This paper presents a binary gravitational search algorithm (BGSA) is applied to solve the problem of optimal allotment of DG sets and Shunt capacitors in radial distribution systems. The problem is formulated as a no...This paper presents a binary gravitational search algorithm (BGSA) is applied to solve the problem of optimal allotment of DG sets and Shunt capacitors in radial distribution systems. The problem is formulated as a nonlinear constrained single-objective optimization problem where the total line loss (TLL) and the total voltage deviations (TVD) are to be minimized separately by incorporating optimal placement of DG units and shunt capacitors with constraints which include limits on voltage, sizes of installed capacitors and DG. This BGSA is applied on the balanced IEEE 10 Bus distribution network and the results are compared with conventional binary particle swarm optimization.展开更多
Hepatic myelopathy is a complication seen in patients with chronic liver failure with physiologic or iatrogenic portosystemic shunting. The main symptom is progressive lower limb dyskinesia. The role of the brain moto...Hepatic myelopathy is a complication seen in patients with chronic liver failure with physiologic or iatrogenic portosystemic shunting. The main symptom is progressive lower limb dyskinesia. The role of the brain motor control center in hepatic myelopathy is unknown. This study aimed to investigate the gray matter changes in patients with hepatic myelopathy secondary to transjugular intrahepatic portosystemic shunt and to examine their clinical relevance. This was a cross-sectional study. Twenty-three liver failure patients with hepatic myelopathy(hepatic myelopathy group), 23 liver failure patients without hepatic myelopathy(non-hepatic myelopathy group) after transjugular intrahepatic portosystemic shunt, and 23 demographically matched healthy volunteers were enrolled from March 2014 to November 2016 at Xijing Hospital, Air Force Military Medical University(Fourth Military Medical University), China. High-resolution magnetization-prepared rapid gradient-echo brain imaging was acquired. Group differences in regional gray matter were assessed using voxel-based morphometry analysis. The relationship between aberrant gray matter and motor characteristics was investigated. Results demonstrated that compared with the non-hepatic myelopathy group, gray matter volume abnormalities were asymmetric, with decreased volume in the left insula(P = 0.003), left thalamus(P = 0.029), left superior frontal gyrus(P = 0.006), and right middle cingulate cortex(P = 0.021), and increased volume in the right caudate nucleus(P = 0.017), corrected with open-source software. The volume of the right caudate nucleus in the hepatic myelopathy group negatively correlated with the lower limb clinical rating of the Fugl-Meyer Assessment(r = –0.53, P = 0.01). Compared with healthy controls, patients with and without hepatic myelopathy exhibited overall increased gray matter volume in both thalami, and decreased gray matter volume in both putamen, as well as in the globus pallidus, cerebellum, and vermis. The gray matter abnormalities we found predominantly involved motor-related regions, and may be associated with motor dysfunction. An enlarged right caudate nucleus might help to predict weak lower limb motor performance in patients with preclinical hepatic myelopathy after transjugular intrahepatic portosystemic shunt. This study was approved by the Ethics Committee of Xijing Hospital, Air Force Military Medical University(Fourth Military Medical University), China(approval No. 20140227-6) on February 27, 2014.展开更多
The temperature effects on the electrical performance of a large area multicrystalline silicon solar cell with back-contact technology have been studied in a desert area under ambient conditions using the current shun...The temperature effects on the electrical performance of a large area multicrystalline silicon solar cell with back-contact technology have been studied in a desert area under ambient conditions using the current shunt measuring technique. Therefore, most of the problems encountered with traditional measuring techniques are avoided. The temperature dependency of the current shunt from 5oC up to 50oC has been investigated. Its temperature coefficient proves to be negligible which means that the temperature dependency of the solar cell is completely independent of the current shunt. The solar module installed in a tilted position at the optimum angle of the location, has been tested in two different seasons (winter and summer). The obtained solar cell short circuit current, open circuit voltage and output power are correlated with the measured incident radiation in both seasons and all results are discussed.展开更多
BACKGROUND Portal hypertension(PH)is a major complication of chronic liver disease and a leading cause of mortality and morbidity in patients with cirrhosis.Transjugular intrahepatic portosystemic shunt(TIPS)is an est...BACKGROUND Portal hypertension(PH)is a major complication of chronic liver disease and a leading cause of mortality and morbidity in patients with cirrhosis.Transjugular intrahepatic portosystemic shunt(TIPS)is an established treatment for PH-related complications,including refractory ascites,variceal bleeding,hepatic hydrothorax and Budd-Chiari syndrome.However,post-TIPS cardiac decompensation has been reported in up to 25%of patients,often due to haemodynamic shifts revealing occult cardiac dysfunction.Current approaches to pre-procedural cardiac assessment and risk stratification remain inconsistent.This systematic review examines current recommendations and emerging strategies for cardiovascular evaluation in patients with cirrhosis prior to a TIPS.AIM To identify the key predictive factors for cardiac decompensation following a TIPS in patients with cirrhosis.METHODS A systematic review of available literature,using PubMed(including MEDLINE),Embase and Cochrane databases.Results were searched comprehensively,without exclusion criteria,from inception to May 2025.Given the predominance of retrospective cohort studies,risk of bias assessment was primarily performed using the ROBINS-E tool.RESULTS Thirteen studies were included(n=1674 patients),with a pulled mean decompensation rate of 8.8%.Due to the variability in TIPS timing,study quality and heterogeneity,a meta-analysis was not feasible,therefore results were synthesised narratively.Multiple diastolic dysfunction parameters independently and integrated through the American Society of Echocardiography guidelines demonstrated predictive value.Newly validated risk score,heart failure with preserved ejection fraction,and biomarkers such as N-terminal pro-B-type natriuretic peptide≥125 pg/mL consistently highlight cardiac dysfunction amongst the literature.Our review also explored left-atrial strain imaging as well as recent advances in cardiac magnetic resonance imaging and potential genetic contributors.CONCLUSION Multiple predictors of cardiac decompensation following TIPS exist,however studies are of limited quality.Implementing reliable markers may enable early risk stratification,candidate selection and guide pre-procedural optimisation.展开更多
BACKGROUND Hepatic encephalopathy(HE)is a poorly understood complication in hepatosplenic schistosomiasis(HSS),a neglected cause of non-cirrhotic portal hypertension.Although portosystemic shunts(PSS)are commonly obse...BACKGROUND Hepatic encephalopathy(HE)is a poorly understood complication in hepatosplenic schistosomiasis(HSS),a neglected cause of non-cirrhotic portal hypertension.Although portosystemic shunts(PSS)are commonly observed in HSS patients,the prevalence and clinical impact of overt HE(OHE)and minimal HE(MHE)remain understudied,particularly in resource-limited settings.AIM To determine OHE/MHE prevalence in HSS and its associations with PSS,clinical,and laboratory characteristics.METHODS This cross-sectional study included 200 HSS patients undergoing treatment at the Hospital of Universidade Federal de Pernambuco in Brazil between 2021 and 2023.Cognitive function was assessed using the animal naming test(ANT)and Mini-Mental State Examination(MMSE),while psychological status was evaluated with the Hospital Anxiety and Depression Scale.PSS was identified via ultrasound,and fibrosis severity was quantified using the Coutinho index(CI).Analyses were adjusted for education level and the presence of comorbidities.Statistical analyses were performed using R software.RESULTS The prevalence of OHE was 0.5%,while MHE,diagnosed via ANT,affected 24%of patients.ANT positivity was significantly associated with the presence of PSS(35.1%vs 15.1%;P=0.0018)and higher CI scores(1.79±0.26 vs 1.30±0.84;P=0.045).Patients with MHE demonstrated notably lower MMSE scores(24.06±1.17 vs 26.04±0.63;P=0.0003),independent of education level.The ANT showed high diagnostic robustness,even among patients with limited formal education.CONCLUSION MHE is prevalent in HSS,especially with PSS,and is associated with portal hypertension severity.The ANT enables practical screening,underscoring the need for routine assessment to improve outcomes.展开更多
In this paper, a new technique using a Current Shunt and a Micropotentiometer has been used to study the electrical performance of a large area multicrystalline silicon solar cell at outdoor conditions. The electrical...In this paper, a new technique using a Current Shunt and a Micropotentiometer has been used to study the electrical performance of a large area multicrystalline silicon solar cell at outdoor conditions. The electrical performance is mainly described by measuring both cell short circuit current and open circuit voltage. The measurements of this cell by using multimeters suffer from some problems because the cell has high current intensity with low output voltage. So, the solar cell short circuit current values are obtained by measuring the voltage developed across a known resistance Current Shunt. Samples of the obtained current values are accurately calibrated by using a Micropotentiometer (μpot) thermal element (TE) to validate this new measuring technique. Moreover, the solar cell open circuit voltage has been measured. Besides, the cell output power has been calculated and can be correlated with the measured incident radiation.展开更多
Spontaneous porto-systemic shunts(SPSS)are frequent in liver cirrhosis and their prevalence increases as liver function deteriorates,probably as a consequence of worsening portal hypertension,but without achieving an ...Spontaneous porto-systemic shunts(SPSS)are frequent in liver cirrhosis and their prevalence increases as liver function deteriorates,probably as a consequence of worsening portal hypertension,but without achieving an effective protection against cirrhosis'complications.Several types of SPSS have been described in the literature,each one associated with different clinical manifestations.In particular,recurrent or persistent hepatic encephalopathy is more frequent in patients with splenorenal shunt,while the presence of gastric varices and consequently the incidence of variceal bleeding is more common in gastrorenal shunt.In the advanced stage,the presence of large SPSS can lead to the so called“portosystemic shunt syndrome”,characterized by a progressive deterioration of hepatic function,hepatic encephalopathy and,sometimes,portal vein thrombosis.The detection of SPSS in patients with liver cirrhosis is recommended in order to prevent or treat recurrent hepatic encephalopathy or variceal bleeding.展开更多
BACKGROUND Duodenal varices are a lesser-known complication with non-cirrhotic portal hypertension. We report a circuitous route from missed diagnosis of duodenal varices to correction. An extremely rare case of duode...BACKGROUND Duodenal varices are a lesser-known complication with non-cirrhotic portal hypertension. We report a circuitous route from missed diagnosis of duodenal varices to correction. An extremely rare case of duodenal variceal bleeding secondary to idiopathic portal hypertension(IPH) is expounded in this study, which was controlled by transjugular intra-hepatic porto-systemic shunt(TIPS) plus embolization. CASE SUMMARY A 46-year-old woman with anemia for two years was frequently admitted to the local hospital. Upon examination, anemia was attributed to gastrointestinal tract bleeding, which resulted from duodenal variceal bleeding detected by repeated esophagogastroduodenoscopy. At the end of a complete workup, IPH leadingto duodenal varices was diagnosed. Portal venography revealed that the remarked duodenal varices originated from the proximal superior mesenteric vein. TIPS plus embolization with coils and Histoacryl was performed to obliterate the rupture of duodenal varices. The anemia resolved, and the duodenal varices completely vanished by 2 mo after the initial operation. CONCLUSION TIPS plus embolization may be more appropriate to treat the bleeding of large duodenal varices.展开更多
Delayed liver laceration following transjugular intrahepatic portosystemic shunt (TIPS) is a serious and likely underdiagnosed complication. It is however an important complication following TIPS, which remains one of...Delayed liver laceration following transjugular intrahepatic portosystemic shunt (TIPS) is a serious and likely underdiagnosed complication. It is however an important complication following TIPS, which remains one of the most technically challenging interventional procedures performed. In addition to laceration, a number of complications regarding bleeding and perforation are well described following TIPS procedures. We feel the adoption of techniques such as ours and that of other authors described in the literature using an ultrasoundguided percutaneous transhepatic approach with a small caliber needle provides a safer and less traumatic procedure and should reduce complications of bleeding and almost completely eliminate the risk of liver laceration. Our procedure was successfully performed under conscious sedation rather than general anaesthesia further reducing the overall procedural risk to the patient.展开更多
Gastric antral vascular ectasia(GAVE) may cause gastrointestinal bleeding(GIB). The treatment of GAVE relies on endoscopic approaches such as electrocoagulation(argon plasma coagulation, laser therapy, heater probe th...Gastric antral vascular ectasia(GAVE) may cause gastrointestinal bleeding(GIB). The treatment of GAVE relies on endoscopic approaches such as electrocoagulation(argon plasma coagulation, laser therapy, heater probe therapy, radiofrequency ablation), cryotherapy, and band ligation. In refractory cases, antrectomy may be considered. In the event of an associated cirrhosis and portal hypertension, it has been suggested that antrectomy could be an option, provided the mortality risk isn't considered too great. We report the case of a 67-year-old cirrhotic patient who presented with GAVE related GIB, unresponsive to multiple endoscopic treatments. The patient had a good liver function(model for end-stage disease 10). After a multidisciplinary meeting, a transjugular intrahepatic portosystemic shunt(TIPS) procedure was performed, in order to treat the cirrhosis associated ascites. The outcome was successful. An antrectomy was then performed, with no recurrence of GIB and no transfusion need during three months of follow up. In this case, the TIPS procedure achieved a complete ascites regression, allowing a safer surgical treatment of the GAVE-related GIB.展开更多
The open-circuit fault of the power switches in shunt active power filter(SAPF) would exacerbate the harmonic pollution of power grid, and degrade the reliability of the devices and system. A fault diagnosis method is...The open-circuit fault of the power switches in shunt active power filter(SAPF) would exacerbate the harmonic pollution of power grid, and degrade the reliability of the devices and system. A fault diagnosis method is proposed based on reference model and an over-modulation strategy under hardware fault tolerance for SAPF. First, a mathematic model is established for SAPF. Second, the residuals are generated by comparing the outputs of reference model and those of actual model, and open-switch fault is detected and diagnosed by residual evaluation. After that, hardware fault tolerance is performed with the three-phase four-switch(TPFS) topology to isolate the faulty phase. Finally, the over-modulation strategy is proposed to increase the voltage transfer ratio of the TPFS topology. Simulation and experimental results verified the feasibility and effectiveness of the proposed method.展开更多
This paper proposes the evaluation of arteriovenous shunt (AVS) stenosis using a fractional-order Fuzzy Petri net based screening system for long-term hemodialysis treatment of patients. The screening system uses the ...This paper proposes the evaluation of arteriovenous shunt (AVS) stenosis using a fractional-order Fuzzy Petri net based screening system for long-term hemodialysis treatment of patients. The screening system uses the Burg method, the fractional-order chaos system, and the Fuzzy Petri net (FPN) for early detection of AVS dysfunction. The Burg method is an autoregressive (AR) model that is used to estimate the frequency spectra of a phonoangiographic signal and to identify the spectral peaks in the region from 25 Hz to 800 Hz. In AVS, the frequency spectrum varies between normal blood flow and turbulent flow. The power spectra demonstrate changes in frequency and amplitude as the degree of stenosis changes. A screening system combining fractional-order chaos system and FPN is used to track the differences in the frequency spectra between the normal and stenosis access. The dynamic errors are indexes that can be used to evaluate the degree of AVS stenosis using a FPN. For 42 long-term follow-up patients, testing results show that the proposed screening system is more efficient in the evaluation of AVS stenosis.展开更多
BACKGROUND There is a close relationship between cirrhosis and hepatocellular carcinoma(HCC).Transjugular intrahepatic portosystemic shunt(TIPS)has good clinical effect in treating the complication of portal hypertens...BACKGROUND There is a close relationship between cirrhosis and hepatocellular carcinoma(HCC).Transjugular intrahepatic portosystemic shunt(TIPS)has good clinical effect in treating the complication of portal hypertension.However,because of the risk of postoperative liver failure,severe complications,and low survival rate for HCC,TIPS is contraindicated in patients with portal hypertension and liver cancer.We studied a large cohort of patients with cirrhosis and HCC who underwent TIPS for recurrent variceal bleeding and/or ascites.AIM To assess the safety,efficacy,and survival rate in patients with HCC who underwent TIPS.ME THODS Group A comprised 217 patients with HCC and portal hypertension who underwent the TIPS procedure between 1999 and 2014.After TIPS deployment,these patients received palliative treatment for HCC.Group B comprised a cohort of 136 HCC patients with portal hypertension who did not undergo TIPS placement.Group B received palliative treatment for HCC plus medical therapy for portal hypertension.The clinical outcomes and survival rate were assessed.RES UL TS In Group A,the primary technical success rate was 97.69%for TIPS placement,and no severe procedure-related complications of TIPS placement were reported.The control of variceal bleeding(VB)within 1 mo did not differ significantly between the groups(P=0.261).Absorption of refractory ascites within 1 mo,recurrence of VB,and recurrence of refractory ascites differed significantly between the groups(P=0.017,0.023,and 0.009,respectively).By comparison,the rate of hepatic encephalopathy in Group B was lower than that in Group A(P=0.036).The 1-,2-,3-,4-,and 5-year survival rates were significantly different between Groups A and B(X2=12.227,P=0.018;X2=12.457,P=0.014;X2=26.490,P=0.013;X2=21.956,P=0.009,and X2=24.596,P=0.006,respectively).The mean survival time was 43.7 mo in Group A and 31.8 mo in Group B.Median survival time was 50.0 mo in Group A and 33.0 mo in Group B.Mean and median survival differed significantly between the two groups(P=0.000,X2=35.605,log-rank test).The mortality rate from VB in Group A was higher than that in Group B(P=0.006),but the rates of hepatic tumor,hepatic failure,and multiorgan failure did not differ significantly between the two groups(P=0.173,0.246 and 0.257,respectively).CONCLUSION TIPS combined with palliative treatment is safe and effective for portal hypertension in patients with HCC.展开更多
BACKGROUND Main portal vein tumor thrombus(MPVTT), which has a high incidence, is the major complication of terminal liver cancer. The occurrence of MPVTT is always a negative prognostic factor for patients with hepat...BACKGROUND Main portal vein tumor thrombus(MPVTT), which has a high incidence, is the major complication of terminal liver cancer. The occurrence of MPVTT is always a negative prognostic factor for patients with hepatocellular carcinoma(HCC).Therefore, attention should be paid to the treatment of MPVTT and its complications.AIM To evaluate the efficacy of transarterial chemoembolization/transarterial embolization(TACE/TAE)+^(125)I seeds implantation with transjugular intrahepatic portosystemic shunt(TIPS) in treating MPVTT and its complications.METHODS From January 2007 to March 2015, 85 consecutive patients with MPVTT were nonrandomly assigned to undergo treatment with TACE/TAE + TIPS and ^(125)I implantation(TIPS-^(125)I group) or TACE/TAE + TIPS only(TIPS only group) in Beijing Shijitan Hospital, and all clinical data were collected. During 24 mo follow-up, the incidence of overall survival, stent stenosis and symptom recurrence was analyzed to evaluate the efficacy of TIPS-^(125)I.RESULTS During 24 mo follow-up of all patients, we collected data at 6, 12 and 24 mo. The rates of survival were 80%, 45%, and 20%, respectively, in the TIPS-^(125)I group,whereas those in the TIPS only group were 64.4%, 24.4%, and 4.4%, respectively(P < 0.05). The rates of symptom recurrence were 7.5%, 22.5%, and 35%,respectively, in the TIPS-^(125)I group, whereas those in the TIPS only group were31.1%, 62.2%, and 82.2%(P < 0.05). The rates of stent restenosis were 12.5%,27.5%, and 42.5%, respectively, in the TIPS-^(125)I group, and 42.2%, 68.9%, and84.4%, respectively, in the TIPS only group(P < 0.05). TIPS-^(125)I was found to be significantly favorable in treating MPVTT and its complications in patients with HCC.CONCLUSION TACE/TAE+^(125)I combined with TIPS is effective in treating MPVTT and its complications, improving quality of life of patients and reducing mortality.展开更多
Transjugular intrahepatic portosystemic shunt (TIPSS) is considered a valid therapeutic option for the treatment of portal hypertension and its complications.The guidelines for this procedure have already been establi...Transjugular intrahepatic portosystemic shunt (TIPSS) is considered a valid therapeutic option for the treatment of portal hypertension and its complications.The guidelines for this procedure have already been established on the basis of the normal vascular anatomy and of various technical radiological aspects.In some few rare cases,diagnosis of a congenital vascular anomaly can be made accidentally by interventional radiologists,making the procedure of the TIPSS placement extremely difficult or in some cases technically impossible.This report describes a rare vascular malformation characterized by the absence of the right superior vena cava and persistence of the left superior vena cava in a patient with a diagnosis of advanced liver cirrhosis who needed a TIPSS placement in order to control refractory ascites.展开更多
The present study was aimed at dynamic observation of the ef fects of end to side portacaval shunt (PCS) and end to side mesocaval shunt (MCS) in dogs on the functions of the liver and pancreatic islet cells. Accordin...The present study was aimed at dynamic observation of the ef fects of end to side portacaval shunt (PCS) and end to side mesocaval shunt (MCS) in dogs on the functions of the liver and pancreatic islet cells. According to correlation between the changes of plasma insulin level in the portal vein and hepatic flow and liver morphology after PCS and MCS, we conclude that the depletion of hepatic flow is the major factor in the deterioration of liver functions. The levels of insulin and glucagon in both the peripheral vein and the portal vein were decreased after PCS and MCS. There was also depletion of pancreatic islet A and B cells and vacuolar degeneration of the pancreas. These changes were more signifcant in PCS than in MCS, suggesting that portasystemic shunt, especially total portasystemie shunt, might damage pancreatic endocrine functions.展开更多
AIM: To evaluate the clinical effects of transjugular intrahepatic portosystemic shunt (TIPS) vs endoscopic variceal sclerotherapy (EVS) in the management of gastric variceal (GV) bleeding in terms of variceal rebleed...AIM: To evaluate the clinical effects of transjugular intrahepatic portosystemic shunt (TIPS) vs endoscopic variceal sclerotherapy (EVS) in the management of gastric variceal (GV) bleeding in terms of variceal rebleeding, hepatic encephalopathy (HE), and survival by meta-analysis.METHODS: Medline, Embase, and CNKI were searched. Studies compared TIPS with EVS in treating GV bleeding were identified and included according to our predefined inclusion criteria. Data were extracted independently by two of our authors. Studies with prospective randomized design were considered to be of high quality. Hazard ratios (HRs) or odd ratios(ORs) were calculated using a fixed-effects model when there was no inter-trial heterogeneity. Oppositely, a random-effects model was employed.RESULTS: Three studies with 220 patients who had at least one episode of GV bleeding were included in the present meta-analysis. The proportions of patients with viral cirrhosis and alcoholic cirrhosis were 39% (range 0%-78%) and 36% (range 12% to 41%), respectively. The pooled incidence of variceal rebleeding in the TIPS group was significantly lower than that in the EVS group (HR = 0.3, 0.35, 95% CI: 0.17-0.71, P = 0.004). However, the risk of the development of any degree of HE was significantly increased in the TIPS group (OR = 15.97, 95% CI: 3.61-70.68). The pooled HR of survival was 1.26(95% CI: 0.76-2.09, P = 0.36). No inter-trial heterogeneity was observed among these analyses. CONCLUSION: The improved effect of TIPS in the prevention of GV rebleeding is associated with an increased risk of HE. There is no survival difference between the TIPS and EVS groups. Further studies are needed to evaluate the survival benefit of TIPS in cirrhotic patients with GV bleeding.展开更多
In the present study we observed dynamically and systemically the changes of plasma somatostatin and glucagon in the peripheral and portal vein, and the changes of pancreatic immunopathology in the course of developme...In the present study we observed dynamically and systemically the changes of plasma somatostatin and glucagon in the peripheral and portal vein, and the changes of pancreatic immunopathology in the course of development of cirrhosis induced by CCl<sub>4</sub> and after portacaval shunt （PCS） in the cirrhotic rats as well as investigated their causes and correlationship. The results showed that hyperglucagonemia was caused by spontaneous portosystemic shunting and surgically induced portacaval anastomosis. Moreover, there was much higher level of glucagon in the portal vein with corresponding increase of A cells in PCS rats than those in the controls, indicating that another cause for elevation of glucagon was hypersecretion of pancreatic A cells. Our data demonstrated that both deterioration of liver function and portosystemic shunting might not be responsible for the elevated level of somatostatin in the cirrhotic rats with PCS. However, there was a closed positive correlation between plasma glucagon and somatostatin. Thus it was concluded that hyperglucagonemia stimulated the release of somatostatin. In view of the fact the elevated level of glucagon was much higher than that of somatostatin, there was probably a relative lack of somatostatin in cirrhosis with portal hypertension.展开更多
This paper presents a fuzzy logic based three phase four wire four-leg shunt active power filter to suppress harmonic currents. Modified instantaneous p-q theory is adopted for calculating the compensating current. Fu...This paper presents a fuzzy logic based three phase four wire four-leg shunt active power filter to suppress harmonic currents. Modified instantaneous p-q theory is adopted for calculating the compensating current. Fuzzy-adaptive hysteresis band technique is applied for the current control to derive the switching signals for the voltage source inverter. A fuzzy logic controller is developed to control the voltage of the DC capacitor. Computer simulations are carried out on a sample power system to demonstrate the suitability of the proposed control strategy, for harmonic reduction under three different conditions namely, ideal, unbalance, unbalance and distorted source voltage conditions. The proposed control strategy is found to be effective to reduce the harmonics and compensate reactive power and neutral current and balance load currents under ideal and non-ideal source voltage conditions.展开更多
As more and more variable frequency drives (VFDs), electronic ballasts, battery chargers, and static Var compensators are installed in facilities, the problems related to harmonics are expected to get worse. As a resu...As more and more variable frequency drives (VFDs), electronic ballasts, battery chargers, and static Var compensators are installed in facilities, the problems related to harmonics are expected to get worse. As a result Active power filter (APF) gains much more attention due to excellent harmonic compensation. But still the performance of the active filter seems to be in contradictions with different control strategies. This paper presents detailed analysis to compare and elevate the performance of two control strategies for ex-tracting reference currents of shunt active filters under balanced, un-balanced and non-sinusoidal conditions by using Fuzzy controller. The well known methods, instantaneous real active and reactive power method (p-q) and active and reactive current method (id-iq) are two control methods which are extensively used in active filters. Extensive Simulations are carried out with fuzzy controller for both p-q and Id-Iq methods for different voltage conditions and adequate results were presented. Simulation results validate the superior per-formance of active and reactive current control strategy (id-iq) with fuzzy controller over active and reactive power control strategy (p-q) with fuzzy controller.展开更多
文摘This paper presents a binary gravitational search algorithm (BGSA) is applied to solve the problem of optimal allotment of DG sets and Shunt capacitors in radial distribution systems. The problem is formulated as a nonlinear constrained single-objective optimization problem where the total line loss (TLL) and the total voltage deviations (TVD) are to be minimized separately by incorporating optimal placement of DG units and shunt capacitors with constraints which include limits on voltage, sizes of installed capacitors and DG. This BGSA is applied on the balanced IEEE 10 Bus distribution network and the results are compared with conventional binary particle swarm optimization.
文摘Hepatic myelopathy is a complication seen in patients with chronic liver failure with physiologic or iatrogenic portosystemic shunting. The main symptom is progressive lower limb dyskinesia. The role of the brain motor control center in hepatic myelopathy is unknown. This study aimed to investigate the gray matter changes in patients with hepatic myelopathy secondary to transjugular intrahepatic portosystemic shunt and to examine their clinical relevance. This was a cross-sectional study. Twenty-three liver failure patients with hepatic myelopathy(hepatic myelopathy group), 23 liver failure patients without hepatic myelopathy(non-hepatic myelopathy group) after transjugular intrahepatic portosystemic shunt, and 23 demographically matched healthy volunteers were enrolled from March 2014 to November 2016 at Xijing Hospital, Air Force Military Medical University(Fourth Military Medical University), China. High-resolution magnetization-prepared rapid gradient-echo brain imaging was acquired. Group differences in regional gray matter were assessed using voxel-based morphometry analysis. The relationship between aberrant gray matter and motor characteristics was investigated. Results demonstrated that compared with the non-hepatic myelopathy group, gray matter volume abnormalities were asymmetric, with decreased volume in the left insula(P = 0.003), left thalamus(P = 0.029), left superior frontal gyrus(P = 0.006), and right middle cingulate cortex(P = 0.021), and increased volume in the right caudate nucleus(P = 0.017), corrected with open-source software. The volume of the right caudate nucleus in the hepatic myelopathy group negatively correlated with the lower limb clinical rating of the Fugl-Meyer Assessment(r = –0.53, P = 0.01). Compared with healthy controls, patients with and without hepatic myelopathy exhibited overall increased gray matter volume in both thalami, and decreased gray matter volume in both putamen, as well as in the globus pallidus, cerebellum, and vermis. The gray matter abnormalities we found predominantly involved motor-related regions, and may be associated with motor dysfunction. An enlarged right caudate nucleus might help to predict weak lower limb motor performance in patients with preclinical hepatic myelopathy after transjugular intrahepatic portosystemic shunt. This study was approved by the Ethics Committee of Xijing Hospital, Air Force Military Medical University(Fourth Military Medical University), China(approval No. 20140227-6) on February 27, 2014.
文摘The temperature effects on the electrical performance of a large area multicrystalline silicon solar cell with back-contact technology have been studied in a desert area under ambient conditions using the current shunt measuring technique. Therefore, most of the problems encountered with traditional measuring techniques are avoided. The temperature dependency of the current shunt from 5oC up to 50oC has been investigated. Its temperature coefficient proves to be negligible which means that the temperature dependency of the solar cell is completely independent of the current shunt. The solar module installed in a tilted position at the optimum angle of the location, has been tested in two different seasons (winter and summer). The obtained solar cell short circuit current, open circuit voltage and output power are correlated with the measured incident radiation in both seasons and all results are discussed.
文摘BACKGROUND Portal hypertension(PH)is a major complication of chronic liver disease and a leading cause of mortality and morbidity in patients with cirrhosis.Transjugular intrahepatic portosystemic shunt(TIPS)is an established treatment for PH-related complications,including refractory ascites,variceal bleeding,hepatic hydrothorax and Budd-Chiari syndrome.However,post-TIPS cardiac decompensation has been reported in up to 25%of patients,often due to haemodynamic shifts revealing occult cardiac dysfunction.Current approaches to pre-procedural cardiac assessment and risk stratification remain inconsistent.This systematic review examines current recommendations and emerging strategies for cardiovascular evaluation in patients with cirrhosis prior to a TIPS.AIM To identify the key predictive factors for cardiac decompensation following a TIPS in patients with cirrhosis.METHODS A systematic review of available literature,using PubMed(including MEDLINE),Embase and Cochrane databases.Results were searched comprehensively,without exclusion criteria,from inception to May 2025.Given the predominance of retrospective cohort studies,risk of bias assessment was primarily performed using the ROBINS-E tool.RESULTS Thirteen studies were included(n=1674 patients),with a pulled mean decompensation rate of 8.8%.Due to the variability in TIPS timing,study quality and heterogeneity,a meta-analysis was not feasible,therefore results were synthesised narratively.Multiple diastolic dysfunction parameters independently and integrated through the American Society of Echocardiography guidelines demonstrated predictive value.Newly validated risk score,heart failure with preserved ejection fraction,and biomarkers such as N-terminal pro-B-type natriuretic peptide≥125 pg/mL consistently highlight cardiac dysfunction amongst the literature.Our review also explored left-atrial strain imaging as well as recent advances in cardiac magnetic resonance imaging and potential genetic contributors.CONCLUSION Multiple predictors of cardiac decompensation following TIPS exist,however studies are of limited quality.Implementing reliable markers may enable early risk stratification,candidate selection and guide pre-procedural optimisation.
文摘BACKGROUND Hepatic encephalopathy(HE)is a poorly understood complication in hepatosplenic schistosomiasis(HSS),a neglected cause of non-cirrhotic portal hypertension.Although portosystemic shunts(PSS)are commonly observed in HSS patients,the prevalence and clinical impact of overt HE(OHE)and minimal HE(MHE)remain understudied,particularly in resource-limited settings.AIM To determine OHE/MHE prevalence in HSS and its associations with PSS,clinical,and laboratory characteristics.METHODS This cross-sectional study included 200 HSS patients undergoing treatment at the Hospital of Universidade Federal de Pernambuco in Brazil between 2021 and 2023.Cognitive function was assessed using the animal naming test(ANT)and Mini-Mental State Examination(MMSE),while psychological status was evaluated with the Hospital Anxiety and Depression Scale.PSS was identified via ultrasound,and fibrosis severity was quantified using the Coutinho index(CI).Analyses were adjusted for education level and the presence of comorbidities.Statistical analyses were performed using R software.RESULTS The prevalence of OHE was 0.5%,while MHE,diagnosed via ANT,affected 24%of patients.ANT positivity was significantly associated with the presence of PSS(35.1%vs 15.1%;P=0.0018)and higher CI scores(1.79±0.26 vs 1.30±0.84;P=0.045).Patients with MHE demonstrated notably lower MMSE scores(24.06±1.17 vs 26.04±0.63;P=0.0003),independent of education level.The ANT showed high diagnostic robustness,even among patients with limited formal education.CONCLUSION MHE is prevalent in HSS,especially with PSS,and is associated with portal hypertension severity.The ANT enables practical screening,underscoring the need for routine assessment to improve outcomes.
文摘In this paper, a new technique using a Current Shunt and a Micropotentiometer has been used to study the electrical performance of a large area multicrystalline silicon solar cell at outdoor conditions. The electrical performance is mainly described by measuring both cell short circuit current and open circuit voltage. The measurements of this cell by using multimeters suffer from some problems because the cell has high current intensity with low output voltage. So, the solar cell short circuit current values are obtained by measuring the voltage developed across a known resistance Current Shunt. Samples of the obtained current values are accurately calibrated by using a Micropotentiometer (μpot) thermal element (TE) to validate this new measuring technique. Moreover, the solar cell open circuit voltage has been measured. Besides, the cell output power has been calculated and can be correlated with the measured incident radiation.
文摘Spontaneous porto-systemic shunts(SPSS)are frequent in liver cirrhosis and their prevalence increases as liver function deteriorates,probably as a consequence of worsening portal hypertension,but without achieving an effective protection against cirrhosis'complications.Several types of SPSS have been described in the literature,each one associated with different clinical manifestations.In particular,recurrent or persistent hepatic encephalopathy is more frequent in patients with splenorenal shunt,while the presence of gastric varices and consequently the incidence of variceal bleeding is more common in gastrorenal shunt.In the advanced stage,the presence of large SPSS can lead to the so called“portosystemic shunt syndrome”,characterized by a progressive deterioration of hepatic function,hepatic encephalopathy and,sometimes,portal vein thrombosis.The detection of SPSS in patients with liver cirrhosis is recommended in order to prevent or treat recurrent hepatic encephalopathy or variceal bleeding.
基金Supported by National Natural Science Foundation of China under Grant No.81503437
文摘BACKGROUND Duodenal varices are a lesser-known complication with non-cirrhotic portal hypertension. We report a circuitous route from missed diagnosis of duodenal varices to correction. An extremely rare case of duodenal variceal bleeding secondary to idiopathic portal hypertension(IPH) is expounded in this study, which was controlled by transjugular intra-hepatic porto-systemic shunt(TIPS) plus embolization. CASE SUMMARY A 46-year-old woman with anemia for two years was frequently admitted to the local hospital. Upon examination, anemia was attributed to gastrointestinal tract bleeding, which resulted from duodenal variceal bleeding detected by repeated esophagogastroduodenoscopy. At the end of a complete workup, IPH leadingto duodenal varices was diagnosed. Portal venography revealed that the remarked duodenal varices originated from the proximal superior mesenteric vein. TIPS plus embolization with coils and Histoacryl was performed to obliterate the rupture of duodenal varices. The anemia resolved, and the duodenal varices completely vanished by 2 mo after the initial operation. CONCLUSION TIPS plus embolization may be more appropriate to treat the bleeding of large duodenal varices.
文摘Delayed liver laceration following transjugular intrahepatic portosystemic shunt (TIPS) is a serious and likely underdiagnosed complication. It is however an important complication following TIPS, which remains one of the most technically challenging interventional procedures performed. In addition to laceration, a number of complications regarding bleeding and perforation are well described following TIPS procedures. We feel the adoption of techniques such as ours and that of other authors described in the literature using an ultrasoundguided percutaneous transhepatic approach with a small caliber needle provides a safer and less traumatic procedure and should reduce complications of bleeding and almost completely eliminate the risk of liver laceration. Our procedure was successfully performed under conscious sedation rather than general anaesthesia further reducing the overall procedural risk to the patient.
文摘Gastric antral vascular ectasia(GAVE) may cause gastrointestinal bleeding(GIB). The treatment of GAVE relies on endoscopic approaches such as electrocoagulation(argon plasma coagulation, laser therapy, heater probe therapy, radiofrequency ablation), cryotherapy, and band ligation. In refractory cases, antrectomy may be considered. In the event of an associated cirrhosis and portal hypertension, it has been suggested that antrectomy could be an option, provided the mortality risk isn't considered too great. We report the case of a 67-year-old cirrhotic patient who presented with GAVE related GIB, unresponsive to multiple endoscopic treatments. The patient had a good liver function(model for end-stage disease 10). After a multidisciplinary meeting, a transjugular intrahepatic portosystemic shunt(TIPS) procedure was performed, in order to treat the cirrhosis associated ascites. The outcome was successful. An antrectomy was then performed, with no recurrence of GIB and no transfusion need during three months of follow up. In this case, the TIPS procedure achieved a complete ascites regression, allowing a safer surgical treatment of the GAVE-related GIB.
基金Project(2012AA051601)supported by the High-Tech Research and Development Program of China
文摘The open-circuit fault of the power switches in shunt active power filter(SAPF) would exacerbate the harmonic pollution of power grid, and degrade the reliability of the devices and system. A fault diagnosis method is proposed based on reference model and an over-modulation strategy under hardware fault tolerance for SAPF. First, a mathematic model is established for SAPF. Second, the residuals are generated by comparing the outputs of reference model and those of actual model, and open-switch fault is detected and diagnosed by residual evaluation. After that, hardware fault tolerance is performed with the three-phase four-switch(TPFS) topology to isolate the faulty phase. Finally, the over-modulation strategy is proposed to increase the voltage transfer ratio of the TPFS topology. Simulation and experimental results verified the feasibility and effectiveness of the proposed method.
文摘This paper proposes the evaluation of arteriovenous shunt (AVS) stenosis using a fractional-order Fuzzy Petri net based screening system for long-term hemodialysis treatment of patients. The screening system uses the Burg method, the fractional-order chaos system, and the Fuzzy Petri net (FPN) for early detection of AVS dysfunction. The Burg method is an autoregressive (AR) model that is used to estimate the frequency spectra of a phonoangiographic signal and to identify the spectral peaks in the region from 25 Hz to 800 Hz. In AVS, the frequency spectrum varies between normal blood flow and turbulent flow. The power spectra demonstrate changes in frequency and amplitude as the degree of stenosis changes. A screening system combining fractional-order chaos system and FPN is used to track the differences in the frequency spectra between the normal and stenosis access. The dynamic errors are indexes that can be used to evaluate the degree of AVS stenosis using a FPN. For 42 long-term follow-up patients, testing results show that the proposed screening system is more efficient in the evaluation of AVS stenosis.
文摘BACKGROUND There is a close relationship between cirrhosis and hepatocellular carcinoma(HCC).Transjugular intrahepatic portosystemic shunt(TIPS)has good clinical effect in treating the complication of portal hypertension.However,because of the risk of postoperative liver failure,severe complications,and low survival rate for HCC,TIPS is contraindicated in patients with portal hypertension and liver cancer.We studied a large cohort of patients with cirrhosis and HCC who underwent TIPS for recurrent variceal bleeding and/or ascites.AIM To assess the safety,efficacy,and survival rate in patients with HCC who underwent TIPS.ME THODS Group A comprised 217 patients with HCC and portal hypertension who underwent the TIPS procedure between 1999 and 2014.After TIPS deployment,these patients received palliative treatment for HCC.Group B comprised a cohort of 136 HCC patients with portal hypertension who did not undergo TIPS placement.Group B received palliative treatment for HCC plus medical therapy for portal hypertension.The clinical outcomes and survival rate were assessed.RES UL TS In Group A,the primary technical success rate was 97.69%for TIPS placement,and no severe procedure-related complications of TIPS placement were reported.The control of variceal bleeding(VB)within 1 mo did not differ significantly between the groups(P=0.261).Absorption of refractory ascites within 1 mo,recurrence of VB,and recurrence of refractory ascites differed significantly between the groups(P=0.017,0.023,and 0.009,respectively).By comparison,the rate of hepatic encephalopathy in Group B was lower than that in Group A(P=0.036).The 1-,2-,3-,4-,and 5-year survival rates were significantly different between Groups A and B(X2=12.227,P=0.018;X2=12.457,P=0.014;X2=26.490,P=0.013;X2=21.956,P=0.009,and X2=24.596,P=0.006,respectively).The mean survival time was 43.7 mo in Group A and 31.8 mo in Group B.Median survival time was 50.0 mo in Group A and 33.0 mo in Group B.Mean and median survival differed significantly between the two groups(P=0.000,X2=35.605,log-rank test).The mortality rate from VB in Group A was higher than that in Group B(P=0.006),but the rates of hepatic tumor,hepatic failure,and multiorgan failure did not differ significantly between the two groups(P=0.173,0.246 and 0.257,respectively).CONCLUSION TIPS combined with palliative treatment is safe and effective for portal hypertension in patients with HCC.
基金the Beijing Municipal Science and Technology Commission project,the Capital of the Public Health Cultivation-Transcatheter Implantation combined with TACE/TAE in the treatment of portal vein tumor thrombus in clinical research,No.Z171100000417031
文摘BACKGROUND Main portal vein tumor thrombus(MPVTT), which has a high incidence, is the major complication of terminal liver cancer. The occurrence of MPVTT is always a negative prognostic factor for patients with hepatocellular carcinoma(HCC).Therefore, attention should be paid to the treatment of MPVTT and its complications.AIM To evaluate the efficacy of transarterial chemoembolization/transarterial embolization(TACE/TAE)+^(125)I seeds implantation with transjugular intrahepatic portosystemic shunt(TIPS) in treating MPVTT and its complications.METHODS From January 2007 to March 2015, 85 consecutive patients with MPVTT were nonrandomly assigned to undergo treatment with TACE/TAE + TIPS and ^(125)I implantation(TIPS-^(125)I group) or TACE/TAE + TIPS only(TIPS only group) in Beijing Shijitan Hospital, and all clinical data were collected. During 24 mo follow-up, the incidence of overall survival, stent stenosis and symptom recurrence was analyzed to evaluate the efficacy of TIPS-^(125)I.RESULTS During 24 mo follow-up of all patients, we collected data at 6, 12 and 24 mo. The rates of survival were 80%, 45%, and 20%, respectively, in the TIPS-^(125)I group,whereas those in the TIPS only group were 64.4%, 24.4%, and 4.4%, respectively(P < 0.05). The rates of symptom recurrence were 7.5%, 22.5%, and 35%,respectively, in the TIPS-^(125)I group, whereas those in the TIPS only group were31.1%, 62.2%, and 82.2%(P < 0.05). The rates of stent restenosis were 12.5%,27.5%, and 42.5%, respectively, in the TIPS-^(125)I group, and 42.2%, 68.9%, and84.4%, respectively, in the TIPS only group(P < 0.05). TIPS-^(125)I was found to be significantly favorable in treating MPVTT and its complications in patients with HCC.CONCLUSION TACE/TAE+^(125)I combined with TIPS is effective in treating MPVTT and its complications, improving quality of life of patients and reducing mortality.
文摘Transjugular intrahepatic portosystemic shunt (TIPSS) is considered a valid therapeutic option for the treatment of portal hypertension and its complications.The guidelines for this procedure have already been established on the basis of the normal vascular anatomy and of various technical radiological aspects.In some few rare cases,diagnosis of a congenital vascular anomaly can be made accidentally by interventional radiologists,making the procedure of the TIPSS placement extremely difficult or in some cases technically impossible.This report describes a rare vascular malformation characterized by the absence of the right superior vena cava and persistence of the left superior vena cava in a patient with a diagnosis of advanced liver cirrhosis who needed a TIPSS placement in order to control refractory ascites.
基金This project was supported by the Science Fund of be Chinese Academy of Sciences
文摘The present study was aimed at dynamic observation of the ef fects of end to side portacaval shunt (PCS) and end to side mesocaval shunt (MCS) in dogs on the functions of the liver and pancreatic islet cells. According to correlation between the changes of plasma insulin level in the portal vein and hepatic flow and liver morphology after PCS and MCS, we conclude that the depletion of hepatic flow is the major factor in the deterioration of liver functions. The levels of insulin and glucagon in both the peripheral vein and the portal vein were decreased after PCS and MCS. There was also depletion of pancreatic islet A and B cells and vacuolar degeneration of the pancreas. These changes were more signifcant in PCS than in MCS, suggesting that portasystemic shunt, especially total portasystemie shunt, might damage pancreatic endocrine functions.
文摘AIM: To evaluate the clinical effects of transjugular intrahepatic portosystemic shunt (TIPS) vs endoscopic variceal sclerotherapy (EVS) in the management of gastric variceal (GV) bleeding in terms of variceal rebleeding, hepatic encephalopathy (HE), and survival by meta-analysis.METHODS: Medline, Embase, and CNKI were searched. Studies compared TIPS with EVS in treating GV bleeding were identified and included according to our predefined inclusion criteria. Data were extracted independently by two of our authors. Studies with prospective randomized design were considered to be of high quality. Hazard ratios (HRs) or odd ratios(ORs) were calculated using a fixed-effects model when there was no inter-trial heterogeneity. Oppositely, a random-effects model was employed.RESULTS: Three studies with 220 patients who had at least one episode of GV bleeding were included in the present meta-analysis. The proportions of patients with viral cirrhosis and alcoholic cirrhosis were 39% (range 0%-78%) and 36% (range 12% to 41%), respectively. The pooled incidence of variceal rebleeding in the TIPS group was significantly lower than that in the EVS group (HR = 0.3, 0.35, 95% CI: 0.17-0.71, P = 0.004). However, the risk of the development of any degree of HE was significantly increased in the TIPS group (OR = 15.97, 95% CI: 3.61-70.68). The pooled HR of survival was 1.26(95% CI: 0.76-2.09, P = 0.36). No inter-trial heterogeneity was observed among these analyses. CONCLUSION: The improved effect of TIPS in the prevention of GV rebleeding is associated with an increased risk of HE. There is no survival difference between the TIPS and EVS groups. Further studies are needed to evaluate the survival benefit of TIPS in cirrhotic patients with GV bleeding.
文摘In the present study we observed dynamically and systemically the changes of plasma somatostatin and glucagon in the peripheral and portal vein, and the changes of pancreatic immunopathology in the course of development of cirrhosis induced by CCl<sub>4</sub> and after portacaval shunt （PCS） in the cirrhotic rats as well as investigated their causes and correlationship. The results showed that hyperglucagonemia was caused by spontaneous portosystemic shunting and surgically induced portacaval anastomosis. Moreover, there was much higher level of glucagon in the portal vein with corresponding increase of A cells in PCS rats than those in the controls, indicating that another cause for elevation of glucagon was hypersecretion of pancreatic A cells. Our data demonstrated that both deterioration of liver function and portosystemic shunting might not be responsible for the elevated level of somatostatin in the cirrhotic rats with PCS. However, there was a closed positive correlation between plasma glucagon and somatostatin. Thus it was concluded that hyperglucagonemia stimulated the release of somatostatin. In view of the fact the elevated level of glucagon was much higher than that of somatostatin, there was probably a relative lack of somatostatin in cirrhosis with portal hypertension.
文摘This paper presents a fuzzy logic based three phase four wire four-leg shunt active power filter to suppress harmonic currents. Modified instantaneous p-q theory is adopted for calculating the compensating current. Fuzzy-adaptive hysteresis band technique is applied for the current control to derive the switching signals for the voltage source inverter. A fuzzy logic controller is developed to control the voltage of the DC capacitor. Computer simulations are carried out on a sample power system to demonstrate the suitability of the proposed control strategy, for harmonic reduction under three different conditions namely, ideal, unbalance, unbalance and distorted source voltage conditions. The proposed control strategy is found to be effective to reduce the harmonics and compensate reactive power and neutral current and balance load currents under ideal and non-ideal source voltage conditions.
文摘As more and more variable frequency drives (VFDs), electronic ballasts, battery chargers, and static Var compensators are installed in facilities, the problems related to harmonics are expected to get worse. As a result Active power filter (APF) gains much more attention due to excellent harmonic compensation. But still the performance of the active filter seems to be in contradictions with different control strategies. This paper presents detailed analysis to compare and elevate the performance of two control strategies for ex-tracting reference currents of shunt active filters under balanced, un-balanced and non-sinusoidal conditions by using Fuzzy controller. The well known methods, instantaneous real active and reactive power method (p-q) and active and reactive current method (id-iq) are two control methods which are extensively used in active filters. Extensive Simulations are carried out with fuzzy controller for both p-q and Id-Iq methods for different voltage conditions and adequate results were presented. Simulation results validate the superior per-formance of active and reactive current control strategy (id-iq) with fuzzy controller over active and reactive power control strategy (p-q) with fuzzy controller.
