First-principles calculations of high pressure and temperature properties of Fe_(7)C_(3)

Eckstrom-adcock iron carbide(Fe_(7)C_(3))is considered to be the main constituent of the Earth’s inner core due to its low shear wave velocity.However,the crystal structure of Fe_(7)C_(3)remains controversial and its thermoelastic properties are not well constrained at high temperature and pressure.Based on the first-principles simulation method,we calculate the relative phase stability,equation of state,and sound velocity of Fe_(7)C_(3)under core condition.The results indicate that the orthorhombic phase of Fe_(7)C_(3)is stable under the core condition.While Fe_(7)C_(3)does reproduce the low shear wave velocity and high Poisson’s ratio of the inner core,its compressional wave velocity and density are 12%higher and 6%lower than those observed in seismic data,respectively.Therefore,we argue that carbon alone cannot completely explain the thermal properties of the inner core and the inclusion of other light elements may be required.

The effect of adjuvant N-acetylcysteine effervescent tablets therapy on cardiopulmonary function and airway remodeling in patients with stable COPD

Objective:To study the effect of adjuvant N-acetylcysteine (NAC) effervescent tablets therapy on cardiopulmonary function and airway remodeling in patients with stable chronic obstructive pulmonary disease (COPD).Methods: Patients with stable COPD treated in Zigong Third People's Hospital and West China Hospital, Sichuan University between May 2014 and October 2016 were selected and randomly divided into two groups, NAC group received N-acetylcysteine effervescent tablets combined with routine treatment, and control group received routine treatment. Before treatment as well as 2 weeks and 4 weeks after treatment, oxidative stress indexes and airway remodeling indexes in serum as well as inflammatory response indexes in peripheral blood were determined.Results: MDA, PC, 8-OHdG, MMP2, MMP3 and MMP9 contents in serum as well as NLRP3, ASC, p38MAPK and TREM-1 mRNA expression levels in peripheral blood mononuclear cells of both groups of patients after treatment were significantly lower than those before treatment while TAC levels as well as TIMP1 and TIMP2 contents in serum were significantly higher than those before treatment, and MDA, PC, 8-OHdG, MMP2, MMP3 and MMP9 contents in serum a well as NLRP3, ASC, p38MAPK and TREM-1 mRNA expression levels in peripheral blood mononuclear cells of NAC group after treatment were significantly lower than those of control group while TAC levels as well as TIMP1 and TIMP2 contents in serum were significantly higher than those of control group.Conclusion:Adjuvant NAC effervescent tablets treatment of stable COPD can improve the effect of oxidative stress and inflammatory response on cardiopulmonary function, and inhibit the airway remodeling caused by protease activation.

Chemical constituents and pharmacological effects of durian shells in ASEAN countries:A review

Durio zibethnus is mainly distributed in Southeast Asia.Traditional Chinese medicine believes that durian shells have the effects of clearing heat and purging fire,nourishing yin and moisturizing dryness.Therefore,it is often used as a pharmaceutic food in the Chinese folk to assist treating diseases.At present,the chemical constituents isolated from durian shell include phenolic acids,phenolic glycosides,flavonoids,coumarins,triterpenes,simple glycosides and other compounds.Modern pharmacological studies show that durian shell has many pharmacological activities,such as antioxidant,antiinflammatory,regulation of glucose and lipid metabolism.The chemical composition and pharmacological effects of durian shells are summarized in order to provide references for the further research and application of durian shell.

Viscous Shock Wave to an Inflow Problem for Compressible Viscous Gas with Large Density Oscillations

This paper is concerned with the inflow problem for one-dimensional compressible Navier-Stokes equations. For such a problem, Huang, Matsumura, and Shi showed in [4] that there exists viscous shock wave solution to the inflow problem and both the boundary layer solution, the viscous shock wave, and their superposition are time-asymptotically nonlinear stable provided that both the initial perturbation and the boundary velocity are assumed to be sufficiently small. The main purpose of this paper is to show that similar stability results still hold for a class of large initial perturbation which can allow the initial density to have large oscillations. The proofs are given by an elementary energy method and our main idea is to use the smallness of the strength of the viscous shock wave and the boundary velocity to control the possible growth of the solutions induced by the nonlinearity of the compressible Navier-Stokes equations and the inflow boundary condition.The key point in our analysis is to deduce the desired uniform positive lower and upper bounds on the density.