• Journal of radiological science and technology
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• v.47 no.3
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• pp.213-218
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• 2024

The myocardial nuclear medicine examination is widely performed to diagnose myocardium disease using various radionuclides. Although image quality according to radionuclides has improved, the radiation exposure for target organ as well as peripheral organs should be considered. Here, the aim of this study was to evaluate absorbed dose (Gy) for peripheral organs in myocardial nuclear medicine scan from myocardium according to various scan environments based on Monte Carlo simulation. The simulation environment was modeled 5 cases, which were considered by radionuclides, number of injections, and radiodosage. In addition, the each radionuclide simulation such as distribution fraction was considered by recommended standard protocol, and the mesh computational female phantom, which is provided by International Commission on Radiological Protection (ICRP) 145, was used using the particle and heavy ion transport code system (PHITS) version 3.33. Based on the results, the closer to the myocardium, the higher the absorbed dose values. In addition, application for dual injection for radionuclides leaded to high absorbed dose compared with single injection for radionuclide. Consequently, there is difference for absorbed dose according to radionuclides, number of injections, and radiodosage. To detect the accurate diseased area, acquisition for improved image quality is crucial process by injecting radionuclides, however, we need to consider absorbed dose both target and peripheral inner organs from radionuclides in terms radiation protection for patient.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.309-316
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• 2009

Purpose: F-18 FDG can be accumulated in the liver, bowel, kidney, urinary tract, and muscles physiologically. The aim of this study was to evaluate the clinical value of dual time point 18F-FDG PET /8 imaging for the differentiation of the colonic focal uptake lesions. Materials and Methods: One hundred thirty two patients (M:F = 77:55, Age 62.8$\pm$11.6 years) underwent $^{18}$F-FDG PET/CT at two time points, prospectively: early image at 50-60 min and delayed image at 4-4.5 hours after the intravenous injection of $^{18}$F-FDG. Focally increased uptake lesions on early images but disappeared or shifted on delayed images defined a physiological uptake. For the differential evaluation of persistent focal uptake lesions on delayed images, colonoscopy and histopathologic examination were performed. SUVmax changes between early and delayed images were also compared. Results: Among the 132 patients, 153 lesions of focal colonic uptake were detected on early images of $^{18}$F-FDG PET/CT. Of these, 72 (47.1%) lesions were able to judge with physiological uptake because the focal increased uptake disappeared from delayed image. Among 81 lesions which was showed persistent increased uptake in delayed image, 61 (75.3%) lesions were confirmed as the malignant tumor and 14 (17.3%) lesions were confirmed as the benign lesions including adenoma and inflammatory disease. Remaining 6 (7.4%) lesions were confirmed as the physiological uptake because there was no particular lesion in the colonoscopy. In the malignant lesions, the calculated dual time point change for SUVmax ($\Delta$%SUVmax) was 20.8$\pm$18.7%, indicating a significant increase in SUVmax between the two point (p<0.01). In contrast, the change in SUVmax for the non-malignant lesions including benign lesions and physiological uptake was -13.7%$\pm$24.2%. For the differentiation of the malignant and non-malignant focal colonic uptake lesions, $\Delta$%SUVmax was the most effective parameter, and the cut-off value using -5% provided the best sensitivity, specificity, and accuracy. Conclusion: The dual time point $^{18}$F-FDG PET/CT imaging with SUVmax change evaluation could be an important noninvasive method for the differentiation of malignant and benign focal colonic uptake lesions including physiologic uptake.

• Journal of the Korean Institute of Gas
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• v.20 no.6
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• pp.43-49
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• 2016

In this paper, purpose of study is emissions characteristics according to effects of heating value variations of CNG fuel in a dual-fuel engine fueled by diesel and natural gas. For heating value variation of CNG fuel, nitrogen gas was mixed with pure CNG fuel. So the higher heating value was changed from $10,400kcal/Nm^3$ to $9,400kcal/Nm^3$. Under one condition of CNG substitution rate was fixed at 80%, diesel fuel was injected at a fixed injection timing of 16 CAD BTDC and fuel pressure was also fixed at 110 MPa. The condition of tested engine was 1800 rpm and 500Nm. Emissions were sampled in exhaust pipe was located at downstream turbocharger. As a result, emissions characteristics were checked in heating value variations of CNG fuel with mixed nitrogen gas THC, $CH_4$ and CO emissions decreased and NOx and $CO_2$ increased.

• Journal of the Korean institute of surface engineering
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• v.49 no.3
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• pp.316-321
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• 2016

To study emission characteristics for dual-emission tandem organic light emitting display (OLED), we fabricated blue fluorescent OLED according to thickness variation of $MoO_x$ as charge generation layer and Al as cathode. The bottom emission characteristics of OLED with $MoO_x$ 2, 3, 5 nm thickness showed threshold voltage of 9, 7, 9 V, maximum current emission efficiency of 19.32, 23.18, 15.44 cd/A and luminance of $1,000cd/m^2$ at applied voltage of 17.6, 13.2, 16.5 V, respectively. The top emission characteristics of OLED with $MoO_x$ 2, 3, 5 nm thickness indicated threshold voltage of 13, 10, 13 V, maximum current emission efficiency of 0.17, 0.23, 0.16 cd/A and luminance of $50cd/m^2$ at applied voltage of 22.6, 16.5, 20.1 V, respectively. In case of thicker or thinner than $MoO_x$ of 3 nm, the emission characteristics were decreased because of mismatching of electron and hole in emission layer. The bottom emission characteristics of OLED with Al 15, 20, 25 nm thickness showed threshold voltage of 8, 8, 7 V, maximum current emission efficiency of 18.42, 22.98, 23.18 cd/A and luminance of $1000cd/m^2$ at applied voltage of 16.2, 13.9, 13.2 V, respectively. The reduction of threshold voltage and increase of maximum current emission efficiency are caused by the increase of current injection according to increase of Al cathode thickness. The top emission characteristics of OLED with Al 15, 20, 25 nm thickness indicated threshold voltage of 7, 7, 8 V, maximum emission luminance of 371, 211, $170cd/m^2$, respectively. The top emission OLED of Al cathode with 15 nm thickness showed maximum luminance and it decreased at thickness of 20 nm. These phenomena are caused by the decrease of intensity of emitted light by reduction of optical transmittance according to increase of Al cathode thickness.

• Archives of Plastic Surgery
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• v.34 no.2
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• pp.163-168
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• 2007

Purpose: The flap delay is a widely used technique to increase the flap survival. Dexamethasone is a well-known drug to have a positive impact on the flap survival. The objective of this study is to investigate the dual synergic effect of epinephrine as a chemical delay agent plus dexamethasone on the TRAM flap survival in rat model. Methods: Forty Sparague-Dawley rats were divided into 4 groups evenly and a right inferior epigastic vessel pedicled TRAM flap, sized $5.0{\times}3.0cm$, was elevated on each upper abdomen. In the control group(N=10), 2 ml saline was injected on transverse abdominis muscle for a week before the flap elevation. In surgical delay group(N=10) all superior pedicles and left inferior pedicle were ligated a week before the flap elevation. In epinephrine group (N=10), 1 : 50000 epinephrine mixed saline was injected to transverse abdominis muscle every day for a week before flap elevation. In epinephrine plus dexamethasone group (N=10), the same procedure as that of epinephrine group was conducted for a week and 2.5 ml/kg dexamethasone was injected transverse abdominis muscle 2 hours before the flap elevation. On the seventh day after flap elevation, the survival area of flaps were measured and the vessel numbers in upper dermis of flap were counted through histologic slides. Results: The results were as follows: the mean percentage of the flap survival area of surgical delay group ($60.5{\pm}2.44%$), epinephrine group ($75{\pm}4.43%$), and epinephrine plus dexamethasone group ($87{\pm}1.94%$) were higher than that of the control group ($35{\pm}6.06%$) significantly(p<0.05). In case of the vessel number though histologic slides, epinephrine group ($79.3{\pm}5.57$) and epinephrine plus dexamethasone group ($96.3{\pm}14.05$) were higher than that of the control group ($44.8{\pm}8.82$) significantly(p<0.05), but the surgical delay group ($54{\pm}4.23$) showed no significant difference (p>0.05) compared to that of the control group. Conclusion: The results indicated that epinephrine plus dexamethasone injection before the flap elevation could be used to increase the TRAM flap survival area in rat model.

• Food Science and Biotechnology
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• v.14 no.4
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• pp.456-460
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• 2005

To enforce the maximum residue limit for residual hexane (0.005 g/kg) in commercially available Korean vegetable oil, convenient and accurate quantification methods were investigated. Using dual surrogate standards, pentane and heptane were dissolved in ethanol, and then added to hexane-tree sunflower oil for setting up the calibration curve. Gas Chromatograph-Flame Ionization Detector with a porous layer open tubular column, indicated good chromatographic separation of hexane from other inhibiting matrix components. The lowest calibration level was $0.5\;{\mu}g/g$, not exceeding a relative standard deviation of 10% (RSD%), and 1.0\;{\mu}g/g$ not exceeding a deviation of 22% RSD% using heptane as an internal standard for the Static headspace analysis by using a headspace auto-sampler and manual injection, respectively. The residual hexane was detected in nine of the samples among 87 vegetable oil samples purchased on the local market.

• Journal of Pharmaceutical Investigation
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• v.9 no.3
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• pp.27-38
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• 1979

This study was attempted to investigate the pharmacological action, especially depressor action of Phellodendri cortex and to elucidate the mechanism of its action, making use of Phellodendri cortex methanol extract (PCME) because its hypotensive action is not clear. Influence of PCME on the blood pressure of the rabbits and cats were observed in this study. PCME, when given intravenously in the rabbits and cats, elicited the hypotensive action, but intraventricular PCME in the rabbits did not show depressor action. Accumulation and tachyphylaxis by PCME administered into the ear-vein of the rabbits were not shown. Depressor effect of PCME in the rabbits was attenuated significantly by pretreatment with phentolamine, guanethidine, chorisondamine and atropine, but not by propranolol, diphenhydramine, cyproheptadine and vagotomization. The pressor activity of angiotensin was unimpaired after injection of maximal hypotensive doses (100mg/kg) of PCME, but the pressor activity of norepinephrine and carotid occlusion was abolished markedly. In addition, PCME given into jugular vein of the cats weakened norepinephrine pressor responses and caused the reversal of epinephrine pressor responses. These results suggest that the hypotensive action of PCME may be due to dual mechanisms by interference with peripheral sympathetic function, alpha adrenoceptor blocking action, and peripheral parasympathomimetics action, muscarinic action.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.4
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• pp.239-250
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• 2020

In this study, effects of five raw water quality parameters (turbidity, odor compounds caused by algae, filter clogging caused by algae, pH increase caused by algae, and organic matter) on improvements and operations costs of typical water treatment plant (WTP) were estimated. The raw water quality parameters were assumed the worst possible conditions based on the past data and costs were subsequently estimated. Results showed that new water treatment facilities were needed, such as a selective intake system, an advanced water treatment processes, a dual media filter, a carbonation facility, and a re-chlorination facility depending on water quality. Furthermore, changes needed to be made in WTP operations, such as adding powered activated carbon, increasing the injection of chlorine, adding coagulation aid, increasing the discharge of backwashed water, and increasing the operation time of dewatering facilities. Such findings showed that to reliably produce high-quality tap water and reduce water treatment costs, continuous improvements to the quality of water sources are needed.

• Journal of the Korean Society of Combustion
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• v.3 no.2
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• pp.13-27
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• 1998

The optimization of frontal device including fuel nozzle and swirler is required to secure the mixing of fuel and air and the combustion stability leading the reduction of pollutant emissions and the increase of combustion efficiency in gas turbine combustor. The effects of injection nozzle and swirler on the flow field, spray characteristics and consequently the combustion stability, were experimentally investigated by measuring the velocity field, droplet sizes of fuel spray, lean combustion limit and the temperature field in the main combustion region. Flow fields and spray characteristics were measured with APV(Adaptive Phase Doppler Velocimetry) under atmospheric condition using kerosine fuel. Temperatures were measured by Pt-Pt13%Rh, R-type thermocouple which was 0.2mm thick. Spray and flame was visualized by ICCD(Intensified Charge Coupled Device) camera. It was found that the dual swirler resulted in the biggest recirculation zone with the highest reverse flow velocity at the central region, which lead the most stable combustion. The various combustion characteristics were observed as a function of the geometries of injector and swirler, that gave a tip for the better design of gas turbine combustor.

• Journal of ILASS-Korea
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• v.14 no.4
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• pp.153-162
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• 2009

The use of inedible vegetable oils as substitute for diesel fuel in compression ignition engine is of significance because of the great need for edible oil as food, and the reduction of biodiesel production cost etc. Jatropha curcas oil which is a leading candidate for the commercialization of inedible vegetable oils is selected in this study for reviewing the application in CI engine as an alternative fuel. The important properties of jatropha oil (JO) and JO biodiesel are summarized from the various sources in the literature. It is found that five different types of alternative fuel from JO such as neat JO, JO blends with diesel or other fuel, neat JO biodiesel, JO biodiesel blends with diesel or other fuel and degummed JO were extensively examined in the diesel engine. Two different application types of alternative fuels from JO such as preheating and dual fuelling were also tested, It should be pointed out that most of these applications are limited to single cylinder conditions. The systematic study for the selection of effective application method is required. It is clear that the blends of JOME and diesel can replace diesel fuel up to 10% by volume for running the existing common rail direct injection systems without any durability problems. The systematic assessment of spray characteristics of different types of JO and its derivatives for use as diesel engine fuel is also required.