• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제10권S_2호
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• pp.79-88
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• 2001

Humic acids react with chlorine to produce Trihalomethanes(THMs), known as carcinogens, during disinfection, the last stage in water purification. Currently, the removal of organic humic acids is considered the best approach to solve the problem of THM formation. Accordingly, the current study examined the adsorption of organic compounds of humic acids onto an inorganic carrier prepared from oyster shell waste. The adsorbent used was activated oyster shell powder(HAP) and silver ion-exchanged oyster shell powder(HAP-Ag), with CaCO$_3$ as the control. The adsorbates were phthalic acid, chelidamic acid, catechol, dodecylpyridinium chloride(DP), and 2-ethyl phenol(2-EP). The adsorption experiments were carried out in a batch shaker at $25^{\circ}C$ for 15 hours. The equilibrium concentration of the adsorbate solution was analyzed using a UV spectrophotometer and the data fitted to the Langmuir isotherm model. Since the solution pH values were found to be greater than the pKa values of the organic compounds used as adsorbates, the compounds apparently existed in ionic form. The adsorptive affinities of the organic acid and phenolic compounds varied depending on the interaction of electrostatic forces, ion exchange, and chelation. More carboxylic acids and catechol, rather than DP and 2-EP, were adsorbed onto HAP and HAP-Ag. HAP and HAP-Ag exhibited a greater adsorptive affinity for the organic compounds than CaCO$_3$, used as the control.

• 한국식품과학회지
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• 제29권5호
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• pp.1071-1074
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• 1997

무의 염절임 중 $Ca^{++}$, $K^+$ 및 $Mg^{++}$이 절임에 미치는 영향을 살펴보았다. 0.2M까지의 범위에서 $Ca^{++}$과 $K^+$의 첨가는 무의 절임 효과를 증가시켰고, $Mg^{++}$은 절임에 별로 영향을 미치지 못한 것으로 나타났다. $Ca^{++}$, $K^+$ 이온은 모두 0.2M까지 무의 염도 증가에 영향을 보였다. $Ca^{++}$과 $K^+$을 함께 첨가하였을 때 저농도에서는($0{\sim}0.01\;M$) 농도를 증가시킬수록 염도가 증가하였으나 0.2M의 농도에서는 일정하였다. $Mg^{++}$과 $Ca^{++}$을, $Mg^{++}$과 $K^+$을 함께 첨가하였을 때는 각각 $Ca^{++}$과 $K^+$이 무의 염도에 영향을 주는 것으로 나타났으며 $Mg^{++}$ 이온은 영향을 미치지 않았다.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.2900-2904
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• 2013

We present the synthesis and characterization of DTPA-bis(histidylamide) (1a), DTPA-bis(aspartamide) (1b), and their gadolinium complexes of the type $[Gd(L)(H_2O)]$ (2a:L = 1a; 2b:L = 1b). Thermodynamic stabilities and $R_1$ relaxivities of 2a-b compare well with Omniscan$^{(R)}$, a well-known commercial, extracellular (ECF) MRI CA which adopts the DTPA-bis(amide) framework for the chelate: $R_1$ = 5.5 and 5.1 $mM^{-1}$ for 2a and 2b, respectively. Addition of the Cu(II) ion to a solution containing 2b triggers relaxivity enhancement to raise $R_1$ as high as 15.3 $mM^{-1}$, which corresponds to a 300% enhancement. Such an increase levels off at the concentration beyond two equiv. of Cu(II), suggesting the formation of a trimetallic ($Gd/Cu_2$) complex in situ. Such a relaxivity increase is almost negligible with Zn(II) and other endogenous ions such as Na(I), K(I), Mg(II), and Ca(II). In vivo MR images and the signal-to-noise ratio (SNR) obtained with an aqueous mixture of 2b and Cu(II) ion in an 1:2 ratio demonstrate the potentiality of 2 as a copper responsive MRI CA.

• The Korean Journal of Physiology and Pharmacology
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• 제17권3호
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• pp.181-187
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• 2013

Reactive oxygen species (ROS) are generated in various cells, including vascular smooth muscle and endothelial cells, and regulate ion channel functions. $K_{Ca}3.1$ plays an important role in endothelial functions. However, the effects of superoxide and hydrogen peroxide radicals on the expression of this ion channel in the endothelium remain unclear. In this study, we examined the effects of ROS donors on $K_{Ca}3.1$ expression and the $K^+$ current in primary cultured human umbilical vein endothelial cells (HUVECs). The hydrogen peroxide donor, tert-butyl hydroperoxide (TBHP), upregulated $K_{Ca}3.1$ expression, while the superoxide donors, xanthine/xanthine oxidase mixture (X/XO) and lysophosphatidylcholine (LPC), downregulated its expression, in a concentration-dependent manner. These ROS donor effects were prevented by antioxidants or superoxide dismustase. Phosphorylated extracellular signal-regulated kinase (pERK) was upregulated by TBHP and downregulated by X/XO. In addition, repressor element-1-silencing transcription factor (REST) was downregulated by TBHP, and upregulated by X/XO. Furthermore, $K_{Ca}3.1$ current, which was activated by clamping cells with 1 ${\mu}M$ $Ca^{2+}$ and applying the $K_{Ca}3.1$ activator 1-ethyl-2-benzimidazolinone, was further augmented by TBHP, and inhibited by X/XO. These effects were prevented by antioxidants. The results suggest that hydrogen peroxide increases $K_{Ca}3.1$ expression by upregulating pERK and downregulating REST, and augments the $K^+$ current. On the other hand, superoxide reduces $K_{Ca}3.1$ expression by downregulating pERK and upregulating REST, and inhibits the $K^+$ current. ROS thereby play a key role in both physiological and pathological processes in endothelial cells by regulating $K_{Ca}3.1$ and endothelial function.

• 한국환경과학회지
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• 제31권12호
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• pp.1069-1078
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• 2022

This study investigated the weather conditions, fine particle concentration, and ion components in PM_2.5 when two cold fronts passed through Busan in succession on February 1 and 2, 2021. A analysis of the surface weather chart, AWS, and backward trajectory revealed that the first cold front passed through the Busan at 0900 LST on February 1, 2021, with the second cold front arriving at 0100 LST on February 2, 2021. According to the PM₁₀ concentration of the KMA, the timing of the cold front passage had a close relationship with the occurrence of the highest concentration of fine particles. The transport time of the cold front from Baengnyeongdo to Mt. Gudeok was approximately 11 hours . The PM₁₀ and PM_2.5 concentrations in Busan started to increase after the first cold front had passed, and the maximum concentration occurred two hours after the second cold front passed. The SO₄^2-, NO₃^-, and NH₄⁺ concentration in PM_2.5 started to increase from 1100 to 1200 LST on February 1, after the first cold front passed, and peaked at 0100 LST to 0300 LST on February 2. However, the highest Ca²⁺ concentration was recorded 2-3 hours after the second cold front had passed.

• 자원환경지질
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• 제34권5호
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• pp.447-460
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• 2001

부산지역의 지열수는 Na-Cl형으로서 한국의 타지역에서 산출되는 지열수에 비해 전기전도도(921~6,520 ${\mu}$S/cm)와 총용존고체함량(608~3,390 mg/L)이 비교적 높다. 부산지역 지열수는 Mg를 제외한 주요 이온들이 온도가 증가함에 따라 농도가 대체로 증가하는 약한 정의 상관관계를 나타낸다. 주요 양이온의 함량은 Na>Ca>K>Mg의 순으로 나타나며, 해수에 비해 Ca가 부화되어 있고, Mg가 결핍되어 있다. 이 지열수의 Br 함량은 모두 해수보다 낮으며, 온도가 증가함에 따라 증가하는 정의 상관관계를 보인다. 이를 종합하면, 부산지역 지열수는 심부로 순환하는 해수가 주변 모암과의 상호반응에 의해 해수에 비해 상대적으로 증가된 Ca와 Sr의 함량과 상대적으로 결핍된 Mg, Na와 K의 함량을 갖는 지열수를 형성한 것으로 여겨진다. 또한 주요 이온들과 온도와의 상관관계로 볼 때, 높은 염도의 지열수가 상승하는 동안 저온의 주변 지하수와 혼합되어 냉각과 함께 희석작용이 있었던 것으로 보인다. 이 지열수의 기원과 진화를 정확히 규명하기 위해서는 안정동위원소 연구와 함께 전체 지구화학계에 대한 물-암석 반응 모델링이 수행되어야 할 것이다.

• Journal of Plant Biology
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• 제31권2호
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• pp.91-100
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• 1988

The effect of Ca2+ and polyamines on the activity $\beta$-glucan synthetase II(GSII) related to cell wall synthesis was studied in carrot suspension cultured cells. The activity of GS II is four times higher than that of $\beta$-glucan synthetase I in carrot suspension cultured cells and in vitro expreiment, the activity of GSII was increased in response to increase in concentration of Ca2+ and polyamines. When carrot suspension cultured cells were incubated together with Ca2+ and polyamines, the GSII activity was high at 0.1mM of Ca2+ and 1mM of putrescine. Also, polycationic poly-L-lysine and poly-L-ornithine increased about 50% the GSII activity than that of the control, respectively. These results may imply that Ca2+ and polyamines were related to the enzyme activity as a polycationic nature. In addition, verapamil as the calcium channel blocker and flunarizine as an antagonist of calcium mechanism in cytoplasm decreased GSII activity ramarkably, Ca2+ and calmodulin stimulated GSII activity as Ca2+ of free ion rather than Ca2+ calmodulin complex. The effect of 2,4-D on the GSII activity in culture medium is shown to be low at 0.1mg per liter and GSII activity increased about 30% more than that of the 0.1mg/l at the range of 0.3-1.0mg per litere. Cummulative results suggest that Ca2+ and polyfamines stimulate the cell wall synthesis by means of the enhancement of GSII activity responsible for synthesizing the cell wall components.

• 대한지역사회영양학회지
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• 제8권3호
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• pp.349-355
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• 2003

We developed a dietary supplement using natural herbs and nutrients for the growth and exercise performance improvement. It called 50-22 supplement containing distilled extracts of natural herbs to remove bitterness and the addition of Vitamin B1, B6, Ca and xylitol. We investigated on the effect of 10-22 supplementation on the maximal exercise performance, IGF-1 (insulin like growth factor-1) concentration and antioxidant activity in SD rat model. In result, JR-22 supplement group was better than control group about 10％ in exercise performance test and increased about 63％ of IGF-1 concentration in blood. In addition, the oxidative damage induced by exercise was reduced by JR-22 supplementation. Therefore, we suggested that 50-22 supplementation enhanced effectively exercise performance and IGF-1 concentration and reduced to oxidative stress in muscles. Also, we analysed biochemical factors in blood for the safety of JR-22 supplement. We known that there is no change of blood lactic acid, ammonia, inorganic phosphorous ion and creatine kinase activity. (Korean J Community Nutrition 8(3) : 349∼355, 2003)

• 환경위생공학
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• 제8권2호
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• pp.155-168
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• 1993

The chemical components of rain water and aerosol in Bulkwang of Seoul and Yang-Paying of Kyunggi-do were compared in order to investigate that pollutants at urban area influences rain water and aerosol component. The following is the result of this study. 1) The pH of rain water was shown 4.82 at urban area and 5.69 at suburban area. 2) The mean concentration of $SO_4^{2-}$ within rain water at suburban was nearly the same at urban area but the mean concentration of $Na^{+},Ca^{2+},Mg^{2+}$ and $NH_4^{2+}$ at suburban area was higher than the corresponding levels at urban area. 3) The ion component of aerosol at suburban was shown 68% of that at urban area. This study proved that the concentration of rain water and aerosol component was under the influence of movement of air current.

• Journal of Microbiology and Biotechnology
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• 제12권4호
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• pp.683-686
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• 2002

To achieve optimum operation of a thermophilic aerobic digestion (TAD) process for waste activated sludge (WAS), TAD experiments using Bacillus stearothermophilus (ATCC 31197) were carried out to investigate the optimum concentration of dissolved oxygen (DO). TAD reactors were operated at DO concentrations of 0, 1, 2, 3, 4, and 5 ppm, and the results showed that the WAS could be successfully degraded by a TAD system operated with a DO concentration of 1 ppm and above. When the TAD system with an optimum additive (2 mM Ca ion), selected from a previous study, and 1 ppm DO concentration were combined with a thermal pretreatment ($121^{\circ}C$, 10 min), the results exhibited upgraded total suspended solids and an enhanced protein degradation.