Time series measurements were conducted on suspended sediment and current velocity from neap tide to spring tide in the South Branch of the upper Changjiang Estuary in the summer of 2011. Strong flood-ebb asymmetry in...Time series measurements were conducted on suspended sediment and current velocity from neap tide to spring tide in the South Branch of the upper Changjiang Estuary in the summer of 2011. Strong flood-ebb asymmetry in the current velocity was observed in the South Branch as a result of high river runoff and tide deformation, in which the magnitude and duration of ebb currents were significantly greater than those of flood currents. The suspended sediment concentration（SSC） and suspended median grain size also exhibited remarkable flood-ebb variation; these variables were considerably larger during the ebb than during the flood and increased from neap to spring tide. Affected by the strong asymmetry in the current velocity and SSC between the flood and ebb,suspended sediment flux during the ebb was notably larger than during the flood, and a seaward tidal net flux was observed in each tidal cycle. The balance of sediment flux illustrates that the seaward sediment transport was dominated by river flow and tidal trapping and the landward sediment transport was dominated by the Stokes drift and the shear effect. Notable resuspension occurred during the spring and moderate tides. The critical velocity for the resuspension of bed sediments was estimated based on the correlation between current velocity with SSC and suspended median grain size. The results show that the critical velocity was approximately 40 cm/s during the flood phases and approximately 80 cm/s during the ebb phases because the surficial flood bed sediments located in the lower reach are much finer than the surficial ebb bed sediments located in the upper reach. The flood-ebb variation in the critical erosion velocity has significant effect on the intratidal variation of SSC and sediment transport process, and it is a common phenomenon in many estuaries of the world due to the complicated spatial distribution of bed sediments.展开更多
Nanxiaohong and Nangang main south channel are chosen as the typical flood and ebb channels. Hydrodynamics analysis based on field hydrological and sediment data is conducted with Gao-Collins model to analyse sediment...Nanxiaohong and Nangang main south channel are chosen as the typical flood and ebb channels. Hydrodynamics analysis based on field hydrological and sediment data is conducted with Gao-Collins model to analyse sediment transport trends. Also, the grain size distribution analysis of the bottom sediment sampled in Sep. 2001 is used as the base of the analysis. The result shows that the sediment in Nanxiaohong is from the rive mouth area. The sediment transports upwards with the flood flow which is stronger than the ebb flow, i.e., in the direction of SE-WN. The sediment in main south channel comes from upward. They transport downwards with the ebb flow, which is stronger than the flood flow, i.e., in the direction of WN-SE. The directions, sources and mechanism of sediment transport are identified according to comprehensive analyses of the observed data on hydrodynamics and sediment.展开更多
OBJECTIVE To investigate the influence of O-(4-ethoxyl-butyl)- berbamine(EBB)on the expression of cyclin B1 and cdc2-p34 in the human drug-resistant breast cancer MCF-7/ADR cell line. METHODS The MTT assay was used to...OBJECTIVE To investigate the influence of O-(4-ethoxyl-butyl)- berbamine(EBB)on the expression of cyclin B1 and cdc2-p34 in the human drug-resistant breast cancer MCF-7/ADR cell line. METHODS The MTT assay was used to assess the cytotoxicity of EBB.Different levels of EBB were added to different cell lines at series of time points solely or combined with doxorubicin(DOX) to detect the effect on the expression of cyclinB1 and cdc2-p34 by Western blots.cdc2-p34 tyrosine phosphorylation was detected by immunoprecipitation.In addition,apoptosis and cytoplastic Ca 2+ concentrations were systematically examined by laser scanning confocal microscopy(LSCM). RESULTS EBB showed little inhibitory activity on human umbilical vein endothelial cells(ECV304),whereas EBB inhibited cell growth(IC50 range,4.55~15.74μmol/L)in a variety of sensitive and drug-resistance cell lines.EBB also down-regulated the expression of cyclin B1 and cdc2-p34 in a concentration and time dependent manner,which was an important reason for the G2/M phase arrest.EBB was shown to induce apoptosis of MCF-7/ADR cells while increasing the level of cytoplastic Ca 2+ . CONCLUSION The low cytotoxicity of EBB suggests it may be useful as a rational reversal agent.The effect of EBB on cell cycle arrest and related proteins,apoptosis,and cytoplastic Ca 2+ concentration may be involved in reversing multidrug resistance.展开更多
OBJECTIVE: To evaluate the anti-hepatoma effect of Calmodulin antagonist 0 - 4-ethoxyl-butyl-Berbamine (EBB), one of the berbamine derivatives. METHODS: Monotetrazolium (MTT) method was used to analyze the effect of E...OBJECTIVE: To evaluate the anti-hepatoma effect of Calmodulin antagonist 0 - 4-ethoxyl-butyl-Berbamine (EBB), one of the berbamine derivatives. METHODS: Monotetrazolium (MTT) method was used to analyze the effect of EBB on the proliferation and growth inhibition effect. Of a hepatoma cell line in vitro. A mouse hepatoma model was induced by injection of hepatoma cells (H22) in the abdominal cavity. The effect of EBB on survival at different concentrations as well as in combination with 5-FU were investigated in vivo. Flow cytometry analysis, dot blot hybridization, western blot, immunochemistry, enzyme-linked lectin assay (ELISA), trifluoperazine (TFP) and electron microscopic observation were used to study the effect of EBB on cell cycle process, P53 mRNA and protein levels, calmodulin content and ultrastractural changes of hepatoma cells. RESULTS: EBB exerts a very strong inhibitory effect on human hepatoma cell line 7402 and mouse hepatoma cell line H22 in vitro. The IC(50) value of EBB for the two cell lines are 3.312 microg/ml and 1.167 microg/ml, respectively. The sensitivity of H22 cells to 5-FU can be markedly enhanced: The IC(50) dosage of 5-Fu can be decreased from 0.75 microg/ml down to 0.15 microg/ml, when jointly administered with nontoxic dosages of EBB (IC(10)). In vivo, EBB can prolong the lifespan of mice with ascites H22 to more than three months. 64% of mice survived, while all animals in the control group died by the 18th day. When EBB (5 mg x kg(-1) x d(-1)) is jointly used with 5-FU (25 mg x ml(-1) x d(-1)), 73% of mice with ascites H22 survived, much higher than 27% in the 5-FU treated group. EBB can enhance the anti-hepatoma ability of 5-Fu treatment. EBB mechanism against hepatoma: P53 expression in the EBB treated group is substantially higher than that in the control group. EBB increased the translation of P53. As a calmodulin antagonist, EBB decreases amount of the CaM in hepatoma cells and blocked the hepatoma cell proliferation cycle at the G(2)M phase. Before the G(0)/G(1) phase, a diploid peak and apoptic cells in the treated groups were observed. CONCLUSIONS: The CaM antagonist, EBB, has a strong anti-hepatoma effect and enhances the effect of 5-FU, induces hepatoma cell to apoptosis, promotes the P53 protein expression and decreases the amount of CaM in the cytoplasm. All these results demonstrate that EBB is a new and potentially useful drug against hepatoma and should be researched further.展开更多
基金The National Natural Science Foundation of China under contract Nos 41176069 and 48505350the Major State Basic Research Development Program of China under contract No.2013CB956502
文摘Time series measurements were conducted on suspended sediment and current velocity from neap tide to spring tide in the South Branch of the upper Changjiang Estuary in the summer of 2011. Strong flood-ebb asymmetry in the current velocity was observed in the South Branch as a result of high river runoff and tide deformation, in which the magnitude and duration of ebb currents were significantly greater than those of flood currents. The suspended sediment concentration（SSC） and suspended median grain size also exhibited remarkable flood-ebb variation; these variables were considerably larger during the ebb than during the flood and increased from neap to spring tide. Affected by the strong asymmetry in the current velocity and SSC between the flood and ebb,suspended sediment flux during the ebb was notably larger than during the flood, and a seaward tidal net flux was observed in each tidal cycle. The balance of sediment flux illustrates that the seaward sediment transport was dominated by river flow and tidal trapping and the landward sediment transport was dominated by the Stokes drift and the shear effect. Notable resuspension occurred during the spring and moderate tides. The critical velocity for the resuspension of bed sediments was estimated based on the correlation between current velocity with SSC and suspended median grain size. The results show that the critical velocity was approximately 40 cm/s during the flood phases and approximately 80 cm/s during the ebb phases because the surficial flood bed sediments located in the lower reach are much finer than the surficial ebb bed sediments located in the upper reach. The flood-ebb variation in the critical erosion velocity has significant effect on the intratidal variation of SSC and sediment transport process, and it is a common phenomenon in many estuaries of the world due to the complicated spatial distribution of bed sediments.
文摘Nanxiaohong and Nangang main south channel are chosen as the typical flood and ebb channels. Hydrodynamics analysis based on field hydrological and sediment data is conducted with Gao-Collins model to analyse sediment transport trends. Also, the grain size distribution analysis of the bottom sediment sampled in Sep. 2001 is used as the base of the analysis. The result shows that the sediment in Nanxiaohong is from the rive mouth area. The sediment transports upwards with the flood flow which is stronger than the ebb flow, i.e., in the direction of SE-WN. The sediment in main south channel comes from upward. They transport downwards with the ebb flow, which is stronger than the flood flow, i.e., in the direction of WN-SE. The directions, sources and mechanism of sediment transport are identified according to comprehensive analyses of the observed data on hydrodynamics and sediment.
基金This work was supported by grants from the National Nature Science Foundation of China(No.30572203,30570772)the Key Fund of Science of TianJin Municipal Government(No.07JCZDJC04900)
文摘OBJECTIVE To investigate the influence of O-(4-ethoxyl-butyl)- berbamine(EBB)on the expression of cyclin B1 and cdc2-p34 in the human drug-resistant breast cancer MCF-7/ADR cell line. METHODS The MTT assay was used to assess the cytotoxicity of EBB.Different levels of EBB were added to different cell lines at series of time points solely or combined with doxorubicin(DOX) to detect the effect on the expression of cyclinB1 and cdc2-p34 by Western blots.cdc2-p34 tyrosine phosphorylation was detected by immunoprecipitation.In addition,apoptosis and cytoplastic Ca 2+ concentrations were systematically examined by laser scanning confocal microscopy(LSCM). RESULTS EBB showed little inhibitory activity on human umbilical vein endothelial cells(ECV304),whereas EBB inhibited cell growth(IC50 range,4.55~15.74μmol/L)in a variety of sensitive and drug-resistance cell lines.EBB also down-regulated the expression of cyclin B1 and cdc2-p34 in a concentration and time dependent manner,which was an important reason for the G2/M phase arrest.EBB was shown to induce apoptosis of MCF-7/ADR cells while increasing the level of cytoplastic Ca 2+ . CONCLUSION The low cytotoxicity of EBB suggests it may be useful as a rational reversal agent.The effect of EBB on cell cycle arrest and related proteins,apoptosis,and cytoplastic Ca 2+ concentration may be involved in reversing multidrug resistance.
文摘OBJECTIVE: To evaluate the anti-hepatoma effect of Calmodulin antagonist 0 - 4-ethoxyl-butyl-Berbamine (EBB), one of the berbamine derivatives. METHODS: Monotetrazolium (MTT) method was used to analyze the effect of EBB on the proliferation and growth inhibition effect. Of a hepatoma cell line in vitro. A mouse hepatoma model was induced by injection of hepatoma cells (H22) in the abdominal cavity. The effect of EBB on survival at different concentrations as well as in combination with 5-FU were investigated in vivo. Flow cytometry analysis, dot blot hybridization, western blot, immunochemistry, enzyme-linked lectin assay (ELISA), trifluoperazine (TFP) and electron microscopic observation were used to study the effect of EBB on cell cycle process, P53 mRNA and protein levels, calmodulin content and ultrastractural changes of hepatoma cells. RESULTS: EBB exerts a very strong inhibitory effect on human hepatoma cell line 7402 and mouse hepatoma cell line H22 in vitro. The IC(50) value of EBB for the two cell lines are 3.312 microg/ml and 1.167 microg/ml, respectively. The sensitivity of H22 cells to 5-FU can be markedly enhanced: The IC(50) dosage of 5-Fu can be decreased from 0.75 microg/ml down to 0.15 microg/ml, when jointly administered with nontoxic dosages of EBB (IC(10)). In vivo, EBB can prolong the lifespan of mice with ascites H22 to more than three months. 64% of mice survived, while all animals in the control group died by the 18th day. When EBB (5 mg x kg(-1) x d(-1)) is jointly used with 5-FU (25 mg x ml(-1) x d(-1)), 73% of mice with ascites H22 survived, much higher than 27% in the 5-FU treated group. EBB can enhance the anti-hepatoma ability of 5-Fu treatment. EBB mechanism against hepatoma: P53 expression in the EBB treated group is substantially higher than that in the control group. EBB increased the translation of P53. As a calmodulin antagonist, EBB decreases amount of the CaM in hepatoma cells and blocked the hepatoma cell proliferation cycle at the G(2)M phase. Before the G(0)/G(1) phase, a diploid peak and apoptic cells in the treated groups were observed. CONCLUSIONS: The CaM antagonist, EBB, has a strong anti-hepatoma effect and enhances the effect of 5-FU, induces hepatoma cell to apoptosis, promotes the P53 protein expression and decreases the amount of CaM in the cytoplasm. All these results demonstrate that EBB is a new and potentially useful drug against hepatoma and should be researched further.
