• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.1
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• pp.63-69
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• 2011

To characterize the polysaccharides which exist as soluble forms in Korean traditional alcoholic beverages, the polysaccharides were isolated from Korean pear wine and their anti-complementary activities were examined. The main polysaccharide, PW-1 was purified to homogeneity from the crude polysaccharide (PW-0) in pear wine by size exclusion chromatography using Sephadex G-75. Molecular mass of PW-1 was estimated to be 150 kDa and it contained significant proportion of mannose (81.8%) and 5 different minor component sugars such as arabinose (1.2%), galactose (2.7%), glucose (8.5%), galacturonic acid (5.3%) and glucuronic acid (0.5%). These analyses indicated that the main polysaccharide in pear wine was mainly present as a mannan which had originated from the cell walls of fermenting yeasts. On the other hand, PW-1 showed potent anti-complementary activity in a dose-dependent fashion. Identification of C3 activation products by the crossed immunoelectrophoresis using anti-human C3 and anti-complementary activity of PW-1 in $Ca^{++}$-free condition suggested complement activations by PW-1 from Korean pear wine occur via both classical and alternative pathways.

• Journal of Life Science
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• v.24 no.4
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• pp.437-446
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• 2014

Problems appear when triptans are taken orally. For example, the bioavailability of triptan is reduced by the digestive system, and the drug level in the blood reduces rapidly over time; there is also a possibility of gastrointestinal disorder. To improve side effects, a transdermal patch has been prepared in hydrogel form. The polymer matrix that makes up the hydrogel uses PVA; PEG is used as an additive to induce inter/intra hydrogen bonding of the PVA and almotriptan drug is added. In addition, to accelerate micro-phase separation between PVA chains, liquid nitrogen is used. In FT-IR analysis, the absorption bands of PVA, PEG, and almotriptan were found. The degree of crystallinity, the water uptake ability and tensile strength were increased with increasing PEG content. In drug release tests, the amount of drug released increased depending on the PEG content. In this study, hydrogels with 10 wt% PEG showed better performance in drug release. Approximately 60% of the total drug amount was released in 2 hr, and the drug continued to release for 1 day. Thus, the prepared hydrogel patch is suitable as a transdermal formulation for the second dose administration of triptans to patients who require recurrent migraine treatment within 24 hr after the first administration.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.632-637
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• 2001

Components of polysaccharides isolated from ascidian tunic were measuerd by gel filtration, electrophoresis and chemical analyses. The sulfated polysaccharides consisted in sulfate, protein, uronic acid and amino sugars. Hexosamines were composed of arabinose, xylose, glucose, galactose, glucuronic acid, N-acetylgalactosamine and N-acetylglucosamine by gas chromatography analysis. The galactose was predominant hexose after autoclave and nutrase digestion followed by DEAE-cellulose ion exchange chromatography and gel-permeation chromatography on Sephadex G-100 and G-25. FT-IR spectra of isolated polysaccharides from ascidian tunic and standard chondroitin sulfates have similar functional groups of the type of vibration and frequency. Molecular weight of isolated polysaccharides by autoclave represented more than 40 kDa by polyacrylamide gel electrophoresis. But the neutrase treatment group divided into three band. The highest molecular band group was shown more than 100 kDa, and the two low molecular band group were shown about 22 kDa and 5 kDa, respectively, compare to standard materials.

• Korean Journal of Materials Research
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• v.11 no.2
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• pp.94-103
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• 2001

SiO$_2$ and PDMS/SiO$_2$ xerogels which are derived PDMS into TEOS have been synthesized by sol-gel process and controlled pore size and distribution through 2 step acid/base catalyzed processes using HCI and NH$_4$OH as a catalyst. In HCl catalyzed SiO$_2$ and PDMS/SiO$_2$ xerogels, pH and gellation time of xerogel were 2.3~2.5 and 12~13 days, respectively, and the shape of xerogel was identified to pellet type and column type. Under acidic condition of final reaction solution, the hydrolysis rate is accelerating, resulting in long gel times. The shape of xerogel is pellet type. In contrast, under less acidic condition, the condensation rate is accelerating, resulting in shorter gel times and the shape of xerogel is column type. The surface area and average Pore size were changed 400$\rightarrow$600($\m^2$/g) and 15$\rightarrow$28$\AA$, respectively, depending to the increase of the mole ratio of HCl/NH$_4$OH, and represented uniform pore size distribution. It is that all the alkoxide groups are hydrolyzed by HCl after the first step and the condensation rate is enhanced by NH$_4$OH. The regular backbone structures of silica are formed at low temperature and the uniform pores are produced by heat treatment.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.883-891
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• 2017

For the preferential oxidation of CO contained in the fuel of polymer electrolyte membrane fuel cell (PEMFC), CuO-$CeO_2$ mixed oxide catalysts were prepared by the sol-gel and co-precipitation methods to replace noble metal catalysts. In the catalyst preparation by the sol-gel method, Cu/Ce ratio and hydrolysis ratio were changed. The catalytic activity of the prepared catalysts was compared with the catalytic activity of the noble metal catalyst($Pt/{\gamma}-Al_2O_3$). Among the catalysts prepared with different Cu/Ce ratios, the catalyst whose Cu/Ce ratio was 4:16 showed the highest CO conversion (90%) and selectivity (60%) at $150^{\circ}C$. As the hydrolysis ratio was increased in the catalyst preparation, surface area increased, and catalytic activity also increased. The highest CO conversions with the CuO-$CeO_2$ mixed oxide catalyst prepared by the co-precipitation method and the noble metal catalyst (1wt% $Pt/{\gamma}-Al_2O_3$) were 82 and 81% at $150^{\circ}C$, respectively, whereas the highest CO conversion with the CuO-$CeO_2$ mixed oxide catalyst prepared by the sol-gel method was 90% at the same temperature. This indicates that the catalyst prepared by the sol-gel method shows higher catalytic activity than the catalysts prepared by the co-precipitation method and the noble metal catalyst. From the CO-TPD experiment, it was found that the catalyst having CO desorption peak at a lower temperature ($140^{\circ}C$) revealed higher catalytic activity.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.475-479
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• 2011

Chitosan is a natural polymer that has many physicochemical(polycationic, reactive OH and $NH_2$ groups) and biological(bioactive, biocompatible, and biodegradable) properties. In this study, chitosan nanoparticles were prepared using poly-${\gamma}$-glutamic acid(${\gamma}$-PGA) as gelling agent. Nanoparticles were formed by ionic interaction between carboxylic groups in ${\gamma}$-PGA and amino groups in chitosan. Chitosan(0.1~1 g) was dissolved in 100 ml of acetic acid (1% v/v) at room temperature and stirred overnight to ensure a complete solubility. An amount of 0.1 g of ${\gamma}$-PGA was dissolved in 90 ml of distilled water at room temperature. Chitosan solution was dropped through needle into beaker containing ${\gamma}$-PGA solution under gentle stirring at room temperature. The average particle sizes were in the range of 80~300 nm. The prepared chitosan/${\gamma}$-PGA nanoparticles were used to examine their removal of several heavy metal ions($Cd^{2+}$, $Pb^{2+}$, $Zn^{2+}$, $Cu^{2+}$, and $Ni^{2+}$) as adsorbents in aqueous solution. The heavy metal removal capacity of the nanoparticles was in the order of $Cu^{2+}$ > $Pb^{2+}$ > $Cd^{2+}$ > $Ni^{2+}$ > $Zn^{2+}$.

• Polymer(Korea)
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• v.33 no.6
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• pp.551-554
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• 2009

Poly (vinyl alcohol) (PVA) and carboxymethyl cellulose (CMC) have received increasing attention in biomedical and biochemical applications because of their properties such as being water-soluble and biocompatible. In this study, a PVA/CMC hydrogel applicable to artificial cartilage was prepared by a freezing-thawing technique and a gamma-ray irradiation. The solid concentration of PVA was 7 wt% and the concentration of CMC was 4 wt%. The freezing/thawing process was repeated twice and the dose of gamma-ray irradiated was 30 kGy. Results of gelation before and after gamma-ray irradiation were similar, but the swelling degree decreased and compressive strength increased. The cytotoxicity was investigated with CCK-8 assay.

• Polymer(Korea)
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• v.33 no.2
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• pp.158-163
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• 2009

In this study, we synthesized a series of dendritic polystyrene-b-linear poly (t-butyl acrylate) copolymers with well-defined molecular architectures. The hydroxyl group located at the focal point of the second generation dendron bearing polystyrene ($M_n$ = 1000 g/mol) peripheries was converted into amine group via the following stepwise reactions: 1) tosylatoin, 2) azidation, and 3) reduction. On the other hand, the linear poly (t-butyl acrylate)s were prepared by an atom transfer radical polymerization (ATRP) of t-butyl acrylate where benzyl 2-bromopropanoate and Cu(I)Br/PMDETA were used as initiator and catalyst, respectively. To convert the end group of prepared poly (t-butyl acrylate) s into carboxylic acid, a debenzylation was performed using Pd/C catalyst under $H_2$ atmosphere. In the final step, dendritic-linear block copolymers were obtained through a simple amide coupling reaction mediated by 4-(dimethylamino) pyridine(DMAP) and N,N'-diisopropylcarbodiimide(DIPC). The resulting diblock copolymers were shown to have well-defined molecular weights and narrow molecular weight distributions as supported by $^1H$-NMR spectroscopy and gel permeation chromatography(GPC).

• Journal of Soil and Groundwater Environment
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• v.8 no.2
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• pp.62-69
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• 2003

The aim of research is the evaluation of the $Cr^{6+}$ emission features of the liquid injection through emission experiments in varying conditions, based on a field-mixing ratio. The results showed that the content of $Cr^{6+}$ content in cement measured had an Ordinary Potland Cement (OPC) of 25.3 mg/kg, which constitute the largest portion among the other materials. Likewise, the emission experiment of homo-gel and sand-gel generally satisfied the standard of KSLT (Korea Standard Leaching Test) in waste of 1.5 mg/L, but in case of the standard of KSLT in soil the emission of OPC $Cr^{6+}$ of 4.85 mg/kg. These conditions is a little exceeded the criteria in the ‘Ga’ area in terms of Korea Soil Environmental Preservation Law. In addition, results generated by the mock-up injection facilities revealed that $Cr^{6+}$ emission increased as Water/Cement and injection pressure increased. At injection pressure higher than 4 kg/㎤, $Cr^{6+}$ emission exceeded the water preservation standard of 0.5 mg/L. Similarly, a pattern experiment of C $r^{6+}$ emission according to pH was conducted, in order to evaluate the $Cr^{6+}$ emission features of grout materials in leachate below pH 5 such as pH 4 acid rain or landfill. Results show that $Cr^{6+}$ emission dramatically increased in high acidic or basic state. It indicates that $Cr^{6+}$ emission will probably increase in an environment where grout materials are injected. On the other hand, concentration of leachate was determined in areas where grout materials are used. The results show that the concentration of emission in an ultra purity condition does not manifest intensity, and is affected in the OPC>MC>SC order. It means that the pollutants or $Cr^{6+}$ emission increases with decreasing concentration. As such, $Cr^{6+}$ emission will probably exceed the countermeasure criteria according to the types of gout materials. Similarly, high pressure or injection will cause increased $Cr^{6+}$ emission. Therefore, the selection of materials or mixing ratio should be considered in general as well as according to specific industries, based on the strength and pH of $Cr^{6+}$ emission.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.1-8
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• 1997

A complement system-activating (anti-complementary) polysaccharide was purified from the hot water extract of young stems of Cinnamomum cassia Blume. Crude polysaccharide fraction (CC-1) was prepared from the hot water extract of the young stems followed by methanol-reflux, precipitation with ethanol, dialysis, and lyophilization. The anti-complementary activity of CC-1 was decreased greatly by periodate oxidation, but was not changed by pronase digestion. These suggest that carbohydrate moiety may be related to the activation of complement system. According to its ionic strength CC-1 was fractionated first using cetavlon to give 4 fractions, CC-2, 3, 4 and 5. Among them CC-2 fraction was found to retain the highest activity and yield. CC-2 was separated to an unabsorbed neutral sugar portion (CC-2-I) and seven absorbed acidic sugar fractions $(CC-2-II{\rightarrow}CC-2-VIII)$ on DEAE-Toyopearl 650C (Cl-). CC-2-III showing higher anti-complementary activity and yield than those of other fractions, was further purified on the gel permeation of Sephadex G-100 and Sepharose CL-6B to CC-2-IIIa-3. CC-2-IIIa-3 was determined to have a homogeneity hy GPC (Sepharose CL-6B) and HPLC. Gel chromatography using standard dextrans gave a value of $2.4{\times}10^5$ for the molecular weight. The purified polysaccharide, CC-2-IIIa-3 consisted of arabinose, xylose, glucose, galactose, galacturonic acid and glucuronic acid in a molar ratio of 5.56 : 3.77 : 1.87 : 1.00 : 5.12 : 3.13 and contained no nitrogen.