Structure of Metastable States in Phase Transitions with High-Spin Low-Spin Degree of Freedom

Difference of degeneracy of the low-spin (LS) and high-spin (HS) states causes interesting entropy effects on spin-crossover phase transitions and charge transfer phase transitions in materials composed of the spin-crossover atoms. Mechanisms of the spin-crossover (SC) phase transitions have been studied by using Wajnflasz model, where the degeneracy of the spin states (HS or LS) is taken into account and cooperative natures of the spin-crossover phase transitions have been well described. Recently, a charge transfer (CT) phase transition due to electron hopping between LS and HS sites has been studied by using a generalized Wajnflasz model. In the both systems of SC and CT, the systems have a high temperature structure (HT) and a low temperature structure (LT), and the change between them can be a smooth crossover or a discontinuous first order phase transition depending on the parameters of the systems. Although apparently the standard SC system and the CT system are very different, it is shown that both models are equivalent under a certain transformation of variables. In both systems, the structure of metastable state at low temperatures is a matter of interest. We study temperature dependence of fraction of HT systematically in a unified model, and find several structures of equilibrium and metastable states of the model as functions of system parameters. In particular, we find a reentrant type metastable branch of HT in a low temperature region, which would play an important role to study the photo-irradiated processes of related materials.Comment: 19 pages, 11 figure

T2 relaxation times of the retrodiscal tissue in patients with temporomandibular joint disorders and in healthy volunteers: A comparative study

Objective. The aims of this study were to compare the temporomandibular joint (TMJ) retrodiscal tissue T2 relaxation times between patients with temporomandibular disorders (TMDs) and asymptomatic volunteers and to assess the diagnostic potential of this approach. Study Design. Patients with TMD (n = 173) and asymptomatic volunteers (n = 17) were examined by using a 1.5-T magnetic resonance scanner. The imaging protocol consisted of oblique sagittal, T2-weighted, 8-echo fast spin echo sequences in the closed mouth position. Retrodiscal tissue T2 relaxation times were obtained. Additionally, disc location and reduction, disc configuration, joint effusion, osteoarthritis, and bone edema or osteonecrosis were classified using MRI scans. The T2 relaxation times of each group were statistically compared. Results. Retrodiscal tissue T2 relaxation times were significantly longer in patient groups than in asymptomatic volunteers (P < .01). T2 relaxation times were significantly longer in all of the morphologic categories. The most important variables affecting retrodiscal tissue T2 relaxation times were disc configuration, joint effusion, and osteoarthritis. Conclusion. Retrodiscal tissue T2 relaxation times of patients with TMD were significantly longer than those of healthy volunteers. This finding may lead to the development of a diagnostic marker to aid in the early detection of TMDs

An anticorrosive magnesium/carbon nanotube composite

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in APPLIED PHYSICS LETTERS. 92(6):63105 (2008) and may be found at https://doi.org/10.1063/1.2842411 .ArticleAPPLIED PHYSICS LETTERS. 92(6):63105 (2008)journal articl

Magnetic-field-induced Luttinger liquid

It is shown that a strong magnetic field applied to a bulk metal induces a Luttinger-liquid phase. This phase is characterized by the zero-bias anomaly in tunneling: the tunneling conductance scales as a power-law of voltage or temperature. The tunneling exponent increases with the magnetic field as BlnB. The zero-bias anomaly is most pronounced for tunneling with the field applied perpendicular to the plane of the tunneling junction.Comment: a reference added, minor typos correcte

An anticorrosive magnesium/carbon nanotube composite

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in APPLIED PHYSICS LETTERS. 92(6):63105 (2008) and may be found at https://doi.org/10.1063/1.2842411 .ArticleAPPLIED PHYSICS LETTERS. 92(6):63105 (2008)journal articl

Collective resonant dynamics of the chiral spin soliton lattice in a monoaxial chiral magnetic crystal

The magnetic resonance properties of microsized monoaxial chiral crystals of CrNb3S6 are investigated. We observed that the resonance of the chiral soliton lattice is sensitive to the polarization of the driving microwave field. When the microwave field is parallel to the helical axis, the resonance is symmetric with regards to the magnetic field direction. In contrast, asymmetric field dependence emerges when the microwave field is perpendicular to the helical axis. The robustness of the chiral magnetic order, due to topological protection, allows tuning the resonance frequency in ways hardly accessible using nanopatterned films

Inhibition of HIF-1α by the anticancer drug TAS106 enhances X-ray-induced apoptosis in vitro and in vivo

In a previous study, we showed that a novel anticancer drug, 1-(3-C-ethynyl-β-D-ribo-pentofuranosyl)cytosine (TAS106, ECyd) increased the antitumour efficacy of X-irradiation. However, its effects on hypoxic cells in tumours remain unclarified. Here, we show that TAS106 enhances the induction of apoptosis in X-irradiated human gastric adenocarcinoma MKN45 and MKN28 cells under hypoxia in vitro. At the same time, the accumulation of HIF-1α observed under hypoxia was shown to be decreased to the level of normoxia in the presence of 0.1 μM TAS106. To study the function of HIF-1α protein in apoptosis of hypoxic cells, we employed an HIF-1α reductive approach using its specific antisense oligodeoxynucleotide. The reduction of HIF-1α gene expression dramatically enhanced X-ray-induced apoptosis in hypoxic cells. In in vivo experiments in which MKN45 cells were transplanted into severe combined immunodeficient (SCID) mice, TAS106 (0.5 mg kg−1) suppressed HIF-1α expression and subsequently reduced the area of the hypoxic region in the tumour and enhanced the induction of apoptosis in the hypoxic region when combined with 2 Gy of X-irradiation. These results suggest the possibility that TAS106 acts as a potent radiosensitiser through the inhibition of HIF-1α expression and can be a useful agent against radiotherapy-resistant hypoxic cells in solid tumours