Quantifying the post-earthquake functional recovery of railway stations presents significant challenges.This paper first establishes a post-earthquake function calculation method for railway stations,encompassing the ...Quantifying the post-earthquake functional recovery of railway stations presents significant challenges.This paper first establishes a post-earthquake function calculation method for railway stations,encompassing the establishment of relationships between the station’s function and the damage state,function loss,and failure probability of components and professional equipment in each layer.Also,the“4 stages-6 sequences”post-earthquake repair method is present,taking into account the functional and structural characteristics of railway stations.Additionally,a novel piecewise function for the post-earthquake functional dynamic recovery of railway stations is developed.A case study is conducted on a typical railway station to demonstrate the analysis procedure.Results indicate that under fortification,rare,and extremely rare earthquake scenarios,the interlayer drift ratio(IDR)of the railway station were 1/276,1/143,and 1/52,respectively,and corresponding peak floor acceleration(PFA)were 6.31 m/s^(2),7.82 m/s^(2),and 8.57 m/s^(2),respectively.The post-earthquake function of the railway station was 93.21%,82.33%,and 64.16%of its initial function.The repair times were 6.66 days,18.65 days,and 37.42 days.The displacement-sensitive,non-structural components were identified as the most vulnerable to damage.And the first repair stage(R_(1))which was mainly used to repair structural components and non-structural transport components,accounted for the highest proportion of total repair time.展开更多
Experience from past earthquakes has demonstrated the need to account for design goals beyond safety,known as functional recovery objectives,in the interest of community resilience.Frameworks have been proposed in the...Experience from past earthquakes has demonstrated the need to account for design goals beyond safety,known as functional recovery objectives,in the interest of community resilience.Frameworks have been proposed in the literature to assess the post-earthquake functional recovery of a building,but without accounting for utility systems’disruption,which may be a key contributor to determining when a building is functional.This paper integrates a previously proposed probabilistic method for estimating the post-earthquake restoration of critical utility services with an individual building’s functional recovery assessment framework.The integration was performed by incorporating utilities into the building system fault trees embedded into a functional recovery framework for various building occupancies(residential and commercial office buildings).Once incorporated,the results are used to interrogate the functional recovery of a reinforced concrete building,and the recovery time results were presented for seven cases investigating contributing factors in the functional recovery results including the number of crews available for lifeline restoration,the effect of low-quality service on meeting tenant requirements for elevators,heating ventilation and air conditioning(HVAC),plumbing and electrical systems,consideration of fire watch,the effect of building seismic retrofit,as well as different cases of fragility functions for the lifeline systems.Results showed that utility systems’disruption does not have a significant impact on the recoccupancy of a building because only one utility-dependent building system(fire suppression)is needed for the building’s safety.Unlike reoccupancy,utility systems are significant for functional recovery,mainly at moderate hazard levels because,at these levels,lifeline networks could be damaged without significant building damage,such that the lifeline systems restoration governs.Buildings with more restrictive tenant requirements are more sensitive to tenant disruptions.展开更多
Epidural electrical stimulation can restore limb motor function after spinal cord injury by reactivating the surviving neural circuits.In previous epidural electrical stimulation studies,single electrode sites and con...Epidural electrical stimulation can restore limb motor function after spinal cord injury by reactivating the surviving neural circuits.In previous epidural electrical stimulation studies,single electrode sites and continuous tetanic stimulation have often been used.With this stimulation,the body is prone to declines in tolerance and locomotion coordination.In the present study,rat models of complete spinal cord injury were established by vertically cutting the spinal cord at the T8 level to eliminate disturbance from residual nerve fibers,and were then subjected to epidural electrical stimulation.The flexible extradural electrode had good anatomical topology and matched the shape of the spinal canal of the implanted segment.Simultaneously,the electrode stimulation site was able to be accurately applied to the L2–3 and S1 segments of the spinal cord.To evaluate the biocompatibility of the implanted epidural electrical stimulation electrodes,GFAP/Iba-1 doublelabeled immunofluorescence staining was performed on the spinal cord below the electrodes at 7 days after the electrode implantation.Immunofluorescence results revealed no significant differences in the numbers or morphologies of microglia and astrocytes in the spinal cord after electrode implantation,and there was no activated Iba-1~+cell aggregation,indicating that the implant did not cause an inflammatory response in the spinal cord.Rat gait analysis showed that,at 3 days after surgery,gait became coordinated in rats with spinal cord injury under burst stimulation.The regained locomotion could clearly distinguish the support phase and the swing phase and dynamically adjust with the frequency of stimulus distribution.To evaluate the matching degree between the flexible epidural electrode(including three stimulation contacts),vertebral morphology,and the level of the epidural site of the stimulation electrode,micro-CT was used to scan the thoracolumbar vertebrae of rats before and after electrode implantation.Based on the experimental results of gait recovery using three-site stimulation electrodes at L2–3 and S1 combined with burst stimulation in a rat model of spinal cord injury,epidural electrical stimulation is a promising protocol that needs to be further explored.This study was approved by the Animal Ethics Committee of Chinese PLA General Hospital(approval No.2019-X15-39)on April 19,2019.展开更多
Objective:To judge the efficacies of neural stem cell(NSC)transplantation on functional recovery following contusion spinal cord injuries(SCIs).Data sources:Studies in which NSCs were transplanted into a clinically re...Objective:To judge the efficacies of neural stem cell(NSC)transplantation on functional recovery following contusion spinal cord injuries(SCIs).Data sources:Studies in which NSCs were transplanted into a clinically relevant,standardized rat model of contusion SCI were identified by searching the PubMed,Embase and Cochrane databases,and the extracted data were analyzed by Stata 14.0.Data selection:Inclusion criteria were that NSCs were used in in vivo animal studies to treat contusion SCIs and that behavioral assessment of locomotor functional recovery was performed using the Basso,Beattie,and Bresnahan lo-comotor rating scale.Exclusion criteria included a follow-up of less than 4 weeks and the lack of control groups.Outcome measures:The restoration of motor function was assessed by the Basso,Beattie,and Bresnahan locomotor rating scale.Results:We identified 1756 non-duplicated papers by searching the aforementioned electronic databases,and 30 full-text articles met the inclusion criteria.A total of 37 studies reported in the 30 articles were included in the meta-analysis.The meta-analysis results showed that transplanted NSCs could improve the motor function recovery of rats following contusion SCIs,to a moderate extent(pooled standardized mean difference(SMD)=0.73;95%confidence interval(CI):0.47–1.00;P<0.001).NSCs obtained from different donor species(rat:SMD=0.74;95%CI:0.36–1.13;human:SMD=0.78;95%CI:0.31–1.25),at different donor ages(fetal:SMD=0.67;95%CI:0.43–0.92;adult:SMD=0.86;95%CI:0.50–1.22)and from different origins(brain-derived:SMD=0.59;95%CI:0.27–0.91;spinal cord-derived:SMD=0.51;95%CI:0.22–0.79)had similar efficacies on improved functional recovery;however,adult induced pluripotent stem cell-derived NSCs showed no significant efficacies.Furthermore,the use of higher doses of transplanted NSCs or the administration of immunosuppressive agents did not promote better locomotor function recovery(SMD=0.45;95%CI:0.21–0.70).However,shorter periods between the contusion induction and the NSC transplantation showed slightly higher efficacies(acute:SMD=1.22;95%CI:0.81–1.63;subacute:SMD=0.75;95%CI:0.42–1.09).For chronic injuries,NSC implantation did not significantly improve functional recovery(SMD=0.25;95%CI:–0.16 to 0.65).Conclusion:NSC transplantation alone appears to be a positive yet limited method for the treatment of contusion SCIs.展开更多
Functional electrical stimulation is an effective way to rebuild hindlimb motor function after spinal cord injury.However,no site map exists to serve as a reference for implanting stimulator electrodes.In this study,r...Functional electrical stimulation is an effective way to rebuild hindlimb motor function after spinal cord injury.However,no site map exists to serve as a reference for implanting stimulator electrodes.In this study,rat models of thoracic spinal nerve 9 contusion were established by a heavy-impact method and rat models of T6/8/9 spinal cord injury were established by a transection method.Intraspinal microstimulation was performed to record motion types,site coordinates,and threshold currents induced by stimulation.After transection(complete injury),the core region of hip flexion migrated from the T13 to T12 vertebral segment,and the core region of hip extension migrated from the L1 to T13 vertebral segment.Migration was affected by post-transection time,but not transection segment.Moreover,the longer the post-transection time,the longer the distance of migration.This study provides a reference for spinal electrode implantation after spinal cord injury.This study was approved by the Institutional Animal Care and Use Committee of Nantong University,China(approval No.20190225-008)on February 26,2019.展开更多
This paper presents an adaptive rationalized Haar function approximation method to obtain the optimal injection strategy for alkali-surfactant-polymer(ASP) flooding. In this process, the non-uniform control vector par...This paper presents an adaptive rationalized Haar function approximation method to obtain the optimal injection strategy for alkali-surfactant-polymer(ASP) flooding. In this process, the non-uniform control vector parameterization is introduced to convert original problem into a multistage optimization problem, in which a new normalized time variable is adopted on the combination of the subinterval length. Then the rationalized Haar function approximation method, in which an auxiliary function is introduced to dispose path constraints, is used to transform the multistage problem into a nonlinear programming. Furthermore, an adaptive strategy proposed on the basis of errors is adopted to regulate the order of Haar function vectors. Finally, the nonlinear programming for ASP flooding is solved by sequential quadratic programming. To illustrate the performance of proposed method,the experimental comparison method and control vector parameterization(CVP) method are introduced to optimize the original problem directly. By contrastive analysis of results, the accuracy and efficiency of proposed method are confirmed.展开更多
基金National Natural Science Foundation of China under Grant No.52278534the Sichuan Provincial Natural Science Foundation of China under Grant No.2022NSFSC0423。
文摘Quantifying the post-earthquake functional recovery of railway stations presents significant challenges.This paper first establishes a post-earthquake function calculation method for railway stations,encompassing the establishment of relationships between the station’s function and the damage state,function loss,and failure probability of components and professional equipment in each layer.Also,the“4 stages-6 sequences”post-earthquake repair method is present,taking into account the functional and structural characteristics of railway stations.Additionally,a novel piecewise function for the post-earthquake functional dynamic recovery of railway stations is developed.A case study is conducted on a typical railway station to demonstrate the analysis procedure.Results indicate that under fortification,rare,and extremely rare earthquake scenarios,the interlayer drift ratio(IDR)of the railway station were 1/276,1/143,and 1/52,respectively,and corresponding peak floor acceleration(PFA)were 6.31 m/s^(2),7.82 m/s^(2),and 8.57 m/s^(2),respectively.The post-earthquake function of the railway station was 93.21%,82.33%,and 64.16%of its initial function.The repair times were 6.66 days,18.65 days,and 37.42 days.The displacement-sensitive,non-structural components were identified as the most vulnerable to damage.And the first repair stage(R_(1))which was mainly used to repair structural components and non-structural transport components,accounted for the highest proportion of total repair time.
基金Financial support for this work was provided by the US Depart-ment of Commerce,National Institute of Standards and Technology un-der the Financial Assistance Award Number#70NANB19H058.
文摘Experience from past earthquakes has demonstrated the need to account for design goals beyond safety,known as functional recovery objectives,in the interest of community resilience.Frameworks have been proposed in the literature to assess the post-earthquake functional recovery of a building,but without accounting for utility systems’disruption,which may be a key contributor to determining when a building is functional.This paper integrates a previously proposed probabilistic method for estimating the post-earthquake restoration of critical utility services with an individual building’s functional recovery assessment framework.The integration was performed by incorporating utilities into the building system fault trees embedded into a functional recovery framework for various building occupancies(residential and commercial office buildings).Once incorporated,the results are used to interrogate the functional recovery of a reinforced concrete building,and the recovery time results were presented for seven cases investigating contributing factors in the functional recovery results including the number of crews available for lifeline restoration,the effect of low-quality service on meeting tenant requirements for elevators,heating ventilation and air conditioning(HVAC),plumbing and electrical systems,consideration of fire watch,the effect of building seismic retrofit,as well as different cases of fragility functions for the lifeline systems.Results showed that utility systems’disruption does not have a significant impact on the recoccupancy of a building because only one utility-dependent building system(fire suppression)is needed for the building’s safety.Unlike reoccupancy,utility systems are significant for functional recovery,mainly at moderate hazard levels because,at these levels,lifeline networks could be damaged without significant building damage,such that the lifeline systems restoration governs.Buildings with more restrictive tenant requirements are more sensitive to tenant disruptions.
基金supported by the National Natural Science Foundation of China,Nos.81601052(to XRJ),81520108017(to PFT)the Beijing Nova Program of Science and Technology of China,No.2018034(to XRJ)+1 种基金the Beijing Municipal Science and Technology Project of China,No.D16100002816005(to PFT)the Subsidiary of PLA Major Project of China,No.AWS17J004(to PFT)。
文摘Epidural electrical stimulation can restore limb motor function after spinal cord injury by reactivating the surviving neural circuits.In previous epidural electrical stimulation studies,single electrode sites and continuous tetanic stimulation have often been used.With this stimulation,the body is prone to declines in tolerance and locomotion coordination.In the present study,rat models of complete spinal cord injury were established by vertically cutting the spinal cord at the T8 level to eliminate disturbance from residual nerve fibers,and were then subjected to epidural electrical stimulation.The flexible extradural electrode had good anatomical topology and matched the shape of the spinal canal of the implanted segment.Simultaneously,the electrode stimulation site was able to be accurately applied to the L2–3 and S1 segments of the spinal cord.To evaluate the biocompatibility of the implanted epidural electrical stimulation electrodes,GFAP/Iba-1 doublelabeled immunofluorescence staining was performed on the spinal cord below the electrodes at 7 days after the electrode implantation.Immunofluorescence results revealed no significant differences in the numbers or morphologies of microglia and astrocytes in the spinal cord after electrode implantation,and there was no activated Iba-1~+cell aggregation,indicating that the implant did not cause an inflammatory response in the spinal cord.Rat gait analysis showed that,at 3 days after surgery,gait became coordinated in rats with spinal cord injury under burst stimulation.The regained locomotion could clearly distinguish the support phase and the swing phase and dynamically adjust with the frequency of stimulus distribution.To evaluate the matching degree between the flexible epidural electrode(including three stimulation contacts),vertebral morphology,and the level of the epidural site of the stimulation electrode,micro-CT was used to scan the thoracolumbar vertebrae of rats before and after electrode implantation.Based on the experimental results of gait recovery using three-site stimulation electrodes at L2–3 and S1 combined with burst stimulation in a rat model of spinal cord injury,epidural electrical stimulation is a promising protocol that needs to be further explored.This study was approved by the Animal Ethics Committee of Chinese PLA General Hospital(approval No.2019-X15-39)on April 19,2019.
基金supported by the National Natural Science Foundation of China,No.81171147“Key Medical Talents of Qiangwei Project” Research Foundation of Health Department of Jiangsu Province of China,No.ZDRCA2016010+1 种基金“Xingwei Project” Key Personal Medical Research Foundation of Health Department of Jiangsu Province of China,No.RC201156Jiangsu Provincial Key Discipline of Medicine of China,No.XK201117(all to LXL)
文摘Objective:To judge the efficacies of neural stem cell(NSC)transplantation on functional recovery following contusion spinal cord injuries(SCIs).Data sources:Studies in which NSCs were transplanted into a clinically relevant,standardized rat model of contusion SCI were identified by searching the PubMed,Embase and Cochrane databases,and the extracted data were analyzed by Stata 14.0.Data selection:Inclusion criteria were that NSCs were used in in vivo animal studies to treat contusion SCIs and that behavioral assessment of locomotor functional recovery was performed using the Basso,Beattie,and Bresnahan lo-comotor rating scale.Exclusion criteria included a follow-up of less than 4 weeks and the lack of control groups.Outcome measures:The restoration of motor function was assessed by the Basso,Beattie,and Bresnahan locomotor rating scale.Results:We identified 1756 non-duplicated papers by searching the aforementioned electronic databases,and 30 full-text articles met the inclusion criteria.A total of 37 studies reported in the 30 articles were included in the meta-analysis.The meta-analysis results showed that transplanted NSCs could improve the motor function recovery of rats following contusion SCIs,to a moderate extent(pooled standardized mean difference(SMD)=0.73;95%confidence interval(CI):0.47–1.00;P<0.001).NSCs obtained from different donor species(rat:SMD=0.74;95%CI:0.36–1.13;human:SMD=0.78;95%CI:0.31–1.25),at different donor ages(fetal:SMD=0.67;95%CI:0.43–0.92;adult:SMD=0.86;95%CI:0.50–1.22)and from different origins(brain-derived:SMD=0.59;95%CI:0.27–0.91;spinal cord-derived:SMD=0.51;95%CI:0.22–0.79)had similar efficacies on improved functional recovery;however,adult induced pluripotent stem cell-derived NSCs showed no significant efficacies.Furthermore,the use of higher doses of transplanted NSCs or the administration of immunosuppressive agents did not promote better locomotor function recovery(SMD=0.45;95%CI:0.21–0.70).However,shorter periods between the contusion induction and the NSC transplantation showed slightly higher efficacies(acute:SMD=1.22;95%CI:0.81–1.63;subacute:SMD=0.75;95%CI:0.42–1.09).For chronic injuries,NSC implantation did not significantly improve functional recovery(SMD=0.25;95%CI:–0.16 to 0.65).Conclusion:NSC transplantation alone appears to be a positive yet limited method for the treatment of contusion SCIs.
基金supported by the National Natural Science Foundation of China,No.61534003(to ZGW),81371663(to XYS)Opening Project of State Key Laboratory of Bioelectronics in Southeast University(to XYS)+2 种基金the“226 Engineering”Research Project of Nantong Government(to XYS)“Six Talent Peaks”Project,No.SWYY-116(to XYS)Postgraduate Research&Practice Innovation Program of Jiangsu Province,No.KYCX18_2424(to CLT)。
文摘Functional electrical stimulation is an effective way to rebuild hindlimb motor function after spinal cord injury.However,no site map exists to serve as a reference for implanting stimulator electrodes.In this study,rat models of thoracic spinal nerve 9 contusion were established by a heavy-impact method and rat models of T6/8/9 spinal cord injury were established by a transection method.Intraspinal microstimulation was performed to record motion types,site coordinates,and threshold currents induced by stimulation.After transection(complete injury),the core region of hip flexion migrated from the T13 to T12 vertebral segment,and the core region of hip extension migrated from the L1 to T13 vertebral segment.Migration was affected by post-transection time,but not transection segment.Moreover,the longer the post-transection time,the longer the distance of migration.This study provides a reference for spinal electrode implantation after spinal cord injury.This study was approved by the Institutional Animal Care and Use Committee of Nantong University,China(approval No.20190225-008)on February 26,2019.
基金Supported by the National Natural Science Foundation of China(61573378)the Fundamental Research Funds for the Central Universities(15CX06064A)
文摘This paper presents an adaptive rationalized Haar function approximation method to obtain the optimal injection strategy for alkali-surfactant-polymer(ASP) flooding. In this process, the non-uniform control vector parameterization is introduced to convert original problem into a multistage optimization problem, in which a new normalized time variable is adopted on the combination of the subinterval length. Then the rationalized Haar function approximation method, in which an auxiliary function is introduced to dispose path constraints, is used to transform the multistage problem into a nonlinear programming. Furthermore, an adaptive strategy proposed on the basis of errors is adopted to regulate the order of Haar function vectors. Finally, the nonlinear programming for ASP flooding is solved by sequential quadratic programming. To illustrate the performance of proposed method,the experimental comparison method and control vector parameterization(CVP) method are introduced to optimize the original problem directly. By contrastive analysis of results, the accuracy and efficiency of proposed method are confirmed.
