• Transactions on Electrical and Electronic Materials
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• v.3 no.1
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• pp.9-13
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• 2002

In this work, the surface of inorganic fillers were modified with some functional groups such as stearic acid, aliphatic long chain, vinylsilane and aminosilane to control the interaction between inorganic fillers and polymer matrix. Ethylene-vinyl acetate copolymers (EVA) with various amount of vinyl-acetate and copolyether-ester elastomer were used as polymer matrix. The addition of inorganic fillers increases flame retardancy, but results in steep drop of electrical and mechanical properties, which may be caused by the defects in the interface between organic/inorganic hybrid composites. The hybrid composites are found to show better mechanical properties and higher volume resistivities as inorganic fillers are well dispersed and have good adhesion with polymer matrix. Also, the most effective type of functional group coated on fillers depends on the chemical structure of polymer.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.74-74
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• 2020

Skin is continuously exposed to a variety of environmental stresses, including ultraviolet (UV) radiation. UVB is an inherent component of sunlight that crosses the epidermis and reaches the upper dermis, leading to increased oxidative stress, activation of inflammatory response and accumulation of DNA damage among other effects. In the present study, the anti-wrinkle mechanism of Acorus gramineus callus culture supernatant (GB-AGS-PSC) was elucidated in UVB treated HaCaT keratinocytes. GB-AGS-PSC prevented the matrix metalloprotease 1 (MMP-1), elastin, and pro-collagen product and cytotoxicity and SOD inhibition. Quantitative polymerase chain reaction showed that GB-AGS-PSC-treated cells displayed dose-dependent increase in messenger RNA expression levels of Aquaporin 3 (AQP3), Keratin 1(KRT1), fillagrin, and hyaluronan synthase-2 (HAS 2) and decreased expression levels of matrix metalloproteinase-3, -9, and -13 in UVB treated HaCaT keratinocytes. Additionally, GB-AGS-PSC suppressed TNF-α, IL-1β, and IL-8 product for inflammatory responses in UVB treated HaCaT keratinocytes. Therefore, GB-AGS-PSC may be useful as an anti-photoaging resource for the skin.

• Communications for Statistical Applications and Methods
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• v.17 no.5
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• pp.639-645
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• 2010

We consider a subdiagonal bilinear model and give sufficient conditions for the associated Markov chain defined by Pham (1985) to be uniformly ergodic and then obtain the $\beta$-mixing property for the given process. To derive the desired properties, we employ the results of generalized random coefficient autoregressive models generated by a matrix-valued polynomial function and vector-valued polynomial function.

• Bulletin of the Korean Mathematical Society
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• v.43 no.2
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• pp.277-292
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• 2006

We consider a single-server queue with service time distribution of phase type where positive customers, negative customers and disasters arrive according to a Markovian arrival process with marked transitions (MMAP). We derive simple formulae for the stationary queue length distributions. The Laplace-Stieltjes transforms (LST's) of the sojourn time distributions under the combinations of removal policies and service disciplines are also obtained by using the absorption time distribution of a Markov chain.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.711-712
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• 2000

DNA probe assay comprising a microwell as' solid matrix for the immobilization of streptavidin (SA) and an oligonucleotide with covalently bound fluorecein as detection probe was developed. The insolubilized SA captured the biotinylated DNA product of polymerase chain reaction (PCR), and the product was denatured under a basic condition. The remaining single-stranded DNA on the solid surface was hybridized with the probe for signal generation that was performed based on enzyme-linked immuno -reactions.

• Journal of the Korean Data and Information Science Society
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• v.14 no.3
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• pp.441-450
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• 2003

Collaborative filtering is one of the most widely used methodologies for recommendation system. Collaborative filtering is based on a data matrix of each customer's preferences and frequently, there exits missing data problem. We introduced two imputation approach (multiple imputation via Markov Chain Monte Carlo method and multiple imputation via bootstrap method) to improve the prediction performance of collaborative filtering and evaluated the performance using EachMovie data.

• Korean Journal of Materials Research
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• v.3 no.3
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• pp.272-275
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• 1993

To modify the toughness of epoxy for matrix, succinonitrile(SN) was introduced to diglycidy1 ether of bisphenol-A (DGEBA)/methylene dianiline(MDA)system. Cure reaction mdchanism of the DGEBA/MDA/SN system was strdied through Fourier transform infrared(FT-IR) spectrometry. As a result, the reaction of nitrile group of SN with secondary amine and with hydroxy1 group prevented the reaction of hydroxy1 group with epoxide group from crossoinding. Nitrile groups produced amide group by reacting with hydroxy1 groups and made a lowered crosslind density in chain networks.

• Archives of Plastic Surgery
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• v.39 no.2
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• pp.106-112
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• 2012

Background : Complicated diabetic patients show impaired, delayed wound healing caused by multiple factors. A study on wound healing showed that platelet-rich plasma (PRP) was effective in normal tissue regeneration. Nonetheless, there is no evidence that when platelet-rich plasma is applied to diabetic wounds, it normalizes the diabetic wound healing process. In this study, we have analyzed matrix metalloproteinase (MMP)-2, MMP-9 expression to investigate the effect of PRP on diabetic wounds. Methods : Twenty-four-week-old male Otsuka Long-Evans Tokushima Fatty rats were provided by the Tokushima Research Institute. At 50 weeks, wounds were arranged in two sites on the lateral paraspinal areas. Each wound was treated with PRP gel and physiologic saline gauze. To determine the expression of MMP-2, MMP-9, which was chosen as a marker of wound healing, reverse transcription polymerase chain reaction (RT-PCR) was performed and local distribution and expression of MMP-2, MMP-9 was also observed throughout the immunohistochemical staining. Results : RT-PCR and the immunohistochemical study showed that the levels of MMP-2, MMP-9 mRNA expression in PRP applied tissues were higher than MMP-2, MMP-9 mRNA expression in saline-applied tissues. MMP-9 mRNA expression in wounds of diabetic rats decreased after healing began to occur. But no statistical differences were detected on the basis of body weight or fasting blood glucose levels. Conclusions : This study could indicate the extracellular matrix-regulating effect observed with PRP. Our results of the acceleration of wound healing events by PRP under hyperglycemic conditions might be a useful clue for future clinical treatment for diabetic wounds.

• Journal of Periodontal and Implant Science
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• v.35 no.1
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• pp.21-30
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• 2005

Matrix metalloproteinases (MMPs) are a family of host-derived proteolytic enzymes and implicated in the remodeling and degradation of extracellular matrix under both physiological and pathological conditions. Connective tissue degradation in periodontal diseases is thought to be due to excessive MMP activities over their specific inhibitors. The effects of lipopolysaccharide (LPS) from Prevotella intermedia, one of the major putative pathogens of periodontitis, on the expression of mRNA for MMPs and tissue inhibitors of metalloproteinases (TIMPs) in human gingival and periodontal ligament fibroblasts were examined by reverse transcriptase-polymerase chain reaction (RT-PCR). The expression of mRNAs encoding MMP-1, -2, -3, -10, and -14 was increased in human gingival fibroblasts treated with p. intermedia LPS, whereas MMP-11 and TIMP-2 mRNA expression was decreased in these cells stimulated with LPS. P. intermedia LPS increased the MMP-1, -2, -10, -11, and -14 mRNA expression and decreased TIMP-1 and -2 mRNA expression in human periodontal ligament fibroblasts. These findings imply that P. intermedia LPS may play an important role in the connective tissue degradation in periodontitis.

• Korean Journal of Microbiology
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• v.30 no.5
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• pp.339-346
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• 1992

These studies were carried out to identify Bacillus cereus group 1..5-] strain isolated from 5uyeong Bay. This strain was differentiated from B. cereus group using conventional, API system and fatty acid composition analysis. Colony characteristics were opague. mucoid, entire margin. convex. circular and non hemolysis on sheep blood agar plates, and were observed with central spore forming positive bacilli in a Gram stained preparation. and had no motility. The carbohydrates tested; glucose.maltose, and sucrose were assimilated but neither trehalose nor salicin were assimilated. This strain ultilized gelatin and was also inhibited by 6.5% NaCI. The results of biochemical examination were differented from B. cereus group LS-1 compared with others B. cereus group. The fatty acid composition contained major amounts of branched chain acids. iso $C_{15}$ and iso $C_{13}$ and the range of chain length was $C_{12}$ to C"$C_{17}$ and n$C_{15}$, acid was not detected. Automated fatty acid computer profile indicated "B. mycoides GC subgroup B of 0.312 similarity index." The results agreed with other research cases. On the other hand. A TB computer prolile index of API system (API 50 CHB & API 20E) identified" Doubtful profile of 99.7% B. firmus" . These results were presented with considerable discrepancies between API system and fatty acid analysis. With 67 biochemical characters. the similarity matrix of B. mycaides (KCTC 1033). B. thuringiensis (KCTC 1033). B. cereus (5-3) and B. mycoides (S-12) showed 42%. 42%. 59%, and 52%. respectively. Through the key tests and fatty acid analyses. we could notice the appearance of B. mycoides of the B. cereus group and this leads us to suspect the existence of a new biotype B. mycoides.