• International Journal of Oral Biology
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• v.37 no.1
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• pp.17-23
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• 2012

Recent studies indicate that reactive oxygen species (ROS) are critically involved in persistent pain primarily through spinal mechanisms, and that mitochondria are the main source of ROS in the spinal dorsal horn. To investigate whether mitochondrial ROS can induce changes in membrane excitability on spinal substantia gelatonosa (SG) neurons, we examined the effects of mitochondrial electron transport complex (ETC) substrates and inhibitors on the membrane potential of SG neurons in spinal slices. Application of ETC inhibitors, rotenone or antimycin A, resulted in a slowly developing and slight membrane depolarization in SG neurons. Also, application of both malate, a complex I substrate, and succinate, a complex II substrate, caused reversible membrane depolarization and enhanced firing activity. Changes in membrane potential after malate exposure were more prominent than succinate exposure. When slices were pretreated with ROS scavengers such as phenyl-N-tert-buthylnitrone (PBN), catalase and 4- hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL), malate-induced depolarization was significantly decreased. Intracellular calcium above $100{\mu}M$ increased malateinduced depolarization, witch was suppressed by cyclosporin A, a mitochondrial permeability transition (MPT) inhibitor. These results suggest that enhanced production of spinal mitochondrial ROS can induce nociception through central sensitization.

• BMB Reports
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• v.49 no.1
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• pp.45-50
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• 2016

Salsolinol (SAL), a compound derived from dopamine metabolism, is the most probable neurotoxin involved in the pathogenesis of Parkinson's disease (PD). In this study, we investigated the modification and inactivation of human ceruloplasmin (hCP) induced by SAL. Incubation of hCP with SAL increased the protein aggregation and enzyme inactivation in a dose-dependent manner. Reactive oxygen species scavengers and copper chelators inhibited the SAL-mediated hCP modification and inactivation. The formation of dityrosine was detected in SAL-mediated hCP aggregates. Amino acid analysis post the exposure of hCP to SAL revealed that aspartate, histidine, lysine, threonine and tyrosine residues were particularly sensitive. Since hCP is a major copper transport protein, oxidative damage of hCP by SAL may induce perturbation of the copper transport system, which subsequently leads to deleterious conditions in cells. This study of the mechanism by which ceruloplasmin is modified by salsolinol may provide an explanation for the deterioration of organs under neurodegenerative disorders such as PD. [BMB Reports 2016; 49(1): 45-50]

• International Journal of Oral Biology
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• v.40 no.2
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• pp.103-109
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• 2015

Growing evidence suggests that mitochondrial reactive oxygen species (ROS) are involved in various pain states. This study was performed to investigate whether ROS-induced changes in neuronal excitability in trigeminal subnucleus caudalis are related to ROS generation in mitochondria. Confocal scanning laser microscopy was used to measure ROS-induced fluorescence intensity in live rat trigeminal caudalis slices. The ROS level increased during the perfusion of malate, a mitochondrial substrate, after loading of 2',7'-dichlorofluorescin diacetate ($H_2DCF-DA$), an indicator of the intracellular ROS; the ROS level recovered to the control condition after washout. When pre-treated with phenyl N-tert-butylnitrone (PBN) and 4-hydroxy-2,2,6,6-tetramethylpiperidene-1-oxyl (TEMPOL), malate-induced increase of ROS level was suppressed. To identify the direct relation between elevated ROS levels and mitochondria, we applied the malate after double-loading of $H_2DCF-DA$ and chloromethyl-X-rosamine (CMXRos; MitoTracker Red), which is a mitochondria-specific fluorescent probe. As a result, increase of both intracellular ROS and mitochondrial ROS were observed simultaneously. This study demonstrated that elevated ROS in trigeminal subnucleus caudalis neuron can be induced through mitochondrial-ROS pathway, primarily by the leakage of ROS from the mitochondrial electron transport chain.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.16-16
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• 2023

기후변화로 인한 가뭄, 홍수, 녹조 등 이상기후 현상들이 본격화함에 따라 안정적인 수자원 관리의 필요성이 증가하고 있다. 특히 급변하는 환경조건 속에서도 안정적인 수자원 확보를 가능하게 하는 지하수 자원의 적극적인 활용은 기후변화대응에 있어 핵심적인 요소이다. 지하수는 하천, 호수 연안지역 등 다양한 지표의 수문환경과 연결되어 천층지권의 수문생태적 특성을 결정하기 때문에, 지속가능한 수자원 활용을 위해서는 지하수와 지표수의 상호작용에 대한 통합적인 검토가 이루어져야 한다. 하지만 긴밀하게 연계된 특성에도 불구하고 지하수와 지표수에 대한 연구는 오랜기간 개별수문환경에 대해 독립적으로 수행되어왔다. 이러한 연구경향은 저류시간이 크게 다른 지하수와 지표수의 수문적 특성뿐 아니라 개별수문환경에서 나타나는 작용들을 통합적으로 다룰 수 있는 모델의 부제에도 기인한다. 최근 비약적인 연산능력의 향상과 함께 지하수-지표수 환경을 연계한 통합수문모델(Integrated Hydrology Model)의 개발 및 활용이 이루어짐에 따라 기후변화 및 수자원 활용에 따른 수문환경변화 대한 통합적인 연구 시도가 이루어지고 있다. 본 발표에서는 최근의 통합수문모델과 다중요소 반응성 운송 모형(Multicomponent Reactive Transport Model)의 연계를 통한 물질순환 연구의 최신 동향을 소개하고(농도-유량 상관관계, 지표수계의 화학적 풍화와 이산화탄소 저감, 녹조 등), 데이터 기반 모형을 통한 통합수문모델의 연산 효율 및 정확성 향상을 위한 방법에 대해 모색하고자 한다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.195-198
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• 2002

Nitrogen pollution in urban and rural groundwater is a common problem and poses a major threat to drinking water supplies based on groundwater. In this work, the kinetics of nitrification-denitrification coupled reactions are modeled and new reaction modules for the RT3D code (Clement, 1997) describing the fate and transport nitrogen species, dissolved oxygen, dissolved organic carbon, and biomass are developed. The proposed nitrogen transformations and transport model showed very good match with results of a conceptual model. However, the model simulation results for the major reactive species should be tested for validation using experimental and field data.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.137-140
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• 2003

This study presents a mathematical model for simulating the fate and transport of a reactive organic contaminant degraded through cometabolism in dual-porosity soils during the in situ bioaugmentations. To investigate the effect of dual-porosity on transport and biodegradation of organic hydrocarbons, a bimodal approach was incorporated into the model. Modified Monod kinetics and a microcolony concept [Molz et at., 1986〕 were employed to represent the effects of biodegrading microbes on the transport and biodegradation of an organic contaminant. The effect of permeability reduction due to biomass accumulation on the flow field were examined in the simulation of a hypothetical field-scale in situ bioaugmentation. Simulation results indicate that the presence of the immobile region can decrease the bioavailablity of biodegradable contaminants and that the placement of microbes and nutrients injection wells should be considered for an effective in situ bioaugmentation scheme.

• Membrane and Water Treatment
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• v.14 no.2
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• pp.95-106
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• 2023

In the developing country like India, groundwater is the main sources for household, irrigation and industrial use. Its contamination poses hydro-geological and environmental concern. The hazardous waste sites such as landfills can lead to contamination of ground water. The contaminants existing at such sites can eventually find ingress down through the soil and into the groundwater in case of leakage. It is necessary to understand the process of migration of pollutants through sub-surface porous medium for avoiding health risks. On this backdrop, the present paper investigates the behavior of pollutants' migration through porous media. The laboratory experiments were carried out on a soil-column model that represents porous media. Two different types of soils (standard sand and red soil) were considered as the media. Further, two different solutes, i.e., non-reactive and reactive, were used. The experimental results are simulated through numerical modeling. The percentage variation in the experimental and numerical results is found to be in the range of 0.75- 11.23 % and 0.84 - 1.26% in case of standard sand and red soil, respectively. While a close agreement is observed in most of the breakthrough curves obtained experimentally and numerically, good agreement is seen in either result in one case.

• Journal of Acupuncture Research
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• v.19 no.4
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• pp.190-199
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• 2002

Objective : This study was performed to determine if Scutellaria balicalensis Georgi extract (SbGE) prevents oxidant-induced membrane transport dysfunction in renal tubular cells. Methods : Membrane transport function was estimated by measuring $Na^+$-dependent inorganic phosphate transport in opossum kidney (OK) cells. $H_2O_2$ inhibited phosphate transport in a dose-dependent manner. Results : The inhibitory effect of $H_2O_2$ was significantly prevented SbGE over concentration range of 0.005-0.05%. $H_2O_2$ caused ATP depletion, which was prevented by SbGE. $H_2O_2$ induced the loss of mitochondrial function as evidenced by decreased MTT reduction and its effect was prevented by SbGE. The $H_2O_2$-induced inhibition of phosphate transport was not affected by a potent antioxidant DPPD, but the inhibition was prevented by an iron chelator deferoxamine, suggesting that $H_2O_2$ inhibits $Na^+$-dependent phosphate transport via an iron-dependent nonperoxidative mechanism in renal tubular cells. Conclusion : These data suggest that SbGE may exert the protective effect against oxidant-induced membrane transport dysfunction by a mechanism similar to iron chelators in renal epithelial cells. However, furher studies should be carried out to find the active ingredient(s) of SbGE that exerts the protective effect.

• Journal of Soil and Groundwater Environment
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• v.20 no.5
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• pp.1-10
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• 2015

FeS, as a natural reduced iron mineral, has been recognized to be a viable reactive material for As(III) sequestration in natural and engineered systems. In this study, FeS-coated sand packed columns were tested to evaluate the As(III) removal capacities under anaerobic conditions at pH 5, 7 and 9. The column obtained As(III) removal capacity was then compared with the capacity result obtained from batch reactors. In the comparison, two different approaches were used. The first approach was used the total As(III) removal capacity which method was proved to be useful for interpreting pH 5 system. The second approach was used to consider sorption non-linearity and proved to be useful for interpreting the pH 9. The results demonstrated that a mechanistic understanding of the different removal processes at different pH conditions is important to interpret the column experimental results. At pH 5, where the precipitation of arsenic sulfide plays the major role in the removal of arsenic, the column shows a greater removal efficiency than the batch system due to the continuous dissolution of sulfide and precipitation of arsenic sulfide. At pH 9, where adsorption mainly governs the arsenic removal, the sorption nonlinearity should be considered in the estimation of the column capacity. This study highlighted the importance of understanding reaction mechanism to predict column performance using batch-obtained experimental results.

• Journal of Soil and Groundwater Environment
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• v.18 no.3
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• pp.109-118
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• 2013

Characteristics of the transport of zero-valent iron nanoparticles (nZVI) in an aquifer were investigated to evaluate an application of nZVI-based reactive zone technology. Main flow direction of groundwater was north. Preferential flow paths of the groundwater identified by natural gradient tracer test were shown northeast and northwest. The highest groundwater velocity was $4.86{\times}10^{-5}$ m/s toward northwest. When the breakthrough curves obtained from the gravity injection of nZVI were compared with the tracer curves, the transport of nZVI was retarded and retardation factors were 1.17 and 1.34 at monitoring wells located on the northeast and northwest, respectively. The ratios of the amount of nZVI delivered to the amount of tracer delivered at the two wells mentioned above were 24 and 28 times greater than that of the well on the main flow direction, respectively. Attachment efficiency based on a filtration theory was $4.08{\times}10^{-2}$ along the northwest direction that was the main migration route of nZVI. Our results, compared to attachment efficiencies obtained in other studies, demonstrate that the mobility of nZVI was higher than that of results reported in previous studies, regardless of large iron particle sizes of the current study. Based on distribution of nZVI estimated by the attachment efficiency, it was found that nZVI present within 1.05 m from injection well could remove 99% of TCE within 6 months.