• 농약과학회지
• /
• 제9권3호
• /
• pp.191-198
• /
• 2005

신규 살충제 표적 단백질인 AnCE의 활성부위 잔기들과 상호작용 가능한 약리단 (pharmacophore)을 세 개의 펩타이드로 이루어진 ACE 기질 Hippuryl-L -histidyl-L-leucine (Hip-L-His-L-Leu, HHL) 분자의 구조를 모델로 하여 예측하였다. HHL의 분자구조, 용액장 내에서의 구조변화 그리고 약리단을 구성하는 원자들의 전하밀도 분석을 위해 순이론적인 양자화학 계산방법을 이용하여 구조 최적화, NMR 화학적 이동 및 NPA 계산을 수행하였다. 이론적인 NMR 화학적 이동 값들은 실험 결과와 잘 일치함을 보였고 전하밀도 계산 결과는 해당원자의 약리단을 분석하는데 사용되었다. 결과적으로 HHL 분자 구조를 통해 소수성(aromatic, aliphatic), 수소결합 주게, 수소결합 받게, 금속 아연 결합부위의 5개 약리단을 추출할 수 있었다.

• 동의생리병리학회지
• /
• 제22권5호
• /
• pp.1262-1269
• /
• 2008

Low intensity pulsed ultrasound(LIPUS) is known to accelerate bone regeneration, but the precise cellular signaling mechanism is still unclear. The purpose if this study was to determine the effect of LIPUS on the signaling mechanism of rat chondrocyte. In the explant culture condition, there was inhibition effect of 1 $W/cm^2$ intensity LIPUS on chondrocytes proliferation but chondrocytes proliferation was increased at 0.25 $W/cm^2$ intensity. In addition, western blot analysis of MAPKs showed that LIPUS increased ERK1/2 activity from the 10 min treatment of LIPUS. Hydrogen peroxide($H_2O_2$), resulted in a time- and dose-dependent cell proliferation, which was largely attributed to apoptosis. $H_2O_2$ treatment caused marked sustained nucleus condensation in Hoechst stain. LIPUS and $H_2O_2$ activates phosphorylation of p-ERK1/2 and PD 98059($10^{-5}M$) blocked the effect of LIPUS and $H_2O_2$. Moreover, the synergistic phosphorylation of p44/42 MAPK by $H_2O_2$, LIPUS was selectively inhibited by PD 98059, ERK1/2 inhibitor. In order to determine whether the increase in cell proliferation caused by $H_2O_2$ and LIPUS could be explained by changes in the level of the prostaglandin $E_2$. Our study demonstrated that LIPUS stimulate the cell proliferation via activated phosphorylation of ERK1/2 in condrocyte. LIPUS has anabolic effects on rat cartilage in explant cultures, indicating a potential important method for the treatment of osteoarthritic cartilarge.

• Biomolecules & Therapeutics
• /
• 제16권1호
• /
• pp.14-20
• /
• 2008

In the present study, we examined how the transport of choline is regulated at the blood-brain barrier (BBB) under the central nervous system (CNS) cellular damages by oxidative stress using a conditionally immortalized rat brain capillary endothelial cells (TR-BBB), in vitro the BBB model. It was also tested whether the choline uptake is influenced by membrane potential, extracellular pH, protonophore (FCCP) and amiloride in TR-BBB cells. In result, $[^3H]choline$ uptake was inhibited by FCCP and dependent on extracellular pH. The treatment of TR-BBB cells with 20 ng/mL tumor necrosis $factor-{\alpha}$ $(TNF-{\alpha})$, 10 ng/mL lipopolysaccharide (LPS), 100 ${\mu}M$ diethyl maleate (DEM) and 100 ${\mu}M$ glutamate resulted in 3.0-fold, 2.6-fold, 1.8-fold and 2.0-fold increases of $[^3H]choline$ uptake at the respective peak time, respectively. In contrast, hydrogen peroxide and raffinose did not show any significant effects on choline uptake. In addition, choline efflux was significantly inhibited by $TNF-{\alpha}$, LPS and DEM producing cell damage states. In conclusion, the influx and efflux transport system for choline existed in TR-BBB cell line and this process was affected by several oxidative stress inducing agents.

• Biomolecules & Therapeutics
• /
• 제25권6호
• /
• pp.599-608
• /
• 2017

Tanshinone IIA (Tan IIA) is a pharmacologically active substance extracted from the rhizome of Salvia miltiorrhiza Bunge (also known as the Chinese herb Danshen), and is widely used to treat atherosclerosis. The pregnane X receptor (PXR) is a nuclear receptor that is a key regulator of xenobiotic and endobiotic detoxification. Tan IIA is an efficacious PXR agonist that has a potential protective effect on endothelial injuries induced by xenobiotics and endobiotics via PXR activation. Previously numerous studies have demonstrated the possible effects of Tan IIA on human umbilical vein endothelial cells, but the further mechanism for its exerts the protective effect is not well established. To study the protective effects of Tan IIA against hydrogen peroxide ($H_2O_2$) in human umbilical vein endothelial cells (HUVECs), we pretreated cells with or without different concentrations of Tan IIA for 24 h, then exposed the cells to $400{\mu}M$ $H_2O_2$ for another 3 h. Therefore, our data strongly suggests that Tan IIA may lead to increased regeneration of glutathione (GSH) from the glutathione disulfide (GSSG) produced during the GSH peroxidase-catalyzed decomposition of $H_2O_2$ in HUVECs, and the PXR plays a significant role in this process. Tan IIA may also exert protective effects against $H_2O_2$-induced apoptosis through the mitochondrial apoptosis pathway associated with the participation of PXR. Tan IIA protected HUVECs from inflammatory mediators triggered by $H_2O_2$ via PXR activation. In conclusion, Tan IIA protected HUVECs against $H_2O_2$-induced cell injury through PXR-dependent mechanisms.

• 공업화학
• /
• 제4권2호
• /
• pp.318-323
• /
• 1993

CFC-11$(CFCl_3)$의 대체품인 HCFC-123$(CF_3CHCl_2)$의 합성을 위하여 Pentachloroethane($CHCl_2CCl_3$)을 제조하고, 이것을 antimony pentahalide 촉매의 존재하에서 불화수소와 반응시켰다. $CHCl_2CCl_3$의 불소화 반응은 촉매와 반응물간의 Cl-F교환 mechanism에 의해 진행되었으며 $CHCl_2CCl_3$의 불화도는 반응온도가 높을수록 증가하는 경향을 보여 주었다. 촉매농도 또한 생성물의 불화도에 영향을 미치나 반응온도에 비해 상대적으로 낮았다. $CCl_3CFCl_2$, $CFCl_2CFCl_2$, $CF_2ClCFCl_2$와 같은 부산물의 생성원인을 규명하기 위한 실험을 실시하여 부산물 생성 mechanism을 제안하였다.

• 상하수도학회지
• /
• 제25권2호
• /
• pp.223-230
• /
• 2011

An electrolytic oxidation process was applied to remove odorous compounds from non-point odor sources including wastewater pipelines and manholes. In this study, a distance between the anode and the cathode of the electrolytic process was varied as a system operating parameters, and its effects on odor removal efficiencies and reaction characteristics were investigated. Odor precursors such as sediment organic matters and reduced sulfur/nitrogen compounds were effectively oxidized in the electrolytic process, and a change in oxidation-reduction potential (ORP) indicated that an stringent anaerobic condition shifted to a mild anoxic condition rapidly. At an electrode distance of 1 cm and an applied voltage of 30 V, a system current was maintained at 1 A, and the current density was 23.1 $mA/cm^{2}$. Under the condition, the removal efficiency of hydrogen sulfide in gas phase was found to be 100%, and 93% of ammonium ion was removed from the liquid phase during the 120 minute operating period. Moreover, the sulfate ion (${SO_4}^{2-}$) concentration increased about three times from its initial value due to the active oxidation. As the specific power consumption (i.e., the energy input normalized by the effective volume) increased, the oxidation progressed rapidly, however, the oxidation rate was varied depending on target compounds. Consequently, a threshold power consumption for each odorous compound needs to be experimentally determined for an effective application of the electrolytic oxidation.

• 방사성폐기물학회지
• /
• 제9권4호
• /
• pp.231-236
• /
• 2011

지난 2011년 3월의 후쿠시마 원전 사고시 원자로 건물에서의 연쇄적인 수소폭발이 발생하였을 때 관계자들은 제1원전 4호기의 폭발에 더욱 놀랐었는데 이는 그 당시 4호기는 정기보수를 위하여 원자로내 모든 핵연료를 저장조에 보관중이었기 때문이다. 저장조내 냉각수 유실로 노심에서 옮겨진 핵연료가 공기 중에 노출되어 수소가 발생하고 임계가 도달하였다면 더욱 심각할 수도 있기 때문이었는데 다행히 추후에 양호한 냉각수 상태가 확인되어 우려할 상황을 피할 수 있었다. 본 논문에서는 후쿠시마 원전 사고를 계기로 국내 원자력 발전소내 핵연료 임시 저장시설의 안전성과 관련하여 중대사고 관점에서 검토해 보고자 한다.

• 한국재료학회지
• /
• 제27권3호
• /
• pp.137-143
• /
• 2017

Boron-doped diamond (BDD) electrode has an extremely wide potential window in aqueous and non-aqueous electrolytes, very low and stable background current and high resistance to surface fouling due to weak adsorption. These features endow the BDD electrode with potentially wide electrochemical applications, in such areas as wastewater treatment, electrosynthesis and electrochemical sensors. In this study, the characteristics of the BDD electrode were examined by scanning electron microscopy (SEM) and evaluated by accelerated life test. The effects of manufacturing conditions on the BDD electrode were determined and remedies for negative effects were noted in order to improve the electrode lifetime in wastewater treatment. The lifetime of the BDD electrode was influenced by manufacturing conditions, such as surface roughness, seeding method and rate of introduction of gases into the reaction chamber. The results of this study showed that BDD electrodes manufactured using sanding media of different sizes resulted in the most effective electrode lifetime when the particle size of alumina used was from $75{\sim}106{\mu}m$ (#150). Ultrasonic treatment was found to be more effective than polishing treatment in the test of seeding processes. In addition to this, BDD electrodes manufactured by introducing gases at different rates resulted in the most effective electrode lifetime when the introduced gas had a composition of hydrogen gas 94.5 vol.% carbon source gas 1.6 vol.% and boron source gas 3.9 vol.%.

• 한국독성학회:학술대회논문집
• /
• 한국독성학회 2001년도 International Symposium on Dietary and Medicinal Antimutgens and Anticarcinogens
• /
• pp.159-160
• /
• 2001

Gap junctional intercellular communication (GJIC) is a cellular event underlying the tumor promotion process and that treatment to prevent the down-regulation or to up-regulate GJIC is important in preventing tumor promotion. We evaluated the potential preventive effect of Mushroom Phellinus Linteus (PL) against the promoting action of hydrogen peroxide ($H_2O$$_2$) in WB-F344 rat liver epithelial cells.(omitted)

• 한국물환경학회지
• /
• 제33권6호
• /
• pp.689-695
• /
• 2017

This study was carried out to investigate the physicochemical and adsorptive characteristics of black carbon (BC) materials for cesium in case of severe nuclear accidents. The BC was prepared with a xylem of oak and pine trees incompletely combusted with different ramp rate and final temperature. Carbon (C), hydrogen (H) and oxygen (O) atomic ratios, BET, pore structure, and zeta potential were characterized for the produced BC. A low cesium concentration ($C_w{\approx}10^{-7}M$) was used for sorption batch experiments. The H/C and O/C ratios of BC decreased with the increase of final temperature, which indicates a carbonization of the wood materials regardless of ramp rate and tree species. However, SEM images showed different pore structures depending on tree species such as steric and plate-like for oak-BC and pine-BC, respectively. The greatest sorption distribution coefficients of $K_{d,Cs}{\approx}1,200{\sim}1,800L\;kg^{-1}$ were observed for the oak-BC produced at $400^{\circ}C$, while comparatively low $K_{d,Cs}$ < $100L\;kg^{-1}$ for pine-BC. In addition, the sorption capabilities of BC declined with the increase of combustion temperature up to $600^{\circ}C$, because high temperature destroyed surface functionalities with the rise of ash components in the BC. Therefore, the sorption processes of BC for radioactive cesium are predominantly controlled by final production temperature of BC as well as raw materials (e.g., tree species).