• Title/Summary/Keyword: Partition Coefficient

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Software Development Effort Estimation Using Partition of Project Delivery Rate Group (프로젝트 인도율 그룹 분할 방법을 이용한 소프트웨어 개발노력 추정)

  • Lee, Sang-Un;No, Myeong-Ok;Lee, Bu-Gwon
    • The KIPS Transactions:PartD
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    • v.9D no.2
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    • pp.259-266
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    • 2002
  • The main issue in software development is the ability of software project effort and cost estimation in the early phase of software life cycle. The regression models for project effort and cost estimation are presented by function point that is a software sire. The data sets used to conduct previous studies are of ten small and not too recent. Applying these models to 789 project data developed from 1990 ; the models only explain fewer than 0.53 $R^2$(Coefficient of determination) of the data variation. Homogeneous group in accordance with project delivery rate (PDR) divides the data sets. Then this paper presents general effort estimation models using project delivery rate. The presented model has a random distribution of residuals and explains more than 0.93 $R^2$ of data variation in most of PDR ranges.

Examination of Bioconcentration of a New Algicide, Thiazolidinedione Derivative (TD49) to Marine Organisms (신규 살조제 Thiazolidinedione 유도체 (TD49)의 해양생물에 대한 생물 농축도 조사)

  • Shin, Jun-Jae;Kim, Si-Wouk;Cho, Hoon;Kim, Seong-Jun
    • KSBB Journal
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    • v.27 no.2
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    • pp.91-96
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    • 2012
  • In this study, a newly synthesized thiazolidinedione derivative, TD49 with a highly selective algicide to red tide, was examined in order to evaluate the bioconcentration on aquatic organisms of coast. BAF (accumulation of TD49 by aquatic food chain) and BCF (accumulation of TD49 by sea water) were examined employing the shrimp (Fenneropenaeus chinensis) as the feed organism, and the olive flounder Paralichthys olivaceus as a consumer in marine ecosystem. Bioconcentration degree in sea water showed that the order in P. olivaceus was viscera > gill > muscle. The average BCF values of TD49 were 67.70, 63.32 and 20.25 at viscera, gill and muscle, respectively. Bioaccumulation degree using feed showed that the order in the organs of P. olivaceus was viscera > gill > muscle. The average BAF values of TD49 were 175.89, 114.88 and 32.59 at viscera, gill and muscle, respectively. When compared with two results, the accumulation by the food and water was higher than that by water. After the elimination experiment in sea water, the TD49 concentration was 2.81 nmole/g in the viscera and were not found in the gill and the muscle. More than 50% of the accumulated TD49 were eliminated from viscera in 7 days and all the accumulated TD49 were eliminated from gill and muscle in 7 days. On the other hand, the octanol/water partition coefficient (log $K_{ow}$) was measured to be 3.66 and experimental BCF of this study was 67.7.

Prediction of the Toxicity of Dimethylformamide, Methyl Ethyl Ketone, and Toluene Mixtures by QSAR Modeling

  • Kim, Ki-Woong;Won, Yong Lim;Hong, Mun Ki;Jo, Jihoon;Lee, Sung Kwang
    • Bulletin of the Korean Chemical Society
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    • v.35 no.12
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    • pp.3637-3641
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    • 2014
  • In this study, we analyzed the toxicity of mixtures of dimethylformamide (DMF) and methyl ethyl ketone (MEK) or DMF and toluene (TOL) and predicted their toxicity using quantitative structure-activity relationships (QSAR). A QSAR model for single substances and mixtures was analyzed using multiple linear regression (MLR) by taking into account the statistical parameters between the observed and predicted $EC_{50}$. After preprocessing, the best subsets of descriptors in the learning methods were determined using a 5-fold cross-validation method. Significant differences in physico-chemical properties such as boiling point (BP), specific gravity (SG), Reid vapor pressure (rVP), flash point (FP), low explosion limit (LEL), and octanol/water partition coefficient (Pow) were observed between the single substances and the mixtures. The $EC_{50}$ of the mixture of DMF and TOL was significantly lower than that of DMF. The mixture toxicity was directly related to the mixing ratio of TOL and MEK (MLR $EC_{50}$ equation = $1.76997-1.12249{\times}TOL+1.21045{\times}MEK$), as well as to SG, VP, and LEL (MLR equation $EC_{50}=15.44388-19.84549{\times}SG+0.05091{\times}VP+1.85846{\times}LEL$). These results show that QSAR-based models can be used to quantitatively predict the toxicity of mixtures used in manufacturing industries.

Synthesis and In Vitro Properties of Prednisolone 21-Sulfate Sodium as a Colon-Specific Prodrug of Prednisolone

  • Doh, Min-Ju;Jung, Yun-Jin;Kim, In-ho;Kong, Hye-Sik;Kim, Young-Mi
    • Archives of Pharmacal Research
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    • v.26 no.4
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    • pp.258-263
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    • 2003
  • Colon-specific delivery of glucocorticoids is highly desirable for the efficient treatment of inflammatory bowel disease. We synthesized prednisolone 21-sulfate sodium (PDS) as a colon-specific prodrug of prednisolone (PD) and investigated its properties using rats as test animals. We expected that introduction of sulfate ester as a sodium salt might increase the hydrophilicity and restrict the absorption in the GI tract. If PDS is stable and nonabsorbable in the upper intestine, it will be delivered to the colon as an intact form, where it hydrolyze by the sulfatase to release PD. Compared with PD, the solubility of PDS increased and the apparent partition coefficient decreased greatly. PDS was stable on incubation with pH 1.2 and 6.8 buffer solutions and with the contents of the stomach and small intestine. On incubation with the cecal contents, PDS decreased to 9.6% of the dose in 10 h producing PD. The amount of PD increased to give a maximum 54% of the dose and decreased. As a control, when PD was incubated with the cecal contents, it decreased to 29% of the dose in 8 h, which implied that reduction of PD proceeded under such conditions. These results suggested that hydrolysis of PDS took place to produce and accumulate PD, which decreased by reduction as the incubation period extended. Our results suggested that PDS can be a promising colon-specific prodrug of PD, and sulfate ester group might serve as a potential colon-specific promoiety, especially for the drugs which are resistant to reduction in the colon.

Effects of Water Content and Temperature on Equilibrium Distribution of Organic Pollutants in Unsaturated Soil (토양내 유기독성물질의 평형분포에 미치는 토양수분과 온도의 영향)

  • Koo, Ja Kong;Shin, Hang Sik;Kim, Dong Ha
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.8 no.3
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    • pp.119-128
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    • 1988
  • The purpose of this research is to quantify the effects of water content(0.3~1.255%) and temperature ($4{\sim}40^{\circ}C$) on the equilibrium distribution of toxic organic pollutant in unsaturated soil. The priority pollutants, Dichloromethane and 1, 1, 1-Trichloroethane were selected as toxic organic pollutants and the Korean decomposed granite soil as the experimental soil media. Two models were developed on the basis of shapes of soil water distribution in unsaturated soil and compared; complete surface coating(model I) vs. spot clustering (model II). From the experiment, a large decrease in the values of effective partition coefficient ($K_{eff}$) was observed as the water content increased. As the temperature increased, the $K_{eff}$ values decreased, and this effect was magnified at lower water contents. The values of $K_{eff}$ were correlated better with the estimated values using model II. Thus it was experimentally proved that the soil water tends to enclose the soil grain partly at lower water contents.

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Estimation of Physical-Chemical Property and Environmental Fate of Benzoyl peroxide Using (Q)SAR

  • Kim, Mi-Kyoung;Kim, Su-Hyon;Heekyung Bae;Sanghwan Song;Hyunju Koo;Jeon, Seong-Hwan;Na, Jin-Gyun;Park, Kwangsik;Lee, Moon-Soon
    • Proceedings of the Korea Society of Environmental Toocicology Conference
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    • 2002.10a
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    • pp.154-154
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    • 2002
  • Benzoyl peroxide is a High Production Volume Chemical, which is produced about 1,375 tons/year in Korea as of 2001 survey. The substance is mainly used as initiators in polymerization, catalysts in the plastics industry, bleaching agents for flour and medication for acne vulgaris. The substance is one of seven chemicals of which human health and environmental risks are being assessed by National Institute of Environmental Research (NIER) under the frame of OECD SIDS Program. In this study, Quantitative Structure-Activity Relationships (QSAR) is used for getting adequate information on the physical-chemical property and the environmental fate of this chemical. For the assessment of benzoyl peroxide, models such as MPBPWIN for vapor pressure, KOWWIN for octanol/water partition coefficient, HENRYWIN for Henry's Law constant, AOPWIN for photolysis and BCFWN for bioconcentration factor (BCF) were used. These (Q)SAR model programmes were worked by using the SHILES (Simplified Molecular Input Line Entry System) notations. The physical-chemical properties and the environmental fate of benzoyl peroxide were estimated as followed : vapor pressure =0.00929 Pa, Log Kow = 3.43, Henry's Law constant = 0.00000354 atm-㎥/mole at 25 $^{\circ}C$, the half-life of photodegradation = 3 days, bioconcentration factor (BCF) = 92

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Modeling Fate and Transport of Organic and Nitrogen Species in Soil Aquifer Treatment-(I) Model Development and Verification (토양/대수층 처리(soil aquifer treatment)에서 유기물과 질소화합물 제거와 이송 모델링-(I) 모델 개발 및 검증)

  • Kim Jung-Woo;Kim Jeong-Kon;Cha Woo-Suk;Choi Hee-Chul
    • Journal of Soil and Groundwater Environment
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    • v.10 no.3
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    • pp.9-15
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    • 2005
  • Soil aquifer treatment is a water reuse technology that secondary or tertiary treated wastewater is infiltrated into the aquifer in which physical and biochemical reactions occur. Major consideration in SAT is the removal and transport of DOC and nitrogen species. In this study, reaction mechanism in SAT was examined considering nitrification, denitrification and organic oxidation. In addition, SAT modeling system was developed as the reaction mechanism was applied to groundwater flow and transport model. In verification of the reaction module by 1-dimensional unsaturated soil column test, the experimental data of all of the species, ammonium, nitrate, DOC and DO, were well matched with the simulation results. In sensitivity analysis, ammonium partition coefficient, dissolved oxygen inhibition constant and biomass decay rate affect ammonium, DOC and DO concentration of effluent, respectively.

Uncertainty Analysis of a Pharmacokinetic Modeling for Inhalation Exposure of Benzene from the Use of Groundwater at Dwelling (거주지의 지하수사용에서 유래한 벤젠의 흡입노출에 대한 동적약리학 모델의 불확실성 분석)

  • 김상준;이현호;박지연;이유진;유동한;양지원
    • Journal of Soil and Groundwater Environment
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    • v.9 no.1
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    • pp.28-38
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    • 2004
  • This study presents the result of uncertainty and sensitivity analysis of a pharmacokinetic model which describes the distribution and removal of benzene at each organ when an indivisual inhales indoor contaminated air with benzene originated from groundwater. The pharmacokinetic model simulates the distribution of benzene deposited in organs of human body through inhalation of contaminated indoor air as well as degradation-metabolism in liver. This study focused on the uncertainty problem induced from the use of the single values for blood flow, partition coefficient, degradation constant, volume, etc. of each organ which was due to a lack of knowledge about these parameters or their measurements. To solve this problem, uncertainty analysis on the pharmacokinetic model was conducted simultaneously which would help understanding the risk assessment associated with VOCs.

Hybrid Barriers of Iron and Modified-bentonite for the Remediation of Multi-contaminated Water (복합오염물질 제거를 위한 철과 개량 벤토나이트의 복합층에 관한 연구)

  • Cho, Hyun-Hee;Park, Jae-Woo
    • Journal of Korean Society on Water Environment
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    • v.20 no.5
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    • pp.512-519
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    • 2004
  • Hybrid barriers using reduction and immobilization were tested to remediate the groundwater contaminated with multi-pollutants in this study. Iron filings and HDTMA(hexadecyltrimethylammonium)-bentonite were simulated in columns to assess the performance of hybrid barriers for remediation of trichloroethylene(TCE)-contaminated water. TCE reduction rate for the mixture of iron filings and HDTMA-bentonite was about 7 times higher than that for iron filings, only suggesting the reduction of TCE was accelerated when HDTMA-bentonite was mixed with iron filings. TCE reduction rate for the two layers of iron and HDTMA-bentonite was nearly similar to that for iron filings alone, but the partition coefficient($K_d$) for the two layers was 4.5 times higher than for that iron filings only. TCE was immobilized in the first layer with HDTMA-bentonite, and then dechlorinated in the second layer with iron filings. HDTMA-bentonite may contribute to the increase in TCE concentration on iron surface so that more TCE can be reduced. Also, TCE removal in the hybrid barriers was not affected by chromate and naphthalene while the reduction rate of TCE with the co-existing contaminants by iron filings was significantly decreased. Significant TCE removal in this research indicates that the proposed hybrid barrier system has the potential to become the effective remediation alternative during the occurrence of oil shock. Also, if subsurface environments are contaminated with multi-pollutants that contain non-reducible compounds as well as reducible compounds such as TCE, the conventional reactive barriers cannot be applied to this subsurface environment, while the proposed hybrid system can be applied successfully.

Stability and Bioavailability on Prodrug of 5-Flurouracil (I). Synthesis, Physicochemical Properties, Stabilities and Antitumor Activities of 1-Glycyloxymethyl-5-fluorouracil Hydrochloride (5-Fluorouracil의 Prodrug에 대한 안정성 및 생체이용율에 관한 연구(I). 1-Glycyloxymethyl-5-fluorouracil HCl의 제조, 물리화학적 성질, 안정성 및 항암효과)

  • Jee, Ung-Kil;Lee, Gye-Won;Park, Mork-Soon
    • 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.

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