• 한국잡초학회지
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• 제30권2호
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• pp.94-102
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• 2010

기온상승 조건을 부여하기 위해 재식시기를 달리하여 재식 한 올방개의 출아와 초기생장을 평가하고 이들과 유효적산온도간의 관계를 수학적 모델로 해석하기 위한 포트 및 포장평가를 수행하였다. Gompertz 모델을 이용하여 이들의 관계를 비선형회귀로 분석한 결과, 파종일자 및 재식 토양심도에 상관없이 유효적산 온도로 누적출아율 및 초기생장을 양호하게 설명하였다. 올방개의 최대 출아율의 50% 도달에 필요한 유효적산온도는 올방개 괴경 재식심도 1, 3 및 5 cm에서 54.5, 84.0 및 $118.0^{\circ}C$이었으며 5엽기에 이르는데 필요한 유효적산온도는 각각 155.3, 188.5 및 $215.5^{\circ}C$이었다. 본 연구에서 개발된 모델식을 이용하여 계산한 결과 평균기온이 $2^{\circ}C$ 상승한 조건에서 올방개의 50 % 출아는 심도에 따라 약 1 - 2일 빨라지고, 5엽기에 도달하는 날짜도 약 2 - 3일 빨라질 것으로 예측되었다. 따라서 $2^{\circ}C$ 기온상승 조건에서 올방개를 효과적으로 방제하기 위해서는 현재의 제초제 처리시기보다 약 2 - 3일 빨라져야 할 것으로 판단된다.

• 한국환경보건학회지
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• 제30권2호
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• pp.140-148
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• 2004

To evaluate the acute effects of fine particles on pulmonary function, a longitudinal study was conducted. This study was carried out for the schoolchildren (3rd and 6th grades) living in Beijing, China. Each child was provided with a mini-Wright peak flow meter and a preformatted health symptom diary for 40 days, and was trained on their proper use. Participants were instructed to perform the peak flow test three times in standing position, three times a day (9 am, 12 pm, and 8 pm), and to record all the readings along with the symptoms (cold, cough, and asthmatic symptoms) experienced on that day. Daily measurement of fine particles (PM$_{10}$ and PM$_{2.5}$) was obtained in the comer of the playground of the participating elementary school for the same period of this longitudinal study. The relationship between daily peak expiratory flow rate (PEFR) and fine particle levels was analyzed using a mixed linear regression models including gender, height, the presence of respiratory symptoms, and daily average temperature and relative humidity as extraneous variables. The total number of students participating in this longitudinal study was 87. The range of daily measured PEFR was 253-501$\ell$/min. In general, the PEFR measured in the morning was lower than the PEFR measured in the evening (or afternoon) on the same day. The daily mean concentrations of PM$_{10}$ and PM$_{2.5}$ over the study period were 180.2$\mu\textrm{g}$/㎥ and 103.2$\mu\textrm{g}$/㎥, respectively. The IQR (inter-quartile range) of PM$_{10}$ and PM$_{2.5}$ were 91.8$\mu\textrm{g}$/㎥ and 58.0$\mu\textrm{g}$/㎥. During the study period, the national ambient air quality standard of 150$\mu\textrm{g}$/㎥ (for PM$_{10}$) was exceeded in 23 days (57.5%). The analysis showed that an increase of 1$\mu\textrm{g}$/㎥ of PM$_{10}$ corresponded to 0.59$\mu\textrm{g}$/㎥ increment of PM$_{2.5}$. Daily mean PEFR was regressed with the 24-hour average PM$_{10}$ (or PM$_{2.5}$) levels, weather information such as air temperature and relative humidity, and individual characteristics including gender, height, and respiratory symptoms. The analysis showed that the increase of fine particle concentrations was negatively associated with the variability in PEFR. The IQR increments of PM$_{10}$ or PM$_{2.5}$ (at 1-day time lag) were also shown to be related with 1.54 $\ell$/min (95% Confidence intervals: 0.94-2.14) and 1.56$\ell$/min (95% CI: 0.95-2.16) decline in PEFR.R.ine in PEFR.ine in PEFR.

• Imaging Science in Dentistry
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• 제48권2호
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• pp.97-101
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• 2018

Purpose: This study evaluated the radiopacity of contemporary luting cements using conventional and digital radiography. Materials and Methods: Disc specimens (N=24, n=6 per group, ø$7mm{\times}1mm$) were prepared using 4 resin-based luting cements (Duolink, Multilink N, Panavia F 2.0, and U-cem). The specimens were radiographed using films, a complementary metal oxide semiconductor (CMOS) sensor, and a photostimulable phosphor plate (PSP) with a 10-step aluminum step wedge (1 mm incremental steps) and a 1-mm-thick tooth cut. The settings were 70 kVp, 4 mA, and 30 cm, with an exposure time of 0.2 s for the films and 0.1 s for the CMOS sensor and PSP. The films were scanned using a scanner. The radiopacity of the luting cements and tooth was measured using a densitometer for the film and NIH ImageJ software for the images obtained from the CMOS sensor, PSP, and scanned films. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests. Results: Multilink (3.44-4.33) showed the highest radiopacity, followed by U-cem (1.81-2.88), Panavia F 2.0 (1.51-2.69), and Duolink (1.48-2.59). The $R^2$ values of the optical density of the aluminum step wedge were 0.9923 for the films, 0.9989 for the PSP, 0.9986 for the scanned films, and 0.9266 for the CMOS sensor in the linear regression models. Conclusion: The radiopacities of the luting materials were greater than those of aluminum or dentin at the same thickness. PSP is recommended as a detector for radiopacity measurements because of its accuracy and convenience.

• Safety and Health at Work
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• 제8권1호
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• pp.36-41
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• 2017

Background: Police work is generally sedentary although there may be situations that require physical endurance and strength, such as foot chases and arresting suspects. Factors such as excessive body fat can impede an officer's physical ability to deal with such occurrences. Our objective was to examine associations between officers' body fat percentage (BF%) and performance on a standardized fitness protocol. Methods: Data were obtained from fitness screening among 1,826 male and 115 female officers in a large US police agency. The screening consisted of a 2.4-km run, push-ups, sit-ups, and sit-and-reach test. Sex-specific body fat percentages were estimated from skinfold thickness measured using calipers. Linear regression models were used to examine unadjusted and adjusted mean scores of fitness tests across BF% tertiles. Results: The prevalence of overall fitness was 4.3 times greater in male officers and 3.6 times greater in female officers having the lowest BF% tertile compared with the highest tertile (30.3% vs 7.1% and 46.0% vs 12.8%, respectively). BF% was linearly and positively associated with the time of 2.4-km run (p < 0.001), and linearly and inversely associated with the number of push-ups (p < 0.001), sit-ups (p < 0.001), and the distance of sit-and-reach (p < 0.001) in men. Similar associations were observed in women with the exception of sit-and-reach (p = 0.122). Associations were independent of age, race/ethnicity, rank, and duty station. Conclusion: Overall, BF% was inversely associated with fitness levels in male and female officers. Future longitudinal studies should be initiated to explore the potentially causal relationship between BF% and fitness in law enforcement officers.

• Genomics & Informatics
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• 제14권2호
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• pp.62-68
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• 2016

Osteoporosis is a medical condition of global concern, with increasing incidence in both sexes. Bone mineral density (BMD), a highly heritable trait, has been proven a useful diagnostic factor in predicting fracture. Because medical information is lacking about male osteoporotic genetics, we conducted a genome-wide association study of BMD in Korean men. With 1,176 participants, we analyzed 4,414,664 single nucleotide polymorphisms (SNPs) after genomic imputation, and identified five SNPs and three loci correlated with bone density and strength. Multivariate linear regression models were applied to adjust for age and body mass index interference. Rs17124500 ($p=6.42{\times}10^{-7}$), rs34594869 ($p=6.53{\times}10^{-7}$) and rs17124504 ($p=6.53{\times}10^{-7}$) in 14q31.3 and rs140155614 ($p=8.64{\times}10^{-7}$) in 15q25.1 were significantly associated with lumbar spine BMD (LS-BMD), while rs111822233 ($p=6.35{\times}10^{-7}$) was linked with the femur total BMD (FT-BMD). Additionally, we analyzed the relationship between BMD and five genes previously identified in Korean men. Rs61382873 (p = 0.0009) in LRP5, rs9567003 (p = 0.0033) in TNFSF11 and rs9935828 (p = 0.0248) in FOXL1 were observed for LS-BMD. Furthermore, rs33997547 (p = 0.0057) in ZBTB and rs1664496 (p = 0.0012) in MEF2C were found to influence FT-BMD and rs61769193 (p = 0.0114) in ZBTB to influence femur neck BMD. We identified five SNPs and three genomic regions, associated with BMD. The significance of our results lies in the discovery of new loci, while also affirming a previously significant locus, as potential osteoporotic factors in the Korean male population.

• Journal of Biosystems Engineering
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• 제41권4호
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• pp.357-364
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• 2016

Purpose: This study was performed to define the drying characteristics of sorghum by developing thin layer drying equations and evaluating various grain drying equations. Thin layer drying equations lay the foundation characteristics to establish the thick layer drying equations, which can be adopted to determine the design conditions for an agricultural dryer. Methods: The drying rate of sorghum was measured under three levels of drying temperature ($40^{\circ}C$, $50^{\circ}C$, and $60^{\circ}C$) and relative humidity (30%, 40%, and 50%) to analyze the drying process and investigate the drying conditions. The drying experiment was performed until the weight of sorghum became constant. The experimental constants of four thin layer drying models were determined by developing a non-linear regression model along with the drying experiment results. Result: The half response time (moisture ratio = 0.5) of drying, which is an index of the drying rate, was increased as the drying temperature was high and relative humidity was low. When the drying temperature was $40^{\circ}C$ at a relative humidity (RH) of 50%, the maximum half response time of drying was 2.8 h. Contrastingly, the maximum half response time of drying was 1.2 h when the drying temperature was $60^{\circ}C$ at 30% RH. The coefficient of determination for the Lewis model, simplified diffusion model, Page model, and Thompson model was respectively 0.9976, 0.9977, 0.9340, and 0.9783. The Lewis model and the simplified diffusion model satisfied the drying conditions by showing the average coefficient of determination of the experimental constants and predicted values of the model as 0.9976 and Root Mean Square Error (RMSE) of 0.0236. Conclusion: The simplified diffusion model was the most suitable for every drying condition of drying temperature and relative humidity, and the model for the thin layer drying is expected to be useful to develop the thick layer drying model.

• 한국산학기술학회논문지
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• 제14권3호
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• pp.1180-1190
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• 2013

본 연구는 국민건강영양조사 제 4기 2차년도(2008), 3차년도(2009), 제 5기 1차 년도(2010)에 참여한 60세 이상 남성노인 2,763명을 대상으로 대퇴경부 골밀도와 요추골밀도의 골밀도 수준을 파악하고, 신체계측, 생활습관, 식이섭취, 골절 과거력, 골다공증 가족력, 병력 등의 제 요인들과 골밀도의 관련성을 알아보고자 시도하였다. 각 변수의 단위별 BMD의 변화를 표현하기 위해 비율차이 계산식 ${\beta}{\times}$(단위/BMD의평균)를 이용한 다중선형회귀분석을 실시하였다. 모든 연속변수의 단위는 1SD를 사용하였다. 연구결과, 남성노인에서 골다공증 유병률은 60대는 6.7%, 70대는 15.8%, 80대이상은 31.4%이었고, 부위별 골다공증 유병률을 보면, 대퇴 경부부위 유병률은 60대는 2.6%, 70대는 8.2%, 80대이상은 24.8%, 요추부위 유병률은 60대는 5.5%, 70대는 11.3%, 80대이상은 15.4%이었다. 또한 대퇴경부 및 요추 골밀도에 조사된 각 독립변수 중 남성노인의 골밀도에 가장 큰 영향을 미치는 것은 제지방량으로 확인되었다. 따라서 남성노인에서는 제지방량을 늘리는 것이 골다공증을 예방하는 효과적인 방안이 될 것이다.

• Journal of Preventive Medicine and Public Health
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• 제39권4호
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• pp.302-308
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• 2006

Objectives: This study aims to examine if a garbage dumping site has real and negative influence on the quality of life (QOL) for the nearby residents. The net effects of the residential distance from the garbage dumping site and from the garbage truck route were investigated for five domains of the QOL. Methods: Two hundred fifty seven Shin-dong Myeon residents, Chun-cheon Si, participated in a self-administrated survey. The Shin-dong Myeon garbage dumping site began operating in 1996. ANCOV A with generalized linear models and multiple regression analysis were performed. Results: Descriptive analyses show that a residence nearby a garbage dumping site is negatively associated with the physical and environmental domains of the QOL. The residential distance from the garbage truck route does not exert any significant effect on various domains of QOL, except for the environmental domain. On the multivariate analysis, the residents living near the garbage dumping site tended to have a significantly negative QOL in the physical and environmental domains. However, the distance from the garbage truck route did not show a significant nor substantial effect on the QOL. The demographic and socioeconomic control variables are associated with a number of the QOL domains, and their patterns are consistent with the general expectations. Conclusions: The results indicated that a garbage dumping site is considered to be an environmental hazard among the nearby residents according to the lower scores on the physical and environmental domains of the QOL. The findings from this study provide comprehensive understanding on the residents' QOL, and they may help politicians and policy makers make decisions for appropriate interventions.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2016년도 학술발표회
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• pp.260-260
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• 2016

Soil erosion is a very serious problem from agricultural as well as environmental point of view. Various computer models have been used to estimate soil erosion and assess erosion control practice. Universal Soil loss equation (USLE) is a popular model which has been used in many countries around the world. Erosivity (USLE R-factor) is one of the USLE input parameters to reflect impacts of rainfall in computing soil loss. Value of R factor depends upon Energy (E) and maximum rainfall intensity of specific period ($I30_{max}$) of that rainfall event and thus can be calculated using higher temporal resolution rainfall data such as 10 minute interval. But 10 minute interval rainfall data may not be available in every part of the world. In that case we can use hourly rainfall data to compute this R factor. Maximum 60 minute rainfall ($I60_{max}$) can be used instead of maximum 30 minute rainfall ($I30_{max}$) as suggested by USLE manual. But the value of Average annual R factor computed using hourly rainfall data needs some correction factor so that it can be used in USLE model. The objective of our study are to derive relation between averages annual R factor values using 10 minute interval and hourly rainfall data and to determine correction coefficient for R factor using hourly Rainfall data.75 weather stations of Korea were selected for our study. Ten minute interval rainfall data for these stations were obtained from Korea Meteorological Administration (KMA) and these data were changed to hourly rainfall data. R factor and $I60_{max}$ obtained from hourly rainfall data were compared with R factor and $I30_{max}$ obtained from 10 minute interval data. Linear relation between Average annual R factor obtained from 10 minute interval rainfall and from hourly data was derived with $R^2=0.69$. Correction coefficient was developed for the R factor calculated using hourly rainfall data.. Similarly, the relation was obtained between event wise $I30_{max}$ and $I60_{max}$ with higher $R^2$ value of 0.91. Thus $I30_{max}$ can be estimated from I60max with higher accuracy and thus the hourly rainfall data can be used to determine R factor more precisely by multiplying Energy of each rainfall event with this corrected $I60_{max}$.

• 사상체질의학회지
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• 제32권3호
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• pp.33-45
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• 2020

Object Although Taeeum and Soyang constitutional types have bigger body shapes and higher body mass index values than those with the Soeum, the relationship between the Sasang constitutional type and bone mass density is controversial and the association of osteopenia and osteoporosis remains unknown. Therefore, we investigated the relationship between bone mineral density, osteopenia, and osteoporosis according to Sasang constitutional type. Methods A total of 2,508 participants were included in this study. Among the study participants, 1,396 had Taeeum type, 276 had Soeum type, and 836 had Soyang type, respectively. The relationships to bone mass density, osteopenia, and osteoporosis in those with Sasang constitutional type were estimated using logistic and linear regression models. Results Bone mass density was significantly higher in the order of Taeeum, Soyang, and Soeum group (p < 0.01). Soeum group in comparison with Taeeum or Soyang group was significantly associated with a high odds ratio for osteopenia and osteoporosis except in the hip and femoral neck in the comparison of Taeeum and Soeum group (p < 0.01). Moreover, the bone mass density of Soeum group decreased more rapidly as the age increased when compared with Taeeum and Soyang group. Conclusions Our findings may contribute to the early prevention and management of high-risk individuals with poor bone mass density, osteopenia, and osteoporosis using Sasang constitution medicine.