Optimization model of number of scheduled freight train formation cars
The determination of the number of formation cars is an important part of making a scheduled freight train plan, and it also has a large influence on the benefits of railway freight transportation. First, the influences that affect the number of formation cars are analyzed. Secondly, taking the maximum freight transport benefits as an objective, and comprehensively considering the primary factors that include service frequency of freight trains, section traction weight, effective length of arrival-departure tracks, and so on, this paper establishes the optimization model of the number of scheduled freight train formation cars. Finally, the solving method for the model is presented, and a case is given to show the solution process. It provides a reference for decision-makers of railway freight transportation.
Study on the Minimum Number of Cars in Fixed-point Departure Mode
There are two kinds of departure mode of freight train in marshalling station, which are fixed-point departure mode and fixed-consist departure mode. In order to determine the model of minimum number of cars in fixed-point departure mode, this paper gives some assumptions on the condition of the departure mode, studies the operation index about the two departure modes and finds out the basic change principle. Furthermore, the paper puts forward five concepts, which include favorable minimum number of cars, benefit minimum number of cars, cost minimum number of cars, capacity minimum number of cars and model minimum number of cars, and gives the determination method of the variables corresponding to the five concepts. The study shows that the fixed-point departure mode of freight train is adapted better to the condition of smaller vehicle flow and shorter distance of running section.
Protective effect of ginsenoside Re on acute gastric mucosal lesion induced by compound 48/80
The protective effect of ginsenoside Re, isolated from ginseng berry, against acute gastric mucosal lesions was examined in rats with a single intraperitoneal injection of compound 48/80 (C48/80). Ginsenoside Re (20 mg/kg or 100 mg/kg) was orally administered 0.5 h prior to C48/80 treatment. Ginsenoside Re dose-dependently prevented gastric mucosal lesion development 3 h after C48/80 treatment. Increases in the activities of myeloperoxidase (MPO; an index of neutrophil infiltration) and xanthine oxidase (XO) and the content of thiobarbituric acid reactive substances (TBARS; an index of lipid peroxidation) and decreases in the contents of hexosamine (a marker of gastric mucus) and adherent mucus, which occurred in gastric mucosal tissues after C48/80 treatment, were significantly attenuated by ginsenoside Re. The elevation of Bax expression and the decrease in Bcl2 expression after C48/80 treatment were also attenuated by ginsenoside Re. Ginsenoside Re significantly attenuated all these changes 3 h after C48/80 treatment. These results indicate that orally administered ginsenoside Re protects against C48/80-induced acute gastric mucosal lesions in rats, possibly through its stimulatory action on gastric mucus synthesis and secretion, its inhibitory action on neutrophil infiltration, and enhanced lipid peroxidation in the gastric mucosal tissue.