This study was performed to investigate the modulatory effects of two prototypes of Panax ginseng saponin fractions, 20(S)-protopanaxadiol saponins (PDS) and 20(S)-protopanaxatriol saponins (PTS), on the induction of inflammatory mediators in lipopolysaccharide (LPS)-treated RAW264.7 murine macrophage cells. For this purpose, RAW264.7 cells were treated with LPS (10 μg/ml) before, after, or simultaneously with PDS or PTS (150 μg/ml), and the released level of nitric oxide (NO) and expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were evaluated. When RAW264.7 cells were treated with LPS and ginseng saponin fractions simultaneously for 24 hr, PTS, compared to PDS, more strongly attenuated the NO production induced by LPS treatment. When the cells were pretreated with LPS for 2 hr followed by PDS or PTS treatment for 24 hr, both ginseng saponins strongly reduced NO release. The pretreatment of RAW264.7 cells with PDS or PTS for 2 hr followed by LPS treatment for 24 hr significantly attenuated the LPS-induced production of NO. PTS showed stronger inhibitory potency to NO generation than PDS. Our western blot experiment showed that both PDS and PTS (150 μg/ml) also significantly down-regulated the expressions of iNOS and COX-2 induced by LPS treatment. Our results suggest that both PDS and PTS possess strong protective effects against LPS-stimulated inflammation and that their protective effects are mediated by the suppression of NO synthesis via down-regulation of pro-inflammatory enzymes, iNOS, and COX-2 in the RAW264.7 cells.
-While the chirp signal is extensively used in radar and sonar systems for target decision in wireless communication systems, it has not been widely used for positioning in indoor environments. Recently, the IEEE 802.15.4a standard has adopted the chirp spread spectrum (CSS) as an underlying technique for low-power and low-complexity precise localization. Chirp signal based ranging solutions have been established and deployed but their ranging performance has not been analyzed in multipath environments. This paper presents a ranging performance analysis of a chirp signal and suggests a method to suppress multipath error by using a type of non-linear chirp signal. Multipath ranging performance is evaluated using a conventional linear chirp signal and the proposed non-linear chirp signal. We verify the feasibility of both methods using two-ray multipath model simulation. Our results demonstrate that the proposed non-linear chirp signal can successfully suppress the multipath error.
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