Reactive Molecular Simulation on Water Confined in the Nanopores of the Calcium Silicate Hydrate Gel: Structure, Reactivity, and Mechanical Properties

Calcium silicate hydrate (C–S–H) is a mesoporous amorphous material with water confined in the gel pores, which provides the medium for investigating the structure, dynamics, and mechanical properties of the ultraconfined interlayer water molecules. In this study, C–S–H gels with different compositions expressed in terms of the Ca/Si ratio are characterized in the light of molecular dynamics. It is found that with increasing Ca/Si ratio, the molecular structure of the silicate skeleton progressively transforms from an ordered to an amorphous structure. The calcium silicate skeleton, representative of the substrate, significantly influences the adsorption capability, reactivity, H-bond network, and mobility of the interlayer water molecules. The structures were tested for mechanical properties by simulated uniaxial tension, and the mechanical tests associated with structural analysis reveal that the stiffness and cohesive force of C–S–H gel is weakened by both breakage of silicate chains and penetration of water molecules. In addition, the reactive force field is coupled with both the mechanical response and chemical response during the large tensile deformation process. On the one hand, the silicate chains, acting in a skeletal role in the layered structure, depolymerize to enhance the loading resistance. On the other hand, water molecules, attacking the Si–O and Ca–O bonds, dissociate into hydroxyls, which are detrimental to the cohesive force development

Insight into the <i>in situ</i> copolymerization of monomers on cement hydration and the mechanical performance of cement paste

Concrete usually possesses advantages of high compressive strength but weaknesses of low tensile strength originating from the intrinsic brittleness of cement hydrates. Here we propose a method of in situ copolymerization of monomers that use acrylic acid (AA) and acrylamide (AM) to restrain the brittleness of cement hydrates by in situ copolymerization during cement hydration and to enhance the mechanical strength of the cement matrix. Cement pastes with reinforced flexural strength and compressive strength can be obtained by modulating the fraction of AA-AM copolymer. With the polymerization reaction, a polymer skeleton was constructed in the cement matrix, followed by crosslinking with cement hydrates by the coordination between metal ions (Ca2+ and Al3+) and carboxy groups, enhancing the flexural strength and toughness of cement pastes. Our work offers a straightforward method to reduce the intrinsic brittleness of cement hydrates, providing a facile access to cementitious materials with improved flexural performance.</p

Additional file 2 of IGF-1C domain–modified hydrogel enhanced the efficacy of stem cells in the treatment of AMI

Additional file 2: Table S2. RT-PCR primer sequences (mouse)

Additional file 1 of IGF-1C domain–modified hydrogel enhanced the efficacy of stem cells in the treatment of AMI

Additional file 1: Table S1. RT-PCR primer sequences (human)

Surface Engineering of Migratory Corrosion Inhibitors: Controlling the Wettability of Calcium Silicate Hydrate in the Nanoscale

Migratory corrosion inhibitors (MCIs) are regarded as effective additives to prevent harmful ion transmission and improve concrete durability, but their behavior in the porosity of concrete is still unclarified. This paper proposes a unique perspective to evaluate the effects of surfactant-like MCIs in calcium silicate hydrate (C–S–H) nanoporosity through molecular and electronic structural information. Advanced enhanced sampling methods and perturbation theory methods were applied to evaluate the role of different MCIs. The reduced density gradient of MCI molecules was obtained by using quantum chemical calculations. This calculation is instrumental in elucidating the intensity of interactions among distinct MCI molecule head groups and the C–S–H matrix. It is found that MCIs can effectively improve the interfacial tension (IFT) between C–S–H and water, which corresponds to the inhibitory ability of transmission. Free energy indicates that the MCI has the properties of strong adsorption and weak dissolution, facilitating the improvement of IFT. The relationship between the MCI functional group and the ability of adsorption and dissolution is revealed. This study suggests that MCIs work as surface controllers of C–S–H pores and that their properties can be assessed on the nanoscale

Additional file 2 of IGF-1C domain–modified hydrogel enhanced the efficacy of stem cells in the treatment of AMI

Additional file 2: Table S2. RT-PCR primer sequences (mouse)

Additional file 3 of IGF-1C domain–modified hydrogel enhanced the efficacy of stem cells in the treatment of AMI

Additional file 3: Figure S1. Characterization of CS-IGF-1C hydrogel and anti-apoptotic in NMVCs. (A) IGF-1C was grafted onto CS by a click reaction between the azide of IGF-1C-N3 and the alkyne of alkynyl-CS. (B) The thermosensitive CS-IGF-1C hydrogel neutralized with β-GP were liquid at 4 °C and cross-linked into hydrogel at 37 °C. (C) The protective effects of CS-IGF-1C hydrogel and hP-MSCs co-transplantation on NMVCs

Additional file 3 of IGF-1C domain–modified hydrogel enhanced the efficacy of stem cells in the treatment of AMI

Additional file 3: Figure S1. Characterization of CS-IGF-1C hydrogel and anti-apoptotic in NMVCs. (A) IGF-1C was grafted onto CS by a click reaction between the azide of IGF-1C-N3 and the alkyne of alkynyl-CS. (B) The thermosensitive CS-IGF-1C hydrogel neutralized with β-GP were liquid at 4 °C and cross-linked into hydrogel at 37 °C. (C) The protective effects of CS-IGF-1C hydrogel and hP-MSCs co-transplantation on NMVCs

Additional file 1 of IGF-1C domain–modified hydrogel enhanced the efficacy of stem cells in the treatment of AMI

Additional file 1: Table S1. RT-PCR primer sequences (human)

DataSheet1_Maternal Factor Dppa3 Activates 2C-Like Genes and Depresses DNA Methylation in Mouse Embryonic Stem Cells.docx

Mouse embryonic stem cells (ESCs) contain a rare cell population of “two-cell embryonic like” cells (2CLCs) that display similar features to those found in the two-cell (2C) embryo and thus represent an in vitro model for studying the progress of zygotic genome activation (ZGA). However, the positive regulator determinants of the 2CLCs’ conversion and ZGA have not been completely elucidated. Here, we identify a new regulator promoting 2CLCs and ZGA transcripts. Through a combination of overexpression (OE), knockdown (KD), together with transcriptional analysis and methylome analysis, we find that Dppa3 regulates the 2CLC-associated transcripts, DNA methylation, and 2CLC population in ESCs. The differentially methylated regions (DMRs) analysis identified 6,920 (98.2%) hypomethylated, whilst only 129 (1.8%) hypermethylated, regions in Dppa3 OE ESCs, suggesting that Dppa3 facilitates 2CLCs reprogramming. The conversion to 2CLCs by overexpression of Dppa3 is also associated with DNA damage response. Dppa3 knockdown manifest impairs transition into the 2C-like state. Global DNA methylome and chromatin state analysis of Dppa3 OE ESCs reveal that Dppa3 facilitates the chromatin configuration to 2CLCs reversion. Our finding for the first time elucidates a novel role of Dppa3 in mediating the 2CLC conversion, and suggests that Dppa3 is a new regulator for ZGA progress.</p