• Journal of the Korean Mathematical Society
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• v.47 no.1
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• pp.71-81
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• 2010

We characterize linear operators that preserve sets of matrix ordered pairs which satisfy extreme cases with respect to maximal column rank inequalities of matrix multiplications over semirings.

• Journal of applied mathematics & informatics
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• v.11 no.1_2
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• pp.401-412
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• 2003

Using the idea of "intuitionistic fuzzy set" [l, 2, 3], we defined the concept of intuitionistic fuzzy matrices as a natural generalization of fuzzy matrices. And we introduced and studied the determinant of square intuitionistic fuzzy matrices [4]. In this paper, we investigate the adjoint of square intuitionistic fuzzy matrices.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.2
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• pp.17-25
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• 2004

In this Paper, new data matrix structure and respective processing algorithm for digital holographic storage are Proposed. Data matrix consists of user data and reference grid which is used to compensate geometrical errors such as magnification, shift and rotation of stored information. Processing algorithm identifies the location of reference grid and extracts user data. As a result of experiment, raw BER in case of shit, rotation and magnification are 3.09${\times}$10$^{-18}$ , 6.14${\times}$10$^{-12}$ , 1.2${\times}$10$^{-7}$ , respectively.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.203-209
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• 2016

Purpose: Stimulating the proliferation and migration of periodontal ligament cells (PDLCs) has become the main goal of periodontal regeneration. To accomplish this goal, regeneration procedures have been developed, but results have not been predictable. Recently, tissue engineering using enamel matrix derivatives (EMDs) and growth factors has been applied to periodontal regeneration; however, the mechanism of EMDs is largely unknown. The aim of this study was to investigate the effects of EMDs on the proliferation and release of growth factors from PDLCs. Materials and methods: Human PDLCs were removed from individually extracted 3rd molars of healthy young adults, and cultured in the media containing EMDs (Emdogain, Biora, Malmo, Sweden) at concentration of 0, 12.5, 25, 50, 100, and $200{\mu}g/mL$ each. Cell proliferation and ALP (alkaline phosphatase) activity were measured. The evaluation of growth factors released by PDLCs was also performed by one-way analysis of variance (ANOVA) and Bonferroni's multiple comparison test. Results: Significantly increased proliferation and ALP activity were observed in PDLCs treated with over $25{\mu}g/mL$ and $50{\mu}g/mL$ EMDs, respectively. Additionally, treatment of PDLCs with $50{\mu}g/mL$ resulted in significantly increased release of vascular endothelial growth factor (VEGF) and transforming growth factor $(TGF)-{\beta}$ after 24 h and 48 h, respectively. Conclusion: EMDs enhance the proliferation and ALP activity of PDLCs, and promote the release of growth factors, including VEGF and $TGF-{\beta}$, from PDLCs. Therefore EMDs could be one of the effective methods for periodontal regeneration.

• The Journal of Advanced Prosthodontics
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• v.6 no.5
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• pp.406-414
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• 2014

PURPOSE. The objective of this study was to investigate the biologic effects of enamel matrix derivative (EMD) with different concentrations on cell viability and the genetic expression of human gingival fibroblasts (HGF) to zirconia surfaces. MATERIALS AND METHODS. Immortalized human gingival fibroblasts (HGF) were cultured (1) without EMD, (2) with EMD $25{\mu}g/mL$, and (3) with EMD $100{\mu}g/mL$ on zirconia discs. MTT assay was performed to evaluate the cell proliferation activity and SEM was carried out to examine the cellular morphology and attachment. The mRNA expression of collagen type I, osteopontin, fibronectin, and TGF-${\beta}1$ was evaluated with the real-time polymerase chain reaction (RT-PCR). RESULTS. From MTT assay, HGF showed more proliferation in EMD $25{\mu}g/mL$ group than control and EMD $100{\mu}g/mL$ group (P<.05). HGFs showed more flattened cellular morphology on the experimental groups than on the control group after 4h culture and more cellular attachments were observed on EMD $25{\mu}g/mL$ group and EMD $100{\mu}g/mL$ group after 24h culture. After 48h of culture, cellular attachment was similar in all groups. The mRNA expression of type I collagen increased in a concentration dependent manner. The genetic expression of osteopontin, fibronectin, and TGF-${\beta}1$ was increased at EMD $100{\mu}g/mL$. However, the mRNA expression of proteins associated with cellular attachment was decreased at EMD $25{\mu}g/mL$. CONCLUSION. Through this short term culture of HGF on zirconium discs, we conclude that EMD affects the proliferation, attachment, and cell morphology of HGF cells. Also, EMD stimulates production of extracellular matrix collagen, osteopontin, and TGF-${\beta}1$ in high concentration levels. CLINICAL RELEVANCE. With the use of EMD, protective barrier between attached gingiva and transmucosal zirconia abutment may be enhanced leading to final esthetic results with implants.

• Journal of the Korean Chemical Society
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• v.40 no.2
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• pp.109-116
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• 1996

A matrix modification was studied for the determination of trace germanium in mineral waters by electrothermal atomic absorption spectrophotometry (ET-AAS). For this, the type and quantity of modifier as well as the use of auxiliary modifier were investigated to realize the efficient modification. Germanium suffers from low sensitivity and poor reproducibility in ET-AAS determination because of the premature loss of germanium via volatile germanium monoxide formation when heated in the presence of carbon. Therefore, the addition of a matrix modifier is necessary to stablize the germanium, thermally and chemically. By the addition of palladium (10 ${\mu}g/mL)$ as a single modifier to the sample containing 500 ng/mL germanium, the charring temperature could be raised from 800 to $1000^{\circ}C$, and its absorbance was also increased, but the atomization temperature was not raised. In this case, the absorbance of germanium was not changed in the range of 10∼70 ${\mu}g/mL$ of palladium added. On the other hand, it was considered that the use of a mixed modifier could modifiy the matrix more effectively than with a single modifier. The best results were obtained by using 1% ammonium hydroxide as an auxiliary modifier together with 10 ${\mu}g/mL$ palladium. The charring temperature could be raised from 800 to $1100^{\circ}C$, without any change of the atomization temperature. With above optimum conditions, the trace amount of germanium in several mineral waters were determined by a calibration curve method, and good recoveries of more than 95% were also obtained in the samples in which a given amount of germanium was spiked. The detection limit of this method was about 6.9 ng/mL.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.2
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• pp.129-136
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• 2010

In order to evaluate anti-wrinkle activity of Carex humilis extract, free radical scavenging activity, elastase inhibitory activity and reduction of expression Matrix metalloproteinase-1 (MMP-1) mRNA and MMP-1 protein were investigated. The roots of Carex humilis were extracted with 95 % ethanol and successively partitioned with organic solvents with increasing polarity of the solvents. Each fraction of organic solvent were investigated by using free radical scavenging activity and elastase inhibitory activity test. Among them, EtOAc fraction showed antioxidant activity ($SC_{50}$=4.89 ${\mu}g/mL$) and elastase inhibitory activity ($IC_{50}$=23.5 ${\mu}g/mL$). EtOAc fraction was developed on silica gel by open-column chromatography and consecutively re-developed on C18 resin by prep-HPLC to give ${\alpha}$-viniferin as a major component, which was confirmed by spectrometric analysis. In the assay on expression of MMP-1 mRNA by RT-PCR and protein by western-blot, EtOAc layer (10 ~ 100 ${\mu}g/mL$) was reduced about 50 ~ 60 %, 50 ~ 65 % respectively and ${\alpha}$-viniferin (0.5 ~ 2 ${\mu}g/mL$) was inhibited about 60 ~ 75 %, 55 ~ 65 % respectively in human fibroblast. Therefore, our findings suggest that EtOAc layer of Carex humilis containing ${\alpha}$-viniferin can be useful as an active ingredient for cosmeceuticals of anti-wrinkle effects.

• Journal of Microbiology and Biotechnology
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• v.20 no.7
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• pp.1086-1091
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• 2010

This study explored the use of gellan gum as an immobilization matrix for the production of cyclosporin A (CyA) by immobilized spores and mycelia of Tolypocladium inflatum MTCC 557. Different carriers, such as gellan gum, sodium alginate, celite beads, and silica, were tested as immobilization carriers, along with the role of the carrier concentration, biomass weight, number of spore-inoculated beads, and repeated utilization of the immobilized fungus. The maximum CyA production was 274 mg/l when using gellan gum [1% (w/v)], and a mycelial weight of 7.5% (w/v) supported the maximum production of CyA. Additionally, the addition of a combination of $_L$-valine (6 g/l) and $_L$-leucine (5 g/l) after 48 h of fermentation produced 1,338 mg/l of CyA when using gellan gum. The immobilized mycelia beads were found to remain stable for four repetitive cycles, indicating their potential for semicontinuous CyA production.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.1 s.49
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• pp.103-109
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• 2005

UV irradiation leads to distinct changes in skin connective tissue, which is degradation of collagen. Many of these alterations in the extracellular matrix are mediated by matrix metalloproteinases. In this study, to develop a new anti-aging agent, we screened the antioxidant activity of solvent fractions from ethanolic extract of Melothria Heterophylla. Among the four solvent fractions tested, the EtOAc fraction exhibited the highest antioxidant activity. It was investigated the inhibitory effect of the EtOAc fraction on the expression and activity of MMP-1 in UVA-irradiated human dermal fibroblasts. The EtOAc fraction inhibited the activity of MMP-1 in a dose dependent manner with the $IC_{50}$ values of $9{\mu}g/mL$. Also, UVA-induced MMP-1 expression was reduced about $90\%$ by $100{\mu}g/mL$ of the EtOAc fraction but MMP-1 mRNA expression was not inhibited. Therefore, we conclude that the EtOAc fraction significantly inhibits MMP-1 expression at the protein level. From these results, we suggest that the EtOAc fraction from M. heterophylla could be used as a new anti-aging agent for the photo-damaged skin.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.915-920
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• 2007

A new optimal state feedback and disturbance feedforward control design in the sense of minimizing $L_{2}-gain$ from disturbance to control output is proposed for disturbance attenuation of systems with bounded control input and measurable disturbance. The controller is derived in the framework of linear matrix inequality(LMI) optimization. A gain scheduled state feedback and disturbance feedforward control design is also suggested to improve disturbance attenuation performance. The control gains are scheduled according to the proximity to the origin of the state of the plant and the magnitude of disturbance. This procedure yields a stable linear time varying control structure that allows higher gain and hence higher performance controller as the state and the disturbance move closer to the origin. The main results give sufficient conditions for the satisfaction of a parameter-dependent performance measure, without violating the bounded control input condition.