• 한국산학기술학회논문지
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• 제19권8호
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• pp.105-114
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• 2018

전기응집 (Electro-coagulation)을 활용한 분리 막 생물반응기 (Membrane Bio-Reactor) 공정의 막 오염 저감 현상을 확인하고 이를 해석하고자 하였다. 전기응집의 주요 운전 인자인 전류밀도와 접촉시간 변화가 활성슬러지 혼합액의 막 여과에 미치는 영향을 관찰하고 전기응집 과정에서 발생하는 수산화금속염이 막 오염에 미치는 역할에 대해 연구하였다. 전류밀도를 $10A/m^2$으로 높게 유지한 경우에는 전기응집 시간이 증가하여도 막 오염 감소 효과가 크지 않은 반면 $2.5A/m^2$의 낮은 전류밀도 하에서는 전기응집 시간이 증가하면 추가적인 막 오염 감소가 관찰되었다. 즉, 막 오염을 감소시키는 전류밀도와 접촉시간의 곱이 전체 막 오염 저감 정도를 지배하고 있음을 확인하였다. 또한 주어진 전류밀도와 인가시간에서 입도분포는 크게 변화하지 않은 것으로 나타나 콜로이드 입자와 막 오염 저감과는 큰 관련성이 없는 것으로 판단되었다. 그러나 전기응집을 통해 생성된 수산화알루미늄 (인산알루미늄)이 막 여과 과정에서 동적 막 (Dynamic Membrane)을 형성하여 막 오염 현상을 완화하는 것으로 확인되었다. 전기응집에서 발생한 수산화금속염이 막 표면에 동적 막을 형성하고 이로 인해 유입수의 입자성분이 직접 막 표면과 내부에 침적되는 것을 방해하고 동적 막에 주로 쌓이게 함으로써 막 오염이 감소된 것이다. 본 연구에서 밝힌 수산화금속염에 의한 동적 막의 역할은 전기응집을 활용한 MBR 공정의 후 막 오염 감소 메커니즘을 해석하는데 중요한 역할을 한다고 결론지을 수 있다.

• Molecules and Cells
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• 제38권7호
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• pp.657-662
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• 2015

Rapid and efficient engulfment of apoptotic cells is an essential property of phagocytes for removal of the large number of apoptotic cells generated in multicellular organisms. To achieve this, phagocytes need to be able to continuously uptake apoptotic cells. It was recently reported that uncoupling protein 2 (Ucp2) promotes engulfment of apoptotic cells by increasing the phagocytic capacity, thereby allowing cells to continuously ingest apoptotic cells. However, the functions of Ucp2, beyond its possible role in dissipating the mitochondrial membrane potential, that contribute to elevation of the phagocytic capacity have not been determined. Here, we report that the anion transfer or nucleotide binding activity of Ucp2, as well as its dissipation of the mitochondrial membrane potential, is necessary for Ucp2-mediated engulfment of apoptotic cells. To study these properties, we generated Ucp2 mutations that affected three different functions of Ucp2, namely, dissipation of the mitochondrial membrane potential, transfer of anions, and binding of purine nucleotides. Mutations of Ucp2 that affected the proton leak did not enhance the engulfment of apoptotic cells. Although anion transfer and nucleotide binding mutations did not affect the mitochondrial membrane potential, they exerted a dominant-negative effect on Ucp2-mediated engulfment. Furthermore, none of our Ucp2 mutations increased the phagocytic capacity. We conclude that dissipation of the proton gradient by Ucp2 is not the only determinant of the phagocytic capacity and that anion transfer or nucleotide binding by Ucp2 is also essential for Ucp2-mediated engulfment of apoptotic cells.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권6호
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• pp.609-616
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• 2007

Purpose: The aim of the present study was to evaluate the effect of Bio-Oss on bone formation in terms of healing period and type of membrane so that determine the most suitable condition for implant fixation in grafted maxilla. Material & Method: Forty-five biopsy specimens from graft site were evaluated. Sinus lift was performed in the patients with reduced alveolar bone height(less than 5mm). The specimen was taken at the time of implant fixation, which was performed at least 5 months after the sinus lift procedure. All specimens were stained with H&E and Trichrome staining and evaluated histomorphometrically. Result: The results showed that Bio-Oss particle was in direct contact with newly formed bone in all cases. In the present study, the amount of newly formed bone and the residual bone substitute material were not statistically different according to various membrane and different healing period. There was no difference between the histological feature of the specimen of 5 and 31 months. No statistical significance was detected between male and female. Conclusion: The result implies that Bio-Oss does not seem to be resorbed over time regardless of the type of the membranes. The further investigation is needed to clarify this issue with the extended period of follow-up.

• 한국수소및신에너지학회논문집
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• 제19권6호
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• pp.529-536
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• 2008

Cyanobacteria Synechocystis PCC 6803 or the extracted thylakoid membrane from this strain was appled to photosynthetic bio-electrochemical fuel cell(PBEFC) for the production of hydrogen under the illumination of 48Klux using halogen lamp. PBEFC was composed of anode, cathode and membrane between them. Electrode material was carbon paper while electron mediator and receptor were added phenazine methosulfate(PMS) and potassium ferricyanide respectively. When water and 50 mM tricine buffer and $300{\mu}M$ PMS were added to the anode under the light condition, PBEFC produced the current density $4.4{\times}10^{-5}\;mA/cm^2$, $1.4{\times}10^{-4}\;mA/cm^2$ and $2.4{\times}10^{-4}\;mA/cm^2$, respectively. And the addition of the thylakoid membrane to the system increased current density to $1.3{\times}10^{-3}\;mA/cm^2$. Two times increase of the thylakoid membrane into the anode doubled the current density to $2.6{\times}10^{-3}\;mA/cm^2$. But the current density was not increased proportionally to the amount of thylakoid membrane increased. The system was unstable to measure the electricity output due to the foam production in the anode. Addition of triton X-100 and tween 80 stabilized the system to measure the electricity output but the current density was not increased higher than $8.4{\times}10^{-4}\;mA/cm^2$ and $2.3{\times}10^{-3}\;mA/cm^2$. When the thylakoid membrane was substituted to Synechocystis PCC 6803 cells of four-day culture which has chlorophyll contents $20.5{\mu}g/m{\ell}$, maximum current density was $1.3{\times}10^{-3}\;mA/cm^2$ with $1\;k{\Omega}$ resistance.

• 한국자기공명학회논문지
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• 제14권2호
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• pp.88-104
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• 2010

Human melanocortin-4 receptor (hMC4R) has a critical role in part of energy homeostasis, and their heterozygous mutations related in genetic cause of severe human obesity. In order to study the structure and function of these membrane proteins, it is important to prepare the samples. However, the preparation of transmembrane peptide is seriously difficult and time-consuming. Overexpression and purification of membrane proteins was reported to be difficult due to their innate insoluble and toxic properties. Among the many difficulties, the most important is the difficulty in obtaining sufficient quantities of purified protein. Recently, we succeed to produce large amounts of the second transmembrane domain from the wild-type hMC4R (wt-TM2) and D90N mutant hMC4R (m-TM2) and proposed the structural difference of them in membrane-like environments. In this paper, we demonstrate the optimization procedures to express and purify wt-TM2 or m-TM2 peptides, and solution NMR studies in different detergents to get high-resolution spectra were also described.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.547-548
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• 2006

This study focuses on a determination of amount of Pt in the Pt/C for catalysts of polymer electrolyte membrane fuel cells (PEMFC). PEMFC offer low weight and high power density and being considered fur automotive and stationary power applications. The PEMFC behavior is quite complex is influenced by several factors, including catalysts and structure of electrode and membrane type. Catalyst of electrode is important factor for PEMFC. One of the obstacles preventing polymer electrolyte membrane fuel cells from commercialization is the high cost of noble metals to be used as catalyst, such as platinum. To effectively use these metals, they have to be will dispersed to small particles on conductive carbon supports. The optimal amount of Pt in Pt/C was investigated by using polarization curves in single cell with $H_2/O_2$ operation.

• Journal of Microbiology and Biotechnology
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• 제25권6호
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• pp.759-764
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• 2015

Antimicrobial peptides (AMPs) are one of the critical components in host innate immune responses to imbalanced and invading microbial pathogens. Although the antimicrobial activity and mechanism of action have been thoroughly investigated for decades, the exact biological properties of AMPs are still elusive. Most AMPs generally exert the antimicrobial effect by targeting the microbial membrane, such as barrel stave, toroidal, and carpet mechanisms. Thus, the mode of action in model membranes and the discrimination of AMPs to discrepant lipid compositions between mammalian cells and microbial pathogens (cell selectivity) have been studied intensively. However, the latest reports suggest that not only AMPs recently isolated but also well-known membrane-disruptive AMPs play a role in intracellular killing, such as apoptosis induction. In this mini-review, we will review some representative AMPs and their antimicrobial mechanisms and provide new insights into the dual mechanism of AMPs.

• 한국막학회:학술대회논문집
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• 한국막학회 2002년도 추계 총회 및 학술발표회
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• pp.81-83
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• 2002

• 한국막학회:학술대회논문집
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• 한국막학회 2000년도 추계 총회 및 국제학술발표회
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• pp.127-130
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• 2000

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.478-481
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• 2005

In this study optical sensing membrane was developed for the queantification of dissolved carbon dioxide in micro-bioreactor using an immobilized 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS). For the immobilization of HPTS sol-gel was synthesied by using 3-glycidoxypropyl-dimethoxymethylsiline and tetraethyl orthosilicate.