• The Korean Journal of Pain
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• v.34 no.3
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• pp.322-331
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• 2021

Background: The present study employed National Health Insurance Data to explore complex regional pain syndrome (CRPS) updated epidemiology in a Korean context. Methods: A CRPS cohort for the period 2009-2016 was created based on Korean Standard Classification of Diseases codes alongside the national registry. The general CRPS incidence rate and the yearly incidence rate trend for every CRPS type were respectively the primary and secondary outcomes. Among the analyzed risk factors were age, sex, region, and hospital level for the yearly trend of the incidence rate for every CRPS. Statistical analysis was performed via the chi-square test and the linear and logistic linear regression tests. Results: Over the research period, the number of registered patients was 122,210. The general CRPS incidence rate was 15.83 per 100,000, with 19.5 for type 1 and 12.1 for type 2. The condition exhibited a declining trend according to its overall occurrence, particularly in the case of type 2 (P < 0.001). On the other hand, registration was more pervasive among type 1 compared to type 2 patients (61.7% vs. 38.3%), while both types affected female individuals to a greater extent. Regarding age, individuals older than 60 years of age were associated with the highest prevalence in both types, regardless of sex (P < 0.001). Conclusions: CRPS displayed an overall incidence of 15.83 per 100,000 in Korea and a declining trend for every age group which showed a negative association with the aging shift phenomenon.

• Journal of Environmental Health Sciences
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• v.37 no.6
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• pp.418-428
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• 2011

Objectives: The purpose of this study was to examine the cross-sectional relationship between low blood lead levels and increasing blood pressure among Korean adults using a nationally representative sample of the Korean population: the Korea National Health and Nutrition Examination Survey (KNHANES) 2008. Methods: A total of 918 subjects aged 40 and older and not currently being treated for hypertension participated in this study. Information about age, gender, smoking status, alcohol consumption, education level, and the use of anti-hypertensive medication was collected. The blood pressure was defined as the mean of the second and the third measurements after three time measurements. Lead levels were determined by an analysis of blood samples. Multiple linear and logistic regression analyses were implemented after adjusting for covariates including age, gender, educational level, smoking status, alcohol consumption, and BMI. Results: This study showed that the average differences in systolic and diastolic blood pressure comparing the lowest to highest quintile of blood lead were 4.33 mmHg (95% CI, 0.66-8.00; p for trend = 0.027) and 2.66 mmHg (95% CI, 0.26-5.06; p for trend = 0.021), respectively. After multivariate adjustment for covariates, the prevalence odds ratio (POR) of subjects in the highest quintile was associated with a 1.70-fold increase in the risks of hypertension (95% CI, 0.83-3.49; p for trend test = 0.112) over those in the lowest quintile of blood lead concentration, However, it was not statistically significant. Conclusions: This study provided evidence for an association between low- levels of blood lead and elevations in blood pressure and risk for hypertension in the general population of Korea.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.2067-2070
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• 2013

Background/Aim: Stomach cancer is the second most common cause of death from all malignant tumors in the world (third in men, fifth in women), with a strong decreasing trend in most developed countries. The aim of this descriptive epidemiological study was to analyze mortality of stomach cancer in Serbia, excluding the Province of Kosovo, in the 1991-2009 period. Materials and Methods: In data analysis, we used mortality rates which were standardized directly using those of the world population as a standard. In order to analyze the mortality trend from stomach cancer, linear trend and regression analysis were used. Confidence intervals (CIs) for the average age-adjusted and age-specific mortality rates were assessed with 95% level of probability. Mortality data were derived from the data file of the Statistical Office of the Republic of Serbia. Results: During the 1991-2009 period, a significant downward trend in mortality of stomach cancer was recorded in Serbia (y=9.78 - 0.13x, p=0.000; average annual percent change was -6.3 (95%CI, -7.8 to - 4.8). During the same period, a significant decrease in mortality trend was found both in male (y=14.13 - 0.20x; p=0.000; % change was -7.7 (95%CI, -10.9 to -4.5) and female populations (y=6.27 - 0.08x; p=0.000; % change was - 4.4 (95%CI, -5.3 to -3.6). Conclusion: Decreasing trends in mortality from stomach cancer in Serbia are similar to those in most developed countries.

• Journal of Environmental Health Sciences
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• v.49 no.1
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• pp.37-47
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• 2023

Background: Paraben is a widely used substance with a preservative effect found in various materials such as food, medicine, personal care products, and cosmetics. Objectives: This study was conducted to identify the level of urinary paraben concentrations (i.e., methyl-, ethyl-, and propyl-) among Korean adults and to explore the factors related with the exposure levels. Methods: We analyzed the third period (2015~2017) of the Korean National Environmental Health Survey (KoNEHS). R statistical software (version 4.1.1) was used to estimate representative values for the whole population with weight variables to reflect sampling design. Whether urinary concentrations tended to increase as the level of paraben exposure-related characteristics increased was tested and P_trend was calculated using general linear models. Results: Urinary concentrations of all three parabens (i.e., methyl-, ethyl- and propyl-) were higher in women than in men (P_trend<0.0001, 0.008, and <0.0001), and the values of methylparaben and propylparaben tended to increase as the age of subjects increased (P_trend<0.0001, and <0.0001). Urinary concentrations of methylparaben and propylparaben were associated with intensity of exercise (P_trend<0.001, and 0.004), and that of propylparaben was higher in non-smokers (P_trend=0.01). In terms of paraben exposure-related variables, urinary concentrations of parabens (i.e., methyl-, ethyl- and propyl-) increased as the daily average frequency of teeth-brushing (P_trend<0.0001, 0.03 and 0.0001), the frequency of use of hair products (P_trend=0.005, 0.05 and 0.04), the frequency of use of makeup products (P_trend<0.001, 0.001 and <0.001), and the frequency of use of antibacterial products (P_trend=0.005, 0.02 and 0.02) increased. Conclusions: In our study, urinary concentrations of all three parabens are associated with gender, teethbrushing, hair products, make-up products, and antibacterial products. Methyl- and proyl-parabens were associated with age and intensity of exercise, and propyl-paraben was associated with smoking.

• Journal of the korean society of oceanography
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• v.32 no.4
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• pp.163-170
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• 1997

Some CMP gathers acquired from shallow marine seismic reflection survey in offshore Korea do not show the hyperbolic trend of moveout. It originated from so-called swell effect of source and streamer, which are towed under rough sea surface during the data acquisition. The observed time deviations of NMO-corrected traces can be entirely ascribed to the swell effect. To correct these time deviations, a residual statics is introduced using Genetic Algorithms (GA) into the swell correction. A new class of global optimization methods known as GA has recently been developed in the field of Artificial Intelligence and has a resemblance with the genetic evolution of biological systems. The basic idea in using GA as an optimization method is to represent a population of possible solutions or models in a chromosome-type encoding and manipulate these encoded models through simulated reproduction, crossover and mutation. GA parameters used in this paper are as follows: population size Q=40, probability of multiple-point crossover P$_c$=0.6, linear relationship of mutation probability P$_m$ from 0.002 to 0.004, and gray code representation are adopted. The number of the model participating in tournament selection (nt) is 3, and the number of expected copies desired for the best population member in the scaling of fitness is 1.5. With above parameters, an optimization run was iterated for 101 generations. The combination of above parameters are found to be optimal for the convergence of the algorithm. The resulting reflection events in every NMO-corrected CMP gather show good alignment and enhanced quality stack section.

• Nutrition Research and Practice
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• v.9 no.4
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• pp.404-410
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• 2015

BACKGROUND/OBJECTIVES: Although the association of body mass index (BMI) with metabolic syndrome (MetS) is well documented, there is little knowledge on the independent and joint associations of BMI and physical activity with MetS risk based on a continuous scoring system. This study was designed to explore the effect of physical activity on interactions between excess body weight and continuous metabolic syndrome (cMetS) in a nationwide survey of Iranian children and adolescents. SUBJECTS/METHODS: Data on 5,625 school students between 10 and 18 years of age were analyzed. BMI percentiles, screen time activity (STA), leisure time physical activity (LTPA) levels, and components of cMetS risk score were extracted. Standardized residuals (z-scores) were calculated for MetS components. Linear regression models were used to study the interactions between different combinations of cMetS, LTPA, and BMI percentiles. RESULTS: Overall, 984 (17.5%) subjects were underweight, whereas 501 (8.9%) and 451 (8%) participants were overweight and obese, respectively. All standardized values for cMetS components, except fasting blood glucose level, were directly correlated with BMI percentiles in all models (P-trend < 0.001); these associations were independent of STA and LTPA levels. Linear associations were also observed among LTPA and standardized residuals for blood pressure, high-density lipoprotein, and waist circumference (P-trend < 0.01). CONCLUSIONS: Our findings suggest that BMI percentiles are associated with cMetS risk score independent of LTPA and STA levels.

• Journal of the Korean association of regional geographers
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• v.3 no.1
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• pp.35-50
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• 1997

The purpose of this research seeks to analyze the spatial variations in the sex age structure which have been shown to exist within the study atrea, the Kyonggi province in Korea. In this study it is desired to use the Age Structure Index developed by Coulson in order to describe thi sex age structure of each of 186 tracts that comprise the tracted portion of the Kyonggi province. The mechanics of computing the Age Structure Index are found in the equation describing a linear least squares trend line: y=a+bx. For each census tract, the percentage of the population in each age group(y) was plotted against the middle age of each age group(x). The a is a constant representing the value of y, when x equals zero. The b is the regression coefficient and is a measure of the angle of the slope of the least squares trend line. Thus the value of b is the Age Structure Index for each census tract. The major results of this investigation can be summarized as follows: The spatial distributions of sex age structures in the Kyonggi province are far from random. They have exhibited great regularity with the yonger sex age structures near Seoul and a sharp decline to the older sex age structures out in all derections towards rural region. The results of this investigation should have important general significance for the study of the Kyonggi province Age Structure Index is a flexible, operational definition shich allows sex age structure to be measured, mapped, and incorporated in a wide variety of methods of statistical analysis. Futurer, it has been demonstrated that sex age structure varies spatially within Seoul metropolitan finge and that this variation is relagfed to many other attributes of the population. Especially, Age Structure Index is strongly related to the variables-rate of population growth rate. density, rate of numbers of manufacturing, land price. At the same time, considerably more research is needed before a genmeral body of knowlege concerning sex age structure can be developed.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.341-343
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• 2015

We present an analysis of the relation between star-formation (SF) and accretion luminosities of local type-2 active galactic nuclei (AGNs) at $0.01{\leq}z<0.22$. We match type-2 AGNs found in the Sloan Digital Sky Survey to current far-infrared (FIR) survey catalogues based on AKARI and Herschel. Estimating AGN luminosities from [$O{\small{III}}$]${\lambda}5007$ and [$O{\small{I}}$]${\lambda}6300$ emission lines, we find a positive linear trend between FIR and AGN luminosities over a wide dynamical range. This result appears to be inconsistent with recent reports that low-luminosity AGNs show no correlation between FIR and X-ray luminosities; this contradiction is likely due to Malmquist and sample selection biases. Moreover, we also find that pure-AGN candidates, for which the FIR radiation is thought to be AGN-dominated, show significant low-SF activities. These AGNs hosted by low-SF galaxies are rare in our sample. However, it is possible that the low fraction of low-SF AGN is caused by observational limitations, as recent FIR surveys are not sufficient to examine the population of high-luminosity AGNs hosted by low-SF galaxies.

• Archives of Plastic Surgery
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• v.35 no.5
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• pp.495-500
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• 2008

Purpose: Adequate tissue oxygenation is considered as an essential factor for wound healing. In the non-diabetic population, an uncompromised macrocirculation generally leads to adequate tissue oxygenation. On the contrary, the macrocirculation in diabetic patients may not correlate with tissue oxygenation because of structural changes in the capillary basement membrane. Nevertheless, many medical professionals in Korea rely on macrocirculation evaluation when predicting wound healing potential of the diabetic ulcers. The purpose of this study is to compare reliability of two common macrocirculation assessment methods, Doppler probing and CT angiography, on tissue oxygenation in diabetic foot patients. Methods: Doppler and CT angiography scores were given according to the patency of the anterior and posterior tibial arteries. Tissue oxygenation was measured by transcutaneous partial oxygen tension($TcpO_2$). Doppler and CT angiography scores were statistically analyzed against $TcpO_2$ values. Sixty-eight diabetic foot ulcer patients were included in this study. Results: The test was carried out on Doppler score and $TcpO_2$ variables displayed a p-value of 0.0202, and concluded that the two variables were statistically dependent. The test used to determine for linear trends between Doppler scores and $TcpO_2$ variables displayed a p-value of 0.0149, displaying statistical linear trend between the two variables. On the contrary, the tests between CT angiography scores and $TcpO_2$ variables showed p-values of 0.1242 and 0.6590, that means no correlation between CT angiography and $TcpO_2$ scores. Conclusion: Doppler probing is more reliable than CT angiography in predicting tissue oxygenation of diabetic foot ulcers.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.2
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• pp.94-104
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• 2015

Population and urban development along the coast is growing in South Korea, and particularly sea level rise is likely to increase the vulnerability of coastal areas. This study aims to investigate the sea level rise through Mann-Kendall(MK) test, ordinary linear regression(OR) and quantile regression analysis(QRA) with sea level data at the 20 tide stations along the coast of Korean Peninsula. First, statistically significant long-term trends were analysed using a non-parametric MK test and the test indicated statistically significant trends for 18 and 10 stations at the 5% significance level in the annual mean value of sea level and the annual maximum value of sea level, respectively. The QRA method showed better performance in terms of characterizing the degree of trend. QRA showed that an average annual rise in mean sea level is about 1-6 mm/year, and an average rise in maximum sea level is about 1-20 mm. It was found that upward convergent and upward divergent were a representative change given the nine-category distributional changes. We expect that in future work we will address nonstationarities with respect to sea level that were identified above, and develop a nonstationary frequency analysis with climate change scenarios.