• Korean Journal of Radiology
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• v.20 no.4
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• pp.621-630
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• 2019

Objective: To study the prevalence and clinical characteristics of decreased myocardial blood flow (MBF) quantified by dynamic computed tomography (CT) myocardial perfusion imaging (MPI) in symptomatic patients without in-stent restenosis. Materials and Methods: Thirty-seven (mean age, 71.3 ± 10 years; age range, 48-88 years; 31 males, 6 females) consecutive symptomatic patients with patent coronary stents and without obstructive de novo lesions were prospectively enrolled to undergo dynamic CT-MPI using a third-generation dual-source CT scanner. The shuttle-mode acquisition technique was used to image the complete left ventricle. A bolus of contrast media (50 mL; iopromide, 370 mg iodine/mL) was injected into the antecubital vein at a rate of 6 mL/s, followed by a 40-mL saline flush. The mean MBF value and other quantitative parameters were measured for each segment of both stented-vessel territories and reference territories. The MBF_ratio was defined as the ratio of the mean MBF value of the whole stent-vessel territory to that of the whole reference territory. An MBF_ratio of 0.85 was used as the cut-off value to distinguish hypoperfused from non-hypoperfused segments. Results: A total of 629 segments of 37 patients were ultimately included for analysis. The mean effective dose of dynamic CT-MPI was 3.1 ± 1.2 mSv (range, 1.7-6.3 mSv). The mean MBF of stent-vessel territories was decreased in 19 lesions and 81 segments. Compared to stent-vessel territories without hypoperfusion, the mean MBF and myocardial blood volume were markedly lower in hypoperfused stent-vessel territories (77.5 ± 16.6 mL/100 mL/min vs. 140.4 ± 24.1 mL/100 mL/min [p < 0.001] and 6.4 ± 3.7 mL/100 mL vs. 11.5 ± 4 mL/100 mL [p < 0.001, respectively]). Myocardial hypoperfusion in stentvessel territories was present in 48.6% (18/37) of patients. None of clinical parameters differed statistically significantly between hypoperfusion and non-hypoperfusion subgroups. Conclusion: Decreased MBF is commonly present in patients who are symptomatic after percutaneous coronary intervention, despite patent stents and can be detected by dynamic CT-MPI using a low radiation dose.

• Korean Journal of Radiology
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• v.20 no.5
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• pp.709-718
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• 2019

Objective: To investigate the association of myocardial blood flow (MBF) quantified by dynamic computed tomography (CT) myocardial perfusion imaging (MPI) with troponin level and left ventricle (LV) function in patients with ST-segment elevated myocardial infarction (STEMI). Materials and Methods: Thirty-five STEMI patients who successfully had undergone reperfusion treatment within 1 week of their infarction were consecutively enrolled. All patients were referred for dynamic CT-MPI. Serial high-sensitivity troponin T (hs-TnT) levels and left ventricular ejection fraction (LVEF) measured by echocardiography were recorded. Twenty-six patients with 427 segments were included for analysis. Various quantitative parameters derived from dynamic CT-MPI were analyzed to determine if there was a correlation between hs-TnT levels and LVEF on admission and again at the 6-month mark. Results: The mean radiation dose for dynamic CT-MPI was 3.2 ± 1.1 mSv. Infarcted territories had significantly lower MBF (30.5 ± 7.4 mL/min/100 mL versus 73.4 ± 8.1 mL/min/100 mL, p < 0.001) and myocardial blood volume (MBV) (2.8 ± 0.9 mL/100 mL versus 4.2 ± 1.1 mL/100 mL, p = 0.044) compared with those of reference territories. MBF showed the best correlation with the level of peak hs-TnT (r = -0.682, p < 0.001), and MBV showed a moderate correlation with the level of peak hs-TnT (r = -0.437, p = 0.026); however, the other parameters did not show any significant correlation with hs-TnT levels. As for the association with LV function, only MBF was significantly correlated with LVEF at the time of admission (r = 0.469, p = 0.016) and at 6 months (r = 0.585, p = 0.001). Conclusion: MBF quantified by dynamic CT-MPI is significantly inversely correlated with the level of peak hs-TnT. In addition, patients with lower MBF tended to have impaired LV function at the time of their admission and at 6 months.

• Geotechnical Engineering
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• v.12 no.6
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• pp.79-86
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• 1996

This study develops a new method for interpreting the yield load from load tests on drilled shaft foundations ended on general soils, which is defined as a point where the maximum curvature on the hyperbolic-approximated load-settlement curve occurs. How ever, the point of maximum curvature is a variable depending on the units and scales of the load and settlement. Therefore, to obtain a unique maximum curvature point, both the load and settlement must be normalized by proper parameters, respectively, and be expressed on the same scaled arses(1:1). Normalization has been processed so that the yield load by the new interpretation is to be close to the average of yield loads interpreted by other methods investigated in this study. The quantitative comparison between the new criterion and other conventitonal methods is presented.

• Journal of Digital Convergence
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• v.11 no.2
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• pp.175-182
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• 2013

In this paper, the simulation model of house price is presented on the basis of pricing mechanism between the demand and the supply of apartments in seoul. The algorithm of house price simulation model for calculating the rate of price over time includes feedback control theory. The feedback control theory consists of stock variable, flow variable, auxiliary variable and constant variable. We suggest that the future price of apartment is simulated using mutual interaction variables which are demand, supply, price and parameters among them. In this paper we considers three items which include the behavior of apartment price index, the size of demand and supply, and the forecasting of the apartment price in the future economic scenarios. The proposed price simulation model could be used in public needs for developing a house price regulation policy using financial and non-financial aids. And the quantitative simulation model is to be applied in practice with more specific real data and Powersim Software modeling tool.

• Journal of the Society of Disaster Information
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• v.8 no.1
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• pp.71-80
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• 2012

It is necessary to establish guidelines when we selecting the civil defense evacuation facilities through quantitative analysis by civil defense evacuation facilities volume. The purpose of this study is to evaluate according to population density and distribution of the capacity of evacuation facilities. The results of this study are as follows. First, it is necessary to consider the capacity of evacuation facilities in order to set up the exact districts of civil defense evacuation facilities. Second, basic data based on to compare the condition of civil defense evacuation facilities is produced by an analysis on evacuation status of the target region. Third, it is proved to consider topographical conditions which do not move the shortest distance. Fourth, in order to create a realistic model, it is necessary to consider the model set various parameters.

• Applied Chemistry for Engineering
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• v.21 no.6
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• pp.689-693
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• 2010

When natural rubber dissolved in toluene comes into use as a binder of carbon powder, the volatilization of solvent just after the construction of biosensor brought the mechanical robustness on the paste. This characteristic satisfied the pre-requisite condition for the practical use of carbon paste electrode and a biosensor for the determination of hydrogen peroxide was designed. In order to evaluate its electrochemical qualitative and quantitative behaviors, various electrochemical kinetic parameters of the electrode, e.g. the symmetry factor (${\alpha}$, 0.37), the exchange current density ($i_0$, $0.075mAcm^{-2}$), the capacitance of double layer ($C_d$, $9.7{\times}10^{-3}F$), the time constant (${\tau}_A$, 0.92 s), the maximum current ($i_{max}$, $5.92{\times}10^{-7}Acm^{-2}$), the Michaelis constant ($K_M$, $1.99{\times}10^{-3}M$) and others were investigated. Results show that natural rubber is a promising binder of carbon powder.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.6
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• pp.517-523
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• 2013

Naphthyridine compounds are important, because they exhibit various biological activities including anticancer, antimicrobial, and anti-inflammatory activity. Some naphthyridines have antimitotic effects or demonstrate anticancer activity by inhibiting topoisomerase II. These compounds have been investigated as potential anticancer agents, and several compounds are now part of clinical trials. A series of naphthyridine derivatives were evaluated for their in vitro cytotoxic activities against human cervical cancer (HeLa), leukemia (HL-60), and prostate cancer (PC-3) cell lines using an MTT assay. Some compounds (14, 15, and 16) were more potent than colchicine against all three human cancer cell lines and compound (16) demonstrated potency with $IC_{50}$ values of 0.7, 0.1, and $5.1{\mu}M$, respectively. Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were used for quantitative structure-activity relationship (QSAR) molecular modeling of these compounds. We obtained accurate and predictive three-dimensional QSAR (3D-QSAR) models as indicated by the high PLS parameters of the HeLa ($q^2$, 0.857; $r^2$, 0.984; $r^2\;_{pred}$, 0.966), HL-60 ($q^2$, 0.777; $q^2$, 0.937; $r^2\;_{pred}$, 0.913), and PC-3 ($q^2$, 0.702; $q^2$, 0.983; $r^2\;_{pred}$, 0.974) cell lines. The 3D-QSAR contour maps suggested that the C-1 NH and C-4 carbonyl group of the naphthyridine ring and the C-2 naphthyl ring were important for cytotoxicity in all three human cancer cell lines.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.555-560
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• 2014

In Korea, quantitative growth rate of artificial reef construction is supposed to reach the peak point therefore, new approach is needed to the point of artificial reefs business. Functional reefs like shellfish reefs, recreational reefs, seaweed reefs as well as fish reefs are beneficial alternatives. This study conducted hydraulic testing to assess the stability of new types of artificial reefs (ARs) constructed to promote the growth of shellfish and seaweed. The results of this study revealed that some dimensionless design parameters affected the stability of new types of artificial reef under various wave and water depth conditions in the fixed bed condition. The findings also highlight the importance of hydraulic experiments in solving problems that have emerged in the design and construction of artificial reefs.

• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1604-1612
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• 2011

We developed three-dimensional quantitative structure activity relationship (3D-QASR) models for 17 adamantyl derivatives as P-glycoprotein (P-gp) inhibitors. Eighteen different partial charge calculation methods were tested to check the feasibility of the 3D-QSAR models. Best predictive comparative molecular field analysis (CoMFA) model was obtained with the Austin Model 1-Bond Charge Correction (AM1-BCC) atomic charge. The 3D-QSAR models were derived with CoMFA and comparative molecular similarity indices analysis (CoMSIA). The final CoMFA model ($q^2$ = 0.764, $r^2$ = 0.988) was calculated with an AM1-BCC charge and electrostatic parameter, whereas the CoMSIA model ($q^2$ = 0.655, $r^2$ = 0.964) was derived with an AM1-BCC charge and combined steric, electrostatic, hydrophobic and HB-acceptor parameters. Leave-five-out (LFO) cross-validation was also performed, which yielded good correlation coefficient for both CoMFA (0.801) and CoMSIA (0.656) models. Robustness of the developed models was checked further with 1000 run bootstrapping analyses, which gave an acceptable correlation coefficient for CoMFA (BS-$r^2$ = 0.997, BS-SD = 0.003) and CoMSIA (BS-$r^2$ = 0.996, BS-SD = 0.018).

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5897-5901
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• 2012

The aim of the study was to clarify the role of gastrokine 1 in the process of formation and development of gastric cancer. The expression of gastrokine 1 in gastric cancer and corresponding non-cancerous gastric tissues of 52 gastric cancer patients was assessed with the real-time fluorescence quantitative polymerase chain reaction (RT-PCR) and immunohistochemistry. We also analyzed the relationship between the expression level and clinicopathological characteristics. Gastrokine 1 gene and protein expression in gastric cancer tissues was in both cases significantly lower than in corresponding non-cancerous gastric tissues (both P<0.01), but no significant relationship was found with clinicopathological parameters including tumor location, depth of invasion, differentiation, lymph node metastasis, stage, gender, age and carcinoembryonic antigen (CEA), and carbohydrate antigen 19-9 (CA19-9) level in peripheral blood preoperation of patients (P>0.05, respectively). Furthermore, gastrokine 1 gene expression was markedly lower in gastric cancer tissues of Helicobacter pylori (HP)-positive patients than negative ones (P<0.05). The result of the study showed that gastrokine 1 might play a significant role in the process of formation and development of gastric cancer as an anti-oncogene. Its effect might be weakened by HP infection.