During the last four decades, reinforced-concrete structure failures have been happening widely for many reasons, such as increased service loads, war accidents, fire, and durability problems. The economic losses due ...During the last four decades, reinforced-concrete structure failures have been happening widely for many reasons, such as increased service loads, war accidents, fire, and durability problems. The economic losses due to those failures are very high. An expert system is an interactive computer-based decision tool that uses both facts and heuristics to solve difficult problems based on knowledge acquired from experts. To realize these requirements, a logic programming visual basic language is used together with visual diagnosis. The expert system, Diagnosis of Fire-Caused Damages to Reinforced-Concrete Tunnel Lining (DFCDRCTL) was developed in this work for diagnosing the annual damages caused by fire. The program is used as an alternative of a human expert to make annual technical decisions in diagnosing fire damages at the second reinforced-concrete tunnel lining segment. It is concluded that the proposed DFCDRCTL expert system is easy to use, and is fast and helpful for engineers.展开更多
With the expansion of international terrorism and the potential threat of attacks against civil infrastructure,the dynamic response and failure modes of underground tunnels under explosive loads have become a prominen...With the expansion of international terrorism and the potential threat of attacks against civil infrastructure,the dynamic response and failure modes of underground tunnels under explosive loads have become a prominent research topic.The high cost and inherent danger associated with explosion experiments have limited current research on tunnel internal explosions,particularly in the context of scaled model tests of shield tunnels.This study presents a series of scaled model tests under 1g-condition simulating internal blast events within a shield tunnel based on the prototype of the Shantou Bay Tunnel,considering the influences of surrounding stratum and equivalent explosive yield.Three different TNT explosive yields are considered in the model tests,namely 0.2,0.4,and 1.0 kg.The model tests focus on the damage behavior and collapse modes of the shield tunnel lining under internal explosive loads.The model tests reveal that the shield tunnel is prone to damage at the joints of the tunnel crown and shoulder when subjected to internal explosive loads,with the upper half of the tunnel lining experiencing segment collapse,while the lower half remains largely undamaged.As the TNT equivalent increases,the damage area at the tunnel joints expands,and the number of segment failures in the upper half of the tunnel rises,transitioning from a damaged state to a collapsed state.The influence of“stratum-structure”interaction is investigated by comparing two models,one with overburden soil and the other positioned at the ground surface.The model tests reveal that the presence of soil pressure and confinement can significantly enhance the tunnel resistance to internal blast loads.Based on the observation of the model tests,five different damage modes of segment joints under internal explosion are proposed in this study.展开更多
The rotational seismic motions are estimated from one station records of the 1999 Jiji （Chi-Chi）, Taiwan, earthquake based on the theory of elastic plane wave propagation. The time-frequency response spectrum （TFRS...The rotational seismic motions are estimated from one station records of the 1999 Jiji （Chi-Chi）, Taiwan, earthquake based on the theory of elastic plane wave propagation. The time-frequency response spectrum （TFRS） of the rotational motions is calculated and its characteristics are analyzed, then the TFRS is applied to analyze the damage mechanism of one twelve-storey frame concrete structure. The results show that one of the ground motion components can not reflect the characteristics of the seismic motions completely; the characteristics of each component, especially rotational motions, need to be studied. The damage line of the structure and TFRS of ground motion are important for seismic design, only the TFRS of input seismic wave is suitable, the structure design is reliable.展开更多
Colitis is a chronic bowel disease characterized by damage to the lining of the large intestine,with its precise underlying causes remaining incompletely understood.In this study,we provide evidence that circular RNA ...Colitis is a chronic bowel disease characterized by damage to the lining of the large intestine,with its precise underlying causes remaining incompletely understood.In this study,we provide evidence that circular RNA circNlgn plays a pivotal role in promoting the development of colitis.Colitis patients produce significant higher levels of circNign.Transgenic mice expressing circNlgn exhibit heightened susceptibility to colitis development and progression,primarily attributed to the presence of the protein isoform Nlgn173 encoded by circNign.Nlgn173 undergoes translocation into cellnuclei,where it interacts with actin,impeding the binding of actin-related protein 2 and 3(Arp2/3)complex to actin molecules.Consequently,this leads to a reduction in actin polymerization.Mechanistically,Nlgn173 enhances tyrosine-53 phosphorylation of nuclear actin,diminishing its capacity to interact with the Arp2/3 complex and causing a decrease in filamentous actin levels.These alterations in actin dynamics result in inhibited cell cycle progression,increased apoptosis,and decreased proliferation of colonic epithelial cells,thereby exacerbating colitis development and progression.In contrast,the silencing of circNign or the targeted inhibition of Nlgn173 translation and nuclear translocation leads to the promotion of nuclear actin polymerization,enhanced cell survival,and reduced apoptosis and ultimately improves the outcome of colitis in vivo.Interestingly,nuclear actin polymerization is highly related with expression of PIAS3,which modulates signal transducer and activator of transcription 3 and NF-kB activity in colitis.Strategies such as circNlgn knockdown and targeting nuclear actin polymerization of the colonic epithelium may explore a novel avenue for acute ulcerativecolitisclinical intervention.展开更多
基金Funded by the National Natural Science Foundation of China under Grant No. 51278427the Program for New Century Excellent Talents in Universities under Grant No. 10-0667+1 种基金the National Natural Science Foundation of High Iron Mutual Funds (No. U1134208)the Fundamental Research Funds for the Central Universities (No. SWJTU11ZT33)
文摘During the last four decades, reinforced-concrete structure failures have been happening widely for many reasons, such as increased service loads, war accidents, fire, and durability problems. The economic losses due to those failures are very high. An expert system is an interactive computer-based decision tool that uses both facts and heuristics to solve difficult problems based on knowledge acquired from experts. To realize these requirements, a logic programming visual basic language is used together with visual diagnosis. The expert system, Diagnosis of Fire-Caused Damages to Reinforced-Concrete Tunnel Lining (DFCDRCTL) was developed in this work for diagnosing the annual damages caused by fire. The program is used as an alternative of a human expert to make annual technical decisions in diagnosing fire damages at the second reinforced-concrete tunnel lining segment. It is concluded that the proposed DFCDRCTL expert system is easy to use, and is fast and helpful for engineers.
基金funding from the National Natural Foundation of China(Grant Nos.52178385 and 52020105002).
文摘With the expansion of international terrorism and the potential threat of attacks against civil infrastructure,the dynamic response and failure modes of underground tunnels under explosive loads have become a prominent research topic.The high cost and inherent danger associated with explosion experiments have limited current research on tunnel internal explosions,particularly in the context of scaled model tests of shield tunnels.This study presents a series of scaled model tests under 1g-condition simulating internal blast events within a shield tunnel based on the prototype of the Shantou Bay Tunnel,considering the influences of surrounding stratum and equivalent explosive yield.Three different TNT explosive yields are considered in the model tests,namely 0.2,0.4,and 1.0 kg.The model tests focus on the damage behavior and collapse modes of the shield tunnel lining under internal explosive loads.The model tests reveal that the shield tunnel is prone to damage at the joints of the tunnel crown and shoulder when subjected to internal explosive loads,with the upper half of the tunnel lining experiencing segment collapse,while the lower half remains largely undamaged.As the TNT equivalent increases,the damage area at the tunnel joints expands,and the number of segment failures in the upper half of the tunnel rises,transitioning from a damaged state to a collapsed state.The influence of“stratum-structure”interaction is investigated by comparing two models,one with overburden soil and the other positioned at the ground surface.The model tests reveal that the presence of soil pressure and confinement can significantly enhance the tunnel resistance to internal blast loads.Based on the observation of the model tests,five different damage modes of segment joints under internal explosion are proposed in this study.
基金funded by the National Natural Science Foundation of China under grant No.50578125
文摘The rotational seismic motions are estimated from one station records of the 1999 Jiji （Chi-Chi）, Taiwan, earthquake based on the theory of elastic plane wave propagation. The time-frequency response spectrum （TFRS） of the rotational motions is calculated and its characteristics are analyzed, then the TFRS is applied to analyze the damage mechanism of one twelve-storey frame concrete structure. The results show that one of the ground motion components can not reflect the characteristics of the seismic motions completely; the characteristics of each component, especially rotational motions, need to be studied. The damage line of the structure and TFRS of ground motion are important for seismic design, only the TFRS of input seismic wave is suitable, the structure design is reliable.
基金supported by the grants from Canadian Institutes of Health Research(PJT-155962 and PJT-166107)to B.B.Y.
文摘Colitis is a chronic bowel disease characterized by damage to the lining of the large intestine,with its precise underlying causes remaining incompletely understood.In this study,we provide evidence that circular RNA circNlgn plays a pivotal role in promoting the development of colitis.Colitis patients produce significant higher levels of circNign.Transgenic mice expressing circNlgn exhibit heightened susceptibility to colitis development and progression,primarily attributed to the presence of the protein isoform Nlgn173 encoded by circNign.Nlgn173 undergoes translocation into cellnuclei,where it interacts with actin,impeding the binding of actin-related protein 2 and 3(Arp2/3)complex to actin molecules.Consequently,this leads to a reduction in actin polymerization.Mechanistically,Nlgn173 enhances tyrosine-53 phosphorylation of nuclear actin,diminishing its capacity to interact with the Arp2/3 complex and causing a decrease in filamentous actin levels.These alterations in actin dynamics result in inhibited cell cycle progression,increased apoptosis,and decreased proliferation of colonic epithelial cells,thereby exacerbating colitis development and progression.In contrast,the silencing of circNign or the targeted inhibition of Nlgn173 translation and nuclear translocation leads to the promotion of nuclear actin polymerization,enhanced cell survival,and reduced apoptosis and ultimately improves the outcome of colitis in vivo.Interestingly,nuclear actin polymerization is highly related with expression of PIAS3,which modulates signal transducer and activator of transcription 3 and NF-kB activity in colitis.Strategies such as circNlgn knockdown and targeting nuclear actin polymerization of the colonic epithelium may explore a novel avenue for acute ulcerativecolitisclinical intervention.
