Quantitative determination of taper adequate to provide resistance form: concept of limiting taper.
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Dental Cavity Preparation↗
Biomedical subjects
M J Calverley
Publications and source records attributed to M J Calverley.
Effect on the fit of removable partial denture frameworks when master casts are treated with cyanoacrylate resin.
Master casts of improved dental stone were made from irreversible hydrocolloid impressions of a metal model. Half of the master casts were treated with cyanoacrylate resin and half were untreated controls. They were sent to a dental laboratory for framework fabrication. The returned frameworks were examined for acceptability and their completeness of seating was determined. The frameworks fabricated on the treated master casts fit significantly better than the controls. The improved seating may be attributed to an increased surface hardness, increased abrasion resistance, and improved surface morphology, but further study is necessary.
Cyanoacrylates↗
N-(functionalized alkyl) derivatives of 6-aminopenicillanic acid: a new series of specific inhibitors of beta-lactamase from Enterobacter cloacae P99.
Eight of nine new N-alkylaminopenicillanic acids (7a approximately c, e approximately j), prepared via efficient direct monoalkylation reactions, were found to be specific inhibitors of cephalosporinase P99 with IC50 less than or equal to 4 mg/liter, while representative corresponding S-oxidized derivatives were less active.
Anti-Bacterial Agents↗
Novel side chain analogs of 1alpha,25-dihydroxyvitamin D(3): design and synthesis of the 21,24-methano derivatives.
The syntheses of the new 21,24-methano derivatives of 1alpha,25-dihydroxyvitamin D(3) [viz. 1(S),3(R)-dihydroxy-17(R)-(1',4'-cis-(4'-(1'-hydroxy-1'-methylethyl)-cyclo-hexyl))-9,10-seco-androsta-5(Z),7(E),10(19)-triene (MC 2108) and its (1',4'-trans)-isomer (MC 2110)] are described. The key step is the establishment, by Diels-Alder reaction on a CD-ring side chain diene intermediate prepared from vitamin D(2), of a 1,4-disubstituted cyclohexene moiety in the side chain. Hydrogenation to a 1:1 mixture of cis and trans cyclohexane derivatives and separation of the two series at a stage prior to the standard Horner-Wittig coupling with the (Hoffmann-La Roche) ring-A building block were other important steps in the syntheses of the target analogs. The relative configurations of intermediates were assigned by NMR spectroscopy. MC 2108 and MC 2110 are of interest as conformationally locked side chain derivatives to probe the receptor interactions of not only the parent vitamin D hormone but also its biologically active symmetrical 'double side chain' analog [21-(3'-hydroxy-3'-methylbutyl)-9,10-seco-cholesta-5(Z),7(E),10(19)-triene-1(S),3(R),25-triol (MC 2100)], 'both' side chains of which can formally be traced out in the new analogs. The preferred conformations, inferred from an analysis of (13)C-NMR characteristics, notably the chemical shift of C-17 in a series of analogs, to have the tertiary alcohol (1'-hydroxy-1'-methylethyl) substituent equatorial on the cyclohexane chair, are confirmed by molecular modeling.
Animals↗