Study on a horizontal axial flow pump during runaway process with bidirectional operating conditions.

The ultra-low head pump stations often have bidirectional demand of water delivery, so there is a risk of runaway accident occurring in both conditions. To analyze the difference of the runaway process under forward runaway condition (FRC) and backward runaway condition (BRC), the whole flow system of a horizontal axial flow pump is considered. The Shear-Stress Transport (SST) k-ω model is adopted and the volume of fluid (VOF) model is applied to simulate the water surface in the reservoirs. Meanwhile, the torque balance equation is introduced to obtain the real time rotational speed, then the bidirectional runaway process of the pump with the same head is simulated. In addition, the vortex transport equation and swirl number are proposed to reveal the flow characteristics during the runaway process. The results show that the runaway process can be divided into five stages: the drop, braking, rising, convergence and runaway stages, according to the changing law of torque curve. In the rising stage, the pressure difference on the blade surface continues to increase, which contributes to the abnormal torque increase. In this stage, the flow hits the pressure surface (PS) at a faster speed enlarging the pressure on PS, and the flow separation takes place on the suction surface (SS) weakening the pressure on SS. During the convergence and runaway stage, the pulsation amplitude of torque and axial force under FRC is obviously larger than those under BRC. This is because the rotation frequency of the vortex rope is the same as main pressure fluctuation frequency in impeller under FRC, which enhances the pulsation amplitude. Whereas the vortices are broken due to the inhibitive effect from guide vanes under BRC.

Habitat changes in the most important stopover sites for the endangered red-crowned crane in China: a large-scale study.

The red-crowned crane (Grus japonensis) is an endangered bird species that has been listed as one of the Class I National Key Protected Wild Animals of China. This study analyzed the habitat changes in the two most important stopover sites for red-crowned crane (Liao River Estuary and Yellow River Delta National Nature Reserves) from 2000 to 2015. The results showed that the landscape patterns of the important stopover sites of red-crowned crane changed obviously and the potential suitable habitat area (tidal flats and marshland) for the red-crowned crane decreased by 183.3 km2, while the area of human activities (including aquaculture waterbodies, farmland and artificial facilities) increased by 140.3 km2. Landscape fragmentation intensified, which could has negative impacts on the survival of the red-crowned crane during migration. A comparative study confirmed that the reduction in marshlands and increasing landscape fragmentation caused by human activities were the main threats in the Liao River Estuary National Nature Reserve, while human activities and natural factors (such as channel flow, rainfall, and sediment discharge) were the jointly driving factors for the reduction in suitable habitats for red-crowned cranes in the Yellow River Delta National Nature Reserve. We suggest there are some loopholes in the management of the two nature reserves, which need to be strengthened urgently in China.

Radium-223 in Asian patients with castration-resistant prostate cancer with symptomatic bone metastases: A single-arm phase 3 study.

AIM: Radium-223, a targeted alpha therapy, is approved widely for the treatment of patients with metastatic castrate-resistant prostate cancer, based on a pivotal phase 3 study in predominantly white patients. We investigated the efficacy and safety of radium-223 in Asian patients with castrate-resistant prostate cancer and metastatic bone disease. METHODS: This multicenter, prospective, single-arm, open-label phase 3 trial evaluated the efficacy and safety of the standard radium-223 regimen (55 kBq/kg every 4 weeks for six cycles) in patients from Asian countries. The primary endpoints were the safety and overall survival. RESULTS: A total of 226 patients were enrolled and received at least one dose of radium-223. Median overall survival was 14.0 months (95% confidence interval [CI], 11.2-17.4). Median time to total alkaline phosphatase and prostate-specific antigen progression were 7.5 (95% CI, 6.8-7.7) and 3.6 (95% CI, 3.1-3.7) months, respectively. Median skeletal-related event-free survival was 26.0 months (95% CI, 12.6-not reached). Grade ≥3 treatment-emergent adverse events were reported in 103 (46%) of 226 patients, with anemia being the most common event (34 [15%] patients). Grade ≥3 drug-related treatment-emergent adverse events occurred in 39 (17%) of 226 patients. Serious treatment-emergent adverse events were reported in 65 (29%) of 226 patients. Seven (3%) patients had an adverse event leading to death; none were considered to be related to radium-223. CONCLUSION: The results of this study support the use of the standard radium-223 regimen for the treatment of Asian patients with castrate-resistant prostate cancer and symptomatic bone metastases.

[Composition analyses of bilateral urinary tract calculis].

OBJECTIVE: To explore the composition of bilateral urinary tract calculi so as to guide treatments. METHODS: A total of 126 patients with bilateral urinary calculi were recruited to undergo percutaneous nephrolithotomy or ureteroscopes lithotripsy. And 256 extracted stones were analyzed by infrared spectrophotometry. RESULTS: The components of these stones were mainly mixture. The compositions included calcium oxalate (n = 214, 85%), carbonate apatite (n = 113, 45%), phosphate (n = 43, 17%) and uric acid (n = 28, 11%). And 63 patients had the same stone composition in bilateral urinary stones and 26 of them were of pure calcium oxalate, 2 phosphate while another 36 mixture. Different compositions were present in 60 patients with bilateral urinary stones. CONCLUSION: The compositions of bilateral urinary stones are not always identical in a patient. The overall patient status should be considered if one side urinary stone is treated according to the composition analysis results of another side counterpart.

Effects of renal pelvic high-pressure perfusion on nephrons in a porcine pyonephrosis model.

The aim of this study was to investigate the effects of various renal pelvic pressure gradients on nephrons with purulent infection. Five miniature test pigs were selected. One side of the kidney was used to prepare the pyonephrosis model and the other side was used as the healthy control. A piezometer and a water fill tube were inserted into the renal pelvis through the ureter. Prior to perfusion, punctures were made on the healthy and purulent sides of the kidneys to obtain tissues (as controls). Subsequently, a puncture biopsy was conducted on the kidneys at five pressure levels: 10, 20, 30, 40 and 50 mmHg. Once the renal pelvic pressure had increased, the healthy and injured kidneys presented pathological changes, including dilation of the renal tubule and capsule and compression of the renal glomerulus. When the renal pelvic pressure exceeded 20 mmHg, the injured kidney presented more damage. Electron microscopy revealed that the increase in pressure resulted in the following: the podocyte gap widened, the epithelial cells of the renal capsule separated from the basement membrane, the basement membrane thickness became uneven, the continuity of the basement membrane was interrupted at multiple positions and the renal tubule microvillus arrangement became disorganised. The manifestations in the pyonephrosis model were more distinct compared with those in the healthy kidney. As the renal pelvic pressure exceeds 20 mmHg under a renal purulent infection status, the nephrons become damaged. The extent of the damage is aggravated as the pressure is increased.

[Transurethral plasmakinetic enucleation of prostate and suprapubic small cut in the treatment of high risk and senior patient with benign prostatic hyperplasia and bladder stones].

OBJECTIVE: To explore the safety and efficiency of transurethral plasmakinetic enucleation of prostate (TUPKEP) and suprapubic small cut in the treatment of high-risk and senior patients with benign prostatic hyperplasia and bladder stones. METHODS: A retrospective review was conducted for 68 high-risk and senior patients with benign prostatic hyperplasia and bladder stones. All of them were treated by TUPKEP and suprapubic small cut. RESULTS: Operation was successfully performed in all 68 cases. And there was no instance of transurethral resection syndrome, shock, myocardial infarct, cerebral infarction, cerebral hemorrhage, permanent urinary incontinence or surgical site infection. Seven patients with temporal urinary incontinence recovered at a mean time of (9.48 ± 1.52) days post-operation. The mean operative duration was (48.63 ± 4.14) min and the mean volume of blood loss (50.97 ± 5.33) ml. The changes of maximum flow rate (Qmax), international prostatic symptom score (I-PSS) and quality-of-life (QOL) were statistically significant before and after operation. Qmax increased from (4.56 ± 0.35) to (18.82 ± 1.65) ml/s (P < 0.001), I-PSS decreased form (21.96 ± 1.89) to (11.23 ± 0.86) (P = 0.018) and QOL decreased from (4.94 ± 0.35) to (1.95 ± 0.32) (P = 0.011). CONCLUSION: The approach of TUPKEP and suprapubic small cut is both safe and effective in the treatment of high-risk and senior patient with benign prostatic hyperplasia and bladder stones and should be widely applied.

[Hemorrhage during and after percutaneous nephrolithotomy via standard nephrostomy tract].

OBJECTIVE: To investigate the intra- and postoperative hemorrhage of percutaneous nephrolithotomy via the standard nephrostomy tract. METHODS: A retrospective analysis was conducted among 1578 patients undergoing percutaneous nephrolithotomy. During the operations, all the nephrostomy tracts were dilated to F24 size after successful puncture. The stones were shattered and removed by EMS lithotrity system. RESULTS: All the patients showed intra- and postoperative hemorrhage, and in 121 cases, blood transfusion was needed. In 18 patients, the operation had to be terminated for severe hemorrhage. The 8 patients with repeated bleeding were managed and cured by blood transfusion and medication. In another 2 cases, severe hemorrhage was found to result from false aneurysms by renal arteriography and managed by superselective embolization. CONCLUSION: Percutaneous nephrolithotomy through standard nephrostomy tract is safe and does not increase the risk of bleeding with careful operation.

[Treatment of calculous pyonephrosis with percutaneous nephrolithotomy via the standard access].

OBJECTIVE: To investigate the feasibility of treatment for calculous pyonephrosis with first stage percutaneous nephrolithotomy under the standard access. METHODS: Thirty-six cases of calculous pyonephrosis and 36 cases of urolithiasis with no pyonephrosis were treated by percutaneous nephrolithotomy. In the nephrostomy, the caliber was dilated to F24. All the operations were preformed through the EMS lithotrity system. The intrapelvic pressure was detected in the operation. The hemoculture before and after operation, the germi culture of urine, and the temperature and blood leucocyte changes after operation were recorded. All the patients were treated by antibiotics before and after the operation. RESULTS: All the patients were treated successfully. The average intrapelvic pressure were 23.2 cmH(2)O in non-pyonephrosis group and 22.8 cmH(2)O in pyonephrosis group. Both of the groups had 1 case of transient bacteremia after the operation. No significant difference was found in the other indices between the two groups. CONCLUSION: EMS lithotrity system is safe and feasible for treating calculous pyonephrosis with stage I percutaneous nephrolithotomy via the standard access.

[Comprehensive therapy for chronic bacterial prostatitis: report of 52 cases].

OBJECTIVE: To evaluate the effects of comprehensive therapy for chronic bacterial prostatitis. METHODS: Comprehensive therapy was prescribed for 52 cases of chronic bacterial prostatitis during June, 2000 to June, 2001, and summaries and analysis of the cases were conducted. RESULTS: Of the 52 cases, 27 (51.9%) were cured and 21 (40.4%) had improvement, while 4 (7.7%) did not respond to the treatment. CONCLUSION: Comprehensive therapy may produce satisfactory effects in treatment of chronic bacterial prostatitis.

Numerical analysis of plasmon-resonance absorption in bisinusoidal metal gratings.

We numerically investigate plasmon-resonance absorption of incident light energy by a bisinusoidal metal grating, i.e., one whose surface profile is sinusoidally corrugated in two orthogonal directions with a common period. Employing Yasuura's modal expansion method, we solve the problem of plane-wave diffraction by the grating and evaluate the absorption, which is observed as dips in diffraction efficiency curves. We examine the field distribution and energy flow in detail at the angles of incidence at which the absorption occurs. We show that the absorption is caused by coupling of the TM component of an evanescent order with surface plasmons. A phase-matching condition is used in the prediction of the incident angle at which the absorption occurs. This, together with the field profile in the presence of the resonance absorption, explains the mechanism of the absorption. We then illustrate interesting features of the absorption: enhancement of polarization conversion between the incident light and the reflected light and simultaneous excitation of two plasmon waves in directions that are symmetric with respect to the plane of incidence.