• Title/Summary/Keyword: Da-sik

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Preparation and Characterizations of poly(arylene ether sulfone)/SiO2 Composite Membranes for Polymer Electrolyte Fuel Cell (고분자 전해질 연료전지(PEFC)용 poly(arylene ether sulfone)/SiO2 복합막의 제조 및 특성분석)

  • Shin, Mun-Sik;Kim, Da-Eun;Park, Jin-Soo
    • Membrane Journal
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    • v.27 no.2
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    • pp.182-188
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    • 2017
  • Sulfonated poly(arylene ether sulfone) (SPAES)-3-mercaptopropyl silica gel (3MPTSG) composite membranes with improved oxidative stability were prepared for polymer electrolyte fuel cell application. It has been reported that ether part of main chain of aromatic hydrocarbon based membranes were weak to radical attack to decrease membrane durability. In this study, the hydrophilic inorganic particles were introduced by minimizing a decrease in ion conductivity and increasing an oxidative stability. The composite membranes were investigated in terms of ionic conductivity, ion exchange capacity (IEC), FT-IR, TGA and contact angle, etc. As a result, increasing amount of the 3MPTSG resulted in decrease in proton conductivities and water uptakes at 100% R.H. but enhanced thermal and oxidative stabilities.

Biological Activity of Human Dimeric Hyperglycosylated Erythropoietin (dHGEPO) Fusion Proteins

  • Naidansuren, Purevjargal;Min, Kwan-Sik
    • Reproductive and Developmental Biology
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    • v.34 no.4
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    • pp.289-297
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    • 2010
  • Erythropoietin (EPO) is a glycoprotein hormone secreted from primarily cells of the peritubular capillary endothelium of the kidney, and is responsible for the regulation of red blood cell production. We constructed and expressed dimeric cDNAs in Chinease hamster ovary (CHO) cells encoding a fusion protein consisting of 2 complete human EPO domains linked by a 2-amino acid linker (Ile-Asp). We described the activity of dimeric hyperglycosylated EPO (dHGEPO) mutants containing additional oligosaccharide chains and characterized the function of glycosylation. No dimeric proteins with mutation at the $105^{th}$ amino acid were found in the cell medium. Growth and differentiation of the human EPO-dependent leukemiae cell line (F36E) were used to measure cytokine dependency and in vitro bioactivity of dHGEPO proteins. MIT assay at 24 h increased due to the survival of F36E cells. The dHGEPO protein migrated as a broad band with an average molecular mass of 75 kDa. The mutant, dHGEPO, was slightly higher than the wild-type (WT) dimeri-EPO band. Enzymatic N-deglycosylation resulted in the formation of a narrow band with a molecular mass twice of that of of monomeric EPO digested with an N-glycosylation enzyme. Hematocrit values were remarkably increased in all treatment groups. Pharmacokinetic analysis was also affected when 2.5 IU of dHGEPO were intravenously injected into the tails of the mice. The biological activity and half-life of dHGEPO mutants were enhanced as compared to the corresponding items associated the WT dimeric EPO. These results suggest that recombinant dHGEPO may be attractive biological and therapeutic targets.

Function of the Tethered rec-eCG in Rat and Equine Receptors

  • Park, Jong-Ju;Jargal, Naidansuren;Yoon, Jong-Taek;Min, Kwan-Sik
    • Reproductive and Developmental Biology
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    • v.33 no.4
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    • pp.229-236
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    • 2009
  • The glycoprotein hormone family represents a class of heterodimers, that includes the placental hormone equine chorionic gonadotropin (eCG) and the anterior pituitary hormones- follitropin (FSH), lutropin (LH), and thyrotropin (TSH). The 4 hormones are heterodimers, with a common $\alpha$-subunit and unique $\beta$-subunits. eCG is the most heavily glycosylated of the known pituitary and placental glycoprotein hormones. Recent observations using single chain glycoprotein hormone analogs in which, the $\beta$-and $\alpha$-subunits are linked, implied that heterodimeric-like quaternary configuration is not a prerequisite for receptor/signal transduction. To study the function and signal transduction of tethered rec-eCG, a single chain eCG molecule was constructed and rec-eCG protein was produced. Molecular mass of the single chain is about 45 kDa. All mice were ovulated by tethered rec-eCG treatment. The dual activity of tethered rec-eCG was determined in receptor cell lines of nonequid species; in fact, this dual activity was proven in species other than horse. Tethered rec-eCG in equids does not bind to FSH receptors, suggesting that eCG is primarily an LH-like hormone in the horse. Taken together, these data suggest that tethered rec-eCG has dual activity in nonequid species in vitro. However, it has only LH-like activity in equid species in vitro.

Apoptosis of Rat Embryonic Midbrain Cells in Ochratoxin A-induced Microcephaly

  • Hong, Jin-Tae;Park, Kui-Lea;Han, Soon-Young;Park, Ki-Sook;Kim, Hyung-Sik;Oh, Se-Dong;Lee, Rhee-Da;Jang, Seung-Jae
    • Journal of Food Hygiene and Safety
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    • v.15 no.1
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    • pp.41-45
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    • 2000
  • Induction of DNA fragmentation of rat embryonic midbrain cells was studied to see whether apoptosis plays a role in OTA-induced microcephaly observed in cultured rat whole embryos during embryogenesis. We first cultured whole embryos (prepared from day 9.5 gestation rats) for 48 hrs with OTA and found that OTA induced microcephaly in cultured rat whole embryos. We also examined whether the microcephaly seen in cultured whole embryos is partially related to the increase of apoptosis of undifferentiated embryonic midbrain cells. Embryonic midbrain cells were prepared from day 12 gestation rat embryos, and cultured in the mixture media of Dulbecco's modified eagle's medium nutrient and Ham's F12 (1:1) containing 10% Nuserum, 100 $\mu\textrm{g}$/ml of streptomycin and 100 units/ml of penicillin for 96 hrs. Induction of DNA fragmentation was increased by 0.25-1 $\mu\textrm{g}$/ml OTA in a dose dependent manner in the embryonic midbrain cells. We also tested whether increase of apoptosis by OTA would be associated with change of apoptosis-related proteins (TNF-$\alpha$ and P$^{53}$ ) level in embryonic midbrain cells. OTA also increased TNF-$\alpha$ and P$^{53}$ levels. These results show that OTA induced microcephaly in cultured whole embryos and this effect may be at least a part due to the induction of apoptosis and apoptosis-related protein levels of undifferentiated embryonic midbrain cells.

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Electrochemical Studies of Carbon Felt Electrode Modified Under Airless Conditions for Redox Flow Batteries

  • Noh, Tae Hyoung;Kim, Min Young;Kim, Da Hye;Yang, Seung Hoon;Lee, Jong Ho;Park, Hong Sik;Noh, Hee Sook;Lee, Moo Sung;Kim, Ho Sung
    • Journal of Electrochemical Science and Technology
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    • v.8 no.2
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    • pp.155-161
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    • 2017
  • Carbon felts were prepared under various thermal conditions to improve the electrochemical properties of vanadium redox flow batteries. The number of C-O and/or C-OH functional groups on the surface of the electrodes treated under airless conditions was much larger than that of the untreated and partially oxygen-treated electrodes. The carbon felt treated under airless conditions had the lowest surface area. The overall kinetic properties of the redox reaction were greatly improved for the carbon felt treated under airless conditions; i.e., the reversibility of the anodic and cathodic reactions associated with the $VO_2{^+}/VO^{2+}$ couple became more reversible. Single-cell tests indicated that the carbon felt exhibited an excellent discharge capacity of $3.1Ah{\cdot}g^{-1}$ at $40mA{\cdot}cm^{-2}$, and the corresponding Coulombic, voltage, and energy efficiencies were 89.5%, 91.8%, and 82.2%, respectively.

Efficient Grid Resource Scheduling Model with Resource Reliability Measurement (자원 신뢰성 측정을 통한 효율적인 그리드 자원 스케줄링 모델)

  • Park, Da-Hye;Lee, Jong-Sik
    • Journal of the Korea Society for Simulation
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    • v.15 no.4
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    • pp.129-136
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    • 2006
  • Grid computing has been appeared for solving large-scaled data which are not solved by a single computer. Grid computing is a new generation platform which connects geographically distributed heterogeneous resources. However, gathering heterogeneous distributed resources produces many difficult problems. Especially. to assure resource reliability is one of the most critical problems. So, we propose a grid resource scheduling model using grid resource reliability measurement. We evaluate resource reliability based on resource status data and apply it to the grid scheduling model in DEVSJAVA modeling and simulation. This paper evaluates parameters such as resource utilization, job loss and average turn-around time and estimates experiment results of our model in comparison with those of existing scheduling models such as a random scheduling model and a round-robin scheduling model. These experiment results showed that the resource reliability measurement scheduling model provides efficient resource allocation and stable Job processing in comparison with a random scheduling model and a round-robin scheduling model.

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InhA-Like Protease Secreted by Bacillus sp. S17110 Inhabited in Turban Shell

  • Jung, Sang-Chul;Paik, Hyoung-Rok;Kim, Mi-Sun;Baik, Keun-Sik;Lee, Woo-Yiel;Seong, Chi-Nam;Choi, Sang-Ki
    • Journal of Microbiology
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    • v.45 no.5
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    • pp.402-408
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    • 2007
  • A strain producing a potent protease was isolated from turban shell. The strain was identified as Bacillus sp. S17110 based on phylogenetic analysis. The enzyme was purified from culture supernatant of Bacillus sp. S17110 to homogeneity by ammonium sulfate precipitation, SP-Sepharose, and DEAE-Sepharose anion exchange chromatography. Protease activity of the purified protein against casein was found to be stable at pH 7 to pH 10 and around $50^{\circ}C$. Approximately 70% of proteolytic activity of the enzyme was detected either in the presence of 100 mM SDS or Tween 20. The enzyme activity was enhanced in the presence of $Ca^{2+},\;Zn^{2+},\;Mg^{2+}$, but was inhibited by EDTA, indicating that it requires metal for its activity. The purified enzyme was found to be a monomeric protein with a molecular mass of 75 kDa, as estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography. The purified enzyme was analyzed through peptide fingerprint mass spectra generated from matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS) and a BLAST search, and identified as immune inhibitor A (inhA) deduced from nucleotide sequence of B. cereus G9241. Since InhA was identified as protease that cleave antibacterial proteins found in insect, inhA-like protease purified from Bacillus sp. S17110 might be pathogenic to sea invertebrates.

The effect of otago exercise-based fall prevention education activities on balance, fall efficacy and activities of daily living in the subacute stroke patients: A randomized controlled clinical trial (오타고운동 기반 낙상예방교육활동이 아급성 뇌졸중 환자의 균형, 낙상 효능감 및 일상생활동작능력에 미치는 영향: 무작위 대조군 임상 연구)

  • Yoon, Hyun Sik;Han, Kyu Bum;Oh, Seung In;Lee, Da Bee;Song, Ha Hee;Song, Jeong Eun;Cha, Young Joo
    • Journal of Korean Physical Therapy Science
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    • v.27 no.1
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    • pp.1-8
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    • 2020
  • Background: This study analysed the effect of the fall prevention education activities on balance, fall efficacy, activities of daily living (ADL) of sub-acute stroke patients. Design: Randomized controlled trial. Methods: The subjects of the study were 24 subacute patients, who have onset period of less than 6 months. They are randomly allocated in the conventional therapy group (n=12) and fall prevention education group (n=12) and observed with frequency for 5 times a week for four weeks. Measuring took place before and after the experiment leading to following results of the Fall efficacy scale (FES), Berg balance scale (BBS) and Functional Independence Measure (FIM). Results: FES, BBS and FIM score was significantly greater in the post-test than in the pre-test in both groups (p<0.01). Independent t-test confirmed that the fall prevention education group showed much greater improvement change in the FES, BBS and FIM score than conventional therapy group (p<0.05). Conclusion: The present study demonstrated the importance of clinical contribution of the fall prevention education in the individuals with subacute stroke patients to the balance, fall efficacy and ADL following the stroke rehabilitation.

Influence of Performance and Microbial Community by Internal pH Control on Anaerobic Digestion of Food Waste Leachate (음폐수 이용 혐기성 소화의 내부 pH 조절에 따른 바이오가스 전환율 비교 및 미생물 군집도 분석)

  • Yun, Yeo-Myeong;Cho, Si-Kyung;Jeong, Da-Young;Lee, Eun-Jin;Huh, Kwan-Yong;Shin, Dong-Hyuk;Lee, Chang-Kyu;Shin, Hang-Sik
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.8
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    • pp.571-578
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    • 2013
  • In this study, the performance and microbial community of anaerobic digestion fed by food waste leachate at low organic loading rate were investigated with and without internal pH control. Experimental results show that similar biogas yield was achieved in both reactors regardless of increase in pH, the concentrations of free ammonia and volatile fatty acids in case of without internal pH controlled one. The results of a methanogenic community analysis by Polymerase Chain Reaction and Denaturing Gradient Gel Electrophoresis revealed that the apparent preponderance of Methanosarcina sp. could be one of reasons for the maintenance of reactor stability.

Purification, Partial Characterization, and Immunoassay of Vitellogenin from Marbled Sole (Limanda yokohamae)

  • Kim Dae-Jung;Jung Jee-Hyun;An Cheul-Min;Jee Young-Ju;Min Kwang-Sik;Kim Yoon;Han Chang-Hee
    • Fisheries and Aquatic Sciences
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    • v.8 no.4
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    • pp.213-219
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    • 2005
  • Vitellogenin (VTG) was purified from the blood plasma of estradiol-17$\beta$ ($E_2$)-treated male marbled sole (Limanda yokohamae) using gel filtration and anion exchange chromatography. The purity of the marbled sole VTG (msVTG) was confirmed by polyacrylamide gel electrophoresis (SDS-PAGE) and N-terminal amino acid sequencing. The purified msVTG was used to produce monoclonal and polyclonal antibodies in mice and rabbits, respectively, and the specificity of the polyclonal antisera for msVTG was confirmed by Western blot analysis. The antibodies cross­reacted with a protein of molecular mass approximately 160 kDa in the plasma samples of mature female marbled sole. No cross-reactivity was observed with the plasma of male fish. A direct non-competitive sandwich enzyme-linked immunosorbent assay (ELISA) was developed using the monoclonal anti-msVTG and polyclonal anti-msVTG antibodies, with purified msVTG as the standard protein. The values of the intra- and inter-assay variations were within the ranges of $8.l-9.8\%$ and $8.5-12.2\%$, respectively. The sensitivity was about 0.3 ng/mL. Serial dilutions of plasma from mature female sole reacted with the msVTG-antibodies in the sandwich ELISA, whereas the plasma from male fish did not. The results indicate that the maturation status of female marbled sole can be identified using a sandwich ELISA for msVTG.