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receptor antagonist reduces hepatic resistance and portal pressure through enhanced eNOS-dependent HSC

Ruoxi Zhang, Jing Chen, Diangang Liu, Yu Wang

《医学前沿（英文）》 2019年第13卷第3期页码 398-408 doi: 10.1007/s11684-019-0689-5

摘要： Increased serum urotensin II (UII) levels in human cirrhotic populations have been recently shown, but the long-term effects of UII receptor antagonist on the cirrhosis have not been investigated. To investigate the therapeutic effects of urotensin II receptor (UT) antagonist palosuran on rats with carbon tetrachloride (CCl )-induced cirrhosis, the hepatic and systemic hemodynamics, liver fibrosis, the metalloproteinase-13 (MMP-13)/ tissue inhibitor of metalloproteinase-1 (TIMP-1) ratio, hepatic Rho-kinase activity, and the endothelial nitric oxide synthase (eNOS) activity are measured in CCl -cirrhotic rats treated with palosuran or vehicle for 4 weeks. Primary hepatic stellate cells (HSCs) are used to investigate the changes in UII/UT expression and the effect of palosuran. Compared with the vehicle-treated cirrhotic rats, treatment with palosuran can reduce the portal pressure (PP), decrease the risk of liver fibrosis and the level of α smooth muscle actin, collagen-I (COL-I), and transforming growth factor β expression. However, treatment with palosuran can increase MMP-13/TIMP-1, p-vasodilator-stimulated phosphoprotein (p-VASP), and p-eNOS expression. Moreover, UII/UT mRNA expression increases during HSC activation. MMP-13/TIMP-1, COL-I, and p-VASP are inhibited after palosuran treatment. Our data indicate that long-term administration of palosuran can decrease PP in cirrhosis, which results from decreased hepatic fibrosis and enhanced eNOS-dependent HSC vasodilatation.

关键词： portal hypertension cirrhosis urotensin II palosuran hepatic stellate cell

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Degradation of permeability resistance of high strength concrete after combustion

LI Min, QIAN Chunxiang, KAO Hongtao

《结构与土木工程前沿（英文）》 2008年第2卷第3期页码 281-287 doi: 10.1007/s11709-008-0031-9

摘要： To evaluate the remaining durability of concrete materials after combustion, the permeability of high strength concrete (HSC) after combustion was studied. The transport behavior of chloride ion, water and air in concrete after combustion and the effect of temperature, strength grade, and aggregation on the permeability of HSC after combustion are investigated by chloride ion permeability coefficient (), water permeability coefficient () and air permeability coefficient (). The experiment results show that all three permeability coefficients commendably reflect changes of permeability. The permeability coefficient increases with the evaluation temperature. After the same temperature, the permeability coefficient of HSC is lower than that of normal strength concrete (NSC). However, the degree of degradation of permeability coefficient of HSC is greater than that of NSC. The permeability resistance of HSC containing limestone is better than that of HSC containing basalt. Combining changes of compressive strength and permeability, the remaining durability of concrete materials after combustion is appropriately evaluated.

关键词： transport behavior limestone durability permeability HSC

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An experimental study on the flexural behavior of heavily steel reinforced beams with high-strength concrete

Yasser SHARIFI, Ali Akbar MAGHSOUDI

《结构与土木工程前沿（英文）》 2014年第8卷第1期页码 46-56 doi: 10.1007/s11709-014-0237-y

摘要： In recent years, an emerging technology termed high-strength concrete (HSC) has become popular in construction industry. Present study describes an experimental research on the behavior of high-strength concrete beams in ultimate and service state. Six simply supported beams were tested, by applying comprising two symmetric concentrated loads. Tests are reported in this study on the flexural behavior of high-strength reinforced concrete (HSRC) beams made with coarse and fine aggregate together with Microsilica. Test parameter considered includes effect of being compressive reinforcement. Based on the obtained results, the behavior of such members is more deeply reviewed. Also a comparison between theoretical and experimental results is reported here. The beams were made from concrete having compressive strength of 66.81–77.72 N/mm and percentage reinforcement ratio ( / ) in the range of 0.56% – 1.20%. The ultimate moment for the tested beams was found to be in a good agreement with that of the predicted ultimate moment based on ACI 318-11, ACI 363 and CSA-04 provisions. The predicted deflection based classical formulation based on code provisions for serviceability requirements is found to underestimate the maximum deflection of HSC reinforced beams at service load.

关键词： high-strength concrete (HSC) members flexural behavior reinforced concrete experimental results ultimate moment