• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.785-804
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• 1997

It was well known that calcium sulfate was biocompatible, resorbed rapidly in the body, had potential as a good barrier membrane. Platelet-derived growth factor(PDGF) was one of polypeptide growth factor that had been reported as a biological mediator which regulates activities of wound healing process including the cell proliferation, migration and metabolism. The purpose of this study was to evaluate the effects of a combination of calcium sulfate and PDGF on periodontal ligament cells in vitro to use as a regeneration promoting agent of periodontal tissue. Human periodontal ligament cells were prepared from the premolar tooth extracted for the orthodontic treatment. Cells were cultured in ${\alpha}-MEM$ contained with 20% FBS, at the $37^{\circ}C$, 100% of humidity, 5% $Co_2$ incubator. Cells were inoculated and cultured into 96 well culture plate with $1{\times}10^4cells/well$ of ${\alpha}-MEM$ for 1 day. After discarding the medium, those cells were cultured in ${\alpha}-MEM$ contained with 10% FBS alone(control group), in calcium sulfate(calcium sulfate group), in calcium sulfate treated with 15ng/ml of PDGF-BB(calcium sulfate+PDGF group), in ${\alpha}-MEM$ contained with 10% FBS treated with 15ng/ml of PDGF-BB(PDGF group) for 1, 2, 3 day respectively. And then each group was characterized by examining of the cell counting, MTT assay, collagen synthesis. The results were as follows. 1. In the analysis of cell proliferation by cell counting, both calcium sulfate group and calcium sulfate plus PDGF group showed no stastically significant difference compared to control group, but there was stastically significant difference between PDGF group and calcium sulfate group at 1, 2 day(P<0.05). 2. In the analysis of cell proliferation by MTT assay in calcium sulfate extracts, both calcium sulfate group and calcium sulfate plus PDGF group showed no stastically significant difference compared to control group, but there was stastically significant difference between PDGF group and calcium sulfate group at 2, 3 day, and between calcium sulfate plus PDGF group and calcium sulfate group at 2 day(P

• Korean Journal of Animal Reproduction
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• v.25 no.2
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• pp.125-130
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• 2001

This study was performed to report a direct dose dependent stimulatory effect of the Flavonoid(F) on basal testosterone secretion and a dose dependent effect on LH induced testosterone production by Leydig cell of matured rats in vitro culture. F was obtained kom the Rhus vernicifua through aceton extraction and silica gel adsorption column chromatography. Leydig cells (1$\times$10$^{6}$ cells/well) from 12 weeks old rats were incubated with or without F(0, 20, 40, 80, 160 ng) or insulin-like growth factor-I(IGF-I) in the presence or absence of LH(10, 100ng). 1. The maximal stimulatory concentrations of testosterone in culture media were showed at 24hr of culture. but these testosterone level were decreased at 36 hr of culture. 2. Flavonoid(80ng) were significantly(P ＜ 0.05) increased testosterone production compared with control groups for 12 hr culture. 3. Testosterone secretion by Leydig cells stimulated with LH(10, 100ng) for 6 hr and 12hr culture compared with 3 hr culture. 4. LH 10 ng augmented testosterone were increased by addition of F 40 ng for 12 hr culture. 5. F(0 and 40 ng) also enhanced LH 10 ng stimulated testosterone for 3 hr Leydig cells culture. 6. Addition of IGF-I 100 ng to the culture medium for 6 hr were increased the concentration of testosterone by Leydig cells stimulated with 100 ng LH. These results indicate that Flavonoid has a direct stimulatory effect on basal testosterone secretion in rat Leydig cells, and also modulates LH mediated testosterone. Therefore, Flavonoid may act as a modulator on gonadal development or gonadal steroidogenesis in direct or indirect.

• Journal of Korea Water Resources Association
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• v.51 no.5
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• pp.439-449
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• 2018

Many potential sources of bias are used in several steps of the radar-rainfall estimation process because the hydrological and meteorological radars measure the rainfall amount indirectly. Previous studies on radar-rainfall uncertainties were performed to reduce the uncertainty of each step by using bias correction methods in the quantitative radar-rainfall estimation process. However, these studies do not provide comprehensive uncertainty for the entire process and the relative ratios of uncertainty between each step. Consequently, in this study, a suitable approach is proposed that can quantify the uncertainties at each step of the quantitative radar-rainfall estimation process and show the uncertainty propagation through the entire process. First, it is proposed that, in the suitable approach, the new concept can present the initial and final uncertainties, variation of the uncertainty as well as the relative ratio of uncertainty at each step. Second, the Maximum Entropy Method (MEM) and Uncertainty Delta Method (UDM) were applied to quantify the uncertainty and analyze the uncertainty propagation for the entire process. Third, for the uncertainty quantification of radar-rainfall estimation at each step, two quality control algorithms, two radar-rainfall estimation relations, and two bias correction methods as post-processing through the radar-rainfall estimation process in 18 rainfall cases in 2012. For the proposed approach, in the MEM results, the final uncertainty (from post-processing bias correction method step: ME = 3.81) was smaller than the initial uncertainty (from quality control step: ME = 4.28) and, in the UDM results, the initial uncertainty (UDM = 5.33) was greater than the final uncertainty (UDM = 4.75). However uncertainty of the radar-rainfall estimation step was greater because of the use of an unsuitable relation. Furthermore, it was also determined in this study that selecting the appropriate method for each stage would gradually reduce the uncertainty at each step. Therefore, the results indicate that this new approach can significantly quantify uncertainty in the radar-rainfall estimation process and contribute to more accurate estimates of radar rainfall.

• Bulletin of the Korean Mathematical Society
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• v.30 no.2
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• pp.179-185
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• 1993

In this article S is a topologically complete subspace of $R^{1}$i.e., the relativized topology on S may be metrized so as to make S complete. B(S) is the Borel .sigma.-field of S. For .GAMMA. one takes a set of measurable monotone (increasing or dereasing) functions on S into itself. Make the assumption of pp. There exists $x_{0}$ and a positive integer $n_{0}$ such that (Fig.) It is then shown that there exists a unique inveriant probability to which $p^{(n)}$ (x,dy) converges exponentially fast in a metric (stronger than the Kolmogorov distance); this convergence is uniform for all x .mem. S. This generalizes an earlier result of Bhattacharya and Lee (1988) who considered monotone nondecreasing maps on S.

• Membrane Journal
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• v.10 no.4
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• pp.220-229
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• 2000

Deionized water and wastewater flux were discussed using module set 1-7 composed of ultrafiltration hollow fiber type modules and reverse osmosis spiral wound type modules. The separation characteristics of ultrafiltration and reverse osmosis membranes were discussed with the variation of applied pressure and temperature. Turbidity and SS were removed effectively from ultrafiltration mem¬brane, and removal efficiency of COD, T-N, and TDS using reverse osmosis membrane was very efficient. Permeate flux increased linearly with the increase of applied pressures and temperature. It was shown that ultrafiltration and reverse osmosis membranes were suitable Lo the advanced treatment and reuse of oil refinery process effluent.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.258-259
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• 2002

광회선 분배 시스템(OXC)은 전광통신망(Optical Transport Network)에서 광신호 간 연결을 원격으로 설정해 줄 수 있는 노드(Optical Network Element)이다. OXC는 다수의 입력/출력 링크를 가지며 하나의 입력/출력 링크에는 다수의 파장 다중된 광신호 채널이 존재한다. OXC는 하나의 입력 링크를 통하여 입력되는 다수의 파장 채널을 서로 다른 출력 링크로 연결해 주거나, 다수의 입력 링크로부터 입력되는 파장채널을 하나의 출력 링크로 연곁해 줄 수 있는 optical grooming 기능을 수행한다. 또한 자국에서 광신호를 Add/Drop할 수 있는 기능을 가질 수 있다. (중략)

• Journal of Periodontal and Implant Science
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• v.26 no.3
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• pp.681-688
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• 1996

Periodontal regeneration requires the migration and proliferation of gingival fibroblasts and periodontal ligament cells. These cellular events are influenced and regulated by growth factors and some drugs. The purpose of this study is to examine the effect of Rhizoma coptidis and Centella asiatica extracts on human gingival fibroblasts. Gingival fibroblasts were primarily cultured from extracted premolar with non-periodontal diseases. Cells were cultured with ${\alpha}-MEM$ at $37^{\circ}C$, 5% $CO_2$, 100% humidity incubator for 2 or 3 days, as a measure of cell proliferation potential, it was examined that the DNA synthesis using $[^3H]-thyrnidine$ incorporation, the cell numbers (with or without dye), and cell viabilities. Rhizoma coptidis is increased the proliferation of gingival fibroblasts at concentration of $10^{-9}g/ml$, but Centella asiatica is decreased the proliferation at all concentrations. This study demonstrated that Rhizoma coptidis is a potential mitogen for human gingival fibroblasts in vitro, and we can expect the usefulness of this drug in periodontal regeneration.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.4
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• pp.40-45
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• 2010

Evaluation of uncertainty is an ongoing process that can consume time and resources. It can also require the service of someone who is familiar with data analysis techniques. Therefore, it is important for laboratory personnel who are approaching uncertainty analysis for the first time to be aware of the resources required. International inclination of measurement filed to guarantee the traceability and confidence of measurement results discards the error concept and instead analyzes the measurement uncertainty. In this paper, we analyzed the elements of measurement uncertainty on surface roughness test which are the important things in mechanical parts test. Repeat the test by 3 men, the measurement uncertainty could be calculated.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1073-1078
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• 2012

In this paper, we propose the MEMS system with Duffing equation to confirm nonlinear features in MEMS system. We also analyze nonlinear phenomena when adding the nonlinear term of another type. As a verification, we confirm chaotic motion by parameter variation through the time series, phase portrait and power spectrum.

• Proceedings of the KAIS Fall Conference
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• 2002.11a
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• pp.163-166
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• 2002

21세기에 가장 시급하게 확보되어야 하는 기술은 BT (Biotechnology)와 NT(Nano technology)를 접목시키는 기술이다. 특히, 이들을 종합한 MEMS에 관한 연구는 가장 광범위한 분야에서 활발하게 이루어지고 있어 그 기술적 가치가 점차 중요시되고 있다 본 연구는 Simulation을 통하여 Bio-MEMS기술에서 사용되는 미세Pump 내에서의 유체흐름을 Fluent 프로그램을 사용하여 알아보고자 하였다. 즉, 미세Pump 내로 유체가 흐를 경우, 유체의 압력변화나 온도 변화 및 Model에 따른 유동의 흐름을 관찰하여 미세pump 내에서의 최적의 외부조건과 최적의 Pump모델을 알아보고자 실험하였다. 유동의 흐름을 조사해 본 결과 Chamber의 유무에 따라 압력과 온도의 변화를 관찰할 수 있었다. Chamber가 있는 경우 압력의 변화가 적었고 온도의 변화 또한 적었다. 따라서 Chamber가 있는 Pump가 유체의 흐름에 영향을 적게 줌을 알 수 있었으며 이는 Chamber가 있는 Pump를 설계하는 것이 필요하다고 할 수 있다.