• Asian-Australasian Journal of Animal Sciences
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• v.20 no.4
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• pp.543-549
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• 2007

Two experiments were conducted to investigate the effects of disodium fumarate on the in vitro rumen fermentation profiles of different substrates and microbial communities. In experiment 1, nine diets (high-forage diet (forage:concentrate, e.g. F:C = 7:3, DM basis), medium-forage diet (F:C = 5:5, DM basis), low-forage diet(F:C = 1:9, DM basis), cracked corn, cracked wheat, soluble starch, tall elata (Festuca elata), perennial ryegrass and rice straw) were fermented in vitro by rumen microorganisms from local goats. The results showed that during 24 h incubations, for all substrates, disodium fumarate increased (p<0.05) the gas production, and tended to increase (p<0.10) the acetate, propionate and total VFA concentration and decrease the ratio of acetate to propionate, whereas no treatment effect was observed for the lactate concentration. The apparent DM loss for tall elata, perennial ryegrass and rice straw increased (p<0.05) with the addition of disodium fumarate. With the exception of tall elata, perennial ryegrass and rice straw, disodium fumarate addition increased the final pH (p<0.05) for all substrates. In experiment 2, three substrates (a high-forage diet, a medium-forage diet and a high concentrate diet) were fermented by mixed rumen microbes in vitro. A polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique was applied to compare microbial DNA fingerprints between substrates at the end of 24 h incubation. The results showed that when Festuca elata was used as substrate, the control and disodium fumarate treatments had similar DGGE profiles, with their similarities higher than 96%. As the ratio of concentrate increased, however, the similarities in DGGE profiles decreased between the control and disodium fumarate treatment. Overall, these results suggest that disodium fumarate is effective in increasing the pH and gas production for the diets differing in forage: concentrate ratio, grain cereals and soluble starch, and in increasing dry matter loss for the forages (tall elata, perennial ryegrass and rice straw) in vitro, whereas its effect on changes of ruminal microbial community may largely depend on the general nature of the substrate.

• Korean Journal of Environment and Ecology
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• v.30 no.5
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• pp.803-809
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• 2016

In order to elucidate the ecological responses of B. latissimum under global warming situation and prepare the conservation measures, we cultivated the plant within control(ambient $CO_2+$ambient temperature) and treatment(elevated $CO_2+$elevated temperature) from 2010 to 2011. Rising $CO_2$ concentration was treated with 2 times and temperature increased with $2.0^{\circ}C$ above than control. As a result, Growth response has received more the effect of $CO_2+$Temperature rising than light, moisture, nutrients, and it was grow well in $CO_2+$temperature rise sphere when many nutrients, and it was grow well in $CO_2+$temperature rise sphere when many nutrients. No. of leaves were many number in the treated group compared to the control at a low light gradient and high nutrient gradient, leaf width was narrow in the treatment compared to the control in the middle gradient of light and nutrients. Shoot length, petiole length, lamina length was no difference between control and $CO_2+$temperature rise sphere. Based on the results of this study, in order to preserve the B. latissimum in future climate, we should be supply of nutrients(containing ${NH_4}^+$, $NO_3$, $P_2O_5$, $K_2O$, etc.) in the habitat of the B. latissimum, and must ensure that the habitat of B. latissimum is not destroyed. Also, We should be find similar area with habitat of the B. latissimum, restoring, expanding.

• Membrane Journal
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• v.31 no.4
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• pp.253-261
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• 2021

Solutions to water pollution, global warming, and climate change have been currently discussed. Pressure retarded osmosis (PRO) using a difference in salt concentration between two fluids is proposed to meet the demand for clean water and produce eco-friendly energy. Although PRO has been researched continuously, it has not been commercialized yet due to limitations such as lack of technology and the high price of membranes. Meanwhile, the membrane is one of the most significant parts of the PRO engine and salinity gradient power (SGP) technology. Research continues to technologically develop graphene oxide membranes and nanocomposite membranes used in salinity gradient power generation. Studies on efficient membranes, solvents, and solutes are active to enable high energy efficiency of the osmotic heat engine even at low temperatures of waste. Studies have been conducted on reducing internal concentration polarization and increasing power density by using membranes with balanced permeability and selectivity. In this review, dealing with these studies, we discuss the types of PRO membranes, theoretical modeling of technologies through efficient membranes, and other technologies to develop the process efficiency.

• Journal of Environmental Health Sciences
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• v.23 no.1
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• pp.18-27
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• 1997

The isolation, morphological study and growth characteristics of the algae were investigated from Lake Chuam. The isolated algae were applied the Agal Growth Potential test. The method of isolation and purification of the algae were used to Agar plating(AP), nutrient enrichment(NE), dilution(DI) and micro capillary technique(MC). Total isolated algae were 21 species. They were composed of Cyanophyceae, Dinophyceae, Bacillariophyceae, Euglenophyceae and Chlorophyceae. The numbers of algal strain by isolation technique were highest in dilution(21 species), and those of the rests were showed in order of NE > MC > AP. The sizes of isolated Selenastrum and Scenedesmus were $1.8\pm 1.4 \mu m$, $3.3\pm 0.9 \mu m$ in diameter and $6.4\pm 2.3 \mu m$, $13.6\pm 1.9 \mu m$ in length respectively. The morphology of isolated algae and NIES-collection strain was very similar each other, but the size was smaller isolated algae than that of NIES-collection. The optimum culture condition of isolated Selenastrum and Scenedesmus was about 30$\circ$C(25$\circ$C-35$\circ$C) in temperature and the maximum growth was appeared between 7,000 lux and 8,000 lux in the light intensity. The comparison of $\mu$(specific growth rate) on the concentration of nutrients such as nitrate and phosphate, isolated Selenastrum was appeared maximum it at 1.0 mg $NO_3-N/l$ but NIES-collection strain was showed 95% of maximum it at same nitrate concentration. Maximum g of isolated algae and NIES-collection strain in Scenedesmus onto nitrate concentration were very similar with the result of selenastrum. The specific growth rates of isolated algae and NIES-collection strain on the gradient concentration of phosphate were showed 0.72/day and 0.70/day at 0.02 mg $PO_4-P/l$ in Selenastrum but those of Scenedesmus were appeared 0.61/day and 0.57/day at same concentration $PO_4-P$.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1B
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• pp.73-81
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• 2009

This paper presents a numerical investigation of the impact of the secondary currents on solute transport in open-channel flows. The RANS model with Reynolds stress model is used for flow modeling, and the GGDH(generalized gradient diffusion hypothesis) model is used to close the scalar transport equation. Using the developed model, the impact of secondary currents on solute transport in open channel flows over smooth-rough strip is investigated. Through numerical experiments, the secondary currents are found to affect the solute spreading, leading a movement of the position of the peak concentration and a skewed distribution of solute concentration. Due to the lateral flow of secondary currents near the free surface, the concentration at the rough strip is found to be larger than that at the smooth strip bed. The solute at the rough strip is more rapidly transported than smooth bed. A magnitude analysis of the solute transport rate in scalar transport equation is also carried out to investigate the effect of secondary currents and scalar flux on the concentration distribution.

• The Korean Journal of Physiology
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• v.20 no.2
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• pp.225-235
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• 1986

Effects of anions on p-Aminohippurate (PAH) transport across the basolateral membrane (BLM) were studied. Basolateral membrane vesicles were isolated from rabbit renal cortex by using a self-orienting Percoll-gradient centrifugation and $Mg^{2+}-precipitation$. The characteristics of the membrane vesicles was examined by marker enzyme activity, membrane orientation and transport studies. The Na-K-ATPase activity in the fraction containing BLM vesicles was enriched 9·fold, and the alkaline phosphatase activity in the fraction containing BBM vesicles was increased 9-fold, compared with those of the homogenate. The transport properties of the two membrane preparations were studied by a rapid filtration technique. The uptake of PAH by BLM was sensitive to changes in medium osmolarity and inhibited by probenecid. When the uptake of $50{\mu}M$ PAH in voltage-clamped BLM vesicles was determined in the presence of various anions in the incubation medium, cis inhibitions by $SO_4\;and\;SSO_3$ were observed in the presence of sodium gradient (out>in). Sodium-dependent PAH uptake was inhibited competitively by external $SO_4$ PAH uptake in BLM vesicles loaded with 20 mM acetate and $SO_4\;or\;200\;{\mu}M$ PAH was significantly stimulated as compared with unloaded vesicles. The extent of trans-stmulation of PAH uptake by $SO_4$. was increased with the inside concentration of $SO_4$. This trans-stimulatory effect by $SO_4$, was observed to be additive in the presence of Na gradient and completely inhibited by 2 mM probenecid and 1 mM SITS. These results demonstrate that PAH/anion exchange is present in BLM of renal cortex and in this exchange mechanism inorganic as well as organic anions are involved as substrates.

• Atmosphere
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• v.30 no.4
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• pp.377-390
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• 2020

Not only emissions, but also atmospheric circulation is a key factor that affects local particulate matters (PM) concentrations in Korea through ventilation effects and transboundary transports. As part of the atmospheric circulation, air stagnation especially adversely affects local air quality due to weak ventilation. This study investigates the large-scale circulation related to air stagnation over Korea during winter and projects the climate change impacts on atmospheric patterns, using observed PM data, reanalysis and regional climate projections from HadGEM3-RA with Modified Korea Particulate matter Index. Results show that the stagnation affects the PM concentration, accompanied by pressure ridge at upper troposphere and weaken zonal pressure gradient at lower troposphere. Downscaling using HadGEM3-RA is found to yield Added-Value in the simulated low tropospheric winds. For projection of future stagnation, SSP5-8.5 and SSP1-2.6 (high and low emission) scenarios are used here. It has been found that the stagnation condition occurs more frequently by 11% under SSP5-8.5 and by 5% under SSP1-2.6 than in present-day climate and is most affected by changes in surface wind speed. The increase in the stagnation conditions is related to anticyclonic circulation anomaly at upper troposphere and weaken meridional pressure gradient at lower troposphere. Considering that the present East Asian winter monsoon is mainly affected by change in zonal pressure gradient, it is worth paying attention to this change in the meridional gradient. Our results suggest that future warming condition increase the frequency of air stagnation over Korea during winter with response of atmospheric circulation and its nonlinearity.

• Journal of the Korean Ceramic Society
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• v.42 no.3 s.274
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• pp.211-217
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• 2005

[ $Zn_{1-x}Co_{x}O$ (x=0-0.3) films were grown on Corning 7059 glasses by asymmetrical bipolar pulsed dc magnetron sputtering. The c-axis orientation along (002) plane was enhanced with increasing Co concentration. The $Zn_{1-x}Co_{x}O$ films are grown with fibrous grains of tight dome shape. The transmittance spectra measured from UV-visible showed that sp-d exchange interactions and typical d-d transitions become activated with increasing Co concentration. The electrical resistivity of $Zn_{1-x}Co_{x}O$ films increased with increasing Co concentration, especially it increased greatly at $30at\% Co. X-ray photoelectron spectroscopy and alternating gradient magnetometer analyses indicated that no Co metal cluster is formed and the ferromagnetic properties are exhibited. The low electrical resistivity and room temperature ferromagnetism of $Zn_{1-x}Co_{x}O$ thin films suggested the possibility of the application to Diluted Magnetic Semiconductors (DMSs).

• Food Science of Animal Resources
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• v.25 no.4
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• pp.478-482
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• 2005

Bovine k-casein macropeptide was prepared by adding TCA (3, 6, and $12\%$) treatment after chymosin reaction. Each TCA soluble macropeptide was fractionated into five peak by ion exchange column chromatography. In proportiion to TCA concentrations, the ratio of peak area showed different the elution pattern. At the 6 and $12\%$ TCA concentration, area ratio of P-I which did not content carbohydrates was decreased to 19.9 and $17.0\%$ of total peak area respectively. The area of P-III was changed from $10.2\%\;to\;26.2\;and\;13.2\%$ when the TCA concentration was increased from 3 to 6 and $12\%$ Cholera toxin binding activity of k-casein macropeptide eluted at $0.17\~0.18M$ NaCl gradient was not inhibited by 6 and $12\%$ TCA treatments. The use of $6\%$ TCA as extraction buffer was feasible and led to an effective separation of the peak III.

• Korean Journal of Ecology and Environment
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• v.37 no.2 s.107
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• pp.193-204
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• 2004

This study was conducted to evaluate both temporal and spatial dynamics of phytoplankton community and environmental parameters in a newly made reclaimed esturine lake (L. Hwaong). Monthly sampling was conducted at 4 sites covering the longest transect of longitudinal gradient of the lake from June to November, 2002. Total 5 classes 8 orders 26 families 83 genus 192 species were identified at all study sites during the study period. Phytoplankton total cell density ranged 24${\sim}$ 1,882 cells $mL^{-1}$ and highly varied both temporally and spatially. Total cell density was significantly related with salinity, pH, BOD, COD, SS, TN and TP concentration. Diatom density also was significantly correlated with salinity, SS, BOD, COD and TN concentration, Although there was spatial difference, a longtudinal gradient appeared in phytoplankton cell density, Chl-a, TN and TP concentration from the mouth of river in June and August. In conclusion, phytoplakton community structure was dominated by diatoms (Bacillariophyceae), and appeared to be largely influenced by salinity, precipitation, and nutrients during the summer and the fall.