Generalized arterial calcification of infancy (GACI), an autosomal recessive disorder caused by mutations in the ENPP1 gene, manifests with extensive mineralization of the cardiovascular system. A spontaneous asj-2J mutant mouse has been characterized as a model for GACI. Previous studies focused on phenotypic characterization of skin and vascular tissues. This study further examined the ectopi...

We have developed an approximate method for simulating the three-dimensional contact of soft biphasic tissues in diarthrodial joints under physiological loading. Input to the method includes: (i) kinematic information describing an in vitro joint articulation, measured while the cartilage is deformed under physiological loads, (ii) geometric properties for the relaxed (undeformed) cartilage lay...

The stingray family Myliobatidae contains five durophagous (hard prey specialist) genera and two planktivorous genera. A suite of morphological features makes it possible for the hard prey specialists to crush mollusks and crustaceans in their cartilaginous jaws. These include: 1) flat, pavement-like tooth plates set in an elastic dental ligament; 2) multiple layers of calcified cartilage on th...

The lack of practicable nonlinear elastic contact models frequently compels the inappropriate use of Hertzian models in analyzing indentation data and likely contributes to inconsistencies associated with the results of biological atomic force microscopy measurements. We derived and validated with the aid of the finite element method force-indentation relations based on a number of hyperelastic...

Cartilaginous tissues, such as articular cartilage and the annulus fibrosus, exhibit orthotropic behavior with highly asymmetric tensile-compressive responses. Due to this complex behavior, it is difficult to develop accurate stress constitutive equations that are valid for finite deformations. Therefore, we have developed a bimodular theory for finite deformations of elastic materials that all...

The preoperative planning of primary tumor resections in the larynx region shall be supported by a 3D visualization of the patientspeci c anatomy and pathological situation. This requires a segmentation of the larynx cartilage structures from computed tomography (CT) datasets. In our work, we use 3D Stable Mass-Spring Models (SMSMs) for this segmentation task. Thereto, we create a speci c 3D de...

An automated approachfor measuring in situ two-dimensional strain fields was developed and validated for its application to cartilage mechanics. This approach combines video microscopy, optimized digital image correlation (DIC), thin-plate spline smoothing (TPSS) and generalized cross-validation (GCV) techniques to achieve the desired efficiency and accuracy. Results demonstrate that sub-pixel ...

Stress relaxation and structural analysis were used to investigate the zonally differentiated microstructural response to compression of the integrated cartilage-on-bone tissue system. Fifteen cartilage-on-bone samples were divided into three equal groups and their stress relaxation responses obtained at three different levels of axial compressive strain defined as low (~20%), medium (~40%) and...

Synovial joints are composed of several different kinds of tissue that interact to protect normal joint function. Three subchondral mineralized tissues can be identified-calcified cartilage, subchondral cortical bone, and subchondral trabecular bone-which are distinguished morphologically, physiologically, and mechanically. Each responds to mechanical and pharmaceutical stimuli in different way...

The protruding ear as a minor ear abnormality is found in approx. 5% of the German population and may give rise to serious emotional problems in children and also in adults. In general, the procedure used for the surgical correction of protruding ears (otoplasty) is a combination of incision, scoring and suture techniques. The choice of the surgical procedure is based on the severity of the ear...