• Journal of Periodontal and Implant Science
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• 제37권4호
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• pp.655-669
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• 2007

Reactive oxygen species (ROS) have been implicated in the pathogenesis of various diseases. And vitamin C has shown a protective effect for the tissues. The aim of this study was to evaluate the effects of $H_2O_2$ and ascorbic acid on matrix metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinase (TIMP: TIMP-1, TIMP-2), Type 1 collagen, fibronectin, and PDLs22 level in human periodontal ligament fibroblasts (hPDLF) via reverse transcription-polymerase chain reaction (RT-PCR). hPDLF was obtained from a healthy periodontium and cultured in Dulbecco's modified Eagles's medium plus 10% fetal bone serum. The concentration of ascorbic acid in hPDLF was $50{\mu}g/ml$, and that of $H_2O_2$ in hPDLF was 0.03% and 0.00003%. Ascorbic acid only, $H_2O_2$ only and mixture of ascorbic acid and $H_2O_2$ were applied with hPDLF for 1-, 3-, and 30-min. respectively. The gene expression of MMP-1-, TIMP-1-, TIMP-2-, Type 1 collagen-, fibronectin-, and PDLs22-mRNA in hPDLF was analysed via RT-PCR. The results were as follows; 1. hPDLF in response to 30-min. incubation with 0.03% $H_2O_2$ did not show any gene expression. 2. In all the experimental groups, the gene expression of fibronectin mRNA showed the decreased tendency compared to control. 3. In all the experimental groups, the gene expression of TIMP-1 mRNA showed the tendency similar to control. 4. hPDLF in response to 30-min. incubation with 0.03% $H_2O_2$ and ascorbic acid increased mRNA induction for MMP-1. 5. In all the experimental groups, hPDLF increased mRNA induction for PDLs22, collagen type 1, and TIMP-2 compared to control. Within the limited experiments, $H_2O_2$ and ascorbic acid increased mRNA induction for PDLs22, collagen type 1, TIMP-2 in hPDLF. More research will be needed in order to confirm the relative importance of the different roles of ROS and antioxidants in hPDLF from a periodontal regeneration or repair standpoint.

• 상하수도학회지
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• 제32권3호
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• pp.261-268
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• 2018

Sludge transporting pipes in wastewater treatment plant are easy to be clogged with struvite when the digested sludge and dehydrated filtrate are transported through the pipes, which lowers the efficiency of sludge treatment system in a WWTP. pH is one of the most important factors in struvite formation, and carbon dioxide separated from biogas can be used to control pH and struvite formation. By controlling pH, the amount of dehydrating agent can be reduced by about 10%, which saves the budget for facility maintenance. As $CO_2$ is reused and dehydrating chemicals are saved, the approach can contribute to global warming gas reduction.

• 대한기계학회논문집A
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• 제26권2호
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• pp.399-405
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• 2002

This paper proposes a new type of piezoactuator-driven valve system. The piezoceramic actuator bonded to both sides of a flexible beam surface makes a movement required to control the pressure at the flapper-nozzle of a pneumatic valve system. After establishing a dynamic model, an appropriate size of the valve system is designed and manufactured. Subsequently, a robust H$_{\infty}$ control algorithm is formulated in order to achieve accurate tracking control of the desired pressure. The controller is experimentally realized and control performance for the sinusoidal pressure trajectory is presented in time domain. The control bandwidth of the valve system, which directly represents the fastness, is also evaluated in the frequency domain.

• 약학회지
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• 제48권1호
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• pp.93-98
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• 2004

The purpose of this study was to evaluate the effect of pharbitidis seed extract (PE) on antioxidant enzymes. The cytotoxicities of PE were measured by 3- (4,5-dimethlthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; The change of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activity assay were measured. The SOD activities by PE-treated groups were lower than control group's one. In the co-treated with hydrogen peroxide ($H_2O$$_2$) group, SOD activity was higher than $H_2O$$_2$ treated group's activity In the case of GPx, GPx activities were increased in both PE-treated and co-treated with $H_2O$$_2$ group. In the case of CAT $H_2O$$_2$ treated group's activityies were very increased. The CAT activities by PE-treated groups were lower than control group's one, but the activity of co-treated group with H $_2$O$_2$ was higher than that of control group's one. These results suggest that PE has antioxidant activity.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.66-70
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• 1991

A mixed $H_{2}$ / H.inf. design methodology is suggested for a single-input-single-output system. Suboptimal $H_{2 }$ controllers stabilizing the closed loop system under the additive uncertainty are obtained. An extended Nevanlinna-Pick algorithm is used to obtain the suboptimal. controllers.s.

• Applied Microscopy
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• 제32권4호
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• pp.399-410
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• 2002

죽력의 투여에 따른 생쥐 간세포의 항산화효소 활성변화와 간과 신장의 조직병리학적 변화에 미치는 영향을 통하여 치료약물로써 죽력의 안전성 확보에 기여하고자 본 연구를 수행하였다. 대조군은 생리식염수를 투여하였으며, 실험군은 죽력을 생리식염수에 5% (H1군), 10% (H2군), 20% (H3군)로 희석하여 0.2 ml씩 48시간 간격으로 28일 동안 구강 투여하였다. 대조군과 실험군의 간조직을 절취하여 SOD와 catalase의 활성변화를 측정하였으며, 간과 신장의 조직학적변화 및 미세구조적 변화를 관찰하였다. MnSOD의 활성은 대조군에 비하여 H1 (46%, P<0.05), H2 (40%, P<0.05), H3군 (34%, P<0.05)에서 증가하였다 (Fig. 1). CuZnSOD의 활성은 대조군에 비하여 H1군 (11%, P<0.05)에서는 증가하였으나, H3군 (13%, P<0.05)에서는 감소하였다. Catalase의 활성은 대조군에 비하여 H1 (39%, P<0.05), H2 (34%, P<0.05), H3군 (31%, P<0.05)에서 감소하였다. 간과 신장의 조직병리학적 관찰 결과, H3군에서 간세포의 팽창과 중심정맥 내피세포의 파괴현상이 뚜렷이 나타났으며, 신장의 곱슬세관 상피세포의 파괴현상이 뚜렷하였다. H2군의 간세포는 핵질이 매우 응축되어 있었으며, 사립체의 팽대현상이 현저하였다. H3군은 핵질의 전자밀도가 매우 낮게 나타났다. 사립체의 내강은 매우 팽대되어 있고 크리스테의 형태는 관찰되지 않으면서 기질의 전자밀도는 낮게 나타났다. H3군 근위곱슬소관의 원주상피세포는 핵의 괴사가 뚜렷하였으며, 세포질내에서 관찰되는 사립체들은 대부분 팽대되거나 파괴된 양상을 보여주었다. 이상의 연구 결과로 보아 죽력은 투여 농도에 따라 간세포의 항산화효소 활성의 변화와 간과 신장의 조직 병리학적 변화를 초래한다고 생각된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1298-1300
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• 1994

An ability of $NO_2$ gas detection has been investigated using dilithium phthalocyanine($Li_2Pc$) Langmuir-Blodgett (LB) films. It is a well-known gas sensitive material and has been manufactured under a surface pressure of 30mN/m. A status of deposited films was confirmed by UV-visible absorption spectrum, ellipsometry measurements and current-voltage characteristics. Gas-detection characteristics of the films were studied through an electrical conductivity, response time, recovery time, and reproducibility under 200 ppm of $NO_2$ gases.

• KSBB Journal
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• 제14권5호
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• pp.628-632
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• 1999

에리스리톨을 산업적으로 대량생산하기 위해서는 에리스리톨의 생산성을 높이고 부산물인 글리세롤의 생성을 억제하는 배지 및 발효 공정의 최적화가 필요하다. 에리스리톨 생성을 위한 최적 탄소원은 포도당이고 최적 농도는 400 g/L이며 최적 온도는 3$0^{\circ}C$였으며 이 때 산소는 과잉으로 공급해 주어야 함을 알았다. 에리스리톨의 수율과 생산성을 향상시키기고 배지가격을 줄이기 위해 효모 추출물의 사용을 5 g/L에서 3 g/L로 줄이고 urea 2.72g/L$K_2HPO_4$ 1.79 g/L, MgSO$_4$. $7H_2O$ 0.18 g/L를 첨가해 줌으로써 에리스리톨 수율을 31.4%에서 45.2%로 에리스리톨 생산성을 0.747 g/L/h에서 1.071 g/L/h로 향상시켰다. 또한 글리세롤의 생산량도 96.6 g/L에서 45.7 g/L로 줄었다. 이 최적 배지를 바탕으로 5L 발효기에서의 재현성과 pH에 대한 영향을 알아보기 위해 실험을 한 결과 pH를 조절한 경우에 에리스리톨 생산성이 낮아졌다. 5L 발효에서는 다량의 거품이 발생되는 것을 관찰하였다.

• 한국축산식품학회지
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• 제21권3호
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• pp.200-207
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• 2001

Effects of dietary chitosan on physico-chemical properties of pork were investigated. A total 24 pigs (55$\pm$5kg) were fed a control diet (a commercial feed) or chitosan-supplemented diets (T1: 0.2% chitosan, T2: 0.4% chitosan, T3: 0.6% chitosan) for 6 weeks. The 6 weeks later the initiated of the experiments, pigs were slaughtered and loins were collected from each treatment groups. The samples were stored at 0$\pm$1$^{\circ}C$ for 15 days. Ultimate pH tended to higher in the control than those in the treatments, and that of T3 was significantly lower than those of the others (P<0.05). Shear force and the total moisture contents were not significantly different between control and treatments and they decreased with storage days (P<0.05). Hunter L* values of control, T1 and T2 were significantly lower than that of T3 at 1 and 10 days (P<0.05). Hunter a* values of control were significantly higher than that of others at 1 and 5 days (P<0.05). Hunter b* values of control were significantly higher than that of others at 5 days (P<0.05).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2076-2080
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• 2005

Study in this paper concerns the optimal $H_{2}$ integral servo problems for linear crane model systems via the constraints of the derivatives of state variables added to the standard constraints. It is shown in the paper that the derivative state constrained optimal $H_{2}$ integral servo problems can be reduced to the standard optimal $H_{2}$ control problem. The main subject of the paper is to apply the results of derivative state constrained $H_{2}$ integral servo theorem in crane system. The effect of our proposed controller with respect to mitigate an under damping for crane model system is also verified.