Jorrit Kabel

Learn More
Bacterial genomes contain 250 to 500 essential genes, as suggested by single gene disruptions and theoretical considerations. If this view is correct, the remaining nonessential genes of an organism, such as Bacillus subtilis, have been acquired during evolution in its perpetually changing ecological niches. Notably, approximately 47% of the approximately(More)
This study addresses the possible significance of trabecular connectivity for the mechanical quality of cancellous bone. A total of 141 cubic trabecular bone specimens collected from autopsy material from 56 individuals without any known bone or metastatic diseases were used. Age variation was in the range of 14-91 years and a wide range of trabecular(More)
The hypothesis that trabecular morphology can predict the elastic properties of cancellous bone has only partly been verified and no predictive analytical model is currently available. Such models are becoming increasingly relevant as the resolution levels of three-dimensional scanning techniques approach the size of trabeculae. This study took advantage of(More)
A method of data analysis for a set of elastic constant measurements is applied to data bases for wood and cancellous bone. For these materials the identification of the type of elastic symmetry is complicated by the variable composition of the material. The data analysis method permits the identification of the type of elastic symmetry to be accomplished(More)
Cancellous bone architecture and mechanics are intimately related. The trabecular architecture of cancellous bone is considered determined by its mechanical environment (Wolff's law), and the mechanical properties of cancellous bone are inversely determined by the trabecular architecture and material properties. Much effort has been spent in expressing(More)
A method is presented to find orthotropic elastic symmetries and constants directly from the elastic coefficients in the overall stiffness matrix of trabecular bone test specimens. Contrary to earlier developed techniques, this method does not require pure orthotropic behavior or additional fabric measurements. The method uses high-resolution computer(More)
Thiol-disulfide oxidoreductases are required for disulfide bond formation in proteins that are exported from the cytoplasm. Four enzymes of this type, termed BdbA, BdbB, BdbC, and BdbD, have been identified in the Gram-positive eubacterium Bacillus subtilis. BdbC and BdbD have been shown to be critical for the folding of a protein required for DNA uptake(More)
It would be advantageous if the mechanical properties of trabecular bone could be directly inferred from stereomorphometric parameters. For that purpose, apparent density and mean intercept length, as measures of bone mass and directionality (fabric), are commonly correlated with the elastic characteristics of bone samples, as determined in compression(More)
We aimed to highlight the relationship between age and the architectural properties of trabecular bone, to outline the patterns in which the variations in these properties take place, and to investigate the influence of the architecture on the mechanical properties of trabecular bone in growing animals. We studied 30 lambs in three age groups and 20 sheep(More)
The aim of this study was to examine the influence of response fluctuations with dyskinesia on the 24-h motor activity pattern and measures of diurnal and nocturnal activity and immobility. Motor activity was recorded during 5 successive days in 5 patients with advanced Parkinson's disease (PD) suffering from severe response fluctuations with dyskinesia, as(More)