Background:Porphyromonas gingivalis, a major periodontopathic bacterium, is necessary for periodontitis to take place. The lipopolysaccharide (LPS) of P. gingivalis stimulates cytokine secretion in immune cells, and thereby initiates the inflammation related to periodontitis. Macrophages are the important ones of the immune cells that are prominent at inflammatory periodontal sites. Curcumin, a major curcumanoid found in the spice turmeric, exhibits anti-inflammatory properties. The aim of this study was to investigate the anti-inflammatory effect and the mechanism of action of curcumin in macrophages stimulated by P. gingivalis LPS. Methods: RAW264.7 cells pre-treated with various concentrations of curcumin were stimulated by P. gingivalis LPS. TNF-α and IL-1β expressions were separately detected by RT-PCR and ELISA. Next, activation of NF-ĸB-dependent transcription was examined by luciferase assay. Results: Curcumin dose-dependently inhibited TNF-α and IL-1β gene expression and protein synthesis in RAW264.7 cells stimulated with P. gingivalis LPS. P. gingivalis LPS activated NF-ĸB-dependent transcription in RAW264.7 cells, which were down-regulated by pre-treatment with curcumin as well. Conclusion: Our data suggest that curcumin can inhibit P. gingivalis LPS-induced cytokine expression, and that this could be due to the inhibition of the NF-ĸB pathway.

Preciously tuning the surface composition of noble metal nanoparticles with the particle size of only 2 nm or less by alloying with other metals represents a powerful strategy to boost their electrocatalytic selectivity. However, the synthesis of ultrafine nanoalloys and tuning their surface composition remain challenging. In this report, ultrafine CuPd nanoalloys with the particle size of ca. 2 nm are synthesized based on the galvanic replacement reaction between presynthesized Cu nanoparticles and Pd2+ precursors, and the tuning of their surface compositions is also achieved by changing the atom ratios of Cu/Pd. For the electrocatalytic reduction of CO2, Cu5Pd5 nanoalloys show the CO Faradaic efficiency (FE) of 88% at −0.87 V, and the corresponding mass activity reaches 56 A/g that is much higher than those of Cu8Pd2 nanoalloys, Cu3Pd7 nanoalloys and most of previously reported catalysts. Density functional theory uncovers that with the increase of Pd on the surface of the ultrafine CuPd nanoalloys, the adsorbed energy of both of intermediate COOH* and CO* to the Pd sites is strengthened. The Cu5Pd5 nanoalloys with the optimal surface composition better balance the adsorption of COOH* and desorption of CO*, achieving the highest selectivity and activity. The difficult liberation of absorbed CO* on the surface of Cu3Pd7 nanoalloys provides carbon source to favor the production of ethylene, endowing the Cu3Pd7 nanoalloys with the highest selectivity for ethylene among these ultrafine CuPd nanoalloys.

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Rechargeable Mg batteries (RMBs) are advantageous for large-scale energy storage because of the abundant reserves and high safety, but inorganic cathodes suffer from few species, low capacities and sluggish Mg2+...