• 한국세라믹학회지
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• 제38권11호
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• pp.1067-1074
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• 2001

수팽윤성 점토로서 벤토나이트(BEN), 유기금속 비누계 건조제, 아크릴계 바인더 및 코팅첨가제들을 배합하여 서로 성분이 다른 자동산화 건조형 수성코팅제(WBC-1, WBC-2, WBC-3, WBC-4) 4종류를 제조하였다. 제조한 수성코팅제(WBC)의 용액점도, 고형분, 유동학적인 성질 및 자동산화 건조성을 조사하였다. 또한 주조된 WBC 필름의 열안정성, 투명성 및 내수성을 측정하였고, WBC 필름의 표면형상을 주사탐침현미경으로 조사하였다. BEN이 포함된 WBC-2, WBC-3 및 WBC-4는 전단력에 따라 요변성이 나타남으로서 WBC의 저장안정성이 우수하였다. 자동산화형 WBC의 건조성은 건조제가 Mn/Zn/Ba=1/2/3의 비로 혼합되었을 때, 6$0^{\circ}C$에서 5초로서 최대치를 나타내었다. 또한 BEN이 포함된 WBC 필름의 초기분해온도와 투명성은 시판 WBC(MC-21W)의 필름보다 32.2~54.7$^{\circ}C$와 5.1~8.6%의 범위로 증가하였고, WBC 필름의 내수성은 MC-21W

• 한국식품저장유통학회지
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• 제31권3호
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• pp.452-461
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• 2024

본 연구를 통해 적하수오(Polygonum multiflorum) 에탄올 추출물이 갖는 in vitro 항산화 활성 및 뇌 신경세포 보호 효과를 확인하고자 하였다. 적하수오 0%, 20%, 40%, 60%, 80% 및 95% 에탄올 추출물 중 40% 에탄올 추출물이 다른 추출물에 비해 상대적으로 많은 총페놀성 화합물 및 총플라보노이드 함량을 나타냈으며, 적하수오 40% 에탄올 추출물은 우수한 ABTS 라디칼 소거 활성과 MDA 생성 억제 효과를 나타내었다. 특히, 40% 에탄올 추출물은 높은 α-glucosidase 및 acetylcholinesterase (AChE) 억제 활성을 나타내었다. 또한, 적하수오 40% 에탄올 추출물은 H₂O₂ 유도 HT22와 SK-N-MC 세포에서 세포 생존율을 증가시키고 세포 내 산화적 스트레스를 감소시킴으로써 효과적인 세포 보호 효과를 나타냈다. 마지막으로, HPLC 분석결과 적하수오 40% 에탄올 추출물의 주요 생리활성 물질은 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside(TSG)로 확인되었다. 따라서, 본 연구에서 나타난 적하수오의 항산화 활성 및 뇌 신경세포 보호 효과는 TSG를 포함한 다양한 생리활성물질에서 기인한 것으로 판단되며, 건강기능식품에 소재로서의 활용 가능성이 기대된다.

• Natural Product Sciences
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• 제11권3호
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• pp.139-144
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• 2005

Bioflavone quercetin is believed to play an important role preventing bone loss by affecting osteoclastogenesis and regulating many systemic and local factors including hormones and cytokines. This study examined how quercetin acts on tumor necrosis factor-alpha ($TNF-{\alpha}$)-mediated apoptosis in MC3T3-E1 osteoblastic cells. Apoptosis assays revealed the dose-dependent acceleration of quercetin on $TNF-{\alpha}-induced$ apoptosis in MC3T3-E1 cells, which was demonstrated by the increased number of positively stained cells in the trypan blue staining and TUNEL assay, and the migration of many cells to the $sub-G_0/G_1$ phase in flow cytometric analysis. In particular, quercetin treatment alone increased the expression of p53 and p21 proteins in the cells. Consequently, this study showed that quercetin accelerates the $TNF-{\alpha}-induced$ apoptosis in MC3T3-E1 osteoblastic cells.

• 대한전자공학회논문지
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• 제27권3호
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• pp.21-30
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• 1990

본 논문은 MC-CVQ(motion compensated and classified vector quantization) 알고리듬의 하드웨어 실현에 관한 것으로, $128{\times}128$화소로 구성된 흑백영상을 64Kbps채널로 1초에 약 10장의 화면을 전송할 수 있는 화면간 부호화장치의 제작에 대하여 설명하였다. 위의 조건하에서 보호화를 수행하기 위하여, 시스템을 MC부, CVQ부, 보호화부로 구분하여 마이크로프로그램 제어에 의한 멀티프로세서 구조로 구성하였다. 그리고 MC부와 CVQ부에서 최소 거리 오차를 효율적으로 계산하기 위하여 연산부에는 3~단 파이프라인 구조를 채택하였다. 시스템 제작 후 성능을 평가한 결과, 본 시스템의 화면전송율은 영상신호의 상대적 이동량에 따라 1초에 6~15장 정도임을 확인하였다.

• 한국재료학회지
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• 제11권6호
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• pp.472-476
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• 2001

광학 및 주사전자현미경을 사용하여 X%C-5%Cr-5%V-5%Mo-5%W-5%Co 조성을 가진 다합금계백주철에서 정출되는 탄화물의 종류 및 형태를 3차원적으로 관찰하였는 바 MC, M$_2$C 및 M$_{7}$C$_{3}$의 3종류의 탄화물이 정출되었다. MC탄화물은 꽃잎, 구상 그리고 산호초형태의 3종류, M$_2$C탄화물은 층상 및 판상의 2종류, M$_{7}$C$_{3}$7탄화물은 고크롬백주철에서 관찰되는 막대형태의 한 종류만 관찰되었다. 첨가한 합금원소중 Co는 기지조직에만 고용되었기 때문에 탄화물의 현상에는 영향을 미치지 않았다.않았다.

• Journal of Microbiology and Biotechnology
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• 제28권1호
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• pp.40-49
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• 2018

We evaluated the antioxidant activity and neuronal cell-protective effect of fucoidan extract from Ecklonia cava (FEC) on hydrogen peroxide ($H_2O_2$)-induced cytotoxicity in PC-12 and MC-IXC cells to assess its protective effect against oxidative stress. Antioxidant activities were examined using the ABTS radical scavenging activity and malondialdehyde-inhibitory effect, and the results showed that FEC had significant antioxidant activity. Intracellular ROS contents and neuronal cell viability were investigated using the DCF-DA assay and MTT reduction assay. FEC also showed remarkable neuronal cell-protective effect compared with vitamin C as a positive control for both $H_2O_2$-treated PC-12 and MC-IXC cells. Based on the neuronal cell-protective effects, mitochondrial function was analyzed in PC-12 cells, and FEC significantly restored mitochondrial damage by increasing the mitochondrial membrane potential (${\Delta}{\Psi}m$) and ATP levels and regulating mitochondrial-mediated proteins (p-AMPK and BAX). Finally, the inhibitory effects against acetylcholinesterase (AChE), which is a critical hydrolyzing enzyme of the neurotransmitter acetylcholine in the cholinergic system, were investigated ($IC_{50}$ value = 1.3 mg/ml) and showed a mixed (competitive and noncompetitive) pattern of inhibition. Our findings suggest that FEC may be used as a potential material for alleviating oxidative stress-induced neuronal damage by regulating mitochondrial function and AChE inhibition.

• Animal Bioscience
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• 제36권1호
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• pp.132-143
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• 2023

Objective: The aim was to study the influence of cooling milk at 9℃ at the farm versus keeping it at 20℃ on Parmigiano Reggiano cheese lipolysis. Methods: A total of six cheesemaking trials (3 in winter and 3 in summer) were performed. In each trial, milk was divided continuously into two identical aliquots, one of which was kept at 9℃ (MC9) and the other at 20℃ (MC20). For each trial and milk temperature, vat milk (V-milk) and the resulting 21 month ripened cheese were analysed. Results: Fat and dry matter and fat/casein ratio were lower in MC9 V-milk (p≤0.05) than in MC20. Total bacteria, mesophilic lactic acid and psychrotrophic and lipolytic bacteria showed significant differences (p≤0.05) between the two V-milks. Regarding cheese, fat content resulted lower and crude protein higher (p≤0.05) both in outer (OZ) and in inner zone (IZ) of the MC9 cheese wheels. Concerning total fatty acids, the MC9 OZ had a lower concentration of butyric, capric (p≤0.05) and medium chain fatty acids (p≤0.05), while the MC9 IZ had lower content of butyric (p≤0.05), caproic (p≤0.01) and short chain fatty acids (p≤0.05). The levels of short chain and medium chain free fatty acids (p≤0.05) were lower and that of long chain fatty acids (p≤0.05) was higher in MC9 OZ cheese. The principal component analysis of total and free fatty acids resulted in a clear separation among samples by seasons, whereas slight differences were observed between the two different milk temperatures. Conclusion: Storing milk at 9℃ at the herd affects the chemical composition of Parmigiano Reggiano, with repercussion on lipolysis. However, the changes are not very relevant, and since the cheese can present a high variability among the different cheese factories, such changes should be considered within the "normal variations" of Parmigiano Reggiano chemical characteristics.

• Imaging Science in Dentistry
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• 제34권2호
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• pp.99-106
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• 2004

Purpose: To investigate the effects of irradiation on the phenotypic expression of the MC3T3-El osteoblastic cell line, especially on the osteonectin and bone sialoprotein. Materials and Methods: Cells were irradiated with a single dose of 0.5, 1, 4 and 8 Gy at a dose rate of 5.38 Gy/min using Cs-I37 irradiator. After specimens were harvested, total RNA was extracted on the 3rd, 7th, 14th, 21st day after irradiation. The total RNA was reverse-transcribed and the resulting cDNAs were subjected to amplification by PCR with a pair of primers. Results: The irradiated cells showed a dose-dependent increase in osteonectin mRNA expression when compared with the unirradiated control group. The irradiated cells showed no difference in bone sialoprotein mRNA expression when compared with the unirradiated control group. In accordance with the duration of culture period after irradiation, the level of osteonectin mRNA expression showed no difference, but it increased a little at the 21st day in the 4 and 8 Gy exposure groups. In the case of bone sialoprotein, however, the level of mRNA expression increased significantly at the 3rd and 7th day after irradiation, but it showed no difference at the 14th and 21st day when compared with the control group. Conclusion: These results showed that each single dose of 0.5, 1, 4 and 8 Gy influenced the mRNA expression of osteonectin and bone sialoprotein at the calcification stage of osteoblastic cells, suggesting that single dose of irradiation affected the osteoblastic bone formation at the cell level.

• 원자력산업
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• 제38권5호
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• pp.21-26
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• 2018

고준위 방사성폐기물 처분사업은 미 의회 내에서도 골치 아프고 민감한 문제로서 지난 몇 년간 아무 해결책 없이 손을 놓고 있는 상태이다. 교착 상태에 빠져 있는 이 문제는 올해 치러지는 선거가 끝난 후에나 해결책이 나올 수 있을 것으로 전망되고 있다.

• 충청수학회지
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• 제13권1호
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• pp.21-26
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• 2000

In this paper, we define the strong Perron integral and study the relationship between the integrals of strong Perron and McShane.