• 대한수의학회지
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• 제48권3호
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• pp.243-250
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• 2008

A calmodulin-dihydrofolate reductase (DHFR) sandwich fusion protein was generated by insertion of calmodulin into the $\beta$-bulge region of DHFR to observe the effects of structurally constraining the calmodulin structure. The calcium binding properties of the sandwich protein were almost identical to calmodulin. Similar to calmodulin ($10.7 {\mu}M$), the sandwich protein bound four equivalents of calcium, with half saturation ($K_{0.5}$) observed at a [$Ca^{2+}$] of $8{\mu}M$. However, nicotinamide adenine dinucleotide (NAD) kinase activation property of the sandwich protein was lower than that of calmodulin. The sandwich protein activated NAD kinase, but to only half of the level obtained with calmodulin. The K 0.5 for both calmodulin and the sandwich protein were approximately the same (1-2 nM). Methylation analyses of the sandwich protein show that insertion of calmodulin into DHFR results in a large decrease in methylation. The $V_{max}$ observed with the sandwich protein (95 nmole/min/ml) was only 22% of the value observed with calmodulin (436 nmol/min/ml) in the presence of calcium. Addition of trimethoprim to the reaction significantly inhibited the observed methylation rate. Overall, the data suggest that the insertion of calmodulin into the DHFR structure has little effect on calcium binding by the individual lobes of calmodulin, but may constrain the lobes in a manner that results in altered interaction with the calmodulin-dependent proteins, and severely perturbed the methyltransferase recognition site.

• Restorative Dentistry and Endodontics
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• 제10권1호
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• pp.71-83
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• 1984

The purpose of this study was to evaluate the transmission spectrum of the set calcium hydroxide dental cement (Dycal, L.D. Caulk Co. Milford, Del.) Cement was prepared for A T R spectra at a low powder-to-liquid ratio of 3.0gm/ml in order to retard the reaction and facilitate the manipulation of loading the cement into the cell. Spectra were recorded on an I R Spectrophotometer (MX-1, FT) at an agle of incidence of 55. The A T R cell was a RIIc Model TR5 with a hemisperical KRS-5 (Thallium-Bromide-Iodide). A spectrum was recorded within 3 minutes. Further spectra were recorded after 5,10,30 minutes and 1,5,24, 72 hours. The results were as follows; 1. The setting reaction between acid paste and base past would take place fastly within 10 minutes after mix, and that would be slow until 72 hours after mix. 2. In the set cements, some methyl salicylate and calcium hydroxide remained unreacted until 72 hours after mix. 3. The setting reaction and the reaction rate occuring at the surface and in the bulk cements were similar. 4. The chelates were bound together between calcium hydroxide and methyl salicylate.

• 한국식생활문화학회지
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• 제17권5호
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• pp.584-593
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• 2002

The purpose of this study was to evaluate the diet quality of the menus delivered by 17 free meal service centers for the low-income home-bound elderly in Chung- cheong buk-Do. Statistical data analysis was compleleted using the SPSS package program for descriptive analysis, T-test, and ANOVA. The meals offered by free meal service centers were not met the 1/3 recommended dietary allowances in calcium and vitamin $B_2$. There were significant differences between dependent variables(nutrient content, nutrient density, nutrient deficiency, NAR, MAR, food group intake patterns) and independent variables (operation type, operation status, operation period, nutritionist, food cost).

• 한국식품영양과학회지
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• 제28권2호
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• pp.326-332
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• 1999

In order to develope useful components and to apply in food additives, various components in the leaves of baechohyang were determined according to picking date. Moisture and ash were reached to 74~82%, 1.5~3.4%, respectively, and major sugars were fructose, glucose, sucrose, and maltose. Glutamic, aspartic acid, and leucine constituted the main component amino acids and their contents were relatively higher in the samples of summer and young leaves. Among free amino acids, histidine showed the highest components and methionine were the lowest. Potassium, calcium, and sodium were main mineral components. The content of ascorbic acid were 6.6~9.2mg% and seasonal variations were negligible. Muture leaves contained more polyphenols as much as 108~181mg% and the amount of bound fractions were much more. Periodic evaluation of phenolic compounds were made and major components of bound fractions were caffeic, syringic, and ferulic acid.

• Parasites, Hosts and Diseases
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• 제42권4호
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• pp.185-193
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• 2004

Toxoplasma gondii is an obligate intracellular protozoan parasite, which invades a wide range of hosts including humans. The exact mechanisms involved in its invasion are not fully understood. This study focused on the roles of $Ca^{2+}$ in host cell invasion and in T. gondii replication. We examined the invasion and replication of T. gondii pretreated with several calcium modulators, the conoid extrusion of tachyzoites. Calmodulin localization in T. gondii were observed using the immunogold method, and $Ca^{2+}$ levels in tachyzoites by confocal microscopy. In light microscopic observation, tachyzoites co-treated with A23187 and EGTA showed that host cell invasion and intracellular replication were decreased. The invasion of tachyzoites was slightly inhibited by the $Ca^{2+}$ channel blockers, bepridil and verapamil, and by the calmodulin antagonist, calmidazolium. We observed that calcium saline containing A23187 induced the extrusion of tachyzoite conoid. By immunoelectron microscopy, gold particles bound to anti-calmodulin or anti-actin mAb, were found to be localized on the anterior portion of tachyzoites. Remarkably reduced intracellular $Ca^{2+}$ was observed in tachyzoites treated with BAPTA/AM by confocal microscopy. These results suggest that host cell invasion and the intracellular replication of T. gondii tachyzoites are inhibited by the calcium ionophore, A23187, and by the extracellular calcium chelator, EGTA.

• 대한가정학회지
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• 제30권1호
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• pp.99-113
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• 1992

This study was performed to investigate the effect of dietary protein and calcium levels on cadmium detoxication in rats. Seventy male Sprague-Dawley rats weighing 208 $\pm$ 19 g were blocked into 10 groups of 7 animals according to body weight. Five groups were fed 15% protein-0.6% calcium diet with 100ppm cadmium in drinking water for first 15days and the other 5groups fed same diet without cadmium in drinking water for same period and served as controls. After this 15-day intoxication period, each one of cadmium intoxication and control groups were fed each of 4 kinds of detoxifying diets different with protein(40%, 15%) and calcium(1.3%, 0.6%) levels without cadmimum in drinking water for following 15 days of detoxifying period. Results were summarized as follows: 1) Food intake, body weight gain, F.E.R. and weights of liver, kidney and femur were increased by detoxifying diets and high protein diet was most effective in weight gains of liver and kidney. 2) When cadmium and metallothionein contents of initial intoxication group and those of all detoxication groups were compared, cadmium and metallothionein contents in the liver were not changed, but those in kidney increased, and those in intestine decreased markedly. 3) Only dietary protein level affected cadmium and metallothionein distribution among organs, and cadmium contents of whole blood, liver, kidney and femur were lower in high protein diet, but metallothionein contents in liver and kidney were higher in high protein diet. 4) Gel filtration chromatogram showed that most of cadmium in the cytosol was bound to metallothionein fractions in high protein-high calcium group. Results obtained indicated that high protein diet was effective in cadmium detoxication by increasing the induction of metallothionein synthesis. But high calcium diet did not play a role in cadmium detoxication.

• Journal of Radiation Protection and Research
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• 제22권1호
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• pp.9-14
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• 1997

카이토산은 무독성 천연착화제의 일종으로 방사성스트론튬의 마우스체내축적을 감소시킨다고 알려져 왔다. 스트론튬은 칼슘이온과 비슷한 화학적 특성을 가지고 있으며, hydroxyapatite에 쉽게 결합하여 제거하기가 어렵다. 본 실험에서는 카이토산과 칼슘이온을 처리하였을 경우 방사성스트론튬의 체외배출 효과를 비교해 보았다. 1% 카이토산 혹은 칼슘을 일반식이와 혼합하여 섭취시킨 후 방사성스트론튬을 관을 통해 구강으로 주입하였고, 방사성스트론튬 오염후 1% 카이토산 혹은 칼슘용액, 그리고 1% 카이토산과 칼슘을 혼합한 용액을 각각 구강주사하였다. 대조군은 카이토산 또는 칼슘을 처리하지 않았으며, 각각의 실험군은 10마리씩 7일간 관찰하였다. 모든 실험군에서 대조군에 비해 변과 오줌 등을 통한 스트론튬의 체외배출이 높게 나타났으며 (p<0.01), 골조직 등의 침착율도 낮게 나타났다 (p<0.01). 칼슘 투여군과 카이토산 투여군 간에는 유의한 차이가 없었다. 카이토산 단독투여 군과 칼슘과 카이토산 동시 투여군 사이에는 방사성스트론튬 배설율에 차이가 없었다. 결론적으로, 칼슘은 카이토산과 동일하게 입으로 오염된 방사성스트론튬 제거에 효과가 있을 것으로 사료된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.565-566
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• 2009

Supplementary cementing materials (SCM), such as silica fume, slag, and low-calcium fly ash, have been widely used as mineral admixtures in high strength and high performance concrete. Due to the chemical and physical effect of SCM on hydration, compared with Portland cement, hydration process of cement incorporating SCM is much more complex. This paper presents a numerical hydration model which is based on multi-component concept and can simulate hydration of cement incorporating SCM. The proposed model starts with mixture proportion of concrete and considers both chemical and physical effect of SCM on hydration. Using this proposed model, this paper predicts the following properties of hydrating cement-SCM blends as a function of hydration time: reaction ratio of SCM, calcium hydroxide content, heat evolution, porosity, chemically bound water and the development of the compressive strength of concrete. The prediction results agree well with experiment results.

• 농업과학연구
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• 제37권2호
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• pp.209-216
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• 2010

In order to understand the effects of a single or combined treatments of 1-MCP($1{\mu}L/L$) and $CO_2$(100%) on the firmness of melting type peach fruit(cv. Chunjungdo), fruit were harvested at commercial maturity and examined physiological changes including flesh firmness during 10 days of shelf-life. Firmness loss of fruit was delayed by both single and combined treatments of 1-MCP and $CO_2$. The treatment of 1-MCP was more effective than $CO_2$ treatment but no additive effective on firmness retention was found in the combined treatment. The upsurge of ethylene evolution occurred 5 days of shelf-life in air treated control but ethylene evolution gradually increased in fruit treated by 1-MCP and 1-MCP+$CO_2$. The suppression of ethylene evolution seemed stronger in $CO_2$ treatment. The respiration of fruit significantly inhibited up to 10 days except control where climacteric increase of respiration was found at 10 days of shelf-life. A molecular shift of pectic polymers(an increase of chelator soluble pectins and decrease of water soluble pectins) was induced by both 1-MCP and $CO_2$ treatments. An increase of water soluble pectins was coincident with firmness loss. The delay of firmness loss seemed to be associated with the migration of calcium to wall matrix, especially pectins, resulting in the increase of wall bound calcium. The polygalacturonase activity was significantly reduced by 1-MCP alone 1 day after treatment and increased to similar level of activity 5 days after treatment compared to other treatment except air treated control whereas pectin methylesterase activity seemed not to be affected by both 1-MCP and $CO_2$ treatments. Thus, the molecular shift of pectic polymers appeared not to be related with pectin methylesterase. Further study is required to clarify the softening mechanism associated with molecular shift of pectic polymers and the inter- or intra-cellular movement of calcium ions induced by postharvest treatments of 1-MCP and $CO_2$.

• 유기물자원화
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• 제29권4호
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• pp.41-46
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• 2021

초음파/과산화칼슘 처리(US/CaO₂)에 따른 하수슬러지의 가용화 정도를 확인하고자 과산화칼슘의 주입량(0.01, 0.02, 0.03, 0.04 및 0.05 g CaO₂/g VSS)에 따른 처리 효율을 비교하였다. 가용화의 주요 지표인 VSS 감량화율, 가용화율, SCOD/VSS, SCOD 증가속도 및 미생물의 세포벽이 파쇄되었는지 확인하기 위하여 LB-EPS와 TB-EPS를 측정하였다. 실험결과, US/CaO₂(0.05 g CaO₂/g VSS) 조건에서 가용화율은 50.7%로 US 처리(23.4%)보다 높은 효율을 나타내었으며, VSS 감량화율도 US/CaO₂(0.05 g CaO₂/g VSS) 조건에서 17.7%, US 조건에서는 7.1%로 가용화율과 유사한 경향을 나타내었다. 조사시간 10분부터 90분까지 SCOD의 증가속도는 US/CaO₂(0.02 g CaO₂/g VSS) 조건에서 0.0151 min^-1으로 가장 빠른 속도를 나타내었다. TB-EPS는 US/CaO₂(0.05 g CaO₂/g VSS)조건에서 59.0%, US 조건에서 36.4% 감소하였다. TB-EPS는 초기 10분동안 빠르게 감소하였으며, 이후부터 상대적으로 완만하게 줄어드는 것을 확인할 수 있었다. 과산화칼슘의 주입량에 따른 TB-EPS의 감소량은 큰 차이가 없는 것으로 나타났다.