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        Nucleation of Diamond over Nanotube Coated Si Substrate Using Hot Filament Chemical Vapor Deposition (CVD) System

        신형식,김길성,Shafeeque G. Ansari,Hyung-Kee Seo,Mushtaq Ahmad Dar,Md. Shahjahan 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.1

        We studied the use of carbon nanotubes as a seeding layer for the nucleation of diamond on Si (10) sub-strate by using a hot filament chemical vapor deposition (HFCVD) system. Prior to deposition, substrates were seededwith multi-wal carbon nanotube (MWCNT) powder which was prepared separately. MWCNTs were used as nucle-ation precursors. The diamond grains grew esentialy over the nanotubes with a higher growth density in comparisonwith the un-seeded substrates. The scaning electron microscopy (SEM) image of surface morphology shows crystal-lites of cauliflower shaped grains. The micro Raman spectroscopic results show a sharp peak at 1,332 cm-1 corespond-ing to diamond phase. X-ray photoelectron spectroscopic study show the presence of carbon (C1s) phase.

      • KCI등재

        Comparative Study of Diamond Films Grown on Silicon Substrate Using Microwave Plasma Chemical Vapor Deposition and Hot-Filament Chemical Vapor De- position Technique

        신형식,김영순,강길선,Mushtaq Ahmad Dar,Shafeeque G. Ansari,Hyung-il Kim,Chu Van Chiem 한국화학공학회 2005 Korean Journal of Chemical Engineering Vol.22 No.5

        Diamond films on the p-type Si(111) and p- type(100) substrates were prepared by microwave plasma chemical vapor deposition (MWCVD) and hot-filament chemical vapor deposition (HFCVD) by using a mixture of methane CH4 and hydrogen H2 as gas feed. The structure and composition of the films have been investigated by Xray Diffraction, Raman Spectroscopy and Scanning Electron Microscopy methods. A high quality diamond crystalline structure of the obtained films by using HFCVD method was confirmed by clear XRD-pattern. SEM images show that the prepared films are polycrystalline diamond films consisting of diamond single crystallites (111)-orientation perpendicular to the substrate. Diamond films grown on silicon substrates by using HFCVD show good quality diamond and fewer non-diamond components.

      • 급속진행형 치주염에서 국소약물 송달제제의 효과에 관한 연구

        신형식,박귀운 원광대학교 치의학연구소 1994 圓光齒醫學 Vol.4 No.1

        The purpose of this study was to assess the effect of polycaprolactone strip with minocycline on the periodontal pocket in humans and the various clinical parameters in rapidly progressive periodontitis. Nine patients with rapidly progressive periodontitis were selected for the study. They had not taken antibiotics for 6 months and had no history of dental treament for 6 months before the study. They were in good general health. By the split-mouth method, patients received a supragingival scaling, experimental group (9 sites)were subjected to subgingival placement of polycaprolactone strips(1 strip) containg 30% minocycline and control group (9 site) were subjected to subgingival placement of not polycaprolactone strips (1 strip) containg 30% Minocycline. Strips were replaced with freshly filled ones at 1 week and 2 week. All strips were removed from pockets at 3 week. Clinical examination (plaque index, gingival index, probing pocket depth,) and distribution of the bacteria morphology of subgingival plaque were monitored on baseline (0 week), 1 week, 2 week, 4 week and 8 week. The result were as follows: 1. Plaque index in experimental group was not significantly reduced during all weeks(P<0.05), but slightly reduced at 2, 4 and 8 weeks and that in control group was not significantly reduced during monitoring period. 2. Probing pocket depth was significantly reduced at 2, 4 and 8 weeks(P<0.05) in experimental group, but that in control group was not siginificantly changed during monitoring period. 3. Gingival index was significantly improved at 2, 4 and 8 weeks(P<0.05) in experimental group but that in control group was not significantly changed. 4. Percentage of cocci was significantly increased at 2, 4 and 8 weeks in experimental group but that in control group was not significantly changed. 5. Percentage of non-motile rods in both group were not significantly changed when compared with those of baseline (0 week) (P<0.05). 6. Percentage of motile rods was siginificantly reduced at 1, 2 and 4 weeks in experimental group (P<0.05) but that in control group was not significantly changed. 7. Percentage of spirochetes was siginigicantly reduced during all weeks(P<0.05) but that in control group was not significantly changed. The result showed that polycaprolactone containing 30% minocycline effect the clinical index and bacterial morphotype.

      • KCI등재후보
      • KCI등재
      • 치주조직 유관세포에서의 Nitric Oxide 및 Nitric Oxide Synthetase의 생물학적 특성에 관한 연구

        신형식,윤형진 원광대학교 치의학연구소 1998 圓光齒醫學 Vol.8 No.1

        Bone remodeling is characterized by the coupling of osteoclast-mediated bone resorption and osteoblast-mediated bone formation. The process is tightly regualted at the local level by an incompletely known netwotk of peptide and non-peptide fators. Nitric oxide(NO), synthesized by nitric oxide synthetase(NOS) from L-arginine, is becoming recognized as an important bio-regualtory molecule in a variety of tissue, but little is known about its possible role in periodontal tissue. The purpose of this study is to investigate the expression of nitric oxide synthetase(NOS) in inflamed gingiva and the effects of cytokine on the expression of NOS protein. The expression of NOS in gingival tissue was evaluated by immunohistochemical staining for NOS,, NOS2, NOS3. The effect of cytokine on the expression of NOS in human periodontal ligament cells and osteoblast-like HOS cells by western blot analysis. Further, we studied that NO functions in periodontal ligment cells as a regulatory molecule. PDL cells incubated with NOS inhibitor and donor. The protein expression, type I collagen & non-collagenous protein, nitrate production and cell proliferation were evaluated. The results were as follows. 1. NOS_1, NOS_2, NOS_3 was rarely distributed in healthy gingiva, but stronger stained in gingival epithelium, endothelial cells, and mononuclear cells of inflammed gingiva. 2. The cytokine stimulated NOS_1, and NOS_3 protein were not inducing or inhibitory effect to compared with control in PDL and HOS cells. 3. Incubation of cells with combination of TNF-α, IFN-γ, LPS result in a time dependant increase in NOS_2 expression, reaching a maximal level after 24 hours of stimulation. 4. The osteonectin protein inhibitory effect of NMA, inhibitor of NOS, was reversed by L-arginine in dose dependant manner. 5. NMA decreased cell proliferation and nitrate production, but the inhibitory efffect of NMA was also prevented by the NO donor, sodium nitropruiside. These results suggest that exogenously synthesized NO was playing a stimulating effect on cell proliferation or on non-collagenous protein expression. Therefore NO have an important role in mediation of localized bone destruction associated inflammatory bone disease such as periodontitis.

      • 황련이 Lipopolysaccharide를 처리한 치주인대세포의 세포활성 및 IL-6 생산에 미치는 영향

        신형식,유형근,송기범 원광대학교 치의학연구소 1997 圓光齒醫學 Vol.7 No.1

        In infectious disease, invasion of host tissue by bacteria or their products frequently induces a wide variety of inflammatory and immunopathologic reaction. Evidence indicates that cytokines are involved in the initiation and progression of chronic inflammatory diseases, such as periodontitis. Interleukin-6, which is a multifunctional cytokine, has important roles in acute and chronic inflammation and may also be implicated in bone resorption. Periodontal diseases are characterized by chronic inflammation of the periodontium with alveolar bone resoption. A principal driving force behind this response appears to lie in the immune system's response to bacteria. Many of the cell components which have been shown to function as virulence factors in gram-negative bacteria are associated with the bacterial surface. Of these, lipopolysaccharide has been chars cterized as one that mediates a number of biological activities which can lead to the destruction of host tissue. Non-steroidal antiinflammatory drug is used for reduce inflammation, and most of NSAIDs inhibit prostaglandin E, production, but it is shown that PGE_2 production is stimulated by IL-β in recent study. So, the influence of other cytokines except PGE_2 on periodontium can not be avoided. Therefore, new antiinflammatory drug is needed. Rhizoma coptidis is used in oriental medicine for anti-inflammation and antiseptics. In this present study, we examined the IL-6 release in periodontal ligament cells treated with the lipopolysaccharide, and also the effect of rhizoma coptidis on cellular activity and IL-6 production of periodontal ligament cells. To evaluate the effect of rhizoma coptidis on cellular activity, the cells were seeded at a cell density of 1×10^4 cells/well in 24-well culture plates. After one day incub ation, 10^-6, 10^-9 and 10^-12g/㎖ of rhizoma coptidis and 5, 10㎍/㎖ of LPS were added to the each well and incubated for 1 and 2 days, respectively. Then, MU assay were carried out. To evaluate the effect of rhizoma coptidis on IL-6 production, the cells were seeded at a cell density of 1.5×10^4 cells/well in 24-well culture plates. After one day incubation, 10^-9g/㎖ of rhizoma coptidis and 5, 10㎍/㎖ of LPS were added to the each well and incubated for 3, 6, 12 and 24 hours. Then, amounts of IL-6 production is measured by IL-6 ELISA kit used. The -results were as follows. 1. Rhizoma coptidis(below to 10^-6g/㎖) significantly increaed cellular activity of periodontal ligament cells than control. 2. Rhizoma coptidis(10^-9g/㎖) significantly increased cellular activity of LPS(5㎍/㎖)-treated periodontal ligament cells than control. 3. LPS(5 and 10㎍/㎖) significantly increased IL-6 production of periodontal ligament cells than control. 4. Rhizoma coptidis(10^-9g/㎖) decreased IL-6 production of LPS(5㎍/㎖)-treated periodontal ligament cells than LPS only tested group. These findings suggest that stimulation of the IL-6 release of periodontal ligament cells by LPS may have a role in the progression of inflammation and alveolar bone resorption in periodontal disease, and that inhibition of the IL-6 release of cells and stimulation of cellular activity by rhizoma coptidis may help the periodontal regeneration.

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