• Journal of Environmental Science International
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• v.16 no.10
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• pp.1203-1208
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• 2007

Feathers are produced in huge quantities as a waste product at commercial poultry processing plants. Since feathers are almost pure keratin protein, feather wastes represent an alternative to more expensive dietary ingredients for animal feedstuffs. Generally they become feather meal used as animal feed after undergoing physical and chemical treatments. These processes require significant energy and also cause environmental pollutions. Therefore, biodegradation of feather by microorganisms represents an alternative method to prevent environment contamination. The aim of this study was to investigate cultural conditions affecting keratinolytic protease production by Bacillus pumilus RS7. We also assessed the nutritive value of microbial and alkaline feather hydrolysates, The composition of optimal medium for the keratinolytic protease was fructose 0.05%, yeast extract 0.3%, NaCl 0.05%, K2HPO4 0.03%, KH2PO4 0.04% and MgCl2 6H2O 0.01%, respectively. The optimal temperature and initial pH was $30^{\circ}C$ and 9.0, respectively. The keratinolytic protease production under optimal condition reached a maximum after 18 h of cultivation. Total amino acid content of feather hydrolysates treated by NaOH and B. pumilius RS7 was $113.8\;{\mu}g/ml$ and $504.9\;{\mu}g/ml$, respectively. Essential amino acid content of feather hydrolysates treated by NaOH and B. pumilius RS7 was $47.2\;{\mu}g/ml$ and $334.0\;{\mu}g/ml$, respectively. Thus, feather hydrolysates have the potential for utilization as an ingredient in animal feed.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.641-649
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• 2011

This study was to analyze the soil environmental characteristics and vegetation status of green roof in Daejeon Metropolitan City. The investigated floras of vascular plants are 17 families, 26 genera, 28 species in Seo-Gu Daejeon District Office Building (SG), 25 families, 49 genera, 56 species in Galma Public Library (GP), and 34 families, 57 genera, 60 species in Daejeon City Hall (DC) respectively. Although the larger area shows the more numbers of species in introduced plants and naturalized plant, the naturalized plant ratios were similar with each other. They were 10.71%, 10.71%, and 11.67% at SG, GP, and DC respectively. As a result of analysis on soil physical property, soil depths including vegetation soil and drainage soil of 3 green roofs were 30cm. The depths of vegetation soil at SG, GP, and DC were 0~8cm, 0~10cm, 0~10cm respectively. As a results of soil chemical properties of our study, soil pH of vegetation soil and drainage soil were a range of 6.42 and 7.43, and a range of 6.55 and 7.43 on the average respectively. Available-P contents of vegetation soil and drainage soil were a range of 153.33 and 366.33mg/kg, and a range of 136.67 and 242.67 mg/kg which is very high, respectively. Carbon contents in soil at vegetation soil and drainage soil were a range of 3.16 and 6.38%, and a range of 1.63 and 2.47% respectively. Carbon storage per square meter within 30 cm were 2.76 kg, 2.99 kg, and 3.66 kg at SG, GP, and DC respectively.

• Journal of Aquaculture
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• v.17 no.4
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• pp.268-274
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• 2004

Olive flounder was treated with oxytetracycline (OTC) and changes in blood physiology, antioxidant enzymes and heat shock protein (HSP) were recorded to obtain preliminary data for optimal OTC treatment. Blood parameters were measured 1 and 3 h after the OTC treatments at the concentration of 0 (control), 100, 300 and 500 ppm for I h. Hematocrit decreased with time, however the difference was not significant (P>0.05). Reduced number of red blood cell was observed with increasing OTC concentration. Serum glucose level increased as the OTC concentration increased. However, glucose level was similar to control after 3 h. Blood total protein decreased immediately after the OTC treatment but increased after 1 and 3 h. However, the increment in blood total protein was low. Activities of superoxide dismutase enzymes in 300 and 500 ppm groups increased by the OTC concentration. Catalase enzyme activity was negatively affected by the OTC concentration. However, the differences were not significant (P>0.05). High expression of HSP-70 protein was recorded for groups treated with 100 and 500 ppm compared to that of the control group. However HSP-70 mRNA showed a lower increment which was not significant (P>0.05).

• Polymer(Korea)
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• v.36 no.2
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• pp.124-130
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• 2012

The uniform nanofibers of poly(L-lactide-$co$-${\varepsilon}$-caprolactone) (PLCL) with different contents of marine collagen (MC) were successfully prepared by electrospinning method. The effects of the major parameters in electrospinning process such as tip to target distance (TTD), voltage, nozzle size and flow rate on the average diameter of the electrospun nanofiber were investigated in generating composite nanofiber. The diameter and morphology of the nanofibers were confirmed by a scanning electron microscopy (SEM). Also, we measured a water contact angle to determine the surface wettability of the nanofibers. The average diameter of the nanofibers decreased as the value of TTD, MC contents, and voltages increased in comparison with that of pristine PLCL nanofiber. In contrast, the diameter of the nanofibers increased as the flow rate and inner diameter of nozzle increased in comparison with that of pristine PLCL. In addition, the hydrophilicity of the nanofiber and attachment of MG-63 cells on the sheets increased as incorporated collagen contents increased. Therefore, the marine collagen would be a potential material to enhance cellular interactivity of synthetic materials by mimicking the natural tissue.

• Polymer(Korea)
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• v.33 no.6
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• pp.551-554
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• 2009

Poly (vinyl alcohol) (PVA) and carboxymethyl cellulose (CMC) have received increasing attention in biomedical and biochemical applications because of their properties such as being water-soluble and biocompatible. In this study, a PVA/CMC hydrogel applicable to artificial cartilage was prepared by a freezing-thawing technique and a gamma-ray irradiation. The solid concentration of PVA was 7 wt% and the concentration of CMC was 4 wt%. The freezing/thawing process was repeated twice and the dose of gamma-ray irradiated was 30 kGy. Results of gelation before and after gamma-ray irradiation were similar, but the swelling degree decreased and compressive strength increased. The cytotoxicity was investigated with CCK-8 assay.

• Journal of Environmental Health Sciences
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• v.44 no.1
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• pp.1-14
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• 2018

Objectives: The purpose of this study is to investigate the main cause of visibility impairment by analyzing the contributions of the light extinction coefficient of major air pollution components and the change of the light extinction coefficient by relative humidity. Methods: The characteristics of the light extinction coefficient calculated by the photochemical method using fine particle component data measured in 2015 in the Gwangju area were examined. Results: The extinction efficiency per unit mass of $PM_{2.5}$ particles was $4.5m^2/g$ and that of $PM_{10-2.5}$ particles was $0.6m^2/g$. This difference indicates that most of the visibility impairment in Gwangju was caused by $PM_{2.5}$ particles. When visibility was poor, the contribution of ammonium sulphate and ammonium nitrate was significantly increased. Relative humidity was also a major cause of visibility decay. The influx of air currents in Gwangju was mostly caused by the long distance movement of pollutants emitted from the eastern part of China. Ammonium sulphate and ammonium nitrate, which are hygroscopic secondary contaminants, were the main causative agents of visibility impairment. Conclusions: Ammonium sulphate and ammonium nitrate were the main causative agents of visibility impairment in Gwangju. The influx of air currents in Gwangju was mostly caused by the long distance movement of pollutants emitted from the eastern part of China.

• Korean Journal of Food Science and Technology
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• v.46 no.4
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• pp.432-437
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• 2014

This study was carried out to examine the quality properties of honey in Korean commercial markets. The moisture content, stable carbon isotope ratio, invert sugar, cane sugar, and hydroxy-methylfurfural (HMF) contents of honey were measured according to the Korea Food Code and AOAC's (Association of Official Analytical Chemists) official methods. The stable carbon isotope ratio ranged from -25.18‰ to -12.60‰, which clearly differed between honey of $C_3$ origin (flower) and $C_4$ origin (artificial). Results of quality measurements revealed a moisture content of 18.12 to 19.70%, fructose content of 36.10 to 43.94%, glucose content of 22.61 to 31.91%, sucrose content of 1.56 to 4.75%, invert sugar content of 64.89 to 72.79%, and HMF content of 4.10 to 78.66 mg/kg. These values demonstrate that the quality of the tested honey meets the standard criteria of the Korean Food Code and Codex. However, it is necessary to reconsider the appropriate criteria for imported honey because it is circulated in the market through a long distribution process.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.5
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• pp.711-720
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• 2009

Leaf fibers have many good properties; they are strong, long, cheap, abundant and bio-degradable. Since they, however, contain a great quantity of non-cellulose components, they have been used for the materials of mats, ropes, bags and nets rather than those of clothing. In this study, we investigated the characteristics of leaf fibers in order to promote the use of leaf fibers for the materials of clothing as well as develop the high value-added textile fibers. Leaf fiber plants including New Zealand Flax, Henequen and Banana plant, which have various nature and shape, were used. New Zealand Flax and Henequen leaves were cut from lower part of plants. Banana leaves and pseudo-stems were peeled and cut from the stem of Banana plants. First, the thin outer skins like film of leaves, veins and stems were removed before retting. The chemical retting had been processed for 1hour, at 100 in 0.4% $H_2SO_4$ aqueous solution(liquid ratio 50:1). Then, the retted leaf fibers had been soaked for 1hour, at room temperature in 0.5% NaClO solution(v/v) to remove the miscellaneous materials. We investigated the physical characteristics of three leaf fibers including the transversal and longitudinal morphology, the contents(%) of pectin, lignin and hemicellulose, the length and diameter of fibers, the tensile strength of the fiber bundles, and the fiber crystallinity and the moisture regain(%). The lengths of fiber from three leaf fibers were similar to their leaf lengths. The fiber bundles were composed of the cellulose paralleled to the fiber axis and the non-cellulose intersecting at right angle with the fiber axis. The diameters of New Zealand Flax, Henequen and Banana fibers were $25.13{\mu}m$, $18.16{\mu}m$ and $14.01{\mu}m$, respectively and their tensile strengths were 19.40 Mpa, 32.16 Mpa and 8.45 Mpa, respective. The non-cellulose contents of three leaf fibers were relatively as high as 40%. If the non-cellulose contents of leaf fibers might be controlled, leaf fibers could be used for the materials of textile fiber, non-wovens and Korean traditional paper, Hanjee.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.8
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• pp.780-786
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• 2010

The bacterial community structure in biological reactor in wastewater treatment system was investigated by denaturing gradient gel electrophoresis (DGGE) and fluorescent in situ hybridization (FISH). Samples were collected at different three points in wastewater treatment system. Through treatment processes, BOD (biochemical oxygen demand) and COD (chemical oxygen demand) of was removal efficiency was 83.1~98.6%, 67.2~85.2% respectively. Microbial community of aerobic tank and oxic tank were similar but anoxic tank was different (RRP group was increased about tripple) by DGGE and FISH in sludge (2007 October and 2008 January). Samples in 2007 October and 2008 January were dominant ${\alpha}$-Proteobacteria and CF group respectively. Sludge in 2008 April were different comparing former results dominant others as 65~80%. Others group was dominant. Eubacteria by FISH with the probe EUB338 was about $1.7{\sim}7.6{\times}10^9\;cells/mL$. It could be successfully observed bacterial community in biological wastewater system.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.1
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• pp.42-45
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• 2014

Even though to discard the waste FRP (Fiber-Reinforced Plastic) is urgent and problematic, the way to do it has not been efficient. In our project team the FRP have been splitted into some layers which have different physical properties; mat and roving layers. Among those, the roving layer woven like a basket by bundles of glass fibers has been cut into reusable fibers called 'F-fiber'. F-fiber is 1 mm or 3 mm in width and 3 cm in length. It is used in fiber-reinforced concrete (FRC) with 0.5%, 0.7%, 1.0%, or 1.5% of volume ratio. Produced FRC was tested in compressive, tensile, and bending stress in contrast to the without-fiber (standard) concrete and 0.1% polypropylene reinforced concrete (PP-FRC). The tensile and bending stresses are more or less those of PP-FRC. The compressive stress, however, is similar (with 3 mm F-fiber) to or lower (with 1 mm F-fiber) than that of standard concrete. Conclusively the usage of the waste FRC in concrete is advised to be limited to the one where the compressive stress is not much critical.