No abstract

SUMMARYWe studied the effect of sleep excess on the sleep-wakefulness pattern of rats.Subarachnoid infusion of prostaglandin D 2 or the adenosine A 2a receptor agonist CGS21680 effectively induced slow wave sleep (SWS) for the first 12 h of the nighttime period, whereas they did not induce sleep during the following 24 h of infusion. An increase in the amount of wakefulness was seen during the last 12 h of prostaglandin D 2 infusion. The amounts of wakefulness strongly increased during the following 36-h recovery period. Rebound wakefulness was extraordinarily strong after the cessation of CGS21680 infusion, reaching almost complete insomnia during the night-time. Treatment of animals with prostaglandin D 2 overnight, following by treatment with CGS21680 on the next night, resulted in the strongest induction of wakefulness rebound. During the rebound period, the amount of wakefulness reached up to 50 min per hour in the daytime. Rebound of wakefulness depended on the amounts of preceding SWS induced by infusion of prostaglandin D 2 for 6 or 12 h and of CGS21680 for 12 h. The larger the amount of SWS, the larger the amount of the following rebound of wakefulness. Rebounds of wakefulness occurred as a result of decrease in SWS amounts, whereas paradoxical sleep amounts did not change. Desensitization of adenosine A 2a receptors and accumulation of prostaglandin E 2 may be involved in the production of strong wakefulness rebound following relatively long treatments (more than 12 h) with prostaglandin D 2 or CGS21680.

For assembly of reinforcing bars embedded in electrolyte like concrete, space-averaged non-local analysis for electric potential is proposed and the anodic and cathodic polarization reactions are formulated in association with the exchange of electric charge between steel reinforcing bars and the electrolyte as matrix. In order to verify the proposed scheme like smeared crack modeling of cracked concrete mechanics, transparent sodium poly-acrylate superabsorbent polymer with calcium hydrate solution was made so that we may identify the location of anodic and cathodic reactions of reinforcement at regular time intervals. The analytically predicted locations of corrosion were compared with the experiments, and its functionality of non-local formulation was verified and its applicability was experimentally examined.

No abstract