• Journal of Ecology and Environment
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• v.36 no.1
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• pp.73-83
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• 2013

The object of this study was to evaluate lotic ecosystem health using multiple eco-metric approaches such as water chemistry diagnosis, physical habitat health evaluations, and biological integrity modeling at 100 streams of four major watersheds. For the study, eight chemical water quality parameters such as nutrients (N, P) and organic material were measured and 11-metric models of Qualitative Habitat Evaluation Index (QHEI) and multiple eco-metric health assessment model (MEHA) were applied to the four major watershed. Nutrient analysis of nitrogen (N) and phosphorus (P) in all watersheds indicated a eutrophic state depending on the locations of sampling streams. Physical habitat health, based on the QHEI model, averaged 114 (range: 56 - 194), judging as a "good condition" by the criteria of Plafkin et al. (1989). In addition, primary (H1 - H4), secondary (H5 - H7), and tertiary habitat metric variables (H8 - H11) were analyzed in relation to the physical habitat degradations. The plots of tolerant species ($P_{TS}$) and sensitive species ($P_{SS}$) to water quality showed that the proportions of $P_{TS}$ had positive linear functions with nutrients, and that the $P_{SS}$ had inverse linear relations with the chemical variables. The model of eco-metric health assessment showed that mean MEHA was 20.4, indicating a fair condition. Overall, our data suggest that water chemistry, based on nutrients and organic matter, directly modified the trophic structures in relation to food chain in the aquatic ecosystems, and then these directly influenced the compositions of tolerance/sensitive species, resulting in degradations of overall ecological health.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.655-660
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• 2022

This paper analyzes the problem of the economic order quantity (lot size) of a retailer in a two-stage supply chain consisting of a supplier, a retailer(distributor), and a customer. In this two-stage supply chain, the supplier permits the retailer to defer payment for a certain fixed period of time for the purchase cost to be paid by the retailer as a price differentiation strategy with his competitor. In addition, in the case of customer goods such as food and grain, it is common to see that end-customer demand is generally depend on the level of inventory displayed by the retailer. From this perspective, this paper analyzes the inventory problem of retailers under the assumption that the supplier may allow a certain period to suspend payments for the purchase of goods and the end customer demand is a function of the retailer's inventory level increasing with size. In this regard, we need to analyze how much the length of the grace period for product purchase costs affect the retailer's lot-sizing policy. Therefore, we formulate the retailer's annual net profit and analyze the effect of the length of credit period on the retailer's inventory policy numerically.

• Korean Journal of Plant Resources
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• v.32 no.6
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• pp.633-643
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• 2019

Long-term ultraviolet (UV) exposure accelerates the phenomenon of skin photo-aging by activating collagenase and elastase. In this study, we aimed to investigate the effects of a combination of grapefruit and rosemary extracts (cG&Re) on UVB-irradiated damage in HaCaT cells and dorsal mouse skin. In HaCaT cells, cG&Re recovered UVB-reduced cell viability and inhibited protein expression of mitogen-activated protein kinases (MAPKs), such as extracellular signal-regulated kinases (p-Erk), c-Jun N-terminal kinases (p-JNK), and a class of MAPKs (p-P38). Also, cG&Re suppressed UVB-induced collagen and elastin degradation by decreasing matrix metalloproteinases (MMPs) and nuclear factor kappa light chain enhancer of activated B cells (NF-κB) expression, which is a transcription factor. Similar results were observed in dorsal mouse skin. Taken together, our data indicate that cG&Re prevent UVB-induced skin photo-aging due to collagen/elastin degradation via activation of MAPKs, MMPs, and the NF-κB signaling pathway in vitro and in vivo.

• Journal of Microbiology and Biotechnology
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• v.25 no.7
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• pp.1084-1092
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• 2015

In the present work, the in vitro prebiotic activity of xylooligosaccharides (XOS) derived from corn cobs combined with Lactobacillus plantarum, a probiotic microorganism, was determined. These probiotics exhibited different growth characteristics depending on strain specificity. L. plantarum S2 cells were denser and their growth rates were higher when cultured on XOS. Acetate was found to be the major short-chain fatty acid produced as the end-product of fermentation, and its amount varied from 1.50 to 1.78 mg/ml. The antimicrobial activity of XOS combined with L. plantarum S2 was determined against gastrointestinal pathogens. The results showed that XOS proved to be an effective substrate, enhancing antimicrobial activity for L. plantarum S2. In vivo evaluation of the influence of XOS and L. plantarum S2, used both alone and together, on the intestinal microbiota in a mouse model showed that XOS combined with L. plantarum S2 could increase the viable lactobacilli and bifidobacteria in mice feces and decrease the viable Enterococcus, Enterobacter, and Clostridia spp. Furthermore, in the in vitro antioxidant assay, XOS combined with L. plantarum S2 possessed significant 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis, and superoxide anion radical-scavenging activities, and the combinations showed better antioxidant activity than either XOS or L. plantarum S2 alone.

• Journal of Korean Society of Transportation
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• v.30 no.3
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• pp.107-118
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• 2012

The purpose of the study is to analyze the travel characteristics of freight trucks in metropolitan areas, focusing on activity generation, destination choice, and trip chaining behaviors. The results showed that the number of service companies at departure areas has a primary influence on the activity generation pattern and destination choice behavior of trucks in metropolitan areas. The number of trips within a trip chain is largest, in case where the prevailing industry in destination areas is wholesale or retail and the shipment item is food or beverage. These results imply that for the reasonable estimation of truck travel demand both the trip chaining behaviors and the industrial compositions in departure and destination areas should be separately considered for each type of commodity.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.747-759
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• 2011

The purpose of this study was to compare the trophic structures and the energy flows in the Lake Namyang and the lower reaches of the Nakdong River using the Ecopath model. The sampling and analyses were carried out at 6 sampling sites of the Lake Namyang and the lower reaches of the Nakdong River respectively on March and November in 2007. As a result, the Lake Namyang was consisted of producers(Detritus, Macrophytes, Phytoplankton), primary consumers(Zooplankton, Zoobenthos, Carassius cuvieri, Carassius auratus, Other fishes) and secondary consumer(Cyprinus carpio, Pseudobagrus fulvidraco) and the lower reaches of the Nakdong River was consisted of producers(Detritus, Macrophytes, Phytoplankton), primary consumers (Zooplankton, Zoobenthos, Cyprinus carpio, Hemibarbus labeo, Other fishes) and secondary consumer (Micropterus salmoides). The food-chain length of the Lake Namyang was relatively short when compared with the lower reaches of the Nakdong River. The shortness of food-chain length in the Lake Namyang could be attributed to the low biomass of the top predators. The total system throughput of the lake Namyang was estimated at 14.3 kg $m^{-2}\;year^{-1}$ including a consumption of 39.0%, exports of 21.0%, respiratory flows of 12.0% and flows into detritus of 28.0% and the total system throughput of the lower reaches of the Nakdong River was estimated at 2.8 kg $m^{-2}\;year^{-1}$ including a consumption of 52.0%, exports of 9.1%, respiratory flows of 18.0% and flows into detritus of 20.9% in the lower reaches of the Nakdong River.

• Korean Journal of Agricultural Science
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• v.18 no.2
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• pp.148-156
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• 1991

This study was carried out to investigate the storage conditions and methods required for commercialization of Jeung-Pyon. The storage characteristics of Jeung-Pyon were examined with Universal Testing Machine (UTM, Instron model 1000) for textural properties during storage of under the conditions such as sealing, nonsealing, and temperatures. The differences in storage characteristics on the different varieties and years of rices were not shown. When the Jeung-Pyon was lost it's quality as a commercial product, the measured value of UTM was increased as hardness 0.74Kg to 1.0Kg, gumminess 0.23Kg to 0.59Kg, chewiness 6Kg.mm to 18Kg.mm, but decreased in adhesiveness 0.65Kg.mm to 0.40Kg.mm, cohesiveness 0.61 to 0.34, springiness 41mm to 32mm. The nonsealed Jeung-Pyon was lost it's quality for storing at room temperature because of the case-hardening after 2 days. In the case of sealed Jeung-Pyon, the case-hardening phenomena by the evaporation of moisture was not occured, therefore it was a significant factor for an extension in sealed Jeung-Pyon. The shelf-life of sealed Jeung-Pyon was 20 days and 5 days respectively during storage at $-20^{\circ}C$ and $20^{\circ}C$. The sealed Jeung-Pyon stored at $5^{\circ}C$ was lost it's quality, in consideration of cold chain this temperature was suitable for retrogradation of starch. The Jeung-Pyon sealed with air and mosture proof packaging material stored at the accelerated condition as 92% R.H. and $35^{\circ}C$ lost it's quality within two or three days.

• Journal of Food Hygiene and Safety
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• v.29 no.1
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• pp.31-39
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• 2014

Norovirus causes acute gastroenteritis in all age groups and its food poisoning outbreaks are rapidly increasing in Korea. Reverse transcription-polymerase chain reaction (RT-PCR) is most widely used for the rapid detection of foodborne viruses due to high sensitivity. However, the false positive results of RT-PCR obtained against already inactivated viruses could be a serious drawbacks in food safety area. In this study, we investigated a method to yield true positive RT-PCR results only with alive viruses. To decompose the RNA genes from dead viruses, the enzymatic treatments composed of proteinse K and Ribonuclease A were applied to the sanitized and inactivated virus particles. Another aim of this study was to quantify the efficiencies of several major sanitizing treatments using real-time RT-PCR. Feline calicivirus (FCV) that belongs to the same Caliciviridae family with norovirus was used as a surrogate model for norovirus. The initial level of virus in control suspension was approximately $10^4$ PFU/mL. Most of inactivated viruses treated with the enzymatic treatment for 30 min at $37^{\circ}C$ were not detected in RT-PCR, Quantification results to verify the inactivation efficiencies of sanitizing treatments using real-time RT-PCR showed no false positive in most cases. We could successfully develope a numerical quantification process for the inactivated viruses after major sanitizing treatments using real-time RT-PCR. The results obtained in this study could provide a novel basis of rapid virus quantification in food safety area.

• Journal of Distribution Science
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• v.18 no.5
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• pp.89-98
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• 2020

Purpose: The growth of online commerce is now becoming a major threat and a new opportunity for retailers. Existing offline retailers struggle to cope with new online retailers' threats by utilizing offline infrastructure. Besides, online retailers expand their online strengths to offline sales by opening their offline stores. Many retailers are paying close attention to the O2O business and the resulting changes. Thus, this research focuses on the O2O business model and process that retailers can adopt. Research design, data and methodology: Considering the features of products that retailers sell, this paper divides O2O business process with the following criteria: delivery lead-time and delivery area. And This research uses the business model canvas to define the features of O2O commerce business process. This paper also uses nine key elements in the business model canvas for analyzing the structure of O2O commerce business. Results: This paper suggests the delivery model of retailers respond to offline customer orders and summarizes the following results. (1) Considering characteristics such as logistics process, delivery area, and product type, we define the features of O2O business models: wide-area (warehouse) based O2O business model, regional area (store) based O2O business model and time-separated O2O business model. (2) This study checks the availability of the business model through the business cases of O2O business models. (3) This study also analyzes the O2O business model of domestic retail companies by the factors defined in the business model canvas. Conclusions: Retailers can adopt the O2O business process to fit their business requirements and strategy. The online retailers who deal with normal consumer products mainly have the wide-area based O2O business model. The wide-area based O2O business model can be suitable for retailers who manage inventory centrally. The time-separated O2O business model can be a good solution for fresh food retailers to operate the logistics process efficiently. And to shorten the delivery lead-time of fresh foods, the regional area based O2O business model can be fit to the retailer that utilizes its offline logistics or sales infrastructure. It may be much more important for retailers to share the inventory information with other branches and to change the role of offline stores.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.934-939
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• 2001

The growth inhibition of Campylobacter jejuni ATCC 33291 in the presence of $1\%$ acetic acid at 4, 25, and $42^{\circ}C$, followed by $25^{\circ}C$ and $4^{\circ}C$, at pH 5.5 and pH 6.5, and by the addition of $1\%$ acetic acid aat 4, 25, and $42^{\circ}C$ were determined to be 22, 8.5, and 1.4 min, respectively, in an FBP-SBB medium. The D values of C. jejuni were increased by the addition of chicken and did not follow the linear relationship observed in the FBP-SBB media without chicken. When using distilled water instead of FBP-SBB in the model system, the death rate of C. jejuni was dramatically accelerated. The injured or low cell numbers that were impossible to enumerate using the plate count method, were detected by a polymerase chain reaction and enrichment culture procedure. These results suggested that acetic acid is reliable and effective as a disinfectant, however, it is necessary to take additional care at refrigeration temperatures due to the potential of injred cells during poultry processing.