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폴리(스타이렌-b-아이소부틸렌-b-스타이렌) 삼블록 공중합체 아이오노머의 기계적인 성질
나연화,김희석,김준섭,유지강,박기주,이영관 조선대학교 생산기술연구소 1998 生産技術硏究 Vol.20 No.2
The dynamic mechanical properties of poly(styrene-b-isobutylene-b-styrene) and its sulfonated ionomers were investigated. The triblock copolymer showed a tan δ peak at ca. -25℃, which is ascribed to the T_(g) of polyisobutylene blocks. The copolymer also showed a shoulder on a tan δ curve at ca. 50℃, which is probably associated with crystallization and/or melting of the crystalline polyisobutylene blocks. Above 100℃, the copolymer started to flow. In the cases of ionomers, well developed rubbery plateaus, extended to ca. 150-160℃, were seen in modulus-temperature plots. A tan δ peak for the T_(g) of the polyisobutylene blocks and a shoulder peak were also observed for the tetramethylammonia neutralized sulfonated ionomer. However, the shoulder peak became smaller and shifted to low temperatures, which implies that the ionic interactions in this system reduces the ability of crystallization or/and melting of the polyisobutylene blocks. For the K neutralized ionomer sample, only a tanδ peak for the T_(g) of the isobutylene blocks was seen. This different result in these two ionomers is believed to be due to the difference in the strength of ionic interactions.
스타이렌 아이오노머의 기계적인 성질에 미치는 혼합 양이온의 영향
김희석,나연화,이용혁,이법원,유지강,박기주,김준섭 조선대학교 생산기술연구소 1998 生産技術硏究 Vol.20 No.1
The styrene-co-methacrylate ionomers neutralized with Na +, Ba2 +, and mixed cation of both were prepared. The dynamic mechanical properties of two cation-containing ionomers were measured and compared to those of the ionomers neutralized with only one type of cations. We found that in the ionomers with one type of cations the difference in the type of cation does not change the glass transition temperatures. It was found, however, that the cluster Tg of the mixed cation ionomer is lower than that of the single cation ionomers. Thus it was postulated that in the two-cation system the two cations in a solution have sufficient dynamics to form new type of multiplet containing both cations, which may be slightly bigger than that found in the single cation multiplet. The mechanical properties also imply that the strength of ion interactions in the multiplets of the two cation ionomer is thought to be weaker than that of the one cation ionomers. These two effects are believed to contribute the lower in the cluster glass transition of mixed cation system.
에틸 아크릴레이트 아이오노머의 성질에 미치는 양이온 크기의 영향
조규성,나연화,김희석,김준섭,박기주 조선대학교 생산기술연구소 1999 生産技術硏究 Vol.21 No.1
The effects of the size of cations on the properties of polyfethyl acrylate-co-metal acrylate) ionomers containing 3.8 mol% of ionic moiety were investigated. It was found that with changing cations, matrix T_(g)s seem to remain constant; however, cluster T_(g)s increase with decreasing the size of cations. Since ion-hopping occurs at a cluster T_(g) and the electrostatic force of ion pairs decreases with the size of ions increasing, it was suggested that the effect of the size of cation on a cluster T_(g) is operative, but not on a matrix T_(g). It was also found that activation energies for a cluster T_(g) were decreased with decreasing the size of cations; which means that the activation energy values for a cluster T_(g) are not directly related to the cluster T_(g)s. In the present study, the highest value of a cluster T_(g) for the Li ionomer may be one of the reasons why the Li ionomer has the lowest value for an activation energy.
Nah Jin-Ju,Choi Seok,Kim Yoon-Hee,Kim Seok-Chang,Nam Ki-Yeul,Kim Jong-Keun,Nah Seung-Yeol The Korean Society of Ginseng 1999 Journal of Ginseng Research Vol.23 No.1
진세노사이드(ginseng total saponin)는 인삼의 주요 약리학적 성분이다. 본 연구는 척수강내로 투여된 진세노사이드가 캡사이신에 의하여 유도된 통증을 억제하는가를 연구하였다. 진세노사이드의 척수강내 전투여는 캡사이신에 의하여 유도되는 통증을 투여 용량에 의존적으로 억제하였다. 통증 억제 효과를 나타내는 $ED_{50}$은 43 ${mu}g/mouse$ 이었다. 흥분성 아미노산들도 척수 수준에서 통증전달에 포함되기 때문에 본 연구에서는 또한 진세노사이드가 흥분성 아미노산에 의하여 유도되는 아픈 행동(nociceptive behaviors)을 억제하는 가를 연구하였다. 진세노사이드와 NMDA를 같이 투여할 경우 NMDA를 단독 투여할 때 나타나는 아픈 행동을 억제하는 것으로 나타났다. 진세노사이드가 NMDA에 의하여 나타나는 아픈 행동을 억제하는 $ED_{50}$은 37 ${mu}g/mouse$ 이었다. 그러나 진세노사이드는 kainate투여에 의하여 나타나는 아픈 행동을 억제하지 않은 것으로 나타났다. 이러한 연구 결과들은 진세노사이드에 의한 항통증 효능중의 하나는 척수 수준에서 통증 전달 물질에 의하여 유도되는 통증 전달 정보의 선택적 억제에 의하여 이루어진다는 것을 보여준다. Ginseng total saponins (ginsenosides) are biologically active main ingredients of Panax ginseng. In present study, we have investigated whether pretreatment of ginsenosides inhibited capsaicin-induced pain at the spinal level, in the view that capsaicin causes substance P (SP) release from primary afferents. Ginsenosides relieved capsaicin-induced pain in a dose-dependent manner. The $ED_{50}$ of the effect was 43 (20-93, $95\%$ C.I.) ${\mu}g/mouse$. We investigated excitatory amino acids-induced nociceptive responses in mice, because these agents are also involved in nociceptive transmission in the spinal cord. Coadministration of ginsenosides with N-methyl-D-aspartate (NMDA) or kainate via i.t. inhibited NMDA- but not kainate-induced pain behaviors. The $ED_{50}$ for the inhibition of NMDA-induced pain by ginsenosides was 37 (21-66, $95\%$ C.I.) ${\mu}g/mouse$. These results suggest that the ginsenosides-induced antinociception results from blocking of pain transmitter-induced nociceptive information at the spinal level.
Sil-Select와 Percoll이 정충의 미세구조에 미치는 영향
김성훈(Sung Hoon Kim),김정훈(Chung Hoon Kim),박은주(Eun Ju Park),홍석호(Seok Ho Hong),나희영(Hee Young Nah),김정희(Jung Hee Kim),음현진(Hyun Jin Em),김숙희(Sook Hee Kim),채희동(Hee Dong Chae),강병문(Byung Moon Kang),허주령(Joo Ryung 대한산부인과학회 2000 Obstetrics & Gynecology Science Vol.43 No.7
Objective : We performed this study to evaluate the effects of Sil-Select and Percoll in sperm preparation. Methods : Semen samples of 22 patients with normal sperm parameters by WHO criteria were divided into two equal parts and prepared with Percoll and Sil-Select. After completion of semen preparation procedures with Percoll and Sil-Select, sperm concentration, motility and morphology using strict criteria were evaluated in each group and all semen samples were fixed and stained for transmission electron microscopy(TEM). Results : There were no significant diffrences in sperm concentration, percentage of motile spermatozoa and percentage of normal spermatozoa in morphology evaluation using strict criteria under light microscopy between Percoll and Sil-Select-treated groups. However, the percentage of normal shape and position of acrosome, and normal helix assembly of mitochondria under TEM were significantly higher in the Sil-Select-treated group compared to Percoll-treated group (p < 0.001, p < 0.001, p < 0.001). Conclusion : These data demonstrate that Sil-Select is less detrimental to the acrosome and mitochondria of spermatozoa in sperm preparation compared to Percoll.