• Journal of Preventive Medicine and Public Health
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• v.24 no.1 s.33
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• pp.57-69
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• 1991

This study examined the cross-sectional association of central body fat distribution with hypertension as well as the superiority of medial calf skinfold measured as peripheral fat distribution over the conventional triceps skinfold using 450 Korean Navy divers selected by authors' convenience in 1990. Their mean age was 27.9 and range of it was 19-51. The centrally located body fat was approximated by subscapular skinfold and peripherally located fat by triceps and medial calf skinfolds. Four indices were constructed from these skinfold measures to reflect central versus peripheral fat distribution pattern : 2 ratios and 2 differences. After controlling age and overall obesity (body mass index), prevalance odds ratios of the 2/4, 3/4, 4/4 quartiles of subscapular skinfold comparing with lowest 1/4 quartile were 2.05(95% confidence interval, CI 1.18-3.59), 2.02(95% CI 1.06-3.86), 4.00 (95% CI 1.99-8.06) respectively. The difference of subscapular and medial calf skinfolds was associated with hypertension (odds ratio 2.45, 95% CI 1.28-4.68 comparing highest with lowest quartiles). Triceps and medial calf skinfolds alone did not show any odds ratio not including unity. The adjusted odds ratios were generally reduced in small magnitude compared with crude odds ratios not adjusted for age and overall obesity. The medial calf skinfold appeared to be more representative of peripheral body fat distribution than triceps skinfold. These findings suggest that central fat distribution rather than peripheral distribution is associated with hypertension independent of age and overall level of obesity and medial calf skinfold may replace conventional triceps skinfold in predicting peripheral distribution of body fat.

• Journal of Preventive Medicine and Public Health
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• v.38 no.1
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• pp.101-106
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• 2005

Objectives : We conducted this study to examine the association between serum GGT levels within the normal range and the risk factors of cardiovascular diseases Methods : We examined the cross-sectional association between serum GGT and the systolic and diastolic blood pressure, fasting blood glucose, total cholesterol, triglyceride, high density lipoprotein cholesterol (HDLcholesterol), and uric acid among 975 subjects that participated in the health examination of a university hospital located in Daegu city. All the patients' GGT levels were within the normal range. Results : After adjustment were made for age, body mass index (BMI), smoking status, drinking frequency, exercise frequency and coffee intake, the serum GGT level was positively associated with fasting blood glucose (p<0.01), total cholesterol (p<0.01), and triglyceride (p<0.01) in men, and it was positively associated with fasting blood glucose (p<0.01), total cholesterol (p<0.05), triglyceride (p<0.01), and uric acid (p<0.01) in women. The associations were not significantly different depending on the status of alcohol drinking or obesity, except for the associations of serum GGT with diastolic blood pressure (P for interaction=0.04) and uric acid (P for interaction=0.04) between the lean and obese subjects. Conclusions : Serum GGT levels within the normal range were positively associated with fasting blood glucose, triglyceride and uric acid in most subgroups irrespective of the drinking or obesity status. These results suggest that GGT has important clinical implications as being more than just a marker of alcohol consumption and hepatobiliary disease.

• Journal of Preventive Medicine and Public Health
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• v.27 no.2 s.46
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• pp.274-285
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• 1994

The effects of resin on the respiratory health have been investigated in 309 workers from four iron and steel foundries and the results compared with those from 122 workers who were not significantly exposed to resin gas and silica dust at the same industries. Phenol-formaldehyde resin was used in the core making and molding processes and workers were exposed to their decomposition products as well as to silica dust containing particulates. The subjects were grouped according to formaldehyde, dust and other gas exposures, and smoking habits were considered also in thi analysis. Standardized respiratory symptom questionnaire was administered by trained interviewers. Chest radiograph, pulmonary funtion tests, and methacholine challenge tests were done. Environmental measurements at the breathing zone were carried out to determine levels of formaldehyde, respiable dust and total dust. Foundry workers had a higher prevalence of symptoms of chronic bronchitis with chronic phlegm and chronic cough when exposed to dust. Exposure to gas was significantly associated with lowered $FEV_1$ and obstructive pulmonary function changes. Exposure to formaldehyde and phenol gas was associated with wheezing symptom among workers, but $FEV_1$ changes after methacholine challenge were not significantly different among different exposure groups. When asthma was defined as the presence of bronchial hyperreactivity with more than 20% decrease in $FEV_1$ after methacholine challenge, 17 workers out of 222 tested had asthma. Fewer asthmatic welters were found among groups exposed to formaldehyde, gas and dust, which indicates a healthy worker effects ill a cross-sectional study. The concentration of formaldehyde gas ranged from 0.24 to 0.43 ppm among studied foundries. The authors conclude that formaldehyde and phenol gas from combusted resin is probably the cause of asthmatic symptoms and also a selection force of those with higher bronchial reactivity away from exposures.

• Toxicological Research
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• v.32 no.1
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• pp.57-64
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• 2016

Recently several studies reported that the renal toxicity of lead (Pb) and cadmium (Cd) may exist in even a low level exposure. In terms of the deterioration of tubular function, it affects the loss of divalent metals and leads to other complications, so renal tubular effect of heavy metals should be well managed. Considering the exposure to heavy metals in reality, it is hard to find the case that human is exposed to only one heavy metal. We designed a cross-sectional study using Korean Research Project on the Integrated Exposure Assessment (KRIEFS) data to investigate the renal effects of multiple metal exposure in general population. We used blood Pb and urinary Cd as exposure measures, and urinary N-acetyl-${\beta}$-D-glucosaminidase (NAG) and ${\beta}_2$-microglobulin (${\beta}_2$-MG) as renal tubular impairment outcome. We conducted linear regression to identify the association between each heavy metal and urinary NAG and ${\beta}_2$-MG. And then, we conducted linear regression including the interaction term. Of 1953 adults in KRIEFS (2010~2011), the geometric mean of blood Pb and urinary Cd concentration was $2.21{\mu}g/dL$ (geometric $SD=1.49{\mu}g/dL$) and $1.08{\mu}g/g\;cr$ (geometric $SD=1.98{\mu}g/g\;cr$), respectively. In urinary Cd, the strength of the association was also high after adjusting (urinary NAG: ${\beta}=0.44$, p < 0.001; urinary ${\beta}_2$-MG: ${\beta}=0.13$, p = 0.002). Finally, we identified the positive interactions for the two renal biomarkers. The interaction effect of the two heavy metals of ${\beta}_2$-MG was greater than that of NAG. It is very important in public health perspective if the low level exposure to multiple heavy metals has an interaction effect on kidney. More epidemiological studies for the interaction and toxicological studies on the mechanism are needed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.2
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• pp.211-219
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• 2015

Objectives: We aimed to examine the association between experience of workplace violence and musculoskeletal pain among wage workers in South Korea. Methods: We analyzed a cross-sectional survey of 29,601 wage workers from the third wave Korean Working Conditions Survey in 2011. Experience of workplace violence was assessed through three questions, "Over the past 12 months, have you ever experienced: (1) physical violence, (2) bullying, or (3) sexual harassment at workplace?" Musculoskeletal pain was measured using the three questions, "Over the past 12 months, have you ever experienced: (1) low back pain, or (2) upper limb pain(i.e. shoulder, neck, and arm), or (3) lower limb pain(i.e. hip, leg, knee, and foot)?" Wage workers could answer 'Yes' or 'No' to each of the three questions. Multivariate negative binomial regression was applied to examine the association between workplace violence and musculoskeletal pain after adjusting for confounders including self-reported physical work factors. All analyses were performed using STATA/SE version 13.0. Results: Physical violence was associated with low back pain(PR: 2.16, 95% CI: 1.77, 2.65), upper(PR: 1.65, 95% CI: 1.45, 1.88) and lower limb pain(PR: 1.81, 95% CI: 1.52, 2.15) among male wage workers whereas it was related to upper(PR: 1.86, 95% CI: 1.53, 2.26) and lower limb pain(PR: 2.95, 95% CI: 2.47, 3.53) among female wage workers. Significant association was observed between sexual harassment and upper(PR: 1.25, 95% CI: 1.01, 1.56) and lower limb pain(PR: 2.41, 95% CI: 1.97, 2.93) among female wage workers whereas the association was only significant in the analysis with lower limb pain(PR: 1.87, 95% CI: 1.17, 2.97) among male wage workers. Bullying was associated only with lower limb pains among both male(PR: 1.77, 95% CI: 1.32, 2.37) and female(PR: 2.10, 95% CI: 1.69, 2.61) wage workers. Conclusions: This study found that experience of workplace violence, particularly physical violence and sexual harassment, was associated with musculoskeletal pain among Korean wage workers.

• Journal of Wetlands Research
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• v.18 no.3
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• pp.324-329
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• 2016

Constructed wetlands are widely applied in urban and rural areas for various purposes such as pollutants reduction, acquisition of eco-spaces and habitats, flooding reduction, acquisition of water resources and environmental education. Since the design of constructed wetlands utilizes ecosystems, special consideration must be given to ecological mechanisms, environmental mechanisms and hydrological mechanisms. To ensure the sustainable functionality of constructed wetlands, it is necessary to achieve stable flow rate and velocity, and remove sediments to ensure sufficient space for detention. To enhance the efficiency of constructed wetland sedimentation basins, this study determined the optimal position for baffle installation, and applied Computational Fluid Dynamics (CFD) to the cross-sectional design of wetlands. CFD analysis revealed that the decrease in flow velocity with baffle installation enhanced the efficiency of sedimentation of particulate matters. Vertical baffles had higher sedimentation efficiency than those with an inclined angle. When vertical baffles were installed in the sedimentation basin of a hybrid constructed wetland to reduce non-point source pollutants in urban areas, the average flow velocity within the basin decreased by 10~30%, while the sedimentation efficiency improved by 1.3~1.5 times. The application of CFD to constructed wetlands is expected to improve the cost efficiency of designing hybrid constructed wetlands with high removal efficiency.

• Korean Journal of Materials Research
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• v.6 no.7
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• pp.733-741
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• 1996

In this study MeV Si self ion implantations were done to reveal the intrinsic behavior of defect formation by excluding the possibility of chemical interactions between substrate atoms and dopant ones. Self implantations were conducted using Tandem Accelerator with energy ranges from 1 to 3 MeV. Defect formation by high energy ion implantation has a significant characteristics in that the lattice damage is concentrated near Rp and isolated from the surface. In order to investigate the energy dependence on defect formation, implantation energies were varied from 1 to 3 MeV under a constant dose of $1{\times}10^{15}/cm^2$. RBS channe!ed spectra showed that the depth at which as-implanted damaged layer formed increases as energy increases and that near surface region maintains better crystallinity as energy increases. Cross sectional TEM results agree well with RBS ones. In a TEM image as-implanted damaged layer appears as a dark band, where secondary defects are formed upon annealing. In the case of 2 MeV $Si^+$ self implantation a critical dose for the secondary defect formation was found to be between $3{\times}10^{14}/cm^24$ and $5{\times}10^{14}/cm^2$. Upon annealing the upper layer of the dark band was removed while the bottom part of the dark band did not move. The observed defect behavior by TEM was interpreted by Monte Carlo computer simulations using TRIM-code. SIMS analyses indicated that the secondary defect formed after annealing gettered oxygen impurities existed in silicon.

• Journal of Conservation Science
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• v.36 no.5
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• pp.383-392
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• 2020

This study aimed to examine the characteristics of paint used for modern art works by conducting sectional observations, inorganic component analysis, and infrared spectroscopic analysis on the painted layers of 3 painted sculpture works exhibited in the Yongdam Dam Environmental Sculpture Park and Naejangsan Sculpture Park in the Jeollabuk-do area. The observations indicate that the cross section is composed of various layers of 2-3 folds, the thickness of the layers was uneven at approximately 23-150 ㎛, and putty was used for plate treatment prior to painting. Inorganic component analysis results show that putty containing calcium carbonate, iron oxide, diatomite, and titanium dioxide was used for the putty layer. It is also assumed that paint mixed with green (Cr₂O₃), blue(sodaliteblue), red(chromered), andwhite(TiO₂) colors were used for the painted layers. As a result of infrared spectroscopic analysis to confirm the types of paint, it is estimated that the paint was mixed with polyester resin and an extender.

• Health Policy and Management
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• v.18 no.3
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• pp.18-40
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• 2008

Measurements of health related quality of life can be used to compare patients with specific conditions to average individuals in the general population in a similar age and gender group. However there are few data available regarding health related quality of life for the general population of Korea. Therefore, this study was conducted to examine the validity of the Korean version of EQ-5D and to measure the health related quality of life of the general adult population in a metropolitan city. The survey was cross-sectional and employed a stratified and multistage sampling design through 100 examination sites in 5 districts of UIsan. A total of 12,644 individuals from 4,112 households participated in the survey. Of these, we analyzed data from 8,068 adults who were over 19 years old and completed the EQ-5D. To examine the validity of the questionnaire, the differences in 5 dimensions and the $EQ-5D_{index}$ were analyzed with regard to demographic and socioeconomic factors such as sex, age, income, and education. In addition, visual analogue scales (VAS) were used to evaluate the overall health related quality of life issues of the respondents. The level of health related quality of life of the general adult population was then compared with the results from the third Korean National Health and Nutrition Examination Survey and other countries. There were a small number of people with problems related tomobility, self-care, and usual activity. In addition, many people complained ofpain/discomfort and anxiety/depression. The complaint rate in each dimension, VAS, and $EQ-5D_{index}$ indicated relatively better states for males, the younger group, the higher income group, and the higher education group. In addition, the level of health related quality of life of the general population of Ulsan was relatively higher than that of Koreans nationwide as well as the populations of other countries. EQ-SD provided a valid measure of the health-related quality of life of the general adult population. In addition, the results of a survey of Ulsan revealed that the quality of life of its population is better than that of the overall population of Korea and of the populations of other countries.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.228-243
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• 1997

The changes of microstructures, morphology of sclerotic dentin and bonding aspects generated by an adhesive resin was investigated. Incisors and premolars showing natural cervical abrasions were collected and conditioned with 10 % phosphoric acid or 10 % maleic acid. The sclerotic dentin specimens were then rinsed and blot-dried and applied with dentin adhesive (All Bond 2) to the conditioned dentin surface. To examine the morphologic change of the sclerotic dentin specimen after etching and bonding procedure, the treated specimens were examined by SEM. To analyze the chemical composition of sclerotic dentin and crystals occluding dentinal tubules, the sclerotic dentin specimen was powdered and examined with X-ray Diffractometer. To investigate the Ca/P weight percent ratio within the dentinal tubules, the sclerotic dentin specimen was fractured perpendicularly to the long axis of the tooth from the center of cervical abrasion lesion and then examined with EDX(Energy Dispersive X-ray) microanalyzer. The results were as follows : 1. The increased width of peritubular dentin and the depositions of the irregular amorphous materials within the dentinal tubules were showed in the sclerotic dentin specimens. 2. After the treatment of sclerotic dentin specimen with 10 % phosphoric acid or 10 % maleic acid, the lateral side of tubules rather than cross-sectional tubule openings was showed exclusively at the incisal and gingival incline of the specimens. 3. After the treatment of sclerotic dentin specimen with 10 % phosphoric acid or 10 % maleic acid, the hybrid layer was not formed evidently and the resin tag was not formed or shortly penetrated into the tubules with the thinner diameter. 4. According to the results of XRD analysis of the sclerotic dentin specimen, Hydroxyapatite and Octacalcium phosphate were predominent, however, Whitlockite crystals were rare. 5. The mean Ca/P weight percent ratio analysed from 5 fractured sclerotic dentin specimens was $2.322{\pm}0.170$ at the intertubular dentin, $1.826{\pm}0.051$ within the dentinal tubule.