• Analytical Science and Technology
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• v.26 no.1
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• pp.34-41
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• 2013

Split-flow thin cell (SPLITT) fractionation (SF) is a rapid separation technique capable of separating colloidal particles or macromolecules into two or more fractions. SF allows fractionations in a preparative scale as sample is fed continuously. Generally SF uses a thin ribbon-like channel equipped with two flow stream splitters at the inlet and outlet of the channel. Thus there exist two flow inlets and two flow outlets at the top and bottom of the inlet and outlet of the channel, respectively. There are two operating modes in SF, conventional mode and full-feed mode (FFD). Although the resolution in the FFD mode is lower than that in the conventional mode, FFD mode has some merits. The design of the channel and operation are simpler in the FFD mode, as it does not require the feeding of the solvent. Thus there is no flow stream splitter at the channel inlet, and only one pump is needed, unlike the conventional mode, where two pumps are required for the feedings of the sample and the solvent separately. Also the sample is not diluted in the FFD mode as there is no solvent feeding, which is important for fractionation samples with low colloidal concentrations such as environmental samples. For some of environmental samples, pre-concentration is often required. In this study, a new large-scale splitter-less FFD-SF channel was implemented, where there is no splitter at the outlet as well as at the inlet of the channel. It was possible to build the channel in a much larger dimension than conventional ones, allowing much higher sample throughput (TP). The new channel was tested and optimized with polyurethane (PU) latex beads, and then applied to large-scale separation of Polyacrylate (PA).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1231-1232
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• 2011

• Journal of Life Science
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• v.27 no.10
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• pp.1199-1206
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• 2017

The lymphotoxin ${\beta}$ receptor ($LT{\beta}R$), a member of the tumor necrosis factor receptor family, plays an important role in lymphoid tissue's architecture and organogenesis. We found that $LT{\beta}R$ stimulation induced changes in stress fibers (SFs) in fibroblastic reticular cells (FRCs). MLCK and ROCK play critical roles in the regulation of SF formation in cells. The present study was performed to investigate the antifibrotic effects on SF regulation of $LT{\beta}R$ signaling, with a focus on MLCK inhibition. The effect of $LT{\beta}R$ on the SF change was analyzed using immunoblot and fluorescence assays and agonistic $anti-LT{\beta}R$ antibody-treated FRCs. In addition, we checked the level of Rho-guanosine diphosphate (GDP)/guanosine triphosphate (GTP) exchange activity with FRC lysate. Phospho-ezrin proteins acting as membrane-cytoskeleton linkers completely de-phosphorylated in agonistic $anti-LT{\beta}R$ antibody-treated FRCs. The actin bundles rearranged into SFs, where phospho-myosin light chain (p-MLC) co-localized in FRCs. ML7-treated FRCs completely blocked SFs and showed retraction and shrinkage processes comparable to those observed in agonistic $anti-LT{\beta}R$ antibody-treated cells. Inhibition of ROCK activity induced changes in the actin cytoskeleton organization; however, some SFs remained in the cells, while they were completely disrupted by MLCK inhibition with ML7. We showed that the phosphorylation of MLC was completely abolished with $LT{\beta}R$ stimulation in FRCs. When $LT{\beta}R$ was stimulated with the agonistic $anti-LT{\beta}R$ antibody, the Rho-GDP/GTP exchange activity was reduced, however, the activity was not completely abolished. Collectively, the results illustrated that MLCK was potently responsible for the SF regulation triggered via $LT{\beta}R$ signaling in FRCs.

• Radiation Oncology Journal
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• v.16 no.2
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• pp.99-106
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• 1998

Purpose : We conducted clonogenic assay using human cancer cell lines (MKN-45, PC-14, Y-79, HeLa) to investigate a correlation between the parameters of radiosensitivity. Materials and Methods : Human cancer cell lines were irradiated with single doses of 1, 2, 3, 5, 7 and 10Gy for the study of radiosensitivity and subrethal damage repair capacity was assessed with two fractions of 5Gy separated with a time interval of 0, 1, 2, 3, 4, 6 and 24 hours. Surviving fraction was assessed with clonogenic assay using $Sperman-H\"{a}rbor$ method and mathematical analysis of survival curves was done with linear-quadratic (LQ) , multitarget-single hit(MS) model and mean inactivation dose$(\v{D})$. Results : Surviving fractions at 2Gy(SF2) were variable among the cell lines, ranged from 0.174 to 0.85 The SF2 of Y-79 was lowest and that of PC-14 was highest(p<0.05, t-test). LQ model analysis showed that the values of $\alpha$ for Y-79, MKN-45, HeLa and PC-14 were 0.603, 0.356, 0.275 and 0.102 respectively, and those of $\beta$ were 0.005, 0.016, 0.025 and 0.027 respectively. Fitting to MS model showed that the values of Do for Y-79. MKN-45, HeLa and PC-14 were 1.59. 1.84. 1.88 and 2.52 respectively, and those of n were 0.97, 1.46, 1.52 and 1 69 respectively. The $\v{D}s$ calculated by Gauss-Laguerre method were 1.62, 2.37, 2,01 and 3.95 respectively So the SF2 was significantly correlated with $\alpha$, Do and $\v{D}$. Their Pearson correlation coefficiencics were -0.953 and 0,993. 0.999 respectively(p<0.05). Sublethal damage repair was saturated around 4 hours and recovery ratios (RR) at plateau phase ranged from 2 to 3.79. But RR was not correlated with SF2, ${\alpha}$, ${\beta}$, Do, $\v{D}$. Conclusion : The intrinsic radiosensitivity was very different among the tested human cell lines. Y-79 was the most sensitive and PC-l4 was the least sensitive. SF2 was well correlated with ${\alpha}$, Do, and $\v{D}$. RR was high for MKN-45 and HeLa but had nothing to do with radiosensitivity parameters. These basic parameters can be used as baseline data for various in vitro radiobiological experiments.

• Journal of radiological science and technology
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• v.37 no.2
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• pp.109-116
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• 2014

Many studies have suggested that in the era of Drug-Eluting Stents(DES) are one of the causes of In-Stent Restenosis(ISR) of Stent Fracture(SF). The present study sought to evaluate clinical characteristics of patients with stent fracture after successful DES implantation. The 4,701 patients were selected for analysis who underwent a follow-up coronary angiography irrespective of ischemic symptoms. The overall incidence of SF was 32 patients(male:female=19:13, Av. age $62.44{\pm}9.8$year, 0.68%). Fractures of Sirolimus-Eluting Stents(SES), Paclitaxel-Eluting Stents(PES), Biolimus A9-Eluting Stents(BES), Everolimus-Eluting Etents(EES), Endothelial Progenitor Cell Capture Stent(EPC) and Zotarolimus-Eluting Stents(ZES) are accounted for 19(59.4%), 9(28.1%), 2(6.3%), 1(3.1%), 1(3.1%) and 0(0%) respectively. SF developed in the left Anterior Dscending(LAD) artery in 16 patients(50%) and in complex(type B2, C) lesions in 25 patients(69.4%). Ten patients were treated with heterogenous DES, the rest being treated with either homogenous DES(3 patients), plain old balloon angioplasty(3 patients), or conservative medical treatment(17 patients). None of the patients with SF suffered from cardiac death during a follow-up period of $32.9{\pm}12.4$ months. The overall rate of DES fracture over up to 3.7 years of follow-up was 0.68% with higher incidence in SES than in PES. SF frequently occurred in the LAD artery and in complex lesions. Of the patients with SF, coronary intervention was performed only when the binary restenosis lesion was significant. During the follow-up, patients with SF have continued on combination antiplatelet therapy. There is a very low rate of major adverse cardiac events(post-detection of SF), especially cardiac death associated with SF.

• Journal of Microbiology and Biotechnology
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• v.9 no.3
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• pp.361-364
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• 1999

The binding characteristics of Anagrapha falcifera nuclear polyhedrosis virus (AtNPV) to Spodoptera frugiperda 21 (Sf21) cells were investigated. The cells displayed an affinity of 4.7×10/sup 10/M/sup -1/ with about 3,300 binding sites per cell. The biochemical nature of the AfNPV-binding sites on the cell surface was also partially identified. Our findings suggest that the binding-site moiety has a glycoprotein component, but that the direct involvement of oligosacccharides containing N-acetylglucosamine or sialic acid residues in binding is unlikely, and that AfNPV entry into Sf21 cells may be via receptor-mediated endocytosis.

• Biomedical Science Letters
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• v.8 no.4
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• pp.211-215
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• 2002

The baculovirus/Sf9 cell expression can be employed as a powerful system for producing large amounts of the human erythrocyte glucose transporter, GLUT1 heterologously In order to exploit the system further, it is necessary to develop a convenient method for demonstrating that the transporter expressed in insect cells is biologically active. To achieve this, we have expressed the human CLUT1 in insect cells and photolabelled the expressed protein with [$^3$H] cytochalasin B, a potent inhibitor of the human erythrocyte glucose transporter. Subsequently, the labelled proteins were analysed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Membranes labelled with [$^3$H] cytochalasln B in the presence of L-Glucose yielded a single sharp peak of labelling of apparent $M_r$ 45,000 on SDS/polyacrylamide gels. The mobility of this peak corresponded exactly to that of the band detected by anti-glucose transporter antibodies on Western blots of membranes prepared from insect cells infected with recombinant virus. In addition, the sharpness of the radioactive peak provides further evidence for the conclusion that the expressed protein is much less heavily and heterogeneously glycosylated than its erythrocyte counterpart. No peak of labelling was seen with the membranes prepared from non-infected Sf9 cells. Furthermore, the incorporation of label into this peak was completely inhibited by the presence of 500 mM-D-Glucose during tile photolabelling procedure, showing the stereoselectivity of the labelling. These evidences clearly show that human glucose transporter expressed in insect cells exhibits native-like biological activity, and that photolabelling with [$^3$H] cytochalasin B can be a convenient means for analysing the biological activity of the transport protein expressed in insect cells.

• International Journal of Industrial Entomology and Biomaterials
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• v.23 no.1
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• pp.123-128
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• 2011

1-Deoxynojirimycin (DNJ) is an alkaloid that is found at relatively high concentrations in mulberry leaf and tissues of the silkworm, $Bombyx$ $mori$. DNJ is a well known inhibitor of ${\alpha}$-glucosidase, an enzyme that is involved in the early stages of the $N$-linked glycoprotein synthesis pathway. ${\alpha}$-Glucosidase activity in the cell extract from $B.$ $mori$-derived Bm5 cells showed approximately 40-fold less sensitivity to DNJ than ${\alpha}$-glucosidase activity in the cell extract from $Spodoptera$ $frugiperda$-derived Sf9 cells. The replication of $B.$ $mori$ nucleopolyhedrovirus (BmNPV) was not inhibited when it was propagated in BmN cells that were grown in medium containing up to 10 mM DNJ. In contrast, the replication of $Autographa$ $californica$ multiple NPV (AcMNPV) was reduced by 67% when it was propagated in Sf9 cells that were grown in medium containing 10 mM DNJ. The viability of Bm5 and Sf9 cells that were grown in medium containing up to 10 mM DNJ was not affected. Our results suggested that the reduced replication of AcMNPV was the result of the higher sensitivity of ${\alpha}$-glucosidase activity in Sf9 cells to DNJ.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.4
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• pp.1-8
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• 2014

In order to cope with shadow areas and to extend cell coverage, relay-assisted wireless communication systems have been widely studied. In this paper, we propose a space-frequency(SF) block coded orthogonal frequency division multiple access(OFDMA) transmission system in a relaying multi-path shadow area. The receiving performance of mobile station in a shadow area can be improved by applying SF block code to the recovered signals of multiple relays before re-transmitting them. The simulation result shows that the proposed SF block coded OFDMA transmission system considerably outperforms the conventional single-path OFDMA transmission system.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.1
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• pp.101-104
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• 2003

It has been suggested that oxidative stress of reactive oxygen species(ROS) may play a key role in the pathogenesis of neuronal complications. The aim of this study was to examine the cytotoxic effect of hydrogen peroxide(H₂O₂) in the cultured mouse cerebral neurons and the protective effect of Schisandrae Fructus(SF) on ROS-induced neurotoxicity. Cytotoxic effect of H₂O₂ and neuroprotective effect of SF were determined by MTT assay. H₂O₂ decreased cell viability in dose-and time-dependent mannner, and SF decreased H₂O₂-induced neurotoxicity in these cultures. From above the results, H₂O₂ has toxic effect, and herb extract, SF is very effective against H₂O₂-induced neurotoxicity in cultured cerebral neurons of mouse.