目的:探讨超声引导下肾上盏和肾中盏穿刺路径在经皮肾镜取石术(PCNL)中的临床效果。方法:回顾性分析2022年5月—2023年10月于宜昌市中心人民医院行PCNL的220例上尿路结石患者的临床资料,根据穿刺路径分为两组,经肾上盏穿刺为观察组(n=10...目的:探讨超声引导下肾上盏和肾中盏穿刺路径在经皮肾镜取石术(PCNL)中的临床效果。方法:回顾性分析2022年5月—2023年10月于宜昌市中心人民医院行PCNL的220例上尿路结石患者的临床资料,根据穿刺路径分为两组,经肾上盏穿刺为观察组(n=108),经肾中盏穿刺为对照组(n=112)。对比两组患者的治疗效果及手术并发症。结果:观察组患者手术时间(46.42±9.73 min vs 69.13±15.78 min)、住院时间(5.13±1.20天vs 6.29±1.53天)均明显低于对照组(均P<0.05),观察组患者一期结石清除率(82.41%vs 71.43%)显著高于对照组(P<0.05),两组患者术后血红蛋白下降量及肌酐值无明显差异(均P>0.05)。两组患者术后并发症总发生率无明显差异(P>0.05)。结论:超声引导下经肾上盏穿刺路径行PCNL可缩短手术时间及住院时间,提高一期结石清除率,临床效果确切,安全有效。展开更多
For the safety of railroad operations,sand barriers are utilized to mitigate wind-sand disaster effects.These disasters,characterized by multi-directional wind patterns,result in diverse angles among the barriers.In t...For the safety of railroad operations,sand barriers are utilized to mitigate wind-sand disaster effects.These disasters,characterized by multi-directional wind patterns,result in diverse angles among the barriers.In this study,using numerical simulations,we examined the behavior of High Density Polyethylene(HDPE)sheet sand barriers under different wind angles,focusing on flow field distribution,windproof efficiency,and sedimentation erosion dynamics.This study discovered that at a steady wind speed,airflow velocity varies as the angle between the airflow and the HDPE barrier changes.Specifically,a 90°angle results in the widest low-speed airflow area on the barrier’s downwind side.If the airflow is not perpendicular to the barrier,it prompts a lateral airflow movement which decreases as the angle expands.The windproof efficiency correlates directly with this angle but inversely with the wind’s speed.Notably,with a wind angle of 90°,wind speed drops by 81%.The minimum wind speed is found at 5.1H(the sand barrier height)on the barrier’s downwind side.As the angle grows,the barrier’s windproof efficiency improves,extending its protective reach.Sedimentation is most prominent on the barrier’s downwind side,as the wind angle shifts from 30°to 90°,the sand sedimentation area on the barrier’s downwind side enlarges by 14.8H.As the angle grows,sedimentation intensifies,eventually overtakes the forward erosion and enlarges the sedimentation area.展开更多
Wind and sand hazards are serious in the Milan Gobi area of the Xinjiang section of the Korla Railway. In order to ensure the safe operation of railroads, there is a need for wind and sand protection in heavily sandy ...Wind and sand hazards are serious in the Milan Gobi area of the Xinjiang section of the Korla Railway. In order to ensure the safe operation of railroads, there is a need for wind and sand protection in heavily sandy areas. The wind and sand flow in the region is notably bi-directional. To shield railroads from sand, a unique sand fence made of folded linear high-density polyethylene(HDPE) is used, aligning with the principle that the dominant wind direction is perpendicular to the fence. This study employed field observations and numerical simulations to investigate the effectiveness of these HDPE sand fences in altering flow field distribution and offering protection. It also explored how these fences affect the deposition and erosion of sand particles. Findings revealed a significant reduction in wind speed near the fence corner;the minimum horizontal wind speed on the leeward side of the first sand fence(LSF) decreased dramatically from 3 m/s to 0.64 m/s. The vortex area on the LSF markedly impacted horizontal wind speeds. Within the LSF, sand deposition was a primary occurrence. As wind speeds increased, the deposition zone shrank, whereas the positive erosion zone expanded. Close to the folded corners of the HDPE sand fence, there was a notable shift from the positive erosion zone to a deposition zone. Field tests and numerical simulations confirmed the high windproof efficiency(WE) and sand resistance efficiency(SE) in the HDPE sand fence. Folded linear HDPE sheet sand fence can effectively slow down the incoming flow and reduce the sand content, thus achieving good wind and sand protection. This study provides essential theoretical guidance for the design and improvement of wind and sand protection systems in railroad engineering.展开更多
文摘目的:探讨超声引导下肾上盏和肾中盏穿刺路径在经皮肾镜取石术(PCNL)中的临床效果。方法:回顾性分析2022年5月—2023年10月于宜昌市中心人民医院行PCNL的220例上尿路结石患者的临床资料,根据穿刺路径分为两组,经肾上盏穿刺为观察组(n=108),经肾中盏穿刺为对照组(n=112)。对比两组患者的治疗效果及手术并发症。结果:观察组患者手术时间(46.42±9.73 min vs 69.13±15.78 min)、住院时间(5.13±1.20天vs 6.29±1.53天)均明显低于对照组(均P<0.05),观察组患者一期结石清除率(82.41%vs 71.43%)显著高于对照组(P<0.05),两组患者术后血红蛋白下降量及肌酐值无明显差异(均P>0.05)。两组患者术后并发症总发生率无明显差异(P>0.05)。结论:超声引导下经肾上盏穿刺路径行PCNL可缩短手术时间及住院时间,提高一期结石清除率,临床效果确切,安全有效。
基金financially supported by the Natural Science Foundation of Gansu Province,China(22JR5RA050,20JR10RA231)the fellowship of the China Postdoctoral Science Foundation(2021M703466)the Basic Research Innovation Group Project of Gansu Province,China(21JR7RA347).
文摘For the safety of railroad operations,sand barriers are utilized to mitigate wind-sand disaster effects.These disasters,characterized by multi-directional wind patterns,result in diverse angles among the barriers.In this study,using numerical simulations,we examined the behavior of High Density Polyethylene(HDPE)sheet sand barriers under different wind angles,focusing on flow field distribution,windproof efficiency,and sedimentation erosion dynamics.This study discovered that at a steady wind speed,airflow velocity varies as the angle between the airflow and the HDPE barrier changes.Specifically,a 90°angle results in the widest low-speed airflow area on the barrier’s downwind side.If the airflow is not perpendicular to the barrier,it prompts a lateral airflow movement which decreases as the angle expands.The windproof efficiency correlates directly with this angle but inversely with the wind’s speed.Notably,with a wind angle of 90°,wind speed drops by 81%.The minimum wind speed is found at 5.1H(the sand barrier height)on the barrier’s downwind side.As the angle grows,the barrier’s windproof efficiency improves,extending its protective reach.Sedimentation is most prominent on the barrier’s downwind side,as the wind angle shifts from 30°to 90°,the sand sedimentation area on the barrier’s downwind side enlarges by 14.8H.As the angle grows,sedimentation intensifies,eventually overtakes the forward erosion and enlarges the sedimentation area.
基金financially supported by the Chang Jiang Scholar and Innovation Team Development Plan of China (IRT_15R29)the Basic Research Innovation Group Project of Gansu Province, China (21JR7RA347)the Natural Science Foundation of Gansu Province, China (20JR10RA231)。
文摘Wind and sand hazards are serious in the Milan Gobi area of the Xinjiang section of the Korla Railway. In order to ensure the safe operation of railroads, there is a need for wind and sand protection in heavily sandy areas. The wind and sand flow in the region is notably bi-directional. To shield railroads from sand, a unique sand fence made of folded linear high-density polyethylene(HDPE) is used, aligning with the principle that the dominant wind direction is perpendicular to the fence. This study employed field observations and numerical simulations to investigate the effectiveness of these HDPE sand fences in altering flow field distribution and offering protection. It also explored how these fences affect the deposition and erosion of sand particles. Findings revealed a significant reduction in wind speed near the fence corner;the minimum horizontal wind speed on the leeward side of the first sand fence(LSF) decreased dramatically from 3 m/s to 0.64 m/s. The vortex area on the LSF markedly impacted horizontal wind speeds. Within the LSF, sand deposition was a primary occurrence. As wind speeds increased, the deposition zone shrank, whereas the positive erosion zone expanded. Close to the folded corners of the HDPE sand fence, there was a notable shift from the positive erosion zone to a deposition zone. Field tests and numerical simulations confirmed the high windproof efficiency(WE) and sand resistance efficiency(SE) in the HDPE sand fence. Folded linear HDPE sheet sand fence can effectively slow down the incoming flow and reduce the sand content, thus achieving good wind and sand protection. This study provides essential theoretical guidance for the design and improvement of wind and sand protection systems in railroad engineering.
