• Journal of the Korean earth science society
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• v.22 no.1
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• pp.20-29
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• 2001

P wave traveltime delays has been measured and a preliminary tomouaphic inversion has been performed using the data collected from the network deployed by Korea National University of Education in the southcentral part Korea. The maximum variation in relative traveltime residuals is almost 0.7 seconds. A large azimuthal variation in traveltime residuals is observed at the stations in the northwestern part of the study area. This might indicate the existence of lateral velocity heterogeneity beneath the study area. Although, the inverted tomographic image seems to be correlated with the tectonic boundary between Kyunggi Massif and Okcheon Belt, the confidence level is presently low. We should place on the importance of this study for finding preferable inversion parameters and predicting probable result. Better tomographic image of the study area can be obtained in the near future when the data are accumulated.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1230-1231
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• 2008

The effect of content of $Al_2O_3+Y_2O_3$ sintering additives on the densification behavior, mechanical and electrical properties of the pressureless-sintered $SiC-ZrB_2$ electroconductive ceramic composites was investigated. The $SiC-ZrB_2$ electroconductive ceramic composites were pressureless-sintered for 2 hours at 1,700[$^{\circ}C$] temperatures with an addition of $Al_2O_3+Y_2O_3$(6:4 mixture of $Al_2O_3$ and $Y_2O_3$) as a sintering aid in the range of 8${\sim}$20[wt%]. Phase analysis of $SiC-ZrB_2$ composites by XRD revealed mostly of ${\alpha}$-SiC(6H), $ZrB_2$ and In Situ YAG($Al_5Y_3O_{12}$). The relative density, flexural strength, Young's modulus and vicker's hardness showed the highest value of 89.01[%], 81.58[Mpa], 31.437[GPa] and 1.34[GPa] for $SiC-ZrB_2$ composites added with 16[wt%] $Al_2O_3+Y_2O_3$ additives at room temperature respectively. Abnormal grain growth takes place during phase transformation from ${\beta}$-SiC into ${\alpha}$-SiC was correlated with In Situ YAG phase by reaction between $Al_2O_3$ and $Y_2O_3$ additive during sintering. Compositional design and optimization of processing parameters are key factors for controlling and improving the properties of SiC-based electroconductive ceramic composites. In this paper, it is convinced that ${\beta}$-SiC based electroconductive ceramic composites for heaters or ignitors can be manufactured by pressureless sintering.

• Geomechanics and Engineering
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• v.12 no.3
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• pp.441-464
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• 2017

The determination of the mixture parameters of stabilization has become a great concern in geotechnical applications. This paper presents an effort about the application of artificial intelligence (AI) techniques including radial basis neural network (RBNN), multi-layer perceptrons (MLP), generalized regression neural network (GRNN) and adaptive neuro-fuzzy inference system (ANFIS) in order to predict the unconfined compressive strength (UCS) of silty soil stabilized with bottom ash (BA), jute fiber (JF) and steel fiber (SF) under different freeze-thaw cycles (FTC). The dosages of the stabilizers and number of freeze-thaw cycles were employed as input (predictor) variables and the UCS values as output variable. For understanding the dominant parameter of the predictor variables on the UCS of stabilized soil, a sensitivity analysis has also been performed. The performance measures of root mean square error (RMSE), mean absolute error (MAE) and determination coefficient ($R^2$) were used for the evaluations of the prediction accuracy and applicability of the employed models. The results indicate that the predictions due to all AI techniques employed are significantly correlated with the measured UCS ($p{\leq}0.05$). They also perform better predictions than nonlinear regression (NLR) in terms of the performance measures. It is found from the model performances that RBNN approach within AI techniques yields the highest satisfactory results (RMSE = 55.4 kPa, MAE = 45.1 kPa, and $R^2=0.988$). The sensitivity analysis demonstrates that the JF inclusion within the input predictors is the most effective parameter on the UCS responses, followed by FTC.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.8
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• pp.3741-3745
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• 2014

Background: Emerging evidence implicates the platelet-derived growth factor-D (PDGF-D) in many types of human solid tumors. We investigated whether PDGF-D plays an important role in endometrial cancer (EC) in relation to clinicopathologic phenotype, angiogenesis, and patient prognosis. Materials and Methods: We analyzed PDGF-D protein expression by Western blotting in twenty-seven human endometrial cancer tissues, and matched normal endometrial controls collected at the third Affiliated hospital of Sun Yat-sen University during 2012-2013 (n=27). Immunohistochemical staining was performed using a human PDGF-D antibody on the endometrial cancer patients collected in the same facility during January 2001 and October 2013 (n=152). Patients were followed from the time of primary surgery in 2001-2013 until death or last follow-up. We correlated the PDGF-D expression levels with clinicopathologic parameters and prognosis in human endometrial cancer patients. Results: Compared with matched normal endometrial cases, PDGF-D was up-regulated in endometrial cancer. Expression of PDGF-D protein, found in 78% of the cases, was associated with nonendometrioid histologic type (p=0.028), FIGO stage III/IV (p=0.039), >50% solid tumor growth (p=0.048), pelvic LN metastasis (p=0.035) and ER and PR negativity (p=0.04 and 0.002). PDGF-D expression was also significantly associated with expression of VEGF-A (p=0.021). In multivariate analysis, PDGF-D expression proved to be an independent prognostic factor in addition to histologic grade and FIGO stage. Patients with high expression levels of PDGF-D had a significantly poorer overall survival rate compared with patients with no expression. Conclusions: PDGF-D expression is frequently up-regulated in endometrial cancer, and is associated with aggressive features and poor prognosis.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5651-5655
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• 2013

Objective: Major histocompatibility complex class I chain-related A (MICA) is a stress-inducible glycoprotein that can be shed as a soluble protein. This study was conducted to determine the expression of MICA in renal cell carcinoma (RCC) and examine the clinical relevance of soluble MICA (sMICA) in this disease. Methods: Immunohistochemistry and real-time PCR analyses were performed to assess the expression of MICA in 48 pairs of RCC and adjacent normal renal tissues. Serum levels of sMICA were measured in 48 RCC patients, 12 patients with benign renal tumors, and 20 healthy individuals. The correlations between sMICA levels and clinicopathological parameters were analyzed and the diagnostic performance of sMICA in RCC was evaluated. Results: RCCs exhibited elevated expression of MICA compared to adjacent normal tissues. Serum concentrations of sMICA were significantly greater in RCC patients ($348.5{\pm}32.5pg/ml$) than those with benign disease ($289.3{\pm}30.4pg/ml$) and healthy controls ($168.4{\pm}43.2pg/ml$) and significantly correlated with advanced tumor stage, lymph node metastasis, distant metastasis, vascular invasion, and higher histological grade. Using a cut-off point of 250 pg/ml, sMICA demonstrated a specificity and sensitivity of 63.2% and 75.6%, respectively, in distinguishing between RCC and benign renal tumors. Conclusion: MICA expression is upregulated in RCC and increased serum sMICA levels predict aggressive tumor behavior. However, the applicability of sMICA alone is limited in distinguishing RCC from benign renal tumors.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.10
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• pp.923-929
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• 2017

Generally, the sound emitted from a vehicle powered by an electric motor is lower than that of internal combustion engine vehicles. Therefore, pedestrians often cannot detect approaching electric vehicles. Therefore, a certain additional warning sound is required for these types of automobiles. In this study, to develop an audible warning sound, nine warning sounds are designed based on signal processing and chord theory. The background noise measured on the road is also added to these synthetic sounds. The detectability of these warning sounds is evaluated by subjective tests. The sound metric is correlated to detectability and is investigated through psychoacoustic theory and subjective evaluation. It is determined that known psychoacoustic parameters such as loudness, sharpness, and roughness have a low correlation with detectability. However, it is found that the interval of harmonic sound correlates well with detectability.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.5
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• pp.647-653
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• 2015

A 12-wk feeding trial was conducted to evaluate the essentiality of choline supplementation in diets for parrot fish. Five isonitrogenous and isocaloric diets were supplemented with 0 (as control), 500, 1,000, and 2,000 mg choline per kg diet, and a positive control diet without choline contained 0.3% of 2-amino-2-methyl-1-propanol as choline biosynthesis inhibitor (designated as Con, C500, C1000, C2000 and $Con^+$, respectively). Triplicate groups of fish (body weight, $8.8{\pm}0.01g$) were fed one of the experimental diets at a rate of 4% body weight twice daily. The fish fed $Con^+$ diet revealed significantly lower growth performance and feed utilization efficiency than other fish groups. Supplementation of choline to the basal diet did not significantly influence fish growth. The highest liver lipid content was observed in fish fed the $Con^+$ diet and inversely correlated with liver choline concentration although the differences were not significant. Also, significantly higher liver linoleic, eicosapentaenoic and docosahexaenoic acid contents were found in fish fed the $Con^+$ diet. Innate immune parameters including respiratory burst and myeloperoxidase activities were not significantly affected by dietary choline levels. The findings in this study conclude that choline concentration of approximately $230mgkg^{-1}$ diet meets the requirement of parrot fish.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2355-2362
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• 2012

The SH2B1 adaptor protein is recruited to multiple ligand-activated receptor tyrosine kinases that play important role in the physiologic and pathologic features of many cancers. The purpose of this study was to assess SH2B1 expression and to explore its contribution to the non-small cell lung cancer (NSCLC). Methods: SH2B1 expression in 114 primary NSCLC tissue specimens was analyzed by immunohistochemistry and correlated with clinicopathological parameters and patients' outcome. Additionally, 15 paired NSCLC background tissues, 5 NSCLC cell lines and a normal HBE cell line were evaluated for SH2B1 expression by RT-PCR and immunoblotting, immunofluorescence being applied for the cell lines. Results: SH2B1 was found to be overexpressed in NSCLC tissues and NSCLC cell lines. More importantly, high SH2B1 expression was significantly associated with tumor grade, tumor size, clinical stage, lymph node metastasis, and recurrence respectively. Survival analysis demonstrated that patients with high SH2B1 expression had both poorer disease-free survival and overall survival than other patients. Multivariate Cox regression analysis revealed that SH2B1 overexpression was an independent prognostic factor for patients with NSCLC. Conclusions: Our findings suggest that the SH2B1 protein may contribute to the malignant progression of NSCLC and could offer a novel prognostic indicator for patients with NSCLC.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.5
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• pp.2851-2857
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• 2013

Objective: REPS2 plays important roles in inhibiting cell proliferation, migration and in inducing apoptosis of cancer cells, now being identified as a useful biomarker for favorable prognosis in prostate and breast cancers. The purpose of this study was to assess REPS2 expression and to explore its role in esophageal squamous cell carcinoma (ESCC). Methods: Protein expression of REPS2 in ESCCs and adjacent non-cancerous tissues from 120 patients was analyzed by immunohistochemistry and correlated with clinicopathological parameters and patient outcome. Additionally, thirty paired ESCC tissues and four ESCC cell lines and one normal human esophageal epithelial cell line were evaluated for REPS2 mRNA and protein expression levels by quantitative RT-PCR and Western blotting. Results: REPS2 mRNA and protein expression levels were down-regulated in ESCC tissues and cell lines. Low protein levels were significantly associated with primary tumour, TNM stage, lymph node metastasis and recurrence (all, P < 0.05). Survival analysis demonstrated that decreased REPS2 expression was significantly associated with shorter overall survival and disease-free survival (both, P < 0.001), especially in early stage ESCC patients. When REPS2 expression and lymph node metastasis status were combined, patients with low REPS2 expression/lymph node (+) had both poorer overall and disease-free survival than others (both, P < 0.001). Cox multivariate regression analysis further revealed REPS2 to be an independent prognostic factor for ESCC patients. Conclusions: Our findings demonstrate that downregulation of REPS2 may contribute to malignant progression of ESCC and represent a novel prognostic marker and a potential therapeutic target for ESCC patients.

• Journal of Korean Neurosurgical Society
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• v.54 no.4
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• pp.280-288
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• 2013

Objective : Perfusion computed tomography (PCT) has the ability to measure quantitative value and produce maps of mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume (CBV). We assessed cerebral hemodynamics by using these parameters and acetazolamide (ACZ) challenge for pre- and post-procedural evaluation in patients with unilateral cerebrovascular stenotic disease. Methods : Thirty patients underwent pre-procedural PCT with ACZ challenge, and 24 patients (80%) was conducted follow up PCT after angioplasty with same protocol. The mean MTT, CBF, and CBV were measured and compared in both middle cerebral arterial (MCA) territories before and after ACZ challenge. Hemispheric ratio and percent change after ACZ challenge were calculated before and after angioplasty. Results : The mean stenosis rate was 76.6%. Significant increases in MTT (32.6%, p=0.000) and significant decreases in CBF (-14.2%, p=0.000) were found in stenotic side MCA territories. After ACZ challenge, there were significant changes in MTT (37.4%, p=0.000), CBF (-13.1%, p=0.000), and CBV (-10.5%, p=0.001) in pre-procedural perfusion study. However, no significant increases were found in MTT, or decreases in CBF and CBV in post-procedural study. There were no significant changes after ACZ challenge also. In addition, the degrees of these changes (before and after ACZ challenge) were highly correlated with the stenotic degrees in pre-procedural perfusion study. Conclusion : PCT with ACZ challenge appears to be a useful tool to assess the cerebral perfusion status especially in patients with unilateral symptomatic stenotic disease.