No abstract

Recent studies have suggested that increased oxidative stress is a potential etiology in Parkinson's disease (PD). In this study, we investigated whether acupuncture regulates antioxidants in the striatum (ST) of a PD mouse model. Male C57BL/6 mice were administered 30 mg/kg of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intraperitoneally once a day for 5 days and given acupuncture stimulation at SI3 or GB34 (Yanglingquan) was for 12 consecutive days. Dopaminergic neuronal survival in the nigrostriatal pathway and DJ-1 expression in the ST was evaluated by immunostaining, and the activities of superoxide dismutase (SOD) and catalase (CAT) in the ST was by enzyme-linked immunosorbent assay. MPTP administration induced dopaminergic neuronal death in the nigrostriatal pathway, which was suppressed by acupuncture stimulation at GB34. MPTP administration also suppressed DJ-1 expression and SOD and CAT activities in the ST, which were restored by acupuncture stimulation at GB34. These results indicate that the neuroprotective effect of acupuncture stimulation is due to regulation of the antioxidants.

No abstract

Interface‐generated spin currents in ferromagnet (FM)/nonmagnet (NM) structures provide both in‐plane and out‐of‐plane spin–orbit torques (SOTs), enabling the field‐free switching of perpendicular magnetization of the other FM layer in magnetic trilayers. In this study, the NM thickness dependence of interface‐generated spin currents and associated SOTs in FM/Ti/CoFeB trilayers is investigated. In such magnetic trilayers, it is known that the in‐plane SOT results from the spin–orbit filtering of the interface‐generated spin current, while the out‐of‐plane SOT is due to the spin–orbit precession. These results show that the polarity of current‐induced magnetization switching under an in‐plane magnetic field reverses with increasing Ti thickness. This indicates that the sign of the in‐plane SOT depends on the current distribution between the bottom FM and Ti layers. On the other hand, field‐free switching occurs only for a Ti thickness of up to ≈4 nm, and the same polarity is retained, demonstrating that out‐of‐plane SOT is governed by the charge current flowing near the interface. These results suggest that field‐free switching efficiency can be enhanced by engineering the relative conductance of the FM/NM bilayers to constructively combine in‐plane and out‐of‐plane SOTs caused by interface‐generated spin currents.

We investigate the Pt thickness dependence of spin–orbit torques (SOTs) in Co/Pt layers grown on single crystalline SrTiO3 and LaAlO3 and amorphous SiO2 substrates. We measure the SOT-induced effective damping-like fields and spin Hall magnetoresistances of the Co/Pt (tPt) samples, where tPt varies from 0.5 to 5.5 nm. We find that the Co/Pt layers grown on the single crystalline substrates show weaker thickness dependence of the SOT than the samples on the SiO2 substrate, which cannot be explained by the conventional bulk spin Hall effect in the Pt layer. This indicates that there is a non-negligible interfacial SOT originating from the Pt/substrate interface, which is more pronounced for thinner Pt. These results provide a way to design SOT material structures with enhanced SOT efficiency by incorporating interfacial SOT.