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1

Influence of weir construction on chemical water quality, physical habitat, and biological integrity of fish in the Geum River, South Korea

100%
Lee S.-J., An K.-G.
Polish Journal of Environmental Studies
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2019
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tom 28
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nr 4
The objectives of this study were to determine the long-term changes in water chemistry, physical habitat, and fish fauna/composition before and after construction of the Sejong Weir in Geum River, South Korea, during 2007–2014, and to evaluate the integrated ecological health based on chemical water quality, physical habitat, and biotic integrity using a star plot integration approach. As an indicator of water quality, the mean total phosphorus (TP) in the surface water decreased 2.6-fold after weir construction, indicative of P sedimentation from the water column due to structural changes from a lotic to a lentic system. The chlorophyll-a concentration decreased in response to P levels. Considering total nitrogen (TN), more than 91.7% of the total observations after weir construction (n = 96) had a TN:TP ratio >17, indicating potential P limitations on algal growth. The log-transformed TN:TP ratio had a weak positive correlation (p<0.005, R2 = 0.085, n = 96) with TN and a strong negative correlation (p<0.001, R2 = 0.575, n = 96) with TP. This indicated that the N:P ratio was regulated mainly by variations in P rather than N. After weir construction, the population of the lotic-type fish Zacco platypus decreased 13-fold, and the population of the lentic-type fish Pseudorasbora parva increased 3-fold. Overall, the integrated ecological health assessments revealed large degradations of >3-fold in biotic health, 2-fold in physical habitat health, and >5-fold in chemical health after weir construction.
2

Alpha-Synuclein is localized in a subpopulation of rat brain synaptic vesicles

81%
Lee S.-J., Jeon H., Kandror K. V.
Acta Neurobiologiae Experimentalis
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2008
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tom 68
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nr 4
Alpha-Synuclein is a neuronal protein implicated both in synaptic transmission and in neurodegenerative diseases. Although it is evident that this protein is enriched in the presynaptic terminals of neurons, localization in synaptic vesicles has not been conclusively determined. Here, we show that alpha-synuclein is present, but not enriched, in synaptic vesicles using highly purified synaptic vesicle preparations from rat brain homogenate. Immunoisolation of vesicles using antibodies against synaptophysin or synaptobrevin confirmed the presence of alpha-synuclein in synaptic vesicles. Additional separation of synaptic vesicles by sucrose velocity centrifugation showed that there are different subpopulations of synaptic vesicles and that alpha-synuclein is present only in a specific subpopulation, whereas synaptophysin and synaptobrevin were found in all the synaptic vesicles. Presence of alpha-synuclein only in a subset of synaptic vesicles suggests that this protein may have a specific function in synaptic vesicle cycling, hence in synaptic transmission.
3

Roles of nutrient regime and N:P ratios on algal growth in 182 Korean agricultural reservoirs

81%
Mamun M., Lee S.-J., An K.-G.
Polish Journal of Environmental Studies
|
2018
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tom 27
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nr 3
The principal aim of this study was to evaluate how nutrient regime and TN:TP ratios regulate algal chlorophyll in Korean agricultural reservoirs. We developed empirical models of log-transformed CHL-TN:TP ratio based on seasonality. Winter algal chlorophyll was highly influenced by the ratio of TN:TP (R² = 0.78, p<0.01) compared to chlorophyll-a in the spring (R² = 0.38, p<0.01), summer (R² = 0.50, p<0.01), and autumn (R² = 0.44, p<0.01), respectively. Regression analysis of log-transformed TN:TP ratios-TP and TN:TP ratios-TN on CHL-a showed that the ratio of TN:TP are highly influenced by the concentration of TP rather than TN. The ambient nutrient concentrations of the agricultural reservoirs showed positive linear relationships with water quality parameters of water temperature, pH, BOD, COD, DO, and TSS. Summer monsoon is an important factor that determines the nutrient regime, algal chlorophyll, and suspended solids in the reservoirs. Nutrient enrichment bioassays (NEBs) suggest that phosphorus was the primary limiting nutrient for algae production in the agricultural reservoirs. Analysis of trophic state index deviation (TSID) showed that P-limitation and biogenic turbidity (non-algal light limitation) were key regulating factors for algal growth in the reservoirs. Overall, our study suggested that the TN:TP ratio was the key regulating factor for algal biomass in the reservoirs.
4

Fish community dynamics in the artificial fishways of three different watersheds, and fish passage evaluations using a multi-metric fishway model

81%
Lee Y.-J., Lee S.-J., Bae D.-Y., An K.-G.
Polish Journal of Environmental Studies
|
2019
|
tom 28
|
nr 5
We analyzed fish community dynamics in fishways in the Yeongsan, Nakdong, and Geum river watersheds in South Korea and evaluated fish passage efficiency using a multimetric fishway assessment model, along with analyses of water chemistry and flow regime, from April to October 2016. The dominant fish in the fishways was Erythroculter erythropterus, with a mean relative abundance of 28.5% in all three watersheds. Omnivorous species and tolerant species were the dominant fish guilds in the fishway communities. The highest frequency of fish passage through the fishways occurred during the spawning season from April to June. During the summer monsoon, flow velocity increased rapidly and juvenile and young fish rarely passed through the fishways, which demonstrates that fish passage decreased significantly with increased current velocity (R²= 0.463, P<0.05). The ecological health, based on the fish health model, and the trophic state, based on the nutrient regime, were evaluated in the three watersheds. Overall, the multimetric model of fish passage efficiency, based on structural, hydrological, and biological metrics, showed that the Yeongsan fishway was the most suitable while the other two fishways were unsuitable.
5

Lotic ecosystem health assessments using an integrated analytical approach of physical habitat, chemical water quality, and fish multi-metric health metrics

81%
Lee S.-J., Lee E.-H., An K.-G.
Polish Journal of Environmental Studies
|
2018
|
tom 27
|
nr 5
This study evaluates integrative lotic ecosystem health using neural network modeling and principal component analysis of physical, chemical, and biological parameters in 33 streams and rivers of a large watershed. Water chemistry parameters were measured to detect chemical health, and physical habitat health was determined by a model of qualitative habitat evaluation index (QHEI). Also, biological health was determined by the multi-metric community fish model of index of biological integrity (IBI) and then analyzed trophic compositions and tolerance guilds. In addition, we analyzed fish tissues of liver, kidney, gill, vertebra, and muscle using a sentinel species of Zacco platypus. Chemical pollutions were closely associated with land-use patterns within the watershed and the locations of major point-sources. Model value of QHEI as a measure of physical habitat health averaged 144, indicating good health, and varied from 96 to 190 depending on the sampling sites. The proportion of sensitive fish species in the tolerance guilds had negative correlation with organic matter pollution (r = -0.716, p<0.001) and had positive a relationship with IBI (r = 0.683, p<0.001) and QHEI (r = 0.573, p = 0.001). The proportion of insectivore species, as a trophic composition indicator, was inversely correlated with BOD (r = -0.463, p = 0.007) and positive with IBI (r = 0.679, p<0.001). The analysis of the multi-layer perceptron (MLP) 14-5-1 model, based on the predicted IBI values in the training sites (R² = 0.999, MSE = 0.015) and testing sites (R² = 0.894, MSE = 27.4) showed high efficiency in the MLP model.
6
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Hearing impairment among Korean farmers, based on a 3-year audiometry examination

81%
Lee S., Lee K., Lee S.-J.
Annals of Agricultural and Environmental Medicine
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2019
|
tom 26
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nr 1
7
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Content available

Bioaerosol exposure by farm type in Korea

71%
Kim E. Y., Han J., Lee Y.-K., Kim W., Lee S.-J.
Annals of Agricultural and Environmental Medicine
|
2022
|
tom 29
|
nr 1
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