• Title/Summary/Keyword: bio-ion

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Effects of Relative Humidity Levels on Ion Leakage, Photosynthesis, Stomatal Resistance, Water Use Efficiency and Growth in Cos Lettuce 'Manavert' (습도 조건이 Cos Lettuce의 전해질, 광합성, 기공저항, 수분이용 효율 및 생육에 미치는 영향)

  • 최기영;김남영;박미희;이용범
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 1998.10a
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    • pp.111-114
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    • 1998
  • 상추의 Ca 결핍으로 인한 생리 장해인 tipburn은 \circled1 배지 중의 Ca이 부족했을 때 \circled2 배지 중 Ca 은 충분하나 여러 원인에 의해서 Ca 흡수가 억제될 때, 또는 \circled3흡수 및 지상부로의 이동은 어느 정도 이루어지나 필요한 부위로의 충분한 공급이 이루어지지 않을 때 또는 필요량이 많아 공급이 부족할 때 등이다. 본 실험은 지상부로의 Ca 이동에 영향을 미치는 인자 중 습도 조건을 달리 했을 때의 막투과성의 변화와 기공반응 및 생육에 미치는 영향을 살펴봄으로써 상추의 Ttpburn 발생에 미치는 습도의 영향을 알아보고자 실시하였다. (중략)

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Development of micro-mold for New Injecton Molder to fabricate Micro-Nano system (Micro-Nano 시스템 제조를 위한 소형 차세대 사출기 개발과 이를 위한 Micro meld의 개발)

  • 황교일;류경주;김훈모
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.910-913
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    • 2002
  • Recently, the sensor and actuator are developed with EAP(Electro Active Polymer). Common used of they is close at hand, the bio chip and Lab on a chip are researched. For developed bio and micro system, a researcher applies semiconductor fabrication or make it by his hand. But, this method takes long time and a tolerance is large So they are problem of common used. So In this paper we propose the new inject ion molder and micro mold. The micro mold is different from exist ing mold. In this paper, the fabration of micro mold is introduced to inject.

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Bio-Rex 젤을 이용한 난백으로 부터의 Lysozyme의 분리

  • Kim, Hyeong-Won;Park, In-Gyu;Song, Jae-Yang;Kim, In-Ho
    • 한국생물공학회:학술대회논문집
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    • 2002.04a
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    • pp.493-496
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    • 2002
  • Lysozyme is an enzyme which has the ability to lyse bacteria such as Micrococcus lysodeikticus or gram positive and gram negative bacteria by hydrolyzing in the peptidoglycan layer of the bacterial cell wall. Lysozyme is abundantly contained in an egg white. In order to obtain lysozyme from egg white, we used Bio-rex ion exchange chromatography and can identify the exist of lysozyme by SDS-PAGE and protein assay.

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In Situ X-ray Absorption Spectroscopic Study for α-MoO3 Electrode upon Discharge/Charge Reaction in Lithium Secondary Batteries

  • Kang, Joo-Hee;Paek, Seung-Min;Choy, Jin-Ho
    • Bulletin of the Korean Chemical Society
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    • v.31 no.12
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    • pp.3675-3678
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    • 2010
  • In-situ X-ray absorption spectroscopy (XAS) was used to elucidate the structural variation of $\alpha-MoO_3$ electrode upon discharge/charge reaction in a lithium ion battery. According to the XAS analysis, hexavalent Mo atoms in $\alpha-MoO_3$ framework are reduced as the amount of intercalated lithium ions increases. As lithium de-intercalation proceeds, most of pre-edge peaks are restored again. However, according to the Fourier transforms of the extended X-ray absorption fine structure (EXAFS) spectra, lithium de-intercalation reaction is partially irreversible upon the charge reaction, which is one of the main reasons why the capacity of $\alpha-MoO_3$ electrode decreases upon successive discharge/charge cycles.

Synthesis and color-controllable luminescence in Dy3+-activated CaWO4 phosphors

  • Du, Peng;Yu, Jae Su
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.170.2-170.2
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    • 2015
  • Enormous interest in trivalent rare-earth (RE) ions activated luminescent materials has been gaining owing to their promising applications in bio-imaging, solar cells, white light-emitting diodes and field-emission displays. Among these trivalent RE ions, dysprosium (Dy3+) was widely investigated due to its unique photoluminescence (PL) emissions. A series of Dy3+-activated CaWO4 phosphors were prepared by a facile high-temperature solid-state reaction method. The X-ray diffraction, PL spectra, cathodoluminescence (CL) spectra as well as PL decay curves were used to characterize the prepared samples. Under ultraviolet light excitation, the characteristic emissions of Dy3+ ions were observed in all the obtained phosphors. Furthermore, the PL emission intensity increased gradually with the increment of Dy3+ ion concentration, reaching its maximum value at an optimized Dy3+ ion concentration. Additionally, color-tunable emissions were obtained in Dy3+-activated CaWO4 system by adjusting the Dy3+ ion concentration and excitation wavelength. Ultimately, strong CL properties were observed in Dy3+-activted CaWO4 phosphors. These results suggested that the Dy3+-activted CaWO4 phosphors may have potential applications in the field of miniature color displays.

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Ginsentology II: Chemical Structure-Biological Activity Relationship of Ginsenoside

  • Lee, Byung-Hwan;Nah, Seung-Yeol
    • Journal of Ginseng Research
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    • v.31 no.2
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    • pp.69-73
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    • 2007
  • Since chemical structures of ginsenoside as active ingredient of Panax ginseng are known, accumulating evidence have shown that ginsenoside is one of bio-active ligands through the diverse physiological and pharmacological evaluations. Chemical structures of ginsenoside could be divided into three parts depending on diol or triol ginsenoside: Steroid- or cholesterol-like backbone structure, carbohydrate portions, which are attached at the carbon-3, -6 or -20, and aliphatic side chain coupled to the backbone structure at the carbon-20. Ginsenosides also exist as stereoisomer at the carbon-20. Bioactive ligands usually exhibit the their structure-function relationships. In ginsenosides, there is little known about the relationship of chemical structure and biological activity. Recent reports have shown that ginsenoside $Rg_3$, one of active ginsenosides, exhibits its differential physiological or pharmacological actions depending on its chemical structure. This review will show how ginsenoside $Rg_3$, as a model compound, is functionally coupled to voltage-gated ion channel or ligand-gated ion channel regulations in related with its chemical structure.

Reconstruction of In-beam PET for Carbon therapy with prior-knowledge of carbon beam-track

  • Kim, Kwangdon;Bae, Seungbin;Lee, Kisung;Chung, Yonghyun;An, Sujung;Joung, Jinhun
    • IEIE Transactions on Smart Processing and Computing
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    • v.4 no.6
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    • pp.384-390
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    • 2015
  • There are two main artifacts in reconstructed images from in-beam positron emission tomography (PET). Unlike generic PET, in-beam PET uses the annihilation photons that occur during heavy ion therapy. Therefore, the geometry of in-beam PET is not a full ring, but a partial ring that has one or two openings around the rings in order for the hadrons to arrive at the tumor without prevention of detector blocks. This causes truncation in the projection data due to an absence of detector modules in the openings. The other is a ring artifact caused by the gaps between detector modules also found in generic PET. To sum up, in-beam PET has two kinds of gap: openings for hadrons, and gaps between the modules. We acquired three types of simulation results from a PET system: full-ring, C-ring and dual head. In this study, we aim to compensate for the artifacts that come from the two types of gap. In the case of truncation, we propose a method that uses prior knowledge of the location where annihilations occur, and we applied the discrete-cosine transform (DCT) gap-filling method proposed by Tuna et al. for inter-detector gap.

3D Structure of Bacillus halodurans O-Methyltransferase, a Novel Bacterial O-Methyltransferase by Comparative Homology Modeling

  • Lee, Jee-Young;Lee, Sung-Ah;Kim, Yang-Mee
    • Bulletin of the Korean Chemical Society
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    • v.28 no.6
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    • pp.941-946
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    • 2007
  • Bacillus halodurans O-methyltransferase (BhOMT) is a S-adenosylmethionine (SAM or AdoMet) dependent methyltransferase. Three dimensional structure of the BhOMT bound to S-adenosyl-L-homocysteine (SAH or AdoHcy) has been determined by comparative homology modeling. BhOMT has 40% sequence identity with caffeoyl-CoA 3-O-methyltransferase (CCoAOMT) from alfalfa. Based on x-ray structure of CCoAOMT, three dimensional structure of BhOMT was determined using MODELLER. The substrate binding sites of these two proteins showed slight differences, but these differences were important to characterize the substrate of BhOMT. Automated docking study showed that four flavonoids, quercetin, fisetin, myricetin, and luteolin which have two hydroxyl groups simultaneously at 3'- and 4'-position in the B-ring and structural rigidity of Cring resulting from the double bond characters between C2 and C3, were well docked as ligands of BhOMT. These flavonoids form stable hydrogen bondings with K211, R170, and hydroxyl group at 3'-position in the Bring has stable electrostatic interaction with Ca2+ ion in BhOMT. This study will be helpful to understand the biochemical function of BhOMT as an O-methyltransferase for flavonoids.

A High-Lateral Resolution MALDI Microprobe Imaging Mass Spectrometer Utilizing an Aspherical Singlet Lens

  • Han, Sang Yun;Kim, Hwan Jin;Ha, Tae Kyung
    • Bulletin of the Korean Chemical Society
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    • v.34 no.1
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    • pp.207-210
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    • 2013
  • We report the construction of a MALDI imaging mass spectrometer equipped with a specially designed laser focusing lens, a compact aspherical singlet lens, that obtains a high-lateral imaging resolution in the microprobe mode. The lens is specially designed to focus the ionization laser (${\lambda}$ = 355 nm) down to a $1{\mu}m$ diameter with a long working distance of 34.5 mm. With the lens being perpendicular to the sample surface and sharing the optical axis with the ion path, the imaging mass spectrometer achieved an imaging resolution of as good as $5{\mu}m$ along with a high detection sensitivity of 100 fmol for peptides. The mass resolution was about 900 (m/${\Delta}m$) in the linear TOF mode. The high-resolution capability of this instrument will provide a new research opportunity for label-free imaging studies of various samples including tissues and biochips, even for the study at a single cell level in the future.

Enhancement of NOx photo-oxidation by Fe-doped TiO2 nanoparticles

  • Martinez-Oviedo, Adriana;Ray, Schindra Kumar;Gyawali, Gobinda;Rodriguez-Gonzalez, Vicente;Lee, Soo Wohn
    • Journal of Ceramic Processing Research
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    • v.20 no.3
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    • pp.222-230
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    • 2019
  • Microwave hydrothermal-assisted sol-gel method was employed to synthesize the Fe doped TiO2 photocatalyst. The morphological analysis suggests anatase phase nanoparticles of ~20 nm with an SBET area of 283.99 ㎡/g. The doping of Fe ions in TiO2 created oxygen vacancies and Ti3+ species as revealed through the XPS analysis. The reduction of the band gap (3.1 to 2.8 eV) is occurred by doping effect. The as-prepared photocatalyst was applied for removal of NOx under solar light irradiation. The doping of Fe in TiO2 facilitates 75 % of NOx oxidation efficiency which is more than two-fold enhancement than the TiO2 photocatalyst. The possible reason of enhancement is associated with high surface area, oxygen vacancy, and reduction of the band gap. Also, the low production of toxic intermediates, NO2 gas, is further confirmed by Combustion Ion Chromatography. The mechanism related NOx oxidation by the doped photocatalyst is explained in this study.