• Korean Journal of Materials Research
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• v.28 no.11
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• pp.640-645
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• 2018

The design of non-precious electrocatalysts with low-cost, good stability, and an improved oxygen reduction reaction(ORR) to replace the platinium-based electrocatalyst is significant for application of fuel cells and metal-air batteries with high energy density. In this study, we synthesize iron-carbide($Fe_3C$) embedded nitrogen(N) doped carbon nanofiber(CNF) as electrocatalysts for ORRs using electrospinning, precursor deposition, and carbonization. To optimize electrochemical performance, we study the three stages according to different amounts of iron precursor. Among them, $Fe_3C$-embedded N doped CNF-1 exhibits the most improved electrochemical performance with a high onset potential of -0.18 V, a high $E_{1/2}$ of -0.29 V, and a nearly four-electron pathway (n = 3.77). In addition, $Fe_3C$-embedded N doped CNF-1 displays exellent long-term stabillity with the lowest ${\Delta}E_{1/2}=8mV$ compared to the other electrocatalysts. The improved electrochemical properties are attributed to synergestic effect of N-doping and well-dispersed iron carbide embedded in CNF. Consequently, $Fe_3C$-embedded N doped CNF is a promising candidate for non-precious electrocatalysts for high-performance ORRs.

• Biomolecules & Therapeutics
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• v.29 no.4
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• pp.419-426
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• 2021

In this study, we aimed to investigate the effects of 8 weeks of treatment with a combination of evogliptin and leucine, a branched-chain amino acid, in mice with high-fat diet (HFD)-induced diabetes. Treatment with evogliptin alone or in combination with leucine reduced the body weight of the mice, compared to the case for those from the HFD control group. Long-term treatment with evogliptin alone or in combination with leucine resulted in a significant reduction in glucose intolerance; however, leucine alone did not affect postprandial glucose control, compared to the case for the mice from the HFD control group. Furthermore, the combination of evogliptin and leucine prevented HFD-induced insulin resistance, which was associated with improved homeostasis model assessment for insulin resistance, accompanied by markedly reduced liver fat deposition, hepatic triglyceride content, and plasma alanine aminotransferase levels. The combination of evogliptin and leucine increased the gene expression levels of hepatic peroxisome proliferator-activated receptor alpha, whereas those of the sterol regulatory element-binding protein 1 and stearoyl-CoA desaturase 1 were not altered, compared to the case in the HFD-fed mice (p<0.05). Thus, our results suggest that the combination of evogliptin and leucine may be beneficial for treating patients with type 2 diabetes and hepatic steatosis; however, further studies are needed to delineate the molecular mechanisms underlying the action of this combination.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.1
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• pp.43-47
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• 2022

In this study, we demonstrated an eco-friendly thin-metallic-film-based heater which can be operated in water. Based on the materials stability, Mo was selected as the heating element to secure long-term stability. Using a magnetron sputtering, 40 nm-thick Mo layers were deposited onto a glass substrate, followed by the deposition of 60-nm-thick ZnO layer to prevent oxidation during the heater fabrication process. Then, PVB (Polyvinyl Butyral) was applied on top of ZnO layer and an additional glass substrate was placed, which were heated at 150℃ for 2 hr. The PVB was cured with strong adhesion by the processing condition. We operated the Glass/Mo/ZnO/Glass heater in water, and it was shown that the water temperature reached 50℃ within 2 minutes, with a minimal resistance change of the heater. Finally, the heaters exhibit a semi-transparency, and this aesthetic advantage is expected to contribute to the added value of the heater.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.3 no.3
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• pp.139-148
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• 2022

Saxifraga hirculus is classified as a vulnerable plant species in Europe, and it is confined to base-rich flushes in the British uplands. However, a lack of available information about its conservation status hampers the development of adaptive strategies for its in-situ conservation, especially with respect to grazing. To assess the effectiveness of sheep grazing in maintaining viable populations of S. hirculus, we compared the community dynamics of the vegetation in a base-rich flush over 44 years in two plots: one sheep-grazed under business-as-usual sheep grazing densities and the other fenced to exclude grazing. The plots were established in 1972, and the abundances of all vascular plants, bryophytes, and litter were measured at six intervals until 2016. Our results showed that although the presence of S. hirculus was maintained in both plots over the 44 years, it declined and reached a minimum between 1995 and 2010, when it was close to extinction. Since 2013, Saxifraga has recovered only slightly. Interestingly, the S. hirculus response appeared to be independent of grazing treatment, but it mirrored wider changes in the vegetation composition and structure within the flush over the 44 years. These changes are similar to others reported in broader uplands that have been attributed to a combination of reduced nitrogen and sulfur deposition and global warming. Thus, the simple adaptive management approach of "just managing" sheep grazing appeared ineffectual for preserving the S. hirculus population. S. hirculus showed signs of recovery at the end of the study period within this base-rich flush.

• Advances in concrete construction
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• v.16 no.6
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• pp.291-302
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• 2023

As the first part of the body that strikes the ground during running, sports shoes are especially important for improving performance and reducing injuries. The use of new nanotechnology materials in the shoe's sole that can affect the movement angle of the foot and the ground reaction forces during running has not been reported yet. It is important to consider the material of the sole of the shoe since it determines the long-term performance of sports shoes, including their comfort while walking, running, and jumping. Running performance can be improved by polymer foam that provides good support with low energy dissipation (low energy dissipation). Running shoes have a midsole made of ethylene propylene copolymer (EPP) foam. The mechanical properties of EPP foam are, however, low. To improve the mechanical performance of EPP, conventional mineral fillers are commonly used, but these fillers sacrifice energy return. In this study, to improve the magnificence of physical education training with nanotechnology, carbon nanotubes (CNTs) derived from recycled plastics were prepared by catalytic chemical vapor deposition and used as nucleating and reinforcing agents. As a result of the results, the physical, mechanical, and dynamic response properties of EPP foam combined with CNT and zinc oxide nanoparticles were significantly improved. When CNT was added to the nanocomposites with a weight percentage of less than 0.5 wt%, the wear resistance, physical properties, dynamic stiffness, compressive strength, and rebound properties of EPP foams were significantly improved.

• Animal Bioscience
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• v.37 no.7
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• pp.1289-1302
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• 2024

Objective: There is a strong relationship between the content of beneficial fatty acids in milk and milk fat metabolic activity in the mammary gland. To improve milk quality, it is therefore necessary to study fatty acid metabolism in bovine mammary gland tissue. In adipose tissue, peroxisome proliferator-activated receptor gamma (PPARG), the core transcription factor, regulates the fatty acid metabolism gene network and determines fatty acid deposition. However, its regulatory effects on mammary gland fatty acid metabolism during lactation have rarely been reported. Methods: Transcriptome sequencing was performed during the prelactation period and the peak lactation period to examine mRNA expression. The significant upregulation of PPARG drew our attention and led us to conduct further research. Results: According to bioinformatics prediction, dual-luciferase reporter system detection, real-time quantitative reverse transcription polymerase chain reaction and Western blotting, miR-130a and miR-130b could directly target PPARG and inhibit its expression. Furthermore, triglyceride and oil red O staining proved that miR-130a and miR-130b inhibited milk fat metabolism in bovine mammary epithelial cells (BMECs), while PPARG promoted this metabolism. In addition, we also found that the coexpression of miR-130a and miR-130b significantly enhanced their ability to regulate milk fat metabolism. Conclusion: In conclusion, our findings indicated that miR-130a and miR-130b could target and repress PPARG and that they also have a functional superposition effect. miR-130a and miR-130b seem to synergistically regulate lipid catabolism via the control of PPARG in BMECs. In the long-term, these findings might be helpful in developing practical means to improve high-quality milk.

• Ecology and Resilient Infrastructure
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• v.6 no.1
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• pp.34-48
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• 2019

Naeseong Stream is a natural sand-bed river that flows through mountainous and cultivated area in northern part of Gyeongbuk province. It had maintained its inherent landscape characterized by white sandbars before 2010s. However, since then changes occurred, which include construction of Yeongju Dam and the extensive vegetation development around 2015. In this study, long-term monitoring was carried out on Naeseong Stream to analyze these changes objectively. This paper aims to provide a dataset of the investigation on channel morphology and vegetation for the period 2012-2018. Methods of investigation include drone/terrestrial photography, LiDAR aerial survey and on-site fieldwork. The main findings are as follows. Vegetation development in the channel of Naeseong Stream began around 1987. Before 2013 it occurred along the downstream reach and since then in the entire reach. Some of the sites where riverbed is covered with vegetation during 2014~2015 were rejuvenated to bare bars due to the floods afterwards, but woody vegetation was established in many sites. Bed changes occurred due to deposition of sediment on the vegetated surfaces. Though Naeseong Stream has maintained its substantial sand-bed characteristics, there has been a slight tendency in bed material coarsening. Riverbed degradation at the thalweg was observed in the surveyed cross sections. Considering all the results together with the hydrological characteristics mentioned in the precedent paper (I), it is thought that the change in vegetation and landscape along Naeseong Stream was mainly due to decrease of flow. The effect of Yeongju Dam on the change of the riverbed degradation was briefly discussed as well.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.5
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• pp.2565-2571
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• 2016

A cross-sectional survey was conducted among 730 participants from 4 rural districts of Nakhon Ratchasima province, Thailand, with a reported high incidence of liver fluke infection. This study was aimed to examine and evaluate the nutritional status in relation to Opisthorchis viverrini infection. Participants were purposive selected from Chum Phuang, Mueang Yang, Bua Yai, and Kaeng Sanam Nang districts. Stool samples were prepared by Kato Katz technique and then assessed by microscopy. Anthropometry was evaluated according to the body mass index from weight and height. Descriptive statistics and Spearman rank correlation coefficients were used to evaluate the association between the nutritional status and O. viverrini infection. Of 1.64% infected with O. viverrini the highest proportions were found in age groups ${\geq}61$ and 41-50 years old, Mueang Yang district. The majorities of participants had normal weight (32.2%), followed by class II obesity (28.1 %), class I obesity (21.8%), underweight (10.3%), and class III obesity (8.63%). Nutritional status with class II obesity (rS=0.639, p<0.01) and class I obesity (rS=0.582, p<0.05), had moderately statistical significant correlations with O. viverrini infection. Meanwhile, normal weight (rS=0.437, p<0.05) and class III obesity (rS=0.384, p<0.05) demonstrated lower statistical significance. These findings raise the possibility that infection with O. viverrini may contribute to fat deposition and thereby have long-term consequences on human health. Further studies are needed to better understand whether O. viverrini contributes directly to fat deposition and possible mechanisms.

• Journal of Korea Water Resources Association
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• v.39 no.6 s.167
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• pp.533-544
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• 2006

The deposition of solids in combined sewer systems results in a loss of flow capacity that may restrict flow and cause a local flooding and enhanced solids deposition. In order to solve these problems and proper pipe management, estimation of solid loads from sewer and surface in a drainage basin is needed but this task is very difficult and extremely expensive. In this study, generalized procedures for estimating sewer solid loads during dry weather in combined sewer systems and for estimating solid loads on surface in a drainage basin developed by the U. S. Environmental Protection Agency were applied and analyzed in Gunja drainage basin in Korea. As result, the estimated solid loads from sewer and surface are 205.8,759kg/yr and 1,321,993kg/yr respectively, and total solid loads is 1,527,752kg/yr. The estimated solid removal from street cleaning, dredging from pipe system and pumping house is 1,486,636kg/yr. Therefore, the applied methods show resonable results. More reliable estimation can be achieved if long-term measurements and adjustment of estimation equations are carried out, and this estimation methods can be used usefully for the management of combined sewer system with reduction of cost and effort.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.3
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• pp.229-238
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• 2007

In this paper, structural design requirements and safety evaluation criteria of the spent nuclear fuel disposal canister are studied for deep geological deposition. Since the spent nuclear fuel disposal canister emits high temperature heats and much radiation, its careful treatment is required. For that, a long term(usually 10,000 years) safe repository for the spent nuclear fuel disposal canister should be secured. Usually this repository is expected to locate at a depth of 500m underground. The canister which is designed for the spent nuclear fuel disposal in a deep repository in the crystalline bedrock is a solid structure with cast iron insert, corrosion resistant overpack and lid and bottom, and entails an evenly distributed load of hydrostatic pressure from underground water and high pressure from swelling of bentonite buffer. Hence, the canister must be designed to withstand these high pressure loads. If the canister is not designed for all possible external loads combinations, structural defects such as plastic deformations, cracks, and buckling etc. may occur in the canister during depositing it in the deep repository. Therefore, various structural analyses must be performed to predict these structural problems like plastic deformations, cracks, and buckling. Structural safety evaluation criteria of the canister are studied and defined for the validity of the canister design prior to the structural analysis of the canister. And structural design requirements(variables) which affect the structural safety evaluation criteria should be discussed and defined clearly. Hence this paper presents the structural design requirements(variables) and safety evaluation criteria of the spent nuclear fuel disposal canister.