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To assess the effectiveness and safety of irradiation stent insertion for patients with distal biliary obstruction (DBO) secondary to primary common biliary cancer. Eighty-two consecutive patients with DBO secondary to primary common biliary cancer were treated via either normal (n = 45) or irradiation stenting (n = 37) between January 2013 and December 2019. The instant and long-term outcomes were compared. Technical success rates of normal and irradiation stenting were both 100%. Clinical success rates of normal and irradiation stenting were 91.1 and 100%, respectively (p =.179). Stent reobstruction was observed in 13 and 7 patients in the normal and irradiation stenting groups, respectively (p =.295). The median stent patency was 162 and 225 days in the normal and irradiation stenting groups, respectively (p <.001). The median survival was 178 and 250 days in the normal and irradiation stenting groups, respectively (p <.001). Cholangitis was, respectively, observed in 8 and 12 patients in normal and irradiation stenting groups (p =.124). Irradiation stenting is effective and safe for patients with DBO secondary to primary common biliary cancer and can prolong stent patency and survival. [ABSTRACT FROM AUTHOR]

With the rapid development of dense apple tree plantings with the dwarf rootstock cultivation method, determining accumulation and distribution characteristics of soil mineral nitrogen in densely planted orchards with dwarf rootstock is important to enable scientific fertilization of apple orchards. We investigated densely planted apple orchards with dwarf rootstocks and different plant ages (6 a, 9 a, and 12 a). We collected soil samples under trees, between trees, between rows, and at the midpoints between the trees and rows, and examined the accumulation and distribution characteristics of nitrate, ammonium, and mineral nitrogen. The cumulative amount of nitrate in the 0-300 cm soil layer increased with plant age. The difference between orchards with different plant ages was significant and showed the trend 6 a<9 a<12 a. The cumulative amount of nitrate increased from 1729 kg·hm -2 to 3771 kg·hm -2 with increasing plant age. The ammonium content was low for orchards of all plant ages and had little effect on the accumulation and spatial distribution of mineral nitrogen. There were two accumulation peaks of nitrate nitrogen in the vertical direction. The depth of soil layer where the second accumulation peak was located decreased from 180 cm to 220 cm with increasing plant age. In the horizontal direction, soil nitrate nitrogen content between rows increased from 27 mg·kg -1 to 138 mg·kg -1 with increasing plant age, representing a more than 400% increase. The difference between orchards with different plant ages was significant. In summary, excessive usage of nitrogen fertilizer and serious leaching of nitrate were problematic in all orchards with different ages. Less nitrogen fertilizer should be applied, and anti-seepage measures should be used at the fertilization location to prevent the leaching of nitrate to deep layers.