• Title/Summary/Keyword: Biological fixation

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Propylene Carbonate Synthesis using Supercritical $CO_2$ and Ionic Liquid (초임계 이산화탄소와 이온성 액체를 이용한 Propylene Carbonate 합성)

  • Kim, Byeong-Heon;Jang, Sung-Hyeon;Min, Se-Ryeon;Kim, Hwa-Yong
    • Clean Technology
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    • v.17 no.1
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    • pp.37-40
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    • 2011
  • Some ionic liquids are suitable for catalysts and solvents which are applicable to $CO_2$ fixation reaction converting $CO_2$ to carbonate. Using the ionic liquids, the synthesis process will become greener and simpler because of easy catalyst recycling and unnecessary use of volatile and harmful organic solvents. In this work, the synthesis of propylene carbonate from propylene oxide using carbon dioxide and ionic liquids were measured at high pressures up to ~140 bar and at temperatures between $60^{\circ}C$ and $80^{\circ}C$. As a results, we found the optimum condition and obtained the maximum yield under that condition.

Differential Responses of Two Freshwater Cyanobacteria, Anabaena variabillis and Nostoc commune, to Sulfonylurea Herbicide Bensulfuron-methyl

  • KIM JEONG-DONG;LEE CHOUL-GYUN
    • Journal of Microbiology and Biotechnology
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    • v.16 no.1
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    • pp.52-56
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    • 2006
  • The effect of bensulfuron-methyl on the nontargeted cyanobacteria was greater on A. variabillis than N. commune. Both A. variabillis and N. commune were initially able to utilize low concentrations of the herbicide, bensulfuron-methyl, whereas higher concentrations of bensulfuron-methyl or the hydrolyzed products of the herbicide were found to be toxic. Growth and photosynthesis inhibitions of over $50\%$ were observed, when 8 to 10 ppm of the herbicide was applied. Nitrogenase activities of the cyanobacteria were decreased by $94-98\%$ in A. variabillis and by $85-86\%$ in N. commune after 24 h of incubation with 10 ppm and 20 ppm of bensulfuron-methyl. Nitrogenase activities were also inhibited by the addition of ammonium salts as low as 0.05 mM. Furthermore, the toxic effect of the herbicide was the highest at pH 4-6, showing approximately $42-60\%$ toxicity, whereas much lower toxicity $(9-28\%)$ was observed at higher pH of 7-10, due to base-catalyzed hydrolysis of bensulfuron-methyl.

Why do Chickpea (Cicer arietinum L. cv. Tyson) Bacteroids Contain Little Poly-β-Hydroxybutyrate?

  • Lee, Hoi-Seon
    • Journal of Applied Biological Chemistry
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    • v.42 no.1
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    • pp.1-6
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    • 1999
  • Poly-${\beta}$-hydroxybutyrate (PHB) and enzymes related PHB metabolism have been measured in nitrogen-fixing symbiosis of chickpea and cowpea plants. Bacteroids from chickpea and cowpea contained PHB to 0.8% and 43% of their dry weight, respectively, whereas the free-living cells CC 1192 and I 16 produced $285{\pm}55mg$ and $157{\pm}18mg$ of PHB g (dry weight)$^{-1}$. To further understand why chickpea bacteroids contained little PHB, the enzyme activities of PHB metabolism (3-ketothiolase, acetoacetyl-CoA reductase, PHB depolymerase, and 3-hydroxybutyrate dehydrogenase), the TCA cycle (malate dehydrogenase, citrate synthase, and isocitrate dehydrogenase), and related reactions (malic enzyme, pyruvate dehydrogenase, and glutamate:2-oxoglutarate transaminase) were compared in extracts from chickpea and cowpea bacteroids and the respective free-living bacteria. Significant differences were observed between chickpea and cowpea bacteroids and between the bacteroid and free-living forms of CC 1192, with respect to the capacity for some of these reactions. It is indicated that a greater potential for oxidizing malate to oxaloacetate in chickpea bacteroids could be a factor that favors the utilization of acetyl-CoA in TCA cycle rather than for PHB synthesis.

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Optimising the Extraction of Bacteria, Heterotrophic Protists and Diatoms, and Estimating Their Abundance and Biomass from Intertidal Sandy Sediments

  • Lee, Won-Je;Patterson, David J.
    • Journal of the korean society of oceanography
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    • v.37 no.2
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    • pp.58-65
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    • 2002
  • The study of microbial communities in sediments is impaired by the lack of reliable extraction methods. This study reports on the efficiency of recovery of a method for extracting bacteria, protists and diatoms from sandy sediments using a modified decant/fix method. The best extractions were achieved after fixation with a microtubule stabilising fixative and subsequent sonication for 80 seconds. We estimate that the efficiencies of recovery of bacteria and mixed heterotrophic flagellates were $96.4{\pm}3.5\%$ and $96.9{\pm}4.6\%$, respectively. Diatoms were recovered with an efficiency of 38-83% and varied considerably from species to species. This study suggests that the decant/fix method is effective in extracting small cells such as bacteria and heterotrophic flagellates, and that the efficiency of recovery of the method varies due to cell length and different types of organisms. When microbial carbon biomass had been underestimated by up to 32%, with much of that relating to larger cells such as microalgae and ciliates. We note that the corrected abundances may be still a subset of the total numbers present.

Radiation induced Chromosome aberration in human Iymphocyte detected by Fluorescence in sifu hybridization (FISH(Fluorescence in situ hybridization)를 이용하여 분석한 방사선에 의해 유발된 림프구의 염색체 이상)

  • 정해원;손은희;기혜성;하성환
    • Environmental Mutagens and Carcinogens
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    • v.16 no.2
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    • pp.88-96
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    • 1996
  • Fluorescence in situ hybridization (FISH) with the DNA probe for human chromosome 4 was used to analyse in vitro radiation induced chromosome rearrangement in peripheral lymphocyte. Translocations, dicentrics, acentrics and color junctions involving the painted chromosome were scored according to the Protocol for Aberration Identification and Nomenclature Terminology (PAINT) system. The frequency of chromosome rearrangements including reciprocal translocation, dicentric, acentric fragment and color junction increased with radiation dose. The frequency of dicentric chromosome reduced by the fixation time following irradiation, whereas that of translocation was relatively persistent. The applicability of FISH for scoring stable translocation for biological dosimetry was demonstrated.

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Simplified FE Analysis for the Design of Pedicle Screw System (척추경 나사못 시스템의 설계를 위한 단순 유한요소해석)

  • 정일섭;안면환
    • Journal of Biomedical Engineering Research
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    • v.21 no.6
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    • pp.559-566
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    • 2000
  • Methodology for finite element analysis of vertebral column and pedicle screw system, which circumvents the tremendous difficulties in geometric, material, and structural modeling, is proposed. The simplification is focused on the modeling of the cancellous bone in vertebral body the intervertebral disc. and the instrumented internal fixation devices. Each proposed modeling technique is justified to result in reasonable accuracy. These methods are believed to be suitable for the development of pedicle screw systems, not only because modeling itself is much simpler. but also because reliable empirical data for disc stiffness may be incorporated with little additional effort, and presumably frequent design change may be easily reflected on the analysis.

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Analysis of Criteria Regarding Frontal and Side Impacts of Wheelchair Occupant in Vehicle by Computer Simulation Method (컴퓨터 시뮬레이션 방법을 이용한 휠체어 탑재 차량의 전방/측방충돌 시 휠체어 탑승자의 위험도 분석)

  • Kim, S.M.;Lee, M.P.;Park, S.Y.
    • Journal of Biomedical Engineering Research
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    • v.27 no.6
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    • pp.365-369
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    • 2006
  • According to the IIHS (Insurance Institute fur Highway Safety), side impacts are made up 30% of all accidents (reported 1998). In the case of auto accidents, head and neck injuries were most common as 58%, injuries to the body's trunk equaled 32%, and injuries to the abdomen were 21%. Therefore in this study, injury of wheelchair occupant in frontal and side impact of wheelchair loaded vehicle was analyzed using computer simulation method. The occupant was restrained at the rear of wheelchair by the lap belt. The detailed fixation and restrain conditions of the wheelchair occupant are referred to SAR J2249's recommendation. We estimated HIC(Head Injury Criteria) and HNIC (Head and Neck Injury Criteria) based on measured data.

The Response of QTL in Generation during Selection (선발과정에서의 세대별 QTL 좌위 고정에 관한 연구)

  • Lee Ji-Woong
    • Journal of Embryo Transfer
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    • v.20 no.3
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    • pp.217-232
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    • 2005
  • The objective of this study was to determine the response of QTL in each generation during selection to develop inbred lines. The simulation program was written in Fortran. Magnitude of QTL effects, base population size, number of QTL assigned to population, and the allelic frequency for the positive allele at each major QTL were highly associated with number of generations to fixation of QTLs during selection. Populations with larger QTL effects and larger base population size had more individuals with fixed QTL. However, a smaller number of QTL assigned to population had a higher fraction of individuals with fixed QTL at each generation compared with more populations with QTL. This simulation study will help to design biological experiments for detection of QTL-marker association using inbred population and to determine optimum number of lines with fixed QTL during inbred line development. To complement this study, additional simulation should be need with abundant replicates, more various population sizes, magnitude of QTL effects, and recombination between markers and QTLs.

Development of Spine Motion Analyzer (척추운동 분석기의 개발)

  • Kim, Y.E.;Roh, B.H.;Ryu, J.H.;Ahn, J.H.;Lee, C.K.;Choi, K.W.
    • Proceedings of the KOSOMBE Conference
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    • v.1996 no.05
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    • pp.266-270
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    • 1996
  • External linkage type spine motion analyzer was developed for measuring relative trunk motion respect to the pelvis. A special program for calculation of the relative angular motion and graphical display were also developed. The developed device assured its accuracy and conveniency after application to 15 normal volunteers and 18 patients after fixation and decompression surgery. Compare to the normal subjects, patients shows different angular motion especially in the angular acceleration.

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Biological applications of the NanoSuit for electron imaging and X-microanalysis of insulating specimens

  • Ki Woo Kim
    • Applied Microscopy
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    • v.52
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    • pp.4.1-4.11
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    • 2022
  • Field emission scanning electron microscopy (FESEM) is an essential tool for observing surface details of specimens in a high vacuum. A series of specimen procedures precludes the observations of living organisms, resulting in artifacts. To overcome these problems, Takahiko Hariyama and his colleagues proposed the concept of the "nanosuit" later referred to as "NanoSuit", describing a thin polymer layer placed on organisms to protect them in a high vacuum in 2013. The NanoSuit is formed rapidly by (i) electron beam irradiation, (ii) plasma irradiation, (iii) Tween 20 solution immersion, and (iv) surface shield enhancer (SSE) solution immersion. Without chemical fixation and metal coating, the NanoSuit-formed specimens allowed structural preservation and accurate element detection of insulating, wet specimens at high spatial resolution. NanoSuit-formed larvae were able to resume normal growth following FESEM observation. The method has been employed to observe unfixed and uncoated bacteria, multicellular organisms, and paraffin sections. These results suggest that the NanoSuit can be applied to prolong life in vacuo and overcome the limit of dead imaging of electron microscopy.