• Korean Journal of Food Science and Technology
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• v.21 no.2
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• pp.185-191
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• 1989

The combined effects of heat treatment and ${\gamma}-irradiation$ on the inactivation of major lactic acid bacteria associated with Kimchi fermentation were investigated. The radiosensitivities $(D_{10}\;values)$ of lactic acid bacteria in case of a single treatment of irradiation were 0.61 kGy in Lactobacillus brevis, 0.60 kGy in Lactobacillus plantarum, 0.50 kGy in Leuconostoc mesenteroides, 0.4 kGy in Pediococcus cerevisiae, 0.39 kGy in Streptococcus faecalis. The heat sensitization $(D_{min}\;values)$ by a single treatment of heat ranged 9.2-15.6 at $50^{\circ}C$ and 3.7-5.5 at $60^{\circ}C$. Synegistic effects were shown in the radiosensitivities of Streptococcus faecalis, Pediococcus cerevisiae, Lactobacillus plantarum, and Lactobacillus brevis by the combined treatment(Dose multiplying factors ranged $1.20{\sim}1.56$). It seems, therefore, that the combined treatment can be applied to the radiation preservation of Kimchi, minimizing the side-effects like physical changes induced by the high dose irradiation or heat treatment.

• The Journal of Advanced Prosthodontics
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• v.8 no.2
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• pp.75-84
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• 2016

PURPOSE. To evaluate the effect of various surface treatments on the surface structure and shear bond strength (SBS) of different ceramics. MATERIALS AND METHODS. 288 specimens (lithium-disilicate, leucite-reinforced, and glass infiltrated zirconia) were first divided into two groups according to the resin cement used, and were later divided into four groups according to the given surface treatments: G1 (hydrofluoric acid (HF)+silane), G2 (silane alone-no heat-treatment), G3 (silane alone-then dried with $60^{\circ}C$ heat-treatment), and G4 (silane alonethen dried with $100^{\circ}C$ heat-treatment). Two different adhesive luting systems were applied onto the ceramic discs in all groups. SBS (in MPa) was calculated from the failure load per bonded area (in $N/mm^2$). Subsequently, one specimen from each group was prepared for SEM evaluation of the separated-resin-ceramic interface. RESULTS. SBS values of G1 were significantly higher than those of the other groups in the lithium disilicate ceramic and leucite reinforced ceramic, and the SBS values of G4 and G1 were significantly higher than those of G2 and G3 in glass infiltrated zirconia. The three-way ANOVA revealed that the SBS values were significantly affected by the type of resin cement (P<.001). FIN ceramics had the highest rate of cohesive failure on the ceramic surfaces than other ceramic groups. AFM images showed that the surface treatment groups exhibited similar topographies, except the group treated with HF. CONCLUSION. The heat treatment was not sufficient to achieve high SBS values as compared with HF acid etching. The surface topography of ceramics was affected by surface treatments.

• International Journal of Industrial Entomology and Biomaterials
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• v.37 no.2
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• pp.36-42
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• 2018

Recently, silk sericin has attracted attention because of its unique properties as a biomaterial, including its UV resistance, moisturizing effect on skin, and wound-healing effect. Therefore, the preparation of sericin in various forms such as gel, film, fiber, and sponge is studied for cosmetic and biomedical applications, and the effect of the preparation conditions on the structure and properties of sericin forms is examined to maximize its performance. In this study, silk sericin films were prepared under different preparation conditions and heat-treated at high temperatures ($100-250^{\circ}C$) to examine the effect of heat treatment on the film structure. The order of the crystallinity index of the untreated sericin film is as follows: F25 (sericin film cast from formic acid) > WE25 (ethanol treated sericin film cast from water at $250^{\circ}C$) > W25 (sericin film cast from water at $250^{\circ}C$) > W100 (sericin film cast from water at $100^{\circ}C$). As the heat-treatment temperature was increased, the color of the sericin films changed gradually from colorless to yellow, brown, and black depending on the temperature. The crystallinity of the sericin film changed after the heat treatment, depending on the preparation condition. Whereas a sericin film cast from formic acid (F25) started to lose its crystallinity at $200^{\circ}C$, thus undergoing the highest loss of crystallinity among the sericin films studied, the rest (W25, WE25, and W100) showed a decrease in crystallinity at $250^{\circ}C$, owing to the disruption of the ${\beta}$-sheet crystallites due to heat.

• Korean Journal of Food Science and Technology
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• v.52 no.6
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• pp.616-621
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• 2020

Sinapinic acid is a widely-distributed phenolic acid in various edible plants. In this study, changes in chemical stability and biological activities of sinapinic acid by heat treatment were evaluated at different pH values. The decomposition of sinapinic acid with heating at 95℃ was accelerated at higher pH; the residual levels after 10 min of heating were 80, 45 and 24% at pH 6, 7 and 8, respectively. Levels of reactive oxygen species derived from sinapinic acid also increased after heating at pH 7 and 8. ABTS radical scavenging activities and ferric reducing antioxidant power of sinapinic acid were reduced significantly after heating at pH 7 and 8. The cytotoxic activity of sinapinic acid against HCT116 cells was significantly enhanced after heating at pH 8 with decreased glutathione levels. The results suggest that heat treatment causes changes in the chemical stability and biological activities of sinapinic acid, and such changes are more prominent at higher pH.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.1
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• pp.95-104
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• 1994

This study was carried out to investigate the effect of sub-atmosphere on the fermentation and heat treatment after fermentation of Kimchi. When the results from the conditions of atmosphere and under-atmosphere were compared, the growth of lactic acid bacteria was increased but the growth of aerobic bacteria was decreased under 560mmHg and 360mmHg. The number of total microorganism was decreased and simultaneously damaged to the tissue of Kimchi under 0mmHg. Kimchi fermented under 560mmHg and 360mmHg had longer storage duration than that of atmosphere. Among the several conditions, the result of heat treatment under 460-260mmHg was the best. the treatment for 4 minutes at 80$^{\circ}C$, 2 minutes at 100$^{\circ}C$, and 1 minute at 120$^{\circ}C$ was good in tissue states and storage.

• Journal of the Korean Ceramic Society
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• v.12 no.2
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• pp.26-30
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• 1975

The experiment has been carried out to clarify the condition of acid treatment for preventing the crack formation caused by swelling and shrinking during acid leaching process. The borosilicate glass contained phosphorous pentoxide was chosen as the sample, which is recognized to be more homogeneous in phase separation. The various effects, such as kind, cocentration and acid temperature, were investigated. The experimental results are summerized as follows. (1) Sulfuric acid is more stable than hydrochrolic acid for preventing the crack. (2) The optimum concentration of acid lies in the range of 0.1~0.3N. (3) Higher temperature of the acid to treat the separated glass was more stable than lower temperature. (4) The rate of crack decreased with the longer period and the higher temperature of the heat treatment.

• Macromolecular Research
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• v.12 no.4
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• pp.367-373
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• 2004

We have developed a rigorous heat treatment method to improve the biocompatibility of chitosan as a tissue-engineered scaffold. The chitosan scaffold was prepared by the controlled freezing and lyophilizing method using dilute acetic acid and then it was heat-treated at 110$^{\circ}C$ in vacuo for 1-3 days. To explore changes in the physicochemical properties of the heat-treated scaffold, we analyzed the degree of deacetylation by colloid titration with poly(vinyl potassium sulfate) and the structural changes were analyzed by scanning electron microscopy, Fourier transform infrared (FT-IR) spectroscopy, wide-angle X-ray diffractometry (WAXD), and lysozyme susceptibility. The degree of deacetylation of chitosan scaffolds decreased significantly from 85 to 30% as the heat treatment time increased. FT-IR spectroscopic and WAXD data indicated the formation of amide bonds between the amino groups of chitosan and acetic acids carbonyl group, and of interchain hydrogen bonding between the carbonyl groups in the C-6 residues of chitosan and the N-acetyl groups. Our rigorous heat treatment method causes the scaffold to become more susceptible to lysozyme treatment. We performed further examinations of the changes in the biocompatibility of the chitosan scaffold after rigorous heat treatment by measuring the initial cell binding capacity and cell growth rate. Human dermal fibroblasts (HDFs) adhere and spread more effectively to the heat-treated chitosan than to the untreated sample. When the cell growth of the HDFs on the film or the scaffold was analyzed by an MTT assay, we found that rigorous heat treatment stimulated cell growth by 1.5∼1.95-fold relative to that of the untreated chitosan. We conclude that the rigorous dry heat treatment process increases the biocompatibility of the chitosan scaffold by decreasing the degree of deacetylation and by increasing cell attachment and growth.

• Journal of the Korean Ceramic Society
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• v.28 no.6
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• pp.488-494
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• 1991

In this study, the effects of catalyst and DCCA content were investigated in order to determine the optimum conditions of monolithic silica gel formation through sol-gel process. Formamide, oxalic acid, glycerol and dimethylformamide are used as DCCA. To observe the phenomena in drying and heat-treating of gels, we examined structural exchange of gels using FT-IR, TG-DTA and XRD. Monolithic gels were obtained by adding formamide and dimethylformamide as DCCA. According to the heat treatment schedule, silica glass is prepared by heat-treatment up to 1050$^{\circ}C$.

• Journal of the Korean Society for Heat Treatment
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• v.31 no.1
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• pp.6-11
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• 2018

The anodic oxidation behavior of Si-containing aluminum alloy for diecasting was investigated. Especially, the property changes during anodization both on aluminum 1050 and 9 weight percentage silicon containing aluminum (Al-9Si) alloys were analyzed by the static current test. In order to fabricate a uniform anodic oxidation film by effect of Al-Si compound, nitric acid containing hydrofluoric acid had been used as a desmutter for aluminum alloy after alkaline etching. It was found that the level of voltage of Al-9Si alloy during the static current test was almost as double as higher than aluminum 1050 through anodization. By adding hydrofluoric acid in the nitric acid electrolyte, the silicon compound on the surface was removed, and the optimum amount of added hydrofluoric acid could be derived. It was also observed that the size of silicon compound formed on the surface could be refined by heat treatment at $500^{\circ}C$ and followed water quenching.

• Korean Journal of Veterinary Research
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• v.40 no.4
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• pp.701-706
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• 2000

This study was carried out to select the lactic acid bacteria(Lactobacillus, Streptococcus and Bifidobacterium) and yeast for probiotic use in pigs. Acid-tolerant 536 strains were isolated from the feces of 30 pigs. To select useful strains, the first screened strains were treated with strong acid solution(pH 2.5 to 3.0) for 3 hours and subsequentely treated with the anaerobic diluent solution containing 0.15% Oxgall for 3 hours. Among these strains, 151 strains showed strong tolerance to both acid and bile. Lactobacillus and Streptococcus tolerant to the acid and bile were treated with heat at $80^{\circ}C$ for 15 min, and at $70^{\circ}C$ for 5 min in Bifidobacterium and yeast. As a result of heat treatment, 38 strains were obtained as heat-tolerant strains. All of heat-tolerant strains were tested for antibiotic resistance against virginiamycin, sulfathiazole, aureomycin, neomycin, linsmycin, tiamulin and ASP250 which were used as feed additives for growth promotion in pigs. Finally, one strain each from Lactobacillus, Streptococcus, Bifidobacterium and yeast that showed resistance to acid, bile, heat and antibiotics was selected for probiotic use in pigs.