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Biomedical subjects

A B Strong

Publications and source records attributed to A B Strong.

12 recordsLinked to original sources
PubMed1990

Applications of three-dimensional display techniques in medical imaging.

This paper outlines some of the current uses of three-dimensional techniques in medical imaging applications and their potential for the future. As an example, three-dimensional imaging is described using a CT scanner, as it applies to a case involving craniofacial surgery. This includes defining the relationship between the requirements on the data acquisition system, as well as the specification of the hardware and software for the display. A currently used algorithm is described for the display of surfaces as a function of local position, orientation of the surface and the position of a virtual light source. This includes the use of transparency and cut plane greyscale techniques, in addition to the display of the surfaces. A speculation is made regarding the use of a three-dimensional display as the standard viewing mode in CT, with slice and multiplanar imaging as submodes.

Algorithms↗
PubMed1988

Physical and hydrodynamic factors affecting erythrocyte adhesion to polymer surfaces.

Using a flow cell design which ensures fully developed laminar flow, the influence of various hydrodynamic and physical factors in determining the extent of erythrocyte adhesion to various polymer surfaces has been examined. Specifically we have investigated the effect of exposure time, flow rate, erythrocyte concentration, and substrate surface tension on the extent of erythrocyte adhesion. The results indicate: (1) the extent of erythrocyte adhesion is most extensive on the more hydrophobic surfaces; (2) the rate of adhesion is higher on the more hydrophobic surfaces; (3) saturation coverage occurs after 7-10 min of exposure to the erythrocyte suspension for all substrates examined. No "lag-time" in the onset of adhesion was observed; (4) The level of saturation depends on the bulk erythrocyte concentration, increasing with increasing cell concentration; (5) the extent of adhesion decreases with an increase in flow rate; and (6) substrate surface defects such as roughness have a major effect on the pattern of erythrocyte adhesion.

Biocompatible Materials↗
PubMed1987

Theoretical and experimental analysis of cellular adhesion to polymer surfaces.

An exact discrete numerical solution to the Grabowski model for predicting cell adhesion to polymer surfaces is discussed. The solution technique allows the possibility of taking into account cell-cell interactions within the flow situation and the multistep process involved in thrombus formation. The proposed solution also allows modification of the wall reaction rate model into a two species reaction rate which distinguishes between the kinetics of contact adhesion and irreversible adhesion. The solution allows determination of effective diffusivity (De) and surface reaction rate (k) constants. Use of the model to examine available experimental data results in the following conclusions: (1) static or dynamic cell adhesion cannot be considered to be diffusion limited; (2) for flow conditions De is a monotonically increasing function of shear rate; (3) under static, i.e., zero flow conditions, De appears to be markedly larger than for flow conditions.

Cell Adhesion↗
PubMed1982

Effect of surface roughness on platelet adhesion under static and under flow conditions.

Normal blood clots when exposed to surfaces other than endothelial. Various unsuccessful attempts have been made to find a synthetic material that is compatible with blood. Both platelets and clotting factors are involved in thrombosis at foreign surfaces. The authors are concerned with platelet adhesion as a first step in thrombus formation. The determination of the number of platelets adhering per unit area, therefore, appears to be a useful criterion for the choice of appropriate biomaterials contacting blood. However, laboratory tests are often carried out with specially prepared, well-defined biomaterials with a smooth surface, whereas biomaterials in clinical use may have a variable degree of roughness. In this paper the authors present data on platelet adherence to a hydrophilic (glass) and to a hydrophobic (silane) material, with smooth and rough surfaces. Additional data are presented that document the extent of platelet adhesion to a wide range of smooth polymer materials having a large variation in surface hydrophobic quality. There was no difference in platelet adherence between the smooth and rough surfaces when tested under static conditions. When the surfaces were tested in a laminar flow cell, the addition of roughness caused a decrease in platelet adhesion on the hydrophilic surface and an increase in platelet adhesion on the hydrophobic surface.

Animals↗
PubMed1978

United States population dose estimates for iodine-131 in the thyroid after the Chinese atmospheric nuclear weapons tests.

Analysis of samples collected within the United States after the Chinese atmospheric nuclear weapons tests of 26 September and 17 November 1976 indicates that the radiation dose to the thyroid from iodine-131 in milk was predominant. A U.S. population dose to the thyroid of 68,000 man-rads was calculated for the iodine-131 fallout. The four excess thyroid cancers that are estimated to occur as a result of the September test during the next 45 years will be masked by the 380,000 cases of thyroid cancer which are expected to occur in the United States from all causes during the same interval.

Adult↗