Fabrication and Characterization of a One-dimensional Fiber-optic Dosimeter for Electron Beam Therapy Dosimetry / 의학물리

In this study, we have fabricated a one-dimensional fiber-optic dosimeter for electron beam therapy dosimetry. Each fiber-optic dosimeter has an organic scintillator with a plastic optical fiber and it is embedded and arrayed in the plastic phantom to measure one-dimensional high energy electron beam profile of clinical linear accelerator. The scintillating lights generated from each sensor probe are guided by plastic optical fibers to the multi-channel photodiode amplifier system. We have measured one-dimensional electron beam profiles in a PMMA phantom according to different field sizes and energies of electron beam. Also, the isodose and three-dimensional percent depth dose curves in a PMMA phantom are obtained using a one-dimensional fiber-optic dosimeter with different electron beam energies.

Finite element analysis on screw type implant in the type IV regenerated bone

Expression of Periostin and S100A2- S100A4-Calcium Binding Proteins mRNA in Human Gingival Fibroblasts and Periodontal Ligament Fibroblasts / 대한치주과학회지

Gingival fibroblasts(GF) and periodontal ligament fibroblasts(PDLF) are the major cellular components of periodontal soft connective tissues, but the precise molecular biological differences between these cells are not yet known. In the present study, we investigated the expression of S100A4, S100A2 calcium-binding protein and osteoblast-specific factor 2(OSF-2, Periostin) mRNA in GF and PDLF in vitro through the process of reverse transcription-polymerase chain reaction(RT-PCR) and Northern blot analysis in each. Human GF and PDLF were isolated from the gingival connective tissue and the middle third of freshly extracted healthy third molars. They were cultured in Dulbecco's Modified Eagle Medium(DMEM) containing 10% fetal bovine serum and cells in the third passage were used in the experiments. After extracting total RNA from cultured cells, RT-PCR and Northern analysis were performed using S100A4-, S100A2- and Periostin-specific oligonucleotide primers and subcloned cDNA probes in each. In RT-PCR and Northern analysis, the expression of S100A4 and Periostin mRNA in GF was slightly detectable. Interestingly, the expression of S100A4 and Periostin mRNA in PDLF was much higher than that in GF. On the other hand, S100A2 mRNA was highly expressed in both GF and PDLF. Since there was a marked difference of S100A4 and Periostin expression between GF and PDLF in vitro, these data suggest that S100A4 and Periostin could be used as a useful marker for distinguishing cultured gingival fibroblasts and periodontal ligament cells.