3,773 research outputs found

    Optical Monitoring of the Seyfert Galaxy NGC 4151 and Possible Periodicities in the Historical Light Curve

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    We report B, V, and R band CCD photometry of the Seyfert galaxy NGC 4151 obtained with the 1.0-m telescope at Weihai Observatory of Shandong University and the 1.56-m telescope at Shanghai Astronomical Observatory from 2005 December to 2013 February. Combining all available data from literature, we have constructed a historical light curve from 1910 to 2013 to study the periodicity of the source using three different methods (the Jurkevich method, the Lomb-Scargle periodogram method and the Discrete Correlation Function method). We find possible periods of P_1=4\pm0.1, P_2=7.5\pm0.3 and P_3=15.9\pm0.3 yr.Comment: 8 pages, 5 figures, Accepted by Research in Astronomy and Astrophysic

    Disodium dihydrogen pyridine-2,3,5,6-tetra­carboxyl­ate trihydrate

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    In the title compound, 2Na+·C9H3NO8 2−·3H2O, the asymmetric unit consists of two Na+ cations, one dihydrogen pyridine-2,3,5,6-tetra­carboxyl­ate dianion (H2pdtc2−) and three water mol­ecules coordinated to the Na+ cations. The configuration of the anion is stabilized by intramolecular O—H⋯O hydrogen bonding between vicinal carboxylate/carboxy groups. The Na+ cations are bridged by the H2pdtc2− dianions, generating layers extending infinitely in sheets parallel to (001), and further pillared by the water mol­ecule linkers to build up a three-dimensional framework

    Effect of Paris polyphylla extract on second-degree burns in rats

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    Purpose: To investigate the healing effect of Paris polyphylla extract (PPE) on second-degree burns in rats.Methods: Male Sprague Dawley (SD) rats, weighing 200 – 220 g, were subjected to deep seconddegree skin burns by electrical scald instrument. The animals were divided into three groups as follows: (1) second-degree burn model (control) group, (2) burn model treated with 1 % silver sulfadiazine (SSD) group, and (3) burn model treated with 120 mg·mL-1 PPE group. On days 3, 7 and 14 following the administration of the drug/extract, wound area and histopathological changes in rat epidermis were evaluated for the three groups. The minimum inhibitory concentration (MIC) of PPE on Staphyloccocus aureus, Pseudomonas aeruginosa and Escherichia coli were also assessed.Results: On day 14, the mean wound area of PPE treatment group (0.21 ± 0.04 cm2) was significantly smaller than that of the control rats (2.78 ± 0.18 cm2, p < 0.01). Histological results indicate that inflammatory cells disappeared and were replaced by new granulation tissue in the group treated with 120 mg·mL-1 PPE by day 14. Compared with SSD group rats, the inflammatory cells and fibroblast and granulation tissues of burnt rats with burns and treated with 120 mg·mL-1 PPE decreased significantly. The antibacterial data revealed that the MIC of PPE against S. aureus, P. aeruginosa and E. coli was 2.35, 8.2 and 4.70 mg·mL-1, respectively.Conclusion: Paris polyphylla is an effective medicinal herb that holds promise for the treatment of second-degree burns.Keywords: Paris polyphylla, Second-degree burns, Wound healing, Antibacterial, Inflammatory cells, Granulation tissues, Silver sulfadiazin
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