This paper reports the nanoindentation results of three bituminous binders,C-Fix,and standard penetration grade 40/60 bitumen and organo-montmorillonite (OMt) modified bitumen. Under a load applied by the Berkovich di...This paper reports the nanoindentation results of three bituminous binders,C-Fix,and standard penetration grade 40/60 bitumen and organo-montmorillonite (OMt) modified bitumen. Under a load applied by the Berkovich diamond indenter,a loading and unloading history was recorded and the load-displacement curve was analyzed as a function of time. The software can directly give an output value of the modulus for C-Fix. However the result was dependent on the loading history. Due to increasing viscoelastic behaviour,the output value of the modulus for base bitumen was always negative,even with a very short unloading time. In conclusion,the modulus calculated by the software was not suitable for the bituminous binders due to their time-dependence. The nanoindentation curve during the loading phase of bitumen could be described by the adopted creep model. The results indicated that the OMt modified bitumen showed a high creep resistance than the base bitumen due to the OMt's reinforcement.展开更多
Backround N-terminal pro-brain natriuretic peptide （NT-proBNP） is a reliable predictor in acute coronary artery disease （CAD）. Little is known about patients with stable CAD, especially Chinese patients with CAD. ...Backround N-terminal pro-brain natriuretic peptide （NT-proBNP） is a reliable predictor in acute coronary artery disease （CAD）. Little is known about patients with stable CAD, especially Chinese patients with CAD. The aim of the present study was to investigate the association of NT-proBNP levels with the severity of CAD in patients with normal left ventricular ejection fraction. Methods A total of 658 consecutive patients were divided into two groups based on angiograms： CAD group （n=484） and angiographic normal control group （n=174）. The severity of CAD was evaluated by modified Gensini score, and its relationship with NT-proBNP was analyzed. Results The prevalence of risk factors such as age, male gender, diabetes mellitus （DM）, dyslipidemia, smoking, and family history of CAD in the CAD group were higher than that in the control group. In multivariate regression model analysis, age, gender, and DM were determinants of the presence of CAD. NT-pro BNP was found to be an independent predictor for CAD （OR：1.66 （95% CI： 1.06-2.61）, P 〈0.05）. In a receiver operating characteristic （ROC）curve analysis, an NT-proBNP value of 641.15 pmol/L was identified as a cut-off value in the diagnosis or exclusion of CAD （area under curve （AUC）=0.56, 95% CI： 0.51-0.61）. Furthermore, NT-proBNP was positively correlated with Gensini score （r=0.14, P 〈0.001） in patients with CAD. Conclusion NT-proBNP was an independent predictor for Chinese patients with CAD, suggesting that the NT-proBNP level might be associated with the presence and the severity of CAD.展开更多
文摘This paper reports the nanoindentation results of three bituminous binders,C-Fix,and standard penetration grade 40/60 bitumen and organo-montmorillonite (OMt) modified bitumen. Under a load applied by the Berkovich diamond indenter,a loading and unloading history was recorded and the load-displacement curve was analyzed as a function of time. The software can directly give an output value of the modulus for C-Fix. However the result was dependent on the loading history. Due to increasing viscoelastic behaviour,the output value of the modulus for base bitumen was always negative,even with a very short unloading time. In conclusion,the modulus calculated by the software was not suitable for the bituminous binders due to their time-dependence. The nanoindentation curve during the loading phase of bitumen could be described by the adopted creep model. The results indicated that the OMt modified bitumen showed a high creep resistance than the base bitumen due to the OMt's reinforcement.
基金Wu Naqiong and Ma Fenglian contributed equally to this study. This work is partly supported by grants from National Natural Scientific Foundation of China （No. 81070171 and No. 81241121）, Specialized Research Fund for the Doctoral Program of Higher Education of China （No. 20111106110013）, Capital Special Foundation of Clinical Application Research （No. Z121107001012015）, Capital Health Development Fund （No. 2011400302）, and Beijing Natural Science Foundation （No. 7131014） No conflict of interest needs to be declared.
文摘Backround N-terminal pro-brain natriuretic peptide （NT-proBNP） is a reliable predictor in acute coronary artery disease （CAD）. Little is known about patients with stable CAD, especially Chinese patients with CAD. The aim of the present study was to investigate the association of NT-proBNP levels with the severity of CAD in patients with normal left ventricular ejection fraction. Methods A total of 658 consecutive patients were divided into two groups based on angiograms： CAD group （n=484） and angiographic normal control group （n=174）. The severity of CAD was evaluated by modified Gensini score, and its relationship with NT-proBNP was analyzed. Results The prevalence of risk factors such as age, male gender, diabetes mellitus （DM）, dyslipidemia, smoking, and family history of CAD in the CAD group were higher than that in the control group. In multivariate regression model analysis, age, gender, and DM were determinants of the presence of CAD. NT-pro BNP was found to be an independent predictor for CAD （OR：1.66 （95% CI： 1.06-2.61）, P 〈0.05）. In a receiver operating characteristic （ROC）curve analysis, an NT-proBNP value of 641.15 pmol/L was identified as a cut-off value in the diagnosis or exclusion of CAD （area under curve （AUC）=0.56, 95% CI： 0.51-0.61）. Furthermore, NT-proBNP was positively correlated with Gensini score （r=0.14, P 〈0.001） in patients with CAD. Conclusion NT-proBNP was an independent predictor for Chinese patients with CAD, suggesting that the NT-proBNP level might be associated with the presence and the severity of CAD.
