160 research outputs found
Involvement of oxidative stress and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) in inflammatory bowel disease
The pathophysiology of inflammatory bowel disease involves excessive immune effects of inflammatory cells against gut microbes. In genetically predisposed individuals, these effects are considered to contribute to the initiation and perpetuation of mucosal injury. Oxidative stress is a fundamental tissue-destructive mechanisms that can occur due to the reactive oxygen species and reactive nitrogen metabolites which are released in abundance from numerous inflammatory cells that have extravasated from lymphatics and blood vessels to the lamina propria. This extravasation is mediated by interactions between adhesion molecules including mucosal addressin cell adhesion molecule-1 and vascular cell adhesion molecule-1 on the surface of lymphocytes or neutrophils and their ligands on endothelial cells. Thus, reactive oxygen species and adhesion molecules play an important role in the development of inflammatory bowel disease. The present review focuses on the involvement of oxidative stress and adhesion molecules, in particular mucosal addressin cell adhesion molecule-1, in inflammatory bowel disease
High-field magnetization and magnetic phase transition in CeOs2Al10
We have studied the magnetization of CeOs2Al10 in high magnetic fields up to
55 T for H // a and constructed the magnetic phase diagram for H // a. The
magnetization curve shows a concave H dependence below T_max \sim40 K which is
higher than the transition temperature T_0 \sim29 K. The magnetic
susceptibility along the a-axis shows a smooth and continuous decrease down to
\sim20 K below T_max \sim40 K without showing an anomaly at T_0. From these two
results, a Kondo singlet is formed below T_max and coexists with the antiferro
magnetic order below T_0. We also propose that the larger suppression of the
spin degrees of freedom along the a-axis than along the c-axis below T_max is
associated with the origin of the antiferro magnetic component.Comment: 4 pages, 4 figures, to appear in Phys. Rev. B, Rapid Commu
Long-range order and low-energy magnetic excitations in CeRu2Al10
The nature of the unconventional ordered phase occurring in CeRu2Al10 below
T0 = 27 K was investigated by neutron scattering. Powder diffraction patterns
show clear superstructure peaks corresponding to forbidden (h + k)-odd
reflections of the Cmcm space group. Inelastic neutron scattering experiments
further reveal a pronounced magnetic excitation developing in the ordered phase
at an energy of 8 meV.Comment: 5 pages; 4 figure
Neutron scattering study of the long-range ordered state in CeRu2Al10
Elastic and inelastic neutron scattering measurements have been performed on
powder and single-crystal samples of orthorhombic CeRu2Al10. The order forming
below T0 = 27 K was identified as a long-range antiferromagnetic state with the
wave vector k = (1,0,0). The magnetic spectral response in the ordered phase,
measured on powder, is characterized by a spin gap and a pronounced peak at 8
meV, whose Q dependence suggests a magnetic origin. Both features are
suppressed when temperature is raised to T0, and a conventional relaxational
behavior is observed at 40 K. This peculiar spin dynamics is discussed in
connection with recent magnetization results for the same compound.Comment: 5 pages, 5 figures, International Conference on Heavy Electrons 2010
(Tokyo Metropolitan University, September 17 - 20, 2010), to be published in
Journal of the Physical Society of Japan. Typo corrected p. 3: "sites denoted
1 and 3" => "1 and 4
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