• Advances in concrete construction
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• v.12 no.6
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• pp.479-490
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• 2021

Present research is mainly focused on, microstructural and durability analysis of Graphene Oxide (GO) in Wollastonite (WO) induced cement mortar with silica fume. The study was conducted by evaluating the mechanical properties (compressive and flexural strength), durability properties (water absorption, sorptivity and sulphate resistance) and microstructural analysis by SEM. Cement mortar mix prepared by replacing 10% ordinary portland cement with SF was considered as the control mix. Wollastonite replacement level varied from 0 to 20% by weight of cement. The optimum replacement of wollastonite was found to be 15% and this was followed by four sets of mortar specimens with varying substitution levels of cementitious material with GO at dosage rates of 0.1%, 0.2%, 0.3% and 0.4% by weight. The results indicated that the addition of up to 15%WO and 0.3% GO improves the hydration process and increase the compressive strength and flexural strength of the mortar due to the pore volume reduction, thereby strengthening the mortar mix. The resistance to water penetration and sulphate attack of mortar mixes were generally improved with the dosage of GO in presence of 15% Wollastonite and 10% silica fume content in the mortar mix. Furthermore, FE-SEM test results showed that the WO influences the lattice framework of the cement hydration products increasing the bonding between silica fume particles and cement. The optimum mix containing 0.3% GO with 15% WO replacement exhibited extensive C-S-H formation along with a uniform densified structure indicating that calcium meta-silicate has filled the pores.

• Analytical Science and Technology
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• v.22 no.1
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• pp.92-100
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• 2009

Azacrown resins were synthesized by mixing 1-aza-12-crown-4 macrocyclic ligand into styrene (2th petroleum in 4th class hazardous materials) divinylbenzene (DVB) copolymer with crosslinkage of 1%, 2%, 5% and 10% by substitution reaction. The synthesis of these resins was confirmed by content of chlorine, element analysis, thermogravimetric analysis (TGA), surface area (BET), and IR-spectroscopy. The effects of pH, time, crosslinkage of resins and dielectric constant of solvent on adsorption of metal ions by resin adsorbent were investigated. Metal ions showed a great adsorption over pH 3 and adsorption equilibrium of metal ions was about two hours. In addition, adsorptive selectivity of metals on the resin in ethanol solvent was increased in the order of ${UO_2}^{2+}$ > $Ca^{2+}$ > $Sm^{3+}$ ion and adsorption of uranium ion was decreased with increase of crosslinkage such as 1%, 2%, 5% and 10% and was inversely proportional to the order of dielectric constant of solvents.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.560-567
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• 2023

This study is part of the research on fire-resistant materials to prepare for changing fire behavior, oyster shell and egg shell, which are natural calcium carbonate materials, were substituted as fine aggregates. The purpose of this study was to evaluate the strength and fire resistance performance according to the substitution rate, and to provide data for use as fire resistance material. Oyster shells and egg shells were substituted with 10~50 % of the fine aggregate, respectively, and tested for strength and Simplified heating according to the KS test method. Although the strength of OS was measured to be higher than that of ES, the backside temperature was also measured to be higher. As a result, it is recommended to use fireproof boards with OS where strength performance is required, such as explosive fires, Where high fire resistance performance is required, such as high-temperature fires over 1000 ℃, fireproof boards with ES can be selected according to the application.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.1
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• pp.33-39
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• 2024

This study explores the utilization of common marine wastes, specifically seashells, such as oysters and cockles, as alternative fine aggregates in construction materials. The considered seashells were cleaned and pre-processed for use as a substitute for aggregate in mortar. Cement mortar specimens were prepared under different conditions, such as substitution ratios and the cleaning status of the seashells. The compressive strength of the mortars specimens was evaluated, and the solid and porous structures of each specimen were analyzed using microstructure analysis methods such as XRD, SEM, and micro-CT. The results confirmed that oyster and cockle seashells are composed of different calcium carbonate polymorphs, and their microstructural characteristics influence the mechanical properties of the cement mortar specimens.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.422-430
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• 2023

The nutrient-rich and climate-resilient finger millet (Eleusine coracana (L.) Gaertn.) is a relatively new crop on the agricultural landscape. The present study explores the agronomic characteristics and antioxidant activities of grains and cookies produced from 'Finger1ho,' which was the first finger millet variety developed in South Korea. With heightened calcium content (314 mg/100 g) and polyphenol levels, 'Finger1ho' exhibited superior radical scavenging activities compared to other millets. The investigation assessed the impact of whole finger millet flour at varying concentrations (0, 10, 30, 50, and 100%) on cookie properties. Increasing the substitution of finger millet flour in the cookie formulation resulted in a notable rise in calcium content, ranging from 1.8 times at 10% to an impressive 10.8 times at 100%, surpassing the levels found in conventional wheat cookies. Conversely, the sodium (Na) levels in finger millet cookies demonstrated minimal variations, presenting a potentially favorable aspect in addressing the high Na intake prevalent in the South Korean diet. Notably, the antioxidant activity, assessed through ABTS and DPPH radical scavenging assays, exhibited a significant elevation compared to the control. This increase in antioxidant activity was directly proportional to the quantity of finger millet incorporated (p<0.001), indicating the potential health benefits associated with higher levels of finger millet in the cookie formulation. This study highlights finger millet's potential as a beneficial ingredient, enhancing both consumer acceptability and the functional attributes of cookies. Notably, cookies with 10% to 50% added finger millet exhibited significantly superior quality characteristics compared to controls, suggesting promising avenues for health-functional cookie development.

• Journal of the Mineralogical Society of Korea
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• v.16 no.1
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• pp.75-90
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• 2003

Ettringite and thaumasite were observed in some concrete. The morphology and occurrence of these minerals were closely examined by performing SEM/EDAX analyses. We also experimentally induced the concrete deterioration using $Na_2SO_4$ solution with application of various environmental conditions. The stability of these minerals and deterioration characteristics under applied experimental conditions were determined. Abundant ettringite formed by“through solution reaction”occurred in many open spaces, and some microscopic ettringite formed by "tophochemical replacement" of calcium aluminate also occurred in cement paste. Severe cracking of cement paste causing premature deterioration was often associated with ettringite location. Under specific condition, ettringite was transformed to thaumasite, tricthloroaluminate, or decomposed. Thaumasite occurred with association of ettrinsite in concrete containing carbonate aggregate being subject to dedolomitization or in some concrete being subject to carbonation. Thaumasite appears to be formed under the similar condition to the general ettringite forming condition, but it formed solid solution with ettringite by substituting pre-existing ettringite. Ettringite can also be transformed to trichloroaluminate in the presence of abundant chlorides, but trichloroaluminate changed back to ettringite in late sulfate attack. It is considered that the substitution reaction direction solely depend on the concentration of chloride and sulfate ion.

• Clinical and Experimental Pediatrics
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• v.51 no.7
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• pp.771-774
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• 2008

Familial hypokalemic periodic paralysis (hypoPP) is a rare inherited channelopathy that often presents with episodic weakness accompanied by hypokalemia. Thus far, mutations in the gene encoding two ion channels (CACNL1A3, L-type calcium channel alpha-1 subunit and SCN4A, a sodium channel type IV alpha subunit) have been identified. Several cases of familial hypoPP in children have been reported in Koreans, but there are only a few cases with identified mutations. We report a 12-year-old boy and his affected mother with hypoPP who has a heterozygous G to A substitution at codon 1239 in exon 30 of the CACNL1A3 gene that causes a change from arginine to histidine (Arg1239His, CACNL1A3). This mutation is common among Caucasians; however, it has not yet been reported in Koreans. The patients were treated with oral acetazolamide and potassium replacement and were instructed to avoid precipitating factors. After the medication and lifestyle modification, the paralytic attacks significantly decreased.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.1
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• pp.34-41
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• 2017

Anticonvulsants, calcium channel blockers and immunosuppressants are representative drugs related with gingival enlargement. Clinical signs and symptoms caused by drug-induced gingival enlargment frequently appear within 1 to 3 months after medication. At initial stage, it is limited to attached gingiva but may extend coronally and interfere with esthetics, mastication and speech. Interproximal spaces are common beginning area and pathologic teeth migration could be occurred by the lesion. Withdrawal or substitution of medication would be the most effective treatment of drug-induced gingival enlargement. However, periodontal treatment and further supportive periodontal therapy should be provided where change in medication is impossible. The present study reports the cases which show the resolution of inflammation with spontaneous teeth migration without change in medication. In all cases discussed in this report could be efficiently managed with proper periodontal treatment and further supportive periodontal therapy.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7337-7341
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• 2014

Background: The physiological role of vitamin D extends beyond bone health and calcium-phosphate homeostasis to effects on cancer risk, mainly for colorectal cancer. Vitamin D may have an anticancer effect in colorectal cancer mediated by binding of the active form $1,25(OH)_2D$ to the vitamin D receptor (VDR). The Taq1 VDR gene polymorphism, a C-to-T base substitution (rs731236) in exon 9 may influence its expression and function. The aim of this study wass to determine the 25(OH)D vitamin D level and to investigate the association between circulating vitamin D level and Taq1VDR gene polymorphism among Jordanian colorectal cancer patients. Materials and Methods: This case control study enrolled ninety-three patients and one hundred and two healthy Jordanian volunteers from AL-Basheer Hospital/Amman (2012-2013). Ethical approval and signed consent forms were obtained from all participants before sample collection. 25(OH)D levels were determined by competitive immunoassay Elecsys (Roche Diagnostic, France). DNA was extracted (Promega, USA) and amplified by PCR followed by VDR Taq1 restriction enzyme digestion. The genotype distribution was evaluated by paired t-test and chi-square. Comparison between vitamin D levels among CRC and control were assessed by odds ratio with 95% confidence interval. Results: The vitamin D serum level was significantly lower among colorectal cancer patients (8.34 ng/ml) compared to the healthy control group (21.02ng/ml). Patients deficient in vitamin D (less than 10.0 ng/ml) had increased colorectal cancer risk 19.2 fold compared to control. Only 2.2% of CRC patients had optimal vitamin D compared to 23.5% among healthy control. TT, Tt and tt Taq1 genotype frequencies among CRC cases was 35.5%, 50.5% and 14% compared to 43.1%, 41.2% and 15.7% among healthy control; respectively. CRC patients had lower mean vitamin D level among TT ($8.91{\pm}4.31$) and Tt ($9.15{\pm}5.25$) genotypes compared to control ($21.3{\pm}8.31$) and ($19.3{\pm}7.68$); respectively. Conclusions: There is significant association between low 25(OH)D serum level and colorectal cancer risk. The VDRTaq1 polymorphism was associated with increased colorectal cancer risk among patient with VDRTaq1 TT and Tt genotypes. Understanding the functional mechanism of VDRTaq1 TT and Tt may provide a strategy for colorectal cancer prevention and treatment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.1
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• pp.97-102
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• 2008

For the use of salmon frame in zero emission, the snack using residues of salmon Gomtang was prepared and investigated on the food component characterization. According to the results of volatile basic nitrogen, water activity and sensory evaluation, the optimal substitution ratio of residues was 15% based on the mix. Total amino acid content was higher in the snack (14.8 g/100 g) with 15% residues than in snack (9.8 g/100 g) without residues. The major amino acids of the residues-added snack were aspartic acid (9.9%), glutamic acid (14.7%) and proline (9.5%). The snack with 15% residues were enriched in the mineral (calcium and phosphorus) and polyunsaturated fatty acid (20:5n-3 and 22:6n-3) compared to those of snack without residues.