• Korean Journal of Microbiology
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• v.54 no.1
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• pp.46-52
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• 2018

Biodegradation pathway of dibenzofuran (DBF) of Novosphingobium pentaromativorans US6-1, a high-molecular-weight polycyclic aromatic hydrocarbons degrading strain, was investigated via analysis of metabolic intermediates and transcriptome. As a result, 3(2H)-benzofuranone, a basic skeleton of the metabolic intermediates produced by lateral dioxygenation process, was detected as an intermediate. RNA-Seq analysis confirmed that most of the expressed genes upon exposure to DBF were related to the lateral degradation pathway. Based on these results, the biodegradation pathway of DBF by N. pentaromativorans US6-1 was proposed.

• Journal of Environmental Impact Assessment
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• v.14 no.5
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• pp.291-303
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• 2005

Impact pathway analysis(IPA) is a bottom-up approach to estimates health and environmental risks from emissions of classical pollutants (eg. $PM_{10}$, $SO_2$, $NO_x$ and CO). The model starts from the emission rates of facility, calculates the yearly mean concentrations of pollutants at the ground level using atmospheric dispersion models. After this, proper epidemiological exposure-response functions are applied to determine the impact on the receptors. Finally the methodology can monetise the calculated physical impact on the basis of selected economic evaluation. The aim of this study is to evaluate an external cost of virtual point source in Suwon area using IPA. The results shows minor modification of local input data can make it possible to apply the model to Suwon area.

• Toxicological Research
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• v.24 no.3
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• pp.201-206
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• 2008

Exposure to formaldehyde(FA) is closely associated with adverse health effects such as irritation, inflammation, and squamous cell carcinomas of the nasal cavities. Owing to its rapid metabolism and elimination, exposure to FA does not always result in an increased concentration in blood or urine of animals and humans. Therefore, the development of biomarkers for FA exposure is necessary for risk assessment. In the present study, the effects of FA were investigated on the expression of genes involved in the MAPK pathway in vitro and results confirmed in rats exposed to FA by inhalation. Treatment of Hs 680.Tr human tracheal epithelial cells with FA induced gene expression for PDGFA, TNFSF11, SHC1, and HRAS. HRAS expression was also increased in tracheas of rats exposed to FA. In addition, FA exposure induced the expression of RASSF4, a member of the Rasassociation domain family of Ras effectors, in rat tracheas. In conclusion, data showed FA-inducible expression of genes involved in the MAPK pathway occurred and increased expression of HRAS and RASSF4 was noted in rat tracheas subchronically exposed to FA by inhalation. These genes may serve as molecular targets of FA toxicity facilitating the understanding of the toxic mechanism.

• Molecules and Cells
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• v.26 no.2
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• pp.200-205
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• 2008

The mitogen-activated protein kinase (MAPK) signaling pathway is activated in response to extracellular stimuli and regulates various activities in eukaryotic cells. Following exposure to stimuli, MAPK is known to be activated via dual phosphorylation at a conserved TxY motif in the activation loop; both threonine and tyrosine residues are phosphorylated by an upstream kinase. However, the mechanism underlying dual phosphorylation is not clearly understood. In the budding yeast Saccharomyces cerevisiae, the Hog1 MAPK mediates the high-osmolarity glycerol (HOG) signaling pathway. Tandem mass spectrometry and phosphospecific immunoblotting were performed to quantitatively monitor the dynamic changes occurring in the phosphorylation status of the TxY motif of Hog1 on exposure to osmotic stress. The results of our study suggest that the tyrosine residue is preferentially and dynamically phosphorylated following stimulation, and this in turn leads to the dual phosphorylation. The tyrosine residue was hyperphosphorylated in the absence of a threonine residue; this result suggests that the threonine residue is critical for the control of signaling noise and adaptation to osmotic stress.

• Journal of the Korean Medical Association
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• v.61 no.11
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• pp.655-661
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• 2018

Incidence of basal and squamous cell carcinoma is increasing among Korean. With increasing this incidence we need to attend the management and prevention of these cutaneous malignancies. Basal cell carcinoma (BCC) is the most common skin malignancy. Sun exposure is the most important environmental cause of BCC. Daily sun protection especially avoiding sun exposure between 10 a.m. and 4 p.m. provides most effective prevention against chronic ultraviolet-induced skin damage. Hedgehog pathway inhibitors are used locally advanced and metastatic BCC lesions in Korea. Until recently, there are no reports whether it developed resistance of Hedgehog pathway inhibitors with advanced BCC in Korean patients. Among malignant skin tumors, 19.1% were squamous cell carcinoma (SCC). The incidence of SCC was rapidly increased over the past years. However, the incidence rate of SCC in Japan has not been changed from the period 1976-1980 to 1986-1990. Sentinel lymph node biopsy for SCC did not provide diagnostic value. Bowen's disease and Erythroplasia of Queyrat are considered as carcinoma in situ of the skin. Erythroplasia of Queyrat have worse prognosis with a higher rate of malignant degeneration. Dermoscopy may helpful tool in assisting the noninvasive diagnosis of carcinoma in situ of the skin.

• The Journal of the Korean dental association
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• v.52 no.5
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• pp.281-290
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• 2014

Tooth eruption disturbance is seen commonly in mixed dentition or early permanent dentition. During this period of time, children experience the growth and development of craniofacial skeleton and dentition, so the impaction and eruption disturbance of permanent teeth make many problems in oral and maxillofacial areas. Eruption guidance of impacted tooth is not simple because many factors related to impaction are considered. Several factors such as etiology, tooth development stage, location of impacted teeth or eruption pathway, patient cooperation, etc. need to be taken into consideration in deciding the management of the impacted tooth. In the present study, it was assessed the etiology and impaction status of impacted tooth through various cases, and try to explain the treatment method to guide eruption by surgical exposure.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.1
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• pp.13-22
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• 2022

The decommissioning of a nuclear power plant generates large amounts of radioactive waste, which is of several types. Radioactive concrete powder is classified as low-level waste, which can be disposed of in a landfill. However, its safe disposal in a landfill requires that it be immobilized by solidification using cement. Herein, a safety assessment on the disposal of solidified radioactive concrete powder waste in a conceptual landfill site is performed using RESRAD. Furthermore, sensitivity analyses of certain selected input parameters are conducted to investigate their impact on exposure doses. The exposure doses are estimated, and the relative impact of each pathway on them during the disposal of this waste is assessed. The results of this study can be used to obtain information for designing a landfill site for the safe disposal of low-level radioactive waste generated from the decommissioning of a nuclear power plant.

• Toxicological Research
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• v.28 no.1
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• pp.19-24
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• 2012

In the present study, toxicity of silver nanoparticles (AgNPs) was investigated in the nematode, Caenohabditis elegans focusing on the upstream signaling pathway responsible for regulating oxidative stress, such as mitogen-activated protein kinase (MAPK) cascades. Formation of reactive oxygen species (ROS) was observed in AgNPs exposed C.elegans, suggesting oxidative stress as an important mechanism in the toxicity of AgNPs towards C. elegans. Expression of genes in MAPK signaling pathways increased by AgNPs exposure in less than 2-fold compared to the control in wildtype C.elegans, however, those were increased dramatically in sod-3 (gk235) mutant after 48 h exposure of AgNPs (i.e. 4-fold for jnk-1 and mpk-2; 6-fold for nsy-1, sek-1, and pmk-1, and 10-fold for jkk-1). These results on the expression of oxidative stress response genes suggest that sod-3 gene expression appears to be dependent on p38 MAPK activation. The high expressions of the pmk-1 gene 48 h exposure to AgNPs in the sod-3 (gk235) mutant can also be interpreted as compensatory mechanisms in the absence of important stress response genes. Overall results suggest that MAPK-based integrated stress signaling network seems to be involved in defense to AgNPs exposure in C.elegans.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.2
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• pp.131-138
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• 2009

The binding of interleukin-6 (IL-6) cytokine family ligands to the gp130 receptor complex activates the Janus kinase (JAK)/ signal transducer and activator of transcription 3 (STAT3) signal transduction pathway, where STA T3 plays an important role in cell survival and tumorigenesis. Constitutive activation of STAT3 has been frequently observed in many cancer tissues, and thus, blocking of the gp130 signaling pathway, at the JAK level, might be a useful therapeutic approach for the suppression of STAT3 activity, as anticancer therapy. AG490 is a tyrphostin tyrosine kinase inhibitor that has been extensively used for inhibiting JAK2 in vitro and in vivo. In this study, we demonstrate a novel mechanism associated with AG490 that inhibits the JAK/STAT3 pathway. AG490 induced downregulation of gp130, a common receptor for the IL-6 cytokine family compounds, but not JAK2 or STAT3, within three hours of exposure. The downregulation of gp130 was not caused by enhanced degradation of gp130 or by inhibition of mRNA transcription. It most likely occurred by translation inhibition of gp130 in association with phosphorylation of the eukaryotic initiation factor-2 a. The inhibition of protein synthesis of gp130 by AG490 led to immediate loss of mature gp130 in cell membranes, due to its short half-life, thereby resulting in reduction in the STAT3 response to IL-6. Taken together, these results suggest that AG490 blocks the STAT3 activation pathway via a novel pathway.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4B
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• pp.261-266
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• 2012

In this study, soil environmental impact assessment using risk-based approach was compared with that using concentration-based approach. For this, heavy metal contaminant exposure was characterized in an abandoned mine area. According to the estimated carcinogenic and non-carcinogenic risks, soil ingestion was identified as the most dominant exposure pathway. When contaminant concentrations exceeded the Korean Soil Contamination Warning Standards, their corresponding risk values also exceeded the Total Soil Risk Standard. Even the cases of satisfying the Korean Soil Contamination Warning Standards mostly showed higher risk levels than the Total Soil Risk Standard, re-confirming a more sensitivity of the risk-based assessment than concentration-based assessment. However, the in-depth analysis of the estimated non-carcinogenic risk values revealed a few cases for soil contact pathway showing contaminant concentrations higher than the Korean Soil Contamination Warning Standards although their non-carcinogenic risk values satisfied the level of Hazard Index Standard. The findings from this study support a necessity of shifting policy paradigm from concentration-based approach into risk-based approach for reliable risk assessment in abandoned mine areas, and also suggest a necessity of further fundamental studies regarding risk factors and standards.