• Archives of Pharmacal Research
• /
• v.10 no.2
• /
• pp.80-87
• /
• 1987

To get a better insight into the exxistence and the role of a Na-Ca exchange mechanism in smooth muscle, the effect of Na substitution with sucrose on tension development, cellular Ca uptake and $^{45}Ca$ efflux was investigated using isolated cat ileal longitudinal muscle strips. Experimental results were summarized as follows;1) Exposure of the cat ileal longitudinal muscle to Na-free solution induced a contraction, and the magnitude of the contraction increased after incubation of the muscle strips with ouabain ($2{\times10^{-}5}$M) for 1hr. 2) Cellular Ca uptake in Na-free solution increased with an increase in Na content of the Na-loading media, and a linear relationship existed between tissue Na content and cellular Ca uptake for 10 min 3) After tissues were equilibrated in PSS containing $^{45}Ca$ for 2hr, cellular Ca uptake decreased with rising the external Na concentration. 4)Removal of medium Na or inhibition of the Na-K pump decreased the rate of $^{45}Ca$ efflux. These results strongly suggested that Na substitution increases cellular Ca uptake and decreases the rate of $^{45}Ca$ efflux via a Na-Ca exchange mechanism.

• Journal of the Korean Applied Science and Technology
• /
• v.23 no.4
• /
• pp.355-361
• /
• 2006

[1,2,4]-Triazole derivatives were synthesized by 5 steps. Benzimidazole was refluxed with ethyl chloroacetate to give 1H-benzimidazole-acetic acid ethyl ester (1) over 52% yield. Ester (1) was refluxed with hydrazine hydrate in the presence of ethanol to afford 1H-benzimidazole-1-acetic acid, hydrazide (2). 5-Benzoimidazol-1-ylmethyl-4H-[1,2,4]triazole-3-thiol (4) was made via coupling of compound (2) with methyl isothiocyanate, followed by cyclization of 1H-benzimidazole-1-acetic acid, 2-[(methylamino) thioxomethyl]hydrazide (3) on reflux, and finally the target compounds (6a-6v) were synthesized by general substitution reaction. Compounds (6a-6v) were screened for T-type calcium channel blocker using the fluorescence assay by FDSS6000. All compounds (6a-6v) did not show better activities than control compound, mibefradil.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2011.11a
• /
• pp.31-32
• /
• 2011

Granulated slag from metal industries and fly ash from the combustion of coal are industrial by-products that have been widely used as mineral admixtures in normal and high strength concrete. Due to the reaction between calcium hydroxide and fly ash or slag, the hydration of concrete containing fly ash or slag is much more complex compared with that of Portland cement. In this paper, the production of calcium hydroxide in cement hydration and its consumption in the reaction of mineral admixtures is considered in order to develop a numerical model that simulates the hydration of concrete containing fly ash or slag. The heat evolution rates of fly ash- or slag-blended concrete is determined by the contribution of both cement hydration and the reaction of the mineral admixtures. Furthermore, the temperature distribution and temperature history in hardening blended concrete are evaluated based on the degree of hydration of the cement and the mineral admixtures. The proposed model is verified through experimental data on concrete with different water-to-cement ratios and mineral admixture substitution ratios.

• Computers and Concrete
• /
• v.23 no.3
• /
• pp.189-201
• /
• 2019

Recent advances in the concrete technology are aiding in minimizing the use of conventional materials by substituting by-products of various industries and energy sources. A large amount of stone waste i.e., dust and slurry form both are being originated during natural stone processing and causing deadily effects on the environment. The disposal problem of stone waste can be resolved effectively by using waste in construction industries. In present work, Kota stone slurry powder, as a substitution of cement was used along with accelerators namely calcium nitrate and triethanolamine as additives, to study their impact on various properties of the concrete mixtures. Kota stone slurry powder (7.5%), calcium nitrate (1%) and triethanolamine (0.05%) were used separately as well in combination in different concrete mixtures. Mechanical Strength, modulus of elasticity and electrical resistivity of concrete specimens of different mix proportions under water curing were studied experimentally. The durability properties in terms of strength and electrical resistivity against sulphate and chloride solution attack at various curing ages were also studied experimentally. Results showed that accelerators and Kota stone slurry powder separately enhanced the mechanical strength and electrical resistivity; but, their combination decreased strength at all curing ages. The durability of concrete specimens was also affected under the exposure to chemical attack too. Kota stone slurry powder found to be the most effective material among all materials. Material characterization was also done to study the microstructural properties.

• The Korean Journal of Mycology
• /
• v.49 no.1
• /
• pp.109-118
• /
• 2021

In this study, we analyzed the diversity of ectomycorrhizal (ECM) fungal communities of Quercus spp. roots in the limestone area. We identified 45 generd of ECM using next generation sequencing (NGS) analysis. Soil chemical composition analysis confirmed soil pH, substitution calcium concentration, total nitrogen content, organic phosphate, and organic matter content. Shannon's Index was calculated according to the changes in soil chemical composition. The results of cluster analysis showed that Sebacina, Tomentella, Tuber, Densospora, Inocybe, Suillus, and Piloderma were the main genera of symbiotic ECM fungi that thrived in soil with high pH and calcium content.

• Journal of the Korea Institute of Building Construction
• /
• v.24 no.2
• /
• pp.181-191
• /
• 2024

In the realm of cement manufacturing, concerted efforts are underway to mitigate the emission of greenhouse gases. A significant portion, approximately 60%, of these emissions during the cement clinker sintering process is attributed to the decarbonation of limestone, which serves as a fundamental ingredient in cement production. Prompted by these environmental concerns, there is an active pursuit of alternative technologies and admixtures for cement that can substitute for limestone. Concurrently, initiatives are being explored to harness technology within the cement industry for the capture of carbon dioxide from industrial emissions, facilitating its conversion into carbonate minerals via chemical processes. Parallel to these technological advances, economic growth has precipitated a surge in construction activities, culminating in a steady escalation of construction waste, notably waste concrete. This study is anchored in the innovative production of calcium silicate cement clinkers, utilizing finely powdered waste concrete, followed by a thorough analysis of their mineral phases. Through X-ray diffraction(XRD) analysis, it was observed that increasing the substitution level of waste concrete powder and the molar ratio of SiO₂ to (CaO+SiO₂) leads to a decrease in Belite and γ-Belite, whereas minerals associated with carbonation, such as wollastonite and rankinite, exhibited an upsurge. Furthermore, the formation of gehlenite in cement clinkers, especially at higher substitution levels of waste concrete powder and the aforementioned molar ratio, is attributed to a synthetic reaction with Al₂O₃ present in the waste concrete powder. Analysis of free-CaO content revealed a decrement with increasing substitution rate of waste concrete powder and the molar ratio of SiO₂/(CaO+SiO₂). The outcomes of this study substantiate the viability of fabricating calcium silicate cement clinkers employing waste concrete powder.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.14 no.3
• /
• pp.110-114
• /
• 2004

Formation behavior of aragonite precipitated calcium carbonate was investigated with changed the concentration of $Na_2CO_3$ solution and addition method which added in the $Ca(OH)_2$ slurry at $75^{\circ}C$. In this reaction, we found that $Na^+$ ions were substituted into $Ca^{2+}$ion site then disturb the growth of calcite, and while proceed the crystal growth in a certain direction and promote the formation of aragonite. Also, a decrease of reaction rate by control the concentration of $CO_3^{2-}$ ion, induce the homogeneous precipitate reaction and increase substitution ability of $Na^+$ ions, consequently it was promote the formation and growth of aragonite.

• Korean Journal of Food Science and Technology
• /
• v.31 no.5
• /
• pp.1203-1210
• /
• 1999

Soy sauce was fermented with the addition of mountain edible herbs, Ligularia fischeri, Codonopsis lanceolata and Symphytum officinale. In general, the total nitrogen content of soy sauce was increased with the increment of the amount of added mountain herbs. The mineral contents of calcium and potassium in the soy sauce after four months of aging at 20% substitution of Codonopsis lanceolata were increased by 1.3 and 1.5 times, respectively. With 10% substitution of mountain herb mixtures, the contents of tyrosine and arginine were increased by about 2 times as compared to the control. In the Rec assay system, antimutagenic effect of soy sauce with 10 and 20% substitution of Codonopsis lanceolata was higher than other samples. The results of sensory evaluation revealed that overall acceptability of soy sauce with 7% substitution of Codonopsis landeolata and 5% of mountain herb mixture exceeded other groups of samples.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.18 no.1
• /
• pp.113-120
• /
• 1994

The Purpose of this study was to improve the moisture related properties of viscose rayon fibers. Viscose rayon filament yarns were partially etherified to make CMC fibers. CMC fibers were converted to the sodium, calcium, and ferric salt forms by an ion exchange method. The property changes of ion exchanged CMC fibers were examined. Cation contents of fibers were varied depending on the degree of substitution of CMC fibers. The strength of Na, Ca, Fe-CMC was higher than H-CMC owing to the plasticization by moisture sorption and the crosslinking by cations. The moisture regain was increased by carboxymethylation and that of Fe-CMC showed the highest value. The degree of swelling determined by the water retention value was observed to be Na-CMC > Ca-CMC > H-CMC > Fe-CMC. The solution retention value was decreased in the order . Ca-CMC > Na-CMC > H-CMC > Fe-CMC.

• Journal of the Korean Ceramic Society
• /
• v.37 no.5
• /
• pp.410-417
• /
• 2000

In this study the effects of specifics surface area of cement, addition amount of gypsum and substitution ratio of gypsum anhydrite ont he physical properties of cement mortars were investigated by measruements of setting time, flow, compressive strength and hydration heat evolution rate. The results showed that fluidity of mortars was increased by 40 wt.% of maximum flow change with the decreasing specific surface area of cement from 3,500$\textrm{cm}^2$/g to 3,300${\pm}$50$\textrm{cm}^2$/g and affected by the relationship between the cement and balancing between the chemical activityof cement and solubility of calcium sulfate are desirable to prevent the fluidity of concrete from decreasing by high temperature in summer season.