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Biomedical subjects

J Semmlow

Publications and source records attributed to J Semmlow.

5 recordsLinked to original sources

Incremental network analogue model of the coronary artery.

From Newton's equation and the continuity equation, an equivalent analogue circuit model can be derived for each small segment of the coronary arteries. Sapoznikov divided the coronary artery tree into 116 segments. By replacing each segment with its analogue circuit model, a final incremental network model was derived. The model was tested using typical physical parameters under normal conditions, as well as in the presence of coronary artery stenosis. In the case of stenosis, the arteriolar flow with and without autoregulation were compared. The model shows good agreement with the reported effects of stenoses and heart rate on coronary blood flow.

Animals

Dynamic contributions of the components of binocular vergence.

Experimental results from step stimulation of the two major dynamic components in ocular vergence showed that while fusional covergence dominated a coordinated binocular vergence movement, accomodative convergence always contributes to the dynamic response. A quantitative analysis of component dynamics, both in isolation and during coordinated movements, indicates that these components are additive at least through a portion of the movement. Two alternative hypotheses are presented for the role of accommodative convergence during the period immediately following a binocular vergence movement.

Accommodation, Ocular