• Journal of Life Science
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• v.31 no.2
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• pp.199-208
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• 2021

Euonymus porphyreus, a species of plant in the Celastraceae family, is widely distributed in East Asia, especially in Southern China. The botanical characteristics of E. porphyreus have been reported, but its antioxidative and anticancer activities remain unclear. In this study, we evaluated the antioxidative and anticancer effects of ethanol extracts of E. porphyreus (EEEP) and the molecular mechanism of its anticancer activity in human lung adenocarcinoma A549 cells. The total polyphenol and flavonoid compound contents from EEEP were 115.42 mg/g and 23.07 mg/g, respectively. EEEP showed significant antioxidative effects with a concentration at 50% of the inhibition (IC50) value of 11.09 ㎍/ml, as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. EEEP showed cytotoxic activity by increasing the SubG1 cell population of A549 cells in a dose-dependent manner. Apoptosis in A549 cells treated with EEEP was evident due to increased apoptotic cells and apoptotic bodies, as detected by Annexin V and 4,6-diamidino-2-phenylindole (DAPI) staining, respectively. EEEP-induced apoptosis resulted in increased expression of the First apoptosis signal (Fas), p53, and Bax, with decreased expression of Bcl-2 and subsequent activation of caspase-8, -9, and caspase-3, leading to cleavage of poly (ADP-ribose) polymerase (PARP). Collectively, these results suggest that EEEP may exert an anticancer effect by inducing apoptosis in A549 cells through both intrinsic and extrinsic pathways.

• Journal of the Korean Geotechnical Society
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• v.37 no.3
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• pp.19-30
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• 2021

The presence of the hydrate-bearing sediments in Ulleung Basin of South Korea has been confirmed from previous studies. Researches on gas production methods from the hydrate-bearing sediments have been conducted worldwide. As production mechanism is a complex phenomenon in which thermal, hydraulic, and mechanical phenomena occur simultaneously, it is difficult to accurately conduct the productivity and stability analysis of hydrate bearing sediments through lab-scale experiments. Thus, the importance of numerical analysis in evaluating gas productivity and stability of hydrate-bearing sediments has been emphasized. In this study, the numerical parametric analysis was conducted to investigate the effects of the bottom hole pressure and the depressurization rate on the gas productivity and stability of hydrate-bearing sediments during the depressurization method. The numerical analysis results confirmed that as the bottom hole pressure decreases, the productivity increases and the stability of sediments deteriorates. Meanwhile, it was shown that the depressurization rate did not largely affect the productivity and stability of the hydrate-bearing sediments. In addition, sensitivity analysis for gas productivity and stability of the sediments were conducted according to the depressurization rate in order to establish a production strategy that prevents sand production during gas production. As a result of the analysis, it was confirmed that controlling the depressurization rate from a low value to a high value is effective in securing the stability. Moreover, during gas production, the subsidence of sediments occurred near the production well, and ground heave occurred at the bottom of the production well due to the pressure gradient. From these results, it was concluded that both the productivity and stability analyses should be conducted in order to determine the bottom hole pressure when producing gas using the depressurization method. Additionally, the stress analysis of the production well, which is induced by the vertical displacements of sediments, should be evaluated.

• Journal of Applied Biological Chemistry
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• v.64 no.2
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• pp.185-192
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• 2021

Psoriasis is a chronic intractable skin disease caused by various inflammatory cytokines such as IL-6, CXCL8, TNF-α, and IFN-γ, as well as IL-17A secreted from Th17 cells and is characterized by hyperkeratosis and chronic inflammation of the epidermis. Brazilin, an active ingredient of Caesalpinia sappan L., is known to exert antioxidant and anti-inflammatory activity, and function in skin barrier improvement. In particular, it was shown as a potential material for treating psoriasis in a tumor necrosis factor (TNF)-α-stimulated HaCaT keratinocyte model. However, the direct regulation of the C-C motif chemokine ligand (CCL) 20, a psoriasis-inducing factor, by brazilin has not been reported. Therefore, in this study, we investigated the suppression of CCL20 and the regulatory mechanism by brazilin using a psoriasis-like model. First, brazilin downregulated CCL20 and CXCL8 in IL-17A-stimulated HaCaT cells in a concentration-dependent manner by inhibiting signal transducer and transcription (STAT)3 phosphorylation. In addition, brazilin significantly inhibited the expression of psoriasis-related genes CXCL8, CCL20, IL-1, IL-6, and TNF-α in TNF-α/IL-17A/IFN-γ-stimulated HaCaT cells. Moreover, brazilin also had a positive effect on improving the skin barrier in TNF-α/IL-17A/IFN-γ-stimulated HaCaT cells. The above results indicated that brazilin ultimately downregulated CCL20 expression by inhibiting STAT3 phosphorylation, and also suppressed the expression of psoriasis-induced cytokines. If the efficacy of brazilin in improving psoriasis is verified through animal models and clinical trials in the future, it may represent a potentially therapeutic substance for psoriasis patients.

• Economic and Environmental Geology
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• v.54 no.6
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• pp.709-716
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• 2021

In this study, an adsorbent prepared by natural drying of iron hydroxide-based sludge collected from settling basin at a mine drainage treatment facility located in Gangneung, Gangwon-do was used to remove fluoride in an artificial fluoride solution and mine drainage, and the adsorption characteristics of the adsorbent were investigated. As a result of analyzing the chemical composition, mineralogical properties, and specific surface area of the adsorbent used in the experiment, iron oxide (Fe₂O₃) occupies 79.2 wt.% as the main constituent, and a peak related to calcite (CaCO₃) in the crystal structure analysis was analyzed. It was also identified that an irregular surface and a specific surface area of 216.78 m²·g^-1. In the indoor batch-type experiment, the effect of changes in reaction time, pH, initial fluoride concentration and temperature on the change in adsorption amount was analyzed. The adsorption of fluoride showed an adsorption amount of 3.85 mg·g^-1 16 hours after the start of the reaction, and the increase rate of the adsorption amount gradually decreased. Also, as the pH increased, the amount of fluoride adsorption decreased, and in particular, the amount of fluoride adsorption decreased rapidly around pH 5.5, the point of zero charge at which the surface charge of the adsorbent changes. Meanwhile, the results of the isotherm adsorption experiment were applied to the Langmuir and Freundlich isotherm adsorption models to infer the fluoride adsorption mechanism of the used adsorbent. To understand the thermodynamic properties of the adsorbent using the Van't Hoff equation, thermodynamic constants 𝚫H° and 𝚫G° were calculated using the adsorption amount information obtained by increasing the temperature from 25℃ to 65℃ to determine the adsorption characteristics of the adsorbent. Finally, the adsorbent was applied to the mine drainage having a fluoride concentration of about 12.8 mg·L^-1, and the fluoride removal rate was about 50%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.1
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• pp.7-13
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• 1989

The present study was carried out to get the basic information for clarifying physiological mechanism of breaking dormancy and sprouting in Panax ginseng roots. Changes in Abscisic acid (ABA) content and Gibberellin (GA) activity were investigated in one-year-old root during stratification at 4$^{\circ}C$. 15$^{\circ}C$. and 15$^{\circ}C$ after 60day-treatment at 4$^{\circ}C$. Sprouting rate at 15$^{\circ}C$ was 35％ in 30days storage at 4$^{\circ}C$ and 100％ in longer than 60days, but there was no sprout in both the constant treatment at 4$^{\circ}C$ or 15$^{\circ}C$ regardless of the treatment period. The longer the period of low temperature treatment. number of days to the first and 50％ sprouting was shortened, and number of days to 50％ from first sprouting was also shortened. ABA content in the upper part of root(contained bud) was gradually increased at both 4$^{\circ}C$ and 15$^{\circ}C$ as the treatment period was extended. and the degree of increase was higher at 15$^{\circ}C$. In the lower part. it showed a slight increase at 15$^{\circ}C$. while showed little change at 4$^{\circ}C$ throughout the treatment period. In the 15$^{\circ}C$ treatment after 60days at 4$^{\circ}C$, it was greatly increased in the upper part. while rather slightly decreased in the lower part of root. GA activity in the upper part was gradually decreased at both 4$^{\circ}C$ and 15$^{\circ}C$, and the degree of decrease was higher at 15$^{\circ}C$. In the lower part. it was similar tendency to those in the upper part. In the 15$^{\circ}C$ treatment after 60days at 4$^{\circ}C$. it was remarkably increased in both the upper and lower part. The increase was great in the low Rf region, while the decrease appeared relatively in the high Rf region compared to those of 60day-treatment at 4$^{\circ}C$. The above results indicated that the breaking dormancy and sprouting of bud were closely associated with the degree of GA activities in response to temperature condition .during stratification rather than the direct effect associated with the changes in ABA content.

• Journal of Life Science
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• v.33 no.2
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• pp.169-175
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• 2023

As a protective defensive mechanism against ultraviolet (UV) light exposure in skin tissue, melanocytes produce the pigment melanin. Tyrosinase plays a key role in melanin production in melanocytes. However, the overproduction of melanin can lead to lesions, such as freckles and dark spots. Thus, it is clinically important to find a modulating molecule to control melanogenesis by regulating tyrosinase expression and/or activity. It is known that catechin, a plant flavonoid, can reduce melano- genesis through the downregulation of tyrosinase expression. Here, we tested whether catechin derivatives isolated from the stem bark of Ulmus parvifolia have an effect on melanin production by regulating tyrosinase in mouse melanoma cells and in vitro mushroom tyrosinase. The catechin derivatives used in this study included C5A, C7A, C7G, and C7X. Treatments using these catechin derivatives reduced melanin production in mouse melanoma B16F10 cells in which melanogenesis was stimulated by α-MSH. Notably, the anti-melanogenic effects of catechin derivatives were similar to those of kojic acid, a well-known anti-melanogenic molecule. Both C5A and C7A directly inhibited the activity of tyrosinase isolated from mushrooms in vitro. Furthermore, our in silico computational simulation showed that these two compounds were expected to bind to the active site of tyrosinase, which is similar to kojic acid. In addition, all four catechin derivatives reduced tyrosinase protein expression. In summary, our results showed that catechin derivatives can reduce melanogenesis by regulating tyrosinase activity or expression. Thus, this study suggests that catechin derivatives isolated from U. parvifolia can be novel modulators of melanin production.

• Journal of Service Research and Studies
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• v.13 no.2
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• pp.146-160
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• 2023

The spread of non-face-to-face services due to the COVID-19 pandemic has brought many changes in consumers' purchasing behavior and attracted much attention to new services. Could trying new services caused by this sudden environmental change alter consumers's choice patterns? This study proposes the research question of whether these new service experiences can change consumers' existing choice behavior, especially for risk-averse consumers who maintain their existing choice behavior or prefer safe alternatives. In this study, we examined whether trying out an unmanned payment services, one of innovative services that emerged after the pandemic crisis, can change the existing choice behavior of risk-averse consumers, i.e., make them more likely to prefer risky alternatives to safe alternatives. To accomplish these research goals, this research conducted one pilot survey and one study. The results of pilot survey showed that the stronger the prevention-focus tendency, the lower the self-efficacy to use the innovative service, with a negative relationship between them. Based on these findings, the study used an experimental method to examine the interaction effects between the use of innovation services and consumers' regulatory focus in a choice behavior and to explore the psychological mechanisms behind them. According to the results, it is found that prevention-focused consumers were more likely to choose risky alternatives and dissimilar extended brands following a trial of an unmanned payment service compared to not using that service. In contrast, promotion-focused consumers did not show different choice patterns regardless of following a trial of an innovative service. Furthermore, these results for prevention-focused consumers confirm the role of self-efficacy as a psychological mechanism. These findings shed light on the role of self-efficacy which has discussed in positive psychology into marketing area. Moreover, practical and academic implications are suggested by the finding that behavioral change occurs in risk-averse consumers, who are known to be hesitant to try new behaviors, indicating market expansion related to potential consumers for the use of the innovation services.

• Economic and Environmental Geology
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• v.56 no.3
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• pp.301-310
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• 2023

Ferrihydrite is an iron oxide mineral that is easily found in the natural environment, including acid mine drainage, and has a low crystallinity and high specific surface area, resulting in high reactivity with other ions, and can remove environmentally hazardous substances. However, because ferrihydrite is a metastable mineral, there is a possibility of releasing adsorbed ions by phase transformation to other minerals having low surface area and high crystallinity. In this study, the adsorption characteristics of arsenate, chromate, and selenate on ferrihydrite and the oxyanion removal efficiency of ferrihydrite were studied considering mineral phase transformation. At both pH 4 and 8, the adsorption of oxyanions used in the study were in good agreement with both Langmuir and Freundlich adsorption models except for selenate at pH 8. Due to the difference in surface charge according to pH, at pH 4 a higher amount of ions were adsorbed than at pH 8. The adsorption amount were in the order of arsenate, chromate, and selenate. These different adsorption models and adsorption amounts were due to different adsorption mechanisms for each oxyanions on the surface of ferrihydrite. These adsorption characteristics were closely related to changes in the mineral phase. At pH 4, a phase transformation to goethite or hematite was observed, but only a phase transformation to hematite was observed at pH 8. Among the oxyanion species on ferrihydrite, arsenate showed the highest adsorption capacity and hardly caused phase transformation during the experimental period after adsorption. Contrary to this, chromate and selenate showed faster mineral phase transformation than arsenate, and selenate had the lowest retardation effect among the three oxyanions. Ferrihydrite can effectively remove arsenate due to its high adsorption capacity and low phase transformation rate. However, the removal efficiency for other two oxyanions were low by the low adsorption amount and additional mineral phase transformation. For chromate, the efficient removal is expected only at low concentrations in low pH environments.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.6
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• pp.195-208
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• 2022

The role of venture CEO and their intrinsic capabilities on organizational performance can be determined by the level of resource synchronization initiated by the focal managers. Despite the important role of venture CEOs, a systematic lack of in-depth theoretical and empirical studies on ruminating the relationship between the effects of a CEO's capabilities and organizational performance depending on the level of resource synchronization exist for the rationale of investigation. To supplement the limitations of previous studies, this research empirically analyzes the role of managers specifically synchronizing organizational resources that affect organizational performance in the professional sports industry. Based on the entrepreneurship theory and resource-based view (RBV), this research conceptualizes the roles of venture CEO and basketball head coach in the professional sports industry as very similar in terms of organizational structure and performance mechanism embedding entrepreneurial characteristics necessary for managing organizational resources. In this research, we hypothesized (1) organizational resource synchronization will mediate the positive relationship between the ability of professional basketball head coach and organizational performance and (2) the indirect effect of the professional basketball head coach's capabilities on organizational performance mediated by resource synchronization will be moderated by the capabilities of players. To test these hypotheses, we utilized the PROCESS macro model 58 with the empirical data of 9 seasons (2013~2014-2021~2022) of 30 National Basketball Association (NBA) and 10 Korean Basketball League (KBL) teams. The statistical results showed that (1) resource synchronization mediates the positive relationship between professional basketball head coach capabilities and organizational performance and (2) the capabilities of players moderated the indirect effects of the abilities of head coaches on team performance via resource synchronization. This paper contributes to both academic and practical domains of entrepreneurship by empirically testing the research model through objective professional sports data.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.6
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• pp.87-104
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• 2023

Recently, concerns are growing over small and medium-sized companies holding out on debt as domestic loan interest rates have risen sharply due to the prolonged impact of COVID-19 and soaring raw material prices. In addition, loans from small and medium-sized enterprises, which are difficult in the business environment, are increasingly being rejected due to high loan interest rates and excessive submission documents and financial statements-oriented screening of loans by the financial sector. Therefore, since it is necessary to discuss ways to promote financing and investment by SMEs, this study intends to suggest ways to promote investment through the use of SMEs' ESG systems. The purpose of this study is to suggest that the use of ESG evaluation indicators used as non-financial indicators helps predict the corporate value of SMEs and the importance of SMEs actively participating in ESG information disclosure. This study suggests the necessity of introducing and practicing ESG by SMEs where financing is important, and aims to analyze as an empirical result that the use of non-financial indicators helps predict corporate value. As a result of the study, the ESG performance and corporate value of SMEs showed a positive (+) relationship. It can be seen that both the grades and corporate value of SMEs by ESG sector have a positive (+) influence relationship. The total ESG rating was confirmed to have a positive effect on corporate value, and it was confirmed that SMEs with higher ESG environment, social, and governance ratings were evaluated higher. According to the research results, it is suggested that SMEs also need to use ESG evaluation indicators, and in order to promote the growth of SMEs, it is suggested that research on ways to re-examine the corporate value of SMEs is necessary. Therefore, this study suggests that the use of ESG should be actively recommended and implemented as a way to establish a management strategy for SMEs, and that efforts to disclose ESG information can soon help SMEs solve information asymmetry. In addition, SMEs want to understand the investment mechanism that the introduction and practice of ESG can lead to the improvement of the value of SMEs and suggest the necessity of SME-type ESG policies in the future.