• Bulletin of the Korean Chemical Society
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• v.28 no.2
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• pp.229-234
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• 2007

One new compound, 3,7,11,19,23,27-hexamethyl-15-hydroxymethylene-n-octacos-5,8,20-triene-10β,18α- diol-10β-D-glucopyranoside (1), along with the three known compounds, 3-epibetulinic acid (2), n-pentadecanyl octa-dec-19-en-oate (3) and β-sitosterol (4) were isolated from the methanolic extract of the cultured Catharanthus roseus hairy roots. The structures of the one new and three known compounds were elucidated using one- and two-dimensional NMR in combination with IR, EI/MS, FAB/MS. To the best of our knowledge, 3,7,11,19,23,27-hexamethyl-15-hydroxymethylene-n-octacos-5,8,20-triene-10β,18α-diol-10β-D-glucopyranoside, 3-epibetulinic acid and n-pentadecanyl octa-dec-19-en-oate were identified for the first time from the hairy roots of C. roseus.

• Polymer(Korea)
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• v.29 no.2
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• pp.140-145
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• 2005

Effects of the polyol type and the hard segment content of thermoplastic polyurethane (TPU) on the crystallization of hard segments in TPUs were studied employing differential scanning calorimetry. Diols used for the preparation of TPUs were poly(tetramethylene ether glycol) (PTMEG), poly(propylene glycol) (PPG), polycaprolactone (PCL), poly(butylene adipate) (PBA) the molecular weights of which were 2000 and the hard segments contents of TPUs were $35\~44\;wt\%$. We found that crystallization of hard segments in TPUs were observed at higher temperatures and became faster with increasing hard segment contents of TPUs. The crystallization rate of TPU was also affected by the types of polyols used for the preparation of TPUs. It is postulated that lower miscibility of soft segments and hard segments results in higher crystallization rate and increase of cooling crystallization temperatures due to better hydrogen bending between hard segments in melts.

• Polymer(Korea)
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• v.34 no.6
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• pp.507-510
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• 2010

Poly(cyclohexane carbonate) diol was synthesized by the alternating copolymerization of cyclohexene oxide and $CO_2$ over Cr based transition metal catalysts. The prepared PCCD was applied as a precursor for the preparation of waterborne polyurethane (PUD) in order to investigate an application field of carbon dioxide-based polycarbonate. The scratch resistance and thermal properties of PUDs, which was prepared with two kinds of polymeric diols (PCD and PCCD) were investigated. The scratch resistance and thermal decomposition temperature of PUD film prepared with PCCD is worse than those prepared with PCD, poly(hexamethylene carbonate) glycol. While, glass transition temperature of PUD film prepared with PCCD was higher than that prepared with PCD. It might be due to the rigid cyclohexane structure in the PCCD.

• Proceedings of the Ginseng society Conference
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• 1993.09a
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• pp.132-137
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• 1993

Several Prosapogenins and sapogenins obtained by acid hydrolysis or alkaline cleavage of Korean red ginseng saponins were separated and identified by spectral and physical methods. Some of these degradation products showed the cytotoxic activities against various cancer cell lines, that is, A549, SK - OV - 3, L121O, P388 and K562. The significant difference of activity between stereoisooers was not approved and the activity was inversely proportional to the number of sugars binding to sapogenins. It was clear that diol type prosapogenins and sapogenins were more cytotoxic than triol type ones.

• Journal of Ginseng Research
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• v.12 no.1
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• pp.63-67
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• 1988

To investigate the effect of ginseng saponin fractions (total saponin, diol saponin and triol saponin) on the antibody production and on the recovery of immunosuppression in mouse, chick ${\gamma}$-globulin was used as immunogen and CY(cyclophosphamide) as immunosuppressive drug. The effect of ginseng saponin fractions on the production of total serum protein was investigated also. Circulating antibody was measured with ELISA method. Total saponin, dial saponin and triol saponin resulted 4 times higher titer values compared to control group in the production of antibody but resulted no effect on the recovery of immunosuppression induced by CY. From the above results ginseng saponin fractions are believed to effect on intact immune system and to promote antibody production by helping the cooperations among lymphocytes or the growth of lymphocytes. And the increase of total serum protein has no direct relations with the increase of circulatory antibody.

• Polymer(Korea)
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• v.29 no.1
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• pp.59-63
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• 2005

Kinetic study of a reaction between poly(caprolactone diol) and aliphatic isocyanate was investigated by FTIR spectroscopy. The reaction rate was obtained from analyzing the absorbance change of NCO peak (2265 $cm^{-1}$) in series IR spectra. In the results, the overall reaction between PCL and isocyanate conformed to the simple second-order law, and the rate constant increases with increasing reaction temperature. The activation energies obtained from the evaluation of kinetic data were 25.4∼30.9 kJ/mol for hexamethylene diisocyanate and 16.8∼22.1 kJ/mol for cyclohexylmethane diisocyanate, respectively.

• Polymer(Korea)
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• v.33 no.2
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• pp.175-182
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• 2009

Waterborne polyurethanes (WPUs) based on isophorone diisocyanate and mixed polyols of poly(tetramethylene glycol) (PTMG)/polycarbonate diol (PCD) were synthesized. The variation of mechanical and dyeing properties and alkali resistance of the WPU films were analyzed according to the polycarbonate (PC) content. The tensile strength of the films increased and the elongation at break decreased with the PC content in the WPU film. The incorporation of PC component in the WPU film did not affect the alkaline hydrolysis behavior. The synthesized WPU solutions were used as impregnating resins for the production of PET artificial leathers. The prepared WPU resins showed the good color fastness to washing, rubbing, and light of the artificial leather fabrics. The improvement of the properties became greater with the PC content in the WPU resin.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2003.05a
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• pp.53-53
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• 2003

• YAKHAK HOEJI
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• v.37 no.5
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• pp.437-441
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• 1993

The efficient synthesis of protected $\beta$-hydroxyhomoserine, which is an important intermediate in the synthesis of Mugineic acid, from cis-2-butene-1, 4-diol as a starting material through 12 steps will be reported herein.

• Korean Journal of Plant Resources
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• v.4 no.2
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• pp.35-38
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• 1991

Two new diterpene compounds have been isolate from the roots of Eragrostis ferruginea (Thunb.) Beauv. and their structures were elucidated as isopimara-9(11), 15-0ien-l9-ol-3-one and cassa-13(14), 15-diene-3, 12-dione by various spectroscopic me-thods. We have also isolated a known diterpene diol isopimara-9(11). 15-diene-3$\beta$, 19-dio1.