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Biomedical subjects

L Stevens

Publications and source records attributed to L Stevens.

At least 199 records · Page 11Linked to original sources
PubMed1976

Heat treatment of cast restorations.

A survey of commercial dental laboratories in Brisbane indicates that hardening heat treatment of cast restorations, while not always prescribed by the dentist, is performed in most dental laboratories.

Australia↗
PubMed1975

Smoking and pregnancy.

Smoking is associated with decreased fertility in both males and females, an increased abortion rate, lowered birth weight, an increased still birth rate and probably an increased neonatal death rate. There is also a reduced incidence of maternal hypertension (although the babies are at even greater risk), an increased incidence of ante-partum haemorrhage, impaired brain development and possible teratogenic effects. These effects can be reversed if the mother gives up smoking in pregnancy.

Animals↗
PubMed1975

Retention with specific and mechanical adhesive lutes.

Attention is drawn to some of the fundamental differences between retention afforded by specifically adhesive and mechanically adhesive lutes. Terms are defined and conclusions drawn regarding the present status and potential of polyacrylate cements.

Acrylates↗
PubMed1975

The properties of four dental cements.

Tests on 4 cements showed no significant difference in the retentive property of zinc phosphate and polycarboxylate cements but significant differences existed between these and two zinc oxide eugenol (modified) materials. Polycarboxylate cement was the only material which fractured partially or wholly within the cement film and the zinc oxide eugenol modifications mostly adhered to the inlay.

Adhesiveness↗
PubMed1975

Comparison of impact strength of joints made with four dental cements.

Tests on 4 cements showed the impact strength of joints between gold and tooth structure varied somewhat with the surface roughness and cementing force. Polycarboxylate provided stronger joints although the results were variable. Little difference was found between zinc phosphate, zinc oxide-eugenol with polymethyl methacrylate, and zinc oxide-eugenol with ortho ethoxybenzoic acid.

Adhesiveness↗
PubMed1975

Prolongation of allografts in animals with a new agent: tilorone.

Tilorone, a synthetic amino-alkoxyflorenone, has been demonstrated to prolong allografts in rats and dogs. Tilorone, in combination with low dose non-specific immunosuppression, appears to have an additive effect. Tilorone's mechanism of action is unclear at this time but may involve a combination of specific T lymphocyte depletion and interferon induction.

Animals↗
PubMed1973

Determination of asparagine, glutamine and pyrrolidonecarboxylic acid in total enzymic hydrolysates of peptides and glycopeptides by gas-liquid chromatography.

A new procedure for the qualitative and quantitative determination of asparagine, glutamine and pyrrolidonecarboxylic acid in total enzymic hydrolysates of peptides and glycopeptides based on g.l.c. has been developed. Under the conditions of esterification and trifluoroacetylation N-trifluoroacetylaspartic acid mono-n-butyl ester was formed from asparagine and N-trifluoroacetylglutamic acid mono-n-butyl ester from both glutamine and pyrrolidonecarboxylic acid. To distinguish between the latter two compounds, the esterification was carried out at room temperature yielding 30% of esterified pyrrolidonecarboxylic acid but less than 1% of esterified glutamine. In extending the g.l.c. of amino acids, the previously unknown positions in the g.l.c. elution pattern of the following amino acids could also be reproducibly determined: carboxymethylcysteine, homoserine, hydroxylysine and in-methyl-lysine. Further, certain glycopeptides were investigated and the artifacts due to their carbohydrate moieties were determined.

Amino Acids↗
PubMed1972

The location of spermine in bacterial ribosomes as indicated by 1,5-difluoro-2,4-dinitrobenzene and by ethidium bromide.

1. When the binding of ethidium bromide to rRNA is measured both in the presence and in the absence of spermine, by spectrophotometric titrations, by gel filtration, or by the changes in fluorescence intensity, spermine competes with ethidium bromide for sites on the rRNA; under the conditions used in these experiments ethidium bromide is bound to the double-stranded regions of rRNA. 2. When an excess of ethidium bromide is added to ribosomes from Bacillus stearothermophilus approx. 80% of the endogenous spermine is displaced from the ribosomes. 3. [(14)C]Spermine is fixed to ribosomes by either formaldehyde or 1,5-difluoro-2,4-dinitrobenzene. Most of the [(14)C]spermine, fixed to ribosomes by 1,5-difluoro-2,4-dinitrobenzene, attaches to the ribosomal protein. 4. It is concluded that most of the endogenous spermine is bound to the double-stranded RNA in ribosomes, and that some of these double-stranded regions to which spermine is attached also have ribosomal proteins bound to them.

Bacillus↗