A numerical and experimental study of RF shimming in the presence of hip prostheses using adaptive SAR at 3 T

McKee-Farrar, Charnley and Muller prostheses have been studied in a hip function simulator using a range of silicone fluids as lubricants. Frictional resistance was measured continuously while the joints were subjected to dynamic loading. It was observed that the lubricant viscosity was very important to the mode of lubrication prevailing and that for viscosities in excess of 0.1 Pas, full fluid film lubrication was achieved. At viscosities which were less than this, mixed lubrication resulted These results can be extrapolated to the clinical situation where it was found that after hip surgery for total joint replacement, the synovial fluid produced around the prosthesis had a viscosity which was less than 0.1 Pas, and therefore could not give the most advantageous lubrication in these joints in vivo.

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An experimental study of damage accumulation in cemented hip prostheses

Clinical Biomechanics ◽

10.1016/0268-0033(95)00076-3 ◽

1996 ◽

Vol 11 (4) ◽

pp. 214-219 ◽

Cited By ~ 32

Author(s):

BAO McCormack ◽

PJ Prendergast ◽

DG Gallagher

Keyword(s):

Experimental Study ◽

Damage Accumulation ◽

Hip Prostheses

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Novel methods for demonstrating osseointegration of hydroxylapatite-coated titanium hip prostheses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084478 ◽

1991 ◽

Vol 49 ◽

pp. 34-35 ◽

Cited By ~ 1

Author(s):

P. Frayssinet ◽

J. Hanker ◽

D. Hardy ◽

B. Giammara

Keyword(s):

Hip Prosthesis ◽

Ethanol Concentration ◽

Bone Matrix ◽

Electron Microscopic Examination ◽

Electron Microscopic ◽

Hip Prostheses ◽

Cellular Inclusions ◽

Microscopic Studies ◽

Diamond Saw ◽

Plasma Sprayed

Prostheses implanted in hard tissues cannot be processed for electron microscopic examination or microanalysis in the same way as those in other tissues. For these reasons, we have developed methods allowing light and electron microscopic studies as well as microanalysis of the interface between bone and a metal biomaterial coated by plasma-sprayed hydroxylapatite(HA) ceramic.An HA-coated titanium hip prosthesis (Corail, Landos, France), which had been implanted for two years, was removed after death (unrelated to the orthopaedic problem). After fixation it was dehydrated in solutions of increasing ethanol concentration prior to embedment in polymethylmethacrylate(PMMA). Transverse femur sections were obtained with a diamond saw and the sections then carefully ground to a thickness of 200 microns. Plastic-embedded sections were stained for calcium with a silver methenamine modification of the von Kossa method for calcium staining and coated by carbon. They have been examined by back-scatter SEM on an ISI-SS60 operated at 25 KV. EDAX has been done on cellular inclusions and extracellular bone matrix.

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Experimental study on the restoration from a tilt-azimuth series for improvement in resolution

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010013955x ◽

1995 ◽

Vol 53 ◽

pp. 636-637

Author(s):

Norio Baba ◽

Norihiko Ichise ◽

Syunya Watanabe

Keyword(s):

Experimental Study ◽

Spherical Aberration ◽

Incident Beam ◽

Optical Parameters ◽

Beam Tilting ◽

Illumination Method ◽

Restoration Method ◽

Illumination Mode

The tilted beam illumination method is used to improve the resolution comparing with the axial illumination mode. Using this advantage, a restoration method of several tilted beam images covering the full azimuthal range was proposed by Saxton, and experimentally examined. To make this technique more reliable it seems that some practical problems still remain. In this report the restoration was attempted and the problems were considered. In our study, four problems were pointed out for the experiment of the restoration. (1) Accurate beam tilt adjustment to fit the incident beam to the coma-free axis for the symmetrical beam tilting over the full azimuthal range. (2) Accurate measurements of the optical parameters which are necessary to design the restoration filter. Even if the spherical aberration coefficient Cs is known with accuracy and the axial astigmatism is sufficiently compensated, at least the defocus value must be measured. (3) Accurate alignment of the tilt-azimuth series images.

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