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Biomedical subjects

J Arends

Publications and source records attributed to J Arends.

At least 325 records · Page 18Linked to original sources
PubMed1975

Morphology and size-distribution of sound and acid-treated enamel crystallites.

Citric acid dissolves crystallites of enamel by initially etching out approximately hexagonal holes in the core of the crystallites, parallel to their long axis. Such acid-treatment influences the crystallite diameter only slightly since the distribution of the diameters of crystallites with a hollow core is not essentially different from those found in sound enamel. In both cases, the average diameter is 37 nm. Crystallites having a central defect and an outer diameter of about 40 nm are split into two parts of approximatley 15 nm in diameter following acid treatment. The central defect is caused exclusively by the acid and not by damage from the electron beam, nor by a combination of acid treatment and electron beam damage.

Citrates↗
PubMed1975

HPO2-4 content in enamel and artificial carious lesions.

The HPO2-4 and CO2-3 content was determined in sound enamel and in material collected from artificially produced carious lesions. The method described shows that the HPO2-4 content can be determined from the 875 cm(-1) infrared absorption band if correction for the CO2-3 contribution are made. The I.R. spectra show that the HPO2-4 content in sound human or bovine enamel is about 5% by weight. In artificially produced carious lesions (pH=4.0), the HPO2-4 content is in the order of 15 wt%. Most likely, the HPO2-4 ions in sound and carious enamel have a different enviroment.

Animals↗
PubMed1975

Non-identical reaction of undissociated HCG and HCG-beta subunit with anti-HCGbeta serum.

Based on gel-filtration experiments, estimates of the content are given of undissociated human chorionic gonadotrophin (HCG) and HCG-beta subunit in HCG preparations. Radioimmunoassay of three HCG preparation using an antiserum against HCG-beta subunit showed that the slope of displacement curves was dependent on the ratio of HCG-beta subunit to undissociated HCG, the slope being steeper (negative) with increasing ratio. The implication of this observation on the choice of a suitable standard for HCG-beta radioimmunoassay is discussed.

Chorionic Gonadotropin↗