• Food Science of Animal Resources
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• v.33 no.4
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• pp.515-521
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• 2013

In this study, we examined the effects of organic types of calcium derived from oyster shell (OS-Ca) and nano-calcium (Nano-Ca) on the bio-availability and physiological responses associated with bone health in ovariectomised rats. Increased body weight, which is one of the physiological effects of ovary removal, was significantly recovered by Nano-Ca treatment (p<0.05). The reduced calcium level in the liver in ovariectomised rat was increased significantly with OS-Ca and Nano-Ca treatment (p<0.05), suggesting improved calcium bio-availability. Alkaline phosphatase (ALP), osteocalcin, and deoxypyridinoline (DPD) were analysed as biochemical markers of bone metabolism and health in the presence or absence of OSCa and Nano-Ca. ALP, osteocalcin, and DPD levels increased following ovary removal and tended to decrease after treatment with Nano-Ca, indicating that Nano-Ca induces favourable bone metabolism. This result was reflected in the recovery of bone mineral density (BMD) and bone mineral content (BMC) of the femur after Nano-Ca treatment following ovary removal. Taken together, our data show that the tested calcium treatments, especially using Nano-Ca, enhanced the bioavailability or absorption of calcium and positively affected bone metabolism in ovariectomised rats.

• Journal of the Korean Ceramic Society
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• v.44 no.9
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• pp.517-523
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• 2007

For the preparation of tricalciumaluminate $(C_3A)$ clinker, in traditional clinkering method using oxides and carbonates as a raw material, uneconomical repetition of burning have been necessary to avoid the melting of clinker by eutectic reaction in the system $CaO-Al_2O_3$. In this study, special starting raw materials for the clinker burning were prepared from a mixture of oyster shell and aluminium hydroxide by heating to $1100^{\circ}C$ and hydrating at $30^{\circ}C$. The starting raw materials, hardened body with weak hydraulic strength, were mainly composed of $C_3AH_6$ formed by resolution-precipitation mechanism of the system $CaO-Al_2O_3-H_2O$. By heating them, relatively pure $C_3A$ clinker could be obtained by one-time burning at the fairly lower temperature than that of conventional method. The easier formation of $C_3A$ clinker seemed to be caused by higher compositional homogeneity and stoichiometry of the starting materials, high surface area and crystallographic instability of the thermally decomposed products, and the catalytic effect of decomposed moisture on the early-stage crystallization of calciumaluminates. The basic hydration behavior of the clinker was also confirmed.

• Journal of Korean Society on Water Environment
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• v.32 no.2
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• pp.216-221
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• 2016

The adsorption characteristics of mixed heavy metals (Cr(III), As(VI)) in aqueous solution were investigated using a sediment amendment composite. Sediment amendment composite was composed of clean sediment (40%), zeolite (20%), recycled aggregate (10%), steel slag (10%), oyster shell (10%), and cement (10%). The experimental results showed that the adsorption equilibrium was attained after 180 mins. Heavy metal adsorption was characterized using Freundlich and Langmuir equations. The equilibrium adsorption data for the sediment amendment composite better fitted with the Langmuir model than the Freundlich model. The maximum adsorption capacity of Cr(VI) (36.07 mg/g) was higher than As(III) (25.54 mg/g); and the adsorption efficiency of the Cr(VI) and As(III) ions solution decreased with decreasing pH from 2 to 10. The collective results suggested that the sediment amendment composite is a promising material for a reactive cap that controls the release of Cr(VI) and As(III) from contaminated sediments.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.53-57
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• 2018

고도의 산업화에 따라 도시의 성장과 인구의 밀집으로 인하여 물의 수요가 증가하고 이에 따라 각종 오염원의 유입이 증가함에 따라서 적절한 수질 관리에 대한 필요성이 대두되고 있다. 그리고 산업이 다양화됨에 따라 배출되는 하 폐수의 특성도 다양해져 기존의 수질처리장은 효율적인 처리를 하는데 있어 많은 어려움이 발생되고 있다. 굴 패각은 하수처리의 담체로 이용할 경우 살수여상의 문제점 중 하나로 나타나는 막힘 현상을 다소 감소시킬 수 있고, 다공질체로서 표면적이 불규칙하고 비표면적이 크기 때문에 반응기내에 공기를 원활하게 공급할 수 있으며, 중금속 이온과 유기물에 대한 흡착 효율이 뛰어나 미생물이 쉽게 부착, 성장할 수 있는 장점을 가지고 있다. 천연광물질은 전 세계적으로 발견되어 활용된 역사가 짧지만, 그 특징은 산소결핍보충, 유해원소 흡착 성능, 반도체 작용, 인체 면역력 강화, 바이러스성 질병의 예방, 중금속 해독 등의 다양한 특징으로 환경호르몬 제고, 음이온 원적외선 발생으로 세포의 노화방지, 인체 노폐물 제거와 같은 특징을 지닌 매우 유용한 자원으로 확인되고 있으며, 수질정화 능력이 탁월한 것으로 보고 있다. 이에 본 연구는 어촌폐기물인 굴 패각과 수질정화에 탁월한 천연 광물질을 혼합하여 경제적이고, 효율성이 높은 다공성 수질개선 담체를 개발하고, 수목여과용 비점오염시설 장치에 적용하여 혼합 담체가 수처리 시설의 담체로서 사용이 가능한지, 수목여과용 비점오염시설 장치에 적용할 수 있는지 검토하고자 수행하였다. 이 연구는 2017년 중소기업청 기술개발사업에서 연구지원을 받아 연구되었습니다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.497-504
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• 2013

This study examined the characteristics of ionized calcium and in vitro calcium bioavailability rate of calcium from four natural sources: shellfish shell, oyster shell, starfish, egg shell. The levels of dissolved calcium and calcium ions increased at different concentrations of natural calcium (up to 8.0% (w/v)). However, there were insignificant differences in the levels of dissolved calcium and calcium ions between samples at calcium concentrations above 8.0% (w/v). In addition, no significant differences were observed (depending on the calcium source and concentration) with an ionization yield of about 90%. The temperature of the solutions also had little influence on the ionization of calcium. The highest calcium ion content was observed when solutions were left to dissolve calcium for 18 hours. The highest in vitro calcium bioavailability rate achieved among the different calcium solutions was BS (67.3%), with overall bioavailability rates about two times higher than the rates observed in commercially sold calcium supplements and natural calcium. In addition, the in vitro calcium bioavailability rate for ionized calcium in market milk, soy milk, and orange juice was more than twice as high as calcium carbonate. Overall, we expect a high and diverse bioavailability of ionized calcium from natural resources.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1398-1406
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• 2004

To develop the new type of salt-fermented seafoods, the salt-fermented oysters in olive oil (product SO) were manufactured, and food components and quality characteristics of product SO were examined. The optimum processing condition for product SO is as follows. The raw oyster with no shell was washed off with 3% saline solution. Then dewatered, and dipped in the brine-salting solution made up with saturated saline solution and oyster sauce (2 : 1 v/v) mixture added 1% sodium erythorbic acid and 0.2% polyphosphate. After salt-fermentation it ripened by brine salting at 5$\pm$1$^{\circ}C$ for 15 days. Then dried at 15$^{\circ}C$ for 4 hours with cool-air, and packed in No. 3B hexahedron type can. Finally, poured with olive oil and seamed it by double-seamer. The moisture, crude protein, crude ash and volatile basic nitrogen contents of the product SO were 61.6%, 12.0%, 16.3% and 34.3 mg/100 g, respectively. In taste-active components of the product SO, total amount of free amino acids is 2,335.4 mg/100 g and it has increased by 50% overall during salt-fermentation 15 day. Taurine, glutamic acid, proline, glycine, alanine, $\beta$-alanine and lysine were detected as principal free amino acids. The contents of inorganic ions were rich in Na and K ion, while the amounts of nucleotide and its related compounds and other bases except betaine were small. From the results of this research, the product SO had a superior organoleptic qualities compared with conventional oyster product, and could be reserved in good conditions for storage 90 days at room temperature.

• The Korean Journal of Mycology
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• v.27 no.1 s.88
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• pp.10-14
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• 1999

A single phase composter was constructed by modifying the conventional mixer of sawdust for the cultivation of oyster mushroom Pleurotus ostreatus. The machine was designed on the basis of 3-phase-1 system which was controlled in prewetting, pasteurization and fermentation processes. In composting 200 kg of straw and cotton waste in the machine, it took 20 minutes in prewetting step and also to hours at $65^{\circ}C$ in pasteurization process. Postfermentation by aerothermophiles was completed by treating the compost at $45^{\circ}C-50^{\circ}C$ for 48 hours which was shorten 24 hours from the conventional method. In the postfermentation at high temperature, forced aeration and/or vigorous mixing process(es) played a great role in the improvement of spawn quality. The growth of mycelium of oyster mushroom was excellent in the culture combinated with 3 parts of surface inoculation and 7 parts of mechanical mixing.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.27-34
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• 2008

To effectively treat the domestic sewage that was produced on a small-scale in farming and fishing village in order to encourage an ecologically friendly environment, a small-scale sewage treatment apparatus using natural purification methods that consisted of an aerobic and an anaerobic plots were constructed. The efficiency of sewage treatment according to the sewage loading was investigated to obtain the optimum sewage loading in small-scale sewage treatment apparatus. Removal rate of pollutants according to the sewage loading were in the order of $150\;Lm^{-2}day^{-1}{\fallingdotseq}300\;Lm^{-2}day^{-1}>600\;Lm^{-2}day^{-1}$. Therefore, the optimum sewage loading was 300 L m-2 day-1. Under the optimum sewage loading, removal rate of BOD, $COD_{Mn}$, turbidity, T-N and T-P were 99, 94, 99, 49 and 89%, respectively. However, to satisfy the water quality standard in effluent in small-sclae sewage treatment apparatus for domestic sewage treatment, the low removal efficiency of T-N and T-P must be improved. So to improve the removal rate of T-N and T-P, the efficiency of sewage treatment according to the improved sewage treatment process such as, re-treatment at aerobic plot, anaerobic condition of aerobic plot, changing the filter media sizes and the depths in anaerobic plot, and also addition of oyster shells to filter media at anaerobic plot were investigated. In case of 150 cm depth in anaerobic plot with filter medium A (effectivity particle size 1.50 mm) and addition of oyster shells to filter media at anaerobic plot, removal rate of T-N and T-P in both plots were increased by 10 and 3%, and 14 and 7% in comparison with 100 cm depth in anaerobic plot with filter medium B(effectivity particle size 0.95 mm), respectively. The optimum improved sewage treatment process in small-scale sewage treatment apparatus were 150 cm depth in anaerobic plot with filter medium A and addition of oyster shells to filter media at anaerobic plot.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.7
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• pp.926-931
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• 2007

Diarrhetic shellfish poisons (DSP) such as okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-1(PTX1), PTX2, PTX6 and yessotoxin (YTX) were determined simultaneously by LC-MS/MS and mouse bioassay in the shellfishes (oyster, mussel, Washington purple clam, ark shell, scallop and short necked clam) collected at Tongyeong, from March to September, 2006. Oyster and mussel were found to contain DSP (0.05${\sim}$0.1 MU/g) in March by mouse bioassay; however, no DSP components were detected on the LC-MS/MS. Also, a small amount of DTX1 (0.05 ${\mu}g/g$) in mussel (June) and OA (0.01${\sim}$0.02 ${\mu}g/g$) in 5 species of shellfishes(August) were determined by LC-MS/MS.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.899-909
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• 2023

In this study, the material scientific characteristics of Hobun pigments used as white inorganic pigment for traditional cultural heritage were identified according to the type of shell and calcination and evaluated the stability of the preservation environment. For the purpose of this, we collected 2 different types of Hobun pigments made by oyster and clam shell and its calcined products(at 1,150℃). Hobun pigments before calcined identified calcium carbonate such as calcite, aragonite but calcination derived changing main composition to portlandite and calcite. Results of FE-SEM showed characteristics microstructure for each shell but pigments after calcined observed porous structure. Porous granule highly caused oil adsorption according to increase specific surface area of pigments. In addition, the whiteness improved after calcined pigments compared to non-calcined pigments, and the color improvement rate of Hobun pigment (CS) which made of clam shell was higher. As a result of the accelerated weathering test, the Hobun pigment-colored specimen had a color difference value of less than 2 after the test, which was difficult to recognize with the naked eye. In particular, the color stability has improved as the color difference value of the Hobun pigment is smaller after calcined compared to before non-calcined pigment. However, it was confirmed that the stability of the painting layer was lower in the specimen after calcined pigment. For antifungal activity test, Aspergillus niger, Tyromyces palustris and Trametes versicolor were used as test fungi, and all pigments were found to have preventive and protective effects against fungi. Especially, the antifungal effect of the calcined pigment was excellent, which is due to the stronger basicity of the pigment.