• 한국토양비료학회지
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• 제49권1호
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• pp.17-29
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• 2016

Though there is an abundant supply of nitrogen in the atmosphere, it cannot be used directly by the biological systems since it has to be combined with the element hydrogen before their incorporation. This process of nitrogen fixation ($N_2$-fixation) may be accomplished either chemically or biologically. Between the two elements, biological nitrogen fixation (BNF) is a microbiological process that converts atmospheric di-nitrogen ($N_2$) into plant-usable form. In this review, the genetics and mechanism of nitrogen fixation including genes responsible for it, their types and role in BNF are discussed in detail. Nitrogen fixation in the different agricultural systems using different methods is discussed to understand the actual rather than the potential $N_2$-fixation procedure. The mechanism by which the diazotrophic bacteria improve plant growth apart from nitrogen fixation such as inhibition of plant ethylene synthesis, improvement of nutrient uptake, stress tolerance enhancement, solubilization of inorganic phosphate and mineralization of organic phosphate is also discussed. Role of diazotrophic bacteria in the enhancement of nitrogen fixation is also dealt with suitable examples. This mini review attempts to address the importance of diazotrophic bacteria in nitrogen fixation and plant growth improvement.

• 한국토양비료학회지
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• 제32권2호
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• pp.109-114
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• 1999

벼 집약적(集約的) 재배증계하(栽培證系下)에서 화학비료 시용량 절감 및 퇴비의 이용가능성(利用可能性)을 검토키 위하여 영남농업시험장에서 30년간 실시한 동일비료(同一肥料) 장기연용(長期連用)시험을 중심으로 벼 수량성 및 질소이용효율의 연도별 변이를 분석한 결과는 다음과 같다. 동일비료(同一肥料)연용년도별 벼 수량성(收量性)변화는 퇴비단용구에서 통계적으로 유의한 증가를 보인 반면 무비구와 질소결제구에서는 감소의 경향을 보였고, 퇴비(堆肥)의 효과(效果)는 초기(初期) 10년간(年間)은 뚜렷한 차(差)가 없었으나 그 후(後) 점증(漸增)하여 30년(年)이 경과(經過)한 1996년(年)의 수량(收量)은 3요소구(要素區)의 80%수준(水準)이었다. 처리별(處理別) 요소흡수량(窒素吸收量)은 3요소+퇴비구가 $167kg\;ha^{-1}$로 높았으며 질소회수율(窒素回收率)($RE_N$)은 퇴비단용시(堆肥單用時) 0.74로 가장 높은 반면, 인산(燐酸) 및 칼리결제구(缺除區)가 0.30낮았다. 3요소(要素) 시용구(施用區)에서 질소(窒素)의 농업적(農業的) 효율(效率)($AE_N$)은 평균 12.8 kg/kg N인 반면, 질소비료생산성(窒素肥料生産性)($PFP_N$)은 37.7 kg/kg N으로 높았으며 AE_N과 PFP_N 공히 시험초대에는 감소하는 경향을 보였으나 후기 연대에는 $AE-N$의 경우 증감이 없는 반면, $PFP_N$은 증가하였다. $AE_N$와 $PFP_N$ 차(差)를 천연질소공급력(天然窒素供給力)(INS)으로 표시할 수 있으므로 그 차는 3요소(要素)+퇴비구(堆肥區)가 28.4로 3요소구(要素區)에 비해 높았으며 시험년수(試驗年數)가 진행됨에 따라 INS는 더욱 커졌다.

• 한국재료학회지
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• 제21권12호
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• pp.639-643
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• 2011

Zinc oxide as an optoelectronic device material was studied to utilize its wide band gap of 3.37 eV and high exciton biding energy of 60 meV. Using anti-site nitrogen to generate p-type zinc oxide has shown a deep acceptor level and low solubility. To increase the nitrogen solubility in zinc oxide, group 13 elements (aluminum, gallium, and indium) was co-added to nitrogen. The effect of aluminum on nitrogen solubility in a $3{\times}3{\times}2$ zinc oxide super cell containing 72 atoms was investigated using density functional theory with hybrid functionals of Heyd, Scuseria, and Ernzerhof (HSE). Aluminum and nitrogen were substituted for zinc and oxygen sites in the super cell, respectively. The band gap of the undoped super cell was calculated to be 3.36 eV from the density of states, and was in good agreement with the experimentally obtained value. Formation energies of a nitrogen molecule and nitric oxide in the zinc oxide super cell in zinc-rich conditions were lower than those in oxygen-rich conditions. When the number of nitrogen molecules near the aluminum increased from one to four in the super cell, their formation energies decreased to approach the valence band maximum to some degree. However, the acceptor level of nitrogen in zinc oxide with the co-incorporation of aluminum was still deep.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1988년도 학술대회지
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• pp.1-10
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• 1988

조사포닌을 복강내 투여하면 1) 핵내의 RNA polymerase의 활성도, 2) 핵내의 RNA합성, 3) 세포질의 RNA합성,4) 세포질내의 폴리리보좀 함량, 5) in vitro 상태에서의 쥐간의 polysome과 micro-some으로의 아미노산 유입율, 6) 방사능 표지된 아미노산의 혈청 단백질로의 유입율이 증가하였음을 과거에 보고 한 바 있으며 또한 4주간 조사포닌을 투여한 쥐에서 적출한 간세포를 전자 현미경으로 조사한 결과, 조면 소포체가 상당히 증가하였으며 초원심분리기로서 막에 결합한 ribosome에서의 polysome함량의 증가를 확인하였다. 최근 streptozotocin으로 유도한 단백질 결핍성 당뇨병 쥐에 $Rb_2$를 계속적으로 주사한 결과 blood urea nitrogen과 간내의 urea 농도가 현저히 감소하였으며 혈청내의 총단백질과 알부민의 농도가 대조군의 수치에 비하여 증가한 반면 간내의 RNA와 총 ribosome, 막에 결합된 ribosome의 함량이 증가하였다. 또한 $Rb_2$투여로 혈청내의 총단백질로의 방사능 표지 전구물질의 유입량이 증가하였으며 당뇨쥐에서의 질소균형을 개선시켰다. 이러한 실험적 결과에 근거하여 인삼 사포닌은 대사를 촉진시키고 RNA, 단백질 합성 등을 촉진하는 것으로 생각된다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1994년도 제2회 추계심포지움
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• pp.69-80
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• 1994

Although ureases play important roles in microbial nitrogen metabolism and in the pathogenesis of several human diseases, little is known of the mechanism of metallocenter biosynthesis in this Ni-Containing enzyme. Klebsiella aerogenes urease apo-protein was purified from cells grown in the absence of Ni. The purified apo-enzyme showed the same native molecular weight, charge, and subunit stoichiometry as the holo-enzyme. Chemical modification studies were consistent with histidinyl ligation of Ni. Apo-enzyme could not be activated by simple addition of Ni ions suggesting a requirement for a cellular factor. Deletion analysis showed that four accessory genes (ureD, ureE, ureF, and ureG) are necessary for the functional incorporation of the urease metallocenter. Whereas the $\Delta$ureD, $\Delta$ureF, and $\Delta$ureG mutants are inactive and their ureases lack Ni, the $\Delta$ureE mutants retain partial activity and their ureases possess corresponding lower levels of Ni. UreE and UreG peptides were identified by SDS-polyacrylamide gel comparisons of mutant and wild type cells and by N-terminal sequencing. UreD and UreF peptides, which are synthesized at ve교 low levels, were identified by using in vitro transcription/translation methods. Cotransformation of E. coli cells with the complementing plasmids confirmed that ureD and ureF gene products act in trans. UreE was purified and characterized. immunogold electron microscopic studies were used to localize UreE to the cytoplasm. Equilibrium dialysis studies of purified UreE with $^{63}$ NiC1$_2$ showed that it binds ～6 Ni in a specific manner with a $K_{d}$ of 9.6 $\pm$1.3 $\mu$M. Results from spectroscopic studies demonstrated that Ni ions are ligated by 5 histidinyl residues and a sixth N or O atom, consistent with participation of the polyhistidine tail at the carboxyl termini of the dimeric UreE in Ni binding. With these results and other known features of the urease-related gene products, a model for urease metallocenter biosynthesis is proposed in which UreE binds Ni and acts as a Ni donor to the urease apo-protein while UreG binds ATP and couples its Hydrolysis to the Ni incorporation process.ouples its Hydrolysis to the Ni incorporation process.s.

• Journal of Crop Science and Biotechnology
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• 제11권3호
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• pp.193-198
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• 2008

To develop a natural re-seeding technology, the optimum soil incorporation time of Chinese milk vetch(CMV) plant residues, seed persistence in soil, biomass production and subsequent rice yield were determined from 2005 to 2007 in rice with CMV green manure in southern Korea. Generally, insufficient seedling stand was regenerated with CMV incorporation to the soil at 20 and 25 days after flowering(DAF), while high regeneration of greater than 400 seedlings per $m^2$ was observed at 35 and 40 DAF. High re-seeding stand of CMV incorporated at 35 DAF or later was related with high seed viability and heavy seed weight. Appreciable number of CMV seeds remained 4 month after burial in soil and a good number of CMV seedlings regenerated from this seed bank at rice harvest time in the fall. Based on the relationships among re-seeding number of CMV plants, seed weight and seed viability, CMV plants should be incorporated into the soil 35 DAF(May 30) or later when CMV seeds were sufficiently matured. The natural re-seeding stand for the 3-year trials was stable ranging from 437 to 700 plants per $m^2$ and the biomass production was sufficient to supply nitrogen for rice growth. The use of re-seeding CMV plant can produce similar rice yield like that of rice without CMV green manure.

• 환경생물
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• 제27권3호
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• pp.279-284
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• 2009

In order to understand food sources-metabolism for the pacific oyster (Crassostrea gigas), the stable isotope ratios of carbon (${\delta}^{13}C$) and nitrogen (${\delta}^{15}N$) of its gut, gill, and muscle as well as potential food sources (particulate organic matter, sedimentary organic matter, benthic microalgae, seagrass detritus) were determined in Dongdae Bay. Average ${\delta}^{13}C$ and ${\delta}^{15}N$ values reflect that oysters primarily fed on sedimentary organic matter as opposed to suspended organic matter during summer and winter seasons. However, the relatively enriched $^{15}N$ values of particulate organic matter (>$250{\mu}m$) and sedimentary organic matter in the summer may be due to the photosynthetic incorporation of $^{15}N$-enriched nitrogen (DIN) or the spawning events of bivalves. Specific oyster tissues (gut, gill, and muscle) revealed different metabolic pathways, which were determined through analysis of ${\delta}^{13}C$ and ${\delta}^{15}N$ in each organ. The present results suggest the determination of carbon and nitrogen stable isotopes to be a useful approach in ecological research related to the food sources- metabolism of Crassostrea gigas.

• Corrosion Science and Technology
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• 제19권1호
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• pp.31-36
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• 2020

An efficient wet process approach to modifying natural graphite (NG) electrodes for Li-ion batteries is introduced in this paper. With homogeneous mixing and thermal decomposition of NG with diammonium phosphate ((NH₄)₂HPO₄), phosphorus and nitrogen were successfully incorporated into the surface layer of NG particles. Electron microscopy and X-ray photoelectron spectroscopy analyses demonstrated that the surface was well modified by this process. As a result, the treated NG electrodes exhibited much improved electrochemical performance over pristine NG at two different temperatures: 25 ℃ and 50 ℃. Excellent capacity retention of 95.6% was obtained after 100 cycles at 50 ℃. These enhanced properties were confirmed in a morphology analysis on the cross-sections of the NG electrodes after galvanostatic cycling. The improved cycle and thermal stabilities can be attributed to the surface treatment with phosphorus and nitrogen; the treatment formed a stable solid electrolyte interphase layer that performed well when undergoing Li insertion and extraction cycling.

• 한국환경농학회지
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• 제37권1호
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• pp.28-33
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• 2018

수박 휴작기에 풋거름 작물로 헤어리베치와 호밀을 재배한 후 토양으로의 환원이 후작물 수박의 생육과 수량 그리고 토양의 질산태질소 함량에 미치는 영향을 구명하고자 하였다. 파종 후 151일간 재배한 후에 헤어리베치와 호밀의 토양 질소 환원량은 각각 79 kg/ha와 88 kg/ha였다. 헤어리베치와 호밀은 시설하우스 한 동씩 두 동의 면적에 풋거름 작물구, 풋거름작물에 요소 25%, 50%, 75% 처리구, 요소 100% 등 5처리를 각각 두었다. 수박의 생육은 각각의 헤어리베치 및 호밀 처리에서 동일한 생육을 나타냈고 수박의 수량에서도 처리간의 통계적인 유의성은 없었다. 토양의 질산태 질소함량은 수박 정식 후 재배일수가 증가할수록 지속적으로 감소하여 정식 후 75일째에 가장 낮은 함량을 나타내었는데 호밀처리구는 호밀만 투입만 처리가 52 mg/kg으로 가장 낮았고, 헤어리베치 처리간 비교에서도 마찬가지로 헤어리베치만 공급한 처리가 가장 낮은 44 mg/kg이었다. 헤어리베치와 호밀 등 녹비작물만의 투입으로도 수박의 재배기간 동안에 토양의 질산태 질소가 40 mg/kg 이상으로 존재하여 화학비료의 추가적인 시비 없이도 동일한 생육을 보인 것으로 판단되었다. 하지만 수박의 수량과 재배기간에의 토양 중 질산태질소와의 관계에 대한 추가적인 연구가 필요할 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제29권11호
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• pp.1616-1624
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• 2016

The aim of present experiment was to investigate the effect of protein reduction in commercial broiler chicken rations with incorporation of de-oiled rice bran (DORB) and supplementation of limiting amino acids (valine, isoleucine, and/or tryptophan) with ration formulation either on total amino acid (TAA) or standardized ileal digestible amino acids (SIDAA). The experimental design consisted of $T_1$, TAA control; $T_2$ and $T_3$, 0.75% and 1.5% protein reduction by 3% and 6% DORB incorporation, respectively by replacing soybean meal with supplemental limiting amino acids to meet TAA requirement; $T_4$, SIDAA control, $T_5$ and $T_6$, 0.75% and 1.5% protein reduction by DORB incorporation (3% and 6%) with supplemental limiting amino acids on SIDAA basis. A total of 360 dold fast growing broiler chicks (Vencobb-400) were divided into 36 homogenous groups of ten chicks each, and six dietary treatments described were allocated randomly with six replications. During 42 days trial, the feed intake was significantly (p<0.05) reduced by TAA factor compared to SIDAA factor and protein factor significantly (p<0.05) reduced the feed intake at 1.5% reduction compared to normal protein group. This was observed only during pre-starter phase but not thereafter. The cumulative body weight gain (BWG) was significantly (p<0.05) reduced in TAA formulations with protein step-down of 1.5% ($T_3$, 1,993 g) compared to control ($T_1$, 2,067 g), while under SIDAA formulations, BWG was not affected with protein reduction of 1.5% ($T_6$, 2,076 g) compared to $T_4$ (2,129 g). The feed conversion ratio (FCR) was significantly (p<0.05) reduced in both TAA and SIDAA formulations with 1.5% protein step-down ($T_3$, 1.741; $T_6$, 1.704) compared to respective controls ($T_1$, 1.696; $T_4$, 1.663). The SIDAA formulation revealed significantly (p<0.05) higher BWG (2,095 g) and better FCR (1.684) compared to TAA formulation (2,028 g; 1.721). Intake of crude protein and all limiting amino acids (SID basis) was higher in SIDAA group than TAA group with resultant higher nitrogen retention (4.438 vs 4.027 g/bird/d). The nitrogen excretion was minimized with 1.5% protein reduction (1.608 g/bird) compared to normal protein group (1.794 g/bird). The serum uric acid concentration was significantly reduced in $T_3$ (9.45 mg/dL) as compared to $T_4$ (10.75 mg/dL). All carcass parameters were significantly (p<0.05) higher in SIDAA formulation over TAA formulation and 1.5% protein reduction significantly reduced carcass, breast and thigh yields. In conclusion, the dietary protein can be reduced by 0.75% with TAA formulation and 1.5% with SIDAA formulation through DORB incorporation and supplementation of limiting amino acids and among formulations, SIDAA formulation was better than TAA formulation.