Spot size reduction in coupling of laser to micromanipulator in laser microsurgery by fiberoptic link.

Background And Objective: In coupling laser with micromanipulator through fiberoptics, the resulting diameter of the spot is limited by the laws of geometrical optics, because of the high numerical aperture (N.A.) of fiberoptic radiation.

[Certain parameters of beta-carotene metabolism in the rat].

Concentration of retinoids was decreased from 24.5 micrograms/100 ml to 13.5 micrograms/100 ml of blood serum in rats with ageing, during 2-11 months; these rats were maintained on a standard ration.