• 한국수소및신에너지학회논문집
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• 제26권3호
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• pp.287-293
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• 2015

The current study has investigated the effects of biodiesel blended with gasoline on the spray characteristics in a Constant Volume Combustion Chamber (CVCC). With the concentration of 5, 10, 15 and 20% by volume, biodiesel was blended with commercial gasoline and performed on the macroscopic visualization test. Pure gasoline and biodiesel were also tested as the reference. The shadowgraph technique was conducted in the constant volume chamber. The spray images were recorded by a high speed video camera with frame speed 10,000 frame per second. Fuel injection was set at 800, 1000 and 1,350 bar with the simulated speed 1,500 and 2,000 rpm. The back pressure was controlled at 20 bar. The spray angle and penetration tip were measured and analyzed by using the image processing. At the high injection pressure, the spray penetration length with the simulated speed 1,500 rpm showed that B100 was lower than GB00-20 whereas the spray penetration length with the simulated speed 2,000 rpm exhibited that GB blends and B100 were insignificantly different. Due to biodiesel concentration, its effects on spray angles were observed throughout injection periods (T1, T2 and T3). At the simulated speed 1,500 rpm, the spray angle of GB blends and B100 presented the same pattern following injection timing. In addition, when the simulated speed increased to 2,000 rpm the different spray angle of all blends disappeared at main injection (T3).

• Journal of Veterinary Science
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• 제19권6호
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• pp.808-816
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• 2018

Bacterial biofilms have been demonstrated to be closely related to clinical infections and contribute to drug resistance. Berberine, which is the main component of Coptis chinensis, has been reported to have efficient antibacterial activity. This study aimed to investigate the potential effect of a combination of berberine with ciprofloxacin (CIP) to inhibit Salmonella biofilm formation and its effect on expressions of related genes (rpoE, luxS, and ompR). The fractional inhibitory concentration (FIC) index of the combination of berberine with CIP is 0.75 showing a synergistic antibacterial effect. The biofilm's adhesion rate and growth curve showed that the multi-resistant Salmonella strain had the potential to form a biofilm relative to that of strain CVCC528, and the antibiofilm effects were in a dose-dependent manner. Biofilm microstructures were rarely observed at $1/2{\times}MIC/FIC$ concentrations (MIC, minimal inhibition concentration), and the combination had a stronger antibiofilm effect than each of the antimicrobial agents used alone at $1/4{\times}FIC$ concentration. LuxS, rpoE, and ompR mRNA expressions were significantly repressed (p< 0.01) at $1/2{\times}MIC/FIC$ concentrations, and the berberine and CIP combination repressed mRNA expressions more strongly at the $1/4{\times}FIC$ concentration. The results indicate that the combination of berberine and CIP has a synergistic effect and is effective in inhibiting Salmonella biofilm formation via repression of luxS, rpoE, and ompR mRNA expressions.