• Korean Membrane Journal
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• v.11 no.1
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• pp.21-28
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• 2009

We investigated the effect of organic materials on membrane fouling in advanced drinking water treatment by a hybrid module packed with granular activated carbon (GAC) outside multi-channel ceramic microfiltration membrane. Synthetic water was prepared with humic acid and kaolin to simulate natural water resouces consisting of natural organic matter and inorganic particles. Kaolin concentration was fixed at 30 mg/L and humic acid was changed as 2~10 mg/L to inspect the effect of organic matters. Periodic back-flushing using permeate water was performed for 10 sec per filtration of 10 min. As a result, both resistance of membrane fouling (Rf) and permeate flux (J) were influenced highly by concentration of humic acid. It proved that NOM like humic acid could be an important factor on membrane fouling in drinking water treatment. Turbidity and UV254 absorbance were removed up to above 97.4% and 59.2% respectively.

• Genomics & Informatics
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• v.16 no.4
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• pp.32.1-32.7
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• 2018

Ovarian cancer is one of the leading causes of cancer-related deaths in gynecological malignancies. Over 70% of ovarian cancer cases are high-grade serous ovarian cancers and have high death rates due to their resistance to chemotherapy. Despite advances in surgical and pharmaceutical therapies, overall survival rates are not good, and making an accurate prediction of the prognosis is not easy because of the highly heterogeneous nature of ovarian cancer. To improve the patient's prognosis through proper treatment, we present a prognostic prediction model by integrating high-dimensional RNA sequencing data with their clinical data through the following steps: gene filtration, pre-screening, gene marker selection, integrated study of selected gene markers and prediction model building. These steps of the prognostic prediction model can be applied to other types of cancer besides ovarian cancer.

• Macromolecular Research
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• v.12 no.6
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• pp.553-558
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• 2004

An ultrafiltration membrane (polyethersulfone, PM 10) was surface-modified by treating it with low-tem­perature plasmas of oxygen, acrylic acid (AA), acetylene, diaminocyolohexane (DACH), and hexamethyldisiloxane (HMDSO). The effects that these modifications have on the filtration efficiency of a membrane in waste water treat­ment were investigated. The oxygen, AA, and DACH plasma-treated membranes became more hydrophilic. The water contact angles ranged from < $10^{\circ}\;to\;55^{\circ}$ depending on the type of plasma and the treatment conditions. The oxygen plasma-treated membranes displayed a higher initial flux $(312-429\%),$ but lower rejection $(6-91\%),$ than did an untreated membrane. The AA plasma-treated membranes displayed lower or higher initial flux $(42-156\%),$ depending upon the treatment conditions, but higher rejection $(224-295\%)$ in all cases. The DACH plasma-treated membranes displayed lower initial flux. All of them, especially the AA plasma-treated membrane, displayed improved fouling resistance with either a slower or no flux decline. Acetylene and HMDSO plasma-treated membranes became more hydrophobic and displayed both lower initial flux and lower fouling resistance.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.1
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• pp.1-9
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• 2011

In order to investigate the cause and magnitude of scale effect occurring in the model experiments of fishing nets, five pairs of Nylon pyramid nets and one pair of PE ones in which all the two nets paired were equal each other in the factors determining their flow resistance, i. e., the ratio d/l of diameter d to length l of bars, the angle f between two adjacent bars, the attack angle q of nettings to the water flow, and the wall area S of nets, and different in the values of d and l were prepared. Then, the nets were attached to the circular steel frame alternately and their flow resistances with shapes in water were measured on the sea ascribing no turbulent flows by using the tension meter made of a block bearing for the experiment. All the Nylon nets were spreads out easily in water to form a circular cone at relatively low velocity of water and showed the resistance smaller a little in the nets with larger d and l than them with smaller d and l, because the filtration of water through meshes become easier in nets especially with larger l. But PE nettings were not spread out sufficiently on account of their small flexibility and showed higher resistance especially in them with thicker twines. Therefore, the difference in bar length or mesh size and flexibility of nettings between prototype and model nets are regarded to become factors ascribing scale effect. Especially the influence of the difference in mesh size may become large significantly in actual model experiments because the mesh size of model nets is decided at much larger value than that given by scale ratio and so the difference of mesh size between the two nets become much larger than that between nets used in this experiment.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.43-47
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• 2008

The nickel and cobalt resistance of Cupriavidus metallidurans CH34 is mediated by the CnrCBA efflux pump encoded by the cnrYHXCBAT metal resistance determinant. The products of the three genes cnrYXH transcriptionally regulate expression of cnr. CnrY and CnrX are membrane-bound proteins, probably functioning as anti-sigma factors, whereas CnrH is a cnr-specific extracytoplasmic functions (ECF) sigma factor. The periplasmic domain of CnrX (residues 29-148) was cloned as a N-terminal His-tagged protein, expressed in Escherichia coli, and purified using affinity chromatography and gel filtration. The molecular mass was estimated to be about 13.6kDa by size exclusion chromatography, corresponding to a monomer. The tetragonal bipyramid crystals were obtained by mixing an equal volume of protein in 50mM Tris-HCl, pH 7.5, 1% glycerol, 100mM NaCl, 1mM DTT, and the reservoir solution of 15% w/v PEG 2000, 100mM lithium chloride at 277K in 2-4 days using hanging drop vapor diffusion. The protein concentration was 24mg/ml. The crystal that diffracted to $2.42{\AA}$ resolution belongs to space group $P4_1\;or\;P4_3$ with unit cell parameters of $a=b=32.14{\AA},\;c=195.31{\AA},\;{\alpha}={\beta}={\gamma}=90^{\circ}$, with one molecule of CnrX in the asymmetric unit.

• Membrane and Water Treatment
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• v.8 no.3
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• pp.279-292
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• 2017

This study was aimed at ultrafiltration (UF) as a pretreatment before reverse osmosis (RO) within the scheme of hybrid reverse osmosis-multistage flush (RO-MSF) desalination. Seawater at elevated temperature (after MSF heat-exchangers) was used as a feed in this process. The pretreatment system was represented as a set of functionally-linked technological segments such as: UF filtration, backwashing, chemical- enhanced backwashing, cleaning, waste disposal, etc. The process represents the sequences of operating cycles. The cycle, in turn, consists of the following unit operations: filtration, backwashing and chemical-enhanced backwashing (CEB). Quantitative assessment was based on the following indicators: normalized permeability, transmembrane pressure, specific energy and water consumption, specific waste generation. UF pre-treatment is accompanied by the following waste streams: $W1=1.19{\times}10$ power of $-2m^3$ (disposed NaOCl with 0.0044% wt.)/$m^3$ (filtrate); $W2=5.95{\times}10$ power of $-3m^3$ (disposed $H_2SO_4$ with 0.052% wt.)/$m^3$(filtrate); $W3=7.26{\times}10$ power of $-2m^3$ (disposed sea water)/$m^3$ (filtrate). Specific energy consumption is $1.11{\times}10$ power of $-1kWh/m^3$ (filtrate). The indicators evaluated over the cycles with conventional (non-chemical) backwashing were compared with the cycles accompanied by CEB. A positive impact of CEB on performance indicators was demonstrated namely: normalized UF resistance remains unchanged within the regime accompanied by CEB, whereas the lack of CEB results in 30% of its growth. Those quantitative indicators can be incorporated into the target function for solving different optimization problems. They can be used in the software for optimisation of operating regimes or in the synthesis of optimal flow- diagram. The cycle characteristics, process parameters and water quality data are attached.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.8
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• pp.775-780
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• 2008

Sludge conditioning is widely used to improve aggregation and dewaterability of waste sludge in sludge treatment processes. The study aims to examine quantitative correlations between coagulant dosage and sludge cake dewaterability using three kinds of coagulants, such as an aluminum sulfate, a ferric chloride, and a poly aluminum chloride(PAC). When an aluminum sulfate, a ferric chloride, and a PAC were injected with 0.79$\sim$1.19 mmol/g, 0.61$\sim$1.25 mmol/g TSS, and 0.21$\sim$0.39 mmol/g TSS, respectively, specific resistances to filtration of the sludge were decreased at 95.0% or more. This study shows that the correlation between coagulant dosage per g sludge(D) and normalized specific resistance to filtration(R) could be expressed by the exponential functions.

• Journal of Life Science
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• v.15 no.1 s.68
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• pp.94-99
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• 2005

Sixty four bacterial colonies which were able to oxidize the manganese were isolated from soil samples in Mokcheon and Ochang area. Among them, one bacterial strain was selected for this study based on its higher manganese oxidation, and this selected bacterial strain was identified as Aeromonas sp. MN44 through physiological-biochemical test and analysis of its 16s rRNA sequence. Aeromonas sp. MN44 was able to utilize lactose but did not utilize various carbohydrates as a sole carbon source. Aeromonas sp. MN44 showed a very sensitive to antibiotics such as kanamycin, chloramphenicol, ampicillin, tetracycline and spectinomycin, and heavy metal such as cadmium. But this strain showed a high resistance up to mg/ml unit to heavy metals such as lithium and manganese. Optimal manganese oxidation condition of Aeromonas sp. MN44 was pH 7.4 and manganese oxidation activity was inhibited by proteinase K and boiling treatment. So, we concluded that this factor was protein. The manganese oxidizing factor produced by Aeromonas sp. MN44 was partial purified by ammonium sulfate precipitation, DEAE-Toyopearl 650M ion exchange chromatography and Sephadex gel filtration chromatography. Its molecular mass was about 113 kDa.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.12
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• pp.1822-1829
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• 2003

Porcine colostrum and milk were separated into the acid-soluble and casein fractions by acidification followed by centrifuge. The acid-soluble fraction of porcine colostrum was further separated by liquid chromatography and anisotropic membrane filtration. Trypsin and chymotrypsin inhibitory capacity in porcine colostrum, milk and their components was determined by incubating bovine trypsin or chymotrypsin in a medium containing their corresponding substrates with or without addition of various amounts of porcine colostrum, porcine milk or their components. The inhibition of insulin-like growth factor I (IGF-I) and epidermal growth factor (EGF) degradation in pig small intestinal contents by porcine colostrum was measured by incubating iodinated IGF-I or EGF with the intestinal contents with or without addition of porcine colostrum. Degradation of labeled IGF-I or EGF was determined by monitoring the generation of radioactivity soluble in 30% trichloroacetic acid (TCA). The results showed that porcine colostrum had high levels of trypsin and chymotrypsin inhibitory activity and increased the stability of IGF-I and EGF in pig intestinal contents. The inhibitory activity declined rapidly during lactation. It was also found that trypsin and chymotrypsin inhibitory activity and the inhibition on IGF-I and EGF degradation in the acid-soluble fraction were higher than that in the casein fraction. Heat-resistance study indicated that trypsin inhibitors in porcine colostrum survived heat treatments of $100^{\circ}C$ water bath for up to 10 min, but exposure to boiling water bath for 30 min significantly decreased the inhibitory activity. Compared with the trypsin inhibitors, the chymotrypsin inhibitors were more heatsensitive. Separation of the acid-soluble fraction of porcine colostrum by liquid chromatography and anisotropic membrane filtration revealed that the trypsin and chymotrypsin inhibitory capacity was mainly due to a group of small proteins with molecular weight of 10,000-50,000. In conclusion, the present study confirmed the existence of high levels of protease inhibitors in porcine colostrum, and the inhibition of porcine colostrum on degradation of milk-borne growth factors in the pig small intestinal tract was demonstrated for the first time.

• Journal of Wetlands Research
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• v.16 no.3
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• pp.347-353
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• 2014

This work was performed to find the effect of operation parameters on the permeate flux through the activated sludge dynamic layer, and to indicate the relationship between the water quality of supernatant and flux based on the results. Since the effluent can be obtained through steady and stable formation of cake layer in the bio-filter media system, it is an important subject to keep and control microbes with activated state in the bio-reactor. Filtration resistance was drastically increased at more than 18000mg/L of MLSS. With filtration time continued, the flux was gradually decreased and the water qualities of supernatant monitored by turbidity and TOC were also deteriorated. This phenomenon indicated that the organic materials generated by microbes and accumulated in the reactor might affect the flux in the system. In addition, the decrease of flux was simultaneously observed in the sludge volume index. When SVI was controlled from 150 to 250, the flux was also decreased. The proper aeration time was recommended to 30 to 60 seconds in this system. In order to operate this system steadily, therefore, the control of water quality of supernatant and SVI should be proceeded.