BACKGROUND The pathophysiology behind gastroesophageal reflux disease and its association with poor outcomes after lung transplantation is incompletely understood.The physiologic impact of lung transplantation on pulm...BACKGROUND The pathophysiology behind gastroesophageal reflux disease and its association with poor outcomes after lung transplantation is incompletely understood.The physiologic impact of lung transplantation on pulmonary function,intrathoracic pressures,and vagal innervation may affect esophageal motility,bolus clearance and reflux risk.However,the effect of changes in esophageal function after lung transplantation on the risk of poor post-transplant outcomes remains unclear.AIM To evaluate the association between change in esophageal motility pre-/post-lung transplantation and rejection outcome.METHODS This was a retrospective cohort study of lung transplant recipients who underwent both pre-and post-transplant esophageal testing including high resolution manometry(HRM)at a tertiary center.Acute cellular rejection(ACR)was defined histologically per International Society for Heart and Lung Transplantation criteria.Univariate analyses were performed using student’s t-test,χ2 test,and Spearman’s correlation where appropriate.Multivariable time-to-event analysis using Cox proportional hazards model was applied.Subjects not meeting ACR outcome were censored at death or date of last clinic visit.RESULTS 55 subjects(65%men,mean age:61,median follow-up:840 days)were included,with 17 (31%) experiencing ACR. Increase in failed swallows correlated with lower baseline total lung capacity(TLC) (R = -0.32, P = 0.05) and decreased post-transplant esophageal bolus clearance (R = -0.45, P = 0.004). Onmultivariable analysis, post-transplant hypomotility independently predicted increased ACR (HR: 3.62, 95%CI:1.11-11.8;P = 0.03). Kaplan-Meier analysis demonstrated increased ACR for subjects with increased vs unchangedfailed swallows post-transplant (P = 0.048). On Cox regression, a 20% elevated risk of ACR was found for every10% increase in failed swallows, after controlling for confounders including reflux severityCONCLUSIONEsophageal hypomotility, specifically an increase in failed swallows on HRM, from pre- to post-lungtransplantation was independently associated with ACR. Additionally, lower baseline TLC correlated with increasein failed swallows, suggesting restrictive lung disease may be associated with post-transplant esophagealhypomotility. Lung transplantation may affect esophageal function and contribute to rejection outcomes. Routineesophageal function testing may help identify patients at higher risk for poor lung transplantation outcomes.展开更多
In this editorial,I present my comments on the article by Solarino et al.Conversion hip arthroplasty,which is an optional salvage procedure performed following unsuccessful fixation of intertrochanteric femur fracture...In this editorial,I present my comments on the article by Solarino et al.Conversion hip arthroplasty,which is an optional salvage procedure performed following unsuccessful fixation of intertrochanteric femur fractures in elderly pati-ents,entails more complex processes and higher rates of operative complications than primary arthroplasty.Hence,it is important to consider the appropriateness of the primary treatment choice,as well as the adequacy of nailing fixation for intertrochanteric fractures.This article briefly analyzes the possible factors contributing to the nailing failure of intertrochanteric fractures and attempts to find corresponding countermeasures to prevent fixation failures.It also analyzes the choice of treatment between nailing fixation and primary arthroplasty for intertrochanteric fractures.展开更多
An exact forecast of the failures of a sucker rod-pumped well in a production area means much for an oilfield’s operation budget, operational arrangement and production plan. In this paper, according to the characte...An exact forecast of the failures of a sucker rod-pumped well in a production area means much for an oilfield’s operation budget, operational arrangement and production plan. In this paper, according to the characteristics of failed sucker rod-pumped well randomness and strong outburst, with the gray GM (1,1) forecast model and the Markov forecast model combined, gray GM (1,1) forecast model is utilized to handle the primary data of an oilfield, and Markov forecast model is utilized to calculate the state transfer probability of forecast value. Then, the gray Markov forecast model considering the influence of randomness factors is formed. Field results prove that the calculation precision of this method is higher and the practicability is greater.展开更多
AIM: Prospective evaluation of repeat endoscopic retrograde cholangiopancreatography (ERCP) for failed Schutz grade 1 biliary cannulation in a high-volume center. METHODS: Prospective intention-to-treat analysis of pa...AIM: Prospective evaluation of repeat endoscopic retrograde cholangiopancreatography (ERCP) for failed Schutz grade 1 biliary cannulation in a high-volume center. METHODS: Prospective intention-to-treat analysis of patients referred for biliary cannulation following recent unsuccessful ERCP. RESULTS: Fifty-one patients (35 female; mean age: 62.5 years; age range: 40-87 years) with previous failed biliary cannulation were referred for repeat ERCP. The indication for ERCP was primarily choledocholithiasis (45%) or pancreatic malignancy (18%). Successful biliary can- nulation was 100%. The precut needle knife sphincterotomy (NKS) rate was 27.4%. Complications occurred in 3.9% (post-ERCP pancreatitis). An identif iable reason for initial unsuccessful biliary cannulation was present in 55% of cases. Compared to a cohort of 940 nave pa-pilla patients (female 61%; mean age: 59.9 years; age range: 18-94 years) who required sphincterotomy over the same time period, there was no statistical difference in the cannulation success rate (100% vs 98%) or postERCP pancreatitis (3.1% vs 3.9%). Precut NKS use was more frequent (27.4% vs 12.7%) (P = 0.017). CONCLUSION: Referral to a high-volume center following unsuccessful ERCP is associated with high technical success, with a favorable complication rate, compared to routine ERCP procedures.展开更多
The number of patients reinitiating dialysis after a failed transplant increases over time and has more than doubled between the year 1988 and 2010 （an increase from 2463 to 5588）. More importantly, patients returni...The number of patients reinitiating dialysis after a failed transplant increases over time and has more than doubled between the year 1988 and 2010 （an increase from 2463 to 5588）. More importantly, patients returning to dialysis have been shown to have a greater thanthree-fold increase in the annual adjusted mortality rates compared with those with a functioning graft. Continuation of immunosuppression to preserve residual graft function has been implicated to be a contributing factor, seemingly due to immunosuppression-ass-ociated cardiovascular and infectious complications and malignancy risk, among others. Nonetheless, maintenance low-dose immunosuppression has been suggested to confer survival beneft in patients returning to peritoneal dialysis. Whether early vs late reinitiation of dialysis or whether transplantectomy has an impact on patient survival remains poorly defined. Consensus guidelines for the management of a failed allograft are lacking. In this article, we present a literature overview on the ideal timing of dialysis reinitiation after graft loss, the management of immunosuppression after graft failure, and the risks and benefits of transplantectomy. The authors’ perspectives on the management of this special patient population are also discussed.展开更多
New models of safety-critical systems are built here. In these systems, when components fail, different defect states have different effects, hence need different ways to measure. In the models, there are two kinds of...New models of safety-critical systems are built here. In these systems, when components fail, different defect states have different effects, hence need different ways to measure. In the models, there are two kinds of failure modes of the components： one could be called failed-safe, and the other may be named failed- dangerous In practice, the so-called failed-dangerous components may lead a system to peril. However, failed-safe components will not. Reliability and safety issues are analyzed using Ion-Channel modeling theory to get count of repairs and time duration before the system becomes dangerous. In the closing section a numerical example is presented to illustrate the results obtained in the paper.展开更多
Patel ar instability is a common clinical problem encountered by orthopedic surgeons specializing in the knee. For patients with chronic lateral patellar instability, the standard surgical approach is to stabilize the...Patel ar instability is a common clinical problem encountered by orthopedic surgeons specializing in the knee. For patients with chronic lateral patellar instability, the standard surgical approach is to stabilize the patella through a medial patellofemoral ligament(MPFL) reconstruction. Foreseeably, an increasing number of revision surgeries of the reconstructed MPFL will be seen in upcoming years. In this paper, the causes of failed MPFL reconstruction are analyzed:(1) incorrect surgical indication or inappropriate surgical technique/patient selection;(2) a technical error; and(3) an incorrect assessment of the concomitant risk factors for instability. An understanding of the anatomy and biomechanics of the MPFL and cautiousness with the imaging techniques while favoring clinical over radiological findings and the use of common sense to determine the adequate surgical technique for each particular case, are critical to minimizing MPFL surgery failure. Additionally, our approach to dealing with failure after primary MPFL reconstruction is also presented.展开更多
A high-speed train-track coupling dynamic model is used to investigate the dynamic behavior of a high-speed train operating on a curved track with failed fasteners. The model considers a high-speed train consisting of...A high-speed train-track coupling dynamic model is used to investigate the dynamic behavior of a high-speed train operating on a curved track with failed fasteners. The model considers a high-speed train consisting of eight vehicles coupled with a ballasted track. The vehicle is modeled as a multi-body system, and the rail is modeled with a Timoshenko beam resting on the discrete sleepers. The vehicle model considers the effect of the end connections of the neighboring vehicles on the dynamic behavior. The track model takes into account the lateral, vertical, and torsional deformations of the rails and the effect of the discrete sleeper support on the coupling dynamics of the vehicles and the track. The sleepers are assumed to move backward at a constant speed to simulate the vehicle running along the track at the same speed. The train model couples with the track model by using a Hertzian contact model for the wheel/rail normal force calculation, and the nonlinear creep theory by Shen et al. (1984) is used for wheel/rail tangent force calculation. In the analysis, a curved track of 7000-m radius with failed fasteners is selected, and the effects of train operational speed and the number of failed fasteners on the dynamic behaviors of the train and the track are investigated in detail. Furthermore, the wheel/rail forces and derailment coefficient and the wheelset loading reduction are analyzed when the high-speed train passes over the curved track with the different number of continuously failed fasteners at different operational speeds. Through the detailed numerical analysis, it is found that the high-speed train can operate normally on the curved track of 7000-m radius at the speeds of 200 km/h to 350 km/h.展开更多
For high reliability and long life systems, system pass/fail data are often rare. Integrating lower-level data, such as data drawn from the subsystem or component pass/fail testing,the Bayesian analysis can improve th...For high reliability and long life systems, system pass/fail data are often rare. Integrating lower-level data, such as data drawn from the subsystem or component pass/fail testing,the Bayesian analysis can improve the precision of the system reliability assessment. If the multi-level pass/fail data are overlapping,one challenging problem for the Bayesian analysis is to develop a likelihood function. Since the computation burden of the existing methods makes them infeasible for multi-component systems, this paper proposes an improved Bayesian approach for the system reliability assessment in light of overlapping data. This approach includes three steps： fristly searching for feasible paths based on the binary decision diagram, then screening feasible points based on space partition and constraint decomposition, and finally simplifying the likelihood function. An example of a satellite rolling control system demonstrates the feasibility and the efficiency of the proposed approach.展开更多
The aim of this study was to retrospectively investigate the outcomes of patients who underwent one-stage onlay or inlay urethroplasty using a lingual mucosal graft （LMG） after failed hypospadias repairs. Inclusion ...The aim of this study was to retrospectively investigate the outcomes of patients who underwent one-stage onlay or inlay urethroplasty using a lingual mucosal graft （LMG） after failed hypospadias repairs. Inclusion criteria included a history of failed hypospadias repair, insufficiency of the local skin that made a reoperation with skin flaps difficult, and necessity of an oral mucosal graft urethroplasty. Patients were excluded if they had undergone a failed hypospadias repair using the foreskin or a multistage repair urethroplasty. Between January 2008 and December 2012, 110 patients with failed hypospadias repairs were treated in our center. Of these patients, 56 underwent a one-stage onlay or inlay urethroplasty using LMG. The median age was 21.8 years （range： 4-45 years）. Of the 56 patients, one-stage onlay LMG urethroplasty was performed in 42 patients （group 1）, and a modified Snodgrass technique using one-stage inlay LMG urethroplasty was performed in 14 （group 2）. The median LMG urethroplasty length was 5.6 ± 1.6 cm （range： 4-13 cm）. The mean follow-up was 34.7 months （range： 10-58 months）, and complications developed in 12 of 56 patients （21.4%）, including urethrocutaneous fistulas in 7 （6 in group 1, 1 in group 2） and neourethral strictures in 5 （4 in group 1, 1 in group 2）. The total success rate was 78.6%. Our survey suggests that one-stage onlay or inlay urethroplasty with LMG may be an effective option to treat the patients with less available skin after failed hypospadias repairs; LMG harvesting is easy and safe, irrespective of the patient＇s age.展开更多
AIM：To investigate the clinical outcomes of different intubation techniques in the cases of failed primary probing.METHODS： This retrospective study was performed on338 patients with the diagnosis of congenital naso...AIM：To investigate the clinical outcomes of different intubation techniques in the cases of failed primary probing.METHODS： This retrospective study was performed on338 patients with the diagnosis of congenital nasolacrimal duct obstruction with age 1-4y that had failed primary probing.Intubation was performed under light sedation in operating room and the stent was left 3mo in place.Clinical outcome was investigated 3mo after tube removal.RESULTS： Bicanalicular intubation method had higher complete and relative success rates compared to monocanalicular intubation（P =0.00）.In addition,Monoka intubation had better outcomes compared to Masterka technique（P =0.046）.No difference was found between genders but the higher the age,the better the outcomes with bicanalicular technique rather than monocanalicular.CONCLUSION： Overall success rate of bicanalicular intubation is superior to monocanalicular technique especially in older ages.Also,based upon our clinical outcomes,Masterka intubation is not recommended in cases of failed probing.展开更多
AIM: To demonstrate the outcomes of endoscopic endonasal dacryocystorhinostomy(En-DCR) with an novel lacrimal ostium stent(LOS) which was performed in patients with recurrent epiphora after failed external dacryocysto...AIM: To demonstrate the outcomes of endoscopic endonasal dacryocystorhinostomy(En-DCR) with an novel lacrimal ostium stent(LOS) which was performed in patients with recurrent epiphora after failed external dacryocystorhinostomy(Ex-DCR) and analyze the causes of failed Ex-DCR.METHODS: From September 2015 and December 2017, the clinic data of 29 cases suffered from recurrent epiphora after failed Ex-DCR was reviewed.The LOS were implanted into the ostium at the end of the revisional surgery.The causes of failed Ex-DCR were analyzed before revisional surgeries.Outcome of revisional surgeries with the new device were evaluated as well.RESULTS: The major causes of failure of the external approach were synechiae formation in the nasal ostium(29/29), followed by inadequate removal of the bony wall(21/29), nasal synechiae formation between lateral wall of nose and middle turbinate(11/29), and the bone opening was not in good location(7/29).The rate of success after revisional surgery was 82.76%.Re-obstruction of the ostiums were found in 5 failed cases.CONCLUSION: Endoscopic approach with a novel LOS may be an effective procedure to manage recurrent epiphora after previous failed Ex-DCR surgery.Synechiae formation in the nasal ostium and inadequate removal of the bony wall were the major causes of failure of Ex-DCR.展开更多
Repairing glans dehiscence after failed hypospadias repair is challenging for pediatric surgeons.Here,we introduced and evaluated a newly modified Mathieu technique,Mathieu combined tunnel(MCT),which involves multiple...Repairing glans dehiscence after failed hypospadias repair is challenging for pediatric surgeons.Here,we introduced and evaluated a newly modified Mathieu technique,Mathieu combined tunnel(MCT),which involves multiple custom-designed flaps for the shortage of flap source material after repeated operations;we also constructed a tunnel to avoid the glans incision that may carry new risks of dehiscence.This retrospective study included 26 patients who were consecutively admitted to the First Affiliated Hospital of Sun Yat-Sen University(Guangzhou,China)for glans dehiscence repair after failed hypospadias repair from October 2014 to October 2020;sixteen patients underwent surgery using the MCT(MCT group)and ten patients underwent surgery using the tubularized incised plate(TIP)technique(TIP group).The operative time,blood loss,postoperative complications,normal urethral meatus rate,success rate,and Hypospadias Objective Penile Evaluation(HOPE)score were compared between the two groups.The MCT group achieved an overall satisfactory penile appearance and voiding function,with a higher rate of normal urethral meatus(15/16,93.8%)and a lower rate of glans dehiscence(1/16,6.2%),compared with the TIP group(70.0%and 30.0%,respectively).However,these differences were not statistically significant,possibly because of the limited number of patients(all P>0.05).Mean postoperative HOPE scores were similar in the MCT group(mean±standard deviation:8.83±0.89)and TIP group(8.94±0.57)(P>0.05).No significant differences were found between the two groups in terms of blood loss and success rate,nor in the rates of various complications(e.g.,fistula,urethral stricture,and glans dehiscence).In conclusion,the MCT technique appears to be feasible and reliable for repairing glans dehiscence after failed hypospadias repair.展开更多
A retrieval control strategy for failed satellite,which is connected to a servicing spacecraft by a tether,is studied.The Lagrange analytical mechanics based dynamics modeling for the system composed of a servicing sp...A retrieval control strategy for failed satellite,which is connected to a servicing spacecraft by a tether,is studied.The Lagrange analytical mechanics based dynamics modeling for the system composed of a servicing spacecraft,a tether and a failed satellite,is presented under the earth center inertia coordinate system,then model simplification is conducted under the assumption that the failed satellite’s mass is far smaller than the servicing spacecraft’s,meanwhile the tether’s length is far smaller than the size of the servicing spacecraft’s orbit.Analysis shows that the retrieval process is intrinsically unstable as the Coriolis force functions is a negative damping.A retrieval strategy based on only the tether’s tension is designed,resulting in the fastest retrieval speed.In the proposed strategy,firstly,the tether’s swing angle amplitude is adjusted to 45?by deploying/retrieving the tether;then the tether swings freely with fixed length until it reaches negative maximum angle–45?;finally,the tether is retrieved by the pre-assigned exponential law.For simplicity,only the coplanar situation,that the tether swings in the plane of the servicing spacecraft’s orbit,is studied.Numerical simulation verifies the effectiveness of the strategy proposed.展开更多
Objective: To investigate the biological basis of qi, blood and vessel in immune thrombocytopenia(ITP) patients with syndrome of qi failing to govern blood(SQFGB) based on traditional Chinese medicine.Methods: A total...Objective: To investigate the biological basis of qi, blood and vessel in immune thrombocytopenia(ITP) patients with syndrome of qi failing to govern blood(SQFGB) based on traditional Chinese medicine.Methods: A total of 52 ITP patients with SQFCB were enrolled and divided into bleeding group(38 cases) and non-bleeding group(14 cases).Bleeding group was further divided into mild qi deficiency group(25 cases) and moderate/severe qi deficiency group(13 cases) based on Chinese Medicine syndrome score.20 healthy volunteer were recruited as control group.The count of platelet(PLT) was taken as the blood related indicator.The expressions of cytokines including IL-1β, IL-17 A, TNF-α, CD40 L, and TGF-β, detected by Aim Plex Multiple Immunoassays for Flow, were taken as the qi related indicators.The expressions of VEGF-A, detected by Aim Plex Multiple Immunoassays for Flow and NO, NOS, and ET-1 detected by ELISA, were taken as the vessel related indicators.Results: As compared to the control group, the count of PLT, taken as the blood related indicator, was significantly lower in ITP group patients with SQFCB(P<0.05).The expression levels of IL-17 A and TNF-α, taken as the qi related indicators, were significantly higher, while those of CD40 L, IL-1β, and TGF-β, also taken as the qi related indicators, were significantly lower in ITP patients with SQFCB, respectively(P<0.05).The expression levels of NO and ET-1, taken as the vessel related indicators, were significantly higher, while the expression levels of NOS and VEGF-A also taken as the vessel related indicators, were significantly lower in ITP patients with SQFCB, respectively(P<0.05).The count of PLT, taken as the blood related indicator, was significantly lower in moderate/severe group than those in mild group(P<0.05).The expression levels of CD40 L and TGF-β, taken as the qi related indicators, were also significantly lower in moderate/severe group than those in mild group, respectively(P<0.05).Conclusion: The count of PLT might be the biological basis of blood.The expressions of NO, NOS, ET-1 and VEGF-A might be the biological basis of vessel.The expressions of IL-1β, IL-17 A, TNF-α, TGF-β, and CD40 L may be the biological basis of qi.The expressions of CD40 L and TGF-β could reflect the degree of qi deficiency in ITP patients based on the theory of qi and blood.展开更多
文摘BACKGROUND The pathophysiology behind gastroesophageal reflux disease and its association with poor outcomes after lung transplantation is incompletely understood.The physiologic impact of lung transplantation on pulmonary function,intrathoracic pressures,and vagal innervation may affect esophageal motility,bolus clearance and reflux risk.However,the effect of changes in esophageal function after lung transplantation on the risk of poor post-transplant outcomes remains unclear.AIM To evaluate the association between change in esophageal motility pre-/post-lung transplantation and rejection outcome.METHODS This was a retrospective cohort study of lung transplant recipients who underwent both pre-and post-transplant esophageal testing including high resolution manometry(HRM)at a tertiary center.Acute cellular rejection(ACR)was defined histologically per International Society for Heart and Lung Transplantation criteria.Univariate analyses were performed using student’s t-test,χ2 test,and Spearman’s correlation where appropriate.Multivariable time-to-event analysis using Cox proportional hazards model was applied.Subjects not meeting ACR outcome were censored at death or date of last clinic visit.RESULTS 55 subjects(65%men,mean age:61,median follow-up:840 days)were included,with 17 (31%) experiencing ACR. Increase in failed swallows correlated with lower baseline total lung capacity(TLC) (R = -0.32, P = 0.05) and decreased post-transplant esophageal bolus clearance (R = -0.45, P = 0.004). Onmultivariable analysis, post-transplant hypomotility independently predicted increased ACR (HR: 3.62, 95%CI:1.11-11.8;P = 0.03). Kaplan-Meier analysis demonstrated increased ACR for subjects with increased vs unchangedfailed swallows post-transplant (P = 0.048). On Cox regression, a 20% elevated risk of ACR was found for every10% increase in failed swallows, after controlling for confounders including reflux severityCONCLUSIONEsophageal hypomotility, specifically an increase in failed swallows on HRM, from pre- to post-lungtransplantation was independently associated with ACR. Additionally, lower baseline TLC correlated with increasein failed swallows, suggesting restrictive lung disease may be associated with post-transplant esophagealhypomotility. Lung transplantation may affect esophageal function and contribute to rejection outcomes. Routineesophageal function testing may help identify patients at higher risk for poor lung transplantation outcomes.
文摘In this editorial,I present my comments on the article by Solarino et al.Conversion hip arthroplasty,which is an optional salvage procedure performed following unsuccessful fixation of intertrochanteric femur fractures in elderly pati-ents,entails more complex processes and higher rates of operative complications than primary arthroplasty.Hence,it is important to consider the appropriateness of the primary treatment choice,as well as the adequacy of nailing fixation for intertrochanteric fractures.This article briefly analyzes the possible factors contributing to the nailing failure of intertrochanteric fractures and attempts to find corresponding countermeasures to prevent fixation failures.It also analyzes the choice of treatment between nailing fixation and primary arthroplasty for intertrochanteric fractures.
文摘An exact forecast of the failures of a sucker rod-pumped well in a production area means much for an oilfield’s operation budget, operational arrangement and production plan. In this paper, according to the characteristics of failed sucker rod-pumped well randomness and strong outburst, with the gray GM (1,1) forecast model and the Markov forecast model combined, gray GM (1,1) forecast model is utilized to handle the primary data of an oilfield, and Markov forecast model is utilized to calculate the state transfer probability of forecast value. Then, the gray Markov forecast model considering the influence of randomness factors is formed. Field results prove that the calculation precision of this method is higher and the practicability is greater.
文摘AIM: Prospective evaluation of repeat endoscopic retrograde cholangiopancreatography (ERCP) for failed Schutz grade 1 biliary cannulation in a high-volume center. METHODS: Prospective intention-to-treat analysis of patients referred for biliary cannulation following recent unsuccessful ERCP. RESULTS: Fifty-one patients (35 female; mean age: 62.5 years; age range: 40-87 years) with previous failed biliary cannulation were referred for repeat ERCP. The indication for ERCP was primarily choledocholithiasis (45%) or pancreatic malignancy (18%). Successful biliary can- nulation was 100%. The precut needle knife sphincterotomy (NKS) rate was 27.4%. Complications occurred in 3.9% (post-ERCP pancreatitis). An identif iable reason for initial unsuccessful biliary cannulation was present in 55% of cases. Compared to a cohort of 940 nave pa-pilla patients (female 61%; mean age: 59.9 years; age range: 18-94 years) who required sphincterotomy over the same time period, there was no statistical difference in the cannulation success rate (100% vs 98%) or postERCP pancreatitis (3.1% vs 3.9%). Precut NKS use was more frequent (27.4% vs 12.7%) (P = 0.017). CONCLUSION: Referral to a high-volume center following unsuccessful ERCP is associated with high technical success, with a favorable complication rate, compared to routine ERCP procedures.
文摘The number of patients reinitiating dialysis after a failed transplant increases over time and has more than doubled between the year 1988 and 2010 （an increase from 2463 to 5588）. More importantly, patients returning to dialysis have been shown to have a greater thanthree-fold increase in the annual adjusted mortality rates compared with those with a functioning graft. Continuation of immunosuppression to preserve residual graft function has been implicated to be a contributing factor, seemingly due to immunosuppression-ass-ociated cardiovascular and infectious complications and malignancy risk, among others. Nonetheless, maintenance low-dose immunosuppression has been suggested to confer survival beneft in patients returning to peritoneal dialysis. Whether early vs late reinitiation of dialysis or whether transplantectomy has an impact on patient survival remains poorly defined. Consensus guidelines for the management of a failed allograft are lacking. In this article, we present a literature overview on the ideal timing of dialysis reinitiation after graft loss, the management of immunosuppression after graft failure, and the risks and benefits of transplantectomy. The authors’ perspectives on the management of this special patient population are also discussed.
基金Sponsored by 211 Project of Minzu University of China(021211030312)
文摘New models of safety-critical systems are built here. In these systems, when components fail, different defect states have different effects, hence need different ways to measure. In the models, there are two kinds of failure modes of the components： one could be called failed-safe, and the other may be named failed- dangerous In practice, the so-called failed-dangerous components may lead a system to peril. However, failed-safe components will not. Reliability and safety issues are analyzed using Ion-Channel modeling theory to get count of repairs and time duration before the system becomes dangerous. In the closing section a numerical example is presented to illustrate the results obtained in the paper.
文摘Patel ar instability is a common clinical problem encountered by orthopedic surgeons specializing in the knee. For patients with chronic lateral patellar instability, the standard surgical approach is to stabilize the patella through a medial patellofemoral ligament(MPFL) reconstruction. Foreseeably, an increasing number of revision surgeries of the reconstructed MPFL will be seen in upcoming years. In this paper, the causes of failed MPFL reconstruction are analyzed:(1) incorrect surgical indication or inappropriate surgical technique/patient selection;(2) a technical error; and(3) an incorrect assessment of the concomitant risk factors for instability. An understanding of the anatomy and biomechanics of the MPFL and cautiousness with the imaging techniques while favoring clinical over radiological findings and the use of common sense to determine the adequate surgical technique for each particular case, are critical to minimizing MPFL surgery failure. Additionally, our approach to dealing with failure after primary MPFL reconstruction is also presented.
基金Project supported by the National Natural Science Foundation of China (No. U1134202)the National Basic Research Program (973) of China (No. 2011CB711103)the Program for Changjiang Scholars and Innovative Research Team in University (Nos. IRT1178and SWJTU12ZT01), China
文摘A high-speed train-track coupling dynamic model is used to investigate the dynamic behavior of a high-speed train operating on a curved track with failed fasteners. The model considers a high-speed train consisting of eight vehicles coupled with a ballasted track. The vehicle is modeled as a multi-body system, and the rail is modeled with a Timoshenko beam resting on the discrete sleepers. The vehicle model considers the effect of the end connections of the neighboring vehicles on the dynamic behavior. The track model takes into account the lateral, vertical, and torsional deformations of the rails and the effect of the discrete sleeper support on the coupling dynamics of the vehicles and the track. The sleepers are assumed to move backward at a constant speed to simulate the vehicle running along the track at the same speed. The train model couples with the track model by using a Hertzian contact model for the wheel/rail normal force calculation, and the nonlinear creep theory by Shen et al. (1984) is used for wheel/rail tangent force calculation. In the analysis, a curved track of 7000-m radius with failed fasteners is selected, and the effects of train operational speed and the number of failed fasteners on the dynamic behaviors of the train and the track are investigated in detail. Furthermore, the wheel/rail forces and derailment coefficient and the wheelset loading reduction are analyzed when the high-speed train passes over the curved track with the different number of continuously failed fasteners at different operational speeds. Through the detailed numerical analysis, it is found that the high-speed train can operate normally on the curved track of 7000-m radius at the speeds of 200 km/h to 350 km/h.
基金supported by the National Natural Science Foundation of China(61304218)
文摘For high reliability and long life systems, system pass/fail data are often rare. Integrating lower-level data, such as data drawn from the subsystem or component pass/fail testing,the Bayesian analysis can improve the precision of the system reliability assessment. If the multi-level pass/fail data are overlapping,one challenging problem for the Bayesian analysis is to develop a likelihood function. Since the computation burden of the existing methods makes them infeasible for multi-component systems, this paper proposes an improved Bayesian approach for the system reliability assessment in light of overlapping data. This approach includes three steps： fristly searching for feasible paths based on the binary decision diagram, then screening feasible points based on space partition and constraint decomposition, and finally simplifying the likelihood function. An example of a satellite rolling control system demonstrates the feasibility and the efficiency of the proposed approach.
文摘The aim of this study was to retrospectively investigate the outcomes of patients who underwent one-stage onlay or inlay urethroplasty using a lingual mucosal graft （LMG） after failed hypospadias repairs. Inclusion criteria included a history of failed hypospadias repair, insufficiency of the local skin that made a reoperation with skin flaps difficult, and necessity of an oral mucosal graft urethroplasty. Patients were excluded if they had undergone a failed hypospadias repair using the foreskin or a multistage repair urethroplasty. Between January 2008 and December 2012, 110 patients with failed hypospadias repairs were treated in our center. Of these patients, 56 underwent a one-stage onlay or inlay urethroplasty using LMG. The median age was 21.8 years （range： 4-45 years）. Of the 56 patients, one-stage onlay LMG urethroplasty was performed in 42 patients （group 1）, and a modified Snodgrass technique using one-stage inlay LMG urethroplasty was performed in 14 （group 2）. The median LMG urethroplasty length was 5.6 ± 1.6 cm （range： 4-13 cm）. The mean follow-up was 34.7 months （range： 10-58 months）, and complications developed in 12 of 56 patients （21.4%）, including urethrocutaneous fistulas in 7 （6 in group 1, 1 in group 2） and neourethral strictures in 5 （4 in group 1, 1 in group 2）. The total success rate was 78.6%. Our survey suggests that one-stage onlay or inlay urethroplasty with LMG may be an effective option to treat the patients with less available skin after failed hypospadias repairs; LMG harvesting is easy and safe, irrespective of the patient＇s age.
文摘AIM：To investigate the clinical outcomes of different intubation techniques in the cases of failed primary probing.METHODS： This retrospective study was performed on338 patients with the diagnosis of congenital nasolacrimal duct obstruction with age 1-4y that had failed primary probing.Intubation was performed under light sedation in operating room and the stent was left 3mo in place.Clinical outcome was investigated 3mo after tube removal.RESULTS： Bicanalicular intubation method had higher complete and relative success rates compared to monocanalicular intubation（P =0.00）.In addition,Monoka intubation had better outcomes compared to Masterka technique（P =0.046）.No difference was found between genders but the higher the age,the better the outcomes with bicanalicular technique rather than monocanalicular.CONCLUSION： Overall success rate of bicanalicular intubation is superior to monocanalicular technique especially in older ages.Also,based upon our clinical outcomes,Masterka intubation is not recommended in cases of failed probing.
基金Supported by Wenzhou Science and Technology Bureau Program (No.Y2020362)。
文摘AIM: To demonstrate the outcomes of endoscopic endonasal dacryocystorhinostomy(En-DCR) with an novel lacrimal ostium stent(LOS) which was performed in patients with recurrent epiphora after failed external dacryocystorhinostomy(Ex-DCR) and analyze the causes of failed Ex-DCR.METHODS: From September 2015 and December 2017, the clinic data of 29 cases suffered from recurrent epiphora after failed Ex-DCR was reviewed.The LOS were implanted into the ostium at the end of the revisional surgery.The causes of failed Ex-DCR were analyzed before revisional surgeries.Outcome of revisional surgeries with the new device were evaluated as well.RESULTS: The major causes of failure of the external approach were synechiae formation in the nasal ostium(29/29), followed by inadequate removal of the bony wall(21/29), nasal synechiae formation between lateral wall of nose and middle turbinate(11/29), and the bone opening was not in good location(7/29).The rate of success after revisional surgery was 82.76%.Re-obstruction of the ostiums were found in 5 failed cases.CONCLUSION: Endoscopic approach with a novel LOS may be an effective procedure to manage recurrent epiphora after previous failed Ex-DCR surgery.Synechiae formation in the nasal ostium and inadequate removal of the bony wall were the major causes of failure of Ex-DCR.
基金supported by grants from the National Natural Science Foundation of China(No.81971314)。
文摘Repairing glans dehiscence after failed hypospadias repair is challenging for pediatric surgeons.Here,we introduced and evaluated a newly modified Mathieu technique,Mathieu combined tunnel(MCT),which involves multiple custom-designed flaps for the shortage of flap source material after repeated operations;we also constructed a tunnel to avoid the glans incision that may carry new risks of dehiscence.This retrospective study included 26 patients who were consecutively admitted to the First Affiliated Hospital of Sun Yat-Sen University(Guangzhou,China)for glans dehiscence repair after failed hypospadias repair from October 2014 to October 2020;sixteen patients underwent surgery using the MCT(MCT group)and ten patients underwent surgery using the tubularized incised plate(TIP)technique(TIP group).The operative time,blood loss,postoperative complications,normal urethral meatus rate,success rate,and Hypospadias Objective Penile Evaluation(HOPE)score were compared between the two groups.The MCT group achieved an overall satisfactory penile appearance and voiding function,with a higher rate of normal urethral meatus(15/16,93.8%)and a lower rate of glans dehiscence(1/16,6.2%),compared with the TIP group(70.0%and 30.0%,respectively).However,these differences were not statistically significant,possibly because of the limited number of patients(all P>0.05).Mean postoperative HOPE scores were similar in the MCT group(mean±standard deviation:8.83±0.89)and TIP group(8.94±0.57)(P>0.05).No significant differences were found between the two groups in terms of blood loss and success rate,nor in the rates of various complications(e.g.,fistula,urethral stricture,and glans dehiscence).In conclusion,the MCT technique appears to be feasible and reliable for repairing glans dehiscence after failed hypospadias repair.
基金supported by the Fundamental Research Funds for the Central Universities(NUAA-NS2016082)
文摘A retrieval control strategy for failed satellite,which is connected to a servicing spacecraft by a tether,is studied.The Lagrange analytical mechanics based dynamics modeling for the system composed of a servicing spacecraft,a tether and a failed satellite,is presented under the earth center inertia coordinate system,then model simplification is conducted under the assumption that the failed satellite’s mass is far smaller than the servicing spacecraft’s,meanwhile the tether’s length is far smaller than the size of the servicing spacecraft’s orbit.Analysis shows that the retrieval process is intrinsically unstable as the Coriolis force functions is a negative damping.A retrieval strategy based on only the tether’s tension is designed,resulting in the fastest retrieval speed.In the proposed strategy,firstly,the tether’s swing angle amplitude is adjusted to 45?by deploying/retrieving the tether;then the tether swings freely with fixed length until it reaches negative maximum angle–45?;finally,the tether is retrieved by the pre-assigned exponential law.For simplicity,only the coplanar situation,that the tether swings in the plane of the servicing spacecraft’s orbit,is studied.Numerical simulation verifies the effectiveness of the strategy proposed.
基金the National Program on Key Basic Research Project(2015CB554403)
文摘Objective: To investigate the biological basis of qi, blood and vessel in immune thrombocytopenia(ITP) patients with syndrome of qi failing to govern blood(SQFGB) based on traditional Chinese medicine.Methods: A total of 52 ITP patients with SQFCB were enrolled and divided into bleeding group(38 cases) and non-bleeding group(14 cases).Bleeding group was further divided into mild qi deficiency group(25 cases) and moderate/severe qi deficiency group(13 cases) based on Chinese Medicine syndrome score.20 healthy volunteer were recruited as control group.The count of platelet(PLT) was taken as the blood related indicator.The expressions of cytokines including IL-1β, IL-17 A, TNF-α, CD40 L, and TGF-β, detected by Aim Plex Multiple Immunoassays for Flow, were taken as the qi related indicators.The expressions of VEGF-A, detected by Aim Plex Multiple Immunoassays for Flow and NO, NOS, and ET-1 detected by ELISA, were taken as the vessel related indicators.Results: As compared to the control group, the count of PLT, taken as the blood related indicator, was significantly lower in ITP group patients with SQFCB(P<0.05).The expression levels of IL-17 A and TNF-α, taken as the qi related indicators, were significantly higher, while those of CD40 L, IL-1β, and TGF-β, also taken as the qi related indicators, were significantly lower in ITP patients with SQFCB, respectively(P<0.05).The expression levels of NO and ET-1, taken as the vessel related indicators, were significantly higher, while the expression levels of NOS and VEGF-A also taken as the vessel related indicators, were significantly lower in ITP patients with SQFCB, respectively(P<0.05).The count of PLT, taken as the blood related indicator, was significantly lower in moderate/severe group than those in mild group(P<0.05).The expression levels of CD40 L and TGF-β, taken as the qi related indicators, were also significantly lower in moderate/severe group than those in mild group, respectively(P<0.05).Conclusion: The count of PLT might be the biological basis of blood.The expressions of NO, NOS, ET-1 and VEGF-A might be the biological basis of vessel.The expressions of IL-1β, IL-17 A, TNF-α, TGF-β, and CD40 L may be the biological basis of qi.The expressions of CD40 L and TGF-β could reflect the degree of qi deficiency in ITP patients based on the theory of qi and blood.
