• Journal of Science and Technology Studies
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• v.18 no.1
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• pp.129-175
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• 2018

This paper examines asbestos activism in South Korea by focusing on the politics of knowledge between the asbestos activist group and regulatory agency on the risk of asbestos exposure. Asbestos activism has contributed to establishing asbestos pollution an important safety and public health agenda in South Korea. Asbestos pollution investigation is key to core argument of the activism that asbestos pollution is pervasive especially in urban environment and a serious environmental health problem with its worst consequences has not yet seen. A distinctive characteristic of such asbestos investigation is the use of "settled dust analysis," non-standard, non-legislated analysis method. In this paper, literary technologies used in asbestos investigation report written by activists and controversies over asbestos pollution measurement in Samsung's head office building. Asbestos activists successfully concentrated media's attention on their argument and mobilize resources needed to make policy decisions, by using settled dust analysis data. Regulatory agency and expert group, however, neither saw settled dust analysis nor activists argument persuasive enough to make policy changes, base on their evaluation on the use of standards and evidentiary context for analyzing measured data. While its explanatory power is partially acquired, through the dispute between asbestos activists and regulatory agencies unspoken assumptions of regulatory science was revealed and became the matter of social debate. Settled dust analysis captures the characteristic of asbestos analysis which combined social movement and science to challenge the regulatory agency and expert group.

• Journal of the Korea Concrete Institute
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• v.24 no.5
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• pp.543-551
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• 2012

Road pavements in Korea generally show shorter service life than the predicted one. There are many reasons for this phenomenon including increased traffic load and other attacks from exposure conditions. In order to extend a service life and upgrade the pavement, a new multi-functional composite pavement system is being developed in Korea. This study is to investigate the performances of fiber-reinforced lean concrete for pavement base. This study considered mineral admixtures of fly ash and reject ash. The reject ash is defined as ash that does not meet the specifications for fly ash so that it cannot be used as a supplemental material for cement replacement. Due to the inherent property of lean concrete, compaction during the fabrication of specimens is a key factor. Therefore, this study suggests an appropriate compaction method. From the test results, the compressive strengths of the concrete satisfied the required limit of 5 MPa at 7 days. When a compaction roller was used to mimic actual field conditions, the strength development seemed to be influenced by the compaction energy rather than hydration of cement itself.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.93-93
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• 2009

In order to overcome the lack of reactivity with hydrogen gas ($H_2$) and utilize unique properties of Carbon Nano Tubes (CNTs) for the application to hydrogen sensors, there have been intensive works on the surface functionalization of CNTs with various types of nanoparticles including Pd. In the present work, we have investigated the effect of dendrimers and Pd nanoparticles to the hydrogen sensing properties of CNTs by comparing three types of samples: Pd/SWNTs (Sample I), Pd/dendrimer/SWNTs (Sample II) and heat-treated Pd/dendrimers/SWNTs (Sample III). As a result of IV measurement under the $H_2$ and air, sample I was found to have a high sensitivity (25%) to $H_2$, but to have a very slow response time (324 s) and recovery rate. On the other hand, Sample II was found to show much faster response time (3 s) and good recovery rate but lower sensitivity (8.6%) than Sample I which is due to induced dipole moments in the dendrimers. Interestingly, Sample III showed both fast response time (7 s) and high sensitivity (25%), indicating that the pyrolysis of the dendrimers during heat treatment which reduce the distance between the surface of the SWNTs and the functionalized Pd nanoparticles plays a key role in improving the sensitivity. The pyrolysis of the dendrimers in Pd nanoparticle-dendrimer-SWNTs was found to enable a significant electrical conductance modulation upon exposure to extremely low concentrations (10 ppm) of $H_2$ in air. Our results demonstrate that the Pd Nanoparticle-Grafted Single-Walled Carbon Nanotubes(SWNTs) with Dendrimers can be used to detect hydrogen, makingoutstanding properties such as fast response, and recovery time, high sensitivity, low detection limit at room temperature compared with other types of hydrogen sensors.

• KSBB Journal
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• v.27 no.5
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• pp.308-312
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• 2012

Argon-plasma jet (Ar-PJ) is generated by ionizing Ar gas, and the resulting Ar-PJ consists of a mixture of neutral particles, positive ions, negative electrons, and various reactive species. Although Ar-PJ has been used in various biomedical applications, little is known about the biological effects on cells located near the plasma-exposed region. Here, we investigated the effects of the Ar-PJ on actin cytoskeleton of mouse embryonic fibroblasts (MEFs) in response to indirect as well as direct exposure to Ar-PJ. This Ar-PJ was generated at 500 mL/min of flow rate and 100 V electric power by our device mainly consisting of electrodes, dielectrics, and a high-voltage power supply. Because actin cytoskeleton is the key cellular machinery involved in cellular movement and is implicated in regulation of cancer metastasis and thus resulting in a highly desirable cancer therapeutic target, we examined the actin filament architectures in Ar-PJ-treated MEFs by staining with an actin-specific phalloidin labeled with fluorescent dye. Interestingly, the Ar-PJ treatment causes destabilization of actin filament architectures in the regions indirectly exposed to Ar-PJ, but no differences in MEFs treated with Ar gas alone and in untreated cell control, indicating that this phenomenon is a specific cellular response against Ar-PJ in the live cells, which are indirectly exposed to Ar-PJ. Collectively, our study raises the possibility that Ar-PJ may have potential as anti-cancer drug effect through direct destabilization of the actin cytoskeleton.

• The Journal of Korean Physical Therapy
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• v.20 no.1
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• pp.57-65
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• 2008

Purpose: Heat shock proteins (HSPs) are a group of proteins that are activated when cells are exposed to a variety of environmental stresses, such as infection, inflammation, exposure to toxins, starvation, hypoxia, brain injury, or water deprivation. The activation of HSPs by environmental stress plays a key role in signal transduction, including cytoprotection, molecular chaperone, anti-apoptotic effect, and anti-aging effects. However, the precise mechanism for the action of small HSPs, such as HSP27 and mitogen-activated protein kinases (MAPKs: extracellular-regulated protein kinase 1/2 (ERK1/2), p38MAPK, stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK), is not completely understood, particularly in application of cell stimulators including platelet-derived growth factor (PDGF), angiotensin II (AngII), tumor necrosis factor $\alpha$ (TNF$\alpha$), and $H_2O_2$. This study examined the relationship between stimulators-induced enzymatic activity of HSP27 and MAPKs from rat smooth and skeletal muscles. Methods: 2-dimensional electrophoresis (2DE) and matrix assisted laser desorption ionizationtime-of-flight/time-of-flight (MALDI-TOF/TOF) analysis were used to identify HSP27 from the intact vascular smooth and skeletal muscles. Three isoforms of HSP27 were detected on silver-stained gels of the whole protein extracts from the rat aortic smooth and skeletal muscle strips. Results: The expression of PDGF, AngII, TNF$\alpha$, and $H_2O_2$-induced activation of HSP27, p38MAPK, ERK1/2, and SAPK/JNK was higher in the smooth muscle cells than the control. SB203580 (30${\mu}$M), a p38MAPK inhibitor, increased the level of HSP27 phosphorylation induced by stimulators in smooth muscle cells. Furthermore, the age-related and starvation-induced activation of HSP27 was higher in skeletal muscle cells (L6 myoblast cell lines) and muscle strips than the control. Conclusion: These results suggest, in part, that the activity of HSP27 and MAPKs affect stressors, such as PDGF, AngII, TNF$\alpha$, $H_2O_2$, and starvation in rat smooth and skeletal muscles. However, more systemic research will be needed into physical therapy, including thermotherapy, electrotherapy, radiotherapy and others.

• Toxicological Research
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• v.29 no.1
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• pp.43-52
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• 2013

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium that are found in cereals and agricultural products. ZEN has been implicated in mycotoxicosis in farm animals and in humans. The toxic effects of ZEN are well known, but the ability of an alkaline Comet assay to assess ZEN-induced oxidative DNA damage in Chang liver cells has not been established. The first aim of this study was to evaluate the Comet assay for the determination of cytotoxicity and extent of DNA damage induced by ZEN toxin, and the second aim was to investigate the ability of N-acetylcysteine amide (NACA) to protect cells from ZEN-induced toxicity. In the Comet assay, DNA damage was assessed by quantifying the tail extent moment (TEM; arbitrary unit) and tail length (TL; arbitrary unit), which are used as indicators of DNA strand breaks in SCGE. The cytotoxic effects of ZEN in Chang liver cells were mediated by inhibition of cell proliferation and induction of oxidative DNA damage. Increasing the concentration of ZEN increased the extent of DNA damage. The extent of DNA migration, and percentage of cells with tails were significantly increased in a concentration-dependent manner following treatment with ZEN toxin (p < 0.05). Treatment with a low concentration of ZEN toxin (25 ${\mu}M$) induced a relatively low level of DNA damage, compared to treatment of cells with a high concentration of ZEN toxin (250 ${\mu}M$). Oxidative DNA damage appeared to be a key determinant of ZEN-induced toxicity in Chang liver cells. Significant reductions in cytolethality and oxidative DNA damage were observed when cells were pretreated with NACA prior to exposure to any concentration of ZEN. Our data suggest that ZEN induces DNA damage in Chang liver cells, and that the antioxidant activity of NACA may contribute to the reduction of ZEN-induced DNA damage and cytotoxicity via elimination of oxidative stress.

• Journal of Embryo Transfer
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• v.27 no.1
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• pp.57-62
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• 2012

Efficient oocyte activation is a key step for the success of nuclear transfer in cloning. Ionomycin sequentially combined with 6-DMAP is now widely used to activate normal oocytes for analytical studies of oocyte activation and to activate reconstructed oocytes after nuclear transfer. The present study investigated sources of oocytes, duration of ionomycin and 6-DMAP, laser and electric stimulation in goat oocyte activation in order to optimize the protocols. Goat ovaries were collected in individual abattoirs during the breeding season and were delivered to the laboratory within 6 h in saline with 100 IU/ml streptomycin and 0.05 mg/ml penicillin. The oocytes were denuded from the cumulus cell by pipetting with 0.2% hyaluronidase in PBS at 20~22 hr post maturation. Oocytes with the polar body were selected and assigned to four groups for parthenogenetic activation. To examine the effect of duration of ionomycin treatment, oocytes after 20~22 hr of maturation were treated with 2.5 uM ionomycin for 1 or 5 min times and then cultured in 2 mM 6-DMAP for 2 or 4 hr. The activated oocytes were cultured in mSOF at $38.5^{\circ}C$ in $CO_2$ 5%, $O_2$ 5% and $N_2$ 90% multi incubator. Cleavage and blastocyst development was observed at 48 hr and day 8 of culture $in$ $vitro$, respectively. Activation rates of oocytes exposed to ionomycin for 1 min(86.4%) were significantly higher than those treated for 5 min(74.3%) duration. This indicated that 1 min ionomycin treatment was most suitable for activation of goat oocytes. The duration of 6-DMAP treat duration was in 2 mM 6-DMAP for 2 hr after 1 min exposure to 2.5 uM ionomycin. The activation rate of oocytes incubated in 6-DMAP for 2 hour(82.5%) was significantly higher than those in oocytes treated with 4 hr(75.5%).

• Korean journal of communication and information
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• v.73
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• pp.7-34
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• 2015

This study attends to the effects of political entertainment as a newly emerging television genre on citizens' political talk. Particularly, this study suggests audience involvement and political information efficacy as key psychological factors that mediate the relationship between political entertainment and political discussion. More specifically, audience involvement was deemed as a conclusive concept that consists of such sub-dimensions as audience identification and parasocial interaction with program characters and transportation into the messages. Among 317 participants in an online survey, a total of 273 subjects, who had at least some viewing experience with political entertainment TV programs, were included in the final analysis. According to the findings, softer programs that piggyback political information on top of their entertainment content were more likely to increase viewers' identification and transportation. The viewer experience of identification further heightened the level of political information efficacy, which in turn positively contributed to one's willingness to participate in political talk and to hear the other side. It also appeared that political information efficacy significantly mediated the relationship between political entertainment viewing and political talk.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.3 s.52
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• pp.245-251
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• 2005

Safety is one of the key issue in the regulation of cosmetics. Cosmetic Act deals with it in Korea. The guidance for the testing cosmetic ingredients and their safety evaluation are prepared by Korea Food and Drug Administration. Ultraviolet radiation could Induce skin damage, edema, erythema, photoaging, immune dysfunction and skin cancer. Ultraviolet radiation is classified as Group 2A(probably carcinogenic to humans) by International Agenry for Reaserch on Cancer(IARC). The in vitro methodologies for evaluating the toxic potential of ingredients reported in the literature have not yet been sufficiently validated for use in areas other than the study for mutagenicity/genotoxicity, for pre-screening for severe irritancy, for screening of phototoxicity and for evaluating the percutaneous absorption. The 3T3 neutral red uptake photoxicity test (3T3 NRU PT) was accepted as OECD toxicity guideline in 2002. The 3T3 NRU PT is an in vitro method based on a comparison of the cytotoxicitv of a chemical when tested in the presence and in the absence of exposure to a non-cytotoxic dose of UVA/visible light.

• Journal of Life Science
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• v.22 no.10
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• pp.1399-1406
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• 2012

The present study was conducted to evaluate the effects of various extracts of Hizikia fusiforme on the anti-obesity effects in 3T3-L1 preadipocytes. We used H. fusiforme extracts from ethanol (EEHF), dichloromethane (CFHF), ethyl acetate (EAFHF), butanol (BFHF), and water (WFHF). Treatment with these extracts significantly suppressed terminal differentiation of 3T3-L1 preadipocytes in a dose-dependent manner as confirmed by a decrease in lipid droplet content through Oil Red O staining; this effect was higher in WFHF than in other extracts. The concentrations of cellular triglyceride were also reduced in 3T3-L1 cells by exposure with these extracts, especially when compared with the controls. Treatment with 200 ${\mu}g/ml$ of WFHF and CFHF caused approximately 42.6% and 23.7% reduction, respectively. In addition, the extracts of H. fusiforme significantly reduced the expression levels of key pro-adipogenic transcription factors, including peroxisome proliferator-activated receptor ${\gamma}$ ($PPAR{\gamma}$) and CCAAT/enhancer binding proteins ${\alpha}$ (C/$EBP{\alpha}$) and C/$EBP{\beta}$ as compared with controls. Accordingly, our data indicated that WFHF has a preeminent effect on inhibition of adipocyte differentiation among various extracts, and H. fusiforme extracts may be an ideal candidate for obesity relief.