Molecular modeling of interfacial properties of the hydrogen + water + decane mixture in three-phase equilibrium.

The understanding of interfacial phenomena between H2 and geofluids is of great importance for underground H2 storage, but requires further study. We report the first investigation on the three-phase fluid mixture containing H2, H2O, and n-C10H22. Molecular dynamics simulation and PC-SAFT density gradient theory are employed to estimate the interfacial properties under various conditions (temperature ranges from 298 to 373 K and pressure is up to around 100 MPa). Our results demonstrate that interfacial tensions (IFTs) of the H2-H2O interface in the H2 + H2O + C10H22 three-phase mixture are smaller than IFTs in the H2 + H2O two-phase mixture. This decrement of IFT can be attributed to C10H22 adsorption in the interface. Importantly, H2 accumulates in the H2O-C10H22 interface in the three-phase systems, which leads to weaker increments of IFT with increasing pressure compared to IFTs in the water + C10H22 two-phase mixture. In addition, the IFTs of the H2-C10H22 interface are hardly influenced by H2O due to the limited amount of H2O dissolved in nonaqueous phases. Nevertheless, positive surface excesses of H2O are seen in the H2-C10H22 interfacial region. Furthermore, the values of the spreading coefficient are mostly negative revealing the presence of the three-phase contact for the H2 + H2O + C10H22 mixture under studied conditions.

Molecular insights into fluid-solid interfacial tensions in water + gas + solid systems at various temperatures and pressures.

The fluid-solid interfacial tension is of great importance to many applications including the geological storage of greenhouse gases and enhancing the recovery of geo-resources, but it is rarely studied. Extensive molecular dynamics simulations are conducted to calculate fluid-solid interfacial properties in H2O + gas (H2, N2, CH4, and CO2) + rigid solid three-phase systems at various temperatures (298-403 K), pressures (0-100 MPa), and wettabilities (hydrophilic, neutral, and hydrophobic). Our results on the H2O + solid system show that vapor-solid interfacial tension should not be ignored in cases where the fluid-solid interaction energy is strong or the contact angle is close to 90°. As the temperature rises, the magnitude of H2O's liquid-solid interfacial tension declines because the oscillation of the interfacial density/pressure profile weakens at high temperatures. However, the magnitude of H2O vapor-solid interfacial tension is enhanced with temperature due to the stronger adsorption of H2O. Moreover, the H2O-solid interfacial tension in H2O + gas (H2 or N2) + solid systems is weakly dependent on pressure, while the pressure effects on H2O-solid interfacial tensions in systems with CH4 or CO2 are significant. We show that the assumption of pressure independent H2O-solid interfacial tensions should be cautiously applied to Neumann's method for systems containing non-hydrophilic surfaces with strong gas-solid interaction. Meanwhile, the magnitude of gas-solid interfacial tension increases with pressure and gas-solid interaction. High temperatures generally decrease the magnitude of gas-solid interfacial tensions. Further, we found that the increment of contact angle due to the presence of gases follows this order: H2 < N2 < CH4 < CO2.

Circulating Connective Tissue Growth Factor Is Associated with Diastolic Dysfunction in Patients with Diastolic Heart Failure.

BACKGROUND: Connective tissue growth factor (CTGF) and transforming growth factor ß1 (TGF-ß1) are emerging biomarkers for tissue fibrosis. The aim of this study was to investigate the association between circulating CTGF, TGF-ß1 levels and cardiac diastolic dysfunction in patients with diastolic heart failure (DHF). METHODS: Admitted subjects were screened for heart failure and those with left ventricular (LV) ejection fraction <45% were excluded. Diastolic dysfunction was defined as functional abnormalities that exist during LV relaxation and filling by echocardiographic criteria. Totally 114 patients with DHF and 72 controls were enrolled. Plasma levels of CTGF, TGF-ß1, and B-type natriuretic peptide (BNP) were determined. RESULTS: The plasma CTGF and TGF-ß1 levels increased significantly in patients with DHF. Circulating CTGF and TGF-ß1 levels were correlated with echocardiographic parameter E/e' and diastolic dysfunction grading in DHF patients. In multivariate logistic analysis, CTGF was significantly associated with diastolic dysfunction (odds ratio: 1.027, p < 0.001). Plasma CTGF (AUC: 0.770 ± 0.036, p < 0.001) and CTGF/BNP (AUC: 0.839 ± 0.036, p < 0.001) showed good predictive power to the diagnosis of DHF. CONCLUSIONS: This finding suggested CTGF could be involved in the pathophysiology of diastolic heart failure and CTGF/BNP might have auxiliary diagnostic value on diastolic heart failure.

Correlation between clinic, cumulative, 24h-ambulatory systolic blood pressure, and chronic kidney damage in Chinese elderly.

The aim of this study was to investigate whether clinic, cumulative, and 24h ambulatory systolic blood pressure (SBP) was associated with chronic kidney damage, defind as estimated glomerular filtration rate (eGFR) <60 ml/(min·1.73 m2) and/or microalbuminuria ≥30 mg/L, and, if so, which measurement of SBP is more associated with chronic kidney damage in Chinese elderly. A total of 1207 participants older than 60 years old were included in the final analysis. Clinical blood pressure, cumulative blood pressure exposure was calculated and ambulatory 24h blood pressure was assessed. Multiple logistic regression analysis showed that the clinic (p < .001), cumulative (p = .033), 24h average (p < .001), daytime (p = .001) and nighttime SBP (p = .001) were respectively associated with lower eGFR, and cumulative (p = .008), 24 average (p < .001), daytime (p < .001), and nighttime SBP (p < .001) were the risk factors of microalbuminuria. The degree of correlation were strongest between 24h average SBP and chronic kidney damage (odds ratio, 1.78; 95% confidence interval, 1.46-2.15; p < .001), clinic SBP and eGFR (odds ratio, 1.57; 95% confidence interval, 1.13-2.17; p = .007), nighttime SBP and microalbuminuria (odds ratio, 1.45; 95% confidence interval, 1.05-2.00; p = .024). The likelihood ratio test demonstrated that the introduction of 24h average SBP will improve the goodness of fit of the clinic SBP model(p < .05), while the introduction of cumulative SBP exposure has no such effect(p > .05). Cumulative SBP exposure seems inferior to other measurement in indentifying chronic kidney damage, including decreased GFR and microalbuminuria.