Sequestration of carbon dioxide (CO(2)) in deep, geological formations involves the injection of supercritical CO(2) into depleted reservoirs containing fluids such as brine or oil. The interfacial tension (IFT) between supercritical CO(2) and the reservoir fluid is an important contribution to the sequestration efficiency. In turn, the IFT is a complex function of the reservoir fluid phase composition, the molecular structure of each reservoir fluid component, and environmental conditions (i.e., temperature and pressure). Molecular dynamics simulations can be used to probe the dependence of the IFT on these factors, since the IFT can be calculated directly from the simulated atomic forces and velocities at system equilibrium using the mechanical definition of the IFT. Here, we examine the contribution of each type of atomic force to the IFT, including bonded and nonbonded forces, as quantified by the anisotropy of the atomic virial tensor. In particular, we first examine a supercritical CO(2)-pure liquid water interface, at typical reservoir conditions (temperature of 343 K and pressure of 20 MPa), as a reference state against which CO(2)-brine systems can be compared. In this system, we note that the interactions between water molecules and between CO(2) molecules ("self" interactions) contribute positively to the IFT, while the interactions between water and CO(2) molecules ("cross" interactions) contribute negatively to the IFT. We find that the magnitude of the water "self" interactions is the dominant contribution. In terms of specific types of forces, we find that nonbonded electrostatic (QQ), bonded angle-bending, and bonded bond-stretching interactions contribute positively to the IFT, while nonbonded Lennard-Jones (LJ) interactions contribute negatively to the IFT. We also find that the balance between the LJ interactions and the bond-stretching interactions, in particular, plays a significant role in determining the magnitude of the IFT. Using orientational probability distribution functions to study molecular ordering about the interface, we find that the CO(2) molecules prefer to lie parallel to the interface at the Gibbs dividing surface (GDS) and that both the CO(2) and the water molecules are more ordered at the GDS than in the bulk. Finally, we present an initial study of a CO(2)-brine system with CaCl(2) as the model salt at a concentration of 2.7 M. We quantify the effect of the salt on the molecular orientation of water, and show that this effect leads to an increase in the IFT, relative to the CO(2)-water system, which is consistent with experimental measurements.
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JACC Adv
January 2025
Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, Georgia, USA. Electronic address:
Background: HIV induced endothelial dysfunction (ED) contributes to cardiovascular disease (CVD) in women with HIV (WWH). Although psychosocial stress has been implicated in the development of CVD in HIV, its impact on ED in WWH remains unknown.
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ISME J
January 2025
HADAL & Nordcee, Department of Biology, University of Southern Denmark, Odense, Denmark.
Auxiliary metabolic genes encoded by bacteriophages can influence host metabolic function during infection. In temperate phages, auxiliary metabolic genes may increase host fitness when integrated as prophages into the host genome. However, little is known about the contribution of prophage-encoded auxiliary metabolic genes to host metabolic properties.
View Article and Find Full Text PDFJMIR Res Protoc
January 2025
School of Advanced Science and Technology, Japan Advanced Institute of Science and Technology, Nomi, Japan.
Background: The worldwide rise in the prevalence of noncommunicable diseases has increased the recognition of the need to identify modifiable risk factors for preventing and managing these diseases. The office worker, as a representative group of physically inactive workers, is exposed to risk factors for metabolic syndrome, which is a primary driver of noncommunicable diseases. The use of virtual reality (VR) exergames may offer a potential solution to the problem of increasing noncommunicable disease prevalence, as it can help individuals increase their physical activity levels while providing a more immersive experience.
View Article and Find Full Text PDFInt Ophthalmol
January 2025
Department of Ophthalmology, The Second Hospital of Jilin University, #218 Ziqiang Street, Changchun, 130041, Jilin, China.
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Naunyn Schmiedebergs Arch Pharmacol
January 2025
Department of Chemistry, Faculty of Science, Cairo University, Giza, 12613, Egypt.
Piperazine-based compounds have garnered significant attention due to their notable biological and pharmacological activities, making them essential in fine chemical and pharmaceutical applications. In this study, we managed to synthesize a novel hybrid bis-cyanoacrylamide bearing the piperazine core via phenoxymethyl linker and incorporating sulphamethoxazole moiety. The novel compound was fully characterized using different spectral data including 1H-NMR, C-NMR, and FTIR spectroscopy.
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