• Journal of Korean Society on Water Environment
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• v.18 no.2
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• pp.189-199
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• 2002

Nitrogen, in its various forms, can deplete dissolved oxygen levels in receiving waters, stimulate aquatic growth, exhibit toxicity toward aquatic life and affect the suitability of sewage for reuse. Pilot-scale Rotating Biological Contactor(RBC) experiments were conducted to examine biological nitrification, respectively, of municipal sewage with five different internal recirculation ratios of 0, 1, 2, 3, and 4 using the constant hydraulic loading of $205L/m^2{\cdot}day$. The use of internal recirculation improved nitrification on account of the dilution of biodegradable organic carbon in influent sewage down to 15 mg/L of $SBOD_5$ or less. Ammonium nitrogen of $14.3{\pm}2.4%$ was consumed by cellular assimilation without the occurrence of denitrification. The thickness of biofilm didn't seem effect significantly the nitrification and denitrification. Nitrification with internal recirculation was found to occur using hydraulic loading rate of as high as $205L/m^2{\cdot}day$, which was beyond the generally known values of it.

• Korean Journal of Pharmacognosy
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• v.29 no.1
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• pp.1-7
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• 1998

Aqueous extract of Morus alba L. blocked the toxic effect of paraquat on E. coli growth. The active components in the extract may be capable of crossing the cell membranes and protect against superoxide toxicity in E. coli, The extract inhibited $FeSO_4/H_2O_2$ induced lipid peroxidation in rat liver homogenate and protected against t-butyl hydroperoxide caused Ac2F cell damage. Moreover, the extract showed inhibitory effect on phospholipase $A_2$ activity in a dose dependent manner. Antiinflammatory effect of the extract was further investigated using the carrageenin-induced oedema model. A single adminstration of the extract (3g/kg body, p.o.) was more effective than indomethacin. These results suggest that the isolation and identification of the active components would have significant therapeutic application to inflammation associated with oxygen radicals.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.397-400
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• 2008

Traditional propellants which have a hypergolic characteristic have a high performance but also have disadvantages of toxicity and complex handling requirement. In order to replace these propellants, one of the alternatives is hydrogen peroxide which generates high temperature oxygen and water vapor after catalytic reaction. In this paper, autoignition characteristics of kerosene by decomposed hydrogen peroxide were investigated to perform fundamental research for designing a thruster using hydrogen peroxide and kerosene propellants. Contraction ratio, whether flame holder exists or not, and feeding pressure of propellants were selected as variables. From the experiments for different mixture ratio, we confirmed the ignition stability is strongly affected by a feeding pressure of propellants.

• Archives of Plastic Surgery
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• v.46 no.3
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• pp.189-197
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• 2019

There has been an exponential increase in plastic surgery cases over the last 20 years, surging from 2.8 million to 17.5 million cases per year. Seventy-two percent of these cases are being performed in the office-based or ambulatory setting. There are certain advantages to performing aesthetic procedures in the office, but several widely publicized fatalities and malpractice claims has put the spotlight on patient safety and the lack of uniform regulation of office-based practices. While 33 states currently have legislation for office-based surgery and anesthesia, 17 states have no mandate to report patient deaths or adverse outcomes. The literature on office-base surgery and anesthesia has demonstrated significant improvements in patient safety over the last 20 years. In the following review of the proceedings from the PRS Korea 2018 meeting, we discuss several key concepts regarding safe anesthesia for office-based cosmetic surgery. These include the safe delivery of oxygen, appropriate local anesthetic usage and the avoidance of local anesthetic toxicity, the implementation of Enhanced Recovery after Surgery protocols, multimodal analgesic techniques with less reliance on narcotic pain medications, the use of surgical safety checklists, and incorporating "the patient" into the surgical decision-making process through decision aids.

• Korean Journal of Pharmacognosy
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• v.52 no.3
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• pp.149-156
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• 2021

Excessive glutamate can cause oxidative stress in neuronal cells and this can be the reason for neurodegenerative disease. In this study, we investigated the protective effect of Spirulina maxima hot ethanol extract on mouse hippocampal HT22 cell of which glutamate receptor has no function. HT22 cells were pre-treated with S. maxima sample at a dose dependent manner (1, 10 and 100 ㎍/ml). After an hour, glutamate was treated. Cell viability, reactive oxygen species (ROS) accumulation, Ca²⁺ influx, decrease of mitochondrial membrane potential level and glutathione related assays were followed by then. S. maxima ethanol extract improved the cell viability by suppressing the ROS and Ca²⁺ formation, retaining the mitochondrial membrane potential level and protecting the activity of the antioxidant enzymes compared with group of vehicle-treated controls. These suggest that S. maxima may decelerate the neurodegeneration by attenuating neuronal damage and oxidative stress.

• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.167-173
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• 2021

Reactive oxygen species (ROS) disrupt the cellular redox balance, exert cytotoxic effects, and consequently promote the development of various diseases in humans. Previous studies have reported that antioxidants counteract the adverse effects of ROS. Several studies examine the whitening effects of various agents based on their ability to inhibit tyrosinase activity. Tyrosinase is a critical enzyme involved in the synthesis of melanin, which protects the skin against radiation. Various agents exhibiting antioxidant and tyrosinase inhibitory activities have been synthesized. However, these synthetic drugs are associated with toxicity, decreased safety, and poor skin penetration in vivo, which has limited the clinical application of synthetic drugs. This study examined the antioxidant and tyrosinase inhibitory activities of some microalgae. The methanol, dichloromethane, and ethyl acetate extracts of four microalgal species (Tetraselmis tetrathele, Dunaliella tertiolecta, Platymonas sp., and Chaetoceros simplex) were prepared. The physiological and whitening effects of microalgal extracts were investigated by measuring the antioxidant and tyrosinase inhibitory activities. The ethyl acetate extract of D. tertiolecta exhibited the highest antioxidant and tyrosinase inhibitory activities. Future studies must focus on examining the whitening effects of microalgae on cell lines to facilitate the development of microalga-based therapeutics for skin diseases, functional health foods, and whitening agents. Thus, microalgae have potential applications in the pharmaceutical, food, and cosmetic industries.

• Journal of Marine Bioscience and Biotechnology
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• v.14 no.1
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• pp.33-42
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• 2022

Tacrolimus, a type of macrolide produced by Streptomyces tsukubaensis, is widely used as an immunosuppressant. However, continuous exposure to tacrolimus causes oxidative stress in normal cells, ultimately inducing cell injury. Therefore, this study investigated whether luthione, a reduced glutathione, could inhibit tacrolimus-induced cytotoxicity in olive flounder (hirame) natural embryo (HINAE) cells. According to the results, luthione significantly inhibited tacrolimus-induced reduction in cell viability in a concentration-dependent manner. Additinally, although luthione unaffected autophagy by tacrolimus, tacrolimus-induced apoptosis was significantly suppressed in the presence of luthione. Luthione also markedly blocked DNA damage in tacrolimus-treated HINAE cells, associated with the inhibition of reactive oxygen species (ROS) generation. Additionally, tacrolimus cytotoxicity in HINAE cells was correlated with increased inflammatory response, also attenuated by luthione. Collectively, these results show that at least luthione protects HINAE cells against tacrolimus-induced DNA damage, apoptosis, and inflammation, but not autophagy, by scavenging ROS. Although additional in-vivo studies are required, this study's results can be used as a basis for utilizing luthione to reduce the toxicity of fish cells caused by excessive immune responses.

• Archives of Pharmacal Research
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• v.23 no.4
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• pp.267-282
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• 2000

Cytochrome P45O (CYP) 2E1 catalyzes the metabolism of a wide variety of therapeutic agents, procarcinogens, and low molecular weight solvents. CYP2E1-catalyzed metabolism may cause toxicity or DNA damage through the production of toxic metabolites, oxygen radicals, and lipid peroxidation. CYP2E1 also plays a role in the metabolism of endogenous compounds including fatty acids and ketone bodies. The regulation of CYP2E1 expression is complex, and involves transcriptional, post-transcriptional, translational, and post-translational mechanisms. CYP2E1 is transcriptionally activated in the first few hours after birth. Xenobiotic inducers elevate CYP2E1 protein levels through both increased translational efficiency and stabilization of the protein from degradation, which appears to occur primarily through ubiquitination and proteasomal degradation. CYP2E1 mRNA and protein levels are altered in response to pathophysiologic conditions by hormones including insulin, glucagon, growth hormone, and leptin, and growth factors including epidermal growth factor and hepatocyte growth factor, providing evidence that CYP2E1 expression is under tight homeostatic control.

• BMB Reports
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• v.56 no.11
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• pp.575-583
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• 2023

Mitochondria, fundamental cellular organelles that govern energy metabolism, hold a pivotal role in cellular vitality. While consuming dioxygen to produce adenosine triphosphate (ATP), the electron transfer process within mitochondria can engender the formation of reactive oxygen species that exert dual roles in endothelial homeostatic signaling and oxidative stress. In the context of the intricate electron transfer process, several metal ions that include copper, iron, zinc, and manganese serve as crucial cofactors in mitochondrial metalloenzymes to mediate the synthesis of ATP and antioxidant defense. In this mini review, we provide a comprehensive understanding of the coordination chemistry of mitochondrial cuproenzymes. In detail, cytochrome c oxidase (CcO) reduces dioxygen to water coupled with proton pumping to generate an electrochemical gradient, while superoxide dismutase 1 (SOD1) functions in detoxifying superoxide into hydrogen peroxide. With an emphasis on the catalytic reactions of the copper metalloenzymes and insights into their ligand environment, we also outline the metalation process of these enzymes throughout the copper trafficking system. The impairment of copper homeostasis can trigger mitochondrial dysfunction, and potentially lead to the development of copper-related disorders. We describe the current knowledge regarding copper-mediated toxicity mechanisms, thereby shedding light on prospective therapeutic strategies for pathologies intertwined with copper dyshomeostasis.

• Journal of Plant Biotechnology
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• v.50
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• pp.76-81
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• 2023

As cultured plant cells can grow in high oxidative stress conditions, they form an excellent system to study antioxidant mechanisms and the mass production of antioxidants. Oxidative stress is a major cause of damage in plants exposed to various types of environmental stress, including heavy metals, such as cadmium (Cd). Heavy metal accumulation can interfere with many cell functions and plant growth. To evaluate the contribution of oxidative stress to Cd-induced toxicity, cultured sweetpotato (Ipomoea batatas) cells were treated with increasing concentrations of Cd (0, 10, 25, and 50 μM) and cultured further. Cell growth was significantly inhibited by 25 and 50 μM of Cd, and the total protein content increased with 50 μM of Cd. Additionally, the activity of peroxidase (POD) and ascorbate peroxidase (APX), antioxidant enzymes that remove hydrogen peroxide (a reactive oxygen species), increased in the cells after treatment with 50 μM of Cd. The expression analysis of POD, APX, and peroxiredoxin (PRX) isolated from sweetpotato cultured cells in a previous study revealed the differential expression of POD in response to Cd. In this study, the expression levels of several acidic POD (swpa2, swpa3, and swpa4) and basal POD (swpb1, swpb2, and swpb3) genes were increased in Cd-treated cultured cells. These results indicate that Cd-mediated oxidative stress is closely linked to improved POD-mediated antioxidant defense capacity in sweetpotato suspension-cultured cells.