Calculation of and Key Influencing Factors Analysis on Equivalent Resilient Modulus of a Submerged Subgrade.

To calculate and analyze the equivalent resilient modulus of a submerged subgrade, a constitutive model considering the effect of saturation and matrix suction was introduced using ABAQUS's user-defined material (UMAT)subroutine. The pavement response under falling weight deflectometer (FWD) load was simulated at various water levels based on the derived distribution of the resilient modulus within the subgrade. The equivalent resilient modulus of the subgrade was then calculated using the equivalent iteration and weighted average methods. Based on this, the influence of the material and structural parameters of the subgrade was analyzed. The results indicate that the effect of water level rise on the tensile strain at the bottom of the asphalt layer and the compressive strain at the top of the subgrade is obvious, and its trend is similar to an exponential change. The equivalent resilient modulus of the subgrade basically decreases linearly with the rise in the water level, and there is high consistency between the equivalent iteration and weighted average methods. The saturated permeability coefficient and subgrade height have the most significant effect on the resilient modulus of the subgrade, which should be emphasized in the design of submerged subgrades, and the suggested values of the resilient modulus of the subgrade should be proposed according to the relevant construction conditions.

Investigation of Adhesion Properties of Tire-Asphalt Pavement Interface Considering Hydrodynamic Lubrication Action of Water Film on Road Surface.

To obtain the tire−pavement peak adhesion coefficient under different road states, a field measurement and FE simulation were combined to analyze the tire−pavement adhesion characteristics in this study. According to the identified texture information, the power spectral distribution of the road surface was obtained using the MATLAB Program, and a novel tire hydroplaning FE model coupled with a textured pavement model was established in ABAQUS. Experimental results show that here exists an "anti-skid noncontribution area" for the insulation and lubrication of the water film. Driving at the limit speed of 120 km/h, the critical water film thickness for the three typical asphalt pavements during hydroplaning was as follows: AC pavement, 0.56 mm; SMA pavement, 0.76 mm; OGFC pavement, 1.5 mm. The road state could be divided into four parts dry state, wet sate, lubricated state, and ponding state. Under the dry road state, when the slip rate was around 15%, the adhesion coefficient reached the peak value, i.e., around 11.5% for the wet road state. The peak adhesion coefficient for the different asphalt pavements was in the order OGFC > SMA > AC. This study can provide a theoretical reference for explaining the tire−pavement interactions and improving vehicle brake system performance.

ZnT8 Deficiency Protects From APAP-Induced Acute Liver Injury by Reducing Oxidative Stress Through Upregulating Hepatic Zinc and Metallothioneins.

Zinc transporter 8 (ZnT8) is an important zinc transporter highly expressed in pancreatic islets. Deficiency of ZnT8 leads to a marked decrease in islet zinc, which is thought to prevent liver diseases associated with oxidative stress. Herein, we aimed to investigate whether loss of islet zinc affects the antioxidant capacity of the liver and acute drug-induced liver injury. To address this question, we treated ZnT8 knockout (KO) or wild-type control mice with 300 mg/ kg acetaminophen (APAP) or phosphate-buffered saline (PBS). Unexpectedly, we found that loss of ZnT8 in mice ameliorated APAP-induced injury and was accompanied by inhibition of c-Jun N-terminal kinase (JNK) activation, reduced hepatocyte death, and decreased serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). An increase in hepatic glutathione (GSH) was observed, corresponding to a decrease in malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) levels. APAP-induced inflammation and glycogen depletion were alleviated. In contrast, no significant changes were observed in cytochrome P450 family 2 subfamily E member 1 (CYP2E1), the main enzyme responsible for drug metabolism. Elevated levels of hepatic zinc and metallothionein (MT) were also observed, which may contribute to the hepatoprotective effect in ZnT8 KO mice. Taken together, these results suggest that ZnT8 deficiency protects the liver from APAP toxicity by attenuating oxidative stress and promoting hepatocyte proliferation. This study provides new insights into the functions of ZnT8 and zinc as key mediators linking pancreatic and hepatic functions.