• Asian-Australasian Journal of Animal Sciences
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• v.32 no.6
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• pp.815-825
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• 2019

Objective: To effectively use corn stover resources as animal feed, the changes in microbial population and chemical composition of corn stover during field exposure, and their silage fermentation and in vitro digestibility were studied. Methods: Corn cultivars (Jintian, Jinnuo, and Xianyu) stovers from 4 random sections of the field were harvested at the preliminary dough stage of maturity on September 2, 2015. The corn stover exposed in the field for 0, 7, 15, 30, 60, 90, and 180 d, and their silages at 60 d of ensiling were used for the analysis of microbial population, chemical composition, fermentation quality, and in vitro digestibility. Data were analyzed with a completely randomized $3{\times}6$ [corn stover cultivar $(C){\times}exposure$ d (D)] factorial treatment design. Analysis of variance was performed using SAS ver. 9.0 software (SAS Institute Inc., Cary, NC, USA). Results: Aerobic bacteria were dominant population in fresh corn stover. After ensiling, the lactic acid bacteria (LAB) became the dominant bacteria, while other microbes decreased or dropped below the detection level. The crude protein (CP) and water-soluble carbohydrate (WSC) for fresh stover were 6.74% to 9.51% and 11.75% to 13.21% on a dry matter basis, respectively. After exposure, the CP and WSC contents decreased greatly. Fresh stover had a relatively low dry matter while high WSC content and LAB counts, producing silage of good quality, but the dry stover did not. Silage fermentation inhibited nutrient loss and improved the fermentation quality and in vitro digestibility. Conclusion: The results confirm that fresh corn stover has good ensiling characteristics and that it can produce silage of good quality.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.4
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• pp.310-321
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• 2007

Status of benzene exposure was evaluated upon petrochemical workers in the Yeosu Industrial Complex, based on questionnaire responses by workers, review of previous work environment assessment reports between 1996 and 2004, in addition to short-term exposure measurements for unit tasks in the field. Questionnaire results showed that workers in the field were suffering concern on and symptoms of respiratory diseases, cancers or other illnesses of unknown causes. In particular, workers were highly worried about the risk of exposure to chemical hazards including benzene, while conducting specific tasks (e.g. sampling, draining, gauging) among normal operations during which equipments are opened and contents are exposedin the air, as well as periodic turnaround (TA) task. However, the review of previous work environment assessment reports found out that short-term exposure assessment data for unit tasks accounted for less than 1% of total data, and most of them were on 8-hr average exposure level. It also turned out that benzene was not detected in 83% of total samples, suggesting routine but pointless sampling has been repeated. Short-term exposure level was assessed focusing on tasks with high level of complaints on the exposure risk, based on the questionnaire responses. As predicted, a maximum of 741 ppm benzene exposure was reached depending on types and conditions of operations involved. In conclusion, these findings suggest that the evaluation and management on the short-term high exposure tasks including turnaround are crucial in reducing benzene exposure and preventing haematopoietic cancer in workers in the petrochemical industry.

• Journal of Life Science
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• v.25 no.2
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• pp.151-157
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• 2015

Zebrafish (Danio rerio) has been more widely used to study pharmacology. Oxytectracycline (OTC) is a broad-spectrum antibiotic and works by interfering with the ability to produce essential proteins of bacteria. The aim of this study was to identify the effects of exposure to OTC on behavioral changes or endocrine response in zebrafish. The behavioral effects of exposure to OTC (50, 100 or 200 mg/l) were characterized in several novelty-based paradigms such as the novel tank or open field test in zebrafish. Moreover, to investigate effects of exposure to OTC on endocrine response, we measured whole-body cortisol level using cortisol ELISA kit. As results of novel tank test, duration in top and immobile duration were significantly increased by the exposure to OTC in a concentration-dependent manner (p<0.05). In addition, moving distance, highly mobile, velocity and zone transition were significantly decreased by the exposure to OTC in a concentration-dependent manner (p<0.05). As results of open field test, the exposure to OTC increased immobile duration significantly (p<0.05). However, moving distance, mobile duration and velocity were significantly decreased by the exposure to OTC in a concentration-dependent manner (p<0.05). Besides, the exposure to OTC elevated whole-body cortisol levels in zebrafish. These results suggest that the exposure to OTC may induce chemical stress in zebrafish.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.3
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• pp.264-274
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• 2012

Evaluation on the environmental noise is carried out by surveying subjective response of residents with physical measurement of noise during long period in field. Particularly field survey is used to make regulations from the analysis on how many people are annoyed for specific noise level, and laboratory test used to analyze the relationship between physical parameters of noise and subjective responses. In the laboratory controlling the variables is easy but the results could be biased because the condition in room would be different with field. Most of all noise exposure time is considered to be different with real situation, and this study aimed to evaluate the subjective response by exposure time of transportation noise, by applying three kinds of variable how much they give effects on the annoyance as the exposure time is operating condition, windows type and sound level. As a result there was somewhat difference between operating type and annoyance, which is caused by the sound characteristics operated in different condition. However the window type didn't give much effect to the annoyance as much as sound type. This means that the subjective response could give similar result by exposure time even for different window types. Most of all, the main factor affecting subjective response is considered to be the sound level and the exposure time.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.241-250
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• 2011

The safety of human exposure to an ever-increasing number and diversity of electromagnetic field (EMF) sources both at work and at home has clearly become a public health issue. To date many $in$ $vivo$ and $in$ $vitro$ studies revealed that EMF exposure can alter cellular metabolism, endocrine function, immune activity, reproductive function, and fetal development in animal system. The major parameters found to be altered in cells or individuals following EMF exposure include an increase of free radicals, DNA damage, cancer risk, developmental defect, and reproductive dysfunctions. Epidemiological studies reported EMF can increase life-threatening illnesses such as leukemia, brain cancer, amyotrophic lateral sclerosis, clinical depression, suicide, and Alzheimer's disease has been identified. These effects of EMF exposure differ according to duration of exposure, frequency of waves, and strength (energy) of EMF. In the present review, we briefly introduced the physical properties of EMF and summarized the effect of EMF on human and wildlife animals according to types of EMF, duration of exposure at cellular and organism levels.

• The Korean Journal of Pain
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• v.33 no.1
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• pp.73-80
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• 2020

Background: The aim of this study was to evaluate radiation exposure to the eye and thyroid in pain physicians during the fluoroscopy-guided cervical epidural block (CEB). Methods: Two pain physicians (a fellow and a professor) who regularly performed C-arm fluoroscopy-guided CEBs were included. Seven dosimeters were used to measure radiation exposure, five of which were placed on the physician (forehead, inside and outside of the thyroid protector, and inside and outside of the lead apron) and two were used as controls. Patient age, sex, height, and weight were noted, as were radiation exposure time, absorbed radiation dose, and distance from the X-ray field center to the physician. Results: One hundred CEB procedures using C-arm fluoroscopy were performed on comparable patients. Only the distance from the X-ray field center to the physician was significantly different between the two physicians (fellow: 37.5 ± 2.1 cm, professor: 41.2 ± 3.6 cm, P = 0.03). The use of lead-based protection effectively decreased the absorbed radiation dose by up to 35%. Conclusions: Although there was no difference in radiation exposure between the professor and the fellow, there was a difference in the distance from the X-ray field during the CEBs. Further, radiation exposure can be minimized if proper protection (thyroid protector, leaded apron, and eyewear) is used, even if the distance between the X-ray beam and the pain physician is small. Damage from frequent, low-dose radiation exposure is not yet fully understood. Therefore, safety measures, including lead-based protection, should always be enforced.

• Journal of radiological science and technology
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• v.44 no.6
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• pp.591-597
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• 2021

In the present study, we developed virtual reality education contents for radiation generator on radiation education field. The radiation generator was divided by module and even the X-ray exposure part was manufactured in detail for designing 3D models. The mechanical details of the X-ray exposure part, the function of adjusting field size of the X-ray, the function of moving the exposure part, and the demonstrating the principle of the X-ray tube were applied. For developing VR contents, the Unreal Engine was used. To evaluate the usefulness of virtual reality content, we used t-test by SPSS. The group used the simulator showed significantly higher levels of understanding of X-ray generation, X-ray irradiation unit composition, irradiation field size adjustment, irradiation unit position adjustment, and overall composition and function. We believe that this VR contents will be used well with radiation safe environment.

• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.267-275
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• 2023

Occupational exposure records are subject of global interest, and analysis of radiation workers in work categories is being conducted. In Rep. of Korea, according to relevant ministries, the MOHW(Ministry of Health and Welfare), the MAFRA(Ministry of Agriculture, Food and Rural Affairs), and the NSSC(Nuclear Safety and Security Commission) collect and analyze records of occupational exposure by dividing them into 11 work categories. However, this classification system lacks consistency with the systems of major countries, including the UNSCEAR(United Nations Scientific Committee on the Effects of Atomic Radiation). The domestic radiation work field classification system does not have clear classification criteria and does not reflect the characteristics of the radiation work field. Through the analysis of the classification system of the UNSCEAR, we suggested the five main categories(nuclear cycle, medical, industrial, others(education/research, military/public) field and several sub-categories according to each radiation work field.

• Nuclear Engineering and Technology
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• v.38 no.5
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• pp.449-454
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• 2006

Neutron imaging technique was used to investigate the water distribution and movement in Polymer Electrolyte Membrane Fuel Cell (PEMFC) at HANARO, KAERI. The Feasibility tests were performed in the first and second exposure rooms at the neutron radiography facility (NRF) at HANARO in order to check the ability of each exposure room, respectively. The feasibility test apparatus was composed of water and pressurized air before making up the actual test apparatus. Due to the low neutron intensity in the second exposure room, the exposure time was too long to investigate the transient phenomena of PEMFC. Although the exposure time was improved to 0.1 sec in the first exposure room, it was difficult to discriminate detail water movement at the channel due to the high noise level. Therefore, the experimental setup must be optimized according to the test conditions. Water discharge characteristics were investigated under different flow field geometries by using feasibility test apparatus and the neutron imaging technique. The water discharge characteristics of a 3-parallel serpentine are superior to those of a 1-parallel serpentine, but water at Membrane Electrode Assembly (MEA) was not removed, regardless of the flow field type.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.6
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• pp.606-615
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• 2003

This study examined the effects of exposure to the electromagnetic field emitted by mobile phone on human cognitive function. Total volunteers were twenty and volunteers were separated in two groups. One is teenager group, and the other is adult group. Test was performed in the counterbalanced order(sham-real, real-sham). Subject remained blind to mobile phone status during the exam. The result showed that the exposure to the electromagnetic field significantly speeded up response time fur teenager group. This results suggest that exposure to the electromagnetic field emitted by cellular phones may have a mild facilitating effect on cognitive function in teenager group.