• Journal of Ginseng Research
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• 제40권1호
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• pp.47-54
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• 2016

Background: The roots of Panax ginseng contain noble tetracyclic triterpenoid saponins derived from dammarenediol-II. Dammarene-type ginsenosides are classified into the protopanaxadiol (PPD) and protopanaxatriol (PPT) groups based on their triterpene aglycone structures. Two cytochrome P450 (CYP) genes (CYP716A47 and CYP716A53v2) are critical for the production of PPD and PPT aglycones, respectively. CYP716A53v2 is a protopanaxadiol 6-hydroxylase that catalyzes PPT production from PPD in P. ginseng. Methods: We constructed transgenic P. ginseng lines overexpressing or silencing (via RNA interference) the CYP716A53v2 gene and analyzed changes in their ginsenoside profiles. Result: Overexpression of CYP716A53v2 led to increased accumulation of CYP716A53v2 mRNA in all transgenic roots compared to nontransgenic roots. Conversely, silencing of CYP716A53v2 mRNA in RNAi transgenic roots resulted in reduced CYP716A53v2 transcription. HPLC analysis revealed that transgenic roots overexpressing CYP716A53v2 contained higher levels of PPT-group ginsenosides ($Rg_1$, Re, and Rf) but lower levels of PPD-group ginsenosides (Rb1, Rc, $Rb_2$, and Rd). By contrast, RNAi transgenic roots contained lower levels of PPT-group compounds and higher levels of PPD-group compounds. Conclusion: The production of PPD- and PPT-group ginsenosides can be altered by changing the expression of CYP716A53v2 in transgenic P. ginseng. The biological activities of PPD-group ginsenosides are known to differ from those of the PPT group. Thus, increasing or decreasing the levels of PPT-group ginsenosides in transgenic P. ginseng may yield new medicinal uses for transgenic P. ginseng.

• International Journal of Railway
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• 제8권2호
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• pp.50-54
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• 2015

The primary function of the trackbed in a conventional railway track system is to decrease the stresses in the subgrade to be in an acceptable level. A properly designed trackbed layer performs this task adequately. Many design procedures have used assumed and/or are based on critical stiffness values of the layers obtained mostly in the field to calculate an appropriate thickness of the sublayers of the trackbed foundation. However, those stiffness values do not consider strain levels clearly and precisely in the layers. This study proposes a method of computation of stiffness that can handle with strain level in the layers of the trackbed foundation in order to provide properly selected design values of the stiffness of the layers. The shear modulus values are dependent on shear strain level so that the strain levels generated in the subgrade in the trackbed under wheel loading and below plate of Repeated Plate Bearing Test (RPBT) are investigated by finite element analysis program ABAQUS and PLAXIS programs. The strain levels generated in the subgrade from RPBT are compared to those values from RC (Resonant Column) test after some consideration of strain levels and stress consideration. For comparison of shear modulus G obtained from RC test and stiffness moduli $E_{v2}$ obtained from RPBT in the field, many numbers of mid-size RC tests in laboratory and RPBT in field were performed extensively. It was found in this study that there is a big difference in stiffness modulus when the converted $E_{v2}$ values were compared to those values of RC test. It is verified in this study that it is necessary to use precise and increased loading steps to construct nonlinear curves from RPBT in order to get correct $E_{v2}$ values in proper strain levels.

• Molecules and Cells
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• 제44권10호
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• pp.710-722
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• 2021

Hypoxia, or low oxygen tension, is a hallmark of the tumor microenvironment. The hypoxia-inducible factor-1α (HIF-1α) subunit plays a critical role in the adaptive cellular response of hypoxic tumor cells to low oxygen tension by activating gene-expression programs that control cancer cell metabolism, angiogenesis, and therapy resistance. Phosphorylation is involved in the stabilization and regulation of HIF-1α transcriptional activity. HIF-1α is activated by several factors, including the mitogen-activated protein kinase (MAPK) superfamily. MAPK phosphatase 3 (MKP-3) is a cytoplasmic dual-specificity phosphatase specific for extracellular signal-regulated kinase 1/2 (Erk1/2). Recent evidence indicates that hypoxia increases the endogenous levels of both MKP-3 mRNA and protein. However, its role in the response of cells to hypoxia is poorly understood. Herein, we demonstrated that small-interfering RNA (siRNA)-mediated knockdown of MKP-3 enhanced HIF-1α (not HIF-2α) levels. Conversely, MKP-3 overexpression suppressed HIF-1α (not HIF-2α) levels, as well as the expression levels of hypoxia-responsive genes (LDHA, CA9, GLUT-1, and VEGF), in hypoxic colon cancer cells. These findings indicated that MKP-3, induced by HIF-1α in hypoxia, negatively regulates HIF-1α protein levels and hypoxia-responsive genes. However, we also found that long-term hypoxia (>12 h) induced proteasomal degradation of MKP-3 in a lactic acid-dependent manner. Taken together, MKP-3 expression is modulated by the hypoxic conditions prevailing in colon cancer, and plays a role in cellular adaptation to tumor hypoxia and tumor progression. Thus, MKP-3 may serve as a potential therapeutic target for colon cancer treatment.

• 아태비즈니스연구
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• 제14권2호
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• pp.1-15
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• 2023

Purpose - This study investigates whether the inventory levels of Korean manufacturing firms increased or decreased from 2000 to 2019. We also explore the relationship between inventory levels and firm performance. Design/methodology/approach - We use panel data on KOSPI-listed firms in the manufacturing industry. We measure days in inventory as a proxy for inventory levels, and firm performance is measured by return on assets, return on sales, and EBITDA ratio. The panel data regression method is employed in our analysis. Findings - We find that days in inventory of Korean manufacturing firms significantly increased from 2000 to 2019, especially for raw materials and finished goods inventory. In addition, while days in inventory of large- and medium-sized firms were less than those of small-sized firms, the change in days in inventory of large- and medium-sized firms was positively significant over time. Moreover, the increase in days in inventory was more prevalent among industries related to foods, clothes, chemicals, and transportation. Finally, we show that the days in inventory are negatively related to firm performance. Research implications or Originality - While the Korean manufacturing industry has enormously grown over the last 20 years and managing inventory is critical in the manufacturing industry, our findings counter-intuitively show that the days in inventory of the Korean manufacturing industry had been gradually increased. We speculate that the increase in days in inventory is due to the Korean manufacturing firms' heavy reliance on global supply chains.

• 한국산학기술학회논문지
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• 제19권4호
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• pp.505-516
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• 2018

본 연구에서는 자기 비판적 완벽주의가 이상섭식행동에 미치는 영향력을 살펴보고, 이 과정을 자기은폐가 매개하는지에 대해 알아보았다. 이를 위해 대학생 348명을 대상으로 자기 비판적 완벽주의, 자기은폐, 이상섭식행동을 측정하였다. 먼저, 상관분석을 통해 각 변인 간의 관련성을 알아보았다. 그 결과, 자기 비판적 완벽주의는 자기은폐와 이상섭식행동과 유의한 정적 상관이 있었으며 자기 은폐 또한 이상섭식행동과 유의한 정적 상관이 있는 것으로 확인되었다. 그리고 구조방적식 모형을 검증하여 자기은폐가 자기 비판적 완벽주의와 이상섭식행동간의 관계를 부분 매개하는 것을 확인하였다. 즉, 자기 비판적 완벽주의는 직접적으로 이상섭식행동에 영향을 줄 뿐만 아니라, 높은 자기 은폐를 매개로 이상섭식행동을 증가시키는 것으로 확인되었다. 이러한 결과는 자신에게 높은 기준을 부여함과 동시에 스스로에게 비판적이고 타인의 부정적 평가를 두려워하는 특성을 가진 사람, 즉 자기 비판적 완벽주의자는 부정적인 사적인 정보를 숨기는 경향, 즉 자기은폐를 할 가능성이 높고 이로 인해 이상섭식행동을 보일 가능성이 높음을 의미한다. 본 연구의 결과를 바탕으로 후속연구를 위한 제언과 상담적 함의를 논의하였다.

• Child Health Nursing Research
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• 제20권4호
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• pp.294-303
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• 2014

목적 본 연구의 목적은 간호대학생의 비판적 사고성향과 문제해결과정 정도 및 시뮬레이션 기반 임상수행능력 평가 점수와의 상관관계를 파악하는 데에 있다. 방법 본 연구의 대상자는 일 간호대학 3학년 학생 214명으로 대상자의 비판적 사고성향과 문제해결과정 정도 및 시뮬레이션 기반 임상수행능력 평가 점수와의 관계를 파악하였다. 비판적 사고성향은 Yoon (2008)이 개발한 5점 척도의 도구를 사용하여 측정하였고, 문제해결과정 정도는 Lee 등(2008)가 개발한 5점 척도의 문제해결과정 측정도구, 시뮬레이션 기반 임상수행능력 평가는 연구자가 개발한 체크리스트를 사용하였다. 수집된 자료는 SPSS WIN 18.0 프로그램을 이용하여 기술통계, Pearson's correlation coefficients를 이용하여 분석하였다. 결과 간호대학생의 비판적 사고성향 정도는 $3.76{\pm}0.46$ (점수범위 1-5점), 문제해결과정 정도는 $3.67{\pm}0.47$ (점수범위 1-5점)으로 중간 이상의 점수를 보였다. 시뮬레이션 기반 임상수행능력 평가 점수는 비판적 사고 성향이 평균점수(3.67점) 이상으로 높은 간호대학생에게서 유의하게 높게 나타난 반면, 문제해결과정 정도와의 유의한 상관관계는 없는 것으로 조사되었다. 비판적 사고성향은 시뮬레이션 기반 임상수행능력 평가의 하부 영역 중 간호사정 영역에서 유의한 상관관계가 있는 것으로 나타났다. 결론 본 연구는 시뮬레이션 기반 학습은 간호학생들의 비판적 사고성향이 기반이 되어야 하며 비판적 사고 성향정도는 복합적인 상황에서 대상자의 상태를 파악하는 간호사정에서 긍정적 영향을 미친다는 근거를 제시하였다. 그러므로 간호대학생의 비판적 사고함양을 위한 지속적인 교육이 필요하다. 또한 시뮬레이션 기반 학습은 학습자의 이러한 강점과 약점을 고려하여 시뮬레이션 평가 전 단계에서 충분한 학습의 기회를 제공함으로써 질적으로 우수한 간호사에 대한 요구가 증대되는 현 시점에 효과적인 대응책이 될 수 있을 것이다.

• Tuberculosis and Respiratory Diseases
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• 제60권3호
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• pp.353-356
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• 2006

폐결핵 치료중 흉부엑스선상 악화 및 갑자기 발생한 하지 마비와 감각이상으로 자기공명영상 촬영후 급성 횡단척수염 진단 및 객담 검사상 다제내성 결핵균 검출로 2차 결핵약제와 스테로이드 병합치료를 시행하여 부분적으로 호전을 보였던 증례이다. 급성 횡단척수염은 매우 드문 질환이며 균주의 직접 침범이나 면역학적 기전으로 발생하나 후자가 더 가능성 있는 기전으로 생각되어지고 있다. 아직도 결핵 및 다제내성 결핵의 유병률이 높은 국내 상황에서 드물게 결핵이 원인으로 추정된 급성 횡단척수염의 증례를 보고하는 바이다.

• 한국환경농학회지
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• 제5권2호
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• pp.95-100
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• 1986

비소(砒素)의 토양처리(土壤處理)에 의한 수도체(水稻體)의 비소흡수(砒素吸收) 정도(程度) 및 생육(生育)에 미치는 영향(影響)을 조사(調査)하기 위하여 양토(壤土)와 사양토(砂壤土)에 수용성(水溶性) 염(鹽)인 $Na_2HAsO_4{\cdot}7H_2O$로 비소(砒素)의 농도(濃度)가 0, 10, 25, 50, 100 및 150 ppm되게 각각(各各) 처리(處理)하여 pot 시험(試驗)한 결과(結果)는 다음과 같다. 1) 수도수량(水稻收量)은 토양중(土壤中) 비소농도(砒素濃度)가 높아짐에 따라 유의성(有意性) 있게 감소(減少)되었고 토성별(土性別) 유의성(有意性)있는 감소농도(減收濃度)는 사양토(砂壤土)가 2.75ppm, 양토(壤土)가 6.79ppm이었다. 2) 수량구성요소(收量構成要素)도 토양중(土壤中) 비소농도(砒素濃度)가 높아질수록 유의성(有意性)있게 각각(各各) 감소(減少)되었고 이중 천입중(千粒重)이 가장 높은 상관(相關)($-0.893^{{\ast}{\ast}}$)을 나타내었다. 3) 수도체(水稻體) 비소(砒素)는 대부분(大部分) 뿌리에 축적(蓄積)되어 있고 소량(小量)이 지상부(地上部)로 이행(移行)되었으며 부위별(部位別) 함량(含量)은 뿌리>줄기>엽신(葉身)>엽초>현미(玄米)의 순(順)으로 높았다. 4) 부임입수(不姙粒數)는 토양중(土壤中) 비소농도(砒素濃度)가 높을수록 증가(增加)되었으며 토성별(土性別)로는 사양토구(砂壤土區)가 양토구(壤土區) 보다 더 많았다.

• Safety and Health at Work
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• 제8권3호
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• pp.267-275
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• 2017

Background: The mining industry is known worldwide for its highly risky and hazardous working environment. Technological advancement in ore extraction techniques for proliferation of production levels has caused further concern for safety in this industry. Research so far in the area of safety has revealed that the majority of incidents in hazardous industry take place because of human error, the control of which would enhance safety levels in working sites to a considerable extent. Methods: The present work focuses upon the analysis of human factors such as unsafe acts, preconditions for unsafe acts, unsafe leadership, and organizational influences. A modified human factor analysis and classification system (HFACS) was adopted and an accident predictive fuzzy reasoning approach (FRA)-based system was developed to predict the likelihood of accidents for manganese mines in India, using analysis of factors such as age, experience of worker, shift of work, etc. Results: The outcome of the analysis indicated that skill-based errors are most critical and require immediate attention for mitigation. The FRA-based accident prediction system developed gives an outcome as an indicative risk score associated with the identified accident-prone situation, based upon which a suitable plan for mitigation can be developed. Conclusion: Unsafe acts of the worker are the most critical human factors identified to be controlled on priority basis. A significant association of factors (namely age, experience of the worker, and shift of work) with unsafe acts performed by the operator is identified based upon which the FRA-based accident prediction model is proposed.

• Journal of Preventive Medicine and Public Health
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• 제15권1호
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• pp.131-137
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• 1982

For the purpose of the curative effects of oral D-penicillamine in lead poisoning, D-penicillamine was orally administered to 7 lead poisoned workers which were employed in glaze product industry dealing with the lead oxide ($Pb_3O_4$). The doses of D-penicillamine was 1,200mg per day which was administered by oral 7days schedules, taking for 5 days and stopping for the following 2days, repeatedly during 3 months period. (All the poisoned workers started working again in that industry after 1 month treatment, and were treated by oral D-penicillamine for 2 months still being exposed to contaminated environment.) In order to evaluate the curative effects of D-penicillamine, 10gm of whole blood and 24 hours urine were collected every 14 days during the curative period for laboratory analysis(hemoglobin, blood lead, urine $\sigma$-aminolevulinic acid, urine coproporphyrin, and urine lead levels) with the observation of the clinical symptoms. The results were as follows; 1. Oral D-penicillamine effected good curative results as that hemoglobin, blood lead, urine $\sigma$-aminolevulinic acid, and urine coproporphyrin levels were decreased below the critical level within 1 month treatment. 2. After re-exposure, oral D-penicillamine effected to some extent as that urine lead level was decreased below the critical level after 3 months treatment with disappearence of the clinical symptoms after 2 months treatment. However, the curative effects of oral D-penicillamine in the lead exposure state is questionable since increasement of blood lead level and remarkable decreasement of urine lead level after 3 months treatment can be observed.