EGF-MAPK-NF-kB cascade signaling pathway: Possible mechanism of particulate matter (PM) 2.5 -induced lung inflammatory responses

Abstract

Different cubic Co-based Heusler alloys — Co 2FeAl (CFA), Co 2FeSi (CFS), Co 2MnAl (CMA), and Co 2MnSi (CMS) — were grown epitaxially on tetragonal Heusler-like D0 22–MnGa at different annealing temperatures (Ta) in the form of Heusler (20 nm)/MnGa (30 nm) bilayers. The CMA/MnGa bilayer showed the largest critical temperature (450 ∘ C), indicating good structural stability against interdiffusion. The experimental results showed an easier interdiffusion of the Fe and Si elements than of Mn and Al. An inverted hysteresis loop was observed in a polar magneto-optical Kerr effect (P-MOKE) measurement for the CFS/MnGa, CMA/MnGa, and CMS/MnGa bilayers. This is one piece of evidence for the existence of the antiferromagnetic (AFM) interfacial exchange coupling (J ex). We evaluated J ex for the Heusler/MnGa bilayers annealed at different temperatures. J ex changed from ferromagnetic (FM) to AFM after annealing at 300 ∘ C for the CFA/MnGa bilayer. Other bilayers showed only AFM coupling. The strongest J ex value of approximately − 3.2 erg/cm 2 was obtained for the CMS/MnGa bilayer annealed at 400 ∘ C. It was found that the tendency of the Mn and Si elements to make AFM J ex in the Heusler/MnGa bilayers interfaces is larger than that of Fe and Al.