• 대한본초학회지
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• 제23권3호
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• pp.103-112
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• 2008

Objectives : This research aimed to study the cytotoxicity and immuno modulating activity of fermented Artemisia argyi Lev. et Vant.(Compositae). Methods : Effect of fermented Artemisiae Argyi Folium extracts, which were fermented by Sacchromyces cerevisiae STV89(AFS), on cell viability, generation of ROS within cells, generation of NO and the level of cytokines($TNF-{\alpha}$ and IL-6) was measured using mouse macrophage RAW 264.7 cell. Results : 1. Result of MTT assay conducted to verify the cytotoxicity of fermented Artemisiae argyi folium extract illustrated that, when fermented Artemisiae argyi folium extract was processed for each concentration, there was no excessive induction of cytoxicity in the RAW 264.7 cell. 2. Fermented Artemisiae Argyi Folium extract increased the generation of H2O2 within RAW 264.7 cell as well as significantly increased inhibition of generation of H2O2 in macrophage induced by LPS. 3. Fermented Artemisiae Argyi Folium extract inhibited generation of NO in RAW 264.7 cell, and significantly inhibited increase in generation of NO of macrophage induced by LPS. 4. Fermented Artemisiae Argyi Folium extract, AFS has significantly reduced the increase in the generation of $TNF-{\alpha}$ above 10 ${\mu}g/mL$. 5. Fermented Artemisiae Argyi Folium extract, AFS has significantly reduced the increase in generation of IL-6 above 50 ${\mu}g/mL$. Conclusions : AFS fermented extract produced from Artemisiae Argyi Flium, have increased generation of ROS and reduced generation of NO in RAW 264.7 cell without excessively inducing cytotoxicity of RAW 264.7 cell. In addition, they displayed significant immuno modulating activities including inhibition of generation of $TNF-{\alpha}$ and IL-6 in macrophage, induced by LPS.

• Asian-Australasian Journal of Animal Sciences
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• 제24권6호
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• pp.857-866
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• 2011

This study examined the metabolism of free radicals in hepatic mitochondria of goats induced by lipopolysaccharide (LPS), and investigated the effects of melatonin (MT). Forty-eight healthy goats ($10{\pm}1.2\;kg$) were randomly selected and divided into four groups: saline control, LPS, MT+LPS and MT. The goats within each group were3 sacrificed either 3 or 6 h after treatment and the livers removed to isolate mitochondria. The respiration control ratio (RCR), the ADP:O ratio, the oxidative phosphorylation ratio (OPR), the concentration of $H_2O_2$ and the activities of Complex I-IV were determined. The mitochondrial membrane potential ($\Delta\psi_m$) was analyzed by flow cytometry. The results showed that RCR, O/P and OPR of the LPS group decreased (p<0.05), as well as activities of respiratory complexes, whereas the generation of $H_2O_2$ in Complex III increased (p<0.05) after 3 h, while Complex II and III increased after 6 h. Also, it was found that the mitochondrial membrane potential of the LPS group declined (p<0.05). However, pre-treatment with MT attenuated the injury induced by LPS, which not only presented higher (p<0.05) RCR, O/P, OPR, and respiratory complex activities, but also maintained the $\Delta\psi_m$. Interestingly, it is revealed that, in the MT+LPS group, the generation of $H_2O_2$ increased firstly in 3 h, and then significantly (p<0.05).decreased after 6 h. In the MT group, the function of mitochondria, the transmenbrane potential and the generation of $H_2O_2$ were obviously improved compared to the control group. Conclusion: melatonin prevents damage caused by LPS on hepatic mitochondria of goats.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.240.2-240.2
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• 2013

The device scale of flash memory was confronted with quantum mechanical limitation. The next generation memory device will be required a break-through for the device scaling problem. Especially, graphene is one of important materials to overcome scaling and operation problem for the memory device, because ofthe high carrier mobility, the mechanicalflexibility, the one atomic layer thick and versatile chemistry. We demonstrate the hybrid memory consisted with the metal-oxide quantum dots and the mono-layered graphene which was transferred to $SiO_2$ (5 nm)/Si substrate. The 5-nm thick secondary $SiO_2$ layer was deposited on the mono-layered graphene by using ultra-high vacuum sputtering system which base pressure is about $1{\times}10^{-10}$ Torr. The $In_2O_3$ quantum dots were distributed on the secondary $SiO_2$2 layer after chemical reaction between deposited In layer and polyamic acid layer through soft baking at $125^{\circ}C$ for 30 min and curing process at $400^{\circ}C$ for 1 hr by using the furnace in $N_2$ ambient. The memory devices with the $In_2O_3$ quantum dots on graphene monolayer between $SiO_2$ thin films have demonstrated and evaluated for the application of next generation nonvolatile memory device. We will discuss the electrical properties to understating memory effect related with quantum mechanical transport between the $In_2O_3$ quantum dots and the Fermi level of graphene layer.

• 한국미생물·생명공학회지
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• 제28권1호
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• pp.1-7
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• 2000

The bacterial strain JW-2 which conferred resistance against paraquat (1,1'-dimethyl-4,4'-bipyridinium dichloride) was isolated from soil. The strain was identified as an Ochrobactrum anthropi based on its morphological, physiological, biological and fatty acid composition, and was designated as Ochrobactrum anthropi JW-2. We compard paraquat resistance of O. anthropi JW-2 with Escherichia coli J105. In the presence of 100mM paraquat, E. coli JM105 was not grown whereas the growth rate of O. anthropi was about 70% of control. We compared the sensitivity of O. anthropi JW-2 and E. coli J105 to redox-cycling compounds such as paraquat, plumbagin or menadione, which are known to exacebate wuperoxide generation. O. anthropi JW-2 did not show cross-resistance to plumbagin or menadione. superoxide dismutase activity was increased in paraqunt-treated E. coli JM105 while it was not increased in O.anthropi JW-2. These results suggest that the mechanism of paraquat resistance in O.anthropi JW-2 is probably due to selectively decreased permeability toward paraquat by membrane protein.

• 대한환경공학회지
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• 제34권11호
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• pp.715-719
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• 2012

단위면적당($cm^2$) 루테늄의 코팅량이 1.5 mg, 2.5 mg, 3.5 mg, 5.5 mg, 8.5 mg의 $RuO_2$/Ti 전극을 제조하여 코팅량에 따른 전기화학적 특성 차이와 염소 발생에 미치는 영향을 조사하였다. 순환전압 실험 결과 루테늄이 코팅된 전극의 염소 발생 과전압은 약 1.15 V (vs. Ag/AgCl)로 거의 일정하였다. 그러나 교류 임피던스 분광법, 동전위분극실험 결과 단위면적당($cm^2$) 루테늄의 코팅량이 2.5 mg, 3.5 mg $RuO_2$/Ti 전극의 저항은 각각 $0.4582{\Omega}$, $0.5267{\Omega}$, 부식속도는 각각 0.082 mm/yr, 0.058 mm/yr로 내구성이 가장 우수하였다. 염소 발생량은 단위면적당($cm^2$) 루테늄의 코팅량 3.5 mg 전극이 15.2 mg/L로 가장 높게 측정되었다.

• 한국환경과학회지
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• 제18권11호
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• pp.1235-1245
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• 2009

The purpose of this study is to investigate electro-generation of free Cl, $ClO_2$, $H_2O_2$ and $O_3$ and degradation of Rhodamine B in solution using Ru-Sn-Sb electrode. Electrolysis was performed in one-compartment reactor using a dimensionally stable anode(DSA) of Ru-Sn-Sb/Ti as the working electrode. The effect of applied current (0.5-3 A), electrolyte type (NaCl, KCl, HCl, $Na_2SO_4$ and $H_2SO_4$) and concentration (0.5-2.5 g/L), air flow rate (0-3 L/min) and solution pH (3-11) was evaluated. Experimental results showed that concentration of 4 oxidants was increased with increase of applied current, however optimum current for RhB degradation was 2 A. The generated oxidant concentration and RhB degradation of the of Cl type-electrolyte was higher than that of the sulfate type. The oxidant concentration was increased with increase of NaCl concentration and optimum NaCl dosage for RhB degradation was 1.75 g/L. Optimum air flow rate for the oxidants generation and RhB degradation was 2 L/min. $ClO_2$ and $H_2O_2$ generation was decreased with the increase of pH, whereas free Cl and $O_3$ was not affected by pH. RhB degradation was increase with the pH decrease.

• 마이크로전자및패키징학회지
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• 제13권2호
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• pp.15-19
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• 2006

이원계 산화막인 비정질 $SiO_2$와 다결정 $TiO_2$의 저항 변화 특성을 연구하였다. Metal-Insulator-Metal의 저항 소자를 형성하여 전압 sweep에 의한 I-V를 측정하여 저항 상태를 확인하였다. 즉, 낮은 저항 상태 (LRS) 와 높은 저항 상태 (HRS) 의 두 가지 저항 상태가 존재하였으며, LRS는 전압에 의한 절연체의 불완전한 breakdown 후에, HRS는 전압에 의한 negative differential resistance 후에 각각 나타났다. LRS의 경우에는 Ohmic 전도 mechanism에 의해서, HRS의 경우에는 Schottky contact에 의한 potential barrier의 생성이 저항 상태를 결정한다고 제안하였다. 즉, potential barrier의 생성과 소멸이 두 저항 상태를 형성한다고 할 수 있다. 유전율이 높은 $TiO_2$가 $SiO_2$에 비하여, 낮은 동작 특성 전압을 나타내었으며, 1 V에서의 저항비도 높았다.

• Natural Product Sciences
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• 제19권1호
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• pp.54-60
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• 2013

Rhus verniciflua Stokes (Anacadiaceae) is a plant that is native to East Asian countries, such as Korea, China, and Japan, and it has been found to exert various biological activities including antioxidative, anti-aggregatory, anti-inflammatory, anti-mutagenic, and apoptotic effects. Sulfuretin is one of the major flavonoid component isolated from the heartwood of R. verniciflua. Reactive oxygen species (ROS), produced via dental adhesive bleaching agents and pulpal disease, can cause oxidative stress. In the present study, we isolated sulfuretin from R. verniciflua and demonstrated that sulfuretin possesses cytoprotective effects against hydrogen peroxide ($H_2O_2$)-induced dental cell death. $H_2O_2$ is a representative ROS and causes cell death through necrosis in human dental pulp (HDP) cells. $H_2O_2$-induced cytotoxicity and production of ROS were blocked in the presence of sulfuretin, and these effects were dose dependent. Sulfuretin also increased heme oxygenase-1 (HO-1) protein expression. In addition, to determine whether sulfuretin-induced HO-1 expression mediated this cytoprotective effect, HDP cells were cotreated with sulfuretin in the absence or presence of SnPP, an inhibitor of HO activity. Sulfuretin-dependent HO-1 expression was required for suppression of $H_2O_2$-induced HDP cell death and ROS generation. These results indicate that sulfuretin-dependent HO-1 expression was required for the inhibition of $H_2O_2$-induced cell death and ROS generation. In addition, sulfuretin may be used to prevent functional dental cell death and thus may be useful as a pulpal disease agent.

• 대한한방내과학회지
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• 제41권1호
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• pp.44-58
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• 2020

Objectives: This study was conducted to identify the protective effects of Chongmyunggongjin-dan (CMGJD) on Hydrogen peroxide (H₂O₂)-induced apoptosis mechanisms in C6 glial cells. Method: We used CMGJD after distilled water extraction, filtration, and lyophilization. The ROS scavenging effect was examined by fluorescence microscopy. Expression levels of proteins related to ROS generation were investigated by western blotting. Functional changes in organelles related to Reactive oxygen species (ROS) generation were investigated by immunoblotting and by verifying expression level of relevant enzymes. Results: The CMGJD extract protected the cells against H₂O₂-induced morphological changes and DNA fragmentation, inhibited the increase of Heme_oxygenase-1(HO^-1) and the decrease in catalase, protected against the loss of mitochondrial membrane potential, inhibited disturbances of lysosomal function, and induced an increase in peroxisomes. Conclusion: CMGJD was confirmed to have a protective effect on H₂O₂-induced C6 glial cell death possibly by blocking the pathways causing damage to subcellular organelles, such as mitochondria, lysosomes, and peroxisomes. We assume that CMGJD will be effective for the prevention and treatment of ischemic stroke in a clinical environment.

• 한국세라믹학회지
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• 제27권2호
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• pp.169-178
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• 1990

The sintering characteristics of ZrO2 were analyzed in terms of pore microstructure and kinetics of pore elimination. The pore structue of the ZrO2 sample prepared from colloid suspension was characterized by three distinct types of pores ; intradomain, interdomain, and intergglomerate pores. Sintering data at 1600$^{\circ}C$ showed that pores larger than a certain critical size(∼3$\mu\textrm{m}$) were difficult to remove, and this was analyzed in terms of the interagglomerate pore formed from the suspension under the condition of low kinetic stability, that is, the stability ratio smaller than its critical value. A theoretical equation for densification rate was derived and was applied to the densification rate of the ZrO2 polycrystalline body containging both the matrix(the 1st-generation) pores and the interagglomerate (the 2nd-generation) pores under the condition of slow grain growth.