• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.3
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• pp.291-298
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• 1995

Abstract The growth and dissolution behaviour of reaction phase was studied during dissolution reaction between sintered alumina and $CaMgSiO_4$ at $1600^{\circ}C$ for various times. The formation of $CaO{\cdot}6Al_2O_3$ an intermediate reaction phase, and $CaMgSiO_4$ spinel, the final reaction product were observed during dissolution reaction of alumina into $CaMgSiO_4$ liquid phase. The growth and dissolution shape of $CaO{\cdot}6Al_2O_3$, an intermediate phase, was quite different.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.6
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• pp.597-603
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• 1999

Caldesmon (CaD), one of microfilament-associated proteins, plays a key role in microfilament assembly in mitosis. We have investigated the effects of overexpression of the high molecular weight isoform of CaD (h-CaD) on the physiology of vascular smooth muscle cells (VSMCs). Rat aortic VSMCs were stably transfected with plasmids carrying a full length human h-CaD cDNA under control of cytomegalovirus promoter. The majority of the overexpressed h-CaD appears to be localized predominantly on cytoskeleton structures as determined by detergent lysis. The overexpression of h-CaD, however, does not decrease the level of endogenous low molecular weight isoform of CaD. h-CaD overexpressing VSMCs (h-CaD/VSMCs) show a decreased growth rate than that of vector-only transfected cells when determined by $[^3H]thymidine$ uptake and cell counting after fetal bovine serum (FBS) stimulation. h-CaD/VSMCs were smaller than vector-transfected cells by 18% in cell diameter. These data suggest that overexpression of h-CaD can inhibit the poliferation and the cell volume of VSMCs stimulated by growth factors and that the gene therapy with h-CaD may be helpful to prevent the conditions associated with hypertrophy and/or hyperplasia of VSMCs after arterial injuries.

• 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.

• Journal of Nutrition and Health
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• v.29 no.9
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• pp.943-949
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• 1996

Bone mineral density depends largely on the status of dietary minerals such as Ca, P, Mg, and F and proteins, physical activities, parathyroid hormone(PTH), calcitonin(CT), and vitamin D. The decrease of bone density often results in bone fractures and osteoporosis which is prevalent among postmenopausal women. This study was intended to examine the role of parathyroid hormone, calcitonin and cholecaliferol in bone density of mice that were fed different dual photon energy beams. We have measured three major parts of the bone : whole body, head and femur. The results are summarized as follows : 1) Bone mineral density (BMD) was more increased by feeding high Ca diet compared to that of the low Ca diet. 2) Both PTH and Vit D3 enhanced BMD in all of the different Ca levels. 3) When the dietary Ca was deequate CT showed a synergistic effect with PTH in boosting bone density, while CT+Vit D3 showed a negative effect. 4) CT tended to inhibit the effect of increasing bone density by PTH and Vit D3 in medium and low Ca groups. 5) The effect of increasing bone density by PTH in the head of mouse increased when dietary Ca was lower : The increment of bone density by PTH in high, medium, and low Ca was 3%, 8%, 19%, respectively. 6) Femur bone density was affected significantly by dietary Ca levels than hormones. The above observations indicate that bone mineral density can be improved by high dietary Ca and hormone injections including PTH, CT and cholecalciferol, and thus proper dietary and hormonal treatment may be used in preventing bone fractures and osteoporosis.

• Journal of the Korean Ceramic Society
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• v.23 no.3
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• pp.27-34
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• 1986

The hydration of flyash-$Ca(OH)_2-CaSO_4$.$2H_2O$ system was stuedied with varing mixing ratio of flyahs $Ca(OH)_2$ and caSO4.2H2O The samples were steam-cured for 1-7 days at 9$0^{\circ}C$. The optimum mixing composition was flyash : Ca (OH)2=65:35 with 15% $CaSO_4$.42H_2O$ added which produced the hardened material having the best compressive strength (300kg/$cm^2$) Also the low specific gravity(1, 2) of the hardened paste suggests the possibility that it can be used as a light-weight building material. The added $CaSO_4$.42H_2O$ constituted calcium-sulfo-aluminate hydrates which activates the formation of C-S-H hy-drates. Both hydrates developed the strength of hardened paste. The amount of calcium-sulfo-aluminate hydrates was increased when the $CaSO_4$.42H_2O$ was added over 15% however the increased amount did not help the development of strength because of the individually grown calcium-sulfo-aluminate hydrates.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.2 no.2
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• pp.63-70
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• 1992

$AI_2O_3/Ca-TZP$ composites was prepared by using the starting powder of alumina and Ca-TZP synthesized by hydrothermal reaction and investigated to its characteristics. The ratio of tetragonal zirconia to monoclinic within $AI_2O_3$ matrix was decreased with an addition of Ca-TZP content, but the absolute amount of tetragonal phase in composites was increased with an addition of Ca-TZP content. The value of fracture toughness in $AI_2O_3/Ca-TZP$composites was proportional to the amounts of transformed tetragonal phase which formed by crack propagation in fracture, and therefore, it was gradually increased with an addition of Ca- TZP content.

• Journal of Nutrition and Health
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• v.25 no.2
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• pp.132-139
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• 1992

A study was conducted to compare urinary Ca excretion and factors influencing urinary Ca excretion in 30 young and 62 middle-aged Korean women. Mean daily intake levels of total protein and P were significantly higher in middle-aged women but Ca and animal protein intake levels of the two groups were similar. The average percentage of daily Ca intake from milk and milk products in young women was 45% while in middle-aged women it was about 24% The frequency of milk consumption was inversely correlated with blood pressures of the subjects. Mean 24-hour urinary calcium excretion in young and middle-aged women were 163.7mg and 174.9mg respectively. The difference was not significant. Menopause of the mid-dle-aged women did not affect urinary calcium levels. However the proportion of subjects with more than 250mg of Ca in 24-hour urine tended to be higher in middle-aged group Factors significnatly correlated with urinary Ca excretion of subjects were systolic and diastolic The study verifies the need for more systematic studies on Ca requirements and the interrelation-ship among Ca and na metabolism blood pressures and bone loss in the middle-aged Korean.

• Journal of Microbiology and Biotechnology
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• v.32 no.7
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• pp.949-954
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• 2022

The lipolytic yeast Candida aaseri SH14 contains three Acyl-CoA oxidases (ACOXs) which are encoded by the CaAOX2, CaAOX4, and CaAOX5 genes and catalyze the first reaction in the β-oxidation of fatty acids. Here, the respective functions of the three CaAOX isozymes were studied by growth analysis of mutant strains constructed by a combination of three CaAOX mutations in minimal medium containing fatty acid as the sole carbon source. Substrate specificity of the CaAOX isozymes was analyzed using recombinant C. aaseri SH14 strains overexpressing the respective genes. CaAOX2 isozyme showed substrate specificity toward short- and medium-chain fatty acids (C6-C12), while CaAOX5 isozyme preferred long-chain fatty acid longer than C12. CaAOX4 isozyme revealed a preference for a broad substrate spectrum from C6-C16. Although the substrate specificity of CaAOX2 and CaAOX5 covers medium- and long-chain fatty acids, these two isozymes were insufficient for complete β-oxidation of long-chain fatty acids, and therefore CaAOX4 was indispensable.

• Clinical and Experimental Pediatrics
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• v.49 no.12
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• pp.1340-1347
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• 2006

Purpose : The aim of the present study was to investigate the role of polymorphic cytosine adenine (CA) repeat of the IGF-I gene in the age-related alterations of serum IGF-I levels in healthy children. Methods : Two hundred and forty three normal healthy children (136 boys; 107 girls) aged between 7 and 15 years were enrolled in the present study. The primers were designed to cover the promoter regions containing the polymorphic CA repeat. Data were analyzed using GeneMapper software, version 3.7. All analyses were performed using MEDCALC software packages. Results: Deletion of 2 bp (G, A) following 3' of CA repeat were observed in all Korean children. The CA repeat sequences ranged from 17 to 23, and 19 CA repeat were the most common with an alleles frequency of 39.3 percent. Considering genotypes, 63.8 percent of subjects were homozygote or heterozygote for 19 CA repeat (192 bp allele), suggesting that this is wild type allele from which all other alleles originated in Korean children. Homozygote for 19 CA repeat were 14.7 percent, heterozygote for 19 CA repeat was 49.1 percent and 19 CA noncarriers totalled 36.2 percent. In 19 CA repeat noncarriers, the mean height, weight and serum IGF-I level were lower compared with those of 19 CA homozygous carriers, but statistically not significant. Correlations between serum IGF-I level and age according to the IGF-I genotypes revealed statistically significant relationships in the all groups, in the 19 CA repeat carrier group and, even in the noncarrier group. Conclusions : There were no significant differences of the mean height, weight and serum IGF-I levels among three different genotype groups. Also, there were no significantly different correlations between 19 CA repeat polymorphisms and serum IGF-I levels, according to genotype. Our results suggest that the IGF-I 19 CA repeat gene polymorphism is not associated with circulating IGF-I levels in healthy children.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.1
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• pp.1-9
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• 2014

Calcium (Ca) and phosphorus (P) are minerals that have important physiological functions in the body. For formulation of diets for pigs, it is necessary to consider an appropriate Ca:P ratio for an adequate absorption and utilization of both minerals. Although both minerals are important, much more research has been conducted on P digestibility than on Ca digestibility. Therefore, this review focuses on aspects that are important for the digestibility of Ca. Only values for apparent total tract digestibility (ATTD) of Ca have been reported in pigs, whereas values for both ATTD and standardized total tract digestibility (STTD) of P in feed ingredients have been reported. To be able to determine STTD values for Ca it is necessary to determine basal endogenous losses of Ca. Although most Ca is absorbed in the small intestine, there are indications that Ca may also be absorbed in the colon under some circumstances, but more research to verify the extent of Ca absorption in different parts of the intestinal tract is needed. Most P in plant ingredients is usually bound to phytate. Therefore, plant ingredients have low digestibility of P due to a lack of phytase secretion by pigs. During the last 2 decades, inclusion of microbial phytase in swine diets has improved P digestibility. However, it has been reported that a high inclusion of Ca reduces the efficacy of microbial phytase. It is possible that formation of insoluble calcium-phytate complexes, or Ca-P complexes, not only may affect the efficacy of phytase, but also the digestibility of P and Ca. Therefore, Ca, P, phytate, and phytase interactions are aspects that need to be considered in Ca digestibility studies.