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Modeling time-dependent mechanical behavior of hard rock considering excavation-induced damage and complex 3D stress states 被引量:1
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作者 Peiyang Yu Xiuli Ding +3 位作者 Peng-Zhi Pan Shuting Miao Zhaofeng Wang Shuling Huang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第10期4046-4065,共20页
To investigate the long-term stability of deep rocks,a three-dimensional(3D)time-dependent model that accounts for excavation-induced damage and complex stress state is developed.This model comprises three main compon... To investigate the long-term stability of deep rocks,a three-dimensional(3D)time-dependent model that accounts for excavation-induced damage and complex stress state is developed.This model comprises three main components:a 3D viscoplastic isotropic constitutive relation that considers excavation damage and complex stress state,a quantitative relationship between critical irreversible deformation and complex stress state,and evolution characteristics of strength parameters.The proposed model is implemented in a self-developed numerical code,i.e.CASRock.The reliability of the model is validated through experiments.It is indicated that the time-dependent fracturing potential index(xTFPI)at a given time during the attenuation creep stage shows a negative correlation with the extent of excavationinduced damage.The time-dependent fracturing process of rock demonstrates a distinct interval effect of the intermediate principal stress,thereby highlighting the 3D stress-dependent characteristic of the model.Finally,the influence of excavation-induced damage and intermediate principal stress on the time-dependent fracturing characteristics of the surrounding rocks around the tunnel is discussed. 展开更多
关键词 Hard rock Excavation damage Complex stress state Three-dimensional(3D)time-dependent model
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Critical current degradation in an epoxy-impregnated rare-earth Ba_(2)Cu_(3)O_(7-x)coated conductor caused by damage during a quench
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作者 Donghui LIU Huadong YONG Youhe ZHOU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第9期1557-1572,共16页
High-temperature superconducting(HTS)rare-earth Ba_(2)Cu_(3)O_(7-x)(REBCO)coated conductors(CCs)have significant potential in high-current and high-field applications.However,owing to the weak interface strength of th... High-temperature superconducting(HTS)rare-earth Ba_(2)Cu_(3)O_(7-x)(REBCO)coated conductors(CCs)have significant potential in high-current and high-field applications.However,owing to the weak interface strength of the laminated composite REBCO CCs,the damage induced by the thermal mismatch stress under a combination of epoxy impregnation,cooling,and quenching can cause premature degradation of the critical current.In this study,a three-dimensional(3D)electromagnetic-thermal-mechanical model based on the H-formulation and cohesive zone model(CZM)is developed to study the critical current degradation characteristics in an epoxy-impregnated REBCO CC caused by the damage during a quench.The temperature variation,critical current degradation of the REBCO CC,and its degradation onset temperature calculated by the numerical model are in agreement with the experimental data taken from the literature.The delamination of the REBCO CC predicted by the numerical model is consistent with the experimental result.The numerical results also indicate that the shear stress is the main contributor to the damage propagation inside the REBCO CC.The premature degradation of the critical current during a quench is closely related to the interface shear strength inside the REBCO CC.Finally,the effects of the coefficient of thermal expansion(CTE)of the epoxy resin,thickness of the substrate,and substrate material on the critical current degradation characteristics of the epoxy-impregnated REBCO CC during a quench are also discussed.These results help us understand the relationship between the current-carrying degradation and damage in the HTS applications. 展开更多
关键词 epoxy-impregnated rare-earth Ba_(2)Cu_(3)O_(7-x)(REBCO)coated conductor(CC) QUENCH damage critical current degradation shear stress
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Three-dimensional Building Damage Simulation Based on GIS
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作者 Gu Guoliang Jiang Lixin 《Earthquake Research in China》 2012年第4期520-531,共12页
GIS technology has been applied to building damage analysis around the world. However, most previous studies focused on the application of 2-D GIS technology, and the results from traditional earthquake damage predict... GIS technology has been applied to building damage analysis around the world. However, most previous studies focused on the application of 2-D GIS technology, and the results from traditional earthquake damage prediction are displayed in 2-D figures and charts, which is incapable of demonstrating the 3-D spatial characteristics of buildings. Taking brick-concrete building as an example, we study the characteristics of building damage, and effectively combine the information of building textures and earthquake damage. Then, we apply Google SketchUp techniques to create building models and display them with seismic damage texture in the ArcGIS Engine software development environment. In this paper we propose a solid idea for 3-D simulation of earthquake damage, which is helpful in earthquake damage prediction, virtual emergency rescue practice and earthquake knowledge education. 展开更多
关键词 Google SketchUp 3-D GIS Earthquake damage prediction Earthquake damage simulation
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A methodology for damage evaluation of underground tunnels subjected to static loading using numerical modeling 被引量:1
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作者 Shahriyar Heidarzadeh Ali Saeidi 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第6期1993-2005,共13页
We have proposed a methodology to assess the robustness of underground tunnels against potential failure.This involves developing vulnerability functions for various qualities of rock mass and static loading intensiti... We have proposed a methodology to assess the robustness of underground tunnels against potential failure.This involves developing vulnerability functions for various qualities of rock mass and static loading intensities.To account for these variations,we utilized a Monte Carlo Simulation(MCS)technique coupled with the finite difference code FLAC^(3D),to conduct two thousand seven hundred numerical simulations of a horseshoe tunnel located within a rock mass with different geological strength index system(GSIs)and subjected to different states of static loading.To quantify the severity of damage within the rock mass,we selected one stress-based(brittle shear ratio(BSR))and one strain-based failure criterion(plastic damage index(PDI)).Based on these criteria,we then developed fragility curves.Additionally,we used mathematical approximation techniques to produce vulnerability functions that relate the probabilities of various damage states to loading intensities for different quality classes of blocky rock mass.The results indicated that the fragility curves we obtained could accurately depict the evolution of the inner and outer shell damage around the tunnel.Therefore,we have provided engineers with a tool that can predict levels of damages associated with different failure mechanisms based on variations in rock mass quality and in situ stress state.Our method is a numerically developed,multi-variate approach that can aid engineers in making informed decisions about the robustness of underground tunnels. 展开更多
关键词 Fragility curves Underground tunnels Vulnerability functions Brittle damage FLAC3D Numerical modeling
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Damage evolution of rock-encased-backfill structure under stepwise cyclic triaxial loading 被引量:1
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作者 Xin Yu Yuye Tan +4 位作者 Weidong Song John Kemeny Shengwen Qi Bowen Zheng Songfeng Guo 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第2期597-615,共19页
Rock-encased-backfill(RB)structures are common in underground mining,for example in the cut-andfill and stoping methods.To understand the effects of cyclic excavation and blasting activities on the damage of these RB ... Rock-encased-backfill(RB)structures are common in underground mining,for example in the cut-andfill and stoping methods.To understand the effects of cyclic excavation and blasting activities on the damage of these RB structures,a series of triaxial stepwise-increasing-amplitude cyclic loading experiments was conducted with cylindrical RB specimens(rock on outside,backfill on inside)with different volume fractions of rock(VF=0.48,0.61,0.73,and 0.84),confining pressures(0,6,9,and 12 MPa),and cyclic loading rates(200,300,400,and 500 N/s).The damage evolution and meso-crack formation during the cyclic tests were analyzed with results from stress-strain hysteresis loops,acoustic emission events,and post-failure X-ray 3D fracture morphology.The results showed significant differences between cyclic and monotonic loadings of RB specimens,particularly with regard to the generation of shear microcracks,the development of stress memory and strain hardening,and the contact forces and associated friction that develops along the rock-backfill interface.One important finding is that as a function of the number of cycles,the elastic strain increases linearly and the dissipated energy increases exponentially.Also,compared with monotonic loading,the cyclic strain hardening characteristics are more sensitive to rising confining pressures during the initial compaction stage.Another finding is that compared with monotonic loading,more shear microcracks are generated during every reloading stage,but these microcracks tend to be dispersed and lessen the likelihood of large shear fracture formation.The transition from elastic to plastic behavior varies depending on the parameters of each test(confinement,volume fraction,and cyclic rate),and an interesting finding was that the transformation to plastic behavior is significantly lower under the conditions of 0.73 rock volume fraction,400 N/s cyclic loading rate,and 9 MPa confinement.All the findings have important practical implications on the ability of backfill to support underground excavations. 展开更多
关键词 Rock and backfill Triaxial cyclic loading Volume fraction damage evolution 3D visualization
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ROLE OF CASPASE-3 IN ACUTE LIGHT DAMAGE TO RETINA OF RATS 被引量:5
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作者 Xiao Wang Shi-xing Hu +1 位作者 Wei Li Shao-chun Lin 《Chinese Medical Sciences Journal》 CAS CSCD 2007年第1期44-48,共5页
Objective To investigate the role of Caspase-3 in retinal damage caused by hght exposure in rats. Methods Light injury to retina was induced by persistent exposure to illumination (intensity : 30 000 ± 50 lux... Objective To investigate the role of Caspase-3 in retinal damage caused by hght exposure in rats. Methods Light injury to retina was induced by persistent exposure to illumination (intensity : 30 000 ± 50 lux) of operating microscope for 30 minutes in the right eyes of Sprague-Dawley rats. The pathological changes of retina were observed under optical and electron microscopies at different time points, which were 6 hours, 1,3,7, and 15 days after the hght exposure. Apoptosis of retinal cells was analyzed by flow cytometry. The activity of Caspase-3 was evaluated by using the Caspase-3 assay kit. At the same time, the expression of Caspase-3 protease was determined with Western blot analysis. Results The examination results of optical and transmission electron microscopes showed that edema of inner and outer segments of the retina, especially the chondriosome inside the inner segment, became obvious 6 hours after the light exposure. The change was deteriorated along with the increasing time. The structures of the discoidal valve dissociated in the outer segment simultaneously. Disorderly arranged nuclei, karyopycnosis, and thinning in the outer nuclear layer were observed. The retinal pigment epithelium almost disappeared during the later stage. The staining results of Annexin-V combined with PI demonstrated that the proportion of apoptotic cells increased with time. The proportion between 7th day (82.7%) and 15th day (80.4%), however, showed no significant difference. Caspase-3 became remarkably active with the lapse of time, which increased from 0.02 at 6th hour to the peak of 9. 8 at 7th day before it started to descend. The Western blot detected a expression of the active form of Caspase-3 at 7th day and 15th day. Conclusion Apoptosis of photoreceptor cells is markedly involved in the light damage and Caspase-3 protease may play an important role in the apoptotic process of the retina after light exposure in rats. 展开更多
关键词 RETINA light damage CASPASE-3 APOPTOSIS RAT
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Tribulus terrestris extracts alleviate muscle damage and promote anaerobic performance of trained male boxers and its mechanisms: Roles of androgen, IGF-1, and IGF binding protein-3 被引量:2
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作者 Yiming Ma Zhicheng Guo Xiaohui Wang 《Journal of Sport and Health Science》 SCIE 2017年第4期474-481,共8页
Purpose: To investigate the effects of Tribulus terrestris(TT) extracts on muscle mass, muscle damage, and anaerobic performances of trained male boxers and its mechanisms: roles of plasma androgen, insulin growth fac... Purpose: To investigate the effects of Tribulus terrestris(TT) extracts on muscle mass, muscle damage, and anaerobic performances of trained male boxers and its mechanisms: roles of plasma androgen, insulin growth factor 1(IGF-1), and IGF-1 binding protein-3(IGFBP-3).Methods: Fifteen male boxers were divided into exercise group(E, n = 7) and exercise plus TT group(E + TT, n = 8). The 2 groups both undertook3-week high-intensity and 3-week high-volume trainings separated by a 4-week rest. TT extracts(1250 mg/day) were orally administered by boxers in E + TT group. TT extract compositions were detected by UHPLC–Q-TOF/MS. Before and at the end of the 2 trainings, muscle mass, anaerobic performance, and blood indicators were explored.Results: Compared with E group, decreases of plasma CK(1591.5 ± 909.6 U/L vs. 2719.9 ± 832.5 U/L) and IGFBP-3(3075.5 ± 1072.5 ng/m L vs. 3950.8 ± 479.3 ng/m L) as well as increases of mean power(MP, 459.4 ± 122.3 W vs. 434.6 ± 69.5 W) and MP/body weight(MP/BW, 7.5 ± 0.9 W/kg vs. 7.1 ± 1.1 W/kg) were detected in E + TT group after a high-intensity training. For high-volume training, reduction of IGFBP-3(2946.4 ± 974.1 ng/m L vs. 3632.7 ± 470.1 ng/m L) and increases of MP(508.7 ± 103.2 W vs. 477.8 ± 49.9 W) and MP/BW(8.2 ± 0.3 W/kg vs.7.5 ± 0.9 W/kg) were detected in E + TT group, compared with E group. Muscle mass, blood levels of testosterone, dihydrotestosterone(DHT),and IGF-1 were not signifiantly changed between the 2 groups.Conclusion: Taking 1250 mg capsules containing TT extracts did not change muscle mass and plasma levels of testosterone, DHT, and IGF-1 but significantly alleviated muscle damage and promoted anaerobic performance of trained male boxers, which may be related to the decrease of plasma IGFBP-3 rather than androgen in plasma. 展开更多
关键词 IGF binding protein-3 Insulin growth factor 1(IGF-1) Muscle damage PERFORMANCE Testosterone Tribulus terrestris
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3D Measurement and Stereo Reconstruction for Aeroengine Interior Damage 被引量:5
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作者 陈果 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2004年第3期149-151,共3页
The borescopy inspection problem of aeroengine interior important partdamages such as firebox's burn and corruption, vane' s crack, bump, abrade and concave pit, is aimedat. A new system is developed to carry ... The borescopy inspection problem of aeroengine interior important partdamages such as firebox's burn and corruption, vane' s crack, bump, abrade and concave pit, is aimedat. A new system is developed to carry out 3D measurement and stereo reconstruction of engineinterior damage, in which the borescope of Japanese OLYMPUS Corporation is used as hardware. In thesystem, functions are implemented, such as image collection, camera calibration, imagepreprocessing, stereo matching, 3D measurement and stereo reconstruction. It can provide moredetailed inspection and more accurate estimation of engine interior damages. Finally, an example isused to verify the effectivity of the new method. 展开更多
关键词 AEROENGINE nondestructive testing (NDT) interior damage inspection 3Dmeasurement stereo reconstruction
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Inhibiting PI3K/Akt Pathway Increases DNA Damage of Cervical Carcinoma HeLa Cells by Drug Radiosensitization 被引量:4
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作者 夏曙 于世英 +4 位作者 付强 刘飞 郑微 付秀根 赵茵 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2010年第3期360-364,共5页
This study examined the role of PI3K/Akt pathway in radiosensitization of DNA damage of cervical carcinoma cells.The 50% inhibition concentration(IC50) of cisplatin and docetaxel in HeLa cells was detected by Mono-nuc... This study examined the role of PI3K/Akt pathway in radiosensitization of DNA damage of cervical carcinoma cells.The 50% inhibition concentration(IC50) of cisplatin and docetaxel in HeLa cells was detected by Mono-nuclear cell direct cytotoxicity assay(MTT) in vitro.HeLa cells were treated by cisplatin/docetaxel of 10 percent of IC20 alone or combined with LY294002 for 24 h,and then radiated by different doses of X-ray.The cell survival ratio was obtained by means of clone formation.One-hit multi-target model was fitted to the cell survival curve to calculate dose quasithreshold(Dq),mean lethal dose(D0),2Gy survival fraction(SF2) and sensitization enhancement ratio(SER).The pAkt and total Akt expression was detected by Western blotting and DNA damage by neutro-comet electrophoresis.The HeLa cells were randomly divided into 7 groups in terms of different treatments:Control;radiation treatment(RT) group;LY294002+RT group;cisplatin+RT group;docetaxel+RT group;LY294002+cisplatin+RT group;LY294002+docetaxel+RT group.The apoptosis ratio of each group was measured by flow cytometry.The results showed that docetaxel and cisplatin significantly enhanced the phosphorylation of Akt in radiation-treated HeLa cells.The Dq,D0 and SF2 in LY294002-contained groups were lower than those in docetaxel or cisplatin+RT group.The SER in the LY294002+docetaxel+RT group was 1.35 times that of the docetaxel+RT group,and that in the LY294002+cisplatin+RT group 1.26 times that of the cisplatin+RT group.The Comet electrophoresis showed that tail distance in the LY294002+cisplatin+RT group or LY294002+docetaxel+RT group was longer than in the cisplatin+RT group or docetaxel+RT group.The apoptosis ratio in the LY294002+cisplatin+RT group or LY294002+docetaxel +RT group was higher than in the cisplatin+RT group or docetaxel+RT group.It was concluded that inhibiting PI3K/Akt pathway can increase the effect of docetaxel and cisplatin on the radiosensitivity of HeLa cells and DNA damage resulted from radiation. 展开更多
关键词 cervical carcinoma PI3K/Akt pathway RADIOSENSITIZATION LY294002 DOCETAXEL CISPLATIN DNA damage
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20(R)-ginsenoside Rg3,a product of high-efficiency thermal deglycosylation of ginsenoside Rd,exerts protective effects against scrotal heat-induced spermatogenic damage in mice 被引量:3
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作者 WEI LIU ZI WANG +7 位作者 JING LENG HENG WEI SHEN REN XIAOJIE GONG CHEN CHEN YINGPING WANG RUI ZHANG WEI LI 《BIOCELL》 SCIE 2020年第4期655-669,共15页
Heat stress(HS)reaction can lead to serious physiological dysfunction associated with cardiovascular and various organ diseases.Ginsenoside Rg3(G-Rg3)is a representative component of ginseng rare saponin and can prote... Heat stress(HS)reaction can lead to serious physiological dysfunction associated with cardiovascular and various organ diseases.Ginsenoside Rg3(G-Rg3)is a representative component of ginseng rare saponin and can protect against multiple organs,also used as functional food to adjust the balance of the human body,but the therapeutic effect and molecular mechanism of G-Rg3 on male diseases under HS are underexplored.The aim of the present study,G-Rg3 was prepared through the efficient conversion of ginsenoside Rd and investigate the contribution of G-Rg3 to testicular injury induced exposure to HS.All mice were divided into four groups as follows:normal group,HS group,and HS+G-Rg3(5 and 10 mg/kg)groups.G-Rg3 was administered orally for 14 days,then exposed to a single scrotal heat treatment(43°C,18min)on the 7th day.After HS treatment,the morphology of testis and epididymis changes,and caused a significant loss of multinucleated giant cells,desquamation of germ cells in destructive seminiferous tubules,and degenerative Leydig cells,further destroying the production of sperm.After administration G-Rg3(5 and 10 mg/kg/day)for 2 weeks,the spermatogenic-related indexes of testosterone levels and superoxide dismutase(SOD)activity,glutathione(GSH)content significantly(p<0.01)increase compared with the HS group.Moreover,G-Rg3 treatment effectively ameliorated the production of malondialdehyde(MDA)(p<0.05 or p<0.01).Importantly,G-Rg3 exhibited the protective potential against HS-induced injury not only suppressing the protein levels of heme oxygenase-1(HO-1),hypoxia-inducible factor-1α(HIF-1α),and heat shock protein 70(HSP70)but also modulating the Bcl-2 family(p<0.01 or p<0.001)and activation of mitogen-activated protein kinase(MAPK)signaling pathways(p<0.01).For most of the parameters tested,the HS+G-Rg3(10 mg/kg)group exhibited potent effects compared with those exhibited by the low dose(5 mg/kg)group.In conclusion,the present study demonstrated that G-Rg3 exerted protective effects against HS-induced testicular dysfunction via inhibiting the MAPK-mediated oxidative stress and apoptosis in mice. 展开更多
关键词 20(R)-ginsenoside Rg3 Heat stress Spermatogenic damage Oxidative stress MAPK
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3D random Voronoi grain-based models for simulation of brittle rock damage and fabric-guided micro-fracturing 被引量:31
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作者 E.Ghazvinian M.S.Diederichs R.Quey 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2014年第6期506-521,共16页
A grain-based distinct element model featuring three-dimensional (3D) Voronoi tessellations (randompoly-crystals) is proposed for simulation of crack damage development in brittle rocks. The grainboundaries in pol... A grain-based distinct element model featuring three-dimensional (3D) Voronoi tessellations (randompoly-crystals) is proposed for simulation of crack damage development in brittle rocks. The grainboundaries in poly-crystal structure produced by Voronoi tessellations can represent flaws in intact rockand allow for numerical replication of crack damage progression through initiation and propagation ofmicro-fractures along grain boundaries. The Voronoi modelling scheme has been used widely in the pastfor brittle fracture simulation of rock materials. However the difficulty of generating 3D Voronoi modelshas limited its application to two-dimensional (2D) codes. The proposed approach is implemented inNeper, an open-source engine for generation of 3D Voronoi grains, to generate block geometry files thatcan be read directly into 3DEC. A series of Unconfined Compressive Strength (UCS) tests are simulated in3DEC to verify the proposed methodology for 3D simulation of brittle fractures and to investigate therelationship between each micro-parameter and the model's macro-response. The possibility of numericalreplication of the classical U-shape strength curve for anisotropic rocks is also investigated innumerical UCS tests by using complex-shaped (elongated) grains that are cemented to one another alongtheir adjoining sides. A micro-parameter calibration procedure is established for 3D Voronoi models foraccurate replication of the mechanical behaviour of isotropic and anisotropic (containing a fabric) rocks. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved. 展开更多
关键词 Numerical modelling 3D Voronoi tessellation Discrete element method Grain-based model Crack damage thresholds Fabric-guided micro-fracturing Anisotropy
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Overexpression of fibroblast growth factor 13 ameliorates amyloid-β-induced neuronal damage 被引量:2
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作者 Ruo-Meng Li Lan Xiao +2 位作者 Ting Zhang Dan Ren Hong Zhu 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第6期1347-1353,共7页
Previous studies have shown that fibroblast growth factor 13 is downregulated in the brain of both Alzheimer’s disease mouse models and patients,and that it plays a vital role in the learning and memory.However,the u... Previous studies have shown that fibroblast growth factor 13 is downregulated in the brain of both Alzheimer’s disease mouse models and patients,and that it plays a vital role in the learning and memory.However,the underlying mechanisms of fibroblast growth factor 13 in Alzheimer’s disease remain unclear.In this study,we established rat models of Alzheimer’s disease by stereotaxic injection of amyloid-β(Aβ_(1-42))-induced into bilateral hippocampus.We also injected lentivirus containing fibroblast growth factor 13 into bilateral hippocampus to overexpress fibroblast growth factor 13.The expression of fibroblast growth factor 13 was downregulated in the brain of the Alzheimer’s disease model rats.After overexpression of fibroblast growth factor 13,learning and memory abilities of the Alzheimer’s disease model rats were remarkably improved.Fibroblast growth factor 13 overexpression increased brain expression levels of oxidative stress-related markers glutathione,superoxide dismutase,phosphatidylinositol-3-kinase,AKT and glycogen synthase kinase 3β,and anti-apoptotic factor BCL.Furthermore,fibroblast growth factor 13 overexpression decreased the number of apoptotic cells,expression of pro-apoptotic factor BAX,cleaved-caspase 3 and amyloid-βexpression,and levels of tau phosphorylation,malondialdehyde,reactive oxygen species and acetylcholinesterase in the brain of Alzheimer’s disease model rats.The changes were reversed by the phosphatidylinositol-3-kinase inhibitor LY294002.These findings suggest that overexpression of fibroblast growth factor 13 improved neuronal damage in a rat model of Alzheimer’s disease through activation of the phosphatidylinositol-3-kinase/AKT/glycogen synthase kinase 3βsignaling pathway. 展开更多
关键词 AKT Alzheimer’s disease amyloid-β apoptosis cognitive dysfunction fibroblast growth factor 13 glycogen synthase kinase 3β neuronal damage oxidative stress phosphatidylinositol-3-kinase
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Photosynthetic Toxicity and Oxidative Damage Induced by nano-Fe3O4 on <i>Chlorella vulgaris</i>in Aquatic Environment 被引量:1
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作者 Xiaoxiao Chen Xing Zhu +3 位作者 Rui Li Hanchao Yao Zhisong Lu Xu Yang 《Open Journal of Ecology》 2012年第1期21-28,共8页
With the rapid development of nanotechnology and widespread use of nanoproducts, concerns have arisen regarding the ecotoxicity of these materials. In this paper, the photosynthetic toxicity and oxidative damage induc... With the rapid development of nanotechnology and widespread use of nanoproducts, concerns have arisen regarding the ecotoxicity of these materials. In this paper, the photosynthetic toxicity and oxidative damage induced by nano Fe3O4 on a model organism, Chlorella vulgaris (C. vulgaris) in aquatic environment, were studied. The results showed that Nano-Fe3O4 was toxic to C. vulgaris and affected its content of chlorophyll a, malonaldehyde and glutathione, CO2 absorption, net photosynthetic rate, superoxide dismutase activity and inhibition of hydroxyl radical generation. At higher concentrations, compared with the control group, the toxicity of nano-Fe3O4 was significantly different. It suggested that nano-Fe3O4 is ecotoxic to C. vulgaris in aquatic environment. 展开更多
关键词 NANO-FE3O4 Chlorella vulgaris PHOTOSYNTHETIC TOXICITY Oxidative damage ECOTOXICITY
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A new method of mesh simplification for 3-Dimension terrain using Laplace operator 被引量:1
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作者 Zuo Wenpin Che Xiangjiu 《Computer Aided Drafting,Design and Manufacturing》 2012年第1期44-48,共5页
This paper proposes a new method to simplify mesh in 3D terrain. The 3D terrain is presented by digital elevation model. First, Laplace operator is introduced to calculate sharp degree of mesh point, which indicates t... This paper proposes a new method to simplify mesh in 3D terrain. The 3D terrain is presented by digital elevation model. First, Laplace operator is introduced to calculate sharp degree of mesh point, which indicates the variation trend of the terrain. Through setting a critical value of sharp degree, feature points are selected. Second, critical mesh points are extracted by an recursive process, and constitute the simplified mesh. Third, the algorithm of linear-square interpolation is employed to restore the characteris- tics of the terrain. Last, the terrain is rendered with color and texture. The experimental results demonstrate that this method can compress data by 16% and the error is lower than 10%. 展开更多
关键词 3-dimension terrain critical mesh point simplified mesh Laplace operator
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DNA polymerase delta interacting protein 3 facilitates the activation and maintenance of DNA damage checkpoint in response to replication stress
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作者 Sufang Zhang Ernest Y.C.Lee +1 位作者 Marietta Y.W.T.Lee Dong Zhang 《Animal Models and Experimental Medicine》 CAS CSCD 2022年第5期461-469,共9页
Background:Replication stress response is crucial for the maintenance of a stable ge-nome.POLDIP3(DNA polymerase delta interacting protein 3)was initially identified as one of the DNA polymeraseδ(Polδ)interacting pr... Background:Replication stress response is crucial for the maintenance of a stable ge-nome.POLDIP3(DNA polymerase delta interacting protein 3)was initially identified as one of the DNA polymeraseδ(Polδ)interacting proteins almost 20 years ago.Using a variety of in vitro biochemical assays,we previously established that POLDIP3 is a key regulator of the enzymatic activity of Polδ.However,the in vivo function of POLDIP3 in DNA replication and DNA damage response has been elusive.Methods:We first generated POLDIP3 knockout(KO)cells using the CRISPR/Cas9 technology.We then investigated its biological functions in vivo using a variety of biochemical and cell biology assays.Results:We showed that although the POLDIP3-KO cells manifest no pronounced defect in global DNA synthesis under nonstress conditions,they are sensitive to a va-riety of replication fork blockers.Intriguingly,we found that POLDIP3 plays a crucial role in the activation and maintenance of the DNA damage checkpoint in response to exogenous as well as endogenous replication stress.Conclusion:Our results indicate that when the DNA replication fork is blocked,POLDIP3 can be recruited to the stalled replication fork and functions to bridge the early DNA damage checkpoint response and the later replication fork repair/restart. 展开更多
关键词 DNA damage checkpoint DNA polymerase delta POLDIP3 replication stress
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Flood and Waterlogging Disaster Damage Evaluation in Middle-Lower Yangtze River by 3S technology
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作者 ZHAN Xiao-guoEngineer, Yangtze River Scientific Research Institute, Wuhan 430010,China TAN De-baoSenior Engineer, Yangtze River Scientific Research Institute, Wuhan 430010,China 《人民长江》 北大核心 2001年第S1期50-52,共3页
The evaluation method, model and process for the flood and waterlogging disaster condition by GIS,RS and GPS technology and the method for setting up disaster condition database, dyke database and historical disaster ... The evaluation method, model and process for the flood and waterlogging disaster condition by GIS,RS and GPS technology and the method for setting up disaster condition database, dyke database and historical disaster damage database are presented. An index of flood damage degree(FDD) used to evaluate the relative degree of disaster loss and divide flood and waterlogging area is suggested. The value of flood damage degree can be calculated as follows :taking the various disaster losses of sample area in a base year as standard value and computing the ratios of various disaster loss values in different areas and years to the standard flood disaster loss values, then summing up the weighted ratios. The computed results are the value of flood damage degree in the every year. The macroscopic flood disaster distribution can be evaluated by the values of flood loss degree. 展开更多
关键词 FLOOD and WATERLOGGING disaster evaluation method 3S(GIS RS GPS) FLOOD damage degree middle-lower reaches of YANGTZE River
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Mitochondrial and nuclear damages and caspase-3 expression in the hippicampal CA3 region of rats with kainic acid induced statuse pilepticus
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作者 Shuhai Tang Jianying Sun Xiaojun Pan Li Zhang 《Neural Regeneration Research》 SCIE CAS CSCD 2006年第7期577-580,共4页
BACKGROUND: Some scholars believed that the neuronal injury after status epilepticus is apoptosis, the main evidence is the changes of expressions of various apoptosis related genes, such as immediate-early gene, p53 ... BACKGROUND: Some scholars believed that the neuronal injury after status epilepticus is apoptosis, the main evidence is the changes of expressions of various apoptosis related genes, such as immediate-early gene, p53 gene and genes of bcl-2 family, etc. But there is still no ultrastructural evidence for apoptosis. OBJECTIVE: To observe the ultrastructural damages of mitochondrion and nucleus and the changes of caspase expression in neurons of hippocampal CA3 region in rats with status epilepticus induced by kainic acid. DESIGN: A randomized controlled study. SETTING: Department of Anesthesiology and Department of Neurology, Qilu Hospital of Shandong University. MATERIALS: Seventy-five adult male Wistar rats of 250-300 g, clean degree, were provided by the experimental animal center of Shandong University. Kainic acid was purchased from Sigma Company (USA); rabbit anti-rat polyclonal antibody caspase-3 from Santa Cruz Company (USA). METHODS: The experiments were carried out in the Department of Anesthesiology, Qilu Hospital of Shandong University from October 2005 to February 2006. ① The 75 rats were randomly divided into experimental group (n =45) and control group (n =30). ② Model establishment, convulsion grading and the judging standards for status epilepticus: Rats in the experimental group were given intraperitoneal injection of kainic acid (10 mg/kg), and those in the control group were injected with saline of the same volume. The time of seizure was recorded and their behavioral manifestations were observed, and the seizure was terminated by intraperitoneal injection of diazepam (10 mg/kg). ③ Observation under electron microscope: At 3, 12 and 24 hours after status epilepticus respectively, bilateral hippocampal tissues were taken out, semithin sections of about 75 nm were prepared after fixation, dehydration and embedding, and then observed under H-800 transmission electron microscope. ④ Immunohistochemical detection: Bilateral hippocampi were removed at 3, 12 and 24 hours after status epilepticus respectively, the fixation, dehydration, transparence, wax immersion and embedding were performed, then serial sections of CA3 region were immunohistochemically determined by the SABC method. Leica QWinV3 image analytical software was applied, then the average number and average gray value of positive cells were calculated. MAIN OUTCOME MEASURES: Results of observation under electron microscope, that of immunohistochemical staining of neurons in hippocampal CA3 region; Comparison of number of caspase-3 positive cells and gray value. RESULTS: All the 75 Wistar rats were involved in the analysis of results. ① Results of observation under electron microscope: At 3 hours after status epilepticus, swelling crista and membranous disintegration were observed under electron microscope. At 24 hours, obvious nuclear changes occurred, and manifested as the side-aggegation of chromatins. ② Results of immunohistochemical detection: In the experimental group, the number of caspase-3 positive cells at 3 hours after status epilepticus had no obvious difference as compared with that in the control group (P > 0.05); At 12 hours, the number and gray value of caspase-3 positive cells in the experimental group were higher than those in the control group (10.49±0.68 vs. 5.33±0.43; 45.57±2.27 vs. 19.79±0.33, P < 0.05), the same results were also observed at 24 hours (37.36±0.57 vs. 5.12±0.47; 115.24±1.22 vs. 18.73±0.42, P < 0.01). CONCLUSION: In the rat models of status epilepticus induced by kainic acid, mitochondrial damage was earlier than the increase of caspase-3 expression and nuclear changes, which suggested that mitochondrion was the key link for the neuronal death after status epilepticus. 展开更多
关键词 acid Mitochondrial and nuclear damages and caspase-3 expression in the hippicampal CA3 region of rats with kainic acid induced statuse pilepticus CA
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INVESTIGATION OF SURFACE DAMAGE OF LiNbO_3 IMPLANTED BY Ti ION
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作者 ZHOU Jian-Hua, YOU Bo-Qiang, ZHANG Liang-Ying, YAO Xi Electronic Materials Research Laboratory. Xi’an Jiaotong University, Xi’an, 710049, China. 《真空科学与技术学报》 EI CAS CSCD 1992年第Z1期159-162,共4页
In this paper, damages and annealing effects of X,Y and Z cut LiNbO-3 implanted by 350keV high energy Ti (1.5 x 10<sup>17</sup> / cm<sup>2</sup>) are studied. The surface damages of X,Y cut pla... In this paper, damages and annealing effects of X,Y and Z cut LiNbO-3 implanted by 350keV high energy Ti (1.5 x 10<sup>17</sup> / cm<sup>2</sup>) are studied. The surface damages of X,Y cut plates are nearly amorphous, but the surface damage of Z cut does not reach saturation. Radiation damage is mainly due to Nb moving atoms and Ti atoms occupy the interstitial sites. By annealing the sample at 1000℃, most damage is removed from the boundary between implanted layer and LiNbO<sub>3</sub> base to surface. 展开更多
关键词 TI INVESTIGATION OF SURFACE damage OF LiNbO3 IMPLANTED BY Ti ION
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Cicada(Magicicada)Tree Damage Detection Based on UAV Spectral and 3D Data
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作者 Angela Maria Klein Hentz Michael P.Strager 《Natural Science》 2018年第1期31-44,共14页
The periodical cicadas appear in regions of the United States in intervals of 13 or 17 years. During these intervals, deciduous trees are often impacted by the small cuts and eggs they lay in the outer branches which ... The periodical cicadas appear in regions of the United States in intervals of 13 or 17 years. During these intervals, deciduous trees are often impacted by the small cuts and eggs they lay in the outer branches which soon die off. Because this is such an infrequent occurrence and it is?so difficult to assess the damage across large forested areas, there is little information about the extent of this impact. The use of remote sensing techniques has been proven to be useful in forest health management to monitor large areas. In addition, the use of Unmanned Aerial Vehicles (UAVs) has become a valuable tool for analysis. In this study,?we evaluated the impact of the periodical cicada occurrence on a mixed hardwood forest using UAV imagery.?The goal was to evaluate the potential of this technology as a tool for forest health monitoring. We classified the cicada impact using two Maximum Likelihood classifications, one using only the high resolution spectral derived from leaf-on imagery (MLC 1), and in the second we included the Canopy Height Model (CHM)—derived from?leaf-on Digital Surface Model (DSM) and leaf-off Digital Terrain Model (DTM)—information in the classification process (MLC 2). We evaluated the damage percentage in relation to the total forest area in 15 circular plots and observed a range from 1.03%?-22.23% for MLC 1, and 0.02%?-?10.99% for MLC 2. The accuracy of the classification was 0.35 and 0.86, for MLC 1 and MLC 2, based on the kappa index. The results allow us to highlight the importance of combining spectral and 3D information to evaluate forest health features. We believe this approach can be applied in many forest monitoring objectives in order to?detect disease or pest impacts. 展开更多
关键词 PHOTOGRAMMETRY Insect damage 3D Dense Point Cloud
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肠道菌群通过去乙酰化酶3激活单磷酸腺苷活化的蛋白激酶/雷帕霉素信号通路对脓毒症心肌炎和心肌细胞线粒体损伤的影响 被引量:3
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作者 林爽 翟京宇 罗彬 《临床内科杂志》 CAS 2024年第4期278-281,共4页
目的探讨正常肠道粪菌移植(FMT)对脓毒症心肌炎和心肌细胞线粒体损伤的改善作用与机制。方法将40只SD大鼠随机分为盲肠结扎穿孔术(CLP)建立的脓毒症模型组(CLP组)、假手术对照组(sham组)、FMT治疗组(CLP+FMT组)及FMT联合去乙酰化酶3(SIR... 目的探讨正常肠道粪菌移植(FMT)对脓毒症心肌炎和心肌细胞线粒体损伤的改善作用与机制。方法将40只SD大鼠随机分为盲肠结扎穿孔术(CLP)建立的脓毒症模型组(CLP组)、假手术对照组(sham组)、FMT治疗组(CLP+FMT组)及FMT联合去乙酰化酶3(SIRT3)抑制剂(3-TYP)治疗组(CLP+FMT+3-TYP组),每组各10只。采用HE染色观察大鼠心肌组织的病理变化,采用ELISA检测大鼠血液中IL-1β、IL-6、肿瘤坏死因子(TNF)-α的表达水平,采用Western blot检测大鼠心肌组织中IL-1β、NOD样受体热蛋白结构域相关蛋白3(NLRP3)、去乙酰化酶3(SIRT3)、单磷酸腺苷活化的蛋白激酶(AMPK)、磷酸化AMPK(p-AMPK)、雷帕霉素(mTOR)及p-mTOR表达水平,采用透射电镜观察大鼠心肌细胞线粒体形态,采用流式细胞术分析大鼠心肌细胞的线粒体膜电位变化。结果与sham组比较,CLP组、CLP+FMT组、CLP+FMT+3-TYP组心肌组织SIRT3和p-mTOR表达水平均显著降低,而心肌组织p-AMPK和血液中IL-1β、IL-6及TNF-α的表达水平均显著增加;与CLP组比较,CLP+FMT组心肌组织SIRT3和p-mTOR的表达水平均显著增加,而心肌组织p-AMPK和血液中IL-1β、IL-6及TNF-α的表达水平均显著降低;与CLP+FMT组比较,CLP+FMT+3-TYP组心肌组织SIRT3和p-mTOR的表达水平均显著降低,而心肌组织中p-AMPK和血液中IL-1β、IL-6及TNF-α的表达水平均显著增加;与sham组比较,CLP组线粒体膜电位的红/绿荧光强度比值显著下降;与CLP组比较,CLP+FMT组线粒体膜电位的红/绿荧光强度比值显著增加;与CLP+FMT组比较,CLP+FMT+3-TYP组线粒体膜电位的红/绿荧光强度比值显著下降(P<0.05)。结论肠道菌群通过SIRT3激活AMPK/mTOR信号通路对脓毒症心肌炎和心肌细胞线粒体损伤均有改善作用。 展开更多
关键词 肠道粪菌移植 脓毒症心肌炎 线粒体损伤 去乙酰化酶3 单磷酸腺苷活化的蛋白激酶/雷帕霉素信号通路
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