• Title/Summary/Keyword: Forster

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Spectroscopic investigations on the interaction of bovine serum albumin with amoxicillin and cloxacillin

  • BHALCHANDRA P. KAMAT,
    • Journal of Photoscience
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    • v.12 no.1
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    • pp.11-15
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    • 2005
  • The mechanism of interaction of two drugs viz., amoxicillin and cloxacillin with bovine serum albumin has been investigated using fluorescence absorption and circular dichroism spectroscopy. The quenching mechanism of fluorescence of bovine serum albumin by amoxicillin and cloxacillin was discussed. The binding sites number n and apparent binding constant Kwere measured by fluorescence quenching method. The thermodynamic parameters obtained from data at different temperatures were calculated. The distance r between donor (bovine serum albumin) and acceptor (amoxicillin and cloxacillin) was obtained according to Forster theory of non-radiative energy transfer. The effect of common ions on binding constant was also investigated. The results of synchronous fluorescence spectra, UV-vis absorption spectra and circular dichroism of BSA in presence of amoxicillin and cloxacillin show that the conformation of bovine serum albumin changed

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Proton Transfer Equilibria in The Excited State of Piroxicam and Its Analog in Aqueous Solution

  • Yoon, Min-Joong;Kim, Yong-Hee
    • Bulletin of the Korean Chemical Society
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    • v.10 no.5
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    • pp.434-437
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    • 1989
  • The pH dependence of the absorption and fluorescence of 4-hydroxy-2-methyl-1,2-benzothiazinenecarboxylat es, piroxicam and HMBDC have been measured and compared with the solvent dependence of the spectra reported previously. Four different prototropic species are observed in both ground and excited states of piroxicam ; the cation, the neutral, the anion and the dianion, while three different species such as the cation, the neutral and the anion are observed in HMBDC. The $pK_a$ and $pK_a^{\ast}$ have been determined by absorptiometric titration and Forster cycle method, respectively. The probable structure of each species has been proposed on the basis of the intramolecular phototautomerism.

Transfer of Electronic Excitation Energy in Poltstyrene Films Doped with an Intramolecular Proton Transfer Compound

  • 강태종;김학진;정진갑
    • Bulletin of the Korean Chemical Society
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    • v.17 no.7
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    • pp.616-621
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    • 1996
  • The transfer of excitation energy from solvent to solute in polystyrene films doped with 2-(2'-hydroxyphenyl)benzothiazole (HBT) which undergoes intramolecular proton transfer in excited electronic state has been studied by employing steady state and time-resolved fluorescence measurements. The degree of Forster overlap between donor and acceptor molecule in this system is estimated to be moderate. Energy transfer efficiency increases with solute concentration at low concentration range and levels off at high concentration. It is observed that the excimer form of polystyrene is largely involved in energy transfer process. Photostability of HBT in polystyrene to UV light is also investigated to get insight into the long wavelength absorption band of HBT which was observed upon electron radiation.

Description of a new species of the genus Venturia Schrottky (Hymenoptera: Ichneumonidae: Campopleginae) from South Korea

  • Choi, Jin-Kyung
    • Journal of Species Research
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    • v.11 no.2
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    • pp.128-131
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    • 2022
  • A new species, Venturia tenuiabdominalis Choi sp. nov., belonging to the subfamily Campopleginae, family Ichneumonidae, is described in South Korea. The subfamily Campopleginae was recorded by Forster in 1869 based on genus Campoplex and more than 2,100 described species into 66 genera have been reported worldwide. Among the 66 genera of Campopleginae, the genus Venturia is one of the large groups, which is more than 140 species worldwide (Yu et al., 2016; Vas, 2019a; 2019b; Vas, 2020; Vas and Di Giovanni, 2020; Han et al., 2021). A taxonomic study of South Korean Venturia was initiated by Choi et al. (2012), who reported Venturia longipropodeum (Uchida, 1942). A key to species of South Korean Venturia, description of new species and diagnostic illustrations are provided.

Endothermic Forster Energy Transfer from DPVBi to BCzVBi in High Efficient Blue Organic Light-Emitting Diodes (고효율 청색 유기발광다이오드의 DPVBi와 BCzVBi 사이에서 발생하는 흡열 페르스터 에너지전이)

  • Kim, You-Hyun;Lee, Sang-Youn;Song, Wook;Shin, Sung-Sik;Ryu, Dae-Hyun;Wood, Richard;Yatulis, Jay;Kim, Woo-Young
    • Journal of the Korean Chemical Society
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    • v.54 no.3
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    • pp.291-294
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    • 2010
  • In this study, we demonstrated high-efficiency blue organic light-emitting diodes (OLEDs) employing BCzVBi as a blue fluorescent dye doped into blue host material, DPVBi with various concentration. The optimized blue OLED device having high-efficiency was constructed with structure of NPB (500 ${\AA}$) / DPVBi:BCzVBi-6% (150 ${\AA}$)/$Alq_3$(300 ${\AA}$) / Liq (20 ${\AA}$) / Al (1000 ${\AA}$). The maximum luminescence of blue OLED was 13200 cd/$m^2$ at 13.8 V and current density and maximum efficiency were 26.4 mA/$cm^2$ at 1000 cd/$m^2$ and 4.24 cd/A at 3.9 V, respectively. Luminous efficiency shows two times higher than comparing with non-doped BCzVBi blue OLED whereas $CIE_{x,y}$ coordinate was similar with bare DPVBi blue OLED such as (0.16, 0.19). Electroluminescence of BCzVBi-6% doped blue OLED has two major peaks at 445 nm and 470 nm whereas pure DPVBi's blue peak appears at 456 nm and it is happened through endothermic Forster energy transfer by molecule's vibration between LUMO of DPVBi as host material and LUMO of BCzVBi as dopant in device.

Task Review of INEX Book Search Track (INEX Book Search 트랙의 실험 고찰)

  • Park, Mi-Sung
    • Journal of Korean Library and Information Science Society
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    • v.40 no.4
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    • pp.199-225
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    • 2009
  • The purpose of this paper is to grow more interest and to forster research in full-texts retrieval of digitized books area through the review of Book Search Track and the analysis of research methods. First, this paper introduces the INEX tracks, the registration of INEX, the task process and the participating organizations. Second, to introduce the Book Search Track of all INEX tracks, this paper provides an overview of the test collection, the tasks, the task and submission guidelines and evaluation results of the Book Search Track's. Third, through paper review of the Book Search track that was lunched in 2007 as part of the INEX initiative, this paper presents the future research subject. This study expects that the readers are attracted by INEX tracks and full-texts retrieval of digitized books in korea.

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Characterization of the Four GH12 Endoxylanases from the Plant Pathogen Fusarium graminearum

  • Habrylo, Olivier;Song, Xinghan;Forster, Anne;Jeltsch, Jean-Marc;Phalip, Vincent
    • Journal of Microbiology and Biotechnology
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    • v.22 no.8
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    • pp.1118-1126
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    • 2012
  • Four putative GH12 genes were found in the Fusarium graminearum genome. The corresponding proteins were expressed in Escherichia coli, purified, and evaluated. FGSG_05851 and FGSG_11037 displayed high activities towards xyloglucan ($V_{max}$ of 4 and $11{\mu}mol/min$, respectively), whereas FGSG_07892 and FGSG_16349 were much less active with this substrate (0.081 and $0.004{\mu}mol/min$, respectively). However, all four of these enzymes had a similar binding affinity for xyloglucan. Xyloglucan was the substrate preferred by FGSG_05851, in contrast to the three other enzymes, which preferred ${\beta}$-glucan or lichenan. Therefore, FGSG_05851 is a xyloglucan-specific glucanase (E.C. 3.2.1.151) rather than an endoglucanase (E.C. 3.2.1.4) with broad substrate specificity. FGSG_11037 displayed a peculiar behavior in that the xyloglucan binding was highly cooperative, with a Hill coefficient of 2.5. Finally, FGSG_05851 essentially degraded xyloglucan into hepta-, octa-, and nonasaccharides, whereas the three other enzymes yielded hepta- and octa-saccharides as well as larger molecules.

A Study on characteristic of sustainable design of architectural space on Norman Foster's works (Norman Foster의 건축 공간에 나타난 지속 가능한 디자인 특성에 관한 연구)

  • Kweon, Yeong-Jae;Kim, Jung-Shin
    • Korean Institute of Interior Design Journal
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    • v.18 no.4
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    • pp.11-20
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    • 2009
  • Norman Foster has done about 300 projects over the world and has been understood as a global architect for sustainable design on various areas including urban design, architecture, interior, transport and furniture. The trend of Forster's work which had been changed positively as experimental trials from 1960 has established his design trend for sustainable design. The characteristics of Norman Foster's sustainable design leading the trend of contemporary architecture over the limit of the high-tech architecture is researched through the project report, literature, field study and interview based on sustainability aspects which are social, environment and economy especially. For systematic classification and modern analysis of Norman Foster's architecture, the research is analyzed architectural characteristics on case works focused on architecture and urban design after the middle of 1980 when Norman Foster's sustainable design was emerged clearly. Consequently, the research could be a substantial process for understanding sustainable design as current outstanding ideas which makes Norman Foster overcome his limit of Post-high tech architecture through looking at his spatial identity.

InP Quantum Dot - Organosilicon Nanocomposites

  • Dung, Mai Xuan;Mohapatra, Priyaranjan;Choi, Jin-Kyu;Kim, Jin-Hyeok;Jeong, So-Hee;Jeong, Hyun-Dam
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.191-191
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    • 2012
  • InP quantum dot (QD) - organosilicon nanocomposites were synthesized and their photoluminescence quenching was mainly investigated because of their applicability to white LEDs (light emitting diodes). The as-synthesized InP QDs which were capped with myristic acid (MA) were incompatible with typical silicone encapsulants. Post ligand exchange the MA with a new ligand, 3-aminopropyldimethylsilane (APDMS), resulted in soluble InP QDs bearing Si-H groups on their surface (InP-APDMS) which allow embedding the QDs into vinyl-functionalized silicones through direct chemical bonding, overcoming the phase separation problem. However, the ligand exchange from MA to APDMS caused a significant decrease in the photoluminescent efficiency which is interpreted by ligand induced surface corrosion relying on theoretical calculations. The InP-APDMS QDs were cross-linked by 1,4-divinyltetramethylsilylethane (DVMSE) molecules via hydrosilylation reaction. As the InP-organosilicon nanocomposite grew, its UV-vis absorbance was increased and at the same time, the PL spectrum was red-shifted and, very interestingly, the PL was quenched gradually. Three PL quenching mechanisms are regarded as strong candidates for the PL quenching of the QD nano-composites, namely the scattering effect, Forster resonance energy transfer (FRET) and cross-linker tension preventing the QD's surface relaxation.

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The Synthesis and Optical Properties of Silica Coated CdSe/ZnS QDs (실리카가 코팅된 양자점의 코팅두께에 따른 광 특성 변화)

  • Lee, Ji-Hye;Shin, Hyun Ho;Lee, Jong-Heun;Hyun, Sang Il;Koo, Eunhae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.3
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    • pp.221-226
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    • 2013
  • The water soluble quantum dots (QDs) are synthesized by the phase transfer and silica coating reaction. The photoluminescence intensity of silica-coated QDs are mainly affected by the amount of phase transfer agent, SDS (sodium dodecyl sulfate), and the maximum value is obtained at the cmc (critical micell concentration) concentration of SDS in the phase transfer reaction. Based on fluorescence spectra and field emission transmission electron microscope (FETEM), the energy transfer rate by forster resonance energy transfer (FRET) is increasing with the thickness of the silica shell coated on CdSe/ZnS QDs.