目的:外固定支架和钢板内固定作为桡骨远端粉碎性骨折的常用治疗方法,在临床上各有利弊。系统评价外固定支架与钢板内固定治疗粉碎性桡骨远端骨折的临床疗效及安全性,为桡骨远端骨折中西医结合诊疗指南研制提供论证依据。方法:系统检索P...目的:外固定支架和钢板内固定作为桡骨远端粉碎性骨折的常用治疗方法,在临床上各有利弊。系统评价外固定支架与钢板内固定治疗粉碎性桡骨远端骨折的临床疗效及安全性,为桡骨远端骨折中西医结合诊疗指南研制提供论证依据。方法:系统检索PubMed、Web of Science、Embase、Cochrane Library、中国知网、中国生物医学文献数据库、维普和万方数据库,纳入2013年10月至2023年10月发表的关于外固定支架和钢板内固定治疗粉碎性桡骨远端骨折的随机对照试验文献,按照纳入标准和排除标准筛选文献,使用Review Manager进行文献质量评价和Meta分析。结果:(1)纳入8篇文献,其中中文文献4篇,英文文献4篇、总样本量648例,外固定支架组328例,钢板内固定组320例;(2)术后3个月,钢板内固定组的背伸、掌屈、旋后范围优于外固定支架组;术后12个月,钢板内固定组的握力、掌倾角、掌屈、旋前和旋后范围优于外固定支架组;钢板内固定组在术后感染方面优于外固定支架组,其余结局指标两组差异均无显著性意义。结论:现有8项证据表明,在粉碎性桡骨远端骨折的治疗方式选择上,外固定支架与切开钢板内固定都有良好的治疗效果,综合其他因素钢板内固定更胜一筹,但是对于一些高度严重的粉碎性桡骨远端骨折、骨质较差、严重污染的开放性骨折以及软组织肿胀而无法进行切开手术的特殊患者,外固定支架才是首选。此次研究结果具有局限性,未来还需要开展更多高质量、大样本、多中心的随机对照试验研究,另外需重视远期疗效、其他次要指标的观察,补充优化当前研究结果。展开更多
The field data of shale fracturing demonstrate that the flowback performance of fracturing fluid is different from that of conventional reservoirs,where the flowback rate of shale fracturing fluid is lower than that o...The field data of shale fracturing demonstrate that the flowback performance of fracturing fluid is different from that of conventional reservoirs,where the flowback rate of shale fracturing fluid is lower than that of conventional reservoirs.At the early stage of flowback,there is no single-phase flow of the liquid phase in shale,but rather a gas-water two-phase flow,such that the single-phase flow model for tight oil and gas reservoirs is not applicable.In this study,pores and microfractures are extracted based on the experimental results of computed tomography(CT)scanning,and a spatial model of microfractures is established.Then,the influence of rough microfracture surfaces on the flow is corrected using the modified cubic law,which was modified by introducing the average deviation of the microfracture height as a roughness factor to consider the influence of microfracture surface roughness.The flow in the fracture network is simulated using the modified cubic law and the lattice Boltzmann method(LBM).The results obtained demonstrate that most of the fracturing fluid is retained in the shale microfractures,which explains the low fracturing fluid flowback rate in shale hydraulic fracturing.展开更多
BACKGROUND Dislocation rates after hemiarthroplasty reportedly vary from 1%to 17%.This serious complication is associated with increased morbidity and mortality rates.Approaches to this surgery are still debated,with ...BACKGROUND Dislocation rates after hemiarthroplasty reportedly vary from 1%to 17%.This serious complication is associated with increased morbidity and mortality rates.Approaches to this surgery are still debated,with no consensus regarding the superiority of any single approach.AIM To compare early postoperative complications after implementing the direct anterior and posterior approaches(PL)for hip hemiarthroplasty after femoral neck fractures.METHODS This is a comparative,retrospective,single-center cohort study conducted at a university hospital.Between March 2008 and December 2018,273 patients(a total of 280 hips)underwent bipolar hemiarthroplasties(n=280)for displaced femoral neck fractures using either the PL(n=171)or the minimally invasive direct anterior approach(DAA)(n=109).The choice of approach was related to the surgeons’practices;the implant types were similar and unrelated to the approach.Dislocation rates and other complications were reviewed after a minimum followup of 6 mo.RESULTS Both treatment groups had similarly aged patients(mean age:82 years),sex ratios,patient body mass indexes,and patient comorbidities.Surgical data(surgery delay time,operative time,and blood loss volume)did not differ significantly between the groups.The 30 d mortality rate was higher in the PL group(9.9%)than in the DAA group(3.7%),but the difference was not statistically significant(P=0.052).Among the one-month survivors,a significantly higher rate of dislocation was observed in the PL group(14/154;9.1%)than in the DAA group(0/105;0%)(P=0.002).Of the 14 patients with dislocation,8 underwent revision surgery for recurrent instability(posterior group),and one of them had 2 additional procedures due to a deep infection.The rate of other complications(e.g.,perioperative and early postoperative periprosthetic fractures and infection-related complications)did not differ significantly between the groups.CONCLUSION These findings suggest that the DAA to bipolar hemiarthroplasty for patients with femoral neck fractures is associated with a lower dislocation rate(<1%)than the PL.展开更多
The stability and mobility of proppant packs in hydraulic fractures during hydrocarbon production are numerically investigated by the lattice Boltzmann-discrete element coupling method(LB-DEM).This study starts with a...The stability and mobility of proppant packs in hydraulic fractures during hydrocarbon production are numerically investigated by the lattice Boltzmann-discrete element coupling method(LB-DEM).This study starts with a preliminary proppant settling test,from which a solid volume fraction of 0.575 is calibrated for the proppant pack in the fracture.In the established workflow to investigate proppant flowback,a displacement is applied to the fracture surfaces to compact the generated proppant pack as well as further mimicking proppant embedment under closure stress.When a pressure gradient is applied to drive the fluid-particle flow,a critical aperture-to-diameter ratio of 4 is observed,above which the proppant pack would collapse.The results also show that the volumetric proppant flowback rate increases quadratically with the fracture aperture,while a linear variation between the particle flux and the pressure gradient is exhibited for a fixed fracture aperture.The research outcome contributes towards an improved understanding of proppant flowback in hydraulic fractures,which also supports an optimised proppant size selection for hydraulic fracturing operations.展开更多
文摘目的:外固定支架和钢板内固定作为桡骨远端粉碎性骨折的常用治疗方法,在临床上各有利弊。系统评价外固定支架与钢板内固定治疗粉碎性桡骨远端骨折的临床疗效及安全性,为桡骨远端骨折中西医结合诊疗指南研制提供论证依据。方法:系统检索PubMed、Web of Science、Embase、Cochrane Library、中国知网、中国生物医学文献数据库、维普和万方数据库,纳入2013年10月至2023年10月发表的关于外固定支架和钢板内固定治疗粉碎性桡骨远端骨折的随机对照试验文献,按照纳入标准和排除标准筛选文献,使用Review Manager进行文献质量评价和Meta分析。结果:(1)纳入8篇文献,其中中文文献4篇,英文文献4篇、总样本量648例,外固定支架组328例,钢板内固定组320例;(2)术后3个月,钢板内固定组的背伸、掌屈、旋后范围优于外固定支架组;术后12个月,钢板内固定组的握力、掌倾角、掌屈、旋前和旋后范围优于外固定支架组;钢板内固定组在术后感染方面优于外固定支架组,其余结局指标两组差异均无显著性意义。结论:现有8项证据表明,在粉碎性桡骨远端骨折的治疗方式选择上,外固定支架与切开钢板内固定都有良好的治疗效果,综合其他因素钢板内固定更胜一筹,但是对于一些高度严重的粉碎性桡骨远端骨折、骨质较差、严重污染的开放性骨折以及软组织肿胀而无法进行切开手术的特殊患者,外固定支架才是首选。此次研究结果具有局限性,未来还需要开展更多高质量、大样本、多中心的随机对照试验研究,另外需重视远期疗效、其他次要指标的观察,补充优化当前研究结果。
基金supported by the National Natural Science Foundation of China(Grant No.52022087).
文摘The field data of shale fracturing demonstrate that the flowback performance of fracturing fluid is different from that of conventional reservoirs,where the flowback rate of shale fracturing fluid is lower than that of conventional reservoirs.At the early stage of flowback,there is no single-phase flow of the liquid phase in shale,but rather a gas-water two-phase flow,such that the single-phase flow model for tight oil and gas reservoirs is not applicable.In this study,pores and microfractures are extracted based on the experimental results of computed tomography(CT)scanning,and a spatial model of microfractures is established.Then,the influence of rough microfracture surfaces on the flow is corrected using the modified cubic law,which was modified by introducing the average deviation of the microfracture height as a roughness factor to consider the influence of microfracture surface roughness.The flow in the fracture network is simulated using the modified cubic law and the lattice Boltzmann method(LBM).The results obtained demonstrate that most of the fracturing fluid is retained in the shale microfractures,which explains the low fracturing fluid flowback rate in shale hydraulic fracturing.
基金This study was reviewed and approved by the Ethics Committee of the HUB-Hospital Erasme.
文摘BACKGROUND Dislocation rates after hemiarthroplasty reportedly vary from 1%to 17%.This serious complication is associated with increased morbidity and mortality rates.Approaches to this surgery are still debated,with no consensus regarding the superiority of any single approach.AIM To compare early postoperative complications after implementing the direct anterior and posterior approaches(PL)for hip hemiarthroplasty after femoral neck fractures.METHODS This is a comparative,retrospective,single-center cohort study conducted at a university hospital.Between March 2008 and December 2018,273 patients(a total of 280 hips)underwent bipolar hemiarthroplasties(n=280)for displaced femoral neck fractures using either the PL(n=171)or the minimally invasive direct anterior approach(DAA)(n=109).The choice of approach was related to the surgeons’practices;the implant types were similar and unrelated to the approach.Dislocation rates and other complications were reviewed after a minimum followup of 6 mo.RESULTS Both treatment groups had similarly aged patients(mean age:82 years),sex ratios,patient body mass indexes,and patient comorbidities.Surgical data(surgery delay time,operative time,and blood loss volume)did not differ significantly between the groups.The 30 d mortality rate was higher in the PL group(9.9%)than in the DAA group(3.7%),but the difference was not statistically significant(P=0.052).Among the one-month survivors,a significantly higher rate of dislocation was observed in the PL group(14/154;9.1%)than in the DAA group(0/105;0%)(P=0.002).Of the 14 patients with dislocation,8 underwent revision surgery for recurrent instability(posterior group),and one of them had 2 additional procedures due to a deep infection.The rate of other complications(e.g.,perioperative and early postoperative periprosthetic fractures and infection-related complications)did not differ significantly between the groups.CONCLUSION These findings suggest that the DAA to bipolar hemiarthroplasty for patients with femoral neck fractures is associated with a lower dislocation rate(<1%)than the PL.
基金Funding support from Heilongjiang"Open Competition"project(Grant No.DQYT2022-JS-758)is greatly acknowledgedFinancial support from the National Natural Science Foundation of China(Grant Nos.52304025 and 52174025)is acknowledged+1 种基金supports from Northeast Petroleum University and Guangdong Basic and Applied Basic Research Foundationsupport from the Heilongjiang Touyan Innovation Team Program.
文摘The stability and mobility of proppant packs in hydraulic fractures during hydrocarbon production are numerically investigated by the lattice Boltzmann-discrete element coupling method(LB-DEM).This study starts with a preliminary proppant settling test,from which a solid volume fraction of 0.575 is calibrated for the proppant pack in the fracture.In the established workflow to investigate proppant flowback,a displacement is applied to the fracture surfaces to compact the generated proppant pack as well as further mimicking proppant embedment under closure stress.When a pressure gradient is applied to drive the fluid-particle flow,a critical aperture-to-diameter ratio of 4 is observed,above which the proppant pack would collapse.The results also show that the volumetric proppant flowback rate increases quadratically with the fracture aperture,while a linear variation between the particle flux and the pressure gradient is exhibited for a fixed fracture aperture.The research outcome contributes towards an improved understanding of proppant flowback in hydraulic fractures,which also supports an optimised proppant size selection for hydraulic fracturing operations.
