48 research outputs found

    Carolignans from the Aerial Parts of Euphorbia sikkimensis and Their Anti-HIV Activity

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    Seven new carolignans, including two pairs of enantiomers (±)-erythro-7′-methylcarolignan E (1a/1b) and (±)-threo-7′-methylcarolignan E (2a/2b), (+)-threo-carolignan E (3a), (+)-erythro-carolignan E (4a), and (−)-erythro-carolignan Z (5), together with four known lignans (3b, 4b, 6, and 7) and six polyphenols (8–13) were isolated from the aerial parts of Euphorbia sikkimensis. The structures of the new compounds were elucidated by spectroscopic analysis, and their absolute configurations were determined by electronic circular dichroism calculations. Seven of the isolates were examined for anti-HIV effects, and compounds 1a and 1b showed moderate anti-HIV activity with EC50 values of 6.3 and 5.3 μM

    Experimental Study on Water Distribution and Droplet Kinetic Energy Intensity from Non-Circular Nozzles with Different Aspect Ratios

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    (1) Background: In sprinkler irrigation systems, the water distribution and droplet kinetic energy are affected by the shape of the nozzle. In this paper, the effects of working pressure and aspect ratio (L/D) of circular and non-circular nozzles (diamond and ellipse) on water distribution and droplet kinetic energy intensity were investigated; (2) Methods: The hydraulic performance of a PY15 impact sprinkler with circular and non-circular nozzles was assessed under different working pressures, and the droplet diameter, velocity, and kinetic energy intensity were measured by a 2D video disdrometer. Moreover, the coefficient of variation (CV) and form factor (β) were introduced to represent the water distribution and droplet characteristics; (3) Results: The results revealed that, under the same working pressure, the CV of the diamond nozzle was the smallest compared with that of the circular and elliptical nozzles, reflecting a more uniform water distribution. The uniformity of water distribution was the best when the L/D of the elliptical nozzle was the smallest. In general, the larger the outlet diameter, the larger the wetted radius and water application rate. In addition, the smaller the L/D, the smaller the peak water distribution value and the radial increase of the kinetic energy intensity of a single nozzle. The maximum droplet kinetic energy per unit volume of the elliptical nozzle was the smallest compared with that of the circular and diamond nozzles. The circular nozzle at 200 kPa and the diamond and elliptical nozzles at 100 kPa obtained the highest uniformity coefficients of combined kinetic energy intensity distribution, which were 55.93% (circular), 67.59% (diamond), and 57.78% (elliptical) when the combination spacings were 1.0 R, 1.1 R and 1.2 R, and 1.0 R, respectively. Finally, the fitting function of unit volume droplet kinetic energy, distance from the nozzle, L/D, and working pressure of non-circular nozzles was established, and a fitting coefficient of 0.92 was obtained, indicating that the fitting equation was accurate; (4) Conclusions: At low working pressures, the elliptic and diamond nozzles showed better water distributions than the circular nozzle. The distal average droplet diameters of the sprinkler with non-circular nozzles were found to be smaller than those produced by the circular nozzle

    Experimental Study on Water Distribution and Droplet Kinetic Energy Intensity from Non-Circular Nozzles with Different Aspect Ratios

    No full text
    (1) Background: In sprinkler irrigation systems, the water distribution and droplet kinetic energy are affected by the shape of the nozzle. In this paper, the effects of working pressure and aspect ratio (L/D) of circular and non-circular nozzles (diamond and ellipse) on water distribution and droplet kinetic energy intensity were investigated; (2) Methods: The hydraulic performance of a PY15 impact sprinkler with circular and non-circular nozzles was assessed under different working pressures, and the droplet diameter, velocity, and kinetic energy intensity were measured by a 2D video disdrometer. Moreover, the coefficient of variation (CV) and form factor (β) were introduced to represent the water distribution and droplet characteristics; (3) Results: The results revealed that, under the same working pressure, the CV of the diamond nozzle was the smallest compared with that of the circular and elliptical nozzles, reflecting a more uniform water distribution. The uniformity of water distribution was the best when the L/D of the elliptical nozzle was the smallest. In general, the larger the outlet diameter, the larger the wetted radius and water application rate. In addition, the smaller the L/D, the smaller the peak water distribution value and the radial increase of the kinetic energy intensity of a single nozzle. The maximum droplet kinetic energy per unit volume of the elliptical nozzle was the smallest compared with that of the circular and diamond nozzles. The circular nozzle at 200 kPa and the diamond and elliptical nozzles at 100 kPa obtained the highest uniformity coefficients of combined kinetic energy intensity distribution, which were 55.93% (circular), 67.59% (diamond), and 57.78% (elliptical) when the combination spacings were 1.0 R, 1.1 R and 1.2 R, and 1.0 R, respectively. Finally, the fitting function of unit volume droplet kinetic energy, distance from the nozzle, L/D, and working pressure of non-circular nozzles was established, and a fitting coefficient of 0.92 was obtained, indicating that the fitting equation was accurate; (4) Conclusions: At low working pressures, the elliptic and diamond nozzles showed better water distributions than the circular nozzle. The distal average droplet diameters of the sprinkler with non-circular nozzles were found to be smaller than those produced by the circular nozzle

    A Meta-Analysis of the Efficacy of Interferon Monotherapy or Combined with Different Nucleos(t)ide Analogues for Chronic Hepatitis B

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    Background: The aim of the present study was to compare the efficacy of interferon (IFN) with or without different nucleos(t)ide analogues (NAs). Methods: The PubMed, Wan Fang and CNKI databases were searched to identify relevant trials up to May 2015. Meta-analysis was performed with Review Manager 5.0. The stability and reliability were evaluated by publication bias tests. Results: Fifty-six studies fulfilled the criteria for the meta-analysis. Compared with IFN monotherapy, combination therapy were superior in HBV DNA undetectable rate (Risk Ratio (RR) = 1.55, 95% confidence interval (CI): 1.44–1.66, p < 0.00001), HBeAg and HBsAg loss rate (RR = 1.38, 95% CI: 1.22–1.56, p < 0.00001; RR = 1.69, 95% CI: 1.03–2.78, p = 0.04, respectively) at the end of week 48 treatment. Sub-analysis showed the RRs of virological response for entecavir (ETV), adefovir (ADV), and lamivudine (LAM) were 1.64, 1.61 and 1.52, respectively; RRs of HBeAg loss rate were 1.34, 1.71 and 1.34, respectively. However, at the end of follow-up, IFN plus NAs therapy was better than IFN monotherapy only in terms of HBV DNA undetectable rate (p = 0.0007). Conclusions: Combination therapy was better than IFN monotherapy in virological and serological responses at the end of treatment. After follow-up, only HBV DNA undetectable rate was superior for combination therapy

    Metformin’s Effects on Apoptosis of Esophageal Carcinoma Cells and Normal Esophageal Epithelial Cells: An In Vitro Comparative Study

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    The effect of metformin on human esophageal normal and carcinoma cells remains poorly understood. We aim to investigate the different antiproliferation effects and underlying distinct molecular mechanisms between these two types of cells. Human esophageal squamous cell carcinoma cell line, EC109, and normal esophageal epithelial cell line, HEEC, were used in the experiment. The cell survival rate was determined by cell counting kit-8 (CCK-8). Cell apoptosis was analyzed by flow cytometry. The mRNA and protein levels of signal transducer and activator of transcription 3 (Stat3) were detected by real-time quantitative PCR and western blot. Interleukin-6 (IL-6) was added to activate Stat3. The level of intracellular reactive oxygen species (ROS) was assessed by a DCFH-DA fluorescent probe. Metformin had more significant inhibitory effects on cell proliferation in EC109 cells than HEECs. Metformin induced apoptosis of EC109 cells in a dose-dependent manner instead of HEECs. The expression of Stat3 in both mRNA and protein levels was higher in EC109 cells than HEECs. Further study revealed that metformin may attenuate the phosphorylation of the Stat3 and the Bcl-2 expression, which was restored by IL-6 partly in EC109 cells but not HEECs. On the contrary, metformin increased the level of ROS in both the cell lines, but this intracellular ROS variation had no effect on apoptosis. Metformin has different functional roles on the apoptosis in esophageal carcinoma cells and normal esophageal cells. Therefore, the Stat3/Bcl-2 pathway-mediated apoptosis underlies the cell-type-specific drug sensitivity, suggesting metformin possesses a therapeutic activity and selectivity on esophageal cancer
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