• KSBB Journal
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• 제6권3호
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• pp.299-307
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• 1991

In this paper the effect of light on non-aerated Baker's Yeast(Saccharomyces cereuisiae) production and the protein excretion to the extracellular fluid is studied. Previous results in our laboratory indicate that at pH=5 and T-32$^{\circ}C$ yeast may be affected by light, but those differences seem to be within statistical variation of the data. In this paper, cell and extracellular protein concentrations along with redox potential are monitored for batch fermentations in the presence and absence of light at pH levels of 3 and 5 and at 31$^{\circ}C$, in order to explore whether possible light effects can be more readily discerned at lower pH values. Yeast particle size distributions are also determined over the course of fermentation using a particle counter in order to add one more measuring tool to our usual cell and total protein measurements. An apparently noticeable difference in the redox potential is observed between the light and the dark runs for early times for the pH=3 runs. The particle size distributions show differences in the particle diameters between light and dark runs at pH=3, but those differences fall within one standard deviation of the mean particle diameters.

• 대한가정학회지
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• 제32권1호
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• pp.229-238
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• 1994

The purpose of this study was to investigate the objectification of coloring matter abstraction of the way to natural dye by cathamus flower. Watersoluble carthamin in the dyeing cathamus flower was removed for the fastness of dyeing and only insoluble carthamon was abstracted which came by solvent such as Sodium hydroxide(NaOH) Potassium hydroxide(KOH) Sodium carbonate(Na2CO3)and Potassi-um carbonate(K2CO3) Carthamon made abstract essence from a carthamus flower out of the pH6, pH7, pH9, pH11, solvent and by using a UV/VIS Spectra according to the change of pH. Silk dyes with solution abstract carthamon and it was treated by 5 kinds of mordant. The table of surface-colors was measured by the number of dyeing the color of silk dyed and by the kind of mordant which treated with and the dyeing was evaluated by measuring Color Fastness to Light and Washing.

• Restorative Dentistry and Endodontics
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• 제22권2호
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• pp.637-647
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• 1997

The purpose of this study was to evaluate the effect of concentration and pH of lactic acid on the formation of artificial root caries lesions formation in bovine teeth. The characterictics of artificially produced early root lesions were observed with polarized light microscope and the depth of lesions were mearsured with measuring microscope The results were as follows: 1. In the group of low pH and high concentration of lactic acid, the progress of lesion formation was faster than that of high pH and low concentration lactic acid group. 2. In the same group, initial lesion progress faster, but progression rate was reduced as time goes by. 3. In the development of initial root caries, cementum was act as a barrier to protect dentin from lesion progression.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
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• pp.195-198
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• 2001

We developed the portable blood analysis system, which can be measured pH of the blood. This system is composed to electronic circuit, mechanism, and system software. Electronic circuit is composed to the sensor, pre-amp part, temperature regulation part, fluid sensing part, A/D(analog to digital) conversion part, main and peripheral device processing part. And the mechanism is composed to the flow cell and the liquid flow part. The liquid flow part is consisted of blood and washing control system under the control of the 6-channel solenoid valve and syringe rump. The system software is composed to measurement program, calibration program, washing and diagnostic program. The program of each routine is designed as sequential process for an efficiency. And the portable pH analysis system used two-point calibration method using the two types of corrective liquid. As a result, we obtained the calibration curve and calculated the value of pH. For verifying the system, we confirmed the output voltage of the sensor, and estimated reappearance of system using the standard liquid.

• Preventive Nutrition and Food Science
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• 제3권2호
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• pp.180-185
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• 1998

A regression equation was proposed for predicting protein digestibility using pH drop and free amino acid content. Results were compared with those determined by the pH drop method of Satterle et al. and with apparent in vivo digestibility in rats. Measurd free amino acid content prior to four enzyme digestion had an influence on calculating digestbiilty . Results from new equation correlated more highly (r=0.8434, difference average=2.304) with in vivo digestibility than the results of pH drop method (r=0.7603, difference average=10.099).

• 한국토양비료학회지
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• 제16권4호
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• pp.318-324
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• 1983

이온흡착, 전위차적정, 전기이동법 등을 이용 하여 kaolinite 현탄액의 전기 화학적 성질을 연구하였다. 0.001M 또는 0.1M NaCl 용액중에서 kaolinite로부터 용해되어 나온 알루미늄 이온이 $Na^+$ 및 $Cl^-$과 같이 지시이온으로서 kaolinite 표면에 흡착되는 것을 고려할 때 kaolinite는 pH independent + 및 -전하와 pH dependent + 및 -전하를 모두 가지고 있었다. 증류수와 0.001M NaCl 용액중에서 kaolinite 입자의 전기이동은 전기 이동셀(cell)에서 측정이 시작된 후 시간경과(전기이동 측정시간)에 관계없이 일정한 이동성을 나타냈으나 0.1M NaCl 용액중에서 kaolinite 입자는 등전점 (pH 4.7) 이상에서는 측정시간이 경과함에 따라 전하가 -에서 +로 변화하였다. 즉 최초 10초 동안에는 -전하를 가지며 그 후에는 +전하를 띠면서 전기이동 속도가 단계적으로 증가하게 되는데 약 10분 후에는 일정하게 되었다. 이것은 아마도 제일 바깥쪽 Octahedral layer 표면의 aluminol group의 부분들이 높은 이온 강도의 전해질 용액중에서 분해되어 복잡한 전기이중층(electric double layer)을 이루고 이것이 전기장 내에서 이동할 때 표면으로부터 counter이온들이 점차 떨어져 나가는 과정에서 전하(net charge)의 변화가 생기는 것으로 생각된다.

• 치위생과학회지
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• 제6권3호
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• pp.159-162
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• 2006

이 연구의 목적은 타액이 산성일때 치아우식과 연관이 있는 Streptococcus mutans 와 Lactobacillus spp.의 양을 조사하여 치아우식의 지표로 사용될 수 있는지를 관찰한 외국인을 대상으로한 임상결과이다. 총 240개의 타액 표본들은 마케도니아(Macedonia), 스코프에(Skopje)에 위치한 St Kiril- Metodi 치과대학병원에서 환자 80명으로부터 얻었다. 표본들은 사전의 파라핀 저작(씹기)법에 의해 타액을 자극하여 얻어졌으나, 타액의 pH의 결정을 위해서 다른 자극은 사용되지 않았다. 치아우식 집단의 타액 1 ml에서 S. mutans는 100%의 confluent growth (CFU > $10^6$와 $10^4-10^5$) 였으나, Lactobacillus spp.는 78.3%였다. 대조표본 집단(건강하고 손상되지 않은 치아를 가짐)에서, confluent growth (CFU > $10^6$와 $10^5$)를 가지는 colony는 발견되지 않았다. 이와 달리, 두 집단 모두(60 + 20)에서 타액의 pH와 타액의 완충력으로부터 얻어진 결과는 상호연관이 있었다. 치아우식집단에서, 타액의 pH 결과치는 약산성(5.90 - 6.50)이었고, 타액의 완충력 역시 매우 낮았다(0.7ml 이하). 한편, 대조표본 집단에서, 타액의 pH는 중성(pH 7.01 - 7.7)이었고 타액 완충력은 높았다(1ml 이상). CRT-bacteria 시험법으로부터 얻은 타액 1 ml내($10^5$ CFU 이상)의 S. mutans와 Lactobacillus spp.의 증가된 수는 타액의 산성과 약산성 pH의 결과처럼 치아우식위험을 증가시켰다. 따라서, 타액 pH법과 완충력 측정법은 치아우식 위험을 예측 할 수 있으며, 치아우식 예방을 위해 유용한 측정법으로 사용될 수 있을 것으로 사료된다.

• KSBB Journal
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• 제28권1호
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• pp.24-30
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• 2013

Dissolved oxygen, pH and cell concentration have been online monitored in cultivation processes with Escherichia coli by using a $MABOOMS^{TM}$ (microplate-based bioreactor with optical online monitoring systems). Fluorescent sensing membranes containing Ru ${(dpp)_3}^{2+}$ or HPTS were prepared with GA sol-gel matrix and coated into a well of a 24-well microplate. Fluorescence intensity was measured and correlated to the dissolved oxygen or pH. Cell concentrations were also online monitored by measuring optical reflectance at 650 nm. A well of a 24-well microplate could also be divided into 4 parts, each of which was coated with fluorescent sensing membranes for the detection of dissolved oxygen or pH. The 24-well microplate coated with fluorescent sensing membranes or a 4-divided sensing membrane. was used to online monitor the dissolved oxygen, pH and cell concentration during E. coli cultivations. The online monitoring results showed the characteristics of cell growth in cultivation processes very well.

• 한국융합학회논문지
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• 제9권7호
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• pp.149-154
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• 2018

본 논문은 Lavender, Tea tree, Eucalyptus, Lemongrass 4종의 천연에센셜오일의 Streptpccous mutans 에 의한 치석형성억제 효과에 대하여 연구해 보고자 하였다. Streptpccous mutans 에 의한 치석형성 억제 활성 측정결과인 Lavender 에센셜 오일의 MAC (Minium anti-adhesive concentration, 최소부착저지 농도)가 1.0 % 이고 Tea tree 에센셜 오일, Eucaliptus 에센셜 오일, lemongrass 에센셜 오일의 MAC는 0.5 % 로 나타났다. 에센셜오일의 농도를 달리하여 Streptpccous mutans와 혼합한 배양액을 항온조에서 배양한 후 용액의 pH를 측정하여 최소부착 저지농도 이하에서 산의 생성으로 pH가 낮아진 것을 확인할 수 있었고, 이 결과는 에센셜 오일이 Streptpccous mutans 에 의한 산의 생성을 억제하는 효과가 있다는 것이다. 이러한 결과들로부터 천연에센셜오일 중 특히 Tea tree, Eucalyptus, Lemongrass는 치석생성을 억제하는 천연소재로 구강관리 제품개발에 활용할 수 있는 가능성을 확인할 수 있었다.

• KSBB Journal
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• 제15권1호
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• pp.1-8
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• 2000

The diffusion effect of simulated gastric juices into the various alginate vessel containing each biopolymer such as 0.3% soluble starch, whey, corn starch, agar, locust bean gum, guar gum, gum arabic, pectin, gelatin and 0.15% xanthan gum was tested by measuring the change of pH in the vessel. The degree of viability of bifidobacteria entrapped in each bead containing biopolymers was corresponded with the degree of diffusion inhibition of hydrogen into the each vessel. Therefore, The determination of diffusion inhibition of simulated gastric juices into the various vessel by measuring the change of pH in the vessel may be effectively used as the simple method to select the optimal entrapment lattice for the improvement of bifidobacteria viability. Bifidobacteria entrapped in alginate bead containing 0.15% xanthan gum whose lattice showed the lowest hydrogen diffusion were more significantly tolerant against bile salts and hydrogen peroxide than untrapped bifidobacteria. It was also observed that the viability of bifidobacteria entrapped in bead was nto nearly changed in milk adjusted pH 4.5 with organic adids at $4^{\circ}C$ for 10 days. Therefore, use of alginate containing 0.15% xanthan gum as a cell matrix for entrapping bifidobacteria was expected to improve the viability of bididobacteria in fermented milk products and develop the high value-added products.