First-principles insights into hydrogen trapping in interstitial-vacancy complexes in vanadium carbide.

Hydrogen trapping is a key factor in designing advanced vanadium alloys and steels, where the influence of carbon vacancies is still elusive. Herein we have investigated the effect of carbon vacancies on the hydrogen trapping of defect-complexes in vanadium carbide using first-principles calculations. When a carbon vacancy is present, the second nearest neighboring trigonal interstitial is a stable hydrogen trapping site. A C vacancy enhances the hydrogen trapping ability by reducing the chemical and mechanical effects on H atom solution energy. Electronic structure analysis shows that C vacancies increase the charge density and the Bader atomic volume, leading to a lower H atom solution energy. The strength of the V-H bond is predominant in determining the hydrogen trapping ability in the presence of a C vacancy, in contrast to that of a C-H bond when the C vacancy is absent.

Correction: First-principles insights into hydrogen trapping in interstitial-vacancy complexes in vanadium carbide.

Correction for 'First-principles insights into hydrogen trapping in interstitial-vacancy complexes in vanadium carbide' by Shuai Tang et al., Phys. Chem. Chem. Phys., 2022, DOI: https://doi.org/10.1039/d2cp02425j.

Leonurine hydrochloride induces apoptosis of H292 lung cancer cell by a mitochondria-dependent pathway.

CONTEXT: Leonurine hydrochloride (LH), a major alkaloid compound extracted from Leonurus japonicas Houtt. (Labiatae), is considered to have antitumor roles. OBJECTIVE: This study investigated its effects on human non-small cell lung cancer (NSCLC) H292 cells and illustrated the possible mechanism involved. MATERIALS AND METHODS: After treatment with different concentrations of LH (0, 10, 25, and 50 µmol/L) for 6, 12, 24, 48, and 72 h, the cell viability was assessed by the MTT assay. After exposed to different doses of LH for 24 h, cell-cycle distribution, cell apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) were monitored by flow cytometry. RT-PCR and western blot were used to detect the expression of apoptosis-related genes. RESULTS: LH significantly inhibited the proliferation of H292 cells in a time- and dose-dependent manner, and induced G0/G1 cell-cycle arrest. Coincidentally, LH treatment at a dose of 10, 25, and 50 µmol/L for 24 h increased apoptotic ratio from 4.9 ± 0.43% to 11.5 ± 1.12%, 19.3 ± 1.16%, and 61.3 ± 6.69%, respectively. The inhibition effect of LH on H292 cells was associated with the loss of MMP and the generation of ROS. The phosphorylation level of p38 was increased and Akt phosphorylation was reduced by LH treatment. Furthermore, LH treatment increased the expression levels of caspase-3, caspase-9 and Bax/Bcl-2. CONCLUSIONS: LH inhibits the proliferation and induces the apoptosis of H292 cells in a mitochondria-dependent pathway, and the specific mechanism need to be further explored.