• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
• /
• pp.237-239
• /
• 1993

$MnO_2$ added $(Pb_{0.45}Ca_{0.55})(Fe_{0.5}Nb_{0.5})O_3$ was calcined at $850^{\circ}C$ for two hours and sintered at $1100^{\circ}C$ for two hours. The microstructure was examined using XRD and SEM. The dielectric constant, the quality factor, and the temperature stability was measured using Hakki and Coleman method. Dielectric constant was improved to 94 from 0.5wt% $MnO_2$ added sample with $Q{\cdot}f=4260GHz$ and acceptable ${\tau}_f$ (< $20ppm/^{\circ}C$).

• The Korean Journal of Physiology
• /
• 제28권2호
• /
• pp.169-179
• /
• 1994

The effect of extracellular and intracellular pH on vascular tone and $^{45}Ca$ uptake were investigated in aortic strips and dispersed single aortic smooth muscle cells of spontaneously hypertensive rats (SHR) and aged-matched Wistar-Kyoto rats (WKY). The contraction produced by a change of extracellular pH (pHo) in the range of $6.5{\sim}8.3$ was estimated by comparison with the level of vascular tone at pH 7.4. Contraction was induced below pHo 6.5 in WKY, pHo 7.1 in SHR, and over pHo 8.0 on both strains. The amplitude of contraction induced by high pHo (over pHo 7.7) was similar in SHR and WKY, but that induced by low pHo (below pHo 7.1) in SHR was greater than that in WKY. Either high pHo- or low pHo-induced contractions in WKY and SHR were not induced in the Ca-free Tyrode's solution and were induced by the addition of Ca. $^{45}Ca$ uptake increased progressively as pHo was increased from 6.8 to 8.1 in the single aortic smooth muscle cells of WKY and SHR. $NH_4Cl$ induced a gradually developing contraction in a dose-dependent manner $(5\;mM{\sim}30\;mM)$ and the removal of $NH_4Cl$ induced transient contraction was followed by profound relaxation in the aortic rings of both strains. The contractions induced by $NH_4Cl$ or by the removal of $NH_4Cl$ in SHR were significantly greater than that in WKY. These contractions were not induced in Ca-free Tyrode's solution. $^{45}Ca$ uptake was increased by $NH_4Cl$ (20 mM) and was not changed by the removal of $NH_4Cl$ (20 mM) in the aortic strips of WKY and SHR. As a summary of above results, the vascular tone of SHR was more sensitive to the change pHi and pHo than that of WKY. The contractions induced by change of extracellular or intracellular pH depended on extracellular Ca in the aorta of SHR nnd WKY. However, the Ca uptake was in accord with the changes of contraction but increase in contraction by low pH was not accompanied by an increase in Ca uptake in both strains.

• 대한약리학회지
• /
• 제30권1호
• /
• pp.125-136
• /
• 1994

갑각류 골격근의 SR에서 칼슘유리 channel protein complex의 성격을 규명하기 위해 민물가재 및/또는 바다가재의 SR vesicles을 분리하여 $^{45}Ca$ 유리, $[^3H]ryanodine$결합, 및 immunoblot 실험을 실시하여 다음과 같은 결과를 얻었다. 1.민물가재 SR의 $[^3H]ryanodine$결합 실험에서 민물가재 SR의 maximal binding site및 affinity모두 바다가재에서 보다 낮았으나, high affinity binding site이었다. Extravesicles 칼슘농도를 증가시켰을 때 $[^3H]ryanodine$결합은 약간 증가되었으나, AMP나 AMP와 caffeine을 동시에 첨가하였을 때는 현저히 증가되었다(p<0.05). 이런 증가 현상은 $MgCl_2$나 tetracaine으로 유의성 있게 억제되었으나(p<0.001), ruthenium red에 의해서는 약간 억제되었다. 2.민물가재 SR을 전기영동하였을 때 바다가재의 ryanodine receptor band (HMWBr)와 비슷하나 포유류의 것(HMWBS) 보다는 약간 빠른 mobility를 나타낸다. 3.바다가재 HMWBr에 대한 polyclonal Ab를 이용한 민물가재, 바다가재 및 토끼 골격근의 칼슘유리 channel간의 면역학적 교차반응에서 민물가재와 바다가재의 칼슘유리 channel 간에는 교차반응이 있었으나, 포유류의 것과는 아무런 반응이 없었다. 4.민물가재 SR에서 $^{45}Ca$유리는 extravesicles의 칼슘농도 증가에 따라서 증가되었고, 낮은 외부 칼슘 농도에서 바다가재 보다 빠르게 일어났으나, AMP와 caffeine에 의해 영향을 받지 않았고, $MgCl_2$와 tetracaine으로 약간($3{\sim}8%$) 그리고 고농도의 ruthenium red로 중등도(23%) 억제되었다. 이상의 실험성적으로 갑각류 칼슘유리 channel protein은 포유류의 것과는 기능적으로나 면역학적으로 매우 다른 특징을 가지고 있고, 민물가재와 바다가재 칼슘유리 channel은 서로 유사한 특징을 갖지만, 민물가재의 칼슘유리 channel이 바다가재의 것보다 외부칼슘에 예민한 기능을 갖는 것으로 사료된다.

• 한국식품저장유통학회지
• /
• 제13권1호
• /
• pp.13-17
• /
• 2006

딸기를 $20^{\circ}C$와 $45^{\circ}C$의 $1\%\;CaCl_2$ 용액에 각각 15분간 침지시킨 후, PE film (0.011mm)으로 포장한 군과 포장하지 않은 군으로 나누어 $5^{\circ}C$에 저장하였다. 그리고 $CaCl_2$, 용액에 침지시키지 않고 PE film(0.011mm)으로 포장한 군과 포장하지 않은 군으로 나누어 $5^{\circ}C$에 저장하였다. $45^{\circ}C\;CaCl_2$ 용액에 침지시킨 후 포장한 처리구에서 부패율은 낮고 경도가 높게 나타났다. 또한 비타민 C함량이 높았고 외관이 가장 좋은 것으로 나타났으며 다른 처리군에 비해 pH가 낮고 산도가 높게 나타났다. 그러나 당도는 처리군 간에 유의성이 없었다. 따라서 수확 후 칼슘 처리와 포장의 병행은 딸기의 저장에 효과적인 것으로 사료된다.

• 한국식품영양과학회지
• /
• 제19권2호
• /
• pp.115-120
• /
• 1990

This study was conducted to investigate the relation of softening with the mineral compone-nts during ripening of tomato fruits. The mineral contents of Ca, K, Mg, Zn. Fe Mn and Cu and its existence form respiratory rate and hardness during ripening were evaluated. The respiratory rate of tomato fruits was decreased until 42 days after anthesis and then increased the climacteric maximum was found on 49 days after anthesis then decreased. The hardness of tomato fruits during ripening did not change greatly until 45days after anthesis then decrea-sed markedly. The major mineral components of tomato fruits were K, Ca, and Mg, Zn Fe Mn and Cu were the minor components. The contents of soluble Ca, Ma and K increased markedly and those of bound Ca and Mg decreased markedly after 45days during ripening,. However other components were not changed greatly.

• 약학회지
• /
• 제41권5호
• /
• pp.666-671
• /
• 1997

We studied effects of genistein and tyrphostin, inhibitors of tyrosine kinase, on contractions induced by high $K^+$ and norepinephrine in rat aorta. Genistein $(10^{-6}{\sim}10^{-4}M)$ and tyrphostin ($(10^{-5}{\sim}10^{-4}M)$) inhibited high $K^+$ and norepinephrine-induced sustained contractions, respectively in a concentration-dependent manner. High $K^+$ and norepinephrine caused an increase in $^{45}Ca^{2+}$ uptake while $10^{-4}M$ genistein and tyrphostin inhibited the $K^+$ and norepinephrine-increased $^{45}Ca^{2+}$ uptake, respectively. These results show that inhibitor of tyrosine kinase blocks the voltage-and receptor-operated $Ca^{2+}$ channels in rat aorta, respectively.

• 아시안잔디학회지
• /
• 제13권4호
• /
• pp.191-200
• /
• 1999

The objective of this study was to improve the recycling rate of coal ash fly, industrial waste. This study was conducted to analyze the physico-chemical properties of \"CellCaSi\" and clarify the effects on the growth of Kentucky bluegrass(Poa pratensis L.) and creeping bentgrass(Agrostis paulstris Huds \"Penncross\") and the chemical properties of soil, which was cellular calcium silicate reproduced by coal ash fly. A field assay was carried out in Young-Pyong Golf Course. The results were as follows. 1. The main chemical composition of CellCaSi was $SiO_2$(45~55%) and CaO(25~35), which was 70~90% of total weight. CellCaSi showed pH 8~9. Bulk density of CellCaSi was 0.35~0.45g/㎤. Water content of CellCaSi was 52.5~67.5%. 2. In the applied plots, leaf width, grass density per $1\textrm{cm}^2$, rhizome number and length per plant, and root number per plant of Kentucky bluegrass(Poa pratensis L.) and creeping bentgrass(Agrostis paulstris Huds \"Penncross\") showed increasing tendency compared with the control. The application of CellCaSi increased the growth of turfgrasses. Their visual quality on hardness, grass shoot density per $1\textrm{cm}^2$ and root growth was very good. And, their visual quality on rhizome growth was good. 3. After the application of CellCaSi, pH, CEC, Ex-cation of the applied soil showed increasing tendency with the little range, $SiO_2$content increasing tendency considerably, and organic matter content decreasing tendency compared with the control.ncy compared with the control.

• 고려인삼학회:학술대회논문집
• /
• 고려인삼학회 1980년도 학술대회지
• /
• pp.71-76
• /
• 1980

Aortic strips were prepared from rabbits, and the tensions were maintained by administration of norepinephrine into the incubation chamber. The application of diol or triol induced relaxation of the aortic strip, as indicated by the decreased aortic tension. Triol, in a concentration of $30\;mg\%\;causes\;approximately\;50\%$ of muscle relaxation, whereas a similar degree of relaxation is induced by $50\;mg\%$ of diol. This indicates that both triol and diol cause relaxation of the aorta, but that triol is about $170\%$ more potent than diol. It is well established that blood-vessel smooth-muscle tone is regulated by the available intracellular $Ca^{++}$ concentration, which in turn is profoundly influenced by interaction of the cellular membrane and sarcoplasmic reticulum in the smooth muscle. Thus, any agent which modifies the smooth-muscle tone is expected to interfere with the $Ca^{++}$ binding or uptake of sarcolemma and sarcoplasmic reticulum. In the following experiments sarcoplasmic reticulum and sarcolemma were prepared from the ventricle of rabbit heart, and the active $Ca^{++}$ uptake by these cellular components was measured employing $Ca^{45}$ in the presence of triol and diol. It was found that the active $Ca^{++}$ uptake in the presence of ATP by sarcoplasmic reticulum was inhibited by both triol and diol. Panaxatriol, in a concentration of $80\;mg\;\%,$ inhibited $Ca^{++}$ uptake by $30\%,$ whereas panaxatriol in the same concentration inhibited uptake by $20\%.$ It is clear that triol is a more potent inhibitor of active $Ca^{++}$ transport in sarcoplasmic reticulum than diol. The $Ca^{++}$ binding of the cellular membrane was also studied employing Ca45 and milipore techniques. It was found that triol in a concentration of $80\;mg\;\%,$ decreased $Ca^{++}$ binding by $29\%.$ Diol in the same concentration decreased the binding by $17\%.$ It is clear that both triol and diol inhibit $Ca^{++}$ binding to the cellular membrane, but triol is approximately $180\%$ more potent than diol.

• Journal of Korean Dental Science
• /
• 제10권2호
• /
• pp.45-52
• /
• 2017

Calcium has versatile roles in diverse physiological functions. Among these functions, intracellular $Ca^{2+}$ plays a key role during the secretion of salivary glands. In this review, we introduce the diverse cellular components involved in the saliva secretion and related dynamic intracellular $Ca^{2+}$ signals. Calcium acts as a critical second messenger for channel activation, protein translocation, and volume regulation, which are essential events for achieving the salivary secretion. In the secretory process, $Ca^{2+}$ activates $K^+$ and $Cl^-$ channels to transport water and electrolyte constituting whole saliva. We also focus on the $Ca^{2+}$ signals from intracellular stores with discussion about detailed molecular mechanism underlying the generation of characteristic $Ca^{2+}$ patterns. In particular, inositol triphosphate signal is a main trigger for inducing $Ca^{2+}$ signals required for the salivary gland functions. The biphasic response of inositol triphosphate receptor and $Ca^{2+}$ pumps generate a self-limiting pattern of $Ca^{2+}$ efflux, resulting in $Ca^{2+}$ oscillations. The regenerative $Ca^{2+}$ oscillations have been detected in salivary gland cells, but the exact mechanism and function of the signals need to be elucidated. In future, we expect that further investigations will be performed toward better understanding of the spatiotemporal role of $Ca^{2+}$ signals in regulating salivary secretion.

• 상하수도학회지
• /
• 제22권5호
• /
• pp.561-569
• /
• 2008

We analyzed contents of cations and anions for the domestic bottled drinking water. Results showed that total cation content was 45.81 mg/L and contained 40% of Ca. The content of cations were decreased in the order of Ca>Si>Na>Mg>K. Total anion content was 12.20 mg/L and contained 90% of ${SO_4}^{2-}$ and $Cl^-$. $F^-$ and $NO_{3-}N$ were a little contained. While Si content was reduced 2.3~75.7%(mean value:38.5%) after freezing, Ca content was reduced 45.2% after boiling. It showed that water containing higher Ca content was significantly decreased after boiling. Precipitates formed by freezing and boiling is composed of minerals such as Si and Ca. Compared to minerals from food intake, concentrations of minerals from water intake are expected to be less influenced. It is recommended Bottled Water that contains more than 20 mg/L of Ca(exceeding water-quality standard for turbidity) is safe to drink without thawing and boiling.