摘要:

Most investigations of the material properties of bone have been concerned with the measurement of absolute values for various mechanical parameters. It can be necessary, however, to produce test samples with similar mechanical properties in order to assess the effect on these properties of particular treatments. Absolute values for these properties may not be as important as any changes observed. We describe here a new method whereby many bone test samples with very similar mechanical properties can be produced. If the femoral shaft at the diaphysis is cut in transverse section, it is possible to produce many similar shaped rings of bone. We compared the material properties of 4% ring samples with 65 beam specimens. Both were tested in three-point bending. Global estimates of coefficient of variation (CV) for each parameter were used to assess similarity within each group. All the rings had very similar ash weights (1·98%), thicknesses (1·97%), and diameters (<0·01%). Values of load/deflection of the rings were more similar than the values of Young's modulus (E) for the beams (7·06 versus 9·9%), and the maximum loads sustainable by the rings were more similar than the bending strengths of the beam (5·7 versus 13·6%). The energy absorbed by the ring samples was more consist&than the beam (14·31 versus 34·41%). We suggest that there is improved similarly in mechanical characteristics within groups of samples produced in this manner than with more conventional sample configurations.

ISSN:0309-1902    

DOI:10.3109/03091909509030263

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

We present a 3-D model for the simulation of a realistic clinical situation during magnetic stimulation. The electromagnetic problem is solved by reconstructing the inhomogeneous head tissues from magnetic resonance images and associating relative values of conductivity to each tissue. Application of Maxwell's equations in the integral form leads to an equivalent 3-D electrical network, whose solution gives the current density distribution in the brain. The high spatial resolution and rigorous electromagnetic approach make this model an accurate and useful tool for stimulator design and for estimating the efficient and safety of this clinical methodology.

ISSN:0309-1902    

DOI:10.3109/03091909509030264

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Simple methods of quantifying selected physical characteristics of angiographic catheters, which are like&to influence their in vivo performance, have been developed. The torsional stiffness (‘torque’) of catheters was measured, and tip control (‘manoeuvrability’in an angiographic phantom was studied. Both braided and unbraided catheters were investigated all having the‘headhunter’tip shape. Significant differences between measurements made at 20 and 37°C were found. Torsional stiffness was not a good predictor of performance in the angiographic phantom. Ethylene oxide re-sterilization has on&a limited effect on the physical characteristics studied.

ISSN:0309-1902    

DOI:10.3109/03091909509030265

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909509030266

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Technical Principles, Design and Safety of Joint Implants: Edited by Gottfried H. Buchhorn and Hans-Georg Willert. Hogrefe and Hu-her (Gottingen, 1994), pp. 431. Price $159, ISBN 0-88937-090-7.

ISSN:0309-1902    

DOI:10.3109/03091909509030267

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909509030268

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909509030269

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909509030270

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909509030271

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor