• Korean Journal of Environmental Biology
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• v.41 no.2
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• pp.126-137
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• 2023

Paddy fields provide important habitats for biodiversity conservation within the agricultural ecosystem. Their importance is gradually increasing as their ecological value is better understood. Benthic macroinvertebrates dominate paddy fields. They play an essential role in maintaining the biodiversity of paddy ecosystems. This study aimed to analyze characteristics of benthic macroinvertebrate communities and main environmental factors affecting the distribution of golden apple snails (Pomacea canaliculata). Results showed that the diversity index (H') of the benthic macroinvertebrate community was the highest at the Sangju site (St. 12) but the lowest at the Sancheong site (St. 18). Total Dissolved Solids (TDS), salinity, and Electrical Conductivity (EC) values were the highest in Gimhae and Yeongam based on Canonical Correspondence Analysis (CCA). Numbers of P. canaliculata (m-2) were relatively low in Gunsan and Iksan where water temperatures were high. Therefore, changes in geographical characteristics and environmental factors might affect the distribution of P. canaliculata and characteristics of benthic macroinvertebrate communities. Results of this study can be used as primary data for biodiversity conservation and ecosystem service evaluation in agroecosystems.

• Genomics & Informatics
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• v.13 no.1
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• pp.15-24
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• 2015

Fatty acid synthase (FASN, EC 2.3.1.85), is a multi-enzyme dimer complex that plays a critical role in lipogenesis. This lipogenic enzyme has gained importance beyond its physiological role due to its implications in several clinical conditions-cancers, obesity, and diabetes. This has made FASN an attractive pharmacological target. Here, we have attempted to predict the theoretical models for the human enoyl reductase (ER) and ${\beta}$-ketoacyl reductase (KR) domains based on the porcine FASN crystal structure, which was the structurally closest template available at the time of this study. Comparative modeling methods were used for studying the structure-function relationships. Different validation studies revealed the predicted structures to be highly plausible. The respective substrates of ER and KR domains-namely, trans-butenoyl and ${\beta}$-ketobutyryl-were computationally docked into active sites using Glide in order to understand the probable binding mode. The molecular dynamics simulations of the apo and holo states of ER and KR showed stable backbone root mean square deviation trajectories with minimal deviation. Ramachandran plot analysis showed 96.0% of residues in the most favorable region for ER and 90.3% for the KR domain, respectively. Thus, the predicted models yielded significant insights into the substrate binding modes of the ER and KR catalytic domains and will aid in identifying novel chemical inhibitors of human FASN that target these domains.

• Journal of Dairy Science and Biotechnology
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• v.14 no.1
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• pp.1-15
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• 1996

With the starting of Uruguay Round(UR) and World Trade Organization(WTO), the direction of trade in world market has been setting up with the beginning of an opening age. However, world nations has been expressed a deep concern on the marketing and the circulations of unsafe foods, especially in the international trade of food products. Therefore, administration of most countries are taking a firm step on the safety of imported food products. The implementation of hazard analysis critical control point(HACCP) system in food industry is strongly appeared on the world stage at this point. Major international organizations, such as WHO, WTO, and EC have been recognized the importance of HACCP and already documented on their future plan for standardization of food safety in the international trade of food products by means of the this system. Several advanced countries have already developed HACCP system for the food industry and have been producing food products under this system. Now they have proposed rulemakings on a mandatory HACCP program in the production of domestic and imported food products. However, with the lacking of knowledge and information on the HACCP, there has been no actions for applying this system in the food industry of Korea. It is a very clear fact that Korean dairy and food industry will be faced on serious problems in exporting food products without applying HACCP system in the very near future. The objective of this article is to introduce the world trend. necessity, and application of HACCP system in food and dairy industry. Also a HACCP system developed by one dairy processing plant in Europe will be demonstrated as a moldel system.

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.1925-1930
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• 2011

Psychrophilic bacteria have acquired cold-resistance in order to protect themselves against freezing temperatures, which would otherwise be lethal. DnaK/DnaJ/GrpE systems are molecular chaperones which facilitate proper folding of newly synthesized proteins. Efficient folding processes are of great importance especially in a cold environment, such as the Arctic. In order to understand the protection mechanisms of psychrophilic bacteria against cold temperatures, we have explored a genome of KOPRI22215, tentatively identified as Psychromonas arctica, whose genome sequence has not yet been discovered. With an aim of searching for a coding gene of DnaK from KOPRI22215, we have applied a series of polymerase chain reactions (PCR) with homologous primers designed from other Psychromonas species and LA PCR in vitro cloning. 1917 bp complete coding sequence of dnaK from KOPRI22215 was identified including upstream promoter sites. Recombinant plasmids to overexpress PaDnaK along with EcDnaK (DnaK of E. coli) were then constructed in pAED4 vector and the pET-based system to induce PaDnaK expression by IPTG. Characterization assays of expressed PaDnaK were carried out by measuring survival rates upon 4 day incubation at 4 $^{\circ}C$: a refolding assay as molecular chaperone, and ATPase assay for functional activity. Taking account of all the data together, we conclude that PaDnaK was identified, successfully expressed, and found to be more efficient in providing cold-resistance for bacterial cells.

• Elastomers and Composites
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• v.46 no.2
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• pp.102-111
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• 2011

The innerliner for a tire has excellent impermeability, air retention and good flex properties. The innerliner offers a role to improve performance parameter, such as air retention and tire durability that is of praricular importance for commercial tires. In order to improve the gas barrier properties of a innerliner, most of the innerliner rubbers, such as a halogenated butyl rubber(HIIR), brominated poly(isobutylene-co-isoprene)(BIIR), brominated polyisobutylene-co-paramethylstyrene(BIMS) are used as nanocomposites with nano fillers such as silicates, graphite etc. Innerliners based on nanocomposites may allow gauge adjustments and permeability reductions with potential improvement in tire durability. This article discusses potential innerliner permeablity reduction and compounding parameters on the properties of nanocomposite based innerliners.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.5
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• pp.1943-1948
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• 2014

Purpose: The prevalence of weight loss in esophageal carcinoma patients is high and associated with impairment of physical function, increased psychological distress and low quality of life. It is not known which factors may contribute to weight loss in patients with esophageal carcinoma during radiotherapy in China. The objective of this study was to identify the associated demographic and clinical factors influencing weight loss. Methods: We evaluated 159 esophageal carcinoma patients between August 2010 and August 2013 in a crosssectional, descriptive study. Patient characteristics, tumor and treatment details, psychological status, adverse effects, and dietary intake were evaluated at baseline and during radiotherapy. A multivariate logistic regression analyss was performed to identify the potential factors leading to weight loss. Results: 64 (40.3%) patients had weight loss ${\geq}5%$ during radiotherapy. According to logistic regression analysis, depression, esophagitis, and loss of appetite were adverse factors linked to weight loss. Dietary counseling, early stage disease and total energy intake ${\geq}1441.3$ (kcal/d) were protective factors. Conclusions It was found that dietary counseling, TNM stage, total energy intake, depression, esophagitis, and loss of appetite were the most important factors for weight loss. The results underline the importance of maintaining energy intake and providing dietary advice in EC patients during RT. At the same time, by identifying associated factors, medical staff can provide appropriate medical care to reduce weight loss. Further studies should determine the effect of these factors on weight loss and propose a predictive model.

• BMB Reports
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• v.36 no.4
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• pp.409-416
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• 2003

The isoform 1 of cyclodextrin glycosyltransferase (CGTase, EC 2.4.1.19) from Paenibacillus sp. A11 was purified by a preparative gel electrophoresis. The importance of histidine, tryptophan, tyrosine, and carboxylic amino acids for isoform 1 activity is suggested by the modification of the isoform 1 with various group-specific reagents. Activity loss, when incubated with diethylpyrocarbonate (DEP), a histidine modifying reagent, could be protected by adding 25 mM methyl-$\beta$-cyclodextrin substrate prior to the modification. Inactivation kinetics of isoform 1 with DEP resulted in second-order rate constants ($k_{inactivation}$) of $29.5\;M^{-1}s^{-1}$. The specificity of the DEP-modified reaction for the histidine residue was shown by the correlation between the loss of isoform activity and the increase in the absorbance at 246 nm of N-carbethoxyhistidine. The number of histidines that were modified by DEP in the absence and presence of a protective substrate was estimated from the increase in the absorbance using a specific extinction coefficient of N-carbethoxyhistidine of $3,200\;M^{-1}cm^{-1}$. It was discovered that methyl-$\beta$-CD protected per mole of isoform 1, two histidine residues from the modification by DEP. To localize essential histidines, the native, the DEP-modified, and the protected forms of isoform 1 were digested by trypsin. The resulting peptides were separated by HPLC. The peptides of interest were those with $R_t$ 11.34 and 40.93 min. The molecular masses of the two peptides were 5,732 and 2,540 daltons, respectively. When the data from the peptide analysis were checked with the sequence of CGTase, then His-140 and His-327 were identified as essential histidines in the active site of isoform 1.

• Korean Management Science Review
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• v.22 no.2
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• pp.109-133
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• 2005

The exponential growth of the on-line shopping mall has been the advent of buying and selling products and services over the internet. In these circumstances, this paper presents the importance of understanding and managing the purchasing behavior of on-line shopping mall customers. The main purpose of this research is to find out the antecedents of customer trust and to conceptualize and investigate the relationship between endogenous mediating variables(such as customer trust, attitude, loyalty, relationship involvement) and purchasing and/or repurchasing intention in internet shopping mall. The empirical findings are as follows : First, the three antecedents of customer trust( EC system characteristics, psychological propensity, and trustworthiness) had the positive effects on the formation of site trust. Second, we found out that there were direct or indirect relationships between the mediating variables and on-line purchasing and/or repurchasing intention. In Particular, the direct effects of customer attitude on customer loyalty and buying intention were rejected, but the indirect effects through relationship involvement were accepted. This means that the relationship marketing is probably more important for the success of internet shopping mall Third, there were no direct relationship between the mediating variables and the repurchasing intention, but most researches in the brick and mortar, the proposition are supported. This implies that repurchasing intention was intensified by the indirect path, such as site trust $\longrightarroe$ attitude $\longrightarroe$ involvement $\longrightarroe$ loyalty $\longrightarroe$ purchasing intention $\longrightarroe$ repurchasing intention. So, the internet marketers must make an effort not only to strengthen the direct casual linkage between them but also to consolidate the indirect connections leading to boost purchasing and repurchasing intention.

• Molecules and Cells
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• v.26 no.3
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• pp.236-242
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• 2008

Invertase (${\beta}$-D-fructofuranosidase; EC 3.2.1.26) catalyzes the conversion of sucrose into glucose and fructose and is involved in an array of important processes, including phloem unloading, carbon partitioning, the response to pathogens, and the control of cell differentiation and development. Its importance may have caused the invertases to evolve into a multigene family whose members are regulated by a variety of different mechanisms, such as pH, sucrose levels, and inhibitor proteins. Although putative invertase inhibitors in the Arabidopsis genome are easy to locate, few studies have been conducted to elucidate their individual functions in vivo in plant growth and development because of their high redundancy. In this study we assessed the functional role of the putative invertase inhibitors in Arabidopsis by generating transgenic plants harboring a putative invertase inhibitor gene under the control of the CaMV35S promoter. A transgenic plant that expressed high levels of the putative invertase inhibitor transcript when grown under normal conditions was chosen for the current study. To our surprise, the stability of the invertase inhibitor transcripts was shown to be down-regulated by the phytohormone ABA (abscisic acid). It is well established that ABA enhances invertase activity in vivo but the underlying mechanisms are still poorly understood. Our results thus suggest that one way ABA regulates invertase activity is by down-regulating its inhibitor.

• Elastomers and Composites
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• v.55 no.2
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• pp.81-87
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• 2020

Service life prediction and evaluation of rubber components is the foundational technology necessary for securing the safety and reliability of the product and to ensure an optimum design. Even though the domestic industry has recognized the importance thereof, technology for a systematic design and analysis of the same has not yet been established. In order to develop this technology, identifying the fatigue damage parameters that affect service life is imperative. Most anti-vibration rubber components had been damaged by repeated load and aging. Hence, the evaluation of the fatigue characteristics is indispensable. Therefore, in this paper, we propose a method that can predict the service life of rubber components relatively accurately in a short period of time. This method works even in the initial designing stage. We followed the service life prediction procedure of the proposed rubber components. The weak part of the rubber and the maximum strain were analyzed using finite element analysis of the rubber bushing for the tracked vehicles. In order to predict the service life of the rubber components that were in storage for a certain period of time, the fatigue test was performed on the three-dimensional dumbbell specimen, based on the results obtained by the rubber material acceleration test. The service life formula of the rubber bushing for tracked vehicles was derived using both finite element analysis and the fatigue test. The service life of the rubber bushing for tracked vehicles was estimated to be about 1.7 million cycles at room temperature (initial stage) and about 400,000 cycles when kept in storage for 3 years. Through this paper, the service life for various rubber parts is expected be predicted and evaluated. This will contribute to improving the durability and reliability of rubber components.