Hydrogen solution in high-entropy alloys.

High-entropy alloys (HEAs) have been reported to have superior ability in hydrogen (H) storage and strong resistance to H embrittlement. These exceptional properties are directly related to the H solution in the HEAs. However, the diversity of atomic environments in the HEAs complicate the calculation of the H solution energy. With regard to this, we clarified an origin causing the variety of solution energy from the viewpoint of chemical and elastic interactions of H with the host atoms. Combining the semi-empirical atom potential and first-principles calculations regarding H in FeCrCoNi, NbMoTaW, and FeCuCrMnMo, we found that the elastic interaction presents a visibly linear relationship with the volume expansion caused by H insertion. By contrast, the chemical interaction shows a non-linear relationship with the volume of the interstitial polyhedron. A universal model was then established to generalize the solution energy of H. This model can expeditiously assess the H distribution and provide insight into evolution of the microstructure in HEAs.

Peripheral blood dendritic cells and vascular endothelial growth factor in oral squamous cell carcinoma: correlation analysis and in vitro study.

Vascular endothelial growth factor (VEGF) may cause functional deficiency in dendritic cells (DCs) in vitro. The roles of peripheral blood dendritic cells (PBDCs) and VEGF in patients with oral squamous cell carcinoma (OSCC) are not well understood. The authors analysed the correlation between VEGF and PBDC in 81 OSCC patients. They assessed the effect of VEGF on DC function in vitro. VEGF levels were significantly increased in OSCC patients compared with control subjects (P < 0.05), but PBDC levels were significantly lower (P < 0.05). VEGF expression in TNM I-II (67%) and T1-T2 (74%) was significantly lower, compared with TNM III-IV (88%, P < 0.05) and T3-T4 (89%, P < 0.05). Increased VEGF expression in primary tumours was significantly correlated with elevated serum VEGF levels, but reduced PBDC levels. In vitro cultured DC exposed to VEGF showed significantly decreased expression of functional proteins, enhanced endocytosis activity, and elicited weaker proliferation of T cells, compared with that of free VEGF (P < 0.01). These findings suggest that decreased PBDC and elevated VEGF occur in OSCC patients. Higher VEGF levels may affect precursor cells, resulting in decreased numbers of functional DC.