• 한국작물학회지
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• 제47권2호
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• pp.95-101
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• 2002

To investigate the changes in the composition and pool size of nitrogen metabolites under drought stress, white clover (Trifolium repens L.) were exposed to -0.04MPa (well-watered, control) or to -0.12MPa (drought-stressed) of soil water potential during 28 days. Dry weight of leaves in drought-stressed plants was remarkably decreased by 45% and 74% within 14 days and 28 days, respectively, compared with control. For nitrate concentration after 28 days of treatment, a significant difference (1.6 times higher in drought-stressed plants) was observed only in stolon. NH$_3$-NH$_4$$^{+}$ concentration in all three organs of drought-stressed plants linearly increased to more than 1.6 times higher level at 28 day when compared to the initial level (day 0), while the increasing rate in control was much less than that of drought-stressed plants. Proline concentrations in drought-stressed plants remarkably increased and reached to 7, 13 and 17 times higher level at 28 day compared to control. Protein concentration in leaves of drought-stressed plants tended to decrease, while it slightly increased during the first 14 days and reached a plateau afterward in control. There was not significant difference in the proteins concentration of stolon and roots throughout experimental period. On SDS-PAGE analysis, two major proteins specifically induced by drought stress (16-kD and 18-kD) were detected in stolon.n.

• 한국환경농학회지
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• 제21권1호
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• pp.74-79
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• 2002

Two consecutive green house experiments were carried out to examine the effect of Azospirillum spp. inoculation on growth, nitrogen and phosphorus accumulation in maize plants grown in pots. There were eight treatments including an uninoculated control and Azospirillum strains OAD-3, OAD-9, AZ-22, AZ-8, AZ-9, Azospirillum brasilense BR-11001 and Azospirillum lipoferum BR-11080. The inoculated plants showed higher values in each of the following measurements; plant height, total dry mass and nitrogen and phosphorus accumulation in shoot when compared to the uninoculated control plants in two consecutive experiments conducted in the same soil. Among Azospirillum strains, Azospirillum sp. OAD-3 inoculated plants showed higher nitrogen accumulation by 44.5% and 45.1%, total dry mass by 48.6% and 66.9% in two consecutive experiments respectively. The nitrogen concentration in the maize plants was not changed significantly in the first experiment, however it increased significantly in the second experiment due to Azospirillum inoculation. In addition, Azospirillum sp. OAD-9 and A. brasilense BR-11001 also proved to be effective with respect to total dry mass, total nitrogen accumulation and total phosphorus accumulation. The nitrogen concentrations in maize plants were increased in the second experiment due to Azospirillum inoculation.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.599-604
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• 2000

A laboratory scale extended aeration system was installed to study the effects of DO control and intermittent aeration on energy saving and nitrogen removal. The sensors of pH, DO, ORP, MLSS, and WT were installed in the aerator to monitor them and automatically control DO concentration as 2 mg/$\ell$. In the conditions showing nitrate knee on the ORP curves, nitrogen removal rates were kept over 91%. A 72.4 % of energy saving was achieved by intermittent aeration comparing with continuous aeration.

• Asian-Australasian Journal of Animal Sciences
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• 제25권9호
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• pp.1269-1275
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• 2012

An experiment was conducted to study the effect of soluble protein supplements on concentration of soluble non-ammonia nitrogen (SNAN) in the liquid phase of ruminal (RD) and omasal digesta (OD) of Korean native steers, and to investigate diurnal pattern in SNAN concentration in RD and OD. Three ruminally cannulated Korean native steers in a $3{\times}3$ Latin square design consumed a basal diet of rice straw and corn-based concentrate (control), and that supplemented (kg/d DM basis) with intact casein (0.24; IC) or acid hydrolyzed casein (0.46; AHC). Ruminal digesta was sampled using a vacuum pump, whereas OD was collected using an omasal sampling system at 2.0 h intervals after a morning feeding. The SNAN fractions (free amino acid (AA), peptide and soluble protein) in RD and OD were assessed using the ninhydrin assay. Concentrations of free AA and total SNAN in RD were significantly (p<0.05) lower than those in OD. Although free AA concentration was relatively high, mean peptide was quantitatively the most important fraction of total SNAN in both RD and OD, indicating that degradation of peptide to AA rather than hydrolysis of soluble protein to peptide or deamination may be the most limiting step in rumen proteolysis of Korean native steers. Diurnal variation in peptide concentration in OD for the soluble protein supplemented diets during the feeding cycle peaked 2 h post-feeding and decreased thereafter whereas that for the control was relatively constant during the entire feeding cycle. Diurnal variation in peptide concentration was rather similar between RD and OD.

• 한국임상수의학회지
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• 제32권5호
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• pp.426-432
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• 2015

본 연구는 임상형 혹은 준임상형 자궁내막염에 이환된 젖소와 자궁내막염이 발생되지 않은 젖소 사이에 분만 전 후 기간 동안 혈액 대사물질의 농도를 비교하였다. 분만 전 4주, 분만 후, 분만 1, 2, 4, 6주 후 혈액을 채취하였으며, 혈청 분리 후 calcium, magnesium, non-esterified fatty acids (NEFAs), total cholesterol, albumin, urea nitrogen, ${\beta}$-hydroxybutyrate (BHBA), aspartate aminotransferase (AST), ${\gamma}$-glutamyltransferase, glucose 및 phosphorus 농도를 측정하였다. 분만 후 4주에, 임상형 혹은 준임상형 자궁내막염 발생 유무에 따라 대조군(n = 104), 임상형 자궁내막염군(n = 66) 및 준임상형 자궁내막염군(n = 37)으로 구분하였다. Calcium과 magnesium 농도는 실험 전 기간에 걸쳐 임상형 자궁내막염군이 대조군과 준임상형 자궁내막염군에 비해 낮았으나(p < 0.05 to 0.0001), NEFAs 농도는 실험전 기간에 걸쳐 임상형 자궁내막염군이 대조군에 비해 높았다(p < 0.01). Total cholesterol 농도는 분만 전 및 분만 후 기간 중 임상형 자궁내막염군이 대조군과 준임상형 자궁내막염군에 비해 낮았다(p < 0.05 to 0.001). Albumin 농도는 분만 후 기간 동안 임상형 자궁내막염군이 대조군과 준임상형 자궁내막염군에 비해 낮았다(p < 0.05 to 0.001). Urea nitrogen 농도는 분만 후 4주 및 6주에 임상형 자궁내막염군이 대조군과 준임상형 자궁내막염군에 비해 낮았다(p < 0.01). 분만 후 1주에, BHBA 농도는 임상형 자궁내막염군이 대조군에 비해 높았으나(p < 0.01), AST 농도는 임상형 자궁내막염군과 준임상형 자궁내막염군이 대조군에 비해 높았다(p < 0.05). 결론적으로, 분만 후 혈청 calcium, magnesium, total cholesterol, albumin 및 urea nitrogen 농도의 감소와 NEFAs, BHBA 및 AST 농도의 증가가 임상형 자궁내막염의 발생과 관련되었으며, 이것은 전환기 중의 균형 잡힌 영양의 중요성을 제시한다.

• 생물환경조절학회지
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• 제19권4호
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• pp.257-265
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• 2010

본 연구는 수경재배시 산호수 생육과 개화를 증진시키기 위한 적절한 질소농도 및 공급시기를 구명하기 위해 수행하였다. 질소농도가 120, 150, 180, $210mg{\cdot}L^{-1}$로 조성된 양액을 1년생과 2년생 Ardisia pusilla에 휴면기(10월~3월) 제외한 기간 급액(ED; except dormancy), 생육 전기간 급액(TG; total growth)으로 나누어 처리하였다. 묘령 및 급액기간에 따른 생육을 비교한 결과 1년생 묘는 급액기간에 관계없이 질소농도 $150mg{\cdot}L^{-1}$ 이상 처리구에서 우수하였다. 2년생묘는 TG기간 동안 급액한 처리구가 ED기간을 제외하고 급액한 처리구들보다 대체적으로의 생육이 훨씬 우수하였으며, 특히 TG-$150mg{\cdot}L^{-1}$의 생육이 가장 좋았다. 개화 후 엽의 무기성분 함량을 측정한 결과 묘령에 관계없이 전체적으로 양액내 질소농도가 증가할수록 T-N의 함량은 높아지고 K, Ca, Mg, P의 함량은 약간 낮아지거나 차이가 거의 없었다. 그러나, 1년생 ED-210 처리구는 모든 처리구 중 Ca와 Mg 함량은 가장 높은 반면 K와 P의 함량은 가장 낮았으며 개화수도 적었다. 즉, 질소농도가 $210mg{\cdot}L^{-1}$ 이상으로 조성되면 오히려 생육이나 개화수가 감소되는 것으로 보아 1년생 산호수는 생장 및 개화를 위해 TG-150으로 처리하고, 2년생 묘는 TG-180이 수경재배시 적정한 급액시기 및 질소농도로 판단된다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권3호
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• pp.171-178
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• 2004

Glucose alone was found to be the most effective carbon source for producing compactin. An initial glucose concentration of 40 g/L gave the highest compactin concentration of 250mg/L. Among the various nitrogen sources, when 5g/L of pharmamedia and soybean meal as the sole nitrogen source were used, respectively, the compactin concentration was higher than 250mg/L. Especially, in the case of the mixture of 6 g/L of pharmamedia and 8 g/L of soybean meal, the compactin concentration was 400mg/L. To select the best surfactant for effective compactin production, various surfactants were investigated. When Triton X-100 was used, the maximum compactin concentration was 445mg/L. With the initial concentration ranging from 1.5 to 2.0 g/L, the compactin concentration was the highest at 465-450mg/L. The cell concentration was similar to that of the control without the addition of Triton X-100. On the other hand, when the above 4.0 g/L of Triton X-100 were used, the cell concentration decreased. Using the based results, the continuous fed-batch cultures by adding the Triton X-100 were carried out for 10 days in an air-lift bioreactor. When 1.5 g/L of Triton X-100 was added to the culture broth at 0, 4, and 8 days of culture, respectively, the compactin production was increased with the increase of culture time. The maximum compactin concentration after 10days of culture was 1,200mg/L, which was about 2.0-fold higher than that of the control without the addition of Triton X-100.

• 한국유체기계학회 논문집
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• 제18권2호
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• pp.43-47
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• 2015

As water quality regulations have tightened, many studies to improve wastewater treatment efficiency have been performed. In this study, magnetite powder was used to maintain a high concentration of MLSS in lab-scale wastewater treatment system. After magnetite powder injection, MLSS concentration was above 8,000 mg/L and it was 3.2 times higher than control group(2,500 mg/L). In addition, nitrogen removal efficiency and phosphorus removal efficiency comparing with the control group was increased 20.5% and 11%, respectively.

• 한국물환경학회지
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• 제23권4호
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• pp.512-517
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• 2007

The limiting nutrient of eutrophication in freshwater bodies in Korea was examined and the phosphorus concentration standard for sewage treatment effluent was discussed. The weight ratio of N/P in 13 major reservoirs showed the range of 18 to 163, which implies phosphorus is more limited than nitrogen for algal growth. In the correlation analysis phosphorus showed higher correlation with chlorophyll-a concentration than with nitrogen. In the algal bioassay phosphorus spike test enhanced algal growth in all 25 samples of five reservoirs, while nitrogen was found to co-limit only in four samples. It confirms that phosphorus is the only limiting nutrient for eutrophication in Korean reservoirs. As many reservoirs are eutrophic in Korea, phosphorus control is critical for the management of water quality. The phosphorus standard of sewage treatment effluent in Korea was compared with other countries, and it can be concluded that phosphorus standard is too high to be effective in eutrophication control and a lower phosphorus standard is essential for the water quality improvement.

• Asian-Australasian Journal of Animal Sciences
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• 제15권6호
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• pp.821-827
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• 2002

The purpose of this study was to evaluate the effect of protected fat and heat-extruded soybean meal on the lactation performance of Holstein cows. Twenty-four cows, consisting of 20 lactating cows and 4 rumen-fistulated dry cows, were randomly allocated into four groups with 5 lactating cows and 1 fistulated cow in each group. A replicated 4${\times}$4 Latin square design with four 21 day periods, including 14 days of adaptation and 7 collection days within each period was employed. The experiment was a 2${\times}$2 arrangement, with or without heat-extruded soybean meal and protected fat inclusion. The dietary treatments consisted of supplements of (a) soybean meal (the control), (b) heat-extruded soybean meal, (c) protected fat, and (d) heat-extruded soybean meal and protected fat. The results showed that there were no significant differences in feed intake, milk yield, milk protein content, milk lactose content and body weight change between the dietary treatments. However, cows supplemented with protected fat showed a significantly increased (p<0.05) milk fat yield, 3.5% FCM and total solid yield. The increase in undegradable intake protein (UIP) via heat extruded soybean meal supplement significantly decreased the urea nitrogen concentration in the blood (p<0.05). Dietary fat inclusion significantly increased the blood cholesterol concentration (p<0.01) and decreased the ruminal pH value (p<0.01). Increased dietary UIP significantly decreased the ammonia nitrogen concentration in the rumen (p<0.01), but did not significantly influence the pH and VFA molar percentage in the rumen. It appears that dietary protected fat inclusion could improve milk fat and solid content. Increased dietary undegradable intake protein through heat extruded soybean meal did not improve milk yield. But it could alleviate the adverse effect of decreased milk protein due to dietary fat supplementation. Increased UIP could also decrease the ammonia nitrogen concentration in the rumen and plasma urea nitrogen concentration in the blood.