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This study evaluated the application of the bipolar electrocoagulation catheter via a peripheral-to-central (3 + 1) technique, relative to directly pressing only at the center of the bleeding site (direct-stroke), to effect endoscopic hemostasis of acute non-varicose gastrointestinal bleeding (ANVUGIB). Patients (n = 148) with endoscopically diagnosed ANVUGIB were randomly apportioned to receive treatment by 3 + 1 (n = 78) or direct-stroke (n = 70) application of the bipolar electrocoagulation catheter. The 3 + 1 strategy required pressing at3 narrowly restricted sites equidistant peripheral and center to the site of bleeding. The rates of initial success, hemostasis time, and number of compressions were compared according to intention-to-treat (ITT) or per protocol (PP). The ITT (PP) rate of initial hemostatic success in patients receiving the 3 + 1 catheter was 91.02% (95.9%); and for the direct-stroke group was 71.42% (76.9%). For Forrest IIa lesions specifically, these rates were respectively 91.70% (97.1%) and 63.9% (67.6%). The ITT (PP) hemostasis times of the 3 + 1 and direct-stroke groups were 10.96 ± 3.28 (10.65 ± 2.90) and 14.27 ± 6.58 (14.12 ± 6.67) min; and the number of compressions numbered 5.73 ± 1.98 (5.42 ± 1.46) and 6.47 ± 2.82 (6.16 ± 2.47). During thermocoagulation treatment of ANVUGIB via bipolar electrocoagulation catheter, the 3 + 1 strategy showed a significantly higher rate of successful initial hemostasis relative to the direct-stroke technique, and shorter hemostasis time, with no increase in total procedural steps.

In this study, an electrical heat-assisted method was adopted to drill a small hole (diameter of 1–3 mm) in hard-to-cut materials, namely, 1Cr18Ni9Ti stainless steel and ZGMn13 high-manganese steel. The flank wear of the twist bit and the surface quality of the small hole were investigated. The relationships among the flank wear, feeding, heating current, and cutting speed were analyzed quantitatively. Flank wear of twist drill directly affected the service life of the drill used in electric hot drilling. The dynamic effects of heating current, cutting speed, and feed rate on the surface roughness and machining hardening of the hole-wall are also discussed. Experimental data indicated that the surface roughness after electric hot drilling can also be obtained by coarse grinding and the surface hardness of the hole-wall had no obvious change. These findings showed that electric hot drilling has irreplaceable advantages in improving the service life of the drill bit and surface quality of the hole-wall.