• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.548-556
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• 2021

This study was conducted to investigate the applicability of lignocellulosic fiber and coconut shell activated carbon (CSA) for the production of a particulate matter (PM)-reducing air-filter as raw materials to solve the environmental problems of non-woven fabrics. CSA had a good potential to use as a raw material of air-filter for reducing volatile organic compounds as well as noxious metals, and reduction capability of the CSA was 5 times higher than that of wood fiber. Natural adhesives formulated with proteinaceous wastes mostly were applied successfully to fabricate air-filters with the shape of fiberboard. The air-filter fabricated with the minimum target density of 200 kg/m³ and the maximum CSA-content of 40 wt% in fiberboard had a good manageable strength. However, the fiberboard filters was required to make vent-holes for improving an air-permeability of the filters. Size of the CSA particles was adjusted to greater than 2 mesh with the consideration of strength and formability of the fiberboard. Three-layers fiberboard that only wood fiber and the mixture of wood fiber and CSA were formed in the surface and middle layers, respectively, was determined to the optimal condition for the production of air-filters. In addition, traditional Korean paper handmade from mulberry trees (TKP) showed a good PM-reducing property as an air-filter. It is concluded that air-filtering set composed of fiberboard with vent-holes and TKP instead of conventional air-filters made with non-woven fabrics can be used as a filter for reducing the concentrations of PM, VOC and noxious metals existed in indoor and outdoor spaces.

• Korean Journal of Food Science and Technology
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• v.53 no.4
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• pp.423-433
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• 2021

This study was performed to examine the neuroprotective effect of the ethyl acetate fraction from Eucommia ulmoides oliver leaf (EFEL) on PM_2.5-induced cytotoxicity. EFEL had higher total phenolic and flavonoid contents than the other fractions. In ABTS and DPPH radical scavenging activities, the IC₅₀ of EFEL was measured as 212.80 and 359.13 ㎍/mL, respectively. To investigate the neuroprotective effect of EFEL, MTT and DCF-DA assays were performed on HT22, MC-IXC, and BV-2 cells. EFEL effectively decreased PM_2.5-induced intercellular reactive oxygen species (ROS) content and inhibited PM_2.5-induced cell death. In the results of protein expression related to cellular cytotoxicity on microglial cells (BV-2), EFEL had an improvement effect on cell apoptosis and inflammatory pathways. Rutin and chlorogenic acid were identified as the main physiological compounds. Moreover, it was expected that EFEL, including rutin and chlorogenic acid, could be functional food substances with neuroprotective effects against PM_2.5-induced oxidative stress.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.223-229
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• 2021

To evaluate the protective effect of Codium fragile on fine dust (PM2.5)-induced cytotoxicity, we investigated its antioxidant activity and cell protective effect on PM2.5-exposed cells. The 40% ethanolic extract of C. fragile showed the highest total phenolic content, whereas the water extract of C. fragile showed the highest total polysaccharide content. The protective effect of the extracts on PM2.5-induced oxidative damage in nasal cavity (RPMI2650), lung (A549), brain (MC-IXC), hippocampus (HT-22), and microglia (BV-2) cells was evaluated by measuring the intracellular reactive oxygen species (ROS) content and cell viability. The results showed that the 40% ethanolic extract more efficiently inhibited ROS production than the water extract. In contrast, PM2.5-exposed cells treated with the water extract showed higher viability than those treated with the 40% ethanolic extract.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.449-460
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• 2021

The purpose of this study explained the experience of volunteering activities and the relationship of subjective self-awareness in order to examine the social meaning of volunteer activities. For adults aged 20 or older, 312 volunteering experience and social support awareness were analyzed on the level of self-identity by allocation sampling method depending on gender and age. The analysis results of this study were as follows. First, it was found that those who have experienced volunteer activitiies have a relatively simple willingness to participate in professional volunteer activities and those who have experienced volunteer activities. Second, social support and self-identification were different depending on whether they have experienced volunteer activities. Third, age, volunteer participation, willingness to participated in volunteering, and social support were analyzed as explanatory factors predicting self-identification of research participants. Based on the research results, volunteer activities to positively promote self-awareness suggested the need to practice volunteer activities according to the life cycle so that social meaning can be given. As a policy suggestion, the need for volunteer activities was closely analyzed to enable healthy self-forming for well-aging from adulthood to old age to discussed the need for policies and systems to strengthen volunteer motivation as leisure activities.

• Journal of Korea Water Resources Association
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• v.54 no.spc1
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• pp.1143-1154
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• 2021

The selection of activation function has a great influence on the groundwater level prediction performance of artificial neural network (ANN) model. In this study, five activation functions were applied to ANN model for two groundwater level observation wells in the middle mountainous area of the Pyoseon watershed in Jeju Island. The results of the prediction of the groundwater level were compared and analyzed, and the optimal activation function was derived. In addition, the results of LSTM model, which is a widely used recurrent neural network model, were compared and analyzed with the results of the ANN models with each activation function. As a result, ELU and Leaky ReLU functions were derived as the optimal activation functions for the prediction of the groundwater level for observation well with relatively large fluctuations in groundwater level and for observation well with relatively small fluctuations, respectively. On the other hand, sigmoid function had the lowest predictive performance among the five activation functions for training period, and produced inappropriate results in peak and lowest groundwater level prediction. The ANN-ELU and ANN-Leaky ReLU models showed groundwater level prediction performance comparable to that of the LSTM model, and thus had sufficient potential for application. The methods and results of this study can be usefully used in other studies.

• Journal of the Korean earth science society
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• v.42 no.3
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• pp.311-324
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• 2021

Recently, ten geosites have been considered in Hwaseong for endorsement as national geoparks, including the Jebudo, Gojeongri Dinosaur Egg Fossils, and Ueumdo geosites. The Jebudo geosite in the southern part of the Seoul metropolitan area has great potential for development as a new geoscience educational site because it has geological, geographical (landscape), and ecological significance. In this study, we described the geological characteristics through field surveys in the Jebudo geosite. We evaluated its potential as a geo-education site based on comparative analysis with other geosites in Hwaseong Geopark. In addition, we reviewed the practical effect of field education at geosites on the essential concepts and critical competence-oriented education emphasized in the current 2015 revised science curriculum. The Jebudo Geosite is geologically diverse, with various metamorphic rocks belonging to the Precambrian Seosan Group, such as quartzite, schist, and phyllite. Various geological structures, such as clastic dikes, faults, joints, foliation, and schistosity have also been recorded. Moreover, coastal geological features have been observed, including depositional landforms (gravel and sand beaches, dunes, and mudflats), sedimentary structures (ripples), erosional landforms (sea cliffs, sea caves, and sea stacks), and sea parting. The Jebudo geosite has considerable value as a new geo-education site with geological and geomorphological distinction from the Gojeongri Dinosaur Egg Fossils and Ueumdo geosites. The Jebudo geosite also has opportunities for geo-education and geo-tourism, such as mudflat experiences and infrastructures, such as coastal trails and viewing points. This geosite can help develop diverse geo-education programs that improve key competencies in the science curriculum, such as critical thinking, inquiry, and problem-solving. Furthermore, by conducting optimized geo-education focused on the characteristics of each geosite, the following can be established: (1) the expansion of learning space from school to geopark, (2) the improvement of understanding of specific content elements and linkage between essential concepts, and (3) the extension of the education scope throughout the earth system. There will be positive impacts on communication, participation, and lifelong learning skills through geopark education.

• Korean Journal of Breeding Science
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• v.42 no.6
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• pp.668-673
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• 2010

A new black seed coat soybean cultivar, 'Heugseong' was developed at the National Institute of Crop Science (NICS) in 2008. The goal to breed the black seed coat soybean is to develop the cultivar with large seed size, high yield, lodging tolerance, and resistance to disease such as soybean mosaic virus (SMV), and bacterial pustule. 'Heugseong' was selected from the cross between 'Gnome85', showing yellow seed coat, lodging tolerance, and high yield, and 'Cheongja', showing green cotyledon, and black seed coat. The preliminary, advanced and regional yield trials for this cultivar were carried out from 2004 to 2008. It has determinate growth habit, purple flower, brown pubescence, brown pod color, black seed coat, yellow cotyledon, elongated seed shape, oval leaf shape and large seed size (29.2 grams per 100 seeds). It was 4 days later in maturity than the check cultivar 'Ilpumgeomjeongkong'. 'Heugseong' was better than the check cultivar in the seed quality of isoflavone contents(1,913 ${\mu}g/g$). It has good adaptability for cooking with rice in ratio of water absorption and seed hardness, for physics of black tofu, and for fermented black soybean paste. The average yield of 'Heugseong' was 2.37 ton per hectare in the regional yield trials carried out in six locations of Korea from 2006 to 2008.

• Journal of Nutrition and Health
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• v.52 no.2
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• pp.227-241
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• 2019

Purpose: This study examined the relationship between caffeine intake and metabolic syndrome in Korean adults using the 2013 ~ 2016 Korea National Health and Nutrition Examination Survey data (KNHANES). Methods: The caffeine database (DB) developed by Food and Drug Safety Assessment Agency in 2014 was used to estimate the caffeine consumption. The food and beverage consumption of the 24 hr recall data of 2013 ~ 2016 KNHANES were matched to items in the caffeine DB and the daily caffeine intakes of the individuals were calculated. The sample was limited to non-pregnant healthy adults aged 19 years and older, who were not taking any medication for disease treatment. Results: The average daily caffeine intake was 41.97 mg, and the daily intake of caffeine of 97% of the participants was from coffee, teas, soft drinks, and other beverages. Multivariate analysis showed that the caffeine intake did not affect metabolic syndrome, hypertension, low HDL-cholesterol, and abdominal obesity. Diabetes and hypertriglyceridemia, however, were 0.76 (95% CI: 0.63 ~ 0.93), and 0.87 (95% CI: 0.77 ~ 0.98) in third quintile (Q3), and 0.66 (95% CI: 0.53 ~ 0.82) and 0.83 (95% CI: 0.73 ~ 0.94) in fourth quintile (Q4) compared to Q1, respectively. Therefore, caffeine intake of 3.66 ~ 45.81 mg per day is related to a lower risk of diabetes and hypertriglyceridemia. Conclusion: The study showed that adequate caffeine intake (approximately 45 mg) was associated with a lower prevalence of diabetes and hypertriglyceridemia. Therefore, it can be used as a guideline for the adequate level of caffeine intake for maintaining health.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.2
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• pp.105-113
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• 2019

A two-year study was conducted from 2017 to 2018 by the establishment of a test field at Chungju-si and Cheongyang-gun. Plant height, number of leaves, insects and diseases, and fresh and dry matter yields for corn hybrid('Kwangpyeongok') were investigated. Daily average, maximum, and minimum temperature, monthly average temperature, daily precipitation, and sunshine duration during the growing season were investigated. We selected climate-critical factors to corn productivity and conducted an evaluation of vulnerability to climate change from 1999 to 2018 for both regions. In 2018, the dry matter yield of forage corn was 6,475 and 7,511 kg/ha in Chungju and Cheongyang, respectively, which was half of that in 2017. The high temperature and drought phenomenon in the 2018 summer caused the corn yield to be low. As well as temperature, precipitation is an important climatic factor in corn production. As a result of climate impact vulnerability assessment, the vulnerability has increased recently compared to the past. It is anticipated that if the high temperature phenomenon and drought caused by climate change continues, a damage in corn production will occur.

• Journal of Climate Change Research
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• v.2 no.4
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• pp.317-331
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• 2011

The CERES-Barley crop simulation model of DSSAT package was used to assess the impacts of climate change on potential yield of winter covered barley in Korea. 56 sites over the southern part of Korean peninsula were selected to compare the climate change impacts in various climatic conditions. The climatological normals (1971~2000) and the three future climatological normals (2011~2040, 2041~2070, and 2071~2100), based on A1B climate change scenarios of Korea, were used in this study, and the three future climatological normals were simulated under three environmental conditions, where only temperature change, only carbon dioxide change, and both of temperature and carbon dioxide change with future A1B climate change scenarios, respectively. Results: The CERES-Barley model was suitable for predicting climate change impacts on the potential yield of winter covered barley, because of the agreement between observed and simulated outcomes (e.g., the coefficient of determination of grain yield equals 0.84). (1) The only increased temperature effect with the climate change scenarios was mostly negative to the potential yield of winter covered barley and its magnitude ranges from -21% to +1% for the three future normals. (2) The effect of the only elevated carbon dioxide on the potential yield of winter covered barley was positive and its magnitude ranged from 12% to 43% for the three future normals. (3) For increased temperature and elevated carbon dioxide change cases, potential yields increased by 13%, 21%, 19% increase for the 2011~2040, 2041~2070, 2071~2100 normals, respectively.