Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during ...Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during the rocking process.An innovative RW with a curved interface is proposed to prevent interfacial corners from producing local damage,enhancing its earthquake resilient performance(ERP).The precast wall panel with a curved interface is assembled into an integral self-centering hybrid rocking wall(SCRW)by two post-tensioned unbonded prestressed tendons.Moreover,two ordinary energy dissipation steel rebars and two shear reinforcements are arranged to increase the energy dissipation capacity and lateral resistance.Two SCRW specimens and one monolithic reinforced concrete(RC)shear wall(SW)were tested under pseudo-static loading to compare the ERPs of the proposed SCRW and the SW,focusing on studying the effect of the curved interface on the SCRW.The key resilient performance of rocking effects,failure modes,and hysteretic properties of the SCRW were explored.The results show that nonlinear deformations of the SCRW are concentrated along the interface between the SCRW and the foundation,avoiding damage within the SCRW.The restoring force provided by the prestressed tendons can effectively realize self-centering capacity with small residual deformation,and the resilient performance of the SCRW is better than that of monolithic SW.In addition,the curved interface of the SCRW makes the rocking center change and move inward,partially relieving the stress concentration and crush of concrete.The rocking range of the rocking center is about 41.4%of the width of the SCRW.展开更多
Hepatocellular carcinoma(HCC)is a leading cause of death worldwide.Current therapies are effective for HCC patients with early disease,but many patients suffer recurrence after surgery and have a poor response to chem...Hepatocellular carcinoma(HCC)is a leading cause of death worldwide.Current therapies are effective for HCC patients with early disease,but many patients suffer recurrence after surgery and have a poor response to chemotherapy.Therefore,new therapeutic targets are needed.We analyzed gene expression profiles between HCC tissues and normal adjacent tissues from public databases and found that the expression of genes involved in lipid metabolism was significantly different.The analysis showed that AKR1C3 was upregulated in tumors,and high AKR1C3 expression was associated with a poorer prognosis in HCC patients.In vitro,assays demonstrated that the knockdown of AKR1C3 or the addition of the AKR1C3 inhibitor indomethacin suppressed the growth and colony formation of HCC cell lines.Knockdown of AKR1C3 in Huh7 cells reduced tumor growth in vivo.To explore the mechanism,we performed pathway enrichment analysis,and the results linked the expression of AKR1C3 with prostaglandin F2 alpha(PGF2a)downstream target genes.Suppression of AKR1C3 activity reduced the production of PGF2a,and supplementation with PGF2a restored the growth of indomethacin-treated Huh7 cells.Knockdown of the PGF receptor(PTGFR)and treatment with a PTGFR inhibitor significantly reduced HCC growth.We showed that indomethacin potentiated the sensitivity of Huh7 cells to sorafenib.In summary,our results indicate that AKR1C3 upregulation may promote HCC growth by promoting the production of PGF2α,and suppression of PTGFR limited HCC growth.Therefore,targeting the AKR1C3-PGF2a-PTGFR axis may be a new strategy for the treatment of HCC.展开更多
To clarify the formation and distribution of feldspar dissolution pores and predict the distribution of high-quality reservoir in gravity flow sandstone of the 7^(th) member of Triassic Yanchang Formation(Chang 7 Memb...To clarify the formation and distribution of feldspar dissolution pores and predict the distribution of high-quality reservoir in gravity flow sandstone of the 7^(th) member of Triassic Yanchang Formation(Chang 7 Member)in the Ordos Basin,thin sections,scanning electron microscopy,energy spectrum analysis,X-ray diffraction whole rock analysis,and dissolution experiments are employed in this study to investigate the characteristics and control factors of feldspar dissolution pores.The results show that:(1)Three types of diagenetic processes are observed in the feldspar of Chang 7 sandstone in the study area:secondary overgrowth of feldspar,replacement by clay and calcite,and dissolution of detrital feldspar.(2)The feldspar dissolution of Chang 7 tight sandstone is caused by organic acid,and is further affected by the type of feldspar,the degree of early feldspar alteration,and the buffering effect of mica debris on organic acid.(3)Feldspars have varying degrees of dissolution.Potassium feldspar is more susceptible to dissolution than plagioclase.Among potassium feldspar,orthoclase is more soluble than microcline,and unaltered feldspar is more soluble than early kaolinized or sericitized feldspar.(4)The dissolution experiment demonstrated that the presence of mica can hinder the dissolution of feldspar.Mica of the same mass has a significantly stronger capacity to consume organic acids than feldspar.(5)Dissolution pores in feldspar of Chang 7 Member are more abundant in areas with low mica content,and they improve the reservoir physical properties,while in areas with high mica content,the number of feldspar dissolution pores decreases significantly.展开更多
BACKGROUND MicroRNAs(miRNAs)regulate gene expression and play a critical role in cancer physiology.However,there is still a limited understanding of the function and regulatory mechanism of miRNAs in gastric cancer(GC...BACKGROUND MicroRNAs(miRNAs)regulate gene expression and play a critical role in cancer physiology.However,there is still a limited understanding of the function and regulatory mechanism of miRNAs in gastric cancer(GC).AIM To investigate the role and molecular mechanism of miRNA-145-5p(miR145-5p)in the progression of GC.METHODS Real-time polymerase chain reaction(RT-PCR)was used to detect miRNA expression in human GC tissues and cells.The ability of cancer cells to migrate and invade was assessed using wound-healing and transwell assays,respectively.Cell proliferation was measured using cell counting kit-8 and colony formation assays,and apoptosis was evaluated using flow cytometry.Expression of the epithelial-mesenchymal transition(EMT)-associated protein was determined by Western blot.Targets of miR-145-5p were predicated using bioinformatics analysis and verified using a dual-luciferase reporter system.Serpin family E member 1(SERPINE1)expression in GC tissues and cells was evaluated using RT-PCR and immunohistochemical staining.The correlation between SERPINE1 expression and overall patient survival was determined using Kaplan-Meier plot analysis.The association between SERPINE1 and GC progression was also tested.A rescue experiment of SERPINE1 overexpression was conducted to verify the relationship between this protein and miR-145-5p.The mechanism by which miR-145-5p influences GC progression was further explored by assessing tumor formation in nude mice.RESULTS GC tissues and cells had reduced miR-145-5p expression and SERPINE1 was identified as a direct target of this miRNA.Overexpression of miR-145-5p was associated with decreased GC cell proliferation,invasion,migration,and EMT,and these effects were reversed by forcing SERPINE1 expression.Kaplan-Meier plot analysis revealed that patients with higher SERPINE1 expression had a shorter survival rate than those with lower SERPINE1 expression.Nude mouse tumorigenesis experiments confirmed that miR-145-5p targets SERPINE1 to regulate extracellular signal-regulated kinase-1/2(ERK1/2).CONCLUSION This study found that miR-145-5p inhibits tumor progression and is expressed in lower amounts in patients with GC.MiR-145-5p was found to affect GC cell proliferation,migration,and invasion by negatively regulating SERPINE1 levels and controlling the ERK1/2 pathway.展开更多
In this editorial we comment on the article by Wei et al,published in the recent issue of the World Journal of Clinical Oncology.The authors investigated the role of Transmembrane 9 superfamily member 1(TM9SF1)protein...In this editorial we comment on the article by Wei et al,published in the recent issue of the World Journal of Clinical Oncology.The authors investigated the role of Transmembrane 9 superfamily member 1(TM9SF1)protein in bladder cancer(BC)carcinogenesis.Lentiviral vectors were used to achieve silencing or overexpression of TM9SF1 gene in three BC cell lines.These cell lines were then subject to cell counting kit 8,wound-healing assay,transwell assay,and flow cytometry.Proliferation,migration,and invasion of BC cells were increased in cell lines subjected to TM9SF1 overexpression.TM9SF1 silencing inhibited proliferation,migration and invasion of BC cells.The authors conclude that TM9SF1 may be an oncogene in bladder cancer pathogenesis.展开更多
BACKGROUND Alzheimer’s disease(AD)is a neurodegenerative condition characterized by oxidative stress and neuroinflammation.Tanshinone ⅡA(Tan-ⅡA),a bioactive compound isolated from Salvia miltiorrhiza plants,has sho...BACKGROUND Alzheimer’s disease(AD)is a neurodegenerative condition characterized by oxidative stress and neuroinflammation.Tanshinone ⅡA(Tan-ⅡA),a bioactive compound isolated from Salvia miltiorrhiza plants,has shown potential neuroprotective effects;however,the mechanisms underlying such a function remain unclear.AIM To investigate potential Tan-ⅡA neuroprotective effects in AD and to elucidate their underlying mechanisms.METHODS Hematoxylin and eosin staining was utilized to analyze structural brain tissue morphology.To assess changes in oxidative stress and neuroinflammation,we performed enzyme-linked immunosorbent assay and western blotting.Additionally,the effect of Tan-ⅡA on AD cell models was evaluated in vitro using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.Genetic changes related to the long non-coding RNA(lncRNA)nuclear-enriched abundant transcript 1(NEAT1)/microRNA(miRNA,miR)-291a-3p/member RAS oncogene family Rab22a axis were assessed through reverse transcription quantitative polymerase chain reaction.RESULTS In vivo,Tan-ⅡA treatment improved neuronal morphology and attenuated oxidative stress and neuroinflammation in the brain tissue of AD mice.In vitro experiments showed that Tan-ⅡA dose-dependently ameliorated the amyloid-beta 1-42-induced reduction of neural stem cell viability,apoptosis,oxidative stress,and neuroinflammation.In this process,the lncRNA NEAT1-a potential therapeutic target-is highly expressed in AD mice and downregulated via Tan-ⅡA treatment.Mechanistically,NEAT1 promotes the transcription and translation of Rab22a via miR-291a-3p,which activates nuclear factor kappa-B(NF-κB)signaling,leading to activation of the pro-apoptotic B-cell lymphoma 2-associated X protein and inhibition of the anti-apoptotic B-cell lymphoma 2 protein,which exacerbates AD.Tan-ⅡA intervention effectively blocked this process by inhibiting the NEAT1/miR-291a-3p/Rab22a axis and NF-κB signaling.CONCLUSION This study demonstrates that Tan-ⅡA exerts neuroprotective effects in AD by modulating the NEAT1/miR-291a-3p/Rab22a/NF-κB signaling pathway,serving as a foundation for the development of innovative approaches for AD therapy.展开更多
A new type of beam-to-column connection for steel moment flames, designated as a "self-centering connection," is studied. In this connection, bolted top-and-seat angles, and post-tensioned (PT) high-strength steel...A new type of beam-to-column connection for steel moment flames, designated as a "self-centering connection," is studied. In this connection, bolted top-and-seat angles, and post-tensioned (PT) high-strength steel strands running along the beam are used. The PT strands tie the beam flanges on the column flange to resist moment and provide self-centering force. After an earthquake, the connections have zero deformation, and can be restored to their original status by simply replacing the angles. Four full-scale connections were tested under cyclic loading. The strength, energy-dissipation capacity, hysteresis curve, as well as angles and PT strands behavior of the connections are investigated. A general FEM analysis program called ABAQUS 6.9 is adopted to model the four test specimens. The numerical and test results match very well. Both the test and analysis results suggest that: (1) the columns and beams remain elastic while the angles sustain plastic deformations for energy dissipation when the rotation of the beam related to the column equals 0.05 tad, (2) the energy dissipation capacity is enhanced when the thickness of the angle is increased, and (3) the number of PT strands has a significant influence on the behavior of the connections, whereas the distance between the strands is not as important to the performance of the connection.展开更多
The seismic performance of a self-centering precast reinforced concrete (RC) frame with shear walls was investigated in this paper. The lateral force resistance was provided by self-centering precast RC shear walls ...The seismic performance of a self-centering precast reinforced concrete (RC) frame with shear walls was investigated in this paper. The lateral force resistance was provided by self-centering precast RC shear walls (SPCW), which utilize a combination ofunbonded prestressed post-tensioned (PT) tendons and mild steel reinforcing bars for flexural resistance across base joints. The structures concentrated deformations at the bottom joints and the unbonded PT tendons provided the self-centering restoring force. A 1/3-scale model of a five-story self-centering RC frame with shear walls was designed and tested on a shake-table under a series of bi-directional earthquake excitations with increasing intensity. The acceleration response, roof displacement, inter-story drifts, residual drifts, shear force ratios, hysteresis curves, and local behaviour of the test specimen were analysed and evaluated. The results demonstrated that seismic performance of the test specimen was satisfactory in the plane of the shear wall; however, the structure sustained inter-story drift levels up to 2.45%. Negligible residual drifts were recorded after all applied earthquake excitations. Based on the shake-table test results, it is feasible to apply and popularize a self-centering precast RC frame with shear walls as a structural system in seismic regions.展开更多
This paper presents the results of a parametric study of self-centering seismic retrofit schemes for reinforced concrete (RC) frame buildings. The self-centering retrofit system features flag-shaped hysteresis and min...This paper presents the results of a parametric study of self-centering seismic retrofit schemes for reinforced concrete (RC) frame buildings. The self-centering retrofit system features flag-shaped hysteresis and minimal residual deformation. For comparison purpose,an alternate seismic retrofit scheme that uses a bilinear-hysteresis retrofit system such as buckling-restrained braces (BRB) is also considered in this paper. The parametric study was carried out in a single-degree-of-freedom (SDOF) system framework since a multi-story building structure may be idealized as an equivalent SDOF system and investigation of the performance of this equivalent SDOF system can provide insight into the seismic response of the multi-story building. A peak-oriented hysteresis model which can consider the strength and stiffness degradation is used to describe the hysteretic behavior of RC structures. The parametric study involves two key parameters -the strength ratio and elastic stiffness ratio between the seismic retrofit system and the original RC frame. An ensemble of 172 earthquake ground motion records scaled to the design basis earthquake in California with a probability of exceedance of 10% in 50 years was constructed for the simulation-based parametric study. The effectiveness of the two seismic retrofit schemes considered in this study is evaluated in terms of peak displacement ratio,peak acceleration ratio,energy dissipation demand ratio and residual displacement ratio between the SDOF systems with and without retrofit. It is found from this parametric study that RC structures retrofitted with the self-centering retrofit scheme (SCRS) can achieve a seismic performance level comparable to the bilinear-hysteresis retrofit scheme (BHRS) in terms of peak displacement and energy dissipation demand ratio while having negligible residual displacement after earthquake.展开更多
Firstly, in view of the respective defects of existing self-centering devices for vehicle suspension height, the design scheme of the proposed mechanical self-centering device for suspension height is described. Takin...Firstly, in view of the respective defects of existing self-centering devices for vehicle suspension height, the design scheme of the proposed mechanical self-centering device for suspension height is described. Taking the rear suspension of a certain light bus as a research example, the structures and parameters of the novel device are designed and ascertained. Then, the road excitation models, the performance evaluation indexes and the half-vehicle model are built, the simulation outputs of time and frequency domain are obtained with the road excitations of random and pulse by using MATLAB/Simulink software. So the main characteristics of the self-centering suspension are presented preliminarily. Finally, a multi-objective parameter design optimization model for the self-centering device is built by weighted sum approach, and optimal solution is obtained by adopting complex approach. The relevant choosing-type parameters for self-centering device components are deduced by using discrete variable optimal method, and the optimal results are verified and analyzed. So the performance potentials of the self-centering device are exerted fully in condition of ensuring overall suspension performances.展开更多
A new type of steel moment resisting frame with bottom flange friction devices (BFFDs) has been developed to provide self-centering capacity and energy dissipation, and to reduce permanent deformations under earthqu...A new type of steel moment resisting frame with bottom flange friction devices (BFFDs) has been developed to provide self-centering capacity and energy dissipation, and to reduce permanent deformations under earthquakes. This paper presents a numerical simulation of self-centering beam-column connections with BFFDs, in which the gap opening/closing at the beam-column interfaces is simulated by using pairs of zero-length elements with compression-only material properties, and the energy dissipation due to friction is simulated by using truss elements with specified hysteretic behavior. In particular, the effect of the friction bolt bearing against the slotted plate in the BFFDs was modeled, so that the increase in lateral force and the loss of friction force due to the bolt bearing could be taken into account. Parallel elastic-perfectly plastic gap (ElasticPPGap) materials in the Open System for Earthquake Engineering Simulation (OpenSees) were used with predefined gaps to specify the sequence that each bolt went into the bearing and the corresponding increase in bending stiffness. The MinMax material in OpenSees is used to specify the minimum and maximum values of strains of the ElasticPPGap materials. To consider the loss of friction force due to bok bearing, a number of parallel hysteretic materials were used, and the failure of these materials in sequence simulated the gradual loss of friction force. Analysis results obtained by using the proposed numerical model are discussed and compared with the test results under cyclic loadings and the seismic loading, respectively.展开更多
The seismic performance of a five-story,four-bay,self-centering precast reinforced concrete frame(SC-RCF),which was redesigned using the direct displacement-based design method,was analytically investigated.The analyt...The seismic performance of a five-story,four-bay,self-centering precast reinforced concrete frame(SC-RCF),which was redesigned using the direct displacement-based design method,was analytically investigated.The analytical model of the overall structure was developed in OpenSees.The multi-spring contact element was adopted to simulate gap open-close behavior at connection interfaces.The limit states of external mild steel dampers and unbonded post-tensioning strands were considered.Static pushover analyses were performed up to the roof drift of 10%.The nonlinear dynamic responses under four groups of ground motions(with different fault distances and site conditions)at six hazard levels(from the service to the very rare earthquake(VRE))were compared.Incremental dynamic analyses were implemented to quantify the structural collapse risk.The results showed that the structural responses of SC-RCF were satisfactory under all levels of earthquakes.The collapse safety of the structure under earthquakes up to VRE1 was adequate,while the structure would collapse to a large extent under VRE2 and VRE3.展开更多
Self-centering earthquake-resistant structures have received increased attention due to their ability to reduce post-earthquake residual deformations and,thus,repair time and cost.This stimulated the development of re...Self-centering earthquake-resistant structures have received increased attention due to their ability to reduce post-earthquake residual deformations and,thus,repair time and cost.This stimulated the development of recentering shape memory alloy(SMA)dampers that use superelastic nitinol wires to dissipate energy and self-center the structure.However,there are still a few case studies applications on full-scale RC buildings in the literature.Moreover,general guidelines or even simplified approaches for the practical design of SMA damped braces are still lacking.This paper focuses on evaluating the effect of using self-centering shape memory alloy dampers for buckling-restrained braces applied for the seismic retrofit of a complex RC building structure.A design method originally proposed for elastoplastic dampers was implemented to size the SMA dampers to be placed on selected spans and stories of a building.The effectiveness of the design procedure was demonstrated by nonlinear time-history analyses under different sets of earthquake strong ground motions.The analysis results show that the recentering shape memory alloy bracing system is effective in limiting the maximum transient inter-story drifts and reducing the residual inter-story drifts after strong seismic events,due to its excellent recentering behavior together with its not negligible energy dissipation capacity.展开更多
Tubular members subject to combined pitting corrosion and crack damage were numerically studied to clarify the reduction of ultimate strength and failure behavior,based on numerical models validated against available ...Tubular members subject to combined pitting corrosion and crack damage were numerically studied to clarify the reduction of ultimate strength and failure behavior,based on numerical models validated against available experi-ments.The effects of length,location and inclined angle of a crack under combined damage were studied to disclose the mechanism of interaction between the crack and corrosion pits.The methods,named as linear superposition directly accumulating the effects of solo crack and solo pitting damage,as well as crack projection transferring an inclined crack to a transverse one,were discussed and verified in the view of assessing ultimate strength of tubular members with combined damage.It was shown that the former is practical but complex while the next always over-estimates the residual strength.Besides,the location and inclined angle of a crack have a subtle effect on the reduction of ultimate strength under combined damage,especially at higher level of pitting damage,due to the synergistic effect between corrosion pits and cracks.Such effect can lead to early occurrence of plasticity and local buckling by inducing stress interaction between crack tips and pits,and causing more significant strength reduction compared with a solo type of damage.A practical method was proposed to determine the loss ratio of cross-sectional area on the equivalent weakest section of a damaged member.Based on the loss ratio,a formula was presented to predict the ultimate strength of damaged members with combined damage,showing good applicability.展开更多
To explore the genesis of the laminated calcite veins developed in the black shale of Chang 73 submember of the Ordos Basin,the petrology,microstructure and geochemistry of calcite veins are studied using thin section...To explore the genesis of the laminated calcite veins developed in the black shale of Chang 73 submember of the Ordos Basin,the petrology,microstructure and geochemistry of calcite veins are studied using thin sections,fluid inclusions,trace elements and isotopic geochemistry.The source,the time of formation,the mechanism of formation,and the dynamic background of the veins are discussed.The veins are mostly made up of calcite,mixed with lenticular or spindle-shape solid wall rock inclusions.Three structures are identified in the calcite minerals:fibrous,rhombic cleavage,and wedge-like structure.Trace elements and isotopes of carbon and oxygen confirm that the calcite veins were formed from a high density hydrothermal fluid.It is assumed that calcite veins formed prior to wall rock consolidation during the formation of the Qinling Orogenic Belt in the Middle and Late Triassic.The results show that the sedimentary sources of Chang 73 submember were influenced by hydrothermal materials besides terrigenous detritus.The fibrous calcite is different from the fibrous calcite reported in the morphology and mechanism of formation.In this way,the research complements and improves the morphology and the mechanism of formation of fibrous calcite.展开更多
According to the theory of sequence stratigraphy based on continental transgressive-regressive(T-R)cycles,a 500 m continuous core taken from the second member of Kongdian Formation(Kong 2 Member)of Paleogene in Well G...According to the theory of sequence stratigraphy based on continental transgressive-regressive(T-R)cycles,a 500 m continuous core taken from the second member of Kongdian Formation(Kong 2 Member)of Paleogene in Well G108-8 in the Cangdong Sag,Bohai Bay Basin,was tested and analyzed to clarify the high-frequency cycles of deep-water fine-grained sedimentary rocks in lacustrine basins.A logging vectorgraph in red pattern was plotted,and then a sequence stratigraphic framework with five-order high-frequency cycles was formed for the fine-grained sedimentary rocks in the Kong 2 Member.The high-frequency cycles of fine-grained sedimentary rocks were characterized by using different methods and at different scales.It is found that the fifth-order T cycles record a high content of terrigenous clastic minerals,a low paleosalinity,a relatively humid paleoclimate and a high density of laminae,while the fifth-order R cycles display a high content of carbonate minerals,a high paleosalinity,a dry paleoclimate and a low density of laminae.The changes in high-frequency cycles controlled the abundance and type of organic matter.The T cycles exhibit relatively high TOC and abundant endogenous organic matters in water in addition to terrigenous organic matters,implying a high primary productivity of lake for the generation and enrichment of shale oil.展开更多
基金National Key Research and Development Program of China under Grant No.2018YFC0705602。
文摘Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during the rocking process.An innovative RW with a curved interface is proposed to prevent interfacial corners from producing local damage,enhancing its earthquake resilient performance(ERP).The precast wall panel with a curved interface is assembled into an integral self-centering hybrid rocking wall(SCRW)by two post-tensioned unbonded prestressed tendons.Moreover,two ordinary energy dissipation steel rebars and two shear reinforcements are arranged to increase the energy dissipation capacity and lateral resistance.Two SCRW specimens and one monolithic reinforced concrete(RC)shear wall(SW)were tested under pseudo-static loading to compare the ERPs of the proposed SCRW and the SW,focusing on studying the effect of the curved interface on the SCRW.The key resilient performance of rocking effects,failure modes,and hysteretic properties of the SCRW were explored.The results show that nonlinear deformations of the SCRW are concentrated along the interface between the SCRW and the foundation,avoiding damage within the SCRW.The restoring force provided by the prestressed tendons can effectively realize self-centering capacity with small residual deformation,and the resilient performance of the SCRW is better than that of monolithic SW.In addition,the curved interface of the SCRW makes the rocking center change and move inward,partially relieving the stress concentration and crush of concrete.The rocking range of the rocking center is about 41.4%of the width of the SCRW.
基金National Yang Ming Chiao Tung University Far Eastern Memorial Hospital Joint Research Programs(NYCU-FEMH 109DN03,110DN06,111DN04,112DN05).
文摘Hepatocellular carcinoma(HCC)is a leading cause of death worldwide.Current therapies are effective for HCC patients with early disease,but many patients suffer recurrence after surgery and have a poor response to chemotherapy.Therefore,new therapeutic targets are needed.We analyzed gene expression profiles between HCC tissues and normal adjacent tissues from public databases and found that the expression of genes involved in lipid metabolism was significantly different.The analysis showed that AKR1C3 was upregulated in tumors,and high AKR1C3 expression was associated with a poorer prognosis in HCC patients.In vitro,assays demonstrated that the knockdown of AKR1C3 or the addition of the AKR1C3 inhibitor indomethacin suppressed the growth and colony formation of HCC cell lines.Knockdown of AKR1C3 in Huh7 cells reduced tumor growth in vivo.To explore the mechanism,we performed pathway enrichment analysis,and the results linked the expression of AKR1C3 with prostaglandin F2 alpha(PGF2a)downstream target genes.Suppression of AKR1C3 activity reduced the production of PGF2a,and supplementation with PGF2a restored the growth of indomethacin-treated Huh7 cells.Knockdown of the PGF receptor(PTGFR)and treatment with a PTGFR inhibitor significantly reduced HCC growth.We showed that indomethacin potentiated the sensitivity of Huh7 cells to sorafenib.In summary,our results indicate that AKR1C3 upregulation may promote HCC growth by promoting the production of PGF2α,and suppression of PTGFR limited HCC growth.Therefore,targeting the AKR1C3-PGF2a-PTGFR axis may be a new strategy for the treatment of HCC.
基金Supported by the National Natural Science Foundation of China(42202176)CNPC-Southwest University of Petroleum Innovation Consortium Cooperation Project(2020CX050103).
文摘To clarify the formation and distribution of feldspar dissolution pores and predict the distribution of high-quality reservoir in gravity flow sandstone of the 7^(th) member of Triassic Yanchang Formation(Chang 7 Member)in the Ordos Basin,thin sections,scanning electron microscopy,energy spectrum analysis,X-ray diffraction whole rock analysis,and dissolution experiments are employed in this study to investigate the characteristics and control factors of feldspar dissolution pores.The results show that:(1)Three types of diagenetic processes are observed in the feldspar of Chang 7 sandstone in the study area:secondary overgrowth of feldspar,replacement by clay and calcite,and dissolution of detrital feldspar.(2)The feldspar dissolution of Chang 7 tight sandstone is caused by organic acid,and is further affected by the type of feldspar,the degree of early feldspar alteration,and the buffering effect of mica debris on organic acid.(3)Feldspars have varying degrees of dissolution.Potassium feldspar is more susceptible to dissolution than plagioclase.Among potassium feldspar,orthoclase is more soluble than microcline,and unaltered feldspar is more soluble than early kaolinized or sericitized feldspar.(4)The dissolution experiment demonstrated that the presence of mica can hinder the dissolution of feldspar.Mica of the same mass has a significantly stronger capacity to consume organic acids than feldspar.(5)Dissolution pores in feldspar of Chang 7 Member are more abundant in areas with low mica content,and they improve the reservoir physical properties,while in areas with high mica content,the number of feldspar dissolution pores decreases significantly.
文摘BACKGROUND MicroRNAs(miRNAs)regulate gene expression and play a critical role in cancer physiology.However,there is still a limited understanding of the function and regulatory mechanism of miRNAs in gastric cancer(GC).AIM To investigate the role and molecular mechanism of miRNA-145-5p(miR145-5p)in the progression of GC.METHODS Real-time polymerase chain reaction(RT-PCR)was used to detect miRNA expression in human GC tissues and cells.The ability of cancer cells to migrate and invade was assessed using wound-healing and transwell assays,respectively.Cell proliferation was measured using cell counting kit-8 and colony formation assays,and apoptosis was evaluated using flow cytometry.Expression of the epithelial-mesenchymal transition(EMT)-associated protein was determined by Western blot.Targets of miR-145-5p were predicated using bioinformatics analysis and verified using a dual-luciferase reporter system.Serpin family E member 1(SERPINE1)expression in GC tissues and cells was evaluated using RT-PCR and immunohistochemical staining.The correlation between SERPINE1 expression and overall patient survival was determined using Kaplan-Meier plot analysis.The association between SERPINE1 and GC progression was also tested.A rescue experiment of SERPINE1 overexpression was conducted to verify the relationship between this protein and miR-145-5p.The mechanism by which miR-145-5p influences GC progression was further explored by assessing tumor formation in nude mice.RESULTS GC tissues and cells had reduced miR-145-5p expression and SERPINE1 was identified as a direct target of this miRNA.Overexpression of miR-145-5p was associated with decreased GC cell proliferation,invasion,migration,and EMT,and these effects were reversed by forcing SERPINE1 expression.Kaplan-Meier plot analysis revealed that patients with higher SERPINE1 expression had a shorter survival rate than those with lower SERPINE1 expression.Nude mouse tumorigenesis experiments confirmed that miR-145-5p targets SERPINE1 to regulate extracellular signal-regulated kinase-1/2(ERK1/2).CONCLUSION This study found that miR-145-5p inhibits tumor progression and is expressed in lower amounts in patients with GC.MiR-145-5p was found to affect GC cell proliferation,migration,and invasion by negatively regulating SERPINE1 levels and controlling the ERK1/2 pathway.
文摘In this editorial we comment on the article by Wei et al,published in the recent issue of the World Journal of Clinical Oncology.The authors investigated the role of Transmembrane 9 superfamily member 1(TM9SF1)protein in bladder cancer(BC)carcinogenesis.Lentiviral vectors were used to achieve silencing or overexpression of TM9SF1 gene in three BC cell lines.These cell lines were then subject to cell counting kit 8,wound-healing assay,transwell assay,and flow cytometry.Proliferation,migration,and invasion of BC cells were increased in cell lines subjected to TM9SF1 overexpression.TM9SF1 silencing inhibited proliferation,migration and invasion of BC cells.The authors conclude that TM9SF1 may be an oncogene in bladder cancer pathogenesis.
基金Supported by 2020 Guangxi Zhuang Autonomous Region Health Care Commission Self-Financing Research Projects,No.Z202000962023 Guangxi University Young and Middle-Aged Teachers’Basic Research Ability Improvement Project,No.2023KY0091+1 种基金National Natural Science Foundation of China,No.82260241the Natural Science Foundation of Guangxi Province,No.2015GXNSFAA139171 and No.2020GXNSFAA259053.
文摘BACKGROUND Alzheimer’s disease(AD)is a neurodegenerative condition characterized by oxidative stress and neuroinflammation.Tanshinone ⅡA(Tan-ⅡA),a bioactive compound isolated from Salvia miltiorrhiza plants,has shown potential neuroprotective effects;however,the mechanisms underlying such a function remain unclear.AIM To investigate potential Tan-ⅡA neuroprotective effects in AD and to elucidate their underlying mechanisms.METHODS Hematoxylin and eosin staining was utilized to analyze structural brain tissue morphology.To assess changes in oxidative stress and neuroinflammation,we performed enzyme-linked immunosorbent assay and western blotting.Additionally,the effect of Tan-ⅡA on AD cell models was evaluated in vitro using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.Genetic changes related to the long non-coding RNA(lncRNA)nuclear-enriched abundant transcript 1(NEAT1)/microRNA(miRNA,miR)-291a-3p/member RAS oncogene family Rab22a axis were assessed through reverse transcription quantitative polymerase chain reaction.RESULTS In vivo,Tan-ⅡA treatment improved neuronal morphology and attenuated oxidative stress and neuroinflammation in the brain tissue of AD mice.In vitro experiments showed that Tan-ⅡA dose-dependently ameliorated the amyloid-beta 1-42-induced reduction of neural stem cell viability,apoptosis,oxidative stress,and neuroinflammation.In this process,the lncRNA NEAT1-a potential therapeutic target-is highly expressed in AD mice and downregulated via Tan-ⅡA treatment.Mechanistically,NEAT1 promotes the transcription and translation of Rab22a via miR-291a-3p,which activates nuclear factor kappa-B(NF-κB)signaling,leading to activation of the pro-apoptotic B-cell lymphoma 2-associated X protein and inhibition of the anti-apoptotic B-cell lymphoma 2 protein,which exacerbates AD.Tan-ⅡA intervention effectively blocked this process by inhibiting the NEAT1/miR-291a-3p/Rab22a axis and NF-κB signaling.CONCLUSION This study demonstrates that Tan-ⅡA exerts neuroprotective effects in AD by modulating the NEAT1/miR-291a-3p/Rab22a/NF-κB signaling pathway,serving as a foundation for the development of innovative approaches for AD therapy.
基金National Natural Science Foundation of China under Nos.50808107,51178250 and 51261120377
文摘A new type of beam-to-column connection for steel moment flames, designated as a "self-centering connection," is studied. In this connection, bolted top-and-seat angles, and post-tensioned (PT) high-strength steel strands running along the beam are used. The PT strands tie the beam flanges on the column flange to resist moment and provide self-centering force. After an earthquake, the connections have zero deformation, and can be restored to their original status by simply replacing the angles. Four full-scale connections were tested under cyclic loading. The strength, energy-dissipation capacity, hysteresis curve, as well as angles and PT strands behavior of the connections are investigated. A general FEM analysis program called ABAQUS 6.9 is adopted to model the four test specimens. The numerical and test results match very well. Both the test and analysis results suggest that: (1) the columns and beams remain elastic while the angles sustain plastic deformations for energy dissipation when the rotation of the beam related to the column equals 0.05 tad, (2) the energy dissipation capacity is enhanced when the thickness of the angle is increased, and (3) the number of PT strands has a significant influence on the behavior of the connections, whereas the distance between the strands is not as important to the performance of the connection.
基金National Natural Science Foundation of China(NSFC)under Grant Nos.51638012 and 51578401
文摘The seismic performance of a self-centering precast reinforced concrete (RC) frame with shear walls was investigated in this paper. The lateral force resistance was provided by self-centering precast RC shear walls (SPCW), which utilize a combination ofunbonded prestressed post-tensioned (PT) tendons and mild steel reinforcing bars for flexural resistance across base joints. The structures concentrated deformations at the bottom joints and the unbonded PT tendons provided the self-centering restoring force. A 1/3-scale model of a five-story self-centering RC frame with shear walls was designed and tested on a shake-table under a series of bi-directional earthquake excitations with increasing intensity. The acceleration response, roof displacement, inter-story drifts, residual drifts, shear force ratios, hysteresis curves, and local behaviour of the test specimen were analysed and evaluated. The results demonstrated that seismic performance of the test specimen was satisfactory in the plane of the shear wall; however, the structure sustained inter-story drift levels up to 2.45%. Negligible residual drifts were recorded after all applied earthquake excitations. Based on the shake-table test results, it is feasible to apply and popularize a self-centering precast RC frame with shear walls as a structural system in seismic regions.
基金Univeristy of Maryland,Start-up Grant to the First Author
文摘This paper presents the results of a parametric study of self-centering seismic retrofit schemes for reinforced concrete (RC) frame buildings. The self-centering retrofit system features flag-shaped hysteresis and minimal residual deformation. For comparison purpose,an alternate seismic retrofit scheme that uses a bilinear-hysteresis retrofit system such as buckling-restrained braces (BRB) is also considered in this paper. The parametric study was carried out in a single-degree-of-freedom (SDOF) system framework since a multi-story building structure may be idealized as an equivalent SDOF system and investigation of the performance of this equivalent SDOF system can provide insight into the seismic response of the multi-story building. A peak-oriented hysteresis model which can consider the strength and stiffness degradation is used to describe the hysteretic behavior of RC structures. The parametric study involves two key parameters -the strength ratio and elastic stiffness ratio between the seismic retrofit system and the original RC frame. An ensemble of 172 earthquake ground motion records scaled to the design basis earthquake in California with a probability of exceedance of 10% in 50 years was constructed for the simulation-based parametric study. The effectiveness of the two seismic retrofit schemes considered in this study is evaluated in terms of peak displacement ratio,peak acceleration ratio,energy dissipation demand ratio and residual displacement ratio between the SDOF systems with and without retrofit. It is found from this parametric study that RC structures retrofitted with the self-centering retrofit scheme (SCRS) can achieve a seismic performance level comparable to the bilinear-hysteresis retrofit scheme (BHRS) in terms of peak displacement and energy dissipation demand ratio while having negligible residual displacement after earthquake.
基金supported by Youth Technological Phosphor Project of Shanghai City (No.04QMX1474).
文摘Firstly, in view of the respective defects of existing self-centering devices for vehicle suspension height, the design scheme of the proposed mechanical self-centering device for suspension height is described. Taking the rear suspension of a certain light bus as a research example, the structures and parameters of the novel device are designed and ascertained. Then, the road excitation models, the performance evaluation indexes and the half-vehicle model are built, the simulation outputs of time and frequency domain are obtained with the road excitations of random and pulse by using MATLAB/Simulink software. So the main characteristics of the self-centering suspension are presented preliminarily. Finally, a multi-objective parameter design optimization model for the self-centering device is built by weighted sum approach, and optimal solution is obtained by adopting complex approach. The relevant choosing-type parameters for self-centering device components are deduced by using discrete variable optimal method, and the optimal results are verified and analyzed. So the performance potentials of the self-centering device are exerted fully in condition of ensuring overall suspension performances.
基金National Natural Science Foundation of China Under Grant No. 51078075a grant from Southeast University (No. 3205000502)the financial support from the State Key Lab of Subtropical Building Science, South China University of Technology under Grant No. 2010KB05
文摘A new type of steel moment resisting frame with bottom flange friction devices (BFFDs) has been developed to provide self-centering capacity and energy dissipation, and to reduce permanent deformations under earthquakes. This paper presents a numerical simulation of self-centering beam-column connections with BFFDs, in which the gap opening/closing at the beam-column interfaces is simulated by using pairs of zero-length elements with compression-only material properties, and the energy dissipation due to friction is simulated by using truss elements with specified hysteretic behavior. In particular, the effect of the friction bolt bearing against the slotted plate in the BFFDs was modeled, so that the increase in lateral force and the loss of friction force due to the bolt bearing could be taken into account. Parallel elastic-perfectly plastic gap (ElasticPPGap) materials in the Open System for Earthquake Engineering Simulation (OpenSees) were used with predefined gaps to specify the sequence that each bolt went into the bearing and the corresponding increase in bending stiffness. The MinMax material in OpenSees is used to specify the minimum and maximum values of strains of the ElasticPPGap materials. To consider the loss of friction force due to bok bearing, a number of parallel hysteretic materials were used, and the failure of these materials in sequence simulated the gradual loss of friction force. Analysis results obtained by using the proposed numerical model are discussed and compared with the test results under cyclic loadings and the seismic loading, respectively.
基金Key Project of the Key Laboratory of Earthquake Engineering and Engineering Vibration,China Earthquake Administration under Grant No.2019EEEVL0304National Natural Science Foundation of China(NSFC)under Grant No.51678543。
文摘The seismic performance of a five-story,four-bay,self-centering precast reinforced concrete frame(SC-RCF),which was redesigned using the direct displacement-based design method,was analytically investigated.The analytical model of the overall structure was developed in OpenSees.The multi-spring contact element was adopted to simulate gap open-close behavior at connection interfaces.The limit states of external mild steel dampers and unbonded post-tensioning strands were considered.Static pushover analyses were performed up to the roof drift of 10%.The nonlinear dynamic responses under four groups of ground motions(with different fault distances and site conditions)at six hazard levels(from the service to the very rare earthquake(VRE))were compared.Incremental dynamic analyses were implemented to quantify the structural collapse risk.The results showed that the structural responses of SC-RCF were satisfactory under all levels of earthquakes.The collapse safety of the structure under earthquakes up to VRE1 was adequate,while the structure would collapse to a large extent under VRE2 and VRE3.
文摘Self-centering earthquake-resistant structures have received increased attention due to their ability to reduce post-earthquake residual deformations and,thus,repair time and cost.This stimulated the development of recentering shape memory alloy(SMA)dampers that use superelastic nitinol wires to dissipate energy and self-center the structure.However,there are still a few case studies applications on full-scale RC buildings in the literature.Moreover,general guidelines or even simplified approaches for the practical design of SMA damped braces are still lacking.This paper focuses on evaluating the effect of using self-centering shape memory alloy dampers for buckling-restrained braces applied for the seismic retrofit of a complex RC building structure.A design method originally proposed for elastoplastic dampers was implemented to size the SMA dampers to be placed on selected spans and stories of a building.The effectiveness of the design procedure was demonstrated by nonlinear time-history analyses under different sets of earthquake strong ground motions.The analysis results show that the recentering shape memory alloy bracing system is effective in limiting the maximum transient inter-story drifts and reducing the residual inter-story drifts after strong seismic events,due to its excellent recentering behavior together with its not negligible energy dissipation capacity.
基金supported by the National Natural Science Foundation of China(Grant No.51879124)。
文摘Tubular members subject to combined pitting corrosion and crack damage were numerically studied to clarify the reduction of ultimate strength and failure behavior,based on numerical models validated against available experi-ments.The effects of length,location and inclined angle of a crack under combined damage were studied to disclose the mechanism of interaction between the crack and corrosion pits.The methods,named as linear superposition directly accumulating the effects of solo crack and solo pitting damage,as well as crack projection transferring an inclined crack to a transverse one,were discussed and verified in the view of assessing ultimate strength of tubular members with combined damage.It was shown that the former is practical but complex while the next always over-estimates the residual strength.Besides,the location and inclined angle of a crack have a subtle effect on the reduction of ultimate strength under combined damage,especially at higher level of pitting damage,due to the synergistic effect between corrosion pits and cracks.Such effect can lead to early occurrence of plasticity and local buckling by inducing stress interaction between crack tips and pits,and causing more significant strength reduction compared with a solo type of damage.A practical method was proposed to determine the loss ratio of cross-sectional area on the equivalent weakest section of a damaged member.Based on the loss ratio,a formula was presented to predict the ultimate strength of damaged members with combined damage,showing good applicability.
文摘To explore the genesis of the laminated calcite veins developed in the black shale of Chang 73 submember of the Ordos Basin,the petrology,microstructure and geochemistry of calcite veins are studied using thin sections,fluid inclusions,trace elements and isotopic geochemistry.The source,the time of formation,the mechanism of formation,and the dynamic background of the veins are discussed.The veins are mostly made up of calcite,mixed with lenticular or spindle-shape solid wall rock inclusions.Three structures are identified in the calcite minerals:fibrous,rhombic cleavage,and wedge-like structure.Trace elements and isotopes of carbon and oxygen confirm that the calcite veins were formed from a high density hydrothermal fluid.It is assumed that calcite veins formed prior to wall rock consolidation during the formation of the Qinling Orogenic Belt in the Middle and Late Triassic.The results show that the sedimentary sources of Chang 73 submember were influenced by hydrothermal materials besides terrigenous detritus.The fibrous calcite is different from the fibrous calcite reported in the morphology and mechanism of formation.In this way,the research complements and improves the morphology and the mechanism of formation of fibrous calcite.
基金Supported by the National Major Research and Development Project(2020YFA0710504,2022YFF0801204)PetroChina Science and Technology Major Project(2019E-26)。
文摘According to the theory of sequence stratigraphy based on continental transgressive-regressive(T-R)cycles,a 500 m continuous core taken from the second member of Kongdian Formation(Kong 2 Member)of Paleogene in Well G108-8 in the Cangdong Sag,Bohai Bay Basin,was tested and analyzed to clarify the high-frequency cycles of deep-water fine-grained sedimentary rocks in lacustrine basins.A logging vectorgraph in red pattern was plotted,and then a sequence stratigraphic framework with five-order high-frequency cycles was formed for the fine-grained sedimentary rocks in the Kong 2 Member.The high-frequency cycles of fine-grained sedimentary rocks were characterized by using different methods and at different scales.It is found that the fifth-order T cycles record a high content of terrigenous clastic minerals,a low paleosalinity,a relatively humid paleoclimate and a high density of laminae,while the fifth-order R cycles display a high content of carbonate minerals,a high paleosalinity,a dry paleoclimate and a low density of laminae.The changes in high-frequency cycles controlled the abundance and type of organic matter.The T cycles exhibit relatively high TOC and abundant endogenous organic matters in water in addition to terrigenous organic matters,implying a high primary productivity of lake for the generation and enrichment of shale oil.