• Communications of the Korean Mathematical Society
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• v.27 no.4
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• pp.665-668
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• 2012

For a given graph G we consider a set S(G) of all symmetric matrices A = [$a_{ij}$] whose nonzero entries are placed according to the location of the edges of the graph, i.e., for $i{\neq}j$, $a_{ij}{\neq}0$ if and only if vertex $i$ is adjacent to vertex $j$. The minimum rank mr(G) of the graph G is defined to be the smallest rank of a matrix in S(G). In general the computation of mr(G) is complicated, and so is that of the maximum multiplicity MaxMult(G) of an eigenvalue of a matrix in S(G) which is equal to $n$ - mr(G) where n is the number of vertices in G. However, for trees T, there is a recursive formula to compute MaxMult(T). In this note we show that this recursive formula for MaxMult(T) also computes the path cover number $p$(T) of the tree T. This gives an alternative proof of the interesting result, MaxMult(T) = $p$(T).

• Journal of the Korean Society of Physical Medicine
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• v.9 no.1
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• pp.107-113
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• 2014

PURPOSE: The purpose of this study was to investigate the correlation between craniovertebral angle (CVA) and cardiorespiratory function ($VO_2max$ and $VCO_2max$) in young adults. METHODS: For this study, the students of D college were questioned and 50 members of D college were participated in our research.. Side-view pictures of each subject were taken in standing positions, in order to assess forward head posture (FHP) by measuring the craniovertebral angle. The craniovertebral angle was measured as the angle between a horizontal line at C7 and a line from the tragus of the ear to the spinous process of C7. And $VO_2max$ and $VCO_2max$ were measured by Quark CPET (cosmed co, USA) while the subjects were performed the treadmill running task of a intensity to set with respiratory mask. Subjucts were Then Pearson's correlation coefficient was calculated to estimate the relationship between craniovertebral and cardiorespiratory function ($VO_2max$ and $VCO_2max$) using SPSS for window. RESULTS: There was a significant positive correlation between craniovertebral angle and $VO_2max$ during treadmill running task (r=0.528, p<0.05). And there was a significant positive correlation between craniovertebral angle and $VO_2max$ during treadmill running task (r=0.566, p<0.05). CONCLUSION: Foreward head posture is related to cardiorespiratory function, and it has a negative correlation with cardiorespiratory function.

• Nonlinear Functional Analysis and Applications
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• v.27 no.4
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• pp.797-805
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• 2022

Let P(z) be a polynomial of degree n. A well-known inequality due to S. Bernstein states that if P ∈ P_n, then $$\max_{{\mid}z{\mid}=1}\,{\mid}P^{\prime}(z){\mid}\,{\leq}n\,\max_{{\mid}z{\mid}=1}\,{\mid}P(z){\mid}$$. In this paper, we establish some extensions and refinements of the above inequality to polar derivative and some other well-known inequalities concerning the polynomials and their ordinary derivatives.

• Korean Journal of Biological Psychiatry
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• v.3 no.2
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• pp.245-250
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• 1996

This research was performed to find out the changes of serotonin receptors in the platelet of alcoholics. Using $_{125}I-LSD$ as a radioligand. We obtained the following results. 1) In the comparison of patients vs controls, $B_{max}$ of the former was significantly higher than that of the latter(P=0.0017). But there was no significant difference in the Kd between the two groups. 2) In the comparison of type 1 vs type 2, alcoholics by cloninger's classification $B_{max}$ of the latter was significantly higher than that of the farmer(P=0.0396). But there was no significant difference in the Kd between the two groups. 3) In the comparison of alcohol abuse vs alcohol dependence, there were no significant differences in the value of $B_{max}$ and Kd between the two groups. These results support the hypothesis of serotonin-deficit in alcoholism. Furthermore, it can be inferred that the increase of platelet serotonin receptors in alcoholics might be used as a trait marker.

• Journal of the Korean GEO-environmental Society
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• v.13 no.4
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• pp.37-44
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• 2012

This study investigated on the adsorption of nonpoint pollution source using the Sand, hydroxyapatite(HAP), Zeolite and mixed culture. The adsorption of nonpoint pollution source on Sand, hydroxyapatite(HAP), Zeolite and mixed culture was investigated during a series of batch adsorption experiments. After the batch absorption experiments analysed COD, T-N, T-P on adsorption water. The experimental data was analysed using the pseudo-first-order adsorption kinetic models. Langmuir and Freundlich isotherm models were tested for their applicability. The maximum adsorbed amount $(Q_{max})$ of COD were found to be sand 0.0511mg/g, HAP 0.1905mg/g, Zeolite 1.0366mg/g and Mixed media 0.7444mg/g. The maximum adsorbed amount $(Q_{max})$ of T-N were found to be sand 0.0159mg/g, HAP 0.0537mg/g, Zeolite 0.5496mg/g and Mixed media 0.1374mg/g. The maximum adsorbed amount $(Q_{max})$ of T-P were found to be sand 0.0202mg/g, HAP 0.1342mg/g, Zeolite 0.0462mg/g and Mixed media 0.1180mg/g. As a result, the mixed media was effective to remove nonpoint pollution source.

• Korean Journal of Radiology
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• v.21 no.7
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• pp.829-837
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• 2020

Objective: The aim of this study was to investigate the prognostic value of the maximum standardized uptake value (SUV_max) measured while restaging with F-18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) to predict the 3-year post-recurrence survival (PRS) in patients with recurrent gastric cancer after curative surgical resection. Materials and Methods: In total, 47 patients with recurrent gastric cancer after curative resection who underwent restaging with ¹⁸F-FDG PET/CT were included. For the semiquantitative analysis, SUV_max was measured over the visually discernable ¹⁸F-FDG-avid recurrent lesions. Cox proportional-hazards regression models were used to predict the 3-year PRS. Differences in 3-year PRS were assessed with the Kaplan-Meier analysis. Results: Thirty-nine of the 47 patients (83%) expired within 3 years after recurrence in the median follow-up period of 30.3 months. In the multivariate analysis, SUV_max (p = 0.012), weight loss (p = 0.025), and neutrophil count (p = 0.006) were significant prognostic factors for 3-year PRS. The Kaplan-Meier curves demonstrated significantly poor 3-year PRS in patients with SUV_max > 5.1 than in those with SUV_max ≤ 5.1 (3-year PRS rate, 3.5% vs. 38.9%, p < 0.001). Conclusion: High SUV_max on restaging with ¹⁸F-FDG PET/CT is a poor prognostic factor for 3-year PRS. It may strengthen the role of ¹⁸F-FDG PET/CT in further stratifying the prognosis of recurrent gastric cancer.

• Journal of Life Science
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• v.13 no.1
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• pp.59-66
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• 2003

The bacterial strain was isolated from the 4th day's fermented Dolsan Leaf Mustard Kimchi(DLMK) at $20^{\circ}C$/TEX>. It was used as Kimchi starter, and then its physiological activity was investigated for 50 days at $4^{\circ}C$/TEX> and $10^{\circ}C$/TEX> The physiological activity of DLMK was examined for both antioxidative and Angiotensine Converting Enzyme(ACE) inhibitory activity. In the starter-inoculated DLMK(1 X $10^{10}$ CFU/mL) at 4 and $10^{\circ}C$, the optimal ripening period was more shortend than that of control(without starter) up to about 5.6 and 5 times, respectively. The maximal antioxidative activity in the starter-inoculated DLMK(1 X $10^{10}$ 10 CFU/mL) at 4 and $10^{\circ}C$ were 67% and 75%, respectively. The yield of cell concentration per day($lnX_{max}$/$t_{max}$) and the yield of antioxidative activity per day($P_{max}$/ｔ$t_{max}$) had a linear relationship. Also, the yield of antioxidative activity per day was increased with increasing the concentration of inoculated bacterium. By adding 1 X $10^{10}$ CFU/mL at 4 and $10^{\circ}C$, the ACE inhibitory activity of DLMK was maximal. The rates of inhibiting activities were 52% and 76%, respectively. Consequently, physiological activities were significantly affected by the inoculation concentrations of starter, but bacterium itself was not appeared the physiological activity. We assume that the bacterium metabolizes certain materials in DLMK and released compounds such as glucosinolates or its metabolized forms from DLMK show the antioxidative and ACE inhibitory activity.

• Journal of the Korean Chemical Society
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• v.54 no.6
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• pp.711-716
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• 2010

New electroluminescent polymers with fluoro groups in vinylene units, poly(m-silylphenyl-p-phenylene-difluorovinylene) (m-SiP-PPDFV) have been synthesized by GILCH polymerization. These polymers have been used as the electroluminescent (EL) layers in single layer light-emitting diodes (LEDs) (ITO/PEDOT/polymer/Ca:Al). m-SiP-PPDFV shows PL around $\lambda_{max}$ = 452 nm and green EL around $\lambda_{max}$ = 497 nm. The current-voltage-luminance (I-V-L) characteristics of the polymers show turn-on voltages of 4.0 V approximately. Two fluoro groups were introduced on every vinylene units of m-SiP-PPV to give m-SiP-PPDFV in an attempt to increase the electron affinity of the parent polymer, and the devices show an increased color stability even with vinylene units. The color stability is attributed to the electron-withdrawing effect of the fluoro groups, which protect vinylene units from oxidation in PPV derivatives. We believe that fluoro groups can be introduced in vinylene units in order to attain excellent stability of PPV derivatives.

• 한국체육학회지인문사회과학편
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• v.51 no.3
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• pp.373-382
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• 2012

The purpose of this study is to predict VO₂max with body index and submaximal metabolic responses. The subjects are consisted of 250 male aging from 18 to 34 and we separated them into two groups randomly; 179 for a sample, 71 for a cross-validation group. They went through maximal exercise testing with Bruce protocol, and we measured the metabolic responses in the end of the first(3 minute) and second stage(6 minute). To predict VO₂max, we applied multiple regression analysis to the sample with stepwise method. Model 1's variables are weight, 6 minute HR and 6 minute VO₂(R=0.64, SEE=4.74, CV=11.7%, p<.01), and the equation is VO₂max(ml/kg/min)= 72.256-0.340(Weight)-0.220(6minHR)+0.013(6minVO₂). Model 2's variables are weight, 6 minute HR, 6 minute VO₂, and 6 minute VCO₂(R=0.67, SEE=4.59, CV=11.3%, p<.01), and the equation is VO₂max(ml/kg/min)= 68.699-0.277(Weight) -0.206(6minHR)+0.020(6minVO₂)-0.009(6minVCO₂). And the result did not show multicolinearity for both models. Model 2 demonstrated more correlation compared to Model 1. However, when we conducted cross-validation of those models with 71 men, measured VO₂max and estimated VO₂ Max had statistical significance with correlation (R=0.53, 0.56, P<.01). Although both models are functional with validity considering their simplicity and utility, Model 2 has more accuracy.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.3
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• pp.169-176
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• 2006

Purpose: According to the development of CT scanner in PET/CT system, the role of CT unit as a diagnostic tool has been more important. To improve the diagnostic ability of CT scanner, it is a key aspect that CT scanning has to be performed with high dose energy and intravenous (IV) contrast. So we investigated the effect of IV contrast media on the maximum SUV (maxSUV) of normal tissues and pathologic lesions using PET/CT scanner with high dose CT scanning. Materials & Methods: The study enrolled 13 patients who required PET/CT evaluation. At first, the patients were performed whole body non-contrast CT (NCCT-120 kVp, 130 mAs) scan. Then contrast enhanced CT (CECT) scan was performed immediately. Finally PET scan was followed. The PET omission data were reconstructed twice, once with the NCCT and again with the CECT. We measured the maxSUV of 10 different body regions that were considered as normal in ail patients. Also pathologic lesions were investigated. Results: There were not seen focal artifacts in PET images based on CT with IV contrast agent. Firstly, 130 normal regions in 13 patients were evaluated. The maxSUV was significantly different between two PET images (p<0.00)). The maxSUV was $1.1{\pm}0.5$ in PET images with CECT-corrected attenuation and $1.0{\pm}0.5$ in PET images with NCCI-corrected attenuation. The limit of agreement was $0.1{\pm}0.3$ in Bland-Altman analysis. Especially there were significant differences in 6 of 10 regions, apex and base of the right lung, ascending aorta, segment 6 & segment 8 of the liver and spleen (p<0.05). Secondly, 39 pathologic lesions were evaluated. The maxSUV was significantly different between two PET images (p<0.001). The maxSUV was $4.7{\pm}2.0$ in PET images with CECT-corrected attenuation and $4.4{\pm}2.0$ in PET images with NCCT-corrected attenuation. The limit of agreement was $0.4{\pm}0.8$ in Bland-Altman analysis. Conclusion: Although there were increases of maxSUVs in the PET images based on CT with IV contrast agent, it was very narrow in the range of limit of agreement. So there was no significant effect to clinical interpretation for PET images that were corrected attenuation with high dose CT using IV contrast.