The damage process of concrete exposed to sodium sulfate attack and drying-wetting cycles was investigated. The water to binder(W/B) ratio and the concentration of sulfate solution were taken as variable parameters. T...The damage process of concrete exposed to sodium sulfate attack and drying-wetting cycles was investigated. The water to binder(W/B) ratio and the concentration of sulfate solution were taken as variable parameters. Through the experiment, visual change, relative dynamic modulus of elasticity(RDME) and the surface damage layer thickness of concrete were measured.Furthermore, SEM and thermal analysis were used to investigate the changing of microstructure and corrosion products of concrete.The test results show that the ultrasonic velocity is related to the damage layer of concrete. It approves that an increase in damage layer thickness reduces the compactness and the ultrasonic velocity. The deterioration degree of concrete could be estimated effectively by measuring the surface damage layer and the RDME of concrete. It is also found that the content of gypsum in concrete is less than that of ettringite in test, and some gypsum is checked only after a certain corrosion extent. When the concrete is with high W/B ratio or exposed to high concentration of sulfate solution, the content of ettringite first increases and then decreases with corrosion time. However, the content of gypsum increases at a steady rate. The content of corrosion products does not correspond well with the observations of RDME change, and extensive amount of corrosion products can be formed before obvious damage occurs.展开更多
AIM： To investigate apparent diffusion coefficient （ADC） values as an indication of reconditioning of acute hepatic injury （AHI） after allogeneic mononuclear bone marrow cell （MBMC） transplantation. METHODS： T...AIM： To investigate apparent diffusion coefficient （ADC） values as an indication of reconditioning of acute hepatic injury （AHI） after allogeneic mononuclear bone marrow cell （MBMC） transplantation. METHODS： Three groups were used in our study： a cell transplantation group （n = 21）, transplantation control group （n = 21） and normal control group （n = 10）. AHI model rabbits in the cell transplantation group were injected with 5 mL of MBMC suspension at multiple sites in the liver and the transplantation controls were injected with 5 mL D-Hanks solution. At the end of the 1st, 2nd and 4th wk, 7 rabbits were randomly selected from the cell transplantation group and trans- plantation control group for magnetic resonance diffu- sion-weighted imaging （MR-DWI） and measurement of the mean ADC values of injured livers. After MR-DWI examination, the rabbits were sacrificed and the livers subjected to pathological examination. Ten healthy rab- bits from the normal control group were used for MR- DWI examination and measurement of the mean ADC value of normal liver. RESULTS： At all time points, the liver pathological scores from the cell transplantation group were significantly lower than those in the transplantation control group （27.14± 1.46 vs 69.29± 6.16, 22.29 ± 2.29 vs 57.00± 1.53, 19.00 ± 2.31 vs 51.86 ± 6.04, P = 0.000）. The mean ADC values of the cell transplantation group were significantly higher than the transplantation con- trol group （（1.07± 0.07） ×10^-3 mm2/s vs （0.69 ± 0.05） ×10^-3 mm2/s, （1.41± 0.04） ×10^-3 mm2/s vs （0.84± 0.03） ×10^-3 mm2/s, （1.68 ± 0.04） ×10^-3 mm2/s vs （0.86± 0.04） ×10^-3 mm2/s, P = 0.000）. The pathological scores of the cell transplantation group and transplantation control group gradually decreased. However, their mean ADC values gradually increased to near that of the normal control. At the end of the 1st wk, the mean ADC values of the cell transplantation group and transplantation control group were significantly lower than those of the normal control group [（1.07 ± 0.07） ×10^-3 mm2/s vs （± 0.03） ×10^-3 mm2/s, （0.69± 0.05） ×10^-3 mm2/s vs （1.76 ± 0.03） ×10^-3 mm2/s, P = 0.000]. At any 2 time points, the pathological scores and the mean ADC values of the cell transplantation group were significantly different （P = 0.000）. At the end of the 1st wk, the pathological scores and the mean ADC values of the transplantation control group were significantly different from those at the end of the 2nd and 4th wk （P = 0.000）. However, there was no significant difference between the 2nd and 4th wk （P = 0.073 and 0.473, respectively）. The coefficient of correlation between the pathological score and the mean ADC value in the cell transplantation group was -0.883 （P = 0.000） and -0.762 （P = 0.000） in the transplantation control group. CONCLUSION： Tracking the longitudinally dynamic change in the mean ADC value of the AHI liver may reflect hepatic injury reconditioning after allogeneic MBMC transplantation.展开更多
基金Project(51278403)supported by the National Natural Science Foundation of China
文摘The damage process of concrete exposed to sodium sulfate attack and drying-wetting cycles was investigated. The water to binder(W/B) ratio and the concentration of sulfate solution were taken as variable parameters. Through the experiment, visual change, relative dynamic modulus of elasticity(RDME) and the surface damage layer thickness of concrete were measured.Furthermore, SEM and thermal analysis were used to investigate the changing of microstructure and corrosion products of concrete.The test results show that the ultrasonic velocity is related to the damage layer of concrete. It approves that an increase in damage layer thickness reduces the compactness and the ultrasonic velocity. The deterioration degree of concrete could be estimated effectively by measuring the surface damage layer and the RDME of concrete. It is also found that the content of gypsum in concrete is less than that of ettringite in test, and some gypsum is checked only after a certain corrosion extent. When the concrete is with high W/B ratio or exposed to high concentration of sulfate solution, the content of ettringite first increases and then decreases with corrosion time. However, the content of gypsum increases at a steady rate. The content of corrosion products does not correspond well with the observations of RDME change, and extensive amount of corrosion products can be formed before obvious damage occurs.
基金Supported by The National Natural Science Foundation of China,No. 30070235,No. 30470508 and No. 30870695The Natural Science Foundation of Hunan Province,No. 06JJ2008,07JJ6040
文摘AIM： To investigate apparent diffusion coefficient （ADC） values as an indication of reconditioning of acute hepatic injury （AHI） after allogeneic mononuclear bone marrow cell （MBMC） transplantation. METHODS： Three groups were used in our study： a cell transplantation group （n = 21）, transplantation control group （n = 21） and normal control group （n = 10）. AHI model rabbits in the cell transplantation group were injected with 5 mL of MBMC suspension at multiple sites in the liver and the transplantation controls were injected with 5 mL D-Hanks solution. At the end of the 1st, 2nd and 4th wk, 7 rabbits were randomly selected from the cell transplantation group and trans- plantation control group for magnetic resonance diffu- sion-weighted imaging （MR-DWI） and measurement of the mean ADC values of injured livers. After MR-DWI examination, the rabbits were sacrificed and the livers subjected to pathological examination. Ten healthy rab- bits from the normal control group were used for MR- DWI examination and measurement of the mean ADC value of normal liver. RESULTS： At all time points, the liver pathological scores from the cell transplantation group were significantly lower than those in the transplantation control group （27.14± 1.46 vs 69.29± 6.16, 22.29 ± 2.29 vs 57.00± 1.53, 19.00 ± 2.31 vs 51.86 ± 6.04, P = 0.000）. The mean ADC values of the cell transplantation group were significantly higher than the transplantation con- trol group （（1.07± 0.07） ×10^-3 mm2/s vs （0.69 ± 0.05） ×10^-3 mm2/s, （1.41± 0.04） ×10^-3 mm2/s vs （0.84± 0.03） ×10^-3 mm2/s, （1.68 ± 0.04） ×10^-3 mm2/s vs （0.86± 0.04） ×10^-3 mm2/s, P = 0.000）. The pathological scores of the cell transplantation group and transplantation control group gradually decreased. However, their mean ADC values gradually increased to near that of the normal control. At the end of the 1st wk, the mean ADC values of the cell transplantation group and transplantation control group were significantly lower than those of the normal control group [（1.07 ± 0.07） ×10^-3 mm2/s vs （± 0.03） ×10^-3 mm2/s, （0.69± 0.05） ×10^-3 mm2/s vs （1.76 ± 0.03） ×10^-3 mm2/s, P = 0.000]. At any 2 time points, the pathological scores and the mean ADC values of the cell transplantation group were significantly different （P = 0.000）. At the end of the 1st wk, the pathological scores and the mean ADC values of the transplantation control group were significantly different from those at the end of the 2nd and 4th wk （P = 0.000）. However, there was no significant difference between the 2nd and 4th wk （P = 0.073 and 0.473, respectively）. The coefficient of correlation between the pathological score and the mean ADC value in the cell transplantation group was -0.883 （P = 0.000） and -0.762 （P = 0.000） in the transplantation control group. CONCLUSION： Tracking the longitudinally dynamic change in the mean ADC value of the AHI liver may reflect hepatic injury reconditioning after allogeneic MBMC transplantation.
