• Korean Journal of Materials Research
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• v.32 no.4
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• pp.186-192
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• 2022

Collagen is one of the most widely used biological materials in medical design. Collagen extracted from marine organisms can be a good biomaterial for tissue engineering applications due to its suitable properties. In this study, collagen is extracted from fish skin of Ctenopharyngodon Idella; then, the freeze drying method is used to design a porous scaffold. The scaffolds are modified with the chemical crosslinker N-(3-Dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride (EDC) to improve some of the overall properties. The extracted collagen samples are evaluated by various analyzes including cytotoxicity test, SDS-PAGE, FTIR, DSC, SEM, biodegradability and cell culture. The results of the SDS-PAGE study demonstrate well the protein patterns of the extracted collagen. The results show that cross-linking of collagen scaffold increases denaturation temperature and degradation time. The results of cytotoxicity show that the modified scaffolds have no toxicity. The cell adhesion study also shows that epithelial cells adhere well to the scaffold. Therefore, this method of chemical modification of collagen scaffold can improve the physical and biological properties. Overall, the modified collagen scaffold can be a promising candidate for tissue engineering applications.

• IMMUNE NETWORK
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• v.16 no.1
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• pp.13-25
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• 2016

Dendritic cells (DCs) are considered to play major roles during the induction of T cell immune responses as well as the maintenance of T cell tolerance. Naive CD4⁺ T cells have been shown to respond with high plasticity to signals inducing their polarization into effector/helper or regulatory T cells. Data obtained from in vitro generated bone-marrow (BM)-derived DCs as well as genetic mouse models revealed an important but not exclusive role of DCs in shaping CD4⁺ T cell responses. Besides the specialization of some conventional DC subsets for the induction of polarized immunity, also the maturation stage, activation of specialized transcription factors and the cytokine production of DCs have major impact on CD4⁺ T cells. Since in vitro generated BM-DCs show a high diversity to shape CD4⁺ T cells and their high similarity to monocyte-derived DCs in vivo, this review reports data mainly on BM-DCs in this process and only touches the roles of transcription factors or of DC subsets, which have been discussed elsewhere. Here, recent findings on 1) the conversion of naive into anergic and further into Foxp3^- regulatory T cells (Treg) by immature DCs, 2) the role of RelB in steady state migratory DCs (ssmDCs) for conversion of naive T cells into Foxp3⁺ Treg, 3) the DC maturation signature for polarized Th2 cell induction and 4) the DC source of IL-12 for Th1 induction are discussed.

• Animal cells and systems
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• v.5 no.4
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• pp.303-308
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• 2001

The skin structure of Misgurnus mizolepis was studied based on the microanatomical investigation of skin fragments taken from four regions. The epidermis was distinguished by two types of skin glands, a small mucous cell and a large club cell. The mucous cell was acid sulfomucins (some sialomucins) but the club cell did not give any histochemical tests for mucosubstances. The presence of a well defined lymphatic system with small lymphocytes was established in the stratum germinativum layer of the epidermis. A large number of blood capillaries run very close to each other just below the basement membrane, and a definite area giving AB and PAS positive was present between the basement membrane and scale. These structural features of skin in M. mizolepis seem to be closely related with cutaneous respiration.

• ETRI Journal
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• v.22 no.4
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• pp.40-50
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• 2000

We apply a "sliding-window" Maximum Likelihood(ML) estimator to estimate traffic parameters On-Off source and develop a method for estimating stochastic predicted individual cell arrival rates. Based on these results, we propose a simple Connection Admission Control(CAC)scheme for delay sensitive services in broadband onboard packet switching satellite systems. The algorithms are motivated by the limited onboard satellite buffer, the large propagation delay, and low computational capabilities inherent in satellite communication systems. We develop an algorithm using the predicted individual cell loss ratio instead of using steady state cell loss ratios. We demonstrate the CAC benefits of this approach over using steady state cell loss ratios as well as predicted total cell loss ratios. We also derive the predictive saturation probability and the predictive cell loss ratio and use them to control the total number of connections. Predictive congestion control mechanisms allow a satellite network to operate in the optimum region of low delay and high throughput. This is different from the traditional reactive congestion control mechanism that allows the network to recover from the congested state. Numerical and simulation results obtained suggest that the proposed predictive scheme is a promising approach for real time CAC.

• BMB Reports
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• v.48 no.12
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• pp.655-667
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• 2015

Lineage tracing is a widely used method for understanding cellular dynamics in multicellular organisms during processes such as development, adult tissue maintenance, injury repair and tumorigenesis. Advances in tracing or tracking methods, from light microscopy-based live cell tracking to fluorescent label-tracing with two-photon microscopy, together with emerging tissue clearing strategies and intravital imaging approaches have enabled scientists to decipher adult stem and progenitor cell properties in various tissues and in a wide variety of biological processes. Although technical advances have enabled time-controlled genetic labeling and simultaneous live imaging, a number of obstacles still need to be overcome. In this review, we aim to provide an in-depth description of the traditional use of lineage tracing as well as current strategies and upcoming new methods of labeling and imaging.

• BMB Reports
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• v.47 no.6
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• pp.354-359
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• 2014

The types of glia in the central nervous system (CNS) of the Drosophila embryo include longitudinal glia (LG), cell body glia (CBG), and peripheral glia (PG). Transcription factors, such as glial cell missing and reverse polarity, are well-established general glial cell markers. Only a few glial cell-specific markers have been identified in the Drosophila embryonic CNS, thus far. In the present study, we employed the glial cell-specific markers for LG (vir-1/CG5453 and CG31235), CBG (fabp/CG6783 and CG11902), and PG (CG2310 and moody/CG4322), and comprehensively analyzed their expression patterns, during the embryonic CNS development. Our study validated the specificity of a set of glial markers, and further revealed their spatio-temporal expression patterns, which will aid in the understanding of the developmental lineage, and investigating their role in the development and homeostasis of the Drosophila CNS in vivo.

• Applied Microscopy
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• v.44 no.2
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• pp.61-67
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• 2014

Layered structures of fiber cell wall of Korean red pine (Pinus densiflora) were investigated by confocal reflection microscopy (CRM). CRM micrographs revealed detailed structures of the fiber cell wall such as S1, S2, and S3 layers as well as transition layers (S12 and S23 layers), which are present between the S1, S2, and S3 layers. Microfibril angle (MFA) measurement was possible for the S2 and S3 layer in the cell wall. The experimental results suggest that CRM is a versatile microscopic method for investigation of layered structures and MFA measurement in individual sub layer of the tracheid cell wall.

• ALGAE
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• v.19 no.2
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• pp.149-151
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• 2004

Freshwater algae make up a very important portion of the autotrophic component of the aquatic food web. Therefore, the study of freshwater algal structure and biomass is central to aquatic ecosystem studies. Due to variations in cell shape and size for each species (or taxon) and survey site, cell abundance (or cell numbers per chosen volume) often leads to misrepresentation of the true importance of some species because of the great differences in size of various algae. Thus, it is necessary to investigate the freshwater algal species of a site in order to calculate the cell volume. Although direct cell counting, species volume measurement, as well as biomass calculation are time-consuming and requiring specialists in taxonomy.

• Journal of Society of Preventive Korean Medicine
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• v.10 no.2
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• pp.19-30
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• 2006

It is well known that glucocorticoid may induce osteoporosis as its side effect in long-term therapy. The inhibition of osteoblast by glucocorticoid is also recognized as its action mechanism of decreased bone formation. In this study, the effect of DSG, Danchisoyosangamibang, on the differentiation and function of osteoblastic cells was investigated. The osteoblastic cells were isolated from rat calvariae using collagenase treatment. The cell counting, enzyme activity assay, MTT assay, collagen content assay were done to determine the cell proliferation, intracellular alkaline phosphatase (ALP) activity, bone martrix production, and cell apoptosis. DSG enhanced the cell proliferation after the culture for 10 days. ALP activity and total protein synthesis, and intracelluar collagen synthesis were increased time dependently when the cells were treated with DSG in the presence of dexamethasone. And, DSG restored calvarial cell function decreased by dexamethasone.

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.1
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• pp.1-9
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• 2005

This paper proposes the heuristic algorithm for the generalized GT problems to consider the restrictions which are given the number of machine cell and maximum number of machines in machine cell as well as minimum number of machines in machine cell. This approach is split into two phase. In the first phase, we use the similarity coefficient which proposes and calculates the similarity values about each pair of all machines and sort these values descending order. If we have a machine pair which has the largest similarity coefficient and adheres strictly to the constraint about birds of a different feather (BODF) in a machine cell, then we assign the machine to the machine cell. In the second phase, we assign parts into machine cell with the smallest number of exceptional elements. The results give a machine-part grouping. The proposed algorithm is compared to the Modified p-median model for machine-part grouping.