• Structural Engineering and Mechanics
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• 제46권6호
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• pp.755-773
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• 2013

One of the main requirements of the seismic design codes must be its easy application by structural engineers. The use of practically-applicable models or simplified models as single-degree-of-freedom (SDOF) systems is a good alternative to achieve this condition. In this study, deterministic and probabilistic response transformation factors are obtained to evaluate the response in terms of maximum ductility and maximum interstory drifts of multi-degree-of-freedom (MDOF) systems based on the response of equivalent SDOF systems. For this aim, five steel frames designed with the Mexican City Building Code (MCBC) as well as their corresponding equivalent SDOF systems (which represent the characteristics of the frames) are analyzed. Both structural systems are subjected to ground motions records. For the MDOF and the simplified systems, incremental dynamic analyses IDAs are developed in first place, then, structural demand hazard curves are obtained. The ratio between the IDAs curves corresponding to the MDOF systems and the curves corresponding to the simplified models are used to obtain deterministic response transformation factors. On the other hand, demand hazard curves are used to calculate probabilistic response transformation factors. It was found that both approaches give place to similar results.

• 한국지반공학회논문집
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• 제25권8호
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• pp.57-64
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• 2009

본 연구에서는 등가변형을 이용하며 테이퍼 말뚝의 지지력을 산정하는 방법을 제안하였다. 지반조건과 테이퍼각도를 고려하여 지지력을 산정하던 기존의 방법과 달리, 테이퍼말뚝의 지지력산정시 콘관입시험 결과를 활용하도록 하였다. 이때 테이퍼말뚝은 등가변형을 이용하여 형태를 단순화 시켰으며 이를 통해 실무에서 비교적 쉽게 지지력을 산정 할 수 있는 방법을 제안하였다. 제안된 방법의 검증을 위해 실내시험과 현장시험을 실시하였다. 실내모형시험 결과로부터 측정된 극한지지력과 본 연구에서 제안된 방법에 의한 예측값을 비교한 결과 표준편차는 $0.05{\sim}0.121$, COV는 $0.04{\sim}0.05$의 값을 보여 대체적으로 유사한 결과를 보였으며, 현장시험은 약 2.5%의 오차를 보여 측정값에 근접함을 알 수 있었다. 그 결과 제안된 지지력 산정법은 테이퍼말뚝의 지지력을 비교적 정확하게 예측하는 것으로 나타났다.

• Restorative Dentistry and Endodontics
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• 제46권4호
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• pp.54.1-54.10
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• 2021

Objectives: The purpose of this study was to quantify phase transformation after hydrofluoric acid (HF) etching at various concentrations on the surface of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP), and to evaluate changes in bonding strength before and after thermal cycling. Materials and Methods: A group whose Y-TZP surface was treated with tribochemical silica abrasion (TS) was used as the control. Y-TZP specimens from each experimental group were etched with 5%, 10%, 20%, and 40% HF solutions at room temperature for 10 minutes. First, to quantify the phase transformation, Y-TZP specimens (n = 5) treated with TS, 5%, 10%, 20% and 40% HF solutions were subjected to X-ray diffraction. Second, to evaluate the change in bond strength before and after thermal cycling, zirconia primer and MDP-containing resin cement were sequentially applied to the Y-TZP specimen. After 5,000 thermal cycles for half of the Y-TZP specimens, shear bond strength was measured for all experimental groups (n = 10). Results: The monoclinic phase content in the 40% HF-treated group was higher than that of the 5%, 10%, and 20% HF-treated groups, but lower than that of TS-treated group (p < 0.05). The 40% HF-treated group showed significantly higher bonding strength than the TS, 5%, and 10% HF-treated groups, even after thermal cycling (p < 0.05). Conclusions: Through this experiment, the group treated with SiO₂ containing air-borne abrasion on the Y-TZP surface showed higher phase transformation and higher reduction in bonding strength after thermal cycling compared to the group treated with high concentration HF.

• 대한임상검사과학회지
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• 제43권3호
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• pp.89-97
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• 2011

The Human Papilloma Virus (HPV) infection has been strongly associated with pathogenesis of uterine cervix carcinoma. HPV type 16, a causative agent of uterine cervix carcinoma, encodes the E6 and E7 oncogenes, expression of which is pivotal for malignant transformation and maintenance of malignant phenotypes. To develop a gene therapy for HPV-related carcinoma, We investigated the effect of E6 short-interfering RNA (E6 siRNA) on the expression of this oncogene and on the growth of HPV 16-related uterine cervix carcinoma cells. SiHa cells, a uterine cervix carcinoma cell line, which contain a single copy of HPV 16 integrated in the chromosome and express the E6 and E7 oncogenes. Before 24 hr of transfection, cells were seeded and transfected with control plasmid or E6 siRNA-expressing plasmid. The mRNA was analysed by reverse transcriptase polymerase chain reaction (RT-PCR). The cell growth rate was investigated by MTT method. The E6 mRNA level in SiHa cells was decreased in HPV 16 E6 siRNA-expression vector transfected cells and a decrease in the growth of these cells was also observed. From these results. it is evident that E6 siRNA played a role in suppression of growth of SiHa cells and has a fair chance as a candidate for gene specific therapy for HPV related uterine cervix carcinoma.

• Toxicological Research
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• 제30권4호
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• pp.261-266
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• 2014

Environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs) have been implicated in cancer development and progression. However, the effects of PAHs on carcinogenesis are still poorly understood. Here, we characterized a mouse cancer cell line BNL 1ME A. 7R.1 (1MEA) derived by transformation of non-tumorigenic liver cell line BNL CL.2 (BNL) using 3-methylcholanthrene (3MC), a carcinogenic PAH. RT-PCR and immunoblot analysis were used to determine the expression level of mRNA and proteins, respectively. To determine functionality, cell motility was assessed in vitro using a transwell migration assay. Both mRNA and protein levels of E-cadherin were significantly decreased in 1MEA cells in comparison with BNL cells. While the expression levels of mesenchymal markers and related transcription factors were enhanced in 1MEA cells, which could lead to increase in cell motility. Indeed, we found that 7-day exposure of BNL cells to 3-MC reduced the level of the adhesion molecule and epithelial marker E-cadherin and increased reciprocally the level of the mesenchymal marker vimentin in a dose-dependent manner. Taken together, these results indicate that the process of epithelial-mesenchymal transition (EMT) may be activated during premalignant transformation induced by 3-MC. A mechanism study to elucidate the relation between 3-MC exposure and EMT is underway in our laboratory.

• Mycobiology
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• 제49권5호
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• pp.491-497
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• 2021

An endolichenic fungus Xylaria grammica EL000614 produces grammicin, a potent nematicidal pyrone derivative that can serve as a new control option for root-knot nematodes. We optimized an Agrobacterium tumefaciens-mediated transformation (ATMT) protocol for X. grammica to support genetic studies. Transformants were successfully generated after co-cultivation of homogenized young mycelia of X. grammica with A. tumefaciens strain AGL-1 carrying a binary vector that contains the bacterial hygromycin B phosphotransferase (hph) gene and the eGFP gene in T-DNA. The resulting transformants were mitotically stable, and PCR analysis showed the integratin of both genes in the genome of transformants. Expression of eGFP was confirmed via fluorescence microscopy. Southern analysis showed that 131 (78.9%) out of 166 transformants contained a single T-DNA insertion. Crucial factors for producing predominantly single T-DNA transformants include 48 h of co-cultivation, pretreatment of A. tumefaciens cells with acetosyringone before co-cultivation, and using freshly prepared mycelia. The established ATMT protocol offers an efficient tool for random insertional mutagenesis and gene transfer in studying the biology and ecology of X. grammica.

• 아태비즈니스연구
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• 제12권4호
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• pp.271-288
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• 2021

Purpose - The purpose of this study is to identify the critical factors that restaurant management should consider strategically when making a decision after COVID-19 under the digital transformation and non-contact service expansions environment. Design/methodology/approach - The thirty six experts and managers who have 5 years or more experience in restaurant industry in Korea participate this study. The Analytic Hierarchy Process (AHP) and SER-M were used to analyze the experts' opinion Findings - As a result of the analysis, 'management environment' (0.313) showed the highest relative importance priority, followed by 'brand (0.263)', 'management characteristics (0.254)', and 'physical factors (0.17)'. And, as for the sub-factor value, 'lifestyle (0.087)', 'awareness (0.084)', 'consumer desire (0.075)', and 'loyalty (0.068)' were ranked highest among the 19 influencing critical factors. Research implications or Originality - In the case of large restaurant enterprises, it is judged that the subject(CEO, Management) is actively pursuing a strategy to acquire the necessary resources for the given environment of digital transformation and customer demand for non-contact services. On the other hand, in the case of middle and small restaurant enterprises, it seems that they are fully aware of the demand for expansion of non-contact services and the digital transformation required in the post COVID-19 era, but information technology utilization ability, usage experience, technology acceptance ability, and education and training support for this are only available to large enterprises.

• Journal of Microbiology and Biotechnology
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• 제34권2호
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• pp.467-475
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• 2024

ρ-Hydroxyacetophenone is an important and versatile compound that has been widely used in medicine, cosmetics, new materials, and other fields. At present, there are two ways to obtain ρ-hydroxyacetophenone. One is to extract it from plants, such as Artemisia capillaris Thunb and Cynanchum otophyllum Schneid, and the other is to synthesize it by using chemical methods. Of these two methods, the second is the main one, although it has problems, such as flammable and explosive reagents, difficult separation of by-products, and harsh reaction conditions. To solve these issues, we adopted genetic engineering in this study to construct engineered Escherichia coli containing Hped gene or EbA309 gene. Whole-cell biotransformation was conducted under the same conditions to select the engineered E. coli with the higher activity. Orthogonal tests were conducted to determine the optimal biotransformation condition of the engineered E. coli. The results showed that the optimal condition was as follows: substrate concentration of 40 mmol/l, IPTG concentration of 0.1 mmol/l, an induction temperature of 25℃, and a transformation temperature of 35℃. Under this condition, the effects of transformation time on the ρ-hydroxyacetophenone concentration and cell growth were further studied. We found that as the transformation time extended, the ρ-hydroxyacetophenone concentration showed a gradually increasing trend. However, when the ρ-hydroxyacetophenone concentration increased to 1583.19 ± 44.34 mg/l in 24 h, cell growth was inhibited and then entered a plateau. In this research, we realized the synthesis of ρ-hydroxyacetophenone by biotransformation, and our findings lay a preliminary foundation for further improving and developing this method.

• 한국식품과학회지
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• 제22권6호
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• pp.632-639
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• 1990

곰취, 참취 그리고 참나물로부터 polyphenoloxidase를 추출하여 polyphenol 화합물인 pyrogallol, hydroxyhyd-roquinone, catechol 그리고 3,4-dihydroxytoluene과 반응시켜 얻어진 12종류의 효소갈변반응 생성물의 생리작용을 검토한 결과 시료 모두 rec-assay, 돌연변이원성 실험 그리고 DNA 절단실험에서 돌연병원성을 나타내지 않았다. 그러나 12종류의 시료 모두 S-9mix를 첨가한 Salmonella/microsomal 실험에서 $benzo({\alpha})pyrene(B({\alpha})P)$, 3-amino-1,4-dimethyl-5H-pyrido(4,3-b) indole(Trp-P-1) 그리고 2-aminofluorene(2-AF) 등 변이원 물질들을 강하게 억제시키는 활성을 나타내었다. DNA repair 실험에서 효소갈변반응 생성물의 E. coli HB101에 plasmid pGA658의 transformation 빈도수는 곰취 효소갈변반응 생성물의 첨가에 의해 높은 수치를 나타내었으며 transformation 전에 DNA와 효소갈변반응 생성물을 혼합하여 자외선을 조사하였을 때 곰취의 pyrogallol, catechol, hydroxyhydroquinone의 효소갈변반응 생성물은 높은 수치를 나타내었다.

• 한국전자거래학회지
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• 제1권2호
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• pp.49-76
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• 1996

An industrial process is a sequence of steps intended to perform a useful task in an industrial organization, and can be described using a model or a representation framework such as function model, information model, process flow model, etc. Many researchers, however, claim that, all those models from different perspectives are required to describe complex systems such as CIMS. Thus these perspectives should be put together to build an optimal system. And the need for interconnection or transformation among different view points has arisen for effective communications between system developers and easy propogation of local changes in a model. But it seems to be difficult to integrate such models into a unified framework as they describe different aspects of the system on different purposes. This study is an attempt to interconnect these different perspectives, and thereby to support conceptual design of systems in a more effective manner. A methodology to transform the IDEFO functional model into a process flow model is proposed. The validity of the proposed approach is tested by developing a prototye of a computer-assisted design system on the operation processes of FMS installed at Seoul National University - Automation and Systems Research Institute.