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수산화칼슘 처리된 Porphyromonas endodontalis Lipopolysaccharide가 다형핵백혈구의 IL-1과 TNF-α 생성에 미치는 영향에 관한 연구
박찬제,박동성,유현미,오태석,임성삼 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.5
Bacterial lipopolysaccharide (LPS) plays a major role in stimulating the synthesis and release of the principal osteoclast-activating cytokines , namely, interleukin 1 and tumor necrosis factor-α from immune cells, Although monocytes/macrophages are the main producers of these cytokines, recent evidence has indicated that polymorphonuclear leukocytes (PMN) have the ability to release IL-1 and TNF-α. Calcium hydroxide has been shown to be an effective medicament in root canal infectionsm, reducing the microbial titre within the canal. It has been proposed that the therapeutic effect of Ca(OH)_2 may also be the result of direct inactivation of LPS. The purpose of this study was to investigate whether treatment of Porphyromanas endodonatalis LPS with calcium hydroxide alters its biological action as neasured by human PMN secretion of IL-1 and TNF-α, and it was compared with Escherichia coli LPS. P.endodonatalis ATCC 35406 was cultured in anaerobic condition, and LPS was extracted using the hot-phenol water extraction method and purified. Purchased E. coli LPS was also purified . 100 ㎍/ml of each LPS in pyrogen free water were incubated with 25mg/ml Ca(OH)_2 at 37℃ for 7 days. The supernatants were subjected to ultrafiltration. And the isolates were lyophilized and weighed. PMNs were obtained from peripheral blood by centrifugation layered over Lymphoprep. The cells were resuspended (4 × 10^6 cells/ml) in RPMI 1640 followed by treatment with various concentrations of LPS (0, 0.1, 1, 10㎍/ml) for 24 hours at 37℃ in 5% CO_2 incubator. The supernatants of cells were collected and the levels of IL-1α, IL-1β and TNF-α were measured by enzyme-linked immunosorbent assay. The results were as follows; 1. The levels of IL-1α, IL-1β, TNF-α from PMN treated with each LPS were significantly higher than those released from unstimulated PMN of the control group (p<0.05). 2. The levels of all three cytokines released from PMN stimulated with each calcium hydroxide treated LPS were significantly lower than those released from PMN stimulated with each untreated LPS (p<0.05). while they were not significantly different from those released from unstimulated PMN of the control group (p>0.05). 3. The levels of secretion or all three cytokines were affected in a dose-dependent manner in PMN stimulated with each LPS (p<0.05), but not in PMN stimulated with each calcium hydroxide treated LPS (p>0.05). 4. The levels of all three cytokines released from PMN stimulated with P.endodontalis LPS were significantly lower than those released from PMN stimulated with E. coli LPS (p<0.05).
Wave energy-assisted fluidic self-assembly of LED chips for display applications
Je Jun Ryu,Seong Hyeon Noh,Selim Yun,Chang Wan Park,Seungje Lee,Young Rag Do,Jae Soo Yoo 한국정보디스플레이학회 2022 Journal of information display Vol.23 No.4
Micro-light-emitting diode (micro-LED) displays have excellent image characteristics, particularly in terms of contrast ratio, response to electric field, and color expressions. However, these are expensive due to the price of the LED chips. This can be overcome by reducing the size of the LED chip, but the efficiency will decrease as a result. Moreover, the rapid and accurate arrangement of a few million chips with a size of ∼50μm to form pixels on the substrate is a challenging task. In this study, fluidic self-assembly process was introduced. The self-assembly design and implementation were limited to building a micro-scale system. With geometric constraints, external forces may influence the outcome of a self-assembled product. In this case, wave energy was used as the external force to manipulate the LED chips on the substrate. Target-generated waveforms in the fluid were used to control the movement of the LED chips. The arrays of the LED chips were arranged on a fine metal mask, i.e. transfer cartridge. The chips were then transferred to a circuit-printed glass plate by face-toface pressing under high temperature and high pressure. It was found that the wave energy-assisted self-assembly is applicable and beneficial to LED module fabrication.
Effects of Electron Donors on Nitrate Removal by Nitrate and Nitrite Reductases
Yoo, Young-Je,Sung, Dong-Won,Song, Seung-Hoon,Kim, Ji-Hyeon The Korean Society for Biotechnology and Bioengine 2002 Biotechnology and Bioprocess Engineering Vol.7 No.2
Effects of artificial electron donors to deliver reducing power on enzymic denitrification were investigated using nitrate reductase and nitrite reductase obtained from Ochrobactrum antroyi. The activity of nitrite reductase in the soluble portion was almost the same as that in the precipitated portion of the cell extract. Nitrate removal efficiency was higher with benzyl viologen than with methyl viologen or NADH as an artificial electron donor. The turn-over numbers of nitrate and nitrite reductase were 14.1 and 1.9 umol of nitrogen reduced/min$.$mg cell extracts, respectively when benzyl viologen was used as an electron donor.
유영제,김지현,양대창 한국화학공학회 1997 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.35 No.1
플라스틱 담체(PVC)표면을 화학적으로 전처리하여 활성오니의 부착을 촉진시키고자 하였다. 고정화된 미생물량을 근거로 여러 전처리 방법들의 효율을 비교한 기초 실험에서는 chlorosulfonic acid에 의한 chemical etohing과 PEI(polyethylenimine) 처리를 병행하는 것이 다른 방법에 비해 2-5배의 부착 촉진 효과를 보였다. 이때 측정된 부착량은 2.5g/㎡이며, 전처리를 하지 않은 담체에서는 부착이 거의 일어나지 않았다. 전처리된 담체를 이용하여 PEI의 농도, 부유 미생물의 농도 (MLSS), 기질의 농도 등이 활성오니의 부착에 미치는 영향을 고찰하였다. 결정된 각 인자들의 최적치를 연속 반응기에 응용하여 미생물의 부착실험을 수행한 결과 정상상태의 생물막 형성기간을 기존의 공정에 비해 2-3배 단축할 수 있었다. This study was performed to improve the biofilm formation on the plastic support(PVC) through chemical modification of its surface. The method using chlorosulfonic acid and PEI(polyethylenimine) showed 2-5 times higher attached biomass than the results obtained with other treatments. In this test, the amount of attached dry cell weight was 2.5g/㎡, while that from the untreated support was negligible. Effects of several factors such as PEI concentration, suspended cell mass. substrate concentration on the biofilm formation were investigated. It was confirmed that the time required for the biofilm formation on the new plastic support could be shortened 2-3 times compared to that of conventional systems.
Effects of Electron Donors on Nitrate Removal by Nitrate and Nitrite Reductases
Young Je Yoo,송승훈,Dong Won Sung,Ji Hyeon Kim 한국생물공학회 2002 Biotechnology and Bioprocess Engineering Vol.7 No.2
Effects of artificial electron donors to deliver reducing power on enzymic denitrification were investigated using nitrate reductase and nitrite reductase obtained from Ochrobactrum antropi. The activity of nitrite reductase in the soluble portion was almost the same as that in the precipitated portion of the cell extract. Nitrate removal efficiency was higher with benzyl viologen than with methyl viologen or NADH as an artificial electron donor. The turn-over numbers of nitrate and nitrite reductase were 14.1 and 1.9 mmol of nitrogen reduced/min × mg cell extracts, respectively when benzyl viologen was used as an electron donor.