Resonance of Domain Wall in a Ferromagnetic Nanostrip: Relation Between Distortion and Velocity

The resonance of the magnetic domain wall under the applied field amplifies its velocity compared to the one-dimensional model. To quantify the amplification, we define the distortion variation rate of the domain wall that can represent how fast and severely the wall shape is variated. Introducing that rate gives a way to bring the resonance into the one-dimensional domain wall dynamics model. We obtain the dissipated energy and domain wall velocity amplification by calculating the distortion variation rate. The relationship between velocity and distortion variation rate agrees well with micromagnetic simulation.Comment: 15 pages, 4 figure

Total Reflection and Negative Refraction of Dipole-Exchange Spin Waves at Magnetic Interfaces: Micromagnetic Modeling Study

We demonstrated that dipole-exchange spin waves traveling in geometrically restricted magnetic thin films satisfy the same laws of reflection and refraction as light waves. Moreover, we found for the first time novel wave behaviors of dipole-exchange spin waves such as total reflection and negative refraction. The total reflection in laterally inhomogeneous thin films composed of two different magnetic materials is associated with the forbidden modes of refracted dipole-exchange spin waves. The negative refraction occurs at a 90 degree domain-wall magnetic interface that is introduced by a cubic magnetic anisotropy in the media, through the anisotropic dispersion of dipole-exchange spin waves.Comment: 13 pages, 5 figure

Sulforaphane Increases Cyclin-Dependent Kinase Inhibitor, p21 Protein in Human Oral Carcinoma Cells and Nude Mouse Animal Model to Induce G2/M Cell Cycle Arrest

Previously, our group reported that sulforaphane (SFN), a naturally occurring chemopreventive agent from cruciferous vegetables, effectively inhibits the proliferation of KB and YD-10B human oral squamous carcinoma cells by causing apoptosis. In this study, treatment of 20 and 40 µM of SFN for 12 h caused a cell cycle arrest in the G2/M phase. Cell cycle arrest induced by SFN was associated with a significant increase in the p21 protein level and a decrease in cyclin B expression, but there was no change in the cyclin A protein level. In addition, SFN increased the p21 promoter activity significantly. Furthermore, SFN induced p21 protein expression in a nude mouse xenograft model suggesting that SFN is a potent inducer of the p21 protein in human oral squamous carcinoma cells. These findings show that SFN is a promising candidate for molecular-targeting chemotherapy against human oral squamous cell carcinoma

Characteristics of Calcium Phosphate Films Prepared by Pulsed Laser Deposition under Various Water Vapor Pressures

Calcium phosphate films were prepared by using a pulsed laser deposition (PLD) technique with a KrF excimer laser (248 nm, 2 J/cm²) under a wide range of H2O pressures at a substrate temperature of 600℃. Sintered hydroxyapatite (HA) was used as the target. The background H2O pressure during deposition critically affected the density and the composition of the deposited films. With increasing H2O pressure, the growth rate increased, and the mass deposited was almost constant. Consequently, the density gradually decreased with H2O pressure, resulting in a porous microstructure under 0.37 Torr. The Ca/P ratio of the film decreased with H2O pressure, and the crystal structure of the deposited film changed in accordance with the Ca/P ratio. The observed peaks were from hydroxyapatite (Ca/P = 1.67) for H2O pressures above 0.13 Torr, and the peaks from high Ca/P phases, such as tetracalcium phosphate [Ca4O(PO4)2, Ca/P = 2] and CaO (Ca/P = ∞), were observed for the film deposited at 0.02 Torr. A high-density hydroxyapatite film with a high degree of crystallinity was obtained under a H2O pressure of 0.25 Torr

Influences of Ambient Gases on the Structure and the Composition of Calcium Phosphate Films Prepared by Pulsed Laser Deposition

Calcium phosphate films were prepared by using a pulsed KrF-laser deposition (PLD) method with a hydroxyapatite target in various ambient gases, such as Ar, O2 and H2O. The influence of the ambient gas on the properties of the deposited films was investigated. The chamber pressure and the substrate temperature were fixed at 0.25 Torr and 600℃, respectively. Calcium-rich amorphous calcium phosphate films were deposited with a low density in Ar due to the preferential resputtering of phosphorus from the growing film. In an O2 ambient, the density and the Ca/P ratio of the films were similar to those of the target. However, the deposited film was amorphous calcium phosphate and did not contain OH− groups. Polycrystalline hydroxyapatite films can be deposited in a H2O ambient because a sufficient supply of OH− groups from the ambient gas is essential for the growth of a hydroxyapatite film

Isolation and characterization of differentially expressed genes in the mycelium and fruit body of Pleurotus ostreatus

The fruiting body of one of the most widely cultivated mushrooms, the oyster mushroom (Pleurotus ostreatus) is highly interesting, both commercially and scientifically. In the present study, we performed comparative proteomic profiling of P. ostreatus at two unique developmental stages; mycelium and fruit body, using two-dimensional gel electrophoresis (2-DE). Seven hundred fourteen (714) spots were detected and 29 spots (showing a high level of difference in their expressions) were identified by tandem mass spectrometry and basic local alignment search tool (BLAST) searching of an expressed sequence tag (EST) database of P. ostreatus. Among them, six proteins (putative fatty acid oxygenase, heat shock sks2, PriA homologue, Ap-1 like transcription factor YAP7, mung bean seed albumin, and C2H2 Zinc finger domain protein) and one protein (peroxisomal biogenesis factor 6) showed increased expression levels at the fruiting process and the mycelial stage, respectively. Through reverse transcriptase-polymerase chain reaction analysis, priA homologue and AP-1 like transcription factor yap7 showed gradually increased expression from mycelia to fruit body, whereas putative fatty acid oxygenase and heat shock protein sks2 were expressed only in the fruit body. These results provide useful information for future studies of mushroom development of P. ostreatus.Keywords: Developmental stage, mushroom fruiting, Pleurotus ostreatus, protein, two-dimensional gel electrophoresisAfrican Journal of Biotechnology Vol. 12(24), pp. 3790-379

FBXW7-mediated ERK3 degradation regulates the proliferation of lung cancer cells

Extracellular signal-regulated kinase 3 (ERK3) is an atypical member of the mitogen-activated protein kinase (MAPK) family, members of which play essential roles in diverse cellular processes during carcinogenesis, including cell proliferation, differentiation, migration, and invasion. Unlike other MAPKs, ERK3 is an unstable protein with a short half-life. Although deubiquitination of ERK3 has been suggested to regulate the activity, its ubiquitination has not been described in the literature. Here, we report that FBXW7 (F-box and WD repeat domain-containing 7) acts as a ubiquitination E3 ligase for ERK3. Mammalian two-hybrid assay and immunoprecipitation results demonstrated that ERK3 is a novel binding partner of FBXW7. Furthermore, complex formation between ERK3 and the S-phase kinase-associated protein 1 (SKP1)-cullin 1-F-box protein (SCF) E3 ligase resulted in the destabilization of ERK3 via a ubiquitination-mediated proteasomal degradation pathway, and FBXW7 depletion restored ERK3 protein levels by inhibiting this ubiquitination. The interaction between ERK3 and FBXW7 was driven by binding between the C34D of ERK3, especially at Thr417 and Thr421, and the WD40 domain of FBXW7. A double mutant of ERK3 (Thr417 and Thr421 to alanine) abrogated FBXW7-mediated ubiquitination. Importantly, ERK3 knockdown inhibited the proliferation of lung cancer cells by regulating the G1/S-phase transition of the cell cycle. These results show that FBXW7-mediated ERK3 destabilization suppresses lung cancer cell proliferation in vitro