• Journal of Life Science
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• v.33 no.12
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• pp.978-986
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• 2023

Inflammation by the innate immune system is a protective mechanism of the organism against infection-mediated environmental factors. It is also responsible for the pathogenesis of various human diseases, including the progression of cancer. Lichens are receiving increasing attention as a source of bioactive molecules with therapeutic potential for a variety of diseases. Additionally, the antioxidant, anti-inflammatory, and anticancer potential of lichen and its secondary metabolites have been widely reported. However, the underlying mechanism is still unknown. In the present study, to investigate molecular mechanisms of anti-inflammation and anti-cancer activity in the Antarctic lichen, Usnea aurantiaco-atra, methanol extract of Usnea aurantiaco-atra (MEUS) was used in vitro assays in RAW 264.7 macrophages cell and HCT116 colon cancer cells. Based on our data, MEUS had the anti-inflammatory activity through the modulation of main inflammatory indicators such as COX-2, IL-6, iNOS, TNF-α and NO production in a concentration-dependent manner. In addition, we observed that MEUS had cytotoxic activity against HCT116 colon cancer cells in a concentration-dependent manner, leading to a significantly reduced proliferation of the cancer cells through apoptotic induction by activating caspase-3. Taken together, this work firstly reported the anti-inflammatory and anti-cancer activities of an Antarctic lichen, Usnea aurantiaco-atra, and MEUS may provide a new insight into the molecular mechanisms underlying a link between inflammation and cancer.

• Korean Journal of Radiology
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• v.24 no.10
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• pp.974-982
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• 2023

Objective: Recent studies have highlighted the active and potential role of perivascular adipose tissue (PVAT) in atherosclerosis and aneurysm progression, respectively. This study explored the link between PVAT attenuation and abdominal aortic aneurysm (AAA) progression using computed tomography angiography (CTA). Materials and Methods: This multicenter retrospective study analyzed patients with AAA who underwent CTA at baseline and follow-up between March 2015 and July 2022. The following parameters were obtained: maximum diameter and total volume of the AAA, presence or absence of intraluminal thrombus (ILT), maximum diameter and volume of the ILT, and PVAT attenuation of the aortic aneurysm at baseline CTA. PVAT attenuation was divided into high (> -73.4 Hounsfield units [HU]) and low (≤ -73.4 HU). Patients who had or did not have AAA progression during the follow-up, defined as an increase in the aneurysm volume > 10 mL from baseline, were identified. Kaplan-Meier and multivariable Cox regression analyses were used to investigate the association between PVAT attenuation and AAA progression. Results: Our study included 167 participants (148 males; median age: 70.0 years; interquartile range: 63.0-76.0 years), of which 145 (86.8%) were diagnosed with AAA accompanied by ILT. Over a median period of 11.3 months (range: 6.0-85.0 months), AAA progression was observed in 67 patients (40.1%). Multivariable Cox regression analysis indicated that high baseline PVAT attenuation (adjusted hazard ratio [aHR] = 2.23; 95% confidence interval [CI], 1.16-4.32; P = 0.017) was independently associated with AAA progression. This association was demonstrated within the patients of AAA with ILT subcohort, where a high baseline PVAT attenuation (aHR = 2.23; 95% CI, 1.08-4.60; P = 0.030) was consistently independently associated with AAA progression. Conclusion: Elevated PVAT attenuation is independently associated with AAA progression, including patients of AAA with ILT, suggesting the potential of PVAT attenuation as a predictive imaging marker for AAA expansion.

• KDI Journal of Economic Policy
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• v.12 no.1
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• pp.127-148
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• 1990

A Milgrom-Roberts style signalling model of limit pricing is developed to analyze the possibility and the scope of limit pricing in general, noncooperative oligopolies. The model contains multiple incumbent firms facing a potential entrant and assumes an information asymmetry between incombents and the potential entrant about the market demand. There are two periods in the model. In period 1, n incumbent firms simultaneously and noncooperatively choose quantities. At the end of period 1, the potential entrant observes the market price and makes an entry decision. In period 2, depending on the entry decision of the entrant, n' or (n+1) firms choose quantities again before the game terminates. Since the choice of incumbent firms in period 1 depends on their information about demand, the market price in period 1 conveys information about the market demand. Thus, there is a systematic link between the market price and the profitability of entry. Using Bayes-Nash equilibrium as the solution concept, we find that there exist some demand conditions under which incumbent firms will limit price. In symmetric equilibria, incumbent firms each produce an output that is greater than the Cournot output and induce a price that is below the Cournot price. In doing so, each incumbent firm refrains from maximizing short-run profit and supplies a public good that is entry deterrence. The reason that entry is deterred by such a reduced price is that it conveys information about the demand of the industry that is unfavorable to the entrant. This establishes the possibility of limit pricing by noncooperative oligopolists in a setting that is fully rational, and also generalizes the result of Milgrom and Roberts to general oligopolies, confirming Bain's intuition. Limit pricing by incumbents explained above can be interpreted as a form of credible collusion in which each firm voluntarily deviates from myopic optimization in order to deter entry using their superior information. This type of implicit collusion differs from Folk-theorem type collusions in many ways and suggests that a collusion can be a credible one even in finite games as long as there is information asymmetry. Another important result is that as the number of incumbent firms approaches infinity, or as the industry approaches a competitive one, the probability that limit pricing occurs converges to zero and the probability of entry converges to that under complete information. This limit result confirms the intuition that as the number of agents sharing the same private information increases, the value of the private information decreases, and the probability that the information gets revealed increases. This limit result also supports the conventional belief that there is no entry problem in a competitive market. Considering the fact that limit pricing is generally believed to occur at an early stage of an industry and the fact that many industries in Korea are oligopolies in their infant stages, the theoretical results of this paper suggest that we should pay attention to the possibility of implicit collusion by incumbent firms aimed at deterring new entry using superior information. The long-term loss to the Korean economy from limit pricing can be very large if the industry in question is a part of the world market and the domestic potential entrant whose entry is deterred could .have developed into a competitor in the world market. In this case, the long-term loss to the Korean economy should include the lost opportunity in the world market in addition to the domestic long-run welfare loss.

• Journal of Intelligence and Information Systems
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• v.23 no.4
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• pp.111-126
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• 2017

Recommender systems based on association rule mining significantly contribute to seller's sales by reducing consumers' time to search for products that they want. Recommendations based on the frequency of transactions such as orders can effectively screen out the products that are statistically marketable among multiple products. A product with a high possibility of sales, however, can be omitted from the recommendation if it records insufficient number of transactions at the beginning of the sale. Products missing from the associated recommendations may lose the chance of exposure to consumers, which leads to a decline in the number of transactions. In turn, diminished transactions may create a vicious circle of lost opportunity to be recommended. Thus, initial sales are likely to remain stagnant for a certain period of time. Products that are susceptible to fashion or seasonality, such as clothing, may be greatly affected. This study was aimed at expanding association rules to include into the list of recommendations those products whose initial trading frequency of transactions is low despite the possibility of high sales. The particular purpose is to predict the strength of the direct connection of two unconnected items through the properties of the paths located between them. An association between two items revealed in transactions can be interpreted as the interaction between them, which can be expressed as a link in a social network whose nodes are items. The first step calculates the centralities of the nodes in the middle of the paths that indirectly connect the two nodes without direct connection. The next step identifies the number of the paths and the shortest among them. These extracts are used as independent variables in the regression analysis to predict future connection strength between the nodes. The strength of the connection between the two nodes of the model, which is defined by the number of nodes between the two nodes, is measured after a certain period of time. The regression analysis results confirm that the number of paths between the two products, the distance of the shortest path, and the number of neighboring items connected to the products are significantly related to their potential strength. This study used actual order transaction data collected for three months from February to April in 2016 from an online commerce company. To reduce the complexity of analytics as the scale of the network grows, the analysis was performed only on miscellaneous goods. Two consecutively purchased items were chosen from each customer's transactions to obtain a pair of antecedent and consequent, which secures a link needed for constituting a social network. The direction of the link was determined in the order in which the goods were purchased. Except for the last ten days of the data collection period, the social network of associated items was built for the extraction of independent variables. The model predicts the number of links to be connected in the next ten days from the explanatory variables. Of the 5,711 previously unconnected links, 611 were newly connected for the last ten days. Through experiments, the proposed model demonstrated excellent predictions. Of the 571 links that the proposed model predicts, 269 were confirmed to have been connected. This is 4.4 times more than the average of 61, which can be found without any prediction model. This study is expected to be useful regarding industries whose new products launch quickly with short life cycles, since their exposure time is critical. Also, it can be used to detect diseases that are rarely found in the early stages of medical treatment because of the low incidence of outbreaks. Since the complexity of the social networking analysis is sensitive to the number of nodes and links that make up the network, this study was conducted in a particular category of miscellaneous goods. Future research should consider that this condition may limit the opportunity to detect unexpected associations between products belonging to different categories of classification.

• Journal of the Korean Regional Science Association
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• v.9 no.1
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• pp.65-78
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• 1993

In this study, the significant and enduring concentration of federal R&D spending in metro-scale clusters across the nation is treated as evidence of the operation of a distinct industrial infrastructure defined by the ability of R&D performers to attract external funding and pursue the sophisticated project work demanded. It follows, then, that the agglomerative potential of these R&D concentrations -- performers and their support infrastructures -- requires a search for economic impacts guided by a different stimulative effects attributable to federal R&D spending may be that substantial subnational economic impacts are routinely obscured and diluted by research designs that seek to discover impacts either at the level of nation-scale economic aggregates or on firms or specific industries organized spatially. Therefore, this study proceeds by seeking to link the locational clustering of federal contract R&D spending to more localized economic impacts. It tests a series of models(X-IV) designed to trace federal contract R&D spending flows to economic impacts registered at the level of metro-regional economies. By shifting the focus from funding sources to recipient types and then to sector-specific impacts, the patterns of consistent results become increasingly compelling. In general, these results indicated that federal R&D spending does indeed nurture the development of an important nation-spanning advanced industrial production and R&D infrastructure anchored primarily by two dozed or so metro-regions. However, dominated as it is by a strong defense-industrial orientation, federal contract R&D spending would appear to constitute a relatively inefficient national economic development policy, at least as registered on conventional indicators. Federal contract R&D destined for the support of nondefense/civilian(Model I), nonprofit(Model II), and educational/research(Mode III) R&D agendas is associated with substantially greater regional employment and income impacts than is R&D funding disbursed by the Department of Defense. While federal R&D support from DOD(Model I) and for-profit(Model II) and industrial performer(Model III) contract R&D agendas are associated with positive regional economic impacts, they are substantially smaller than those associated with performers operating outside the defense industrial base. Moreover, evidence that the large-business sector mediates a small business sector(Model VI) justifies closer scrutiny of the relative contribution to economic growth and development made by these two sectors, as well as of the primacy typically accorded employment change as a conventional economic performance indicator. Ultimately, those regions receiving federal R&D spending have experienced measurable employment and income gains as a result. However, whether or not those gains could be improved by changing the composition -- and therefore the primary missions -- of federal R&D spending cannot be decided by merely citing evidence of its economic impacts of the kind reported here. Rather, that decision turns on a prior public choice relating to the trade-offs deemed acceptable between conventional employment and income gains, the strength of a nation's industrial base not reflected in such indicators, and the reigning conception of what constitutes national security -- military might or a competitive civilian economy.

• Journal of Korea Water Resources Association
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• v.45 no.2
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• pp.203-215
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• 2012

The objective of this study is to develop a catchment hydrologic cycle assessment model which can assess the impact of urban development and designing water cycle improvement facilities. Developed model might contribute to minimize the damage caused by urban development and to establish sustainableurban environments. The existing conceptual lumped models have a potential limitation in their capacity to simulate the hydrologic impacts of land use changes and assess diverse urban design. The distributed physics-based models under active study are data demanding; and much time is required to gather and check input data; and the cost of setting up a simulation and computational demand are required. The Catchment Hydrologic Cycle Assessment Tool (hereinafter the CAT) is a water cycle analysis model based on physical parameters and it has a link-node model structure. The CAT model can assess the characteristics of the short/long-term changes in water cycles before and after urbanization in the catchment. It supports the effective design of water cycle improvement facilities by supplementing the strengths and weaknesses of existing conceptual parameter-based lumped hydrologic models and physical parameter-based distributed hydrologic models. the model was applied to Seolma-cheon catchment, also calibrated and validated using 6 years (2002~2007) hourly streamflow data in Jeonjeokbigyo station, and the Nash-Sutcliffe model efficiencies were 0.75 (2002~2004) and 0.89 (2005~2007).

• The Journal of Society for e-Business Studies
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• v.20 no.4
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• pp.193-208
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• 2015

In knowledge based society, information technology (IT) has been playing a key role in economic growth. In recent years, it is surprisingly notable that the source of value creation moved from hardware to software in IT industry. Especially, among many kinds of software products, the economic potential of open source was realized by many government agencies. Open source means software codes made by voluntary and open participation of worldwide IT developers, and many policies to promote open source activities were implemented for the purpose of fast growth in IT industry. But in many cases, especially in Korea, the policies promoting open source industry and its ecosystem were not considered successful. Therefore, this study provides the practical reasons for the low performance of Korean open source industry and suggests the pragmatic requisites for effective open source policy. For this purpose, this study applies soft system model (SSM) which is frequently used in academy and industry as a methodology for problem-solving and we link the problems with corresponding policy solutions based on SSM. Given concerns which Korean open source faces now, this study suggests needs for the three different kinds of government policies promoting multiple dimensions of industry: research and development (R&D)-side, supply-side, and computing environment-side. The implications suggested by this research will contribute to implement the practical policy solutions to boost open source industry in Korea.

• Journal of Ginseng Research
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• v.39 no.3
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• pp.230-237
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• 2015

Background: Colorectal cancer (CRC) is a leading cause of death worldwide. Chronic gut inflammation is recognized as a risk factor for tumor development, including CRC. American ginseng is a very commonly used ginseng species in the West. Methods: A genetically engineered $Apc^{Min/+}$ mouse model was used in this study. We analyzed the saponin composition of American ginseng used in this project, and evaluated its effects on the progression of high-fat-diet-enhanced CRC carcinogenesis. Results: After oral ginseng administration (10-20 mg/kg/d for up to 32 wk), experimental data showed that, compared with the untreated mice, ginseng very significantly reduced tumor initiation and progression in both the small intestine (including the proximal end, middle end, and distal end) and the colon (all p < 0.01). This tumor number reduction was more obvious in those mice treated with a low dose of ginseng. The tumor multiplicity data were supported by body weight changes and gut tissue histology examinations. In addition, quantitative real-time polymerase chain reaction analysis showed that compared with the untreated group, ginseng very significantly reduced the gene expression of inflammatory cytokines, including interleukin-$1{\alpha}$ (IL-$1{\alpha}$), IL-$1{\beta}$, IL-6, tumor necrosis factor-${\alpha}$, granulocyte-colony stimulating factor, and granulocyte-macrophage colony-stimulating factor in both the small intestine and the colon (all p < 0.01). Conclusion: Further studies are needed to link our observed effects to the actions of the gut microbiome in converting the parent ginsenosides to bioactive ginseng metabolites. Our data suggest that American ginseng may have potential value in CRC chemoprevention.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.148-153
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• 1993

Composition and structure of synthetic glucitol fatty acid polyesters (GPE)-a potential fat substitute-were investigated. Also degree of substitution (D.S) of GPE was determined according to the relative ester distribution within it to evaluate the feasibility of GPE using as a fat substitute. The GPE was separated into single ester group by a normal-phase HPLC and D.S of it was identified to be 6. Absorption band at $1747\;cm^{-1}$ in the IR spectrum of GPE indicated that there were ester bonds within GPE molecules. which link fatty acid moiety to glucitol. Disappearance of the hydroxyl proton signals of glucitol in the H-NMR spectrum of GPE implied that most of hydroxyl groups in glucitol participated in the formation of ester bonds with fatty acids. In addition the D.S estimated from the quantitative proton integration of GPE coincided well with the D.S of GPE determined by hydroxyl value measurement. In conclusion, the GPE synthesized in this study was found to be a glucitol fatty acid hexaester so that it is expected to be used as a fat substitute in the near future.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.4
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• pp.1055-1060
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• 2004

Apoptosis is the ability of cells to self-destruct by the activation of an intrinsic cellular suicide program when the cells are no longer needed or when they are seriously damaged. Morphologically, apoptosis is characterized by the appearance of membrane blebbing, cell shrinkage, chromatin condensation, DNA cleavage, and the fragmentation of the cell membrane-bound apoptotic bodies. Siegesbeckia glabrescens Makino (Siegesbeckiae Herba, SG) has been widely used as treatments for arthritis, and fever, as well as detoxification properties. The present studies were undertaken to evaluate if SG has an anti-apoptotic property. Cell viability was measured by XTT and tryphan blue stain. Morphological characteristic of human aortic smooth muscle cells(HASMC) were visualized with a phase-contrast microscope. SG significantly reduced HASMC, but not human umbilical vein endothelial cell(HUVEC), viability in a dose-dependent manner. Confluent untreated cells at 24hrs showed normal morphology, flat with a uniform polygonal shape. SG-treated cells (0.5㎎/㎖) at 24hrs showed apoptotic morphology. Cells became irregular with elongated lamellipodia, and exhibited condensed chromatin in nuclei with occasional endoucleation. There was an increase in the number of apoptotic cells rounding-up and being detached from the substrate. TUNEL staining of SG-treated cells showed dark-brown stains in nuclei and cytosol. Caspases are central components of the machinery responsible for apoptosis and are generally divided into two categories; the initiator caspases, which include caspases-2,-8,-9, and -10, and the effector caspases, which include caspases-3,-6, and -7. SG decreased anti-caspase-3 protein expression, which means activation of caspases-3 activity. It has been reported that there is a link between NO formation and apoptosis. NO production was accelerated by SG treatment in HASMC. L-NNA, NOS inhibitor, inhibited SG-induced apoptosis. These results, therefore, indicated that both caspases-3 and NO production are involved in apoptosis in smooth muscle cells. According to these results, SG may have a potential effect in the treatment of hypertensive atherosclerosis.