• 멤브레인
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• 제26권2호
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• pp.126-134
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• 2016

바이오 가스로부터 바이오 메탄을 생산하기 위해 물리흡수제 특성평가 및 $CO_2/CH_4$흡수 연구를 진행하였고, poly-propylene(PP) 중공사막 막접촉기에 적용해보았다. 물리흡수제 중 propylene carbonate (PC)는 PP 중공사막과 가장 높은 $58.3^{\circ}$ 접촉각을 보였고, 5 wt% PC를 물과 혼합할 경우 $90^{\circ}$ 이상의 접촉각이 관찰되었다. 또한 $CO_2$ 흡수실험에서 PC/물 혼합 흡수제는 물 흡수량(0.121 mmol/g) 보다 높은 0.148-0.157 mmol/g의 흡수량을 보이며, 막접촉기에 가장 적합한 물리흡수제로 선정되었다. PC/물 혼합 흡수제를 막접촉기에 적용 후 얻어진 $CO_2$ 제거율(98.0-97.8%)과 $CH_4$ 순도(98.5-98.3%)는 바이오 메탄으로서 매우 높은 가능성을 보여주었다. 하지만 PC/물 혼합 흡수제의 경우에는 물 흡수제와 비교하여 성능 변화가 매우 미비하였다. 이는 물보다 우수한 PC 흡수능과 함께 그에 따른 막접촉기 탈기 막 모듈 및 시스템 개선과 공급 유량 조절을 통해 $CH_4$ 손실 최소화 등 공정 최적화가 필요한 것으로 분석된다.

• 한국어병학회지
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• 제17권2호
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• pp.131-137
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• 2004

본 실험은 넙치 (Paralichthys olivaceus) 간으로부터 membrane부분에 존재하는 PC 가수분해 효소의 특성에 대해 조사하였다. 먼저 간 조직을 초고속 원심 분리기와 nonion-detergent인 1% triton X - 100을 이용하여 membrane 부분을 분리하였으며, Heprain-Sepharose CL-6B 칼럼과 Heparin-5PW 칼럼을 이용하여 분리정제 하였다. 얻어진 PC 가수분해효소에 대한 반응 ․ 생성물을 확인하기 위해 autoradiography를 실시하였다. 지용성 부분의 결과에서 transphosphatidylation 반응의 결과물인 PEtOH을 형성하는 것으로 보아 PC-PLD임을 알 수 있었다. 얻어진 PC 가수분해효소에 대한 생화학적 특성을 조사한 결과 적정 pH가 6.5이하인 산성 조건 및 $37^\circ{C}$의 배양온도에서 최고 활성을 나타내었으며, 이가 이온들에 대한 영향의 경우 칼슘은 1.67mM 농도에서 최고 활성을 나타냈으나, 마그네슘은 활성에 영향을 미치지 않았다. 각종 세포막 기질에 대한 영향을 조사한 결과 PC는 $0.75\mu{M}$, PIP2는 $2.35\mu{M}$, PE는 $26.8\mu{M}$ 농도에서 최고 활성을 나타내었다. 이상의 결과부터 넙치 간조직의 막층부분에 존재하는 PC를 가수분해효소는 PC-PLD가 존재함을 알 수 있었다.

• Biomolecules & Therapeutics
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• 제11권2호
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• pp.112-118
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• 2003

1-Methylated $\beta$-carbolines (harmaline and harmalol) and antioxidants (N-acetylcysteine and ascorbate) reduced the loss of cell viability in differentiated PC 12 cells treated with 5 mM glutamate. $\beta$-Carbolines prevented the glutamate-induced decrease in mitochondrial membrane potential, cytochrome c release and caspase-3 activation in PC 12 cells. $\beta$-Carbolines reduced the formation of reactive oxygen species and depletion of glutathione due to glutamate in PC12 cells. $\beta$-Carbolines revealed a scavenging action on hydrogen peroxide and reduced the iron and EDTA-mediated degradation of 2-deoxy-D-ribose. The results suggest that I-methylated $\beta$-carbolines attenuate the cytotoxic effect of glutamate on PC12 cells by reducing the alteration of mitochondrial membrane permeability that seems to be mediated by oxidative stress.

• Biomolecules & Therapeutics
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• 제12권1호
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• pp.9-18
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• 2004

Opening of the mitochondrial permeability transition pore has been recognized to be involved in cell death. The present study investigated the effect of ${\beta}$-carbolines (harmaline and harmalol) and deprenyl on the dopamine-induced change in the mitochondrial membrane permeability and cell death in differentiated PC12 cells. Cell death due to 250 4{\mu}$M dopamine was inhibited by caspase inhibitors (z-IETD.fmk, z-LEHD.fmk and z-DQMD.fmk) and antioxidants (N-acetylcysteine, ascorbate, superoxide dismutase, catalase and carboxy-PTIO). ${\beta}$-Carbolines prevented the dopamine-induced cell death in PCl2 cells, while deprenyl did not inhibit cell death. ${\beta}$-Carbolines decreased the condensation and fragmentation of nuclei caused by dopamine in PC12 cells. ${\beta}$-Carbolines inhibited the decrease in mitochondrial transmembrane potential, cytochrome c release, formation of reactive oxygen species and depletion of GSH caused by dopamine in PC12 cells, whereas deprenyl did not decrease dopamine-induced mitochondrial damage. ${\beta}$-Carbolines, deprenyl and antioxidants depressed the formation of nitric oxide and melanin in dopamine-treated PC12 cells. The results suggest that cell death due to dopamine PC12 cells is mediated by caspase-8, -9 and -3. Unlike deprenyl, ${\beta}$-carbolines may attenuate the dopamineinduced cell death in PC12 cells by suppressing change in the mitochondrial membrane permeability through inhibition of the toxic action of reactive oxygen and nitrogen species.

• 한국산업융합학회 논문집
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• 제4권1호
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• pp.61-69
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• 2001

Polycarbonate(PC) membranes for oxygen enrichment from air were prepared by the wet phase inversion method. In order to improve oxygen separation performances of the PC membrane, the effect of the added ethanol(nonsolvent) and $CuCl_2$(metal salt) concentration in the casting solution on morphology, oxygen permeability ami $O_2/N_2$ separation factor of the membrane was studied. In addition, tensile strength and elongation at break of the membrane were investigated. An asymmetric membrane with a dense top layer and a porous sublayer was obtained. The thickness of the dense top layer decreased with increasing amount of nonsolvent additive. Compared with pure PC membrane without additive(metal salt), the oxygen permeability and $O_2/N_2$ separation factor of the $PC/CuCl_2$ membrane are significantly improved. The oxygen permeability and $O_2/N_2$ separation factor is $5.25{\times}10^{-9}cm^3(STP){\cdot}cm/cm^2{\cdot}sec{\cdot}cmHg$ and 4.5, respectively. This improvement might be due to good interaction between metal salt and oxygen.

• 한국가스학회지
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• 제13권1호
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• pp.21-27
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• 2009

본 논문은 특별한 주름을 갖는 멤브레인 패널로 제작한 LNG 저장탱크용 예응력 콘크리트(PC) 외부탱크에 대한 강도안전성 연구를 수행하였다. 강도안전성을 유한요소법으로 해석하기 위해 멤브레인 패널로 제작한 내부탱크가 파손되면서 저장된 LNG가 PC 외부탱크로 누설되었다고 가정한다. 본 연구는 누설 LNG에 의해 발생하는 유체정압과 자중량, 온도차 하중, PC 구조물의 자중량, 증발가스 압력에 의해 형성되는 5가지의 복합하중에 대해 외부탱크에 작용하는 응력과 변형거동을 해석하였다. FEM 해석결과에 의하면, 멤브레인으로 제작된 내부탱크로부터 LNG가 누설되어도 200,000$m^3$의 저장용량을 갖는 LNG 외부탱크(PC 콘크리트 구조물)는 충분한 강도안전성을 갖지만, 누설 LNG에 의한 초저온 하중이 더욱 증가하게 되면 PC 외부탱크 구조물의 강도안전성은 계속 떨어지고, 궁극적으로 외부탱크의 붕괴로 발전할 수 있다는 점에 주의해야 한다.

• 멤브레인
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• 제21권3호
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• pp.256-262
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• 2011

저농도의 $SF_6$를 포함하고 있는 기체 혼합물(10% $SF_6$/70% $N_2$/19% $O_2$/1% $CF_4$)로부터 $SF_6$를 분리 및 회수하기 위한 PSF막과 PC막의 성능에 대하여 연구하였다. 회수된 기체 내의 $SF_6$의 농도와 회수율 그리고 혼합기체($N_2/SF_6$, $O_2/SF_6$, $CF_4/SF_6$)의 선택도는 배출 유량과 온도의 함수로 측정하였다. PSF막과 PC막 모두 회수된 기체 내의 $SF_6$ 농도는 배출 유량이 증가하면서 감소하였으며 온도가 증가함에 따라 증가하였다. 동일한 실험조건에서는 PSF막에서 회수된 기체 내의 $SF_6$의 농도가 PC막에서보다 높게 나타났다. 최대회수율은 298.15 K과 배출유량 150cc/min에서 PSF막의 경우 95.9%이고 PC막의 경우 67.8%를 나타냈다. $CF_4/SF_6$를 제외한 $N_2/SF_6$와 $O_2/SF_6$의 실제 선택도는 PSF막이 PC막보다 더 높게 나타났다.

• BMB Reports
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• 제31권5호
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• pp.468-474
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• 1998

Membrane depolarization in PC12 cells induces calcium influx via an L-type voltage-sensitive calcium channel (L-VSCC) and increases intracellular free calcium, which leads to tyrosine phosphorylation of epidermal growth factor (EGF) receptor and the associated adaptor protein, She. This activated EGF receptor complex then can activate mitogen-activated protein (MAP) kinase, as in nerve growth factor (NGF) receptor activation. In the present study, we investigated the role of EGF receptor in the signaling pathway initiated by membrane depolarization of PC12 cells. Prolonged membrane depolarization induced phosphorylation of extracellular signal-regulated kinase (ERK) within 1 min in undifferentiated PC12 cells. Pretreatment of PC12 cells with the calcium chelator EGTA abolished depolarization-stimulated ERK phosphorylation, but NGF-induced phosphorylation of ERK was not affected. The chronic treatment of phorbol ester, which down-regulated the activity of protein kinase C (PKC), did not affect the phosphorylation of ERK upon depolarization. In the presence of an inhibitor of EGF receptor, neither depolarization nor calcium ionophore increased the level of ERK phosphorylation. These data imply that the EGF receptor is functionally necessary to activate ERK and neurite outgrowth in response to the prolonged depolarization in PC12 cells, and also that PKC is apparently not involved in this signaling pathway.

• The Korean Journal of Physiology and Pharmacology
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• 제10권1호
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• pp.51-58
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• 2006

The promoting effect of hydrogen peroxide ($H_2O_2$) against the cytotoxicity of 1-methyl-4-phenylpyridinium ($MPP^+$) in differentiated PC12 cells was assessed by measuring the effect on the mitochondrial membrane permeability. Treatment of PC12 cells with $MPP^+$ resulted in the nuclear damage, decrease in the mitochondrial transmembrane potential, cytosolic accumulation of cytochrome c, activation of caspase-3, increase in the formation of reactive oxygen species (ROS) and depletion of GSH. Addition of $H_2O_2$ enhanced the $MPP^+-induced$ nuclear damage and cell death. Catalase, Carboxy-PTIO, Mn-TBAP, N-acetylcysteine, cyclosporin A and trifluoperazine inhibited the cytotoxic effect of $MPP^+$ in the presence of $H_2O_2$. Addition of $H_2O_2$ promoted the change in the mitochondrial membrane permeability, ROS formation and decrease in GSH contents due to $MPP^+$ in PC12 cells. The results show that the $H_2O_2$ treatment promotes the cytotoxicity of $MPP^+$ against PC12 cells. $H_2O_2$ may enhance the $MPP^+$-induced viability loss in PC12 cells by promoting the mitochondrial membrane permeability change, release of cytochrome c and subsequent activation of caspase-3, which is associated with the increased formation of ROS and depletion of GSH. The findings suggest that $H_2O_2$ as a promoting agent for the formation of mitochondrial permeability transition may enhance the neuronal cell injury caused by neurotoxins.

• Journal of Microbiology and Biotechnology
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• 제17권2호
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• pp.373-377
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• 2007

No phosphatidylcholine (PC) was detected in the membrane of Rhodobacter sphaeroides pmtA mutant (PmtAl) lacking phosphatidylethanolamine (PE) N-methyltransferase, whereas PE in the mutant was increased up to the mole % comparable to the combined level of PE and PC of wild type. Neither the fatty acid composition nor the fluidity of membrane was altered by pmtA mutation. Consistently, aerobic and photoheterotrophic growth of PmtAl were not different from wild type. However, PmtAl showed an extended lag phase (15 h) after the growth transition from aerobic to photoheterotrophic conditions, indicating the PC requirement for the efficient formation of intracytoplasmic membrane (ICM). Interestingly, the B800-850 complex of PmtAl was decreased more than twofold in comparison with wild type, whereas the level of the B875 complex comprising the fixed photosynthetic unit was not changed. Since puc expression is not affected by pmtA mutation, PC appears to be required for the proper formation of the B800-850 complex in the ICM of R. sphaeroides.