• Journal of Life Science
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• v.22 no.3
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• pp.366-372
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• 2012

This study was conducted to estimate the extent of linkage disequilibrium (LD) and effective population size using whole genomic single nucleotide polymorphisms (SNP) genotyped by DNA chip in Hanwoo. Using the blood samples of 35 young bulls born from 2005 to 2008 and their progenies (N=253) in a Hanwoo nucleus population collected from Hanwoo Improvement Center, 51,582 SNPs were genotyped using Bovine SNP50 chips. A total of 40,851 SNPs were used in this study after elimination of SNPs with a missing genotyping rate of over 10 percent and monomorphic SNPs (10,730 SNPs). The total autosomal genome length, measured as the sum of the longest syntenic pairs of SNPs by chromosome, was 2,541.6 Mb (Mega base pairs). The average distances of all adjacent pairs by each BTA ranged from 0.55 to 0.74 cM. Decay of LD showed an exponential trend with physical distance. The means of LD ($r^2$) among syntenic SNP pairs were 0.136 at a range of 0-0.1 Mb in physical distance and 0.06 at a range of 0.1-0.2 Mb. When these results were used for Luo's formula, about 2,000 phenotypic records were found to be required to achieve power > 0.9 to detect 5% QTL in the population of Hanwoo. As a result of estimating effective population size by generation in Hanwoo, the estimated effective population size for the current status was 84 heads and the estimate of effective population size for 50 generations of ancestors was 1,150 heads. The average decreasing rates of effective population size by generation were 9.0% at about five generations and 17.3% at the current generation. The main cause of the rapid decrease in effective population size was considered to be the intensive use of a few prominent sires since the application of artificial insemination technology in Korea. To increase and/or sustain the effective population size, the selection of various proven bulls and mating systems that consider genetic diversity are needed.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.4
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• pp.214-226
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• 2013

To understand the changing patterns in phytoplankton communities, we conducted 12 surveys along the Nakdong River, its estuary, and adjacent coastal areas between January 2011 and October 2012 (during the period of barrage construction and sediment dredging). Monthly precipitation ranged from 0 to 502 mm during the survey period, and salinity ranged between 0.1 psu and 0.3 psu in the Nakdong River, regardless of the depth, indicating no seawater influence, while salinity showed large seasonal fluctuations in the estuarine and coastal station, ranging from 0.1 psu to 34.8 psu. A total of 402 phytoplankton species were identified, 178 species from the river and 331 species from the estuary and coastal areas. Phytoplankton standing crop increased in 2012 compared to that in 2011, and was found to be highest in the river, followed by the estuary and coastal areas. Among the top 20 species in frequency of occurrence and dominance, Stephanodiscus spp., Aulacoseira granulata, and Aulacoseira granulata var. angustissima and Pseudo-nitzschia spp. were important species along the river-estuary-coastal areas. Diatoms were the major taxonomic group inhabiting the Nakdong river-estuary-coastal areas. A comparison of seasonal dominant phytoplankton species revealed a slight decrease over the years, from 13 species in 2011 to 10 species in 2012. However, no significant difference was found in the diversity of phytoplankton species between the two survey years, although lightly greater diversity was observed in the coastal areas than in the river and estuary. Cluster analysis with community composition data revealed that the community structure varied significantly in 2011 depending on the time of survey, while in 2012, it hardly showed any variation and was simpler. An increase in the phytoplankton standing crop, fewer dominant species, and simpler community structure in 2012 compared to those in 2011 are probably due to the rapid environmental changes along the Nakdong River. To investigate these ecological relationships, it is necessary to conduct further studies focusing on integrated analyses of biocenosis, including phytoplankton with respect to the changes in nutrient distribution, variation of freshwater discharge, and effect area of freshwater in the Nakdong estuary and adjacent coastal areas.

• Korean Journal of Ecology and Environment
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• v.35 no.3 s.99
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• pp.198-212
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• 2002

A numerical variation and abnormalities were studied on egg bags and embryos of Korean salamander, Hynobius leechii from agricultural habitat. The teratogenic and toxic effects of fungicide benomyl were also investigated with early embryos from non-agricultural habitat. We collected 144 egg bags from agricultural region, and 3418 of early embryos were contained. The lengths of egg bags were varied from 10 to 23 cm and the most frequent length was 19 cm. The number of embryos was varied from 7 to 43, and the most frequent range was 22 to 26. Spontaneous abnormalities were occurred in 406 embryos among 116 egg bags, and 24 kinds of external abnormalities were found. Individuals showing severe external defect were histologically studied and they showed optic dyspalsia, thyroid carcinoma, somatic muscular dysplasia, partial biaxial structure, decrease of red blood cells in the heart, cephalic degeneration and intestinal dysplasia. 385 embryos from non-agricultural region were exposed to 200 nM${\sim}$ 1 ${\mu}$M of benomyl at blastula or gastrula for 12 days. All embryo were dead in the concentration of 1 ${\mu}$M (LD$_{100}$) and 75% of embryos were dead in 800nM of benomyl. Speciflc effect due to benomyl was acrania or cephalic dysplasia and this restult suggests that the benomyl inhibit stongly to the development of neural tissue. These abnormal developments may be caused by antimitotic action, inhibition of tubulin complex, destruction of microtubule, inhibitions of neurulation and closing of neural fold, and by the inhibition of the movement of neural crest cells.

• Korean Journal of Ecology and Environment
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• v.35 no.3 s.99
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• pp.152-159
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• 2002

The seasonal variations of nitrifying bacterial population sampled from 3 sites in Moon-Chon reservoir were analyzed by in situ hybridization with fluorescently labeled rRNA-targeted oligonucleotide probes from August 2000 until July 2001. In addition, physico-chemical parameters such as temperature, pH, chi-a and DOC were measured to determine correlations between those factors and the size of nitrifying bacterial populations. Total bacterial numbers varied in the range of $0.8{\sim}1.5{\times}10^6\;cells/ml$ independent of sites and had the maximal values in March at all 3 stations. The ratio of eubacteria to total bacteria ranged from 44.9% to 79.5%, and the ratio of each nitrifying bacteria to eubacterial numbers reached only $1.0{\sim}7.4%$. The variations of ammonia-oxidizing bacteria ranged from $1.1{\times}10^4$ to $3.0{\times}10^4\;cells/ml$ without noticeable peak values whereas those of nitrite-oxidizing bacteria varied in $1.3{\sim}5.7{\times}10^4\;cells/ml$ with the increasing tendency in winter regardless of the sites. Moreover it was observed that the numbers of nitrite-oxidizing bacteria were higher than those of ammonia-oxidizing bacteria. Total bacterial numbers correlated with water temperature (r = 0.355, p<0.05) and DOC (r = 0.58G, p<0.01) positively whereas nitrite-oxidizing bacteria correlated with temperature (r = -0.416, p<0.05) and pH (r = -0.568, p = 0.001) negatively. In addition, DOC represented good correlations with eubacterial numbers (r = 0.448, p<0.01). These results indicate that temperature, DOC and pH might be one of the main factors affecting variations of bacterial populations in the aquatic ecosystem. It was also suggested that FISH method is a useful tool for detection of slow growing nitrifying bacteria.

• Korean Journal of Ecology and Environment
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• v.48 no.3
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• pp.176-187
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• 2015

In this study, we hypothesized that the size of wintering crane population would change due to the climate factors. We assumed that wintering population size would differ by climate values in January, which is the coldest period in year. Especially, White-naped cranes were able to choose wintering site between Cheorwon and other alternative place where snow coverage had low influence, differing from Red crowned cranes. For this reason, we predicted the population size of White-naped cranes would fluctuate according to the extent of snow coverage in Cheorwon. Therefore we used snow coverage data based on MODIS and climate data from KMA (Korea Meteorological Administration) that are generally used. We analyzed the crane's population size in Cheorwon in January from 2002 to 2014. The temperature in the Cheorwon increased from 2002 to wintering period in 2007~ 2008 and went down, showing the lowest temperature in 2011~ 2012. With this phenomenon, warmth index showed the similar pattern with temperature. Amount of newly accumulated snow (the amount of snow that fallen from 0:01 am to 11:29 pm in a day) was low after 2002, but rapidly increased in 2010~ 2011 and 2011~ 2012. The area of snow coverage rapidly declined from 2002 to 2005~ 2006 but suddenly expanded in wintering period in 2009~ 2010 and 2010~ 2011. Wintering population size of the White-naped cranes decreased as snow coverage area increased in January and the highest correlation was found between them, compared to the other climatic factors. However, the number of individuals of Red crowned cranes had little relationship with general climate factors including snow cover range. Therefore it seems that population size of the Red crowned crane varied by factors related with habitat selection such as secure roosting site and area of foraging place, not by climatic factors. In multiple regression analysis, wintering population of White-naped cranes showed significant relationship with logarithmic value of snow cover range and its period. Therefore, it suggests that the population size of the White-naped crane was affected by snow cover range n wintering period and this was because it was hard for them to find out rice grains which are their main food items, buried in snow cover. The population size variation in White-naped cranes was caused by some individuals which left Cheorwon for Izumi where snow cover had little influence on them. The wintering population in Izumi and Cheorwon had negative correlation, implying they were mutually related.

• Korean Journal of Ecology and Environment
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• v.42 no.1
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• pp.85-94
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• 2009

This study examines the operational effectiveness of a Convection Current Aeration System (CCAS) in reservoir. CCAS was run from June, 2008 when the thermocline begun forming in the reservoir. This paper reviews the influence of stratification, dissolved oxygen dynamics and temperature in the lake's natural state from June to October 2008. The survey was done on a week basis. Upwelling flow effects a radius of $7{\sim}10m$ at a surface directly and was irrelevant to the strength of thermocline. On the other hand, it was affected the number of working days, and strength of thermocline at vertical profiles of the reservoir. Longer CCAS run, the deeper was the vertical direct flow area. However it didn't break the thermocline during summer season of 2008. The operating efficiency of the CCAS in the reservoir depends on hydraulics and meteological conditions. Computational Fluid Dynamics (CFD) is a very useful tool for evaluating the operating efficiency of fluid dynamics. The geometry for CFD simulation consists of a cylindrical vessel 25 m radius and 40 m height. The CCAS is located in center of domain. The non-uniform tetrahedral meshes had a bulk of the geometry. The meshes ranged from the coarse to the very fine. This is attributed to the cold water flowing into the downcomer and rising, creating a horizontal flow to the top of the CCAS. The result of CFD demonstrate a closer agreement with surveyed data for temperature and flow velocity. Theoretical dispersion volume were calculated at 8m depth, 120 m diameter working for 30 days and 10 m depth, 130 m diameter working for 50 days.

• Korean Journal of Ecology and Environment
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• v.47 no.spc
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• pp.48-56
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• 2014

Weekly changes of water environments and phytoplankton community with the salinity gradients were investigated at Gyoungpo Lake from April to November in 1998 and 2012. Underwater crossam in Gyoungpo Lake was removed in 2004. Thereafter, average salinity of Gyoungpo lake increased from 7.5 ppt in 1998 to 20 ppt in 2012. A total of 99 and 80 species of phytoplankton was observed from the sampled in 1998 and 2012, respectively. The number of common species during the 2 separate years was 40. Transparency, SS, $NO_3-N$ concentration and N/P ratio in 2012 were lower than those in 1998. During the period of water shortage (April, May) of 2012 transparency decreased due to decreased salinity and increased SS and Chl. a. Correlation coefficients between species and community scores of DCA ordination based on data matrix of the phytoplankton revealed larger variation among sampling seasons in 1998 than in 2012. The increase of seawater influx and conversion rates following the removal of the underwater crossbeam might explain such a differential variation. Gymnodium sp., Peridinium sp., Prorocentrum sp., Nitzschia longissima, Schroederia setigera, Lyngbya sp., Asterococcus limneticus, Asterococcus superbus and Cyclotella meneghiniana were found to well adapt at the high salinities in 2012. Comparatively, Asterrionella formosa, Nitzschia frustulum, Chlorella ellipsoidea, Scenedesmus bijuga and Scenedesmus ellipsoideus were observed at lower salinities in 1998. Two quite contrasting phytoplankton communities were found in the two seasons of a year, spring with limited precipitation and summer, the flood season.

• Journal of Nutrition and Health
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• v.52 no.6
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• pp.529-539
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• 2019

Purpose: Sprouts of evening primrose (Oenothera laciniata, OL) were reported to have high contents of flavonoids and potent antioxidant activity. This study examined the antioxidant and antiobesity activities of OL sprouts to determine if they could be a natural health-beneficial resource preventing obesity and oxidative stress. Methods: OL sprouts were extracted with 50% ethanol, evaporated, and lyophilized (OLE). The in vitro antioxidant activity of OLE was examined using four different tests. The antiobesity activity and in vivo antioxidant activity from OLE consumption were examined using high fat diet-induced obese (DIO) C57BL/6 mice. Results: The IC₅₀ for the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging and superoxide dismutase (SOD)-like activities of OLE were 26.2 ㎍/mL and 327.6 ㎍/mL, respectively. OLE exhibited the ferric reducing antioxidant power (FRAP) activity of 56.7 ㎍ ascorbic acid eq./mL at 100 ㎍/mL, and an increased glutathione level by 65.1% at 200 ㎍/mL compared to the control in the hUC-MSC stem cells. In an animal study, oral treatment with 50 mg or 100 mg of OLE/kg body weight for 14 weeks reduced the body weight gain, visceral fat content, fat cell size, blood leptin, and triglyceride levels, as well as the atherogenic index compared to the high fat diet control group (HFC) (p < 0.05). The blood malondialdehyde (MDA) level and the catalase and SOD-1 activities in adipose tissue were reduced significantly by the OLE treatment compared to HFC as well (p < 0.05). In epididymal adipose tissue, the OLE treatment reduced the mRNA expression of leptin, PPAR-γ and FAS significantly (p < 0.05) compared to HFC while it increased adiponectin expression (p < 0.05). Conclusion: OLE consumption has potent antioxidant and antiobesity activities via the suppression of oxidative stress and lipogenesis in DIO mice. Therefore, OLE could be a good candidate as a natural resource to develop functional food products that prevent obesity and oxidative stress.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.874-882
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• 2017

As the interest on the air-pollution is gradually rising up at home and abroad, automotiv e and fuel researchers have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research has brought forward three main issues : evaporative, performance, air pollution. In addition, researcher studied the environment problems of the bio-ethanol, bio-butanol, bio-ETBE (Ethyl Tertiary Butyl Ether), MTBE (Methyl Tert iary Butyl Ether) fuel contained in the fuel as octane number improver. The researchers have many dat a about the health effects of ingestion of octane number improver. However, the data support the con clusion that octane number improver is a potential human carcinogen at high doses. Based on the bio-fuel and octane number improver types (bio-ethanol, bio-butanol, bio-ETBE, MTBE), this paper dis cussed the influence of gasoline fuel properties on the evaporative emission characteristics. Also, this p aper assessed the acceleration and power performance of gasoline vehicle for the bio-fuel property. As a result of the experiment, it was found that all the test fuels meet the domestic exhaust gas standards, and as a result of measurement of the vapor pressure of the test fuels, the bio - ethanol : 15 kPa and the biobutanol : 1.6 kPa. thus when manufacturing E3 fuel, Increasing the biobutanol content reduces evaporation gas and vapor pressure. In addition, Similar accelerating and powering performance was shown for the type of biofuel and when bio-butanol and bio-ethanol were compared accelerated perf ormance was improved by about 3.9% and vehicle power by 0.8%.

• Korean Journal of Remote Sensing
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• v.14 no.4
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• pp.353-365
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• 1998

Light absorption coefficient per unit mass of particles, i.e., specific absorption coefficient, is important as one of the main parameters in developing algorithms for ocean color remote sensing. Specific absorption coefficient of chlorophyll ($a^*_{ph}$) and suspended sediment ($a^*_{ss}$) were analyzed with a spectrophotometer using the "wet filter technique" and "Kishino method" for the seawater collected in the Yellow and Mediterranean Sea. An improved data-recovery method for the filter technique was also developed using spectrum slopes. This method recovered the baselines of spectrum that were often altered in the original methods. High $a^*_{ph}({lambda})$ values in the oligotrophic Mediterranean Sea and low values in the Yellow Sea were observed, ranging 0.01 to 0.12 $m^2$/mg at the chlorophyll maximum absorption wavelength of 440 nm. The empirical relationship between $a^*_{ph}$(440nm) and chlorophyll concentrations () was found to fit a power function ($a^*_{ph}$=0.039 $^{-0.369}$), which was similar to Bricaud et al. (1995). Absorption specific coefficients for suspended sediment ($a^*_{ss}$) did not show any relationship with concentrations of suspended sediment. However, an average value of $a^*_{ss}$ ranging 0.005 - 0.08 $m^2$/g at 440nm, was comparable to the specific absorption coefficient of soil (loess) measured by Ahn (1990). The morepronounced variability of $a^*_{ss}$ than $a^*_{ph}$ was determined from the variable mixing ratio values between particulate organic matter and mineral. It can also be explained by a wide size-distribution range for SS which were determined by their specific gravity, bottom state, depth and agitation of water mass by wind in the sea surface.