• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.4
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• pp.461-473
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• 2000

This paper deals with a numerical model for the time-dependent analysis of steel and concrete composite beams with partial shear connection. A linear partial interaction theory is adopted in formulation of structural slip behavior, and the effect of concrete creep and shrinkage are considered. The proposed model is effective in simulating the slip behavior, combined with concrete creep and shrinkage, of multi-span continuous composite beams. Finally, correlation studies and several parameter studies are conducted with the objective to establish the validity of the proposed model.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.1
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• pp.10-18
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• 2016

RC(Reinfored Concrete) structures exposed to carbonation in urban city have durability degradation with extended service life and cracks in concrete causes a local accelerated carbonation. In the present work, crack effect on carbonation depth is investigated and the service life of RC structure is evaluated considering cracks from early age and time-dependent cracks based on the previous field investigation. DFP(Durability Failure Probability), safety index, and the related service life are calculated considering the time to crack width reaches to maximum crack width(0.3mm). The results with time effect on crack width show lower DFP and longer service life, which seems to be reasonable compared with conservative results from crack effect from initial stage. Furthermore, crack effect is evaluated to be insignificant on DFP and service life. The technique with time-dependent crack effect on carbonation can be effectively used for RC structure containing cracking in use.

• KSBB Journal
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• v.5 no.2
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• pp.113-118
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• 1990

This experiment was carried out to investigate the immuno-regulatory effects of histamine on IL-1 synthesis and Ca2+ uptake in P388Dl macrophage-like cell line. The addition of histamine (10-8-10-3 M) increased IL-1 production in P388D1, cells, in a dose dependent manner, the treatment of EGTA (10-7-10-4M) and Co2+ ion (10-5-10-4M) decreased macrophage-derived IL-1 activity, and the pretreatment of histamine at the peak of 10-4M significantly enhanced Ca2+ uptake to P388Dl Cells. These results suggested that exogenous histamine was effective on IL-1 production from macrophage and the intracellular Ca2+ uptake play a important role in histamine-stimulated IL-1 synthesis.

• Environmental Analysis Health and Toxicology
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• v.22 no.1 s.56
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• pp.65-71
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• 2007

유산균(Lactic acid bacteria)은 Escherichia coli와 Salmonella typhimurium과 같은 병원균에 대한 항균활성을 나타낼 뿐만 아니라 면역 증강효과를 나타내는 등 인체내에서 건강에 이로운 다양한 역할을 수행하는 것으로 알려졌다. 특히, Pediococcus pentosaseus와 몇몇 Lactobacillus 종으로부터 분리한 항균활성을 나타내는 peptide들인 safelac과 lactopad는 몇몇 암세포주의 성장을 억제하는 것으로 나타났다. 이에, 본 연구에서는 HT-29, SW 480 및 Caco-2와 같은 3종류의 인간의 결장암 세포주에 safelac과 lactopad를 투여하여 이들이 항암효과를 나타낼 수 있는 지를 분석하고자 하였다. XTT assay는 safelaf과 lactopad가 HT-29, SW 480 및 Caco-2의 성장을 억제하는 것으로 나타났으며, 특히, 이들 peptide들을 72시간동안 처리했을 때 나타나는 항암효과는 $3.1{\sim}100mg/mL$의 농도범위에서 유의한 결과를 나타내었으며, 분석한 농도 범위에서 용량 의존적인 방식으로 더 강한 효과를 나타내었다. RAW 264.7 세포주는 cytokine인 tumor-necrosis factor(TNF-${\alpha}$)의 생성에 미치는 이들 peptide들의 효과를 조사하기 위한 대식세포의 모델로써 이용되었다. RAW 264.7 세포주에서 TNF-${\alpha}$의 생성은 이들 peptide들에 의해 48시간 배양시 용량에 의존적인 방식으로 영향을 받는 것으로 나타났다. 따라서, 이러한 발견은 safelac과 lactopad와 같은 유산균으로부터 분리한 항균 peptide들이 결장암 세포에 대한 화학적 예방제로서의 잠재성을 갖고 있음을 시사하는 결과로서 주목된다.

• Microbiology and Biotechnology Letters
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• v.44 no.2
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• pp.194-200
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• 2016

Resveratrol, a polyphenolic compound present in many fruits and vegetables such as grapes, mulberries, and peanuts, has been reported to have various biological effects. However, the molecular mechanisms underlying resveratrol-induced apoptosis in A549 ovarian cancer cells are not well understood. In this study, we investigated the effect of resveratrol on A549 lung cancer cells (expressing wild-type p53) and compared it with that observed for SKOV3 ovarian cancer cells (expressing null-type p53). Resveratrol significantly inhibited the viability and proliferation of A549 cells in a concentration- and time-dependent manner, compared with its effects on SKOV3 cells. It also induced A549 cell apoptosis, but did not affect anoikis resistance. Furthermore, the viability and proliferation of p53-knockdown A549 cells were unaffected by the presence of resveratrol. Therefore, we demonstrate that the anticancer effect of resveratrol against A549 lung cancer cells is dependent on the presence of functional p53.

• Journal of the Korean Society of Safety
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• v.18 no.1
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• pp.108-115
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• 2003

Bridges are rated at two levels by either Load Factor Design (LFD) or Allowable Stress Design (ASD). The lower level rating is called Inventory Rating and the upper level rating is called Operating Rating. To maintain bridges effectively, there is an urgent need to assess actual bridge loading carrying capacity and to predict their remaining life from a system reliability viewpoint. The lifetime functions are introduced and explained to predict the time-dependent failure probability. The bridge studied in this paper was built 30 years ago in rural area. For this bridge, the load test and rehabilitation were conducted. The time-dependent system failure probability is predicted with or without rehabilitation. As a case study, an optional rehabilitation is suggested, and fir this rehabilitation, load rating is computed and the time-dependent system failure probability is predicted. Based on rehabilitation costs and extended service lifes, the optimal rehabilitation is suggested.

• Journal of Veterinary Clinics
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• v.30 no.6
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• pp.403-408
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• 2013

The objective of the present study is to detect the effect of ${\beta}$-glucan originated from Aureobasidium on the proliferation and collagen production in human dermal fibroblast cells with wound repopulation in vitro. The proliferative effects were assessed using a MTT assay as well as cell counts at 24 and 48 hr after treatment. Hydroxyproline was measured as an index of procollagen production with reverse-phase high pressure liquid chromatography. Oncostatin M was used as a reference agent. In glucagon treated group, dose-dependent and significant increase of optical density or fibroblast cell numbers was demonstrated, when compared with those of control from 0.1 mg/ml concentration. In addition, the numbers of cells which had migrated into the wound defects were more significantly and dose-dependently increased than those of non-treated control. However, no meaningful effects on the procollagen production were observed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.2
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• pp.168-173
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• 2012

We performed this study to develop antithrombotic agents from oriental medicine herb extracts. Polygonum cuspidatum has been traditionally used as an edible medical resources for the treatment of cancer, pyodermatitis, hepatitis, cystitis, and inflammation. However, the effects of Polygonum cuspidatum on thrombosis and platelet activation are not precisely understood. The antithrombotic and antiplatelet activities of Polygonum cuspidatum were investigated by assessing the effect of a 70% ethanol extract of Polygonum cuspidatum on blood coagulation, fibrinolysis, and platelet aggregation. Polygonum cuspidatum showed effective fibrinolytic activity at 10 mg/mL. Polygonum cuspidatum also inhibited adenosine diphosphate induced platelet aggregation. Furthermore, evaluation of anticoagulant activity showed that an extract of Polygonum cuspidatum prolonged coagulation time via activated partial thromboplastin time (APTT). Our results show that Polygonum cuspidatum can be a potential candidate for antiplatelet activity as well as a fibrinolytic agent.

• Proceedings of the Korea Contents Association Conference
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• 2003.11a
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• pp.285-289
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• 2003

In this paper, we present DTD-dependent object database schema design methods to efficiently store XML data and process path expression. The similarity between DTD graph model and the object database model, and the characteristics of object database, object references and set-valued attributes, are very profitable to store XML documents into object databases. We propose two kinds of schema design methods. We then compare and anayze space and time complexity for the methods.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.472-474
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• 2005

개념망은 상당히 도메인에 의존적인 언어자원에 해당한다. 따라서, 도메인이 다른 분야에 적용하고자 한다면, 많은 수정이 요구된다. 그러나 개념망의 편집은 언어 이해 능력이 뛰어난 언어학자들 조차도 상당히 많은 시간이 요구되는 작업이다. 대부분의 시간소요는 개념망의 전체적인 계층구조를 스캐닝하는 작업과 특정 노드를 검색하는 작업에 의한 것이다. 기 구축된 개념망을 분석하면 계층관계에 있는 어휘들간의 일관된 규칙을 발견할 수 있다. 이 논문에서는 어휘들의 뜻풀이와 상위어간의 관계성, 복합명사와 상위어간의 관계성을 통계적으로 분석하였다 분석된 결과를 기반으로 확률모델을 이용하여 상위어 추천 기능을 구현하였다. 상위어 추천 기능의 시간 절감 효과를 실험하기 위해 실험자 2인을 대상으로 개념망 구축에 소요되는 시간을 측정하였다. 상위어 추천 기능이 있는 지능형 워크벤치를 이용할 경우 개념망 작업 시간은 약 $65\%$정도로 단축되는 것을 확인할 수 있었다. 본 지능형 워크벤치는 다양한 도메인에서 요구되는 개념망 구축의 시간 비용 절감에 크게 기절할 것으로 기대된다.