• Journal of Electrical Engineering and Technology
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• 제8권5호
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• pp.991-1001
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• 2013

Instead of building new substations or transmission lines, proper installation of flexible AC transmission systems (FACTS) devices can make the transmission networks accommodate more power transfers with less expansion cost. In this paper, the problem to maximize power system loadability by optimally installing two types of FACTS devices, namely static var compensator (SVC) and thyristor controlled series compensator (TCSC), is formulated as a mixed discrete-continuous nonlinear optimization problem (MDCP). To reduce the complexity of the problem, the locations suitable for SVC and TCSC installations are first investigated with tangent vector technique and real power flow performance index (PI) sensitivity factor and, with the specified locations for SVC and TCSC installations, a set of schemes is formed. For each scheme with the specific locations for SVC and TCSC installations, the MDCP is reduced to a continuous nonlinear optimization problem and the computing efficiency can be largely improved. Finally, to cope with the technical and economic concerns simultaneously, the scheme with the biggest utilization index value is recommended. The IEEE-14 bus system and a practical power system are used to validate the proposed method.

• Geomechanics and Engineering
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• 제16권5호
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• pp.513-525
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• 2018

Slope stability of sensitive clayey soils is particularly important when subjected to strength loss and deformation. Except for progressive failure, for most sensitive and insensitive slopes, it is important to review the feasibility of conventional analysis methods based on peak strength since peak strength governs slope stability before yielding. In this study, as a part of efforts to understand the behavior of sensitive clay slopes, a total of 12 centrifuge tests were performed for artificially sensitive and insensitive clay slopes using San Francisco Bay Mud (PI = 50) and Yolo Loam (PI = 10). In terms of slope stability, the results were analyzed using the updated instability factor ($N_I$). $N_I$ using equivalent unit weight to cause a failure is in reasonable agreement shown in the Taylor's chart ($N_I$ ~ 5.5). In terms of dynamic deformation, it is shown that two-way sliding is a more accurate approach than conventional one-way sliding. Two-way sliding may relate to diffused shear surfaces. The outcome of this study is contributable to analyzing stability and deformation of steep sensitive clay slopes.

• 동의생리병리학회지
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• 제29권3호
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• pp.246-255
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• 2015

The purpose of this study is to investigate the reliability and validity of the questionnaire of pattern identification (PI) in traditional chinese medicine (TCM), through the systematic review of china national knowledge infrastructure (CNKI) database. We searched the articles related with reliability and validity of the questionnaire of PI and published from January 1994 to December 2013. Seventeen questionnaires were analyzed in this study. The twelve (70.6%) questionnaires were developed on the base of specific disease, and five (29.4%) ones were developed on the base of non-specific disease. Three of PI questionnaires showed low inter-item consistency reliability. Exploratory factor analysis of construct validity, content validity, and criterion validity analysis were commonly used on the assessment of validity, but none of them was analysed at the same study. There was only one questionnaire of the ischemic stroke that examined the sensitivity and specificity of both training and test groups in spite of the absence of a gold standard.

• Psychiatry investigation
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• 제15권11호
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• pp.1053-1063
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• 2018

Objective This study evaluated the psychometric properties of the Korean Anxiety Screening Assessment (K-ANX) developed for screening anxiety disorders. Methods Data from 613 participants were analyzed. The K-ANX was evaluated for reliability using Cronbach's alpha, item-total correlation, and test information curve, and for validity using focus group interviews, factor analysis, correlational analysis, and item characteristics based on item response theory (IRT). The diagnostic sensitivity and specificity of the K-ANX were compared with those of the Beck Anxiety Inventory (BAI) and Generalized Anxiety Disorder 7-item scale (GAD-7). Results The K-ANX showed excellent internal consistency (${\alpha}=0.97$) and item-total coefficients (0.92-0.97), and a one-factor structure was suggested. All items were highly correlated with the total scores of the BAI, GAD-7, and Penn State Worry Questionnaire. IRT analysis indicated the K-ANX was most informative as a screening tool for anxiety disorders at the range between 0.8 and 1.6 (i.e., top 21.2 to 5.5 percentiles). Higher sensitivity (0.795) and specificity (0.937) for identifying anxiety disorders were observed in the K-ANX compared to the BAI and GAD-7. Conclusion The K-ANX is a reliable and valid measure to screen anxiety disorders in a Korean sample, with greater sensitivity and specificity than current measures of anxiety symptoms.

• Molecules and Cells
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• 제41권3호
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• pp.244-255
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• 2018

Low-grade pro-inflammatory state and leptin resistance are important underlying mechanisms that contribute to obesity-associated hypertension. We tested the hypothesis that Astragaloside IV (As IV), known to counteract obesity and hypertension, could prevent obesity-associated hypertension by inhibiting pro-inflammatory reaction and leptin resistance. High-fat diet (HFD) induced obese rats were randomly assigned to three groups: the HFD control group (HF con group), As IV group, and the As IV + ${\alpha}$-bungaratoxin (${\alpha}-BGT$) group (As IV+${\alpha}-BGT$ group). As IV ($20mg{\cdot}Kg^{-1}{\cdot}d^{-1}$) was administrated to rats for 6 weeks via daily oral gavage. Body weight and blood pressure were continuously measured, and NE levels in the plasma and renal cortex was evaluated to reflect the sympathetic activity. The expressions of leptin receptor (LepRb) mRNA, phosphorylated signal transducer and activator of transcription-3 (p-STAT3), phosphorylated phosphatidylinositol 3-kinase (p-PI3K), suppressor of cytokine signaling 3 (SOCS3) mRNA, and protein-tyrosine phosphatase 1B (PTP1B) mRNA, pro-opiomelanocortin (POMC) mRNA and neuropeptide Y (NPY) mRNA were measured by Western blot or qRT-PCR to evaluate the hypothalamic leptin sensitivity. Additionally, we measured the protein or mRNA levels of ${\alpha}7nAChR$, inhibitor of nuclear factor ${\kappa}B$ kinase subunit ${\beta}/nuclear$ factor ${\kappa}B$ ($IKK{\beta}/NF-KB$) and pro-inflammatory cytokines ($IL-1{\beta}$ and $TNF-{\alpha}$) in hypothalamus and adipose tissue to reflect the anti-inflammatory effects of As IV through upregulating expression of ${\alpha}7nAChR$. We found that As IV prevented body weight gain and adipose accumulation, and also improved metabolic disorders in HFD rats. Furthermore, As IV decreased BP and HR, as well as NE levels in blood and renal tissue. In the hypothalamus, As IV alleviated leptin resistance as evidenced by the increased p-STAT3, LepRb mRNA and POMC mRNA, and decreased p-PI3K, SOCS3 mRNA, and PTP1B mRNA. The effects of As IV on leptin sensitivity were related in part to the up-regulated ${\alpha}7nAchR$ and suppressed $IKK{\beta}/NF-KB$ signaling and pro-inflammatory cytokines in the hypothalamus and adipose tissue, since co-administration of ${\alpha}7nAChR$ selective antagonist ${\alpha}-BGT$ could weaken the improved effect of As IV on central leptin resistance. Our study suggested that As IV could efficiently prevent obesityassociated hypertension through inhibiting inflammatory reaction and improving leptin resistance; furthermore, these effects of As IV was partly related to the increased ${\alpha}7nAchR$ expression.

• Asian Pacific Journal of Cancer Prevention
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• 제14권7호
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• pp.4049-4052
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• 2013

Resistance to chemotherapy treatment, which may lead to limited efficacy of systemic therapy in breast cancer patients, is multifactorial. Among the mechanisms of resistance to chemotherapy treatment, there are those closely related to estrogen receptor ${\alpha}$, P-glycoprotein, multidrug resistance-related protein, glutathione S-transferase pi and topoisomerase-II. $ER{\alpha}$ is ligand-activated transcription factor that regulates gene expression and plays a critical role in endocrine signaling. In previous preclinical and clinical studies, positive $ER{\alpha}$ expression in breast cancer cells was correlated with decreased sensitivity to chemotherapy. This article reviews current knowledge on the predictive value of $ER{\alpha}$ with regard to response to chemotherapy. Better understanding of its role may facilitate patient selection of therapeutic regimens and lead to optimal clinical outcomes.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.6135-6140
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• 2013

Background: Breast cancer is a common malignant tumor which affects health of women and multidrug resistance (MDR) is one of the main factors leading to failure of chemotherapy. This study was conducted to establish paclitaxel-resistant breast cancer cell line and nude mice models to explore underlying mechanisms of MDR. Methods: The breast cancer drug-sensitive cell line MCF-7 (MCF-7/S) was exposed in stepwise escalating paclitaxel (TAX) to induce a resistant cell line MCF-7/TAX. Cell sensitivity to drugs and growth curves were measured by MTT assay. Changes of cell morphology and ultrastructure were examined by optical and electron microscopy. The cell cycle distribution was determined by flow cytometry. Furthermore, expression of proteins related to breast cancer occurrence and MDR was tested by immunocytochemistry. In Vivo, nude mice were injected with MCF-7/S and MCF-7/TAX cells and weights and tumor sizes were observed after paclitaxel treatment. In addition, proteins involved breast cancer and MDR were detected by immunohistochemistry. Results: Compared to MCF-7/S, MCF-7/TAX cells had a higher resistance to paclitaxel, cross-resistance and prolonged doubling time. Moreover, MCF-7/TAX showed obvious alterations of ultrastructure. Estrogen receptor (ER) expression was low in drug resistant cells and tumors while expression of human epidermal growth factor receptor 2 (HER2) and Ki-67 was up-regulated. P-glycoprotein (P-gp), lung resistance-related protein (LRP) and glutathione-S-transferase-${\pi}$ (GST-${\pi}$) involved in the MDR phenotype of resistant cells and tumors were all overexpressed. Conclusion: The underlying MDR mechanism of breast cancer may involve increased expression of P-gp, LRP and GST-${\pi}$.

• 생명과학회지
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• 제17권1호
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• pp.56-63
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• 2007

인슐린은 지방세포 또는 근육세포에서 포도당 흡수 조절 통로단백질이 함유되어 있는 소포제를 세포막으로의 이동을 촉진시킨다. 우리는 여기서 지방세포로의 분화는 인슐린에 의한 포도당 흡수에 대한 반응이 증가됨을 보였다. 반면에 지방세포로의 분화는 PDGF에 의한 포도당 흡수 반응이 감소됨을 보였다. 인슐린 수용체나 caveolae는 지방세포로의 분화과정 동안 발현이 증가된다. 또한 지방세포로의 분화는 인슐린에 의한 Akt의 활성을 증가시켰다. 하지만 PDGF에 의한 Akt의 활성은 크게 감소하였다. 하지만 인슐린은 지방세포 또는 섬유아 전구세포에서 ERK의 활성을 유도하지 않았다. PDGF에 의한 ERK 활성 또한 지방세포로의 분화과정에 따라 감소하였다. P13K의 저해제인 LY294002는 지방세포 뿐만 아니라 섬유아 전구세포에서 인슐린에 의한 포도당 흡수를 저해하였다. 마지막으로 인슐린 수용체, Akt, SHIP2, p85등이 lipid raft/caveolae에 존재함을 확인하였고 인슐린에 의해 이런 단백질들이 lipid raft/caveolae로 이동함을 관찰하였다. 이런 결과를 토대로 lipid raft는 포도당 홉수를 위한 인슐린의 기능적 작용을 하는데 매우 중요한 환경을 제공함을 주장한다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권12호
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• pp.6311-6318
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• 2012

Background: HER2/neu overexpression due to gene amplification is an important factor in breast cancer, modifying the sensitivity to anti-HER2 monoclonal antibody therapy. The clinical significance of HER2 expression in non small cell lung carcinoma (NSCLC) is currently under evaluation. The tumor suppressor gene PTEN negatively regulates the HER2/PI3K/Akt signalling pathway. The purpose of this study was to evaluate the role of simultaneous alteration in HER2 and PTEN protein expression in relation to biological behaviour of NSCLCs. Materials and Methods: Protein expression was determined by immunohistochemistry in sixty-one (n=61) NSCLC cases along with CISH for HER2 gene analysis and detection of chromosome 17 aneuploidy. Patients were followed-up for a period of 34 to 41 months after surgery. Results: HER2 overexpression (2+/3+score) was detected in 17 (27.9%) patients while loss of PTEN expression was observed in 24 (39.3%) cases, low expression in 29 (47.6%) and overexpression in 8 (13.1%). Simultaneous HER2 overexpression and PTEN low/loss of expression were correlated with metastasis (71.4% vs 36.2% p=0.03). Analysis in the subgroup of 22 patients of pTNM stage III with lymph node status N1 or N2 revealed that there was a relationship between the number of positive regional lymph node groups and simultaneous deregulation of the two genes (p=0.04). Multivariate analysis determined that HER2 overexpression was associated with an increasing risk of developing metastases (OR: 4.3; 95%CI: 1.2-15.9; p: 0.03) while PTEN overexpression was associated with lower risk (OR: 0.1; 95%CI: 0.1, 1.0; p: 0.05). Conclusions: Simultaneous HER2/PTEN deregulation is a significant genetic event that leads to a more aggressive phenotype of NSCLC.

• Tuberculosis and Respiratory Diseases
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• 제58권5호
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• pp.473-479
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• 2005

연구 배경 : Gefitinib은 경구용 상피세포 성장인자 수용체 억제제로서 주로 동양인, 여성, 비흡연가, 선암 세포형의 폐암 환자에서 반응율이 좋은 것으로 되어 있으나 그 정확한 기전에 대해 밝혀진 것을 없다. 최근 몇몇 보고에 의하면 병기가 진행된 폐암 세포에서 PTEN 발현이 감소되어 있었으며, 또한 PTEN 발현이 감소된 폐암 세포주에서 EGFR tyrosine kinase inhibitor의 반응율이 감소되었음을 보고한 논문들이 있다. 이에 저자들은 본원에서 비소세포 폐암으로 진단받고 표준 항암화학요법에 실패한 이후 gefitinib으로 치료받은 환자군의 폐조직을 대상으로 PTEN의 발현 정도를 조사하였으며, PTEN의 발현 정도와 임상병기, 치료반응율과의 상관관계에 대해 분석하였다. 대상 및 방법 : 2002년 1월부터 2004년 8월까지 본원에 내원하여 원발성 비소세포성 폐암 진단 받은 후 표준 항암 화학요법에 실패하고 gefitinib을 복용한 환자 38명 중 2개월 이상을 투여 받아 반응 정도를 평가가 가능한 환자로서 폐조직에 대해 PTEN 면역조직화학 염색 및 정량화를 시행할 수 있었던 22명의 환자들에 대해 환자들의 약제 반응율과 PTEN의 발현양상과의 관계에 대해 후향적으로 조사하였다. 결 과 : 평균 연령은 62세, 남녀의 비는 6.3:1이었으며, 조직 병리학적 분류는 편평상피암 32%, 선암 59%, 대세포암 등 기타가 9%였다. 병기는 I 병기 1례, II 병기 1례, III 병기 9례, IV 병기가 11례였다. ECOG performance status는 grade 0-1이 9명, 2가 11명, 3이 2명이었다. 조직 병리학적 분류에 따른 PTEN 발현의 유의한 차이는 없었다. 또한 TNM 병기 상승에 따른 PTEN 발현율과는 서로 통계적으로 유의한 차이가 없었다. 그 러나, 약제 반응을 보인 군에서 약제 반응을 보이지 않은 군보다 PTEN 발현율이 통계적으로 유의하게 높게 나타났다(p=0.039). 결 론 : 표준 항암 화학 요법에 실패하고 gefitinib을 복용한 비소세포 폐암 환자의 약제 반응율과 종양 억제 단백질인 PTEN의 발현율과 서로 상관관계가 있다.