• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.925-936
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• 2005

The present study evaluated whether pentoxifylline added to the freezing extender could improve the sperm characteristics and function in canine frozen semen. Also the conception rate following AI with frozen-thawed semen was investigated. The beneficial effects of pentoxifylline supplementation were visible in motility, viability, acrosome reaction, and tail swelling patterns. Especially, highest sperm viability and function were obtained in the forzen semen supplemented with 1mM pentoxifylline. The follicle size measured by ultrasonography was 6.48 mm, 11.52 mm and 8.9 mm on 11, 13 and 15 days after the onset of natural estrus, respectively and ovulation occurred on 13 and 15 days. The pregnancy rates in bitches inseminated with frozen semen on natural and induced estrus were 71.4% and 75.0%, respectively. There was no significant difference between the pregnancy rates in bitches inseminated with frozen semen following natural and induced estrus, but the litter size was slightly increased in natural cycle.

• Journal of Animal Science and Technology
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• v.55 no.5
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• pp.483-488
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• 2013

To develop a sustainable composting method for livestock mortality, a natural aeration-composting process was designed and the influences of bulking materials on the mortality composting process were studied. Bulking materials (e.g., compost, swine manure, sawdust, and rice husks), easily supplied at the scene of an animal mortality outbreak, were tested in this research. A lab-scale composting system (W34 ${\times}$ L60 ${\times}$ H26 cm) was made using 100 mm styrofoam, and natural aeration was achieved through pipes installed on the bottom of the system. Four treatments were designed (compost, compost + swine feces, sawdust, and rice husks treatment groups) and all experiments were done in triplicates. During composting for 40 days, no leachate was observed in compost and sawdust treatment groups, whereas 18 and 8.2 ml leachate/kg-mortality was emitted from the compost + feces and rice husks treatment groups, respectively. Dimethyl disulfide (DMDS) emission during the composting was very low in all treatment groups, possibly due to the bio-filtering function of the compost cover layer on the pile. The mortality degradability in compost, compost + feces, sawdust, and rice husks groups was 25.3, 25.8, 13.5, and 14.5%, respectively, showing significantly higher levels in compost and compost + feces groups (p<0.05). Also, only the compost + feces group produced enough heat (over $55^{\circ}C$) and lasted for 7 days, indicating that bio-security cannot be guaranteed without feces supplementation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.3
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• pp.299-306
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• 2014

Fresh edible sweet corns demand relatively short period to harvest fresh ears, which can allow farmers to make a choice sweet corns for various cropping systems. For this reason, we were to find the optimum planting date of late-planted sweet corns to sell fresh ears in the autumn linked to cropping system with winter crops, investigating yield and properties of marketable fresh ears and growth traits of sweet corns (cv. 'Godangok' and cv. 'Guseulok') depending on planting dates such as 10 July, 20 July, and 30 July in Suwon 2012 and 2013, respectively. The 20 July-planted sweet corns showed the most fresh ear yield. However, the 10 July-planted and the 30 July-planted had 32% less yield caused by consecutive rainfall from 10 July through 20 July, and 15% less yield due to low air temperature during ripening than the 20 July-planted, respectively. The 10 and 20 July-planted sweet corns had average 140g of a fresh ear weight and 15% heavier ear than the 30 July-planted. For the July-planted sweet corns, silking days after planting ($r=-0.80^{**}$), and harvesting days after silking ($r=-0.97^{**}$) and planting ($r=-0.91^{**}$) were highly negatively correlated with daily mean air temperature during the period, resulting in it takes 1,100 growing degree days (GDD) to harvest fresh ears from the July-planted sweet corns. The fresh ears of the 20 July-planted sweet corns are able to be harvested by early October. Therefore it will be a good choice for the cropping system based on winter vegetable cash crops such as temperate garlic and onion with medium or late maturity. Among three planting dates 20 July-planted sweet corns had the best field performance in every year considering fresh ear yield, ear size, and stability to grow.

• Korean Journal of Poultry Science
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• v.32 no.3
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• pp.187-193
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• 2005

This study was carried out to investigate the effect of the bleeding times(30sec., 90sec., 150sec.) at slaughtering process on meat quality and storage properties of broiler. The redness$(a^{\ast}\;value)$ of skin, wing, leg muscle decreased at high bleeding time(150sec.). However, there was no significant difference in breast muscle. WHC(water holding capacity) of breast muscle decreased from $63.64\%$ at low bleeding time(30sec.) to $61.06\%$ at high bleeding time. TBARS(thiobarbituric acid-reactive substance) values were 0.18 mgMA/kg at the low bleeding time, 0.16 mgMA/kg at the middle bleeding time(90sec.) and 0.21mgMA/kg high bleeding time on 3 days of storage. Total aerobic plate counts(TPC) were $6.25logCFU/cm^2$ at the low bleeding time, $6.25logCFU/cm^2$ at the middle bleeding time and $6.53logCFU/cm^2$ at the high bleeding time. The TPC was increased as the bleeding time increased. In conclusion, meat color of chicken were acceptable when the carcasses were slaughtered at the high bleeding time.

• Journal of Korea Water Resources Association
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• v.47 no.2
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• pp.145-159
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• 2014

This study is to evaluate the future climate change impact on turbidity water and eutrophication for Chungju Lake by using CE-QUAL-W2 reservoir water quality model coupled with SWAT watershed model. The SWAT was calibrated and validated using 11 years (2000~2010) daily streamflow data at three locations and monthly stream water quality data at two locations. The CE-QUAL-W2 was calibrated and validated for 2 years (2008 and 2010) water temperature, suspended solid, total nitrogen, total phosphorus, and Chl-a. For the future assessment, the SWAT results were used as boundary conditions for CE-QUAL-W2 model run. To evaluate the future water quality variation in reservoir, the climate data predicted by MM5 RCM(Regional Climate Model) of Special Report on Emissions Scenarios (SRES) A1B for three periods (2013~2040, 2041~2070 and 2071~2100) were downscaled by Artificial Neural Networks method to consider Typhoon effect. The RCM temperature and precipitation outputs and historical records were used to generate pollutants loading from the watershed. By the future temperature increase, the lake water temperature showed $0.5^{\circ}C$ increase in shallow depth while $-0.9^{\circ}C$ in deep depth. The future annual maximum sediment concentration into the lake from the watershed showed 17% increase in wet years. The future lake residence time above 10 mg/L suspended solids (SS) showed increases of 6 and 17 days in wet and dry years respectively comparing with normal year. The SS occupying rate of the lake also showed increases of 24% and 26% in both wet and dry year respectively. In summary, the future lake turbidity showed longer lasting with high concentration comparing with present behavior. Under the future lake environment by the watershed and within lake, the future maximum Chl-a concentration showed increases of 19 % in wet year and 3% in dry year respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.253-258
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• 2006

An empirical model of nitrous oxide emission from agricultural soil has been applied. It is based on the relationship between $N_2O$ and three soil parameters, soil mineral N(ammonium plus nitrate) content in the topsoil(0-15cm), soil water-field pore space, and soil temperature, determined in a study on clay loam and sandy loam at the pepper field in 2004. For comparisons between estimated and observed values of $N_2O$ emissions in the pepper field, it was investigated that $N_2O$ amount in the clay loam and sandy loam were overestimated as 12.2% and less estimated as 30%, respectively. However, $N_2O$ emissions were overestimated as 27.1% in the clay loam and 14.7% in the sandy loam from $N_2O$ gas samples collected once a week at the same time analyzing soil parameters. This modelling approach, based as it is well established and widely used soil measurements, has the potential to provide flux estimates from a much wider range of agricultural sites than would be possible by direct measurement of $N_2O$ emissions.

• Journal of Aquaculture
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• v.18 no.4
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• pp.225-230
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• 2005

This experiment was conducted to compare the effects of extruded pellets and raw fish-based pellet on olive flounder Paralichthys. olivaceus. Six diets were prepared for this study: two formulated extruded pellets (FEP1 & FEP2), three commercially available extruded pellets (CEP1, CEP2 & CEP3) and moist pellet (MP). Weight gain offish fed FEP1 and CEP3 were significantly higher (P<0.05) than those of fish fed FEP2, CEP1, CEP2 and MP, while that of fish fed MP was not significantly different (f<0.05) from those of fish fed the FEP2, CEP1 and CEP2. Feed efficiency of fish fed CEP2 was significantly lower (P<0.05) than those of fish fed FEP1, FEP2, CEP1, CEP3 and MP. There was no significant difference in protein efficiency ratio and hepatosomatic index between fish fed FEP1 and CEP3, and among fish fed FEP2, CEP1 and CEP2. There was no significant difference in condition factor among fish fed the FEP1 and CEP3, and between fish fed FEP2, CTP1 and MP. However, fish fed MP had a lower survival rate than fish fed the other five EP These results suggest that diet FEPl could be developed to replace MP for the owing stage of flounder without adverse effects on growth performance.

• Microbiology and Biotechnology Letters
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• v.43 no.2
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• pp.105-111
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• 2015

An alginate degrading enzyme from the Vibrio crassostreae PKA 1002 strain was used to hydrolyze the water extract of Sargassum thunbergii. To obtain the optimum degrading conditions for the S. thunbergii water extract, the mixture of the water extract and enzyme was incubated at 30℃ for 0, 3, 6, 12, and 24 h, and its alginate degrading ability was measured by reducing sugar and viscosity. A temperature of 30℃ for a period of 6 h was found to be the optimal condition for the enhancement of the alginate’s degrading ability. The pH of the enzymatic hydrolysate was not significantly different from that of the water extract. Overall lightness decreased, but redness and yellowness increased after enzymatic hydrolysis. Total phenolic compounds did not differ between the water extract and the enzymatic hydrolysate. DPPH radical scavenging activity and the reducing power of the enzymatic hydrolysate were lower than those of the water extract. However, the chelating effect of the enzymatic hydrolysate (80.08% at 5 mg/ml) was higher than that of the water extract (62.29%). These results indicate that the enzymatic hydrolysate possesses an anti-oxidant activity by way of the action of the chelating effect.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.436-447
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• 2004

Wetland plants have evolved specialized adaptations to survive in the low-oxygen conditions associated with prolonged flooding. The development of internal gas space by means of aerenchyma is crucial for wetland plants to transport $O_2$ from the atmosphere into the roots and rhizome. The formation of tissue with high porosity depends on the species and environmental condition, which can control the depth of root penetration and the duration of root tolerance in the flooded sediments. The oxygen in the internal gas space of plants can be delivered from the atmosphere to the root and rhizome by both passive molecular diffusion and convective throughflow. The release of $O_2$ from the roots supplies oxygen demand for root respiration, microbial respiration, and chemical oxidation processes and stimulates aerobic decomposition of organic matter. Another essential mechanism of wetland plants is downward water movement across the root zone induced by water uptake. Natural and constructed wetlands sediments have low hydraulic conductivity due to the relatively fine particle sizes in the litter layer and, therefore, negligible water movement. Under such condition, the water uptake by wetland plants creates a water potential difference in the rhizosphere which acts as a driving force to draw water and dissolved solutes into the sediments. A large number of anatomical, morphological and physiological studies have been conducted to investigate the specialized adaptations of wetland plants that enable them to tolerate water saturated environment and to support their biochemical activities. Despite this, there is little knowledge regarding how the combined effects of wetland plants influence the biogeochemistry of wetland sediments. A further investigation of how the Presence of plants and their growth cycle affects the biogeochemistry of sediments will be of particular importance to understand the role of wetland in the ecological environment.

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.249-259
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• 2014

Cryopreserving cells which are maintaining their viability are the very complex process. This study has been carried out in order to find the effects of cryopreservation steps and freezing media on the rates of viability of cryopreserved chicken primordial germ cells (PGCs). PGCs obtained from the germinal gonade of 5.5~6 day (stage 28) chick embryos of Korean Ogye (KO) and Commercial breeds (C), using the MACS method were suspended in a freezing medium containing a freezing and protecting agents (e.g. dimethyl sulfoxide (DMSO), ethylene glycol (EG) and propylene glycol (PG)). Gonads were harvested from stage 28 chick embryos and pooled in groups of 5, 10, 15, 20E embryos, contributing gonads to the cell suspension. The gonadal cells, including PGCs, were then frozen in 1 of the following cryoprotectant treatments : 2.5%, 5%, 10%, 15% and 0% cryoprotectant (DMSO, EG, PG) as a control. Effects of exposure to slow freezing and vitrification, with different concentrations of the cryoprotectant solution, were examined. After vitrification and slow freezing, survival rates of the frozen-thawed PGCs from the 10% EG plus FBS treatment were 85.63%, and 66.14% (p<0.05), respectively. The viability of PGCs after freeze-thawing was significantly higher for 10% EG plus FBS treatment than for 10% PG + FBS treatment (p<0.05) (85.63% vs 66.81%) by vitrification. This study established a method for preserving chicken PGCs that enables systematic storage and labeling of cryopreserved PGCs in liquid ($LN_2$) at a germplasm repository and ease of entry into a data base. In the future, the importance for this new technology is that poultry lines can be conserved while work is being conducted on improving the production of germline chimeras.