• Title/Summary/Keyword: Molecular Analysis

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Simulation of Molecular Flows Inside a Guide Block in the OLED Deposition Process (OLED 박막 증착공정에서 유도로 내부의 분자유동 해석)

  • Sung, Jae-Yong;Lee, Eung-Ki
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.2
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    • pp.45-50
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    • 2008
  • Molecular flows inside a guide block in the OLED(organic luminescent emitting device) deposition process have been simulated using DSMC(direct simulation Monte Carlo) method. Because the organic materials are evaporated under vacuum, molecules flow at a high Knudsen number of the free molecular regime, where the continuum mechanics is not valid. A guide block is designed as a part of the linear cell source to transport the evaporated materials to a deposition chamber, When solving the flows, the inlet boundary condition is proved to affect significantly the whole flow pattern. Thus, it is proposed that the pressure should be specified at the inlet. From the analysis of the density distributions at the nozzle exit of the guide block, it is shown that the longer nozzle can emit molecules more straightly. Finally, a nondimensionalized mass flow profile is obtained by numerical experiments, where various nozzle widths and inlet pressures are tested.

Five New Stilbenes from the Stem Bark of Artocarpus communis

  • Chan, Susanna T.S.;Popplewell, Wendy L.;Bokesch, Heidi R.;McKee, Tawnya C.;Gustafson, Kirk R.
    • Natural Product Sciences
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    • v.24 no.4
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    • pp.266-271
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    • 2018
  • Five new prenylated stilbenes (1 - 5), along with the known compounds cudraflavone C, trans-4-isopentenyl-3,5,2',4'-terahydroxystilbene, trans-4-(3-methyl-E-but-1-enyl)-3,5,2',4'-tetrahydroxystilbene, pannokin G, cycloartobiloxanthone, artonin P, morusin, artocarpin, artonin E, kuwanon C, artobiloxanthone, and artoindonesianin C (6 - 17) were isolated from the stem bark of the tropical tree Artocarpus communis. The structures were established by NMR spectroscopic analysis, MS studies, and comparison with spectral data reported in the literature.

ErbB3 binding protein 1 contributes to adult hippocampal neurogenesis by modulating Bmp4 and Ascl1 signaling

  • Youngkwan Kim;Hyo Rim Ko;Inwoo Hwang;Jee-Yin Ahn
    • BMB Reports
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    • v.57 no.4
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    • pp.182-187
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    • 2024
  • Neural stem cells (NSCs) in the adult hippocampus divide infrequently; the endogenous molecules modulating adult hippocampal neurogenesis (AHN) remain largely unknown. Here, we show that ErbB3 binding protein 1 (Ebp1), which plays important roles in embryonic neurodevelopment, acts as an essential modulator of adult neurogenic factors. In vivo analysis of Ebp1 neuron depletion mice showed impaired AHN with a low number of hippocampal NSCs and neuroblasts. Ebp1 leads to transcriptional repression of Bmp4 and suppression of Ascl1 promoter methylation in the dentate gyrus of the adult hippocampus reflecting an unusually high level of Bmp4 and low Ascl1 level in neurons of Ebp1-deficient mice. Therefore, our findings suggests that Ebp1 could act as an endogenous modulator of the interplay between Bmp4 and Ascl1/Notch signaling, contributing to AHN.

Molecular Properties of Streptococcal Nuclease Isolated from Streptococcus sp.

  • Song, Kyung-Bin;Lee, Min-Jung
    • Journal of Microbiology and Biotechnology
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    • v.4 no.4
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    • pp.364-366
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    • 1994
  • Molecular properties of streptococcal nuclease purified from Streptococcus sp. were examined. The purified enzyme was stable in the range of pH 7 to 10 and easily inactivated above $60^{\circ}C$. Atomic spectroscopy analysis indicated that the enzyme contains Ca, Mg, Zn. Circular dichroism study showed 25% $\alpha$ -helix, 15% $\beta$-sheet and 30% $\beta$-tums.

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