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Zinc stearate의 첨가가 $UO_{2}$분말의 겉보기밀도, 혼합 및 성형에 미치는 효과
나상호,김시형,이영우,양명승,손동성,Na, Sang-Ho,Kim, Si-Hyeong,Lee, Yeong-U,Yang, Myeong-Seung,Son, Dong-Seong 한국재료학회 1995 한국재료학회지 Vol.5 No.4
윤활제인 zinc stearate의 첨가량 (0~4wt%)을 변화시켜 U$O_{2}$분말의 겉보기밀도, 성형시의 분말입자간 마찰과 입자/다이벽 마찰간의 상관관계를 조사하였다. 소량의 윤활제 첨가시에는 U$O_{2}$분말입자간 박막의 윤활제 도포층이 형성되어 겉보기밀도가 증가한 반면 다량의 윤활제를 첨가한 경우에는 U$O_{2}$ 분말입자에 두꺼운 윤활제 도포층이 형성되고 미혼합된 윤활제가 존재하여 겉보기밀도는 감소하는 경향을 보였다. 윤활제를 첨가혼합한 상태에서 다이벽 윤활도포 유무에 따라 구한 U$O_{2}$ 성형체의 성형압력/성형밀도 자료로부터 분말입자간 마찰, 입자/다이벽 마찰 그리고 성형시 lubrication/inhibition등의 상대적 중요성을 조사하였다. 입자/다이벽 마찰에 의한 압력손실은 입자간 마찰에 의한 압력손실보다 크게 나타났다. 입자/다이벽 마찰에 의한 압력손실은 다이벽 윤활제 도포에 의해 최소화될 수 있지만 상대적으로 바람직하지 않은 성형시의 inhibition이 야기되는 것으로 나타났다.
Structural Feature of Rhamnogalacturonan-I Type Polysaccharide Purified from Radish Leaves
Seung-U Son,Sue Jung Lee,Kwang-Soon Shin 한국식품영양과학회 2021 한국식품영양과학회 학술대회발표집 Vol.2021 No.10
To elucidate structural feature of the immuno-stimulating polysaccharide, REP-I fraction was purified from radish leaves. And then the primary structure of REP-I was examined after seqeuntial hydrolysis. REP-I was consisted of 9 different monosaccharides which included main sugars such as GalA, Gal, Ara and Rha. Methylation analysis indicated that REP-I contained 13 different glycosyl linkages such as 4-linked GalpA, 2,4-linked Rhap, 4-linked Galp, 5-linked Araf and 3,6-linked Galp, being characteristics of RG-I. To determine the micro-structure, sequential degradation using four different linkage-specific glycosylases and one β-elimination was carried out, and then their fragments was analyzed by sugar composition, methylation and MS/MS spectroscopy. As a results, we assumed that the immuno-stimulating activity of REP-I may be due to a structure of RG-I composed of a main chain with repeating linkage unit [→2)-Rhap-(1→4)-GalpA-(1→] and three groups of side chains such as α(1→5)arabinan, β(1→4)galactan and arabino-β-3,6-galactan, which were branched at the C4 position of Rha residues in the main chain of REP-I.
Seung-U Son,Sue Jung Lee,Ho-Young Park,Kwang-Soon Shin 한국식품영양과학회 2021 한국식품영양과학회 학술대회발표집 Vol.2021 No.10
The crude polysaccharide (RWP) was isolated from radish leaves by hot water extraction and ethanol precipitation, and its immuno-stimulating and anti-metastatic activities were investigated. From the sugar composition analysis, RWP was mainly composed of galacturonic acid (69.9%), galactose (9.9%), arabinose (5.8%) and rhamnose (2.5%), being characteristic sugars of pectic polysaccharide. Peritoneal macrophages stimulated with RWP significantly augmented the production of various cytokines such as interleukin (IL)-6, IL-12 and tumor necrosis factor-α. In an assay for natural killer (NK) cell activity, both i.v. and oral administration of RWP significantly enhanced NK cells cytotoxicity against YAC-1 lymphoma. In an experiment on lung metastasis of Colon26-M3.1 carcinoma, prophylactic i.v. and oral administration of RWP inhibited metastasis by 77.2% and 55.0%, respectively, at a dose of 1,000 μg/mouse. Furthermore, pretreatment with anti-asialo GM1 for NK cells-depletion partly suppressed the inhibitory effect of RWP on lung metastasis. Above results suggest that RWP has potent antimetastatic activity, and this effect is related to the activation of various immune factors.