• Title/Summary/Keyword: LIF

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Visualization of Breakup and Atomization Processes in Non-evaporating Diesel Sprays (비증발 디젤분무의 분열과 미립화 과정의 가시화)

  • 원영호;김우태
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.1
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    • pp.25-31
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    • 2004
  • Two-dimensional laser visualization methods have been used in the study of breakup and atomization processes of non-evaporating diesel sprays. A single-hole spray injected into a quiescent atmospheric environment was visualized by the LIF(Laser Induced Fluorescence) and scattering technique. The LIF technique could be implemented to take the images which are magnified enough to show the shape of liquid ligaments and small droplets. The spontaneous scattering and fluorescent images of sprays were also taken to investigate the atomization of droplets. In the tip and periphery of a spray. the scattering light is bright and the ratio of fluorescent/scattering intensity is lower. This characteristics indicate the very high number density of small droplets which are well atomized.

Measurement of a Pulsed Jet with High-Definition 3D-PTV (고해상 3차원 PTV에 의한 돌발분류구조 계측)

  • Doh Deog-Hee;Hwang Tae-Kue;Cho Yong-Beom;Pyeon Yong-Beom;Kobayashi Toshio;Tetsuo Saga
    • 한국가시화정보학회:학술대회논문집
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    • 2002.11a
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    • pp.43-44
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    • 2002
  • A pulsed jet was measured with high-definition 3D-PTV technique. The measurement system consists of three CCD cameras, Ar-ion laser, an image grabber and a host computer. Two fitness functions were introduced in a genetic algorithm in order to enhance the correspondences of the particles. One was based on a concept of the continuum theory and the other one was based on a minimum distance error. The head vortex of the jet was visualized by LIF and was reconstructed by the constructed high-resolution 30-PTV system for comparisons.

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Supersonic Free Jet and Ab initio Studies of Electronic-Vibrational Structures of Fluorene

  • 부봉현;최영식;김택수;강성권;김재룡
    • Bulletin of the Korean Chemical Society
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    • v.16 no.4
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    • pp.341-344
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    • 1995
  • Laser-induced fluorescence (LIF) excitation spectra were measured for fluorene (FR) cooled in pulsed supersonic expansions of He in the range 283.7-296.7 nm. Ab initio studies of FR have also been carried out for determining the electronic and vibrational structures by using the standard 3-21G basis sets. In the LIF excitation spectra of FR, highly resolved vibronic bands are observed having the band origin of 33,791 cm-1. The vibrational bands above the electronic origin were assigned on the basis of the well-characterized electronic vibrational bands reported previously and of normal modes of vibrations derived by our HF/3-21G calculations.

Numerical Simulation for Near Field-Behavior of Wastewater Discharged into Stagnant Ambient in Coastal Region (연안지역의 정체수역에서 방류되는 하$\cdot$폐수의 근역거동 수치모의)

  • Kwon, Seok-Jae;Seo, Il-Won
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.17 no.3
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    • pp.166-177
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    • 2005
  • This study developed the jet integral model to analyze the behavior of the wastewater discharge in the near field using the fourth order Runge-Kutta method in order to numerically solve the problems of six ordinary differential equations and six unknowns. This jet integral model used the entrainment hypothesis and the manipulation of sonle shape constant. This study also conducted the hydraulic experiments fnr single horizontal buoyant Jet using LIF through the calibration procedure. The results calculated by the previous models, CORMIX 1 and VISJET, and the proposed jet integral model were compared to the hydraulic experimental results. The centerline trajectories predicted by the proposed model were in good agreements with the experimental results in the transition region whereas the trajectories calculated by the VISJET model agreed well with the measured data in the momentum and buoyancy-dominated regions. The centerline dilution calculated by the proposed model agreed generally with the measured dilution in the intial and transition regions while the centerline dilution predicted by the CORMIX 1 was in good agreements with the experimental results in the momentum and buoyancy-dominated regions.

Benzoic Acid Enhances Embryo Implantation through LIF-Dependent Expression of Integrin αVβ3 and αVβ5

  • Choi, Hee-Jung;Chung, Tae-Wook;Park, Mi-Ju;Kim, Hyung Sik;You, Sooseong;Lee, Myeong Soo;Joo, Bo Sun;Lee, Kyu Sup;Kim, Keuk-Jun;Wee, Gabbine;Kim, Choong-Yong;Kim, Cheorl-Ho;Ha, Ki-Tae
    • Journal of Microbiology and Biotechnology
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    • v.27 no.4
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    • pp.668-677
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    • 2017
  • Embryo implantation is the crucial step for a successful pregnancy. Diverse factors, including adhesion molecules, growth factors, and cytokines are important for embryo implantation through improving endometrial receptivity. Benzoic acid (BA), a component of various plants, has been shown to have antifungal and antioxidant effects. However, the effect of BA on embryo implantation remains unknown. Here, we showed the contribution of BA for the enhancement of endometrial receptivity through the leukemia inhibitory factor (LIF)-dependent increase of integrin ${\alpha}V$, ${\beta}3$, and ${\beta}5$ expression. Furthermore, in vivo study using a mifepristone-induced implantation failure model showed that BA definitely improves the numbers of implantation embryos. Taken together, we suggest that BA has a novel function for embryo implantation through the up-regulation of LIF-mediated integrins, and may be a candidate for therapeutic medicine to increase the pregnancy rate.

Damaged Neuronal Cells Induce Inflammatory Gene Expression in Schwann Cells: Implication in the Wallerian Degeneration

  • Lee, Hyun-Kyoung;Choi, Se-Young;Oh, Seog-Bae;Park, Kyung-Pyo;Kim, Joong-Soo;Lee, Sung-Joong
    • International Journal of Oral Biology
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    • v.31 no.3
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    • pp.87-92
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    • 2006
  • Schwann cells play an important role in peripheral nerve regeneration. Upon nerve injury, Schwann cells are activated and produce various proinflammatory mediators including IL-6, LIF and MCP-1, which result in the recruitment of macrophages and phagocytosis of myelin debris. However, it is unclear how the nerve injury induces Schwann cell activation. Recently, it was reported that necrotic cells induce immune cell activation via toll-like receptors (TLRs). This suggests that the TLRs expressed on Schwann cells may recognize nerve damage by binding to the endogenous ligands secreted by the damaged nerve, thereby inducing Schwann cell activation. To explore the possibility, we stimulated iSC, a rat Schwann cell line, with damaged neuronal cell extracts (DNCE). The stimulation of iSC with DNCE induced the expression of various inflammatory mediators including IL-6, LIF, MCP-1 and iNOS. Studies on the signaling pathway indicate that $NF-{\kappa}B$, p38 and JNK activation are required for the DNCE-induced inflammatory gene expression. Furthermore, treatment of either anti-TLR3 neutralizing antibody or ribonuclease inhibited the DNCE-induced proinflammatory gene expression in iSC. In summary, these results suggest that damaged neuronal cells induce inflammatory Schwann cell activation via TLR3, which might be involved in the Wallerian degeneration after a peripheral nerve injury.