Bioactivity of Marine Natural Product Xyloketals

: Oceans can play a major role in supplying life-saving medicines in the world in future. Although considerable progress has been made in finding new medicines from marine sources, large efforts are still necessary to examine such molecules for clinical applications. Xyloketals are an important group of natural products with various powerful and prominent bioactivities such as inhibition of acetylcholine esterase, antioxidant activity, inhibition of L-calcium channels, radicalscavenging behavior, suppression of cell proliferation, reduction of neonatal hypoxic-ischemic brain injury, etc. This review describes the isolation and structural characterization of all xyloketal natural products giving major emphasis on their bioactivity.

Male accessory gland factors increased sex pheromone titres in the glands of Spodoptera litura female moths by inhibiting calling behavior

Moths are the most widely studied example of pheromones in animals. However, little is known about the mechanism of intrasexual and mating-related intersexual regulation of pheromone production and release in female moths. Our previous studies in Spodoptera litura found that mating induced a higher sex pheromone titre in the pheromone gland (PG) and mating or male accessory gland (MAG) extract suppressed female calling behavior. We therefore hypothesize that the inhibition of female calling behavior by mating or MAG factors likely suppresses the release of sex pheromones and thus results in a higher pheromone titre in the PG. To test this hypothesis, in the present study, we introduced an artificial calling behavior suppression treatment by gently knocking on and shaking the testing boxes contained moths once every 10 minutes. Results show that this treatment significantly increased pheromone titres in virgin or saline injected virgin females, and the increase rates are similar to those of mating and MAG extract treated ones. These results have suggested that the increase of sex pheromone titer in the female PG after mating in S. litura is due to the inhibition of female calling behavior by MAG factors. Moreover, results of this study also suggest that female calling behavior is positively correlated to pheromone release and likewise, the calling behavior and sex pheromone release in S. litura females are directly under the neural control, and modulated by molecular and environmental factors.

A Mechanism for Recognizing and Suppressing the Emergent Behavior of UAV Swarm

Similar to social animals in nature, UAV swarm is also a complex system that can produce emergent behavior. The emergent behavior of UAV swarm in specific airspace is undoubtedly the act that the defense side does not expect to see; therefore, recognition and suppression of the emergent behavior of UAVs swarm are needed. Based on the analysis of the UAV swarm emergent behavior mechanism, by adoptingf-divergence method, UAV swarm emergent behavior was quantified, and a rapid recognition mechanism of emergent behavior has been established, thus, making preparation for the suppression of the emergent behavior. In the academic circle, for the first time, in accordance with heuristic rules governing the algorithms of UAV swarm suppression, principle of emergent behavior suppression has been proposed, failure judgment model of UAV swarm control under interference conditions has been constructed, the stability of UAV swarm has been analyzed, and the combat command process of UAV swarm based on OODA loop has been put forward. Through the simulation, the comparison of information entropy andf-divergence based emergence measurement method has been made, andf-divergence based method has some advantages for measuring the emergence of UAV swarm. From the analysis and discussion of the inhibitory effect on swarm flocking behavior under different interference intensity and timing, conclusion has been drawn that comprehensive suppression on the premise of correct recognition of flocking behavior is the best strategy fighting against UAV swarm emergent behavior.

Elimination of Self-Injurious Behavior in a Profoundly Retarded Adolescent Using Intermittent Time-Out, Restraint, and Blindfold Procedures

Alternative strategies for reducing self-injurious behavior are needed in order to provide effective service to clientele for whom such behavior is a serious problem. A procedure involving the intermittent presentation of time-out, restraint, and blindfolding produced complete suppression of self-slapping in a profoundly retarded adolescent. A variable-ratio two schedule of time-out and physical restraint contingencies was effective in reducing and maintaining a low level of self-abusive behavior. While some of the treatment effect was lost during and after exposure to a variable-ratio six schedule, the addition of a blindfold procedure to the variable-ratio two resulted in complete suppression of self-slapping. A punishment contrast effect observed during the initial return to baseline conditions was eliminated through complete suppression of the self-abusive behavior during the final intervention procedure. This behavior suppression generalized across time and settings in which the contingencies had never been applied. In addition, this suppression was associated with an increase in adaptive behavior and did not produce any undesirable collateral responding. Two-year follow-up data indicate that complete response suppression has been maintained.