AIDS Vaccine Development Agosto, Moises; Allan, Jon; Benson, Constance ...
Science (American Association for the Advancement of Science),
05/1998, Letnik:
280, Številka:
5365
Journal Article
It is well known that government R&D and private R&D have a complementary relationship. However, no previous study has provided an explanation for why that complementary relationship exists. This ...paper argues that infratechnology is the critical link between governmental and private R&D and that the observed complementarity is the result of technical complementarity at the production level between funding, infratechnology, and knowledge sharing. A theoritical framework based on this argument is developed and examined empirically for supporting evidence. Evidence of technical complementary is found as well as evidence that governmental R&D stimulates the sharing of knowledge.
We report the absence of photic retinal injury after exposing the retina to light from class 3A laser pointers for durations of up to 15 minutes. Three patients with uveal melanomas were scheduled to ...have an enucleation. Each agreed to have his or her retina exposed to laser light from a class 3A laser pointer prior to enucleation. Continuous exposure was directed to the fovea for 1 minute, to the retina 5 degrees below fixation for 5 minutes, and to the retina 5 degrees above fixation for 15 minutes. Ophthalmoscopic evaluation of the cornea, lens, and retina and fluorescein angiographic studies of the retina were conducted before, 24 hours after, and 11 days after laser exposure in the first case; before and 86 hours after exposure in the second case; and before, 96 hours after, and 15 days after exposure in the third case. Other than transient afterimages that lasted only a few minutes, we were unable to document any functional, ophthalmoscopic, fluorescein angiographic, or histologic evidence of damage to any structures of the eyes. Transmission electron microscopic studies of retinal sites targeted by the laser pointers in the second and third cases revealed ultrastructural abnormalities in the outer retina and the pigment epithelium that were similar to abnormalities seen in the retina approximately 8 mm away from the targeted sites. The risk to the human eye from transient exposure to light from commercially available class 3A laser pointers having powers of 1, 2, and 5 mW seems negligible.
Ten patients in four families with white or yellow-white granular-like deposits of the peripheral retina, consistent with the description of snowflake degeneration are reported. The granular changes ...are observable near the equatorial fundus as numerous ophthalmoscopically discrete deposits commonly up to 100 to 200 microns in size that focally thicken the retina. They can be rather evenly distributed about the entire circumference of the eye, but sometimes they may show a predilection for the inferior quadrants. The lesions need not be associated with recognizable vitreous liquefaction, vitreoretinal traction, retinal breaks, or retinal pigmentation, and in some instances the condition appears relative stable for intervals as long as five years. The similar appearance in a mother and her 9-year-old son suggests further the relative stability of the condition. In its pure form, snowflake degeneration may be an innocent dominant familial finding but when associated with other conditions such as lattice degeneration, snowflake degeneration may be of clinical significance. Affected members may have co-existing extensive white with and without pressure changes and/or lattice degeneration.
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