• Restorative Dentistry and Endodontics
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• v.23 no.2
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• pp.710-717
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• 1998

The pH changes in 3 cavities prepared at the facial inner dentin and lingual outer dentin of the cervical portion and apical portion of roots filled with calcium hydroxide containing sealers were investigated. 50 extracted permanent teeth with single canal were instrumented with step-back method. An irrigant of 5% NaOCl was used between files. Then 3 small cavities were prepared. The cavity of apical portion and inner dentin cavity of coronal portion was cut a distance of about 1.0mm from the canal wall and outer dentin cavity of coronal portion was cut to a depth of about 0.5mm from root surface. 10 teeth of control group was not filled. 20 teeth were not flushed with 17% EDTA before using root canal sealers and then divided into 2 groups obturated with Sealapex and Apexit. The remaining 20 teeth were flushed with 17% EDTA and 5% NaOCl to remove smear layer and divided into 2 groups obturated with Sealapex and Apexit. The pH change of the dentin in each cavity was measured at 0, 1, 3, 5, 7, 15, 30 days with pH microelectrode(WPI Co., USA). The results were as follows: 1. The groups obturated with Sealapex and Apexit(calcium hydroxide based-sealers) have no increase in the pH level at root dentin. And there is no significant difference in pH level between groups obturated with Sealapex and Apexit(P>0.05). 2. Differences in pH levels between the treated and untreated groups with EDTA were not significant(P>0.05). 3. There is no significant difference in pH level between apical and cervical dentin, inner and outer dentin throughout the duration of the experiment(P>0.05).

• Korean Journal of Food Science and Technology
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• v.39 no.5
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• pp.506-514
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• 2007

In this study, carrot juice was treated with high voltage pulsed electric fields (PEF) and the changes in its physical and chemical properties during storage at $4^{\circ}C$ and $25^{\circ}C$ were investigated. The sterility fur bacteria, yeast and mold in carrot juice increased with increasing electric field strength and treatment temperature. While yeast and mold were completely inactivated at 65kV/cm with a treatment time of $200{\mu}s$ in a continuous PEF treatment system, bacteria were reduced by four log cycles. The results also showed that square wave pulse treatment was more effective for inactivating microorganisms than exponential decay pulse, and this effect was more apparent for carrot juice of lower pH. Although we observed significant changes in physical and chemical properties such as soluble solid content, pH, acidity, color, and carotene retention when the PEF treated samples were stored at the ambient temperature $(20^{\circ}C)$, no significant physical and chemical changes were found at the cold storage temperature $(4^{\circ}C)$ during 28 days of storage. The results indicate that the PEF treated carrot juice is appropriate for commercial refrigerated storage.

• Journal of Sericultural and Entomological Science
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• v.52 no.1
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• pp.6-9
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• 2014

This study was for the investigation of the stability of purified bee venom (PBV) during the treatment in the pH range from pH2 to pH9 for 24 hours, respectively. Changes of components and physiological functionalities in PBV were by evaluated silver staining, and melittin contents were measured by liquid chromatography. The antimicrobial activity against bacteria by minimum inhibitory concentration (MIC) and effect of the cell regeneration were measured by 3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl tetrazolium bromide (MTT) assay using human dermal fibroblast (HDF) cell. The main proteins such as melittin and phospholipase $A_2$ showed no characteristic changes. The antimicrobial activity and effect of cell regeneration showed no difference from pH2 to pH9. From this study, we suggest that components and physiological functionalities of PBV against treated pH were kept stability at from pH2 to pH9.

• Journal of the Korean Wood Science and Technology
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• v.35 no.4
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• pp.21-28
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• 2007

To analyze the changes in pH and elemental content ratio of wood charcoal and in FT-IR spectra of their surfaces, wood charcoals carbonized from Pinus koraiensis were used. pHs of wood charcoals carbonized from Pinus koraiensis at 300 and $400^{\circ}C$ were 5-27 and 6.80, respectively, whereas they were between 9.25~10.35 for the wood charcoals manufactured between $500{\sim}900^{\circ}C$ From the changes in the elemental ratios of Pinus koraiensis wood charcoal by increasing carbonization temperature, carbon (C) contents increased by elevating the carbonization temperature with the decreasing in content ratios of O and H. The largest changes in the ratio was found between the carbonization temperature 400 and $500^{\circ}C$. Ratios of C, O, H of the wood charcoal manufactured at 300 and $400^{\circ}C$ were 67.7, 28.9, 3.0% and 72.2, 24.9, 2.5%, respectively, while those at $500{\sim}900^{\circ}C$ were between 83.3~90.5, 13.6~9.0, 2.7~0.3%. The surface functional groups of Pinus koraiensis wood charcoals were determined by comparison of FT-IR spectra of the wood powder and the wood charcoal carbonized with the wood powder. The functional groups on the surface of wood charcoals carbonized at 300 and $400^{\circ}C$ were considered to be acidic groups like Lactone, Lactol, Carboxylic acid, Carboxylic anhydride, whereas Pyrone types could be the major functional groups for the wood charcoals carbonized between 500 and $900^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1811-1814
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• 2009

The effect of fermentation with mixed cultures of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus on the microbiological characteristics of oat extract was investigated. Changes in pH, titratable acidity and viable cell populations indicated that growth was better in mixed cultures of L. delbrueckii subsp. bulgaricus and S. salivarius subsp. thermophilus. Growth of S. salivarius subsp. thermophilus in oat extract was more rapid than growth of L. delbrueckii subsp. bulgaricus. Cooperative interaction between two cultures during fermentation of oat extract as in yogurt from cow's milk was observed, but the intensity was relatively weak.

• Journal of the Korean Society of Visualization
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• v.8 no.4
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• pp.38-42
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• 2010

Ion concentration polarization is an electrokinetic phenomenon which occurs in membrane systems, such as in an electrodialysis and fuel-cell system. But the phenomenon is not fully understood because hydrodynamics, electrokinetics and electrochemistry are coupled with each other. Here, we report that there occurs a change of pH value of buffer solution in concentration polarization phenomenon. To visualize the change of pH, the litmus solution which is one of the pH indicators was used. It is conjectured that the pH of solution changes because hydrogen ions were concentrated in cathodic side and hydroxide ions were concentrated in anodic side. We anticipate that this work may contribute to the fundamental understanding on the ion concentration polarization phenomenon.

• Journal of Fashion Business
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• v.14 no.2
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• pp.138-150
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• 2010

In the dyeing of cotton and silk fibres using Caesalpinia sappan, the effects of pH changes of the Caesalpinia sappan dye liquor on the color were examined. In order to adjust the pH of the Caesalpinia sappan dye liquor, Schisandra chinensis extract and carboxylic acid were used for acidic condition, lye and the NaOH aqueous solution were used for alkaline condition. By introducing the dyeing method of pH adjustment, firstly, the effect on the reddish color inherent to the Caesalpinia sappan was examined. At the same time, the manifestation of the yellow color, which affect the manifestation of the red color greatly, was examined in detail quantitatively. By dyeing the cotton and silk fabrics, the inherent relationships established between the pH hanges and the fibre characteristics were sought to be examined.

• Journal of Sericultural and Entomological Science
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• v.39 no.1
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• pp.67-72
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• 1997

As a condition for obtaining the silk I type crystal that has stability and high reproducibility, after dissolving silk fibroin crystalline part (Fcp), the changes of recrystallized crystal structure according to dialytic pH were examined by x-ray diffraction and differential thermal analysis. The Fcp was obtained from the aqueous solution of silk fibroin enzymatic proteolyzed by chymotrypsin. The crystal structure of Fcp showed silk II type. When the Fcp was dissolved by 10M LiBr aqueous solution, the Fcp1 showed the silk II type at pH 9. However, besides the silk II type, the silk I type structure begins to appear at pH 8 and only the silk I type structure was found below pH 6. On the other hand, the Fcp2 that calcium chloride was used in the dissolution found only the silk I type crystal structure below pH8.

• Food Science of Animal Resources
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• v.25 no.3
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• pp.310-315
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• 2005

The changes in pH, temperature, R-values and ${\mu}-calpain$ and its inhibitor activity of M. longissimus from Hanwoo steer were investigated at 1, 3, 9 and 24h postmortem. The pH and temperature of M. longissimus were significantly (p<0.05) decreased during 24h postmortem time, and were 6.50 and $31.99^{\circ}C$, respectively, at 3h postmortem. $R_{248}\;and\;R_{250}$ were increased, but $R_{258}$ was decreased after 9h postmortem time (p<0.05). Calpain I and calpastatin activity were decreased after 3h and 9h postmortem time, respectively (p<0.05). pH and temperature showed high positive correlations with $R_{258}$ (r=0.967 and r=0.970, respectively), calpain I (r =0.956 and r=0.954, respectively) and calpastatin (r=0.978 and r=0.986, respectively) but had high negative correlations with $R_{248}$ (r=-0.982 and r=-0.973, respectively) and $R_{248}$ (r=-0.983 and r=-0.976, respectively). from these results, the change of postmortem metabolism of M. longissimus from Hanwoo steer likely occurred after 9h postmortem time. However, the further study on the establishment of metabolism from Hanwoo between postmortem 3h and 9h are necessary to produce Hanwoo beef with high acceptance in meat quality.

• Journal of Korean Society of Forest Science
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• v.82 no.4
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• pp.337-346
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• 1993

Experiments were performed to find out the effects of simulated acid rain(SAR) of pH 4.0 or pH 2.5 for 12 weeks on stomatal resistance, wettability and anatomical changes in Quercus acutissima and Ginkgo biloba seedlings. As a control, distilled water with a pH 6.5 was also sprayed. Stomatal resistance of Q. acutissima and of G. biloba remarkably increased after exposure to SAR. SAR increased the wettability of Q. acutissima leaves measured with water blue solution and of G. biloba leaves measured by leaf contact angle method. Anatomical changes in the leaves of Q. acutissima affected by SAR were the partial damage of epidermis and parenchymatous cells. Scanning electron microscopical observation showed that the number of trichomes in the leaves of Q. acutissima treated with SAR markedly decreased and the erosion of epicuticular wax was significant. No distinct damage was found in the G. biloba leaves at pH 4.0, while epidermis and vascular tissue were collapsed at pH 2.5. No significant alteration of surface structures in this tree species was observed.