• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2441-2445
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• 2015

Background: Several risk factors leading to malignant transformation of hydatidiform moles have been described previously. Many studies showed that prophylactic chemotherapy for high risk hydatidiform moles could significantly decrease the incidence of malignancy. Thus, it is essential to discover a breakthrough to determine patients with high risk malignancy so that prophylactic chemotherapy can be started as soon as possible. Objectives: Development of a scoring system of risk factors as a predictor of hydatidiform mole malignant transformation. Materials and Methods: This research is a case control study with hydatidiform mole and choriocarcinoma patients as subjects. Multiple logistic regression was used to analyze the data. Odds ratios (OR), attributable at risk (AR : OR-1) and risk index ($ARx{\beta}$) were calculated for develoipment of a scoring system of malignancy risk. The optimal cut-off point was determined using receiver operating characteristic (ROC) curve. Results: This study analyzed 34 choriocarcinoma cases and 68 benign hydatidiform mole cases. Four factors significantly increased the risk of malignancy, namely age ${\geq}35$ years old (OR:4.41, 95%CI:1.07-16.09, risk index 5); gestational age ${\geq}$ 12weeks (OR:11.7, 95%CI:1.8-72.4, risk index 26); uterine size greater than the gestational age (OR:10.2, 95%CI:2.8-36.6, risk index 21); and histopathological grade II-III (OR:3.4, 95%CI:1.1-10.6, risk index 3). The lowest and the highest scores for the risk factors were zero and 55, respectively. The best cut-off point to decide high risk malignancy patients was ${\geq}31$. Conclusions: Malignant transformation of hydatidiform moles can be predicted using the risk scoring by analyzing the above four parameters. Score ${\geq}31$ implies high risk patients so that prophylactic chemotherapy can be promptly administered for prevention.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.534-539
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• 2010

The adsorptive removal of organic sulfur compounds including tert-butylmercaptane(TBM), tetrahydrothiophene(THT) and dimethylsulfide(DMS) in methane was investigated over NaY and copper-exchanged NaY(CuNaY) zeolites at 303 K and atmospheric pressure. In the ternary adsorption system, the preferential adsorption of THT over other sulfur compounds on NaY and the concurrent adsorption of all sulfur compounds on CuNaY were achieved, which could be explained by the breakthrough curve, the temperature-programmed desorption, and the apparent activation energy for desorption. The sulfur uptake capacity of CuNaY(2.90~3.20 mmol/g) was much higher than that of NaY(0.70~0.90 mmol/g). A comparative study indicated that the $Cu^{1+}$ sites and acidity of CuNaY were probably responsible for the strong interaction with sulfur atom and high sulfur uptake abilities.

• Journal of Environmental Science International
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• v.20 no.6
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• pp.729-736
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• 2011

This work is to compare the experiment results by a continuous fixed-bed adsorption of water vapor, acetone vapor, and toluene vapor on zeolite 13X (SAU) and silica-alumina (SAK). SAU and SAK have very different pore structure but similar composition as inorganic adsorbent. The relationship between the equilibrium adsorption capacity and specific pore size range were studied. Adsorption of water vapor was more suitable on SAU than SAK because SAU has relatively more developed pores around $5\;\AA$ than SAK in the pore range of $10\sim100\;\AA$. Adsorption of acetone vapor was more suitable on SAK than SAU because SAK has relatively more developed pores around $5\sim10\;\AA$ than SAK in the pore range of less than $10\;\AA$. Adsorption of toluene vapor was more suitable on SAK than SAU because SAK has relatively more developed pores in the pore range of $10\sim100\;\AA$ than SAK. Adsorption capacity of the adsorbent was closely related to the surface area generated in the specific pore size region. But it was difficult to distinguish the relationships between adsorption capacity and micro area, and the external surface area of adsorbent.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.5
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• pp.575-584
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• 2007

The adsorption capability of iron phthalocyanine derivatives were investigated by means of X-ray diffractometor (XRD), IR (infrared) spectroscopy, scanning electron microscopy (SEM) and temperature programmed desorption (TPD). According to TPD results, iron phthalocyanine derivatives showed two desorption peaks at low temperature ($100{\sim}150^{\circ}C$) and high temperature ($350{\sim}400^{\circ}C$) indicating that there were two kinds of acidities. Tetracarboxylic iron phthalocyanine (Fe-TCPC) have a stronger desorption peak (chemical adsorption) at the high temperature and a weaker desorption peak (physical adsorption) at the low temperature than iron phthalocyanine (Fe-PC). The specific surface areas of Fe-TCPC and Fe-PC were $26.46\;m^2/g\;and\;11.77\;m^2/g$, respectively. The pore volumes of Fe-TCPC and Fe-PC were $0.14\;cm^3/g\;and\;0.06\;cm^3/g$, respectively. The adsorption capability of triethyl amine calculated by breakthrough curve at 220 ppm of equilibrium concentration was 29.2 mmoL/g for Fe-TCPC and 0.8 mmoL/g for Fe-PC. The removal efficiency of dimethyl sulfide of Fe-TCPC and Fe-PC in batch experiment of 225 ppm of initial concentration were 44.9% and 28.9%, respectively. The removal efficiency of trimethyl amine of Fe-TCPC and Fe-PC in batch experiment of 118 ppm of initial concentration were approximately 100.0% and 33.9%, respectively.

• Clean Technology
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• v.18 no.3
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• pp.312-319
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• 2012

Malachite green is used a dye but malachite green is harmful toxic substance. In this study, the adsorption characteristics of zeolite has been investigated for the adsorption of malachite green dissolved in water. The effects of initial dye concentration, contact time, pH and temperature on adsorption of malachite green by a fixed amount of zeolite have been studied in batch adsorber and fixed bed. The adsorption equilibrium data are successfully fitted to the Freundlich isotherm equation in the temperature range from 25 to $45^{\circ}C$. The estimated values of k and ${\beta}$ are 23.60-46.88, 0.225-0.347, respectively. The mechanism of the adsorption process was determined from the intraparticle diffusion model. The effects of the operation conditions of the fixed bed on the breakthrough curve were investigated. When the inlet concentration and initial flow rate of malachite green are increased, the corresponding adsorption breaktime appears to decrease. Breaktime increased with increasing bed height and length of adsorption zone showed similar patterns.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.868-874
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• 2008

The Ni based adsorbent was prepared by co-precipitation method and its performance for removing carbon monoxide was investigated. Here, silica, aluminium silicate and ${\gamma}$-alumina were used for carriers of catalyst. $Ni(NO_3)_2{\cdot}6H_2O$ and $Ni(CH_3COO)_2{\cdot}4H_2O$ were utilized for Ni precursors. Precipitants were urea and citric acid. After precipitation of Ni salt on the carrier and following reduction using $H_2$ gas, adsorbent was prepared and its performance was analyzed based on EDS, TPR and XRD experiments. In accordance with change of precipitation agents, Ni salts on carrier, carriers and reduction condition. Adsorbent performance for removing carbon monoxide was investigated. The adsorbent with 54.8 wt% Ni prepared using urea precipitant under reduction condition at $500^{\circ}C$ for 3 h exhibited the best CO removal performance.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.499-504
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• 2009

Erythrosine is used a food coloring, ink and dye, etc. but erithrosine is rarely used in United States due to its known hazards. The adsorption characteristics of erythrosine by granular activated carbon were investigated in the batch adsorber and the packed column. The adsorptivity of activated carbon for erythrosine were largely improved by pH control. When the pH was 11 in the sample, the erythrosine could be removed 98% of initial concentration. It was estabilished that the adsorption equilibrium of erythrosine on granular activated carbon was successfully fitted by Freundlich isotherm equation in the concentration range from 10mg/L to 1,000mg/L. The characteristics of breakthrough curve of activated carbon packed column depend on the design variables such as initial concentration, bed height, and flow rate.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.70-79
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• 2022

Biodiesel production has attracted attention as a sustainable source of fuel and is a competitive alternate to diesel engines. The glycerol that is produced as a by-product is generally discarded as waste and can be converted to green chemicals such as acetins to increase bio-diesel profitability. Acetins find application in fuel, food, pharmaceutical and leather industries. Batch experiments and analysis have been previously conducted for synthesis of acetins using glycerol esterification reaction aided by sulfated metal oxide catalysts (SO₄^2-/CeO₂-ZrO₂). The aim of this study was to optimize process parameters: effects of mole ratio of reactants (glycerol and acetic acid), catalyst concentration and reaction temperature to maximize glycerol conversion/acetin selectivity. The optimum conditions for this reaction were determined using response surface methodology (RSM) designed as per a five-level-three-factor central composite design (CCD). Statistica software 10 was used to analyze the experimental data obtained. The optimized conditions obtained were molar ratio - 1:12, catalyst concentration - 6 wt.% and temperature -90 ℃. A packed bed reactor was fabricated and column studies were performed using the optimized conditions. The breakthrough curve was analyzed.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.518-518
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• 2023

자연하천에서 오염물질의 혼합 거동은 비균일한 지형학적 요인으로 인해 매우 복잡한 특성을 나타낸다. 일반적으로 오염물질 거동 모델링에서는 수체에서의 혼합을 Fick의 법칙에 따라 유속에 의한 이송과 난류에 의한 확산으로 계산하고, 국부적인 정체현상 등에 의한 non-Fickian 혼합을 야기하는 하천의 특성을 기하학적 지형 형상으로 구현하여 실제 현상에 근접한 혼합 거동을 재현한다. 하지만 계산의 효율성을 위하여 모델링의 차원을 낮추는 경우, 하천의 지형을 경계조건으로 고려할 수 없게 된다. 특히, 1차원 모델링의 경우 하천의 비균일성을 무시하고 1개의 유선으로 간주하며, 이 경우 non-Fickian 물질이동 해석을 위한 추가적인 현상학적 해석이 필요하다. 지난 50년간, non-Fickian 물질이동 해석을 위한 다양한 현상학적 모형이 제시되어 왔다. 하천을 흐름영역과 정체영역으로 구분하고 두 개의 영역 사이의 물질교환 속도를 모델링하거나, Random walk 개념으로 물질이 이동하는 경우와 이동하지 않는 경우를 확률론적으로 모델링하거나, 물질이 정체되었을 때 다시 빠져나오는 시간을 모델링하는 경우가 그 예이다. 본 연구에서는 선행연구에서 제시한 음함수 형태의 현상학적 모형을 기반으로, 수치적 반복계산 없이 상류 경계에서 임의의 형태의 농도곡선(shape-free breakthrough curve)을 갖는 오염물질운(cloud)이 일정 거리를 유하하며 발생하는 변화를 예측할 수 있는 해를 제시한다. 본 연구의 방법론은 추적법(routing procedure)을 활용한 Fickian 혼합 해석, 전달함수(transfer function) 형태의 정체시간분포 해석, 그리고 라플라스 도메인에서의 해석해 유도를 포함한다. 본 연구에서 제시된 해는 2020년 경상북도 김천시에 위치한 감천의 4.5 km 구간에서 수행한 추적자 실험의 현장 자료를 통해 정확도를 검증하여 타당성을 입증하였다.

• Clean Technology
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• v.16 no.3
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• pp.206-212
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• 2010

The adsorption characteristics of quinoline yellow by granular activated carbon were investigated experimently in the batch adsorber and packed column. The adsorptivity of activated carbon for quinoline yellow were largely improved by acidic pH and higher temperature. When the pH was 3 at $60^{\circ}C$, quinoline yellowcould be removed 97 percent of initial concentration(10 mg/L). It was estabilished that the adsorption equilibrium of quinoline yellow on granular activated carbon was successfully fitted by Freundlich isotherm equation in the temperature range from $25^{\circ}C$ to $60^{\circ}C$. The estimated values of k and ${\beta}$ are 38.71~166.60, 0.380~0.490, respectively. The breakthrough curve of activated carbon-packed column depends on the design variables such as initial concentration, bed height, and flow rate.