• 상하수도학회지
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• 제32권3호
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• pp.235-242
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• 2018

Corrosion inhibitors including calcium hydroxide have been used to prevent corrosion in the pipes for tap water supply. The corrosion index (i.e., Langelier Index) differs by area and water quality. The corrosion indices of the areas studied differed by more than 2.0. The 'homogenized' calcium hydroxide was added to the treated water at the K water treatment plant, in order to increase the value of the corrosion index and the concentration of calcium. As the result, the concentration of calcium was increased while the turbidity and pH changed little. The corrosion rate of the tap water with the 'homogenized' calcium hydroxide could be slowed down pretty much. The results suggested that the technology of 'homogenization' of calcium hydroxide can applied to tap water and desalinated water to prevent corrosion in water pipes even in corrosive pipes.

• 한국어병학회지
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• 제9권1호
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• pp.41-51
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• 1996

경골어류의 혈관평활근에 대한 adrenaline성 조절기작을 규명의 일환으로 틸라피아의 배대동맥을 사용하여 Adrenergic agonist의 효과와 그 매개에 관여하는 수용체의 subtype에 대한 연구를 하였으며 그 결과는 다음과 같다. 1. Epinephrine, norepinephrine, phenylephrine, clonidine 및 methoxamine은 tilapia의 배대동맥에 대하여 농도의존적인 혈관수축효과만을 나타내었으며, 효력은 epinephrine, norepinephrine, phenylnephrine, clonidine, methoxamine의 순이었으며, 이들 수축반응은 혈관내피세포의 존재유무에 영향을 받지 않았다. 2. Epinephrine, norepinephrine, phenylephrine 및 clonidine 의 농도의존적인 혈관수축반응곡선은 선택적인 $\alpha_2$-adrenergic 수용체 길항제인 yohimbine의 농도가 증가함에 따라 오른쪽으로 평행이동 되었으며, epinephrine과 norepinephrine은 선택적인 $\alpha_1$-수용체 길항제인 prazosin의 농도가 증가함에 따라 오른쪽으로 평행이동되었다. 3. Epinephrine과 norepinephrine의 혈관수축반응은 calcium제거 생리적 완충용액에서는 각각 약 41%, 51% 소실되었며, calcium 유입차단제인 verapamil에 의해서도 거의 유사한 경향을 보였다. 이상의 실험결과들을 종합하면 Catecholamine류는 수축효과만을 나타내었으며 혈관내피세포 존재유무와는 무관하였다. 이러한 수축작용은 $\alpha_1$- 및 $\alpha_2$-adrenergic receptor가 모두 매개하였으며 voltage dependent $Ca^{2+}$ channel을 통하여 유입된 세포외액의 $Ca^{2+}$과 세포내 $Ca^{2+}$의해 일어난다고 사료된다.

• Journal of the Korean Wood Science and Technology
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• 제20권4호
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• pp.57-64
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• 1992

The unique cell wall micropores of pulp fiber can be utilized as loading site in variety of important practical application which could be the basis of new papermaking technologies. One of these includes the manufature of paper containing higher levels of in situ filler precipitated. Hardwood pulp fiber were first impregnated with the solution of sodium carbonate($Na_2CO_3$). The micropores in cell wall of pulp fibers were filled with the liquid salt solution. The second calcium nitrate($Ca(NO_3)_2$) solution formed an insoluble calcium carbonate($CaCO_3$) precipitate within the cell wall micropores by interacting with the first sodium carbonate solution. The effects of chemical concentration and dryness of pulp fibers on the retention of cell wall micropore loaded filler were investigated. The paper properties of cell wall micropore loaded pulp fibers were compared with those of conventionally loaded and lumen loaded pulp fibers. Also the presense of the fillers within the cell wall micropore was observed by SEM. Increasing the chemical concentration to generate the calcium carbonate increased the retention of filler in cell wall micropore loaded pulp fibers. The particle size distribution of precipitated calcium carbonate ranged from $0.1{\mu}m$ to $80{\mu}m$. But, the average particle size of cell wall micropore loaded calcium carbonate was $4{\mu}m$. The paper made from never dried pulp fibers, the cell wall micropores which were filled with calcium carbonate, had better mechanical and optical properties than those of conventionally loaded or lumen loaded pulp fibers.

• Journal of Ginseng Research
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• 제22권2호
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• pp.126-132
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• 1998

In the present study, we examined effects of ginseng saponins (ginsenosides) on pp60c-src protein tyrosine kinase (PTK) activity, intracellular calcium concentration ([$Ca^{2+}$]i), and cell proliferation in NIH3T3 cells. Eight different ginsenosides [ginsenoside-Rb1 (G-$Rb_1$), -$Rb_2$, -Rc, -Rd, -Re, -Rf, -$Rg_1$, -$Rg_2$) and ginseng total saponin (GTS) were used for these experiments. All ginsenosides and GTS tested stimulated the activation of $pp60^{c-src}$ kinase, and especially G-$Rb_1$,-Rd,-$Rg_1$, and -$Rg_1$ showed a higher stimulatory effect than others at 16.7 $\mu\textrm{g}$/ml of ginsenosides with a 18 hr-incubation, increasing the activity by 4.5, 3.5, 3.5, and 3.0-fold, respectively, over that of untreated control. In addition, both G-Rd and -$Rg_2$)Rg2 increased ($Ca^{2+}$), to 202 and 334 nM, respectively, about 2-3-fold above the basal level within 7min at 250 $\mu\textrm{g}$/yml of ginsenosides. The increases of ($Ca^{2+}$), were eliminated by Pretreatment of EGTA, an extracellular calcium chelator, suggtasting that they result from an influx of calcium ion from extracellular medium rather than an efflux from intracellular calcium store, endoplasmic reticulum (ER). All ginsenosides studied enhanced cell proliferation to 1.2-1.4-fold over that of untreated control at 5~250 $\mu\textrm{g}$/ml of concentrations. Interestingly the promotion of cell proliferation by ginsenosides corresponded with the activation of c-src kinase, which is an early step in the mitogenic signaling cascade. Taken together, we suggest that some ginsenosides may lead to cellProliferation via the activation of cellular signal transduction Pathway involving $pp60^{c-src}$ kinase.

• 대한화학회지
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• 제5권1호
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• pp.1-6
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• 1961

It is important to study hydrazine because of the development of new uses for its derivatives. The Rasching method is the only satisfactory one for synthesizing hydrazine; it involves the oxidation of ammonia by sodium hypochlorite in the presence of some such catalyst as gelatin. Calcium hypochlorite was substituted for the sodium hypochlorite particularly in this work, applying agar-agar as catalyst. The results of the experiments are as follow: 1. The yield is proportional to the mole-ratio of ammonia to available chlorine in calcium hypochlorite and about 60% is obtained when the ratio is 20. 2. Agar-agar can be used as a catalyst and its proper concentration in the solution is 0.005%. 3. Proper concentration of available chlorine in the reaction solution is 0.23 mole/l. 4. The most effective condition for the reaction is a temperature of $60{\sim}65^{\circ}C.$ maintained for $20{\sim}25min$. 5. The reaction takes place equally well in either an open or closed container. 6. When calcium hypochlorite is applied in place of sodium hypochlorite, the yield of hydrazine is increased as much as 17%. 7. The yield of hydrazine is decreased by eliminating the suspension of $Ca(OH)_2$ which results from the use of calcium hypochlorite. 8. When $Ca(OH)_2$ is added to Rasching process, the yield of hydrazine is raised normally. 9. The fact that some metal ions, such as $Cu^{++},$ inhibit the formation of hydrazine was proved. 10. The suspension of $Ca(OH)_2$ acted as a remarkable adsorbent for $Cu^{++}$ like gelatin. The suspension of $Ca(OH)_2$ which results from the use of calcium hypochlorite acts as a catalyst, absorbing metal ions, to increase the yield of hydrazine. So I think that calcium hypochlorite is a more efficient oxidant than sodium hypochlorite in hydrazine syntheses.

• Toxicological Research
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• 제14권4호
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• pp.507-513
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• 1998

The purpose of this study was to clarify the effect of silica on cytosolic free calcium mobilization and cell injury in primary cultured rat hepatocytes. Cytosolic free calcium concentration ([Ca$^{2+}$]) was measured employing calcium sensitive fluorescent dye, Fura-2 / AM, and cell injury was evaluated by determination of cellular ATP contents. Silica increased [Ca$^{2+}$], in a concentration-dependent manner in hepatocytes (10$^{-5}$ ~10$^{-2}$ M). Silica caused a biphasic increase in [Ca$^{2+}$], which was composed of an initial rapid rise and following sustained phase. $Ca^{2+}$ removal from the medium resulted in abolishment of initial and sustained phase of silica (10$^{-2}$ M)-induced [Ca$^{2+}$], in hepatocytes. The pretreatment with nifedipine (1 $\mu$M) attenuated silica-induced [Ca$^{2+}$], increases. Silica decreased cellular ATP contents in a dose-dependent manner. This silica-induced cell injury was attenuated by the pretreatment with EGTA (100 $\mu$M) and nifedipine (1 $\mu$M). This study suggests that the elevation of [Ca$^{2+}$], caused by silica may be due mainly to influx through a plasma membrane $Ca^{2+}$ channel and hepatotoxicity by silica relate with alteration of calcium homeostasis.ium homeostasis.

• 대한지역사회영양학회지
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• 제3권2호
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• pp.218-227
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• 1998

단백질 및 칼슘 수준이 체내 철분 및 아연의 평형에 미치는 영향을 알아보고자 건강한 젊은 여성 8명을 대상으로 20일간의 대사실험을 실시하였다. 실험대상자는 2일간의 적응 기간 후 저단백저칼슘식이 (44g 단백질, 422mg 칼슘), 고단백저칼슘식이 (85g 단백질, 365mg 칼슘), 고단백고칼슘식이 (84g 단백질, 727mg 칼슘)의 6일씩 각 실험식이를 섭취하였다. 각 식이 기간 후반 3일간의 대변 및 뇨를 수집하고 각 식이 기간이 끝난 후 공복시에 채혈하였다. 각 식이의 열량, 단백질, 칼슘, 철분 및 아연을 분석하고 대변과 뇨의 철분 및 아연을 분석하였으며 혈청중의 철분 및 아연 농도를 측정하여 비교하였다. 식이의 단백질 수준이 높아졌을 때 체내 철분과 아연의 흡수 및 평형이 유의적으로 증가되었으며(P<0.01) 식이의 칼슘 수준이 높아졌을 때 철분(p<0.01) 및 아연(p<0.05)의 흡수 및 평형은 감소되었다. 혈청의 철분이나 아연 농도는 저단백질식이보다 고단백질식이일 때 증가되는 경향이 있었다. 혈청의 철분 농도는 철분 평형보다는 섭취된 철분의 함량과 높은 양의 상관관계(r=0.99)를 나타냈다. 혈청과 두발의 아연 농도 간에는 상관관계를 볼 수 없었다. 본 연구 결과 식이중의 단백질 및 칼슘 섭취수준은 체내 철분 및 아연의 평형에 영향을 미친다는 것을 확인하였다. 따라서 우리 나라 영양권장량을 책정함에 있어서 이러한 영양소들의 대사를 재검토해야 하며 또한 최근 칼슘과 함께 철분을 강화시키는 몇몇의 시판 유제품이나 음료의 실제 유용성에 대한 평가도 필요하다고 사료된다.

• 대한환경공학회지
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• 제33권5호
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• pp.307-313
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• 2011

본 연구는 고농도의 불소가 함유된 LCD 폐수를 처리하는데 있어, 칼슘원에 따른 제거 효율과 경제성에 부합되는 조건을 도출하여 실제 현장에 적용하는데 목적이 있다. 이를 위하여 칼슘원으로 $CaCl_2$, $Ca(OH)_2$ 및 $CaCO_3$를 이용하여 각각 pH, 칼슘주입량, 반응시간 및 교반속도의 변화에 따른 특성을 관찰하였다. 그 결과 $CaCl_2$의 경우 pH 7, 칼슘주입량 0.4[Ca]/[F] (mol / mol), 1시간, 200 rpm으로 결정되었고, $Ca(OH)_2$의 경우 pH 7, 칼슘주입량 30 mL/L, 1시간, 200 rpm으로 결정하였으며, $CaCO_3$의 경우 pH 4, 칼슘주입량 30 mL/L, 1시간, 200 rpm으로 적용하는 것이 최적조건이라고 판단되었다. 그러나 현장의 상황에 따라 적용 조건의 변경이 가능하다.

• 한국지역사회생활과학회지
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• 제16권1호
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• pp.59-64
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• 2005

This study is to find out effects of hot water soluble extract from green tea, one of the Korean favorites, on the calcium metabolism and bone strength in body. To do so, calcium, phosphate, creatinine concentration and ALP activity in blood and the content of calcium and ash in the organ, the length, weight, strength in bone were measured. In addition, to find the calcium metabolism, the level of calcium intake, excretion, retention were measured. Twenty male Sprague-Dawley rats were divided into two groups and isoloated soy protein was provided as the source of protein and CaCO₃ was provided as the source of calcium. 0.5% hot water soluble extract from green tea was provided to the green tea groups and for the control group deionized water was provided. The results are as follows ; 1. There is no difference between the experimental groups in diet intake, weight gain, and the feed intake. 2. Feed efficiency ratio was low in the group which hot water soluble extract from green tea was provided. 3. There is no difference between groups the level of calcium, phosphorus, creatinine and ALP activity in serum. 4. There is no difference between groups weight, contents of ash and calcium in kidney and liver. 5. There is no difference between groups in calcium intake, absorption, excretion, and retention. 6. There is no difference between groups weight, length and strength in bone. In summary, when hot water soluble extract from green tea was provided with the amount of 150-200mg, which is taken when people generally drink as favorite tea, weight gain was reduced due to the decrease of feed efficiency ratio. However, it did not affect the availability of calcium in body at all. Thus, even if a big quantity of green tea powder or solid of hot green tea extract is not provided, the quantity obtained when people drink green tea lowers the feed efficiency ratio without reducing availability of calcium in body.

• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.379-390
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• 1998

In endodontic treatment, calcium hydroxide has been used as intracanal medicament. Although calcium hydroxide should be removed thoroughly before permanent root canal filling, no effective method for its removal has been reported. Because of irregularity of root canal walls, root curvatures and anatomic variations, it is insufficient to remove calcium hydroxide from the canal wall only by mechanical instrumentation Considering the chemical effects of irrigants on calcium hydroxide, $Ca^{++}$ dissolving effect from two calcium hydroxide products is investigated, using dis- tilled water, NaOCl, citric acid and EDTA. Vitapex$^{(R)}$ 0.1g and calcium hydroxide 0.03g were dissolved in distilled water, 5% NaOCl, 50% citric acid and 17% EDTA respectively, at 1, 3, 5, 10min. time interval. The solution was filtered using filter paper(pore size $5{\mu}m$) and $Ca^{++}$ concentration was determined by ion chromatography. The result were as follows : 1. Distilled water, NaOCl, citric acid and EDTA abstracted more $Ca^{++}$ from calcium hydroxide than Vitapex$^{(R)}$ except NaOCl 1, 5, 10 time interval. 2. EDTA and citric acid abstracted more $Ca^{++}$ from Vitapex$^{(R)}$ and calcium hydroxide than distilled water or NaOCl. The overall result support the view that water-based calcium hydroxide product is easily removed than oil-based calcium hydroxide product and EDTA, citric acid are more effective in $Ca^{++}$ elution than NaOCl or distilled water.