Adaptive bone-remodeling theory applied to prosthetic-design analysis

The subject of this article is the development and application of computer-simulation methods to predict stress-related adaptive bone remodeling, in accordance with ‘Wolff's Law’. These models are based on the Finite Element Method (FEM) in combination with numerical formulations of adaptive bone-remodeling theories.\ud \ud In the adaptive remodeling models presented, the Strain Energy Density (SED) is used as a feed-back control variable to determine shape or bone density adaptations to alternative functional requirements, whereby homeostatic SED distribution is assumed as the remodeling objective.\ud \ud These models are applied to investigate the relation between ‘stress shielding’ and bone resorption in the femoral cortex around intramedullary prostheses, such as used in Total Hip Arthroplasty (THA). It is shown that the amount of bone resorption depends mainly on the rigidity and the bonding characteristics of the implant. Homeostatic SED can be obtained when the resorption process occurs at the periosteal surface, rather than inside the cortex, provided that the stem is adequately flexible

A detailed comparison of experimental and theoretical stress-analysis of a human femur

Experimental strain-gauge and theoretical stress analysis methods are used to evaluate the mechanical behavior of the femur as a structural element under loading. It is shown that when the cortical bone material is assumed to behave linear elastic, homogeneous and transversely isotropic, excellent agreement between experimental results and theoretical predictions is obtained. Also that the bone shaft can with reasonable approximation be represented by an axisymmetric model, even when intramedullary hip joint prostheses are present. The implications of these results for the analysis of intramedullary bone-prosthesis structures are discussed

A Case of Primary Squamous Cell Carcinoma of the Liver Arising in a Solitary Cyst

A case of primary squamous cell carcinoma in a pre-existing hepatic cyst is presented. A review of the literature suggests that this rare type of liver tumor tends to arise from solitary, nonparasitic cysts, lined with squamous epithelium. Effective therapy is not available, the prognosis is grave

De taal van het beeld:Lucebert tekenaar - dichter

The Language of the Image: Lucebert draughtsman – poetThe poetry of the multi-talented artist Lucebert (1924-1994) has been the subject of numerous studies, discussions and even polemics. By contrast, the few studies dedicated to his extensive pictorial oeuvre pale into insignificance. The cross-fertilization between his visual and poetic oeuvre has so far received little or no scholarly attention.The Language of the Image: Lucebert draughtsman - poet is an attempt to connect both sides of Lucebert's artistry and to pay equal attention to the visual and the poetic work, in order that they may elucidate each other. The focus is on the early period, i.e. the published and unpublished poems up to 1966, and the drawings from the period between 1940-1965.The research shows that drawing, painting and writing poetry were not separate worlds for Lucebert. Many similar themes can be found in his drawings and in his poems. In addition, the particular visual structure of the metaphors in his poetry shows that he is a poet with the eye of a draughtsman. In the discussions about the meaning of Lucebert's "corporal language", this aspect has so far been overlooked. An essential element in Lucebert's work is his constant play with paradox and ambiguity. Are these the weapons of self-defence? Or even the expression of an existential self-doubt related to his wartime past about which he has kept silent? Due to the lack of sufficient data at present, this question cannot be answered. A closer study of Lucebert's formative years as an artist during the period 1940-1950 is indispensable in order to do full justice to his impressive artistic legacy