• Horticultural Science & Technology
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• v.33 no.6
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• pp.854-859
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• 2015

This experiment was performed to develop a model for nutrition ion concentration and EC in regard to change in pH from 4.0 to 8.0 in nutrient solution. The pH changes according to the variation of $HPO_4{^{-2}}$ and $H_2PO_4{^-}$ in the nutrient solution while variation of EC increased from pH 4.0 to 5.0, stabilized from pH 5.0 to 7.0 and increased again from pH 7.0 to 8.0. For the variance of major elements in the nutrient solution, K, Ca, N and P increased while pH was higher, especially the variables for K and P were increased largely. On the other hand, variables of Mg and S were stable. Based on analysis of the ion balance model of nutrient solution, the cation increased than anion over rising the variation of pH while balance point of ion moved from a-side to d-side. In addition, the imbalance increased while it moved away from the EC centerline as variance of pH increased. It was larger than effect of EC variance to correction values of equivalence ratios of K and Ca about variation of $HPO_4{^{-2}}$ and $H_2PO_4{^-}$ while as variance of pH increased, K decreased but Ca increased. These showed the result that variance of pH about correction values of equivalence ratios of K and Ca gave a second-degree polynomial model rating of 0.97. Through this research, it was identified the pH variable model about variance among pH, ion and EC according to gradient of phosphate.

• Development and Reproduction
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• v.24 no.4
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• pp.297-306
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• 2020

Repetitive changes in the intracellular calcium concentration ([Ca²⁺]i) triggers egg activation, including cortical granule exocytosis, resumption of second meiosis, block to polyspermy, and initiating embryonic development. [Ca²⁺]i oscillations that continue for several hours, are required for the early events of egg activation and possibly connected to further development to the blastocyst stage. The sources of Ca²⁺ ion elevation during [Ca²⁺]i oscillations are Ca²⁺ release from endoplasmic reticulum through inositol 1,4,5 tri-phosphate receptor and Ca²⁺ ion influx through Ca²⁺ channel on the plasma membrane. Ca²⁺ channels have been characterized into voltage-dependent Ca²⁺ channels (VDCCs), ligand-gated Ca²⁺ channel, and leak-channel. VDCCs expressed on muscle cell or neuron is specified into L, T, N, P, Q, and R type VDCs by their activation threshold or their sensitivity to peptide toxins isolated from cone snails and spiders. The present study was aimed to investigate the localization pattern of N and P/Q type voltage-dependent calcium channels in mouse eggs and the role in fertilization. [Ca²⁺]i oscillation was observed in a Ca²⁺ contained medium with sperm factor or adenophostin A injection but disappeared in Ca²⁺ free medium. Ca²⁺ influx was decreased by Lat A. N-VDCC specific inhibitor, ω-Conotoxin CVIIA induced abnormal [Ca²⁺]i oscillation profiles in SrCl₂ treatment. N or P/Q type VDC were distributed on the plasma membrane in cortical cluster form, not in the cytoplasm. Ca²⁺ influx is essential for [Ca²⁺]i oscillation during mammalian fertilization. This Ca²⁺ influx might be controlled through the N or P/Q type VDCCs. Abnormal VDCCs expression of eggs could be tested in fertilization failure or low fertilization eggs in subfertility women.

• Korean Journal of Ecology and Environment
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• v.35 no.3 s.99
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• pp.213-219
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• 2002

The CellCaSi, a porous silicate material, was tested for the removal of phosphorus (P as phosphate) in water. The effect of the CellCaSi was investigated on the basis of both particle size (under 1,2, and 4 mm) and added amount (0, 1, 2.5, 5, and 10 g/1) of the CellCaSi. The removal efficiency of phosphorus was highest with a particle size of under 1 mm and also increased with an increasing amount of the CellCaSi. The pH change showed little effect on the phosphorus removal of the CellCaSi. The calcium ion was eluted from the CellCaSi into the water, while the aluminium and iron were not. The eluted calcium ion was combined with dissolved phosphorus and then precipitated. The highest removal efficiency of phosphorus was obtained by the combined addition of the CellCaSi, calcium chloride, and ferric chloride. That is, the phosphorus concentrations of 0.10 and 1.0 mg/1 decreased to 0.03 and 0.47 mg/l by the addition of the CellCaSi (1 g/l), calcium ion (30 mg/l), and ferric ion (1 mg/l) at day 8 after treatment. The water qualities at the end of the experiment were as follows: pH was 8.1 and conductivity was 318 ${\mu}$S/cm (a registered maximum conductivity of 500${\mu}$S/cm for raw and potable wafers).

• Microbiology and Biotechnology Letters
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• v.19 no.6
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• pp.619-623
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• 1991

To investigate nisin production and resistance of Lactococcus lactis ssp. tactis ML (L. lactis $ML_8$, effects of medium, pH of culture broth, and cell growth on the nisin activity, and effect of nisin with or without $Ca^[2+}$ ion on the growth of L. lactzs were analyzed. In the bio-assay of nisin by the agar diffusion method, inhibition-zone diameter of Micrococcus Javus was propotional to the logarithm of nisin concentration ranged 0.5~20 unitlml (12.5~500 ng/mf). Nisin activity of the pasteurized culture filtrates of L. lactis MLs was high at pH 2!3 but was inactivated completely at pH over 6.0. Nisin production of the L. lactis $ML_8$ cultured on LTB broth increased at late logarithmic phase and reached 10.5 unitlml after 16 hr. The cell growth of L. lactis LM 0230, a plasmid free and nisin sensitive strain, was inhibited on agar medium containing 7 unitlrnl of nisin, while L. lactis $ML_8$ showed high survival ability at 20 unitld of nisin. When 40 mM $Ca^[2+}$ ion was added to Elliker broth with 8 unitlml of nisin, the growth pattern of L. lactis $ML_8$ was similiar to that on control medium which did not contain nisin and $Ca^[2+}$ ion, and this suggested that $Ca^[2+}$ increased the nisin resistance of the L. lactis.

• Korean Journal of Veterinary Research
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• v.38 no.2
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• pp.280-289
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• 1998

Voltage-sensitive ion channels contribute to establishment of the cell excitablity and the generation of the cellular function. At hamster oocytes in the primitive stage during developing process, an inward current elicited by voltage pulses was found to be carried mainly by $Ca^{2+}$. Even at present, $Ca^{2+}$ channels serve as the most probable route to pass this inward current but there is no evidence of the presence of this channels in eggs. To date, both the characteristic properties and the physiological role in the early stage of development remain unclear. Here we examined the characteristic properties of the inward current and changes in this currents at unfertilized oocytes, fertilized zygotes and two-cell embryos using whole-cell voltage clamp technique. The inward current carried reportedly by $Ca^{2+}$ was remained following removing external $Ca^{2+}$ but completely abolished by further replacement of impermeants such as tetramethylammonium ion ($TMA^+$) or $choline^+$ instead of $[Na^+]_0$. Tetrodotoxin did not affect on this inward current remained at $[Ca^{2+}]_0$-free condition. Removal of $Na^+$ ion out of the experimental solution clearly decreased the current. After adding 2mM $Ca^{2+}$ to the $Na^+$-free media, the inward current was restored. Interestingly, this current carried by either $Ca^{2+}$ or $Na^+$ was decreased by the reduction of intracellular $Cl^-$ concentration, or by $Cl^-$ channel blockers such as niflumic acid, DIDS and SITS. When $Cl^-$ concentration was lowered without changes in other ionic components, this inward current was reduced. At fertilized oocytes and two-cell embryos, the inward current carried by $Ca^{2+}$ and $Na^+$ was severely reduced. Also $Cl^-$ component could not be observed. From these results, the inward current is composed of $Ca^{2+}$, $Na^+$ and $Cl^-$ component, suggesting that the channel carrying this inward current is not selective specifically to $Ca^{2+}$. During early stage of development, the voltage-sensitive ion current seems not to contribute essentially to the cell cleavage and differentiation. The loss of $Cl^-$ component after fertilization suggests that $Cl^-$ may play a role in maintaining the viability of unfertilized ova.

• Analytical Science and Technology
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• v.8 no.3
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• pp.221-227
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• 1995

The fiber optic fluorosensor that shows a specific selectivity for calcium ion is studied. This sensor employs protein Calmodulin(CaM) which forms a fluorescent chelate with $Ca^{2+}$. A dialysis membrane is used to entrap a fluorescein isothiocyanate-labeled CaM solution at the common end of a bifurcated fiber optic bundle. The sensing mechanism of this sensor is based on the shifts in the fluorescence spectrum of metal-calmodulin complexes which FCaM forms a chelate with $Ca^{2+}$. Upon binding with $Ca^{2+}$, CaM undergoes a conformational change which induces a change in the fluorescence of FCaM. This change in fluorescence signal which is measured by photomultiflier tube is related to the concentration of $Ca^{2+}$ for calibration curve. Detection limit for $Ca^{2+}$ and the interference effects by $Mg^{2+}$, $Eu^{3+}$ and $La^{3+}$ for this sensor are studied. Response time and life time for this fluorosensor are also investigated.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.221-222
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• 2009

The results showed that the addition of VAE polymer strongly reduces the $Ca(OH)_2$ formation, being this result attributed to reduce degree of cement hydration caused by different ion elution amount of polymer modified cement pastes and interaction between acetate anion from the partial hydrolysis of co-polymer and Ca$^{2+}$ion from OPC hydration.

• Journal of Industrial Technology
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• v.33 no.A
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• pp.89-92
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• 2013

The characteristics of floc formation of the iron(Fe) ions was studied for developing the process treating the acid mine drainage. The metal ions in aqueous solution oxidized with oxygen in air, which generated hydrogen ion and lowered the pH of the aqueous solution. The iron(Fe) ions were formed into flocs by the acid-base reaction with the added $Ca(OH)_2$ for the neutralizing the solution. There were several variables affecting the formation, size and color of floc; whether air was present or not, air feeding rate, oxidizing time, concentration of $Ca(OH)_2$, the acid-base reaction time of the $iron(Fe)-Ca(OH)_2$. For proper formation of the $iron(Fe)-Ca(OH)_2$ flocs and developing the floc treating system, the control variables mentioned above should be considered.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.793-799
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• 2011

We report the complexation behavior of calix[4]arenemonoquinone-triacid (CTAQ), which is an electroactive and water-soluble receptor for calcium ion. UV-visible and NMR spectroscopic studies revealed that CTAQ in aqueous media forms 1:2 as well as 1:1 (metal ion:CTAQ) stoichiometric complexes with $Ca^{2+}$, $Sr^{2+}$, and $Ba^{2+}$ ions. The nonlinear fitting of titration curves based on UV-visible absorption spectra showed that the binding constants of CTAQ for $Ca^{2+}$ ion are 4 $({\pm}2){\times}10^6\;M^{-1}$ for 1:1 and 1.4 $({\pm}0.5){\times}10^{11}\;M^{-2}$ for 1:2 complex. NMR conformational studies and the titration curves corroborate that the $Ca^{2+}$:CTAQ complex in aqueous solution is not present in the form of merely 1:1 one, being consistent with UV-visible spectrophotometric results. The Monte Carlo simulation supports the presence of a stable conformer of 1:2 complexes in which a $Ca^{2+}$ ion is interposed between two CTAQs at the global minimum. This is the first model of 1:2 stoichiometric complex of calix[4]arene and alkaline earth ions in aqueous media.

• Membrane Journal
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• v.26 no.2
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• pp.152-158
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• 2016

The Chlor-alkali (CA) membrane cell is a major electrolysis system to produce valued chemicals such as chlorine gas and sodium hydroxide. The CA membrane process has been attracted in the industries, since it has relatively low energy consumption when compared with other CA processes. The key component in CA process is perfluorinated sulfonic acid ionomer membranes, which provide ion-selectivity and barrier properties to produced gases. Unfortunately, there is limited information to determine which factors should be satisfied for CA applications. In this study, the influences of PFSA membranes on CA performances are disclosed. They include ion transport behaviors, gas evolution capability, and chemical/electrochemical resistances under CA operation conditions.