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Biomedical subjects

R L Clarke

Publications and source records attributed to R L Clarke.

At least 127 records · Page 7Linked to original sources
PubMed1969

Total synthesis of dl-19-nor-16,17-dehydroprogesterone.

dl-2-(7,11-Dimethyl-3,7,11 - trans,trans-dodecatrienyl)-3-methyl-cyclopent-2-enol was prepared by reduction of the corresponding ketone. This tetraenol, on treatment with trifluoroacetic acid, underwent stereoselective cyclization to give dl-3,17-dimethyl-A-nor-D-homoestra-3,16-diene. This tetracyclic material was readily converted, by oxidative cleavage to the bicyclic triketo aldehyde followed by a double aldol cyclization, into dl-19-nor-16,17-dehydroprogesterone.

Chemical Phenomena↗
PubMedDate not supplied

Dental materials: 1995 literature review.

This critical review of the published literature on dental materials for the year 1995 has been compiled by the Dental Materials Panel of the United Kingdom. It continues the series of annual reviews started in 1973 and published in the Journal of Dentistry. Emphasis has been placed upon publications which report upon the materials science or clinical performance of the materials. The review has been divided by accepted materials classifications (fissure sealants, glass polyalkenoate cements, resin composites, dentine bonding, dental amalgam, endodontic materials, casting alloys, investment materials, resin-bonded bridges and ceramo-metallic restorations, all ceramic restorations, denture base and soft lining materials, impression materials, dental implants, orthodontic materials and biomechanics). Three hundred and thirty articles published in 68 titles have been reviewed.

Biomechanical Phenomena↗
PubMedDate not supplied

The use of Compton scattered gamma rays for tomography.

A method of tomographic imaging of soft tissues by the use of Compton scattering of gamma rays is described. A highly collimated source (800 Ci of 60Co) and collimated detectors are used. Spatial resolutions of the order of 0.5 cm or better are achieved, with a density resoution of 2.0% to 4%. Experimental tests with dogs have shown internal organs in sagittal, coronal and transverse section. No contrast or radioactive material is required. Tests have shown that the regional dose for humans will be about 0.25 to 1 rad for one scan.

Animals↗