RESUMEN
Interfacial magnetic interactions between different elements are the origin of various spin-transport phenomena in multi-elemental magnetic systems. We investigate the coupling between the magnetic moments of the rare-earth, transition-metal, and heavy-metal elements across the interface in a GdFeCo/Pt thin film, an archetype system to investigate ferrimagnetic spintronics. The Pt magnetic moments induced by the antiferromagnetically aligned FeCo and Gd moments are measured using element-resolved x-ray measurements. It is revealed that the proximity-induced Pt magnetic moments are always aligned parallel to the FeCo magnetic moments, even below the ferrimagnetic compensation temperature where FeCo has a smaller moment than Gd. This is understood by a theoretical model showing distinct effects of the rare-earth Gd 4f and transition-metal FeCo 3d magnetic moments on the Pt electronic states. In particular, the Gd and FeCo work in-phase to align the Pt moment in the same direction, despite their antiferromagnetic configuration. The unexpected additive roles of the two antiferromagnetically coupled elements exemplify the importance of detailed interactions among the constituent elements in understanding magnetic and spintronic properties of thin film systems.
RESUMEN
BACKGROUND/OBJECTIVES: The primary objective of the treatment of diabetes mellitus is the attainment of glycemic control. Hyperglycemia increases oxidative stress which contributes to the progression of diabetic complications. Thus, the purpose of this study was to investigate the hypoglycemic and antioxidant effects of Daraesoon (Actinidia arguta shoot) in animal models of diabetes mellitus. MATERIALS/METHODS: Rats with streptozotocin-induced diabetes received an oral administration of a starch solution (1 g/kg) either with or without a 70% ethanol extract of Daraesoon (400 mg/kg) or acarbose (40 mg/kg) after an overnight fast and their postprandial blood glucose levels were measured. Five-week-old C57BL/6J mice were fed either a basal or high-fat/high-sucrose (HFHS) diet with or without Daraesoon extract (0.4%) or acarbose (0.04%) for 12 weeks after 1 week of adaptation to determine the effects of the chronic consumption of Daraesoon on fasting hyperglycemia and antioxidant status. RESULTS: Compared to the control group, rats that received Daraesoon extract (400 mg/kg) or acarbose (40 mg/kg) exhibited a significant reduction in the area under the postprandial glucose response curve after the oral ingestion of starch. Additionally, the long-term consumption of Daraesoon extract or acarbose significantly decreased serum glucose and insulin levels as well as small intestinal maltase activity in HFHS-fed mice. Furthermore, the consumption of Daraesoon extract significantly reduced thiobarbituric acid reactive substances and increased glutathione levels in the livers of HFHS-fed mice compared to HFHS-fed mice that did not ingest Daraesoon. CONCLUSIONS: Daraesoon effectively suppressed postprandial hyperglycemia via the inhibition of α-glucosidase in STZ-induced diabetic rats. Chronic consumption of Daraesoon alleviated fasting hyperglycemia and oxidative stress in mice fed a HFHS diet.