• Journal of Pharmaceutical Investigation
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• v.22 no.3
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• pp.185-196
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• 1992

To assess its suitability as a prodrug of 5-fluorouracil (5-FU), 1-glycyloxymethyl-5-FU HCl (GFU), a 5-fluorouracil derivative having a glycyloxymethyl group at the N-l position was synthetized. Its physicochemical properties and hydrolysis kinetics, in aqueous solution of pH $1{\sim}10$ and in the presence of human plasma or rat liver homogenate were studied. Its acute toxicity and antitumor activity against sarcoma 180 were also examined, GFU showed higher lipid/water partition coefficient than 5-FU. The calculated $pK_{\alpha}$ values of 5-FU and GFU were 8.02 and 7,20, respectively. The decomposition rates of GFU in aqueous solution showed a pH-dependence over the pH range used, which could be ascribed to solvent catalysed hydrolysis reaction at pH lower than 4,16 and to specific hydroxide ion hydrolysis reaction at pH higher than 4,16, The half-life of GFU was 6,9 min in 80% human plasma solution and less than 3 min in rat liver homogenate at $37^{\circ}C$, The $LD_{50}$ value of 5-FU was 240 mg/kg while that of GFU was 440.6 mg/kg (226 mg as 5-FU). Both of 5FU and GFU showed a strong antitumor activity, Therapeutic ratios of 5-FU and GFU were 3.07 and 3.55, respectively.

• KSBB Journal
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• v.9 no.3
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• pp.279-286
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• 1994

A mathematical model has been derived and used to describe phosphoprotein partitioning in Fe(III) IDA-PEG/dextran two-phase systems. This model includes the inhibitory effects of hydrogen and hydroxyl ion concentrations on protein partitioning. For aqueous two-phase partitioning experiments, the Al and A2 subcomponents of ovalbumin carrying two and one surface phosphoryl group(s) were purified using an immobilized metal ion affinity chromatography (IMAC). The ratio of partition coefficients in the presence and absence of Fe(III)IDA-PEG, K/Ko, increased in the pH range of 3.0 to 5.0 due to deprotonation of the second oxygen of the phosphoryl group, and above pH 5.0 declined steeply by the inhibitory binding of hydroxyl ions to the metal ion. This partitioning behavior was well described by the mathematical model. The binding constants for formation of the complex between the phosphoryl group and the Fe(III)IDA-PEG were found to be $6.1{\times}10^3M^{-1} and 2.3{\times}10^4M^{-1}$ in the top and bottom phases, respectively. These values are 3-5 times those for interaction of Cu(II)IDA-PEG with a single surface-accessible histidine.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2
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• pp.365-372
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• 2000

he paper introduces evolutionary computing to Fractal Image Compression(FIC). In Fractal Image Compression(FIC) a partitioning of the image into ranges is required. As a solution to this problem there is a propose that evolution computation should be applied in image partitionings. Here ranges are connected sets of small square image blocks. Populations consist of $N_p$ configurations, each of which is a partitioning with a fractal code. In the evolution each configuration produces $\sigma$ children who inherit their parent partitionings except for two random neighboring ranges which are merged. From the offspring the best ones are selected for the next generation population based on a fitness criterion Collage Theorem. As the optimum image includes duplication in image data, it gets smaller in saving space more efficient in speed and more capable in image quality than any other technique in which other coding is used. Fractal Image Compression(FIC) using evolution computation in multimedia image processing applies to such fields as recovery of image and animation which needs a high-quality image and a high image-compression ratio.

• Journal of radiological science and technology
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• v.46 no.2
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• pp.131-139
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• 2023

High-dose I-131 used for the treatment of thyroid cancer causes localized exposure among radiology technologists handling it. There is a delay between the calibration date and when the dose of I-131 is administered to a patient. Therefore, it is necessary to directly measure the radioactivity of the administered dose using a dose calibrator. In this study, we attempted to apply machine learning modeling to measured external dose rates from shielded I-131 in order to predict their radioactivity. External dose rates were measured at 1 m, 0.3 m, and 0.1 m distances from a shielded container with the I-131, with a total of 868 sets of measurements taken. For the modeling process, we utilized the hold-out method to partition the data with a 7:3 ratio (609 for the training set:259 for the test set). For the machine learning algorithms, we chose linear regression, decision tree, random forest and XGBoost. To evaluate the models, we calculated root mean square error (RMSE), mean square error (MSE), and mean absolute error (MAE) to evaluate accuracy and R² to evaluate explanatory power. Evaluation results are as follows. Linear regression (RMSE 268.15, MSE 71901.87, MAE 231.68, R² 0.92), decision tree (RMSE 108.89, MSE 11856.92, MAE 19.24, R² 0.99), random forest (RMSE 8.89, MSE 79.10, MAE 6.55, R² 0.99), XGBoost (RMSE 10.21, MSE 104.22, MAE 7.68, R² 0.99). The random forest model achieved the highest predictive ability. Improving the model's performance in the future is expected to contribute to lowering exposure among radiology technologists.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4B
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• pp.375-381
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• 2008

In this research, a physics based grid-multi layer distributed flood runoff model was developed to analyze discharge for the Namgang Dam Watershed ($2,293km^2$) and applied for sensitivity analysis for estimation of parameters, mainly initial soil moisture condition and saturate infiltration coefficient, which have a strong influence on discharge. Capability of the model was evaluated using VER and QER from the results of rainfall-runoff analysis and showed enhanced results of 6% compared to parameters before calibration. As the result with the sensitivity analysis of parameters, the part of the most influence on the runoff was the infiltration coefficient and ratio of layer partition. The total discharge and peak time showed comparatively precise runoff results without the initial calibration of the parameters.

• Journal of Pharmaceutical Investigation
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• v.23 no.3
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• pp.165-177
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• 1993

The relationship between the plasma haloperidol (HP) concentration and clinical response, and the effects of its active metabolite, reduced haloperidol (RH) on clinical response of HP were investigated in schizophrenic patients. In clinical study I, with 17 schizophrenic patients (male 8, fermale 9) who were administered with three different fixed doses of HP (15, 30 and 50 mg/day) for 3 weeks, the concentrations of HP and RH in plasma and blood and clinical response had been checked before and every week during the study. The clinical response was evaluated by the method of brief psychiatric rating scale (BPRS), and relative improvement of clinical response based on baseline BPRS (before drug treatment) was calculated. The concentrations of HP and RH in plasma and blood were assayed by HPLC. In clinical study II, the plasma RH/HP concentration ratios were checked in 11 patients who were administered with high doses of HP, over 60 mg a day, because of the poor clinical response at usual doses of HP. Plasma HP concentration and relative improvement of BPRS at 3 week in schizophrenic patients showed a 'curvilinear' relationship, and the clinical response was improved relatively over 50% based on the baseline BPRS in the range of $5{\sim}57\;ng/ml $ of HP in plasma. Also, the plasma RH concentrations were increased nonlinearly as the plasma HP concentration increased, and in high plasma HP concentration, over 30 ng/mI, clinical response gradually decreased, while the plasma RH/HP concentration ratio increased nonlinearly. Blood partition coefficients of HP and RH were not changed according to daily HP dose and duration of drug therapy. From these results, it is noted that the higher plasma RH/HP concentration ratio, resulted from the accumulation of RH as HP concentration increased, might explain the 'curvilinear' decrease of HP clinical response.

• Korean Journal of Remote Sensing
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• v.33 no.2
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• pp.111-123
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• 2017

The phycocyanin pigment (PC) is a marker for cyanobacterial presence in eutrophic inland water. Accurate estimation of low PC concentration in turbid inland water is challenging due to the optical complexity and criticalforissuing an early warning of potentialrisks of cyanobacterial bloom to the public. To monitor cyanobacterial bloom in eutrophic inland waters, an approach is proposed to partition non-water absorption coefficient from measured reflectance and to retrieve absorption coefficient of PC with the aim of improving the accuracy in remotely estimated PC, in particular for low concentrations. The proposed inversion model retrieves absorption spectra of PC ($a_{pc}({\lambda})$) with $R^2{\geq}0.8$ for $a_{pc}(620)$. The algorithm achieved more accurate Chl-a and PC estimation with $0.71{\leq}R^2{\leq}0.85$, relative root mean square error (rRMSE) ${\leq}39.4%$ and mean relative error(RE) ${\leq}78.0%$ than the widely used semi-empirical algorithm for the same dataset. In particular, low PC ($PC{\leq}50mg/m^3$) and low PC: Chl-a ratio values of for all datasets used in this study were well predicted by the proposed algorithm.

• Journal of Pharmaceutical Investigation
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• v.26 no.1
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• pp.1-11
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• 1996

Biphenyldimethyldicarboxylate (PMC), which has been used to treat hepatitis, is insoluble in water, therefore it has low bioavailability after oral administration. For the purpose of increasing the dissolution rate of PMC, the physical mixtures and inclusion complexes of PMC and $dimethyl-{\beta}-cyclodextrin\;(DM\;{\beta}CD)\;or\;hydroxypropyl-{\beta}-cyclodextrin\;(HP{\beta}CD)$ in molar ratio of 1 : 1 and 1 : 2 were prepared by solvent evaporation method. Mixed micelles of PMC were prepared by reacting PMC with bile salts [sodium cholate(NaC), sodium glycocholate (NaGC)] and oleic acid (OA) or palmitoylcarnitine chloride(PCC). Chloroform/water partition coefficient (PC) of PMC was 36.14 in artificial gastric juice (AGJ) and 33.47 in artificial intestinal juice (AIJ), respectively, on the other hand octanol/water PC was 63.36. PMC formulation was prepared by reacting PMC with PEG400-glycerin system(95 : 5, 90 : 10, respectively) and PEG400-PEG4000-glycerin system (70 : 25 : 5, 65 : 25 : 10, respectively). Dissolution test was performed in AGJ and AIJ by paddle method at $37{\pm}0.5^{\circ}C$. The dissolution rates of PMC tablets on the market were 5.74% and 8.26% at AGJ and AIJ, respectively and marketed PMC capsules were 22.14% and 28.64% at AGJ and AIJ, respectively. The dissolution rates of inclusion complexes of PMC with $DM{\beta}CD$ and $HP{\beta}CD$ in a molar ratio of 1 : 1 were more fast than those of corresponding physical mixtures. The decreasing order of dissolution rates was as follows; PMC-PEG400-PEG4000-glycerin formulation > PMC-PEG400-glycerin formulation > mixed micelles > CD inclusion complexes. The dissolution rates of PMC-PEG400-glycerin and PMC-PEG400-PEG4000-glycerin formulation were most fast and the percentage of dissolution was almost 100% within 20 minutes. And their dissolution rates after 120 minutes were markedly increased as compared with capsules on the market (4.0-fold and 3.2-fold in PMC-PEG400-glycerin formulation at AGJ and AIJ, respectively, and 4.8-fold and 3.7-fold in PMC-PEG400-PEG4000-glycerin formulation at AGJ and AIJ, respectively).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.3
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• pp.273-281
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• 1990

Two rice varieties, Samkangbyeo and Sangpungbyeo, were transplanted on 1/2000a pots at 6 different dates beginning on May 11 with 10 day interval in 1987 and at 4 different dates beginning on May 21 with 10 day interval in a paddy field at the Chungbuk Provincial Rural Development Administration. Dry matter distributions to stem and leaf sheath, leaves and ear at different growth stages were analyzed to provide basic informations neccessary for the development of dynamic growth model. Dry matter production was reduced as transplanting was delayed and the degree of reduction was greater at the transplanting later than June 1. Dry matter distribution to stem and leaf sheath was increased up to 60-70 days after transplanting with the maximum ratio between 60-70%, which were decreased to 37-43% in pots and 27-33% in field at the end of ripening stage. On the other hand, dry matter distribution to leaf blade was decreased from 40-50% at transplanting to 11-17% at harvesting. Ear dry matter distribution increased rapidly after heading and the distribution ratio was 42-49% in pots and 52-62% in field. Although regression equations to predict dry matter distribution to different parts of rice plant were satisfactory for individual experiment, the application to different experiment was not appropriate.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.4
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• pp.384-398
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• 2015

In this paper, the high-resolution Weather Research and Forecasting/Noah-MultiParameterization (WRF/Noah-MP) modeling system is configured for the Cheongmicheon Farmland site in Korea (CFK), and its performance in land and atmospheric simulation is evaluated using the observed data at CFK during the 2014 special observation period (21 August-10 September). In order to explore the usefulness of turning on Noah-MP dynamic vegetation in midterm simulations of surface and atmospheric variables, two numerical experiments are conducted without dynamic vegetation and with dynamic vegetation (referred to as CTL and DVG experiments, respectively). The main results are as following. 1) CTL showed a tendency of overestimating daytime net shortwave radiation, thereby surface heat fluxes and Bowen ratio. The CTL experiment showed reasonable magnitudes and timing of air temperature at 2 m and 10 m; especially the small error in simulating minimum air temperature showed high potential for predicting frost and leaf wetness duration. The CTL experiment overestimated 10-m wind and precipitation, but the beginning and ending time of precipitation were well captured. 2) When the dynamic vegetation was turned on, the WRF/Noah-MP system showed more realistic values of leaf area index (LAI), net shortwave radiation, surface heat fluxes, Bowen ratio, air temperature, wind and precipitation. The DVG experiment, where LAI is a prognostic variable, produced larger LAI than CTL, and the larger LAI showed better agreement with the observed. The simulated Bowen ratio got closer to the observed ratio, indicating reasonable surface energy partition. The DVG experiment showed patterns similar to CTL, with differences for maximum air temperature. Both experiments showed faster rising of 10-m air temperature during the morning growth hours, presumably due to the rapid growth of daytime mixed layers in the Yonsei University (YSU) boundary layer scheme. The DVG experiment decreased errors in simulating 10-m wind and precipitation. 3) As horizontal resolution increases, the models did not show practical improvement in simulation performance for surface fluxes, air temperature, wind and precipitation, and required three-dimensional observation for more agricultural land spots as well as consistency in model topography and land cover data.