Differential Production of Proteolytic Enzymes by Normal (KMS-6), Immortally Transformed (KMST-6), and Tumorigenetically Transformed (Ha-KMST-6) Human Fibroblasts

Production of proteolytic enzymes by human fibroblasts in the process of transformation was investigated in order to learn which step, the immortalizing or tumorigenic step, is more important for malignant transformation of human cells. The cells used were normal human fibroblasts (KMS-6), fibroblasts immortally transformed by treatment with Co-60 gamma rays (KMST-6), and KMST-6 cells further tumorigenetically transformed KMST-6 cells by infection with Harvey murine sarcoma viruses (Ha-KMST-6). Proteolytic enzymes in culture medium or cells were assayed using synthetic substrates, N-a-(p-tosyl)-L-arginine [3H]methyl ester hydrochloride and H-D-val-leu-lys-p-nitroaniline. Our results showed that the immortally transformed KMST-6 cells produced a larger amount of the enzymes than the normal and the tumorigenetically transformed cells. Since elevated production of proteolytic enzymes has been reported to correlate well with malignant transformation of cultured rodent or avian cells by many other investigators, our present results indicate that our immortalized human fibroblasts have already acquired properties characteristic to cancer cells

Quantitative evaluation of temporal partial coherence using 3D Fourier transforms of through-focus TEM images

AbstractWe evaluate the temporal partial coherence of transmission electron microscopy (TEM) using the three-dimensional (3D) Fourier transform (FT) of through-focus images. Young's fringe method often indicates the unexpected high-frequency information due to non-linear imaging terms. We have already used the 3D FT of axial (non-tilted) through-focus images to reduce the effect of non-linear terms on the linear imaging term, and demonstrated the improvement of monochromated lower-voltage TEM performance [Kimoto et al., Ultramicroscopy 121 (2012) 31–39]. Here we apply the 3D FT method with intentionally tilted incidence to normalize various factors associated with a TEM specimen and an imaging device. The temporal partial coherence of two microscopes operated at 30, 60 and 80kV is evaluated. Our method is applicable to such cases where the non-linear terms become more significant in lower acceleration voltage or aberration-corrected high spatial resolution TEM

A Rhombic Dodecahedral Honeycomb Structure with Cation Vacancy Ordering in a γ-Ga2O3 Crystal

The crystal structure of a γ-Ga2O3 layer grown epitaxially on an MgO substrate by a vapor phase transport method was investigated by transmission electron microscopy, electron diffraction, and scanning transmission electron microscopy with aberration correctors. Some forbidden reflections were excited in electron diffraction patterns by double reflection from the vicinity of the substrate interface. Phase boundaries are observed in atomic column images using high-angle annular dark field images. A structure model is proposed to explain the experimental results. Cation vacancy ordering is introduced in the structure model to distort the γ-Ga2O3 crystal lattice along one axis and reduce the lattice mismatch with the substrate. Some grains are formed and alter the directions to reduce the distortion for the other axis. The grains are stacked with {110} phase boundaries and form a rhombic dodecahedral honeycomb. The rhombic dodecahedral honeycomb structure model with cation vacancy ordering is stabilized by the lattice mismatch between the γ-Ga2O3 crystal and the MgO substrate, and it disappears at a depth of 170 nm from the interface