Synthesis of Heterocycle-Containing [60]Fullerene Derivatives. II.1 Recent Progress in [4 2]- and [3 2]-Cycloaddition Routes

Recent progress of synthesis of C₆₀ derivatives functionalized with hetero-cycles is reviewed, focusing attention on [4+2]- and [3+2] cycloaddition methodologies and oxidative heterocyclization.     

Basic fibroblast growth factor as one of the essential factors regulating lens transdifferentiation of pigmented epithelial cells

In vitro transdifferentiation of retinal pigmented epithelial cells of the chick embryo into lens cells can be markedly enhanced by culture in the presence of testicular hyaluronidase and phenylthiourea. Since the commercial preparations of hyaluronidase that had previously been used were very crude, a search for the actual effective molecule(s) enhancing lens transdifferentiation was conducted. First, we purified the enzyme and tested the effect of the purified hyaluronidase. Highly purified hyaluronidase itself did not enhance lens transdifferentiation. The crude hyaluronidase was then separated according to affinity with heparin, considering the possibility that the fibroblast growth factor (FGF) is contained in the crude hyaluronidase. Transdifferentiation-enhancing activity was detected in the fraction which was bound to heparin and eluted with 2 M NaCl, where no hyaluronate-degrading activity existed. Analysis of the fraction by SDS-PAGE revealed the existence of an 18 kDa protein whose NH2-terminal sequence was identical to that of basic FGF. The basic FGF derived from bovine brain also enhanced lens transdifferentiation of pigmented epithelial cells. These findings suggest that basic FGF must play a major role in enhancing transdifferentiation of pigmented epithelial cells to lens cells.     

Cytokines and immune regulation in thyroid autoimmunity

We studied the role of cytokines and immune regulation in thyroid tissue from patients with Graves' disease. Immunohistochemistry showed that the thyroid glands are characterized by an aberrant expression of HLA class II antigens on thyrocytes, generation of new blood vessels and infiltration of mononuclear cells. We demonstrated that CD4+ memory cells were more frequent in thyroid glands from Graves' patients than were CD4+ naive cells. The intrathyroidal T cells demonstrated an enhanced expression of the adhesion molecules LFA-1, CD2, VLA-4 and VLA-5, and vascular endothelial cells of capillaries and thyrocytes in thyroid glands reacted with anti-ICAM-1 monoclonal antibody. The adhesion molecules and HLA antigens on both vascular endothelial cells and thyrocytes were regulated by inflammatory cytokines. These results suggest that circulating lymphocytes migrate into thyroid tissues and that memory T cells are retained in the thyroid tissues by cellular interactions with thyrocytes or with extracellular matrix.     

An effect of microstructure on the interface resistance between a perovskite-type oxide electrode and yttria-stabilized zirconia

The electrode characteristics of perovskite-type oxides, La_0.6Sr_0.4CoO₃ and La_0.6Sr_0.4MnO₃, on ceria-based oxide and stabilized zirconia were analysed by the a.c. impedance method. The ionic conductivities of the electrolyte and electrode conductivities from the a.c. impedance analysis agreed with those obtained from the current interruption and d.c. four-probe methods. Two semicircles from the charge transfer and diffusion processes appeared as the electrode resistance. The relative contribution of these two processes to the overall electrode resistance strongly depended on the microstructure of the electrode. The electrode microstructure could be controlled by the dispersion medium used for the electrode slurry. The La_0.6Sr_0.4MnO₃ electrode coated with n-butyl acetate slurry exhibited the smallest electrode resistance.     

Relationship between Transformation Temperature and Time-Temperature-Transformation Curves of Tetragonal-to-Monoclinic Martensitic Transformation in Zirconia-Yttria System

The tetragonal → monoclinic ( t → m ) martensitic phase transformation in ZrO₂–0.5–4 mol% Y₂O₃ proceeds during isothermal aging at various temperatures from 350 to 800 K; i.e., the transformation increases sigmoidally with aging time. The time-temperature-transformation ( T - T - T ) curves show a typical C shape, with very high rate for lower Y₂O₃-content specimens, and the rate decreases with higher Y₂O₃ content. The transformation temperature ( M _s) of the t → m transformation obtained from dilatation curves during the cooling stage coincides well with C curves above the nose temperature. The t → m transformation should occur isothermally, as suggested by a nucleation and growth mode.     

Development of a high‐resolution RGBW flexible display using a white organic light‐emitting diode with microcavity structure and that of a side‐roll touch panel

In this study, white organic electroluminescent devices with microcavity structures were developed. A flexible high‐resolution active‐matrix organic light‐emitting diode display with low power consumption using red, green, blue, and white sub‐pixels formed by a color‐filter method was fabricated. In addition, a side‐roll touch display was developed in combination with a capacitive flexible touch screen.     

Promotion of hydrogen permeation on metal-dispersed alumina membranes and its application to a membrane reactor for methane steam reforming

A mesoporous membrane for selective separation of hydrogen was prepared usingthe sol-gel method. Some metal salts such as RuCl₃, Pd(NH₃)₄Cl₂, RhCl₃,, and H ₂PtCl₆, were added to the boehmite sol and coated on a porous alumina substrate before firing at 500°C. It was foundthat the permeability of hydrogen and the separation factor for a hydrogen-nitrogen gaseous mixture of these metaldispersed membranes exceeded the limitations of the Knudsen diffusion mechanism. Although the gas permeation through a neat alumina membrane is governed by the Knudsen diffusion, the metals dispersed in alumina membranes were effective in promoting hydrogen permeation. These metaldispersed alumina membranes were also used in a membrane reactor for methane steam reforming at low temperature. In the temperature range of 300 to 500°C, the membrane reactor attained a methane conversion twice as high as the equilibrium value of the packed bed catalytic reactor system as a result of the selective removal of hydrogen from the reaction system.