Mesenchymal stem cells(MSCs)have been widely used in regenerative medicine and clinical therapy due to their capabilities of proliferation,differentiation,and immune regulation.However,during in vitro expansion,MSCs a...Mesenchymal stem cells(MSCs)have been widely used in regenerative medicine and clinical therapy due to their capabilities of proliferation,differentiation,and immune regulation.However,during in vitro expansion,MSCs are prone to aging,which largely limits their application.Prostaglandin E-2(PGE-2)is a key effector secreted by MSCs to exert immunomodulatory effects.By screening the compound library for PGE-2 secretion,the antioxidant trolox was verified as a stimulator of MSCs to secrete PGE-2.The effect of antioxidant trolox on biological characteristics of MSCS,including aging,proliferation,and gene expression,was examined.The results demonstrated that trolox can resist aging,promote proliferation,and enhance PGE-2 secretion of MSCs without affecting their surface marker expression.Furthermore,trolox treatment up-regulates miR-17-92 clusters in MSCs and may contribute to its anti-aging effects.Thus,trolox addition might be beneficial for MSCs expansion and their application.展开更多
Drought is one of the main factors limiting the agricultural planting and production;gravel mulching is an effective inhibiting evaporation and water-saving planting pattern in the arid regions. In this study, experim...Drought is one of the main factors limiting the agricultural planting and production;gravel mulching is an effective inhibiting evaporation and water-saving planting pattern in the arid regions. In this study, experiments were conducted to study soil moisture effect and regression model with different gravel mulching, the soil moisture content and evaporation were compared that gravel mulched with different particle sizes, different thickness layer and different mulched years. The results showed that: 1) The cumulative soil evaporation of gravel mulched was only 29.3% of that bare fields. Mulching gravel could significantly reduce soil moisture evaporation. 2) The effects of inhibiting soil moisture evaporation are the best when mulch gravel thickness is 10 - 15 cm. 3) The particle size of gravel mulched is smaller, the evaporation inhibition effect will be better. Considering the water holding capacity and material economy, it is the most suitable to mulch gravel with the particle size of 3 - 5 cm. 4) Mulching gravel on the soil surface for 1 - 3 years can improve the soil moisture content. However, the gravel was mulched for more than five years, the soil moisture content decreased significantly. 5) The quadratic polynomial regression fitting model can better simulate and predict the cumulative evaporation on different gravel mulched, and the regression fitting degree R<sup>2</sup> is more than 0.98.展开更多
In order to monitor and forecast the deformation of the brick-concrete building, by taking a brick-concrete building as research object, fiber grating sensors were used to collect the monitoring data and double logari...In order to monitor and forecast the deformation of the brick-concrete building, by taking a brick-concrete building as research object, fiber grating sensors were used to collect the monitoring data and double logarithmic curve of limit value characteristic and monitoring data were obtained based on the fractal theory. Constant dimension fractal method cannot be used to analyze the data directly. With the method of variable dimension fractal, we accumulate data, and the double logarithmic curve is smooth. Piecewise fractal dimensions are close. The outer interpolation method is used to calculate the fractal dimension of the next point and then back calculate the vertical displacement. The relative errors are calculated by comparing the forecast values and monitoring values, and the maximum relative error is 5.76%. The result shows that the fractal theory is suitable to use in the forecast of the deformation and the accuracy is good.展开更多
Gully erosion is a disruptive phenomenon which extensively affects the Iranian territory,especially in the Northern provinces.A number of studies have been recently undertaken to study this process and to predict it o...Gully erosion is a disruptive phenomenon which extensively affects the Iranian territory,especially in the Northern provinces.A number of studies have been recently undertaken to study this process and to predict it over space and ultimately,in a broader national effort,to limit its negative effects on local communities.We focused on the Bastam watershed where 9.3%of its surface is currently affected by gullying.Machine learning algorithms are currently under the magnifying glass across the geomorphological community for their high predictive ability.However,unlike the bivariate statistical models,their structure does not provide intuitive and quantifiable measures of environmental preconditioning factors.To cope with such weakness,we interpret preconditioning causes on the basis of a bivariate approach namely,Index of Entropy.And,we performed the susceptibility mapping procedure by testing three extensions of a decision tree model namely,Alternating Decision Tree(ADTree),Naive-Bayes tree(NBTree),and Logistic Model Tree(LMT).We dichotomized the gully information over space into gully presence/absence conditions,which we further explored in their calibration and validation stages.Being the presence/absence information and associated factors identical,the resulting differences are only due to the algorithmic structures of the three models we chose.Such differences are not significant in terms of performances;in fact,the three models produce outstanding predictive AUC measures(ADTree=0.922;NBTree=0.939;LMT=0.944).However,the associated mapping results depict very different patterns where only the LMT is associated with reasonable susceptibility patterns.This is a strong indication of what model combines best performance and mapping for any natural hazard-oriented application.展开更多
Epoxy resin powder coating has been successfully applied on the corrosion protection of magnesium lithium alloys.However,poor wear resistance and microcracks formed during the solidification have limited it extensive ...Epoxy resin powder coating has been successfully applied on the corrosion protection of magnesium lithium alloys.However,poor wear resistance and microcracks formed during the solidification have limited it extensive application.There are limited approaches to exploit such anti-corrosion and mechanical properties of magnesium lithium alloys.Herein,the epoxy resin powder coating with polydopamine modified molybdenum disulfide(MoS_(2)@PDA-EP powder coating with 0,0.1,0.2,0.5,1.0 wt.%loading)was well prepared by melt extrusion to investigate its anticorrosion performance and wear resistance.The results revealed that the addition of MoS_(2)@PDA enhanced the adhesion strength between coatings and alloys,wear resistance and corrosion protection of the powder coatings.Among them,the optimum was obtained by 0.2 wt.%MoS_(2)@PDA-EP powder coating which could be attributed to well dispersion and efficient adhesion with coating matrix.To conclude,MoS_(2)@PDA-EP powder coating is meaningfully beneficial for the anticorrosive and wear performance improvement of magnesium lithium alloys.展开更多
Natural gas hydrate inhibitor has been serving the oil and gas industry for many years. The development and search for new inhibitors remain the focus of research. In this study, the solution polymerization method was...Natural gas hydrate inhibitor has been serving the oil and gas industry for many years. The development and search for new inhibitors remain the focus of research. In this study, the solution polymerization method was employed to prepare poly(N-vinyl caprolactam-co-butyl methacrylate)(P(VCap-BMA)), as a new kinetic hydrate inhibitor(KHI). The inhibition properties of P(VCap-BMA) were investigated by tetrahydrofuran(THF) hydrate testing and natural gas hydrate forming and compared with the commercial KHIs. The experiment showed that PVCap performed better than copolymer P(VCap-BMA). However,low doses of methanol or ethylene glycol are compounded with KHIs. The compounding inhibitors show a synergistic inhibitory effect. More interesting is the P(VCap-BMA)-methanol system has a better inhibitory effect than the PVCap-methanol system. 1% P(VCap-BMA) + 5% methanol presented the best inhibiting performance at subcooling 10.3 °C, the induction time of natural gas hydrate was 445 min.Finally, the interaction between water and several dimeric inhibitors compared by natural bond orbital(NBO) analyses and density functional theory(DFT) indicated that inhibitor molecules were able to form the hydrogen bond with the water molecules, which result in gas hydrate inhibition. These exciting properties make the P(VCap-BMA) compound hydrate inhibitor promising candidates for numerous applications in the petrochemical industry.展开更多
The relationships between the tropical Indian Ocean basin （IOB）/dipole （IOD） mode of SST anomalies （SSTAs） and ENSO phase transition during the following year are examined and compared in observations for the pe...The relationships between the tropical Indian Ocean basin （IOB）/dipole （IOD） mode of SST anomalies （SSTAs） and ENSO phase transition during the following year are examined and compared in observations for the period 1958-2008. Both partial correlation analysis and composite analysis show that both the positive （negative） phase of the lOB and IOD （independent of each other） in the tropical Indian Ocean are possible contributors to the E1 Nino （La Nifia） decay and phase transition to La Nifia （El Nifio） about one year later. However, the influence on ENSO transition induced by the IOB is stronger than that by the IOD. The SSTAs in the equatorial central-eastern Pacific in the coming year originate from subsurface temperature anomalies in the equatorial eastern Indian and western Pacific Ocean, induced by the IOB and IOD through eastward and upward propagation to meet the surface. During this process, however the contribution of the oceanic channel process between the tropical Indian and Pacific oceans is totally different for the IOB and IOD. For the IOD, the influence of the Indonesian Throughflow transport anomalies could propagate to the eastern Pacific to induce the ENSO transition. For the IOB, the impact of the oceanic channel stays and disappears in the western Pacific without propagation to the eastern Pacific.展开更多
The health monitoring for large-scale structures need to resolve a large number of difficulties,such as the data transmission and distributing information handling.To solve these problems,the technology of multi-agent...The health monitoring for large-scale structures need to resolve a large number of difficulties,such as the data transmission and distributing information handling.To solve these problems,the technology of multi-agent is a good candidate to be used in the field of structural health monitoring.A structural health monitoring system architecture based on multi-agent technology is proposed.The measurement system for aircraft airfoil is designed with FBG,strain gage,and corresponding signal processing circuit.The experiment to determine the location of the concentrate loading on the structure is carried on with the system combined with technologies of pattern recognition and multi-agent.The results show that the system can locate the concentrate loading of the aircraft airfoil at the accuracy of 91.2%.展开更多
基金supported by the Natural Science Foundation of Shandong Province(ZR2020MH327)Hebei Key Research and Development Program(19272405D)Jilin Scientific and Technological Development Program(Grant No.20190304041YY).
文摘Mesenchymal stem cells(MSCs)have been widely used in regenerative medicine and clinical therapy due to their capabilities of proliferation,differentiation,and immune regulation.However,during in vitro expansion,MSCs are prone to aging,which largely limits their application.Prostaglandin E-2(PGE-2)is a key effector secreted by MSCs to exert immunomodulatory effects.By screening the compound library for PGE-2 secretion,the antioxidant trolox was verified as a stimulator of MSCs to secrete PGE-2.The effect of antioxidant trolox on biological characteristics of MSCS,including aging,proliferation,and gene expression,was examined.The results demonstrated that trolox can resist aging,promote proliferation,and enhance PGE-2 secretion of MSCs without affecting their surface marker expression.Furthermore,trolox treatment up-regulates miR-17-92 clusters in MSCs and may contribute to its anti-aging effects.Thus,trolox addition might be beneficial for MSCs expansion and their application.
文摘Drought is one of the main factors limiting the agricultural planting and production;gravel mulching is an effective inhibiting evaporation and water-saving planting pattern in the arid regions. In this study, experiments were conducted to study soil moisture effect and regression model with different gravel mulching, the soil moisture content and evaporation were compared that gravel mulched with different particle sizes, different thickness layer and different mulched years. The results showed that: 1) The cumulative soil evaporation of gravel mulched was only 29.3% of that bare fields. Mulching gravel could significantly reduce soil moisture evaporation. 2) The effects of inhibiting soil moisture evaporation are the best when mulch gravel thickness is 10 - 15 cm. 3) The particle size of gravel mulched is smaller, the evaporation inhibition effect will be better. Considering the water holding capacity and material economy, it is the most suitable to mulch gravel with the particle size of 3 - 5 cm. 4) Mulching gravel on the soil surface for 1 - 3 years can improve the soil moisture content. However, the gravel was mulched for more than five years, the soil moisture content decreased significantly. 5) The quadratic polynomial regression fitting model can better simulate and predict the cumulative evaporation on different gravel mulched, and the regression fitting degree R<sup>2</sup> is more than 0.98.
文摘In order to monitor and forecast the deformation of the brick-concrete building, by taking a brick-concrete building as research object, fiber grating sensors were used to collect the monitoring data and double logarithmic curve of limit value characteristic and monitoring data were obtained based on the fractal theory. Constant dimension fractal method cannot be used to analyze the data directly. With the method of variable dimension fractal, we accumulate data, and the double logarithmic curve is smooth. Piecewise fractal dimensions are close. The outer interpolation method is used to calculate the fractal dimension of the next point and then back calculate the vertical displacement. The relative errors are calculated by comparing the forecast values and monitoring values, and the maximum relative error is 5.76%. The result shows that the fractal theory is suitable to use in the forecast of the deformation and the accuracy is good.
文摘Gully erosion is a disruptive phenomenon which extensively affects the Iranian territory,especially in the Northern provinces.A number of studies have been recently undertaken to study this process and to predict it over space and ultimately,in a broader national effort,to limit its negative effects on local communities.We focused on the Bastam watershed where 9.3%of its surface is currently affected by gullying.Machine learning algorithms are currently under the magnifying glass across the geomorphological community for their high predictive ability.However,unlike the bivariate statistical models,their structure does not provide intuitive and quantifiable measures of environmental preconditioning factors.To cope with such weakness,we interpret preconditioning causes on the basis of a bivariate approach namely,Index of Entropy.And,we performed the susceptibility mapping procedure by testing three extensions of a decision tree model namely,Alternating Decision Tree(ADTree),Naive-Bayes tree(NBTree),and Logistic Model Tree(LMT).We dichotomized the gully information over space into gully presence/absence conditions,which we further explored in their calibration and validation stages.Being the presence/absence information and associated factors identical,the resulting differences are only due to the algorithmic structures of the three models we chose.Such differences are not significant in terms of performances;in fact,the three models produce outstanding predictive AUC measures(ADTree=0.922;NBTree=0.939;LMT=0.944).However,the associated mapping results depict very different patterns where only the LMT is associated with reasonable susceptibility patterns.This is a strong indication of what model combines best performance and mapping for any natural hazard-oriented application.
基金financial support provided by the National Natural Science Foundation of China(Grant No.U1806225)the National Natural Science Foundation of China(Grant No.51908092)the Joint Funds of the National Natural Science Foundation of China-Guangdong(Grant No.U1801254)。
文摘Epoxy resin powder coating has been successfully applied on the corrosion protection of magnesium lithium alloys.However,poor wear resistance and microcracks formed during the solidification have limited it extensive application.There are limited approaches to exploit such anti-corrosion and mechanical properties of magnesium lithium alloys.Herein,the epoxy resin powder coating with polydopamine modified molybdenum disulfide(MoS_(2)@PDA-EP powder coating with 0,0.1,0.2,0.5,1.0 wt.%loading)was well prepared by melt extrusion to investigate its anticorrosion performance and wear resistance.The results revealed that the addition of MoS_(2)@PDA enhanced the adhesion strength between coatings and alloys,wear resistance and corrosion protection of the powder coatings.Among them,the optimum was obtained by 0.2 wt.%MoS_(2)@PDA-EP powder coating which could be attributed to well dispersion and efficient adhesion with coating matrix.To conclude,MoS_(2)@PDA-EP powder coating is meaningfully beneficial for the anticorrosive and wear performance improvement of magnesium lithium alloys.
基金supported by the Key Science and Technology Program of Shaanxi Province (2014K10-03)。
文摘Natural gas hydrate inhibitor has been serving the oil and gas industry for many years. The development and search for new inhibitors remain the focus of research. In this study, the solution polymerization method was employed to prepare poly(N-vinyl caprolactam-co-butyl methacrylate)(P(VCap-BMA)), as a new kinetic hydrate inhibitor(KHI). The inhibition properties of P(VCap-BMA) were investigated by tetrahydrofuran(THF) hydrate testing and natural gas hydrate forming and compared with the commercial KHIs. The experiment showed that PVCap performed better than copolymer P(VCap-BMA). However,low doses of methanol or ethylene glycol are compounded with KHIs. The compounding inhibitors show a synergistic inhibitory effect. More interesting is the P(VCap-BMA)-methanol system has a better inhibitory effect than the PVCap-methanol system. 1% P(VCap-BMA) + 5% methanol presented the best inhibiting performance at subcooling 10.3 °C, the induction time of natural gas hydrate was 445 min.Finally, the interaction between water and several dimeric inhibitors compared by natural bond orbital(NBO) analyses and density functional theory(DFT) indicated that inhibitor molecules were able to form the hydrogen bond with the water molecules, which result in gas hydrate inhibition. These exciting properties make the P(VCap-BMA) compound hydrate inhibitor promising candidates for numerous applications in the petrochemical industry.
基金jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA11010102)the NSFC (Grant Nos. 41375094 and 41406028)+1 种基金the "973" project (Grant No. 2012CB956000)the NSFC–Shandong Joint Fund for Marine Science Research Centers (Grant No. U1406401)
文摘The relationships between the tropical Indian Ocean basin （IOB）/dipole （IOD） mode of SST anomalies （SSTAs） and ENSO phase transition during the following year are examined and compared in observations for the period 1958-2008. Both partial correlation analysis and composite analysis show that both the positive （negative） phase of the lOB and IOD （independent of each other） in the tropical Indian Ocean are possible contributors to the E1 Nino （La Nifia） decay and phase transition to La Nifia （El Nifio） about one year later. However, the influence on ENSO transition induced by the IOB is stronger than that by the IOD. The SSTAs in the equatorial central-eastern Pacific in the coming year originate from subsurface temperature anomalies in the equatorial eastern Indian and western Pacific Ocean, induced by the IOB and IOD through eastward and upward propagation to meet the surface. During this process, however the contribution of the oceanic channel process between the tropical Indian and Pacific oceans is totally different for the IOB and IOD. For the IOD, the influence of the Indonesian Throughflow transport anomalies could propagate to the eastern Pacific to induce the ENSO transition. For the IOB, the impact of the oceanic channel stays and disappears in the western Pacific without propagation to the eastern Pacific.
基金supported by the Key Program of the National Science Foundation of China(50830201)Aviation Research Foundation(20060952)+1 种基金the National High Technology Research and Development of China(2007AA03Z117)the Natural Science Foundation of Jiansu Province(08kjd560009)
文摘The health monitoring for large-scale structures need to resolve a large number of difficulties,such as the data transmission and distributing information handling.To solve these problems,the technology of multi-agent is a good candidate to be used in the field of structural health monitoring.A structural health monitoring system architecture based on multi-agent technology is proposed.The measurement system for aircraft airfoil is designed with FBG,strain gage,and corresponding signal processing circuit.The experiment to determine the location of the concentrate loading on the structure is carried on with the system combined with technologies of pattern recognition and multi-agent.The results show that the system can locate the concentrate loading of the aircraft airfoil at the accuracy of 91.2%.
