The long-term existence of dam structures significantly modified the river channel. In accordance with a drastic increase of low-head dams under consideration for removal in recent years, it is important to predict th...The long-term existence of dam structures significantly modified the river channel. In accordance with a drastic increase of low-head dams under consideration for removal in recent years, it is important to predict the effects of low-head dam removal from the modified river channel by the low-head dam construction. This study intends to investigate the long-term channel evolution process following low-head construction and removal and to find out the influential parameters (sediment diameter, river bed slope, dam height) for those channel evolution by two-dimensional numerical simulation model. Following the low-head dam construction, sediment deposition rates in upstream of the low-head dam are varied with the influential parameters. The sediment deposition rates and sandbar formation with riparian vegetation settlement on sandbars have significantly affected for channel evolution following low-head dam removal. Especially the knickpoint formation and the types of vegetation (grass type and tree type) on the sandbars are critical factors for channel evolution following low-head dam removal. Through the numerical simulation results of low-head dam construction (50 years) and low-head dam removal (50 years), it is identified that the modified river channel by low-head dam may not be easily restored to pre-dam conditions following its removal especially in river geomorphology and riparian vegetation. Consequently, this study found that the reversibility following low-head dam construction and removal depends on the sediment deposition rates in upstream of the low-head dam.展开更多
Emerging evidence has suggested that cytoreductive prostatectomy （CRP） allows superior oncologic control when compared to current standard of care androgen deprivation therapy alone. However, the safety and benefit ...Emerging evidence has suggested that cytoreductive prostatectomy （CRP） allows superior oncologic control when compared to current standard of care androgen deprivation therapy alone. However, the safety and benefit of cytoreduction in metastatic prostate cancer （mPCa） has not been proven. Therefore, we evaluated the incidence of complications following CRP in men newly diagnosed with mPCa. A total of 68 patients who underwent CRP from 2006 to 2014 at four tertiary surgical centers were compared to 598 men who underwent radical prostatectomy for clinically localized prostate cancer （PCa）. Urinary incontinence was defined as the use of any pad. CRP had longer operative times （200 min vs 140 min, P 〈 0.0001） and higher estimated blood loss （250 ml vs 125 ml, P 〈 0.0001） compared to the control group. However, both overall （8.82% vs 5.85%） and major complication rates （4.41% vs 2.17%） were comparable between the two groups. Importantly, urinary incontinence rate at 1-year after surgery was significantly higher in the CRP group （57.4% vs 90.8%, P 〈 0.0001）. Univariate logistic analysis showed that the estimated blood loss was the only independent predictor of perioperative complications both in the unadjusted model （OR： 1.18; 95% Ch 1.02-1.37; P= 0.025） and surgery type-adjusted model （OR： 1.17; 95% Ch 1.01-1.36; P= 0.034）. In conclusion, CRP is more challenging than radical prostatectomy and associated with a notably higher incidence of urinary incontinence. Nevertheless, CRP is a technically feasible and safe surgery for selecting PCa patients who present with node-positive or bony metastasis when performed by experienced surgeons. A prospective, multi-institutional clinical trial is currently underway to verify this concept.展开更多
文摘The long-term existence of dam structures significantly modified the river channel. In accordance with a drastic increase of low-head dams under consideration for removal in recent years, it is important to predict the effects of low-head dam removal from the modified river channel by the low-head dam construction. This study intends to investigate the long-term channel evolution process following low-head construction and removal and to find out the influential parameters (sediment diameter, river bed slope, dam height) for those channel evolution by two-dimensional numerical simulation model. Following the low-head dam construction, sediment deposition rates in upstream of the low-head dam are varied with the influential parameters. The sediment deposition rates and sandbar formation with riparian vegetation settlement on sandbars have significantly affected for channel evolution following low-head dam removal. Especially the knickpoint formation and the types of vegetation (grass type and tree type) on the sandbars are critical factors for channel evolution following low-head dam removal. Through the numerical simulation results of low-head dam construction (50 years) and low-head dam removal (50 years), it is identified that the modified river channel by low-head dam may not be easily restored to pre-dam conditions following its removal especially in river geomorphology and riparian vegetation. Consequently, this study found that the reversibility following low-head dam construction and removal depends on the sediment deposition rates in upstream of the low-head dam.
文摘Emerging evidence has suggested that cytoreductive prostatectomy （CRP） allows superior oncologic control when compared to current standard of care androgen deprivation therapy alone. However, the safety and benefit of cytoreduction in metastatic prostate cancer （mPCa） has not been proven. Therefore, we evaluated the incidence of complications following CRP in men newly diagnosed with mPCa. A total of 68 patients who underwent CRP from 2006 to 2014 at four tertiary surgical centers were compared to 598 men who underwent radical prostatectomy for clinically localized prostate cancer （PCa）. Urinary incontinence was defined as the use of any pad. CRP had longer operative times （200 min vs 140 min, P 〈 0.0001） and higher estimated blood loss （250 ml vs 125 ml, P 〈 0.0001） compared to the control group. However, both overall （8.82% vs 5.85%） and major complication rates （4.41% vs 2.17%） were comparable between the two groups. Importantly, urinary incontinence rate at 1-year after surgery was significantly higher in the CRP group （57.4% vs 90.8%, P 〈 0.0001）. Univariate logistic analysis showed that the estimated blood loss was the only independent predictor of perioperative complications both in the unadjusted model （OR： 1.18; 95% Ch 1.02-1.37; P= 0.025） and surgery type-adjusted model （OR： 1.17; 95% Ch 1.01-1.36; P= 0.034）. In conclusion, CRP is more challenging than radical prostatectomy and associated with a notably higher incidence of urinary incontinence. Nevertheless, CRP is a technically feasible and safe surgery for selecting PCa patients who present with node-positive or bony metastasis when performed by experienced surgeons. A prospective, multi-institutional clinical trial is currently underway to verify this concept.
