• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.509-516
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• 2005

For the purpose of comparing the bond strengths of compomers to composite resin, composite Z250, and two polyacid modified composite resin, Dyract AP and F2000, were selected and investigated using universal testing machine for measuring the shear bond strengths. Additionally, the failure modes were examined by observing the fractured surfaces of each specimen. The following results were obtained. 1. The shear bond strength of Dyract AP to Z250 were higher than those of F2000, but there was no statistically significant difference between group 1 and group 3(p>0.05), and groups using fresh compomers showed higher bond strength than those using aged compomers(p<0.05). 2. After measuring the shear bond strength of each group, it was highest in group 5 and was lowest in group 9(p<0.05). 3. Although there was no statistically significant difference, groups treated with thermocycling showed lower bond strengths than those of non-thermocycling groups. 4. Overall compomer/composite resin failures were adhesive. Cohesive failures occurred mainly in groups using bonding agent. Based on these results, the application of a bonding agent on fresh polyacid-modified resin composite increases the bond strength between polyacid-modified resin composite and composite resin. Additionally, the surface of aged polyacid-modified resin composite has to be roughened mechanically and a bonding agent has to be used in combination with composite resin.

• The Korean Journal of Mycology
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• v.1 no.2
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• pp.15-23
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• 1973

Mold producing cellulase were isolated from rotten woods, and identified as the three species: Aspergillus niger van Tieghem, Aspergillus schiemanni Thom and Trichoderma viride Pers. In this paper, culture conditions in the media and characteristics of these strains were investigated. Using these strains, we have conducted a research concerning the utilization of farm product waste materia's. 1. Optimum conditions for the cellulase formation were as follows. KM 10-1; pH 5.2-5.5, $35^{\circ}C$, incubation time 6 days. OL 11-1; pH 5.5, $30-35^{\circ}C$, incubation time 6 days. SH 9-2; pH 5.5, $30^{\circ}C$, incubatoin time 6 days. 2. Their cellulase activities in their optimum condition were as follows: KM 10-1; CMC-LP 78.5% CMC-SP 4.0 glucose mg/gm of the cultures/min. OL 11-1; CMC-LP 89.9%, CMC-SP 4.9 glucose mg/gm of the cultures/min. SH 9-2; CMC-I.P 77.4%, CMC-SP 3.9 glucose mg/gm of the cultures/min. 3. Hydrolysis of animal feed containing a large quantity (23-30%) of cellulose by means of the crude enzyme in the selected strains resolved 30% of the cellulose contained in the animal feed.

• The Korean Journal of Mycology
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• v.48 no.3
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• pp.355-367
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• 2020

One hundred representative species of fungi in Korea were selected and their Korean names were proposed to increase interest in fungi among Korean people. This task was performed under the supervision of the Committee of Mycological Terms, under the Korean Society of Mycology. First, the committee established the criteria for selecting 100 representative species of fungi in Korea and then selected the candidate fungal species accordingly. To ensure the uniformity and stability of Korean fungal names, the principle of naming fungi in Korean was established, and the candidate Korean fungal names were presented accordingly. Finally, the candidate Korean fungal names were posted online to collect opinions of the members of the Korean Society of Mycology. The candidate Korean names of the plant pathogenic fungi and mushrooms were reviewed by the Korean Society of Plant Pathology and the Korean Society of Mushroom Science, respectively. After their opinions were considered, the Korean names for 100 representative fungi in Korea were finally determined. The 100 fungi comprised 41 common molds and yeasts, 28 plant pathogenic fungi, and 31 mushrooms.

• Food Science and Preservation
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• v.20 no.2
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• pp.141-150
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• 2013

For the investigation of the quality loss of mulberry during distribution, the deterioration rate, microorganism growth, and sensory quality of mulberry kept at 20, 10 and $0^{\circ}C$, respectively, were investigated. Based on the results, the optimum temperature for extending the freshness of mulberry was examined in the temperature range of -1.5 to $1.5^{\circ}C$. The level of mold in the mulberry kept at 20 and $10^{\circ}C$, respectively, was much higher than that kept at $0^{\circ}C$. The quality of the mulberry deteriorated seriously after two days at $20^{\circ}C$, after six days at $10^{\circ}C$, and after 12 days at $0^{\circ}C$. The marketability of mulberry as determined via sensory evaluation was much more prolonged by decreasing the keeping temperature from 20 to $0^{\circ}C$. To extend the freshness of mulberry using these results, the optimum temperature was evaluated at the range of -1.5 to $1.5^{\circ}C$ for 25 days. During storage, the changes in the color and pH of the berry were not significantly different by storage temperature, but the microbial levels and deterioration rate increased in the order of 1.5, 0, and $-1.5^{\circ}C$. In particular, the firmness of the mulberry decreased rapidly at $1.5^{\circ}C$, showing a significant difference from the others. The titratable acidity and sugar contents decreased gradually at all the applied temperatures. The anthocyanin content decreased sharply at $1.5^{\circ}C$ but gently changed at $-1.5^{\circ}C$. Through the sensory results of this study, it was adjudged that the marketability of mulberry could be maintained about 0.7 times at $1.5^{\circ}C$ and 1.3 times at $-1.5^{\circ}C$ compared with the marketability at $0^{\circ}C$, respectively.

• Korean Journal of Food Science and Technology
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• v.7 no.4
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• pp.229-237
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• 1975

An attempt was made to utilize the enzyme produced by Asp. oryzae as meat tenderizer. The production, purification, and various properties of proteinase produced by Asp. oryzae were investigated. Results obtained are as follow; 1. A strain which had the highest proteolytic activity was selected among 9 Aspergillus species. 2. Culture medium consisted of wheat bran 10g, 2% glucose, 0.03% urea and 0.1% $MgSO_4$ (pH 6.5). Mold was incubated at $30^{\circ}C$ for 3 days. 3. Enzyme extract from culture medium were fractionated with ammonium sulfate and purified by Sephadex G-75 column chromatography. 4. When pH of reaction mixture was controlled, maximal activity of proteinase by Asp. oryzae was obtained at pH 3, pH 6.6, $8.4{\sim}8.5$ and pH 10.0 to 10.5. Those results were interpreted to show that enzyme consists of acid proteinase, neutral proteinase and alkaline proteinase. Enzyme was stable at pH 6 to 10. 5. Opt. temperature for proteinase activity was $50^{\circ}C$, but enzyme was stable up to $40^{\circ}C$. 6. The proteinase was inhibited by $Ag^+$. It was also inhibited by EDTA. 7. When myofibrillar proteins were treated by proteinase from Asp. oryzae, ATPase activities of myofibrillar proteins changed remarkably. Accordingly, it was concluded that proteinase produced by Asp. oryzae were able to be used as meat tenderizer.

• Korean Journal of Food Science and Technology
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• v.7 no.4
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• pp.200-207
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• 1975

This experiment was carried out to investigate the chemical composition and microflora of soy sauce during storage under the different temperature. The results obtained are as follows. (1) Total nitrogen, color density, specific gravity and sodium chloride concentration of soy sauce showed a increasing tendency in the progress of storage period. Open-storage state at $30^{\circ}C\;and\;15^{\circ}C$ were responsible to the increase of components as compare with close-storage state at $5^{\circ}C$. (2) pH and buffer action were not almost changed during the storage. (3) Alcohol and sugar contents of soy sauce showed a decreasing tendency in the process of storage period, especially in the case of open state alcohol being almost disappeared within 11 months in all groups. (4) The number of common bacteria in one ml of soy sauce were counted as $96{\times}10^4$ before pasteurization and $10^3$ after pasteurization. The osmophilic bacteria was counted as $38{\times}10^4$, $10^2$ after pasteurization. (5) The spore number of mold in one ml of soy sauce were counted $32{\times}10^7$ before pasteurization, 58 after pasteurization and 10 to $10^2$ in the progress of storage period. (6) The bacteria number of soy sauce were somewhat decreased with the passing, of the time. The group of high temperature and open state were more notable than low temperature and close state.

• Korean Journal of Microbiology
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• v.53 no.1
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• pp.39-48
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• 2017

In order to evaluate the diversity of microbial population of Korean traditional Deonjang and Gochujang produced in Jeju, Jeonnam, and Jeonbuk province area, microbial communities were analyzed using next generation sequencing. In this result, the dominant bacteria of Deonjang in three area were Bacillus amyloliquefaciens, Tetragenococcus halophilus, and Bacillus was major dominant bacteria in Jeonnam (43.16%) and Jeonbuk (64.54%) area. But in Jeju area, Bacillus was 0.22%, which was significantly different from the other two. Equally, the dominant fungi of Deonjang in 3 area were Candida versatilis. Common fungus in Jeonnam and Jeonbuk area was Candida sp., respectively, 64.22% and 33.68% and Micor sp. was a common fungus in Jeonnam (15.66%) and Jeonbuk area (36.73%). But in Jeju area, Candida sp. and Zygosaccharomyces rouxii were dominant than mold. Bacillus subtilis, Bacillus licheniformis, and B. amyloliquenfaciens were the preminant bacteria in the traditional Gochujang in three regions. But there were no common dominant fungi in the 3 regions. Aspergillus sp. and Rhizopus sp. prevailed in Jeju and Jeonnam region, and Zygosaccharomycess rouxii predominanted in Jeonbuk area. These results suggested that the difference in the samples collected for the study were classified into similar groups according to the characteristics of each sample rather than regional characteristics.

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.336-341
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• 2008

The objective of this research was to investigate the suitable cultivar for organic strawberry (Fragaria ananassa Duch.) cultivation in Korea. The six strawberry cultivars which were bred and commonly cultivated in Korea as forcing and semi-forcing culture were tested in this experiment. To achieve the objectives, various characteristics of these cultivars were investigated for two consecutive years such as growth habit, yield, fruit quality and occurrence rate of disease/pest. As results of this research, the total yield of 'Seolhyang' was the highest among cultivars tested in both forcing and semi-forcing cultivation. The average of soluble solid contents (SSC) in 'Seolhyang' was $12.0^{\circ}Bx$ that is lower than other cultivars and especially below $10^{\circ}Bx$ after March (high temperature period). But there was not much difference in SSC among 6 cultivars until the end of February. The average of hardness in 'Seolhyang' was 279g/${\phi}5\;mm$ which was a little higher than that of 'Akihime'. Titration acidity (TA) in 'Maehyang' was 0.69% which was the highest value among 6 cultivars. Total fresh/root weight of 'Seonhong' and leaf area of 'Seolhyang' were significant among other cultivars' ones in forcing culture. Growth habits (fresh weight, root weight, leaf area, etc.) showed no significant difference among cultivars in semi-forcing culture. The lowest occurrence rate for powdery mildew and aphids was found in 'Seolhyang', but gray mold was severer than other cultivars. The density of two spider mites was the lowest in 'Redpearl'. We have concluded that 'Seolhyang' is the most suitable cultivar for organic strawberry cultivation by the result of yield, fruit quality and resistance of disease/pest.

• Restorative Dentistry and Endodontics
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• v.31 no.4
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• pp.263-268
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• 2006

Recently, self-etching adhesive system has been introduced to simplify the clinical bonding proce- dures. It is less acidic compared to the phosphoric acid, thus there is doubt whether this system has enough bond strength to enamel. The purpose of this study was to investigate the influence of additional etching on the adhesion of resin composite to enamel. Ninety extracted bovine permanent anterior teeth were used. The labial surfaces of the crown were ground with 600-grit abrasive paper under wet condition. The teeth were randomly divided into six groups of 15 teeth each. Clearfil SE $Bond^{\circledR},\;Adper^{TM}$ Prompt L-Pop and Tyrian $SPE^{TM}$ were used as self-etching primers. Each self-etching primers were applied in both enamel specimens with and without additional etching. For additional etching groups, enamel surface was pretreated with 32% phosphoric acid (UNI-ETCH, Bisco, Inc., Schaumburg, IL. USA). Hybrid resin composite Clearfil AP-X, (Kuraray Co., Ltd., Osaka, Japan) was packed into the mold and light-cured for 40 seconds. Twenty-four hours after storage, the specimens were tested in shear bond strength. The data for each group were subjected to independent t - test at p < 0.01 to make comparisons among the groups. In Clearfil SE $Bond^{\circledR}$, shear bond strength of additional etching group was higher than no additional etching group (p < 0.01). In $Adper^{TM}$ Prompt L-Pop and Tyrian SPE, there were no significant difference between additional etching and non-etching groups (p > 0.01). In conclusion, self-etching adhesive system with weak acid seems to have higher bond strength to enamel with additional etching, while self-etching adhesive system with strong acid seems not.

• Restorative Dentistry and Endodontics
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• v.24 no.2
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• pp.299-309
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• 1999

The composite resin, due to its esthetic qualities, is considered the material of choice for restoration of anterior teeth. With respect to shade control, the direct-placement resin composites offer some distinct advantages over indirect restorative procedures. Visible-light-cured (VLC) composites allow dentists to match existing tooth shades or to create new shades and to evaluate them immediately at the time of restoration placement. Optimal intraoral color control can be achieved if optical changes occurring during application are minimized. An ideal VLC composite, then, would be one which is optically stable throughout the polymerization process. The shade guides of the resin composites are generally made of plastic, rather than the actual composite material, and do not accurately depict the true shade, translucency, or opacity of the resin composite after polymerization. So the numerous problems associated with these shade guides lead to varied and sometimes unpredictable results. The aim of this study was to assess the color changes of current resin composite restorative materials which occur as a result of the polymerization process and to compare the color differences between the shade guides provided with the products and the actual resin composites before- and after-polymerization. The results obtained from this investigation should provide the clinician with information which may aid in improved color match of esthetic restoration. Five light activated, resin-based materials (${\AE}$litefil, Amelogen Universal, Spectrum TPH VeridonFil-Photo, and Z100) and shade guides were used in this study. Three specimens of each material and shade combination were made. Each material was condensed inside a 1.5mm thick metal mold with 10mm diameter and pressed between glass plates. Each material was measured immediately before polymerization, and polymerized with Curing Light XL 3000 (3M Dental products, USA) visible light-activation unit for 60 seconds at each side. The specimens were then polished sequentially on wet sandpaper. Shade guides were ground with polishing stones and rubber points (Shofu) to a thickness of approximately 1.5mm. Color characteristics were performed with a spectrophotometer (CM-3500d, Minolta Co., LTD). A computer-controlled spectrophotometer was used to determine CIELAB coordinates ($L^*$, $a^*$ and $b^*$) of each specimen and shade guide. The CIELAB measurements made it possible to evaluate the amount of the color difference values (${\Delta}E{^*}ab$) of resin composites before the polymerization process and shade guides using the post-polishing color of the composite as a control, CIE standard D65 was used as the light source. The results were as follows. 1. Each of the resin composites evaluated showed significant color changes during light-curing process. All the resin composites evaluated except all the tested shades of 2100 showed unacceptable level of color changes (${\Delta}E{^*}ab$ greater than 3.3) between pre-polymerization and post-polishing state. 2. Color differences between most of the resin composites tested and their corresponding shade guides were acceptable but those between C2 shade of ${\AE}$litefil and IE shade of Amelogen Universal and their respective shade guides exceeded what is acceptable. 3. Comparison of the mean ${\Delta}E{^*}ab$ values of materials revealed that Z100 showed the least overall color change between pre-polymerization and post-polishing state followed by ${\AE}$litefil, VeridonFil-Photo, Spectrum TPH, and Amelogen Universal in the order of increasing change and Amelogen Universal. Spectrum TPH, 2100, VeridonFil-Photo and ${\AE}$litefil for the color differences between actual resin and shade guide. 4. In the clinical environment, the shade guide is the better choice than the shade of the actual resin before polymerization when matching colors. But, it is recommended that custom shade guides be made from resin material itself for better color matching.