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Biomedical subjects

H Zinner

Publications and source records attributed to H Zinner.

8 recordsLinked to original sources

Determining the kinematic parameters of a moving imaging sensor by processing spatial and temporal intensity changes.

A method is presented that determines the motion parameters of an imaging sensor by evaluating the spatial and temporal intensity changes in the image plane. It is not necessary to compute the optical flow. If the environment in the field of view is described parametrically, constraint equations between the kinematic parameters and the intensity changes can be derived. Linear solutions of these equations are the so-called pure parameters, which are nonlinear functions of the motion parameters. These quantities are the roll, pitch, and yaw rate, the angle of attack and the angle of yaw, and orientation parameters. They can be obtained directly by solving a 3 X 3 eigenvalue problem. The algorithm was implemented and applied to artificial and natural image sequences. An error and covariances analysis shows that the method is robust and accurate enough for autonomous navigation.

Algorithms

Copper inhibits pressor responses to noradrenaline but not potassium. Interactions with prostaglandins E1, E2, and I2 and penicillamine.

Low concentrations of copper inhibited responses to norepinephrine and angiotensin (IC50 3 X 10(-6) M) but not to potassium in rat mesenteric vascular preparations perfused either with buffer or indomethacin and prostaglandin (PGE2). The dose-response curve was not shifted by indomethacin, imidazole, or PGE2 but was moved to the right by 2.8 X 10(-11) M PGE1 and to the left by 2.8 X 10(-7) M PGE1. These effects of copper are similar to the effects of PGI2 in the preparation. Copper moved the PGI2 dose-response curve against noradrenaline in parallel to the left, suggesting that the two were interacting at some point. Penicillamine, which may stimulate PGE1 synthesis, had PGE1-like interactions with the copper effect, suggesting that its value in Wilson's disease may be partly due to antagonism of the biological action of copper as well as to its copper-chelating properties.

Animals

Dopamine enhances the action of prolactin on rat blood vessels. Implications for dopamine effects on plasma prolactin.

It has been claimed that dopamine enhances peripheral uptake of prolactin. Dopamine at 2.1 x 10(-9)M, a concentration which had no effect by itself, enhanced both the potentiation of rat mesenteric vascular reactivity caused by 50ng/ml ovine prolactin and the inhibition of reactivity caused by 500ng/ml prolactin. These observations are consistent with the proposal that dopamine can interact peripherally with prolactin.

Animals