• Journal of Korean Neurosurgical Society
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• v.65 no.1
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• pp.96-106
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• 2022

Objective : The most common complication of anterior cervical discectomy and fusion (ACDF) is cage subsidence and maintenance of disc height affects postoperative clinical outcomes. We considered cage subsidence as an inappropriate indicator for evaluating preservation of disc height. Thus, this study aimed to consider patients with complications such as reduced total disc height compared to that before surgery and evaluate the relevance of several factors before ACDF. Methods : We retrospectively reviewed the medical records of 40 patients who underwent stand-alone single-level ACDF using a polyetheretherketone (PEEK) cage at our institution between January 2012 and December 2018. Our study population comprised 19 male and 21 female patients aged 24-70 years. The minimum follow-up period was 1 year. Twenty-seven patients had preoperative bone mineral density (BMD) data on dual-energy X-ray absorptiometry. Clinical parameters included sex, age, body mass index, smoking history, and prior medical history. Radiologic parameters included the C2-7 cobb angle, segmental angle, sagittal vertical axis, disc height, and total intervertebral height (TIH) at the preoperative and postoperative periods. Cage decrement was defined as the reduction in TIH at the 6-month follow-up compared to preoperative TIH. To evaluate the bone quality, Hounsfield unit (HU) value was calculated in the axial and sagittal images of conventional computed tomography. Results : Lumbar BMD values and cervical HU values were significantly correlated (r=0.733, p<0.001). We divided the patients into two groups based on cage decrement, and 47.5% of the total patients were regarded as cage decrement. There were statistically significant differences in the parameters of measuring the HU value of the vertebra and intraoperative distraction between the two groups. Using these identified factors, we performed a receiver operating characteristic (ROC) curve analysis. Based on the ROC curve, the cut-off point was 530 at the HU value of the upper cortical and cancellous vertebrae (p=0.014; area under the curve [AUC], 0.727; sensitivity, 94.7%; specificity, 42.9%) and 22.41 at intraoperative distraction (p=0.017; AUC, 0.722; sensitivity, 85.7%; specificity, 57.9%). Using this value, we converted these parameters into a bifurcated variable and assessed the multinomial regression analysis to evaluate the risk factors for cage decrement in ACDF. Intraoperative distraction and HU value of the upper vertebral body were independent factors of postoperative subsidence. Conclusion : Insufficient intraoperative distraction and low HU value showed a strong relationship with postoperative intervertebral height reduction following single stand-alone PEEK cage ACDF.

• Korean Journal of Community Nutrition
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• v.27 no.3
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• pp.192-204
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• 2022

Objectives: This study examined the association between dietary behaviors and perceived health status among Korean adolescents from multicultural families. Methods: This cross-sectional study included 2,459 Korean adolescents from multicultural families (aged 13 ~ 18 years) who participated in the 2017 ~ 2019 Korea Youth Risk Behavior Surveys. Information on the sociodemographic variables, dietary behaviors, and lifestyle variables was self-reported using a web-based questionnaire. The dietary behaviors analyzed in this study were the breakfast and food intake frequencies, including fruit, vegetable, milk, fast food, carbonated drink, sweet drink, and high caffeine/energy drinks. The adolescents' health perception was self-rated as healthy, average, or unhealthy. The dietary behaviors associated with health perception were examined using a multiple logistic regression after adjusting for the confounding variables. Results: In this study population, 7.6% of adolescents perceived their health status as unhealthy, and 25.4% perceived it as average. The adolescents who were girls, middle school students, and in households with a low economic status showed significantly higher percentages of poor health perception (P-values < 0.001). Skipping breakfast was significantly associated with a negative health perception. Compared to the adolescents who consumed fruits every day, those who did not consume fruits during the previous week showed a higher odd ratio (OR) for a negative health perception [OR = 2.29, 95% confidence interval (CI) = 1.32-3.97]. The adolescents who frequently consumed carbonated drinks (≥ 5 times/week) perceived their health status as unhealthy relative to those who did not consume carbonated drinks (OR = 2.15, 95% CI = 1.25-3.71). Skipping breakfast was significantly associated with an increased OR for a negative health perception in girls but not in boys. Compared to adolescents with a normal weight, those with overweight/obesity (OR = 1.75, 95% CI = 1.21-2.52) and underweight (OR = 2.19, 95% CI = 1.25-3.82) showed higher ORs for negative health perception. Positive associations of overweight/obesity and underweight with negative health perception were observed in boys but not in girls. Conclusions: Dietary behaviors and weight status were associated with the health perception in Korean adolescents from multicultural families. These findings suggest that nutrition interventions on breakfast intake and healthy food choices for this population might effectively improve their weight and perceived health status.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.4
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• pp.493-499
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• 2022

The standards pertaining to the quality of discharged water in sewage treatment plants are strengthening, and accordingly, facilities in sewage treatment plants are being upgraded. In addition, the discharge water quality of sewage treatment plants must be maintained at a high level, and efficient sewage treatment plant operations have thus emerged as a very important issue. For the efficient operation of sewage treatment plants, this study applied a basic blowing amount calculation method based on sewage facilities to evaluate the required oxygen amount and blowing amount according to inflow water quality by logicizing various influencing factors. As a result of calculating the amount of air blown by applying actual April water quality data from sewage treatment plant A to the blower demand calculation developed through this study, it was found that the average amount of air blown was reduced by about 12%. When the blower demand calculation developed here is applied to an actual sewage treatment plant, the amount of air blown can be controlled based on the inflow water quality. This can facilitate the realization of an autonomous control of sewage treatment plants, in contrast to the existing sewage treatment operation method that relies on operational experience of operator. In addition, it is expected that efficient sewage treatment plants can be operated by reducing blowing amounts and power costs, which will contribute to both energy and carbon savings.

• Nutrition Research and Practice
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• v.16 no.1
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• pp.33-45
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• 2022

BACKGROUND/OBJECTIVES: Ginseng extract (GSE) and taurine (TR) are widely used antifatigue resources in functional foods. However, the mechanism underlying the antifatigue effects of GSE and TR are still unclear. Hence, we investigated whether GSE and TR have synergistic effects against fatigue in mice. MATERIALS/METHODS: L6 cells were treated with different concentrations of TR and GSE, and cell viability was determined using 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium. Oxidative stress was analyzed by immunocytochemistry using MitoTracker^TM Red FM and an anti-8-oxoguanine antibody. Respiratory gas analysis was performed to investigate metabolism. Expression of an activated protein kinase was analyzed using immunohistochemistry. Gene expression of cluster of differentiation 36 and pyruvate dehydrogenase lipoamide kinase isozyme 4 was measured using reverse transcription-polymerase chain reaction. Mice were orally administered TR, GSE, or their combination for 30 days, and then fatigue-related parameters, including lactate, blood urea nitrogen, and glycogen, were measured after forced swimming. RESULTS: TR and GSE reduced oxidative stress levels in hydrogen peroxide-stimulated L6 cells and enhanced the oxygen uptake and lipid metabolism in mice after acute exercise. After oral administration of TR or GSE for 30 days, the fatigue-related parameters did not change in mice. However, the mice administered GSE (400 mg/kg/day) alone for 30 days could swim longer than those from the other groups. Further, no synergistic effect was observed after the swimming exercise in mice treated with the TR and GSE combination for 30 days. CONCLUSIONS: Taken together, our data suggest that TR and GSE may exert antifatigue effects in mice after acute exercise by enhancing oxygen uptake and lipid oxidation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.226-234
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• 2021

The objective of this study is to establish the fundamental design data for axial load-displacement relationship under axial monotonic or cyclic responses of seismic damping·isolation (SDI) units developed for ceiling structures. The main parameters include the installation of a spring, the number of rubber layer, prestress stress of bolts for connector between the spring and rubbers, and loading type. Test results showed that SDI units with a spring in the core and higher prestress stress of bolts tended to be higher stiffness at the ascending branch and more ductile behavior at the descending branch. This trends more notable for the specimens under monotonic load rather than cyclic loads. Consequently, the energy dissipation of SDI unit can be optimally designed with the following conditions: installation of a spring within 3-layer rubbers and prestress applied to the bolts at 10% of their yielding strength . When compared with the experimental tension capacity of the developed SDI units, the predictions by JIS B 2704-1 and KDS 31 00 are conservative under monotonic loading but higher by approximately 10% under cyclic loading.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.2
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• pp.147-156
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• 2021

We report fluid inclusion study results of copper-bearing quartz veins in Zogdor area, which is located within the Gurvansayhan island arc terrane of Southern Mongolia. At the Zogdor area, structurecontrolled copper mineralization is hosted in granodiorite-porphyry, which emplaced in the late Cretaceous formation. Within this granodiorite porphyry, copper-bearing quartz veins are associated with the hydrothermal alteration that includes quartz-epidote-magnetite, and quartz-magnetite in the propylitic zones. The veins are classified into two types, according to their mineral composition, which occur mainly as chalcopyrite, rare amounts of bornite, magnetite, and pyrite. Fluid inclusions in the quartz veins from the quartz-magnetite±chalcopyrite and quartz-epidote-magnetite veins are two-phase aqueous inclusions having bubble sizes of 5-30 vol.%, evident salinities of 2.0-22.6 wt.% NaCl, and homogenization temperatures of 107-270℃. Based on mineral assemblages of the observed veins, along with the geochemical properties and alteration faces of the host rock, fluid inclusion data show that the study area corresponds to propylitic alteration zone in the porphyry Cu related mineralization.

• Korean Journal of Community Nutrition
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• v.26 no.6
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• pp.495-507
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• 2021

Objectives: This study examined regional differences in the intake of dietary total fat and saturated fatty acid (SFA) and their food sources among Korean adults. We also investigated the associations of SFA intake with metabolic diseases by region. Methods: This study included 13,926 adults (≥ 19y) who participated in the 2016 ~ 2019 Korea National Health and Nutrition Examination Surveys. The regions were divided into urban and rural areas according to the administrative districts where the participants lived. Using dietary data obtained from a 24-h recall, intake of total fat and SFA and their food sources were assessed by region. Metabolic diseases included obesity, abdominal obesity, and elevated total cholesterol and their association with SFA intake by region were examined using multiple logistic regression. Results: Of the participants, 19.6% lived in rural areas. In urban areas, the total fat and SFA intakes were higher than in rural areas: 21.2% of energy (%E) came from total fat and 6.9%E from SFA in urban areas, whereas 18.0%E came from total fat and 5.8%E from SFA in rural areas. The percentage of participants who exceeded the dietary reference intakes for total fat and SFA in urban areas was 16.5% and 41.9%, respectively, but 43.4% of participants in rural areas showed lower intake levels for total fat compared to the reference level. Young adults did not show regional differences in fat intake, and the percentage of subjects who exceeded the reference for SFA was high both in urban (58.5%) and rural (55.7%) areas. Among middle-aged and older adults, intake of fatty acids except for n-3 fatty acid was significantly higher in urban areas than in rural areas. About 69% of older adults in rural areas showed a lower intake of total fat compared to the reference level. The food sources for total fat and SFA were meat, soybean oil, eggs, and milk in both areas. The intake of fat from eggs, milk, mayonnaise, and bread was higher in urban areas, but the intake of fat from white rice and coffee mix was higher in rural areas. The SFA intake was positively associated with elevated serum total cholesterol in urban areas (4th quartile vs. 1st quartile, OR: 1.22, 95% CI: 1.06-1.40, P for trend: 0.043), but not in rural areas. Conclusions: Regional differences in total fat and SFA intakes and their food sources were observed among Korean adults. Our findings may help plan nutritional strategies to ameliorate regional health disparities.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.1
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• pp.77-100
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• 2022

In the era of low growth, many provincial cities are experiencing population decline and aging. Population decline phenomena such as reduction of productive manpower, reduction of finances, deterioration of quality of life, and collapse of the community base are occurring in a chain and are being pushed to the brink of extinction of the cities. This study aims to propose a methodology to objectively estimate the employment creation centers and setting the basic unit of industrial-centered zoning by applying spatial statistical techniques and GIS for the application of the compact city plan as an efficient spatial management policy in a city with a declining population. In details, based on reviewing previous studies on compact city, 'employment complex index(ECI)' were defined considering the number of workers, the number of settlers, and the area of development land, the employment creation center was estimated by applying the 'Local Moran's I' and 'Getis-Ord's Hot-Spot Analysis'. As a case study, changes in the four years of 2013, 2015, 2017, and 2019 were compared and analyzed for Changwon City. As a result, it was confirmed that the employment creation center is becoming compacted and polycentric, which is a significant result that reflects the actual situation well. This results provide the basic data for functional and institutional territorial governance for the regional revitalization platform, and provide meaningful information necessary for spatial policy decision-making, such as population reduction, regional gross domestic product, and public facility arrangement that can respond to energy savings, transportation plans, and medical and health plans.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.4
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• pp.63-80
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• 2022

As a technology to analyze and predict an issue has been developed by constructing real space into virtual space, it is becoming more important to acquire precise spatial information in complex cities. In this study, images were acquired using an unmanned aerial vehicle for urban area with complex landscapes, and land cover classification was performed object-based image analysis and semantic segmentation techniques, which were image classification technique suitable for high-resolution imagery. In addition, based on the imagery collected at the same time, the replicability of land cover classification of each artificial intelligence (AI) model was examined for areas that AI model did not learn. When the AI models are trained on the training site, the land cover classification accuracy is analyzed to be 89.3% for OBIA-RF, 85.0% for OBIA-DNN, and 95.3% for U-Net. When the AI models are applied to the replicability assessment site to evaluate replicability, the accuracy of OBIA-RF decreased by 7%, OBIA-DNN by 2.1% and U-Net by 2.3%. It is found that U-Net, which considers both morphological and spectroscopic characteristics, performs well in land cover classification accuracy and replicability evaluation. As precise spatial information becomes important, the results of this study are expected to contribute to urban environment research as a basic data generation method.

• Journal of the Korean Geotechnical Society
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• v.38 no.11
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• pp.107-118
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• 2022

The social need for stable hydrogen storage technologies that respond to the increasing demand for hydrogen energy is increasing. Among them, underground hydrogen storage is recognized as the most economical and reasonable storage method because of its vast hydrogen storage capacity. In Korea, low-depth hydrogen storage using artificial protective structures is being considered. Further, establishing corresponding safety standards and ground stability evaluation is becoming essential. This study evaluated the hydro-mechanical behavior of the ground during a hydrogen gas leak from a low-depth underground hydrogen storage facility through the HM coupled analysis model. The predictive reliability of the simulation model was verified through benchmark experiments. A parameter study was performed using a metamodel to analyze the sensitivity of factors affecting the surface uplift caused by the upward infiltration of high-pressure hydrogen gas. Accordingly, it was confirmed that the elastic modulus of the ground was the largest. The simulation results are considered to be valuable primary data for evaluating the complex analysis of hydrogen gas explosions as well as hydrogen gas leaks in the future.