Dark Substance
Mostrando 13-16 de 16 artigos, teses e dissertações.
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13. Prostaglandin D2, a cerebral sleep-inducing substance in monkeys.
The sleep-inducing effect of prostaglandin D2 (PGD2) was studied in five conscious male rhesus monkeys (Macaca mulatta) maintained in a 12-hr light/dark cycle. PGD2 was infused into the lateral or the third ventricle of the cerebrum slowly and continuously for 6 hr in the light period. Infusion of PGD2 into the lateral ventricle at 15-2250 pmol/min induced n
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14. Metabolism of Oat Leaves during Senescence: V. Senescence in Light 1
A comparison has been made of the progress of senescence in the first leaf of 7-day-old oat plants (Avena sativa cv. Victory) in darkness and in white light. Light delays the senescence, and intensities not over 100 to 200 ft-c (1000-2000 lux) suffice for the maximum effect. In such intensities, chlorophyll loss and amino acid liberation still go on in detac
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15. An ultrastructural study of ependymal cell differentiation during lizard (Gallotia galloti) midbrain development.
Ependymal cell differentiation was examined in the lizard Gallotia galloti from E31 to adult. From E31 to E34 only one type of cell could be identified making up the pseudostratified columnar neuroepithelium but by E35 to E37 three types of ependymal cell were present. The first type was a narrow, elongated, columnar cell containing rough endoplasmic reticul
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16. The anatomy and development of the claws of Xenopus laevis (Lissamphibia: Anura) reveal alternate pathways of structural evolution in the integument of tetrapods
Digital end organs composed of hard, modified epidermis, generally referred to as claws, are present in mammals and reptiles as well as in several non-amniote taxa such as clawed salamanders and frogs, including Xenopus laevis. So far, only the claws and nails of mammals have been characterized extensively and the question of whether claws were present in th
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