• Journal of Life Science
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• v.15 no.2 s.69
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• pp.231-235
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• 2005

Matrix metalloproteinases (MMPs) are a family of structurally and functionally related zinc-dependent enzymes responsible for proteolytic degradation of extracellular matrix components such as base membrane or interstitial stroma. MMPs play an important role in a variety of physiological and pathological tissue remodeling processes, including wound healing, embryo implantation, tumor invasion and metastasis. Since MMP-9 (gelatinase B) has unique ability to cleave type IV collagen, gene expression of MMP-9 has been focused on as a pharmacological target. Flavonoids are a class of compounds that are widely spread in plants. In the coures of screening for the suppressors of MMP-9 gene expression from natural products, Metasequoia glyptostroboides was selected. Six flavonoids, sciadopitysin, isoginkgetin, bilobetin, 2,3-dihydrohinokiflavone, luteolin and apigenin were purified as suppressors of MMP-9 gene expression from M. glyptostroboides. The suppressing activity of the isolated flavinoids on the MMP-9 gene expression was measured by gelatin zymography and Nothern blot analysis.

• Journal of Soil and Groundwater Environment
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• v.15 no.3
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• pp.15-26
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• 2010

The contaminated soils near abandoned mine area can threaten human's health and natural ecosystems through multiple pathways. Remediation of contaminated soil using physicochemical technologies are expensive and destructive of soil environments. On the other hand, environmentally friendly approach that maximize biological remediation, that is, phytoremediation, attracts attention as a low carbon green growth technology. This research is a field demonstration study, focused on the enhanced phytoremediation by bioaugmenting PGPR(Plant Growth Promoting Rhizobacteria)that is helpful on the growth of and heavy metal removal by Echinochloa frumentacea, at a Zn contaminated paddy soil near SamBo mine at Hwasung, Kyunggi. The results showed that the zinc removal by the plant with PSM(Phosphate Solubilizing Bacteria), a kind of PGPR, was three times higher than that by the control. The results are valuable as it is a result from the field-scale technology demonstration. The results also implies that application of PGPR can enhance heavy metal removal from contaminated soil in full scale phytoremediation using Echinochloa frumentacea.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.23-23
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• 2018

In this study, new titanium alloys were prepared by adding elements such as tantalum (Ta), zirconium (Zr) and the like to complement the biological, chemical and mechanical properties of titanium alloys. The Ti-40Ta-xZr ternary alloy was formed on the basis of Ti-40Ta alloy with the contents of Zr in the contents of 0, 3, 7 and 15 wt. %. Plasma electrolytic oxidation (PEO), which combines high-voltage sparks and electrochemical oxidation, is a novel method to form ceramic coatings on light metals such as Ti and its alloys. These oxide film produced by the electrochemical surface treatment is a thick and uniform porous form. It is also composed of hydroxyapatite and calcium phosphate-based phases, so it has the characteristics of bone inorganic, non-toxic and very high bioactivity and biocompatibility. Ti-40Ta-xZr alloys were homogenized in an Ar atmosphere at $1050^{\circ}C$ for 1 hour and then quenched in ice water. The electrochemical oxide film was applied by using a power supply of 280 V for 3 minutes in 0.15 M calcium acetate monohydrate ($Ca(CH_3COO)_2{\cdot}H_2O$) and 0.02 M calcium glycerophosphate ($C_3H_7CaO_6P$) electrolyte. A small amount of 0.0075M zinc acetate and magnesium acetate were added to the electrolyte to enhance the bioactivity. The mechanical properties of the coated surface of Ti-40Ta-xZr alloys were evaluated by Vickers hardness, roughness test, and elastic modulus using nano-indentation, and the surface wettability was evaluated by measuring the contact angle of the coated surface. In addition, cell activation and differentiation were examined by cell culture of HEK 293 (Human embryonic kidney 293) cell proliferation. Surface properties of the alloys were analyzed by scanning electron microscopy(FE-SEM), EDS, and X-ray diffraction analysis (XRD).

• The Journal of Natural Sciences
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• v.19 no.1
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• pp.65-75
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• 2008

This research was conducted to determine heavy metal contents of soil and tree in pear orchard located near national road with heavy traffics. Topsoil (0-15 cm depth) and subsoil (15-30 cm) samples in pear orchard located within 40 m from national road had higher Pb, Cu, and Zn contents than background orchard (BG) and these heavy metal contents decreased with distance from road. Topsoil samples taken at 10 m from national road had 4 times higher level in Pb, 3 times in Cu, and 2.5 times in Zn compare to BG. The Cd contents of topsoil in orchard were higher than those of BG but were not in subsoil. Highest heavy metal contents of pear leaves in roadside orchard were 20.08 in Pb, 7.02 in Cu, 30.83 in Zn, and $1.68\;mm.kg^{-1}$ in Cd and these heavy metal contents in roadside orchard were higher than BG. Cd contents of fruit and Pb contents of fruit stalk in roadside orchard were higher than BG and these heavy metal contents decreased with distance up to 40 m from the road.

• Korean Journal of Veterinary Service
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• v.29 no.4
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• pp.459-467
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• 2006

This study was designed to investigate if there were groundwater contamination in 17 landfill where slaughtered animals were buried during the crisis of 2002 foot-and-mouth-disease (FMD) outbreaks in Gyeonggi province. From March to August 2005 groundwater was collected once a month from 17 sites, and examined with potential for hydrogen (pH), colour, turbidity, lead (Pb), arsenic (As), mercury (Hg), cadmium (Cd), copper (Cu), zinc (Zn) , iron (Fe), manganese (Mn) , aluminium (Al), nitrate-nitrogen $(NO_3-N)$, ammonia-nitrogen $(NH_3-N)$, microbial pathogen and Escherichia spp. In the examination of $NH_3-N$ which of the mean concentration was from not-detected (ND) to 0.05 mg/l. The range of $NH_3-N$ level was $0.3-24.1mg/{\ell}$. However, groundwater from four sites was to go beyond the drinking water quality standard (DWQS), i.e., the mean concentration of those were $15.5mg/{\ell}\;(site\;1),\;20.7mg/{\ell}\;(site\;9),\;24.1mg/{\ell}\;(site\;13)\;and\;10.6mg/{\ell}\;(site\;17)$. In the investigation of pH, colour and turbidity, all of the pH were below of DWQS (pH 5.8-6.6), but one site in color test and four sites in turbidity test were over the standard level. Among 9 metal ions examined, Mn was in excess of DWQS, and its concentration was $2.4mg/{\ell}$. Pb, Cd, Hg and As were not traced. The contents of Cu, Zn, Fe and Al were $ND-0.22mg/{\ell},\;0.01-0.05mg/{\ell},\;ND-0.05mg/{\ell}\;and\;0.03-0.16mg/{\ell}$, respectively. Escherichiae spp were not identified, but bacterial colonies were detected at 3 groundwater including 2 sites over the DWQS at the level of $491CFU/m{\ell}\;(site\;4)\;and\;217CFU/m{\ell}\;(site\;15)$.

• Korean Journal of Community Nutrition
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• v.15 no.4
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• pp.485-497
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• 2010

The purpose of this study was to investigate effects of the developed nutrition education program focused on individual daily energy requirements and food exchange units using Food Exchange System for diabetes mellitus at a community health center. Developed the nutrition education program, four weeks' nutrition education including provided twice individual meal as diet therapy (2 hour/lesson/week, 4 week), was provided to 20 diabetic elderly (12 male, 8 female, 50-75 yrs): 1st lesson "Introduction: management of diabetes mellitus", 2nd lesson "6 Food groups and sources of 6 food groups", 3rd lesson "Individual daily energy requirements and food exchange units", and 4th lesson "Food choice for diabetes mellitus". For effects' analysis of the developed program, we assessed the changes in anthropometric characteristics; biochemical characteristics and nutrient intakes using 24 hr recall method. Effects of the developed nutrition education program were as follows: weight was significantly decreased, blood urea nitrogen (BUN) and glycosylated hemoglobin (HbA1c) were significantly decreased, and distribution of subjects in BUN and HbA1c was significantly changed. In protein : fat : carbohydrate (PFC) ratio, it was significantly changed from 15.98 : 16.30 : 66.69 to 17.51 : 18.94 : 64.10. In evaluation of nutrient intakes by Dietary Reference Intakes for Koreans (KDRI), protein, fiber, fat, vitamin E, niacin, folic acid, calcium and zinc were shown significantly positive changes in distribution of subjects according to intake level. The index of nutrition quality (INQ), nutrition adequacy ratio (NAR) and mean nutrition adequacy ratio (MAR) were significantly increased. In conclusion, the developed 4 weeks' nutrition education program focused on individual daily energy requirements and food exchange units using Food Exchange System for diabetes mellitus at community health center may improve the symptom of diabetes mellitus.

• Applied Biological Chemistry
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• v.32 no.3
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• pp.232-239
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• 1989

Three types of Korean strawberries, Gardian cultivated in vinyl house, Gardian cultivated on the field and Bogyo, at early variety, on the field were harvested after $10{\sim}34$ days from falling of flowers to investigate the chemical changes of fruits during maturing. The initial pH range after 10 days from falling of flowers was $4.13{\sim}4.28$, which was decreased to $3.40{\sim}3.49$ with maturing. The total acid was steadily increased for 26 days and then decreased thereafter. Vitamin C, not detected until 14 days, was gradually increased to $15.83{\sim}24.90mg%$ in 34 days. Reducing sugar content was increased for 24 days and then decreased, while total sugar, glucose and fructose were generally increased during maturing. Xylose was detected a little. For minerals, potassium was measured the highest value, followed by magnessium, and sodium. A trace amount of manganese, zinc and copper were detected. The strawberries had the content range of $6.00{\sim}24.60mg%$ of methyl alcohol and $6.00{\sim}24.40mg%$ of ethyl alcohol.

• Resources Recycling
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• v.26 no.5
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• pp.48-53
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• 2017

During steelmaking on EAF, 1 ~ 2% of dust is generated. EAF Dust contains 20 ~ 30% of Zn and Fe. Dust contained in Off-gas is passed through combustion tower and cooling tower, and then captured in bag filter. About 15 wt.% of dust is dropped at the bottom of Combustion tower by its specific gravity, which was also carried out to recycle company with more higher charge than Bag filter dust. This study is focused on the combustion tower dust, and seperation as a function of operation period and particle size. As a result, Zn and Fe content of dust is more affected by size factor than operation period.

• Resources Recycling
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• v.33 no.1
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• pp.15-21
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• 2024

The demand for electric vehicles powered by lithium-ion batteries is continuously increasing. Recovery of valuable metals from waste lithium-ion batteries will be necessary in the future. This research investigated the effect of reaction temperature on the lithium recovery ratio from hydrogen reduction followed by water leaching from lithium-ion battery NCM-based cathode materials. As the reaction temperature increased, the weight loss ratio observed after initiation increased rapidly owing to hydrogen reduction of NiO and CoO; at the same time, the H₂O amount generated increased. Above 602 ℃, the anode materials Ni and Co were reduced and existed in the metallic phases. As the hydrogen reduction temperature was increased, the Li recovery ratio also increased; at 704 ℃ and above, the Li recovery ratio reached a maximum of approximately 92%. Therefore, it is expected that Li can be selectively recovered by hydrogen reduction as a waste lithium-ion battery pretreatment, and the residue can be reprocessed to efficiently separate and recover valuable metals.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.741-748
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• 2021

In this study, we evaluated image quality by changing collimator length and detector thickness using the Geant4 Application for Tomographic Emission (GATE) simulation tool. The gamma camera based on the Cadimium Zinc Telluride (CZT) and NaI detectors is modeled. In addition the images were acquired by setting 1, 2, 3, 4, 5, and 6 cm collimator length and 1, 3, 5, and 7 mm detector thickness using point source and phantom, which is designed by each diameter (4.45, 3.80, 3.15, 2.55 mm) with 447, 382, 317, and 256 Bq. The sensitivity (cps/MBq) for point source, and signal to noise ratio (SNR) and profile for phantom at the 4.45 mm by drwan the region of interests were used for quantitative analysis. Based on the results, the sensitivity according to collimator length is 2.3 ~ 48.6 cps/MBq for CZT detector, and 1.8 ~ 43.9 cps/MBq for NaI detector. The SNR using phantom is 3.6~9.8 for CZT detector, and 2.9~9.5 for NaI detector. As the collimator length is increased, the image resolution is also improved according to profile results based on the CZT and NaI detector. In addition, the senistivity for detector thickness is 0.04 ~ 0.12 cps/MBq for CZT detector, and 0.03 ~ 0.11 cps/MBq. The SNR using phnatom is 7.3~9.8 count for CZT detector, and 5.9~9.5 for NaI detector. As the detector thickness is increased, the image resolution is decreased according to profile results based on the CZT and NaI detector due to scatter ray. In conclusion, we need to set the geometric material such as detector and collimator to acuquire suitable image quality in nuclear medicine.