Homocysteine (Hcy) is a risk factor for atherosclerosis. It is generally accepted that inducible nitric oxide synthase (iNOS) is a key enzyme in the

To study the strength increasing rule of LWSCC in the process of freezing construction, some specimens were placed in cryogenic boxes at different subzero temperatures for curing, and the others were used as a control group for standard curing. After standard curing for 28 days, the specimens were placed in cryogenic boxes at different subzero temperatures for 1 day, and then the specimens were subjected to quasi-static loading and split Hopkinson pressure bar (SHPB) dynamic impact tests. Results showed that LWSCC had a stronger anti-freezing ability than the ordinary concrete and the strength growth was sensitive to the curing temperature. As the curing temperature decreased, the increasing rates of the compressive and tensile strengths became slow. The quasi-static and dynamic mechanical experiments showed that the strength of LWSCC was substantially enhanced when subjected to cryogenic temperatures after standard curing. Cryogenic LWSCC exhibited an obvious strain rate effect and impact resistance. A two-factor incremental model of the dynamic stress intensity factors and the dynamic constitutive equation of LWSCC in cryogenic temperatures were constructed. The conclusions obtained in the study provide a theoretical basis for the design of impact-resistant structures in cold areas.

Due to the periodicity of mine pressure, it can easily lead to a wide-range damage of the overburden rock under shallow coal mining conditions, and the falling of the overburden rock is usually a serious threat to the mining safety. Based on the monitoring data of mine pressure in a typical shallow coal mine in northern China, the mechanical model of the surrounding rock in the mining field was built and the identification indicators of the pressure arch after coal mining was defined. Then, the arching mechanism, the stress distribution characteristics in different positions, and the bearing capacity of the pressure arch were analysed, and the evolution characteristics of the pressure arch under shallow horizontal coal mining were verified by numerical simulation and physical experiment. Results show that there is a core-bearing zone in the pressure arch, and the width of the core zone determines the bearing capacity of the pressure arch. The evolution of the pressure arch affects the formation and development of the caving arch of the loose zone in the mining field. The conclusions obtained in the study are of important theoretical value to direct the similar engineering practice.