• 한국대기환경학회지
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• 제28권1호
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• pp.94-104
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• 2012

The purpose of this research is to quantify the compliance of on-road emission from a light duty diesel vehicle, based on a comparison to emission regulation standard. $NO_x$, CO and THC emissions were measured using a portable device on a selected real-world driving route with a length of approximately 22 km. On-road measurements were repeated by 10 times on a same route to reflect variability in traffic conditions. A test route was divided into 22 road links with length of 1 km to analyze emission results with higher spatial resolution. The average emissions of $NO_x$, CO and THC over total travel distance, which is approximately 220 km, were quantified to be in compliance with emission regulation standards. Under higher spatial resolution, $NO_x$ concentration exceeded a standard in 92 links out of 220 links. The extended time in stop period and the stop-and-go driving cycle were identified as two important reasons for increased $NO_x$ emissions in observed cases. Heavy traffics showed higher $NO_x$ emissions than free flow. These results indicate that the real-world vehicle emissions might exceed the compliance level associate with traffic conditions. Another interesting observation of this research is that the on-road emission characteristics can be independent to the average speed of road links with higher spatial resolution. Variability in on-road emission might not be fully described by solely relying on an average speed, because variability in traffic conditions and road conditions can influence on real-world vehicle emissions.

• Genes and Genomics
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• 제40권11호
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• pp.1199-1211
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• 2018

Soil acidification is one of major problems limiting crop growth and especially becoming increasingly serious in China owing to excessive use of nitrogen fertilizer. Only the STOP1 of Arabidopsis was identified clearly sensitive to proton rhizotoxicity and the molecular mechanism for proton toxicity tolerance of plants is still poorly understood. The main objective of this study was to investigate the transcriptomic change in plants under the low pH stress. The low pH as a single factor was employed to induce the response of the wheat seedling roots. Wheat cDNA microarray was used to identify differentially expressed genes (DEGs). A total of 1057 DEGs were identified, of which 761 genes were up-regulated and 296 were down-regulated. The greater percentage of up-regulated genes involved in developmental processes, immune system processes, multi-organism processes, positive regulation of biological processes and metabolic processes of the biological processes. The more proportion of down-regulation genes belong to the molecular function category including transporter activity, antioxidant activity and molecular transducer activity and to the extracellular region of the cellular components category. Moreover, most genes among 41 genes involved in ion binding, 17 WAKY transcription factor genes and 17 genes related to transport activity were up-regulated. KEGG analysis showed that the jasmonate signal transduction and flavonoid biosynthesis might play important roles in response to the low pH stress in wheat seedling roots. Based on the data, it is can be deduced that WRKY transcription factors might play a critical role in the transcriptional regulation, and the alkalifying of the rhizosphere might be the earliest response process to low pH stress in wheat seedling roots. These results provide a basis to reveal the molecular mechanism of proton toxicity tolerance in plants.

• Asian-Australasian Journal of Animal Sciences
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• 제24권10호
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• pp.1393-1398
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• 2011

Four 4-month old Charolais${\times}$Dorset male sheep (initial liveweight $25.0{\pm}1.1\;kg$), fitted with rumen and abomasal fistulas and nourished by total intragastric infusions, were used to study the relationships between methionine (Met) supply, nitrogen (N) retention and plasma insulin-like growth factor-I (IGF-I). Four graded levels of Met, i.e. 0 g/16 g N, 1.76 g/16 g N, 3.52 g/16 g N and 7.04 g/16 g N, were infused into abomasums as experimental treatments. The sheep and treatments were allocated in a $4{\times}3$ incomplete Latin square design (Yudon square design). The experiment lasted 3 periods and each period was 10 days. Quadratic correlations were found between Met level (x, g/16 g N) and N retention (y, g/d): y = $-0.03x^2$+0.41x+2.62, $r^2$ = 0.66, n = 12, p = 0.008, and between methionine level (x, g/16 g N) and plasma IGF-I concentration (y, ng/ml): y = $0.80x^2$-4.53x+190.24, $r^2$ = 0.51, n = 12, p = 0.009. No significant correlation was found between plasma IGF-I (x, ng/ml) and N retention (y, g/d) (p>0.05). It was concluded that Met level had a significant influence on N retention and plasma IGF-I concentration whereas IGF-I might not be an important mediator in the regulation of N metabolism by Met in growing sheep nourished by total intragastric infusions.

• Journal of Animal Science and Technology
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• 제57권5호
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• pp.20.1-20.8
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• 2015

Background: In order to prepare for the regulation about the limit of manure production, the status of manure management and the amount of nutrients in the compost discharged from Hanwoo breeding farm shall be known. This study aimed to find the practical amount of nutrients (volatile solids, VS; total nitrogen, T-N; total phosphorus, T-P) in manure, and compost samples collected from 40 Hanwoo breeding farms and the loss of the nutrients was calculated during the composting period, which supports to develop nutrient loading coefficients (NLCs) for each nutrient. Results: Although the addition of bedding materials for composting caused the increase of the VS amount before composting, the comparison of VS, N, and P amounts in between manure and compost showed the lower VS by 4 % as well as T-N and T-P amounts by 69 and 40 %, respectively, of which values were corresponded with the NLCs of 0.96, 0.31, and 0.60 for VS, N, and P, respectively, based on the questionnaire, and sample analyses. Considering with the environmental impacts including land application from Hanwoo manure, P loss should be zero before and after composting. In this regard, nitrogen loss of 50 % occurs and VS was increased by 30 %. In addition, feasible cases for the calculations based on the notification from Ministry of Environment were compared with this study. Conclusions: The development of NLCs from Hanwoo manure in this study implies that the loss of nutrients in manure occurs during the composting or storing period. The mass balances of N and P from livestock manure to land application may be overestimated over the practical values. It is necessary to build up the database about each livestock category other than Hanwoo.

• 한국환경농학회지
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• 제40권4호
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• pp.359-365
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• 2021

BACKGROUND: Prohexadione-calcium (PC) is a plant growth regulator of cyclohexanedione family acting on inhibiting gibberellin biosynthesis and has been used to regulate shoot elongation of turfgrass in the golf course during the summer season. This study was conducted to investigate the effects of PC on the inhibition of shoot elongation, growth, and nitrogen uptake in Zoysia matrella. METHODS AND RESULTS: Treatments were as follows; non-treatment, control (TE 0.01 a.i. g/m²/100 mL), 0.0025PC (PC 0.0025 a.i. g/m²/100 mL), 0.005PC (PC 0.005 a.i. g/m²/100 mL), 0.01PC (PC 0.01 a.i. g/m²/100 mL) and 0.02PC (PC 0.02 a.i. g/m²/100 mL). Visual quality and chlorophyll content were not significantly different. As compared to non-treatment, shoot length and clipping yield in 0.005PC, 0.01PC and 0.02PC treatments were decreased by 29-36% and 65-82%, respectively, and those of 0.0025PC were not significantly different. N uptake of Z. matrella after applying PC was decreased by 28.9-77.8% than that of non-treatment. Inhibition effects of PC treatment in Z. matrella were not significantly different from those of control. CONCLUSION(S): These results indicated that the application of prohexadione calcium inhibited shoot elongation, clipping yield and N uptake amount in Z. matrella, and trinexapac-ethyl could be replaced with prohexadione-calcium in turfgrass management.

• 청정기술
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• 제9권2호
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• pp.49-55
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• 2003

우리나라엣 발생되는 축산 폐수는 $130,00m^3/day$로 전체 폐수의 0.43%에 불과하지만 총 BOD(생물학적 산소요구량)의 8.6%를 차지하고 있다. 그러나 생활폐수나 산업폐수와 달라 높은 질소, 인을 함유하고 있어 강이나 호수의 부영양화의 주원인이 되고 있다. 우리나라 축산폐수는 각 농가 당 폐수 발생량이 $2.5m^3/day$에 불과해 소규모이어서 경제적인 처리 방법이 필요하다. 부유물질 제거를 위해 미세여과 공정대신 충전탑을 이용한 전처리 방법을 통해 90% 이상의 부유물질을 제거하고 이어 역삼투압 방법을 적용하면 전질소와 전인의 제거율은 95%이상이나 되어 방류수는 전질소는 200 mg/이하, 전인 1 mg/L이하로 환경부의 축산폐수 배출수 수질 허용기준인 전질소 260 mg/L, 전인 50 mg/L이하를 충분히 만족 시킬 수 있다. $2m^3/day$의 축산폐수를 처리하는데 $0.4m^2$의 역삼투압 막 면적만 필요해 효과적인 소규모 처리시설이 가능함을 밝혔다. 처리에 소모되는 전력량도 월 30 Kwh로 에너지 절약적인 공정이 가능함을 예측하였다.

• KSBB Journal
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• 제24권2호
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• pp.195-200
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• 2009

본 연구에서는 Eschscholtzia californica의 이차 대사산물인 benzo[c]phenanthridine alkaloids의 생산량을 향상시키기 위해 주요 영양성분인 질소원 농도를 조절하여 배지의 조성을 최적화하였다. 그 결과, 질산과 암모늄 이온의 초기 농도 비율은 세포 성장과 alkaloids 생산량 증대에 중요한 영향을 미치는 인자로서 작용함을 볼 수 있었다. 총 질소 농도를 standard MS배지의 총 질소원 농도와 동일하게 유지하고 (60 mM), 농도 비율 다양하게 조절했을 때, 세포 성장과 alkaloids 생산량은 질산과 암모늄 이온을 각각 단독으로 이용할 때 보다 효율적으로 증대함을 볼 수 있었다. 최대 성장 (9.84 g DCW/L)과 alkaloids 생산량 (60.72 mg/L)은 50 : 10의 비율에서 나타났으며, 농도 비율의 감소는 세포 성장을 억제하고 alkaloids 생산량을 감소시켰다. 또한, 질산과 암모늄 이온이 세포 성장과 alkaloids 생산량에 미치는 영향력을 보다 명확히 확인하기 위해 질산 이온과 암모늄 이온 농도를 각각 조절한 결과, 암모늄 이온이 증가할수록 alkaloids 생산량은 비슷하나, 세포 성장은 감소하였으며, 또한, 질산 이온의 농도를 증가시킬수록 세포 성장은 비슷한 값을 나타내었지만, alkaloids 생산량은 다양한 차이를 나타내었다. 본 실험에서 세포성장과 alkaloids 생산량에 적합한 농도는 50 : 25 (mol/mol) 비율에서 나타났으며, 본 실험을 통해 Eschscholtzia californica의 현탁 세포배양에서 질소원 농도의 조절을 통한 외부 환경조절은 세포 성장과 alkaloids 향상에 매우 효과적이며, 소량의 암모늄 이온의 첨가 시 질산 이온 농도조절은 세포 성장을 억제하지 않으면서 alkaloids 생산량을 유도하는데 적합한 이온임을 확인하였다.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1986년도 추계학술대회
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• pp.506-508
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• 1986

Metabolic activity of inorganic nitrogenous compounds affects not only microbial growth but also metabolite production in fermentation technology. We have worked on the enzymes participating in ammonia assimulation of some fermentation bacteria. This paper summarizes the results on glutamine synthetase and its application in practical field. Glutamine synthetase (L-glutamate:ammonia ligase, EC. 6.3.1.2) catalyzes the formation of glutamine from glutamate and ammonia at the expense of cleavage of ATP and inorganic phosphate. The enzyme plays a dual role in nitrogen metabolism in bacteria; it is a key enzyme not only in the biosynthesis of various compounds through glutamine but also in the regulation of synthesis of some enzymes involved in the metabolism of nitrogenous compounds. The detailed works with the Eschericia coli and other enterobacterial enzymes revealed that glutamine synthetase is controlled by the following complex of mechanisms: (a) feedback inhibition by end products, (b) repression and derepression of enzyme synthesis, (c) modulation of enzyme activity in response to divalent cation and (d) covalent modification of enzyme protein by adenylylation and its cascade control. Comparative studies have also been made on the enzymes from other organisms.

• 한국자동차공학회논문집
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• 제16권1호
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• pp.127-133
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• 2008

Since the 1960's, exhaust gas recirculation(EGR) has been used effectively in spark ignition(SI) engines to control the exhaust emissions of the oxides of nitrogen(NOx). The most important requirements for the application of EGR systems to conventional SI engines are controllable flow rate and good dynamic response. In order to evaluate the characteristics of the electronic EGR valve, a test bench which is consisted of blower, heater, air flow meter and driving unit for electronic EGR valve was set up to simulate engine operating conditions. During the tests, the valve actuation parameters were controlled and the valve lifts and flow rates were measured to infer the characteristics of EGR valve. The results confirmed the capabilities of mathematical analysis and it seems that the correction for the valve lift and potentiometer output is necessary to achieve precise control of EGR rates.

• Journal of Microbiology and Biotechnology
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• 제16권11호
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• pp.1661-1677
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• 2006

Rhizobium and related genera are soil bacteria with great metabolic plasticity. These microorganisms survive in many different environments and are capable of eliciting the formation of nitrogen-fixing nodules on legumes. The successful establishment of symbiosis is precisely regulated and requires a series of signal exchanges between the two partners. Quorum sensing (QS) is a prevalent form of population density-dependent gene regulation. Recently, increasing evidence indicates that rhizobial quorum sensing provides a pervasive regulatory network, which plays a more generalized role in the physiological activity of free-living rhizobia, as well as during symbiosis. Several rhizobia utilize multiple, overlapping quorum sensing systems to regulate diverse properties, including conjugal transfer and copy number control of plasmids, exopolysaccharide biosynthesis, rhizosphere-related functions, and cell growth. Genomic and proteomic analyses have begun to reveal the wide range of functions under quorum-sensing control.