The dynamic responses of the Tsing Ma suspension bridge and the running behaviors of trains on the bridge under turbulent wind actions are analyzed by a three-dimensional wind-train-bridge interaction model. This mode...The dynamic responses of the Tsing Ma suspension bridge and the running behaviors of trains on the bridge under turbulent wind actions are analyzed by a three-dimensional wind-train-bridge interaction model. This model consists of a spatial finite element bridge model, a train model composed of eight 4-axle identical coaches of 27 degrees-of-freedom, and a turbulent wind model. The fluctuating wind forces, including the buffeting forces and the self-excited forces, act on the bridge only, since the train runs inside the bridge deck. The dynamic responses of the bridge are calculated and some results are compared with data measured from Typhoon York. The runnability of the train passing through the Tsing Ma suspension bridge at different speeds is researched under turbulent winds with different wind velocities. Then, the threshold curve of wind velocity for ensuring the running safety of the train in the bridge deck is proposed, from which the allowable train speed at different wind velocities can be determined. The numerical results show that rail traffic on the Tsing Ma suspension bridge should be closed as the mean wind velocity reaches 30 m/s.展开更多
In this paper, an FEM （Finite Element Method） model is established for the main span of the bridge, with the main box arch and suspender members modeled by beam elements, truss members by truss elements, and the ort...In this paper, an FEM （Finite Element Method） model is established for the main span of the bridge, with the main box arch and suspender members modeled by beam elements, truss members by truss elements, and the orthotropic steel deck by plate elements. The natural frequencies and mode shapes are acquired by the eigen-parameter analysis. By input of a typical earthquake excitation to the bridge system, the dynamic responses of the bridge, including the displacement and accelerations of the main joints of the structure, and the seismic forces and stresses of the key members, are calculated by the structural analysis program, based on which the main laws of the seismic responses of the bridge are summarized, and the safety of the structure is evaluated.展开更多
The traffic-induced vibrations of the new CCTV Headquarters building are studied stages. In the first stage when the through experiments in two 30th floor of the northwest tower and the 38th floor of the southeast tow...The traffic-induced vibrations of the new CCTV Headquarters building are studied stages. In the first stage when the through experiments in two 30th floor of the northwest tower and the 38th floor of the southeast tower were finished, the traffic flows on the roads surrounding the building were investigated, and 27 setups of accelerations were measured at the roadside, on the pile cap and on the 9th floor. In the second stage when the whole steel structure was completed, l 5 setups of accelerations were measured at the roadside, on the pile cap and on the 37th and the 48th floors. The accelerations of the building under different traffic flows, in different positions are analyzed in both time domain and frequency domain. The damping ratios are estimated by the upgraded half-power bandwidth method.展开更多
In this paper, a field experiment was carried out to study train-induced environmental vibrations. During the field experiment, velocity responses were measured at different locations of a six-story masonry structure ...In this paper, a field experiment was carried out to study train-induced environmental vibrations. During the field experiment, velocity responses were measured at different locations of a six-story masonry structure near the Beijing- Guangzhou Railway and along a small road adjacent to the building. The results show that the velocity response levels of the environmental ground and the building floors increase with train speed, and attenuate with the distance to the railway track. Heavier freight trains induce greater vibrations than lighter passenger trains. In the multi-story building, the lateral velocity levels increase monotonically with floor elevation, while the vertical ones increase with floor elevation in a fluctuating manner. The indoor floor vibrations are much lower than the outdoor ground vibrations. The lateral vibration of the building along the direction of weak structural stiffness is greater than along the direction with stronger stiffness. A larger room produces greater floor vibrations than the staircase at the same elevation, and the vibration at the center of a room is greater than at its corner. The vibrations of the building were compared with the Federal Transportation Railroad Administration （FTA） criteria for acceptable ground-borne vibrations expressed in terms ofrms velocity levels in decibels. The results show that the train-induced building vibrations are serious, and some exceed the allowance given in relevant criterion.展开更多
Antibiotic resistance genes(ARGs)might have great effect on ecological security and human health.Oceans are important reservoirs that receive tremendous amounts of pollutants globally.However,information on the prolif...Antibiotic resistance genes(ARGs)might have great effect on ecological security and human health.Oceans are important reservoirs that receive tremendous amounts of pollutants globally.However,information on the proliferation of ARGs in seawater is still limited.This study performed field sampling to investigate the occurrence and distribution of ARGs in seawater of the South China Sea,which is the deepest and largest sea in China.The results showed that the total absolute abundances of ARGs in seawater samples ranged from 2.1×10^(3)to 2.3×10^(4)copies/mL,with an of 5.0×10^(3)copies/mL and a range of 2.2×10^(3)–1.8×10^(4)copies/mL for those with mobile genetic elements(MGEs).Genes resistant to multidrug,aminoglycoside,tetracycline,and fluoroquinolone antibiotics accounted for 77.3%–88.6%of total ARGs in seawater.Proteobacteria and Cyanobacteria represented 32.1%–56.2%and 30.4%–49.5%of microbial community,respectively.Prochlorococcus_MIT9313 and Clade_la were the prevalent genera in seawater of the South China Sea.Complex co-occurrence relationship existed among ARGs,MGEs,and bacteria.Anthropogenic activities had critical influence on ARGs and MGEs.Hospital wastewater,wastewater treatment plant effluent,sewage,aquaculture tailwater,and runoff were determined as the important sources of ARGs in seawater of the South China Sea based on positive matrix factorization analysis.展开更多
It is difficult for physicians to identify patients with metastatic nasopharyngeal carcinoma(NPC)who are sensitive to local treatment of metastases.Here,we aimed to establish a prognostic model for survival and indivi...It is difficult for physicians to identify patients with metastatic nasopharyngeal carcinoma(NPC)who are sensitive to local treatment of metastases.Here,we aimed to establish a prognostic model for survival and individualize treatments for patients with metastatic NPC.Data were collated from 240 NPC patients diagnosed with metachronous metastasis between 2006 and 2020 who received palliative chemotherapy with or without local treatment.Multivariable Cox regression was implemented to construct a nomogram which had a concordance index of 0.764 when predicting 1-,3-,and 5-year overall survival(OS).We then classified patients according to risk,creating low-and high-risk groups using the nomogram.Differences in OS between the two groups were significant(P<0.001).In the low-risk group,the OS for patients who received local treatment was longer than those without(P=0.009).This novel nomogram shows good performance in classifying patients according to risk and may also be a promising tool for determining who responds best to local treatment.Further validation using external center data is warranted.展开更多
Objective： The aim of the study was to investigate the apoptosis induced by piperlongumine on human breast adenoma MDA-MB-231 cells and the mechanism involved. Methods： Human breast adenoma MDA-MB-231 cells line was...Objective： The aim of the study was to investigate the apoptosis induced by piperlongumine on human breast adenoma MDA-MB-231 cells and the mechanism involved. Methods： Human breast adenoma MDA-MB-231 cells line was cultured in vitro. The inhibitory effect of piperlongumine on the proliferation of human breast adenoma MDA-MB-231 cells was measured by CCK-8 assay. Distribution of cell cycle was analyzed by flow cytometry. The apoptosis rates of MDA-MB- 231 cells were measured using Annexin V/PI staining. The flow cytometry with the probe of DCFH-DA was used to detect the intracellular reactive oxygen species levels. Western blot was used to explore the protein expression of Bcl-2 and Bax. Results： The CCK-8 assay showed that piperlongumine had an inhibiting effect on the proliferation of MDA-MB-231 cells in a concentrationand time-dependent manner. MDA-MB-231 cells were markedly arrested at G0/G1 phase after treatment of piperlongumine. Piperlongumine induced apoptosis of MDA-MB-231 cells obviously. The level of intracellular reactive oxygen species was increased in a dose-dependent manner. The antioxidant N-acetyI-L-cystein inhibited the apoptosis of cells and the level of intracellular reactive oxygen species was also decreased. By Western blot analysis, we found the expression of Bax was up-regulated whereas that of Bcl-2 was down-regulated in a concentration-dependent manner. Conclusion： PiperIongumine possesses a significant function for inhibiting proliferation, arresting cells at G0/G1 phase and inducing apoptosis of MDA-MB-231 cells, which seems to be associated with the increased generation of intracellular reactive oxygen species as well as the down-regulation of Bcl-2 and up-regulation of Bax.展开更多
基金National Natural Science Foundation of China Under Grant No.90715008, 50838006The Fundamental Research Funds for the Central Universities Under Grant No 2009JBM078
文摘The dynamic responses of the Tsing Ma suspension bridge and the running behaviors of trains on the bridge under turbulent wind actions are analyzed by a three-dimensional wind-train-bridge interaction model. This model consists of a spatial finite element bridge model, a train model composed of eight 4-axle identical coaches of 27 degrees-of-freedom, and a turbulent wind model. The fluctuating wind forces, including the buffeting forces and the self-excited forces, act on the bridge only, since the train runs inside the bridge deck. The dynamic responses of the bridge are calculated and some results are compared with data measured from Typhoon York. The runnability of the train passing through the Tsing Ma suspension bridge at different speeds is researched under turbulent winds with different wind velocities. Then, the threshold curve of wind velocity for ensuring the running safety of the train in the bridge deck is proposed, from which the allowable train speed at different wind velocities can be determined. The numerical results show that rail traffic on the Tsing Ma suspension bridge should be closed as the mean wind velocity reaches 30 m/s.
基金Acknowledgments： This study is sponsored by the Natural Science Foundation of China （No. 90715008） and the Flander （Belgium）-China Bilateral Project （No. BIL07/07）.
文摘In this paper, an FEM （Finite Element Method） model is established for the main span of the bridge, with the main box arch and suspender members modeled by beam elements, truss members by truss elements, and the orthotropic steel deck by plate elements. The natural frequencies and mode shapes are acquired by the eigen-parameter analysis. By input of a typical earthquake excitation to the bridge system, the dynamic responses of the bridge, including the displacement and accelerations of the main joints of the structure, and the seismic forces and stresses of the key members, are calculated by the structural analysis program, based on which the main laws of the seismic responses of the bridge are summarized, and the safety of the structure is evaluated.
基金The study is sponsored by the National Natural Science Foundation of China （No. 50538010） and the Flander （Belgium）-China Bilateral Project （,No. BIL 07/07）.
文摘The traffic-induced vibrations of the new CCTV Headquarters building are studied stages. In the first stage when the through experiments in two 30th floor of the northwest tower and the 38th floor of the southeast tower were finished, the traffic flows on the roads surrounding the building were investigated, and 27 setups of accelerations were measured at the roadside, on the pile cap and on the 9th floor. In the second stage when the whole steel structure was completed, l 5 setups of accelerations were measured at the roadside, on the pile cap and on the 37th and the 48th floors. The accelerations of the building under different traffic flows, in different positions are analyzed in both time domain and frequency domain. The damping ratios are estimated by the upgraded half-power bandwidth method.
基金National Natural Science Foundation of China Under Grant No. 50538010Natural Science Foundation of Beijing Under Grant No. 8082021the Flander (Belgium)-China Bilateral Project Under Grant No. BIL07/07
文摘In this paper, a field experiment was carried out to study train-induced environmental vibrations. During the field experiment, velocity responses were measured at different locations of a six-story masonry structure near the Beijing- Guangzhou Railway and along a small road adjacent to the building. The results show that the velocity response levels of the environmental ground and the building floors increase with train speed, and attenuate with the distance to the railway track. Heavier freight trains induce greater vibrations than lighter passenger trains. In the multi-story building, the lateral velocity levels increase monotonically with floor elevation, while the vertical ones increase with floor elevation in a fluctuating manner. The indoor floor vibrations are much lower than the outdoor ground vibrations. The lateral vibration of the building along the direction of weak structural stiffness is greater than along the direction with stronger stiffness. A larger room produces greater floor vibrations than the staircase at the same elevation, and the vibration at the center of a room is greater than at its corner. The vibrations of the building were compared with the Federal Transportation Railroad Administration （FTA） criteria for acceptable ground-borne vibrations expressed in terms ofrms velocity levels in decibels. The results show that the train-induced building vibrations are serious, and some exceed the allowance given in relevant criterion.
基金supported by the National Natural Science Foundation of China(No.42276155)the Taishan Scholars Program,Shandong Provincial Natural Science Foundation(No.ZR2020QD131)+1 种基金the Research Program of CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation(No.1189010002)the Key R&D Program of Shandong Province,China(No.2022CXPT019).
文摘Antibiotic resistance genes(ARGs)might have great effect on ecological security and human health.Oceans are important reservoirs that receive tremendous amounts of pollutants globally.However,information on the proliferation of ARGs in seawater is still limited.This study performed field sampling to investigate the occurrence and distribution of ARGs in seawater of the South China Sea,which is the deepest and largest sea in China.The results showed that the total absolute abundances of ARGs in seawater samples ranged from 2.1×10^(3)to 2.3×10^(4)copies/mL,with an of 5.0×10^(3)copies/mL and a range of 2.2×10^(3)–1.8×10^(4)copies/mL for those with mobile genetic elements(MGEs).Genes resistant to multidrug,aminoglycoside,tetracycline,and fluoroquinolone antibiotics accounted for 77.3%–88.6%of total ARGs in seawater.Proteobacteria and Cyanobacteria represented 32.1%–56.2%and 30.4%–49.5%of microbial community,respectively.Prochlorococcus_MIT9313 and Clade_la were the prevalent genera in seawater of the South China Sea.Complex co-occurrence relationship existed among ARGs,MGEs,and bacteria.Anthropogenic activities had critical influence on ARGs and MGEs.Hospital wastewater,wastewater treatment plant effluent,sewage,aquaculture tailwater,and runoff were determined as the important sources of ARGs in seawater of the South China Sea based on positive matrix factorization analysis.
基金supported by the National Natural Science Foundation of China(Grant No.81872192)China International Medical Foundation(Grant No.Z-2014-06-19392).
文摘It is difficult for physicians to identify patients with metastatic nasopharyngeal carcinoma(NPC)who are sensitive to local treatment of metastases.Here,we aimed to establish a prognostic model for survival and individualize treatments for patients with metastatic NPC.Data were collated from 240 NPC patients diagnosed with metachronous metastasis between 2006 and 2020 who received palliative chemotherapy with or without local treatment.Multivariable Cox regression was implemented to construct a nomogram which had a concordance index of 0.764 when predicting 1-,3-,and 5-year overall survival(OS).We then classified patients according to risk,creating low-and high-risk groups using the nomogram.Differences in OS between the two groups were significant(P<0.001).In the low-risk group,the OS for patients who received local treatment was longer than those without(P=0.009).This novel nomogram shows good performance in classifying patients according to risk and may also be a promising tool for determining who responds best to local treatment.Further validation using external center data is warranted.
基金Supported by grants from the Priority Academic Program Development of Jiangsu Higher Education Institutions (No. JX10231801)the Innovative Medical Team and Leading Talent of Jiangsu Province (No. LJ201123)
文摘Objective： The aim of the study was to investigate the apoptosis induced by piperlongumine on human breast adenoma MDA-MB-231 cells and the mechanism involved. Methods： Human breast adenoma MDA-MB-231 cells line was cultured in vitro. The inhibitory effect of piperlongumine on the proliferation of human breast adenoma MDA-MB-231 cells was measured by CCK-8 assay. Distribution of cell cycle was analyzed by flow cytometry. The apoptosis rates of MDA-MB- 231 cells were measured using Annexin V/PI staining. The flow cytometry with the probe of DCFH-DA was used to detect the intracellular reactive oxygen species levels. Western blot was used to explore the protein expression of Bcl-2 and Bax. Results： The CCK-8 assay showed that piperlongumine had an inhibiting effect on the proliferation of MDA-MB-231 cells in a concentrationand time-dependent manner. MDA-MB-231 cells were markedly arrested at G0/G1 phase after treatment of piperlongumine. Piperlongumine induced apoptosis of MDA-MB-231 cells obviously. The level of intracellular reactive oxygen species was increased in a dose-dependent manner. The antioxidant N-acetyI-L-cystein inhibited the apoptosis of cells and the level of intracellular reactive oxygen species was also decreased. By Western blot analysis, we found the expression of Bax was up-regulated whereas that of Bcl-2 was down-regulated in a concentration-dependent manner. Conclusion： PiperIongumine possesses a significant function for inhibiting proliferation, arresting cells at G0/G1 phase and inducing apoptosis of MDA-MB-231 cells, which seems to be associated with the increased generation of intracellular reactive oxygen species as well as the down-regulation of Bcl-2 and up-regulation of Bax.
