• Journal of the Korean Society for Heat Treatment
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• v.26 no.3
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• pp.113-119
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• 2013

Grain growth behaviors of hot-rolled AZ31 (Mg-3%Al-1%Zn) and AZ31-0.3%CaO alloys at elevated temperatures have been investigated in order to clarify the effect of CaO addition on grain stability of Mg-Al-based wrought alloy. The grain size of CaO-free alloy increased steeply from 673 K with an increase in annealing temperature from 573 to 773 K, whereas the grains of CaO-containing alloy were relatively stable up to 723 K. The activation energies for grain growth ($E_g$) were 12.2 and 18.3 kJ/mole between 573 and 673 K and 119.2 and 126.9 kJ/mole between 673 and 773 K in the AZ31 and AZ31-0.3%CaO alloys, respectively. This result indicates that grains in the CaO-added alloy possess higher thermal stability than CaO-free alloy. SEM observations on the annealed alloy samples revealed that higher grain stability resulting from CaO addition would be associated with the suppression of grain growth by Ca-related precipitate particles distributed in the microstructure.

• Development and Reproduction
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• v.15 no.1
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• pp.31-39
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• 2011

Change in intracellular $Ca^{2+}$-concentration ($[Ca^{2+}]_i$) is an essential event for egg activation and further development. $Ca^{2+}$ ion is originated from intracellular $Ca^{2+}$-store via inositol 1,4,5-triphosphate receptor and/or $Ca^{2+}$ influx via $Ca^{2+}$ channel. This study was performed to investigate whether changes in $Ca^{2+}$/calmodulin dependent protein kinase II (CaM KII) activity affect $Ca^{2+}$ influx during artificial egg activation with ethanol using $Ca^{2+}$ monitoring system and whole-cell patch clamp technique. Under $Ca^{2+}$ ion-omitted condition, $Ca^{2+}$-oscillation was stopped within 30 min post microinjection of porcine sperm factor, and ethanol-induced $Ca^{2+}$ increase was reduced. To investigate the role of CaM KII known as an integrator of $Ca^{2+}$- oscillation during mammalian egg fertilization, CaM KII activity was tested with a specific inhibitor KN-93. In the eggs treated with KN-93, ethanol failed to induce egg activation. In addition, KN-93 inhibited inward $Ca^{2+}$ current ($I_{Ca}$) in a time-dependent manner in whole-cell configuration. Immunostaining data showed that the voltage-dependent $Ca^{2+}$ channels were distributed along the plasma membrane of mouse egg and 2-cell embryo. From these results, we suggest that $Ca^{2+}$ influx during fertilization might be controlled by CaM KII activity.

• Journal of Korea Foundry Society
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• v.27 no.3
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• pp.126-130
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• 2007

Oxidation behavior of CaO added Mg and Mg-5Al alloys was investigated. At $500^{\circ}C$, oxidation rate of pure Mg was abruptly increased, while that of CaO added Mg was remarkably reduced with increasing CaO content. As a result of surface analysis by AES, there was the thin oxide layer mixed with MgO and CaO in CaO added Mg. Oxidation behavior of CaO added Mg was similar to that of Ca added Mg. Oxidation rate of 0.6CaO added Mg-5Al alloy was much lower than that of Mg-5Al alloy at $500^{\circ}C$ and both alloys showed the linear weight change at $400^{\circ}C$.

• Preventive Nutrition and Food Science
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• v.9 no.1
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• pp.45-52
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• 2004

Effects of dietary calcium lactate (CaL-A) and Chungkukjang (Korean native fermented soybean) on bone mass, calcium status, body weight, serum glucose and cholesterol levels in young male rats were investigated. Chungkukjang was fermented by mixing 4 types of Bacillus sp., and then dried at 45$^{\circ}C$. Calcium lactate was prepared from the ash of black snail. The rats were fed a commercial rat diet for 1 week and then the experimental diets for 4 weeks. Animals were divided into four dietary groups: one calcium-deficient diet (Ca-De) and one of three with calcium supplemented diets (5 g calcium/kg diet) with either calcium phosphate (Ca-P), CaL-A, or CaL-A + Chuntkukjang (CaL-AC). Calcium supplemented diets contained 39 g Ca-P/kg diet and 28 g/kg of calcium lactate in the CaL-A and CaL-AC diets. Body weight gains during the 4 weeks in the Ca-P, CaL-A, CaL-AC and Ca-De groups were 130.45 g,112.50 g, 143.40 g and 10.20 g, respectively. Feed consumption of the groups from high to low was CaL-AC > Ca-P > CaL-A > Ca-De. The Ca-De group had low femur weights and low serum calcium concentrations, while they were comparatively high in CaL-AC, Ca-P and CaL-A groups. The Ca-De groups excreted less calcium in urine than did the other rats, probably due to increased absorption of the mineral in Ca-P, CaL-A and CaL-AC groups. Microscopic observations revealed that there were many regularly spaced holes in the femur of Ca-De group, while there were much smaller regularly spaced holes in Ca-P group. However, no holes in femur were observed in the CaL-A and CaL-AC groups. Bone surfaces were especially smooth and clean in the CaL-AC group. Serum concentrations of glucose and total cholesterol were remarkably lower in the CaL-AC group than in the other supplemented groups. These results suggest that calcium from CaL-A has higher bioavailability than from Ca-P, and dietary Chungkukjang may have a beneficial effect on calcium metabolism.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.15
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• pp.6295-6300
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• 2014

Our aim was to investigate the value of combined detection of serum carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 19-9, CA 242 and CA 50 in diagnosis and assessment of prognosis in consecutive gastric cancer patients. Clinical data including preoperative serum CEA, CA 19-9, CA 242, and CA 50 values and information on clinical pathological factors were collected and analyzed retrospectively. Univariate and multivariate survival analyses were used to explore the relationship between tumor markers and survival. Positive rates of tumor markers CEA, CA 19-9, CA 242 and CA 50 in the diagnosis of gastric cancer were 17.7, 17.1, 20.4 and 13.8%, respectively, and the positive rate for all four markers combined was 36.6%. Patients with elevated preoperative serum concentrations of CEA, CA 19-9, CA 242 and CA 50, had late clinical tumor stage and significantly poorer overall survival. Five-year survival rates in patients with elevated CEA, CA 19-9, CA 242 and CA 50 were 28.1, 25.8, 27.0 and 24.1%, respectively, compared with 55.0, 55.4, 56.4 and 54.5% in patients with these markers at normal levels (p<0.01). In multivariate Cox proportional hazards analyses, an elevated CA 242 level was determined to be an independent prognostic marker in gastric cancer patients. Combined detection of four tumor markers increased the positive rate for gastric cancer diagnosis. CA 242 showed higher diagnostic value and CA 50 showed lower diagnostic value. In resectable gastric carcinoma, preoperative CA 242 level was associated with disease stage, and was found to be a significant independent prognostic marker in gastric cancer patients.

• Korean Journal of Environmental Agriculture
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• v.27 no.3
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• pp.253-259
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• 2008

Soil environmental conditions can affect nutrient availability during growth stage of tree fruit. We investigated the cause of disorderd fruit by the influence of soil chemical properties in orchard soil, composition of mineral nutrient in leaves and fruit to occur physiological disorderd fruit at four locations (Ulsan, Gyeongju, Pyeongtaek, Ansung) compared to healthy. There were significantly different (P=0.05) in exchangeable Ca, K, Mg and total nitrogen content in orchard soil between physiological disordered fruit and healthy fruit. The exchangeable Ca content in orchard soil caused by physiological disordered fruit was statistically lower than that of healthy fruit. However, exchangeable K, Mg and total nitrogen contents were higher than that healthy (P=0.05). There was a significant difference (P=0.05) in Ca content between physiological disordered fruit and healthy. Ca content in fruit flesh of physiological disorderedfruit was statistically lower than that of healthy. The physiological disordered fruit was a higher ratio of Mg/Ca in fruit flesh and peel compared to healthy fruit and also the ratios of N/Ca and K/Ca in a leaf were higher. The negative correlation between Ca and K, and Ca and Mg was detected in the fruit flesh of physiological disordered fruit. Therefore, we concluded that insufficient Ca content in fruit may cause 'the physiological disorder' pomelo disease and high content of N, exchangeable K and Mg ion in the soil solution might be disturbs exchangeable Ca ion to be absorbed in fruit.

• The Korean Journal of Pharmacology
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• v.18 no.2
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• pp.89-102
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• 1982

The $Na^+-and\;K^+-induced\;Ca^{++}$ release was measured isotopically by millipore filter technique in pig heart mitochondria. With EGTA-quenching technique, the characteristics of mitochondrial $Ca^{++}-pool$ and the sources of $Ca^{++}$ released from mitochondria by $Na^+\;or\;K^+$ were analyzed. The mitochondrial $Ca^{++}-pool$ could be distinctly divided into two components: internal and external ones which were represented either by uptake through inner membrane, or by energy independent passive binding to external surface of mitochondria, respectively. In energized mitochondria, a large portion of $Ca^{++}$was transported into internal pool with little external binding, while in de-enerigzed state, a large portion of transported $Ca^{++}$ existed in the external pool with limited amount of $Ca^{++}$ in the internal pool which was possibly transported through the $Ca^{++}-carrier$ present in the inner membrane. $Na^+$ induced the $Ca^{++}$ release from both internal pool and external pool and external binding pool of mitochondria. In contrast, $K^+$ did not affect $Ca^{++}$ of the internal pool, but, displaced $Ca^{++}$ bound to external surface of the mitochondria. When the $Ca^{++}-reuptake$ was blocked by EGTA, the $Ca^{++}$ release from the internal pool by $Na^+$ was rapid; the rate of $Ca^{++}-efflux$ appeared to be a function of $[Na^+]^2$ and about 8mM $Na^+$ was required to elicit half-maximal velocity of $Ca^{++}-efflux$. So it was revealed that $Ca^{++}-efflux$ velocity was particulary sensitive to small changes of the $Na^+$ concentration in physiological range. Energy independent $Ca^{++}-binding$ sites of mitochondrial external surface showed unique characteristics. The total number of external $Ca^{++}-binding$ sites of pig heart mitochondria was 29 nmoles per mg protein and the dissociation constant(Kd) was $34{\mu}M$. The $Ca^{++}-binding$ to the external sites seemed to be competitively inhibited by $Na^+\;and\;K^+$; the inhibition constant(Ki) were 9.7 mM and 7.1 mM respectively. Considering the intracellular ion concentrations and large proportion of $Ca^{++}$ uptake in energized mitochondria, the external $Ca^{++}-binding$ pool of the mitochondria did not seem to play a significant role on the regulation of intracellular free $Ca^{++}$ concentration. From this experiment, it was suggested that a small change of intracellular free $Na^+$ concentration might play a role on regulation of free $Ca^{++}$ concentration in cardiac cell by influencing $Ca^{++}-efflux$ from the internal pool of mitochondria.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.264-267
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• 2008

Many researchers have studied synthesis method of 90/150 group CA. However, there is a lack of researches for synthesis method of 90/150 nongroup CA. In this paper we report some interesting properties of 90/150 multiple-attractor CA in which all of the cycles are of unit length. 90/150 multiple-attractor CA is a class of nongroup CA. And we propose a construction of 90/150 single-attractor CA. Also we construct 90/150 multiple-attractor CA derived from 90/150 single-attractor CA.

• BMB Reports
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• v.44 no.10
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• pp.635-646
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• 2011

Due to its high external and low internal concentration the $Ca^{2+}$ ion is used ubiquitously as an intracellular signaling molecule, and a great many $Ca^{2+}$-sensing proteins have evolved to receive and propagate $Ca^{2+}$ signals. Among them are ion channel proteins, whose $Ca^{2+}$ sensitivity allows internal $Ca^{2+}$ to influence the electrical activity of cell membranes and to feedback-inhibit further $Ca^{2+}$ entry into the cytoplasm. In this review I will describe what is understood about the $Ca^{2+}$ sensing mechanisms of the three best studied classes of $Ca^{2+}$-sensitive ion channels: Large-conductance $Ca^{2+}$-activated $K^+$ channels, small-conductance $Ca^{2+}$-activated $K^+$ channels, and voltage-gated $Ca^{2+}$ channels. Great strides in mechanistic understanding have be made for each of these channel types in just the past few years.

• Archives of Pharmacal Research
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• v.12 no.2
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• pp.128-134
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• 1989

$Na^+-Ca^{2+}$ exchange process in sarcolemmal vesicles isolated from mesenteric arteries of Wistar-Kyoto normotensive(WKY) and spontaneously hypertensive rats(SHR) was investigated. The sarcolemmal fractions isolated after homogenization and sucrose density gradient centrifugation were enriched with 5'-nucleotidase and ouabain sensitive, $K^+-dependent$ phosphatase activities. When the vesicles were loaded with $Na^+$, a time dependent $Ca^{2+}$ uptake was observed. However, very little $Ca^{2+}$ uptake was observed when the vesicles were loaded with $K^+$, or $Ca^{2+}$ uptake of the $Na^+-loaded$ vesicles was carried out in high sodium medium so that there was no sodium gradient. When the vesicles loaded with $Ca^{2+}$ by $Na^+-Ca^{2+}$ exchange were diluted into potassium medium containing EGTA, $Ca^{2+}$ was rapidly released from the vesicles. $Na^+-dependent\;Ca^{2+}$ uptake was increased in SHR compared to WKY, but passive efflux of preaccumulated $Ca^{2+}$ from the vesicles was decreased in SHR. The data indicate that the membrane vesicles of rat mesenteric arteries exhibit $Na^+-Ca^{2+}$ exchange activity. It is also suggested that changes of this process in vascular smooth muscle cell membrane of SHR may be involved in higher intracellular $Ca^{2+}$ concentration and higher basal tone in SHR.