No abstract

A novel ureidobromophenol, rhodomelin A (1), was characterized from Rhodomela confervoides. Its structure was elucidated by spectroscopic analysis. Both enantiomers of 1 were synthesized using a convergent strategy starting from d/l-pyroglutamic acids, respectively, allowing assignment of the R-configuration for the naturally occurring isomer by chiral HPLC analysis. Rhodomelin A represents the first example of a naturally occurring ureidopyrrolidone alkaloid incorporating a γ-aminobutyric acid unit. The scavenging activity of 1 toward DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate)) radicals was assayed.

A scheme of HARQ re-sending nodes selection for relay network is purposed in this paper. The study is focused on how to select relay node with minimum resending power under the particular required receiving performance of the destination node. The candidate relay nodes are divided into several regions according to the difference of resending power required. With this selection scheme, the diversity gain and high system power efficiency can all be achieved. The effectiveness of this scheme is proved by the simulation results.