Hydrogen Embrittlement and Improved Resistance of Al Addition in Twinning-Induced Plasticity Steel: First-Principles Study.

Understanding the mechanism of hydrogen embrittlement (HE) of austenitic steels and developing an effective strategy to improve resistance to HE are of great concern but challenging. In this work, first-principles studies were performed to investigate the HE mechanism and the improved resistance of Al-containing austenite to HE. Our results demonstrate that interstitial hydrogen atoms have different site preferences in Al-free and Al-containing austenites. The calculated binding energies and diffusion barriers of interstitial hydrogen atoms in Al-containing austenite are remarkably higher than those in Al-free austenite, indicating that the presence of Al is more favorable for reducing hydrogen mobility. In Al-free austenite, interstitial hydrogen atoms caused a remarkable increase in lattice compressive stress and a distinct decrease in bulk, shear, and Young's moduli. Whereas in Al-containing austenite, the lattice compressive stress and the mechanical deterioration induced by interstitial hydrogen atoms were effectively suppressed.

[Clinical Studies of Abdominal Acupuncture Combined with Warm Needling on Knee Osteoarthritis].

OBJECTIVE: To explore the clinical effects of abdominal acupuncture combined with warm needling on knee osteoarthritis (KOA). METHODS: Eighty-six patients with KOA were divided into a treatment group and a control group according to the digital random table, 43 cases in each one. In the treatment group, patients were treated with abdominal acupuncture at Zhongwan (CV 12), Guanyuan (CV 4) and Huaroumen (ST 24), Wailing (ST 26) and Xiafengshidian (Extra) on the affected side, as well as warm needling at Neixiyan (EX-LE 4), Dubi (ST 35), Heding (EX-LE 2), Liangqiu (ST 34) and Xuehai (SP 10) of the affected side. In the control group, warm needling was given. All the patients were treated 5 times a week for 4 weeks. Each dimension score of Western Ontario and McMaster University (WOMAC) osteoarthritis index scale and health survey 36-item short form (SF-36) of the two groups was compared before and after treatment. Enzyme-linked immunosorbent assay was applied to test serum vascular endothelial growth factor (VEGF) and angiopoietin-1(Ang-1). RESULTS: Compared with those before treatment, the scores of pain, stiffness, joint function of WOMAC scale and serum VEGF, Ang-1 of the two groups were lower after treatment (all P<0.01), and each dimension score of SF-36 scale increased significantly (all P<0.01). Each dimension score of WOMAC scale and serum VEGF, Ang-1 in the treatment group were lower than those in the control group after treatment (all P<0.01), and each score of SF-36 was higher (all P<0.01). The total effective rate of 93.0% (40/43) in the treatment group was higher than 74.4% (32/43) in the control group (P<0.05). CONCLUSIONS: Abdominal acupuncture combined with warm needling can effectively alleviate pain and stiffness, improve the function of knee joint and quality of life, with definite effect for KOA. The mechanism may be related to the decreasing of serum VEGF and Ang-1.