• Asian-Australasian Journal of Animal Sciences
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• 제32권6호
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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.

• 한국산업보건학회지
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• 제17권4호
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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.

• 생명과학회지
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• 제25권2호
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• pp.151-157
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• 2015

Zebrafish는 약리학 연구에 널리 사용되는 실험 동물 중 하나이다. Oxytetracycline은 넓은 항균 범위를 가지는 항생제로써 단백질 합성을 억제하여 정균 작용을 가진 항생제이다. 본 연구의 목적은 OTC에 노출이 되었을 때 zebrafish에게서 나타나는 행동변화와 내분비계의 변화를 관찰하였다. OTC (50, 100 or 200 mg/l)에 노출된 zebrafish의 행동변화를 확인하기 위해 novel tank test와 open field test를 진행하였다. 또한 내분비계의 변화를 확인하기 위하여 whole-body cortisol의 수치를 cortisol kit를 이용하여 측정하였다. Novel tank test 결과 상층부에서 머문 시간과 부동 시간에서 OTC를 약욕하였을 때 통계적으로 유의성이 있는 증가현상이 확인되었다. 반면에, 총 이동거리, 과행동 시간, 유영 속도 그리고 상하 변위에서 OTC를 약욕하였을 때 통계적으로 유의성 있는 감소 현상이 확인되었다. Open field test 결과 부동시간에서 OTC를 약욕 하였을 때 통계적으로 유의성 있는 증가 현상이 확인 되었다. 그러나 OTC를 약욕 하였을 때 총 이동거리, 움직인 시간, 유영 속도에서 통계적으로 유의성이 있는 감소 현상이 확인 되었다. Whole-body cortisol에서는 zebrafish에게 약욕을 하였을 때 증가하는 경향이 관찰되었다. 이러한 결과를 통하여 OTC가 zebrafish에게 화학적 스트레스로 작용한 것으로 사료된다.

• 한국소음진동공학회논문집
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• 제22권3호
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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.

• 환경생물
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• 제29권4호
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• pp.241-250
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• 2011

현대인들은 가정생활과 직업환경 속에서 다양한 종류의 전자기파에 노출되며 전자기파 노출에 따른 생체위해성은 공중보건학적으로 중요한 이슈로 대두되었다. 현재까지 많은 체외 및 체내실험 결과에서 전자기파 노출이 세포대사, 내분비, 면역, 신경, 생식, 태아발달에 영향을 미치는 것으로 보고되었다. 세포나 개체 수준에서 시행된 실험연구에서는 전자기파 노출에 의해 세포내부 자유기의 증가, DNA 손상과 암발생, 발생기형, 생식기능 저하가 나타난다. 역학조사결과 전자기파 노출은 생명을 위협하는 질병인 백혈병, 뇌암, 근위축성 측삭경화증, 우울증, 자살, 알츠하이머와 상관성이 보고되었다. 이러한 생체기능 변화는 전자기파의 주파수, 노출기간, 강도 (에너지)에 따라 다르게 나타난다. 전자기파 노출은 곤충, 어류, 양서류, 파충류, 조류 등 야생동물에서도 동물행동, 번식, 생리기능의 변화를 초래한다. 본 소고에서는 인간보건학적 측면과 생태계에서 나타난 전자기파의 위해성을 전자기파의 종류, 노출시간에 따라 세포 및 개체 수준에서 보고된 위해성 자료를 정리하였다.

• The Korean Journal of Pain
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• 제33권1호
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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.

• 대한방사선기술학회지:방사선기술과학
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• 제44권6호
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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.

• 한국방사선학회논문지
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• 제17권2호
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• pp.267-275
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• 2023

전 세계적으로 방사선종사자들의 피폭 기록은 관심의 대상이며 피폭이 일어나는 분야에 대한 분석이 수행되고 있다. 한국에서는 유관부처에 따라 보건복지부, 농림축산식품부, 원자력안전위원회에서 종사자들의 피폭을 11개 업종으로 나누어 기록을 수집 분석하고 있다. 그러나 이러한 분류 체계는 유엔방사선영향과학위원회를 비롯한 주요 국가들의 분류 체계와는 정합성이 부족하다. 국내의 종사자 피폭 분류 체계는 명확한 분류 기준이 없고 업종 특성 등을 반영해주지 못하고 있다. 유엔방사선영향과학위원회의 분류 체계를 바탕으로 국내의 분류 체계를 핵주기 분야, 의료분야, 산업분야, 그 외 분야(교육/연구, 군사/공공)의 5개 대분류 체계와 그에 따른 세 분류 및 직군 분류를 본 연구를 통해 제안하였다.

• Nuclear Engineering and Technology
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• 제38권5호
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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.

• 한국전자파학회논문지
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• 제14권6호
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• pp.606-615
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• 2003

본 연구에서는 일상생활에서 사용하는 휴대폰에서 방출되는 전자파가 인체의 시각 자극 반응에 미치는 영향을 연구하였다. 기존의 국외연구에서는 현재 국내에서 사용되고 있지 않는 아날로그 방식 또는 GSM 방식의 휴대폰을 사용한 연구였으나 본 연구에서는 현재 국내에서 사용되고 있는 CDMA 방식의 휴대폰을 사용하여 시각 자극 반응에 미치는 영향을 평가하였다. 실험은 청소년 집단(10명, 연령:14.3$\pm$1.1세)과 성인 집단(10명, 연령:24.5$\pm$3.4세)으로 구성된 20명의 지원자를 대상으로 실시하였다. 전자파 노출은 실제 휴대폰을 사용하여 이루어졌고, 실제 노출과 허위 노출의 순서에 따른 영향을 없애기 위해 blind test로 노출 순서를 교번시켜서 대등하게 하였다. 실험 결과 CDMA휴대폰에서 방출되는 전자파에 노출되었을 경우 기존의 연구(아날로그 및 GSM방식)에서 제시하는 바와 같이 청소년의 경우에는 자극 반응 속도가 노출군에서 유의하게 빨라짐을 관찰하였다.