Authors:Jae-Yong Choung, Hong-Ghi Min, and Myeong-Cheol Park
In recent years, the topic of knowledge production has been widely investigated in the advanced countries. However, the process
by which knowledge is produced in the developing countries has not been fully explored or characterized. In Korea, the science
and engineering fields strongly reflect systems of knowledge production in the universities and demonstrate the dynamics of
systems of innovation for knowledge production. Through using a case study including data for knowledge production, in the
field of information and telecommunication, the following general trends were observed. Firstly, there has been a trend towards
increasing the capabilities for knowledge production, via domestic and foreign collaboration. Secondly, there has been an
increasing trend towards the diversification of knowledge sources such as university-industry, and university-public research
institutes. Finally, the establishment of a nation's knowledge base is influenced by governmental research and development
Authors:Min Jeon, Jae Lee, Kweon Kang, Geun Park, Chang Lee, Jae Yang, and Chul Heo
Chlorination reaction behavior of Zircaloy-4 hull waste was investigated by using HSC chemistry code as a function of decladding
ratio. The Zircaloy-4 hull waste and residual spent nuclear fuel (SNF) remaining in the hull waste after oxidative decladding
process were considered as reactants of the chlorination reaction. It was assumed that the hull waste and residual SNF is
fed into the chlorination reaction after oxidative decladding at 700 °C, which might have cause partial/full oxidation of
the hull waste and residual SNF components. Reaction temperature for the theoretical calculation was set at 330 °C. The simulation
results suggested that solid phase chlorides (BaCl2, SrCl2, NdCl3, LaCl3, and RhCl3) are produced prior to formation of ZrCl4(g) and HfCl4(g). Although ZrCl4(g) is produced later than the solid products, it was expected that ZrCl4(g) can be easily separated from other chlorides as it is a gas phase at 330 °C. Therefore, it was concluded that the decladding
ratio might not affect formation of ZrCl4(g) when sufficient chlorine gas was supplied. Equilibrium composition analysis suggested that highly pure ZrCl4(g) with 0.006 mol.% of HfCl4(g) might be recovered from the hull waste via the chlorination reaction method.
Authors:Hye Park, Min Hong, Sun Hwang, Young Park, Ka Kwon, Jang Yoon, Sook Shin, Jae Kim, and Yong Park
Pseudomonas aeruginosa is one of the causative pathogens of bovine mastitis. Most P. aeruginosa strains possess the type III secretion system (TTSS), which may increase somatic cell counts (SCCs) in milk from mastitis-affected cows. Moreover, most of P. aeruginosa cells can form biofilms, thereby reducing antibiotic efficacy. In this study, the presence and effect of TTSS-related genotypes on increase of SCCs among 122 P. aeruginosa isolates obtained from raw milk samples from mastitis-affected cows and their antibiotic susceptibility at planktonic and biofilm status were investigated. Based on the presence of TTSS-related genes a total of 82.7% of the isolates were found to harbour exoU and/or exoS genes, including the invasive (exoU-/exoS+, 69.4%), cytotoxic (exoU+/exoS-, 8.3%) and cytotoxic/invasive strains (exoU+/ exoS+, 5.0%). Milk containing exoS-positive isolates had higher SCCs than those containing exoS-negative isolates. The majority of isolates showed gentamicin, amikacin, meropenem and ciprofloxacin susceptibility at planktonic status. However, the susceptibility was decreased at the biofilm status. Based on minimum biofilm eradication concentration (MBEC)/minimum inhibitory concentration (MIC) ratios, the range of change in antibiotic susceptibility varied widely depending on the antibiotics (from ≥ 3.1-fold to ≥ 475.0-fold). In conclusion, most P. aeruginosa isolates studied here had a genotype related to increase in SCCs. The efficiency of antibiotic therapy against P. aeruginosa-related bovine mastitis could be improved by analysing both the MBEC and the MIC of isolates.
Authors:Kwang-Wook Kim, Eil-Hee Lee, In-Kyu Choi, Jae-Hyung Yoo, and Hyun-Soo Park
The electrochemical redox behavior of nitric acid was studied using a glassy carbon fiber column electrode system, and its reaction mechanism was suggested and confirmed in several ways. Electrochemical reactions in less than 2.0M nitric acid was not observed. However, in more than 2.0M nitric acid, the reduction of nitric acid to nitrous acid occurred and the reduction rate was slow so that the nitric acid solution had to be in contact with an electrode for a period of time long enough for an apparent reduction current of nitric acid to nitrous acid to be observed. The nitrous acid generated in more than 2.0M nitric acid was rapidly and easily reduced to nitric oxide by an autocatalytic reaction. Sulfamic acid was confirmed to be effective to destroy the nitrous acid. At least 0.05M sulfamic acid was necessary to scavenge the nitrous acid generated in 3.5M nitric acid.
Authors:Gohar Feroz Khan, Junghoon Moon, Han Woo Park, Bobby Swar, and Jae Jeung Rho
Many researchers have analyzed e-government literature as a whole or a specific area to focus on statistical methodologies, lessons learnt, or problem related to the area. However, no investigation from socio-technical perspective on e-government issues, in developing countries (DCs), has been carried out. Utilizing scientometrics approach, we analyzed and synthesized e-government (EG) literature that deals with the issues/topics in developing countries from the lens of socio-technical theory (STT). 145 articles from 7 core e-government journals published during the last decade were selected and reviewed for analyzing e-government literature related to developing countries. The growth pattern of e-government literature showed that e-government studies pertaining developing countries issues/topics have rapidly increased during the last decade; covering a range of topics/issues studied from socio-technical aspects. We found that e-government literature in developing countries has somewhat adopted a balanced approach and is moving away from a merely theoretical or conceptual bases toward an empirical foundation; however, the literature lacked depth and balance in terms of issues/topics discussed and methodologies applied. In the light of the findings, strengths, limitations, and future directions for e-government research in developing countries are discussed.
Authors:SeonJu Park, Nanyoung Kim, Jun Hyung Park, Sang-Won Lee, Jae-Hyoung Song, Hyun-Jeong Ko, Han-Jung Chae, Hyung-Ryong Kim, and Seung Hyun Kim
Ixeris dentata (Thunb. ex Thunb.) Nakai (Asteraceae), a well-known edible vegetable in Asia, contains various bioactive secondary metabolites, including sesquiterpene lactones. In this study, a high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) method has been developed and validated for simultaneous determination of seven sesquiterpene lactone glucosides isolated from the roots of I. dentata. In addition, these compounds were evaluated in terms of their antiviral activities against coxsackievirus B3 (CVB3) and human enterovirus 71 (EV71). The developed method was validated in terms of linearity (R2 > 0.9996), precision (RSD < 2.24%), accuracy (96.30–102.77%), and stability (RSD < 1.94%) and successfully applied to the quantitation of the I. dentata root samples collected from six different regions of Korea. The content of sesquiterpene lactone glucosides varied significantly based on the region. For the antiviral activities, guaianolides with an ester group at C-8 (compounds 6 and 7) showed the most potent activities against CBV3, while germacranolide (compound 5) showed the most consistent antiviral activity against both CVB3 and EV71. The method was validated to be simple and reliable to simultaneously determine seven putative bioactive sesquiterpene lactone glucosides, the substantial chemotaxonomic markers, in I. dentata root samples.
Authors:Sung Jae Kim, Van Giap Nguyen, Cheong Ung Kim, Bong Kyun Park, Thi-My Le Huynh, Sook Shin, Woo Kyung Jung, Yong Ho Park, and Hee Chun Chung
Porcine epidemic diarrhoea virus (PEDV) is one of the major pathogens causing acute enteritis, which is characterised by vomiting and watery diarrhoea and commonly leads to high rates of mortality and morbidity in suckling piglets. Chitosan has been regarded as a promising natural disinfectant. In this study, the disinfectant effect and mammalian-cell toxicity of chitosan were evaluated against PEDV using Vero cells. A 0.01% solution of chitosan was determined to be an effective disinfectant. In addition, no evidence of toxicity was observed during the cell toxicity test; on the contrary, chitosan promoted cell proliferation. In conclusion, chitosan is a promising candidate for an effective and safe disinfectant against PEDV as well as other coronaviruses.
Authors:Kwang-Wook Kim, Jae-Won Lee, Dong-Young Chung, Eil-Hee Lee, Kweon-Ho Kang, Kune-Woo Lee, Kee-Chan Song, Myung-June Yoo, Geun-Il Park, and Jei-Kwon Moon
This work studied a way to reclaim uranium from contaminated UO2 oxide scraps as a sinterable UO2 powder for UO2 fuel pellet fabrication, which included a dissolution of the uranium oxide scraps in a carbonate solution with hydrogen peroxide
and a UO4 precipitation step. Dissolution characteristics of reduced and oxidized uranium oxides were evaluated in a carbonate solution
with hydrogen peroxide, and the UO4 precipitation were confirmed by acidification of uranyl peroxo–carbonate complex solution. An agglomerated UO4 powder obtained by the dissolution and precipitation of uranium in the carbonate solution could not be pulverized into fine
UO2 powder by the OREOX process, because of submicron-sized individual UO4 particles forming the agglomerated UO4 precipitate. The UO2 powder prepared from the UO4 precipitate could meet the UO2 powder specifications for UO2 fuel pellet fabrication by a series of steps such as dehydration of UO4 precipitate, reduction, and milling. The sinterability of the reclaimed UO2 powder for fuel pellet fabrication was improved by adding virgin UO2 powder in the reclaimed UO2 powder. A process to reclaim the contaminated uranium scraps as UO2 fuel powder using a carbonate solution was finally suggested.