inflation test under constant axial stretch. The tubular sample was 6 times pressurized in the range 0kPa–18kPa–0kPa under axial pre–stretch λ z =1.3 and 3 times in the pressure range 0kPa–20kPa–0kPa under λ z =1.42, respectively. The opening angle was measured in order to account residual strains. Radial displacements were photographed and evaluated by image analysis. Regression analysis based on least square method gave the estimations for material parameters μ, Jm and β. The vessel was modeled as thick–walled tube with residual strains. The material was supposed to be hyperelastic and incompressible. No shear strains were considered. Fitting of material model was based on comparison of model predicted and measured values of internal pressure. Results are illustrated in FIG. 2. We can conclude that proposed material model fits experimental data successfully. Thus strain energy given in (2) is suitable to govern arterial response during its inflation and extension. Estimated values of parameters for material model (2) are as follows: μ =26kPa; J m =1.044; β=37.2°
Źródło:
Engineering of Biomaterials; 2008, 11, no. 81-84; 112-113
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

    Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies