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Biomedical subjects

V Kafka

Publications and source records attributed to V Kafka.

At least 19 recordsLinked to original sources
PubMed1995

On the mechanical function of tendon.

A mesoscopic approach is followed for mathematical modelling of the specific deformation properties of tendon. The approach starts from our general concept of modelling mechanical behaviour of heterogeneous media and assumes that the structure of tendon is optimized in such a way that it enables its adjacent muscle to work with a constant performance in the course of increasing loading (acting like a gearbox in a car). The model based on this assumption gives results that are in a very good accordance with observed properties of tendons. Clinical experience reveals that if this function of tendon is violated pathological changes appear in the respective muscle. RELEVANCE: Clarification and mathematical modelling of the mechanical function of tendon is of intellectual interest in its own right, but it is important also for cautioning surgeons against unnecessary violation of this function, and for tissue engineering aspects if tendon must be replaced.

Journal Article↗
PubMed1983

On hydraulic strengthening of bones.

Hydraulic strengthening of bones - i.e. the strengthening effect of the viscous fluid in bones - is discussed and the contradicting results of some researches concerning the existence of hydraulic strengthening are estimated. It is concluded that hydraulic strengthening exists and has an important positive effect upon the mechanical behaviour of bone, especially of cancellous bone. General features of an adequate mathematical model for the mechanical behaviour of cancellous bone are specified.

Biomechanical Phenomena↗
PubMed1983

A structural mathematical model for the viscoelastic anisotropic behaviour of trabecular bone.

The presented paper is based on the conclusions of the preceding paper (1). On the basis of a general theoretical approach to the mechanics of heterogeneous materials published earlier / (2) , (3) , (4) / macroscopic constitutive equation of trabecular bone is deduced from the description of its microstructure. For the behaviour in physiological limits trabeculae are described as elastic and the remaining material constituent as a Maxwell body. The resulting macroscopic constitutive equation comprehends tensorial internal variables and the parameters appearing in it are the constants of the material constituents constitutive equations, the respective volume fractions and special structural parameters descriptive of the geometry of composition. The system of the trabeculae as well as the system of the remaining constituent of the composite are considered to be interconnected - continuous. Explicite formulae are given for the case of transverse isotropy, but the extension to more general cases of anisotropy is well possible. The procedure of identification of the model parameters is shown and a numerical example calculated.

Adult↗
PubMed1977

The use of serial determination of blood serum glycoproteins for indirect evidence of the sensitivity and resistance of malignant tumor cells to clinical chemotherapy.

Sialic acid and mucoprotein tyrosine (MPT) as two important and sensitive indicators of blood serum glycoprotein changes were used for the dynamic follow up of the tumor growth in humans. Their determination was performed before and during chemotherapy with the aim to evaluate indirectly the sensitivity or resistance of malignant cell to the clinical chemotherapy. A total amount of 16 cases with gynecological malignancies was investigated. According to the results of the laborabory findings the patients were divided into three groups: a) with decreased values after chemotherapy, b) with no changes or increased values, c) uncertain results. The laboratory findings corresponded well with the clinical course of the disease.

Antineoplastic Agents↗