• Title/Summary/Keyword: $N_2$ fixation

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Structures and functions of microbial extracellular or wall polysaccharides in the physiology of producer organisms (미생물 다당류의 구조와 세포생리학적 기능)

  • 박용일
    • The Microorganisms and Industry
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    • v.26 no.1
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    • pp.18-30
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    • 2000
  • Three kinds of organic matter such as glucose, oxalic acid, and ethanol were added to the media(N-free or NO$\_$3/-riched) and their effects on the nitrogen fixation of Nostoc pruniforme were measured by manometric technique through the experiments in vivo. 1) The organic matters used in this experiments showed effective results as a role of substrate for the fixation of atmospheric nitrogen. 2) In the nitrogen-free medium treated with the both of flucose nad ethanol, the highest nitrogen uptakes were detected in the treated of low concentrations (glucose ; 0.1%, 0.5%, ethanol : 0.1%, 0.5%). On the contrary, the highest nitrogen uptakes in NO$\_$3/-riched medium were measured at the treated of high concentrations (glucose ; 2%, 1%, ethanol ; 1.5%, 1.0%). 3) The highest nitrogen uptakes in N-free medium treated with oxalic acid were measured at the concentration of 2% and 1%, respectively. In the medium of NO$\_$3/-riched, the nitrogen uptakes were in the opposite directions.

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Physiological Responses and Growth Performance of Alnus firma and Alnus hirsuta Seedlings to Artificial Soil Acidification (인위적인 토양산성화에 대한 사방오리나무와 물오리나무 묘목의 생리반응 및 생장특성)

  • Choi, Dongsu;Toda, Hiroto
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.15 no.5
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    • pp.145-153
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    • 2012
  • To obtain basic information for evaluating resistance of soil acidification for growth, net photosynthesis, $N_2$ fixation rate and nutrient status of Alnus firma and Alnus hirsuta seedlings grown in brown forest soil acidified with $H_2SO_4$ or $HNO_3$ solution were investigated (control (pH=5.9), LN (pH=5.0; Low levels of Nitric acid), HN (pH=4.0; High levels of Nitric acid), LS (pH=5.0; Low levels of Sulfuric acid), and HS (pH=4.0; High levels of Sulfuric acid)). The shoot dry weight of Alnus firma and Alnus hirsuta and the root dry weight of Alnus hirsuta seedlings grown in the HN, LS and HS were significantly less than that of the seedlings grown in the control. The Chlorophyll a/b ratio in leaves of Alnus firma at LN, LS and HS was significantly lower than that of control. The concentration of N in leaves of Alnus hirsuta at HS was significantly higher than that of control. The net photosynthetic rate of Alnus firma and Alnus hirsuta seedlings at LN and HN was higher than that of control. Based on the results, we concluded that the negative effects of soil acidification due to sulfate deposition are greater than those of soil acidification due to nitrate deposition on growth, net photosynthesis and $N_2$ fixation rate of Alnus firma more than Alnus hirsuta.

Effect of N Application Rate on Fixation and Transfer from Vetch to Barley in Mixed Stands. (질소시용수준이 베치-보리 혼파 사초의 질소고정 및 베치에서 보리로 질소이동에 미치는 영향)

  • Lee Hyo Won;Kim Won Ho;Park Hyung Soo;Ko Han Jong;Kim Su Gon
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.25 no.1
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    • pp.1-6
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    • 2005
  • With recent interest organic farming the use of legumes including vetch and clover to provide N to adjacent crops is increasing in Korea. In the present studies, we conducted a trial to investigate the effects of the application of N rate on nitrogen fixation and transfer from vetch to barley in mixed stands. The experiment was arranged in a randomized complete block design with three replications. Four different N rates(0, 75, 113 and 150/ha) was used and vetch+barley was broadcasted manually on 1.5 $\times$2 m plot in Oct. 2001. Half of urea and K$_{2}O, 200 Phosphate and 75 kg potash per ha were applied as basal dressing md half of N md 75 potash were used for topdressing to soil surface on MarctL 2002. The equivalent of 1kg ha$^{-1}$ at($^{15}$NH$_{4}$)$_{2}$SO$_{4}$ solution at 99.8 atom $\%$$^{15}$N excess was applied to the microplot in mid April. Forage was harvested from each plot at ground level and separated into barley and vetch. Total N content and It values of samples were determined using a continuous flow stable isotope ratio mass spectrometry(IsoPrime-EA. Micromass, UK.). The percentage of legume H fixed from atmospheric N2 were 95.0, 93.8, 94.4 and $84.8\%$ with increment of N levels. The percentage of N transfer from vetch to barley by N-difference method with increment of N fertilizer were from 58 to$49\%$ while 39 to $23\%$ in $^{15}$N-dilution method. The amount of transfer from vetch to barley were 87 to 68 kg/ ha with N level by N-difference moth여 and 58 to -56/ha with N application levels by $^{15}$N dilution method. The amount of nitrogen fixation per ha were from 150 kg / ha to 219 kg / ha by different method, but on the other side 49 to 105kg/ha by N$^{15}$-dilution.

A Study on Eye-Tracking by Speed & Direction Changes of Graphic Images (그래픽 이미지의 움직임 속도와 방향 변화에 따른 시선 이동 추적 연구)

  • Kim, Sehwa;Seong, Cheekyong
    • Journal of Communication Design
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    • v.38
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    • pp.80-90
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    • 2012
  • The purpose of this study is to determine the differences in eye-tracking, which is one of the emotional reactions of the autonomic nervous system, against various experimental stimuli that vary in terms of the movement attributes of graphic image. This experiment conducted an analysis of variance of the movement factors(n) in each movement attribute(speed, horizontality movement, verticality movement, diagonal movement). Dependent variables were the fixation starting time, the fixation dwell time, the whole fixation time from stimulus appearance, and the eye-tracking length. The result of eye-tracking against movement speed showed nonsignificant differences for each movement attribute. In the horizontality movement, the → movement was higher than the ← movement. In the verticality movement, the ↑ movement was higher than the ↓ movement. In the diagonal movement, there was not significant differences for each movement attributes.

Biological Fixation of Carbon Dioxide by Synechocystis PCC 6803 (Synechocystis PCC 6803에 의한 이산화탄소의 생물학적 고정화)

  • 김장규;원성호;김남기
    • KSBB Journal
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    • v.13 no.1
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    • pp.101-107
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    • 1998
  • Carbon dioxide is estimated to be responsible for 60% of the global warming effect, and this percentage is tending upward. Studies on removal and fixation of $CO_2$ in the flue gas are recognized as one of the important roles of the future biotechnology. Photobiological systems have considerably higher photosynthetic efficiency than conventional biomass system. The experiment for the photosynthetic fixation of $CO_2$ and the biomass production was performed with various initial cell concentration in a tubular photobioreactor and a bubble column $CO_2$ contactor with a gas sparger of $CO_2$ -enriched air(0.03~20%). Synechocystis PCC 6803 could grow at 10~20% $CO_2$ content under pH control. The highest specific growth rate, 0.0258 $h^{-1}$ , was obtained at 5% $CO_2$-air mixture. The maximum cell production rate, 0.2784 g/L.day, was obtained when the initial cell concentration was 0.45 g/L at 5% $CO_2$ -air mixture. The maximum cell concentration was 2.03 g/L in the tubular photobioreactor when the light intensity was $45.5{\mu}$ $E/m^2$ . s. This system showed 0.482 g $CO_2$ /L . day of the $CO_2$ fixation.

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Practicability Strength Assessment of a Bone Metallic Plate at the Femur Fixation (대퇴골(Femur)고정용 골 금속판 제작 및 강도 평가)

  • Kim, Jeong-Lae;Ahn, Chang-Sik;Seo, Byoung-Do
    • Journal of the Ergonomics Society of Korea
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    • v.27 no.2
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    • pp.83-89
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    • 2008
  • Study was developed the metallic plate for fixation in the femur fracture and plates has a firm place in fracture treatment. This plates can be stabilized for fracture fixation as well as biological and dynamical device. The device's designation and sizing has a optimization with bending structural stiffness and strength, known meaning that is reliable regardless of the plate by the short type and long type. The bending strength of the curved metallic long plate has to evaluate a 11,000N and the bending strength of the curved metallic short plate has to evaluate a 6,525N. This see the X-ray image of bending angle made certain of 15$^{\circ}$ at number 2 and same 82.87$^{\circ}$ at number 2, 4, 5, 7, 8, 9, 10 by outside angle, and confirmed 25.26$^{\circ}$ at number 3, 3.68$^{\circ}$ at number 6, 15.64$^{\circ}$ at number 9 by inside angle. This study shows that keep up the metallic plate for fixation in the femur fracture through X-ray Image and the device can be used to support Revision case of Hip Implant and to use a case of Hip screw compression of Hip Neck Fracture. Short plate have a wrapping of femur and long plate have to preserve a pole of femur.

Treatment for Distal Humeral Fractures by Modified Anatomical Y-Plate (변형된 Y형 해부학적 금속판을 이용한 상완골 원위부 골절의 치료)

  • Moon Eun Sun;Park Jae Hyung;Lee Young Keun
    • Clinics in Shoulder and Elbow
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    • v.1 no.1
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    • pp.51-57
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    • 1998
  • Comminuted fracture of the distal end of the humerus in adults is very rare and difficult to treat. In operative treatment, an implant which can achieve accurate anatoraical reduction and rigid fixation is needed. But the pre­existing Y -shaped plate had wide and thick limbs and some problems in fixation for most distal humeral fractures. So we devised a modified plate which is more narrow and th1n and has a different hole distance and wing length (long lateral wing). The aim of the study was to evaluate the clinical result of this modified anatomical Y -plate. From 1991 to 1997, we treated 23 cases of distal humeral fractures using modified anatomical plate and the results were as follows. 1. Fracture type in 18 patients(78%) was C-type(C1,C2,C3) which were intraarticular and mostly displaced or comminuted. 2. Bony union was obtained in 22 patients(96%) through rigid fixation and observed radiologically at 3.5 months(2-6months) on the average. 3. In 23 patients, 19 patients(82%) showed satisfactory results after 34 months(6-73months) follow-up. So if the modified anatomical Y-plate is used in the treatment of distal humeral fracture, a satisfactory result can be obtained through a more accurate, easy, and rigid fixation than preexisting plate.

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Effect of Barley, Italian ryegrass and Legume Mixture on Nitrogen Fixation and Transfer to Grasses on Spring Paddy Field using Isotope Dilution and Difference Method (답리작 춘계포장에서 보리 및 이탈리안 라이그라스와 두과의 혼파비율이 동위원소 희석법 및 차이법을 이용한 질소고정 및 이동에 미치는 영향)

  • Lee, Hyo-Won;Lee, Hyo-Jin;Kim, Won Ho;Yoon, Bong Ki;Ko, Han Jong
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.36 no.4
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    • pp.318-324
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    • 2016
  • In order to study the effect of barley, Italian ryegrass (IRG), and legume mixture on nitrogen fixation and transfer to grasses on spring paddy field, an experiment was carried out from Oct. 2006 to June 2007 in Naju, Korea. A split plot design with three replications was used for the experiment. One reference plot was assigned for each treatment to determine nitrogen fixation. Main plots consisted of Chinese milk vetch, crimson clover, forage pea, and hairy vetch with barley, respectively. Subplot treatment were barley or IRG with four seeding ratio of legumes (50:50, 60:40, 70:30, and 80:20). To estimate N fixation by legumes, $^{15}N$ isotope dilution technique was used. $^{15}N$ fertilizer [$(^{15}NH_4)_2SO_4$ solution at 99.8 atom N] was uniformly applied to $600cm^2$ in the middle of each plot on April 15, 2007. Plots were harvest by hand on June 8, 2007. Dried sample were ground to a fine power and analyzed for total N isotope N. $^{15}N$ was determined using elemental analyzer-isotope ratio mass spectrometry. The calculation of N transfer was determined with the isotope dilution method. The content of N was higher in legumes than that in barley or Italian ryegrass. Nitrogen level in forage pea was significantly higher than that of other legumes. There were significantly differences in N content between legumes in IRG mixture. Atom % $^{15}N$ excess was significantly different in legumes with barley. The 60:40 sub plot had higher (p<0.05) atom % $^{15}N$ than other seeding ratio treatments. The enrichment ranged from 0 to 0.58. Compared to barley, the enrichment of IRG with its accompanied legumes was higher, ranging from 0.38 to 1.0. The N derived from the atmosphere (Ndfa) ranged from 0% to 49.5% with barley-legume mixture. It ranged from 0 to 60.5% in IRG-legume plots. N transfer from legumes to neighboring grasses was 12.3 to 90.9 kg/ha for barley-legume mixture and 31.7 to 107.8 kg/ha for IRG plots. IRG plots showed higher N transfer for IRG-legume mixture in general based on difference method. Based on $^{15}N$ dilution method, the N transfer was 0 to 36.1 kg/ha for barley-legume mixture and 0 to 50.6 kg/ha for IRG plots. There was a tendency toward higher N transfer on the difference method than that of the $^{15}N$ dilution method.

Induction of Symbiosis between Nostoc muscorum and Cultured Plant Cells II. Changes of nitrogen fixation ability and morphology by association of N. muscorum with cultured tobacco cells (Nostoc muscorum과 식물배양세포의 공생유도에 관한 연구 II. N. muscorum과 담배배양세포의 혼합배양에 따른 질소고정능과 형태적 변화)

  • 정현숙
    • Journal of Plant Biology
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    • v.30 no.4
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    • pp.257-266
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    • 1987
  • Investigation on the ability of nitrogen usage by N2-fixing Nostoc muscorum and cultured tobacco cells when they were associately cultured on nitrogen-free media was carried out. Also, effect of polyamines on the associated cultured condition was carried out. In addition, morphological changes of N. muscorum and cultured tobacco cells in associate culture were observed to detect the possibility of induction of nitrogen fixing ability on cultued plant cells. The activity of nitrogenase increased markedly when N. muscorum was grown exclusively on nitrogen-free media. When N. muscorum was cultured associately with cultured tobacco cells on nitrogen-free media containing polyamines, high activity was detected in 10-4 M spermine treated group. Investigation on the change of polyamine amounts showed two times increase in spermidine and eight times increase in spermine on a associate culture. These effects of associated culture were shown through morphological change such as dense loclization of N. muscorum around the cultured tobacco cells as well as inside the cells. These results indicate the viability of N. muscorum in cultured tobacco cells and possible induction of nitrogen fixation ability by symbiosis.

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