Tunable pure spin currents in a triple-quantum-dot ring

Electron transport properties in a triple-quantum-dot ring with three terminals are theoretically studied. By introducing local Rashba spin-orbit interaction on an individual quantum dot, we calculate the charge and spin currents in one lead. We find that a pure spin current appears in the absence of a magnetic field. The polarization direction of the spin current can be inverted by altering the bias voltage. In addition, by tuning the magnetic field strength, the charge and spin currents reach their respective peaks alternately.Comment: 5 pages, 2 Figure

Rashba-induced transverse pure spin currents in a four-terminal quantum dot ring

By applying a local Rashba spin-orbit interaction on an individual quantum dot of a four-terminal four-quantum-dot ring and introducing a finite bias between the longitudinal terminals, we theoretically investigate the charge and spin currents in the transverse terminals. It is found that when the quantum dot levels are separate from the chemical potentials of the transverse terminals, notable pure spin currents appear in the transverse terminals with the same amplitude and opposite polarization directions. Besides, the polarization directions of such pure spin currents can be inverted by altering structure parameters, i.e., the magnetic flux, the bias voltage, and the values of quantum dot levels with respect to the chemical potentials of the transverse terminals.Comment: 4 pages, 3 figures, Submitted to nanotechnolog

Detection of spin bias in four-terminal quantum-dot ring

In this work, we show that in a four-quantum-dot ring, via introducing a local Rashba spin-orbit interaction the spin bias in the transverse terminals can be detected by observing the charge currents in the longitudinal probes. It is found that due to the Rashba interaction, the quantum interference in this system becomes spin-dependent and the opposite-spin currents induced by the spin bias can present different magnitudes, so charge currents emerge. Besides, the charge currents rely on both the magnitude and spin polarization direction of the spin bias. It is believed that this method provides an electrical but practical scheme to detect the spin bias (or the spin current).Comment: 6 pages, 5 figure

Vitamin E Inhibits Osteoclastogenesis in Protecting Osteoporosis

The most common orthopedic condition affecting senior adults is osteoporosis, which is defined by a decrease in bone mass and strength as well as microstructural degradation that leads to fragility fractures. Bone remodeling is a well-planned, ongoing process that replaces deteriorated, old bone with new, healthy bone. Bone resorption and bone creation work together during the cycle of bone remodeling to preserve the bone’s volume and microarchitecture. The only bone-resorbing cells in the human body, mononuclear preosteoclasts fuse to form osteoclasts, are multinucleated cells. In numerous animal models or epidemiological studies, vitamin E’s anti-osteoporotic characteristics have been extensively described. This review aims to summarize recent developments in vitamin E’s molecular features as a bone-protective agent. In RANKL/RANK/OPG signaling pathway, vitamin E inhibits synthesis of RANKL, stimulation of c-Fos, and increase level of OPG. Vitamin E also inhibits inflammatory cytokines, such as TNF-α, IL-1, IL-6, IL-27, and MCP-1, negative regulating the JAK–STAT, NF-κB, MAPK signaling pathways. Additionally, vitamin E decreases malondialdehyde and increases superoxide dismutase, GPx and heme oxygenase-1, in suppressing osteoclasts. In this article, we aim to give readers the most recent information on the molecular pathways that vitamin E uses to enhance bone health