• Asian-Australasian Journal of Animal Sciences
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• v.16 no.2
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• pp.269-276
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• 2003

We studied the gel properties of porcine collagen with microbial transglutaminase (MTGase) as a catalyst. A creep meter was used to measure the mechanical properties of gel. The results showed samples with high concentration of MTGase gelled faster than those with a low concentration of MTGase. The gel strength increased with incubation time and the peaks of breaking strength for 0.1, 0.2 and 0.5% MTGase were obtained at 40, 20 and 10 min incubation time, respectively. According to SDS-PAGE, the MTGase was successfully created a collagen polymer with an increase in molecular weight, whereas no change in formation was shown without MTGase. The sample with 0.5% MTGase began to polymerize after 10 or 20 min incubation at $50^{\circ}C$, and complete polymerization occurred after 40-60 min incubation. Scanning electron microscopic analysis revealed that the gel of porcine collagen in the presence of MTGase produced an extremely well cross-linked network. The differential scanning calorimetric analysis showed the peak thermal transition of porcine collagen gel was at $36^{\circ}C$, and that with MTGase no peak was detected during heating from 20 to $120^{\circ}C$. The melting point of porcine collagen gel could be controlled by MTGase concentration, incubation temperature and protein concentration. Knowledge of the structural and physicochemical properties of porcine collagen gel catalyzed with MTGase could facilitate their use in food products.

• Journal of Powder Materials
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• v.12 no.3
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• pp.220-224
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• 2005

Boehmite (AlOOH) powder with uniform pore size and high specific surface area were synthesized via sol-gel method using metal salts, $Al_2(SO_4)_3$ and $NaAlO_2$. During these synthetic process, the effects of the aging time were investigated to determine the optimal synthetic conditions of boehmite. X-ray diffraction, BET, Raman/IR, and scanning electron microscopy techniques were used for the characterization of the powder. Boehmite gel synthesized at the first stage of the experimental procedure transformed to crystalline boehmite phase after aging for 6 hours. The specific surface area of the crystalline boehmite showed a maximum value, $350m^2/g$, at aging time of 72 hours. The pore size of the boehmite increased with increasing aging time and the boehmite with average pore diameter of 3.6 nm was obtained at aging time of 96 hours.

• Journal of Pharmaceutical Investigation
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• v.24 no.1
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• pp.11-16
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• 1994

In order to reduce the systemic side effects and gastrointestinal irritation of ketoprofen after its oral administration, it was formulated as a 3% ketoprofen gel (ID-GEL) with Pluronic F-127. The pharmacokinetic characteristics of ID-GEL was evaluated following its transdermal application on the dorsal skin of rats at the dose of 9 mg/kg in reference to those of existing 3% ketoprofen gels. Even though the maximum concentration of 810 ng/ml was reached at 6 hrs postdose, the plasma concentration was kept almost constant until 24 hrs postdose, which suggested that ketoprofen was released continuously from the gel during this period. The bioavailability of ID-GEL was two times higher than those of existing 3% ketoprofen gels, based on the calculated area under the plasma concentration-time curves after the percutaneous administration.

• Journal of the Korean Ceramic Society
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• v.28 no.4
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• pp.324-328
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• 1991

Monolithic silica gel and glass were prepared from TMOS solution with high concentration of HCl. Appearance of the dried gels and gelation time varied with content of HCl and H2O were observed in the TMOS-CH3OH-HCl-H2O system. The conversion from gel to glass during heat treatment stage was investigated using TG-DTA, XRD, IR and SEM and characteristics of the gel were examined by measuring bulk density, linear shrinkage and Vicker's hardness. A transparent silica glass was prepared from the gel after heat treatment at 1050℃.

• YAKHAK HOEJI
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• v.35 no.6
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• pp.461-465
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• 1991

Silica-based gel filtration chromatography has been used to characterize molecular weight of proteins. However, the molecular weight measured by this method was distorted by protein-silica interactions like hydrophobic and electrostatic forces. Therefore, we characterized protein-silica interaction using two forms of phytochrome (124 kDa) having different hydrophobicity and surface charge. PH and ionic strength affected the retention time of phytochrome suggesting that electrostatic force is the major interaction between protein and silica surface.

• Journal of the Korean Chemical Society
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• v.16 no.1
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• pp.46-49
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• 1972

Using an assumption of isoviscosity at the gel-point in the polymerization of divinylbenzene, the relations between viscosity equation, viscosity-molecular weight, and the chain transfer equation have been studied. A new equation for the calculation of chain transfer constant, $C_{tr}$, by measuring the gel time in place of the degree of polymerization has been suggested.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1733-1736
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• 2008

ZnO thin films with preferred orientation along the (0 0 2) plane were fabricated by a sol-gel method. The effects of the annealing temperature, time, and thickness were studied by investigating UV-visible spectra, FT-IR spectra, and XRD of ZnO films. The films were dried and annealed ed at $100^{\circ}C,\;200^{\circ}C$, and $300^{\circ}C$ for 1hr, 2hrs, and 3hrs, respectively. The film showed the preferred (0 0 2) orientation and high transmittance near 90% in the visible range. Also, SEM images of the films exhibited very smooth surfaces without holes and cracks. Schottky diodes were fabricated by using ZnO sol-gel material. Au and Al were used as electrodes to make Ohmic and Schottky contacts, respectively. The annealing temperature, time and the thickness dependent I-V characteristics were presented in this article.

• Journal of the Korean Ceramic Society
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• v.26 no.4
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• pp.471-478
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• 1989

In this study we investigated the gelation time of sol which containing mixtures of TEOS with H2O, ethanol, HCl in the preparation of monolithic silica glass through Sol-Gel method. In this case apparent activation energies were observed by Arrhenius equation. We investigated the conversion from gel to glass in drying and heat treatment stages using DT-TG, FT-IR, XRD analysis and dried gel conversed to glass by heat treatment up to 85$0^{\circ}C$. The results of this experiment showed that the gelation time of solutions were promoted when increasing the amount of addition of H2O and HCl catalyst for TEOS and high reaction temperature of solution.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.6
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• pp.419-426
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• 2008

Physicochemical characteristics of gelatin extracted from abdominal skin of yellowfin tuna (Thunnus albacares), were investigated by comparing its proximate composition, pH, amino acid composition, viscoelastic properties, gel strength and SDS-PAGE patterns, with those of bovine and porcine gelatins. The effects of gelatin concentration, maturation time, heat and freeze treatments on the gel strength of yellowfin tuna abdominal skin gelatin were studied. Amounts of $\alpha$-chains, $\beta$- and $\gamma$-components of yellowfin tuna abdominal skin gelatin were higher than those of the two mammailan gelatins. Yellowfin tuna abdominal skin gelatin had the lowest imino acids (proline and hydroxyproline) content, which was consistent with that of other fishes. However, yellowfin tuna abdominal skin gelatin was highest in glycine, alanine, and lysine. The gel strengths of all gelatins were proportional to the concentration of gelatin, but yellowfin tuna abdominal skin gelatin exhibited the greatest gel strength at each concentration. Yellowfin tuna abdominal skin gelatin required a longer maturation time than the two mammalian gelatins to form a firm gel. Higher heating temperature decreased the gel strength of yellow fin tuna abdominal skin gelatin more than in the two mammalian gelatins. Freezing decreased the gel strength of bovine gelatin only slightly, but longer freezing times resulted in greater reductions in gel strength in the yellowfin tuna abdominal skin and porcine gelatins.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.232-233
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• 2006

In recent years the interest in organic/inorganic hybrid materials has increased at a fast rate. Nano organic-inorganic hybrid composites have shown advantages for preparing hard coating layers. Especially, nano hybrid composite has low environmental pollution. It has high transparency, hardness, toughness, thermal dissociation temperature, hydrophobicity by using nano sized inorganic material. There are many ways in which these materials may be synthesized, a typical one being the use of silica and silanes using the sol-gel process. The structure of sol-gel silica evolves as a result of these successive hydrolysis and condensation reactions and the subsequent drying and curing. The sol-gel reactions are catalyzed by acids and produce silica sol solutions. The silica sol grows until they reach a size where a gel transition occurs and a solid-like gel is formed. Colloidal silica(CS)/silane sol solutions were synthesized in variation with parameters such as different acidity and reaction time. In order to understand their physical and chemical properties, sol-gel coating films were fabricated on glass. From all sol-gel solutions, seasoning effect of sol-gel coating layer on glass was observed.