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Background: Type 2 diabetes mellitus (T2DM) is associated with decreased heart rate variability (HRV) with an unclear intermediate mechanism. This study aimed to conduct mediation analysis to explore the impact of various adipose tissues on the relationship between T2DM and HRV. Methods: A total of 380 participants were enrolled for analysis, including 249 patients with T2DM and 131 non-diabetic controls. The thicknesses of four adipose tissues (subcutaneous, extraperitoneal, intraperitoneal, and epicardial) were measured by abdominal ultrasound or echocardiography respectively. HRV was assessed by 24-hour Holter for monitoring both frequency domain indices (LF, HF, and LF/HF) and time domain indices (SDNN, SDANN, SDNN index, rMSSD and pNN50). Mediation analysis was used toexamine whether adipose tissues mediated the relationship between T2DM and each index of HRV. Then, a latent variable - HRV burden - was constructed by structural equation model with selected HRV indices to comprehensively assess the whole HRV. Results: Compared to non-diabetic controls, patients with T2DM exhibited a significant reduction in indices of HRV, and a remarkable increase in the thicknesses of extraperitoneal, intraperitoneal, and epicardial adipose tissues. Mediation analysis found significant indirect effects of T2DM on six indices of HRV, including HF, SDNN, SDANN, SDNN index, rMSSD, and pNN50, which was mediated by epicardial adipose tissue rather than other adipose tissues, with the mediation proportions of 64.21%, 16.38%, 68.33%, 24.34%, 24.10% and 30.51%, respectively. Additionally, epicardial adipose tissue partially mediated the relationship between T2DM and reduced HRV burden (24.26%), which composed by SDNN, SDNN index, rMSSD, and pNN50. Conclusion: Epicardial adipose tissue partially mediated the relationship between T2DM and reduced HRV, which reinforces the value of targeting heart-specific visceral fat to prevent cardiac autonomic neuropathy in diabetes. [ABSTRACT FROM AUTHOR]

The effective dispersion of carbonaceous soot has a critical effect on the friction and wear properties and thus decreases energy waste and equipment trouble. Molecular dynamics (MD) simulation and experimental study are performed to unravel the dispersion behavior and mechanism of soot agglomerate in lubricating system with effect of dispersant concentration at various pressures and temperatures. The static, confinement and shear models were created with dispersant polyisobutylsuccinimide polyamine (pib). At static conditions, pib molecules could approach and then self-assemble on soot fragments to disperse soot agglomerate. Under confinement conditions with an external pressure imposed, soot dispersion was better than that under static conditions, and the effect of pressure was not remarkable. The best dispersion characteristic was obtained as dispersant increased to 10 wt% exceeding that the dispersants were excessive and induced their self-aggregation. Under shear conditions, 10 wt% pib molecules showed the best dispersion at both 300 K and 373 K, which is considered as a critical value for soot dispersion from the perspective of MD simulations. Finally, the tribological experiments provided a prime validation for MD simulations. The most effective lubrication occurred in 12.5 wt% sample with friction and wear reduction by 51% and 80% compared to 10 wt% sample, respectively, due to the well soot dispersion and possible friction modification of dispersants. [Display omitted] • Dispersion of carbonaceous soot is studied by MD simulation and experiment. • Dispersive and interactive mechanisms are revealed in different models. • Good soot dispersion benefits the reduction in friction and wear. [ABSTRACT FROM AUTHOR]

Background: Deposition of adipose tissue may have a promoting role in the development of diabetic complications. This study is aimed at investigating the relationship between adipose tissue thickness and risk of contrast-induced nephropathy (CIN) in patients with Type 2 diabetes mellitus (T2DM). Methods: A total of 603 T2DM patients undergoing percutaneous coronary angiography or angioplasty with suspicious or confirmed stable coronary artery disease were enrolled in this study. The thicknesses of perirenal fat (PRF), subcutaneous fat (SCF), intraperitoneal fat (IPF), and epicardial fat (ECF) were measured by color Doppler ultrasound, respectively. The association of various adipose tissues with CIN was analyzed. Results: Seventy-seven patients (12.8%) developed CIN in this cohort. Patients who developed CIN had significantly thicker PRF (13.7 ± 4.0 mm vs. 8.9 ± 3.6 mm, p < 0.001), slightly thicker IPF ( p = 0.046), and similar thicknesses of SCF ( p = 0.782) and ECF ( p = 0.749) compared to those who did not develop CIN. Correlation analysis showed that only PRF was positively associated with postoperation maximal serum creatinine (sCr) ( r = 0.18, p = 0.012), maximal absolute change in sCr ( r = 0.33, p < 0.001), and maximal percentage of change in sCr ( r = 0.36, p < 0.001). In receiver operating characteristic (ROC) analysis, the area under the curve (AUC) of PRF (0.809) for CIN was significantly higher than those of SCF (0.490), IPF (0.594), and ECF (0.512). Multivariate logistic regression analysis further confirmed that thickness of PRF, rather than other adipose tissues, was independently associated with the development of CIN after adjusted for confounding factors (odds ratio (OR) = 1.53, 95% CI: 1.38-1.71, p < 0.001). Conclusions: PRF is independently associated with the development of CIN in T2DM patients undergoing coronary catheterization., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Xixiang Tang et al.)