Shock temperature and reflectivity of precompressed H2O up to 350 GPa:Approaching the interior of planets

Using a combination of static precompression and laser-driven shock compression, shock temperature and reflectivity of H2O have been measured up to 350 GPa and 2.1×10~4 K. Here, two calibration standards were applied to enhance temperature measurement reliability. Additionally, in temperature calculations, the discrepancy in reflectivity between active probe beam wavelength and self-emission wavelength has been taken into account to improve the data’s precision.Precompressed water’s temperature–pressure data are in very good agreement with our quantum molecular dynamics model,suggesting a superionic conductor of H2O in the icy planets’ deep interior. A sluggish slope gradually approaching Dulong–Petit limit at high temperature was found at a specific heat capacity. Also, high reflectivity and conductivity were observed at the same state. By analyzing the temperature–pressure diagram, reflectivity, conductivity and specific heat comprehensively at conditions simulating the interior of planets in this work, we found that as the pressure rises, a change in ionization appears; it is supposedly attributed to energetics of bond-breaking in the H2O as it transforms from a bonded molecular fluid to an ionic state. Such molecular dissociation in H2O is associated with the conducting transition because the dissociated hydrogen atoms contribute to electrical properties.

Anti-inflammatory activities of gentiopicroside against iNOS and COX-2 targets

Objective: To isolate high-purity gentiopicroside from the Chinese herbal Gentiana officinalis and investigate its anti-inflammatory activity against iNOS and COX-2 targets.Methods: The purity and structures of gentiopicroside were determined by HPLC, IR, NMR, and MS. The anti-inflammatory effects of gentiopicroside were investigated by in vivo, in vitro, and molecular experiments.Results: In vitro experiment results showed that gentiopicroside inhibited nitric oxide(NO), prostaglandin E2(PGE2), and interleukin-6(IL-6) production in mouse macrophages RAW 264.7 stimulated by lipopolysaccharide. In vivo experiment found that xylene-induced mouse ear swelling was inhibited by gentiopicroside with an inhibition rate of 34.17%. Molecular docking of cyclooxygenase-2(COX-2) and inducible nitric oxide synthase(i NOS) with gentiopicroside showed that hydrogen bonds(H-bonds) were formed between the sugar fragments in gentiopicroside structure with Tyr355, Ser353, Leu352, Ser530,Arg120, and His90 of COX-2, and Glu377, Asp382, Tyr373, Tyr347, Gln263, Asn370, and Gly371 of i NOS.Thus, gentiopicroside had a lower docking score and displayed satisfactory anti-inflammatory activities.Conclusion: These results suggested that the mechanism of anti-inflammatory activity of gentiopicroside was associated with the downregulation of inflammatory cytokines, such as NO, PGE2, and IL-6, and the suppression of iNOS and COX-2. Therefore, gentiopicroside is a potential and selective iNOS and COX-2 inhibitor.