Wyniki wyszukiwania - BazTech

1

Estimation of random bio-hydrodynamic lubrication parameters for joints with phospholipid bilayers

Wierzcholski Krzysztof, Miszczak Andrzej

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2021

|

Vol. 69, nr 1

art. no. e135834

EN

This paper presents a new form of a mathematical estimation of stochastic bio-hydrodynamic lubrication parameters for real human joint surfaces with phospholipid bilayers. In this work, the authors present the analytical and stochastic considerations, which are based on the measurements of human joint surfaces. The gap is restricted between two cooperating biological surfaces. After numerous experimental measurements, it directly follows that the random symmetrical as well as unsymmetrical increments and decrements of the gap height in human joints influence the hydrodynamic pressure, load-carrying capacity, friction forces, and wear of the cooperating cartilage surfaces in human joints. The main focus of the paper was to demonstrate the influence of variations in the expected values and standard deviation of human joint gap height on the hydrodynamic lubrication parameters occurring in the human joint. It is very important to notice that the new form of apparent dynamic viscosity of synovial fluid formulated by the authors depends on ultra-thin gap height variations. Moreover, evident connection was observed between the apparent dynamic viscosity and the properties of cartilage surface coated by phospholipid cells. The above observations indicate an indirect impact of stochastic changes in the height of the gap and the indirect impact of random changes in the properties of the joint surface coated with the phospholipid layers, on the value of hydrodynamic pressure, load carrying capacity and friction forces. In this paper the authors present a synthetic, comprehensive estimation of stochastic bio-hydrodynamic lubrication parameters for the cooperating, rotational cartilage bio-surfaces with phospholipid bilayers occurring in human joints. The new results presented in this paper were obtained taking into account 3D variations in the dynamic viscosity of synovial fluid, particularly random variations crosswise the film thickness for non-Newtonian synovial fluid properties. According to the authors’ knowledge, the obtained results are widely applicable in spatiotemporal models in biology and health science.

2

Designing and manufacturing of customized human bone endoprostheses and orthosis devices

Borkowski Pa., Borkowski P., Dietrich M., Domański J., Grygoruk R., Haraburda M., Kędzior K., Pawlikowski M., Skalski K., Skoworodko J., Szymczak B.

Biocybernetics and Biomedical Engineering

|

2007

|

Vol. 27, no. 1-2

95-104

EN

In the paper, designs of endoprostheses and orthosis devices are presented. The endoprostheses of various joints have been designed, i.e. those of the elbow joint, hip joint, knee joint and intervertebral disc. The process of design and that of manufacturing are also shown in details, as well as certain results of numerical simulations of bone behaviour after implantation. It has to be emphasised that the designed prostheses have been successfully implanted. Clinical observations indicate a proper load transfer from the prosthesis to the bone (slight bone resorption) and give good predictions as to the endoprosthesis functionality. Also some designs of orthosis devices, which facilitate paralysed people’s life, are shown.

3

Modelling of the joint kinematics in the external fixation

Jasińska-Choromańska D., Choromański W.

Zeszyty Naukowe Politechniki Poznańskiej. Maszyny Robocze i Transport

|

2002

|

Nr 54

109-114

EN

Methods of healing fractures belong undoubtedly to the oldest group in the history of medicine. Yet, there are still carried out intensive studies related to searching for new methods as well as perfecting of the existing ones. One of them is unquestionably the external osteosynthesis with application of external orthopaedic fixators. It has been well known for a long time that providing micro-movements within the interstice of the fracture favours the progress of the bone union processes by stimulating growth of the callus. The motion is very significant while healing joint fractures or periarthric fractures. Because of a difficulty in reflecting kinematics of the knee joint for the purpose of external fixation, the paper presents a proposal of an analytic-experimental method that allows for a simple achievement of this goal.

PL

Praca poświęcona jest modelowaniu kinematyki stawów ludzkich. Celem badań jest projektowanie elementów ortopedycznych stabilizatorów zewnętrznych , które mogą odwzorowywać ruch stawów ludzkich. Szczególna uwaga zwrócona została na staw kolanowy. Stabilizatory wyposażone w takie układy znacząco przyspieszają zrost i eliminują powikłania w leczeniu złamań okołostawowych.

4

The method of solution for hydrodynamic lubrication by synovial fluid flow in human joint gap

Wierzcholski K.

Control and Cybernetics

|

2002

|

Vol. 31, no 1

91-116

EN

The paper shows a method of solution of systems of partial differential non-linear, second order equations for synovial axial-symmetrical and unsymmetrical fluid flow in curvilinear orthogonal coordinates between two bone surfaces in human joint gap. Theorems are formulated, describing unification method of solutions of partial differential non-linear equations of synovial fluid flow.