RESUMEN
X-ray absorption spectra at the Ti K-edge of a SrTiO3 single crystal under uniaxial pressure were measured to obtain evidence of uniaxial pressure-induced polarization predicted in SrTiO3 from the electronic viewpoint. The pre-edge 3d-e g peak decreases in intensity with increasing uniaxial pressure, together with an energy shift to higher energy side. Contrary to uniaxial deformation, these changes were independent of incident x-ray polarization. This implies the presence of a mechanism that maintains the isotropic coordination environment around a Ti atom, i.e. a tilt and rotation of the TiO6 octahedron accompanied by its isotropic shrinkage, hence the local polarization essential to the ferroelectric order cannot be observed.
RESUMEN
The GPR119 was recently shown to be activated by oleoylethanolamide (OEA), a naturally occurring bioactive lipid with hypophagic and anti-obesity effects. In this study, we have cloned and characterized its murine counterpart, Gpr119. The full-length cDNA contained an open reading frame of 1008bp encoding a 335-amino acid protein. The genomic organization of Gpr119 was unique, having a 3'-untranslated second exon that was also involved in an alternative splicing event. Gene expression analyses confirmed its specific expressions in pancreatic islets and two endocrine cell-lines, MIN6 and alphaTC1. Immunohistochemistry and double-immunofluorescence studies using a specific antibody revealed the predominant Gpr119 localization in pancreatic polypeptide (PP)-cells of islets. No definitive evidence of Gpr119-immunoreactivity in adult beta- or alpha-cells was obtained. The Gpr119 mRNA levels were elevated in islets of obese hyperglycemic db/db mice as compared to control islets, suggesting a possible involvement of this receptor in the development of obesity and diabetes.