• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2533-2538
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• 2014

In this study, 2-zone model CFAST software was used to predict the fire hazard of karaoke. Model is a three-dimensional unsteady state. Accuracy of CFAST is verified by comparing result of CFAST analysis with result of real fire experiment. For analysis results, the oxygen concentration were reduced to 10% within 5 minutes in room 5, the carbon dioxide concentration were increased to 5%. Therefore, at the enclosed space like karaoke, we can predict that dangerous situation would occur and people be suffocated because of toxic gas.

• The KIPS Transactions:PartB
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• v.11B no.3
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• pp.281-288
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• 2004

In order to extract and analyze complex features of the behavior of animals in response to external stimuli such as toxic chemicals, we implemented an adaptive computational method to characterize changes in the behavior of chironomids in response to treatment with the insecticide, diazinon. In this paper, we propose an energy minimization model to extract the features of response behavior of chironomids under toxic treatment, which is applied on the image of velocity vectors. It is based on the improved active contour model and the variations of the energy functional, which are produced by the evolving active contour. The movement tracks of individual chironomid larvae were continuously measured in 0.25 second intervals during the survey period of 4 days before and after the treatment. Velocity on each sample track at 0.25 second intervals was collected in 15-20 minute periods and was subsequently checked to effectively reveal behavioral states of the specimens tested. Active contour was formed around each collection of velocities to gradually evolve to find the optimal boundaries of velocity collections through processes of energy minimization. The active contour which is improved by T. Chan and L. Vese is used in this paper. The energy minimization model effectively revealed characteristic patterns of behavior for the treatment versus no treatment, and identified changes in behavioral states .is the time progressed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.171-176
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• 2000

Bioremediation of hazardous hydrophobic organic compounds, such as polycyclic aromatic hydrocarbons (PAHs), is a major environmental concern due to their toxic and carcinogenic properties. Due to their hydrophobicity, the hydrophobic organic compounds are mainly associated with the soil organic matter or nonaqueous-phase liquids. A major question concerns the relationships between biodegradation and sorption. This work develops and utilizes a non- steady state model for evaluating the interactions between sorption and biodegradation of phenanthrene, a 3-ring PAH compound, in soil-slurry systems. The model includes sorption/desorption of a target compound, its utilization by microorganisms as a primary substrate existing in the dissolved phase and/or the sorbed phase in biomass and soil, oxygen transfer, and oxygen utilization as an electron acceptor. Biodegradation tests with phenanthrene were conducted in liquid and soil-slurry systems. The soil-slurry tests were performed with very different mass transfer rate: fast mass transfer in a flask test at 150 rpm, and slow mass transfer in a roller-bottle test at 2 rpm. In the slurry tests, phenanthrene was degraded more rapidly than in liquid tests, but with a similar rate in both slurry systems. Modeling analyses with several hypotheses indicate that a model without biodegradation of compound sorbed to the soil was not able to account for the rapid degradation of phenanthrene, particularly in the roller bottle slurry test. Reduced mass-transfer resistance to bacteria attached to the soil is the most likely phenomenon accounting for rapid sorbed-phase biodegradation.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.4
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• pp.503-510
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• 2011

Ammonia in water which is toxic to human, its concentration is regulated below 0.5 mg/L in drinking water. Current study aimed to develop appropriate models for ammonia stripping using hollow fiber membrane contactor. Two different models were developed during the study. Model 1 was assumed only free ammonia ($NH_3$) transfer in stripping process, whereas the Model 2 was assumed with total ammonia ($NH_3+{NH_4}^+$) transfer. Ammonium chloride ($NH_4CI$), sodium hydroxide(NaOH) were used to make ammonia solution, which was concentration of 25 mg as N/L at a pH of 10.5. The experimental conditions were such that, the liquid flow was in tube-side in upward direction and t he gas flow was on shell-side in downward direction a t room temperature. The experimental and modeling results showed that marginal difference were observed at low gas flux. However the difference between the both models and experimental value were increased when the gas flux was increased. The study concludes that the Model 1 with free ammonia is more appropriate when both models were compared and useful in ammonia stripping process at low gas flux.

• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.3030-3034
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• 2014

Bis-chloroethylnitrosourea (BCNU) is currently used as an anti-cancer drug for glioblastoma therapy. In this study, BCNU was loaded into the hydrophobic cores of R3V6 amphiphilic peptide micelles for efficient delivery into brain tumors. The scanning electron microscope (SEM) study showed that the BCNU-loaded R3V6 peptide micelles (R3V6-BCNU) formed spherical micelles. MTT assay showed that R3V6-BCNU more efficiently induced cell death in C6 glioblastoma cells than did BCNU. In the Annexin V assay, R3V6-BCNU more efficiently induced apoptosis than did BCNU alone. Furthermore, the results showed that R3V6 was not toxic to cells. The positive charges of the R3V6 peptide micelles may facilitate the interaction between R3V6-BCNU and the cellular membrane, resulting in an increase in cellular uptake of BCNU. In vivo evaluation with an intracranial glioblastoma rat model showed that R3V6-BCNU more effectively reduced tumor size than BCNU alone. The results suggest that R3V6 peptide micelles may be an efficient carrier of BCNU for glioblastoma therapy.

• Journal of Environmental Health Sciences
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• v.43 no.5
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• pp.412-421
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• 2017

Objectives: To establish a system for integrated risk assessment of EDCs in Korea, infrastructure for providing toxicity data of ecological media should be established. Some systems provide soil ecotoxicity databases along with aquatic ecotoxicity information, but a well-structured ecotoxicity database system is still lacking. Methods: Aquatic and soil ecotoxicological information were collected by a toxicologist based on a human readable data (HRD) format for collecting ecotoxicity data that we provided. Among these data, anomalies were removed according to database normalization theory. Also, the data were cleaned and encoded to establish a machine-readable data (MRD) ecotoxicity database system. Results: We have developed a multi-purpose ecotoxicity database model focusing on EDCs, ecological species, and toxic effects. Also, we have constructed a web-based data searching system to retrieve, extract, and download data with greater availability. Conclusions: The results of our study will contribute to decision-making as a tool for efficient ecological risk assessment of EDCs in Korea.

• Journal of Korea Water Resources Association
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• v.49 no.9
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• pp.789-798
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• 2016

Frequent algal blooms at major river systems in Korea have been serious social and environmental problems. Especially, the appearance of cyanobacteria with toxic materials is a threat to secure a safe drinking water. In order to model the behaviour of cyanobacteria cell number, an exclusive causality analysis using prewhitening technique was introduced to delineate effective parameters to predict the cell numbers of cyanobacteria in Seungchon Weir and Juksan Weir along Youngsan river system. Both input and output transfer function models were obtained to explain temporal variation of cyanobacteria cell number. A threshold behaviour of water temperature was implemented into the model development to consider winter characteristic of cyanobacteria. The implementation of water temperature threshold into the model structure improves the predictability in simulation. Even though the input output transfer model cannot completely explained all blooms of cyanobacteria, the simple structure of model provide a feasibility in application which can be important in practical aspect.

• Clinical and Experimental Reproductive Medicine
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• v.31 no.1
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• pp.59-65
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• 2004

Objectives: The aim of this study was to assess toxicities of cryoprotectants. Methods: Toxicities of two cryoprotectants, dimethyl sulfoxide (DMSO) and 1, 2-propanediol (PROH), were investigated using a murine embryo model. Female F-1 mice were stimulated with gonadotropin, induced ovulation with hCG and mated. Two cell embryos were collected and cultured after exposure to either DMSO or PROH. Embryo development was evaluated up to the blastocyst stage. Blastocysts were stained with bis-benzimide to evaluate the cell count and with terminal deoxynucleotidyl transferase mediated dUTP nick labeling (TUNEL) to assess apoptosis. Results: The total cell count of blastocysts that were treated with DMSO at the 2-cell stage was significantly lower than that were treated with PROH ($75.9{\pm}27.0$) or the control ($99.0{\pm}18.3$) (p<0.001). On comparison of two cryoprotectant treated groups, the DMSO treated group showed a decreased cell count compared with the PROH treated group (p<0.05). Both DMSO ($14.2{\pm}1.5$) and PROH ($11.2{\pm}1.4$) treated groups showed higher apoptosis rates of cells in the blastocyst compared with the control ($6.2{\pm}0.9$, p<0.0001). In addition, the DMSO treated group showed more apoptotic cells than the PROH treated group (p<0.001). Conclusions: The potential toxicity of cryoprotectants was uncovered by prolonged exposure of murine embryos to either DMSO or PROH at room temperature. When comparing two cryoprotective agents, PROH appeared to be less toxic than DMSO at least in a murine embryo model.

• Journal of Pharmacopuncture
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• v.19 no.4
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• pp.319-328
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• 2016

Objectives: Advancements in nanotechnology have led to nanoparticle (NP) use in various fields of medicine. Although the potential of NPs is promising, the lack of documented evidence on the toxicological effects of NPs is concerning. A few studies have documented that homeopathy uses NPs. Unfortunately, very few sound scientific studies have explored the toxic effects of homeopathic drugs. Citing this lack of high-quality scientific evidence, regulatory agencies have been reluctant to endorse homeopathic treatment as an alternative or adjunct treatment. This study aimed to enhance our insight into the impact of commercially-available homeopathic drugs, to study the presence of NPs in those drugs and any deleterious effects they might have, and to determine the distribution pattern of NPs in zebrafish embryos (Danio rerio). Methods: Homeopathic dilutions were studied using high-resolution transmission electron microscopy with selected area electron diffraction (SAED). For the toxicity assessment on Zebrafish, embryos were exposed to a test solution from 4 - 6 hours post-fertilization, and embryos/larvae were assessed up to 5 days post-fertilization (dpf ) for viability and morphology. Toxicity was recorded in terms of mortality, hatching delay, phenotypic defects and metal accumulation. Around 5 dpf was found to be the optimum developmental stage for evaluation. Results: The present study aimed to conclusively prove the presence of NPs in all high dilutions of homeopathic drugs. Embryonic zebrafish were exposed to three homeopathic drugs with two potencies (30CH, 200CH) during early embryogenesis. The resulting morphological and cellular responses were observed. Exposure to these potencies produced no visibly significant malformations, pericardial edema, and mortality and no necrotic and apoptotic cellular death. Conclusion: Our findings clearly demonstrate that no toxic effects were observed for these three homeopathic drugs at the potencies and exposure times used in this study. The embryonic zebrafish model is recommended as a well-established method for rapidly assessing the toxicity of homeopathic drugs.

• Toxicological Research
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• v.14 no.2
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• pp.183-191
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• 1998

It has been reported that 50~70% of child asthma, bronchial asthma in adult, and allergic rhinitis are caused by house dust mite. The antigen extracted from house dust mite has been used for effective treatment against allergic diseases and for clinical test. This house dust mite antigen has been entirely imported from abroad. However, the composition and content of all the antigen imported vary from a brand to other brand. Thus, we need to standardize the composition and content of the antigen by developing it domestically. We proceeded pre-clinically general pharmacological test and toxicological test that are required for the eventual human use by utilizing the house dust mite cultured in Korea. In order to obtain information on general pharmacological tests such as its toxic signs in tissues or organs which are mainly affected, we examined the effect of house dust mite on the tensions of the isolated tissues and heart rates of cardiac muscle by recording with force displacement transducer of polygragh (Glass Model 7). We determined lethality of antigen extracted from house dust mite in mice and guinea pigs. We examined acute and subacute toxicity by administrating house dust mite extract of 500, 100, 20 times of the expected clinical dose. In male and female mice and guinea pigs, given a sigle intraperitoneal dose of antigen, $LD_{50}$ values were over 5.0 $\textrm{m}{\ell}$/kg, respectively. In animals administrated with house dust mite, there were no significant change of clinical symptom, body weight, food consumption, water consumption, eye examinations, urinalysis, blood biochemistry, and histopathological examinations in any animals tested. We found no toxic effect of this house dust mite. These results show that the house dust mite cultured by us could be used in the development of medicine against allergic diseases caused by the antigen of house dust mite.