• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2769-2773
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• 2013

Red phosphors $Ca_{(1-1.5x)}Eu_xWO_4$ and $Ca_{(1-2x)}Eu^_xNa_xWO_4$ were synthesized with various concentrations x of $Eu^{3+}$ ions by using a solid-state reaction method. The crystal structure of the red phosphors were found to be a tetragonal scheelite structure with space group $I4_1/a$. X-ray diffraction (XRD) results show the (112) main diffraction peak centered at $2{\theta}=28.71^{\circ}$, and indicate that there is no basic structural deformation caused by the vacancies ${V_{Ca}}^{{\prime}{\prime}}$ or the $Eu^{3+}$ (and $Na^+$) ions in the host crystals. Densities of $Ca_{(1-1.5x)}Eu_xWO_4$ were measured on a (helium) gas pycnometer. Comparative results between the experimental and theoretical densities reveal that $Eu^{3+}$ (and $Na^+$) ions replace the $Ca^{2+}$ ions in the host $CaWO_4$. Also, the photoluminescence (PL) emission and photoluminescence excitation (PLE) spectra show the optical properties of trivalent $Eu^{3+}$ ions, not of divalent $Eu^{2+}$. Raman spectra exhibit that, without showing any difference before and after the doping of activators to the host material $CaWO_4$, all the gerade normal modes occur at the identical frequencies with the same shapes and weaker intensities after the substitution. However, the FT-IR spectra show that some of the ungerade normal modes have shifted positions and different shapes, caused by different masses of $Eu^{3+}$ ions (or $Na^+$ ions, or ${V_{Ca}}^{{\prime}{\prime}}$ vacancies) from $Ca^{2+}$.

• 대한화학회지
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• 제53권3호
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• pp.272-278
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• 2009

$Ca^+-(CO)_n$,과 $Ca^+-(CO_2)_n$ (n=1,2) complex에 대한 구조와 결합 에너지를 MP2/6-311++G(2d,p) 방 법과 B3LYP/6-311++G(2d,p) 방법에 의해 계산하였고 vibrational frequencies도 계산하였다. $Ca^+-(CO)_n$의 경우 C-bonded complex와 O-bonded complex가 다 가능함을 보였고, $Ca^+-(CO)_2$에서는 선형과 $C_{2v}$ 형태가 나타남을 볼 수 있었으며 더 안정한 형태는 $C_{2v}$ 구조로 밝혀졌다. $Ca^+-(CO_2)_2$에서도 선형과 $C_{2v}$ 형태를 볼 수 있는데 이 경우는 선형이 근소한 에너지 차이로 더 안정한 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제25권8호
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• pp.1371-1379
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• 2015

The Ca_v1.2 Ca²⁺ channel is essential for cardiac and smooth muscle contractility and many physiological functions. We mutated single, double, and quadruple sites of the four potential Asn (N)-glycosylation sites in the rabbit Ca_v1.2 into Gln (Q) to explore the effects of Nglycosylation. When a single mutant (N124Q, N299Q, N1359Q, or N1410Q) or Ca_v1.2/WT was expressed in Xenopus oocytes, the biophysical properties of single mutants were not significantly different from Ca_v1.2/WT. In comparison, the double mutant N124,299Q showed a positive shift in voltage-dependent gating. Furthermore, the quadruple mutant (QM; N124,299,1359,1410Q) showed a positive shift in voltage-dependent gating as well as a reduction of current. We tagged EGFP to the QM, double mutants, and Ca_v1.2/WT to chase the mechanisms underlying the reduced currents of QM. The surface fluorescence intensity of QM was weaker than that of Ca_v1.2/WT, suggesting that the reduced current of QM arises from its lower surface expression than Ca_v1.2/WT. Tunicamycin treatment of oocytes expressing Ca_v1.2/WT mimicked the effects of the quadruple mutations. These findings suggest that Nglycosylation contributes to the surface expression and voltage-dependent gating of Ca_v1.2.

• Applied Biological Chemistry
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• 제37권6호
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• pp.421-426
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• 1994

$CaCO_3$가 청국장 메주 발효에 미치는 영향을 구명하고자 $CaCO_3$ 0, 0.01, 0.1, 1%씩 되게 각각 첨가한 청국장 메주에 B. subtilis를 접종하여 청국장 메주 발효 중의 성분 및 단백질 분해 효소력과 아미노산, 비타민 B복합체의 함량을 조사하였다. 발효중 $CaCO_3$첨가구의 품온은 대조구보다 높았으며, 적정산도는 $CaCO_3$첨가구에서 첨가 농도가 높아짐에 따라 대조구보다 감소하였고, 단백질 분해효소력 및 아미노태 질소함량은 0%<0.01%<0.1%<1%의 $CaCO_3$ 첨가 순으로 $CaCO_3$첨가구가 높았다. 아미노산 함량은 시험구 모두 증가하였으나, $CaCO_3$첨가구와 대조구간의 큰 차이는 없었다. 그러나 vitamin B복합체의 함량은 $CaCO_3$첨가구가 대조구보다 증가하였으며, 그중 0.01% 첨가구가 가장 높았다.

• 한국식품조리과학회지
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• 제33권1호
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• pp.1-8
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• 2017

Purpose: The aim of this study was to evaluate the quality characteristics of rice nutritional bars prepared by adding Chinese artichoke (CA) powder to the rice powder. Methods: CA rice nutritional bars were prepared with various levels of CA powder (0%, 5%, 10%, 15%, and 20%) and designated as CA0 (without CA powder), CA5, CA10, CA15, and CA20, respectively. The total phenolic content, DPPH free radical scavenging activity, moisture content, pH, baking loss rate, leavening rate, volume, color, texture analysis, and sensory evaluations of rice nutritional bars were performed. Results: The total phenolic content and DPPH free radical scavenging activity exhibited an increase with increase in the substitute amount of CA powder. The results showed that the pH of rice nutritional bars decreased in all sample groups as the content of CA powder increased. The volume of the sample group with CA powder was higher than that of CA0. As the content of CA powder increased, lightness of the rice nutritional bars crumbs decreased while redness and yellowness increased. The texture analysis of rice nutritional bars showed that hardness, gumminess, and chewiness were the highest in CA0 while springiness and cohesiveness were the lowest in CA0. With respect to characteristic intensity rating, the taste, flavor, and softness of rice nutritional bars increased with increasing amounts of CA powder. In terms of consumer acceptability, CA15 and CA20 received the highest scores with respect to texture. Conclusion: Therefore, the results of this study indicate that replacing 15% of the rice powder with CA led to an efficient enhancement in the antioxidant and nutritional values of rice nutritional bars as well as the sensory quality.

• Journal of Nutrition and Health
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• 제35권1호
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• pp.45-52
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• 2002

This study was to investigate 1) the correlation of serum Ca, with depression and anxiety ; and 2) the effect of Ca intake on those symptoms. The subjects were three females and two males who were 53-66 years old with the severe subjective symptoms of depression and anxiety. They have taken more than twice Ca of RDA(recommended dietary allowances for Koreans) daily for 6 months(dietary treatment). The prestudy Ca intake of the subjects was low: 60% of RDA for Koreans. Their serum Ca concentration was also low: 6.67 $\pm$ 0.15mg/d1 before the dietary treatment. They expressed severs depression and anxiety, with high self scores in a psychological test. Their serum Ca concentration increased to 8.32 $\pm$ 0.17mg/dl after six months of dietary treatment, while the symptoms of depression and anxiety decreased significantly after two months and nearly disappeared after six months. This result seemed to be an effect of the dietary high Ca intake. Serum Ca and the psychological states of depression and anxiety correlated negatively, and the coefficients of determination were high in the results of linear regression analysis of depression and anxiety by serum Ca. Therefore the serum Ca concentration could be a good marker to predict depression or anxiety relatively well. The continuous high Ca intake could decrease the probability of developing depression or anxiety and mitigate their symptoms because serum Ca concentration increased, while the state of depression and anxiety decreased with the increased Ca intake.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.371-374
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• 2004

저온동시 소성용(low temperature co-fired ceramics, LTCC) 마이크로파 유전체을 만들기 위해 $Ca(Li_{1/4}Nb_{3/4})O_3$ 마이크로파 유전체 세라믹스에 zinc-borosililcate glass를 첨가하여 소결 특성과 마이크로파 유전 특성을 조사하였다. $Ca(Li_{1/4}Nb_{3/4})O_3$과 $0.7Ca(Li_{1/4}Nb_{3/4})O_3-0.3CaTiO_3$에 zinc-borosilicate를 $5{\sim}30wt%$ 첨가하여 소결한 결과 $875{\sim}925^{\circ}C$에서 동시 소성이 가능한 것으로 확인되었으며 zinc-borosilicate glass의 함량이 증가할수록 저온에서 소성이 가능하였지만 과량의 액상과 2차상이 형성되면서 유전율과 품질계수가 저하되는 경향을 나타내었다. $Ca(Li_{1/4}Nb_{3/4})O_3$에 5wt%의 zinc-borosilicate를 첨가하여 $900^{\circ}C$에서 소성한 결과 가장 우수한 유전 특성$(\epsilon_r=17.45,\;Q{\times}f_0=5487)$을 나타내었고, 유전율을 높이기 위해 $CaTiO_3$를 0.3mol% 첨가한 $0.7Ca(Li_{1/4}Nb_{3/4})O_3-0.3CaTiO_3$에 10wt%의 zinc-borosilicate를 첨가하여 $925^{\circ}C$에서 소성한 결과 가장 우수한 유전특성$(\epsilon_r=44.92,\;Q{\times}f_0=5567)$을 나타내었다.

• 한국콘텐츠학회논문지
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• 제2권3호
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• pp.146-151
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• 2002

전자빔 증착장비를 이용하여 $Ca_{1-x}$Sr$_{x}$S:CuCl TFEL소자를 제작한 후 발광특성을 평가하였다. 형광체 모체 $Ca_{1-x}$Sr$_{x}$S는 CaS와 SrS 미분말을 혼합, 성형하여 제작하였으며, 발광중심체 CuCl은 0.2 at%를 첨가시켰다. CaS:CuCl TFEL 소자의 휘도(L$_{30}$)와 최대 발광파장은 각각 9.5 cd/$m^2$와 492 nm였으며 SrS:CuCl TFEL 소자의 휘도(L$_{30}$)와 최대 발광파장은 각각 633 cd/$m^2$와 500 nm였다. SrS에 CaS가 첨가된 $Ca_{1-x}$Sr$_{x}$S:CuCl TFEL 소자에서 청색 색순도는 좋아졌으나, 휘도와 효율은 급격히 감소하였다.

• Toxicological Research
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• 제18권4호
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• pp.355-362
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• 2002

Pathophysiological elevation of intracellular calcium concentration ($[Ca^{2+}]_1$) in the neuron has been considered as an important responsible factor in the neuronal cell damages. However the mechanism of increase of $[Ca^{2+}]_1$ and the relationship between $[Ca^{2+}]_1$ level and cytotocixity have not been fully demonstrated. In the present study, real-time alteration of $[Ca^{2+}]_1$and cellular response (cell damages) in the pheochromocytoma cells (PC12) stimulated by glutamate were investigated. Glutamate dose dependently decreased cell viability determined propidium iodide fluorescence method and morphology change. Conversely related with cell damages, glutamate dose dependently increased the level of［Ca$^{2+}$］$_{i}$ . To investigate the mechanism of glutamate-induced increase of $[Ca^{2+}]_1$,$[Ca^{2+}]_1$, was first measured in the cell cultured in calcium free media and in the presence of dantrolene, an inhibitor of calcium release from ryanodine receptor located in endoplasmic reticulum (ER). Similar to the increase$[Ca^{2+}]_1$ in the calcium-containing media, glutamate dose dependently increased $[Ca^{2+}]_1$ in the cell cultured in free calcium media. However pretreatment (2 hr) with 20~50 $\mu\textrm{M}$ dantrolene substantial lowered glutamate-induced increase of $[Ca^{2+}]_1$, suggesting that release of calcium from ER may be major sourse of increase of $[Ca^{2+}]_1$ in PC12 cells. Dantrolene-induced inhibition of $[Ca^{2+}]_1$ resulted in recovery of cytotoxicity by glutamate. Relevance of N-methy-D-aspartate (NMDA) receptor, a type of glutamte receptor on glutamate-induced incense of $[Ca^{2+}]_1$,$[Ca^{2+}]_1$ was also determined in the cells pretreated (2 hr) with NMDA receptor antagonist MK-80l. Glutamate-induced increase of $[Ca^{2+}]_1$ was reduced by MK-801 dose dependently. Furthermore, glutamate-induced cytotoxicity was also prevented by MK-80l. These results demonstrate that glutamte increase $[Ca^{2+}]_1$ dose dependently and thereby cause cytotoxicity. The increase of $[Ca^{2+}]_1$ may release from ER, especially through ryanodine receptor and/or through NMDA receptor Alteration of calcium homeostasis through disturbance of ER system and/or calcium influx through NMDA receptor could contribute glutamate-induced cell damages.s.

• 한국광물학회지
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• 제13권4호
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• pp.221-230
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• 2000

이성분 희토류 원소로 치환된 4종류의 합성불화인회석(synthetic fluorapatite) (Ap49: La+Gd, Ap50:Ce+Dy, Ap51: Pr+Er, Ap54: Eu+Lu; $Ca{10-x-2y}$ $Na_{y}$ $REE_{x+y}$($P_{1-x}$ //$Si_{x}$ $_{4}$)$_{6}$ $F_{2}$, x=0.13~0.12, y=0.26~0.42)을 대상으로 X-선 회절분석을 통해 얻어진 자료를 이용하여 리트벨트 구조분석을 실시하고 치환된 희토류원소의 거동을 단결정법으로 구해진 결과와 비교.분석하였다. 리트벨트 구조분석결과 합성불화인회석은 공간군 $P6_3$/m, 단위포는 평균하여 a=9.3906(1) $\AA$, c=6.8924(1) $\AA$, V=527.36 $\AA^3$의 값을 갖는다. 구조의 정밀도를 나타내는 R 지수를 보면 $R_{B}$ / 값은 17.29~18.80이고 S(GofF)값은 1.44~1.68로 계산되었다. 불화인회석은 9개의 산소를 배위하는 Ca1자리와 6개의 산소와 하나의 불소가 배위하는 Ca2자리가 있으며 Ca1-O의 평균거리는 2.563 $\AA$이고 Ca2-O의 평균거리는 $2.460 \AA$으로 Ca1자리가 Ca2자리보다 다소 크다. 구조자리 치환식에서는 $Ca^{2+}$ / 자리를 치환하는 $REE^{3+ }$ 로 인하여 전하균형을 맞춰주기 위해서 인과규소가 함께 참여하였다. ($REE^{3}$+Si$^{ 4+}$ $2Ca^{2+}$ : Ca1) 계산된 희토류원소의 자리점유율(REE-Ca2/REE-Cal)은 원자번호가 증가함에 따라 일정하게 감소하는 경향을 보여주며 이는 희토류원소의 거동이 LREE는 크기가 상대적으로 작은 Ca2 자리에 우선 치환되고 HREE는 크기가 큰 Ca1자리에 우선 치환되는 경향을 지시한다.