• 한국식품영양과학회지
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• 제33권5호
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• pp.864-868
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• 2004

철분은 생체 내에서 이루어지는 거의 모든 대사에 필수적인 성분이지만, 식음에 포함된 철분의 양은 극히 적어서 철분강화에 대한 연구가 꾸준히 진행되어 왔다. 이에 따라， 철분공여물질을 함유한 리포즘을 이용하여 철분 강화 식품첨가제를 개발하였다. 철분공여물질로 ferrous sulfate와 hemin을 사용하였으며, 이러한 철분 함유 리포좀을 제조하는데 가장 큰 문제점은 ferrous sulfate의 자체 산화와 ferrous sul fate와 hemin으로 인한 리포좀의 지질산화로 지적되었다 또한, ferrous sulfate에 의한 리포좀의 산화 정도는 hemin의 경우보다 낮은 것으로 관찰되었다. Ferrous sulfate의 자동 산화를 억제하기 위하여 수용성 항산화제인 ascorbic acid가 첨가되었으나, 첨가된 ascorbic acid는 ferrous sulfate와 hemin을 함유한 리포좀의 산화를 억제시키지 못했으며, 오히려 ferrous sulfate에 의한 리포좀의 산화를 촉진시키는 것으로 관찰되었다 여기에 지용성 항산화제인 $\alpha$-tocopherol을 추가적으로 첨가함으로써, ferrous sulfate의 자동산화를 억제하고 hemin과 ferrous sulfate에 의한 리포좀의 산화가 억제된 철분 함유 리포좀이 제조되었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제20권3호
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• pp.217-227
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• 1998

Calcium sulfate(plaster of Paris) has been used in dental and orthopedic surgery for about 100 years. It is well known that the plaster is bioresorbable, biocompatible, defect conformable and moldable. The purpose of this study is to evaluate two effects of calcium sulfate on bone regeneration, that is, the effects of graft materials and barrier for bone regeneration. Cortical bone defects were formed for recipient site on the femurs of 19 Sprague-Dawley rats. The autogenous particulated bone and calcium sulfate were grafted to the defects. Calcium sulfate paste, $Gore-Tex^R$ membrane(W.L. GORE & ASSOCIATES LTD., U.S.A.) and rubber sheet were used for the shielding materials. The results were as follows : 1. Calcium sulfate that had been grafted in the cortical bone defect was almost resorbed before bone remodeling, resultantly had little effect on bone regeneration. 2. Resoption process of calcium sulfate grafted on the bone grafting area tends to be accelerated, as being divided into numerous small particles progressively. Under the situation where the calcium sulfate was protected, with the coverage of fascia, $Gore-Tex^R$ membrane or rubber sheet, new bone formation was confirmed with presence of calcium sulfate particles over 6 weeks after grafting. 3. In the case of calcium sulfate covered with membrane, distinct bone formation was observed on the marrow space of femur adjacent to the plaster mass. 4. Rubber shielded plaster group revealed new bone trabeculae under the rubber sheet, but it showed ischemic degeneration of superficial cortical bone.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.508-513
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• 2001

Recently, ground granulated blast-furnace slag (GGBFS) has been increasingly used as additive for concrete. Many researchers reported that concrete using GGBFS had a better resistance under severe environments, such as marine or sulfate-rich soils, than Portland type cement concrete. The aim, therefore, of this study is to evaluate on the effectiveness of concrete using GGBFS when the concrete exposes to sulfate-rich environment. The detailed items for experiments show 2 series consisted of sulfate immersion test with mortar and sulfate diffusion test with concrete. The sulfate immersion test was performed for 400 days and contained reduction of compressive strength, length change and XRD analysis. For sulfate diffusion test, sulfate ions diffusivity was calculated on tile consideration of electrochemical theory by the diffusion cell test. As the results of this study, it was found that the concrete using GGBFS as additive was superior to portland type cement concrete. Consequently, the use of concrete with GGBFS for recycling may expect the durable and economical benefits.

• 상하수도학회지
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• 제13권2호
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• pp.47-54
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• 1999

SRB(Sulfate Reducing Bacteria) converts sulfate into sulfide using an organic carbon source as the electron donor. The sulfide formed precipitates the various metals present in the AMD (Acid Mine Drainage). This study is the fundamental research on heavy metal removal from AMD using SRB. Two completely mixed anaerobic reactors were operated for cultivation of SRB at the temperature of $30^{\circ}C$ and anaerobic batch reactors were used to evaluate the effects of carbon source, COD/sulfate($SO_4^=$) ratio and alkalinity on sulfate reduction rate and heavy metal removal efficiency. AMD used in this study was characterized by low pH 3.0 and 1000mg/l of sulfate and dissolved high concentration of heavy metals such as iron, cadmium, copper, zinc and lead. It was found that glucose was an organic carbon source better than acetate as the electron donor of SRB for sulfate reduction in AMD. Amount of sulfate reduction maximized at the COD(glucose)/sulfate ratio of 0.5 in the influent and then removal efficiencies of heavy metals were 97.5% of Cu, 100% of Pb, 100% of Cr, 49% of Mn, 98% of Zn, 100% Cd and 92.4% of Fe. Although sulfate reduction results in an increase in the alkalinity of the reactor, alkalinity of 1000mg/1 (as $CaCo_3$) should be should be added continuously to the anaerobic reactor in order to remove heavy metals from AMD.

• 한국염색가공학회지
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• 제14권2호
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• pp.40-50
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• 2002

In order to remove the pollutants effectively in the dye wastewater by chemical precipitation process, coagulation arid flocculation test were carried out using several coagulants on various reaction conditions. It was found that the Ferrous sulfate was the most effective coagulant for the removal of disperse dye(B79), and we could get the best result lot the removal of disperse dye(B56) in the aspects of TOC removal efficiency and sludge field. When the Ferrous sulfate dosage was $800mg/\ell$, the sludge settling velocity was very fast>, and the color was effectively removed in the disperse dye(B79) solution. Although the color removal was ineffective when the Alum was used as a coagulant, the sludge field was decreased in comparison with the Ferrous sulfate or the Ferric sulfate was used in the disperse dye(B56) solution. The general color removal effect for the disperse dye(B56 and B79) solutions, the Ferric sulfate was more proper coagulant than the Alum. It was showed that TOC removal was improved 5% and over by the addition of Calcium hydroxide, and $30mg/\ell$ of sludge yield was decreased(B79). When Alum or Ferric sulfate was used as a coagulant, pH condition for most effective color removal was 5 in B56 solution. In case of Ferrous sulfate as a coagulant, most effective pH condition for color removal was 9. When Ferric sulfate or Ferrous sulfate was used as a coagulant, pH condition for most effective color removal was 9 in B79 solution.

• 한국식품영양과학회지
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• 제24권3호
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• pp.446-453
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• 1995

The improtant components of extracellular matrix(ECM) are collagen and chondroitin sulfate. The hydrophobic surface of collagen is one of the determining factors of diameter of collagen fiber and also is closely related to the aging phenomena. The controlling mechanism of the diameter of collagen fiber influenced by the interaction with chondroitin sulfate was evaluated using bis-ANS as a hydrophobic probe. Hydrophobic surface area of collagen molecule shielded by chondroitin sulfate was evaluated. Relative fluorescence intensity of collagen in thepresence of chondroitin sulfate was measured using bis-ANS as a hydrophobic probe. The fluorescence intensity decreased with the increase in chondroitin sulfate up to 3.8 chondroitin sulfate/collagen(mole/mole). Further increase in the ratio of chondroitin sulfate to collagen did not change the fluorescence intensity. Similar changes in the relative fluorescence intensity were observed for both rat tail and lathyrific rat skin collagen. The fluorescence intensity indicated by the binding between bis-ANS and hydrophobic sites of collagen was pH dependent, and the shielding effect of collagen-chondroitin sulfate interaction could not be detected at pH above 6.0. This is probably due to the charge repulsions caused by negative charged collagen molecules at higher pH.

• Bulletin of the Korean Chemical Society
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• 제5권6호
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• pp.249-253
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• 1984

Mutual diffusion coefficients of choline chloride were determined by using the diaphragm cell method in aqueous solutions of chondroitin sulfate A at $25^{\circ}C$. The diffusion coefficients of choline chloride in 0.1g/100ml, 0.5g/100ml and 1g/100ml respectively of chondroitin sulfate solutions were compared with those of binary systems of water-choline chloride. At low concentrations, the diffusion coefficients of the choline chloride in the presence of chondroitin sulfate were significantly smaller than the values obtained in the absence of chondroitin sulfate, indicating a strong interaction between these solutes. The effect of this interaction on the diffusion of choline ion is largest at higher chondroitin sulfate concentrations and at lower choline chloride concentrations. The influence of chondroitin sulfate is overcome at higher choline chloride concentrations. Self-diffusion coefficients of choline ion in the presence of chondroitin sulfate are also obtained. Excellent agreements were obtained between the experimental data and the calculated values obtained by using the Manning's equations. These observations suggest that the interaction between choline chloride and chondroitin sulfate involves primarily a long range electrostatic effect and there is no appreciable "condensation" or binding of choline ion to the chondroitin sulfate.

• Computers and Concrete
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• 제29권 5호
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• pp.335-346
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• 2022

Geopolymers are an important alternative material supporting recycling, sustainability, and waste management. Durability properties are among the most critical parameters to be investigated; in this study, the durability of manufactured geopolymer samples under the attack of 10% magnesium sulfate and 10% sodium sulfate solution was investigated. 180 cycles of freezing and thawing were also tested. The experimentally obtained results investigate the durability of geopolymer mortar prepared with fly ash (class F) and alkali activator. Three different quarry dust wastes replaced the river sand aggregate: limestone, marble, and basalt powder as fine filler aggregate in three different replacement ratios of 25%, 50%, and 75% to produce ten series of geopolymer composites. The geopolymer samples' visual appearance, weight changes, UPV, and strength properties were studied for up to 12 months at different time intervals of exposure to sulfate solutions to investigate sulfate resistance. In addition, Scanning Electron Microscopy (SEM), EDS, and XRD were used to study the microstructure of the samples. It was beneficial to include quarry waste as a filler aggregate in durability and mechanical properties. The compact matrix was demonstrated by microstructural analysis of the manufactured specimens. The geopolymer mortars immersed in sodium sulfate showed less strength reduction and deterioration than magnesium sulfate, indicating that magnesium sulfate is more aggressive than sodium sulfate. Therefore, it is concluded that using waste dust interrogation with partial replacement of river sand with fly ash-based geopolymers has satisfactory results in terms of durability properties of freeze-thaw and sulfate resistance.

• Journal of Periodontal and Implant Science
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• 제27권4호
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• pp.785-804
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• 1997

It was well known that calcium sulfate was biocompatible, resorbed rapidly in the body, had potential as a good barrier membrane. Platelet-derived growth factor(PDGF) was one of polypeptide growth factor that had been reported as a biological mediator which regulates activities of wound healing process including the cell proliferation, migration and metabolism. The purpose of this study was to evaluate the effects of a combination of calcium sulfate and PDGF on periodontal ligament cells in vitro to use as a regeneration promoting agent of periodontal tissue. Human periodontal ligament cells were prepared from the premolar tooth extracted for the orthodontic treatment. Cells were cultured in ${\alpha}-MEM$ contained with 20% FBS, at the $37^{\circ}C$, 100% of humidity, 5% $Co_2$ incubator. Cells were inoculated and cultured into 96 well culture plate with $1{\times}10^4cells/well$ of ${\alpha}-MEM$ for 1 day. After discarding the medium, those cells were cultured in ${\alpha}-MEM$ contained with 10% FBS alone(control group), in calcium sulfate(calcium sulfate group), in calcium sulfate treated with 15ng/ml of PDGF-BB(calcium sulfate+PDGF group), in ${\alpha}-MEM$ contained with 10% FBS treated with 15ng/ml of PDGF-BB(PDGF group) for 1, 2, 3 day respectively. And then each group was characterized by examining of the cell counting, MTT assay, collagen synthesis. The results were as follows. 1. In the analysis of cell proliferation by cell counting, both calcium sulfate group and calcium sulfate plus PDGF group showed no stastically significant difference compared to control group, but there was stastically significant difference between PDGF group and calcium sulfate group at 1, 2 day(P<0.05). 2. In the analysis of cell proliferation by MTT assay in calcium sulfate extracts, both calcium sulfate group and calcium sulfate plus PDGF group showed no stastically significant difference compared to control group, but there was stastically significant difference between PDGF group and calcium sulfate group at 2, 3 day, and between calcium sulfate plus PDGF group and calcium sulfate group at 2 day(P

• 한국대기환경학회지
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• 제2권1호
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• pp.33-39
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• 1986

Particulate matter was collected by Andersen Air Sampler in the Seoul area during February-October, 1985, in order to investigate size distribution of sulfate and nitrate in aerosol, and conversion of sulfur dioxide to sulfate and that of nitrogen dioxide to nitrate. The size distribution of sulfate and nitrate had fine mode. The ratio of fine sulfate to total sulfate in aerosol and that of fine nitrate to total nitrate showed between 54.6% and 86%, and 55.7% and 95%, respectively, which presumably originated from gaseous reaction of sulfur dioxide and nitrogen dioxide in the atmosphere.