• Analytical Science and Technology
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• v.36 no.6
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• pp.281-290
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• 2023

Zidovudine is an antiretroviral agent prescribed for the prevention and treatment of human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS). It is typically recommended to be used in combination with other antiretroviral drugs. Zidovudine has the potential to generate N-nitrosodimethylamine (NDMA) in the presence of dimethylamine and nitrite salt under acidic reaction conditions during the drug manufacturing process. NDMA is a potent human carcinogen that may be detected in drug substances or drug products. An analytical method was developed to determine NDMA in pharmaceuticals including zidovudine using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The analysis involved reversed-phase chromatography on a Kinetex F5 column with a mobile phase comprising water-acetonitrile mixtures. The detection of positively charged ions was conducted using atmospheric pressure chemical ionization (APCI). The calibration curve demonstrated excellent linearity (r = 0.9997) across the range of 1-50 ng/mL with a highly sensitive limit of detection (LOD) at 0.3 ng/mL. The developed method underwent thorough validation for specificity, linearity, accuracy, precision, robustness, and system suitability. This sensitive and specific analytical method was applied for detecting NDMA in zidovudine drug substance and its formulation currently available in the market, indicating its suitability for drug quality management purposes.

• Food Science and Preservation
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• v.16 no.6
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• pp.965-970
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• 2009

PCR technology has been widely used to detect and quantify microbial pathogens in foodstuffs, because the technique is rapid, sensitive, and selective. In this study, detection of contaminating pathogenic bacteria on shells of chicken eggs was performed using both a commercial multiplex polymerase chain reaction (PCR) kit and a viable count method employing a selective medium. The PCR kit was capable of detecting Campylobacter jejuni, Escherichia coli O157:H7, Staphylococcus aureus, Bacillus cereus, Vibrio parahaemolyticus, Listeria monocytogenes, Yersinia enterocolitica, Salmonella species, and Shigella species. Using the PCR method, five bacterial species were detected from 30 samples (33.3%) of 90 batches of eggs commercially available in a market. PCR products from B. cereus, S. aureus, L. monocytogenes, Y. enterocolitica, and E. coli O157:H7 were detected, and the numbers and frequencies of positive samples were 17 (18.8%), 12 (13.3%), 15 (16.6%), 16 (17.7%),and 4 (4.4%), respectively. None of any Salmonella species, C. jejuni, V. parahaemolyticus, or Shigella species was detected in this study. The results of PCR testing were confirmed using a typical viable count method employing a selective medium. We suggest that the multiplex polymerase chain reaction (mPCR) assay is a rapid and reliable method for detection of pathogenic bacteria contaminating eggs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6610-6617
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• 2013

This study examined the current and future Indoor Air Quality (IAQ) control device markets and analyzed the recent studies on indoor air pollutantr emoval to develop a new technology for fine dust control. Currently, the mechanical filter technique occupies the bulk of the IAQ control market but the electronic technique is emerging as an alternative to control fine dust efficiently. Among the gaseous VOCs and fine dust particles contaminating the indoor air quality, fine dust particles are more problematic because they threaten human health by penetrating deep into the body and producing secondary contaminants by chemical reaction with VOCs. The electronic IAQ control device using dielectrophoretic and electrostatic forces is a good option for public spaces where many people pass, and at the same time, it needs to consider temperature, humidity, and the particle properties of specific areas to highlight the control efficiency. Electronic-related technology is expected to be used widely in many public/private spaces wherever a dust-free environment is required.

• The Journal of Industrial Distribution & Business
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• v.10 no.5
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• pp.27-36
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• 2019

Purpose - Naver has emerged as a new leader in the open market. While existing open markets such as Gmarket, 11th Street, and so on are suffering from profitability deterioration, Naver is attracting sellers based on low commission and powerful search engine. We would like to analyze the impact of Naver shopping on the national economy, especially on employment, in a situation where the market reaction to Naver's strength as a leader in online shopping is mixed. Research Design, Data, and Methodology - Through the demand inducing inter-industry analysis, we estimate the employment inducement effect by Naver shopping from its shopping transaction. In turn, through the supply inducing inter-industry analysis, we estimate the employment inducement effect by Naver shopping from its low commission and powerful search engine. For the purpose of inter-industry analysis, as of 2018, the most recently announced 2014 inter-industry table (extension table) from the Bank of Korea is used. Results - The results of this study are as follows. First, Naver Shopping is expected to generate 7.8 trillion won's trade in 2018, resulting in 244,225 of job inducement, and 158,598 of employment inducement. In addition, Naver Shopping is estimated to benefit KRW 213 billion to its sellers due to low commission and powerful search function, resulting in 8,667 of job inducement, and 5,655 of employment inducement. Second, in terms of job inducement and employment inducement due to Naver Shopping's trade, transportation, business support service, information and communication, broadcasting, restaurants and lodging were ranked. Third, in terms of job inducement and employment inducement due to Naver Shopping's low commission and powerful search function, restaurants and hospitality, f/b and cigarette manufacturing, construction, and transportation equipment manufacturing were ranked. Conclusions - The number of job inducement resulting from low commission and powerful search engine of Naver shopping in 2018 was 8,667 (3.7% of 244,225, which was caused by transaction in Naver shopping in 2018), and employment inducement was 5,655 (3.7% of 158,598, which was caused by transaction in Naver shopping in 2018), which can be considered as additional employment impacts of Naver Shopping compared to the other online shopping operators.

• The Journal of the Korea Contents Association
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• v.16 no.9
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• pp.600-611
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• 2016

This study examined the impacts of types of titles of artworks, especially 'untitled', on audience reponse. Generally, naming can be a tool to represent characteristics of objects, affecting their market value and price. Since contemporary artworks are often untitled, this study aimed to investigate how naming 'untitled' would affect audience response. As the size of arts market increasing, how the audience, potential buyer of artworks, responds to artworks is important. Based on prior research, we hypothesized that the audience would have different level of understanding, attention, attractiveness and curiosity to untitled artworks, controlling other factors. In the regression results from the data of 305 respondents, we found that people had significantly lower level of understanding and attention on untitled artworks than on artworks of explanatory or associative titles. In addition, respondents showed significantly higher level of curiosity when the artwork was an painting. This study confirmed the assertions of prior research that titles are indeed important, and further implied that artwork creators should be more concerned on naming their artworks since titles as well as artworks themselves could actually affect audience response.

• Proceedings of the Korea Port Economic Association Conference
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• 2006.08a
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• pp.1-12
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• 2006

As national economies globalize, demand for intercontinental container shipping services is growing rapidly, providing a potential economic boon for the countries and communities that provide port services. On the promise of profits, many governments are investing heavily in port infrastructure, leading to a possible glut in port capacity, driving down prices for port services and eliminating profits as ports compete for business. Further, existing ports are making strategic investments to protect their market share, increasing the chance new ports will be overcapitalized and unprofitable. Governments and port researchers need a tool for understanding how local competition in their region will affect demand for port services at their location, and thus better assess the profitability of a prospective port. We propose to develop such a tool by extending our existing simulation model of global container traffic to incorporate demand-side shipper preferences and supply-side strategic responses by incumbent ports to changes in the global port network, including building new ports, scaling up existing ports, and unexpected port closures. We will estimate shipper preferences over routes, port attributes and port services based on US and international shipping data, and redesign the simulation model to maximize the shipper's revealed preference functions rather than simply minimize costs. As demand shifts, competing ports will adjust their pricing (short term) and infrastructure (long term) to remain competitive or defend market share, a reaction we will capture with a game theoretic model of local monopoly that will predict changes in port characteristics. The model's hypotheses will be tested in a controlled laboratory experiment tailored to local port competition in Asia, which will also serve to demonstrate the subtle game theoretic concepts of imperfect competition to a policy and industry audience. We will apply the simulation model to analyze changes in global container traffic in three scenarios: addition of a new large port in the US, extended closure of an existing large port in the US, and cooperative and competitive port infrastructure development among Korean partner countries in Asia.

• International Area Studies Review
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• v.20 no.2
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• pp.3-23
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• 2016

In this study, we used actual proof analysis, based on SVAR model according to economy theory, to observe the impact of actual and financial market of Korea, Japan, and China that have adopted quantitative easing export based strategy of growth, an unconventional monetary policy of the U.S. As a result of estimation, it appears that real effective exchange rate rise shock of Korea, Japan, and China against U.S. dollar has a negative influence on current account and index of industrial product, which are real economy. It can be implied that the result is driven from the fact that strong home currency of Korea, Japan, and China decreases price competitiveness of exports, causing negative influence on real economy. The real effective exchange rate shock against U.S. dollar appeared to decrease national bond rate of Korea and Japan, while increasing that of China. In instances of Korea and Japan, it is implied that national bond rate decreases as foreigner investment funds flow in, considering foreign-exchange profit through advanced financial market with high opening extent. On the other hand, because there are strong regulation on opening extent of Chinese financial markets, the influence seems to be greater for domestic policy, rather than a foreign influence. Lastly, Korea showed a more dramatic variable reaction to exchange rate shock compared to Japan or China. It is implied from the result that Korea is relatively more susceptible and fragile in regards of international status of economic size and currency.

• International Area Studies Review
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• v.15 no.1
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• pp.87-106
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• 2011

Using an event study, this paper investigates stock price reactions on Korean listed firms' convertible bond (CB) issue announcements over the sample period of January 2000 to November 2007. This study finds that on the Korean Security market, the CB issue announcements are associated with an increase in shareholder wealth on the announcement date. An information leakage by insider traders is also observable at preannouncement dates. Unlike the prior studies that indicate a prevailing negative effect on the announcements, this paper shows that domestic CB issue announcements as well as offshore ones yield a positive impact on the stock prices. This presents that in terms of stock price reactions to the CB issue announcements, the two CB issue markets show the positively same effects on shareholder wealth for the post-2000 period. For its drivers, this paper suggests that on the Korean market, firm size have negative relationship with the increase in the wealth incurred by the announcements. By contrast, an issue to maturity, a growth opportunity, and a relative issue size make a positive impact on it.

• Korean Journal of Food Science and Technology
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• v.26 no.3
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• pp.300-304
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• 1994

To predict quality change of Kochujang distributed in the market, physicochemical properties were observed during storage at $13^{\circ}C$, $27^{\circ}C$ and $37^{\circ}C$ for 240 days. Moisture, crude protein and capsaicin contents were nearly constant for storage at the selected temperatures. Amino nitrogen, value of surface color and pH were decreased during storage while ammonia nitrogen and titratable acidity were increased. Storage temperature affected quality change significantly as higher temperature showed clear increase or decrease phenomena of above factors. Number of total cell count was not changed significantly, and fungi was not detected. From the correlation coefficient among physicochemical properties and sensory evaluation scores, the highest correlation was obtained in amino nitrogen content and sensory score. Degradation of amino nitrogen was a first order reaction, and the $Q_{10}$ value calculated from reaction constant was 2.98. Also, activation energy for the destruction of amino nitrogen calculated from Arrhenius equation was 15.34 Kcal/mole.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.141-155
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• 2017

In the present paper, we investigated the development status of precipitated calcium carbonate (PCC) production using steel slag, which is one of mineral carbonation (MC) technologies, from the standpoint of $CO_2$ utilization. Principle, feature, and global and domestic development status of the mineral carbonation technology were discussed together with the overview of the production method and market of PCC. Mineral carbonation is known as stable and environmentally-friendly technology enabling economical treatment of industrials wastes. Typically, PCC is produced by the reaction of $CO_2$ with supernatant solution after Ca extraction from steel slag followed by the separation of solid and liquid. The development status of MC using steel slag is at the pilot stage (Slag2PCC at Aalto University), and there remains the process economics improvement for commercialization. Key technologies for the further development are efficient extraction of Ca ions from steel slag including impurities removal, valorization of PCC via shape and size control, usage development and value-addition of residual slag, and optimization of reaction conditions for continuous process setup, etc.