• Korean Journal of Microbiology
• /
• v.40 no.4
• /
• pp.313-319
• /
• 2004

The distribution and characteristics of acidotolerant heterotrophic and naphthalene-degrading bacteria were investigated in two forest areas, one near Ulsan petrochemical industrial complex (Sunam) and the other in countryside (Daeam). Average values of soil pH at Sunam and Daeam were 3.8 and 4.6, respectively. When het­erotrophic and naphthalene-degrading bacteria were enumerated by most probable number (MPN) procedures at Sunam, the median values of heterotrophs growing at pH 7.0 and pH 4.0 were $5.3{\times}10^7\;and\;3.3{times}10^7$ MPN/g, whereas those of naphthalene-degraders were $5.6{\times}10^4\;and\;4.0{times}10^5$ MPN/g, respectively. While the medians of heterotrophs at Daeam were larger than those at Sunam, the concentrations of naphthalene-degraders were higher at Sunam compared to those at Daeam. From the MPN tubes and enrichment cultures, we obtained 17 isolates of naphthalene-degraders which were identified as Sphingomonas paucimobilis, Brevundimonas vesic­ularis, Burkholderia cepacia, Ralstonia pickettii, Pseudomanas fluorescens, and Chryseomonas luteola. Among them, 6 isolates showed higher naphthalene-degrading activity on minimal media of pH 4 compared to pH 7, whereas the extent of growth was not greater at pH 4 than at pH 7 when they were inoculated on nutrient-rich media. It is plausible that the pH may affect naphthalene-degrading activity of the isolates by changing fatty acid composition of bacterial membrane.

• Natural Product Sciences
• /
• v.10 no.6
• /
• pp.302-305
• /
• 2004

The lipase and phospholipase activities of meals of resting seeds of C. roxburghianum were studied at different temperatures, solvents and pH. Both the enzymes showed the maximum activities at $40^{\circ}C$ and in n-heptane used as solvent. However, lipase showed maximum activities at two different pH, one at pH 5 (acidic) and other at pH 8 (alkaline) whereas phospholipase showed only one pH optimum at pH 8. During the course of germination, the lipase showed an increase whereas reverse was the case with phospholipase.

• Archives of Pharmacal Research
• /
• v.17 no.4
• /
• pp.231-235
• /
• 1994

Fluorenecarboxaldehyde hydrazone 9FCH)was synthesized as a new fluorescent reagent for the determination of acidity. FCH had no fluorescence in itself, however, it strongly fluoresced under acidic conditions at excitation maximum of 392 nm and emission maximum of 447 nm, respectively. It showed good correlation with pH in the range from pH 0.60 to pH 3.60 in strong acids. As an application, the acidity of gastric juice in rats and humans was determined. In comparision with pH-metry, the acidity measured by the developed method showed generally increased values of about 0.7-1.3 unit and 0.8-1.2 unit in rats and humans, respectively. However, these results had statistically close correlation with those of pH-metry and the correlation coefficients were 0.887 in rats and humans between two methods.

• Journal of Korean Society on Water Environment
• /
• v.18 no.2
• /
• pp.169-187
• /
• 2002

The effects of important parameters such as reaction time and pH on the Fenton's process were evaluated using a batch reactor. It was proven that organic materials and heavy metals in leachate could be successfully removed by Fenton's reagent. Favorable operation conditions were investigated. It was observed that the reaction between ferrous iron and hydrogen peroxide with the production of hydroxyl radical was almost complete in 10 minutes. That is, the oxidation of organic materials by Fenton's reagent was so fast that it was complete in 30 minutes with batch experiments. With the formation of carbonic acid, pH of the batch reactor decreased to favorable acidic conditions without acid addition. The oxidation of organic materials in the leachate showed a pH dependence and was most efficient in the pH range of 2-3.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.11
• /
• pp.1180-1185
• /
• 2005

Iron sand, having iron as a major component, was applied in the treatment of synthetic wastewater containing Cu(II) or Pb(II). To investigate the stability of iron sand at acidic condition, dissolution of Fe and Al was studied with variation of solution pH ranging from 2 to 4.5. Iron concentration in the extracted solution was below the emission regulation of wastewater even at a strong acidic condition, pH 2. Although an important concentration of aluminum was extracted at pH 2, the dissolution greatly decreased above pH 3. This stability test suggests that application of iron sand has little problem in the treatment of wastewater above pH 3. Adsorption capacity of Cu(II) and Pb(II) onto iron sand was investigated in a batch and a column test. In case of Cu(II), rapid adsorption was noted, showing 50% removal within 2 hrs, and then reached a near complete equilibrium after 24 hrs. Adsorption was favorable at higher pH in each metal ion and showed a near complete removal above pH 6, indicating a typical cationic-type adsorption. From the adsorption isotherm obtained with variation of the concentration of each metal ion, the maximum adsorption capacity of Cu(II) and Pb(II) was identified as 2,170 mg/kg 및 3,450 mg/kg, respectively.

• Proceedings of the Zoological Society Korea Conference
• /
• 1995.10b
• /
• pp.289.2-289
• /
• 1995

No Abstract, See Full Text

• Journal of Pharmaceutical Investigation
• /
• v.18 no.3
• /
• pp.133-137
• /
• 1988

In vitro studies were performed on the interaction of indomethacin with cholestyramine, a hypocholesterolemic substance. Cholestyramine showed a marked affinity for indomethacin among tested acidic drugs and the intensity of adsorption was dependent on pH, temperature and sodium chloride. Moreover, the combination of indomethacin with some acidic drugs that formed complexes with cholestyramine, considerably inhibited the adsorption of indomethacin on the resin.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.05a
• /
• pp.96-102
• /
• 2002

This paper was studied on the wear-corrosion behavior of ductile cast iron in the acidic environment. In the dry atmosphere and variety of pH solution, wear-corrosion characteristics and friction coefficient of GCD 60 with various sliding speed and distance were investigated. And electrochemical polarization test of GCD 60 was examined in the environment of various pH value. The main results are as following : In the dry atmosphere, boundary friction appears below nearly 5 $kg_{f}$ of contact load, and it is considered that solid friction occurs over nearly 5 $kg_{f}$ of contact load. As pH value becomes low, wear-corrosion loss in the aqueous solution increases. As the corrosion environment is acidified, corrosion potential of GCD 60 becomes noble, polarization resistance becomes low, and corrosion current density increases.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.3
• /
• pp.412-417
• /
• 2001

Sodium alginate was used to immobilize Bifidobacterium breve ATCC 15700 cells. The ability of the Ca-alginate beads to protect the B. breve ATCC 15700 was evaluated under different conditions including alginate concentration, bead size, pH, hydrogen peroxide, and storage period. The survival of the B. Breve ATCC 15700 was estimated in pasteurized yogurt, containing either the immobilized or free cells, throughout the storage period. The survival cells in bead after exposure to acidic solution (pH 3.0) increased with increase of both the alginate gel concentration and bead size. Also, immobilized cells in alginate bead were more resistant than the free cells to hydrogen peroxide, storage period, and the environment inside yogur. When retreated beads with skim milk and nonretreated beads were tested in acidified pH 3.0 TPY media including acetic and lactic acid, the number of viable cells in the retreated bead was approximately 10-fold higher than that of nonretreated beads. This suggests that the skim milk operated as a material decreasing the diffusion of acid and hydrogen perosicde into alginate gels. From this research, it was found that yogurt itself supported immobilized cells with an improved protection from the extreme acidity in yogurt.

• YAKHAK HOEJI
• /
• v.18 no.2
• /
• pp.133-144
• /
• 1974

The metal indicator, acidic azo dyes NN, EBT and Calcon are utilized to analyse quantitatively chlorpheniramine, tripelenamine and diphenhydramine forming insoluble ion pair in aqueous solution at proper pH values between the acidic azo dyes and the sample molecules, these compexes are extracted by organic polar solvents, and organic layer is determined spectrophotometrically. Generally, the absorption maxima of the complexes are shifted to longer wavelengths compare to the absorption maxima of the dyes themselves. The binding ratio of the ion pair forming complex molecules in chloroform soln, are as follows ; NN-antihistamines (chlorpheniramine, tripelennamine, diphenhydramine) are NN-1 to antihisamine-1, EBT-antihistamines are EBT-2 to antithistamines a and Calcon-antihistamines are Calcon-3 to antithistamines-1. These coomplexes in chloroform soln. are very stable, and show higher absorbance than the other organic polar solvents. The binding state of complexes were presumed intermolecular hydrogen bond by their infrared spectra. In the mixture solution of three samples, the aqueous phase is buffered at pH 1.0, and benzene is used to extract ion pair of diphenhydramine EBT complex selectively. At pH 1.0 of aqueous layer, Calon-diphenhydramine complex is also extracted selectively by benzene. However, in this case very small amount of chlorpheniramine-calcon calcon simultaneously. The binding state of diphenhydramine-EBT and diphenhydramine-calcon in benzene are smae as the complexes in chloroform. But the absorption maxima of the complexes in benzene are shifted to shorter wavelenlgths than the complexes in chloroform.