Ultrasonic Degradation of Endocrine Disrupting Compounds in Seawater and Brackish Water

So Young Park,Jong Sung Park,Ha Yoon Lee,Ji Yong Heo,Yeo Min Yoon,Kyung Ho Choi,Nam Guk Her 대한환경공학회 2011 Environmental Engineering Research Vol.16 No.3

In this study, a series of experiments was conducted on the relative degradation of commonly known endocrine-disrupting compounds such as bisphenol A (BPA) and 17α-ethinyl estradiol (Ee₂) in a single-component aqueous solution using 28 and 580 kHz ultrasonic reactors. The experiments were conducted with three different types of model water: deionized water (DI), synthetic brackish water (SBW), and synthetic seawater (SSW) at pH 4, 7.5, and 11 in the presence of inert glass beads and humic acids. Significantly higher sonochemical degradation (93-97% for BPA) occurred at 580 kHz than at 28 kHz (43-61% for BPA), regardless of water type. A slightly higher degradation was observed for Ee₂ compared to that of BPA. The degradation rate of BPA and Ee₂ in DI water, SBW, and SSW after 30 min of ultrasound irradiation at 580 kHz increased slightly with the increase in pH from 4 (0.073-0.091 min-1 for BPA and 0.081-0.094 min-1 for Ee₂) to 7.5 (0.087-0.114 min-1 for BPA and 0.092?0.124 min-1 for Ee₂). In contrast, significant degradation was observed at pH 11 (0.149-0.221 min-1 for BPA and 0.147-0.228 min-1 for Ee₂). For the given frequencies of 28 and 580 kHz, the degradation rate increased in the presence of glass beads (0.1 mm and 25 g) for both BPA and Ee₂: 0.018-0.107 min-1 without beads and 0.052-0.142 min-1 with beads for BPA; 0.021-0.111 min-1 without beads and 0.054-0.136 min-1 with beads for Ee₂. A slight increase in degradation of both BPA and Ee₂ was found as the concentration of dissolved organic carbon (DOC, humic acids) increased in both SBW and SSW: 0.107-0.115 min-1 in SBW and 0.087-0.101 min-1 in SSW for BPA; 0.111-0.111 min-1 in SWB and 0.092-0.105 min-1 in SSW for Ee₂. After 30 min of sonicating the humic acid solution, DOC removal varied depending on the water type: 27% (3 mg L-1) and 7% (10 mg L-1) in SBW and 7% (3 mg L-1) and 4% (10 mg L-1) in SSW.

Protective Effects of N-acetylcystenine and Selenium against Doxorubicin Toxicity in Rats

Yeo-sung Yoon,Sun-don Kim,Min-hye Lee,Heung-shik S.Lee,In-se Lee,Je-kyung Sung,Eun-sung Park 대한수의학회 2003 Journal of Veterinary Science Vol.4 No.2

Effects of N-acetylcysteine and Selenium against Doxorubicin Toxicity in RatsEun-sung Park, Sun-don Kim1, Min-hye Lee, Heung-shik S. Lee, In-se Lee, Je-kyung Sung and Yeo-sung Yoon*

변환-역변환을 통한 자기회귀이동평균모형에서의 예측값 추정

여인권,조혜민,Yeo, In-Kwon,Cho, Hye-Min 한국통계학회 2008 응용통계연구 Vol.21 No.3

시계열자료 분석에 있어 주요 목적 중에 하나는 미래에 대한 예측 값을 추정하는 것이다. 이 논문에서는 정상자기회귀이동평균 모형에서 변환-역변환 방법을 이용하여 예측값을 구하는 과정에서 발생하는 문제에 대해 알아보고 회귀분석에서 제안되었던 smearing 추정방법을 시계열분석에서 사용할 수 있도록 붓스트랩을 이용하여 수정한 추정법을 소개한다. Yeo-Johnson 변환 (2000)을 이용한 KOSDAQ지수의 수익률 실증분석을 통해 기존에 사용되고 있는 방법의 문제점과 제안된 방법의 적절성에 대해 고찰해 보았다. One of main goals of time series analysis is to estimate prediction of future values. In this paper, we investigate the bias problem when the transformation and back- transformation approach is applied in ARMA models and introduce a modified smearing estimation to reduce the bias. An empirical study on the returns of KOSDAQ index via Yeo-Johnson transformation was executed to compare the performance of existing methods and proposed methods and showed that proposed approaches provide a bias-reduced estimation of the prediction value.

국내외 수용가 맞춤형 수력발전시스템 현대화개발 및 실증

오민환(Min-Hwan Oh),신기석(Ki-Seok Shin),임재황(Jae-Hwang Lim),윤여창(Yeo-Chang Yun),김현아(Hyun-Ah Kim),강석원(Seok-Won Kang),백종명(Jong-Myung Paik),이준용(Jun-Yong Lee) 대한전기학회 2017 대한전기학회 학술대회 논문집 Vol.2017 No.10

Effects of Dilute Acid Pretreatment on Enzyme Adsorption and surface Morphology of Liriodendron tulipifera

Byeong Cheol Min,Bon Wook Koo,Ki Seob Gwak,Hwan Myeong Yeo,Joon Weon Choi,In Gyu Choi 한국목재공학회 2011 목재공학 Vol.39 No.2

In this study, dilute acid pretreatment of Liriodendron tulipifera was performed for enzymatic hydrolysis. As the pretreatment temperature was increased, enzymatic hydrolysis and enzyme adsorption yield also increased. The highest enzymatic hydrolysis yield was 57% (gig) and enzyme adsorption was 44% (gig). Enzymatic hydrolysis yield was determined with weight loss of pretreated biomass by enzyme, and enzyme adsorption was a percentage of enzyme weight attaching on pretreated biomass compared with input enzyme weight. When L. tulipifera was pretreated with 1% sulfuric acid at 160℃ for 5 min., hemi-cellulose was significantly removed in pretreatment, but the lignin contents were constant. Other changes in surface morphology were detected on biomass pretreated at 160℃ by a field emission scanning electron microscope (FESEM). A large number of spherical shapes known as lignin droplets were observed over the entire biomass surface after pretreatment. Hemicellulose removal and morphological changes improved enzyme accessibility to cellulose by increasing cellulose exposure to enzyme. It is thus evidence that enzyme adsorption is a significant factor to understand pretreatment effectiveness.

변환된 자기회귀이동평균 모형에서의 예측구간추정

조혜민,오승언,여인권,Cho, Hye-Min,Oh, Sung-Un,Yeo, In-Kwon 한국통계학회 2007 응용통계연구 Vol.20 No.3

시계열자료를 분석하는데 있어 중요한 목적 중에 하나가 미래값에 대한 예측이다. 일반적으로 자기회귀이동평균모형에서는 백색잡음이 정규분포를 따른다는 가정 하에서 모수의 추론과 예측 및 예측구간의 추정이 이루어지고 있다. 그러나 자료가 이러한 가정을 만족하지 않는 경우, 자료를 가정에 맞게 변환시킨 후 분석하는 방법을 생각해 볼 수 있다. 이 논문에서는 변환된 자료를 분석하여 얻은 결과를 이용하여 본래의 척도에서의 미래값에 대한 예측구간을 추정하는 문제에 대해 알아본다. 제안하는 방법에서는 먼저 적절한 변환을 이용하여 자료를 정규가정을 만족하도록 변환시키고 변환된 자료를 이용하여 미래값에 대한 예측구간을 추정한 후, 역변환을 이용하여 예측구간을 추정한다. 이 논문에서는 시계열분석에서 모델링이 상대적으로 어려운 왜도의 문제를 해결하기 위해 Yeo-Johnson 변환을 중심으로 한 방법론을 소개한다. 모의실험 결과 제안된 방법에 의한 단측예측구간의 포함확률이 변환을 사용하지 않은 구간보다 명목수준에 가까운 것을 확인하였다. One of main aspects of time series analysis is to forecast future values of series based on values up to a given time. The prediction interval for future values is usually obtained under the normality assumption. When the assumption is seriously violated, a transformation of data may permit the valid use of the normal theory. We investigate the prediction problem for future values in the original scale when transformations are applied in ARMA models. In this paper, we introduce the methodology based on Yeo-Johnson transformation to solve the problem of skewed data whose modelling is relatively difficult in the analysis of time series. Simulation studies show that the coverage probabilities of proposed intervals are closer to the nominal level than those of usual intervals.

Arsenic Removal from Water Using Various Adsorbents

Shahnawaz Sinha,Gary Amy,Yeo Min Yoon,Nam Guk Her 대한환경공학회 2011 Environmental Engineering Research Vol.16 No.3

The equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water. The adsorbents tested included magnetic ion exchange resins (MIEX), hydrous ion oxide particles (HIOPs), granular ferric hydroxide (GFH), activated alumina (AA), sulfur modified iron (SMI), and iron oxide-coated microsand (IOC-M), which have different physicochemical properties (shape, charge, surface area, size, and metal content). The results showed that adsorption equilibriums were achieved within a contact period of 20 min. The optimal doses of adsorbents determined for a given equilibrium concentration of Ceq = 10 μg/L were 500 mg/L for AA and GFH, 520-1,300 mg/L for MIEX, 1,200 mg/L for HIOPs, 2,500 mg/L for SMI, and 7,500 mg/L for IOC-M at a contact time of 60 min. At these optimal doses, the rate constants of the adsorbents were 3.9, 2.6, 2.5, 1.9, 1.8, and 1.6 1/hr for HIOPs, AA, GFH, MIEX, SMI, and IOC-M, respectively. The presence of silicate significantly reduced the arsenic removal efficiency of HIOPs, AA, and GFH, presumably due to the decrease in chemical binding affinity of arsenic in the presence of silicate. Additional experiments with natural types of water showed that, with the exception of IOC-M, the adsorbents had lower adsorption capacities in ground water than with surface and deionized water, in which the adsorption capacities decreased by approximately 60-95%.

Purification and Characterization of Helicobacter pylori ${\gamma}$-Glutamyltranspeptidase

Song, Jae-Young,Choi, Yeo-Jeong,Kim, Jeong-Min,Kim, Yoo-Ree,Jo, Jin-Seong,Park, Jin-Sik,Park, Hee-Jin,Song, Yun-Gyu,Lee, Kon-Ho,Kang, Hyung-Lyun,Baik, Seung-Chul,Youn, Hee-Shang,Cho, Myung-Je,Rhee, Kw The Korean Society for Microbiology 2011 Journal of Bacteriology and Virology Vol.41 No.4

Gamma-glutamyltranspeptidase (GGT) was purified to electrophoretic homogeneity from the cell extract of H. pylori. The purified enzyme consisted of heavy and light subunits with molecular weights of 38 kDa and 21 kDa, respectively. N-terminal amino acid sequence of heavy and light subunits revealed that H. pylori GGT was processed into 3 parts for a signal peptide of 27 amino acid residues, a heavy subunit of 352 residues, and a light subunit of 188 residues during translation. The reaction rate for hydrolysis of ${\gamma}$-GpNA was 84.4 ${\mu}mol/min$ per milligram of protein, and that for the ${\gamma}$-glutamyl transfer from ${\gamma}$-GpNA to gly-gly was 23.8 ${\mu}mol/min$ per milligram of protein. The apparent Km values of H. pylori GGT for ${\gamma}$-glutamyl compounds were on the order of $10^{-3}$ to $10^{-4}$ M and those for acceptor peptides and amino acids were on the order of $10^{-1}$ to $10^{-2}$ M. The GGT protein kept approximately 80% of the initial enzymatic activity on incubation at $60^{\circ}C$ for 15 min. The optimum temperature and pH for reactions of both hydrolysis and transpeptidation were $40^{\circ}C$ and 9.0, respectively. The transpeptidation and hydrolysis reactions catalyzed by H. pylori GGT were strongly inhibited by L-Gln and moderately inhibited by L-Ala, L-Ser, ${\beta}$-chloro-L-Ala, and L-Glu. These results demonstrated that the biochemical properties of H. pylori GGT are different from those of other bacterial GGTs. Further, H. pylori GGT might degrade glutathione in the gastric mucous layer of humans if the enzyme could be secreted in the bacterial niches.

A study on the removal of sulfate and nitrate from the wet scrubber wastewater using electrocoagulation

Jo, Eun-young,Park, Seung-Min,Yeo, In-seol,Cha, Jae-doo,Lee, Ju Yeol,Kim, Young-Hee,Lee, Tae-Kwon,Park, Chan-gyu Informa UK (Taylor Francis) 2016 Desalination and Water Treatment Vol.57 No.17

<P>Wet scrubber is widely used to remove pollutants from a furnace flue gas or from other gas streams. However, high cost for the treatment or exchange of contaminated washed water is one of the problems. Electrocoagulation (EC) is an electrochemical method for treating polluted water, whereby sacrificial anodes dissolve to produce active coagulant precursors in the solution. This technology can be used for the removal of color, anionic contaminants, and colloidal particles. The goal of the present study was evaluation of EC process for treatment of wet scrubber wastewater and optimization of the process. In this study, the influence of electrode material and electrode distance on removal efficiency (%) of nitrate, sulfate, and total suspended solids (TSS) was investigated with synthetic wastewater. Using an Al electrode, 60.6% of nitrate, 50.0% of sulfate, and 96.8% of TSS were removed by EC treatment within 30 min. In case of Fe electrode, 69.7% of nitrate, 75.0% of sulfate, and 98.8% of TSS were removed. The treatment efficiency for real wet scrubber wastewater was evaluated with Fe electrode. After 180 min of EC treatment, 50% of color, 40% of nitrate, 40% of sulfate, and 95% of TSS were removed, respectively. All these results give clear evidence that EC process can effectively reduce the TSS, nitrate, and sulfate ions from wet scrubber wastewater.</P>

Fabrication and Characterization of an Anodic Aluminum Oxide Template with Variations in the Anodization Solution for pH Sensors

Jo, Ye-Won,Lee, Sung-Gap,Yeo, Jin-Ho,Kim, Kyeong-Min American Scientific Publishers 2016 Journal of nanoscience and nanotechnology Vol.16 No.11

<P>In this study, an electrolyte-dielectric-metal (EDM) device incorporating a high-k (high dielectric constant) Al2O3 sensing template from porous anodic aluminum-oxide (AAO) was fabricated through a two-step anodizing process for pH detection. In order to change the morphologies of the AAO template, the anodization solution was varied by controlling the electrolyte. Getting the AAO template having a structure through this experiment was EDM measure the pH sensitivity changes according to the surface area. AAO templates were characterized by X-ray diffraction and field-emission scanning electron microscopy (FE-SEM). The anodic aluminum oxide template for pH sensors went through the following steps: 1st anodizing step at 90 V for 6 h (0.3 M, H3PO4); 2nd anodizing step at 90 V for 1 min (H3PO4 0.3 M); and pore widening for 30 min. The device displayed a good sensitivity of 54.2 mV/pH.</P>