·AIM:To determine the effects of protocatechuic acid(PCA)on streptozocin-induced diabetic retinopathy(DR)in rats.·METHODS:Wistar rats were given a 50 mg/kg intraperitoneal injection of streptozocin to induce...·AIM:To determine the effects of protocatechuic acid(PCA)on streptozocin-induced diabetic retinopathy(DR)in rats.·METHODS:Wistar rats were given a 50 mg/kg intraperitoneal injection of streptozocin to induce diabetes.Animals were assigned randomly one of four groups(8 rats per group):control,diabetic,diabetic plus PCA(25 mg/kg·d),and diabetic plus PCA(50 mg/kg·d).After inducing diabetes,treatments were started one week later and continued for eight weeks.After the experiment,the rats were sacrificed,and their retinas were taken for biochemical and molecular analysis.·RESULTS:PCA administration diminished the blood glucose and glycated haemoglobin levels relative to the diabetic group.In diabetic rats,PCA lowered elevated levels of advanced glycosylated end products(AGEs)and receptor for AGEs(RAGE).In the retina of diabetic rats,PCA effectively decreased inflammatory cytokine,nuclear factor-κB,tumour necrosis factor-α,interleukin-1β,and vascular endothelial growth factor,and increased antioxidant markers glutathione,superoxide dismutase,and catalase.·CONCLUSION:The protective benefits of PCA against DR may be attributable to its suppression of the AGEs and RAGE and its antioxidant and anti-inflammatory properties.展开更多
The internal stress field of an inhomogeneous or homogeneous inclusion in an infinite elastic plane under uniform stress-free eigenstrains is studied. The study is restricted to the inclusion shapes defined by the pol...The internal stress field of an inhomogeneous or homogeneous inclusion in an infinite elastic plane under uniform stress-free eigenstrains is studied. The study is restricted to the inclusion shapes defined by the polynomial mapping functions mapping the exterior of the inclusion onto the exterior of a unit circle. The inclusion shapes, giving a polynomial internal stress field, are determined for three types of inclusions, i.e., an inhomogeneous inclusion with an elastic modulus different from the surrounding matrix, an inhomogeneous inclusion with the same shear modulus but a different Poisson's ratio from the surrounding matrix, and a homogeneous inclusion with the same elastic modulus as the surrounding matrix. Examples are presented, and several specific conclusions are achieved for the relation between the degree of the polynomial internal stress field and the degree of the mapping function defining the inclusion shape.展开更多
Modal parameters are of great significance in civil engineering because they can characterize the properties of structures and be used for vibration control and structural health monitoring.Subway tunnels are long lin...Modal parameters are of great significance in civil engineering because they can characterize the properties of structures and be used for vibration control and structural health monitoring.Subway tunnels are long linear truss structures combined with the mutual cou-pling of the surrounding soil.Therefore,the operational modal analysis of a mutual coupling tunnel is complicate,as is the modal iden-tification of shield tunnels in a time–frequency domain,and these are hot civil engineering topics.Using the shield tunnel of Shanghai metro line No.12 project as a case study,we carried out the vibration response monitoring of a subway tunnel during operation and presented methods to identify structural modal parameters.The modal parameters of lower vibration modes were estimated using response measurements.Modal frequencies and shapes were identified with high precision and accuracy using the orthogonal polynomial clustering algorithm under hammer excitation conditions and the autoregressive-moving-average model under ambient excitation con-ditions.The dynamic behavior of a mutual coupling tunnel presented obvious low frequency characteristics,and the first 9th order mode frequencies were less than 100 Hz.The diagonal values of the modal assurance criteria were all greater than 0.85.The modal parameters can be used for the health monitoring of operational subway tunnels.展开更多
Age-related macular degeneration (AMD) is a complex eye disorder and is the leading cause of incurable blindness worldwide in the elderly. Clinically, AMD initially affects the central area of retina known as the macu...Age-related macular degeneration (AMD) is a complex eye disorder and is the leading cause of incurable blindness worldwide in the elderly. Clinically, AMD initially affects the central area of retina known as the macula and it is classified as early stage to late stage (advanced AMD). The advanced AMD is classified into the nonexudative or atrophic form (dry AMD) and the exudative or neovascular form (wet AMD). More severe vision loss is typically associated with the wet form. Multiple genetic factors, lipid metabolism, oxidative stress and aging, play a role in the etiology of AMD. Dysregulation in genetic to AMD is established to 46%–71% of disease contribution, with CFH and ARMS2/HTRA1 to be the two most notable risk loci among the 103 identified AMD associated loci so far. Chronic cigarette smoking is the most proven consistently risk living habits for AMD. Deep learning algorithm has been developed based on image recognition to distinguish wet AMD and normal macula with high accuracy. Currently, anti-vascular endothelial growth factor (VEGF) therapy is highly effective at treating wet AMD. Several new generation AMD drugs and iPSC-derived RPE cell therapy are in the clinical trial stage and are promising to improve AMD treatment in the near future.展开更多
In order to solve the problem of interaction between multiple evaluation indexes of seed metering performance under multiple factors of centralized seed feeding device,a multi-objective optimization of structure based...In order to solve the problem of interaction between multiple evaluation indexes of seed metering performance under multiple factors of centralized seed feeding device,a multi-objective optimization of structure based on particle swarm optimization(PSO)algorithm was proposed in this paper.The wheat centralized seed feeding device was taken as the research object,and the experimental factors were cone angle of type hole,working speed and seed filling gap.The working process of wheat centralized seed feeding device was simulated by discrete element method(DEM).The average seed number of type hole,the variation coefficient of the average seed number of type hole,and the maximum tangential force between seed and seed feeding mechanism were selected as the evaluation indexes.Through the variance analysis of the evaluation indexes by the experimental factors,the optimization objective function was constructed.Using PSO algorithm,the multi-objective optimization was carried out for the wheat centralized seed feeding device.The optimization results show that the best structural combination parameters of the wheat centralized seed feeding device are the hole cone angle of 31.6°and the seed filling gap of 4.6 mm.The validity of the method was verified by simulation and field test.The results show that the PSO algorithm multi-objective optimization method proposed in this paper can provide a reference for the structural improvement and optimal design of the centralized seed feeding device.展开更多
With a successful and rapid development of offshore wind industry and increased research activities on wave energy conversion in recent years,there is an interest in investigating the technological and economic feasib...With a successful and rapid development of offshore wind industry and increased research activities on wave energy conversion in recent years,there is an interest in investigating the technological and economic feasibility of combining offshore wind turbines(WTs)with wave energy converters(WECs).In the EU FP7 MARINA Platform project,three floating combined concepts,namely the spar torus combination(STC),the semi-submersible flap combination(SFC)and the oscillating water column(OWC)array with a wind turbine,were selected and studied in detail by numerical and experimental methods.This paper summarizes the numerical modeling and analysis of the two concepts:STC and SFC,the model tests at a 1:50 scale under simultaneous wave and wind excitation,as well as the comparison between the numerical and experimental results.Both operational and survival wind and wave conditions were considered.The numerical analysis was based on a time-domain global model using potential flow theory for hydrodynamics and blade element momentum theory(for SFC)or simplified thrust force model(for STC)for aerodynamics.Different techniques for model testing of combined wind and wave concepts were discussed with focus on modeling of wind turbines by disk or redesigned small-scale rotor and modeling of power take-off(PTO)system for wave energy conversion by pneumatic damper or hydraulic rotary damper.In order to reduce the uncertainty due to scaling,the numerical analysis was performed at model scale and both the numerical and experimental results were then up-scaled to full scale for comparison.The comparison shows that the current numerical model can well predict the responses(motions,PTO forces,power production)of the combined concepts for most of the cases.However,the linear hydrodynamic model is not adequate for the STC concept in extreme wave conditions with the torus fixed to the spar at the mean water level for which the wave slamming on the torus occurs and this requires further investigation.Moreover,based on a preliminary comparison of the displacement,the PTO system as well as the wind and wave power production,the STC concept will have a lower cost of energy as compared to the SFC concept.However,the cost of energy of either the STC or the SFC concept is higher than that of a pure floating wind turbine with the same floater.展开更多
基金Supported by Model Construction of Regional Prevention and Treatment of Diabetic Retinopathy,Sichuan Science and Technology Support Program (No.2016FZ0091)。
文摘·AIM:To determine the effects of protocatechuic acid(PCA)on streptozocin-induced diabetic retinopathy(DR)in rats.·METHODS:Wistar rats were given a 50 mg/kg intraperitoneal injection of streptozocin to induce diabetes.Animals were assigned randomly one of four groups(8 rats per group):control,diabetic,diabetic plus PCA(25 mg/kg·d),and diabetic plus PCA(50 mg/kg·d).After inducing diabetes,treatments were started one week later and continued for eight weeks.After the experiment,the rats were sacrificed,and their retinas were taken for biochemical and molecular analysis.·RESULTS:PCA administration diminished the blood glucose and glycated haemoglobin levels relative to the diabetic group.In diabetic rats,PCA lowered elevated levels of advanced glycosylated end products(AGEs)and receptor for AGEs(RAGE).In the retina of diabetic rats,PCA effectively decreased inflammatory cytokine,nuclear factor-κB,tumour necrosis factor-α,interleukin-1β,and vascular endothelial growth factor,and increased antioxidant markers glutathione,superoxide dismutase,and catalase.·CONCLUSION:The protective benefits of PCA against DR may be attributable to its suppression of the AGEs and RAGE and its antioxidant and anti-inflammatory properties.
基金Project supported by the National Natural Science Foundation of China(No.11372363)the Fundamental Research Funds for the Central Universities of China(No.0241005202006)+1 种基金the Natural Science&Engineering Research Council of Canadathe Open Research Foundation of the State Key Laboratory of Structural Analysis for Industrial Equipment(No.GZ1404)
文摘The internal stress field of an inhomogeneous or homogeneous inclusion in an infinite elastic plane under uniform stress-free eigenstrains is studied. The study is restricted to the inclusion shapes defined by the polynomial mapping functions mapping the exterior of the inclusion onto the exterior of a unit circle. The inclusion shapes, giving a polynomial internal stress field, are determined for three types of inclusions, i.e., an inhomogeneous inclusion with an elastic modulus different from the surrounding matrix, an inhomogeneous inclusion with the same shear modulus but a different Poisson's ratio from the surrounding matrix, and a homogeneous inclusion with the same elastic modulus as the surrounding matrix. Examples are presented, and several specific conclusions are achieved for the relation between the degree of the polynomial internal stress field and the degree of the mapping function defining the inclusion shape.
基金supported by National Key R&D Program of China(Grant No.2019YFC0605103)National Natural Science Foundation of China(Grant Nos.51978431,52008214)Science and Technology Foundation of Jiangxi Provincial Transportation Department(Grant No.2020Z0003),China.
文摘Modal parameters are of great significance in civil engineering because they can characterize the properties of structures and be used for vibration control and structural health monitoring.Subway tunnels are long linear truss structures combined with the mutual cou-pling of the surrounding soil.Therefore,the operational modal analysis of a mutual coupling tunnel is complicate,as is the modal iden-tification of shield tunnels in a time–frequency domain,and these are hot civil engineering topics.Using the shield tunnel of Shanghai metro line No.12 project as a case study,we carried out the vibration response monitoring of a subway tunnel during operation and presented methods to identify structural modal parameters.The modal parameters of lower vibration modes were estimated using response measurements.Modal frequencies and shapes were identified with high precision and accuracy using the orthogonal polynomial clustering algorithm under hammer excitation conditions and the autoregressive-moving-average model under ambient excitation con-ditions.The dynamic behavior of a mutual coupling tunnel presented obvious low frequency characteristics,and the first 9th order mode frequencies were less than 100 Hz.The diagonal values of the modal assurance criteria were all greater than 0.85.The modal parameters can be used for the health monitoring of operational subway tunnels.
基金This research was supported by the National Natural Science Foundation of China(No.81670895 and 81970839 to L.H.,81700841 to J.L.)the Department of Science and Technology of Sichuan Province,China(No.21ZDYF0551 to L.H2016FZ0091 to Ling Wan).
文摘Age-related macular degeneration (AMD) is a complex eye disorder and is the leading cause of incurable blindness worldwide in the elderly. Clinically, AMD initially affects the central area of retina known as the macula and it is classified as early stage to late stage (advanced AMD). The advanced AMD is classified into the nonexudative or atrophic form (dry AMD) and the exudative or neovascular form (wet AMD). More severe vision loss is typically associated with the wet form. Multiple genetic factors, lipid metabolism, oxidative stress and aging, play a role in the etiology of AMD. Dysregulation in genetic to AMD is established to 46%–71% of disease contribution, with CFH and ARMS2/HTRA1 to be the two most notable risk loci among the 103 identified AMD associated loci so far. Chronic cigarette smoking is the most proven consistently risk living habits for AMD. Deep learning algorithm has been developed based on image recognition to distinguish wet AMD and normal macula with high accuracy. Currently, anti-vascular endothelial growth factor (VEGF) therapy is highly effective at treating wet AMD. Several new generation AMD drugs and iPSC-derived RPE cell therapy are in the clinical trial stage and are promising to improve AMD treatment in the near future.
基金The authors acknowledge that this work was financially supported by Collaborative Innovation Project of Anhui Colleges and Universities(GXXT-2019-036)Nature Science Fund Project of Anhui province(2008085QE217)Natural Science Fund Project of Anhui Agricultural University(2019zd09).
文摘In order to solve the problem of interaction between multiple evaluation indexes of seed metering performance under multiple factors of centralized seed feeding device,a multi-objective optimization of structure based on particle swarm optimization(PSO)algorithm was proposed in this paper.The wheat centralized seed feeding device was taken as the research object,and the experimental factors were cone angle of type hole,working speed and seed filling gap.The working process of wheat centralized seed feeding device was simulated by discrete element method(DEM).The average seed number of type hole,the variation coefficient of the average seed number of type hole,and the maximum tangential force between seed and seed feeding mechanism were selected as the evaluation indexes.Through the variance analysis of the evaluation indexes by the experimental factors,the optimization objective function was constructed.Using PSO algorithm,the multi-objective optimization was carried out for the wheat centralized seed feeding device.The optimization results show that the best structural combination parameters of the wheat centralized seed feeding device are the hole cone angle of 31.6°and the seed filling gap of 4.6 mm.The validity of the method was verified by simulation and field test.The results show that the PSO algorithm multi-objective optimization method proposed in this paper can provide a reference for the structural improvement and optimal design of the centralized seed feeding device.
文摘With a successful and rapid development of offshore wind industry and increased research activities on wave energy conversion in recent years,there is an interest in investigating the technological and economic feasibility of combining offshore wind turbines(WTs)with wave energy converters(WECs).In the EU FP7 MARINA Platform project,three floating combined concepts,namely the spar torus combination(STC),the semi-submersible flap combination(SFC)and the oscillating water column(OWC)array with a wind turbine,were selected and studied in detail by numerical and experimental methods.This paper summarizes the numerical modeling and analysis of the two concepts:STC and SFC,the model tests at a 1:50 scale under simultaneous wave and wind excitation,as well as the comparison between the numerical and experimental results.Both operational and survival wind and wave conditions were considered.The numerical analysis was based on a time-domain global model using potential flow theory for hydrodynamics and blade element momentum theory(for SFC)or simplified thrust force model(for STC)for aerodynamics.Different techniques for model testing of combined wind and wave concepts were discussed with focus on modeling of wind turbines by disk or redesigned small-scale rotor and modeling of power take-off(PTO)system for wave energy conversion by pneumatic damper or hydraulic rotary damper.In order to reduce the uncertainty due to scaling,the numerical analysis was performed at model scale and both the numerical and experimental results were then up-scaled to full scale for comparison.The comparison shows that the current numerical model can well predict the responses(motions,PTO forces,power production)of the combined concepts for most of the cases.However,the linear hydrodynamic model is not adequate for the STC concept in extreme wave conditions with the torus fixed to the spar at the mean water level for which the wave slamming on the torus occurs and this requires further investigation.Moreover,based on a preliminary comparison of the displacement,the PTO system as well as the wind and wave power production,the STC concept will have a lower cost of energy as compared to the SFC concept.However,the cost of energy of either the STC or the SFC concept is higher than that of a pure floating wind turbine with the same floater.