The process of preparing anodic oxide film containing active sites and electroless nickel plating on highly active rare earth magnesium alloy was developed.The formation mechanism of electroless nickel plating on acti...The process of preparing anodic oxide film containing active sites and electroless nickel plating on highly active rare earth magnesium alloy was developed.The formation mechanism of electroless nickel plating on active anodic oxide film and the structure and properties of the composite coating were studied by several surface and electrochemical techniques.The results showed that Ag nanograins with an average size of 10 nm were embedded into the anodic oxide film with pores of 0.1−2μm.Ag nanoparticles provided a catalytic site for the deposition of Ni-B alloy,and the Ni crystal nucleus was first grown in horizontal mode and then in cylindrical mode.The corrosion potential of the composite coating increased by 1.37 V and the corrosion current reduced two orders of magnitude due to the subsequent deposition of Ni-P alloy.The high corrosion resistance was attributed to the misaligning of these micro defects in the three different layers and the amorphous structure of the Ni-P alloy in the outer layer.These findings provide a new idea for electroless nickel plating on anodic oxide film.展开更多
The antidepressive effect of Xiaoyaosan is doubtless by researches while the potential antidepressive ac- tive ingredients and their mechanisms remain unclear. In order to explain the antidepressive effect of Xiaoyaos...The antidepressive effect of Xiaoyaosan is doubtless by researches while the potential antidepressive ac- tive ingredients and their mechanisms remain unclear. In order to explain the antidepressive effect of Xiaoyaosan, all of the recent reports were sought out on the current situation of the antidepressive monomer compositions of Xi- aoyaosan and their mechanism. By exploring the relationship between the effects and the active ingredients, the mechanism and the active ingredients, the antidepressive active ingredients such as quercetin, isorhamnetin, isoliquiritigenin, saikosaponinA, saikosaponinD, glycyrrhiz- kaempferol, liquiritin, isoliquiritin, liquiritigenin, inate, paeoniflorin, albiflorin, ferulic acid, curcumin and their mechanism of antidepressive such as regulating the monoamine neurotransmitter systems, regulating the neuroendocrine system, affecting the neural plasticity and neu- affecting the cytokines level, anti-oxidative stress were rotrophic, affecting the cellular and molecular mechanisms , summarized. By the overview in the level of monomer rather than formulae, we uncovered the antidepressive mech- anism of Xiaoyaosan and further confirmed that Xiaoyaosan, as a classic antidepressive Chinese prescription, had many characteristics, such as multi-level , multi-channel, multi-target and so on .展开更多
Based on physicochemical study of the reaction between scheelite and NaOH, a new decomposition process for scheelite and scheelitewolframite concentrate, i. e., mechenically activating caustic decomposition has bee...Based on physicochemical study of the reaction between scheelite and NaOH, a new decomposition process for scheelite and scheelitewolframite concentrate, i. e., mechenically activating caustic decomposition has been developed, and it has been successfu展开更多
The micromation and precision of the Micro-Electromechanical System demand that its manufacturing, measuring and assembling must work in a micro-manufacturing platform with good ability to isolate vibrations. This pap...The micromation and precision of the Micro-Electromechanical System demand that its manufacturing, measuring and assembling must work in a micro-manufacturing platform with good ability to isolate vibrations. This paper develops a vibration isolation system of micro-manufacturing platform. The brains of many kinds of birds can isolate vibrations well, such as woodpecker’s brain. When a woodpecker pecks the wood at the speed as 1.6 times as the velocity of sound, its brain will tolerate the wallop 1 500 times of the weight of itself without any damage. The isolation mechanics and organic texture of woodpecker’s brain that has good isolation characteristics were studied. A structure model of vibration isolation system for the micro-manufacturing platform is established based on the bionics of the bird’s brain vibration isolation mechanism. In order to isolate effectively the high frequency vibrations from the ground, a rubber layer is used to isolate vibrations passively between the micro-manufacturing platform’s pedestal and the ground. This layer corresponds to the cartilage and muscles in the outer meninges of the bird’s brain. The active vibration isolation technique is adopted to isolate vibrations between the micro-manufacturing platform and the pedestal. Air springs are used as elastic components, which correspond to the interspaces between the outer meninges and the encephala of the bird’s brain. Actuators are made of giant magnetostrictive material, and it corresponds to the nerves and neural muscles linking the meninges and the encephala. The actuators and air springs are arranged vertically in parallel to make use of the giant magnetostrictive actuators effectively. The air springs support almost all weight of the micro-manufacturing platform and the giant magnetostrictive actuators support almost no weight. In order to realize high performance to isolate complex micro-vibration, the control method using a three-layer neural network is presented. This vibration control system takes into account the floor disturbance and the direct disturbance acting on the micro-manufacturing platform. The absolute acceleration of the micro-manufacturing platform is used as the performance index of vibration control. The performance of the control system is tested by numerical simulation. Simulation results show that the active vibration isolation system has good isolation performance against the floor disturbance and the direct disturbance acting on the micro-manufacturing platform in all the frequency range.展开更多
Natural minerals receive growing attention as inexpensive, green, and efficient catalysts for degradation of organic pollutants. Mechanical activation of natural chalcopyrite was conducted for improving the catalytic ...Natural minerals receive growing attention as inexpensive, green, and efficient catalysts for degradation of organic pollutants. Mechanical activation of natural chalcopyrite was conducted for improving the catalytic performance.Tetracycline degradation was evaluated in the presence of hydrogen peroxide and mechanically activated chalcopyrite.Tetracycline degradation at 100 min is 55.52%(Chp10), 68.97%(Chp30), 77.79%(Chp60), and 86.43%(Chp120),respectively, and the rate constant of pseudo-first-order kinetics is 0.0079, 0.0109, 0.0137 and 0.0192 min^(-1), respectively.Chalcopyrite samples were examined by multiple characterizations. Mechanical activation of natural chalcopyrite induces the decline of particle size and slight increase of surface area, smaller grain size, lattice strain, and partial sulfur oxidation. The relationship between catalytic activity and property change manifests that the improved catalytic ability is mainly ascribed to the increase of surface area and surface oxidation induced by mechanical activation. This work provides novel insights into the improvement of catalytic performance of natural minerals by mechanical activation.展开更多
Leaching of lowgrade refractory tungsten ore was carried out through mechanical activation. The effect of temperature, amount of Na2CO3, addition of NaOH, ratio of liquid to solid and leaching time on the recovery of ...Leaching of lowgrade refractory tungsten ore was carried out through mechanical activation. The effect of temperature, amount of Na2CO3, addition of NaOH, ratio of liquid to solid and leaching time on the recovery of WO3 was studied. The WO3 recovery upto 96%～99% has been achieved when the tungsten ore was digested by soda not more than three times stiochiometric amount at 185～195 ℃ for 10～20 h. The WO3 recovery can increase 10%～15% compared to that of conventional soda autoclave process.展开更多
The purpose of this study was to examine the sedimentary facies characteristics of lower Cambrian Niutitang Formation(∈1n)in South China,to reveal the mechanism of organic matter enrichment,and to guide exploration o...The purpose of this study was to examine the sedimentary facies characteristics of lower Cambrian Niutitang Formation(∈1n)in South China,to reveal the mechanism of organic matter enrichment,and to guide exploration of shale gas.Macro investigation and experimental analyses were used to assess the lithology in detail,total organic matter mass fraction w(TOC),mineral composition,and trace element characteristics of∈1n.The influencing factors of organic matter enrichment were discussed extensively,and a sedimentary facies mode was suggested.In the early stage of∈1n,the locations of Well E’yangye 1,Well Ciye 1,Well Changye 1,and Well Anye 1 respectively develop,platform inner sag,outer shelf,Jiangnan slope belt,and South China detention basin.In the late stage of∈1n,the sedimentary facies evolve with decreasing sea level.The study area presents a complete three-step basin in the Early Cambrian.In the early stage of∈1n,the first step is the Yangtze carbonate platform,the second step is the outer shelf and slope,and the third step is the deep-water basin.From the Yangtze carbonate platform to the deep-water basin,w(TOC)and the mass fraction of quartz gradually increase,the mass fraction of carbonate mineral decreases,and the mass fraction of clay mineral is higher in the second step.The sea level fluctuation results in a higher w(TOC)vertically in the lower∈1n shale,and the paleogeographic(provenance)conditions lead to better horizontal development of organic matter in the outer shelf,slope and detention basin.Trace elements are abundant in the lower∈1n,and w(TOC)is correlated positively with many trace elements.In the outer shelf,slope,and adjacent areas,hydrothermal activity and upwelling current bring nutrient-rich material and promote organic matter enrichment under a strong reducing condition.Deep-shelf,slope and deep-water basin are the best facies for the formation and preservation of organic matter,especially deep-water basin facies.It remains necessary to strengthen the exploration of shale gas in the deep-water basin of∈1n in central Hunan,China.展开更多
Due to the growing need for sustainable and ultra-high-strength construction materials,scientists have created an innovative ultra-high-performance concrete called Geopolymer based ultra-highperformance concrete(GUHPC...Due to the growing need for sustainable and ultra-high-strength construction materials,scientists have created an innovative ultra-high-performance concrete called Geopolymer based ultra-highperformance concrete(GUHPC).Besides,in the last few decades,there have been a lot of explosions and ballistic attacks around the world,which have killed many civilians and fighters in border areas.In this context,this article reviews the fresh state and mechanical properties of GUHPC.Firstly,the ingredients of GUHPC and fresh properties such as setting time and flowability are briefly covered.Secondly,the review of compressive strength,flexure strength,tensile strength and modulus of elasticity of fibrous GUHPC.Thirdly,the blast and projectile impact resistance performance was reviewed.Finally,the microstructural characteristics were reviewed using the scanning electron microscope and X-ray Powder Diffraction.The review outcome reveals that the mechanical properties were increased when 30%silica fume was added to a higher dose of steel fibre to improve the microstructure of GUHPC.It is hypothesized that the brittleness of GUHPC was mitigated by adding 1.5%steel fibre reinforcement,which played a role in the decrease of contact explosion cratering and spalling.Removing the need for cement in GUHPC was a key factor in the review,indicating a promising potential for lowering carbon emissions.However,GUHPC research is still in its early stages,so more study is required before its full potential can be utilized.展开更多
Background&Objective Knee osteoarthritis(OA)is a degenerative disease,which not only induces superficial cartilage defects and full-thickness cartilage defects,but also exacerbates the microenvironment of the knee...Background&Objective Knee osteoarthritis(OA)is a degenerative disease,which not only induces superficial cartilage defects and full-thickness cartilage defects,but also exacerbates the microenvironment of the knee joint and affects the mechano-chemical responses of the organ.As a growth/repair factor,mechanical growth factor(MGF)has the function of preventing OA,promoting cartilage regeneration and repairing damaged ligaments.activating transcription factor 2(ATF-2),a transcription factor,has the property of binding to cytokines,which makes it involved in the transcriptional regulation of various pathways in response to cellular stress,inflammatory cytokine and growth factors.At present,little is known about the effect of MGF on human osteoarthritis ligament fibroblasts(OA-LFs),and whether the approach can promote OA-LFs timely response to the mechanical injury and initiate signaling pathway for cell survival.Therefore,the purpose of this study is to investigate whether MGF promotes mechanical response to ligament fibroblasts in osteoarthritis knee cavity via ATF-2.Methods OA-LFs were seeded onto six-cell BioFlex plates and suffered from 12%static mechanical stretch[60 cycles/minute(1 Hz)]for 12 hours to mimic mechanical force mediated ligament injury.Meanwhile,OA-LFs were treated with MGF before and during mechanical stretch.Intracellular reactive oxygen species(ROS)and GRP78 mRNA expression were investigated to detect the cellular stress response of OA-LFs.The scratch test was performed to detect the migration ability of cells,gelatin zymography was used to examine the effect of MGF on the activity of matrix metalloproteinase 2(MMP-2)in OA-LFs,and cell deformation was detected by phalloidin-FITC staining after stretching.Quantitative real-time polymerase chain reaction(qRT-PCR)was used to screen the messenger RNA(mRNA)expression of ATF family members after OALFs treatment with MGF.Western blotting further proved that MGF is capable to activate the p-ATF-2.Results OA delays LFs response to mechanical injury,while MGF pretreatment can promote cells timely feedback the mechanically stimuli by inducing cellular stress.MGF treatment can alleviate the decline in cell migration ability caused by mechanical injury and further promote cell migration.In addition,MGF can reduce the activity of MM P-5 and alleviate the stretch-induced deformation of OA-LFs.Furthermore,the mRNA expression of ATF-2 up-regulated in a dose-dependent manner upon MGF treatment compared with control,while the expression of ATF-5 gene was down-regulated in a dose-dependent.Protein levels showed that the expression of p-ATF-2 increased with increasing MGF concentration.Conclusions Our study shows that MGF pretreatment of OA-LFs can respond quickly to mechanical damage and accelerate the ligament injury repair by promoting cell migration,decreasing the MMP-2 activity,and remitting the cell deformation.Therefore,MGF has potential as a therapeutic for OA patients.展开更多
BK channels are widely expressed in both excitable and non-excitable cells and known to be involved in many physiological processes,such as vascular smooth tone regulation,neuronal firing and endocrine cell secretion[...BK channels are widely expressed in both excitable and non-excitable cells and known to be involved in many physiological processes,such as vascular smooth tone regulation,neuronal firing and endocrine cell secretion[1].Recently, the BK channels have展开更多
为明确L-香芹酮的熏蒸抑菌活性和其作用机制,本研究利用菌丝生长速率法测定了L-香芹酮对灰葡萄孢、核盘菌、齐整小核菌、禾谷镰孢、胶孢炭疽菌5种植物病原菌的熏蒸抑制作用,采用孢子萌发法进一步探究了L-香芹酮对灰葡萄孢的作用,通过扫...为明确L-香芹酮的熏蒸抑菌活性和其作用机制,本研究利用菌丝生长速率法测定了L-香芹酮对灰葡萄孢、核盘菌、齐整小核菌、禾谷镰孢、胶孢炭疽菌5种植物病原菌的熏蒸抑制作用,采用孢子萌发法进一步探究了L-香芹酮对灰葡萄孢的作用,通过扫描电镜和透射电镜观察熏蒸处理后灰葡萄孢菌丝微观形态和亚细胞结构的变化,利用PI染色观察细胞膜的损伤情况,并测定L-香芹酮对灰葡萄孢麦角甾醇合成、细胞膜胞外电导率、蛋白质和核酸含量的影响,开展了L-香芹酮对草莓灰霉病的离体防效试验。结果显示,L-香芹酮对5种植物病原菌菌丝生长有明显的抑制作用,熏蒸72 h EC_(50)在5.29~18.69μL/L之间。对灰葡萄孢孢子萌发的EC_(50)为11.78μL/L;经L-香芹酮熏蒸处理后灰葡萄孢菌丝干瘪,扭曲,细胞器结构紊乱;PI染色结果表明,L-香芹酮熏蒸处理严重影响灰葡萄孢细胞膜的完整性,EC_(50)和EC_(90)剂量处理组麦角甾醇含量分别降低27.3%和43.2%,胞内物质外泄,菌丝液的相对电导率上升,蛋白质和核酸类物质外渗程度高于对照。EC_(90)剂量熏蒸处理对草莓灰霉病治疗和保护防控效果分别为85.43%和90.31%。综上,L-香芹酮可通过破坏灰葡萄孢细胞膜的完整性和通透性来发挥抑菌功效,对草莓灰霉病有较好的防治效果,该结果为新型植物源熏蒸杀菌剂的开发提供了新思路。展开更多
基金Project(5227010679)supported by the National Natural Science Foundation of China。
文摘The process of preparing anodic oxide film containing active sites and electroless nickel plating on highly active rare earth magnesium alloy was developed.The formation mechanism of electroless nickel plating on active anodic oxide film and the structure and properties of the composite coating were studied by several surface and electrochemical techniques.The results showed that Ag nanograins with an average size of 10 nm were embedded into the anodic oxide film with pores of 0.1−2μm.Ag nanoparticles provided a catalytic site for the deposition of Ni-B alloy,and the Ni crystal nucleus was first grown in horizontal mode and then in cylindrical mode.The corrosion potential of the composite coating increased by 1.37 V and the corrosion current reduced two orders of magnitude due to the subsequent deposition of Ni-P alloy.The high corrosion resistance was attributed to the misaligning of these micro defects in the three different layers and the amorphous structure of the Ni-P alloy in the outer layer.These findings provide a new idea for electroless nickel plating on anodic oxide film.
文摘The antidepressive effect of Xiaoyaosan is doubtless by researches while the potential antidepressive ac- tive ingredients and their mechanisms remain unclear. In order to explain the antidepressive effect of Xiaoyaosan, all of the recent reports were sought out on the current situation of the antidepressive monomer compositions of Xi- aoyaosan and their mechanism. By exploring the relationship between the effects and the active ingredients, the mechanism and the active ingredients, the antidepressive active ingredients such as quercetin, isorhamnetin, isoliquiritigenin, saikosaponinA, saikosaponinD, glycyrrhiz- kaempferol, liquiritin, isoliquiritin, liquiritigenin, inate, paeoniflorin, albiflorin, ferulic acid, curcumin and their mechanism of antidepressive such as regulating the monoamine neurotransmitter systems, regulating the neuroendocrine system, affecting the neural plasticity and neu- affecting the cytokines level, anti-oxidative stress were rotrophic, affecting the cellular and molecular mechanisms , summarized. By the overview in the level of monomer rather than formulae, we uncovered the antidepressive mech- anism of Xiaoyaosan and further confirmed that Xiaoyaosan, as a classic antidepressive Chinese prescription, had many characteristics, such as multi-level , multi-channel, multi-target and so on .
文摘Based on physicochemical study of the reaction between scheelite and NaOH, a new decomposition process for scheelite and scheelitewolframite concentrate, i. e., mechenically activating caustic decomposition has been developed, and it has been successfu
文摘The micromation and precision of the Micro-Electromechanical System demand that its manufacturing, measuring and assembling must work in a micro-manufacturing platform with good ability to isolate vibrations. This paper develops a vibration isolation system of micro-manufacturing platform. The brains of many kinds of birds can isolate vibrations well, such as woodpecker’s brain. When a woodpecker pecks the wood at the speed as 1.6 times as the velocity of sound, its brain will tolerate the wallop 1 500 times of the weight of itself without any damage. The isolation mechanics and organic texture of woodpecker’s brain that has good isolation characteristics were studied. A structure model of vibration isolation system for the micro-manufacturing platform is established based on the bionics of the bird’s brain vibration isolation mechanism. In order to isolate effectively the high frequency vibrations from the ground, a rubber layer is used to isolate vibrations passively between the micro-manufacturing platform’s pedestal and the ground. This layer corresponds to the cartilage and muscles in the outer meninges of the bird’s brain. The active vibration isolation technique is adopted to isolate vibrations between the micro-manufacturing platform and the pedestal. Air springs are used as elastic components, which correspond to the interspaces between the outer meninges and the encephala of the bird’s brain. Actuators are made of giant magnetostrictive material, and it corresponds to the nerves and neural muscles linking the meninges and the encephala. The actuators and air springs are arranged vertically in parallel to make use of the giant magnetostrictive actuators effectively. The air springs support almost all weight of the micro-manufacturing platform and the giant magnetostrictive actuators support almost no weight. In order to realize high performance to isolate complex micro-vibration, the control method using a three-layer neural network is presented. This vibration control system takes into account the floor disturbance and the direct disturbance acting on the micro-manufacturing platform. The absolute acceleration of the micro-manufacturing platform is used as the performance index of vibration control. The performance of the control system is tested by numerical simulation. Simulation results show that the active vibration isolation system has good isolation performance against the floor disturbance and the direct disturbance acting on the micro-manufacturing platform in all the frequency range.
基金Project(2020YFC1908802) supported by the National Key Research and Development Project of China。
文摘Natural minerals receive growing attention as inexpensive, green, and efficient catalysts for degradation of organic pollutants. Mechanical activation of natural chalcopyrite was conducted for improving the catalytic performance.Tetracycline degradation was evaluated in the presence of hydrogen peroxide and mechanically activated chalcopyrite.Tetracycline degradation at 100 min is 55.52%(Chp10), 68.97%(Chp30), 77.79%(Chp60), and 86.43%(Chp120),respectively, and the rate constant of pseudo-first-order kinetics is 0.0079, 0.0109, 0.0137 and 0.0192 min^(-1), respectively.Chalcopyrite samples were examined by multiple characterizations. Mechanical activation of natural chalcopyrite induces the decline of particle size and slight increase of surface area, smaller grain size, lattice strain, and partial sulfur oxidation. The relationship between catalytic activity and property change manifests that the improved catalytic ability is mainly ascribed to the increase of surface area and surface oxidation induced by mechanical activation. This work provides novel insights into the improvement of catalytic performance of natural minerals by mechanical activation.
基金the Key+7 种基金 Programof the 8th Five-year Plan of China
文摘Leaching of lowgrade refractory tungsten ore was carried out through mechanical activation. The effect of temperature, amount of Na2CO3, addition of NaOH, ratio of liquid to solid and leaching time on the recovery of WO3 was studied. The WO3 recovery upto 96%～99% has been achieved when the tungsten ore was digested by soda not more than three times stiochiometric amount at 185～195 ℃ for 10～20 h. The WO3 recovery can increase 10%～15% compared to that of conventional soda autoclave process.
基金Project(2017GK2233)supported by the Science and Technology Innovation Program of Hunan Provine,ChinaProject(2017JJ1034)supported by the Natural Science Foundation of Hunan Province,China。
文摘The purpose of this study was to examine the sedimentary facies characteristics of lower Cambrian Niutitang Formation(∈1n)in South China,to reveal the mechanism of organic matter enrichment,and to guide exploration of shale gas.Macro investigation and experimental analyses were used to assess the lithology in detail,total organic matter mass fraction w(TOC),mineral composition,and trace element characteristics of∈1n.The influencing factors of organic matter enrichment were discussed extensively,and a sedimentary facies mode was suggested.In the early stage of∈1n,the locations of Well E’yangye 1,Well Ciye 1,Well Changye 1,and Well Anye 1 respectively develop,platform inner sag,outer shelf,Jiangnan slope belt,and South China detention basin.In the late stage of∈1n,the sedimentary facies evolve with decreasing sea level.The study area presents a complete three-step basin in the Early Cambrian.In the early stage of∈1n,the first step is the Yangtze carbonate platform,the second step is the outer shelf and slope,and the third step is the deep-water basin.From the Yangtze carbonate platform to the deep-water basin,w(TOC)and the mass fraction of quartz gradually increase,the mass fraction of carbonate mineral decreases,and the mass fraction of clay mineral is higher in the second step.The sea level fluctuation results in a higher w(TOC)vertically in the lower∈1n shale,and the paleogeographic(provenance)conditions lead to better horizontal development of organic matter in the outer shelf,slope and detention basin.Trace elements are abundant in the lower∈1n,and w(TOC)is correlated positively with many trace elements.In the outer shelf,slope,and adjacent areas,hydrothermal activity and upwelling current bring nutrient-rich material and promote organic matter enrichment under a strong reducing condition.Deep-shelf,slope and deep-water basin are the best facies for the formation and preservation of organic matter,especially deep-water basin facies.It remains necessary to strengthen the exploration of shale gas in the deep-water basin of∈1n in central Hunan,China.
文摘Due to the growing need for sustainable and ultra-high-strength construction materials,scientists have created an innovative ultra-high-performance concrete called Geopolymer based ultra-highperformance concrete(GUHPC).Besides,in the last few decades,there have been a lot of explosions and ballistic attacks around the world,which have killed many civilians and fighters in border areas.In this context,this article reviews the fresh state and mechanical properties of GUHPC.Firstly,the ingredients of GUHPC and fresh properties such as setting time and flowability are briefly covered.Secondly,the review of compressive strength,flexure strength,tensile strength and modulus of elasticity of fibrous GUHPC.Thirdly,the blast and projectile impact resistance performance was reviewed.Finally,the microstructural characteristics were reviewed using the scanning electron microscope and X-ray Powder Diffraction.The review outcome reveals that the mechanical properties were increased when 30%silica fume was added to a higher dose of steel fibre to improve the microstructure of GUHPC.It is hypothesized that the brittleness of GUHPC was mitigated by adding 1.5%steel fibre reinforcement,which played a role in the decrease of contact explosion cratering and spalling.Removing the need for cement in GUHPC was a key factor in the review,indicating a promising potential for lowering carbon emissions.However,GUHPC research is still in its early stages,so more study is required before its full potential can be utilized.
基金supported by the National Natural Science Foundation of China ( 11532004,31270990, 31600762)Innovation and Attracting Talents Program for College and University( “111”Project) ( B06023)
文摘Background&Objective Knee osteoarthritis(OA)is a degenerative disease,which not only induces superficial cartilage defects and full-thickness cartilage defects,but also exacerbates the microenvironment of the knee joint and affects the mechano-chemical responses of the organ.As a growth/repair factor,mechanical growth factor(MGF)has the function of preventing OA,promoting cartilage regeneration and repairing damaged ligaments.activating transcription factor 2(ATF-2),a transcription factor,has the property of binding to cytokines,which makes it involved in the transcriptional regulation of various pathways in response to cellular stress,inflammatory cytokine and growth factors.At present,little is known about the effect of MGF on human osteoarthritis ligament fibroblasts(OA-LFs),and whether the approach can promote OA-LFs timely response to the mechanical injury and initiate signaling pathway for cell survival.Therefore,the purpose of this study is to investigate whether MGF promotes mechanical response to ligament fibroblasts in osteoarthritis knee cavity via ATF-2.Methods OA-LFs were seeded onto six-cell BioFlex plates and suffered from 12%static mechanical stretch[60 cycles/minute(1 Hz)]for 12 hours to mimic mechanical force mediated ligament injury.Meanwhile,OA-LFs were treated with MGF before and during mechanical stretch.Intracellular reactive oxygen species(ROS)and GRP78 mRNA expression were investigated to detect the cellular stress response of OA-LFs.The scratch test was performed to detect the migration ability of cells,gelatin zymography was used to examine the effect of MGF on the activity of matrix metalloproteinase 2(MMP-2)in OA-LFs,and cell deformation was detected by phalloidin-FITC staining after stretching.Quantitative real-time polymerase chain reaction(qRT-PCR)was used to screen the messenger RNA(mRNA)expression of ATF family members after OALFs treatment with MGF.Western blotting further proved that MGF is capable to activate the p-ATF-2.Results OA delays LFs response to mechanical injury,while MGF pretreatment can promote cells timely feedback the mechanically stimuli by inducing cellular stress.MGF treatment can alleviate the decline in cell migration ability caused by mechanical injury and further promote cell migration.In addition,MGF can reduce the activity of MM P-5 and alleviate the stretch-induced deformation of OA-LFs.Furthermore,the mRNA expression of ATF-2 up-regulated in a dose-dependent manner upon MGF treatment compared with control,while the expression of ATF-5 gene was down-regulated in a dose-dependent.Protein levels showed that the expression of p-ATF-2 increased with increasing MGF concentration.Conclusions Our study shows that MGF pretreatment of OA-LFs can respond quickly to mechanical damage and accelerate the ligament injury repair by promoting cell migration,decreasing the MMP-2 activity,and remitting the cell deformation.Therefore,MGF has potential as a therapeutic for OA patients.
基金supported by Natural Science Foundation of China grants10732070,10602031
文摘BK channels are widely expressed in both excitable and non-excitable cells and known to be involved in many physiological processes,such as vascular smooth tone regulation,neuronal firing and endocrine cell secretion[1].Recently, the BK channels have
文摘为明确L-香芹酮的熏蒸抑菌活性和其作用机制,本研究利用菌丝生长速率法测定了L-香芹酮对灰葡萄孢、核盘菌、齐整小核菌、禾谷镰孢、胶孢炭疽菌5种植物病原菌的熏蒸抑制作用,采用孢子萌发法进一步探究了L-香芹酮对灰葡萄孢的作用,通过扫描电镜和透射电镜观察熏蒸处理后灰葡萄孢菌丝微观形态和亚细胞结构的变化,利用PI染色观察细胞膜的损伤情况,并测定L-香芹酮对灰葡萄孢麦角甾醇合成、细胞膜胞外电导率、蛋白质和核酸含量的影响,开展了L-香芹酮对草莓灰霉病的离体防效试验。结果显示,L-香芹酮对5种植物病原菌菌丝生长有明显的抑制作用,熏蒸72 h EC_(50)在5.29~18.69μL/L之间。对灰葡萄孢孢子萌发的EC_(50)为11.78μL/L;经L-香芹酮熏蒸处理后灰葡萄孢菌丝干瘪,扭曲,细胞器结构紊乱;PI染色结果表明,L-香芹酮熏蒸处理严重影响灰葡萄孢细胞膜的完整性,EC_(50)和EC_(90)剂量处理组麦角甾醇含量分别降低27.3%和43.2%,胞内物质外泄,菌丝液的相对电导率上升,蛋白质和核酸类物质外渗程度高于对照。EC_(90)剂量熏蒸处理对草莓灰霉病治疗和保护防控效果分别为85.43%和90.31%。综上,L-香芹酮可通过破坏灰葡萄孢细胞膜的完整性和通透性来发挥抑菌功效,对草莓灰霉病有较好的防治效果,该结果为新型植物源熏蒸杀菌剂的开发提供了新思路。
