• The Korean Journal of Applied Statistics
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• v.30 no.5
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• pp.775-791
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• 2017

We frequently encounter binary data in real life. Logistic, Probit, Cauchit, Complementary log-log models are often used for binary data analysis. In order to analyze binary data, Liu (2004) proposed a Robit model, in which the inverse of cdf of the Student's t distribution is used as a link function. Kim et al. (2008) also proposed a generalized t-link model to make the binary regression model more flexible. The more flexible skewed distributions allow more flexible link functions in generalized linear models. In the sense, we propose a binary data regression model using skewed generalized t distributions introduced in Theodossiou (1998). We implement R code of the proposed models using the glm function included in R base and R sgt package. We also analyze Pima Indian data using the proposed model in R.

• Animal cells and systems
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• v.3 no.3
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• pp.275-283
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• 1999

Korean R. plancyi occupies a restricted area in western South Korea and shows a relatively low level of genic variability (%P＝15.2, Ho=0.052, He＝0.048). In contrast, R. nigromaculata is broadly distributed in South Korea. The observed low level of variability of R. nigromaculata (%P＝14.3, Ho＝0.042, He＝0.043) is probably due to its recent colonization. Populations of R. nigromaculata exhibited considerable genetic differentiation (F$_{sT}$=0.149) and low level of gene flow (Nm＝1.427) among populations, compared to those of R. Plancyi (F$_{sTF$_{sT}$}$=0.096, Nm＝2.354), which occupies a restricted area. The observed levels of gene flow among populations of R. nigromaculata (Nm＝1.427) over a broad geographic range is relatively higher than other amphibian species. The high level of gene flow is probably the result of the high dispersal abilities of R. nigromaculata. A survey of temporal genic variation of R. nigromaculata showed that there was no significant change on the overall average genetic diversity from 1978 (average He＝0.044) to 1997 (average He＝0.040). Wright's F-statistics also indicated no significant genetic differentiation from 1978 (F$_{sT}$＝0.118) to 1997 (F$_{sT}$＝0.108). This suggests that the environmental change appears to have had little influence on the genetic composition of R. nigromaculata in the study areas during the past 20 years. The low level of temporal variation might be due to the result of high dispersal abilities and wide migration range of this species.

• Bulletin of the Korean Mathematical Society
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• v.46 no.3
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• pp.599-605
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• 2009

Let R be a prime ring, H a generalized derivation of R and L a noncommutative Lie ideal of R. Suppose that $u^sH(u)u^t$ = 0 for all u $\in$ L, where s $\geq$ 0, t $\geq$ 0 are fixed integers. Then H(x) = 0 for all x $\in$ R unless char R = 2 and R satisfies $S_4$, the standard identity in four variables.

• The Journal of Internal Korean Medicine
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• v.35 no.4
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• pp.416-427
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• 2014

Objectives: The purpose of this study was to investigate the antineoplastic effect of several herbal medicine mixtures (compositions of Astragalus membranaceu, Angelica gigas, Trichosanthes kirilowii, Panax ginseng, Rhus verniciflua Stokes) on the SNU-80 anaplastic thyroid carcinoma cell line. Methods: MTT assay was used to examine whether our herbal medicine mixtures decreased cell growth rate of SNU-80. Wound healing assay and Transwell invasion assay was performed to investigate whether our herbal medicine mixtures affect the migration and invasion of anaplastic cancer cells, SNU-80. ELISA assay was performed to know if our herbal medicine mixtures suppressed the expression of pro-invasive molecules, such as vascular endothelial growth factor (VEGF) and matrix metalloproteinase-2 (MMP-2) secreted from SNU-80. Results: MTT assay demonstrated that A. membranaceus:A. gigas:T. kirilowii=1:1:1 or 3:1:1, A. membranaceus:A. gigas :T. kirilowii:P. ginseng=1:1:1:1 or 3:1:1:1, A. membranaceus:A. gigas:T. kirilowii:P. ginseng:R. verniciflua Stokes=1:1:1:1:1 or 3:1:1:1:1 strongly suppressed the growth of SNU-80. Wound healing assay demonstrated that A. membranaceus:A. gigas=3:1, A. membranaceus:A. gigas:T. kirilowii=1:1:1 or 3:1:1, A. membranaceus:A. gigas:T. kirilowii:P. ginseng=1:1:1:1 or 3:1:1:1, A. membranaceus:A. gigas:T. kirilowii:P. ginseng:R. verniciflua Stokes=1:1:1:1:1 or 3:1:1:1:1 inhibited the migration of SNU-80. Transwell invasion assay demonstrated that A. membranaceus:A. gigas=1:1, A. membranaceus:A. gigas:T. kirilowii =1:1:1 or 3:1:1, A. membranaceus:A. gigas:T. kirilowii:P. ginseng=1:1:1:1, A. membranaceus:A. gigas:T. kirilowii:P. ginseng :R. verniciflua Stokes=1:1:1:1:1 or 3:1:1:1:1 inhibited the invasion of SNU-80. ELISA assay demonstrated that A. membranaceus :A. gigas:T. kirilowii=1:1:1 or 3:1:1, A. membranaceus:A. gigas:T. kirilowii:P. ginseng:R. verniciflua Stokes=1:1:1:1:1 suppressed the expression of VEGF. Also, A. membranaceus:A. gigas=1:1, A. membranaceus:A. gigas:T. kirilowii=1:1:1 or 3:1:1, A. membranaceus :A. gigas:T. kirilowii:P. ginseng=1:1:1:1 or 3:1:1:1, A. membranaceus:A. gigas:T. kirilowii:P. ginseng:R. verniciflua Stokes =1:1:1:1:1 or 3:1:1:1:1 suppressed the expression of MMP-2. Conclusions: The results obtained in this study suggest that several herbal medicine mixtures suppresse the growth and inhibit the migration and invasion of SNU-80, which is anaplastic thyroid cancer cells. Especially, A. membranaceus:A. gigas: T. kirilowii=1:1:1 mixture had a stronger anti-cancer effect.

• Journal of Korea Foundry Society
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• v.33 no.1
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• pp.13-21
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• 2013

The effects of rare earth element (R.E.) and cooling rate on the eutectic reaction of flake graphite cast irons were studied by combined analysis of macro/micro-structure and cooling curve data. The correlation between eutectic reaction parameter and macro/micro-structure was systematically investigated. Two sets of chemical compositions with the different addition of R.E. were designed to cast. Three types of molds for cylindrical specimens with the different diameters were prepared to analyze cooling rate effect. The difference between undercooling temperature and cementite eutectic temperature (${\Delta}T_1=T_{U}-T_{E,C}$), which is increased by adding R.E. and decreased by increasing cooling rate, is considered to be a suitable eutectic reaction parameter for predicting graphite morphology. According to the criterion, A-type graphite is mainly suggested to form for ${\Delta}T_1$ over $20^{\circ}C$. Eutectic reaction time (${\Delta}t$), which is decreased by adding R.E. or increasing cooling rate, is a suitable eutectic reaction parameter for predicting eutectic cell size. Eutectic cell size is found to decrease in a proportion to the decrease of ${\Delta}t$.

• The Korean Journal of Nuclear Medicine
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• v.19 no.1
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• pp.103-111
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• 1985

Recently changes in thyroid physiology during acute and chronic medical illness were demonstrated. The serum $fT_3,\;rT_3,\;T_4,\;T_3,\;fT_4$, and TSH concentration were measured by radioimmunoassay method in 49 patients with critical illness and 10 normal subjects to assess the change of thyroid function in critical illness. The results were as follows; 1) The mean serum $fT_3$ concentration was $6.68{\pm}1.05pmol/ml$ in normal subjects while in patients with critical illness the serum $fT_3$ concentration was significantly lowered to $1.55{\pm}1.15pmol/ml$(p<0.001). 2) The mean serum $rT_3$ concentration was $0.22{\pm}0.44ng/ml$ in normal subjects and $0.42{\pm}0.37ng/ml$ in patient with critical illness. There was increment in critically ill patients as compared to normal subjects but no statistically significant difference(p>0.05). 3) The mean serum $T_3$ concentration was $1.24{\pm}0.25ng/ml$ in normal subjects and $0.56{\pm}0.56ng/ml$ in patients with criticial illness and there was significant difference in each other(p<0.005). 4) The mean serum $T_4,\;fT_4$, and TSH concentrations were $7.80{\pm}1.02{\mu}g/dl,\;1.26{\pm}0.39ng/dl,\;1.87{\pm}0.45{\mu}U/ml$ in normal subjects respectively and $6.02{\pm}3.06{\mu}g/dl,\;1.46{\pm}0.80ng/dl,\;1.74{\pm}0.79{\mu}U/ml$ in patients with critical illness and there was no significant difference between critically ill patients and normal subjects. 5) The ratio of mean serum concentration of $fT_3$ and $rT_3(fT_3/rT_3)$, $30.42{\pm}5.58$ in normal subjects was significantly higher(p<0.005) than the coresponding patients with critical illness. 6) The mean serum $fT_3$ concentration in expired cases(n=12) during admission was significant difference between expired and survived cases(p<0.005). The mean serum $rT_3$ centration was $0.67{\pm}0.58ng/ml$ in expired cases and $0.34{\pm}0.22ng/ml$ in survived cases with significant difference(p<0.005). Half of the cases who showed less than $3{\mu}g/dl$ of serum $T_4$ level were expired.

• Korean Journal of Mathematics
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• v.20 no.2
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• pp.177-184
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• 2012

In this paper, we study the four different types of relations, $\mathcal{P}(X,T)$, $\mathcal{R}(X,T)$, $\mathcal{L}(X,T)$, and $\mathcal{S}(X,T)$ in a transformation (X,T), and obtain some of their properties. In particular, we give a relationship between $\mathcal{R}(X,T)$ and $\mathcal{S}(X,T)$.

• Journal of the Korean Data and Information Science Society
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• v.10 no.1
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• pp.111-118
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• 1999

We treat the problem of estimating reliability R(t) = P[Y(t) < X(t)] in the time dependent strength-stress model in which a unit of strength X(t) is subjected to environmental stress Y(t) at time t. In this paper two nonparametric approaches to estimate of R(t) are analyzed and compared with parametric method by simulation.

• Nutrition Research and Practice
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• v.3 no.1
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• pp.3-8
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• 2009

The matrix metalloproteinases (MMP) play an important role in tumor invasion, angiogenesis and inflammatory tissue destruction. Increased expression of MMP was observed in benign tissue hyperplasia and in atherosclerotic lesions. Invasive cancer cells utilize MMP to degrade the extracellular matrix and vascular basement membrane during metastasis, where MMP-2 has been implicated in the development and dissemination of malignancies. The present study attempted to examine the antiangiogenic activity of the medicinal herbs of Aspergillus usamii var. shirousamii-transformed Angelicae Gigantis Radix and Zizyphus jujube (tAgR and tZj) with respect to MMP-2 production and endothelial motility in phorbol 12-myristate 13-acetate (PMA)- or VEGF-exposed human umbilical vein endothelial cells (HUVEC). Nontoxic tAgR and tZj substantially suppressed PMA-induced MMP-2 secretion. In addition, $25{\mu}g/mL$ tAgR and tZj prevented vascular endothelial growth factor-stimulated endothelial cell transmigration and tube formation. The results reveal that tAgR and tZj dampened endothelial MMP-2 production leading to endothelial transmigration and tube formation. tAgR and tZj-mediated inhibition of endothelial MMP may boost a therapeutic efficacy during vascular angiogenesis.

• Journal of Gastric Cancer
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• v.16 no.4
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• pp.207-214
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• 2016

Purpose: The utility of N classification has been questioned after the 7th edition of the American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) was published. We evaluated the correlation between ratio-based N (rN) classification with the overall survival of pathological T4 gastric cancer patients who underwent D2 lymphadenectomy. Materials and Methods: We reviewed 222 cases of advanced gastric cancer patients who underwent curative gastrectomy between January 2006 and December 2015. The T4 gastric cancer patents were classified into four groups according to the lymph node ratio (the number of metastatic lymph nodes divided by the retrieved lymph nodes): rN0, 0%; rN1, ${\leq}13.3%$; rN2, ${\leq}40.0%$; and rN3, >40.0%. Results: The rN stage showed a large down stage migration compared with pathological T4N3 (AJCC/UICC). There was a significant difference in overall survival between rN2 and rN3 groups in patients with pT4N3 (P=0.013). In contrast, the difference in metastatic lymph nodes was not significant in these patients (${\geq}16$ vs. <15; P=0.177). In addition, the rN staging system showed a more distinct difference in overall survival than the pN staging system for pathological T4 gastric cancer patients. Conclusions: Our results confirm that rN staging could be a good alternative for pathological T4 gastric cancer patients who undergo D2 lymphadenectomy. However, before applying this system to gastric cancer patients who undergo D2 lymphadenectomy, a larger sample size is required to further evaluate the usefulness of the rN staging system for all stages, including less advanced stages.