• Korean Journal of Soil Science and Fertilizer
• /
• v.31 no.3
• /
• pp.266-270
• /
• 1998

The identification of soil P level that exceed crop requirement is a prerequisite in implementing sustainable management of fertilizer and manure P to prevent soil and freshwater from contamination. To investigate the relationship between 0.01M $CaCl_2$ soluble P, and available P and P sorption capacity of 40 soils, P content and P sorptivity were analyzed. Single linear relationship revealed the dependence of 0.01M $CaCl_2-P$ on available P($r^2=0.479$), bioavailable P($r^2=0.281$), P sorption($r^2=-0.465$) and P absorption coefficient($r^2=-0.056^{NS}$). Thus available P as $P_2O_5$(AVP) and P sorption (PS) were most important factors in determining the concentration of 0.01M $CaC1_2-P$($CaC1_2-P$). In multinomial equation related $CaC1_2-P$ with AVP and PS, the determination coefficient was improved to 0.745. The logarithm of $CaC1_2-P$ was linearly related to AVP/PS. Consequently, the equation, $0.01M\;CaCl_2-P=0.1284e^{0.3288AVP/PS}$ could be suggested to estimate the concentration of P in 20mL of 0.01M $CaCl_2$ solution containing 2g of soil shaken for 17 hours.

• Applied Biological Chemistry
• /
• v.20 no.1
• /
• pp.88-94
• /
• 1977

A laboratory study was made of liming on the extractability of phosphate added to the uncultivated acid soils differing in clay content. The experiments were conducted with different rates of calcium carbonate and triple superphosphate at field capacity and 50% field capacity. The concentration of extractable phosphate was greatly reduced by simultaneous addition of calcium carbonate in the loam soil. When samples of the loam soil were preincubated for ranging from 0 to 50 days in the presence of calcium carbonate prior to phosphate application, the extractable phosphate concentration increased with preincubation time, and more phosphate was extracted from the soil maintained at 50% field capacity during the incubation. However, the extractable phosphate concentration in the sandyloam soil did not change with preincubation time and was not affected by moisture status. It may be concluded that the extractability of added phosphate was influenced by not only liming time but physical properties of soil.

• Korean Journal of Soil Science and Fertilizer
• /
• v.36 no.4
• /
• pp.233-238
• /
• 2003

The effect of phosphate solubilizing microbes (PSM) on plant P uptake and growth in rock phosphate applied soil was tested under a greenhouse condition. Tobacco plants were grown in nonsterilized soil inoculated with Penicillium oxalicum CBPS-3F-Tsa with or without rock phosphate application as P fertilizer. Phosphorus concentration in tobacco plants was increased by the application of rock phosphate, while inoculation of soil with fungi further significantly increased P concentration in tobacco plants compared with the noninoculated treatments. Phosphorus uptake by tobacco plants was also increased by the application of rock phosphate and PSM inoculation, and the significant comparison has been made with single rock phosphate treatment. Growth of tobacco plant was also significantly increased in the treatments receiving rock phosphate, while the combined application of rock phosphate and PSM further increased plant growth. It was concluded that the positive effect of PSM inoculation on plant growth was closely related in plant P content and uptake. These results suggest that Penicillium oxalicum CBPS-3F-Tsa could solubilize insoluble soil phosphates and rock phosphate which can promote growth and P uptake of tobacco plants.

• Journal of the Korea Concrete Institute
• /
• v.19 no.3
• /
• pp.333-339
• /
• 2007

The purpose of this study was to enhance bond performance between recycled PET (polyethylene telephthalat) fiber and cement composites through hydrophilic treatment using maleic anhydride grafted polypropylene(mPP). The mPP with various concentration of 0%, 5%, 10%, 15% and 20% to determine effect on bond behavior of recycled PET fiber were applied as experimental variables. Dog bone shaped specimens according to JCI SF-8 was applied to evaluate the bond strength and pullout energy. The results showed increased bond strength and pullout energy as concentration of mPP. Concentration of 15% mPP showed the most effective results while 20% showed reduced performance results. Because 15% mPP ensures perfect coating while 20% makes thick coating area that resulted in crack propagation and consequent separation of PET fiber and coated area during pullout load occurred. Enhancement mechanism of bond performance of recycled PET fiber and cement composites with each concentration of mPP could be conformed through investigation of microstructure of fiber surface.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.6
• /
• pp.1037-1044
• /
• 2000

The objective of this study is the preparation of activated carbon for BAC(biological activated carbon). Prepared activated carbon was measured iodine adsorption(mg/g). methylene blue adsorption(mg/g), B.E.T($m^2/g$), PSD(Pore Size Distribution) and 'Picabiol' which in commercial activated carbon for BAC. Activation method for this study was a chemical activation used the phosphoric acid. In the method, two important factors affected activation characterized in preparation were temperature and impregnated phosphoric acid concentration. Activation temperature and impregnated phosphoric acid concentration were changed the $600{\sim}800^{\circ}C$ and 35~50wt% respectively. Activation time was fixed for 3 hour. Optimal activation temperature was $800^{\circ}C$ and impregnated phosphoric acid concentrations was about 50wt%. By the above condition specific surface area, iodine adsorption number and methylene blue adsorption number resulted $1643.3m^2/g$, 1093 mg/g, 445.6 mg/g, respectively.

• Applied Biological Chemistry
• /
• v.40 no.2
• /
• pp.134-138
• /
• 1997

The objective of this study was to examine the effect of phosphorus deficiency on nitrogen fixation and photosynthesis of nitrogen fixing soybean plant under $CO_2$ enrichment condition. The soybean plants(Glycine max [L.] Merr.) inoculated with Bradyrhizobium japonicum MN 110 were grown with P-stressed(0.05 mM-P) and control(1 mM-P) treatment under control$(400\;{\mu}l/L\;CO_2)$ and enrichment$(800\;{\mu}l/L\;CO_2)$ enviromental condition in the phytotron equipped with high density lamp$(1000\;{\mu}Em^{-2}S^{-1})$ and $28/22^{\circ}C$ temperature cycle for 35 days after transplanting(DAT). At 35 DAT, phosphorus deficiency decreased total dry mass by 64% in $CO_2$ enrichment condition, and 51% in control $CO_2$ condition. Total leaf area was reduced significantly by phosphorus deficiency in control and enriched $CO_2$ condition but specific leaf weight was increased by P deficiency. Phosphorus deficiency significantly reduced photosynthetic rate(carbon exchange rate) and internal $CO_2$ concentration in leaf in both $CO_2$ treatments, but the degree of stress was more severe under $CO_2$ enrichment condition than under control $CO_2$ environmental condition. In phosphorus sufficient plants, $CO_2$ enrichment increased nodule fresh weight and total nitrogenase activity(acetylene reduction) of nodule by 30% and 41% respectively, but specific nitrogenase activity of nodule and nodule fresh weight was not affected by $CO_2$ enrichment in phosphorus deficient plant at 35 DAT. Total nitrogen concentrations in stem, root and nodule tissue were significantly higher in phosphorus sufficient plant grown under $CO_2$ enrichment, but nitrogen concentration in leaf was reduced by 30% under $CO_2$ enrichment. These results indicate that increasing $CO_2$ concentration does not affect plant growth under phosphorus deficient condition and phosphorus stress might inhibit carbohydrate utilization in whole plant and that $CO_2$ enrichment could not increase nodule formation and functioning under phosphorus deficient conditions and phosphorus has more important roles in nodule growth and functioning under $CO_2$ enrichment environments than under ambient condition.

• Biomedical Science Letters
• /
• v.2 no.2
• /
• pp.175-185
• /
• 1996

The mitogen-activated protein(MAP) kinase signal transduction pathway represents an important mechanism by which mitogen, such as serum and PMA, regulate cell proliferation and differentiation. Target substrates of the MAP kinase are located within several compartments containing plasma membranes and nucleus. We now report that serum addition induces proliferation of the P388 murine leukemia cell, but PMA does not, while both serum and PMA treatment cause translocation of the MAP kinase, mainly p42$^{mapk}$ isoform, from cytosol into the nucleus, which was monitored by immunoblot analysis using polyclonal anti-ERK1 antibodies. We investigated whether the MAP kinase was capable of phosphorylating c-Jun protein and GST-fusion proteins, the P562$^{kk}$N-terminal peptides (1-77 or 1-123 domain) of the T cell tyrosine kinase, using the partially purified MAP kinase by SP-sephadex C-50, phenyl superose and Mono Q column chromatography. We found that the partially purified MAP kinase was able to phosphorylate c-Jun protein and the GST-fusion protein expressed using E.coli DH5$\alpha$ which is transformed with pGEX-3Xb plasmid vector carrying of p562$^{kk}$N-terminal peptide-encoding DNA. These results imply that tyrosine kinase receptor/Ras/Raf/MAP kinase pathway is a major mechanism for mitogen-induced cell proliferation in P388 murine leukemia cell and that the various MAP kinase isoforms may have their own target substrates located in distinct subcellular compartments.

• Applied Biological Chemistry
• /
• v.35 no.3
• /
• pp.152-156
• /
• 1992

A study was condoled to investigate the effects of phosphate salts $(Na_2HPO_4\;and\;K_2HPO_4)$ on the emulsion stability of soy protein isolate (SPI) in terms of the salts concentration and addition order. When phosphates were added before emulsification, emulsion stability (ES) of SPI was improved at the concentration of 10 mM, while ES was decreased by addition of phosphates after emulsification. At high phosphate concentrations, ES of SPI was decreased by the addition of phosphates, regardless of the addition order. ES of SPI at the isoelectric point (pH 4.5) or in the presence of $CaCl_2$ was greatly enhanced by the phosphates. In both cases, the overall ES profile was found to be nearly similar to the solubility profile of SPI, indicating the positive relationship between solutibility and emulsion stability of SPI.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.2
• /
• pp.196-202
• /
• 2018

In this study, we investigated phosphate removal efficiency according to pretreatment (pyrolysis temperature, pyrolysis time, particle size) of oyster shells as a basic study for their recycling. And XAFS analysis and isothermal adsorption experiments were performed to investigate the phosphate removal characteristics of oyster shells. As a result, the removal efficiency was good at $600^{\circ}C$ pyrolysis temperature with 6 hour pyrolysis time and 0.355 ~ 0.075 mm particle size. Isothermal adsorption experiments showed that the Langmuir model is suitable for adsorption of oyster shells. XAFS analysis showed that calcium phosphate formed on the oyster shell pyrolyzed at $600^{\circ}C$. In other words, it was confirmed that the formation of calcium phosphate by the calcium ion elution of the oyster shell contributes to the decrease of phosphate concentration.

• Korean Journal of Food Science and Technology
• /
• v.39 no.5
• /
• pp.558-563
• /
• 2007

This study was conducted to analyze the cytotoxic effects of butylated hydroxytoluene (BHT) and propyl gallate (PG) in WB-F344 rat liver epithelial cells. Here we measured the inhibition level of gap junctional intercellular communication (GJIC) and elucidated the relationships between GJIC and mitogen-activated protein kinases (MAPKs) such as ERK, JNK, and p38. The cytotoxicities of BHT and PG appeared at concentrations of 1.0mM and 0.25mM, respectively, in the WB-F344 cells; and GJIC inhibition, which was analyzed by a scrape-loading/dye transfer assay and Western blotting analysis, appeared at 0.6mM for BHT and 0.1mM for PG, respectively. Also, the phosphorylations of Cx43, ERK, JNK, and p38 increased in dose-dependent manners. This suggests that BHT and PG treatments inhibited GJIC by the phosphorylation of MAPKs prior to cell damage.