• Journal of the Korean Society of Safety
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• v.8 no.3
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• pp.34-43
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• 1993

This paper presents a study on the characteristics and safety criteria for human body in ELF (Extremely Low Frequency : 50-60Hz) electric and magnetic fields. Many researches for ELF electric and magnetic fields, which are developed in the past, are studied and analyzed In this paper. In order to estabilish the safety criteria for human body in the field, the field intensity, induced current and voltage are calculated by the electrostatic field approach which is far simpler than the electromagnetic field one based on Maxwell equation. The method is applied to the 345 KV transmission line system In operation and 765 KV system under consideration. According to the results, the maximum value of field intensity, 6.8627KV/m, is evaluated at the location which is 14m away from transmission line. As the safety criteria value by the abroad researches asserting that the human can detect the Induced current in 6KV/m and above, 5KV/m and 7KV/m are recommended at residence area and nonresidence area, respectively.

• Journal of the Korean Society of Safety
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• v.11 no.3
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• pp.89-96
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• 1996

This paper presents a study on the analysis and evaluation for ELF( Extremely Low Frequency) electric and magnetic fields under the transmission line according to the power system states. The power system states are classified into two types, normal state resulting from normal operation and alert state from outages. The current in a system is changed continually owing to the load fluctuations even in a normal operation. To calculate the current of the concerned line in a normal state, the system load level is devided into light, base and heavy load level. In case of contingency, an efficient algorithm based on matrix inversion lemma is developed to figure out the current changes. In order to analyze the variations of ELF field caused by the current fluctuations the electrostatic field approach which is far simpler than the electromagnetic field one based on Maxwell equation is introduced in this paper. The suggested method is applied to the IEEE 14 bus system to demonstrate the usefulness.

• Journal of the Korean Society of Safety
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• v.12 no.2
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• pp.70-79
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• 1997

This paper presents a study on the fuzzy linguistic variable based approach for safety assessment of human body in ELF electromagnetic field considering power system states. To cope with the demand in modern industry, the power system becomes larger in scale, higher in voltage. The advent of high voltage system has increased the relative importance of field effects. The analysis of ELF electromagnetic field based on Quasi-Static Method is introduced while the power system is included to model the expected and/or unexpected uncertainty caused by the load fluctuation and parameter changes. In order to analyze the power system, Monte Carlo simulation method and contingency analysis method are adopted in normal state and alert state, respectively. In the safety assessment of human body, the approach based on fuzzy linguistic variable is employed to overcome the shortcomings resulting from a crisp set concept. The suggested scheme is applied to a sample system(modified IEEE 14 bus system) to validate the usefulness.

• Horticultural Science & Technology
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• v.17 no.6
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• pp.773-776
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• 1999

Effects of cacti and a few indoor plants on the protection of the harmful electromagnetic waves (ELF: extremely low frequency and VLF: very low frequency bands) radiated from the monitor of computer were investigated in indoor condition. The front screen of monitor evoked the highest amounts of electromagnetic waves as compared to other positions. Therefore, plants and other objects were placed on the front or side of monitor in order to measure electromagnetic waves. It was shown that all plants including cacti did not have any effect on the reduction of magnetic waves in both ELF and VLF, regardless of species and varieties, sizes, and dispositions. In the case of electric waves, however, there was a little reduction by cacti, depending upon several treatments mentioned before, but the measured values did not reach below values ruled by TCO (Tjatemannens Central Organization, Swedish Confederation of Professional Employees; electric field: 10 V/m and 1 V/m in ELF and VLF, respectively).

• Archives of Pharmacal Research
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• v.26 no.6
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• pp.487-492
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• 2003

This study investigated the effects of extremely low frequency magnetic fields (ELF-MFs) on the sensitivity of seizure response to bicuculline, picrotoxin and NMDA in mice. The mice were exposed to either a sham or 20 G ELF-MFs for 24 hours. Convulsants were then administered i.p. at various doses. The seizure induction time and duration were measured and lethal dose ($LD_{50$}) and convulsant dose ($CD_{50}$) of the clonic and tonic convulsion were calculated. The analysis of glutamate, glycine, taurine and GABA of mouse brain was accomplished by HPLC. The mice exposed to ELF-MFs showed moderately higher $CD_{50}.{\;}LD_{50}$ and onset time on the bicuculline-induced seizure. However, the ELF-MFs did not influence them in the NMDA and picrotoxin-induced seizures. After the exposure to MFs exposure, the glutamate level was increased and GABA was decreased significantly in NMDA and picrotoxin-induced seizure. The level of glutamate and GABA were not changed by MFs in bicuculline-induced seizure. These results suggest that ELF-MFs may alter the convulsion susceptibility through GABAergic mechanism with the involvement of the level of glutamate and GABA.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.10
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• pp.485-491
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• 2002

Since Wertheimer and Leeper reported possible adverse health effects of magnetic field in 1979, worldwide researches on this issue have been conducted. More recently, the U.S. Congress instructed the NIEHS (National Institute of Environmental Health Sciences), NIH (National Institute of Health) and DOE (Department of Energy) to direct and manage EMF RAPID (Electric and Magnetic Fields Research and Public Information Dissemination) program aimed at providing scientific evidence to clarify the potential for health risks from exposure to extremely low frequency electric and magnetic fields(ELF-EMF). Although they concluded that the scientific evidence suggesting adverse health risks of ELF-EMF is weak, the exposure to ELF-EMF cannot be recognized as entirely safe. Therefore, the purpose of this article is to describe magnetic field 3-D calculation and to evluate eddy current of human body compare to international guide line recognized one of the basic problems. In open boundary problem, Magnetic field using FEM is not advantageous in the point of the division of area and the proposition of the fictitious boundary. Therefore, we induced the analytic equation of magnetic field calculations so but the finite line segment based on Biot-Savarts law Also, Eddy currents induced due to ELF-EMF magnetic field are computed. To calculate induced currents, impedance method is used in this paper, An example model of human head with resolution of 1.27cm is used. In this paper, We evaluate the magnetic field and eddy current of human head around 765 kV transmission lines compare to international guide line.

• Journal of Gastric Cancer
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• v.3 no.3
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• pp.122-127
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• 2003

Purpose: The incidence rate and the mortality rate of gastric cancer have decreased in developed countries over the last several decades. On the other hand, they remain high in far eastern countries such as Korea, Japan, China and in many developing countries. The cure of patients with gastric carcinomas can be achieved mostly through complete surgical resection, but most gastric cancer patients are in advanced stages when diagnosed and have poor prognoses. therefore, the development of an effective systemic therapy is essential for far advanced gastric cancer patients. Until recently, the most commonly used combination chemotherapy was based on 5-flurouracil or cisplatin, but the results were not satisfactory, so recently etoposide, adriamycin and cisplatin (EAP-II) combination chemotherapy was introduced in patients with advanced gastric cancer. Early studies showed a high response rate and the ability to convert unresectable cases to resectable ones, but later studies couldn't duplicate the result. the purpose of this study was to evaluate the relative efficacy & toxicity of EAP-II chemotherapy and ELF chemotherapy which is based on 5-flurouracil. Materials and Methods: Between July 1992 and July 2002, sixty-five patients with inoperable advanced gastric cancer were enrolled for this study. Thirty-seven patient received EAP-II chemotherapy:etoposide (20 mg/$m^{2}$ IV for $1\∼5 days$), adriamycin (20 mg/$m^{2}$ IV for $1\∼5 days$) and cisplatin (20 mg/$m^{2}$ IV for $1\∼5 days$) and Twenty-eight patients receieved ELF chemotherapy : etoposide (100 mg/$m^{2}$ IV for $1\∼3 days$), leucovorin (20 mg/$m^{2}$ IV for $1\∼5 days$) and 5-FU (500 mg/$m^{2}$ IV for $1\∼5 days$). Each treatment schedule for each group was repeated every four weeks: EAP-II means 3.4 cycles per patient..ELF means 4.1 cycles per patient Results: Total respones rates were $5.4\%$ in the ELF group and $3.6\%$ in the EAP group (P-value>0.05). The median times to progression were 144 days in the ELF group and 92 days in the EAP-II group (P-value<0.05), and themedian overall survival times were 189 days in the ELF group and 139 days in the EAP-II group (P-value>0.05). The difference in the survival curves for the two regimens was not statistically significant. Non-hematologic toxicitis & hematologic toxicitis were more frequently observed for the EAP-II regimen. Anemia: $27.6\%$ in ELF vs $54\%$ in EAP-II; Leukopenia: $8.5\%$ in ELF vs $19\%$ in EAP-II; nausea & vomiting: $45.9\%$ in ELF vs $67.8\%$ in EAP-II. Conclusion: EAP-II regimen is not superior to ELF regimen in the tratment of inoperable advanced gastric cancer (J Korean Gastric Cancer Assoc 2003;3:122-127)

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1997.11a
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• pp.117-122
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• 1997

This paper presents a study on the fuzzy based approach for the safety assessment of human body under ELF electric and magnetic(EM) field considering power system states. The analysis of ELF EM field based on quasi-static method is introduced. UP to the present, the analysis of ELF EM field has been conducted with the consideration of one transmission line, or a power line model only In this paper, however, the power system is included to model the expected and/or unexpected uncertainty caused by the load fluctuation and parameter changes and the states are classified into two types, normal state resulting from normal operation and emergency state from outages. In order to analyze the uncertainty in the normal state, the Monte Carlo Simulation, a statistic approach was introduced and line current and bus voltage distribution are calculated by a contingency analysis method, in the emergency state. To access the safety of human body, the approach based on fuzzy linguistic variable is adopted to overcome the shortcomings of the assessment by a crisp set concept. In order to validate the usefulness of the approach suggested herein, the case study using a sample system with 765(kV) was done. The results are presented and discussed.

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.949-961
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• 1997

To date, various clinical procedures have been used to restore periodontal apparatus destroyed by periodontal disease. And then, many experimental approaches have been proceeded to develop treatment methods to promote periodontal regeneration. Mechanical, chemical treatments to enhance the attachment of periodontal tissue cells as changing the physical properties of root surfaces, bone graft procedure, and treatments for guided tissue regeneration have been used for periodontal regeneration. However, recent studies have revealed that biologic factors such as growth factors promote biologic mechanism associated with periodontal regeneration. This study was done to enucleate how ELF stimulus affect the periodontal regeneration. We can have following conclusions from this experimental results. The influence of low frequency(ELF) electric stimulus (30Hz at $lO{\mu}A$) known to promote bone formation in vivo, was evaluated for its ability to affect bone cell function in vitro. After 12 hour exposure of ELF stimulus at most appropriate densities ($5{\times}10^4\;cells/cm^2$) to increase osteoblastic cells normally, rat calvarial cells were incubated for 60 hours were used in this study. We have found ELF stimulus suppress calvarial cell proliferation and the ability of protein synthesis, enhance the alkaline phosphatase activity significantly.

• The Plant Pathology Journal
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• v.40 no.5
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• pp.559-567
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• 2024

Continuous use of synthetic fungicides has led to explosive emergence of fungicide-resistant microbes. Therefore, there are urgent needs for environmentally friendly antimicrobial agents with novel modes of action. This study investigated endolichenic fungi (ELF) as a source of antimicrobial compounds against various plant pathogens. We utilized an One Strain MAny Compounds (OSMAC) approach to enhance the chemical diversity of fourteen ELF. This involved cultivation of ELF in four growth media and subsequently assessing antimicrobial activities of culture extracts. Nearly half of the culture extracts exhibited antimicrobial activity against a Gram-positive bacterium, but showed minimal activity against Gram-negative bacteria tested. Notably, culture extracts from two ELF, Chaetomium globosum and Nodulisporium sp., demonstrated significant inhibitory effects against plant pathogenic fungi. LC-MS/MS-based metabolome profiling confirmed the presence of known bioactive compounds like cyclic dipeptides and chaetoglobosins. These findings highlight the effectiveness of combining OSMAC and metabolomics for identifying antimicrobial agents for agricultural use.