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The etiology of preeclampsia (PE), a complex and multifactorial condition, remains incompletely understood. DNA methylation, which is primarily regulated by three DNA methyltransferases (DNMTs), DNMT1, DNMT3A, and DNMT3B, plays a vital role in early embryonic development and trophectoderm differentiation. Yet, how DNMTs modulate trophoblast fusion and PE development remains unclear. In this study, we found that the DNMTs expression was downregulated during trophoblast cells fusion. Downregulation of DNMTs was observed during the reconstruction of the denuded syncytiotrophoblast (STB) layer of placental explants. Additionally, overexpression of DNMTs inhibited trophoblast fusion. Conversely, treatment with the DNA methylation inhibitor 5‐aza‐CdR decreased the expression of DNMTs and promoted trophoblast fusion. A combined analysis of DNA methylation data and gene transcriptome data obtained from the primary cytotrophoblasts (CTBs) fusion process identified 104 potential methylation‐regulated differentially expressed genes (MeDEGs) with upregulated expression due to DNA demethylation, including CD59, TNFAIP3, SDC1, and CDK6. The transcription regulation region (TRR) of TNFAIP3 showed a hypomethylation with induction of 5‐aza‐CdR, which facilitated CREB recruitment and thereby participated in regulating trophoblast fusion. More importantly, clinical correlation analysis of PE showed that the abnormal increase in DNMTs may be involved in the development of PE. This study identified placental DNA methylation‐regulated genes that may contribute to PE, offering a novel perspective on the role of epigenetics in trophoblast fusion and its implication in PE development. [ABSTRACT FROM AUTHOR]

Hollow structural steel (HSS) columns filled with concrete offer a number of benefits and are often used in tall buildings and other industrial structures. A mathematical model was developed and used to investigate the influence of important parameters that determine the fire resistance of concrete-filled hollow steel columns. The behavior of concrete-filled HSS columns with or without fire protection subjected to axial or eccentric loads was experimentally investigated and the results presented in this paper. The parametric and experimental studies provide information for the development of formulas for the calculation of the fire resistance and fire protection thickness of the composite columns. The main objectives of this work were threefold: First, to report a series of fire tests on composite columns; second, to analyze the influence of several parameters, such as the sectional dimension, load eccentricity ratio, and fire protection thickness on the fire resistance of the composite columns. It was found, in general, that the sectional dimension and the fire protection thickness have significant influence on the fire resistance of concrete-filled HSS columns; however, the load eccentricity ratio has moderate influence on the fire resistance. The final objective was to develop formulas for the calculation of the fire resistance and the fire protection thickness of the concrete-filled HSS columns. CE Database keywords: Steel columns; Fire resistance; Concrete; Beam columns; Hollow sections.

This paper describes research work on the performance and design calculations of recycled aggregate concrete filled steel tube (RACFST) members, especially the most recent developments in China. Firstly, experimental studies on RACFST members subjected to short-term static loading, long-term sustained loading and cyclic flexural loading are summarised and analysed, and recent advances in the behaviour of RACFST stub columns after exposure to high temperatures (300-800°C) are also reviewed. The experimental results show that, in general, RACFST members have similar performance to concrete filled steel tube (CFST) members when subjected to the same loading conditions. However, due to the more serious inherent defects of recycled aggregate concrete compared with normal concrete, RACFST members have a lower bearing capacity and stiffness than their CFST counterparts. Secondly, design formulae for RACFST members are suggested and the calculated bearing capacities using the simplified equations generally agree well with the experimental results. Finally, the potential research needs of RACFST structures are discussed. [ABSTRACT FROM AUTHOR]