The South-to-North Water Diversion Project in China aims to address the imbalanced distribution of water resources between the northern and southern regions,a critical safeguard for sustainable socio-economic and ecol...The South-to-North Water Diversion Project in China aims to address the imbalanced distribution of water resources between the northern and southern regions,a critical safeguard for sustainable socio-economic and ecological development.In this study,we investigated the hydroclimatic evolution of the water source area and its driving mechanisms using the inflow runoff data at Danjiangkou Reservoir from 1954 to 2013,along with multiple gridded hydroclimatic datasets.Based on the correlations between instrumental runoff data and gridded hydroclimatic variables,we used linear regression to extend the long-term runoff record to the period of 1902-2019.Our results indicate that climate changes,dominated by regional wet-dry cycles,have significant impacts on runoff variations,while the influence of human activities remains comparatively limited.Danjiangkou Reservoir can maintain a balanced base flow,even during the operation of the water diversion project.Preliminary synoptic climatology analyses reveal that runoff variations are mainly driven by the El Niño-Southern Oscillation(ENSO)and the Pacific Walker Circulation(PWC),which affect runoff by altering large-scale ocean-to-continent water vapor processes.This study advances the field by integrating multi-source data with analytical techniques,which enhances understanding of long-term runoff changes in the Danjiangkou Reservoir and their climatic drivers,ultimately supporting sustainable water resource management.展开更多
BACKGROUND Colonic anastomotic leakage(AL)remains a feared complication of colorectal surgery.Usually,a defunctioning stoma or a proximal colostomy is performed to reduce the AL rate but cannot completely prevent AL.M...BACKGROUND Colonic anastomotic leakage(AL)remains a feared complication of colorectal surgery.Usually,a defunctioning stoma or a proximal colostomy is performed to reduce the AL rate but cannot completely prevent AL.Moreover,defunctioning colostomy is associated with high morbidity.This study assessed the feasibility of completely preventing colonic AL using total enteric flow diversion without a defunctioning stoma in a pig model of colonic AL.AIM To determine the feasibility of preventing colonic AL via total enteric flow diversion in pigs.METHODS A total of 14 pigs underwent surgery to create colon anaesthesia with severe defects for establishing the AL model.The pigs were then randomized into the control group(n=7),which received no further therapy,and a diversion group(n=7),which underwent placement of a modified ileostomy tube to divert the enteric contents from the colon externally.The general condition,serum Creactive protein level,white blood cell count,5-day incidence of colon AL,and development of abdominal abscesses were evaluated.RESULTS A modified ileostomy tube with a balloon was placed and pressurized to 20 kPa at a distance of 10-20 cm proximal to the ileocecal valve,effectively obstructing the intestine without causing injury and efficiently diverting the enteric contents.In the diversion group,no cases of peritonitis or abscess were observed.In contrast,all pigs in the control group developed either abdominal abscesses or peritonitis.CONCLUSION Instead of ileostomy or colostomy,the total enteric flow diversion technique with the placement of a modified ileostomy tube and balloon in the ileum can effectively or completely prevent colon AL.展开更多
The hydrogen-enriched direct reduction shaft furnace addresses the high CO_(2) emissions associated with the blast furnace process.A discrete element method(DEM)model was introduced to explore how the structure of the...The hydrogen-enriched direct reduction shaft furnace addresses the high CO_(2) emissions associated with the blast furnace process.A discrete element method(DEM)model was introduced to explore how the structure of the diversion cone affects particle descent behavior in a hydrogen-enriched shaft furnace.The results indicated that in the absence of a diversion cone,the descending velocity near the furnace wall zone is significantly lower than that at its center,resulting in a‘V’-shaped burden flow pattern.The discharge velocity has a minor impact on the flow pattern in the shaft furnace.Upon installation of a diversion cone,burden descending velocity becomes more uniform,leading to a‘-’-shaped burden flow pattern.As the bottom of the diversion cone ascends(i.e.,the lower end of the diversion cone is progressively closer to the top),there is an increase in the volume fraction of the dead zone within the shaft furnace.This is particularly evident in the formation of a triangular dead zone at the base of the diversion cone.It is suggested that the lower cone of the bi-conical diversion cone should maintain a sufficient height.展开更多
BACKGROUND Progressive familial intrahepatic cholestasis type 1(PFIC-1)is a genetic cholestatic disease causing end-stage liver disease,which needs liver transplantation(LT).Simultaneous biliary diversion(BD)was recom...BACKGROUND Progressive familial intrahepatic cholestasis type 1(PFIC-1)is a genetic cholestatic disease causing end-stage liver disease,which needs liver transplantation(LT).Simultaneous biliary diversion(BD)was recommended to prevent allograft steatosis after transplantation,while increasing the risk of infection.Here,an attempt was made to perform BD using appendix to prevent bacterial translocation after LT.CASE SUMMARY An 11-month-old boy diagnosed with PFIC-1 received ABO compatible living donor LT due to refractory jaundice and pruritus.His mother donated her left lateral segment with a graft-to-recipient weight ratio of 2.9%.Internal BD was constructed during LT using the appendix by connecting its proximal end with the intrahepatic biliary duct and the distal end with colon.Biliary leakage was suspected on the 5th day after transplantation and exploratory laparotomy indicated biliary leakage at the cutting surface of liver.The liver function returned to normal on the 9th day post-operation and maintained normal during the 15-month follow-up.Cholangiography at 10 months after transplantation confirmed the direct secretion of bile into colon.Computerized tomography scan(4 months and 10 months)and liver biopsy(10 months)indicated no steatosis in the allograft.No complaint of recurrent diarrhea,infection or growth retardation was reported during follow-up.CONCLUSION Internal BD using appendix during LT is effective in preventing allograft steatosis and post-transplant infection in PFIC-1 recipients.展开更多
Multi-stage and multi-cluster fracturing(MMF)is a crucial technology in unconventional oil and gas development,aiming to enhance production by creating extensive fracture networks.However,achieving uniform expansion o...Multi-stage and multi-cluster fracturing(MMF)is a crucial technology in unconventional oil and gas development,aiming to enhance production by creating extensive fracture networks.However,achieving uniform expansion of multi-cluster hydraulic fractures(HFs)in MMF remains a significant challenge.Field practice has shown that the use of temporary plugging and diversion fracturing(TPDF)can promote the balanced expansion of multi-cluster HFs.This study conducted TPDF experiments using a true triaxial fracturing simulation system setting a horizontal well completion with multi-cluster jetting perforations to investigate the equilibrium initiation and extension of multi-cluster fractures.The influence of key parameters,including cluster spacing,fracturing fluid viscosity,differential stress,and fracturing fluid injection rate,on fracture initiation and propagation was systematically examined.The results indicate that while close-spaced multi-cluster fracturing significantly increases the number of HFs,it also leads to uneven extension of HFs in their propagation.In contrast,TPDF demonstrates effectiveness in mitigating uneven HF extension,increasing the number of HFs,and creating a larger stimulated reservoir volume,ultimately leading to improved oil and gas well productivity.Moreover,under conditions of high differential stress,the differential stress within the formation exerts a stronger guiding effect in HFs,which are more closely aligned with the minimum principal stress.Low-viscosity fluids facilitate rapid and extensive fracture propagation within the rock formation.High-volume fluid injection,on the other hand,more comprehensively fills the formation.Therefore,employing lowviscosity and high-volume fracturing is advantageous for the initiation and extension of multi-cluster HFs.展开更多
基金supported by the National Natural Science Foundation of China(NSFC Project No.32061123008)the Innovation Training Programme for Undergraduate Students of Yunnan University(Project No.202301051).
文摘The South-to-North Water Diversion Project in China aims to address the imbalanced distribution of water resources between the northern and southern regions,a critical safeguard for sustainable socio-economic and ecological development.In this study,we investigated the hydroclimatic evolution of the water source area and its driving mechanisms using the inflow runoff data at Danjiangkou Reservoir from 1954 to 2013,along with multiple gridded hydroclimatic datasets.Based on the correlations between instrumental runoff data and gridded hydroclimatic variables,we used linear regression to extend the long-term runoff record to the period of 1902-2019.Our results indicate that climate changes,dominated by regional wet-dry cycles,have significant impacts on runoff variations,while the influence of human activities remains comparatively limited.Danjiangkou Reservoir can maintain a balanced base flow,even during the operation of the water diversion project.Preliminary synoptic climatology analyses reveal that runoff variations are mainly driven by the El Niño-Southern Oscillation(ENSO)and the Pacific Walker Circulation(PWC),which affect runoff by altering large-scale ocean-to-continent water vapor processes.This study advances the field by integrating multi-source data with analytical techniques,which enhances understanding of long-term runoff changes in the Danjiangkou Reservoir and their climatic drivers,ultimately supporting sustainable water resource management.
基金Supported by the Fundamental Research Funds for the Central Universities of Central South University,No.2024XQLH027.
文摘BACKGROUND Colonic anastomotic leakage(AL)remains a feared complication of colorectal surgery.Usually,a defunctioning stoma or a proximal colostomy is performed to reduce the AL rate but cannot completely prevent AL.Moreover,defunctioning colostomy is associated with high morbidity.This study assessed the feasibility of completely preventing colonic AL using total enteric flow diversion without a defunctioning stoma in a pig model of colonic AL.AIM To determine the feasibility of preventing colonic AL via total enteric flow diversion in pigs.METHODS A total of 14 pigs underwent surgery to create colon anaesthesia with severe defects for establishing the AL model.The pigs were then randomized into the control group(n=7),which received no further therapy,and a diversion group(n=7),which underwent placement of a modified ileostomy tube to divert the enteric contents from the colon externally.The general condition,serum Creactive protein level,white blood cell count,5-day incidence of colon AL,and development of abdominal abscesses were evaluated.RESULTS A modified ileostomy tube with a balloon was placed and pressurized to 20 kPa at a distance of 10-20 cm proximal to the ileocecal valve,effectively obstructing the intestine without causing injury and efficiently diverting the enteric contents.In the diversion group,no cases of peritonitis or abscess were observed.In contrast,all pigs in the control group developed either abdominal abscesses or peritonitis.CONCLUSION Instead of ileostomy or colostomy,the total enteric flow diversion technique with the placement of a modified ileostomy tube and balloon in the ileum can effectively or completely prevent colon AL.
基金the National Key R&D Program of China(Nos.2021YFC2902400 and 2021YFC2902401)the project of State Key Laboratory of Intelligent Optimized Manufacturing in Mining&Metallurgy Process(No.BGRIMM-KZSKL-2023-14).
文摘The hydrogen-enriched direct reduction shaft furnace addresses the high CO_(2) emissions associated with the blast furnace process.A discrete element method(DEM)model was introduced to explore how the structure of the diversion cone affects particle descent behavior in a hydrogen-enriched shaft furnace.The results indicated that in the absence of a diversion cone,the descending velocity near the furnace wall zone is significantly lower than that at its center,resulting in a‘V’-shaped burden flow pattern.The discharge velocity has a minor impact on the flow pattern in the shaft furnace.Upon installation of a diversion cone,burden descending velocity becomes more uniform,leading to a‘-’-shaped burden flow pattern.As the bottom of the diversion cone ascends(i.e.,the lower end of the diversion cone is progressively closer to the top),there is an increase in the volume fraction of the dead zone within the shaft furnace.This is particularly evident in the formation of a triangular dead zone at the base of the diversion cone.It is suggested that the lower cone of the bi-conical diversion cone should maintain a sufficient height.
基金Supported by the National Natural Science Foundation of China,No.82471804.
文摘BACKGROUND Progressive familial intrahepatic cholestasis type 1(PFIC-1)is a genetic cholestatic disease causing end-stage liver disease,which needs liver transplantation(LT).Simultaneous biliary diversion(BD)was recommended to prevent allograft steatosis after transplantation,while increasing the risk of infection.Here,an attempt was made to perform BD using appendix to prevent bacterial translocation after LT.CASE SUMMARY An 11-month-old boy diagnosed with PFIC-1 received ABO compatible living donor LT due to refractory jaundice and pruritus.His mother donated her left lateral segment with a graft-to-recipient weight ratio of 2.9%.Internal BD was constructed during LT using the appendix by connecting its proximal end with the intrahepatic biliary duct and the distal end with colon.Biliary leakage was suspected on the 5th day after transplantation and exploratory laparotomy indicated biliary leakage at the cutting surface of liver.The liver function returned to normal on the 9th day post-operation and maintained normal during the 15-month follow-up.Cholangiography at 10 months after transplantation confirmed the direct secretion of bile into colon.Computerized tomography scan(4 months and 10 months)and liver biopsy(10 months)indicated no steatosis in the allograft.No complaint of recurrent diarrhea,infection or growth retardation was reported during follow-up.CONCLUSION Internal BD using appendix during LT is effective in preventing allograft steatosis and post-transplant infection in PFIC-1 recipients.
基金funded by the National Natural Science Foundation of China(52104046).
文摘Multi-stage and multi-cluster fracturing(MMF)is a crucial technology in unconventional oil and gas development,aiming to enhance production by creating extensive fracture networks.However,achieving uniform expansion of multi-cluster hydraulic fractures(HFs)in MMF remains a significant challenge.Field practice has shown that the use of temporary plugging and diversion fracturing(TPDF)can promote the balanced expansion of multi-cluster HFs.This study conducted TPDF experiments using a true triaxial fracturing simulation system setting a horizontal well completion with multi-cluster jetting perforations to investigate the equilibrium initiation and extension of multi-cluster fractures.The influence of key parameters,including cluster spacing,fracturing fluid viscosity,differential stress,and fracturing fluid injection rate,on fracture initiation and propagation was systematically examined.The results indicate that while close-spaced multi-cluster fracturing significantly increases the number of HFs,it also leads to uneven extension of HFs in their propagation.In contrast,TPDF demonstrates effectiveness in mitigating uneven HF extension,increasing the number of HFs,and creating a larger stimulated reservoir volume,ultimately leading to improved oil and gas well productivity.Moreover,under conditions of high differential stress,the differential stress within the formation exerts a stronger guiding effect in HFs,which are more closely aligned with the minimum principal stress.Low-viscosity fluids facilitate rapid and extensive fracture propagation within the rock formation.High-volume fluid injection,on the other hand,more comprehensively fills the formation.Therefore,employing lowviscosity and high-volume fracturing is advantageous for the initiation and extension of multi-cluster HFs.
