• Macromolecular Research
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• v.11 no.6
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• pp.514-517
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• 2003

In the solution polymerizations of methyl methacrylate with (${\alpha}$-diimine)nickel(II)/methylaluminoxane (MAO), we observed effects of the position of two methyl substituents in the ligand on both the activities of the catalysts and the polymer microstructure. ${\alpha}$-Diimine nickel(II) catalysts gave syndiotactic-rich poly(methyl methacrylate) with high molecular weight and narrow molecular weight distribution.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.259-262
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• 2005

This study aims to identify the relationship between characteristics of aqueous organic matter and chlorination by-products formation potential according to temporal effect of Juam reservoir in Sun-Choen. The molecular weight distribution and chemical composition of precursors and their relationship with disinfection by-products(DBPs) were investigated. Most of the organic matters was responsible for the major DBP precursors in the raw water are small compounds with a molecular weight less than IKDa, Aromatic contents determined by SUVA correlated well with DBPs, THMs, and HAAs formation. Especially, THMFP/DOC showed better correlation with SUVA than HAAFP/DOC and DBPFP/DOC with SUVA in Juam reservoir. Therefore, effective removal of small molecules or hydrophobic organic matter prior to disinfection process will significantly reduce the DBP concentration in the finished water.

• Journal of Biomedical Engineering Research
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• v.28 no.1
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• pp.102-107
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• 2007

In molecular imaging studies via magnetic resonance imaging, in vivo cell tracking is an important issue for the observation of cell therapy or disease behavior. High resolution imaging and longitudinal study are necessary to track the cell movement. Since the field inhomogeneity extends over several voxels, we have performed the numerical analysis using the sub-voxel method dividing a voxel of MR image into several elements and the information about the field inhomogeneity distribution around the micro-beads. We imbedded ferrite-composite micro-beads with the size of $20-150{\mu}m$ in the subject substituted for cells to induce local field distortion. In the phantom imaging with the isotropic voxel size of $200{\mu}m^3$, we could confirm the feasibility of sub-voxel tracking in a 3.0 T MRI.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.10
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• pp.1505-1512
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• 2005

Bile salt deconjugation is the most biologically significant reaction among the bacterial alterations of bile acids in the gastrointestinal tract of human and animal. The responsible enzyme, bile salt hydrolase (BSH), catalyzes the hydrolysis of glycineand/or taurine-conjugated bile salts into amino acid residues and deconjugated bile acids. Herein we review current knowledge on the distribution of BSH activity among various microorganisms with respect to their biochemical and molecular characteristics. The proposed physiological impact of BSH activity on the host animal as well as on the BSH-producing bacterial cells is discussed. BSH activity of the probiotic strains is examined on the basis of BSH hypothesis, which was proposed to explain cholesterol-lowering effects of probiotics. Finally, the potential applications of BSH research are briefly discussed.

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.789-793
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• 2003

This study focused on the optimization of the illumination method for efficient use of light energies in a photobioreactor. In order to investigate the effect of radiator position, a model simulation study was carried out using Synechococcus sp. PCC 6301 and an internally radiating photobioreactor as a model system. The efficiency of light transfer in a photobioreactor was analyzed by estimating the average light intensity in a photobioreactor. The simulation result, indicate that there exists an optimal position of internal radiators, and that the optimal position varies with radiator number and cell concentration. When light radiators are placed at the optimal position, the average light intensity is about 30% higher than that obtained by placing radiators at the circumstance or center of a photobioreactor. The method presented in this work may be useful for improving light transfer efficiency in a photobioreactor.

• The korean journal of orthodontics
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• v.9 no.1
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• pp.9-14
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• 1979

The purpose of this study was to pursue the biosynthesis of proteins of human and bovine periodontal ligaments in vitro system. The excised periodontal ligaments from human and bovine were incubated in Krebs-glucose medium containing $^3H$-proline. After incubation the incubated periodontal ligaments were homogenized and the proteins were treated with 0.1%sodium dodecyl sulfate and $\beta$-mercaptoethanol. Separation of the protein fractions was performed with agarose gel column chromatography and SDS acrylamide gel electrophoresis. The results indicated as follow: 1. Only a small percentage of $^3H$-proline incorporated into proteins was hydroxylated to $^3H$-hydroxyproline. 2. The labeled proteins in periodontal ligaments showed a wide distribution of molecular weight. But only small amounts of labeled protein were found that were characteristics of the molecular weight of collagen. 3. In all of the combined fractions of gel filtration, the degree of hydroxylation was small.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.312-315
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• 2004

In this paper we investigated the behavior of low molecular weight silicone fluids in silicone rubber by W treatment with solvent-extraction and GPC. It was shown that LMW quantity which was extracted by solvent-extraction was decreased in UV treatment time. $200{\sim}450\;g/mol$ distribution of LMW silicone fluid was contributed to recovery. It was similar to result from corona discharge. Morphological analysis was investigated by scanning electron microscope(SEM) and X-ray diffraction (XRD). The behavior of LMW silicone fluids in silicone rubber which was contributed to recovery was discussed.

• Journal of Environmental Science International
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• v.15 no.9
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• pp.829-834
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• 2006

This research aims to investigate the behavior of organic matter that causes bacterial re-growth and the formation of disinfectant by-products such as THM in water treatment, and to optimize conditions for a more efficient and conventional water facility. THM removed 51 % and 12 % through coagulation/sedimentation and filtration using a selected conventional system. In this experiment, the removal ratio of DOC was highest at 68 % when the Gt value was 42,000 and lowest at 41 % when the Gt value was 30,000. 77-84 % of total DOC was removed during coagulation/sedimentation, and 15-23 % was removed during filtration. When Gt values were between 30,000 and 66,000, over 50 % of high molecular matter above 10 K during coagulation/sedimentation was removed. Turbidity removed 98 % when the G1 value was 66,000. As the Gt value increased, the turbidity removal ratio increased. Turbidity removed over 20 % during the filtration process.

• ALGAE
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• v.27 no.3
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• pp.175-187
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• 2012

Hainan is the second largest and southernmost island of China, and it harbors many species of the family Gracilariaceae. In this study, we conducted molecular and morphological analyses of gracilarian specimens collected from Hainan Island, to clarify their taxonomic identity and phylogenetic relationships. Five species of Gracilariaceae in Hainan were determined through maximum likelihood and Bayesian analysis of rbcL sequence data. Based on the phylogenetic trees and morphology, Hainan specimens were identified as three species of Gracilaria, one species of Gracilariopsis, and one species of Hydropuntia, namely, G. salicornia, G. tenuistipitata, Gracilaria sp., Gp. bailiniae and H. edulis. This is the first report of the molecular phylogeny of Gracilariaceae on Hainan Island, and it helps to clarify the taxonomy and distribution of gracilarian species in the Asia-Pacific region.

• Membrane and Water Treatment
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• v.8 no.6
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• pp.553-562
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• 2017

In the present study, the water desalination across the penta-graphene has been explored by using molecular dynamics simulation. The penta-graphene, a new carbon allotrope, introduced theoretically in 2015. It was shown that this carbon nanostructure is slightly stiffer against buckling in comparison with the graphene nanoribbons. The effect of radius of curvature (ROC) of the membrane, pore size, and applied pressure, on water flow rate, and salt rejection is investigated. It is shown that salt rejection, and the shape of the oxygen density distribution inside the pore can be influenced by the ROC of membrane. Finally, it is shown that the ROC, and pore size of 2D membranes, play an important role in the salt rejection.