• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2013.11a
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• pp.221-222
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• 2013

다양한 첨가제가 들어가는 고분자 화합물(compound)의 제조에 있어 난연 발포 보조제인 팽창흑연(Expandable Graphite, EGP)은 흡유가가 낮기 때문에 비교적 많은 양을 첨가해도 혼합(Mixing)이 잘 되는 것으로 알려져 있다. 본 논문에서는 대표적인 인계 난연제 APP(Ammonium Polyphosphate)를 사용한 난연 EPDM(Ethylene Propylene Diene Monomer) 폼에 팽창흑연 첨가량을 증가시키면서 산소 지수와 발열량을 통해 난연 성능의 변화를 분석하였다. 산소지수는 ISO 4589-2 상온 산소지수 방법을, 발열량 평가는 ISO 5660-1 콘 칼로리미터를 활용하였다.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.77-80
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• 2000

Various analytical methods such as electron microscopy, quinone analysis, and 16S rDNA sequencing studies were used to investigate the microbial communities and to identify the microorganisms responsible for enhanced biological phosphorus removal (EBPR) in an anaerobic/aerobic sequencing batch reactor (SBR) fed with acetate. Electron photomicrographs showed that oval-shaped microorganisms of about $0.7\;{\sim}\;1\;{\mu}m$ in diameter dominated the microbial sludge. These microorganisms contained polyphosphate granules and glycogen inclusions, which suggests that they are a kind of phosphorus accumulating organism. Quinone and 16S rRNA sequence analyses showed that the members of Proteobacteria beta subclass were the most abundant species, which were affiliated with the Rhodocyclus-likes group. Phylogenetic analysis revealed that the two dominating clones of the beta subclass were most distantly related to Propionivibrio dicarboxylicus DSM 5885 and Rhodocyclus tenuis DSM 109 with about 95% and 96% sequence similarity, respectively. Therefore, it was concluded that the oval-shaped organisms related to the Rhodocyclus-likes group are likely to be responsible for biological phosphorus removal in SBR operation supplied with acetate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.11
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• pp.1205-1211
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• 2004

This study has investigated radiation degradation of chloroprene rubber in the presence of some fire retardant. Ammonium polyphosphate, aluminium trihydroxide, magnesium hydroxide, calcium carbonate and antimony trioxide were selected as flame retardant. Samples were irradiated using a Co$^{60}$ ${\gamma}$ -ray and ray up to 2000 kGy at a dose rate of 5 kGy/hr in the presence of air atmosphere at room temperature. After irradiation, samples were assessed fire retardancy with electrical properties and mechanical properties. Some considerations concerning the effects of the fire retardants added to chloroprene rubber on the radiation and thermal stability of chloroprene rubber are presented. From fire retardancy with electrical and mechanical property measurements, it was found that addition of magnesium hydroxide resulted in maximum fire retardant effect.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.2
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• pp.228-237
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• 2005

The main purpose of this study was to investigate the red water reducing effects of phosphate based inhibitor when it was applied to water distribution system. The effects of pH, alkalinity, calcium concentration in the reduction of the red water also studied. The most finished water in Korea showed relatively high corrosiveness and was required to introduce some types of corrosion reducing methods such as addition of alkalinity. The precipitation of $CaCO_3$ by addition of $Ca(OH)_2$ formed porous film on the surface of the carbon steel pipes and was displaced easily from the surface of the pipes; on the other hand, addition of zinc phosphate (ZOP) formed reliable film on the surface and reduced iron release and color. Although the main function of ZOP was to suppress the release of Pb and Cu, it also reduced iron concentration released from water distribution pipes.

• Journal of Periodontal and Implant Science
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• v.30 no.2
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• pp.213-231
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• 2000

이 연구의 목적은 다공성의 CPP 내부에 쥐의 장골의 골수에서 유래된 세포를 접종하고 3차 원적으로 배양하여 CPP가 골 형성을 위한 조직공학의 지지체로 적용가능한가를 연구하는 것과 Calcium PolyPhosphate(CPP)의 돌연변이 유발성을 검사하는 것이다. 무수 ($Ca(H_2PO_4)$)를 condensation하여 무결정의 ($Ca(PO_3)$)를 얻고 이를 용융하고 냉각시킨 후 분쇄하여 Calcium polyphosphate(CPP) powder를 얻었다. 다공성의 CPP는 5% $SiO_2$를 첨가하여 sponge 형태로 $450-550{\mu}m$ 소공의 크기를 가지는 것과(CPP-45ppi) $200-300{\mu}m$의 소공의 크기를 가지는 것(CCP-60ppi) 2가지로 제작하였다. 각각의 CPP matrices는 $5mm{\times}5mm{\times}1mm$의 블록 형태로 만들었다. 체중 100g 내외의 백서에서 장골(femur, tibia)을 채취하여 백서의 장골 골수 세포를 분리하여 배양한 후 24well에 CPP block을 넣고 CPP block 당 $10^5$개의 배양한 세포를 접종하였다. 배양 1, 7, 14, 및 21 일째에 각 well에서 trypsin EDTA를 이용하여 2회 반복하여 cell을 분리하였고, 원심분리한 후 hemacytometer로 측정하였다. 또, 45ppi와 60ppi, 그 리 고 Tissue Culture Polystyrene(control group)에 접종, 배양된 세포들의 염기성 인산분해효소활성도를 배양 7, 14, 및 21 일째에 각각 측정하였다. 각 기간별로 배양된 세포-CPP 혼합체내에서 세포의 부착 및 증식과 형성된 조직의 3차원적 형태를 관찰하기 위하여 주사전자현미경하에서의 관찰하였다. CPP의 돌연변이 유발성 검사 (mutagenicity test)를 위해 hypoxanthine-guanine phosphoribosyl transferase(HPRT) assay를 하였다. NIH3T3 cell line과 CHO-K1 cell line으로 각각 $1000{\mu}g/m{\ell}$, $100{\mu}g/m{\ell}$, $10{\mu}g/m{\ell}$ 그리고 $1{\mu}g/m{\ell}$의 CPP 농도에서 측정하였다. 통계적 분석을 위해서 모든 측정은 각군당 4개체 이상 시험하였고, 각 측정값은 평균값${\pm}$표준편차로 나타내었다. 각 군간의 통계적 유의성 검정을 위해서 Analysis of variance(ANOVA)를 이용하였고 Tukey의 방법으로 사후분석을 실시하였다. 제작된 CPP matrices 소공들이 서로간에 연결이 잘 되어있는 형태였다. 두 가지로 제조된 CPP(45ppi와 60ppi) 모두에서 세포의 부착이 잘 일어났고, 부착된 세포의 분열도 잘 일어났다. 2 가지의 CPP 모두에서 7, 14, 21일째의 세포 수는 1일째에 비해 유의성 있게 증가하였다(P<0.01). 3차원적 구조인 Calcium PolyPhosphate에서 배양한 세포는 24well dish(tissue culture polystyrene)에서 평면적으로 배양한 대조군의 세포에서 보다 염기성 인산분해효소 (Alkaline Phosphatase)를 유의성 있게 높게 나타냈다. 주사전자현미경에서 세포-CPP 혼합체를 관찰한 결과, CPP block에 세포들이 잘부착되어 있었고, 시간이 지남에 따라 세포가 여러 층을 형성하면서 뭉치는 현상을 보였다. 또, HPRT assay 결과 , Calcium PolyPhosphate는 돌연변이 유발성을 보이지 않았다. 이상의 결과로 볼 때 CPP에는 세포부착이 잘 일어나고, 지지체 상에서 세포의 분열도 활발하게 일어나므로 골조직을 위한 조직공학의 우수한 지지체가 될 수 있을 것으로 사료된다.

• Journal of Life Science
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• v.28 no.3
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• pp.331-338
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• 2018

Melanin is a polymer substance that plays an important role in the determination of hair growth and skin color in vivo. However, melanin, which is over-produced by reactive oxygen species, is known to cause stains, freckles, and hypercholesterolemia, which are associated with aging. Previous studies have shown that polyphosphate, one of the components of Rhynchosia Nulubilis, inhibits skin aging induced by ultraviolet rays. The aim of this study is to investigate the direct effect of Rhynchosia Nulubilis ethanolic extract (RNEE) on melanin synthesis. In this study, RNEE showed no antioxidative effects on scavenging activity of DPPH radical in addition to reducing power. The cytotoxicity of RNEE was increased in a dose-dependent manner in an MTT assay. In addition, RNEE increased tyrosinase activity and melanin synthesis in DOPA-oxidation experiments. RNEE did not promote the conversion L-DOPA into melanin in live cells, but melanin production was promoted in the RNEE-treated group after H2O2 pretreatment compared to the control group in which melanin production was reduced by treatment with H2O2. In addition, RNEE increased the expression level of tyrosinase related protein-2 (TRP-2) and increased the expression level of tyrosinase related protein-1 (TRP-1) at a concentration of $16{\mu}g/ml$. In particular, it was found that RNEE increased the expression level of SOD-3, by which superoxide anion is converted to hydrogen peroxide, higher than the control and ${\alpha}$-MSH used as a positive control at a concentration of more than $16{\mu}g/ml$. The results suggest that RNEE can induce melanogenesis related to black hair.

• Korean Journal of Environmental Agriculture
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• v.11 no.1
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• pp.67-76
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• 1992

A mechanistic study by which Cadmium-tolerant P.Putida C1 accumulates high conc of Cd in its cell body was performed. Approximately 57% Cd accumulated was distributed on the cell wall and the other 43% portion was in cytoplasm. 84% Cd of the Cd in the cell wall fractions present in the polyphosphate-polysaccharide fractions, but most of Cd in the cytoplasm fraction was in protein and nucleic acid. Cadmium affected the protein synthesis in P. Putida. The intracellular protein content was decreased by cadmium addition, but the soluble protein precipitated by ammonium sulfate($30{\sim}75%$ satruation) was increased as compared to that from the cells grwon without cadmium. Furthermore, in the cells grown with of cadmium, high-molecular-weight soluble protein was increased, with of cadmium, high-molecular-weight soluble protein was increased, compared with the cells grown without cadmium, but low-molecular-weight soluble protein was decreased. These results indicate that Cd inhibited the intracellular protein biosynthesis but enhance biosynthesis of the high-molecular-weight soluble protein precipitate by ammonium sulfate($30{\sim}75%$ saturation).

• Microbiology and Biotechnology Letters
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• v.34 no.1
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• pp.40-46
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• 2006

A bacterial strain producing high level of a phytase was isolated from cattle feces and identified as Bacillus subtilis, and designated as Bacillus sp. CF 5-26. The production of the phytase from Bacillus sp. CF 5-26 reached the highest level after 72 hours at $37^{\circ}C$. The optimum condition of the media for the production of phytase was 10% rice bran extract, 0.1% whey protein powder, $0.01%\;CaCl_{2},\;0.01%\;KH_{2}PO_4$. The phytase was purified 20.3 folds with ethanol precipitation, Sephadex G-100, CM Sepharose CL-6B and Sephacryl S-100-HR column chromatography. The molecular weight of the purified enzyme was estimated to be 66 kDa on SDS-polyacrylamide gel electrophoresis. The purified phytase activity was stable up pH 5.0, 7.0, 11.0 and the remaining activity was 50% when it was treated at $100^{\circ}C$ for 1 hour. The substrate specificity of phytase was most active against sodium phytate and inositol polyphosphate compound. And the phytase hydrolysed tripolyphosphate and pyrophosphate a little. The Km value for the sodium phytate was 0.64 mM and the Vmax value was $4.41\;{\mu}mol/min$.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.80-91
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• 2003

Mutans streptococci, especially S. mutans and S. sobrinus strongly implicated in pathogenesis of dental caries, the major cause of tooth loss in children. Use of an antibacterial agent controlling dental caries has been rationalized. The present study was performed to observe the antibacterial effect of inorganic polyphosphates (polyP) on S. mutans and S. sobrinus. S. mutans GS5 and S. sobrinus 6715 were grown in brain-heart infusion broth with or without polyP. Minimal inhibitory concentration (MIC) of polyP for S. mutans GS5 was determined to be 0.08% and that for S. sobrius 6715 was 0.17%. PolyP 15 added to the growing culture of S. mutans GS5 and S. sobrinus 6715 at their exponential phase was as effective in inhibiting the growth of S. mutans GS5 and S. sobrinus 6715 as polyP added at the very beginning of the culture. More than 85% of the cells lost their viability determined by viable cell count when polyP 15 was added to the culture of growing S. mutans GS5 at MIC, suggesting that polyP 15 has bacterial effect on the bacterium. And more than 99.9% of the cells lost their viability determined by viable cell count when polyP 15 was added to the culture of growing S. sobrinus 6715 at MIC, suggesting that polyP 15 has bacterial effect on the bacterium. Intracellular nucleotide release from S. mutans CS5 and S. sobrinus 6715 was increased in the presence of polyP 15 for 5h but was not really reversed by the addition of divalent cations like $Ca^{++}\;and\;Mg^{++}$. The majority of the cells appeared to be atypical in their shape, demonstrating accumulation of highly electron-dense granules and ghost cells. The overall results suggest that polyP have a strong bactericidal activity against S. mutans and S. sobrinus in which lysis in relation to chelation may not play the major role but unknown mechanism that possibly affects the viability of the bacterium may be involved. PolyP may be used as an agent for prevention of dental caries.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.6
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• pp.524-528
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• 2000

Effect of food additives on the heat sensitivity of listeria monocytogenes H-12 inoculated into Pollack surimi was investigated and also confirmed the effectiveness of various decontamination method such as tap water washing, chlorination, ultraviolet irradiation and heat treatment haying been applied on cooking utensils. Food additives such as polyphosphate, chitosan, and potassium sorbate increased heat sensitivity of t monocytogenes H-12 and polyphosphate showed the strongest synergistic effect. The tested strain was not detected from stainless steel and plastic cutting board contaminated with $10^4{\~}10^5/cm^2$ of L monocytogenes H-12 after tap water washing for 10 seconds or 1 minute, but washing effect was not found in wooden cutting board. The chlorination of stainless steel and plastic cutting board for 10 seconds with $5{\~}50 ppm$ solution eliminated all cells of the contaminated strain, however any change of the viable cell count was not observed in the chlorination of wooden cutting board, W irradiation on stainless steel and plastic cutting board for 5 minutes with 15 W above 30 cm eliminated the contaminated strain, but the tested strain was still found after 60 seconds of irradiation on wooden cutting board. The treatment of hot water on all used cutting boards for 10 seconds at $70^{\circ}C$ resulted in complete loss of viability of the contaminated strain.