• Journal of Biomedical Engineering Research
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• v.25 no.1
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• pp.11-19
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• 2004

Stage 1 sleep provides important information regarding interpretation of nocturnal polysomnography, particularly sleep onset. It is a short transition period from wakeful consciousness to sleep. Lack of prominent sleep events characterizing stage 1 sleep is a major obstacle in automatic sleep stage scoring. In this study, we attempted to utilize simultaneous EEC and EOG processing and analyses to detect stage 1 sleep automatically. Relative powers of the alpha waves and the theta waves were calculated from spectral estimation. Either the relative power of alpha waves less than 50％ or the relative power of theta waves more than 23％ was regarded as stage 1 sleep. SEM (slow eye movement) was defined as the duration of both eye movement ranging from 1.5 to 4 seconds and regarded also as stage 1 sleep. If one of these three criteria was met, the epoch was regarded as stage 1 sleep. Results f ere compared to the manual rating results done by two polysomnography experts. Total of 169 epochs was analyzed. Agreement rate for stage 1 sleep between automatic detection and manual scoring was 79.3％ and Cohen's Kappa was 0.586 (p＜0.01). A significant portion (32％) of automatically detected stage 1 sleep included SEM. Generally, digitally-scored sleep s1aging shows the accuracy up to 70％. Considering potential difficulties in stage 1 sleep scoring, the accuracy of 79.3％ in this study seems to be robust enough. Simultaneous analysis of EOG provides differential value to the present study from previous oneswhich mainly depended on EEG analysis. The issue of close relationship between SEM and stage 1 sleep raised by Kinnariet at. remains to be a valid one in this study.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.193-200
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• 2010

This study evaluated treatability of soluble Mn(II) using multifunctional sand media simultaneously coated with iron and manganese. In the preparation of IMCS(Iron and Manganese Coated Sand), 0.05 M Mn(II) solution and Fe(III) solution was mixed with sand at pH 7. The mineral type of IMCS was identified as the mixture of ${\gamma}-MnO_2$, goethite and magnetite($F_{e3}O_4$). The contents of Mn and Fe coated onto sand were 826 and 1676 mg/kg, respectively. The $pH_{pzc}$ of IMCS was measured as 6.40. The removal of soluble Mn(II) using IMCS and oxidants such as NaOCl and $KMnO_4$ was investigated with variation of the solution pH, reaction time and Mn(II) concentration in a batch test. The removal of Mn(II) on IMCS was 34% at pH 7.4 and the removals of Mn(II) on IMCS in the presence of NaOCl(13.6 mg/L) at pH 7 and $KMnO_4$(4.8 mg/L) at pH 7.6 were 96% and 89%, respectively. The removal of Mn(II) using IMCS and oxidants followed a typical cationic type, showing a gradual increase of removal as the solution pH increased. The removal of Mn(II) was rapid in the first 6 hrs and then a constant removal was observed. The maximum removed amount of Mn(II) on IMCS-alone and IMCS in the presence of oxidants such as NaOCl(13.6 mg/L) and $KMnO_4$(4.8mg/L) were 833.3, 1428.6 and 1666.7 mg/kg, respectively. Mn(II) removal onto the IMCS in the presence of oxidants was well described by second-order reaction and Langmuir isotherm expression.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.1
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• pp.9-18
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• 2017

Arsenic (As) has been considered as the most toxic one among various hazardous materials and As contamination can be caused naturally and anthropogenically. Major forms of arsenic in groundwater are arsenite [(As(III)] and/or arsenate [(As(V)], depending on redox condition: arsenite and arsenate are predominant in reduced and oxidized environments, respectively. Because arsenite is much more toxic and mobile than arsenate, there have been a number of studies on the reduction of its toxicity through oxidation of As(III) to As(V). This study was initiated to develop photocatalytic oxidation process for treatment of groundwater contaminated with arsenite. The performance of two types of light sources (UV lamp and UV LED) was compared and the feasibility of goethite as a photocatalyst was evaluated. The highest removal efficiency of the process was achieved at a goethite dose of 0.05 g/L. Based on the comparison of oxidation efficiencies of arsenite between two light sources, the apparent performance of UV LED was inferior to that of UV lamp. However, when the results were appraised on the basis of their emitting UV irradiation, the higher performance was achieved by UV LED than by UV lamp. This study demonstrates that environmentally friendly process of goethite-catalytic photo-oxidation without any addition of foreign catalyst is feasible for the reduction of arsenite in groundwater containing naturally-occurring goethite. In addition, this study confirms that UV LED can be used in the photo-oxidation of arsenite as an alternative light source of UV lamp to remedy the drawbacks of UV lamp, such as long stabilization time, high electrical power consumption, short lifespan, and high heat output requiring large cooling facilities.

• Journal of Korean Society of Forest Science
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• v.85 no.4
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• pp.634-646
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• 1996

This study was carried out to reveal the forest land effect on water purification in mountainous watersheds. Rainfall, throughfall, stemflow, soil and stream water were monitored by pH, electrical conductivity(EC), and dissolved oxygen(DO) in Daehan-Ri and Parkdal-Ri catchments. The results were summarized as follows; 1. Rainfall pH values of Parkdal-Ri and Daehan-Ri were 7.6 and 6.4, respectively. 2. Comparing stemflow and throughfall of Pinus densiflora with Pinus rigida, the pH values of Pinus densiflora were 4.32 and 4.22 and the pH of Pinus rigida were 3.34 and 4.81, respectively. The EC values of Pinus densiflora were $119.7{\mu}S/cm$ and $96.8{\mu}S/cm$ and EC of Pinus rigida were $230.0{\mu}S/cm$ and $82.0{\mu}S/cm$. 3. All pH values were decreased as the streamflow increased except long-term runoff in Daehan-Ri. The EC values also were increased as the streamflow increased, but EC of short-term runoff in Daehan-Ri was gradually decreased as the streamflow increased due to entrance of throughfall which has high EC values at the beginning of rainfall events. The DO concentrations of all experimental plots were elevated as the streamflow increased, because reaeration occurs at the surface of the stream as the increased discharge make turbulence. 4. pH of Stemflow and throughfall in Pinus densiflora were lower than in Quercus acutissima, but EC values were higher in Pinus densiflora. 5. Water purification was mostly influenced by forest soil in forest hydrological processes. 6. Stemflow and throughfall were more influenced by dry deposition and organic acid in crown and bark than those of wet deposition. During the stemflow and throughfall passed forest soil, these acidic stemflow and throughfall were neutralized, and stream water quality was neutral or slightly alkaline.

• Journal of the Korean Geotechnical Society
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• v.15 no.2
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• pp.153-164
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• 1999

The solubilization of BTEX was evaluated in aqueous surfactant solutions with and without several additives. Anionic surfactant(Sodium Dodecyl Sulfate, SDS) and nonionic surfactants (NEODOL(equation omitted)25-3 and $SOFTANOL\circledR-90$ were used as test surfactants. The effects of surfactant HLB(Hydrophile-Lipophile Balance) Number and hydrocarbon molar volume and polarity of BTEX on the MSR(Molar Solubilization Ratio), micelle-water partition coefficient of BTEX, and CMC(C,itical Micelle Concentration) were investigated. Optimizing treatment conditions applicable to enhanced solubilization was also studied by manupulating salinity or electrolyte control with additives of ethyl alcohol, hydrotrope, and electrolyte solution. The most effective surfactant for solubilization was found $SOFTANOL\circledR-90$, since HLB number of 13.6 is similar to those values of BTEX ranging between 11.4 and 12.2, which was also proved experimentally. Ethyl alchohol of 3% was the most effective additives in reducing CMC and improving solubilization among the conditions using SDS, NEODOL(equation omitted)25-3, and $SOFTANOL\circledR-90$ with three additives. The partitioning of BTEX between surfactant micelles and aqueous solutions was characterized by a mole fraction micelle-phase/aqueous phase partion coefficient, $K_m$. Values of log $K_m$. for BTEX compounds in surfactant solutions of this study range from 2.95 to 3.76(100mM SDS) and 2.95 to 3.49(117mM $SOFTANOL\circledR-90$. Log $K_m$ appears to be a linear function of log $K_{ow}$ for SDS and $SOFTANOL\circledR-90$. A knowledge of partitioning of BTEX in aqueous surfactant system can be a prerequisite for the understanding of the behavior of hydrophobic organic compounds in soil-water systems in which surfactants play a role in remediation of contaminated soil and facilitated transport.

• Korean Journal of Plant Resources
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• v.15 no.2
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• pp.164-171
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• 2002

Morphological characteristics and growth pattern of 10 Polygonatum collections indigenous to Korea were examined to select the promising medicinal, edible resources and horticultural crops. Plant heights of I0 collections ranged from 15 to 102cm. Stem type was ascending or erect, and node numbers per a stem was 6.2 to 23.2. Phyllotaxis type was alternate or verticillate, and leaf shape was elliptical or linear. Leave numbers per a stem was 5.2 to 63.4, and bract types were classified into bracteate and nonbracteate. Flowers bloomed from May 7 to May 30, and flowering period was 5 to 13 days. Inflorescence types were classified into racemose, corymbose, and umbellate. Flower numbers per a stem was 1.5 to 125.2, and flower length was 13.1 to 30.2㎜. Perianth shapes were classified into tubular, constrict and urceolate. Surface colors of rhizome were pale yellow, pale brown, brown, and dark brown. As a result of this experiment, P. sibiricum, P. odoratum var. pluriflorum and P. odoratum var. thunbergii were thought to be useful as the medicinal and edible resources plants. On the other hand, P. odoratum var. pluriflorum 'Variegata', and P. odoratum var. maximowiczii, P. lasianthum. P. involucratum, P. desoulavyi, P. humile, and P. inflatum were thought to be useful as horticultural plants.

• Journal of Korea Water Resources Association
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• v.35 no.1
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• pp.97-108
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• 2002

The use of land at the time of investigation of groundwater quality in the rapidly urbanized Bu-chon city is classified into 5 categories based on the change process of land use. The difference in groundwater quality according to the land use and its usage period is tested by non-parametric statistical procedures. The seven constituents of water quality with the highly frequent detection in the area for this study are used for the statistical test. The shallow groundwater quality within the areas of the same land use at the time of investigation varies significantly according to the period of land usage. The concentration of KMnO$_4$consumed and hardness is significantly higher in the old residential area (of more than 20 years old) than in the younger one (of less than 10 years old). The quality of the shallow groundwater is also significantly different among the three categories with the similar period of land usage (of more than 15 years old). The concentration of No$_3$-N, hardness and total solid is significantly higher in the residential area than in the agricultural one (namely, the area used as paddy fields 2 to 5 years ago). The median concentration of these constituents is 2.2 to 3.8 times higher in the residential area than in the agricultural one. The concentration of NO$_3$-N, KMnO$_4$, consumed and Cl is significantly higher in the industrial area than in the agricultural one. The median concentration of these constituents is 5.5 to 18 times higher in the industrial area than in the agricultural one. The concentration of KMnO$_4$consumed is significantly higher in the industrial area than in the residential area. The median concentration of these constituents is 12 times higher in the industrial area than in the residential one. The spatial distribution of shallow groundwater quality in the rapidly urbanized area is closely related to the period of land usage as well as the land use, which is presumed to be attributed to the difference in the concentration and leakage rate of the contaminants leaking from damaged sewer into shallow groundwater.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.660-670
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• 2005

Standard procedure for development of food list was established based on food intake data of 2001 National Health and Nutrition Survey and 2002 Seasonal Nutrition Survey for Total Diet Study. Foods were sorted in descending order of mean intake, and 54 items within cumulative percentage of 80 were selected, followed by selection of 16 additional items with consumption frequency of 10% or higher. Based on higher consumption in certain seasons, regions, sexes, and age classes, 14 additional items were added. Additional 17 items with probable high contents of heavy metals or 23 items with probable high pesticide residues were added. Altogether, 101 and 107 individual food items were included for heavy metal and pesticide residue lists, accounting for 84.9 and 83.3% mean energy intakes of Korean population, respectively.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.413-426
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• 2009

The study was conducted to investigate the effects of indigenous bacteria on geochemical behavior of toxic heavy metals in contaminated paddy soil near an abandoned mine. The effects of sulfate amendment to stimulate microbial sulfate reduction on heavy metal behaviors were also investigated. Batch-type experiments were performed with lactate or glucose as a carbon source to activate indigenous bacteria in the soil under anaerobic condition for 100 days. Sulfate (250 mg/L) was artificially injected at 60 days after the onset of the experiments. In the case of glucose supply, solution pH increased from 4.8 to 7.6 while pH was maintained at 7~8 in the lactate solution. The initial low pH in the case of glucose supply likely resulted in the enhanced extraction of Fe and most heavy metals at the initial experimental period. Lactate supply exerted no significant difference on the amounts of dissolved Zn, Pb, Ni and Cu between microbial and abiotic control slurries; however, lower Zn, Pb and Ni and higher Cu concentrations were observed in the microbial slurries than in the controls when glucose supplied. Sulfate amendment led to dramatic decrease in dissolved Cr and maintenance of dissolved As, both of which had gradually increased over time till the sulfate injection. Black precipitates formed in solution after sulfate amendment, and violarite($Fe^{+2}{Ni^{+3}}_2S_4$) was found with XRD analysis in the microbial precipitates. Conceivably the mineral might be formed after Fe(III) reduction and microbial sulfate reduction with coprecipitation of heavy metal. The results suggested that heavy metals which can be readily extracted from contaminated paddy soils may be stabilized in soil formation by microbial sulfate reduction.

• Journal of Dairy Science and Biotechnology
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• v.32 no.2
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• pp.93-100
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• 2014

In general, whey obtained from various cheese batches is being reused, so as to improve the texture and to increase the yield and the nutrient value of the various final milk-based products. In fact, re-usage of whey proteins, including whey cream, is a common and routine procedure. Unfortunately, most bacteriophages can survive heat treatments such as pasteurization. Hence, there is a high risk of an increase in the bacteriophage population during the cheese-making process. Whey samples contaminated with bacteriophages can cause serious problems in the cheese industry. In particular, the process of whey separation frequently leads to aerosol-borne bacteriophages and thus to a contaminated environment in the dairy production plant. In addition, whey proteins and whey cream reused in a cheese matrix can be infected by bacteriophages with thermal resistance. Therefore, to completely abolish the various risks of fermentation failure during re-usage of whey, a whey treatment that effectively decreases the bacteriophage population is urgently needed and indispensable. Hence, the purpose of this review is to introduce various newly developed methods and state-of-the-art technologies for removing bacteriophages from contaminated whey and whey products.