• 한국산학기술학회논문지
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• 제16권3호
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• pp.2301-2307
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• 2015

본 연구에서는 산업용수의 처리 및 운용 과정에서 중요한 문제점으로 지목되고 있는 탄산칼슘에 의한 스케일 형성을 제어하기 위해 고전압 임펄스 (High Voltage Impulse, HVI) 기술의 활용 가능성을 평가하고자 하였다. 전원부, 고전압발생부, 축전기, 스위치 및 임펄스발생기로 구성된 HVI를 제작하여 17kV의 고전압 펄스를 생성시켰다. 반응조에 $Ca^{2+}$을 포함하고 있는 인공 시료를 투입한 후 HVI를 인가하였다. HVI 접촉시간 5분 후에는 $Ca^{2+}$ 초기값의 3.0% 가량만 감소하였으나, 접촉시간 60분 후에는 약 13.7% 가량 감소하였다. HVI 인가로 인해 용액의 온도와 pH는 증가하였고 전기전도도는 탄산칼슘 석출로 인해 감소하는 것을 확인하였다. 칼슘 이온의 감소가 충분하지는 않았지만 전계의 세기 및 접촉시간에 따른 제거율에 간한 구체적인 정보가 얻어진다면, HVI 기술을 적용하여 $Ca^{2+}$ 이온을 탄산칼슘으로 미리 석출시켜 제거하는 연수화 (softening) 공정이나 탈염 기술로 활용할 수 있는 가능성을 확인하였다.

• Nutrition Research and Practice
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• 제6권5호
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• pp.396-404
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• 2012

The aim of the study was to investigate the inhibitory effects of calcium against intestinal cancer in vitro and in vivo. We first investigated the effects of calcium treatment in HCT116 and HT29 human colon cancer cells. At the concentration range of 0.8-2.4 mM, calcium significantly inhibited cell growth (by 9-29%), attachment (by 12-26%), invasion (by 15-31%), and migration (by 19-61%). An immunofluorescence microscope analysis showed that the treatment with calcium (1.6 mM) for 24 h increased plasma membrane ${\beta}$-catenin but decreased nuclear ${\beta}$-catenin levels in HT29 cells. We then investigated the effect of dietary calcium on intestinal tumorigenesis in $Apc^{Min/+}$ mice. Mice received dietary treatment starting at 6 weeks of age for the consecutive 8 weeks. The basal control diet contained high-fat (20% mixed lipids by weight) and low-calcium (1.4 mg/g diet) to mimic the average Western diet, while the treatment diet contained an enriched level of calcium (5.2 mg calcium/g diet). The dietary calcium treatment decreased the total number of small intestinal tumors (by 31.4%; P < 0.05). The largest decrease was in tumors which were ${\geq}$ 2 mm in diameter, showing a 75.6% inhibition in the small intestinal tumor multiplicity (P < 0.001). Immunohistochemical analysis showed significantly reduced nuclear staining of ${\beta}$-catenin (expressed as nuclear positivity), but increased plasma membrane staining of ${\beta}$-catenin, in the adenomas from the calcium-treated groups in comparison to those from the control group (P < 0.001). These results demonstrate intestinal cancer inhibitory effects of calcium both in human colon cancer cells and $Apc^{Min/+}$ mice. The decreased ${\beta}$-catenin nuclear localization caused by the calcium treatment may contribute to the inhibitory action.

• Geomechanics and Engineering
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• 제17권5호
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• pp.465-473
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• 2019

Biocementation due to the microbially induced calcium carbonate precipitation (MICP) process is a potential technique that can be used for soil improvement. However, the effect of biocementation may be affected by many factors, including nutrient concentration, bacterial strains, injection strategy, temperature, pH, and soil type. This study investigates mainly the effect of chemical concentration on the formation of calcium carbonate (e.g., quantity, size, and crystalline structure) and unconfined compressive strength (UCS) using different treatment time and chemical concentration in the biotreatment. Two chemical concentrations (0.5 and 1.0 M) and three different treatment times (2, 4, and 8 cycles) were studied. The effect of chemical concentrations on the treatment was also examined by making the total amount of chemicals injected to be the same, but using different times of treatment and chemical concentrations (8 cycles for 0.50 M and 4 cycles for 1.00 M). The UCS and CCC were measured and scanning electron microscopy (SEM) analysis was carried out. The SEM images revealed that the sizes of calcium carbonate crystals increased with an increase in chemical concentrations. The UCS values resulting from the treatments using low concentration were slightly greater than those from the treatments using high concentration, given the CCC to be more or less the same. This trend can be attributed to the size of the precipitated crystals, in which the cementation efficiency increases as the crystal size decreases, for a given CCC. Furthermore, in the high concentration treatment, two mineral types of calcium carbonate were precipitated, namely, calcite and amorphous calcium carbonate (ACC). As the crystal shape and morphology of ACC differ from those of calcite, the bonding provided by ACC can be weaker than that provided by calcite. As a result, the conditions of calcium carbonate were affected by test key factors and eventually, contributed to the UCS values.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.217-220
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• 2001

Enzyme production of calcium stearate was attempted by lipase, hydrogenated beef tallow that contain high level of stearic acid was used by substrate. 90% of hydrogenated beef tallow was converted into calcium stearate in 2.5hr. Calcium stearate that was produced by this method was purified and recovered through new method and this purified and recovered calcium stearate was compared with standard calcium stearate through FT- IR. This result showed the possible replacement of conventional process into enzymetic reaction process.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1994년도 춘계학술대회 and 제3회 신약개발 연구발표회
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• pp.217-217
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• 1994

Calcium entry blockers, capable of inhibiting transmembrane influx of extracellular calcium through specific calcium channels, are useful drugs in the treatment of angina pectoris, hypertension, cardiac arrythmia, and various cardiovascular disorders. Compounds having isoquinoline structures have recently been reported to possess calcium antagonistic action. Therefore, in the present study, we have attempted to synthesize some isoquinoline and related compound.; in order to search for potentially effective chemicals acting on cardiovascular system, and evaluated their pharmacological properties focusing on calcium antagonistic actions. Almost all of the compounds so far synthesized, had inhibitory action against phenylephrine or high potassium-induced contraction in vascular smooth muscle with different degrees of potencies depending on their structures, However, some of tetrahydroisoquinoline analogs showed directly inhibit calcium current in isolated rabbit cardiac myocytes examined by patch clamp techniques. The pharmacological properties of these compounds need more intensive investigation as to whether these chemicals may have developed as a new cardiovascular active drugs. Therefore, we are now under investigation of the mechanism of action of these compounds.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.220-228
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• 2018

In this study, we found a simple surface biofunctionalization of biphasic calcium phosphate (BCP) based on the high affinity between alendronate and the calcium ions of BCP, and the strong interaction between heparin and bone morphogenic protein-2 (BMP-2). The biofunctionalized BCP did not be precipitated well and display a remarkable enhancement of osteogenic activity of human adipose-derived stem cells by showing increased alkaline phosphatase (ALP), calcium deposition and osteogenic-related genes (i.e., Runx-2, ALP, osteocalcin, and osteopontin), and bone regeneration in the calvarial defect model. Therefore, this simple surface technique can be used to easily functionalize various calcium phosphates.

• 대한수의학회지
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• 제21권1호
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• pp.51-58
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• 1981

Two experiments were conducted to establish a program for the prevention of swine parakeratosis occurred recently in Korea. In the first experiment, 11 rations which were considered to be related clinico-pathologically to the incidence of parakeratosis and 5 rations not to be related were collected at farms during the period from June, 1979 to December, 1980. In addition, 23 commercial rations and 10 ingredients were also collected at feed dealers or farms. The feed samples were analyzed for calcium, zinc and unsaturated fatty acid. In the second experiment, the efficiencies of adding zinc carbonate (150mg/kg diet) with or without soybean oil (5ml/kg diet) to two control rations were tested using 20 weanling pigs. One of the control rations had low zinc (41mg/kg) and normal calcium (0.64%) and the other low zinc (57mg/kg) and high calcium (1.42%). The results obtained are as follow: 1. Content of zinc in the rations induced parakeratosis ranged from 35 to 80mg/kg with a mean of 49mg/kg; whereas those of rations not induced ranged from 97 to 182mg/kg with a mean of 182mg/kg. The difference between two means was highly significant (p<0.01). 2. The calcium content in rations related to parakeratosis was ranged from 0.56 to 1.80% with a mean of 1.30% whereas that of not related was ranged from 0.63 to 1.37% with a mean of 1.07%. The highly significant difference of calcium content between two rations were recognized (p<0.01). The calcium contents of both rations were markedly higher than that of generally recommended value of 0.40~0.80%. 3. The contents of unsaturated fatty acid in induced rations was a mean of 4.42% and it was significantly lower (p<0.01) compared with those in not induced rations with a mean of 6.70%. The content of unsaturated fatty acid of commercial rations was ranged from 5.25 to 7.81% with a mean of 6.29%. 4. Zinc content of 15 commercial ration samples among 23 were less than 97mg/kg and 21 rations contained more than 1.03% of calcium. 5. Addition of zinc carbonate to the two control rations which are low in zinc content or high in calcium content were resulted in preventive effect on the incidence of swine parakeratosis. 6. It may be concluded that the incidence of swine parakeratosis was closely related to the low zinc, excess calcium and low unsaturated fatty acid in rations, most of the commercial rations contained low in zinc and high in calcium as compared with the recommended contents. Content of Unsaturated fatty acids in the commercial rations, however, were sufficient for the prevention of parakeratosis in swine.

• 대한수의학회지
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• 제25권1호
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• pp.41-48
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• 1985

In the present studies, the effects of dietary high-potassium and high-urea on the metabolism of magnesium, calcium and potassium were checked as an aid to clarify the pathogenesis of hypomagnesaemia(so-called grass tetany) in ruminant. A total of 5 Korean native female goats kept in metabolic cage were received high-potassium(Mg: 0.25%, Ca: 0.94%, K: 5.41%), high-urea(Mg: 0.25%, Ca: 0.94%, K: 0.72%) or control(Mg: 0.25%, Ca: 0.94, K: 0.72%) ration for 15 or 21 days. Daily intakes, fecal and urinary excretions and serum concentrations of magnesium, calcium and potassium were measured with an atomic absorption spectrophotometer. The results obtained were summarized as follows: In high-potassium group, absorption, urinary excretion and serum concentration of magnesium were significantly (p<0.01, p<0.01 and p<0.05 respectively) decreased compared with the control group. On the other hand, the body retention was significantly (p<0.01) increased. However, no clinical symptom of hypomagnesaemic tetany was observable throughout the experimental period. No significant effects on the metabolism and seurm content of calcium were detected in the high-potassium group. In the high-potassium group, significant increase in absorption (p<0.01), urinary excretion (p<0.05) and body retention (p<0.01) of potassium were recognized. However, no significant difference in the concentration of serum was observable between the two groups. In high-urea group, no significant difference in the metabolism of magnesium and potassium or in the serum content were recognized compared with the control group. In high-urea group, tthe absorption, urinary excretion, body retention and serum content of calcium were decreased compared with the control group.

• 한국항해항만학회지
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• 제39권6호
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• pp.523-528
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• 2015

본 연구에서는 붕소함유 인공염수(간수)를 수산화칼슘으로 포화시켜 calcium borate를 합성하는 반응에서, 첨가하는 황산이 미치는 영향을 알아보았다. 다양한 조건(반응온도, 반응시간, 가열반응 후 방랭온도)에서 calcium borate 합성을 시도하였고, 각 조건에서 황산 첨가유무에 따른 calcium borate의 회수율과 순도 변화를 알아보았다. XRD 분석을 통해 황산의 첨가유무에 상관없이 calcium borate($Ca_2B_2O_5{\cdot}H_2O$)가 생성되었음을 확인하였고, 황산을 첨가하면 부산물로 황산칼슘(($CaSO_4{\cdot}0.5H_2O$) 이 생성되었다. 황산을 첨가하지 않았을 때, 실험한 모든 반응온도와 반응시간 조건에서 calcium borate의 회수율과 순도가 황산을 첨가했을 때보다 더 높았다. 황산을 첨가하면 수산화칼슘의 용해도는 높아지지만, 부산물로 생성되는 황산칼슘이 calcium borate의 생성을 방해하여 그 회수율과 순도가 낮아진다고 판단된다. 본 연구에서는 붕소함유(500 mg-B/L) 인공염수(간수)에 황산을 첨가하지 않고 수산화칼슘으로 포화시켜서 $80-105^{\circ}C$에서 10분 이내로 가열하여 calcium borate를 합성하였고, 그 회수율과 순도는 각각 최대 80 %, 96 %로 매우 높았다.

• 한국치위생학회지
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• 제17권2호
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• pp.283-294
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• 2017

Objectives: The purpose of the study was to investigate the effect of calcium concentration in saliva on dental caries activity after consuming calcium. Methods: A total of 59 adult women aged 20 to 40 years were surveyed for calcium intake. The daily average calcium intake was analyzed through dietary records of the subjects. The subjects were divided into two groups based on daily average calcium intake. Salivary pH and concentrations of minerals in the saliva were obtained from A group and B group. Calcium ($Ca^{2+}$) and magnesium ($Mg^{2+}$) concentrations in saliva were measured by HPLC-Ion chromatography using 15 mM sulfuric acid. The dental caries activity test was quantified by salivary buffer capacity test and plaque pH test. Results: The mean $Ca^{2+}$ concentrations of A group was $12.75{\mu}g/m$, the mean $Ca^{2+}$ concentrations in the B group was $16.30{\mu}g/mL$ (p<0.05) and respectively, $Mg^{2+}$ concentrations were found to be $0.48{\mu}g/mL$ and $0.51{\mu}g/mL$. Calcium intake and calcium concentration in saliva showed a significant correlation (r=0.380). Conclusions: The mean $Ca^{2+}$ concentrations in saliva was higher in the high calcium intake group. Therefore, calcium intake in saliva was correlated with dental caries.