• Korean Chemical Engineering Research
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• v.57 no.5
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• pp.687-694
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• 2019

In order to investigate the behavior of limestones which have been usually used for in-situ desulfurization reaction in circulating fluidized bed combustors, the attrition characteristics and calcination reactions of domestic limestones were analyzed in this study by using a thermogravimetric analyzer and an ASTM D5757-95 attrition tester. The average size distribution of limestones in circulating fluidized bed boilers have to be changed due to the attrition of particle-particle and particle-reactor wall and the calcination reaction. Domestic limestones might be used in commercial circulating fluidized bed boilers, but the attrition behaviors and particle size changes of limestones were varied. In calcination experiments at $850^{\circ}C$, the calcination reaction were varied with limestone samples. The calcination reaction time increased with an increase of particle size. Also, fine particles generated the attrition test of calcined limestone was 20% higher than those generated the attrition test of original limestone.

• Korean Journal of Environmental Agriculture
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• v.38 no.1
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• pp.61-67
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• 2019

BACKGROUND: Many studies on artificial lighting have been recently performed to investigate its effect on agricultural products with good quality. This review was aimed at comparing the effects of artificial light on functional metabolites of the plants that were grown in greenhouses and growth chamber. METHODS AND RESULTS: It has been summarized that artificial lighting both in growth chambers and greenhouses caused different functional metabolites patterns depending on light quality. Even though the same light quality was applied, different patterns in metabolites were observed in different plant species. For the same species, supplementation of the same light quality in both growth chambers and greenhouses did cause different functional metabolites patterns. CONCLUSION: Artificial lighting caused different patterns in functional metabolites of plants grown in greenhouses and growth chambers, depending on the light quality and/or plant species. The manipulation of plant growth and functional metabolites would be possible by engineering the light qualities, but knowledge on proper lighting condition depending on plant species and growth places would be necessary.

• Journal of the Korean Society of Earth Science Education
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• v.11 no.3
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• pp.158-171
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• 2018

The purpose of this research was to examine the attitudes toward science on geology and satisfaction of education according to the stage of cognitive development of middle school students mainly on the geoscience education program of IS-GEO(International School for Geoscience and Mineral Resources) which is the KIGAM(Korea Institute of Geoscience and Mineral Resources) and to see what kind of correlation it shows between these. The subjects of research are 139 out of 282 students who participated in the geoscience education program conducted at the IS-GEO which is a KIGAM in 2018 by random sampling. Therefore, the research results are as follows. First, the concrete operational stage was 44%, the transition stage was 32%, the formal operational stage was 24%, 76% of the middle school student's cognitive development level didn't reach at the formal operational stage. Also, attitudes towards science on geology indicated statistically significant differences in the sub-region in "Geology-related science class", "Suburban geological science class", "Recognition of geological science and technology". Second, there was no statistically significant difference in educational satisfaction depending on the stages of every cognitive development. In other words, all participants at the cognitive stages showed high satisfaction with the geological education program which progresses at the IS-GEO, which is the KIGAM. Third, the correlation between educational satisfaction and attitudes toward science on geology showed a statistically meaningful static correlation. Therefore, attitudes toward science on geology can be positively displayed that participants who participated in geoscience education program and training of the IS-GEO have high satisfaction of education in science behavioral system.

• Applied Chemistry for Engineering
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• v.30 no.2
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• pp.160-166
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• 2019

In this study, oxygen functional groups were introduced on activated carbon fibers (ACFs) by oxygen plasma treatment to improve the adsorption performance on an acetic acid which is a sick house syndrome induced gas. The active species was generated more as the flow rate of the oxygen gas increased during the plasma treatment. For this reason, the specific surface area (SSA) of the ACFs decreased with much more physical and chemical etching. In particular, the SSA of the sample (A-O60) injected with an oxygen gas flow rate of 60 sccm was reduced to about $1.198m^2/g$, which was about 6.95% lower than that of the untreated samples. On the other hand, the oxygen content introduced into the surface of ACFs increased up to 35.87%. Also, the adsorption performance on the acetic acid gas of the oxygen plasma-treated ACFs was improved by up to 43% compared to that of using the untreated ACFs. It is attributed to the formation of the hydrogen bonding due to the dipole moments between acetic acid molecules and oxygen functional groups such as O=C-O introduced by the oxygen plasma treatment.

• Therapeutic Science for Rehabilitation
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• v.8 no.2
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• pp.43-53
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• 2019

Objective : This study aimed to identify the characteristics of hand function according to age and sex in older adults. Methods : This study included 103 healthy adults aged ${\geq}60$ years. The Korean version of TEMPA was used to assess hand function and a Jamar dynamometer and pinch gauge were used to assess hand and pinch strength in all participants. Results : The results of hand function assessment showed that speed of task execution (mean = 121.32 s, SD = 18.07 s in subjects aged 60-69; mean = 144.97 s, SD = 28.43 s in subjects aged 70-79; and mean = 160.93 s, SD = 38.33 s in subjects aged ${\geq}80$, p < .001) and fine movement (mean score = -.14, SD = .40 in subjects aged 60-69; mean score = -.63, SD = 1.07 in subjects aged 70-79; and mean score = -.57, SD = .65 in subjects aged ${\geq}80$, p = .01) decreased significantly with age. The male group showed better speed of task execution (mean = 133.54, SD = 22.83 in males vs. mean = 150.55, SD = 39.89 in females, p < .01) and fine movement (mean score = -.16, SD = .37 in males vs. mean score = -.46, SD = .58 in females, p < .01) than the female group. Hand strength also decreased significantly with age (p < .05, to p < .001). Conclusion : Occupational therapists should be aware of the decline in hand function (especially speed of task execution and fine movement) and strength in older adults, as well as the need to provide interventions to treat this decline.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.3
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• pp.202-212
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• 2021

Objectives: The reproductive health of female workers has been extensively investigated in South Korea and other countries worldwide. However, few studies have discussed the reproductive health of male workers. In this study, we reviewed the recent literature that reports on the effects of occupational exposure on the reproductive health of male workers and the health of their children. Methods: In May 2020 we used the PubMed search engine to search the literature over the last 10 years and chose case-control, cohort, and cross-sectional studies and reviews. We selected epidemiological studies that investigated the association between pre-pregnant occupational exposure and the reproductive health of male workers and the health of their children. We excluded case reports, non-epidemiological studies (animal experiments, cellular-level experiments, and similar articles), and studies that described postnatal occupational exposure. Results: We eventually selected 23 studies. The studies that included exclusively male workers reported that those employed in the agricultural sector or those exposed to pesticides showed lower blood levels of reproductive hormones and a high risk of lympho-hematopoietic system cancer in their children. Male workers exposed to complex organic solvents and organic compounds showed a high risk of poor semen quality, increased time to pregnancy, decreased blood levels of reproductive hormones, and a high risk of lympho-hematopoietic system cancer in their children. Male workers employed in occupations that involved significant social contact, or in the leather and livestock industries, and in occupations with high levels of exposure to lead and organic solvents showed a high risk of malignancies, including lympho-hematopoietic system cancer, neuroblastoma, and central nervous system tumors in their children. Studies that investigated both male and female workers reported that children of male smelters showed a high risk of premature birth, and children of male workers exposed to metals showed a high risk of hypospadias and cryptorchidism. Children of male welders and workers employed in the glass, ceramic, and tile industries showed a high risk of premature birth. Conclusion: The findings of this study will serve as basic data for further research on male workers' reproductive health and provide a scientific basis for the development of strategies to protect the reproductive health of males employed in high-risk occupations. Moreover, the results of this study may provide guidelines to improve the understanding of and knowledge on male workers' reproductive health.

• Korean Journal of Construction Engineering and Management
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• v.22 no.5
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• pp.73-85
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• 2021

This study proposes an efficient management direction for Korean construction accident cases through a deep learning-based text data classification model. A deep learning model was developed, which categorizes five categories of construction accidents: fall, electric shock, flying object, collapse, and narrowness, which are representative accident types of KOSHA. After initial model tests, the classification accuracy of fall disasters was relatively high, while other types were classified as fall disasters. Through these results, it was analyzed that 1) specific accident-causing behavior, 2) similar sentence structure, and 3) complex accidents corresponding to multiple types affect the results. Two accuracy improvement experiments were then conducted: 1) reclassification, 2) elimination. As a result, the classification performance improved with 185.7% when eliminating complex accidents. Through this, the multicollinearity of complex accidents, including the contents of multiple accident types, was resolved. In conclusion, this study suggests the necessity to independently manage complex accidents while preparing a system to describe the situation of future accidents in detail.

• Investigative Magnetic Resonance Imaging
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• v.25 no.3
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• pp.164-171
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• 2021

Purpose: Mild cognitive impairment (MCI) is a prodromal stage of Alzheimer's disease (AD). Brain atrophy in this disease spectrum begins in the medial temporal lobe structure, which can be recognized by magnetic resonance imaging. To overcome the unsatisfactory inter-observer reliability of visual evaluation, quantitative brain volumetry has been developed and widely investigated for the diagnosis of MCI and AD. The aim of this study was to assess the prediction accuracy of quantitative brain volumetry using a fully automated segmentation software package, NeuroQuant^®, for the diagnosis of MCI. Materials and Methods: A total of 418 subjects from the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer's Disease cohort were included in our study. Each participant was allocated to either a cognitively normal old group (n = 285) or an MCI group (n = 133). Brain volumetric data were obtained from T1-weighted images using the NeuroQuant software package. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed to investigate relevant brain regions and their prediction accuracies. Results: Multivariate logistic regression analysis revealed that normative percentiles of the hippocampus (P < 0.001), amygdala (P = 0.003), frontal lobe (P = 0.049), medial parietal lobe (P = 0.023), and third ventricle (P = 0.012) were independent predictive factors for MCI. In ROC analysis, normative percentiles of the hippocampus and amygdala showed fair accuracies in the diagnosis of MCI (area under the curve: 0.739 and 0.727, respectively). Conclusion: Normative percentiles of the hippocampus and amygdala provided by the fully automated segmentation software could be used for screening MCI with a reasonable post-processing time. This information might help us interpret structural MRI in patients with cognitive impairment.

• Journal of Digital Convergence
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• v.19 no.8
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• pp.235-240
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• 2021

Currently, the number of visitors to Oreum is increasing and the trend of tourism is changing rapidly. The motivation for visiting Oreum is also changing from relaxation and pleasure to experiences. In line with this change, people visit the mountain by selecting motivation such as marriage and family photos, not just exercise. However, it is difficult to search for an Oreum that matches the tourists' motivation. In order to solve these problems, we proposed a system that provides the association between Oreum and concept based on the number of search results from web search engines in real time. User can select the desired date to check the associations for past or selected periods and concepts. Through this research, visitors to Oreum, Jeju's natural heritage, can contribute to the development of tourism in Jeju. In the future, the concept of visiting beaches or seas, not just Jeju Oreum, can be provided. In this work, search results from websites are collected, stored in a database, and search results of Oreum and concept are provided on the homepage to classify Oreum trends.

• Journal of Yeungnam Medical Science
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• v.38 no.3
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• pp.208-218
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• 2021

Background: Hemophagocytic lymphohistiocytosis (HLH) is a rare but severe, life-threatening inflammatory condition if untreated. We aimed to investigate the etiologies, outcomes, and risk factors for death in children and adults with HLH. Methods: The medical records of patients who met the HLH criteria of two regional university hospitals in Korea between January 2001 and December 2019 were retrospectively investigated. Results: Sixty patients with HLH (35 children and 25 adults) were included. The median age at diagnosis was 7.0 years (range, 0.1-83 years), and the median follow-up duration was 8.5 months (range, 0-204 months). Four patients had primary HLH, 48 patients had secondary HLH (20 infection-associated, 18 neoplasm-associated, and 10 autoimmune-associated HLH), and eight patients had HLH of unknown cause. Infection was the most common cause in children (14/35, 40.0%), whereas neoplasia was the most common cause in adults (13/25, 52.0%). Twenty-eight patients were treated with HLH-2004/94 immunochemotherapy. The 5-year overall survival (OS) rate for all HLH patients was 59.9%. The 5-year OS rates for patients with primary, infection-associated, neoplasm-associated, autoimmune-associated, and unknown cause HLH were 25.0%, 85.0%, 26.7%, 87.5%, and 62.5%, respectively. Using multivariate analysis, neoplasm-induced HLH (p=0.001) and a platelet count <50×10⁹/L (p=0.008) were identified as independent risk factors for poor prognosis in patients with HLH. Conclusion: Infection was the most common cause of HLH in children, while it was neoplasia in adults. The 5-year OS rate for all HLH patients was 59.9%. HLH caused by an underlying neoplasm or a low platelet count at the time of diagnosis were risk factors for poor prognosis.