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ABSTRACT The occurrence of hydrogen embrittlement often leads to significant fracturing in materials. Thus, a comprehensive understanding of the interactions of hydrogen and its effects on material properties is essential. In this study, first‐principle calculations based on density functional theory are conducted to investigate the adsorption and diffusion characteristics of hydrogen at the Ni/Ni3Al(γ/γ') interface of a Ni‐based single‐crystal superalloy. The results show that hydrogen can stably adsorb onto the γ/γ′ interface, nearby octahedral interstitial sites, and tetrahedral interstitial sites in the γ‐phase. Analysis of the density of states and charge density confirms that the hydrogen atoms formed covalent bonds and ionic bonds with nearby Al atoms. A transition state structure search based on linear synchronous transit (LST) and quadratic synchronous transit (QST) models is utilized to calculate the diffusion paths and energy barriers of the hydrogen atoms between the stable adsorption sites near the interface. In addition, the permeation characteristics of hydrogen atoms at the interface are analyzed. Furthermore, it is confirmed that hydrogen atoms entering the matrix from the interface preferentially occupy the positions of the regular octahedral interstitial sites, diffuse towards adjacent regular 6Ni octahedral interstitial sites through the inclined octahedral interstitial sites between the atomic layers, and converge at the interface. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the effect of anesthetic drugs on the expression of circadian gene Clock and Bmal1 in the brain of New Zealand rabbits, and to explore their change pattern., Methods: A total of 90 New Zealand rabbits were randomly divided into 5 groups ( n =18 in each group): A normal saline group (1 mL/h saline, group S), a propofol group [600 µg/(kg·min -1 ) propofol, 1 mL/h, group P], a 10% lipid group (1 mL/h lipid, group F), a dexmedetomidine group [1 µg/(kg·min -1 ) dexmedetomidine, 1 mL/h, group D), a sevoflurane (SEV) group (2.5% SEV, SEV group). Inhaled and intravenous anesthetic drugs were stopped after 24 h. Experimental animals were killed at 0, 24, and 72 h after anesthesia, and their brain tissues were isolated. Western blotting was performed to measure the Clock and Bmal1 protein expression in the brain of rabbits., Results: At 0 and 24 h after anesthesia, compared with the group S, the levels of Clock and Bmal1 proteins were decreased significantly in the group P, the group D, and the group SEV (all P <0.05). At 72 h after anesthesia, compared with the group S, the levels of Clock and Bmal1 proteins showed no significant changes in the group P, the group D, and the SEV group (all P >0.05). Compared with the group S, the levels of Clock and Bmal1 proteins at all time points showed no significant changes in the group F (all P >0.05)., Conclusions: Anesthetic SEV, propofol, and dexmedetomidine can inhibit the expression of clock gene Clock and Bmal1 protein in the brain fissues of the New Zealand rabbits, and the suppression effect continues for at least 24 h after anesthesia, whereas the suppression decreases significantly at 72 h after anesthesia.

Acute lung injury (ALI) induced by liver transplantation is detrimental to patient survival, and therapeutic strategies remain limited. Thus, the protective effects of propofol, a commonly used anesthetic with antioxidative and anti‑inflammatory properties, were investigated in the present study on ALI induced by orthotopic autologous liver transplantation (OALT). The protective mechanism of propofol was determined to be associated with the inhibition of NADPH oxidase, by comparing its effects with the positive controls apocynin (AP; an NADPH oxidase inhibitor) and N‑acegysteine (NAC; a scavenger of reactive oxygen species). The results demonstrated that two proteins (p47phox and gp91phox) of the NADPH oxidase system presented increased expression in rats with ALI induced by OALT, thus leading to increased activation of the oxidative stress and inflammatory reactions. Preconditioning with NAC or AP eliminated this increase, suggesting that antioxidative treatment, particularly with inhibitors of NADPH oxidase, is a promising protective strategy against ALI induced by OALT. Propofol preconditioning at a high (100 mg/kg) or low (50 mg/kg) dose promoted similar protective effects, with the high‑dose propofol producing a more marked effect than the low dose. The results suggested that propofol may protect against ALI induced by OALT, the mechanism of which may involve a reduced oxidative stress and inflammatory reaction mediated by NADPH oxidase inhibition.