• Journal of Korean Society of Transportation
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• v.32 no.4
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• pp.369-379
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• 2014

The Statistical regression model has been used to construct crash prediction models, despite its limitations in assuming data distribution and functional form. In response to the limitations associated with the statistical regression models, a few studies based on non-parametric methods such as neural networks have been proposed to develop crash prediction models. However, these models have a major limitation in that they work as black boxes, and therefore cannot be directly used to identify the relationships between crash frequency and crash factors. A genetic programming model can find a solution to a problem without any specified assumptions and remove the black box effect. Hence, this paper investigates the application of the genetic programming technique to develope the crash prediction model. The data collected from the Gyeongbu expressway during the past three years (2010-2012), were separated into straight and curve sections. The random forest technique was applied to select the important variables that affect crash occurrence. The genetic programming model was developed based on the variables that were selected by the random forest. To test the goodness of fit of the genetic programming model, the RMSE of each model was compared to that of the negative binomial regression model. The test results indicate that the goodness of fit of the genetic programming models is superior to that of the negative binomial models.

• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.41-47
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• 1999

To investigate the combined effect of gamma ray irradiation and NaCl treatment on Tradescantia somatic cell pink mutations, potted plants of Tradescantia 4430 were evenly sprayed with NaCl solution(170mM) 24 hours before irradiation(NaCl+${\gamma}$) and after irradiation(${\gamma}$+NaCl). Irradiation doses were 0.3, 0.5, 1.0 and 2.0 Gy of gamma-ray. The plants irradiated only with gamma radiation were used as control group(CT). Frequency of pink mutation increased linearly with irradiation close and the peak interval of elevated mutation frequencies appeared during 6∼12 days aver irradiation in all the experimental groups. The slope of dose-response curve in CT was 5.99($r^2$=0.99), while it were 4.55($r^2$=0.98) in NaCl+${\gamma}$ and 4.33($r^2$=0.99) in ${\gamma}$+NaCl. It seemed that pre- and post-treatment of NaCl had a protective effect it against radiation-induced cell damages since it decreased the slope value by more than 24%. It is suggested that protective effect on DNA damages can be invoked in irradiated stamen hair cells by NaCl treatment.

• Radiation Oncology Journal
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• v.8 no.2
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• pp.183-188
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• 1990

Between January 197l and December 1987, 113 patients with nasopharyngeal cancer (NPC) were treated by radiation therapy with or without chemotherapy in the department of Radiation Oncology, Yonsei University Hospital. There were 19 patients under thirty years of age. The histology was undifferentiated carcinoma in $68\%$ of the younger patients as compared to $47\%$ of the older patients. Sex, stage, initial symptoms and treatment modalities differed little from those of older patients. In younger patients, the initial complete response rate was $79\%$ as compared to older patients with $54\%$, distant metastases were more common and the overall five year survival rate was not significantly different between the two age groups ($33.7\%$ for the young vs. $37.4\%$ for the old). The five year survival rates for stage III and IV were $60.0\%$ and $24.5\%$, respectively. Histologic subtype was not correlated with survival. The best survival was found only in patients who obtained a complete clearance of disease after radiation therapy.

• Journal of Pharmaceutical Investigation
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• v.39 no.1
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• pp.73-78
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• 2009

A simple LC-MS/MS method of rabeprazole in human plasma was developed and validated. Rabeprazole and Internal standard (I.S), omeprazole, were extracted from human plasma by liquid liquid extraction, chromatographic separation of rabaprazole in plasma was achieved at $45^{\circ}C$ with a Shiseido UG120 $C_{18}$ column and methanol-10 mM ammonium acetate buffer (pH 9.42 with ammonium water), as mobile phase. Rabeprazole produced a protonated precursor ion [$(M+H)^+$] at m/z 360.10 and corresponding product ion at m/z 242.21. Internal standard produced a protonated precursor ion [$(M+H)^+$] at 346.09 and corresponding product ion at m/z 198.09. This method showed linear response over the concentration range of $1{\sim}500\;ng/mL$ with correalation coefficient greater than 0.99. The lower limit of quantitation (LLOQ) using 0.2 mL plasma was 1 ng/mL, which was sensitive enough for pharmacokinetics studies. The method was specific and validated with a limit of quantitation of 1 ng/mL. The intra-day and inter-day precision and accuracy were acceptable for all samples including the LLOQ. The applicability of the method was demonstrated by analysis of plasma after administration of a single 10 mg dose to 36 healthy subject. From the plasma rabeprazole concentration versus time curves, the mean $AUC_t$ (The area under the plasma concentration-time curve from time 0 to 12 hr ) was $691.36{\pm}321.88\;ng{\cdot}hr/mL$, $C_{max}$ (maximum plasma drug concentration) of $353.21{\pm}131.52\;ng/mL$ reached $3.4{\pm}1.1\;hr$ after adiministration. The mean biological half-life of rabeprazole was $1.37{\pm}0.75\;hr$. Based on the results, this simple method could readily be used in pharmacokinetics studies.

• The Journal of Engineering Geology
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• v.27 no.4
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• pp.429-438
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• 2017

Monte Carlo N-Particle (MCNP) modeling algorithm based on the Monte Carlo method was used to perform the simulation of neutron logging in order to increase the reliability and utilization of neutron logs applied in geological and resource engineering fields. To perform the simulation using MCNP, we used a realistic three-dimensional configuration of neutron sonde and formation. Validation of the modeling was confirmed by comparing the calibration curves of sonde manufacture with those calculated by MCNP modeling. After the validation, lithology effects, pore fluid effects, borehole diameter change, casing effect, and effects of borehole water level were investigated through modeling experiments. Numerical tests indicate that changes in neutron count ratio according to the lithology were quantitatively understood. In case of a borehole with a diameter of 3 inches, ratio of counting rates was higher than expected to be interpreted as borehole fluid has small effects on neutron logging. Effect of casing was also small in general, particular when porosity increases. Since modeling results above the groundwater level showed a tendency opposite to those below the groundwater level, neutron logs can be used to detect groundwater level. The modeling results simulated in this study for various borehole environments are expected to be used for data processing and interpretation of neutron log.

• Journal of the Korean Institute of Gas
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• v.22 no.4
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• pp.39-48
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• 2018

This study presents optimal design of gas lift considering composition of reservoir oil and injected gas which can affect gas lift performance in offshore oil reservoir. Reservoir simulation was conducted by using reservoir models which were built in accordance with API gravity of oil. The results of simulation reveal that oil production rate is considerably increased by gas lift when the reservoir productivity decrease. As a results of response curve analysis for gas lift using well models, gas injection rate to improve the production rate increases as the API gravity of oil decreases and the specific gravity of injected gas increases. The optimal design of gas lift was carried out using multiple lift valves. Consequently, gas lift can be operated at relatively low injection pressure because of decrease in injection depth in comparison to the single lift valve design. The improved oil production rates were analyzed by coupling between reservoir model and well model. As a results of the coupling, it is expected that natural gas injection in the heavy oil reservoir is the most efficient method for improving oil production by gas lift.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2997-3003
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• 2009

The pharmacological profile of KR-31081, a nonpeptide $AT_1$ selective angiotensin receptor antagonist, was investigated by receptor binding studies, functional in vitro assays with rabbit aorta. KR-31081 inhibited the specific binding of $[^{125}I]\;[Sar^1,\;Ile^8]$-angiotensin II to human recombinant $AT_1$ receptor with an 8.6-fold greater potency than losartan ($IC_{50}$: 1.43 and 12.3 nM, respectively), but it did not inhibit the binding of [$^{125}I$] CGP 42112A to human recombinant $AT_2$ receptor ($IC_{50}$: higher than $10{\mu}M$ for both). The Hill coefficient for the competition curve of KR-31081 against $AT_1$ receptor was not significantly different from unity (0.99). Scatchard analysis showed that KR-31081 interacted with human recombinant $AT_1$ receptor in a competitive manner, as with losartan. In functional studies with rabbit aorta, KR-31081 competitively inhibited the contractile response to angiotensin II ($pK_B$ values: 8.66) with 20-70% decrease in the maximum contractile responses, unlike losartan that showed competitive antagonism without any change in the maximum contractile responses to angiotensin II ($pA_2$ values: 7.59). These results suggest that KR-31081 is a highly potent $AT_1$ selective angiotensin II receptor antagonist with a mode of insurmountable antagonism to be developed as the exploratory potential of this compound.

• Journal of Pharmaceutical Investigation
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• v.35 no.5
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• pp.323-328
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• 2005

The purpose of the present study was to evaluate the bioequivalence of two torasemide tablets, Torem tablet (Roche Korea Co., Ltd., Korea, reference drug) and Boryung Torsemide tablet (Boryung Pharmaceutical Co., Ltd., Korea, test drug), according to the guidelines of Korea Food and Drug Administration (KFDA). After adding an internal standard (furosemide) to human serum, serum samples were extracted using 5 mL of ethyl acetate. Compounds were analyzed by reverse-phase HPLC method with UV detection. This method showed linear response over the concentration range of 0.05 ug/mL with correlation coefficient of 0.999. The lower limit of quantitation using 0.5 mL of serum was 0.05 ug/mL which was sensitive enough for pharmacokinetic studies. Twenty-eight healthy male Korean volunteers received each medicine at the torasemide dose of 20 mg in a $2{\times}2$ crossover study. There was a one-week washout period between the doses. Serum concentrations of torasemide were monitored by an HPLC-UV for over a period of 12 hr after the administration. $AUC_{t}$(the area under the serum concentration-time curve from time zero to 12 hr) was calculated by the linear trapezoidal rule method. $C_{max}$ (maximum serum drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the serum concentration-time data. Analysis of variance was carried out using logarithmically transformed $AUC_{t}$ and $C_{max}$. No significant sequence effect was found for all of the bioavailability parameters indicating that the crossover design was properly performed. The 90% confidence intervals of the $AUC_{t}$ ratio and the $C_{max}$ ratio for Boryung Torsemide/Torem were log 0.97-10g 1.03 and log 0.93log 1.12, respectively. These values were within the acceptable bioequivalence intervals of log 0.80-log 1.25. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating Boryung Torsemide tablet and Torem tablet are bioequivalent.

• Journal of Nutrition and Health
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• v.45 no.2
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• pp.192-200
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• 2012

Fruits are generally recommended for a balanced meal, as they are good sources of vitamins, minerals, and fiber, which may improve blood glucose control. However, fruits have simple sugars with a wide glycemic index (GI) range. The purpose of this study was to analyze the sugar content and composition and to determine the glycemic indices of the most frequently consumed fruits in Korea, including apple, tangerine, pear, water melon, persimmon, grape, oriental melon, and peach. The sugar content and composition of the fruits were analyzed by high performance anion-exchange chromatography (Dinonex model DX-600). The GI of the fruits was measured in 13 healthy subjects (seven females and six males) after permission was received from the University Hospital institutional review board (KHU-IRB 1114-06). The subjects consumed 50 g of glucose as a reference and carbohydrate portions of eight fruits. Blood samples were collected at 0, 30, 60, 90, and 120 min after consuming the fruits. The GI values for the fruits were calculated by expressing the increase in the area under the blood glucose response curve for each subject. As a result, the total sugar contents of 100 g fruits were: grape (13.9 g), apple (12.3 g), persimmon (11.9 g), oriental melon (11.2 g), watermelon (9.3 g), tangerine (8.9 g), peach (8.6 g), and pear (8.3 g). The GI values of the fruits were as follows: GI value of peach ($56.5{\pm}14.17$), watermelon ($53.5{\pm}18.07$), oriental melon ($51.2{\pm}18.14$), tangerine ($50.4{\pm}15.16$), grape ($48.1{\pm}14.05$), persimmon ($42.9{\pm}18.92$), pear ($35.7{\pm}14.38$), and apple ($33.5{\pm}11.92$). These findings will help individuals choose fruit for controlling blood sugar.

• Journal of Nutrition and Health
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• v.42 no.8
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• pp.714-722
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• 2009

The principal objective of this study was to determine the effects of leucine on body weight reduction in high fat diet-induced overweight rats. To induce overweight, six-month-old male Sprague-Dawley rats (n = 80) were divided into 8 groups; one group of 10 rats was fed on a normal fat diet and the remaining 70 rats were fed on a high-fat diet (40% of energy as fat) for 14 weeks. Then, 10 rats fed on the normal fat diet and another 10 rats fed on the high fat diet were sacrificed to identify overweight induction. The remaining 60 rats were divided randomly into 6 groups according to body weight and fed on one of the diets with different dietary fat levels (9.6% or 40% of energy as fat) and leucine levels (0, 0.6 or 1.2 g/kg BW) for the following 5 weeks of experiments. The body weight loss in the Leu-administered groups (0.6 g, 1.2 g/kg BW) was significantly higher than those of Leu non-administered groups. The perirenal fat pad weights in the Leu-administered groups were significantly lower than those of the Leu non-administered groups. Of the hepatic enzymes, glucose-6-phosphate dehydrogenase (G6PDH) activities were reduced significantly in the Leu-administered groups than in the Leu non-administered groups. With the oral glucose tolerance test (OGTT), the incremental areas under the curve of the glucose response (IAUC) of the Leu-administered groups were significantly lower than those of the Leu non-administered groups. The fasting glucose concentration and HOMA-IR of the Leu-administered groups were significantly lower than those of the Leu non-administered groups. In conclusion, the results of this study suggest that one of the possible mechanisms of leucine in the observed body weight reduction might involve the inhibition of lipogenic enzyme activities such as glucose-6-phosphate dehydrogenase, rather than the activation of lipolysis enzymes. Additionally, leucine adminstration resulted in improved glucose metabolism.