• Journal of Magnetics
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• v.21 no.1
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• pp.125-132
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• 2016

High gradient magnetic separation (HGMS) is the most commonly used magnetic cell separation technique in biomedical science. However, parameters determining target cell capture efficiencies in HGMS are still not well understood. This limitation leads to loss of information and resources. The present study develops a bead-capture theory to predict capture efficiencies in HGMS. The theory is tested with CD3- and CD14-positive cells in combination with paramagnetic beads of different sizes and a generic immunomagnetic separation system. Data depict a linear relationship between normalized capture efficiency and the bead concentration. In addition, it is shown that key biological functions of target cells are not affected for all bead sizes and concentrations used. In summary, linear bead-capture theory predicts capture efficiency ($E_t$) in a highly significant manner.

• Journal of the Korean Society of Tobacco Science
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• v.25 no.2
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• pp.128-136
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• 2003

Although tobacco smoke has been known to have genotoxicity as well as cytotoxicity, the sensitivity of the cell lines used against cigarette smoke is poorly understood. The objective of this study was to evaluate and compare the genotoxicity of several cell lines, which are routinely used in the in vitro assays, with cigarette smoke condensate(CSC) of Kentucky Reference Cigarette 1R4F. In the micronucleus(MN) induction assays, murine(CHO-K1, V79, BALB/c 3T3) cell lines and human(MCF-7, A549) ones were used. As a result, the CSC exhibited cytotoxicity with a concentration-dependent response in all cell lines. EC$_{50}$ of CSC in CHO-K1, V79, BALB/c 3T3, MCF-7 and A549 were 140, 125, 100, 116 and 109 $\mu\textrm{g}$/mL, respectively. On the other hand, the spontaneous micronucleated cell(MNC) frequency was stable and reproducible in every cell lines tested in this study. The dose-response of various cell lines to the induction of MN by CSC was estimated using linear regression analysis. CSC(0～100 $\mu\textrm{g}$/mL) caused a dose-dependent MN induction in CHO-K1, V79, BALB/c 3T3 and MCF-7 cell lines. Putting together all the data obtained and linear regression analysis of the data, we concluded that V79 cells are more susceptible to the accurate assessment of CSC-induced MN than the others.s.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1722-1724
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• 2005

The focus of this paper is to develop a mathematical model for investigating the dynamic performance of a polymer electrolyte membrane fuel cell. The model in this work is based on physical laws having clear significance in replicating the fuel cell system and can easily be used to set up different operational strategies. Simulation results display the transient behavior of the voltage within each single cell, and also within a number of such single cells combined into a fuel cell stack system. A linear as well as a nonlinear analysis of the polymer electrolyte membrane fuel cell system(PEMFC) has been discussed in order to present a complete and comprehensive view of this kind of modeling. Also, a comparison of the two kinds of analysis has been performed. Finally, the various characteristics of the fuel cell system are plotted in order to help us understand its dynamic behavior. Results indicate that there is a considerable amount of error in the modeling process if we use a linear model of the fuel cell. Thus, the nonlinearities present in the fuel cell system should be taken into account in order to obtain a better understanding of the dynamic behavior of the fuel cell system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.6
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• pp.539-545
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• 2014

Contact resistivity between silver electrodes and the emitter layer of a silicon solar cell wafer has been measured using either the circular transmission line method or the linear transmission line method. The circular transmission line method has an advantage over the linear transmission line method, in that it does not require an additional process for mesa etching to eliminate the leakage current. In contrast, the linear transmission line method has the advantage that its specimen can be acquired directly from a silicon solar cell. In this study, measured resistance data for the calculation of contact resistivity is compared for these two methods, and the mechanism by which the linear transmission line method can more realistically reflect the impact of the width and thickness of a silver electrode on contact resistivity is investigated.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3053-3059
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• 2012

Human epidermal growth factor receptor 2 (HER2) is a member of the epidermal growth factor receptor family of receptor tyrosine kinases that plays important roles in all processes of cell development. Their overexpression is related to many cancers, including examples in the breast, ovaries and stomach. Anticancer therapies targeting the HER2 receptor have shown promise, and monoclonal antibodies against subdomains II and IV of the HER2 extra-cellular domain (ECD), Pertuzumab and Herceptin, are currently used in treatments for some types of breast cancers. Since anti HER2 antibodies targeting distinct epitopes have different biological effects on cancer cells; in this research linear and conformational B cell epitopes of HER2 ECD, subdomain III, were identified by bioinformatics analyses using a combination of linear B cell epitope prediction web servers such as ABCpred, BCPREDs, Bepired, Bcepred and Elliprro. Then, Discotope, CBtope and SUPERFICIAL software tools were employed for conformational B cell epitope prediction. In contrast to previously reported epitopes of HER2 ECD we predicted conformational B cell epitopes $P1_C$: 378-393 (PESFDGDPASNTAPLQ) and $P2_C$: 500-510 (PEDECVGEGLA) by the integrated strategy and P4: PESFDGD-X-TAPLQ; P5: PESFDGDP X TAPLQ; P6: ESFDGDP X NTAPLQP; P7: PESFDGDP-X-NTAPLQ; P8: ESFDG-XX-TAPLQPEQL and P9: ESFDGDP-X-NTAPLQP by SUPERFICIAL software. These epitopes could be further used as peptide antigens to actively immune mice for development of new monoclonal antibodies and peptide cancer vaccines that target different epitopes or structural domains of HER2 ECD.

• 한국전산유체공학회:학술대회논문집
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• 2003.08a
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• pp.31-36
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• 2003

A field reconstruction scheme for a cell centered finite volume method on unstructured meshes is developed. Regardless of mesh quality, this method is exact within a machine accuracy if the solution is linear, which means it has full second order accuracy. It does not have any limitation on cell shape except convexity of the cells and recovers standard discretization stencils at structured orthogonal grids. Accuracy comparisons with other popular reconstruction schemes are performed on a simple example.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.3
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• pp.171-177
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• 2002

The metabolic flux pattern for L-histidine production was analyzed when glucose and/or acetate were used as carbon sources. Total L-histidine production was enhanced when mixed substrate (glucose and acetate) was used, compared wish that when either glucose or acetate was used as the sole carbon source. Theoretical maximum carbon fluxes through the main pathways for L-histldine production, cell growth, and ATP consumption for cell maintenance were obtained by the linear programming (LP) method. By comparison of the theoretical maximum carbon fluxes tilth actual ones, it was found that a large amount of glucose was actually used for maintenance of cell viability. On the other hand, acetate was used for cell growth. After depletion of acetate in the mixed substrate culture, the flux for glucose to L-histldine synthesis was markedly enhanced. A strategy for effective L-histidine production using both carbon sources was proposed.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.175-178
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• 2014

The flame cell dynamics in 2-D opposed nonpremixed tubular configuration was investigated using high-fidelity numerical simulations. The diffusive-thermal instability occurs as the $Damk{\ddot{o}}hler$ number, Da, approaches the 1-D extinction limit of the tubular flames and several flame cells are generated depending on Da, and flame radius. In general, the number of flame cells are found close to the largest wave number from the linear stability analysis. It was also found from the displacement speed analysis that during the local flame extinction and cell formation, negative edge flame speed is observed due to small gain from reaction compared to large loss from diffusion.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.4
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• pp.557-564
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• 1986

This paper describes a standard cell placement strategy which consists of three kconsecutive steps` initial placement, iterative placement improvement, and string placement. In the initial placement step, cell placement was done by solving the linear ordering problem for a one-dimensional layout of standard cells and then zigzaging the resultant linear order width in the chip plane. The iterative placement improvement step is based on the iterative pairwise interchange using the estimated total routing length as a figure-or -merit. The string placement is used to reorder cells and terminals in each etandard cell row such that channel routing in the adjacent channels is not blocked by cyclic constraints and needs fewer routing tracks. The placement program is coded in PASCAL and kimplemented on a VAX-11/750 computer. Experimental results for several examples are included.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.212-217
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• 2007

As a preliminary study for the development of electrical stimulation strategy of artificial retina, we set up a method fur the reconstruction of input intensity variation from retinal ganglion cell(RGC) responses. In order to estimate light intensity variation, we used an optimal linear filter trained from given stimulus intensity variation and multiple single unit spike trains from RGCs. By applying ON/OFF stimulation(ON duration: 2 sec, OFF duration: 5 sec) repetitively, we identified three functional types of ganglion cells according to when they respond to the ON/OFF stimulus actively: ON cell, OFF cell, and ON-OFF cell. Experiments were also performed using a Gaussian random stimulus and a binary random stimulus. The input intensity was updated once every 90 msec(i. e. 11 Hz) to present the stimulus. The result of reconstructing 11 Hz Gaussian and binary random stimulus was not satisfactory and showed low correlation between the original and reconstructed stimulus. In the case of ON/OFF stimulus in which temporal variation is slow, successful reconstruction was achieved and the correlation coefficient was as high as 0.8.