• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.176-184
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• 2018

In the present study, we investigated the antioxidative properties, cellular protective effects and component analyses of 50% ethanol extract, ethyl acetate fraction and aglycone fraction obtained from Lysimachia christinae Hance (L. christinae Hance). In the evaluation of antioxidative properties, the free radical scavenging activities ($FSC_{50}$) of 50% ethanol extract, ethyl acetate fraction and aglycone fraction were 146.8, 22.2 and $27.2{\mu}g/mL$, respectively and total antioxidant capacities ($OSC_{50}$) were 29.3, 2.9 and $4.5{\mu}g/mL$, respectively. The ethyl acetate fraction showed the highest free radical scavenging activity and total antioxidant capacity. Also, the cellular protective effects (${\tau}_{50}$) of 50% ethanol extract, ethyl acetate fraction and aglycone fraction on $^1O_2$ induced photohemolysis of human erythrocytes were 26.9, 57.5 and 103.9 min at $5{\mu}g/mL$, respectively. In particular, ${\tau}_{50}$ of the aglycone fraction exhibited a higher cellular protective effect than that of (+)-${\alpha}$-tocopherol (37.7 min). The cell viability of the ethyl acetate fraction on the UVB-induced cell damage increased up to 90.1%. In addition, the ethyl acetate fraction ($5-25{\mu}g/mL$) showed cellular protective effects on the $H_2O_2-induced$ cell damages in a dose-dependent manner. TLC, HPLC, UV-vis spectroscopy and LC-MS were used to analyse components of the ethyl acetate fraction and the main components were quercetin, kaempferol and their glycosides. In conclusion, L. christinae Hance extract/fraction can function as antioxidants to protect the skin exposed to UV radiation and may also be used as a novel functional cosmetic material, for example, an antioxidant against skin photoaging.

• Journal of Chest Surgery
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• v.43 no.3
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• pp.235-245
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• 2010

Background: Our goal was to evaluate anti-calcification effects of decellularization and diverse fixing methods including preincubation of the bovine pericardium with ethanol. We also assessed changes in mechanical properties. Material and Method: Harvested bovine pericardium was decellularized with 0.25% sodim dodecysulfate and then treated with 5 methods of fixation: (1) 0.5% glutaraldehyde (GA) for 14 days, (2) 0.5% GA for 5 days, 2% GA for 2 days and 0.25% GA for 7 days, (3) 0.5% GA for 5 days, 2% GA for 2 days, 0.25% GA for 7 days, and then 70% ethanol for 2 days, (4) 0.5% GA for 5 days, a mixture of 2% GA and 70% ethanol for 2 days, and 0.25% GA for 7 days, (5) 0.5% GA for 5 days, a mixture of 2% GA, 65% ethanol, and 5% octanediol for 2 days and then 0.25% GA for 7 days. All treated bovine pericardia were tested for histological variables, lipid content, and mechanical properties including tensile strength and thermal stability. A total 10 kinds of differently treated bovine pericardia were implanted into rat subdermis and harvested 8 weeks later. Harvested pericardia were evaluated for calcium content. Result: No protein denaturation was observed microscopically after decellularization. There was a 32% mean decrease in tensile strength index after decellularization in the bovine pericardium group fixed. Octanediol preincubation attenuated the decrease in tensile strength and maintained thermal stability. TG and cholesterol were not affected by decellularization but were decreased by organic solvent. Calcium content was decreased after decellularization, and organic solvent preincubation decreased calcification in the non-decellularized bovine pericardium group. Conclusion: Decellularization and organic solvent preincubation have anti-calcification effects but decellularization may cause mechanical instability. A method of decellularization and fixation that does not cause damage to matrices will be needed for evaluation of the next step in using tissue-engineering for replacement of cardiac valves.

• The Korean Journal of Food And Nutrition
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• v.25 no.3
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• pp.564-569
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• 2012

Selenium was initially considered toxic to humans, but it was then discovered that selenium is essential for normal life processes. Selenium plays important roles in antioxidants. It is expected that chitosan microcapsules containing nano-selenium will be able to be used as a key material in bio-medical and cosmetic applications. The high concentration of chitosan derivatives guarantees increased antioxidative activity. Both inorganic and organic forms of selenium can be nutritional sources. The antioxidant properties of selenoproteins help prevent cellular damage from free radicals. The objective of this experiment was to study the antioxidative activity of chitosan nano-selenium. Our experiments were divided into five groups, in the presence of various concentrations(0.1%, 0.3%, 0.5%, 0.7%, and 0.9%) of chitosan. We performed an assessment of the antioxidant properties and cytotoxicity of respective concentrations of chitosan nano-selenium. The antioxidant activity was examined by the free radical scavenging activity on 1,1-diphenyl-2-picrylhydrazyl(DPPH) assay. The cytotoxicity effect was measured by means of 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay. As a result, the electron donating abilities of 0.1%, 0.3%, 0.5%, 0.7%, and 0.9% of chitosan nano-selenium exhibited effective andioxidant scavenging activity at 12.5 ${\mu}g/m{\ell}$ against DPPH radicals. 0.3% chitosan nano-selenium did not show cytotoxicity on human keratinocytes. In general, the cytotoxicity of 0.1% and 0.9% chitosan nano-selenium showed the lowest effects. Though low cytotoxicity of 0.5% and 0.7% chitosan nano-selenium exhibited 29.67% and 38.4% against human keratinocytes on adding 100 ${\mu}g/m{\ell}$ and 50 ${\mu}g/m{\ell}$, respectively, cell vitality was recovered with 200 ${\mu}g/m{\ell}$. These findings support the notion that chitosan nano-selenium may be useful as a new active ingredient source for bioactive compounds.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.148-156
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• 2015

In this study the differences in the sample size and sample input changes as characteristics of bio-oil oak(Quercus variabilis), the oak 0.5~2.0 mm of the oak weighing 300~900g was processed into bio-oil via fast pyrolysis for 1.64 seconds. In this study, the physico-chemical properties of biooil using oak were investigated. Fast pyrolysis was adopted to increase the bio-oil yield from raw material. Although the differences in sample size and sample input changes in the yield of pyrolysis products were not significantly noticeable, increases in the yield of bio-oil accounted for approximately 60.3 to 62.1%, in the order of non-condensed gas, and biochar. When the primary bio-oil obtained by the condensation of the cooling tube and the seconary bio-oil obtained from the electric dust collector were measured separately, the yield of primary bio-oil was twice as higher than that of the secondary bio-oil. However, HHV (Higher Heating Value) of the secondary bio-oil was approximately twice as higher than that of the primary bio-oil by up to 5,602 kcal/kg. The water content of the primary bio-oil was more than 20% of the moisture content of the secondary bio-oil, which was 10% or less. In addition, the result of the elemental analysis regarding the secondary bio-oil, its primary carbon content was higher than that of the primary bio-oil, and since the oxygen content is low, the water content as well as elemental composition are believed to have an effect on the calorific value. The higher the storage temperature or the longer the storage period, the degree of the viscosity of the secondary bio-oil was higher than that of the primary bio-oil. This can be the attributed to the chemical bond between the polymeric bio-oil that forms during the storage period.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.4
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• pp.15-24
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• 2019

The study was compared for soil chemical and microbial properties as well as growth of the cherry tomato (Lycopersicon esculentum var. cerasiforme) plants environmentally friendly gown for 3 years and 5 years, which had been fertigated with homemade liquid fertilizer (LF) with indigenous microorganism as an additional fertilizer. Treatment included LF with indigenous microorganism for 3 years (3-year IM-LF) and for 5 years (5-year IM-LF), with an effective microorganism for 10 years (EM-LF), which had been applied with 1,000 times of dilution in the farmhouse. IM-LF and EM-LF materials had increased pH pattern for 16 weeks, in particular for increase of 1.2 for EM-LF. IM-LF material contained slightly higher EC but similar level of 0.2 dS/m to EM-LF. For a pot experiment in the greenhouse, IM-LF treatment increased root dry weight of the cherry tomato plants. In the farmhouse experiment, IM-LF treatment increased to 7.5 of soil pH and 8.4 dS/m of EC, indicating high salt accumulation. EM-LF treatment increased to 62 g/kg of soil OM, which would have affected concentrations of macro essential nutrients, including T-N in the soil. However, the optimum soil chemical levels for growth of cherry tomato plants were observed on the IM-LF plots. EM-LF treatment increased number of bacteria and actinobacteria in the soil. EM-LF treatment increased concentrations of macro essential nutrients in the plants, except for P, with similar nutrient concentrations observed between 3-year IM-LF and 5-year IM-LF-treated plants. Leaf SPAD and PS II levels decreased in the plants treated with 3-year IM-LF. EM-LF treatment increased leaf width and length, number of leaves, canopy area, plant height, and stem diameter in the mid-term stage of growth, which were not significantly different between the treatments. EM-LF treated-plants had two times higher leaf dry weight than those of values observed on the IM-LF plants, which was the opposite result observed on the number of fruit.

• Restorative Dentistry and Endodontics
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• v.14 no.1
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• pp.41-56
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• 1989

The purpose of this study was to examine the effect of temperature dependence of the behavior on the physical properties of posterior composite resins. Three light cure posterior composite resins (Heliomolar, Litefil-P, and P-50) and one chemical cure posterior composite resin (Bisfil-II) were used as experimental materials. Composite resin was placed in a cylindrical brass mold (2.5 mm high and 6.5 mm inside diameter) that was rested on a glass plate. Another flat glass was placed on top of the mold, and the plate was tightly clamped together. After the mold had been filled with the light cure composite material, the top surface was cured for 30 seconds with a light source. Chemical cure resin specimens were made in the same manner as above. Three hundreds and twenty composite resin specimens were constructed from the four composite materials. One hundred and sixty specimens of them were placed in a heater at $50^{\circ}C$, $75^{\circ}C$, $100^{\circ}C$, $125^{\circ}C$, $150^{\circ}C$, $175^{\circ}C$ and $200^{\circ}C$ for 5 minutes or 10 minutes respectively before compressive strengths were measured. Another one hundred and sixty specimens were tested for the diametral tensile strengths in the same way as above. They were randomly divided into eight groups according to the mode of heating methods as follows and stored in distilled water at $37^{\circ}C$ for 24 hours. Group $37^{\circ}C$ - specimens were stored at $37^{\circ}C$ in distilled water for 24 hours. Group $50^{\circ}C$ - specimens were heated at $50^{\circ}C$ after curing. Group $75^{\circ}C$ - specimens were heated at $75^{\circ}C$ after curing. Group $100^{\circ}C$ - specimens were heated at $100^{\circ}C$ after curing. Group $125^{\circ}C$ - specimens were heated at $125^{\circ}C$ after curing. Group $150^{\circ}C$ - specimens were heated at $150^{\circ}C$ after curing. Group $175^{\circ}C$ - specimens were heated at $175^{\circ}C$ after curing. Group $200^{\circ}C$ - specimens were heated at $200^{\circ}C$ after curing. Twenty specimens of each of four composite resins were respectively made by insertion of materials into same mold for examining the dimensional changes between before and after heating. The final eighty specimens were stored in distilled water at $37^{\circ}C$ for 24 hours before testing the dimensional changes. Compressive and diametral tensile strengths were measured crosshead speed 1mm/minute and 500Kg in full scale with a mechanical testing machine (DLC 500 Type, Shimadzu Co., Japan). Dimensional changes were determined by measuring the diametral changes of eighty specimens with micrometer (Mitutoyo Co., Japan). Results were as follows: 1. Diametral tensile strengths of specimens in all groups were increased with time heated compared with control group except for that in group $50^{\circ}C$ and the maximum diametral tensile strength was appeared in the specimen of Litefil-P heated for 10 minutes at $100^{\circ}C$. In heliomolar and P-50, it could be seen in the specimen heated for 10 minutes at $150^{\circ}C$, but in Bisfil-II, it could be found in the specimen heated for 5 minutes at $150^{\circ}C$. 2. Compressive strengths of specimens in all groups was tended to be also increased with time heated but that in group $50^{\circ}C$ and the maximum compressive strengths were showed in the same specimens conditioned as the diametral tensile strengths of four composite materials tested. 3. In Heliomolar, Litefil-P, and Bisfil-II, it was decreased in diameters of resin specimens between before heating and increased in diameters of resin specimens after storing in distilled water, but it was not in P-50. 4. There is little difference in diametral tensile strengths, compressive strengths, and dimensional changes followed by heating the resin specimens for 5 minutes and 10 minutes, but there is no statistical significances.

• Applied Biological Chemistry
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• v.15 no.2
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• pp.169-173
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• 1972

In five varietes of Citrus junos sieb grown in different area in Korea, the general components, total acids and inorganic components were calculated and compared with one other. In the orchard soils, the physical and chemical properties were studied. The results are summarized as follow: 1. Generally, the rind was weighter than tile flesh compared with the other fruits and the proportion of the rind was 49%. 2. Total contents of organic acids in rind and flesh were 12.29me and 39.79me respectively. 3. The order of the contents of inorganic components in the flesh and rind was $CaO>K_2O>MgO>P_2O_5>SO_4$ 4. The contents of crude protein and crude fat were increased with those of MgO and $SO_4$ in fruits. 5. The quantity of protein in the soil seed to influence greatly in rind formation not only in citrus fruits but also Citrus junos sieb. 6. In growing Citrus junos sieb, C.L. seemed to he the most adequate soil. 7. The pH range of the soil was from 5.05 to 7.20 generally. 8. The contents of crude protein and crude fat in citrus fruits seemed to be increased with those of organic material and total-nitrogen in the soil.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.625-639
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• 2019

Microplastics are one of the substances threatening the marine ecosystem. Here, we summarize the status of research on the effect of microplastics on marine life and suggest future research directions. Microplastics are synthetic polymeric compounds smaller than 5 mm and these materials released into the environment are not only physically small but do not decompose over time. Thus, they accumulate extensively on land, from the coast to the sea, and from the surface to the deep sea. Microplastic can be ingested and accumulated in marine life. Furthermore, the elution of chemicals added to plastic represents another risk. Microplastics accumulated in the ocean affect the growth, development, behavior, reproduction, and death of marine life. However, the properties of microplastics vary widely in size, material, shape, and other aspects and toxicity tests conducted on several properties of microplastics cannot represent the hazards of all other microplastics. It is necessary to evaluate the risks according to the types of microplastic, but due to their variety and the lack of uniformity in research results, it is difficult to compare and analyze the results of previous studies. Therefore, it is necessary to derive a standard test method to estimate the biological risk from different types of microplastics. In addition, while most of the previous studies were conducted mostly on spheres for the convenience of the experiments, they do not properly reflect the reality that fibers and fragments are the main forms of microplastics in the marine environment and in fish and shellfish. Furthermore, studies have been conducted on additives and POPs (persistent organic pollutants) in plastics, but little is known about their toxic effects on the body. The effects of microplastics on the marine ecosystems and humans could be identified in more detail if standard testing methods are developed, microplastics in the form of fibers and fragments rather than spheres are tested, and additives and POPs are analyzed. These investigations will allow us to identify the impact of microplastics on marine ecosystems and humans in more detail.

• Food Science and Preservation
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• v.22 no.6
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• pp.838-844
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• 2015

The purpose of this study was to perform a functional components analysis and investigate the physical properties of powders made from the stems or fruit of freeze-dried Cheonnyuncho cactus (Opuntia humifusa). The functional components analysis showed that the stem and fruit powders han vitamin C levels of 42.14 mg and 105.21 mg, respectively. The stems powder contained more lutein than the fruit powder. The fruit powder contained more vitamin C than the stem powder. The SDF (soluble dietary fiber) and IDF (insoluble dietary fiber) in the stem powder were 45.24% and 22.15%, respectively, which were higher then the values for the fruit powder. The stem and fruit powders contained 19.30 mg/g and 25.10 mg/g of crude saponin, respectively. The pH of the stem and fruit powders was 5.34 and 5.07, respectively, both indicating low acidity. The L, a and b values of the stem powder color were 78.28, -3.71, and 19.19, respectively. The L, a and b values of the fruit powder color were 55.56, 24.84, and -3.18, respectively. The stems powder had a higher bulk density, water holding capacity, and swelling power than those of the fruit powder, but water-retaining capacity of the stem powder was lower than that of the fruit powder. In addition, the stems powder had a higher viscous material content and water uptake compared to the fruit powder. Based on the above results, we determined that Cheonnyuncho (Opuntia humifusa) powder had potentially useful functional components and physical properties.

• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.135-143
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• 2015

This study evaluated fuel properties of composite materials which were prepared by mixing a waste activated carbon from the used purifier filter with torrefied wood powder. Wood species of the raw material of torrefied wood powder are oak wood (Quercus serrata Thunb. ex Murray) and pine wood (Pinus densiflora Siebold & Zucc). And the treatment conditions used for this study were 300 s, 450 s, and 600 s at $200^{\circ}C$ for the wood roaster. Also, the mixing ratios are 5 : 95, 10 : 90, 15 : 85, 20 : 80, 40 : 60, 60 : 40 and 80 : 20 (waste activated carbon : torrefied wood powder). The fuel properties such as highly heating value (HHV), elementary analysis and ash content were evaluated. The results obtained are followings; 1. Despite the same treatment condition of wood roasting, pine wood has higher carbon contents than oak wood. Therefore, pine wood indicated the optimum carbonization at low temperature and short treatment times. 2. The gross calorific value and ash content increased as the mixing ratio of waste activated carbon increased. 3. Mixtures of the waste activated carbon and torrefied wood powder showed greater gross calorific value than those of the mixtures of waste activated carbon and the untreated wood powder. Also, the pine wood resulted in higher heating value that thaose of the oak wood. 4. When composite fuels that were composed waste activate carbon and wood powder are used, higher temperature conditions are required because the combustion is incomplete at $800^{\circ}C$ and 4 hours. 5. The increasing rate of the gross calorific value of mixtures of waste activated carbon and untreated wood powder is higher than does the mixtures of waste activated carbon and torrefied wood powder. Also, this phenomenon is more obvious for pine woods. Therefore, an optimal mixing ratio of waste activated carbon was determined to be between 5% and 10% (wt%). Also, this condition satisfied the requirement of the No.1 grade of wood pellet.