• YAKHAK HOEJI
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• v.38 no.5
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• pp.562-567
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• 1994

Now para-phenylenediamine(PPDA) is generally used as component of most hairdyes because it can be used more conveniently and effectively than the others. But PPDA become known to cause side effects such as skin sensitization, contact dermatitis and eye irritation. So this study was done to restudy the safety of hairdyes containing PPDA. The results of experiment were as follows. 1. As a result of primary skin irritation test and eye irritation test in white rabbits, the solution containing 5% PPDA(in saline) were classified as weak irritant but four kinds of commercial hairdyes containing PPDA were proved not to have any irritation. 2. As a result of skin sensitization test in guinea pig, four kinds of commercial hairdyes were classified as Calss I(week irritant) but three kinds of commercial hairdyes induced skin sensitization for guinea pig to 5% in test groups. These results indicate that the actual toxicity of commercial hairdyes(four kinds) is negligible. But based on the results of experiment, it is thought that there is possibility of some commercial hairdyes to induce skin sensititization.

• Journal of Microbiology and Biotechnology
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• v.29 no.5
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• pp.731-738
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• 2019

Endophytic fungi are an important component of plant microbiota, and have the excellent capacity for producing a broad variety of bioactive metabolites. These bioactive metabolites not only affect the survival of the host plant, but also provide valuable lead compounds for novel drug discovery. In this study, forty-two endophytic filamentous fungi were isolated from Ficus elastica leaves, and further identified as seven individual taxa by ITS-rDNA sequencing. The antimicrobial activity of these endophytic fungi was evaluated against five pathogenic microorganisms. Two strains, Fes1711 (Penicillium funiculosum) and Fes1712 (Trichoderma harzianum), displayed broad-spectrum bioactivities. Our following study emphasizes the isolation, identification and bioactivity testing of chemical metabolites produced by T. harzianum Fes1712. Two new isocoumarin derivatives (1 and 2), together with three known compounds (3-5) were isolated, and their structures were elucidated using NMR and MS. Compounds 1 and 2 exhibited inhibitory activity against Escherichia coli. Our findings reveal that endophytic fungi from the rubber tree F. elastica leaves exhibit unique characteristics and are potential producers of novel natural bioactive products.

• Journal of Platform Technology
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• v.9 no.3
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• pp.24-35
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• 2021

High-speed military aircraft shall be able to identify and resolve enemy threats or internal component defects with survival equipment and warning systems to minimize casualties. Warning system is divided into visual method with symbolic display and auditory method with communication equipment, which is superior in that they it has a short response time and does not cause pilot confusion by listening to simple messages. Thus, this paper suggested and evaluated effective design methods of voice/tone warning systems for military aircraft based on a life cycle perspective. Since military aircraft is safety-sensitive, priorities and three properties(Inhibitible, Interruptible, and Deactivatable) were applied to each warning to reflect criticality and urgency. As a result, we confirmed that it took 40ms to play the voice warnings, satisfying all requirements through V model-based development and testing, and improving product reliability.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.269-277
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• 2022

In this paper, we overview the system development status of the national maritime precise point positioning-real-time kinematic (PPP-RTK) service in Korea, also known as the Precise POsitioning and INTegrity monitoring (POINT) system. The development of the POINT service began in 2020, and the open service is scheduled to start in 2025. The architecture of the POINT system is composed of three provider-side facilities-a reference station, monitoring station, and central control station-and one user-side receiver platform. Here, we propose the detailed functionality of each component considering unidirectional broadcasting of augmentation data. To meet the centimeter-level user positioning accuracy in maritime coverage, new reference stations were installed. Each reference station operates with a dual receiver and dual antenna to reduce the risk of malfunctioning, which can deteriorate the availability of the POINT service. The initial experimental results of a testbed from corrections generated from the testbed network, including newly installed reference stations, are presented. The results show that the horizontal and vertical accuracies satisfy 2.63 cm and 5.77 cm, respectively. For the purpose of (near) real-time broadcasting of POINT correction data, we designed a correction message format including satellite orbit, satellite clock, satellite signal bias, ionospheric delay, tropospheric delay, and coordinate transformation parameters. The (near) real-time experimental setup utilizing (near) real-time processing of testbed network data and the designed message format are proposed for future testing and verification of the system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.6
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• pp.377-384
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• 2022

In the design of composite aircraft structures, it is very important to set material allowables and design values, which take into account certification. And when determining the material allowable and design value of composite structures, the static strength, damage tolerance requirements, and environmental effects should be considered. The building block approach has been applied to the civil and military aviation industry for a long time and provides the principal certification methodology. This current certification methodology is based on extensive testing including coupon, element, sub-component, and full scale test. In this paper, some examples of composite allowable tests have been presented and the fundamental background and application methods of the building block approach have been presented.

• Journal of Distribution Science
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• v.20 no.2
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• pp.11-18
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• 2022

Purpose: The purpose of this paper is to investigate the influence of brand equity on customer purchase decision (CPD) of products for retailers distribution (RB) in Ho Chi Minh city, Vietnam. There are five elements in the brand equity model such as brand awareness, brand association, brand loyalty, perceived quality, and pricing policy. Research design, data and methodology: Qualitative methodology was used for exploring the research model and variables. The survey was conducted to collect data from 251 respondents who bought products at RB in Ho Chi Minh city, which is based on a Likert scale. The collected data were analyzed with the reliability of the scale, exploratory factor analysis, and research hypothesis testing by SPSS 22. Results: The results obtained revealed that brand awareness, brand association, perceived quality, and pricing policy have a significant impact on CPD for RB. Furthermore, the results showed that perceived quality is the most significant component in influencing CPD at retailers. Conclusions: From the research results, some management implications that RB should focus on are perceived quality, choice of pricing policies and strategies, brand building and development to attract more customers as well as enhance its image to improve customers' purchasing decisions of products at retail distributors chain.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.1003-1010
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• 2022

The purpose of this study was to examine the phytochemical compounds and antibacterial activity of Coffea robusta leaf extract (RLE). The results indicated that chlorogenic acid (CGA) is a major component of RLE. The minimum inhibitory concentrations (MICs) of RLE against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Salmonella Typhimurium were 6.25, 12.5, 12.5, and 12.5 mg/ml, respectively. RLE effectively damages the bacterial cell membrane integrity, as indicated by the high amounts of proteins and nucleic acids released from the bacteria, and disrupts bacterial cell membrane potential and permeability, as revealed via fluorescence analysis. Cytotoxicity testing showed that RLE is slightly toxic toward HepG2 cells at high concentration but exhibited no toxicity toward Caco2 cells. The results from the present study suggest that RLE has excellent potential applicability as an antimicrobial in the food industry.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.2
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• pp.383-393
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• 2022

At present, environmental problems are gradually becoming quite serious because of the expansion of the business scale of companies, factories, and enterprises, and that is also the reason for the global pollution of the world. Green entrepreneurship is playing an increasingly crucial role in influencing people's intentions, behaviors, and attitudes toward environmental protection through sustainable development. The purpose of this research was to examine the factors affecting university students' green entrepreneurship levels in Vietnam. To do this, we performed a scientific research survey with 773 students from reputable universities in Vietnam, 337 of whom are male and 436 of whom are female. To assess the reliability and correlation between observed and total variables, this study employs scale testing methods such as Cronbach alpha, EFA, CFA, and SEM. After evaluating the influencing elements, the findings reveal that the Subjective norm factor and the Risk-aversion component are two distinct aspects that influence university students' green entrepreneurship intentions in Vietnam and of which, the greatest influence is Risk Aversion. Furthermore, the findings revealed that the level of interest in green entrepreneurship is mostly seen by students with university education between the ages of 18-25.

• Smart Structures and Systems
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• v.31 no.2
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• pp.183-197
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• 2023

For long-span bridges with a structural health monitoring (SHM) system, environmental temperature-driven responses are proved to be a main component in measurements. However, anomalous structural behavior may be hidden incomplicated recorded data. In order to receive reliable assessment of structural performance, it is important to study therelationship between temperature and monitoring data. This paper presents an application of the cointegration based methodology to detect anomalies that may be masked by temperature effects and then forecast the temperature-induced deflection (TID) of long-span suspension bridges. Firstly, temperature effects on girder deflection are analyzed with fieldmeasured data of a suspension bridge. Subsequently, the cointegration testing procedure is conducted. A threshold-based anomaly detection framework that eliminates the influence of environmental temperature is also proposed. The cointegrated residual series is extracted as the index to monitor anomaly events in bridges. Then, wavelet separation method is used to obtain TIDs from recorded data. Combining cointegration theory with autoregressive moving average (ARMA) model, TIDs for longspan bridges are modeled and forecasted. Finally, in-situ measurements of Xihoumen Bridge are adopted as an example to demonstrate the effectiveness of the cointegration based approach. In conclusion, the proposed method is practical for actual structures which ensures the efficient management and maintenance based on monitoring data.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.104-104
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• 2022

Dendropanax morbiferus H. Lev has been reported to have some pharmacologic activities and also interested in functional cosmetics. We found that the water extract of D. morbiferus leaves significantly inhibited tyrosinase activity and melanin formation in α-melanocyte stimulating hormone (MSH)-induced B16-F10 cells. D. morbiferus reduced melanogenesis-related protein levels, such as microphthalmia? associated transcription factor (MITF), TRP-1, and TRP-2, without any cytotoxicity. Two active ingredients of D. morbiferus, (10E)-9,16-dihydroxyoctadeca-10,17-dien-12,14-diynoate (DMW-1) and (10E)-(?)-10,17-octadecadiene-12,14-diyne-1,9,16-triol (DMW-2) were identified by testing the anti-melanogenic effects and then by liquid chromatography-tandem mass spectrometry (LC/MS/MS) analysis. DMW-1 and DMW-2 significantly inhibited melanogenesis by the suppression of protein kinase A (PKA)/cyclic AMP (cAMP)-responsive binding protein (CREB) and p38 MAPK phosphorylation. DMW-1 showed a better inhibitory effect than DMW-2 in α-MSH-induced B16-F10 cells. D. morbiferus and its active component DMW-1 inhibited melanogenesis through the downregulation of cAMP, p-PKA/CREB, p-p38, MITF, TRP-1, TRP-2, and tyrosinase. These results indicate that D. morbiferus and DMW-1 may be useful ingredients for cosmetics and therapeutic agents for skin hyperpigmentation disorders.