48.    Comparison of microscopic images of human and mammalian hair shafts using hard X-ray microscopy. 
Seung Phil Hong, Soo Young Jeon, Tak Heon Oh, Jawoong Goo, Seok Yong Ahn, Hwa Shik Yoon(1), Won-Soo Lee,   Department of Dermatology and Institute of Hair and Cosmetic Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea, 1. Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, Korea.

There have been used various methods of hair investigation. Among them, scanning and transmission electron microscopies have been widely used in the field of ultrastructural study of hair. But, because these methods need sample processing procedures and inevitably devitalize samples, these are limitedly valuable. Rcently, it was introduced that microscope using highly coherent, bright third generation x-ray could be an alternative way to visualized the ultrastucture of material. The hard x-ray from the third generation synchrotron light source has a higher energy with better penetration and there is no needs to sample preparation so it is more suitable for the biological samples without processing artifacts or damage to samples. We investigated the ultrastructure of human and some mammalian hair shafts, including dog, cat, mouse, cow, rabbit and rat. Three distinct structures (medulla, cortex, and cuticular layer) of hair shaft were clearly distinguished in all species except cat. We also could find that the detailed characters of each sample were different. Among them, the most distinct characteristics is the cortex structures.