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AerMet 100 steel is a new type of double-hardened high-strength steel, which is often used as landing gear material in amphibious aircraft. In the present paper, the corrosion fatigue behavior and mechanism of AerMet 100 high-strength steel in a 3.5% NaCl solution was studied by stress-controlled fatigue tests and a series of subsequent characterizations of the fracture surface, microstructure, and cracks. The results indicated that the fatigue life of AerMet 100 high-strength steel decreased with a decrease in the stress level in a 3.5% NaCl solution, satisfying the relationship lgN = −2.69 × 10−3 σ + 6.49. The corrosion fatigue crack usually initiated from the corrosion pit and propagated across the martensitic flat noodles. Meanwhile, the corrosion fatigue crack tip was filled with Cr2O3, Fe2O3, and amorphous material; it propagated in the transgranular mode by a slip dissolution mechanism. This study provides some engineering significant for the fatigue performance of AerMet 100 steel in a 3.5% NaCl solution. [ABSTRACT FROM AUTHOR]

Objective To observe the clinical efficacy of teicoplanin combined with levocarnitine in treatment of methicillin-resistant Staphylococcus aureus (MRSA) infective endocarditis (IE). Methods A total of 84 patients diagnosed with IE caused by MRSA admitted to our hospital from March 2018 to February 2019 were perspectively recruited, and then randomly divided into control group (teicoplanin and placebo) and combined treatment group (teicoplanin and levocarnitine), 42 cases in each group. Cardiac function indexes, including stroke output (SV), cardiac output (CO) and left ventricular ejection fraction (LVEF) were observed before and after treatment. The clinical efficacy and bacterial clearance were evaluated and compared between the 2 groups. The levels of hypersensitivity C-reaction protein (hs-CRP) and procalcitonin (PCT), white blood cell count (WBC), and erythrocyte sedimentation rate (ESR) in the serum of the 2 groups before and after treatment were compared. Adverse reactions during treatment were counted and compared. Results There were no significant differences in cardiac function indexes between the 2 groups before treatment (P>0.05). While, SV, CO and LVEF were increased after treatment in both groups, and the above values in the combined group were significantly higher than those of the control group (P < 0.05). Statistical difference was seen in the distribution of efficacy grade between the 2 groups (P < 0.05), and the combination group had notably higher total effective rate (95.24% vs 80.95%), clearance rate (92.86% vs 76.19%) and total clearance rate (97.62% vs 83.33%) when compared with the control group (all P < 0.05). There were no significant differences in serum hs-CRP and PCT levels and WBC and ESR before treatment (P>0.05). The indexes were decreased after treatment, with those in the combined group more significant (all P < 0.05). No significant difference was found in the incidence of total adverse reactions between the 2 groups (P>0.05). Conclusion Teicoplanin combined with L-carnitine is safe and reliable, and can effectively improve the cardiac function, promote bacterial clearance rate, and effectively control infection in IE patients induced by MRSA.

Abstract Background Little research has focused on the relationship between health insurance and mental health in the community. The objective of this study is to determine how the basic health insurance system influences depression in Northwest China. Methods Participants were selected from 32 communities in two northwestern Chinese cities through a three-stage random sampling. Three waves of interviews were completed in April 2006, December 2006, and January 2008. The baseline survey was completed by 4,079 participants. Subsequently, 2,220 participants completed the first follow-up, and 1,888 completed the second follow-up. Depression symptoms were measured by the Center for Epidemiologic Studies Depression Scale (CES-D). Results A total of 40.0% of participants had at least one form of health insurance. The percentages of participants with severe depressive symptoms in the three waves were 21.7%, 22.0%, and 17.6%. Depressive symptoms were found to be more severe among participants without health insurance in the follow-up surveys. After adjusting for confounders, participants without health insurance were found to experience a higher risk of developing severe depressive symptoms than participants with health insurance (7 months: OR, 1.40; 95% CI, 1.09-1.82; p = 0.01; 20 months: OR, 1.89; 95% CI, 1.37-2.61; p Conclusion A lack of basic health insurance can dramatically increase the risk of depression based on northwestern Chinese community samples.