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The aerodynamic properties of a pantograph that is under consideration for application on Korean high-speed trains are experimentally investigated. The selected experimental models were one-quarter scale pantographs (a double-arm pantograph, single-arm pantograph and a periscope pantograph) with either a rectangular panhead or a panhead with an optimized streamlined shape. To increase the performance and the robustness of the pantograph, the drag coefficient and the fluctuation of the lift coefficient along the angle of attack are simultaneously minimized. In order to confirm the aerodynamic enhancement of the pantograph due to the optimized panhead, the aerodynamic forces are compared with those of a pantograph with a rectangular panhead. To investigate the aerodynamic force distribution of a pantograph, the aerodynamic forces of the lift and drag of the pantograph are measured in wind tunnel tests and analyzed in terms of the pantograph’s components. In addition, wake flows are examined based on variations of the shape of the panhead. [ABSTRACT FROM PUBLISHER]

N-Nicotinoylglycyl-2-(5-fluorouracil-1-yl)-d,l-glycine (NGFG) was synthesized as a colon-specific prodrug of 5-fluorouracil (5-FU) expecting that hydrolysis of nicotinoyl and glycyl moieties by microbial enzymes in the colon will give 2-(5-fluorouracil-1-yl)-d,l-glycine, which releases 5-FU spontaneously. To in vitro-evaluate colon targetability of NGFG, apparent partition coefficient and chemical/biochemical stability of NGFG in the contents or/and tissue of the various segments of the gastrointestinal tract were determined. Low partition coefficient and stability of NGFG in the upper intestinal condition suggested its delivery to the colon in intact form after oral administration. Incubation with rat cecal contents produced 5-FU and its metabolite about 16%. Structural modification to enhance amide hydrolysis, the rate determining step in NGFG bioactivation, is suggested. [ABSTRACT FROM AUTHOR]