AIM:To evaluate the safety and efficacy of CO2 insufflation compared with air insufflation in the endoscopic submucosal excavation(ESE) of gastrointestinal stromal tumors.METHODS:Sixty patients were randomized to unde...AIM:To evaluate the safety and efficacy of CO2 insufflation compared with air insufflation in the endoscopic submucosal excavation(ESE) of gastrointestinal stromal tumors.METHODS:Sixty patients were randomized to undergo endoscopic submucosal excavation,with the CO2 group(n = 30) and the air group(n = 30) undergoingCO2 insufflation and air insufflation in the ESE,respectively.The end-tidal CO2 level(pETCO2) was observed at 4 time points:at the beginning of ESE,at total removal of the tumors,at completed wound management,and 10 min after ESE.Additionally,the patients' experience of pain at 1,3,6 and 24 h after the examination was registered using a visual analog scale(VAS).RESULTS:Both the CO2 group and air group were similar in mean age,sex,body mass index(all P > 0.05).There were no significant differences in PetCO2 values before and after the procedure(P > 0.05).However,the pain scores after the ESE at different time points in the CO2 group decreased significantly compared with the air group(1 h:21.2 ± 3.4 vs 61.5 ± 1.7;3 h:8.5 ± 0.7 vs 42.9 ± 1.3;6 h:4.4 ± 1.6 vs 27.6 ± 1.2;24 h:2.3 ± 0.4 vs 21.4 ± 0.7,P < 0.05).Meanwhile,the percentage of VAS scores of 0 in the CO2 group after 1,3,6 and 24 h was significantly higher than that in the air group(60.7 ± 1.4 vs 18.9 ± 1.5,81.5 ± 2.3 vs 20.6 ± 1.2,89.2 ± 0.7 vs 36.8 ± 0.9,91.3 ± 0.8 vs 63.8 ± 1.3,respectively,P < 0.05).Moreover,the condition of the CO2 group was better than that of the air group with respect to anal exsufflation.CONCLUSION:Insufflation of CO2 in the ESE of gastrointestinal stromal tumors will not cause CO2 retention and it may significantly reduce the level of pain,thus it is safe and effective.展开更多
As a result of a sustained drought in the Southwestern United States, and in order to maintain existing water capacity in the Las Vegas Valley, the Southern Nevada Water Authority constructed a new deep- water intake ...As a result of a sustained drought in the Southwestern United States, and in order to maintain existing water capacity in the Las Vegas Valley, the Southern Nevada Water Authority constructed a new deep- water intake （Intake No. 3） located in Lake Mead. The project included a 185 m deep shaft, 4.7 km tunnel under very difficult geological conditions, and marine works for a submerged intake. This paper presents the experience that was gained during the design and construction and the innovative solutions that were developed to handle the difficult conditions that were encountered during tunneling with a dual- mode slurry tunnel-boring machine （TBM） in up to 15 bar （l bar = l0s Pa） pressure. Specific attention is given to the main challenges that were overcome during the TBM excavation, which included the mode of operation, face support pressures, pre-excavation grouting, and maintenance; to the construction of the intake, which involved deep underwater shaft excavation with blasting using shaped charges; to the construction of the innovative over 1200 t concrete-and-steel intake structure; to the placement of the intake structure in the underwater shaft; and to the docking and connection to an intake tunnel excavated by hybrid TBM.展开更多
To realize a stable addition of foaming agent used for foam technology, a new adding method using the jet cavitation was introduced, and its performance was investigated experimentally under different operating condit...To realize a stable addition of foaming agent used for foam technology, a new adding method using the jet cavitation was introduced, and its performance was investigated experimentally under different operating conditions. Experimental results show that the bubble region in the jet device has a constant vapor pressure, which creates a good condition for liquid absorption, while it shrinks with increasing outlet pressure. The liquid absorption amount keeps unchanged when the outlet pressure is lower than a critical value. The critical outlet pressure increases by 40% with decreasing cavitation absorption amount, which is especially suitable for mini-flow quantitative addition of foaming agent used for foam dust suppression. Its effectiveness on suppressing mine dust was evaluated in a heading face of underground coal mines. Field application indicates that the reliable and simple foaming system adopting the new adding method makes a marked dust suppression effect. The working environment of heading face is significantly improved, ensuring the safe tunneling and personal security.展开更多
Recent years, underground mining method is becoming popular because of its potentially high productivity and efficiency. In this method, a mining machinery; load haul dump(LHD), is used as both an excavator and a tran...Recent years, underground mining method is becoming popular because of its potentially high productivity and efficiency. In this method, a mining machinery; load haul dump(LHD), is used as both an excavator and a transporter of ore. This paper proposes a distributed system that realizes the excavation and transport functions with separated vehicles, an excavator and a transporter. In addition, this research proposes a mining map and configurations suitable for the proposed distributed system. To evaluate the productivity of the proposed system, a simulation environment has been developed. Analysis using the simulator reveals what performance factors of the excavator and the transporter have large impacts on the productivity. Simulation results also demonstrate the difference of potential between LHD system and the distributed system that can be explained based on their functions allocation.展开更多
基金Supported by Grants from Project of Science and Technology Commission of Shanghai Municipality,No. 10441901702Nano-specific Project of Science and Technology Commission of Shanghai Municipality,No. 11nm0503700Shang-hai Key Laboratory of Pediatric Digestion and Nutrition,No. 11DZ2260500
文摘AIM:To evaluate the safety and efficacy of CO2 insufflation compared with air insufflation in the endoscopic submucosal excavation(ESE) of gastrointestinal stromal tumors.METHODS:Sixty patients were randomized to undergo endoscopic submucosal excavation,with the CO2 group(n = 30) and the air group(n = 30) undergoingCO2 insufflation and air insufflation in the ESE,respectively.The end-tidal CO2 level(pETCO2) was observed at 4 time points:at the beginning of ESE,at total removal of the tumors,at completed wound management,and 10 min after ESE.Additionally,the patients' experience of pain at 1,3,6 and 24 h after the examination was registered using a visual analog scale(VAS).RESULTS:Both the CO2 group and air group were similar in mean age,sex,body mass index(all P > 0.05).There were no significant differences in PetCO2 values before and after the procedure(P > 0.05).However,the pain scores after the ESE at different time points in the CO2 group decreased significantly compared with the air group(1 h:21.2 ± 3.4 vs 61.5 ± 1.7;3 h:8.5 ± 0.7 vs 42.9 ± 1.3;6 h:4.4 ± 1.6 vs 27.6 ± 1.2;24 h:2.3 ± 0.4 vs 21.4 ± 0.7,P < 0.05).Meanwhile,the percentage of VAS scores of 0 in the CO2 group after 1,3,6 and 24 h was significantly higher than that in the air group(60.7 ± 1.4 vs 18.9 ± 1.5,81.5 ± 2.3 vs 20.6 ± 1.2,89.2 ± 0.7 vs 36.8 ± 0.9,91.3 ± 0.8 vs 63.8 ± 1.3,respectively,P < 0.05).Moreover,the condition of the CO2 group was better than that of the air group with respect to anal exsufflation.CONCLUSION:Insufflation of CO2 in the ESE of gastrointestinal stromal tumors will not cause CO2 retention and it may significantly reduce the level of pain,thus it is safe and effective.
文摘As a result of a sustained drought in the Southwestern United States, and in order to maintain existing water capacity in the Las Vegas Valley, the Southern Nevada Water Authority constructed a new deep- water intake （Intake No. 3） located in Lake Mead. The project included a 185 m deep shaft, 4.7 km tunnel under very difficult geological conditions, and marine works for a submerged intake. This paper presents the experience that was gained during the design and construction and the innovative solutions that were developed to handle the difficult conditions that were encountered during tunneling with a dual- mode slurry tunnel-boring machine （TBM） in up to 15 bar （l bar = l0s Pa） pressure. Specific attention is given to the main challenges that were overcome during the TBM excavation, which included the mode of operation, face support pressures, pre-excavation grouting, and maintenance; to the construction of the intake, which involved deep underwater shaft excavation with blasting using shaped charges; to the construction of the innovative over 1200 t concrete-and-steel intake structure; to the placement of the intake structure in the underwater shaft; and to the docking and connection to an intake tunnel excavated by hybrid TBM.
基金Project(51474216)supported by the National Natural Science Foundation of ChinaProject supported by the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions,ChinaProject(2012DXS02)supported by the Fundamental Research Funds for the Central Universities,China
文摘To realize a stable addition of foaming agent used for foam technology, a new adding method using the jet cavitation was introduced, and its performance was investigated experimentally under different operating conditions. Experimental results show that the bubble region in the jet device has a constant vapor pressure, which creates a good condition for liquid absorption, while it shrinks with increasing outlet pressure. The liquid absorption amount keeps unchanged when the outlet pressure is lower than a critical value. The critical outlet pressure increases by 40% with decreasing cavitation absorption amount, which is especially suitable for mini-flow quantitative addition of foaming agent used for foam dust suppression. Its effectiveness on suppressing mine dust was evaluated in a heading face of underground coal mines. Field application indicates that the reliable and simple foaming system adopting the new adding method makes a marked dust suppression effect. The working environment of heading face is significantly improved, ensuring the safe tunneling and personal security.
文摘Recent years, underground mining method is becoming popular because of its potentially high productivity and efficiency. In this method, a mining machinery; load haul dump(LHD), is used as both an excavator and a transporter of ore. This paper proposes a distributed system that realizes the excavation and transport functions with separated vehicles, an excavator and a transporter. In addition, this research proposes a mining map and configurations suitable for the proposed distributed system. To evaluate the productivity of the proposed system, a simulation environment has been developed. Analysis using the simulator reveals what performance factors of the excavator and the transporter have large impacts on the productivity. Simulation results also demonstrate the difference of potential between LHD system and the distributed system that can be explained based on their functions allocation.
