• Korean Journal of Pharmacognosy
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• v.25 no.1
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• pp.41-46
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• 1994

The ether, ethylacetate and n-butanol soluble fractions from the roots of Scutellaria baicalensis showed a significant inhibition of lens aldose reductase (AR) activity in vitro. During systematic fractionation of the active fractions, 7 flavonoids were isolated and compared their inhibitory activities against rat AR using DL-glyceraldehyde as a substrate, among which baicalin (VII) was found to exhibit the most potent inhibitory activity. Baicalin (VII) and wogonin-7-O-glucuronide (VI), with repeated treatments (30 mg/kg/day, i.p.) throughout the experimental periods caused a significant suppression of cataract formation induced by galactose (40 g/kg/day) as well as the decrease of galactitol accumulation in the rat lens. The flavonoids also exhibited a significant inhibition of sorbitol accumulation in the lenses of diabetic rats induced by streptozotocin (STZ).

• 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.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.738-741
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• 2001

We carried out aminolyses of various rigid polyurethane foams (PUFs) using diethylene triamine and studied application of the aminolysis products as hardners of epoxy resins. Diglycidyl ether of bisphenol A was used for the study on the curing behavior of epoxy resin with the aminolysis product employing differential scanning calorimeter. Curing reaction of the epoxy resin is generally known to be autocatalytic second order reaction. We found that the curing reaction of the epoxy resin with the aminolysis product of rigid PUF did not show autocatalytic characteristics but followed the n-th order kinetics. The activation energy of the curing reaction of the epoxy resin with the aminolysis product of rigid PUF made from sugar based polyol was slightly lower than that of the epoxy resin with aminolysis product of rigid with made from amine based polyol.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.184-184
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• 1998

Aldose reductase(AR), a rate-limiting enzyme in the polyol pathway, has been demonstrated to cause the intracellular accumulation of sorbitol or galactitol and hence to play key roles not only in the cataract formation in the lens but also in the pathogenesis of diabetic complications such as neuropathy, retinopathy and nephropathy, etc. In a series of investigations to evaluate potential AR inhibitors from medicinal plants, we have shown that some hot water extracts exhibited a significant inhibition of a significant inhibition of bovine lens AR in vitro. Among active plants, the roots of Angelica dahuria (Umbelliferae) were shown to have relatively potent AR inhibitory activity. Systematic fractionation of the ether soluble fraction monitored by bioassay led to isolation of two furanocoumarins, byakangelicin(I) and ter-O-methyl byakangelicin( II), were identified as potential AR inhibitors, their $IC_{50}$ values being 6.2 M and 2.8 M, respectively.

• Journal of the Korean Applied Science and Technology
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• v.36 no.2
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• pp.524-530
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• 2019

In this study, polyether polyol polypropylene glycol and isophorone diisocyanate (IPDI) were synthesized based on polyrupopylene mono methyl eher (PM) for the synthesis of water - soluble polyurethane for coating on leather skin layer. After synthesis of prepolymer, PM was added at $40^{\circ}C$ to 1M, 2M, 3M, and 4M to inhibit the viscosity rise, and neutralization reaction and chain extension reaction were carried out to prepare polyurethane samples. According to the measurement results of the tensile strength, elongation and adhesive strength of the prepared sample, the tensile strength was 2.109 kgf / mm2 for PM 1M, 1.721kgf / mm2 for 4M, elongation was 496% for PM 1M, 522% for 4M, adhesion was 1.114 kgf / cm for PM 1M and 0.99 kgf / cm for 4M.

• Elastomers and Composites
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• v.33 no.3
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• pp.177-184
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• 1998

Polyurethane(PU) prepolymers were synthesized from polytetramethylene ether glycol(PTMG), with 4,4'-diphenylmethane diisocyanate(MDI), toluene 2,4-diisocyanate (TDI) and isophoron diisocyanate(IPDI). After chain extention using n-methyl-diethanol amine(n-MDEA), aqueous polyurethane cationomers were prepared by addition of glycolic acid(GA) as a quaternizer. The effect of the content of chain extender and the degree of neutralization on the stability of emulsion, adhesive strength, viscosity, glass transition temperature and physical properties of emulsion cast film were investigated using UTM, viscometer and DSC.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.809-813
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• 1999

D phase emulsification has been developed and elucidated the emulsification mechanism by using phase diagrams. The process of D phase emulsification begins with the formation of isotropic surfactant solution, follows by formation of oil-in-surfactant (O/D) gel emulsion by dispersion of octamethylcyclotetra siloxane(OMCS) in the surfactant solution. Polyols were essential components for this experiments. To understand the function of polyols, the solution behaviors of nonionic surfactant/oil/water/polyol systems were investigated by the ternany phase diagrams of polyoxyethylene oleyl ether/OMCS/propylene glycol(PG) aqueous solutions. The solubility of oil in the isotropic surfactant phase was increased with the addition of PG. D phase emulsion was formed in the range of 70~90% of OMCS and 2.0~3.0 dyne/cm of interfacial tension and the structure was homogenious spherical and O/W type and its diameter was about $10{\mu}m$.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.149-162
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• 2003

Moisturizing the skin is one of the most important functions of skincare cosmetics, because water plays a significant role in keeping the skin healthy. There are various humectants including polyol (glycerin and 1,3-butylene glycol), water-soluble polymers, and botanical extracts. It is well known that the increased amount of polyol in lotion for obtaining high moisturizing effect gives a sticky feeling to the skin. Therefore, a few humectants that can give high moisturizing effect without a sticky feeling for lotion formula is available. On the other hand, oil-based lipstick is well known to have a difficulty to contain a large amount of hydrophilic humectants, because the humectants is unable to be mixed well into oil-based lipsticks and give the lips a peculiar taste. There are newly developed humectants, polyoxyethylene/polyoxypropylene dimethyl ether (EPDME) that can solve these problems describable above. EPDME is a random copolymer of ethylene oxide and propylene oxide. EPDME gives a low sticky feeling with a high moisturizing effect when it is used in lotion. As a remarkable character, EPDME can show not only a preventing effect on rough and dry skin, but also a improving effect upon the use for 1-4 weeks. EPDME can show a synergistic effect with glycerin on preventing to rough and dry skin. Since EPDME can be dissolved in oil-based formulation and used as an ingredient of lipsticks, EPDME can give a moisturizing effect that allows lip to be healthy condition. EPDME can also give no peculiar taste even upon the use of a large amount. EPDME is a useful cosmetic ingredient that can show a good skin care effect in both water-based formula and oil-based formula. EPDME of which polarity can be controllable is expected to be used for various cosmetic applications in near future.

• Journal of the Korean Applied Science and Technology
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• v.14 no.3
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• pp.23-28
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• 1997

The phase diagram for the surfactant mixture system of N-dodecanocyl-N-methyl amido polyolcarboxyl alkyl ether(DGC)/N-dodecanocyl-N-alkyl glucamine(DG)/water was studied usingpolarized microscopy, differential scanning calorimetry(DSC) and rheological measurements respectively. Using polarized microscopy, the textures of liquid crystal phases obtained at various surfactantconcentrations were investigated as a function of surfactant concentration and temperature, and phasetransitions between anisotropic liquid crystal phases and isotropic liquid phase were examined usingDSC measurements. Viscoelastic properties of surfactant solutions determined between hexagonal andlamellar liquid crystal phase by rheological measurements were approximately consistent with the resultsobtained by polarized microscopy and DSC. In the study for the phase of DGC/DG(5:5 mol ratio)/water system. It could be found that the hexagonal liquid crystal phase appeared at 25${\sim}$60wt％ ofsurfactant, the cubic liquid crystal phase at 50${\sim}$65wt％ and the lamellar crystal phase at above 70wt％.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.26 no.1
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• pp.93-106
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• 2000

One phase liquid crystal formula was developed by using of nonionic surfactants, polyols, water and oils and its physical property was investigated. At the system oft to 1 ratio of POE octyldodecyl ether series, which have Y type (branch type) hydrophobic group, and POE glyceryl monostearate series, Y type hydrophilic group, it was examined that the formula at 7:3, 6:4, and 5:5 ratio of nonionic surfactant : polyols, shows L$\alpha$ , a pattern which is a typical characteristic of liquid crystal structure under the cross microscope polarized film. As results of L$\alpha$ phase diagram study, the formula which had high hydrophilic nonionic surfactant and the 7:3 ratio of nonionic surfactant : polyol appeared to increase the amount of oil containment and to be capable of the lamella formation. Besides it was examined that lamellar liquid crystal formula could contain about 25-40% water between lamella layers and it was transformed into w/o emulsion following as water content increased. When the lamella gel was applied into a human skin, it was investigated that it had effectiveness in increasing transepidermal water content of the skin.