• Restorative Dentistry and Endodontics
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• 제28권5호
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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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• 제30권2호
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• pp.86-94
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• 2005

비금속 지대치 재료의 구강 내 환경변화에 따른 물리적 성질을 구명하기 위하여 4종의 지대치 재료를 다양한 환경에 보관한 후 굴곡강도 및 표면경도의 변화를 관찰하여 조건에 따른 영향을 구명하고자 이 연구를 시행하였다. Bisfil Core, Core Max, Fuji IX GP, Miracle Mix를 사용하여 굴곡강도 측정을 위한 시편을 제작한 후 최대하중을 측정하여 굴곡강도와 굴곡탄성계수를 계산하였다. 표면경도 측정을 위하여 아크릴릭 레진블럭에 상기 4종의 재료를 충전하여 중합시킨 후 순차 연마하여 경도측정을 위한 시편을 제작하고 Vickers hardness를 계산하였다. 1. 굴곡강도는 Core Max에서 가장 높고 Miracle Mix에서 가장 낮았다. 2. $37^{\circ}C$ 증류수에 24시간 보관한 군에서 Bisfil Core가 경도가 가장 높았다. 3. 30일 저장군에서는 Core Max가 경도가 가장 높았다. 4. 모든 군에서 Miracle Mix가 가장 낮은 경도를 나타냈다. 5. $2\%$ NaF용액과 0.02N lactic acid용액은 증류수보다 지대치 재료의 굴곡강도와 표면경도를 저하시켰다.

• 한국식품영양학회지
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• 제12권5호
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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.

• 한국초지조사료학회지
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• 제29권3호
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• pp.235-244
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• 2009

본 시험은 사일리지 조제시 품질 개선을 위한 젖산균 첨가제를 개발하기 위하여 2000년부터 2002년까지 국립축산과학원 초지사료과 조사료 분석실험실에서 수행하였다. 보리는 한국에서 중요한 식량작물로서 대부분이 식량으로 이용되나 곡실부분이 많아 가축의 사료로도 활용되며 특히 총체보리로 하여 반추가축의 조사료로 활용되고 있다. 본 시험은 우량 보리 사일리지에서 젖산균을 수집하여 0.02% $NaN_2$가 함유된 MRS agar에 도말하여 생장을 보며 1차 선발한 후 MRS broth에서 다시 배양하여 생장 능력과 산생성 능력을 평가하여 총 4종의 균주를 선발하였다. 선발된 균주는 그람 양성, 로드형, 카탈라제를 생성하지 않으며 생화학적 특성과 기질 이용성을 평가한 결과 Lactobacillus plantarum으로 판명되었다. 선발된 균주는 시중 판매되는 첨가제 등과 함께 호숙기의 보리 사일리지에 첨가하여 2개월후 사일리지의 품질을 조사한 결과 B2-2 미생물 처리구애서 pH가 낮았고 젖산함량도 높게 나타났다. 사일리지 품질 점수와 등급에 있어서도 B2-2 처리구가 높게 나타났다. 따라서 이상의 결과를 종합하여 볼 때 B2-2 균주는 보리 사일리지용 우량 미생물로 추천되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제14권2호
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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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• 제29권2호
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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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• 제39권1호
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• pp.54-59
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• 1996

김치에서 분리한 유산균 중에서 Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli(ATCC33694) 그리고 Bacillus substilis(ATCC 6633) 등 5종의 미생물에 대한 항균성이 우수한 3주(No. 49, No. 61, No. 75)를 최종 선발하여 동정한 결과 Lactobacillus plantarum으로 동정 되었다. 이들 3 균주를 starter로 사용하여 요구르트 등 여러 발효식품에 응용할 수 있는지 검토하기 위하여, 이들 균주로 요구르트를 제조한 후 요구르트의 ${\beta}-galactosidase$ 활성도를 균주 첨가 후 24시간 부터 72시간 동안 경시적으로 조사하였다. 그 결과 48시간 후에 효소활성은 최고에 도달하였으며 그 후 시간이 경과함에 따라 감소하였다. 또한 2시간 동안 경시적으로 요구르트 고유의 pH값보다 낮은 산성조건에서 ${\beta}-galactosidase$ 활성도와 생존율을 측정한 결과 pH 3.5에서 2시간 후에는 3균주 모두 50% 정도 활성이 감소하였으나 pH 2.5와 pH 1.5에서 ${\beta}-galactosidase$ 활성은 거의 없었다. 유산균의 생존율은 pH 3.5에서 2시간 후 거의 변화가 없었고, pH 2.5에서는 각각 $0.12%{\sim}0.75%$ 그리고 pH 1.5에서는 생존율이 거의 없었다. 한편, 제조 요구르트의 이화학적 성질을 조사한 결과 요구르트 고유의 pH 값은 4.08 부터 4.30사이이었으며, 적정산도는 $1.05{\sim}l.25%$ 점도는 $1,818{\sim}2,124\;cps$, 생균수는 $7.3{\times}10^8{\sim}3.0{\times}10^9\;cfu/m{\ell}$였다. 유산균이 살아있는 상태로 장내에 도달할 수 있는지의 여부를 간접적으로 나타내는 완충능을 측정하기 위하여 1.0N HCl로 요구르트 $100\;m{\ell}$를 고유의 pH값에서 2단위 낮은 pH값까지 적정한 결과 소모된 HCl량은 $11.98{\sim}13.02\;m{\ell}$이었고 1.0 N NaOH로 4단위 높은 pH값까지 적정하는데 소모된 NaOH량은 $10.82{\sim}12.86\;m{\ell}$로 시판 요구르트 보다 높은 완충능을 보여 주었다.

• 한국축산식품학회지
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• 제35권1호
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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.

• 한국식품조리과학회지
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• 제14권5호
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• pp.589-596
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• 1998

본 연구는 대두단백질의 풍미와 기능성의 향상을 목적으로 효소처리한 분리대두단백에 fructooligosaccaride, galactooligosaccaride , isomaltooligosaccaride를 첨가하여 3종류의 비피더스균으로 각기 배양시킨 soy yogurts의 pH, 산도, 생균수, $\alpha$-galactosidase의 활성 , 유기산과 n-hexanal 및 acetaldehyde의 함량을 연구하였다. pH에 있어서 올리고당의 종류에 따라서는 유의차가 없었으나 균주의 종류에 따라서는 유의차가 있었다. 따라서 B. bifidum 배양군의 pH가 5.26~5.30로 가장 높았고 B. breve 배양군은 4.76~4.86이었으며, B. infantis 배양군은 4.38~4.40로서 가장 낮았다. 적정산도는 pH와 유사한 경향을 나타내어 올리고당의 종류에 따라서는 유의차가 없었으나 균주의 종류에 따라서는 유의차가 있었다. 따라서 B. bifidum 배양군의 산도가 0.81~0.84%로 가장 낮았고 B. breve 배양군은 0.97-1.04% 였으며, B. infantis 배양군은 1.39~1.41%로 가장 높았다. 생균수는 올리고당의 종류에 따라서는 대체로 근사한 수치를 나타내었으나 균주의 종류에 따라서는 경시적인 차이가 있었으며 모든 시료들이 $10^{9}$ CFU/ml 이상의 생균수를 포함하는 것으로 나타났다. 한편 B. infantis로 배양한 soy yogurts를 4$^{\circ}C$에서 7일간 저장한 후 생균수를 측정한 결과 $10^{9}$ CFU/ml를 나타내어 초기생균수를 거의 유지하였다. $\alpha$-Galactosidase 활성은 B. infantis, B. bifidum, B. breve 순으로 높았으며 활성이 가장 높았던 B. infantis의 활성을 100%로 하였을 경우 B. bifidum B. breve의 활성은 각각 32.7, 26.0% 이었다. 유기산 중에서 lactic acid와 acetic acid은 적정산도의 결과와 유사한 경향을 나타내어 B. infantis 배양군, B. breve 배양군, B. bifidum 배양군 순으로 높았으며 propionic acid는 반대경향을 나타내었고 올리고당 종류에 따라서는 모든 시료에서 유의차가 없었다. 휘발성 향기성분 중에서 콩비린내를 발생시키는 성분인 n-hexanal은 B. breve배양군이 B. bifidum과 B. infantis 배양군 보다 농도가 높았으며 acetaldehyde는 0.02~0.52 ppm으로 극미량이 검출되었고 올리고당 종류에 따라서는 모든 시료에서 유의차가 없었다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권5호
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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.