Preparation and Observation of Fresh-frozen Sections of the Green Fluorescent Protein Transgenic Mouse Head

Hard tissue decalcification can cause variation in the constituent protein characteristics. This paper describes a method of preparating of frozen mouse head sections so as to clearly observe the nature of the constituent proteins. Frozen sections of various green fluorescent protein (GFP) transgenic mouse heads were prepared using the film method developed by Kawamoto and Shimizu. This method made specimen dissection without decalcification possible, wherein GFP was clearly observed in an undamaged state. Conversely, using the same method with decalcification made GFP observation in the transgenic mouse head difficult. This new method is suitable for observing GFP marked cells, enabling us to follow the transplanted GFP marked cells within frozen head sections

Junior High School Students\u27 Mental Health, Menstruation and Body Image

藤井稔教授退職記念,　II.研究論

Morphological transformation of sensory ganglion neurons and satellite cells

The development of sensory ganglion neurons and satellite cells examined by scanning electron microscopy after removal of the connective tissue is reviewed. Sensory neurons are bipolar at early stages of development and later became pseudounipolar. This maturation event starts earlier but proceeds more slowly in chick than in rat embryos. These may due to the difference in the extent and intimacy of satellite cell investments between these two animal species. The neuronal perikaryal projections are observed by scanning electron microscopy after removal of the connective tissue and satellite cells. The morphometric analysis reveals that perikaryal projections are more numerous on the surface of mature pseudounipolar neurons than on that of premature bipolar neurons; they increase in number as the neuronal cell bodies grow larger. This may support the hypothesis that perikaryal projections are structural devices for increasing the neuron-satellite interface and for improving the efficiency of metabolic exchange between these two cell types.The important role of satellite cells in neuronal maturation is discussed.Biomedical Reviews 2000; 11: 39-52

Analysis of the Surface Oxidation Process on Pt Nanoparticles on a Glassy Carbon Electrode by Angle-Resolved, Grazing-Incidence X‑ray Photoelectron Spectroscopy

We have analyzed the surface oxidation process of Pt nanoparticles that were uniformly dispersed on a glassy carbon electrode (Pt/GC), which was adopted as a model of a practical Pt/C catalyst for fuel cells, in N₂-purged 0.1 M HF solution by using angle-resolved, grazing-incidence X-ray photoelectron spectroscopy combined with an electrochemical cell (EC-ARGIXPS). Positive shifts in the binding energies of Pt 4f spectra were clearly observed for the surface oxidation of Pt nanoparticles at potentials <i>E</i> > 0.7 V vs RHE, followed by a bulk oxidation of Pt to form Pt­(II) at <i>E</i> > 1.1 V. Three types of oxygen species (H₂O_ad, OH_ad, and O_ad) were identified in the O 1s spectra. It was found for the first time that the surface oxidation process of the Pt/GC electrode at <i>E</i> < ca. 0.8 V (OH_ad formation) is similar to that of a Pt(111) single-crystal electrode, whereas that in the high potential region (O_ad formation) resembles that of a Pt(110) surface or polycrystalline Pt film

Oxygen Reduction Reaction Activity and Durability of Pt Catalysts Supported on Titanium Carbide

We have prepared Pt nanoparticles supported on titanium carbide (TiC) (Pt/TiC) as an alternative cathode catalyst with high durability at high potentials for polymer electrolyte fuel cells. The Pt/TiC catalysts with and without heat treatment were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Hemispherical Pt nanocrystals were found to be dispersed uniformly on the TiC support after heat treatment at 600 °C in 1% H2/N2 (Pt/TiC-600 °C). The electrochemical properties (cyclic voltammetry, electrochemically active area (ECA), and oxygen reduction reaction (ORR) activity) of Pt/TiC-600 °C and a commercial Pt/carbon black (c-Pt/CB) were evaluated by the rotating disk electrode (RDE) technique in 0.1 M HClO4 solution at 25 °C. It was found that the kinetically controlled mass activity for the ORR on Pt/TiC-600 °C at 0.85 V (507 A g−1) was comparable to that of c-Pt/CB (527 A g−1). Moreover, the durability of Pt/TiC-600 °C examined by a standard potential step protocol (E = 0.9 V↔1.3 V vs. RHE, holding 30 s at each E) was much higher than that for c-Pt/CB