• Asian Journal of Turfgrass Science
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• v.9 no.4
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• pp.275-284
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• 1995

In this investigation, the accumulation mineralization and annual cycle of organic P has been studied in grassland ecosysterns of a Z japonica grassland and a M sinensis grassland on Mt. Kwanak. The basic models of the accumulation and mineralization for ash components of a grass-litter have been presented as the equations (1), (2), and (3). The equations (7)~(10) for organic P are derived from these basic concepts. There was a highty significant relationship between organic matter and organic P. The estimates between organic matter and organic P correlated very high significance. The parameter factors k or k' of mineralization of organic P for the Z. japonica and M sinensis asslands were k=0.412 or k'=0.292 and k=0.224 or k'=0.183, respectively. The time required for a cycle to be completed from organic P to inorganic P of 50, 95 and 99 % are 3.9, 16.7 and 27.8 years in the Z. japonica grassland and 4.1, 17.7 and 29.4 years in the M sinensis grassland. The annual P cycle formulae for mineralization were based on the equations (5), (11) and (12). Annual yields of mineralization for organic P in the steady state grasslands of Z. japonica and M sinensis were 0.407 and 0.504g /$m^2$, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.4
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• pp.588-609
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• 2018

The objective of this study is to provide information for improving the domestic particulate matter (PM) management. To achieve the study goal, we reviewed the past and current practice of PM management in the United States (US). Our review includes the assessment about the philosophical foundation and effectiveness of PM management, systematic program implementation to reach desirable PM conditions, and steady development of analytical tools including photochemical air quality models. We noticed that the current US PM management approach has improved annual $PM_{2.5}$ concentrations 22-48% in various parts of the US in the last 16 years. In addition, we analyzed strengths and difficulties in the past US PM management implementation. Based on the results of our analyses, we propose key elements to establish more effective domestic PM management in the future than now: steady investment in technological innovations and close-communications between local governments and the central government at various stages of PM management.

• Journal of Korean Society on Water Environment
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• v.39 no.3
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• pp.223-230
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• 2023

Harmful algae blooms have become a serious environmental problem in major river basins in Korea. They are known to produce various algal organic matters (AOMs) including intracellular organic matters (IOMs) and extracellular organic matters (EOMs). Generally AOMs cannot be easily removed by coagulation/flocculation process in conventional drinking water plants. AOMs produced by blue-green algae also include various toxins such as Microcystins, Anatoxin-a, and Saxitoxin known to have harmful effects on living organisms in aquatic environment. In this study, toxic effects of EOMs produced by three different algae species (Microcystis sp., Anabaena sp., and Oscillatoria sp.) on zebrafish were investigated using electroencephalography (EEG) recording method, a technology for recording brain activity. Electroencephalographic changes in zebrafish revealed that a low EOM had a negative effect on zebrafish compared to both Anabaena sp. and Oscillatoria sp. at 30 ppm EOM exposures. This result might be due to Microcystins present in EOMs produced by Microcystis sp. As a result of power spectrum density anallysis, exposure to EOMs produced by Microcystis sp. caused a state of vigilance in zebrafish. This EEG based toxicity test can be used to examine effects of harmful materials at low levels on living organisms in an aquatic system.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.51.2-51.2
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• 2017

Diffuse radio relics are often detected in merging galaxy clusters and are emitted by synchrotron process. Radio relics are believed to trace the shock waves in the intracluster medium induced by ram pressure during a major cluster merger. Radio halos and relics are found in approximately 50 galaxy clusters to date that are all in a state of merging. The rarest of these galaxy clusters contain pairs of relics of similar brightness as well as a radio halo. The massive galaxy cluster PLCKG287.0+32.9 belongs to this rare population and is the second most significant detection from the Planck SZ All-sky Survey. Perhaps even more intriguing is that the radio relics are observed at vastly different distances from the X-ray peak requiring a complex merging scenario. In this study, we use weak-lensing to peer deeper into the merging scenario by reconstructing the dark matter distribution. We relate the mass distribution to the radio, X-ray, and optical emissions to provide constraints for future simulations of the merger. Fitting an NFW profile to the tangential shear we infer the mass of the cluster and discuss its implications for the merging scenario.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.9
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• pp.1474-1480
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• 2018

Objective: Isoquinoline Alkaloids, derived from one plant (Macleaya cordata) can be an alternative when it is desired to increase performance in feedlot cattle. However, results on these nutritional additives in high energy diets in ruminants are still incipient in literature. In this context, the objective of this study was to evaluate performance and carcass traits of feedlot bulls supplemented with sanguinarine, the main alkaloid presents in Macleaya cordata in high energy density diets. Methods: Thirty-two crossbred Angus-Nelore bulls with mean initial body weight of $365{\pm}10kg$ and mean initial age of $11{\pm}3$ months were used. The experiment lasted 119 days, with 14 days of adaptation and 105 experimental days. Experimental diet consisted of 85% whole corn grains and 15% protein-vitamin-mineral nucleus and supplied ad libitum. Treatments consisted of a control diet (CON) and a diet with sanguinarine supplementation (SAN) at a dosage of 4 g of product sufficient to provide 6 mg of sanguinarine/d. Experimental design was completely randomized. Results: Dry matter intake, average daily gain and feed conversion were similar (p>0.05) between treatments. However, SAN group animals had higher carcass yield (p = 0.045) and were more efficient in the transformation of dry matter consumed in carcass gain (p = 0.046) than CON. In addition, haptoglobin, increased throughout feedlot duration meaning high challenge for the animals due to the diet, but this behavior was similar (p>0.05) between treatments. Conclusion: Sanguinarine produced positive results in relation to carcass yield and could be used as an additive for bulls fed diets receiving high energy density diet.

• Molecules and Cells
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• v.38 no.12
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• pp.1096-1104
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• 2015

Particulate $matter_{2.5}$ ($PM_{2.5}$) is notorious for its strong toxic effects on the cardiovascular, skin, nervous, and reproduction systems. However, the molecular mechanism by which $PM_{2.5}$ aggravates disease progression is poorly understood, especially in a water-soluble state. In the current study, we investigated the putative physiological effects of aqueous $PM_{2.5}$ solution on lipoprotein metabolism. Collected $PM_{2.5}$ from Seoul, Korea was dissolved in water, and the water extract (final 3 and 30 ppm) was treated to human serum lipoproteins, macrophages, and dermal cells. $PM_{2.5}$ extract resulted in degradation and aggregation of high-density lipoprotein (HDL) as well as low-density lipoprotein (LDL); apoA-I in HDL aggregated and apo-B in LDL disappeared. $PM_{2.5}$ treatment (final 30 ppm) also induced cellular uptake of oxidized LDL (oxLDL) into macrophages, especially in the presence of fructose (final 50 mM). Uptake of oxLDL along with production of reactive oxygen species was accelerated by $PM_{2.5}$ solution in a dose-dependent manner. Further, $PM_{2.5}$ solution caused cellular senescence in human dermal fibroblast cells. Microinjection of $PM_{2.5}$ solution into zebrafish embryos induced severe mortality accompanied by impairment of skeletal development. In conclusion, water extract of $PM_{2.5}$ induced oxidative stress as a precursor to cardiovascular toxicity, skin cell senescence, and embryonic toxicity via aggregation and proteolytic degradation of serum lipoproteins.

• Journal of Microbiology and Biotechnology
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• v.31 no.1
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• pp.8-15
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• 2021

More and more available fungal genome sequence data reveal a large amount of secondary metabolite (SM) biosynthetic 'dark matter' to be discovered. Heterogeneous expression is one of the most effective approaches to exploit these novel natural products, but it is limited by having to clone entire biosynthetic gene clusters (BGCs) without errors. So far, few effective technologies have been developed to manipulate the specific large DNA fragments in filamentous fungi. Here, we developed a fungal BGC-capturing system based on CRISPR/Cas9 cleavage in vitro. In our system, Cas9 protein was purified and CRISPR guide sequences in combination with in vivo yeast assembly were rationally designed. Using targeted cleavages of plasmid DNAs with linear (8.5 kb) or circular (8.5 kb and 28 kb) states, we were able to cleave the plasmids precisely, demonstrating the high efficiency of this system. Furthermore, we successfully captured the entire Nrc gene cluster from the genomic DNA of Neosartorya fischeri. Our results provide an easy and efficient approach to manipulate fungal genomic DNA based on the in vitro application of Cas9 endonuclease. Our methodology will lay a foundation for capturing entire groups of BGCs in filamentous fungi and accelerate fungal SMs mining.

• Animal Bioscience
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• v.36 no.1
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• pp.108-118
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• 2023

Objective: The objective of this experiment was to determine the net energy (NE) value of 6 wheat bran and 1 wheat shorts by indirect calorimetry and establish the NE prediction equations of wheat bran fed to growing barrows. Methods: Forty-eight growing barrows (28.5±2.4 kg body weight) were allotted in a completely randomized design to 8 dietary treatments that included a corn-soybean meal basal diet, 6 wheat bran diets and 1 wheat shorts diet. The inclusion level of wheat bran or wheat shorts in diets is 30%. Results: The addition of wheat bran reduced the apparent total tract digestibility (ATTD) of nutrients (p<0.05). The ATTD of gross energy, crude protein (CP) and dry matter (DM) in the wheat shorts were greater than that in the wheat bran. Addition of wheat bran or wheat shorts had no effect on total heat production and fasting heat production. The NE of wheat bran was negatively correlated with neutral detergent fiber (r = -0.84; p<0.05) and acid detergent fiber (r = -0.83; p<0.05), while it was positively correlated with CP (r = 0.92; p<0.01). The NE values of wheat bran ranged from 6.79 to 8.15 MJ/kg DM, and the NE value of wheat shorts was 12.47 MJ/kg DM. The ratio of NE to metabolizable energy for wheat bran fed to growing pigs was from 66.0% to 71.7%, whereas the value for wheat shorts was 83.7%. Conclusion: The NE values of wheat bran ranged from 6.79 to 8.15 MJ/kg DM, and the NE value of wheat shorts was 12.47 MJ/kg DM. The NE value of wheat bran can be well predicted based on energy content and proximate analysis.

• Animal Bioscience
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• v.37 no.6
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• pp.1085-1095
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• 2024

Objective: The main objective of this study was to determine available energy and nutritional digestibility of extruded cereals and the effect of extrusion on the nutritional value of feed ingredients, aiming to provide scientific basis for efficient application of extrusion in the diets of growing pigs. Methods: In Exp. 1, 48 crossbred growing pigs (Duroc×Landrace×Yorkshire) with an initial body weight (BW) of 34.6±2.2 kg were selected and fed with eight diets (non-extrusion or extrusion) to determine the digestible energy (DE), metabolizable energy (ME), and nutrients digestibility. Eight diets included extruded grains (barley, wheat, sorghum, or broken rice), while four had unprocessed grains. In Exp. 2, 9 diets were formulated including 4 cereals with extrusion or non-extrusion and a N-free diet. In addition, 9 growing pigs (BW = 22.3±2.8 kg) were fitted with T-cannula in the distal ileum and arranged in a 9×6 Youden square design. Results: Results show that apparent total tract digestibility of gross energy, dry matter, organic meal, ether extract, neutral and acid detergent fiber was not affected by the extrusion process and there was no interaction between cereal type and extrusion treatment on DE, ME. However, the apparent total tract digestibility for crude protein (CP) increased markedly (p<0.05). The standardized ileal digestibility (SID) of all amino acids (AA) except for leucine remarkably increased by extrusion (p<0.05). There was an interaction on the SID of arginine, leucine, isoleucine, methionine, phenylalanine, cystine, and tyrosine in growing pigs between type of grain and extrusion treatment (p<0.05). Conclusion: Extrusion increased the ileal digestibility of CP and most AA in cereals, however, the DE and ME of cereals were not affected in growing pigs.

• Journal of the Korean Chemical Society
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• v.47 no.3
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• pp.265-272
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• 2003

This study investigated the types of analogies that 7th graders generated to explain three states of matter, the difference of analogies by achievement level, and the misconceptions that might be induced from the analogies. The results revealed that many students made the enriched and storytelling analogies with concrete materials or events from their everyday experiences. However, they made analogies without considering causal relationship such as the change of particular arrangement based on latent heat or molecular movement. The students of high achievement level considered the arrangement and the movement of molecules and made the enriched and storytelling analogies more than the students of low achievement level. The students made the analogies that might induce misconceptions such that the molecules don't move in solid state or the particles could be changed according to the states.