• Restorative Dentistry and Endodontics
• /
• v.16 no.1
• /
• pp.87-105
• /
• 1991

The purpose of this experiment was to measure the leaking and solubility of commonly used dental restorative materials - Silux plus (CS), Hi-pol (CH), Clearfil F-II, Fissureseal (FS), Glass-Ionomer cement Fuji Type II (GI), Amalgam Cavex 68 (AM), Zinc Phosphate Cement (ZP) and gutta-percha (GP) and investigate the relation between the solubility and marginal leakage. Disc-shape specimens were fabricated with each material and dipped into deionized water, 0.01M lactic acid and 0.005M KOH solution, thus the total ionic concentrations in each solution was measured with ion chromatograph after 1, 3, and 7 days, respectively. For the solubility test, each specimen was immersed in 0.001M and 0.01M lactic acid for 24 hours, respectively and total weight loss was calculated. Also, Zn leaking through the margin of restorations was measured. The obtained results were as follows: 1. The amounts of eluted ion from the eight materials were most in 0.01M lactic acid and least in deionized water. 2. Of the eight materials, the fluoride release was greatest for glass ionomer cement (GI) in 0.01 M lactic acid after 7 days. 3. In analysis of the divalent cation, Mg was eluted most for zinc phosphate cement (ZP) and Ca for Clearfil F-II (CF) in 0.01M lactic acid after 7 days. 4. In analysis of transition metals, Cu and Zn were detected only. 5. The solubility rate of eight materials was greater in 0.01M lactic acid than in 0.001M for 24 hours, for zinc phosphate cement (ZP) the rate was greatest (5.4%) in 0.001M lactic acid, and amalgam least (0.01%). 6. The Zn concentration of restorative material with Z.P.C base was greater in 0.01M lactic acid than in 0.001M lactic acid.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.10
• /
• pp.1372-1376
• /
• 2011

The content of Ca in milk exceeds the typical saturation level of Ca salts, which is necessary for neonate growth. This calcium is distributed between the casein micelles in the colloidal and aqueous phases. Information on the properties of calcium activity in the aqueous phase is limited compared with that on the properties of bound or sequestrated calcium. The objectives of this study were to evaluate the changes in calcium activity in fresh milk using an ion-selective electrode and to assess the relationship between calcium activity and milk production in hot season. Milk samples collected from 10 cows at the National Agricultural Research Center for Kyushu Okinawa Region in June to October (Min-Max: 7.2-$35.2^{\circ}C$, 24.3-100% RH) were analyzed on total calcium concentrations and calcium activity. We observed that the rectal temperature of the cows increased according to elevation of ambient temperature but that the pH of the collected milk ($6.61{\pm}0.01$ (Mean${\pm}$SEM)) was not significantly influenced by rectal and ambient temperature. Total calcium concentrations and calcium activity in fresh milk decreased in July (Min-Max: 21.1-$33.5^{\circ}C$, 48.9-100.0% RH) compared with the values after August (Min-Max: 18.1-$35.0^{\circ}C$, 26.5-96.2% RH) (p<0.05); however, there was no significant correlation between the two parameters. The ratio of calcium activity to total calcium concentration decreased after August compared with the values in June and July (p<0.05). The calcium activity in fresh milk was positively correlated with milk yield (r = 0.45, p<0.01) and negatively correlated with milk lactose content (r = -0.53, p<0.01). These results suggest that the calcium activity in milk could be affected by ambient temperature and might be associated with milking production in hot season.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.12
• /
• pp.2227-2238
• /
• 2000

The interfacial features of suspension system made of $CaCO_3$ particles have been investigated for the purpose of designing its effective treatment process. For the examination of variation of electrokinetic potential as a function of pH. the value of potential was observed to shift in the negative direction, which was thought to be due to the adsorption of hydroxide ion on the particle surface. Adsorption of surfactant on suspended particles resulted in the change of surface charge and shift in electrokinetic potential, which was dependent upon the sign of head charge and concentration of surfactant. Addition of inorganic salts affected stability of suspension greatly and sedimentation rate of suspension was influenced by the electric valence and amount of ions produced by dissolution of inorganic coagulants. DLVO theory made it possible to construct a energy profile diagram and a close correlation was found between experimental result and theoretically derived consequences. Non-specific adsorption of indifferent electrolyte resulted in the compression of electrical double layer and specific adsorption induced the shift of IEP and PZC in the opposite direction.

• Journal of Life Science
• /
• v.13 no.5
• /
• pp.618-625
• /
• 2003

Investigations were carried out to optimize the culture conditions for the production of xylanase by Paenibacillus sp. DG-22, a moderately thermophilic bacterium isolated from timber yard soil. Xylanase production showed a cell growth associated profile. Xylanase activity was found only in the culture supernatant, while $\beta-xylosidase$ activity was mainly associated with the cells. The formation of xylanase activity was induced by xylan and repressed by glucose and xylose. The production profile of xylanase was examined with various commercial xylan and maximum yield was achieved with 0.1∼ 0.5% birchwood xylan. Among various nitrogen sources tested, yeast extract was optimal for the production of xylanase. The xylanase activity was inhibited by $Co^{2+},\; Cu^{2+},\; Fe^{3+},\; Hg^{2+}\;$ and$\;Mn^{2+}$ ions while $Ca^{2+},\; Mg^{2+},\; Ni^{2+},\; Zn^{2+}$ions and DTT stimulated xylanase activity Mercury (II) ion at 5 mM concentration abolished all the xylanase activity. The predominant products of xylan-hydrolysate were xylobiose, xylotriose, and higher xylooligo-saccharides, indicating that the enzyme was an endoxylanase.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.3
• /
• pp.365-372
• /
• 2004

Two simple, rapid and sensitive spectrophotometric methods for the determination of three fluoroquinolones, namely levofloxacin, norfloxacin and ciprofloxacin have been performed either in pure form or in their tablets. In the first method, levofloxacin and norfloxacin are directly treated with bromocresol green (BCG) in dichloromethane while ciprofloxacin is allowed to react with the same dye in aqueous acidic buffer. Highly yellow colored complex species were formed instantaneously in case of levofloxacin and norfloxacin or after extraction into dichloromethane for ciprofloxacin. The formed complexes are quantified spectrophotometrically at their absorption maxima at 411 nm for levofloxacin and 412 nm for norfloxacin and ciprofloxacin. The second method involves the reaction of levofloxacin with ${\rho}$-chloranilic acid ( ${\rho}$-CA) and norfloxacin with tetracyanoethylene (TCNE) in acetonitrile to give complexes with maximum absorbance at 521 and 333 nm for the two drugs, respectively. Adopting the first procedure, calibration graphs were linear over the range 1- 20 ${\mu}g\;mL^{-1}$ with mean percentage recoveries of 100.41 ${\pm}$ 0.72, 99.99 ${\pm}$ 0.54 and 100.23 ${\pm}$ 0.91 for the theree drugs, respectively. For the second procedure, the concentration ranges were 15-250 ${\mu}g\;mL^{-1}$ for levofloxacin using ${\rho}$-CA and 0.8-16 ${\mu}g\;mL^{-1}$ for norfloxacin using TCNE with mean percentage recoveries of 99.88 ${\pm}$ 0.45 and 100.26 ${\pm}$ 0.68 for the two drugs, respectively. The proposed methods were successfully applied to determine these drugs in their tablet formulations and the results compared favorably to that of reference methods. The proposed methods are recommended for quality control and routine analysis.

• Journal of Environmental Science International
• /
• v.13 no.12
• /
• pp.1067-1078
• /
• 2004

Atmospheric particulate matters were collected by 8-stage non viable cascade impactor from October 2002 to August at Jeju City. Eight water-soluble ionic components $(Na^+,\;NH_{4}_{+},\;K^+,\;Ca{2+},\;Mg^{2+},\;CI^-,\;NO_{3}^-\;and\;SO_{4}^{2-})$ were analyzed by Ion Chromatography. The concentration of particulate matters and eight water-soluble ionic components were determined to investigate their size distributions. Particulate matters exhibited a tri-modal distribution with peak value around $0.9,\;4.0{\mu}m\;and\;9.5{\mu}m.$ In summer, the last peak value was lower than other season values likely due to particulate matter scavenged by rain water. Four ionic components $(Na^+,\;Ca^{2+},\;Mg^{2+}\;and\;CI^-)$ exhibited a bi-modal distribution in the coarse mode whereas three ionic components $(NH_{4}^+,\;K^+\;and\;SO_{4}^{2-})$ in the fine mode, with maximum peak value around $0.9{\mu}m.\;NO_{3}^-$ was found in both the coarse and the fine mode. The enrichment factor (E.F.) of each ionic components was calculated. Based upon E.F., it is considered that $Na^+,\;CI^-,\;and\;K^+$ in coarse paricle mode were delivered form oceanic source, but other components might have other source origins.

• Journal of Environmental Science International
• /
• v.24 no.8
• /
• pp.981-992
• /
• 2015

This study is mainly focused on micellar effect of tetradecyltrimethyl ammonium bromide(TTABr) solution including alkylbenzimidazole(R-BI) on dephosphorylation of diphenyl-4-nitrophenylphosphinate(DPNPIN) in carbonate buffer(pH 10.7). Dephosphorylation of DPNPIN is accelerated by $BI^{\Theta}$ ion in $10^2$ M Carbonate buffer(pH 10.7) of $4{\times}10^{-4}$ M TTABr solution up to 80 times as compared with the reaction in Carbonate buffer by no benzimidazole(BI) solution of TTABr. The value of pseudo first order rate constant($k_{\psi}$) of the reaction in TTABr solution reached a maximum rate constant increasing micelle concentration. The reaction mediated by $R-BI^{\Theta}$ in micellar solutions are obviously slower than those by $BI^{\Theta}$, and the reaction rate were decreased with increase of lengths of alkyl groups. It seems due to steric effect of alkyl groups of $R-BI^{\Theta}$ in Stern layer of micellar solution. The surfactant reagent, TTABr, strongly catalyzes the reaction of DPNPIN with R-BI and its anion($R-BI^{\Theta}$) in Carbonate buffer(pH 10.7). For example, $4{\times}10^{-4}$ M TTABr in $1{\times}10^{-4}$ M BI solution increase the rate constant($k_{\psi}=99.7{\times}10^{-4}1/sec$) of the dephosphorylation by a factor ca. 28, when compared with reaction($k_{\psi}=3.5{\times}10^{-4}1/sec$) in BI solution(without TTABr). And no TTABr solution, in BI solution increase the rate constant($k_{\psi}=3.5{\times}10^{-4}1/sec$) of the dephosphorylation by a factor ca. 39, when compared with reaction ($k_{\psi}=1.0{\times}10^{-5}1/sec$) in water solution(without BI).

• Economic and Environmental Geology
• /
• v.31 no.1
• /
• pp.11-20
• /
• 1998

The effects of the major cations ($Ca^{2+}$, $Mg^{2+}$, $K^+$, $Na^+$), complex-forming anions ($SO_4{^{2-}}$, $HCO_3{^-}$), and solution pH on the adsorption of $^{137}Cs$ and $^{90}Sr$ by kaolinite in groundwater chemistry were investigated. Three-dimensional Kd modelling designed by a statistical method was attempted to compare the relative effect among hydrated radii, charge and concentration of competing cations on the adsorption of Cs and Sr. The modelling results indicate that the hydrated radii of competing cations is the most important factor, and then their charges and concentrations are also important factors in order. The property of zeta potential of kaolinite particles was discussed in terms of the amphoteric reactions of a kaolinite surface affecting the adsorption of Cs and Sr. The ionic strength of competing cations on the adsorption of Cs and Sr exerts a greater effect than the solution pH. The sorption behaviour of Sr on kaolinite is also highly dependent on the concentration of bicarbonate. The speciation of Sr and the saturation state of a secondary phase were thermodynamically calculated by a computer program, WATEQ4F. This indicates that the change in solution pH with the concentration of bicarbonate and the precipitation of a strontianite ($SrCO_3$) are major factors controlling Sr adsorption behaviour in the presence of bicarbonate ion.

• Food Science and Biotechnology
• /
• v.17 no.1
• /
• pp.46-51
• /
• 2008

The objective of this study was to investigate antioxidant activities of freeze-dried, main root, and fine root of ginseng (Panax ginseng CA. Meyer), which were extracted with various solvents including ethanol, methanol, and water. Ethanol extracts in both parts showed the most powerful scavenging activities against DPPH radicals. Especially, ethanol extract of fine root had higher reducing power and antioxidant capacity than that of main root. The highest antioxidant activity in linoleic acid emulsion system was also observed in fine root extracted with ethanol, followed by methanol and water. Both ferrous ion chelating activity and ferric reducing antioxidant power (FRAP) of extracts were increased with the increase of extracts concentration. These results suggest that ethanol extract of fine root of ginseng has the most effective antioxidant capacity compared to the methanol and water extracts tested in the present study. Thus it can be applied for the effective extraction of functional material from ginseng for the usage of pharmaceutical and/or food industries.

• Microbiology and Biotechnology Letters
• /
• v.23 no.4
• /
• pp.432-438
• /
• 1995

The intracellular alginase from Vibrio sp. AL-145 was purified by ion chromatography on DEAE-Cellulose column, Q-Sepharose column, and gel filtration on Sephadex G-100 column. The optimum pH and temperature for the activity of the purified intracellular enzyme were 8.0 and 37$\circ$C, respectively. The enzyme was stable at the pH range of 7.5-8.5, and at 30$\circ$C for 30 min. The molecular weight of the intracellular enzyme was estimated to be about 23, 000 daltons by SDS-polyacrylamide gel electrophoresis. NaCl was required for enzyme activity and the optimum concentration was 0.5 M. The activity of intracellular enzyme was inhibited by Co$^{2+}$, Hg$^{2+}$, Zn$^{2+}$, 0-phenanthroline, $\rho$-CMB, EDTA and iodoacetate, and stimulated by Ca$^{2+}$, L-cysteine and 2-mercaptoethanol. This enzyme was an alginase specifically degrading alginic acid.