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송현섭,김상철 원광대학교 치의학연구소 1990 圓光齒醫學 Vol.1 No.1
The purpose of this study was to inverstigate and compare the biomechanical properties of orthodontic rubber elastic materials. Latex bands, nylon-covered elastic threads and polyurethane-based elastic modules, delivering 205±10grams force to 30㎜ stretching state were selected and stored separately in 3 environments-air (22±3℃), distilled water (37±1℃), or natural saliva (37±1℃), And, the amount of remaining force and permanent elongation of each sample were measured on Instron at interval of 1 hour, 6 hours, 12 hours, 24 hours, 1 week, and 2 weeks. So the data derived were analyzed statistically. The results were as follows 1 . Force decay and permanent elongation of all materials increased with time lapsed ; elastic module, latex band and nylon-covered elastic thread in that order of the amount of force decay ; elastic module, elastic thread, latex band in that order of the amount of permanent elongation. 2. Among environmental conditions, force decay and permanent elongation in natural saliva, most increased, and those in air, least increased. 3. There was a negative correlation between force decay and permanent elongation. 4. Force decay and permanent elongation were most affected by the material itself, time and environments in that order. 5. After 24 hours in saliva, the percentage of remaining force in elastic module was 51.9%(107.37grams) : in latex band, 83.2%(172.62grams) : in elastic thread, 85.0%(17925grams). After 2 weeks in saliva, the percentage of remaining force in elastic module was 42.9 %(88.75grams) in latex band, 74.5% (154.50grams) : in elastic thread, 77.6% (163.75grams).
Highly permeable porous polymer nanofiber membrane for efficient particulate matter removal
송현섭,조은선 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1
Particulate matter (PM) have induced growing adverse effects on public health, also threatening ecosystems. Various efforts have been made to reduce the generation of fine dust or to remove it from the air. In particular, polymer nanofiber membranes have been widely studied to mitigate the aftermath of PM pollution, attributed to their versatile tunability and excellent filtration property. In this study, highly porous polymer membranes were fabricated for an efficient PM removal with a controlled pore size over the nanofibers. The effect of porosity on the filtration performance was investigated, along with the impact of dipole moment of polymers. It will enable us to design and manipulate the optimized porous membrane structure with an excellent quality factor to effectively eliminate PM.
Vitamin D_3와 TGF-β가 치주인대세포 활성에 미치는 영향에 관한 연구
송현섭,김상철 원광대학교 치의학연구소 1995 圓光齒醫學 Vol.5 No.2
TGF-β is a polypeptide with multiple physiological functions in regulation of cell-to-cell interaction and in growth and development. The active form of vitmain D_3, 1,25-dihydroxycholecalciferol [1.25-(OH)_2D_3], is one of the most potent stimulators of osteoclastic acitivity. The purpose of this study was to evaluate the effect of Vitamin D_3 and/or TGF-β on the periodontal ligament(PDL) cells. Human PDL cells were prepared from the first premolars extracted for the orthodontic treatment and were incubated in the environment of 37℃, 5% CO_2 and 95% humidity. 10, 50 or l00ng/㎖ of 1,25-(OH)_2D_3. and 0.1, 1, 5 or l0ng/㎖ of TGF-β were administered to the culture wells, separately or in combination. And the viability of PDL cells was evaluated by MTT assay. The obtained results were as follows. 1. The viability of PDL cells in l0ng/㎖ vitamin D_3 was not significantly differenent from that of the control group at 1, 2 and 3-day of cultivation, but it was significantly increased in 50ng/㎖ of Vitamin D_3 at 3-day and in l00ng/㎖ of Vitamin D_3 at 2 and 3-day. 2. The viability of PDL cells in 0.lng/㎖ of TGF-β was not significantly differenent from that of the control group at 1, 2 and 3-day of cultivation, but it was significantly increased in 1 and 5ng/㎖ of TGF-β at 3-day of cultivation, and in 10ng/㎖ of TGF-β at 2 and 3-day of cultivation. 3. In case of admixture of lng/㎖ TGF-β and the various concentrations of vitamin D_3, the viability of PDL cells was significantly increased in the admixture of l00ng/㎖ of vitamin D_3 at 3-day of cultivation 4. In case of admixture of 5ng/㎖ of TGF-β and the various concentrations of vitamin D_3, the viability of PDL cells began to be increased from 2-day of cultivation in the admixture of 10 50 and l00ng/㎖ of vitamin D_3, but it was not maintained at 3-day in the admixture of l0ng/㎖ of vitamin D_3. 5. In case of admixture of l0ng/㎖ of TGF-β and the various concentrations of vitamin D_3, the viability of PDL cells was significantly increased in the admixture of 50ng/㎖ of vitamin D_3 at 2 and 3-day of cultivation, and in the admixture of l00ng/㎖ at 1, 2 and 3-day.