Although the age-standardized incidence of gastric cancer has decreased in Korea, it remains the second most common type of cancer. The purpose of this study was to analyze the phospholipid fatty acid compositions of gastric mucosa in gastric cancer. Cancerous mucosa and noncancerous mucosa adjacent to cancerous tissues were obtained from 29 patients who had undergone gastrectomy for gastric adenocarcinoma. Phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidylserine (PS) were separated from phospholipids by thin-layer chromatography, and fatty acids were analyzed by gas chromatography. In cancerous mucosa, saturated fatty acids of total phospholipids and stearic acid of PE and PC contents as well as total phospholipids were significantly more abundant than in noncancerous tissues. The ratios of ω6 fatty acid products to linoleic acid of PC, PE, PI, and PS contents as well as total phospholipids were significantly higher in cancerous mucosa than in noncancerous mucosa. Arachidonic acid levels of PE and PI were significantly higher, but the PC level was lower in cancerous mucosa. These results suggest that the characteristic differences in fatty acid compositions of phospholipids and their subfractions shown in gastric cancerous mucosa may be affected by changes in lipid metabolism in gastric carcinogenesis. Further studies on structural and functional changes in phospholipids related to gastric carcinogenesis will be needed.

A robust position-sensing system is proposed in this paper for ubiquitous mobile robots which move indoor as well as outdoor. The Differential GPS (DGPS) which has position estimation error of less than 5 m is a general solution when the mobile robots are moving outdoor, while an active beacon system (ABS) with embedded ultrasonic sensors is selected as an indoor positioning system. The switching from the outdoor to indoor or vice versa causes unstable measurements on account of the reference and algorithm changes. To minimize the switching time in the position estimation and to stabilize the measurement, a robust position-sensing system is proposed. In the system, to minimize the switching delay, the door positions are stored and updated in a database. The reliability and accuracy of the robust positioning system based on DGPS and ABS are verified through the real experiments using a mobile robot prepared for this research and demonstrated.