• IMMUNE NETWORK
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• 제16권3호
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• pp.165-175
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• 2016

Ambroxol is used in COPD and asthma to increase mucociliary clearance and regulate surfactant levels, perhaps through anti-oxidant and anti-inflammatory activities. To determine the role and effect of ambroxol in an experimental model of asthma, BALB/c mice were sensitized to ovalbumin (OVA) followed by 3 days of challenge. Airway hyperresponsiveness (AHR), lung cell composition and histology, and cytokine and protein carbonyl levels in bronchoalveolar lavage (BAL) fluid were determined. Ambroxol was administered either before the first OVA challenge or was begun after the last allergen challenge. Cytokine production levels from lung mononuclear cells (Lung MNCs) or alveolar macrophages (AM) were also determined. Administration of ambroxol prior to challenge suppressed AHR, airway eosinophilia, goblet cell metaplasia, and reduced inflammation in subepithelial regions. When given after challenge, AHR was suppressed but without effects on eosinophil numbers. Levels of IL-5 and IL-13 in BAL fluid were decreased when the drug was given prior to challenge; when given after challenge, increased levels of IL-10 and IL-12 were detected. Decreased levels of protein carbonyls were detected in BAL fluid following ambroxol treatment after challenge. In vitro, ambroxol increased levels of IL-10, IFN-γ, and IL-12 from Lung MNCs and AM, whereas IL-4, IL-5, and IL-13 production was not altered. Taken together, ambroxol was effective in preventing AHR and airway inflammation through upregulation of Th1 cytokines and protection from oxidative stress in the airways.

• IMMUNE NETWORK
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• 제5권2호
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• pp.68-77
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• 2005

Background: Costimulation is a critical process in Ag-specific immune responses. Both B7.1 and CD28 molecules have been reported to stimulate T cell responses during antigen presentation. Therefore, we tested whether Ag-specific immune responses as well as protective immunity are influenced by coinjecting with B7.1 and CD28 cDNAs in a mouse HSV-2 challenge model system. Methods: ELISA was used to detect levels of antibodies, cytokines and chemokines while thymidine incorporation assay was used to evaluate T cell proliferation levels. Results: Ag-specific antibody responses were enhanced by CD28 coinjection but not by B7.1 coinjection. Furthermore, CD28 coinjection increased IgG1 production to a significant level, as compared to pgD+pcDNA3, suggesting that CD28 drives Th2 type responses. In contrast, B7.1 coinjection showed the opposite, suggesting a Th1 bias. B7.1 coinjection also enhanced Ag-specific Th cell proliferative responses as well as production of Th1 type cytokines and chemokines significantly higher than pgD+pcDNA3. However, CD28 coinjection decreased Ag-specific Th cell proliferative responses as well as production of Th1 types of cytokines and chemokine significantly lower than pgD+pcDNA3. Only MCP-1 production was enhanced by CD28. B7.1 coimmunized animals exhibited an enhanced survival rate as well as decreased herpetic lesion formation, as compared to pgD+pcDNA3. In contrast, CD28 vaccinated animals exhibited decreased survival from lethal challenge. Conclusion: This study shows that B7.1 enhances protective Th1 type cellular immunity against HSV-2 challenge while CD28 drives a more detrimental Th2 type immunity against HSV-2 challenge, supporting an opposite role of B7.1 and CD28 in Ag-specific immune responses to a Th1 vs Th2 type.

• 대한바이러스학회지
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• 제26권1호
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• pp.67-76
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• 1996

The methods that make Hantavirus grow consist of inoculation into the experimental animals and cultured cells. The cultured cells, such as Vero-E6 and A549 cells, have been usually used for isolation of the virus and the animals, such as mice and rats, are used for large scale preparation of the virus so far. Furthermore, the cell can be used to maintain the virus and assay the infectivity and the animals can be used for the experiment of viral pathogenicity and challenge for assessment of vaccine. Apodemus mice, the own natural host of the virus, has been used for challenge test of Hantaan virus. However it has been pointed out to difficult handling and breeding the animal in laboratory. Therefore, we attempted to establish a new animal model for challenge test at the time of isolation of Maaji virus which is a new hantavirus similar but distinct to Hantaan virus. In suckling hamster, the titer of Maaji virus and the lethality to mice of the virus were increased gradually in the titer and lethality through passage by intracerebral (IC) inoculation. We tried to re-adapt this brain virus to lung of weanling hamster. The brain passaged virus was inoculated into weanling hamster intramuscularly. Again, the titer of the virus in lung was also increased by continuous passage of this virus. This facts could regarded as adaptation to new environment in which the virus proliferates. To identity the virus passaged in hamster with Maaji virus, both of the virus passaged in hamster brain and lung were compared with Maaji virus (MAA-I) and Hantaan virus (HTN 76-118) by means of restriction fragment length polymorphism (RFLP) and slingle strand conformation polymophism (SSCP). As a result, we conclude that Maaji virus could be adapted successfully to weanling hamster through this passage strategy. Utilizing this adapted Maaji virus strain, hamster model is able to be used for challenge test in hantaviral vaccinology and further experiments utilizing hamster system as a rather available and convenient lab animal are expected.

• 농업과학연구
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• 제43권5호
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• pp.788-793
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• 2016

Post-weaning diarrhea (PWD), mostly caused by enterotoxigenic Escherichia coli (ETEC), remains to be a major source of economic loss in swine industry. The use of the ETEC-oral challenge model is often applied to mimic unsanitary commercial swine farm conditions where pathogens and unknown complex microbes exist and can cause severe infections in pigs. The purpose of this study was (1) to estimate ETEC density using spectrophotometric computation, (2) to determine survivability of ETEC after storing at $-20^{\circ}C$ for 7 days, and (3) to evaluate survivability of ETEC after blending with diluted sweeteners (0, 5, 10, 20, and 40% sucrose in phosphate buffered saline [PBS]). Cell density was quantified using UV-VIS spectrophotometer and counting ETEC colony forming units (cfu) at 0, 30, 60, 90, 120, 150, 180, 210, and 240 min. The established linear equation ($y=0.0031x^2-0.0079x+0.0043$ and $y=0.0046x^2-0.0151x+0.0113$) was used for robust quantification of each ETEC cell density. ETEC stored at $-20^{\circ}C$ showed 108 cfu/mL after thawing and incubation. When ETEC was blended with sweeteners (20 and 40%), survival of ETEC was decreased by 58 and 54% in 5 min post blending. However, addition of 20% of sweetener resulted in a higher survivability than those with other media concentrations. Therefore, the use of ETEC-oral challenge model would be possible as a stable method if we could confirm the appropriate medium that increases survivability of ETEC in weaner pigs.

• Journal of Information Technology Applications and Management
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• 제27권6호
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• pp.197-224
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• 2020

Mobile games have become one of the most important driving forces of the game industry. We focus on the continuous intention to use Chinese mobile games from the perspective of experiential marketing and network externalities. We integrate user experience, network externalities and flow theory into expectation confirmation model and explore the influencing factors of continuous usage intention of Chinese mobile game and propose a research model. Game experience, service experience, perceived enjoyment, social interaction, challenge, perceived number of users and perceived number of peers were employed as independent variables, while flow, perceived value and satisfaction as mediating variables and continuous intention as the dependent variable. After surveying 426 samples, the model is tested with structural equation model. The results reveal that perceived enjoyment significantly positively influences perceived value, flow, satisfaction, and continuous intention. The greater the enjoyment of the game, the greater the satisfaction of the game and the greater the willingness to use it continuously. Game experience has a significant direct effect on continuous intention, which indicates that a better game experience can retain more users. Service experience and perceive number of peers positively influence satisfaction. Another finding is that social interaction and perceived number of users positively influence perceived value and flow, which indicate that social attributes are critical roles for retaining users. Game challenge also positively influences flow. The proper level of challenge is more likely to cause users to enter the state of flow. Flow indirectly influences continuous usage intention through the satisfaction of the game, which indicates that satisfaction is driven by flow experience and further retaining users. Empirical results implied that mobile game companies need to focus on improving user experience, expectation satisfaction and extending network externalities to improve the continuous intention of using mobile game.

• 한국HCI학회논문지
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• 제13권3호
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• pp.5-15
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• 2018

소셜네트워크게임(Social Network Game, 이하 SNG)의 가장 큰 특징은 SNS의 사회관계망을 바탕으로 실제로 알고 있는 지인들과의 경쟁과 협력을 통해 게임플레이가 진행된다는 점에 있다. 그러나 기존 게임분야 연구에서 경쟁과 도전감이 게임 몰입 등에 영향을 미치는 선행요인으로써 중요하게 다루어져 왔음에도 불구하고 SNG에서 이루어지는 지인 간 순위경쟁의 특성을 고려한 깊이 있는 연구는 부족한 실정이다. 더불어 SNG에서는 지인들이 경쟁의 대상인 동시에 도전의 대상이 될 수 있다는 점을 고려하지 못하였다. 따라서 본 연구에서는 SNS의 사회관계망을 기반으로 하는 모바일 퍼즐 SNG의 지인 간 순위경쟁 특성을 사회비교이론의 자기평가유지모형 선행연구를 통해 분석하여 경쟁심과 도전감에 영향을 미치는 요인으로써 비교대상의 성취정도 (큰 순위차이, 작은 순위차이), 비교대상과의 친밀감 (강한 유대관계, 약한 유대관계)의 두 요인을 규명하고 이러한 요인 및 요인 간 상호작용이 순위경쟁상황에서 플레이어의 경쟁심과 도전감에 어떠한 영향을 미치는지를 실증적으로 분석하였다. 결과적으로 순위차이가 큰 경쟁대상보다 순위차이가 비교적 작은 경쟁대상을 우선적으로 노출시킬 때, 더불어 유대관계가 약한 경쟁대상보다 유대관계가 강한 경쟁대상을 우선적으로 노출시킬 때 플레이어의 경쟁심을 자극하여 도전감을 향상시킬 수 있음을 알 수 있었다. 이와 같은 연구결과는 SNG 순위표 콘텐츠 디자인의 실무에 있어 그 활용 가치가 클 것으로 기대할 수 있다.

• Toxicological Research
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• 제22권4호
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• pp.357-364
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• 2006

This study was undertaken to develop a reliable mice model demonstrating similar immunologic phenomena as human atopic dermatitis characterized with predominance of type-2 immune response. BALB/C mice and NC/Nga mice were sensitized twice with $100{\mu}l$ of 1% 2,4-dinitrochlorobenzene (DNCB) or vehicle (acetone : olive oil=4:1 mixture) in a week and challenged twice with $100{\mu}l$ of 0.2% DNCB or the vehicle at the following week. Mice were sacrificed at 19 days following the second DNCB or vehicle challenge for NC/Nga mice and at 28 days following the second DNCB or vehicle challenge for BALB/c mice. Upregulation of plasma 1gE, a hallmark of atopic dermatitis occurrence, was evident in the plasma obtained 4 day after the second DNCB challenge from BALB/c mice (approximately 4-fold) and NC/Nga mice (approximately 6-fold) treated with DNCB in comparison with that of the vehicle treated-control mice, and remain higher $3{\sim}4$ week after the second challenge. Ratio of plasma IgG1 versus IgG2a concentration was significantly higher in the mice treated with DNCB than the control mice, which also implies the skewed type-2 reactivity in vivo. Ratio of interleukin-4 versus interferon gamma produced in the splenic T cell culture supernatants was approximately 3-fold higher in the both strains of mice treated with DNCB than their control mice, respectively. The DNCB-treated mice demonstrated atopic dermatitis-like skin legions characterized with erythma, scaling, and hemorrhage, which was not observed with the control mice. Scratching on face or dorsal area was significantly more frequent (approximately 25-fold) in the DNCB-treated mice than the control at next day of the second DNCB challenge, and scratching frequency remains higher (approximately 4-fold) in the mice treated with DNCB than the control at 14 day following the second DNCB challenge. Overall, the mice model developed through sensitization and challenge with DNCB may be useful for research on atopic dermatitis and development of treatment materials for atopic dermatitis.

• 한국컴퓨터정보학회논문지
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• 제17권11호
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• pp.163-171
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• 2012

온라인게임에 관한 대다수의 연구들은 주로 심리학자들에 의한 인터넷 중독과 과학자들에 의한 관련기술의 개발에 관해 수행되어왔다. 온라인 비즈니스 모델의 관점에서 고객만족을 연구한 논문은 드문 편이다. 본 연구의 목적은 온라인게임 이용자들을 대상으로 고객만족과 주요 요인들 간의 인과관계를 조사하는 것이다. 이를 위해 연구모델은 고객만족에 영향을 미치는 주요 요인들을 규명하기 위해 상호작용, 즐거움, 도전, 보상, 디자인의 개념을 이용하였다. 연구결과 상호작용, 즐거움, 도전 요인이 온라인게임 이용자들의 고객만족에 유의한 영향을 미치는 요인으로 규명되었다. 온라인게임 이용자들의 만족도에 영향을 미치는 주요 요인에 관한 연구는 지속적으로 논의되고 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제24권5호
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• pp.696-706
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• 2011

The objective of this study was to characterize serum immunoglobulins and lymphocytes subpopulations in the peripheral blood mononuclear cells (PBMCs) of Holstein calves in response to lipopolysaccharide (LPS) challenge from Escherichia coli. Fourteen calves received subcutaneous injections of E. coli LPS at 10 weeks of age, and six calves were injected with saline as a control. The concentrations of total serum IgG and the relative amount of LPS-specific IgG in calves challenged with LPS were significantly higher (p<0.05) compared to control animals and LPS challenge significantly increased (p<0.05) the percentage of $CD5^+$ and $CD21^+$ T cells in PBMCs. Meanwhile, LPS challenge significantly increased (p<0.05, p<0.01) the percentage of $CD8^+$ and $CD25^+$ T cells in peripheral blood mononuclear cells (PBMC) at 7 and 14 Day-post LPS challenge (DPLC), respectively. The composition of $CD4^+CD25^+$ T cells and $CD8^+CD25^+$ T cells from calves challenged with LPS was also higher (p<0.05 and p = 0.562, respectively) than those of control calves at 14 DPLC. In conclusion, LPS challenge not only induces production of IgG with expression of B-cell immune response related cell surface molecules, but also stimulates activation of T-lymphocytes in PBMC. Our results suggest that LPS challenge in calves is a good model to elucidate cellular immune response against Gram-negative bacterial infections.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.110-115
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• 2004

The hybrid fault diagnosis method based on a combination of the signed digraph (SDG) and the partial least-squares (PLS) has the advantage of improving the diagnosis resolution, accuracy and reliability, compared to those of previous qualitative methods, and of enhancing the ability to diagnose multiple fault. In this study, the method is applied for the multiple fault diagnosis of the Tennessee Eastman challenge process, which is a realistic industrial process for evaluating process contol and monitoring methods. The process is decomposed using the local qualitative relationships of each measured variable. Dynamic PLS (DPLS) model is built to estimate each measured variable, which is then compared with the estimated value in order to diagnose the fault. Through case studies of 15 single faults and 44 double faults, the proposed method demonstrated a good diagnosis capability compared with previous statistical methods.