The homeodomain transcription factor Nkx2.5/Csx is critically essential for heart specification, morphogenesis, and homeostasis. Acetylation/deacetylation is important for the localization, stability and activation of transcription factors. It remains unknown how Nkx2.5 is deacetylated and how Nkx2.5 acetylation determines its activity. In this study, we provide evidence that the NAD+-dependent class III protein deacetylase SIRT1 deacetylates Nkx2.5 in cardiomyocytes and represses the transcriptional activity of Nkx2.5. We show that SIRT1 interacts with the C-terminus of Nkx2.5 and deacetylates Nkx2.5 at lysine 182 in the homeodomain. The mutation of Nkx2.5 at lysine 182 reduces its transcriptional activity. Furthermore, SIRT1 inhibits the transcriptional activity of Nkx2.5 and represses the expression of its target genes partly by reducing Nkx2.5 binding to its co-factors, including SRF and TBX5. Taken together, these findings demonstrate that SIRT1 deacetylates Nkx2.5 and inhibits the transcriptional activity of Nkx2.5.

Engineered cementitious composite (ECC) is a class of high performance cementitious composites with pseudo strain hardening behavior and excellent crack control. Substitution of concrete with ECC can avoid the cracking and durability problems associated with brittleness of concrete. In this paper, it is aimed to design a scale model of ECC reinforced concrete precast shear wall structure. Referencing the prototype structure which is a precast concrete shear wall structure in Nantong, Jiangsu Province, China, the size similarity constant is taken as 1/2. Consulting the scale similarity conditions, the similarity similar constants representing material characteristics, geometrical features, and load characteristics are calculated using the strength similarity theory. Besides, the reinforcements in the model structure are calculated and analyzed. The diameters of reinforcing steel bars in the model structure are determined by the principle of similar size. Equivalent principle of yield bearing capacity are used when there is no corresponding reinforcement selection. The research results of this paper will provide valuable preferences for design and analysis of ECC reinforced concrete precast shear wall structure.

To study the working behavior of a rigid pile composite foundation of high-rise buildings, an in-situ loading test and stress test on piles and soil were carried out. According to the test results, the stress distributions and variations, load transferring characteristics, and stress distributions of piles were analyzed. The results showed that the piles with the formation of non-soil compaction technology can consolidate soil among piles. When the load level was greater than 240 kPa, a better consolidation effect can be obtained. The development negative friction at the top of piles was relevant to the load level. The adjustment effect of cushion on the composite foundation was mainly embodied before the load level reached the characteristic bearing capacity of the composite foundation. Under vertical load, the stress distributions along the internal and external sides of pile shaft were different and the loading plate would bring influence to stress distributions of the pile shaft. The influence range was from the middle to the top of the pile. Based on the test results, it is recommended to reduce the evaluation standard of the bearing capacity determined in the pressing plate test. The results can provide a reference for similar engineering.

：In order to accurately predict the dynamic output characteristics of M-EHA, a nonlinear dynamics model considering fluid bulk modulus and density variation is proposed. The intrinsic nonlinearity of giant magnetostrictive materials is described by the Jiles-Atherton model. The overall fluid transmission characteristics are modeled by coupling the valve vibration equation, the flow equation, the fluid lines pressure drop equation and the hydraulic cylinder dynamic equation. In order to study the effects of modulus and density variation during high-pressure fluid transmission, the fluid equivalent modulus is treated as a function of pressure, and the effects of fluid compressibility, inertia and viscosity on the output characteristics of M-EHA are studied based on electro-hydraulic analogies theory. Finally, the nonlinear dynamic model of the whole actuation system is established. The model is iteratively solved by the fourth-order Runge-Kutta method. Combined with the experimental comparison, the relationship between driving frequency, bias pressure, load and output performance of the operating system is studied. The results show that the output performance of the actuation system varies bimodally with the driving frequency, and as the biase pressure increases, the peak frequency rises and the optimal output level is reached at 2.6 MPa bias. It lays a theoretical foundation for the design development and optimization of high-performance M-EHA.

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