AIM： To study the effects of extract from Ginkgo biloba （EGb） containing 22% flavonoid and 5% terpenoid on chronic liver injury and liver fibrosis of rats induced by carbon tetrachloride （CCh）. METHODS： All rats...AIM： To study the effects of extract from Ginkgo biloba （EGb） containing 22% flavonoid and 5% terpenoid on chronic liver injury and liver fibrosis of rats induced by carbon tetrachloride （CCh）. METHODS： All rats were randomly divided into control group, CCl4-treated group, colchicine-treated group and EGb-protected group. Chronic liver injury was induced in experimental groups by subcutaneous injection of CCh and fed with chows premixed with 79.5% corn powder, 20% lard and 0.5% cholesterol （v/v）. EGb-protected group was treated with EGb （0.5 g/kg body weight per day） for 7 wk. At the end of wk 8, all the rats were killed. Liver function, liver fibrosis, oxidative stress and expression of transforming growth factor β1 （TGF-β1） a-smooth muscle actin （α-SMA） and type I collagens in liver were determined. In addition, pathology changes of liver tissue were observed under light microscope. RESULTS： The levels of alanine aminotransferase （ALT）, aspartate aminotransferase （AST） and albumin （AIb） in EGb-protected group were notably improved as compared with the CCL4-treated group （P 〈 0.01）. The contents of serum hyaluronic acid （HA）, type III procollagen （PCⅢ）, type IV collagen （CIV） and the expression of hepatic tissue TGF-β1, α-SMA and type I collagen in EGb-protected group were significantly lower than those in CCL4-treated groups （P 〈 0.05, P 〈 0.01）. The degrees of liver fibrosis in EGb-protected groups were lower than those in CCL4-treated groups （6.58 ±1.25 vs 9.52 ± 2.06, P 〈 0.05）. Compared to the CCL4-treated group, the levels of plasma glutathoine peroxidase （Se-GSH-Px）, superoxide dismutase （SOD） and malondialdehyde （MDA） were strikingly improved also in EGb-protected group （P 〈 0.05, P 〈 0.01）. CONCLUSION： EGb resists oxidative stress and thereby reduces chronic liver injury and liver fibrosis in rats with liver injury induced by CCl4.展开更多
Utilizing the acoustic emission(AE) technique, an experimental investigation into the damage evolution for steel strand under axial tension was described. The damage evolution model for steel stand relating the damage...Utilizing the acoustic emission(AE) technique, an experimental investigation into the damage evolution for steel strand under axial tension was described. The damage evolution model for steel stand relating the damage evolution to acoustic emission parameters was proposed by incorporating the AE rate process theory. The AE monitoring results indicate that damages occur in both elastic and plastic phases of steel strand. In elastic phase, AE signals are mainly sent out from the micro damage due to the surface friction among the wires of steel strand, while in plastic phase, AE signals emitted from the plastic deformation of wires. In addition, the AE cumulative parameters curves closely resemble the loading curve. The AE cumulative parameters curves can well describe the damage evolution process including the damage occurrence and damage development for steel strands. It is concluded that the AE technique is an effective and useful nondestructive technique for evaluating the damage characteristics of steel strand.展开更多
In this study,the micro-failure process and failure mechanism of a typical brittle rock under uniaxial compression are investigated via continuous real-time measurement of wave velocities.The experimental results indi...In this study,the micro-failure process and failure mechanism of a typical brittle rock under uniaxial compression are investigated via continuous real-time measurement of wave velocities.The experimental results indicate that the evolutions of wave velocities became progressively anisotropic under uniaxial loading due to the direction-dependent development of micro-damage.A wave velocity model considering the inner anisotropic crack evolution is proposed to accurately describe the variations of wave velocities during uniaxial compression testing.Based on which,the effective elastic parameters are inferred by a transverse isotropic constitutive model,and the evolutions of the crack density are inversed using a self-consistent damage model.It is found that the propagation of axial cracks dominates the failure process of brittle rock under uniaxial loading and oblique shear cracks develop with the appearance of macrocrack.展开更多
Rock pillar is the key supporting component in underground engineering.During an earthquake,the key rock pillar must bear both the seismic load and the load transferred from other damaged pillars.This paper attempts t...Rock pillar is the key supporting component in underground engineering.During an earthquake,the key rock pillar must bear both the seismic load and the load transferred from other damaged pillars.This paper attempts to reveal the influence of the mainshock on damage evolution and failure characteristic of the key rock pillar during aftershocks by cyclic loading test of marble.Four levels of pre-damage stress(i.e.,10,30,50 and 70 MPa)in the first cycle were used to simulate the mainshock damage,and then cyclic stress with the same amplitude(namely 10 MPa)was conducted in the subsequent cycles to simulate the aftershock until rock failure.The results indicate that the presence of pre-damage has an obvious weakening effect on the bearing capacity and deformation resistance of rock materials during the aftershock process.Besides,the increase of pre-damage significantly changes the final failure pattern of the key rock pillar,and leads to an increase in the proportion of small-scale rock fragments.This study may contribute to understanding the seismic capacity of the unreinforced rock pillar during mainshock-aftershock seismic sequences and to optimizing the design of the key rock pillar in underground engineering.展开更多
Trauma-induced coagulopathy （TIC） is a clinical syndrome caused by imbalance between clotting, anti- coagulation and fibrinolysis resulting from multiple pathological factors such as hemorrhage and tissue injury in ...Trauma-induced coagulopathy （TIC） is a clinical syndrome caused by imbalance between clotting, anti- coagulation and fibrinolysis resulting from multiple pathological factors such as hemorrhage and tissue injury in the early stage of trauma, and is closely related to the outcome of trauma patients. It is proved in growing evidence that the endogenous coagulation disturbance in trauma itself is the activating factor of TIC, rather than dilution or other acquired coagulopathy. Therefore, a thorough understanding of the molecular mechanisms in the pathogenesis and progression is crucial for effective prevention and treatment in patients with TIC. This review focuses on transitions in the concept of TIC and mechanical progress.展开更多
文摘AIM： To study the effects of extract from Ginkgo biloba （EGb） containing 22% flavonoid and 5% terpenoid on chronic liver injury and liver fibrosis of rats induced by carbon tetrachloride （CCh）. METHODS： All rats were randomly divided into control group, CCl4-treated group, colchicine-treated group and EGb-protected group. Chronic liver injury was induced in experimental groups by subcutaneous injection of CCh and fed with chows premixed with 79.5% corn powder, 20% lard and 0.5% cholesterol （v/v）. EGb-protected group was treated with EGb （0.5 g/kg body weight per day） for 7 wk. At the end of wk 8, all the rats were killed. Liver function, liver fibrosis, oxidative stress and expression of transforming growth factor β1 （TGF-β1） a-smooth muscle actin （α-SMA） and type I collagens in liver were determined. In addition, pathology changes of liver tissue were observed under light microscope. RESULTS： The levels of alanine aminotransferase （ALT）, aspartate aminotransferase （AST） and albumin （AIb） in EGb-protected group were notably improved as compared with the CCL4-treated group （P 〈 0.01）. The contents of serum hyaluronic acid （HA）, type III procollagen （PCⅢ）, type IV collagen （CIV） and the expression of hepatic tissue TGF-β1, α-SMA and type I collagen in EGb-protected group were significantly lower than those in CCL4-treated groups （P 〈 0.05, P 〈 0.01）. The degrees of liver fibrosis in EGb-protected groups were lower than those in CCL4-treated groups （6.58 ±1.25 vs 9.52 ± 2.06, P 〈 0.05）. Compared to the CCL4-treated group, the levels of plasma glutathoine peroxidase （Se-GSH-Px）, superoxide dismutase （SOD） and malondialdehyde （MDA） were strikingly improved also in EGb-protected group （P 〈 0.05, P 〈 0.01）. CONCLUSION： EGb resists oxidative stress and thereby reduces chronic liver injury and liver fibrosis in rats with liver injury induced by CCl4.
基金Projects(51308073,51378081)supported by the National Natural Science Foundation of ChinaProject(20124316120002)supported by PhD Programs Foundation of Ministry of Education of China+1 种基金Project(12KB02)supported by the Key Laboratory for Safety Control of Bridge Engineering of Ministry of Education of ChinaProject(14JJ3087)supported by the Science Foundation of Hunan Province,China
文摘Utilizing the acoustic emission(AE) technique, an experimental investigation into the damage evolution for steel strand under axial tension was described. The damage evolution model for steel stand relating the damage evolution to acoustic emission parameters was proposed by incorporating the AE rate process theory. The AE monitoring results indicate that damages occur in both elastic and plastic phases of steel strand. In elastic phase, AE signals are mainly sent out from the micro damage due to the surface friction among the wires of steel strand, while in plastic phase, AE signals emitted from the plastic deformation of wires. In addition, the AE cumulative parameters curves closely resemble the loading curve. The AE cumulative parameters curves can well describe the damage evolution process including the damage occurrence and damage development for steel strands. It is concluded that the AE technique is an effective and useful nondestructive technique for evaluating the damage characteristics of steel strand.
基金Projects(41502283,41772309)supported by the National Natural Science Foundation of ChinaProject(2017YFC1501302)supported by the National Key Research and Development Program of ChinaProject(2017ACA102)supported by the Major Program of Technological Innovation of Hubei Province,China。
文摘In this study,the micro-failure process and failure mechanism of a typical brittle rock under uniaxial compression are investigated via continuous real-time measurement of wave velocities.The experimental results indicate that the evolutions of wave velocities became progressively anisotropic under uniaxial loading due to the direction-dependent development of micro-damage.A wave velocity model considering the inner anisotropic crack evolution is proposed to accurately describe the variations of wave velocities during uniaxial compression testing.Based on which,the effective elastic parameters are inferred by a transverse isotropic constitutive model,and the evolutions of the crack density are inversed using a self-consistent damage model.It is found that the propagation of axial cracks dominates the failure process of brittle rock under uniaxial loading and oblique shear cracks develop with the appearance of macrocrack.
基金Project(2022MD713784) supported by China Postdoctoral ScienceProject (1960321032) supported by the Research Start-up Fund Project for High-level Talents Introduction,ChinaProject (1609722058) supported by Xi’ an University of Architecture and Technology,China。
文摘Rock pillar is the key supporting component in underground engineering.During an earthquake,the key rock pillar must bear both the seismic load and the load transferred from other damaged pillars.This paper attempts to reveal the influence of the mainshock on damage evolution and failure characteristic of the key rock pillar during aftershocks by cyclic loading test of marble.Four levels of pre-damage stress(i.e.,10,30,50 and 70 MPa)in the first cycle were used to simulate the mainshock damage,and then cyclic stress with the same amplitude(namely 10 MPa)was conducted in the subsequent cycles to simulate the aftershock until rock failure.The results indicate that the presence of pre-damage has an obvious weakening effect on the bearing capacity and deformation resistance of rock materials during the aftershock process.Besides,the increase of pre-damage significantly changes the final failure pattern of the key rock pillar,and leads to an increase in the proportion of small-scale rock fragments.This study may contribute to understanding the seismic capacity of the unreinforced rock pillar during mainshock-aftershock seismic sequences and to optimizing the design of the key rock pillar in underground engineering.
文摘Trauma-induced coagulopathy （TIC） is a clinical syndrome caused by imbalance between clotting, anti- coagulation and fibrinolysis resulting from multiple pathological factors such as hemorrhage and tissue injury in the early stage of trauma, and is closely related to the outcome of trauma patients. It is proved in growing evidence that the endogenous coagulation disturbance in trauma itself is the activating factor of TIC, rather than dilution or other acquired coagulopathy. Therefore, a thorough understanding of the molecular mechanisms in the pathogenesis and progression is crucial for effective prevention and treatment in patients with TIC. This review focuses on transitions in the concept of TIC and mechanical progress.
