• 한국전기전자재료학회논문지
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• 제34권4호
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• pp.251-255
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• 2021

a-Si is commonly considered as a primary candidate for the formation of passivation layer in heterojunction (HIT) solar cells. However, there are some problems when using this material such as significant losses due to recombination and parasitic absorption. To reduce these problems, a wide bandgap material is needed. A wide bandgap has a positive influence on effective transmittance, reduction of the parasitic absorption, and prevention of unnecessary epitaxial growth. In this paper, the adoption of a-SiO_x:H as the intrinsic layer was discussed. To increase lifetime and conductivity, oxygen concentration control is crucial because it is correlated with the thickness, bonding defect, interface density (D_it), and band offset. A thick oxygen-rich layer causes the lifetime and the implied open-circuit voltage to drop. Furthermore the thicker the layer gets, the more free hydrogen atoms are etched in thin films, which worsens the passivation quality and the efficiency of solar cells. Previous studies revealed that the lifetime and the implied voltage decreased when the a-SiOx thickness went beyond around 9 nm. In addition to this, oxygen acted as a defect in the intrinsic layer. The D_it increased up to an oxygen rate on the order of 8%. Beyond 8%, the D_it was constant. By controlling the oxygen concentration properly and achieving a thin layer, high-efficiency HIT solar cells can be fabricated.

• Animal Bioscience
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• 제34권4호
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• pp.546-557
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• 2021

Objective: If fertilization does not occur within a specific period, the quality of unfertilized oocytes in the oviduct (in vivo aging) or in culture (in vitro aging) will deteriorate over time. Icariin (ICA), found in all species of Epimedium herbs, has strong antioxidant activity, and is thought to exert anti-aging effects in vitro. We asked whether ICA protects oocytes against age-related changes in vitro. Methods: We analyzed the reactive oxygen species (ROS) levels and expression of antioxidant, maternal, and estrogen receptor genes, and along with spindle morphology, and the developmental competence and quality of embryos in the presence and absence of ICA. Results: Treatment with 5 μM ICA (ICA-5) led to a significant reduction in ROS activity, but increased mRNA expression of glutathione and antioxidant genes (superoxide dismutase 1 [SOD1], SOD2, peroxiredoxin 5, and nuclear factor erythroid 2-like 2), during aging in vitro. In addition, ICA-5 prevented defects in spindle formation and chromosomal alignment, and increased mRNA expression of cytoplasmic maturation factor genes (bone morphogenetic protein 15, cyclin B1, MOS proto-oncogene, serine/threonine kinase, and growth differentiation factor-9). It also prevented apoptosis, increased mRNA expression of antiapoptotic genes (BCL2-like 1 and baculoviral IAP repeat-containing 5), and reduced mRNA expression of pro-apoptotic genes (BCL2 antagonist/killer 1 and activation of caspase-3). Although the maturation and cleavage rates were similar in all groups, the total cell number per blastocyst and the percentage of apoptotic cells at the blastocyst stage were higher and lower, respectively, in the control and ICA-5 groups than in the aging group. Conclusion: ICA protects oocytes against damage during aging in vitro; therefore, it can be used to improve assisted reproductive technologies.

• 한국식품위생안전성학회지
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• 제35권6호
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• pp.535-543
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• 2020

유전적 조절, 유전자 발현 그리고 환경적 단서, 화학적 신호에 대응하는 표현형 변이에서 세포 RNA는 ubiquitous 역할 이외에도 세포 외 RNA(exRNA)라 하는 새로운 형태의 RNA는 추후 연구의 방향을 제시한다. exRNA는 membrane vesicles 또는 세포 외 소포체(EV)로 알려진 membrane blebs를 통해 세포 외부로 운반된다. EV의 형성은 원핵생물, 진핵생물, 고세균을 포함한 모든 미생물군에 우세하게 보존되어있다. 본 리뷰는 세균 유래 exRNA에 관해 세가지 주제에 초점을 두었다. exRNA의 발견과 박테리아 유전자 배열에 대한 외부 RNA의 영향, b. exRNA의 분비기작을 통한 방출, c. 다른 그람음성 및 그람양성균에 의해 분비되는 exRNA로 고안될 수 있는 응용 가능분야이다. 본 리뷰에서 장내 미생물군의 probiotics 및 후성유전학적 규제에서 본 exRNA와 exRNA마커와 같은 EV파생 응용프로그램에 대한 의견을 제공할 것이다.

• 상하수도학회지
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• 제35권6호
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• pp.405-415
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• 2021

MMBR system has been suggested as a promising system to resolve harvesting problems induced from low settling efficiency of microalgae. And recently, a lot of research on reducing fouling at the MMBR system has investigated focused on EPS in many cases. EPS of microalgae mainly consists of polysaccharides and protein components, and is produced through photosynthesis and nitrogen-carbon metabolic pathways. Especially, P-EPS is one of major compounds which occur membrane fouling phenomenon, as its hydrophobic protein components cause floc formation and cake layer accumulation. And it is already known that almost every microalgae can metabolize P-EPS or Chl-a when nitrogen sources as a substrate is insufficient or exhausted situation. With the above backgrounds, uptake rates of P-EPS or Chl-a by Scenedesmus quadricauda according to the type of carbon source and nitrogen concentration were evaluated in order to verify correlation between carbon source vs P-EPS production, and indeed Scenedesmus quadricauda uses P-EPS or Chl-a when the amounts of nitrogen sourc es in the feed is not satisfied. As a result, it was shown that P-EPS and Chl-a production were increased proportional to nitrogen concentration under organic carbon condition. And especially, the amo unts of P-EPS and Chl-a in the cell were diminished with the nitrogen source becomes insufficient or exhausted. Because P-EPS accelerates fouling at the MMBR system, P-EPS degradation by Scenedesmus quadricauda in order to get nitrogen source may contribute to reducing fouling. About a affects of N-consumed Chl-a to the MMBR fouling, more survey is needed. On the contrary, considering the purpose of MMBR system of this study, i.e. harvesting useful high value microalgae efficiently feeding adequate industrial process wastewater, it seems like difficult to maintain satisfied metabolic activity and to harvest with high yield rate using nitrogen-poor MMBR feed.

• 생명과학회지
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• 제32권1호
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• pp.51-55
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• 2022

Matrix metalloproteinases (MMPs)는 세포의 기저막 분해에 관여하는 효소로 과발현된 MMPs는 암세포 침윤과 전이에 직접적인 영향을 주는 것으로 알려져 있다. 본 연구에서는 항산화, 항염증, 항균활성 있는 것으로 보고되어 있는 염주괴불주머니 추출물을 이용하여 PMA로 유도된 인간 섬유육종세포 HT-1080 세포에서 MMP-2, MMP-9의 발현 조절에 미치는 영향을 확인하였다. 그 결과 염주괴불주머니 추출물은 TIMP-1 및 TIMP-2를 증가시키면서 MMP-2 및 MMP-9의 mRNA 및 단백질 발현 수준을 모두 감소시키는 것으로 나타났다. 또한 p38, JNK, ERK의 인산화를 억제하였으며, 이를 통해 염주괴불주머니 추출물은 MAPKs 신호 전달 경로 조절에 영향을 줌으로써 MMPs 발현을 감소시키는 것을 확인할 수 있었다. 따라서 이러한 연구의 결과는 염주괴불주머니를 이용한 암 전이 억제 소재 개발을 위한 기초자료로 활용될 수 있을 것으로 기대된다.

• 대한화장품학회지
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• 제48권3호
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• pp.287-293
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• 2022

흰머리는 대표적인 노화의 징후이자 피부, 모발 노화의 특징이다. 내인성 노화, 스트레스, 외부 환경으로 인해 백모가 발생하는데, 조기 백모 발생에는 스트레스가 주요한 요인이 된다고 알려져 있다. 과거 우리는 갈근 추출물이 멜라닌 형성 촉진을 통해 백모를 케어를 할 수 있음을 밝힌 바 있으며, 이에 갈근 추출물이 스트레스에 의한 백모 형성 또한 예방 할 수 있을지 본 연구를 통해 확인하였다. 연구를 위해 멜라닌 생성 주요 전사인자인 MITF 발현을 확인 할 수 있는 세포주를 구축하였다. 스트레스 호르몬 cortisol과 산화 스트레스 유발 인자 H₂O₂를 처리할 경우 MITF 발현이 감소하고, 인체 모낭 조직에서 멜라닌 색소가 감소함을 확인하였다. 여기에 갈근 추출물을 함께 처리할 경우 MITF 발현과 모낭 내 멜라닌 색소 량이 다시 증가하였다. 뿐만 아니라 모낭 내 멜라닌 합성에 관여하는 효소인 TRP-2의 발현도 증가함을 확인할 수 있었다. 이러한 결과를 통해 갈근 추출물은 스트레스 호르몬과 산화 스트레스 자극에 의한 멜라닌 합성 저해도 효과적으로 막아줄 수 있음을 입증하였다.

• 한방비만학회지
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• 제22권1호
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• pp.30-37
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• 2022

Objectives: Adipogenesis is the process by which pre-adipocytes are differentiated into adipocytes. It also plays an important role in adipocyte formation and lipid accumulation. Ranunculus sceleratus (R. sceleratus) extracts are used for the treatment of various diseases such as hepatitis, jaundice, and tuberous lymphadenitis in oriental medicine. However, its effect on adipogenesis has not yet been studied. In this study, we investigated the effects of R. sceleratus on adipogenesis in 3T3-L1 cells. Methods: Cells were treated with 50, 100, and 200 ㎍/ml of R. sceleratus and cell viability was evaluated. To differentiate the 3T3-L1 preadipocytes, a 3-isobutyl-1-methylxanthine, dexamethasone, and insulin (MDI) solution were used. The accumulation of lipid droplets was determined by Oil Red O staining. The expression levels of adipogenesis-related proteins were also determined. Results: MDI solution differentiated the preadipocytes into adipocytes and accumulation of lipids was observed in the differentiated 3T3-L1 cells. Interestingly, the amount of lipid droplets was reduced after R. sceleratus treatment. In addition, the expression levels of key adipogenic transcription factors, such as CCAAT/enhancer-binding proteins-𝛼 (C/EBP-𝛼) and peroxisome proliferator-activated receptors-𝛾 (PPAR-𝛾) were also reduced after R. sceleratus treatment. Furthermore, R. sceleratus increased AMP-activated kinase (AMPK) phosphorylation and decreased sterol regulatory element-binding protein-1 expression. Conclusions: Our results showed that R. sceleratus reduced preadipocyte differentiation by inhibiting C/EBP-𝛼 and PPAR-𝛾 levels via the AMPK pathway. Therefore, we suggest that R. sceleratus may be potentially used as an anti-adipogenic agent.

• Journal of Ginseng Research
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• 제47권2호
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• pp.337-346
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• 2023

Background: Ginsenoside Rb2, a major active component of Panax ginseng, has various physiological activities, including anticancer and anti-inflammatory effects. However, the mechanisms underlying the rejuvenation effect of Rb2 in human skin cells have not been elucidated. Methods: We performed a senescence-associated β-galactosidase staining assay to confirm cellular senescence in human dermal fibroblasts (HDFs). The regulatory effects of Rb2 on autophagy were evaluated by analyzing the expression of autophagy marker proteins, such as microtubule-associated protein 1A/1B-light chain (LC) 3 and p62, using immunoblotting. Autophagosome and autolysosome formation was monitored using transmission electron microscopy. Autophagic flux was analyzed using tandem-labeled GFP-RFP-LC3, and lysosomal function was assessed with Lysotracker. We performed RNA sequencing to identify potential target genes related to HDF rejuvenation mediated by Rb2. To verify the functions of the target genes, we silenced them using shRNAs. Results: Rb2 decreased β-galactosidase activity and altered the expression of cell cycle regulatory proteins in senescent HDFs. Rb2 markedly induced the conversion of LC3-I to LC3-II and LC3 puncta. Moreover, Rb2 increased lysosomal function and red puncta in tandem-labeled GFP-RFP-LC3, which indicate that Rb2 promoted autophagic flux. RNA sequencing data showed that the expression of DNA damage-regulated autophagy modulator 2 (DRAM2) was induced by Rb2. In autophagy signaling, Rb2 activated the AMPK-ULK1 pathway and inactivated mTOR. DRAM2 knockdown inhibited autophagy and Rb2-restored cellular senescence. Conclusion: Rb2 reverses cellular senescence by activating autophagy via the AMPK-mTOR pathway and induction of DRAM2, suggesting that Rb2 might have potential value as an antiaging agent.

• 생명과학회지
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• 제33권1호
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• pp.102-113
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• 2023

본 총설에서는 지난 수년 동안 자궁내막 염증 관련 새롭게 밝혀진 에스트로겐과 프로게스테론 수용체의 기능 중 지엽적 에스트로겐의 합성, 특이적 에스트로겐 수용체의 조절, 프로게스테론 저항성 그리고 스테로이드 호르몬의 작용에 의한 자궁내막 조직세포의 염증반응, 분화 및 생존에 대한 세포 및 분자적 조절기전들을 고찰한다. 자궁내막 조직 기질세포의 비정상적인 후성유전체적 변화는 자궁내막증의 발병과 진행에 중요한 요인으로 작용한다. 특히, 에스트로겐 수용체 유전자들의 차별적 메틸화는 기질세포내 ERα로부터 ERβ로의 발현 우세도 전환을 유도하여, ERβ-매개 염증반응, 프로게스테론 저항성 및 레티노이드 합성장애 등의 비정상적인 에스트로겐 반응을 초래한다. 이 기질세포는 또한 PGE2 및 SF-1 매개에 의한 스테로이드 합성효소의 발현유도를 통하여 지엽적 에스트로겐의 생성을 촉진하며, 증가된 에스트라디올은 다시 ERβ에 피드백으로 작용하여 COX-2 촉진을 통한 염증반응의 악순환을 야기한다. 높은 ERβ의 발현은 중간엽 줄기세포의 염색질 구조변화릉 야기하여 프로게스테론 저항성을 획득하고, 이는 반복적 생리에 따른 지속적 노출로 자궁내막 조직의 염증을 형성하며, 이후에는 ERβ-매개 에스트로겐과 TNF-α 및 TGF-β1을 포함한 염증 유발 인자들이 작용하여 염증 조직세포의 부착, 혈관생성 및 생존과 기질세포의 분화조절장애를 유도한다. 따라서, 생리주기의 역동적인 호르몬 변화와 이에 따르는 자궁내막 조직의 핵수용체 신호전달 조절기전에 대한 구체적인 이해는 정상적인 생식기능을 유지하면서 자궁내막증과 같은 비정상적 염증질환을 치료하기 위한 새로운 안목을 제공할 수 있을 것으로 기대된다.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.63-63
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• 2003

This study was carried out to investigate the effects of liquid boar sperm stored at 4$^{\circ}C$ on sperm motility, normal acrosome, and in-vitro fertilization and culture of pig oocytes matured in-vitro. The sperm-rich fraction (30~60 ml) of ejaculate was collected into an insulated vacuum bottle. Semen was slowly cooled to room temperature (20~23$^{\circ}C$) by 2 h after collection. Semen was transferred into 15 ml tubes, centrifuged at room temperature for 10 min at 800$\times$g, and the supernatant solution was poured off. The concentrated sperm was resuspended with 5 ml of lactose, egg yolk and N-acetyl-D-glucosamine (LEN) diluent to provide 1.0$\times$10$^{9}$ sperm/ml at room temperature. The resuspended semen was cooled in a refrigerator to 4$^{\circ}C$ and preserved for 5 days to examine sperm motility and normal acrosome. The medium used for oocyte maturation was modified tissue culture medium (TCM) 199. After about 22 h of culture, oocytes were cultured without cysteamine and hormones for 22 h at 38.5$^{\circ}C$, 5% $CO_2$ in air. Oocytes were inseminated with liquid boar sperm stored at 4$^{\circ}C$ for 2 days after collection. Oocytes were coincubated for 6 h in 500 ${mu}ell$ mTBM fertilization media with 0.2, 1, 5 and 10$\times$10$^{6}$ /ml sperm concentration, respectively. At 6 h after IVF, oocytes were transferred into 500 ${mu}ell$ Hepes-buffered NCSU-23 culture medium for further culture of 6, 48 and 144 h. There were significant differences in sperm motility and normal acrosome among preservation days and incubation times, respectively. The rates of sperm penetration and polyspermy were higher in 5 and 10$\times$10$^{6}$ sperm/ml than in 0.2 and 1$\times$10$^{6}$ sperm/ml. Male pronuclear formation was lower in 0.2$\times$10$^{6}$ sperm/ml than in 1, 5 and 10$\times$10$^{6}$ sperm/ml. Mean numbers of sperm in penetrated oocyte were highest in 10$\times$10$^{6}$ sperm/ml compared with other sperm concentrations. The rate of blastocysts from the cleaved oocytes (2~4 cell stage) was highest in 1$\times$10$^{6}$ sperm/ml compared with other sperm concentrations. In conclusion, we found out that liquid boar sperm stored at 4$^{\circ}C$ could be used for in-vitro fertilization of pig oocytes matured in-vitro. Also, we recommend 1$\times$10$^{6}$ ml sperm concentration for in-vitro fertilization of pig oocytes.