• Restorative Dentistry and Endodontics
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• v.28 no.5
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• pp.369-377
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• 2003

The aim of this study was to evaluate the effect of two polishing methods and chemical conditioning on the surface of hybrid composites. Ninety cylindrical specimens (diameter：8mm, depth：2mm) were made with three hybrid composites-Filtek Z250, Tetric Ceram. DenFil. Specimens for each composite were randomly divided into three treatment subgroups $^{\circled1}$ Mylar strip (no treatment). $^{\circled2}$ Sof-Lex XT system, $^{\circled3}$ PoGo system. Average surface roughness(Ra) was taken using a surface profilometer at the time of setting and after immersion into 0.02N lactic acid for 1 week and 1 month. Representative specimens were examined by scanning electron microscopy. The data were analyzed using ANOVA and Scheffe's tests at 0.05% significance level. The results were as follows：1. Mylar strip resulted in smoother surface than PoGo and Sof-Lex system (p<0.001). Sof-Lex system gave the worst results. 2. Tetric Ceram was smoother than DenFil and Z250 when cured under only mylar strip. However, it was significantly rougher than other materials when polished with PoGo system. 3. All materials showed rough surface after storage in 0.02N lactic acid, except groups polished with a PoGo system. The PoGo system gave a superior polish than Sof-Lex system for the three composites. However. the correlation to clinical practice may be limited, since there are several processes. such as abrasive, fatigue, and corrosive mechanisms. Thus. further studies are needed for polishing technique under in vivo conditions.

• Restorative Dentistry and Endodontics
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• v.30 no.2
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• pp.86-94
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• 2005

The purpose of this study was to measure the flexural strength and hardness of four core materials in 4 different medias and to evaluate the relationship between the physical properties. For the flexural strength, the specimens were prepared from each of the following materials: Bisfil Core, Core Max, Fuji IX GP, Miracle Mix and randomly divided into four groups and stored at 37 degree C in the following medias: distilled water for 24 hours (DW/1), distilled water for 30 days (DW/30). $2%$ NaF for 30 days (NF/30), 0.02N lactic acid for 30 days (LA/30). After storage, the specimens were subjected to flexural strength testing and calculated to flexural modulus. For hardness testing, specimens were prepared from four materials and storaged in the uniform way. After storage, the specimens were subjected to Vicker's hardness testing. 1. The flexural strength of Core Max were the highest, and the flexural strength of Miracle Mix were the lowest. 2. The hardness of Bisfil Core were the highest. 3. The hardness of Core Max were the highest. 4. The hardness of Miracle Mix were the lowest. 5. $2\%$ NaF and 0.02N lactic acid negatively affected the flexural strength and hardness of four core materials.

• The Korean Journal of Food And Nutrition
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• v.12 no.5
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• pp.455-461
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• 1999

The possibility of wine making from soft and dried persimmon and the effects of treatment for persimmon on the quality of wine have been investigated. Soft persimmon was pretreated by two method of heat and hydrochloric acid treatment. Fermentation mash was composed of 12% persimmon and 15% of sucrose and was fermented at 17$^{\circ}C$ for 36 days. The fermentation using persimmons which were untreated and treated by acid was not successful because of contamination caused by lactic acid and acetic acid bacteria. Acidity of the fermented broth produced from boiled dried acid treated and untreated persimmon was 4,4, 5.0, 5,8 and 13.5ml(0.1N NaOH/10ml broth) respectively. Ethanol concentration of the fermented broth produced from boiled dried acid treated and untreated persimmon was 11.2, 10.0, 9.4 and 6.1% v/v respectively. The wine fermented for 28day's fermentation using boiled persimmon as substate had the best quality and stability. After 36day's fermentation using boild persimon following composition was obtained: 4.65% of total sugar 3.65% of reducing sugar 0.03mg/ml of protin 0.17$\mu$/ml of amino acid and 13.02 $\mu$g/ml of pectin. The pH and yeast cell of the boiled persimmon broth were 3.4 and 5.75 logCFU/ml. Fermented wine using dried persimmon had aslo good quality but the fermentation rate was slow.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.3
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• pp.235-244
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• 2009

This experiment was conducted to develop a new silage inoculant for barley at forage analysis laboratory, Grassland and Forages Division, National Institute of Animal Science, RDA from 2000 to 2002. Barley is very important crop in Korea. The great part of them is utilized as forage. Generally, it contains a lot of grains that are feed of animal, especially whole crop silage in ruminant. Efficient lactic acid bacteria were isolated from good barley silage by plating MRS agar containing 0.02% sodium azide, and assessed by growing and acid producing ability in MRS broth. Four lactic acid bacteria were selected, and were found to be Gram positive, rods and catalase negative and were identified to be Lactobacillus plantarum on the basis of the biochemical characteristics and utilization of substrates. Barley was ensiled at dough stage following treatment with four lactic acid bacteria, commercial inoculant, and no additive (control). After 2 months, B2-2 bacteria inoculated silage was lower pH and higher lactic acid content than others treatments. The Flieg's score and grade of B2-2 bacteria treated silage were higher than commercial inoculant. According to this experiment, Lactobacillus plantarum B2-2 (NLRI 201) was recommendable for good silage inoculant of whole crop barley silage.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.2
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• pp.211-215
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• 2001

Urea as a silage additive increases crude protein but reduces fermentation quality of silage by increasing pH and enhancing clostridial bacteria growth, especially in low sugar forages. Glucose and formic acid might be expected to compensate these defects caused by urea addition to grass silage. Thus, in this experiment urea formic acid or urea with glucose was applied to improve N content and the quality of napiergrass (Pennisetum purpureum Schumach.) silage. The first growth of napiergrass was harvested at 85 days of age and about 700 g of the grass was ensiled in laboratory silos (1.0 liter polyethylene containers) for 2, 7, 14, and 30 days at room temperature ($28^{\circ}C$). The treatments were no additives (control), urea, urea+glucose or urea+formic acid. Urea was added before ensiling at 0.5% of fresh weight of napiergrass and glucose and formic acid were added at 1% of fresh weight, respectively. After opening the silo, pH, dry matter content (DM), contents on DM basis of total N (TN), volatile basic nitrogen (VBN), lactic acid (LA), acetic acid (AA) and butyric acid (BA) were determined. The control at 30 days of fermentation showed 5.89 for pH with 13.8% for VBN/TN and 1.51% for AA. The addition of urea increased TN by about 1.5% units but decreased the fermentation quality by increasing pH from 5.89 to 6.86, increasing VBN/TN from 13.8% to 24.63%, increasing BA from 0.02% to 0.56%, and decreasing LA from 1.03% to 0.02%. Glucose addition with urea significantly decreased VBN/TN from 13.8% to 4.44% by reducing pH from 6.86 to 4.83 because of higher production of LA (2.62%). Adding urea and formic acid resulted in a more pronounced depression of VBN/TN and fermentation than the addition of urea and glucose. This study suggested that the combination of 1% glucose or 1% formic acid with 0.5% urea will improve nutritive value and fermentation quality of napiergrass silage.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.2
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• pp.211-218
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• 2016

This study evaluated the effect of Candida norvegensis (C. norvegensis) viable yeast culture on in vitro ruminal fermentation of oat straw. Ruminal fluid was mixed with buffer solution (1:2) and anaerobically incubated with or without yeast at $39^{\circ}C$ for 0, 4, 8, 16, and 24 h. A fully randomized design was used. There was a decrease in lactic acid (quadratic, p = 0.01), pH, (quadratic, p = 0.02), and yeasts counts (linear, p<0.01) across fermentation times. However, in vitro dry matter disappearance (IVDMD) and ammonia-N increased across fermentation times (quadratic; p<0.01 and p<0.02, respectively). Addition of yeast cells caused a decrease in pH values compared over all fermentation times (p<0.01), and lactic acid decreased at 12 h (p = 0.05). Meanwhile, yeast counts increased (p = 0.01) at 12 h. C. norvegensis increased ammonia-N at 4, 8, 12, and 24 h (p<0.01), and IVDMD of oat straw increased at 8, 12, and 24 h (p<0.01) of fermentation. Yeast cells increased acetate (p<0.01), propionate (p<0.03), and butyrate (p<0.03) at 8 h, while valeriate and isovaleriate increased at 8, 12, and 24 h (p<0.01). The yeast did not affect cellulolytic bacteria (p = 0.05), but cellulolytic fungi increased at 4 and 8 h (p<0.01), whereas production of methane decreased (p<0.01) at 8 h. It is concluded that addition of C. norvegensis to in vitro oat straw fermentation increased ruminal fermentation parameters as well as microbial growth with reduction of methane production. Additionally, yeast inoculum also improved IVDMD.

• Applied Biological Chemistry
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• v.39 no.1
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• pp.54-59
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• 1996

Three strains of inhibitory lactic acid bacteria (No. 49, No. 61, No. 75) against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escheirchia coli(ATCC33694) and Bacillus subtilis(ATCC6633) were isolated from kimchi, and then, identified to be Lactobacillus plantarum after examinations of their biological and physiological characteristics. To investigate a possible application of these three lactobacilli in milk fermentation industry, we made yogurts and then evaluated their ${\beta}-galactosidase$ activities at various; incubation time(from 24 hrs to 72 hrs). The result of experiment was that ${\beta}-galactosidase$ activities were reached maximum at 48 hrs and that reduced gradually with the lapse of time. And the ${\beta}-galactosidase$ activity of lactobacilli, and their viable cell counts at $37^{\circ}C$ for 2 hrs under various pH conditions were investigated. ${\beta}-galactosidase$ activities of 3 strains were reduced 50% at pH 3.5, but there were no remaining activities at pH 2.5, and pH 1.5, respectively. The frequency of the survival cell of lactobacilli in yogurt were $0.12{\sim}0.75%$ at pH 2.5, $$6.3{\times}10^{-5}{\sim}2.7{\times}10^{-3}% at pH 1.5, respectively, but there was no significant difference at pH 3.5. The values of original pH, titratable acidity as lactic acid, viscosity, and viable cells of yogurts were $4.08{\sim}4.30,\;1.05{\sim}1.25%,\;1,818{\sim}2,124\;cps\;and\;7.3{\times}10^8{\sim}3.0{\times}10^9\;cfu/m{\ell}$, respectively. To estimate buffer capacity of yogurt, the volume of 1.0 N HCl to 2 unit below original pH of yogurt($100\;m{\ell}$) was $11.98{\sim}13.02\;m{\ell}$ and the volume of 1.0N NaOH to 4 unit above original pH of yogurt($100\;m{\ell}$) was $10.82{\sim}12.86\;m{\ell}.

• Food Science of Animal Resources
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• v.35 no.1
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• pp.143-148
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• 2015

Yogurt powder is fermented milk processed in the form of dry yogurt, and has advantages such as stability, storability, convenience, and portability. China and Vietnam are important export target countries because of the increased demand for dairy products. Therefore, we surveyed dairy product standardization in order to establish an export strategy. Lactic acid bacteria counts are unregulated in Korea and Vietnam. In China, lactic acid bacteria counts are regulated at $1{\times}10^6$ colonyforming units (CFU)/mL and detected at $6.24{\pm}0.33\;Log\;CFU/mL$. All three countries have regulated standards for total bacterial counts. In China, total bacterial counts of milk powder are regulated to n=5, c=2, m=50,000, M=200,000 and detected at $6.02{\pm}0.12\;Log\;CFU/mL$, exceeding the acceptable level. Lactic acid bacterial counts appeared to exceed total bacterial counts. Coliform group counts, Staphylococcus aureus, Listeria monocytogenes, and Salmonella species were not detected. Acidity is not regulated in Korea and Vietnam. In China, acidity was regulated to over $70^{\circ}T$ and detected $352.38{\pm}10.24^{\circ}T$. pH is unregulated in all three countries. pH was compared to that of general fermented milk, which is 4.2, and that of the sample was $4.28{\pm}0.01$. Aflatoxin levels are not regulated in Korea and China. In Vietnam, aflatoxin level is regulated at 0.05 ppb. Therefore, all ingredients of the yogurt powder met the safety standards. This data obtained in this study can be used as the basic data in assessing the export quality of yogurt powder.

• Korean journal of food and cookery science
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• v.14 no.5
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• pp.589-596
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• 1998

This study was carried out to evaluate the quality attributes of soy yogurts prepared by different types of oligosaccharides (fructooligosaccharide, galactooligosaccharide , isomaltooligosaccharide) and Bifidobacteria (B. bifidum B. breve, B. infantis) containing enzyme treated soy protein isolate in terms of pH, titratable acidity, total number of viable cells of Bifidobacteria, ${\alpha}$-galactosidase activity, organic acids, volatile compounds. The pH values of soy yogurts fermented by B. bifidum showed the highest significantly but those fermented by B. infantis showed the lowest significantly, while the titratable acidity of soy yogurts were vice versa. The viable cells of Bifidobacteria of all soy yogurts showed more than 10$\^$9/ CFU/ml and soy yogurts fermented by B. infantis showing below pH 4.6 showed more than 10$\^$9/ CFU/ml after storage at 4$^{\circ}C$ for 7 days. The activity of ${\alpha}$-galactosidase showed the highest in the culture of B. infantis among the Bifidobacteria tested. Among the Bifidobacteria tested, the contents of lactic acid and acetic acid showed the highest in soy yogurts fermented by B. infantis but citric acid and propionic acid were the lowest. Among the Bifidobacteria tested, the contents of n-hexanal showed the highest in soy yogurts fermented by B. breve and a little amounts of acetaldehyde were present in all soy yogurts.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.5
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• pp.660-664
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• 2003

An attempt was made to evaluate the effects of total mixed rations (TMR) containing 17.5% forage neutral detergent fiber (NDF) from paragrass, paragrass+cassava chips and corn silages on the performance of dairy cows in the tropics. Experimental dietary treatments contained a similar content of total NDF, total non-fiber carbohydrates, crude protein and energy. Maximum and minimum temperature humidity index during the experimental period were 79.1-80.6 and 66.8-68.6, respectively. Among silage sources, there were no differences (p>0.05) in concentrations of acetic and propionic acids and butyric acid was undetectable. Concentration of lactic acid was higher (p<0.01) in corn silage but its pH was lower (p<0.01) than in paragrass and paragrass+cassava silages. Dairy cows on TMR containing corn silage not only gained more weight (161 and 46 vs. -189 g/d) but also consumed more feed (18.47, 15.84 and 14.49 kg/d), and produced more milk (23.89, 22.03 and 20.83 kg/d), 4% fat corrected milk (25.47, 24.05 and 22.02 kg/d), solids-not-fat (1.99, 18.3 and 1.73 kg/d) and total solid (3.10, 2.85 and 2.64 kg/d) compared with those on TMR containing paragrass+cassava and paragrass silages, respectively (p<0.01). Dairy cows on TMR containing paragrass+cassava silage were better in these respects (p<0.01). These results suggest that in formulating diets on an equal NDF basis for different forage qualities, diets higher in forage quality can stimulate higher DMI for dairy cows in the tropics and thus improve productivity.