Electron tomography (ET) is a useful tool to investigate three-dimensional details based on virtual slices of relative thick specimen, and it requires complicated procedures consisted of image acquisition steps and image processing steps with computer program. Although the complicated step, this technique allows us to overcome some limitations of conventional transmission electron microscopy: (1) overlapping of information in the ultrathin section covering from 30 nm to 90 nm when we observe very small structures, (2) fragmentation of the information when we study larger structures over 100 nm. There are remarkable biological findings with ET, especially in the field of neuroscience, although it is not popular yet. Understanding of behavior of synaptic vesicle, active zone, pooling and fusion in the presynaptic terminal have been enhanced thanks to ET. Some sophisticated models of postsynaptic density with ET and immune labeling are introduced recently. In this review, we introduce principles, practical steps of ET and some recent researches in synapse biology.

This study examined the effects of quercetin on corneal opacity caused by corneal edema by suppressing the damage on corneal endothelial cell, which was induced by mitomycin-C (MMC). In the MMC-treated group, the number of keratocytes was noticeably fewer compared to that of other groups. Although this group showed normal amount of fiber in the corneal stroma, the thickness was shown to be very thick and the alignment of the corneal endothelial cells that worked as the barrier against aqueous humor was irregular. According to such results, it was known that corneal opacity induced by MMC is not caused by proliferation of keratocytes, but by corneal edema triggered by the infiltration of aqueous humor. In the MMC+quercetin and quercetin+MMC-treated groups, the number of keratocytes was higher and polymorphonuclear leukocytes infilteration was lower significantly compared to that of the MMC-treated group. Although the amounts of fiber and endothelioid cell arrangement were normal, there was more space observed in the corneal stroma. Nonetheless, these groups showed significantly lower stromal thickness compared to that of the MMC group. In conclusion, quercetin has the effect on the reduction of corneal opacity caused by corneal edema that work MMC-induced damage to the corneal endothelial cells.

Study on the egg envelope of an endemic Korean freshwater fish, Coreoleuciscus splendidus was carried out by light and scanning electron microscopes during its spawning season. The egg envelope on the entire egg is filled with plenty of long cylinder-like villi before and after fertilization. The fertilized eggs consist of two regions, the attaching and non-attaching parts to stick to the substrates. The villi covering the fertilized eggs have three kinds of villi in its length: 1) normal- sized villi of an average of $10.6{\mu}m$ on the non-attachment part; 2) longer and more slender villi over about $20{\mu}m$ on the attachment part, at least being two times longer than those of the non-attachment; and 3) shorter villi under about $5.0{\mu}m$ around the micropyle, with half the size of the non-attachment villi. The micropyle rotated in a counter-clockwise direction with five pieces of the ridges.

As decreasing device size, probing of nanoscale surface properties becomes more significant. In particular, nanoscale probing of surface potential has paid much attention for understanding various surface phenomena. In this article, we review different atomic force microscopy techniques, including electrostatic force microscopy and Kelvin probe force microscopy, for measuring surface potential at the nanoscale. The review could provide fundamental information on the probing method of surface potential using atomic force microscopy.

The microstructure of as-quenched $Al_{70}Cu_{18}Mg_{12}$ alloy has been investigated in detail using transmission electron microscopy. Al nano-crystals about 5 nm with a high density are distributed in the amorphous matrix, indicating amorphous matrix nano-composite can be synthesized in Al-Cu-Mg alloy. The high density of Al nano-crystals indicates very high nucleation rate and sluggish growth rate during crystallization possibly due to limited diffusion rate of solute atoms of Cu and Mg during solute partitioning. The result of hardness measurement shows that the mechanical properties can be improved by designing a nano-composite structure where nanometer scale crystals are embedded in the amorphous matrix.