• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.5
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• pp.263-269
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• 2017

A piezoelectric cantilever energy harvester (PCEH) driven in longitudinal (3-3) vibration mode was fabricated, and its electrical properties were evaluated by varying the resistive load. A commercial PZT piezoelectric ceramic with a high piezoelectric charge constant ($d_{33}$) of 520 pC/N and the interdigitated (IDT) electrode pattern was used to fabricate the PCEH driven in longitudinal vibration. The IDT Ag electrode embedded piezoelectric laminates were co-fired at $850^{\circ}C$ for 2 h. The 3-3 mode PCEH was successfully fabricated by attaching the piezoelectric laminates to a SUS304 elastic substrate. The PCEH exhibited a high output power of 3.8 mW across the resistive load of $100k{\Omega}$ at 100 Hz and 1.5 G. This corresponds to a power density of $10.3mW/cm^3$ and a normalized global power factor of $4.56mW/g^2{\cdot}cm^3$. Given the other PCEH driven in transverse (3-1) vibration mode, the 3-3 mode PCEH could be better for vibration energy harvesting applications.

• Economic and Environmental Geology
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• v.44 no.6
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• pp.485-492
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• 2011

Sorption of cyanide on granular activated carbon and attenuation of the cyanide by UV-light over a wide range of conditions such as pH and concentration were investigated through batch experiments. Cyanide uptake by activated carbon is much effective at $[CN]_{ini}$ < 2 mg/L. The sorption of cyanide on activated carbon at pH 7.0 is greater than that of pH 9.0. It is found that the ratio of CN uptake to CN in solution increases at pH 9.0 whereas at pH 7.0 the ratio decreases, suggesting that reactivity of activated carbon increases as a function of pH. The sorption of cyanide rapidly increases during the first 30 min, followed by sharp desorption until 3hr, and then the sorption increases and reaches the maximum sorption during the duration of experiments, implying that the sorption mode could be changed through conformational change during the initial stage of the cyanide uptake by activated carbon. Total amount of cyanide desorbed from the activated carbon during the period of desorption experiments is less than 1.5% of total sorbed cyanide, indicative of strong and stable sorption of cyanide on the activated carbon. The sorption with mixture of activated carbon and Ham-Baek sludge shows less effective on the removal of the cyanide. It is noted that UV-light is much effective on the removal of cyanide but also the attenuation is achieved until $[CN]_{tot}$ is up to 10 mg/L. Our findings demonstrate that both activated carbon and UV-light are very effective on the attenuation of cyanide over a wide range of environmental conditions.

• Journal of Aquaculture
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• v.18 no.3
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• pp.135-141
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• 2005

A 16-week feeding trial was conducted to estimate the optimum dietary protein to energy ratio (P/E ratio, mg/kcal) in juvenile Japanese eel, Anguilla japonica. Six experimental diets were formulated with three energy levels and two protein levels at each energy level. Three energy levels of 3800, 4150 and 4500 kcal per kg diets were included at 45 and 50% crude protein (CP) levels, respectively $(_{120}P_{45},\;_{110}P_{45},\;_{100}P_{45},\;_{130}P_{50},\;_{120}P_{50},\;and\;_{110}P_{50})$. After four weeks of the conditioning period, fish initially averaging $15.0{\pm}3g\;(means{\pm}SD)$ were randomly distributed into each tank as groups of 20 fish. Each diet was fed to fish in three randomly selected tanks at a rate of $2{\sim}3%$ wet body weight per day in the recirculated system. Weight gain (WG) and specific growth rate of fish fed diet $_{100}P_{45}$ were significantly higher (P<0.05) than those of fish fed the other diets. WG of fish fed diet $_{120}P_{50}$ was also significantly higher than those of fish fed diets $_{130}P_{50}$ and $_{110}P_{50}$. Feed efficiency ratio of fish fed diets $_{100}P_{45}$ and $_{110}P_{45}$ were significantly higher (P<0.05) than those of fish fed other diets. These results suggest that the optimum P/E ratio may be 100 mg/kcal with 45% protein diets, and 120 mg/Kcal 50% protein diets for the maximum growth of juvenile Japanese eel under the experimental condition.

• Journal of Nutrition and Health
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• v.53 no.4
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• pp.390-405
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• 2020

Purpose: The effect of prebiotics intake after administration of a synbiotics mixture (a probiotic, Bifidobacterium longum, and a prebiotic, xylooligosaccharide containing sugar [XOS]) on human intestinal microflora and defecation characteristics was investigated in a randomized controlled trial. Methods: Twenty-five healthy young volunteers (11 males and 14 females) were randomly assigned to 2 groups (BL2XO2 and BL2XO6). The synbiotics mixture was orally administered to both groups for 2 weeks, and the prebiotics were subsequently administered to the BL2XO6 group for 4 additional weeks. The daily dose of the synbiotics mixture comprised 10¹⁰ colony-forming unit of Bifidobacterium longum and 10 g of XOS, and during the prebiotics period, the daily dose of prebiotics comprised only 10 g of XOS. The fecal pH, microflora, and defecation characteristics were analyzed at baseline and at weeks 1, 2, 4, and 6. Results: The counts of B. longum and Bifidobacterium spp. in the BL2XO6 group exhibited a steady, increasing trend during the synbiotics and prebiotics periods, whereas those of the BL2XO2 group exhibited considerable variation in each week of the study period. Although there was no significant difference, the counts of fecal Bifidobacterium in the BL2XO6 group tended to be higher than those of the BL2XO2 group at week 6. The growth of Lactobacillus spp. exhibited a time-dependent variation, peaking at week 6 in both groups. Low counts of Clostridium spp. were observed after treatment with the synbiotics and prebiotics in the BL2XO6 group (p < 0.05) throughout the study, whereas the inhibitory effect on Clostridium spp. was maintained only during the synbiotics period in the BL2XO2 group. The defecation characteristics did not differ between the two groups. Conclusion: Administration of XOS after a synbiotics mixture containing B. longum and XOS can exert a prebiotic effect in healthy young volunteers by stimulating Bifidobacteriun spp. growth and inhibiting growth of Clostridium spp.

• Journal of Korea Water Resources Association
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• v.33 no.5
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• pp.551-559
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• 2000

In order to diagnose the water environment and assess the water quality restoration, long term trend of water environment has been surveyed at 3-R stations from 1994 to 1999 in Lake Shihwa. Annual mean values of $COD_{Mn}$, Chlorophyll a, total nitrogen, total phosphorus and Secchi depth are ranged in 5.2-15.1 mg/L, 7.3-14R.1 jlg/L, 1.50-4.84 mgN/L, 0.055-0.281 mgP/L and 0.5 -1.4 m, respectively, during the study periods. Carson's trophic state indeies were varied from mesotrophy in 1994 and 1995, hyper-eutrophy in 1996 and 1997, to meso eutrophy in 199R and 1999. After dike construction, water quality were rapidly deteriorated by allochthonous and autochthonous loading of high nutrients and organic carbon. Eutrophication phenomena were characterized by massive phytoplankton blooms and high concentration of COD. However, after onset of restoration program, lake water quality was rapidly restored to the level of just after sea-dike construction. The diversion of waste water inflowing from the Panwol and the Sihwa industrial districts which was started from March, 1997 has contributed to improve water quality in the surface layer. And the tidal mixing (sea water inflowing) through the continuous gate operation was the most effective measure to the whole lake restoration.ration.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.7
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• pp.377-386
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• 2016

The purposes of this research are to examine soil pollution in the nation and to explore the contaminated soil management of the public housing agency in public land for residential development. In so doing, the primary and secondary data were utilized, the former made use of the public data annually released by the Korea Ministry of Environment, and the latter relied on a self-administerd questionnaire survey conducted in the staff of the public housing agency, particularly those in charge of soil contamination in large-scale land, housing and urban development projects. The findings reveal that the national concentrations of 21 inorganic and organic soil contaminants (e.g., Cd, Cu, As, Hg, Pb, Cr, Zn, Ni, F, P, PCB, CN, Phenol, BTEX, TPH, TCE, PCE, Benzo(a)pyrene, and pH) in the land were extracted to be well below the risk level designated by the statutory guidance while industrial areas had them at a relatively modest level. In addition, the survey results indicate that the public housing agency didn't establish specific and clear guidelines for soil pollution and its remediation in the residential land development, so that contaminated sites have been primarily remediated by outsourcing companies. As the unexpected occurrence of contaminated sites causes the incurring expenses added to total project budget, the provision of both professional training and on-site manuals with the sufficient information on techniques and methods of soil contamination is critical to promptly and systematically deal with soil pollution.

• Economic and Environmental Geology
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• v.46 no.4
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• pp.329-338
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• 2013

The objective of this study is to investigate the contents and seasonal variation of arsenic in soils and crop plant(rice) in paddy fields around the abandoned metal mines in Korea. The soils were extracted by various methods including aqua regia, 1 M $MgCl_2$, 0.01 M $CaCl_2$ and 0.05 M EDTA to evaluate the relationships between soils and crop plants(rice). According to correlation analysis, statistically significant correlation with the four methods(p<0.01) were found in soils extracted by various chemical solutions and arsenic contents in soils were decreased in the order of 1M $MgCl_2$ > 0.01M $CaCl_2$ > 0.05 M EDTA. Biological accumulation coefficients(BACs) of rice stalks were higher than those of rice grain, and the coefficients under reducing(August) environment were higher than those under oxidizing conditions(October). Assuming the rice consumption of 315 g/day by farm households in Korea, the amount of daily intake of arsenic were estimated to be 77.8 ${\mu}g/day$. The daily intake of arsenic from the rice estimates up to 65% of ADI(acceptable daily intake) that the FAO/WHO Joint Food Additive and Contaminants Committee has set to evaluate their safeties.

• Journal of Microbiology and Biotechnology
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• v.29 no.11
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• pp.1693-1706
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• 2019

Atopic dermatitis (AD) is a chronic inflammatory skin disease of mainly infants and children. Currently, the development of safe and effective treatments for AD is urgently required. The present study was conducted to investigate the immunomodulatory effects of yeast-extracted β-1,3/1,6-glucan and/or Lactobacillus plantarum (L. plantarum) LM1004 against AD-like symptoms. To purpose, β-1,3/1,6-glucan and/or L. plantarum LM1004 were orally administered to AD-induced animal models of rat (histamine-induced vasodilation) and mouse (pruritus and contact dermatitis) exhibiting different symptoms of AD. We then investigated the treatment effects on AD-like symptoms, gene expression of immune-related factors, and gut microbiomes. Oral administration of β-1,3/1,6-glucan (0.01 g/kg initial body weight) and/or 2 × 10¹² cells/g L. plantarum LM1004 (0.01 g/kg initial body weight) to AD-induced animal models showed significantly reduced vasodilation in the rat model, and pruritus, edema, and serum histamine in the mouse models (p < 0.05). Interestingly, β-1,3/1,6-glucan and/or L. plantarum LM1004 significantly decreased the mRNA levels of Th2 and Th17 cell transcription factors, while the transcription factors of Th1 and Treg cells, galactin-9, filaggrin increased, which are indicative of enhanced immunomodulation (p < 0.05). Moreover, in rats with no AD induction, the same treatments significantly increased the relative abundance of phylum Bacteroidetes and the genus Bacteroides. Furthermore, bacterial taxa associated with butyrate production such as, Lachnospiraceae and Ruminococcaceae at family, and Roseburia at genus level were increased in the treated groups. These findings suggest that the dietary supplementation of β-1,3/1,6-glucan and/or L. plantarum LM1004 has a great potential for treatment of AD as well as obesity in humans through mechanisms that might involve modulation of host immune systems and gut microbiota.

• Journal of Environmental Health Sciences
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• v.48 no.6
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• pp.315-323
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• 2022

Background: Socioeconomical disadvantaged communities are more vulnerable to environmental chemical exposure and associated health effects. However, there is limited information on chemical exposure among vulnerable populations in Korea. Objectives: This study investigated chemical exposure among underprivileged populations. We measured urinary metabolites of phthalates in urban disadvantaged communities and investigated their correlations with residential environment factors and relative socioeconomic vulnerability. Methods: Urine samples were collected from 64 residents in a disadvantaged community in Seoul. A total of eight phthalate metabolites were analyzed by liquid chromatography-mass spectroscopy. Analytical method used by the Korean National Environmental Health Survey (KoNEHS) was employed. Covariate variance analysis and general linear regression adjusted with age, sex and smoking were performed. Results: Several phthalate metabolites, namely monomethyl phthalate (MMP), monoethyl phthalate (MEP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono-n-butyl phthalate (MnBP) had higher levels than those reported in the adults of 4th KoNEHS. Notably, the MnBP level was higher in the lower socioeconomic group (geometric mean [GM]=47.3 ㎍/g creatinine) compared to non-recipients (GM=31.9 ㎍/g creatinine) and the national reference level (GM=22.0, 28.2 and 32.2 ㎍/g creatinine for adults, 60's and 70's, respectively.). When age, sex and smoking were adjusted, MEP and MnBP were significantly increased the lower socioeconomic group than non-recipients (p=0.014, p=0.023). The lower socioeconomic group's age of flooring were higher than non-recipients, not statistically significant. Conclusions: These results suggest that a relatively low income and aged flooring could be considered as risk factors for increased levels of phthalate metabolites in socioeconomic vulnerable populations.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.62-62
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• 2020

Ginseng is a shade-plant cultivated using shading facilities. However, at too low light levels, root growth is poor, and at high light levels, the destruction of chlorophyll reduces the photosynthesis efficiency due to leaf burn and early fall leaves. The ginseng has a lightsaturation point of 12,000~15,000 lux when grown at 15 to 20℃ and 9,500 lux at 25℃. This study was conducted to select the optimal light intensity of 3-year-old ginseng grown in blue-white film plastic house. The seeds were planted in the blue-white film plastic house with different light receiving rate (March 17, 2020). Between April and September, the average air temperature in the house was 20.4-20.7℃. Average soil temperature was 18.3℃-18.5℃. The chemical properties of the test soil was as follows. The pH level was 7.0-7.4, EC was 0.5-0.6 dS/m, OM was at the levels of 33.6-37.7 g/kg, P₂O₅ was 513.0-590.8 mg/kg, slightly higher than the allowable 400 mg/kg. The amount of light intensity, illuminance, and solar radiation in the blue-white film house was increased as the light-receiving rate increased and the amount of light intensity was found to be 9-14% compared to the open field, 8-13% illuminance and 9-14% solar irradiation respectively. The photosynthesis rate was the lowest at 3.1 µmolCO²/m²/s in the 9% light blue-white plastic house and 4.2 and 4.0 µmolCO²/m²/s in the 12% and 14% light blue-white plastic house, respectively. These results generally indicate that the photosynthesis of plants increases with the amount of light, but the ginseng has a lower light saturation point at high temperatures, and the higher the amount of light, the lower the photosynthetic efficiency. The SPAD (chlorophyll content) value decreased as the increase of light-receiving rate, and was the highest at 32.7 in 9% light blue-white plastic house. Ginseng germination started on April 11 and took 13-15 days to germinate. The overall germination rate was 82.9-85.8%. The plant height and length of stem were long in the 9% light-receiving plastic house. The diameter of stem was thick in the 12-14% light-receiving plastic house. In the 12% and 14% light-receiving plastic house, the length and diameter of taproot was long and thick, so the fresh weight of root per plant was 20 g or more, which was heavier than 16.9 g of the 9% light-receiving plastic house. The disease incidence (Alternaria blight, Gray mold and Damping-off etc.) rate were 0.9-2.7%. The incidence of Sclerotinia rot disease was 7.5-8.4%, and root rot was 0-20.0%. The incidence ratio of rusty root ginseng was 34.4-38.7% level, which was an increase from the previous year's 15% level.