Setting Considerations of Distance Relay for Transmission Line with STATCOM

Wen-Hao Zhang,Seung-Jae Lee,Myeon-Song Choi 대한전기학회 2010 Journal of Electrical Engineering & Technology Vol.5 No.4

Distance relay plays an important role in the protection of transmission lines. The application of flexible AC transmission systems (FACTS) devices, such as the static synchronous compensator (STATCOM), could affect the performance of the distance relay because of compensation effect. This paper analyzes the application of distance relay on the protection of a transmission line containing STATCOM. New setting principles for different protection zones are proposed based on this analysis. A typical 500 kV transmission system employing STATCOM is modeled using Matlab/Simulink. The impact of STATCOM on distance protection scheme is studied for different fault types, fault locations, and system configurations. Based on simulation results, the performance of distance relay is evaluated. The setting principle can be verified for the transmission line with STATCOM.

Preferential Induction of CYP1A1 over CYP1B1 in Human Breast Cancer MCF-7 Cells after Exposure to Berberine

Wen, Chun-Jie,Wu, Lan-Xiang,Fu, Li-Juan,Shen, Dong-Ya,Zhang, Xue,Zhang, Yi-Wen,Yu, Jing,Zhou, Hong-Hao Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.1

Estrogens are considered the major breast cancer risk factor, and the carcinogenic potential of estrogens might be attributed to DNA modification caused by derivatives formed during metabolism. $17{\beta}$-estradiol ($E_2$), the main steroidal estrogen present in women, is metabolized via two major pathways: formation of 2-hydroxyestradiol (2-OH $E_2$) and 4-hydroxyestradiol ($4-OH\;E_2$) through the action of cytochrome P450 (CYP) 1A1 and 1B1, respectively. Previous reports suggested that $2-OH\;E_2$ has putative protective effects, while $4-OH\;E_2$ is genotoxic and has potent carcinogenic activity. Thus, the ratio of $2-OH\;E_2/4-OH\;E_2$ is a critical determinant of the toxicity of $E_2$ in mammary cells. In the present study, we investigated the effects of berberine on the expression profile of the estrogen metabolizing enzymes CYP1A1 and CYP1B1 in breast cancer MCF-7 cells. Berberine treatment produced significant induction of both forms at the level of mRNA expression, but with increased doses produced 16~ to 52~fold greater induction of CYP1A1 mRNA over CYP1B1 mRNA. Furthermore, berberine dramatically increased CYP1A1 protein levels but did not influence CYP1B1 protein levels in MCF-7 cells. In conclusion, we present the first report to show that berberine may provide protection against breast cancer by altering the ratio of CYP1A1/CYP1B1, could redirect $E_2$ metabolism in a more protective pathway in breast cancer MCF-7 cells.

Evaluation of Liver Metastases Using Contrast-Enhanced Ultrasound: Enhancement Patterns and Influencing Factors

( Wen Tao Kong ),( Zheng Biao Ji ),( Wen Ping Wang ),( Hao Cai ),( Bei Jian Huang ),( Hong Ding ) 대한소화기학회 2016 Gut and Liver Vol.10 No.2

Background/Aims: To evaluate the enhancement patterns of liver metastases and their influencing factors using dynamic contrast-enhanced ultrasound (CEUS). Methods: A total of 240 patients (139 male and 101 female; 58.5±11.2 years of age) diagnosed with liver metastases in our hospital were enrolled in this study to evaluate tumor characteristics using CEUS. A comparison of enhancement patterns with tumor size and primary tumor type was performed using the chi-square test. The differences between quantitative variables were evaluated with the independent-sample t-test and one-way analysis of variance. Results: The enhancement patterns of liver metastases on CEUS were categorized as diffuse homogeneous hyperenhancement (133/240, 55.4%), rim-like hyperenhancement (80/240, 33.3%), heterogeneous hyperenhancement (10/240, 4.2%), and isoenhancement (17/240, 7.1%). There were significant differences in the enhancement patterns during the arterial phase based on the nodule size (p=0.001). A total of 231 of the nodules showed complete washout during the portal phase, and 237 nodules were hypoenhanced during the delayed phase. The washout time was correlated with tumor vascularity, with a longer washout time observed in hypervascular metastases compared to hypovascular metastases (p=0.033). Conclusions: Diffuse homogeneous hyperenhancement followed by rapid washout was the most common enhancement pattern of liver metastases on CEUS and was affected by the nodule size and tumor vascularity. Small metastases were prone to show diffuse homogeneous hyperenhancement. Hypervascular metastases showed a significantly longer washout time compared to hypovascular metastases. (Gut Liver 2016;10:283-287)

User-intervened structured meshing methods and applications for complex flow fields based on multiblock partitioning

Wen-Hao Cai,Jie-Min Zhan,Ying-Ying Luo 한국CDE학회 2021 Journal of computational design and engineering Vol.8 No.1

Recently, a series of automatic structured grid generation methods for different fields or specific problems have been proposed by various researchers, but these methods still have some disadvantages or limitations. Therefore, in the present study, several user-intervened structured meshing methods for complex flow fields have been introduced for multiblock docking and multiblock splicing based on multiblock structured grid technology. Besides, three applications compared with the other methods or experiments are discussed to illustrate the crucial workflow of the user-intervened partitioning. The successful implementation of these partitioning examples demonstrates the feasibility and effectiveness of the methods described herein. And the techniques and criteria summarized in the present paper are quite practical and helpful for high-quality meshing.

Isolation of cutaneous resident dendritic cells and their role for inducing T cell-driven Th17 chemokine CCL20 in vitro

( Wen Hao Wu ),( Tae Gyun Kim ),( Do Young Kim ),( Hyun Joong Jee ),( Dashlkhumbe Byamba ),( Min Geol Lee ) 대한피부과학회 2011 초록집 Vol.49 No.20

A Probabilistic Method Based Protectability Evaluation of Distance Relay in Transmission Networks

Wen-Hao Zhang,Myeon-Song Choi,Seung-Jae Lee,Il-Hyung Lim,Seong-Jeong Rim 대한전기학회 2008 Journal of Electrical Engineering & Technology Vol.3 No.3

This paper defines the concept of "protectability" for the performance evaluation of distance relay considering its sensitivity and selectivity. The paper starts from the probabilistic modeling of the errors, and based on this model, a detailed explanation of protectability calculation for each zone of the distance relay is presented. An effect of the Weighting Rate and the Measurement Deviation on the protectability evaluation is also given. By considering this effect, the optimization of relay setting can be realized. The proposed method is applied to a typical model system to show its effectiveness

A Robust Fault Location Algorithm for Single Line-to-ground Fault in Double-circuit Transmission Systems

Wen-Hao Zhang,Umar Rosadi,Myeon-Song Choi,Seung-Jae Lee,Ilhyung Lim 대한전기학회 2011 Journal of Electrical Engineering & Technology Vol.6 No.1

This paper proposes an enhanced noise robust algorithm for fault location on double-circuit transmission line for the case of single line-to-ground (SLG) fault, which uses distributed parameter line model that also considers the mutual coupling effect. The proposed algorithm requires the voltages and currents from single-terminal data only and does not require adjacent circuit current data. The fault distance can be simply determined by solving a second-order polynomial equation, which is achieved directly through the analysis of the circuit. The algorithm, which employs the faulted phase network and zero-sequence network with source impedance involved, effectively eliminates the effect of load flow and fault resistance on the accuracy of fault location. The proposed algorithm is tested using MATLAB/Simulink under different fault locations and shows high accuracy. The uncertainty of source impedance and the measurement errors are also included in the simulation and shows that the algorithm has high robustness.

Genomic Screening for Targets Regulated by Berberine in Breast Cancer Cells

Wen, Chun-Jie,Wu, Lan-Xiang,Fu, Li-Juan,Yu, Jing,Zhang, Yi-Wen,Zhang, Xue,Zhou, Hong-Hao Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.10

Berberine, a common isoquinoline alkaloid, has been shown to possess anti-cancer activities. However, the underlying molecular mechanisms are still not completely understood. In the current study, we investigated the effects of berberine on cell growth, colony formation, cell cycle distribution, and whether it improved the anticancer efficiency of cisplatin and doxorubicin in human breast cancer estrogen receptor positive (ER+) MCF-7 cells and estrogen receptor negative (ER-) MDA-MB-231 cells. Notably, berberine treatment significantly inhibited cell growth and colony formation in the two cell lines, berberine in combination with cisplatin exerting synergistic growth inhibitory effects. Accompanied by decreased growth, berberine induced G1 phase arrest in MCF-7 but not MDA-MB-231 cells. To provide a more detailed understanding of the mechanisms of action of berberine, we performed genome-wide expression profiling of berberine-treated cells using cDNA microarrays. This revealed that there were 3,397 and 2,706 genes regulated by berberine in MCF-7 and MDA-MB-231 cells, respectively. Fene oncology (GO) analysis identified that many of the target genes were involved in regulation of the cell cycle, cell migration, apoptosis, and drug responses. To confirm the microarray data, qPCR analysis was conducted for 10 selected genes based on previously reported associations with breast cancer and GO analysis. In conclusion, berberine exhibits inhibitory effects on breast cancer cells proliferation, which is likely mediated by alteration of gene expression profiles.

Development and Validation of Nomograms to Provide Individualized Predictions of Sur-vival Benefits from Surgery in Patients with Intermediate/Advanced Hepatocel-lular Carcinoma

( Wen-tao Yan ),( Jia-he Wang ),( Ming-da Wang ),( Zheng Wang ),( Bing Quan ),( Ya-hao Zhou ),( Wei-min Gu ),( Hong Wang ),( Ting-hao Chen ),( Tian Yang ) 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: According to the BCLC treatment guidelines, surgery does not be recommended for intermediate/advanced hepatocellular carcinoma (HCC). In real world, however, liver resections are often performed in patients with intermediate/ advanced but resectable HCC, especially in the East. Methods: We retrospectively evaluated multicentric data of 1,325 patients newly diagnosed with intermediate/advanced HCC who underwent curative resection. We randomly divided the subjects into development (n = 875) and validation (n = 450) samples. Multivariate Cox proportional hazards models were developed and separately validated on the basis of patients’ clinicopathological variables assessed for associations with 1-year recurrence and 3-year mortality. The discriminatory accuracy of these models was compared with conventional tools by analyzing receiver operating characteristic (ROC) curves. Results: He statistical nomograms built based on performance status, Child-Pugh grade, portal hypertension, preoperative alpha-fetoprotein level, tumor rupture, largest tumor diameter, tumor number, macrovascular and microvascular invasion, and satellites had good calibration and discriminatory abilities, with c-indices of 0.70 (1-year recurrence) and 0.68 (3-year survival), respectively. These models showed satisfactory goodness-of-fit and discrimination abilities in the validation cohort (c-index, 0.68 for 1-year recurrence and 0.69 for 3-year survival). The areas under the ROC curve using these nomograms exceeded those of traditional staging systems, indicating superior discriminatory capability (c-indices, 0.60-0.63 and 0.56-0.62, respectively). Conclusions: Our proposed online nomograms, which present graphically postoperative prognostic models for recurrence and survival in patients with intermediate/advanced but resectable HCC, offer valuable guidance to surgeons and hepatologists for individually predicting survival benefits from surgery and planning recurrence surveillance and adjuvant therapy.

Early Diagnosis and Management of Cerebral Venous Flow Obstruction Secondary to Transsinus Fracture after Traumatic Brain Injury

Wen-hao Wang,Jun-ming Lin,Fei Luo,Lian-shui Hu,Jun Li,Wei Huang 대한신경과학회 2013 Journal of Clinical Neurology Vol.9 No.4

Background and Purpose Cerebral venous flow obstruction (CVFO) is a fatal complication of traumatic brain injury. To compare the outcomes of patients with CVFO secondary to traumatic-brain-injury-induced transsinus fracture who were diagnosed early versus those diagnosed late in the therapeutic course. Methods In total, 403 patients with transsinus fracture were reviewed retrospectively. The patients were divided into an early-diagnosis group (n=338) and a delayed-diagnosis group (n=65).The patients submitted to 2D time-of-flight magnetic resonance venography (2D-TOF MRV) and/or CT venography (CTV), depending upon the findings of intracranial pressure monitoring, in order to identify potentially complicated CVFO. These examinations took place within 3 days of the onset of malignant intracranial hypertension symptoms in the early-diagnosis group, and after an average of 7 days in the delayed-diagnosis group. Once diagnosed, patients received intravenous thrombolytic therapy with low-dose urokinase. Patients with massive transsinus epidural hematoma, depressed fracture, or cerebral hernia were treated surgically to relieve the compression and repair any damage to the venous sinuses. Results Cerebral venous flow obstruction was much more severe in the delayed-diagnosis group than in the early-diagnosis group (p<0.001), and hence patients in the former group were given a higher dose of urokinase (p<0.001) for thrombolytic therapy. They were also significantly more likely to need surgery (48.1% vs. 20.6%, p=0.003) and had a higher mortality rate (37.0%vs. 4.1%, p<0.001). However, patients in both groups experienced a similarly favorable prognosis, not only with regard to functional outcome but also with respect to neuroradiological improvement, as evaluated by 2D-TOF MRV/CTV at the final follow-up (p=0.218). Conclusions Delayed diagnosis can result in increased risk of surgery and death in the acute phase. Thrombolytic therapy with low-dose urokinase resulted in promising improvements in both functional and neuroradiological outcomes in all of the patients in this study, regardless of the time to diagnosis. J Clin Neurol 2013;9:259-268