Endothelin suppresses cell migration via the JNK signaling pathway in a manner dependent upon Src kinase, Rac1, and Cdc42

AbstractCell migration is a complex phenomenon that is stimulated by chemoattractive factors such as chemokines, a family of ligands for G protein-coupled receptors (GPCRs). In contrast, factors that suppress cell migration, and the mechanism of their action, remain largely unknown. In this study, we show that endothelin, a GPCR ligand, inhibits cell motility in a manner dependent upon signaling through the c-Jun N-terminal kinase (JNK) pathway. We further demonstrate that this effect is dependent upon Src kinase and small GTPases Rac1 and Cdc42. These findings provide new insight into GPCR-mediated regulation of cell migration

Magnetic response of random lasing modes in a ZnO nanoparticle film deposited on a NiFe thin film

This study experimentally demonstrates lasing mode switching within a ZnO nanoparticle film coated onto a magnetic thin film of NiFe alloy. When a neodymium magnet is brought close to or moved away from the film, switching behavior is observed in the lasing modes, although such change is not induced in a ZnO nanoparticle film on a glass substrate. Our results suggest that the observed changes in lasing modes are because of a magneto-optical effect at the surface of the NiFe thin film. The magneto-optical effect would be enhanced by localized fields near the surface, inducing suppression or enhancement of the lasing modes in response to the surrounding environments, and accounting for the lasing mode switching

Evaluation of demolding force for glass-imprint process

Demolding behavior of oxide glasses from molds was experimentally analyzed using a specially developed molding set up equipped with highly sensitive load cell and servomotor. The demolding point and the demolding force were apt to increase with the tensile force applied to the pressing axis, and also to the cooling rate. Especially the demolding force was strongly affected by the cooling rate when the demolding point was located near the glass transition temperature region. These results offer a useful direction for highly accurate glass-molding and glass-imprint processes. (C) 2013 Elsevier B.V. All rights reserved

Wavelength-dependent magnetic transitions of self-organized iron-aluminum stripes induced by pulsed laser irradiation

We investigate the laser wavelength dependence of structural and magnetic transitions on the surface of an iron-aluminum (FeAl) alloy induced by nanosecond pulsed laser irradiation. The formation of self-organized FeAl stripes with a wavelength-dependent period is observed in a local area on the (111)-oriented plane. Focused magneto-optical Kerr effect measurements reveal that the coercivity reaches up to 1.2 kOe with increasing the magnetic field rotation angle, which is estimated from the stripe direction, in FeAl stripes irradiated at 355 nm, and its magnetization reversal can be explained by the domain-wall motion model. On the other hand, the magnetization reversal agrees with the Stoner-Wohlfarth model in FeAl stripes irradiated at 1064 nm. This magnetic transition originates from the B2-to-A2 phase transition in stripe structures and bulk regions. These results indicate that the magnetic transition from the incoherent to coherent mode as well as the structural transformation of stripe patterns can be controlled by the incident laser wavelength. (C) 2015 AIP Publishing LLC

A Novel Technique for Controlling Anisotropic Ion Diffusion : Bulk Single-Crystalline Metallic Silicon Clathrate

Na-free Si clathrates consisting only of Si cages are an allotrope of diamond-structured Si. This material is promising for various device applications, such as next-generation photovoltaics. The probable technique for synthesizing Na-free Si clathrates is to extract Na+ from the Si cages of Na24Si136. Vacuum annealing is presently a well-known conventional and effective approach for extracting Na. However, this study demonstrates that Na+ cannot be extracted from the surface of a single-crystalline type-II metallic Si clathrate (Na24Si136) in areas deeper than 150 mu m. Therefore, a novel method is developed to control anisotropic ion diffusion: this is effective for various compounds with a large difference in the bonding strength between their constituent elements, such as Na24Si136 composed of covalent Si cages and weakly trapped Na+. By skillfully exploiting the difference in the chemical potentials as a driving force, Na+ is homogeneously extracted regardless of the size of the single crystal while maintaining high crystallinity. Additionally, the proposed point defect model is evaluated via density functional theory, and the migration of Na+ between the Si cages is explained. It is expected that the developed experimental and computational techniques would significantly advance material design for synthesizing thermodynamically metastable materials

Co thickness dependence of structural and magnetic properties in spin quantum cross devices utilizing stray magnetic fields

We investigate the Co thickness dependence of the structural and magnetic properties of Co thin-film electrodes sandwiched between borate glasses in spin quantum cross (SQC) devices that utilize stray magnetic fields. We also calculate the Co thickness dependence of the stray field between the two edges of Co thin-film electrodes in SQC devices using micromagnetic simulation. The surface roughness of Co thin films with a thickness of less than 20 nm on borate glasses is shown to be as small as 0.18 nm, at the same scanning scale as the Co film thickness, and the squareness of the hysteresis loop is shown to be as large as 0.96-1.0. As a result of the establishment of polishing techniques for Co thin-film electrodes sandwiched between borate glasses, we successfully demonstrate the formation of smooth Co edges and the generation of stray magnetic fields from Co edges. Theoretical calculation reveals that a strong stray field beyond 6 kOe is generated when the Co thickness is greater than 10 nm at a junction gap distance of 5 nm. From these experimental and calculation results, it can be concluded that SQC devices with a Co thickness of 10-20 nm can be expected to function as spin-filter devices