• Journal of Cardiovascular Imaging
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• v.30 no.4
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• pp.263-275
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• 2022

BACKGROUND: Cardiac allograft vasculopathy (CAV) is a complication beyond the first-year post-heart transplantation (HTx). We aimed to test the utility of cardiac magnetic resonance (CMR) to detect functional/structural changes in HTx recipients with CAV. METHODS: Seventy-seven prospectively recruited HTx recipients beyond the first-year post-HTx and 18 healthy controls underwent CMR, including cine imaging of ventricular function and T1- and T2-mapping to assess myocardial tissue changes. Data analysis included quantification of global cardiac function and regional T2, T1 and extracellular volume based on the 16-segment model. International Society for Heart and Lung Transplantation criteria was used to adjudicate CAV grade (0-3) based on coronary angiography. RESULTS: The majority of HTx recipients (73%) presented with CAV (1: n = 42, 2/3: n = 14, 0: n = 21). Global and segmental T2 (49.5 ± 3.4 ms vs 50.6 ± 3.4 ms, p < 0.001;16/16 segments) were significantly elevated in CAV-0 compared to controls. When comparing CAV-2/3 to CAV-1, global and segmental T2 were significantly increased (53.6 ± 3.2 ms vs. 50.6 ± 2.9 ms, p < 0.001; 16/16 segments) and left ventricular ejection fraction was significantly decreased (54 ± 9% vs. 59 ± 9%, p < 0.05). No global, structural, or functional differences were seen between CAV-0 and CAV-1. CONCLUSIONS: Transplanted hearts display functional and structural alteration compared to native hearts, even in those without evidence of macrovasculopathy (CAV-0). In addition, CMR tissue parameters were sensitive to changes in CAV-1 vs. 2/3 (mild vs. moderate/severe). Further studies are warranted to evaluate the diagnostic value of CMR for the detection and classification of CAV.

• Radiation Oncology Journal
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• v.16 no.2
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• pp.99-106
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• 1998

Purpose : We conducted clonogenic assay using human cancer cell lines (MKN-45, PC-14, Y-79, HeLa) to investigate a correlation between the parameters of radiosensitivity. Materials and Methods : Human cancer cell lines were irradiated with single doses of 1, 2, 3, 5, 7 and 10Gy for the study of radiosensitivity and subrethal damage repair capacity was assessed with two fractions of 5Gy separated with a time interval of 0, 1, 2, 3, 4, 6 and 24 hours. Surviving fraction was assessed with clonogenic assay using $Sperman-H\"{a}rbor$ method and mathematical analysis of survival curves was done with linear-quadratic (LQ) , multitarget-single hit(MS) model and mean inactivation dose$(\v{D})$. Results : Surviving fractions at 2Gy(SF2) were variable among the cell lines, ranged from 0.174 to 0.85 The SF2 of Y-79 was lowest and that of PC-14 was highest(p<0.05, t-test). LQ model analysis showed that the values of $\alpha$ for Y-79, MKN-45, HeLa and PC-14 were 0.603, 0.356, 0.275 and 0.102 respectively, and those of $\beta$ were 0.005, 0.016, 0.025 and 0.027 respectively. Fitting to MS model showed that the values of Do for Y-79. MKN-45, HeLa and PC-14 were 1.59. 1.84. 1.88 and 2.52 respectively, and those of n were 0.97, 1.46, 1.52 and 1 69 respectively. The $\v{D}s$ calculated by Gauss-Laguerre method were 1.62, 2.37, 2,01 and 3.95 respectively So the SF2 was significantly correlated with $\alpha$, Do and $\v{D}$. Their Pearson correlation coefficiencics were -0.953 and 0,993. 0.999 respectively(p<0.05). Sublethal damage repair was saturated around 4 hours and recovery ratios (RR) at plateau phase ranged from 2 to 3.79. But RR was not correlated with SF2, ${\alpha}$, ${\beta}$, Do, $\v{D}$. Conclusion : The intrinsic radiosensitivity was very different among the tested human cell lines. Y-79 was the most sensitive and PC-l4 was the least sensitive. SF2 was well correlated with ${\alpha}$, Do, and $\v{D}$. RR was high for MKN-45 and HeLa but had nothing to do with radiosensitivity parameters. These basic parameters can be used as baseline data for various in vitro radiobiological experiments.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.4
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• pp.386-408
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• 1988

A study was conducted to develop a model for estimating evapotranspiration and yield of Chinese cabbages from meteorological factors from 1981 to 1986 in Suweon, Korea. Lysimeters with water table maintained at 50cm depth were used to measure the potential evapotranspiration and the maximum evapotranspiration in situ. The actual evapotranspiration and the yield were measured in the field plots irrigated with different soil moisture regimes of -0.2, -0.5, and -1.0 bars, respectively. The soil water content throughout the profile was monitored by a neutron moisture depth gauge and the soil water potentials were measured using gypsum block and tensiometer. The fresh weight of Chinese cabbages at harvest was measured as yield. The data collected in situ were analyzed to obtain parameters related to modeling. The results were summarized as followings: 1. The 5-year mean of potential evapotranspiration (PET) gradually increased from 2.38 mm/day in early April to 3.98 mm/day in mid-June, and thereafter, decreased to 1.06 mm/day in mid-November. The estimated PET by Penman, Radiation or Blanney-Criddle methods were overestimated in comparison with the measured PET, while those by Pan-evaporation method were underestimated. The correlation between the estimated and the measured PET, however, showed high significance except for July and August by Blanney-Criddle method, which implied that the coefficients should be adjusted to the Korean conditions. 2. The meteorological factors which showed hgih correlation with the measured PET were temperature, vapour pressure deficit, sunshine hours, solar radiation and pan-evaporation. Several multiple regression equations using meteorological factors were formulated to estimate PET. The equation with pan-evaporation (Eo) was the simplest but highly accurate. PET = 0.712 + 0.705Eo 3. The crop coefficient of Chinese cabbages (Kc), the ratio of the maximum evapotranspiration (ETm) to PET, ranged from 0.5 to 0.7 at early growth stage and from 0.9 to 1.2 at mid and late growth stages. The regression equation with respect to the growth progress degree (G), ranging from 0.0 at transplanting day to 1.0 at the harvesting day, were: $$Kc=0.598+0.959G-0.501G^2$$ for spring cabbages $$Kc=0.402+1.887G-1.432G^2$$ for autumn cabbages 4. The soil factor (Kf), the ratio of the actual evapotranspiration to the maximum evapotranspiration, showed 1.0 when the available soil water fraction (f) was higher than a threshold value (fp) and decreased linearly with decreasing f below fp. The relationships were: Kf=1.0 for $$f{\geq}fp$$ Kf=a+bf for f$$I{\leq}Esm$$ Es = Esm for I > Esm 6. The model for estimating actual evapotranspiration (ETa) was based on the water balance neglecting capillary rise as: ETa=PET. Kc. Kf+Es 7. The model for estimating relative yield (Y/Ym) was selected among the regression equations with the measured ETa as: Y/Ym=a+bln(ETa) The coefficients and b were 0.07 and 0.73 for spring Chinese cabbages and 0.37 and 0.66 for autumn Chinese cabbages, respectively. 8. The estimated ETa and Y/Ym were compared with the measured values to verify the model established above. The estimated ETa showed disparities within 0.29mm/day for spring Chinese cabbages and 0.19mm/day for autumn Chinese cabbages. The average deviation of the estimated relative yield were 0.14 and 0.09, respectively. 9. The deviations between the estimated values by the model and the actual values obtained from three cropping field experiments after the completion of the model calibration were within reasonable confidence range. Therefore, this model was validated to be used in practical purpose.

• Tuberculosis and Respiratory Diseases
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• v.49 no.1
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• pp.37-48
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• 2000

Backgrounds : The pathophysiology of chronic airflow obstruction, such as bronchial asthma, is characterized by mucus hypersecretion, goblet cell hyperplasia(GCH), smooth muscle hypertrophy, and inflammatory cells infiltration. In fatal asthma patients, one distinct findings is mucus hypersecretion due to GCH. However, the mechanisms of GCH in these hypersecretory diseases remain still unknown. In this study, a rat model was rapidly induced with GCH by instillation of $TiO_2$, intratracheally. We intend to confirm GCH and association of concomitant inflammatory cells infiltration and to observe the effect of potent antiinflammatory agent, that is dexamethasone, on GCH with inflammatory cells. Methods : Twenty-one 8-weeks-old male Sprague-Dawley rats were divided into three groups. Endotoxinfree water was instilled intratracheally in group 1(control) ; $TiO_2$, was instilled in the group 2 ; and dexamethasone was injected intraperitoneally to group 3 before $TiO_2$ instillation. After 120 hours, all rats were sacrificed, and trachea, bronchi, and lungs were resected respectively. These tissues were made as paraffin blocks and stained as PAS for goblet cells and Luna stain for eosinophils. We calculated the ratio of goblet cell to respiratory epithelium and number of infiltrated eosinophils from each tissue. Results : (1) Fraction of goblet cells was significantly increased in group 2 than in group 1 in the trachea and in the main bronchus. (10.19$\pm$11.33% vs 4.09$\pm$8.28%, p<0.01 and 34.09$\pm$23.91% vs 3.61$\pm$4.84%, p<0.01, respectively). (2) Eosinophils were significantly increased in the airway of group 2 than that of group 1. (5.43$\pm$3.84% vs 0.17$\pm$0.47 in trachea and 47.71$\pm$16.91 vs 2.71$\pm$1.96 in main bronchi). (3) There was a positive correlation between goblet cells and eosinophils(r=0.719, p=0.001). (4) There was significant difference in the decrease of goblet cells after dexamethasone injection between group 2 and group 3 (p<0.01). Also, infiltration of eosinophils was suppressed by dexamethasone. Conclusion : We made an animal model of $TiO_2$-induced goblet cell hyperplasia. GCH was observed mainly in the main bronchi with concomitant eosinophilic infiltration. Both goblet cell hyperplasia and eosinophilic infiltration were suppressed by dexamethasone. This animal model may serve as a useful tool in understanding of the mechanism of GCH in chronic airway diseases.

• Progress in Medical Physics
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• v.11 no.2
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• pp.157-165
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• 2000

Purpose: For estimation of yields of l)NA damages induced by radiation and enhanced by oxygen, a mathematical model was used and tested. Materials and Methods: Reactions of the products of water radiolysis were modeled as an ordinary time dependant equations. These reactions include formation of radicals, DNA damage, damage repair, restitution, and damage fixation by oxygen and H-radical. Several rate constants were obtained from literature while others were calculated by fitting an experimental data. Sensitivity studies were performed changing the chemical rate constant at a constant oxygen number density and varying the oxygen concentration. The effects of oxygen concentration as well as the damage fixation mechanism by oxygen were investigated. Oxygen enhancement ratio(OER) was calculated to compare the simulated data with experimental data. Results: Sensitivity studies with oxygen showed that DNA survival was a function of both oxygen concentration and the magnitude of chemical rate constants. There were no change in survival fraction as a function of dose while the oxygen concentration change from 0 to 1.0 x 10$^{7}$ . When the oxygen concentration change from 1.0 $\times$ 107 to 1.0 $\times$ 101o, there was significant decrease in cell survival. The OER values obtained from the simulation study were 2.32 at 10% cell survival level and 1.9 at 45% cell survival level. Conclusion: Sensitivity studies with oxygen demonstrated that the experimental data were reproduced with the effects being enhanced for the cases where the oxygen rate constants are largest and the oxygen concentration is increased. OER values obtained from the simulation study showed good agreement for a low level of cell survival. This indicated that the use of the semi-empirical model could predict the effect of oxygen in cell killing.

• Korean Journal of Materials Research
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• v.8 no.7
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• pp.621-627
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• 1998

The formation of Co-silicide between Co/Zr bilayer on the amorphous and crystalline Si substrates has been investigated. The films of Zr(50$\AA$) and Co(l50$\AA$) were deposited with e-beam evaporation system and were heattreated with the rapid thermal annealing system at the temperatures between 50$0^{\circ}C$ and 80$0^{\circ}C$ with 10$0^{\circ}C$ increments for 30 seconds. The phase identification of Co-silicide was carried out by XRD and the chemical analysis was examined by AES and RBS. The interface morphologies of Co/Zr bilayer films were investigated by cross sectional TEM and HRTEM. $CoSi_2$ was formed epitaxially on the crystalline Si substrate above $700^{\circ}C$ while polycrystalline $CoSi_2$ was grown on the amorphous Si substrate. The formation temperature of Co-silicide on the amorphous Si substrate was about 100 C lower than that on the crystalline Si. The COzSi phase was not identified on the both Si substrates. The formation temperature of first phase of Co-silicide on ColZr bilayer was higher than that on Co mono layer. CoSizlayer formed on the amorphous Si substrate exhibits better uniformity compared to the CoSiz formed on the crystalline substrate. The sheet resistance of CoSiz layer on crystalline Si was lower than that on the amorphous Si at high temperatures.tures.

• Korean Journal of Pharmacognosy
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• v.40 no.3
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• pp.196-204
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• 2009

This study was carried out to investigate the in vivo and in vitro inhibitory effect of a traditional herbal complex (HC) extract prepared from a mixture of four oriental herbs (Dioscorea Rhizoma, Glycine soja Sieb. et Zucc, Bombycis corpus, Fermented Glycine soja) that have been widely used for the treatment and prevention of diabetes mellitus on hyperglycemia. The water extract of HC showed potent inhibitory effect on $\alpha$-glucosidase with $IC_{50}$ value of 1.24 mg/mL. Additionally, the ethanol extract of HC was also found to exhibit significant inhibitory effect against protein tyrosine phosphatase $1{\beta}$ ($PTP1{\beta}$), which is known as a major regulator of both insulin and leptin signaling. In the $PTP1{\beta}$ inhibitory assay, the most active n-hexane fraction obtained from the ethanol extract of HC, was identified as a mixture of fatty acid derivatives by gas chromatography-mass spectrometry (GC-MS). In high-fat diet-low dose streptozotocin (STZ)-induced diabetic rat, the water extract of HC improved the oral glucose intolerance as compared with rosiglitazone. HC also caused a marked decrease of body weight and fasting blood glucose and a significant improvement on glucose tolerance in metabolic syndrome mice model. These findings support that this traditional HC may be useful in the control of blood glucose in diabetes mellitus and metabolic syndrome.

• Journal of Korea Water Resources Association
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• v.40 no.11
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• pp.887-898
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• 2007

A physically based semi-distributed model, SWAT was applied to the Chungju Dam upstream watershed in order to investigate the spatial and temporal characteristics of watershed sediment yields. For this, general features of the SWAT and sediment simulation algorithm within the model were described briefly, and watershed sediment modeling system was constructed after calibration and validation of parameters related to the runoff and sediment. With this modeling system, temporal and spatial variation of soil loss and sediment yields according to watershed scales, land uses, and reaches was analyzed. Sediment yield rates with drainage areas resulted in $0.5{\sim}0.6ton/ha/yr$ excluding some upstream sub-watersheds and showed around 0.51 ton/ha/yr above the areas of $1,000km^2$. Annual average soil loss according to land use represented the higher values in upland areas, but relatively lower in paddy and forest areas which were similar to the previous results from other researchers. Among the upstream reaches, Pyeongchanggang and Jucheongang showed higher sediment yields which was thought to be caused by larger area and higher fraction of upland than other upstream sub-areas. Monthly sediment yields at the main outlet showed same trend with seasonal rainfall distribution, that is, approximately 62% of annual yield was generated during July to August and the amount was about 208 ton/yr. From the results, we could obtain the uniform value of sediment yield rate and could roughly evaluate the effect of soil loss with land uses, and also could analyze the temporal and spatial characteristics of sediment yields from each reach and monthly variation for the Chungju Dam upstream watershed.

• Korean Journal of Food Science and Technology
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• v.14 no.4
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• pp.375-381
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• 1982

The studies are conducted on the changes of soybean lipids in terms of physicochemical characteristics, lipid classess and fatty acid composition during the fermentation process of soybean Koji preparation for daenjang (soybean paste) in a model system using cooked soybean inoculated by Aspergillus oryzae. The total lipids contents were increased during soybean Koji preparation, generally iodine values decreased but acid values increased. Total lipids of soybean Koji consisted of about 90.6% neutral lipids, 7.6% phospholipids and 1.8%, glycolipids indicating that phospholipids contents of soybean Koji was increased when compared to those of cooked soybean. The major components of nonpolar lipids in soybean Koji were free fatty acids(39.6%) and triglycerids(29.2%). Free fatty acids increased as the triglycerides decreased during soybean Koji preparation by the hydrolysis of lipase action. The major components of polar lipids in soybean Koji were phosphatidyl choline and phosphatidyl ethanolamine. Differences were observed in the composition of the polar lipids of cooked soybean and soybean Koji. A little changes also occurred in fatty acid compositions of total lipids, triglycerides and free fatty acids fractions in soybean Koji preparation. Especially a considerable increase of linoleic acid in free fatty acid fraction was observed in soybean Koji.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.181-186
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• 2003

The satellite navigation system is widely used for identifying a user's position regardless of weather or geographic conditions and also make effect on new technology of marine LBS(Location Based Service), which has the technology of geographic information such as the ENC. Generally, there are conceivable systems of marine LBS such as ECDIS, or ECS that use the ENC itself with powerful processor in installed type on ships bridge. Since the ENC is relatively heavy structure with dummy format for data transfer between different systems, we should reduce the ENC to small and compact size in order to use it in mobile platform. In this paper, we assumed that the mobile system like PDA, or Webpad can be used for small capability of mobile platform. However, the ENC should be updated periodically by update profile data produced by HO. If we would reduce the ENC without a consideration of update, we could not get newly updated data furthermore. As summary, we studied considerations for ENC reduction with update capability. It will make the ENC be useful in many mobile platforms for various applications.