• Journal of Korean Society of Environmental Engineers
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• v.36 no.3
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• pp.221-230
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• 2014

In order to restore an ecologically damaged river, freshwater fish which inhabit at the target aquatic ecosystem have a great applicability as one of the essential indicators. Although the informations about the habitat conditions of freshwater fish are key elements reflecting biological, physical, and chemical properties of the aquatic environment, because of the lack of preceding related research and insufficient database with scattered data, they have not been applied effectively for the ecological river restoration projects in Korea. To cope with these problems, based on the nation-wide detailed investigation for domestic freshwater fish habitat conditions, we have selected 70 species considering the possibility for the candidates of flagship species, constructed a database for their population, physical, and chemical habitat properties, and suggested its application methodology for the river restoration projects. In particular, the utilization of the database has been enhanced by the additional statistical analysis to present their resistance and optimum ranges for physical, and chemical habitat properties respectively. It is expected that the database constructed in this study can be utilized for the calculation and evaluation of the appropriate ecological flow rate and target water quality for the selected flagship species (fish), and the basic data for the restoration of river environment.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1216-1221
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• 2012

This study is aimed to investigate microbiological contamination of Angelica gigas Nakai. A total of 111 samples including root, soil, and irrigation water were collected from farms and market to detect aerobic bacteria, Bacillus cereus, coliform, Escherichia coli, Listeria monocytogenes,. Salmonella spp., and Staphylococcus aureus. The contaminations of aerobic bacteria, coliform, and Bacillus cereus in the root during cultivation were found 6.71 log CFU $g^{-1}$, 4.13 log CFU $g^{-1}$, and 3.54 log CFU $g^{-1}$, respectively. The contamination of coliform and B. cereus were detected in all steps from harvesting to processing, with the highest count recorded from the cutting step. In marketing, the contaminations of aerobic bacterial, coliform, and B. cereus were 5.5~6.0 log CFU $g^{-1}$, 2.4~2.6 log CFU $g^{-1}$, and 3.5~4.0 log CFU $g^{-1}$, respectively. Listeria monocytogenes, Salmonella spp, and Staphylococcus aureus were not detected in any of samples. This result indicated that hygienic soil management and post harvest management should be performed to reduce the contamination of hazard microorganisms and to produce safe agro-products.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.1
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• pp.39-48
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• 2022

Using environmental DNA (eDNA) in the fisheries and oceanography fields, research on the diversity of biological species, the presence or absence of specific species and quantitative evaluation of species has considerably been performed. Up to date, no study on eDNA has been tried in the area of fisheries acoustics in Korea. In this study, the biomass of a dominant species in the northwestern waters of Jeju Island was examined using 1) the catch ratio of the species from trawl survey results and 2) the ranking ratio of the species from the eDNA results. The dominant species was Zoarces gillii, and its trawl catch ratio was 68.2% and its eDNA ratio was 81.3%. The Zoarces gillii biomass from the two methods was 7199.4 tons (trawl) and 8584.6 tons (eDNA), respectively. The mean and standard deviation of the acoustic backscattering strength values (120 kHz) from the entire survey area were 135.5 and 157.7 m²/nm², respectively. The strongest echo signal occurred at latitude 34° and longitude 126°15' (northwest of Jeju Island). High echo signals were observed in a specific oceanographic feature (salinity range of 32-33 psu and the water temperature range of 19-20℃). This study was a pilot study on evaluating quantitatively aquatic resources by applying the eDNA technique into acoustic-trawl survey method. Points to be considered for high-quality quantitative estimation using the eDNA to fisheries acosutics were discussed.

• Journal of Ecology and Environment
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• v.48 no.1
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• pp.24-31
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• 2024

Background: Honey from different geographical origins can have distinct characteristics due to variations in the floral sources available to stingless bees in different regions. The most abundant stingless bee for meliponiculture in Thailand is Tetragonula pagdeni. However, only a few studies about the properties of honey from a different origin were carried out. The objective of this study was focused on a comparative study to evaluate the melissopalynological, physicochemical, antioxidant activities, and total phenolic contents (TPCs) of stingless bee honey produced by T. pagdeni from different parts of Thailand. Results: Fifty honey samples were collected from five locations, and the physicochemical properties of T. pagdeni honey samples are acidic (pH 3.02-4.15) and have a high water content (18.42-25.06 %w/w), which is related to the regions of meliponary. Melisopalynological analysis reveals the predominant pollen from Melaleuca quinquenervia, Cocus nuciferca, Nephelium lappaceum, Salacca wallichiana, and multiflora honey. All honey samples were analyzed for their TPC and 2,2-diphenyl1-picrylhydrazyl radical scavenging activity. The results show that all samples had high TPC and antioxidant activities with a strong correlation (p < 0.05). Conclusions: The data from this study indicates the importance of geographical origin, which links physicochemical properties, phenolic compounds, and functional characteristics to their floral. Besides, the floral sources and harvesting location affected the properties of stingless bee honey. Our results identify Melaleuca honey as a promising source of phenolic content and antioxidant activity that can be used as a functional food, as well as multiflora and Cocus honey. However, further studies are required to characterize the phenolic compound and its biological potential, which could be a stingless bee honey biomarker and quality control, simultaneously with the physicochemical analysis.

• Food Science of Animal Resources
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• v.25 no.4
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• pp.430-435
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• 2005

Current study was conducted to investigate the effect of organic selenium supplementation originated from mushroom culture medium on meat quality of Hanwoo sleets. The result showed that organic selenium supplementation of 0.9 ppm (DM based ratio) for 2 (T1), 4 (T2) and 6 (T3) months had no effect on moisture content in longissimus muscle, with 63 to $66\%$ compared to non-supplemented control group Similarly, intramuscular fat content ranged from 11.7 to $16.4\%$ did not differ between the treatment groups (p>0.05). T3 group showed the highest protein content with $20.8\%$ while T2 group had the lowest content with $19.2\%$ The data indicated that organic selenium supplementation to the experimental concentration had indictable effect on proximate composition The treatments similarly had no influence on physical and biological characteristics of longissimus muscle, where cooking loss and shear force ranged from 20 to $21\%$ and from 3.6 to 4.4kg, respectively. On the other hand, muscle pH at 24 h postmortem showed 5.52, 5.57, 5.50, 5.50 for control, T1, T2 and T3, respectively, indicating that the longer feeding period resulted in the lower ultimate un A similar trend was observed from water-holding capacity (63.8, 64.4 and $64.2\%$ for T1, T2 and T3, respectively) which was significantly higher than con01 group of $59.5\%$ For sensory evaluation, juiciness did not differ between the treatment groups, but n and n (5.30 and 5.28, respectively) showed significantly tender mat Particularly, T2 group received significantly higher flavor score among the treatment groups including controls. The data indicated that organic selenium supplementation to the experimental concentration had no effect on beef quality, but the treatment effect on anti-oxidation function is remained for further studies.

• Korean Journal of Ecology and Environment
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• v.41 no.2
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• pp.188-197
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• 2008

This research was a preliminary case study to determine the levels of total mercury in the tissues of sentinel species (Zacco platypus) and ecological health in relation to habitat characteristics and chemical conditions. We collected fishes in Gap Stream during June$\sim$October 2007 and analyzed the total mercury from five types of tissues such as liver, kidney, gill, vertebrae and muscle of Zaceo platypus using Direct Mercury Analyzer (DMA-80, US EPA Method 7473). Mean concentrations of total [Hg], based on all tissues, was 67.2 and $20.7\;{\mu}g\;kg^{-1}$, in the upstream and downstream site, respectively, indicating 3 times greater level in the upstream. In other words, the levels were higher in the pristine upstream than the downstream influenced by the wastewater disposal plant. Chemical water quality, based on BOD, COD and nutrients (TN, TP) showed that severe degradation occurred in the downstreams than the upstreams. Index of Biological Integrity (IBI) using fish multi-metric model averaged 32, indicating a "good$\sim$fair" condition and varied from 42 (excellent$\sim$good) at S2 to 22 (fair$\sim$poor) at S5 depending on the sites sampled. Qualitative Habitat Evaluation Index (QHEI) in the all sites averaged 142, which was judged as "good" habitat health, but showed a high variation (181 in Site 2 vs. 67 in Site 5). Overall data suggest that health conditions, based on IBI and QHEI, was better in the upstream sites but the mercury bioaccumulation levels in the fish tissues were opposite. We believe that measurements of various parameters are required for a diagnosis of integrative ecosystem health.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.1
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• pp.41-51
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• 2012

We produced Hwanggiju (added 0.5~2.0% of ground Astragali Radix compared to starch contents) and investigated the physicochemical characteristics, DPPH free radical scavenging activities, polyphenol contents, and sensory evaluation. For all treatments, the initial pH was 3.9~4.1 and gradually decreased for 6 days from the 1st mashing day, and then rapidly increased to 4.67. As the fermentation proceeded, total acid contents increased in most of the treatments, reduced temporarily after the 2nd mashing time because of the addition of starch material and water, and then slightly rose again. There were little changes in pH and total acid contents followed by adding ground Astragali Radix (AR) to the fermentation periods. Amino acidities of all treatments showed patterns of which consistently rose as the fermentation proceeded and slightly reduced followed by increasing the addition rate of ground AR to the mashes. Soluble solid and alcohol contents also increased continuously and there were few differences among the treatments followed by adding to the ground AR rate. In color, there was no differences in L value, but a and b value showed significant differences by adding ground AR rate. In DPPH free radical scavenging activities, the control (no AR added) showed 53.6% and when grinded AR added, there were improving effects of the activities (0.52~6.9%). In polyphenol contents, the control was 1.05 mg/mL and the ground AR added treatments increased slightly. In the sensory evaluation, the control received a relatively high score ($5.0{\pm}1.0$), and the treatments which added 0.5% ground AR during the 2nd mashing time were also well received ($4.5{\pm}1.3$).

• Journal of Life Science
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• v.16 no.3 s.76
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• pp.534-539
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• 2006

In the ozone disinfection unit process of a piston type batch reactor with continuous ozone analysis using a flow injection analysis (FIA) system, the CT values for 1 log inactivation of Cryptosporidium parvum by viability assays of DAPI/PI and excystation were $1.8{\sim}2.2\;mg/L{\cdot}min$ at $25^{\circ}C$ and $9.1mg/L{\cdot}min$ at $5^{\circ}C$, respectively. At the low temperature, ozone requirement rises $4{\sim}5$ times higher in order to achieve the same level of disinfection at room temperature. In a 40 L scale pilot plant with continuous flow and constant 5 minutes retention time, disinfection effects were evaluated using excystation, DAPI/PI, and cell infection method at the same time. About 0.2 log inactivation of Cryptosporidium by DAPI/PI and excystation assay, and 1.2 log inactivation by cell infectivity assay were estimated, respectively, at the CT value of about $8mg/L{\cdot}min$. The difference between DAPI/PI and excystation assay was not significant in evaluating CT values of Cryptosporidium by ozone in both experiment of the piston and the pilot reactors. However, there was significant difference between viability assay based on the intact cell wall structure and function and infectivity assay based on the developing oocysts to sporozoites and merozoites in the pilot study. The stage of development should be more sensitive to ozone oxidation than cell wall intactness of oocysts. The difference of CT values estimated by viability assay between two studies may partly come from underestimation of the residual ozone concentration due to the manual monitoring in the pilot study, or the difference of the reactor scale (50 mL vs 40 L) and types (batch vs continuous). Adequate If value to disinfect 1 and 2 log scale of Cryptosporidium in UV irradiation process was 25 $mWs/cm^2$ and 50 $mWs/cm^2$, respectively, at $25^{\circ}C$ by DAPI/PI. At $5^{\circ}C$, 40 $mWs/cm^2$ was required for disinfecting 1 log Cryptosporidium, and 80 $mWs/cm^2$ for disinfecting 2 log Cryptosporidium. It was thought that about 60% increase of If value requirement to compensate for the $20^{\circ}C$ decrease in temperature was due to the low voltage low output lamp letting weaker UV rays occur at lower temperatures.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.94-131
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• 2007

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2004 and 2005 has been done. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation of facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat, humidity was also interesting for comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing topics. Well developed CFD and flow visualization(PIV, PTV and LDV methods) technologies were widely applied for developing facilities and their systems. (2) The research trends of the previous two yews are surveyed as groups of natural convection, forced convection, electronic cooling, heat transfer enhancement, frosting and defrosting, thermal properties, etc. New research topics introduced include natural convection heat transfer enhancement using nanofluid, supercritical cooling performance or oil miscibility of $CO_2$, enthalpy heat exchanger for heat recovery, heat transfer enhancement in a plate heat exchanger using fluid resonance. (3) The literature for the last two years($2004{\sim}2005$) is reviewed in the areas of heat pump, ice and water storage, cycle analysis and reused energy including geothermal, solar and unused energy). The research on cycle analysis and experiments for $CO_2$ was extensively carried out to replace the Ozone depleting and global warming refrigerants such as HFC and HCFC refrigerants. From the year of 2005, the Gas Engine Heat Pump(GHP) has been paid attention from the viewpoint of the gas cooling application. The heat pipe was focused on the performance improvement by the parametric analysis and the heat recovery applications. The storage systems were studied on the performance enhancement of the storage tank and cost analysis for heating and cooling applications. In the area of unused energy, the hybrid systems were extensively introduced and the life cycle cost analysis(LCCA) for the unused energy systems was also intensively carried out. (4) Recent studies of various refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and of alternative refrigerants including carbon dioxide. Efficiency of various compressors and expansion devices are also dealt with for better modeling and, in particular, performance improvement. Thermoelectric module and cooling systems are analyzed theoretically and experimentally. (5) According to the review of recent studies on ventilation systems, an appropriate ventilation systems including machenical and natural are required to satisfied the level of IAQ. Also, an recent studies on air-conditioning and absorption refrigeration systems, it has mainly focused on distribution and dehumidification of indoor air to improve the performance were carried out. (6) Based on a review of recent studies on indoor environment and building service systems, it is noticed that research issues have mainly focused on optimal thermal comfort, improvement of indoor air Quality and many innovative systems such as air-barrier type perimeter-less system with UFAC, radiant floor heating and cooling system and etc. New approaches are highlighted for improving indoor environmental condition as well as minimizing energy consumption, various activities of building control and operation strategy and energy performance analysis for economic evaluation.