• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.662-669
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• 2015

There has been an increased interest in the mitigation of wax deposition because wax, which usually accumulates in subsea oil-production systems, interrupts stable oil production and significantly increases the cost. To guarantee a required oil flow by mitigating wax deposition, we need to obtain a reliable estimation of the wax deposition. In this research, we perform simulations to understand the major mechanisms that lead to wax deposition, namely molecular diffusion, shear stripping reduction, and aging. While the model variables (shear reduction multiplier, wax porosity, wax thermal conductivity, and molecular diffusion multiplier) can be measured experimentally, they have high uncertainty. We perform an analysis of these variables and the amount of water and gas in the multiphase flow to determine these effects on the behavior of wax deposition. Based on the results obtained during this study for a higher wax porosity and molecular diffusion multiplier, we were able to confirm the presence of thicker wax deposits. As the shear reduction multiplier decreased, the thickness of the wax deposits increased. As the amount of water increased, there was also an increase in the amount of wax deposits until 40% water cut and decreased. As the amount of gas increased, the amount of wax deposits increased because of the loss of the light hydrocarbon component in the liquid phase. The results of this study can be utilized to estimate the wax deposition behavior by comparing the experiment (or field) and simulation data.

• IMMUNE NETWORK
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• v.9 no.4
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• pp.138-146
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• 2009

Background: The MHC region of the chromosome contains a lot of genes involved in immune responses. Here we have investigated the mouse NG29/Cd320 gene in the centrometrically extended MHC region of chromosome 17. Methods: We cloned the NG29 gene by RT-PCR and confirmed the tissue distribution of its gene expression by northern blot hybridization. We generated the NG29 gene expression constructs and polyclonal antibody against the NG29 protein to perform the immunofluorescence, immunoprecipitation and flow cytometric analysis. Results: The murine NG29 gene and its human homologue, the CD320/8D6 gene, were similar in the gene structure and tissue expression patterns. We cloned the NG29 gene and confirmed its expression in plasma membrane and intracellular compartments by transfecting its expresssion constructs into HEK 293T cells. The immunoprecipitation studies with rabbit polyclonal antibody raised against the NG29-NusA fusion protein indicated that NG29 protein was a glycoprotein of about 45 kDa size. A flow cytometric analysis also showed the NG29 expression on the surface of Raw 264.7 macrophage cell line. Conclusion: These findings suggested that NG29 gene in mouse extended MHC class II region was the orthologue of human CD320 gene even though human CD320/8D6 gene was located in non-MHC region, chromosome 19p13.

• Membrane Journal
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• v.7 no.1
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• pp.39-47
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• 1997

The self-designed membrane system was tested to examine the performance of the hollow fiber type polysulfone ultrafiltration(UF) membrane for the treatment of pure water(the 3rd treated water). The molecular weight cut-off's (MWCO) of the membranes used in this study were 5, 000 and 10, 000, respectively. The recovery rate, the ratio of permeate flow rate to the feed flow rate, increased as the temperature rose. The values of MWCO obtained in this study, using 2, 000 ppm polyethylene glycol and dextran solutions with various molecular weight, showed higher values than those suggested by SKI. Based on the results of the primary experiments, the water of the Gongji-stream, in which water quality is deteriorated by the inflow of domestic wastewater, was selected for the UF membrane test. Biological oxygen demand(BOD), total solids, and turbidity of the treated water had much lower values than those of the source water. Therefore, this study confirmed the possibility of the domestic water treatment using the hollow fiber type UF membrane.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.1
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• pp.39-47
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• 2009

The effects of thermo-solutal convection on mercurous chloride system of ${Hg_2}{Cl_2}$, and Ne during physical vapor transport are numerically investigated for further understanding and insight into essence of transport phenomena, For $10\;K{\le}{\Delta}T{\le}30\;K$, the growth rate slowly increases and, then is decreased gradually until ${\Delta}T$=50 K, The occurrence of this critical point near at ${\Delta}T$=30 K is likely to be due to the effects of thermo-physical properties stronger than the temperature gradient corresponding to driving force for thermal convection. For the range of $10\;Torr{\le}P_B{\le}300\;Torr$, the rate is second order-exponentially decayed with partial pressures of component B, $P_B$. For the range of $5{\le}M_B{\le}200$, the rate is second order-exponentially decayed with a function of molecular weight of component B, $M_B$. Like the case of a partial pressure of component B, the effects of a molecular weight arc: reflected through the binary diffusivity coefficients, which are intimately related with suppressing the convection flow inside the growth enclosure, i,e., transition from convection to diffusion-dominant flow mode as the molecular weight of B increases. The convective mode is near at a ground level, i,e., on earth (1 $g_0$), and the convection is switched to the diffusion mode for $0.1\;g_0{\le}g{\le}10^{-2}g_0$, whereas the diffusion region ranges from $10^{-2}g_0$ up to $10^{-5}g_0$.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06a
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• pp.508-508
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• 1996

;The growth of films have considerable interest in the field of superlattice structured multi-layer epitaxy led to realization of new devices concepts. Molecular beam epitaxy (MBE) with in situ observation by reflection high-energy electron diffraction (RHEED) is a key technology for controlled layered growth on the atomic scale in oxide crystal thin films. Also, the combination of radical oxygen source and MBE will certainly accelerate the progress of applications of oxides. In this study, the growth process of single crystal films using by MBE method is discussed taking the oxide materials of Bi-Sr-Ca-Cu family. Oxidation was provided by a flux density of activated oxygen (oxygen radicals) from an rf-excited discharge. Generation of oxygen radicals is obtained in a specially designed radical sources with different types (coil and electrode types). Molecular oxygen was introduced into a quartz tube through a variable leak valve with mass flowmeter. Corresponding to the oxygen flow rate, the pressure of the system ranged from $1{\;}{\times}{\;}10^{-6}{\;}Torr{\;}to{\;}5{\;}{\times}{\;}10^{-5}$ Torr. The base pressure was $1{\;}{\times}{\;}10^{-10}$ Torr. The growth of Bi-oxides was achieved by coevaporation of metal elements and oxygen. In this way a Bi-oxide multilayer structure was prepared on a basal-plane MgO or $SrTiO_3$ substrate. The grown films compiled using RHEED patterns during and after the growth. Futher, the exact observation of oxygen radicals with MBE is an important technology for a approach of growth conditions on stoichiometry and perfection on the atomic scale in oxide. The oxidization degree, which is determined and controlled by the number of activated oxygen when using radical sources of two types, are utilized by voltage locked loop (VLL) method. Coil type is suitable for oxygen radical source than electrode type. The relationship between the flux of oxygen radical and the rf power or oxygen partial pressure estimated. The flux of radicals increases as the rf power increases, and indicates to the frequency change having the the value of about $2{\times}10^{14}{\;}atoms{\;}{\cdots}{\;}cm^{-2}{\;}{\cdots}{\;}S^{-I}$ when the oxygen flow rate of 2.0 seem and rf power 150 W.150 W.

• IMMUNE NETWORK
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• v.2 no.1
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• pp.35-40
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• 2002

Background: CTLA-4 (Cytotoxic T Lymphocyte associated Antigen 4, CD152) has been known as a homologue of CD28, an accessory molecule providing a key costimulatory signal for successful antigen-driven activations of T lymphocyte. Most of biochemical and cell biological characteristics of the CD152 protein remain unknown while those of CD28 have been characterized in detail. Methods: In this study CD152 expression in both $CD4^+$ and $CD8^+$ PBLs was studied by using flow cytometry. And intracellular CD152 multiprotein complex was purified and used for generating antibodies recognizing proteins composing of intracellular CTLA-4 multi protein complex. Results: Level of surface expression of this molecule was peaked at 2 days of PHA stimulation in flow cytometric analysis. 40~45% of PHA blast cells were $CD152^+$ in both of two subsets at this stage and the level of expression were equivalent in both two subsets. Contrary to this surface expression, intracellular expression was peaked at day 3 and it was preferentially induced in $CD8^+$ cells and about 60% of $CD8^+$ cells were $CD152^+$ at this stage. High molecular weight (>350 kD) intacellular CD152 protein complex purified by using preparative electrophoresis were immunized into rabbits and then 3 different anti-P34PC4, anti-P34PC7 and anti-P34PC8 antibodies were obtained. Using these 3 antibodies two unknown antigens associated with intracellular CD152 multiprotein complex were found and their molecular weights were 54 kD and 75 kD, respectively. Among these, the former was present as 110 kD homodimer in non-reducing condition. Conclusion: It seemed that 34 kD intracellular CD152 molecule forms high molecular weight multiprotein complex at least with 2 proteins of 75 kD monomer and 110 kD homodimer.

• The KIPS Transactions:PartD
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• v.12D no.6 s.102
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• pp.921-930
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• 2005

In this paper, a general purpose molecular simulation system which has been developed by the author, are described. One of the most advantageous features is that the molecular simulation system can handle a coarse-grained model as well as an all-atom mode. Therefore, we can simulate mesoscopic phenomena as well as microscopic phenomena with the help of Langevin dynamics simulation and dissipative particle dynamics simulation techniques. Thus we could study anesthesia, protein folding, biopolymer flow in microchannel with single framework, which spans from microscopic to mesoscopic scales. We expect that we can also simulate many other bio/nano systems of technological importance which are not feasible by means of molecular dynamics simulation technique. Finally, performance data are shown and a bottleneck is identified for future optimization.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2447-2451
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• 2014

Human papillomavirus (HPV) is the primary etiologic agent of cervical cancer. Consideration of safety and non human leukocyte antigen restriction, protein vaccine has become the most likely form of HPV therapeutic vaccine, although none have so far been reported as effective. Since tumor cells consistently express the two proteins E6 and E7, most therapeutic vaccines target one or both of them. In this study, we fabricated DC vaccines by transducing replication-defective recombinant adenoviruses expressing E6/E7 fusion gene of HPV-16, to investigate the lethal effects of specific cytotoxic T lymphocytes (CTL) against CaSki cells in vitro. Mouse immature dendritic cells (DC) were generated from bone marrow, and transfected with pAd-E6/E7 to prepare a DC vaccine and to induce specific CTL. The surface expression of CD40, CD68, MHC II and CD11c was assessed by flow cytometry (FCM), and the lethal effects of CTL against CaSki cells were determined by DAPI, FCM and CCK-8 methods. Immature mouse DC was successfully transfected by pAd-E6/E7 in vitro, and the transfecting efficiency was 40%-50%. A DC vaccine was successfully prepared and was used to induce specific CTL. Experimental results showed that the percentage of apoptosis and killing rate of CaSki cells were significantly increased by coculturing with the specific CTL (p <0.05). These results illustrated that a DC vaccine modified by HPV-16 E6/E7 gene can induce apoptosis of CaSki cells by inducing CTL, which may be used as a new strategy for biological treatment of cervical cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3293-3299
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• 2015

Background: Arm protein lost in epithelial cancers, on chromosome X (ALEX) is a novel subgroup within the armadillo (ARM) family, which has one or two ARM repeat domains as opposed to more than six-thirteen repeats in the classical Armadillo family members. Materials and Methods: In the study, we explore the biological functions of ALEX1 in breast cancer cells. Overexpression of ALEX1 and silencing of ALEX1 were performed with SK-BR3 and MCF-7 cell lines. Cell proliferation and colony formation assays, along with flow cytometry, were carried out to evaluate the roles of ALEX1. Results: ALEX1 overexpression in SK-BR3 breast cancer cells inhibited proliferation and induced apoptosis. Furthermore, depletion of ALEX1 in MCF-7 breast cancer cells increased proliferation and inhibited apoptosis. Additional analyses demonstrated that the overexpression of ALEX1 activated the intrinsic apoptosis cascades through up-regulating the expression of Bax, cytosol cytochrome c, active caspase-9 and active caspase-3 and down-regulating the levels of Bcl-2 and mitochondria cytochrome c. Simultaneouly, silencing of ALEX1 inhibited intrinsic apoptosis cascades through down-regulating the expression of Bax, cytosol cytochrome c, active caspase-9, and active caspase-3 and up-regulating the level of Bcl-2 and mitochondria cytochrome c. Conclusions: Our data suggest that ALEX1 as a crucial tumor suppressor gene has been involved in cell proliferation and apoptosis in breast cancer, which may serve as a novel candidate therapeutic target.

• BMB Reports
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• v.39 no.6
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• pp.730-736
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• 2006

To evaluated the effect of recombinant adenovirus Ad-ODC-AdoMetDCas which can simultaneously express both antisense ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC) on cell cycle distribution in colorectal cancer cell and investigated underlying regulatory responses, human colorectal cancer cells HT-29 were cultured in RPMI 1640 medium and infected with Ad-ODC-AdoMetDCas. Cell cycle progression was detected by flow cytometry analysis. The expression levels of cell cycle regulated proteins were measured by Western blot analysis. The mRNA level of cyclin D1 was measured by RT-PCR. And a luciferase reporter plasmid of cyclin D1 promoter was constructed to observe the effect of Ad-ODC-AdoMetDCas on cyclin D1 promoter activity. The results showed that recombinant adenovirus Ad-ODC-AdoMetDCas significantly induced $G_1$ arrest, decreased levels of cyclin D1 protein and mRNA and suppressed the promoter activity. Ad-ODC-AdoMetDCas also inhibited nuclear translocation of $\beta$-catenin. In conclusion, downregulation of ODC and AdoMetDC mediated by Ad-ODC-AdoMetDCas transfection induces $G_1$ arrest in HT-29 cells and the arrest was associated with suppression of cyclin D1 expression and inhibition of $\beta$-catenin nuclear translocation. As a new anticancer reagent, the recombinant adenovirus Ad-ODC-AdoMetDCas holds promising hope for the therapy of colorectal cancers.