• 한국대기환경학회지
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• 제29권4호
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• pp.439-446
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• 2013

In this research, the present standard analytical methods for the monitoring of air pollution levels established by the Korean Ministry of Environment (KMOE) were examined in reference to the recent outputs of several research projects conducted for their amendments. The evaluation of the two criterion methods between the main (the present guideline) and reference methods (the proposed alternate guideline) was made in terms of authenticity and reliability of the quality assurance (QA) and of compatibility of methods. The results of this comparative evaluation are presented for the analysis of both ambient air and source samples. Based on this analysis, we propose a new direction for the future amendment.

• The Journal of the Acoustical Society of Korea
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• 제29권2E호
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• pp.100-106
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• 2010

Multiple-model speech recognizer has been shown to be quite successful in noisy speech recognition. However, its performance has usually been tested using the general speech front-ends which do not incorporate any noise adaptive algorithms. For the accurate evaluation of the effectiveness of the multiple-model frame in noisy speech recognition, we used the state-of-the-art front-ends and compared its performance with the well-known multi-style training method. In addition, we improved the multiple-model speech recognizer by employing N-best reference HMMs for interpolation and using multiple SNR levels for training each of the reference HMM.

• 동아시아식생활학회지
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• 제16권2호
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• pp.145-155
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• 2006

This study investigated the correlation of the nutritional status of antioxidant vitamins and serum lipids and MDA levels in postmenopausal women. Data about general characteristics, dietary intakes and biochemical parameters, including serum lipids, MDA and antioxidant vitamins levels, were collected from 85 postmenopausal women. The subjects were classified into three groups according to their serum total cholesterol level: normocholesterolemia group (NC, < 200 mg/dL), moderate hypercholesterolemia group (MC, $200{\sim}239mg/dL$) and hypercholesterolemia group(HC, ${\geq}240mg/dL$). The results are as follows. 1) General characteristics and serum MDA levels were not significantly different among the three groups. 2) Daily nutrients intakes adjusted to energy intake were not significantly different among the three groups, and were compatible with dietary reference intakes (DRIs) for Koreans. 3) Dietary Vt. A, ${\beta}-carotene$, Vt. C and Vt. E intake were not significantly different among the groups, while Vt. E intake was positively related with serum TC (r=0.288, p<0.05) and triglyceride (r=0.341, p<0.001) levels. 4) Serum Vt. A level standardized by serum TC level was significantly low and serum Vt. E level was significantly high in the HC group. Serum Vt. E level was positively related with serum TC level (r=0.389, p<0.001). 5) Dietary Vt. E intake was negatively correlated to serum MDA level (r=-0.242 p<0.05). Serum Vt. C and Vt. E levels were also negatively correlated to serum MDA level (r=-0.312, p<0.001 and r=-0.299, p<0.05). When the correlation was analyzed only in the group with hypercholesterolemia, correlation coefficients between the antioxidant vitamin and serum MDA level were higher. We concluded that intakes of antioxidant vitamins can contribute to decreasing the risk of cardiovascular disease by decreasing the oxidative stress of body rather than by controlling serum lipid levels.

• 한국환경보건학회지
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• 제42권3호
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• pp.213-223
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• 2016

Objectives: This study was designed to assess the level of physical exposure to heavy metals among residents who live around a Chungcheongnam-do Province industrial complex and to provide baseline data on the effects and harms of heavy metals on the human body by comparing their exposure levels to those of people from control regions. Methods: We measured blood lead and cadmium levels and urine mercury and chromium levels and conducted a survey among 559 residents from the affected area and 347 residents of other areas. Results: Blood lead and cadmium levels and urine mercury levels were significantly higher in the case region than among those in the control region (p=0.013, p<0.001, p<0.001, respectively). In the thermoelectric power plant area, blood cadmium and urine mercury levels were significantly higher than in the control region (p<0.001, p<0.001, respectively). In the steel mill and petrochemical industry areas, blood cadmium level was significantly higher than that in the control region (p<0.001). Dividing groups by the reference level of blood cadmium ($2{\mu}g/L$), the odds ratios between the case and control regions were 2.56 (95% CI=1.83-3.58), 3.11 (95% CI=2.06-4.71) for the thermoelectric power plant area, 1.78 (95% CI=1.19-2.65) for the steel mill area and 4.07 (95% CI=2.40-6.89) for petrochemical industry area. Conclusion: This study showed that the levels of exposure to heavy metals among residents living near a Chungcheongnam-do Province industrial complex were significantly higher than those in the control region. This seems to be attributable to exposure to heavy metals emissions from the industrial complex. Further research and safety measures are required to protect residents' health.

• 생태와환경
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• 제40권4호
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• pp.569-575
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• 2007

This study was carried out to determine bioaccumulation levels of total mercury on various fish tissues in two streams (Banseok and Hasin Stream) and one lake (Yeongsan Lake) during April-May 2007. We also determined natural background levels of total mercury bioaccumulation to evaluate relative individual impacts of fish and compared the levels with reference sites as a preliminary study to evaluate heavy metal stressor using fish. For the study, we collected fishes in the sampling sites and analyzed the concentrations of total mercury in the liver, kidney, gill, vertebral column, and muscle tissues using Direct Mercury Analyzer (DMA-80, US EPA Method 7473). The levels varied depending on the types of waterbody and tissues used. Concentrations of total mercury ranged between 5.1${\mu}g$ $kg^{-1}$ and 108.6 ${\mu}g$ $kg^{-1}$ in the streams and between 5.3${\mu}g$ $kg^{-1}$ and 87.3 ${\mu}g$ $kg^{-1}$ in the reservoir, and the values were highest in the muscle tissues. Levels of natural background levels of total mercury, even though the sampling number was few, averaged 23.6 ${\mu}g$ $kg^{-1}$ in the study sites. The individual and mean values in each system was not so high in terms of US EPA criteria of fish health and human health, indicating that the impact was minor in the study site. Further studies should be done for the determination of mercury levels in the systems.

• 대한임상검사과학회지
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• 제37권1호
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• pp.56-60
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• 2005

Human chorionic gonadotrophin (hCG) and unconjugated estriol (uE3) were added to AFP to make what is commonly known as the Triple test. The Triple test combines results from these three tests and has been a standard screening procedure for several years. Recent studies have demonstrated the usefulness of adding inhibin-A to Down's syndrome risk assessment. The Quad test adds dimeric Inhibin-A (DIA) to the three other markers and uses the same computer program to calculate risk factors. Testing was performed between 14 and 21 weeks of gestation. Sample size were 648 samples and period of study was from 1, July, 2004 to 30, September, 2004. Used analytical methods for AFP, hCG and uE3 were radioimmunoassay (RIA) and dimeric inhibin A was enzyme-linked immunosorbent assay (ELISA). Adding dimeric inhibin-A as a fourth marker to the standard triple test increases the detection rate from 62 % to 75 % with a false-positive rate of 5%. The DIA based Quad test has been shown to be the most effective second trimester screening test for Down's syndrome suitable for routine use. Increased DIA values are observed during normal pregnancy where a bimodal pattern response is seen. Values increase during the first trimester, decline after 14 weeks, and re-ascend between 17-25 weeks. Values for DIA may be additionally elevated during a Down's syndrome pregnancy. Dimeric inhibin A is a glycoprotein hormone made by the ovary and placenta. DIA levels are twice as high in Down's syndrome pregnancies. AFP, hCG, and uE3 levels vary with gestational age, and incorrect gestational dating will influence results. DIA levels do not vary substantially with gestational age, resulting in greater screening accuracy. Although the Quad test is an improvement over the Triple test, it is important to underscore the fact that a positive test on both should be done. Most women who initially screen positive will be found to be carrying normal babies when amniocentesis and definitive diagnostic chromosome analysis are done.

• 한국환경보건학회지
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• 제38권1호
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• pp.51-56
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• 2012

Objectives: High concentrations of airborne particulate matters (PM) can affect the health of passengers using public transportation. The objectives of this research were to develop a PM control system for a railway cabin and to evaluate the performance of the device under conditions of an actual journey. Methods: This study measured the concentrations of $PM_{10}$ and $PM_{2.5}$ simultaneously in a reference cabin and a cabin with the PM control device. Results: The average $PM_{10}$ concentration in the reference cabin was 100 ${\mu}g/m^3$, and the $PM_{10}$ concentration in the cabin with the control device was 79 ${\mu}g/m^3$. While the overall control efficiency of the control device was 15.4%, reduction was more effective for peak $PM_{10}$ concentration. However, $PM_{2.5}$ levels did not differ greatly between the reference cabin and the cabin with the control device. The ratio of $PM_{2.5}$ to $PM_{10}$ was 0.37. $PM_{10}$ concentrations in cabins were not associated with ambient concentrations, indicating that the main sources of $PM_{10}$ were present in cabins. Additionally, average $CO_2$ concentration in the cabins was 1,359 ppm, less than the maximum of 2,000 ppm set out by the Korean Ministry of Environment's guideline. The $CO_2$ concentration in cabins was significantly associated with the number of passengers: the in-cabin concentration = $23.4{\times}N+460.2$, where N is the number of passengers. Conclusions: Application of the PM control device can improve $PM_{10}$ concentration, especially at peak levels but not $PM_{2.5}$ concentration.

• Journal of Preventive Medicine and Public Health
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• 제33권1호
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• pp.45-50
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• 2000

Objectives : This study was undertaken to evaluate correlation between the levels of hippuric acid in blood plasma (HAP) and those of toluene concentration in the workplace air. Methods : Study subjects were composed of two groups; 21 workers who were occupationally exposed to toluene and 25 rural-area residents who were not exposed to any known occupational toluene source, as an exposed group and a reference group, respectively. Mean age and work duration of the exposed was 42 years and five years, respectively. Mean age of the reference was 42 years. To determine toluene concentrations in the workplace air, air sampling has been conducted for more than six hours using a personal sampler, and analyzed by a gas chromatography-flame ionization detector. Concentrations of hippuric acid in biological samples were determined by a high performance liquid chromatography-ultraviolet detector. Results : Geometric mean(geometric standard deviation) of HAP and hippuric acid in urine(HAU) for the exposed was 1.39(2.21) mg/L and 2.77(1.46) g/L, respectively, which were significantly different from those of the reference [HAP, 9.45(2.94); HAU, 0.37(0.45)]. Teluene concentration in the workplace air was 86.92(range: $45.18\sim151.23$)ppm. The level of HAP or HAU was significantly correlated (r=0.70 and r=0.63, respectively) with that of toluene in the workplace air. The estimated regression equation was logHAP(mg/L)=-3.60+1.93 log(toluene, ppm) or logHAU(g/L)=-0.85+0.67 log(toluene, ppm). The magnitude of correlation was further enhanced when analyzing relationship between toluene concentrations lower than 100 ppm and its corresponding HAP levels. Conclusion : Overall, plasma hippuric acid levels were well correlated with toluene concentrations in the workplace air, and a statistically significant correlation was observed for the samples with toluene concentration lower than 100 ppm.

• 한국방사선학회논문지
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• 제15권2호
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• pp.117-123
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• 2021

본 논문에서는 흉부 저선량 CT와 복부 비조영 CT에서 선량기록을 바탕으로 환자선량에 영향을 줄 수 있는 요인과 상관관계를 확인하여 실질적인 선량 감소 방안의 근거를 마련하고자 하였다. 흉부 저선량 CT와 복부 비조영 CT 검사 시 불필요하게 피폭이 발생하는 원인을 찾기 위해 7가지 요인(나이, 성별, 키, 몸무게, BMI, 환자 상태 (입원, 외래), dose modulation 활성화 유무)과 CT 선량과의 상관관계를 확인하였다. 상관관계 확인을 위해 사용된 통계기법으로는 로지스틱 회귀분석을 사용하였다. 흉부 저선량 CT 검사에서는 키가 클수록, BMI 가 높을수록, dose modulation을 비활성화한 경우에 진단참고수준 (diagnostic reference levels, DRL) 기준치의 초과 위험률이 낮아졌다 (odds ration<1; p<0.05). 또한 여성의 경우와 몸무게가 클수록 DRL 기준치의 초과 위험률이 높아졌다 (odds ration>1; p<0.05). 복부 비조영 CT 검사에서는 몸무게가 클수록, dose modulation을 비활성화한 경우에 DRL 기준치의 초과 위험률이 낮아졌다 (odds ration<1; p<0.05). 이처럼 방사선 피폭에 영향을 주는 다양한 요인에 대한 연구를 수행하여 환자 선량과의 연관성을 찾고 이에 따른 선량을 낮추는 노력이 필요할 것으로 사료된다.

• 대한임상검사과학회지
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• 제50권1호
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• pp.1-10
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• 2018

갑상선의 기능적 발달 이전인 임신초기에 갑상선자극호르몬은 갑상선 장애 및 임신 동안 매우 민감한 지표이다. 임신동안 정상수준은 감소 변화를 보이는 것은 모체로부터 태아가 받는 갑상선호르몬의 영향이다. 갑상선자극호르몬과 유리 티록신의 농도는 임신동안 및 검사실간에 다양하게 보고된다. 갑상선자극호르몬의 참고치는 비임신군에 비하면 상한값과 하한값의 참고범위의 감소가 임신동안 보인다. 각 실험실은 임신 중에 다른 결과를 산출하는 호르몬 분석법과 일부 자체 기준에 맞는 혈중 농도를 산출한다. 따라서, 혈청 유리 티록신 분석에 사용되는 자동화 된 면역 분석법은 여전히 널리 사용되고 있지만 고려할 사항이 있다. 집단 기준, 삼분위 기간별 특이적 참고범위 사용은 문제해결의 최상의 방법이다. 임신 7~12주에 발생하는 호르몬의 하향은 7주 이전에는 보이지 않아 참고범위의 개별적 정량적으로 상승 및 하강을 보여준다. 본 연구에서는 집단별과 임신 특이적 갑상선 매개 변수의 참조범위에 대한 산출 중요성을 강조한다. 정밀의학 의 도래에 있어서 많은 개체의 유전적, 생물학적, 심리사회학적, 환경적 변수를 수집하고 분석이 필요하다. 이러한 논쟁을 해결하기 위해서는 다량의 전향적인 무작위 통제 연구가 필요하다.