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EFFECT OF TIP CLEARANCE ON PERFORMANCE AND FLOW FIELD OF SMALL SIZED HIGH SPEED CENTRIFUGAL FAN 被引量:2
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作者 曹人靖 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2005年第4期329-334,共6页
A centrifugal fan with the high speed and compact dimensions is studied numerically and experimentally. The centrifugal fan consists of a shrouded impeller rotating at 34 000 r/min with a small tip clearance 0.7 mm to... A centrifugal fan with the high speed and compact dimensions is studied numerically and experimentally. The centrifugal fan consists of a shrouded impeller rotating at 34 000 r/min with a small tip clearance 0.7 mm to the fixed outer casing. Computational models with/without the tip clearance are built and the κ-ω shear stress transport (SST) turbulence model and the unstructured mesh are applied to the numerical simulation for unsteady solutions. The overall performance is measured on a standard experimental bench and the major flow feature of each component inside the centrifugal fan is numerically investigated. In the presence of the tip clearance due to the difference of static pressure between leading and trailing edges of the clearance, i. e. , leading and trailing edges of the impeller, a strong return flow exists inside the clearance passage and re-circulates the main stream inside the impeller passage, and produces the strong flow interaction, thus changing the flow field and influencing the overall performance. 展开更多
关键词 small sized high speed centrifugal fan tip clearance flow field analysis
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Study on the Topographic Effect on Soil Erosion Using RUSLE Model for Small Size Watershed
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作者 CHEN Chuan-sheng JIANG Xin 《水土保持研究》 CSCD 北大核心 2006年第5期186-187,192,共3页
Soil erosion and subsequent sedimentation have caused serious environmental and soil degradation problems in Okinawa Prefecture,Japan.This research aims at evaluating an availability of the Revised Universal Soil loss... Soil erosion and subsequent sedimentation have caused serious environmental and soil degradation problems in Okinawa Prefecture,Japan.This research aims at evaluating an availability of the Revised Universal Soil loss Equation(RUSLE) for predicting the range of soil loss values for the Nago watershed in Okinawa.It shows that climatic conditions substantially influence the rainfall amount as a function of the I30 of the rainfall event.The rate of soil loss is higher with increasing in altitude due to greater slope steepness.By rainfall data analysis,it is concluded that the large difference in soil loss between 2000 and 2001 was due to concentrated heavy rainfall in the rainy season or the typhoon season. 展开更多
关键词 RUSLE erosion index RAINFALL soil loss small size watershed
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Study of Magnetic Force Distribution for Electromagnetic V-shape Bending Forming of Small Size Flat Sheet
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作者 Xiao-Wei Chen Wen-Ping Wang +5 位作者 Min Wan Long Pan An-Lin Long Wei-Ren Xiong Cheng-Long Shi Zhong-Yu Zhou 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2014年第1期25-31,共7页
Electromagnetic V-shape bending of small size sheet blank is investigated numerically and experimentally. Three-dimensional electromagnetic field models are established to calculate the magnetic force distribution on ... Electromagnetic V-shape bending of small size sheet blank is investigated numerically and experimentally. Three-dimensional electromagnetic field models are established to calculate the magnetic force distribution on the sheet by software ANSYS / EMAG. Series of electromagnetic V-shape bending forming experiments are presented,in which small size uniform pressure coil and big size round flat spiral coil are used. The results show that small size uniform pressure coil is not suitable for electromagnetic forming of small size flat sheet,and the coil is susceptible to failure such as bulging,ablation and cracking. When the plane dimension of round flat spiral coil is bigger than sheet blank sizes,the induced current crowding effect will be resulted which seriously influence the magnetic force distribution on the sheet. In this case,magnetic force distribution can be adjusted through the change of the relative position between coil and sheet,the desired deformation can be obtained finally. Therefore,big size round flat spiral coil can be well applied to electromagnetic V-shape bending forming of small size flat sheet. 展开更多
关键词 Electromagnetic forming small size sheet blank Induced current crowding effect Magnetic force distribution
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The Research and Analysis to the Financing Dilemma and Countermeasures of China's Medium and Small Sized High-tech Enterprises
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作者 Wang Zhi 《International English Education Research》 2014年第8期36-38,共3页
The Financing problem of Medium and small Sized High-tech Enterprises is the key point to enterprises' survival and development. Firstly it is pointed out that the difficulty in financing is due to without enough emp... The Financing problem of Medium and small Sized High-tech Enterprises is the key point to enterprises' survival and development. Firstly it is pointed out that the difficulty in financing is due to without enough emphasis on Medium and Small Sized High-tech Enterprises, without sound targeted laws and regulations, the imperfect credit guarantee system, and corporate governance structure problem of the enterprise Then, according to the problems existing in the financing of China's Medium and Small Sized High-tech Enterprises, the assay put forward several countermeasures which have referential value. 展开更多
关键词 Medium and small sized High-tech Enterprises FINANCING COUNTERMEASURES
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The New Molecular Entity Evolocumab, One Kind of PCSK9 Inhibitor, Reduce Plasma Small Size LDL-Cholesterol Levels by Using a New Standardized Method of Measuring LDL Size
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作者 Ikuo Inoue Ryo Kubota +5 位作者 Shohan Yanagi Masumi Akita Takanari Nakano Shigehiro Katayama Akira Shimada Mistuhiko Noda 《Open Journal of Molecular and Integrative Physiology》 2017年第1期1-23,共23页
Aims: There has been no evidence on the effects of evolocumab, protein convertase subtilisin/kexin type 9 (PCSK9) inhibitor, on small size LDL. We observationally investigated the efficacy and side effects of evolocum... Aims: There has been no evidence on the effects of evolocumab, protein convertase subtilisin/kexin type 9 (PCSK9) inhibitor, on small size LDL. We observationally investigated the efficacy and side effects of evolocumab on the LDL subfraction particle diameter using PAGE system for lipoprotein analysis. Methods: We defined 30 patients with high-risk hyperlipidemia. As for analysis of LDL subfraction profile, we used polyacrylamide gel electrophoresis three methods: 1) 3% nondenatured poly-acrylamide gel electrophoresis method (3%PAGE), 2) 2% - 16% nondenatured poly-acrylamide gradient gel electro-phoresis method (2% - 16% GGE) and 3) 2.7% - 5% GGE. Evolocumab 140 mg/day administered together with statin significantly improved serum total cholesterol (TC), triglyceride (TG), high-dense lipoprotein-cholesterol (HDL-C), and LDL-C after four-week treatment. Results: TC, TG, HDL-C and LDL-C levels were improved by, respectively, 33%, 20%, 10%, and 54%. The mean LDL size significantly increased from 25.6 ± 0.4 nm to 26.4 ± 0.8 nm. The small dense LDL-cholesterol (sdLDL-C), large buoyant LDL-cholesterol (lbLDL-C), and mid-band lipoprotein-cholesterol were reduced, respectively. Therefore, the preliminary study on this paper can be the first step into a new insight on the world of lipid metabolism. Conclusion: Short-term administration of evolocumab addedons to statin therapy, significantly reduced small size LDL levels. 展开更多
关键词 PCSK9 INHIBITOR Evolocumab LDL Heterogeneicity small size LDL 3% PAGE 2% - 16% GGE
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Research on aiming methods for small sample size shooting tests of two-dimensional trajectory correction fuse
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作者 Chen Liang Qiang Shen +4 位作者 Zilong Deng Hongyun Li Wenyang Pu Lingyun Tian Ziyang Lin 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期506-517,共12页
The longitudinal dispersion of the projectile in shooting tests of two-dimensional trajectory corrections fused with fixed canards is extremely large that it sometimes exceeds the correction ability of the correction ... The longitudinal dispersion of the projectile in shooting tests of two-dimensional trajectory corrections fused with fixed canards is extremely large that it sometimes exceeds the correction ability of the correction fuse actuator.The impact point easily deviates from the target,and thus the correction result cannot be readily evaluated.However,the cost of shooting tests is considerably high to conduct many tests for data collection.To address this issue,this study proposes an aiming method for shooting tests based on small sample size.The proposed method uses the Bootstrap method to expand the test data;repeatedly iterates and corrects the position of the simulated theoretical impact points through an improved compatibility test method;and dynamically adjusts the weight of the prior distribution of simulation results based on Kullback-Leibler divergence,which to some extent avoids the real data being"submerged"by the simulation data and achieves the fusion Bayesian estimation of the dispersion center.The experimental results show that when the simulation accuracy is sufficiently high,the proposed method yields a smaller mean-square deviation in estimating the dispersion center and higher shooting accuracy than those of the three comparison methods,which is more conducive to reflecting the effect of the control algorithm and facilitating test personnel to iterate their proposed structures and algorithms.;in addition,this study provides a knowledge base for further comprehensive studies in the future. 展开更多
关键词 Two-dimensional trajectory correction fuse small sample size test Compatibility test KL divergence Fusion bayesian estimation
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Contract Mechanism of Water Environment Regulation for Small and Medium Sized Enterprises Based on Optimal Control Theory
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作者 Shuang Zhao Hongbin Gu +2 位作者 Lianfang Xue Dongsheng Wang Bin Huang 《Journal of Water Resource and Protection》 CAS 2024年第7期538-556,共20页
The small and scattered enterprise pattern in the county economy has formed numerous sporadic pollution sources, hindering the centralized treatment of the water environment, increasing the cost and difficulty of trea... The small and scattered enterprise pattern in the county economy has formed numerous sporadic pollution sources, hindering the centralized treatment of the water environment, increasing the cost and difficulty of treatment. How enterprises can make reasonable decisions on their water environment behavior based on the external environment and their own factors is of great significance for scientifically and effectively designing water environment regulation mechanisms. Based on optimal control theory, this study investigates the design of contractual mechanisms for water environmental regulation for small and medium-sized enterprises. The enterprise is regarded as an independent economic entity that can adopt optimal control strategies to maximize its own interests. Based on the participation of multiple subjects including the government, enterprises, and the public, an optimal control strategy model for enterprises under contractual water environmental regulation is constructed using optimal control theory, and a method for calculating the amount of unit pollutant penalties is derived. The water pollutant treatment cost data of a paper company is selected to conduct empirical numerical analysis on the model. The results show that the increase in the probability of government regulation and public participation, as well as the decrease in local government protection for enterprises, can achieve the same regulatory effect while reducing the number of administrative penalties per unit. Finally, the implementation process of contractual water environmental regulation for small and medium-sized enterprises is designed. 展开更多
关键词 Optimal Control Theory small and Medium-sized Enterprises Water Environment Regulation Contract Mechanism
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Full well capacity and quantum efficiency optimization for small size backside illuminated CMOS image pixels with a new photodiode structure 被引量:4
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作者 孙羽 张平 +2 位作者 徐江涛 高志远 徐超 《Journal of Semiconductors》 EI CAS CSCD 2012年第12期42-48,共7页
To improve the full well capacity (FWC) of a small size backside illuminated (BSI) CMOS image sensor (CIS), the effect of photodiode capacitance (Cpo) on FWC is studied, and a reformed pinned photodiode (PPD... To improve the full well capacity (FWC) of a small size backside illuminated (BSI) CMOS image sensor (CIS), the effect of photodiode capacitance (Cpo) on FWC is studied, and a reformed pinned photodiode (PPD) structure is proposed. Two procedures are implemented for the optimization. The first is to form a varying doping concentration and depth stretched new N region, which is implemented by an additional higher-energy and lower-dose N type implant beneath the original N region. The FWC of this structure is increased by extending the side wall junctions in the substrate. Secondly, in order to help the enlarged well capacity achieve full depletion, two step P-type implants with different implant energies are introduced to form a P-type insertion region in the interior of the stretched N region. This vertical inserted P region guarantees that the proposed new PD structure achieves full depletion in the reset period. The simulation results show that the FWC can be improved from 1289e- to 6390e-, and this improvement does not sacrifice any image lag performance. Additionally, quantum efficiency (QE) is enhanced in the full wavelength range, especially 6.3% at 520 nm wavelength. This technique can not only be used in such BSI structures, but also adopted in an FSI pixel with any photodiode-type readout scheme. 展开更多
关键词 backside illuminated CMOS image sensor PHOTODIODE full well capacity quantum efficiency small size pixel
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New Thought about the Marketing Orientation of Middle and Small-sized Enterprises of China
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作者 Dongpo Chang 《Chinese Business Review》 2006年第1期21-23,29,共4页
The reasonable marketing orientation is related to the survival and the development of the enterprises. According to the disadvantages and superiority of the middle and small sized enterprises of our country, this pap... The reasonable marketing orientation is related to the survival and the development of the enterprises. According to the disadvantages and superiority of the middle and small sized enterprises of our country, this paper analyzes the new thought about the marketing orientation from the aspects of marketing product orientation, marketing way orientation, marketing target orientation, marketing strategy orientation and marketing idea orientation. It has great theoretical and practical significance. 展开更多
关键词 middle and small sized enterprises marketing product orientation target orientation strategy orientation idea orientation
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Reliability Assessment for the Solenoid Valve of a High-Speed Train Braking System under Small Sample Size 被引量:9
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作者 Jian-Wei Yang Jin-Hai Wang +1 位作者 Qiang Huang Ming Zhou 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2018年第3期189-199,共11页
Reliability assessment of the braking system in a high?speed train under small sample size and zero?failure data is veryimportant for safe operation. Traditional reliability assessment methods are only performed well ... Reliability assessment of the braking system in a high?speed train under small sample size and zero?failure data is veryimportant for safe operation. Traditional reliability assessment methods are only performed well under conditions of large sample size and complete failure data,which lead to large deviation under conditions of small sample size and zero?failure data. To improve this problem,a new Bayesian method is proposed. Based on the characteristics of the solenoid valve in the braking system of a high?speed train,the modified Weibull distribution is selected to describe the failure rate over the entire lifetime. Based on the assumption of a binomial distribution for the failure probability at censored time,a concave method is employed to obtain the relationships between accumulation failure prob?abilities. A numerical simulation is performed to compare the results of the proposed method with those obtained from maximum likelihood estimation,and to illustrate that the proposed Bayesian model exhibits a better accuracy for the expectation value when the sample size is less than 12. Finally,the robustness of the model is demonstrated by obtaining the reliability indicators for a numerical case involving the solenoid valve of the braking system,which shows that the change in the reliability and failure rate among the di erent hyperparameters is small. The method is provided to avoid misleading of subjective information and improve accuracy of reliability assessment under condi?tions of small sample size and zero?failure data. 展开更多
关键词 Zero?failure data Modified Weibull distribution small sample size Bayesian method
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Small for size syndrome difficult dilemma: Lessons from 10 years single centre experience in living donor liver transplantation 被引量:3
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作者 Hany Shoreem Emad Hamdy Gad +8 位作者 Hosam Soliman Osama Hegazy Sherif Saleh Hazem Zakaria Eslam Ayoub Yasmin Kamel Kalid Abouelella Tarek Ibrahim Ibrahim Marawan 《World Journal of Hepatology》 CAS 2017年第21期930-944,共15页
AIM To analyze the incidence, risk factors, prevention, treatment and outcome of small for size syndrome(SFSS) after living donor liver transplantation(LDLT). METHODS Through-out more than 10 years: During the period ... AIM To analyze the incidence, risk factors, prevention, treatment and outcome of small for size syndrome(SFSS) after living donor liver transplantation(LDLT). METHODS Through-out more than 10 years: During the period from April 2003 to the end of 2013, 174 adult-to-adults LDLT(A-ALDLT) had been performed at National Liver Institute, Menoufiya University, Shibin Elkoom, Egypt. We collected the data of those patients to do this cohort study that is a single-institution retrospective analysis of a prospectively collected database analyzing the incidence, risk factors, prevention, treatment and outcome of SFSS in a period started from the end of 2013 to the end of 2015. The median period of follow-up reached 40.50 m, range(0-144 m). RESULTS SFSS was diagnosed in 20(11.5%) of our recipients. While extra-small graft [small for size graft(SFSG)], portal hypertension, steatosis and left lobe graft were significant predictors of SFSS in univariate analysis(P = 0.00, 0.04, 0.03, and 0.00 respectively); graft size was the only independent predictor of SFSS on multivariate analysis(P = 0.03). On the other hand, there was lower incidence of SFSS in patients with SFSG who underwent splenectomy [4/10(40%) SFSS vs 3/7(42.9%) no SFSS] but without statistical significance, However, there was none significant lower incidence of the syndrome in patients with right lobe(RL) graft when drainage of the right anterior and/or posterior liver sectors by middle hepatic vein, V5, V8, and/or right inferior vein was done [4/10(28.6%) SFSS vs 52/152(34.2%) no SFSS]. The 6-mo, 1-, 3-, 5-, 7-and 10-year survival in patients with SFSS were 30%, 30%, 25%, 25%, 25% and 25% respectively, while, the 6-mo, 1-, 3-, 5-, 7-and 10-year survival in patients without SFSS were 70.1%, 65.6%, 61.7%, 61%, 59.7%, and 59.7% respectively, with statistical significant difference(P = 0.00). CONCLUSION SFSG is the independent and main factor for occurrence of SFSS after A-ALDLT leading to poor outcome. However, the management of this catastrophe depends upon its prevention(i.e., selecting graft with proper size, splenectomy to decrease portal venous inflow, and improving hepatic vein outflow by reconstructing large draining veins of the graft). 展开更多
关键词 Living donor liver transplantation Outcome after living donor liver transplantation small for size syndrome small for size graft Portal inflow Venous outflow
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Outcomes of right-lobe and left-lobe living-donor liver transplantations using small-for-size grafts 被引量:4
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作者 Wong Hoi She Kenneth SH Chok +2 位作者 James YY Fung Albert CY Chan Chung Mau Lo 《World Journal of Gastroenterology》 SCIE CAS 2017年第23期4270-4277,共8页
AIM To analyze the outcomes of living-donor liver transplantation(LDLT) using left-lobe(LL) or right-lobe(RL) small-for-size(SFS) grafts.METHODS Prospectively collected data of adult patients who underwent LDLT at our... AIM To analyze the outcomes of living-donor liver transplantation(LDLT) using left-lobe(LL) or right-lobe(RL) small-for-size(SFS) grafts.METHODS Prospectively collected data of adult patients who underwent LDLT at our hospital in the period from January 2003 to December 2013 were reviewed. The patients were divided into the RL-LDLT group and the LL-LDLT group. The two groups were compared in terms of short-and long-term outcomes, including incidence of postoperative complication, graft function, graft survival, and patient survival. A SFS graft was defined as a graft with a ratio of graft weight(GW) to recipient standard liver volume(RSLV)(GW/RSLV) of < 50%. The Urata formula was used to estimate RSLV.RESULTS Totally 218 patients were included for analysis, with 199 patients in the RL-LDLT group and 19 patients in the LL-LDLT group. The two groups were similar in terms of age(median, 53 years in the RL-LDLT group and 52 years in the LL-LDLT group, P = 0.997) but had significantly different ratios of men to women(165:34 in the RL-LDLT group and 8:11 in the LL-LDLT group, P < 0.0001). The two groups were also significantly different in GW(P < 0.0001), GW/RSLV(P < 0.0001), and graft cold ischemic time(P = 0.007). When it comes to postoperative complication, the groups were comparable(P = 0.105). Five patients died in hospital,4(2%) in the RL-LDLT group and 1(5.3%) in the LLLDLT group(P = 0.918). There were 38 graft losses, 33(16.6%) in the RL-LDLT group and 5(26.3%) in the LL-LDLT group(P = 0.452). The 5-year graft survival rate was significantly better in the RL-LDLT group(95.2% vs 89.5%, P = 0.049). The two groups had similar 5-year patient survival rates(RL-LDLT: 86.8%, LL-LDLT: 89.5%, P = 0.476).CONCLUSION The use of SFS graft in LDLT requires careful tailormade surgical planning and meticulous operation. LLLDLT can be a good alternative to RL-LDLT with similar recipient outcomes but a lower donor risk. Further research into different patient conditions is needed in order to validate the use of LL graft. 展开更多
关键词 small for size liver graft Right lobe graft Left lobe graft Living donor liver transplantation
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Impact of small-for-size liver grafts on medium-term and long-term graft survival in living donor liver transplantation: A meta-analysis 被引量:3
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作者 Ka Wing Ma Kelly Hiu Ching Wong +6 位作者 Albert Chi Yan Chan Tan To Cheung Wing Chiu Dai James Yan Yue Fung Wong Hoi She Chung Mau Lo Kenneth Siu Ho Chok 《World Journal of Gastroenterology》 SCIE CAS 2019年第36期5559-5568,共10页
BACKGROUND Small-for-size grafts (SFSGs) in living donor liver transplantation (LDLT) could optimize donor postoperative outcomes and also expand the potential donor pool. Evidence on whether SFSGs would affect medium... BACKGROUND Small-for-size grafts (SFSGs) in living donor liver transplantation (LDLT) could optimize donor postoperative outcomes and also expand the potential donor pool. Evidence on whether SFSGs would affect medium-term and long-term recipient graft survival is lacking. AIM To evaluate the impact of small-for-size liver grafts on medium-term and longterm graft survival in adult to adult LDLT. METHODS A systematic review and meta-analysis were performed by searching eligible studies published before January 24, 2019 on PubMed, EMBASE, and Web of Science databases. The primary outcomes were 3-year and 5-year graft survival. Incidence of small-for-size syndrome and short term mortality were also extracted. RESULTS This meta-analysis is reported according to the guidelines of the PRISMA 2009 Statement. Seven retrospective observational studies with a total of 1821 LDLT recipients were included in the meta-analysis. SFSG is associated with significantly poorer medium-term graft survival. The pooled odds ratio for 3-year graft survival was 1.58 [95% confidence interval 1.10-2.29, P = 0.014]. On the other hand, pooled results of the studies showed that SFSG had no significant discriminatory effect on 5-year graft survival with an odds ratio of 1.31 (95% confidence interval 0.87-1.97, P = 0.199). Furthermore, incidence of small-for-size syndrome detected in recipients of SFSG ranged from 0-11.4% in the included studies. CONCLUSION SFSG is associated with inferior medium-term but not long-term graft survival. Comparable long-term graft survival based on liver graft size shows that smaller grafts could be accepted for LDLT with appropriate flow modulatory measures. Close follow-up for graft function is warranted within 3 years after liver transplantation. 展开更多
关键词 Living DONOR liver TRANSPLANTATION small-for-size GRAFTS small-for-size syndrome GRAFT survival
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Should temporary extracorporeal continuous portal diversion replace meso/porta-caval shunts in “small-for-size” syndrome in porcine hepatectomy? 被引量:3
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作者 Da-Dong Wang Yong Xu +4 位作者 Zi-Man Zhu Xiang-Long Tan Yu-Liang Tu Ming-Ming Han Jing-Wang Tan 《World Journal of Gastroenterology》 SCIE CAS 2015年第3期888-896,共9页
AIM:To investigate the feasibility of temporary extracorporeal continuous porta-caval diversion(ECPD) to relieve portal hyperperfusion in "small-for-size" syndrome following massive hepatectomy in pigs.METHO... AIM:To investigate the feasibility of temporary extracorporeal continuous porta-caval diversion(ECPD) to relieve portal hyperperfusion in "small-for-size" syndrome following massive hepatectomy in pigs.METHODS:Fourteen pigs underwent 85%-90% liver resection and were then randomly divided into thecontrol group(n = 7) and diversion group(n = 7).In the diversion group,portal venous blood was aspirated through the portal catheter and into a tube connected to a centrifugal pump.After filtration,the blood was returned to the pig through a double-lumen catheter inserted into the internal jugular or subclavian vein.With the conversion pump,portal venous inflow was partially diverted to the inferior vena cava through a catheter inserted via the gastroduodenal vein at 100-130 m L/min.Portal hemodynamics,injury,and regeneration in the liver remnant were compared between the two groups.RESULTS:Compared to the control group,porta-caval diversion via ECPD significantly mitigated excessive portal venous flow and portal vein pressure(PVP); the portal vein flow(PVF),hepatic artery flow(HAF),and PVP in the two groups were not significantly different at baseline; however,the PVF(431.8 ± 36.6 vs 238.8 ± 29.3,P < 0.01; 210.3 ± 23.4 vs 122.3 ± 20.6,P < 0.01) and PVP(13.8 ± 2.6 vs 8.7 ± 1.4,P < 0.01; 15.6 ± 2.1 vs 10.1 ± 1.3,P < 0.05) in the control group were significantly higher than those in the diversion group,respectively.The HAF in the control group was significantly lower than that in the diversion group at 2 h and 48 h post hepatectomy,and ECPD significantly attenuated injury to the sinusoidal lining and hepatocytes,increased the regeneration index of the liver remnant,and relieved damage that the liver remnant suffered due to endotoxin and bacterial translocation.CONCLUSION:ECPD,which can dynamically modulate portal inflow,can reduce injury to the liver remnant and facilitate liver regeneration,and therefore should replace permanent meso/porta-caval shunts in "smallfor-size" syndrome. 展开更多
关键词 small-for-size syndrome EXTRACORPOREAL CONTINUOUS
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Small-for-size syndrome in adult-to-adult living-related liver transplantation 被引量:15
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作者 Salvatore Gruttadauria Duilio Pagano +1 位作者 Angelo Luca Bruno Gridelli 《World Journal of Gastroenterology》 SCIE CAS CSCD 2010年第40期5011-5015,共5页
Small-for-size syndrome (SFSS) in adult-to-adult living-related donor liver transplantation (LRLT) remains the greatest limiting factor for the expansion of segmental liver transplantation from either cadaveric or liv... Small-for-size syndrome (SFSS) in adult-to-adult living-related donor liver transplantation (LRLT) remains the greatest limiting factor for the expansion of segmental liver transplantation from either cadaveric or living donors. Portal hyperperfusion, venous pathology, and the arterial buffer response signif icantly contribute to clinical and histopathological manifestations of SFSS. Here, we review the technical aspects of surgical and radiological procedures developed to treat SFSS in LRLT, along with the pathophysiology of this condition. 展开更多
关键词 Adult-to-adult living-related liver transplantation small-for-size syndrome Liver resection Liver transplantation
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Small-for-size syndrome in living donor liver transplantation 被引量:5
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作者 Shintaro Yagi Shinji Uemoto 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2012年第6期570-576,共7页
When the graft volume is too small to satisfy the recipient’s metabolic demand, the recipient may thus experience small-for-size syndrome (SFSS). Because the occurrence of SFSS is determined by not only the liver gra... When the graft volume is too small to satisfy the recipient’s metabolic demand, the recipient may thus experience small-for-size syndrome (SFSS). Because the occurrence of SFSS is determined by not only the liver graft volume but also a combination of multiple negative factors, the definitions of small-for-size graft (SFSG) and SFSS are different in each institute and at each time. In the clinical setting, surgical inflow modulation and maximizing the graft outflow are keys to overcoming SFSS. Accordingly, relatively smaller-sized grafts can be used with surgical modification and pharmacological manipulation targeting portal circulation and liver graft quality. Therefore, the focus of the SFSG issue is now shifting from how to obtain a larger graft from the living donor to how to manage the use of a smaller graft to save the recipient, considering donor safety to be a priority. 展开更多
关键词 living donor liver transplantation small-for-size syndrome
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Extracorporeal continuous portal diversion plus temporal plasmapheresis for “small-for-size” syndrome 被引量:4
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作者 Peng Hou Chao Chen +2 位作者 Yu-Liang Tu Zi-Man Zhu Jing-Wang Tan 《World Journal of Gastroenterology》 SCIE CAS 2013年第33期5464-5472,共9页
AIM:To investigate the effect of plasmapheresis via the portal vein for"small-for-size"syndrome(SFSS)aided by extracorporeal continuous portal diversion(ECPD).METHODS:Extensive or total hepatectomy in the pi... AIM:To investigate the effect of plasmapheresis via the portal vein for"small-for-size"syndrome(SFSS)aided by extracorporeal continuous portal diversion(ECPD).METHODS:Extensive or total hepatectomy in the pig is usually adopted as a postoperative liver failure(PLF)or SFSS model.In this study,animals which underwent85%-90%hepatectomy were randomized into either the Systemic group(n=7)or the Portal group(n=7).In the Systemic group,all pigs received temporal plasmapheresis(PP)via the extracorporeal catheter circuit(systemic to systemic circulation)from 24 to 30 h posthepatectomy(PH);in the Portal group,all pigs received ECPD to divert partial portal vein flow(PVF)to the systemic circulation after hepatectomy,then converted to temporal PP from 24 to 30 h PH,and subsequently converted to ECPD again until 48 h PH.In the Portal group,the PVF was preserved at 3.0-3.3 times that of the baseline value,similar to that following 70%hepatectomy,which was regarded as the optimal PVF to the hypertrophic liver remnant.At 48 h PH,all pigs were re-opened and the portal vein pressure(PVP),PVF,and HAF(hepatic artery flow)were measured,and then diversion of the portal venous flow was terminated.After1 h the PVP,PVF,and HAF were re-measured.The portal hemodynamic changes,liver injury,liver regeneration and bacterial/lipopolysaccharide(LPS)translocation were evaluated in the two groups.RESULTS:The PVP in the Portal group was significantly lower than that in the Systemic group during the time period from 2 to 49 h PH(P<0.05).Serum alanine aminotransferase(ALT),total bilirubin(TB)and ammonia were significantly reduced in the Portal group compared with the Systemic group from 24 to 48 h PH(P<0.05).The Portal group may have attenuated sinusoidal endothelial injury and decreased the level of HA compared with the Systemic group.In the Systemic group,there was significant sinusoidal dilation,hydropic changes in hepatocytes and hemorrhage into the hepatic parenchyma,and the sinusoidal endothelial lining was partially destroyed and detached into the sinusoidal space.CD31immunostaining revealed significant destruction of the endothelial lining.In the Portal group,there was no intraparenchymal hemorrhage and the sinusoidal endothelial cells and hepatocytes were well preserved.CD31immunostaining was mild which indicated less destruction of the endothelial lining.HA was significantly decreased in the Portal group compared with the Systemic group from 2 to 48 h PH.The rate of liver remnant regeneration was elevated,while apoptosis was attenuated in the Portal group compared with the Systemic group.Thymidine kinase activity was much higher in the Portal group than in the Systemic group at 48 h PH.The PCNA index was significantly increased and the apoptotic index was significantly decreased in the Portal group compared with the Systemic group.Bacterial translocation and endotoxin,as well as the inflammatory response,were significantly attenuated in the Portal group compared with the Systemic group.LPS,tumor necrosis factor-and interleukin-6 levels were all significantly decreased in the Portal group compared with the Systemic group from 24 to48 h PH,while bacterial DNA level was significantly decreased from 2 to 48 h PH.CONCLUSION:PP plus ECPD via the portal vein can attenuate toxic load and hyperperfusion injury,and should be undertaken instead of PP via the systemic circulation in SFSS or PLF. 展开更多
关键词 small-for-size syndrome POSTOPERATIVE liver failure EXTRACORPOREAL PORTAL DIVERSION PLASMAPHERESIS HEPATECTOMY
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Extended hepatectomy with segments Ⅰand Ⅶ as resection remnant:a simple model for small-for-size injuries in pigs 被引量:3
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作者 Qiang Xia,Tian-Fei Lu,Zhi-Hua Zhou,Ling-Xiang Hu,Jun Ying,De-Zhong Ding, Xiao-Song Chen and Jian-Jun Zhang Transplantation Center and Department of Clinical Laboratory ,Renji Hospital,School of Medicine,Shanghai Jiaotong University,Shanghai 200127,China Tyco Clinical Institute,Shanghai 200040,China 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2008年第6期601-607,共7页
BACKGROUND:Small-for-size(SFS)syndrome is an important clinical problem after living donor liver transplantation,split liver transplantation or extended hepatectomy.The uncertainty of the mechanisms and treatments of ... BACKGROUND:Small-for-size(SFS)syndrome is an important clinical problem after living donor liver transplantation,split liver transplantation or extended hepatectomy.The uncertainty of the mechanisms and treatments of SFS syndrome urges surgeons to establish effective models for SFS syndrome. METHODS:A new porcine model for SFS syndrome based on extended hepatectomy was established.Portal pressure gradient was observed before and after the surgery,and venous sampling for estimation of alanine aminotransferase, total bilirubin,and international normalized ratio was continued on a daily basis. RESULTS:Although the external morphology of the porcine liver differs from that of human being,segmental anatomy is remarkably similar in term of its vascularity and biliary tree.Extended hepatectomy with segmentsⅠand Ⅶas resection remnant(about 20%of total liver volume) resulted in similar survival rates,blood liver function tests,and elevated portal pressure gradient as clinical SFS syndrome. CONCLUSIONS:The extended hepatectomy based new model can easily be reproduced,with few costs and surgical complications.Clinical SFS syndrome can easily be simulated by this new model,which is a useful tool for studying SFS syndrome-related liver injuries,especially portal overperfusion and hypertension. 展开更多
关键词 HEPATECTOMY small-for-size syndrome
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Expression of iNOS in early injury in a rat model of small-for-size liver transplantation 被引量:5
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作者 Jiang, Wei-Wei Kong, Lian-Bao +1 位作者 Li, Guo-Qiang Wang, Xue-Hao 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2009年第2期146-151,共6页
BACKGROUND: Living donor liver transplantation has been widely accepted as the treatment of choice for end-stage liver disease. Large amounts of nitric oxide generated by inducible nitric oxide synthase (iNOS) have be... BACKGROUND: Living donor liver transplantation has been widely accepted as the treatment of choice for end-stage liver disease. Large amounts of nitric oxide generated by inducible nitric oxide synthase (iNOS) have been shown to play an important role in many inflammatory and immune reactions, but expression of iNOS in small-for-size liver transplantation is unknown. The aims of this study were to determine the time course of iNOS mRNA and protein as well as the redox state of liver biopsies in a rat model of small-for-size liver transplantation. METHODS: Male Sprague-Dawley rats were divided into a control group, a warm ischemia-reperfusion (IR) group, and a small-for-size liver graft group. Real-time RT-PCR and Western blotting were used to characterize the time course of the expression of iNOS mRNA and protein, respectively. Malondialdehyde (MDA) and superoxide dismutase (SOD) were used as markers to characterize the redox state of liver tissues, and the time courses of MDA and SOD levels were also measured. RESULTS: The expression of iNOS mRNA and protein levels in the warm IR and small-for-size graft groups both significantly increased after reperfusion, and peaked at 3 hours. Moreover, the increase in MDA was accompanied by increased iNOS in the period of 1-24 hours after reperfusion. The MDA levels in the warm IR and small-for-size graft groups significantly increased after reperfusion, peaked at 3 hours, and decreased thereafter. The direction of change in SOD was opposite that of the change in MDA. CONCLUSIONS: The expression of iNOS mRNA and protein is activated after reperfusion both in hepatic warm IR injury and small-for-size liver graft. Furthermore, the results of this study suggest that iNOS contributes to the damage in warm IR injury and small-for-size grafts via free oxygen radicals. 展开更多
关键词 inducible nitric oxide synthase small-for-size graft ischemia-reperfusion injury liver transplantation
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Industrial Preparation and Acid Resistance of Ultra-stable Y Zeolite with Small Cell Size Produced by Gas-phase Method 被引量:1
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作者 Zhang Jing Jia Jishun +4 位作者 Sha Hao Lu Guanqun Yan Jiasong Wang Shengji Zhou Lingping 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2022年第2期85-90,共6页
Small-cell HSY-S zeolite prepared by the gas-phase ultra-stable method had been researched and developed,and industrial preparation tests of HSY-S have been successfully carried out for the first time.The acid resista... Small-cell HSY-S zeolite prepared by the gas-phase ultra-stable method had been researched and developed,and industrial preparation tests of HSY-S have been successfully carried out for the first time.The acid resistance of industrially prepared HSY-S was investigated by acid solutions with different pH values.The structures and properties of HSY-S and its acid-treated samples were characterized by XRD,XRF,BET,and IR.Results show that the HSY-S samples have the characteristics of high crystallinity,good stability,large specific surface area,and good acid resistance. 展开更多
关键词 zeolite small unit cell size gas-phase ultra-stable acid resistance industrial preparation
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