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Biomedical subjects

S A Jackson

Publications and source records attributed to S A Jackson.

5 recordsLinked to original sources
PubMed1979

The fibrous structure of bone determined by x-ray diffraction.

The fibrous structure of both primary and secondary type cortical bone is determined. The three dimensional fibrous orientation is expressed quantitatively by pole figures of the (002) diffraction. Whilst both types of bone exhibit one major axis of fibrous orientation which is aligned on average with the long axis of the femur, primary type bone exhibits a planar orientation which is consistent with a fibrous spread within the laminations but not from one lamination to the next. Secondary type bone exhibits a degree of preferred orientation with rotational symmetry about the main fibre axis.

Aged↗
PubMed1979

The optimum illuminance level for clinical electro-oculography.

The variation of Arden Index with the level of illuminance used for the light adaptation phase in electro-oculographic examination is investigated. A level of 300 Lux is suggested as producing maximum response and minimum patient discomfort. Situations where greater levels of illuminance are specifically required are discussed.

Adult↗
PubMed1978

The morphology of bone mineral crystals.

Electron microscopical observations of the size and shape of bone mineral crystallites have not been in complete agreement with X-ray diffraction findings. The two prevalent viewpoints consider bone mineral crystals to be either rod, or plate like in habit. There appears to be agreement that the smallest dimension of the crystals is about 5 nm, but there is discrepancy in the reported c-axial lengths. The method of dark field imaging is used to obtain a quantitative measurement of the c-axial length distribution in rabbit, ox and human bone: mean c-axial lengths 32.6 nm, 36.2 nm and 32.4 nm, respectively, show no significant difference at the 5% level to the mean c-axial length measured by X-ray line broadening. Both bright and dark field images strongly suggest that bone mineral has a plate like form. Reasons for past discrepancies are discussed.

Animals↗