• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2301-2307
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• 2015

The aim of this study was to evaluate the feasibility of application of the high voltage impulse (HVI) technique to the control of scale formation by calcium carbonate, which is pointed out as an important issue in industrial water treatment. The HVI system consisted of the power supply, high voltage generator, capacitors, switch and impulse generator was designed and made in laboratory scale, which can make 17kV impulse. HVI was introduced to the reactor that was filled with synthetic water containing $Ca^{2+}$ion. The concentration of calcium ion decreased only 3.0% after 5 minutes of contact time. However, it decreased up to 13.7% after 60 minutes of HVI contact time. Temperature and pH increased but conductivity decreased due to precipitation of the calcium carbonate. Although the decrease in concentration of calcium ion was not sufficient, it was verified that the HVI technique could be applicable for the softening and desalting processes.

• Resources Recycling
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• v.12 no.4
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• pp.38-43
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• 2003

Phosphate is an essential material for the growth of organisms. However. since relatively small amount is required. a large amount of phosphate is abandoned in wastes and wastewater. which contaminate the ecological environment including aquatic system. Purpose of this study is to treat especially high concentrated phosphate wastewater by use of calcium precipitation method. The pH range considered was from 6 to 12 and the maximum removal of phosphate was attained at pH 12. The con-centration of phosphate was observed to decrease rapidly until a half amount of calcium ion to its equivalent for the formation of calcium phosphate precipitate was added. which resulted in the decrease of the remaining concentration of phosphate down to 0.0027 mM. The effect of fluoride ion was examined and the concentration ratio between the phosphate and fluoride ion did not have any significant influence on the removal efficiency of phosphate. The effect of pH was also investigated. With the increasing of the pH in solution, the removal rate of phosphate was increased. Also it was investigated that the effect of fluoride on the phosphate removal was not significant.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.3
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• pp.389-399
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• 2019

The calcium carbonate saturation state in the Ulleung Basin of East Sea was calculated using bottle data set of pH, dissolved inorganic carbon and total alkalinity obtained from the year 1999, 2014, 2017, and 2018 cruise. In the 2010s calcium carbonate saturation state was significantly lowered at all depth compared to the 1999 reference state. Accordingly calcite saturation horizon and aragonite saturation horizon shoaled to 500 m and 200 m, respectively. A key chemical species for the calcium carbonate saturation state, carbonate ion showed distinctive profile between upper and deep waters: it is moderately high (${\sim}175{\mu}mol\;kg^{-1}$) in upper waters and very low (< ${\sim}50{\mu}mol\;kg^{-1}$) in the deep waters. However the decreasing trend of carbonate ion concentration was pronounced in the upper water than deep waters, suggesting atmospheric $CO_2$ penetration is largely confined to the upper waters in the 2000s.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.1
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• pp.87-94
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• 2021

Skin photoaging occurs due to chronic exposure to solar ultraviolet radiation (UV), the main factor contributing to extrinsic skin aging. Clinical signs of photoaging include the formation of deep, coarse skin wrinkles and hyperpigmentation. Although melanogenesis and skin wrinkling occur in different skin cells and have different underlying mechanisms, their initiation involves intracellular calcium signaling via calcium ion channels. The ORAI1 channel initiates melanogenesis in melanocytes, and the TRPV1 channel initiates MMP-1 production in keratinocytes in response to UV stimulation. We aimed to develop a drug that may simultaneously inhibit ORAI1 and TRPV1 activity to help prevent photoaging. We synthesized nootkatol, a chemical derivative of valencene. TRPV1 and ORAI1 activities were measured using the whole-cell patch-clamp technique. Intracellular calcium concentration [Ca2+]i was measured using calcium-sensitive fluorescent dye (Fura-2 AM). UV-induced melanin formation and MMP-1 production were quantified in B16F10 melanoma cells and HaCaT cells, respectively. Our results indicate that nootkatol (90 μM) reduced TRPV1 current by 94% ± 2% at -60 mV and ORAI1 current by 97% ± 1% at -120 mV. Intracellular calcium signaling was significantly inhibited by nootkatol in response to ORAI1 activation in human primary melanocytes (51.6% ± 0.98% at 100 μM). Additionally, UV-induced melanin synthesis was reduced by 76.38% ± 5.90% in B16F10 melanoma cells, and UV-induced MMP-1 production was reduced by 59.33% ± 1.49% in HaCaT cells. In conclusion, nootkatol inhibits both TRPV1 and ORAI1 to prevent photoaging, and targeting ion channels may be a promising strategy for preventing photoaging.

• Preventive Nutrition and Food Science
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• v.12 no.4
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• pp.217-221
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• 2007

Within the elderly population, the use of calcium supplements and the intake of calcium from food are on the rise in order to maintain health. Calcium is absorbed as an ion in vivo, leading to speculation that absorption efficiency is affected by the solubility of the calcium consumed. In our study, the bioavailability of two types of calcium supplements with different solubilities was evaluated. Experimental animals were fed water-soluble or insoluble calcium supplements for 6 weeks. We found that blood alkali phosphatase activity, osteocalcin content, and urine crosslinks values were not different between the groups. Similarly, the degree of apparent calcium absorption between the two calcium supplements was not significantly different. The bone mineral density and bone mineral content of the femur and the tibia increased in the group that consumed insoluble calcium compared with those of the water-soluble calcium supplemented group. However, when considering body weight, the bone mineral density value for all areas, including the spine, was significantly higher in the group that consumed the water-soluble calcium supplement.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.197-203
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• 2013

The diagnostic assay of calcium ion was sought using a modified sensor with square-wave stripping voltammetry (SWSV) and cyclic voltammetry (CV). In this study, simple graphite pencil was used as working, reference, and auxiliary electrodes. By coating the working electrodes with DNA, their sensitivity was very much improved, and good results were yielded. Moreover, clean seawater was used as an electrolyte solution instead of acid and base electrolytes to lessen the expenses involved in the experiment. The analytical optimum conditions were also examined. These conditions were attained at the low detection limit of $0.6ugL^1$. After that, the results were applied to drinking water of milk contain.

• Journal of the Korea Institute of Building Construction
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• v.19 no.1
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• pp.31-38
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• 2019

In this study, amine derivatives and ion exchange resins were selected to actively control penetration ions ($SO{_4}^{2-}$, $Cl^-$) as the element technology of repair materials for concrete structures in drainage environments. Ions ($SO{_4}^{2-}$, $Cl^-$) adsorption performance and corrosion resistance of calcium hydroxide solution with amine derivative and ion exchange resin were confirmed by ion chromatography and potentiostat analysis. As a result of the experiment, it was confirmed that the amine derivative is excellent in the adsorption of chlorine ion and the ion exchange resin is excellent in the adsorption of sulfate ion. It has been confirmed that corrosion resistance can be increased by proper combination of two materials in the calcium hydroxide solution containing sulfate ion and chloride ion simulating sewage environment.

• Journal of Korean Society on Water Environment
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• v.23 no.3
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• pp.371-376
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• 2007

The features of precipitating reaction of fluorine have been examined under several aquatic conditions by employing calcium ion as a precipitant. Based on MINTEQ program, fluorine was found to exist in the forms of $H_2F_2$ and HF in strong acidic environment and change into $F^-$ with increasing pH. In the experimental condition, the precipitating reaction of fluorine progressed rapidly within a few minutes after the reaction started and reached its equilibrium in 10 minutes. As the addition of precipitant was increased, removal of fluorine by the formation of precipitate was promoted and its was also enhanced by the rise of pH. The precipitating reaction of fluorine was impeded when its initial concentration was low and X-ray analysis showed that the crystalline structure of precipitate was mainly $CaF_2$ with partly NaF. Coexisting phosphate in solution influenced the fluorine removal by impeding the precipitate formation and similar effect was found when metallic ion such as $Zn^{2+}$ was present with fluorine.

• The Korean Journal of Pharmacology
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• v.19 no.2
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• pp.9-16
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• 1983

The effect of higenamine upon the interval-strength relationship was kinetically analyzed, and compared them with epinephrine and calcium ion. The followings are result obtained : 1) Polyphasic patterns were seen by all agents applied on the interval-force curve of rabbit atrial muscle. 2) Higenamine, unlike calcium ion, increased the amount of PIEA produced per beat dose-dependently and scarcely affected the disappearance of NIEA. 3) Higenamine appeared to similar pattern with epinephrine in augmenting the PIEA, not affecting the NIEA. 4) Calcium ion slightly influenced the PIEA, rather hastened the disappearance of NIEA. From these result the positive inotropic action of higenamine was attributed solely to increment of PIEA.

• Journal of Chest Surgery
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• v.21 no.2
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• pp.240-245
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• 1988

This study was prospectively planned to realize the reduction of calcium ion in serum along with the cardiopulmonary bypass[CPB], to find out the cause of the reduction, and to verify the justification of the classical methods of calcium replacement. Nine patients with various open heart surgeries by CPB in 1987 wee selected at random. Calcium chloride was added as follows:: For each unit of ACD blood transfusion, 600mg of calcium chloride was added. In case of massive transfusion, 600 mg of calcium chloride was injected every 2 or 3 units of transfusion. On occasions such as weaning from CPB, or following defibrillation, or hypotension, weak myocardial contractility of the heart, calcium chloride was needed in an amount of 10 mg / kg. In ICU, calcium chloride was limited to use in low serum level or in emergency use. Total calcium decreased early bypass and progressively increased above the preoperative value during late bypass and three hours thereafter, Ionized calcium increased during late bypass and three hours following. Total and ionized calcium depicted similar patterns of change during open heart surgery. Decrease of the calcium at the early bypass was thought from reduction of total protein and alkalosis during bypass. Meanwhile, increase of both calciums during the end of surgery was presumably attributable to addition of calcium chloride in priming solution, injections of calcium chloride in the process of termination of bypass. We conclude that enough calcium was replaced by the classical methods of calcium supplement.