S-J. Han

Chosun University, Gwangju, Gwangju, South Korea

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Publications (4)9.36 Total impact

  • W S Ahn · S M Bae · S W Huh · J M Lee · S E Namkoong · S-J Han · C K Kim · J-K Kim · Y-W Kim
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    ABSTRACT: In order to elucidate the antitumor effect of photodynamic therapy (PDT) using the photosensitizing agent hematoporphyrin derivative (Photogem) and a diode laser, we evaluated the cell death of uterine cancer cell lines (CaSki, HT3, HeLa, and SKOV-3) and mice transplanted with TC-1 lung cancer cells. Morphological changes, MTT assay, flow cytometry, cytotoxicity, and tumor growth-inhibition study were evaluated at various time intervals after PDT. The results showed that the survival rates of each cell line decreased with time and dose-response after performing PDT. Also, PDT-induced damage of cancer cells was almost entirely confined to necrosis of the tumor cells in the early time courses. The irradiation of CaSki cells in the presence of Photogem induced plasma membrane disruption and cell shrinkage, indicating the plasma membrane as the main target for Photogem. In the experiment in vivo, the time courses of Photogem with irradiation showed significantly longer survival and a significantly smaller tumor size compared to those in the untreated control groups, and resorption of the tumor after PDT treatment was observed. Collectively, our results indicated that Photogem possesses tumor-specific affinity, and necrosis-like death with plasma membrane damage was postulated to be the principal mechanism of the antitumor effect of PDT using Photogem.
    No preview · Article · May 2004 · International Journal of Gynecological Cancer
  • S-J. Han · T.-H. Jang · YB Kim · B.-G. Park · J.-H. Park · YH Jeong
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    ABSTRACT: Contrasting magnetic properties were obtained from bulk Mn-doped ZnO synthesized under different processing conditions. While a ferrimagnetic phase transition was observable in a Zn0.95Mn0.05O sample processed at 1170 K, no such transition was found for a sample with the same composition processed at 1370 K. The detailed magnetic, structural, and spectroscopic studies of these two samples have revealed that the ferrimagnetic transition in the former sample is attributable to the secondary phase, (Mn,Zn)Mn2O4, in the system. For the latter sample processed at higher temperature, no secondary phase was detected and the major feature of the system remained paramagnetic down to 4 K. The implication of the present results for Mn-doped ZnO thin films is discussed. © 2003 American Institute of Physics.
    No preview · Article · Aug 2003 · Applied Physics Letters
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    S-J. Han · J W Song · C H Yang · S H Park · J H Park · YH Jeong
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    ABSTRACT: Successful synthesis of room-temperature ferromagnetic semiconductors, Zn$_{1-x}$Fe$_{x}$O, is reported. The essential ingredient in achieving room-temperature ferromagnetism in bulk Zn$_{1-x}$Fe$_{x}$O was found to be additional Cu doping. A transition temperature as high as 550 K was obtained in Zn$_{0.94}$Fe$_{0.05}$Cu$_{0.01}$O; the saturation magnetization at room temperature reached a value of $0.75 \mu_{\rm B}$ per Fe. Large magnetoresistance was also observed below $100 $K. Comment: 11 pages, 4 figures; to appear in Appl. Phys. Lett
    Preview · Article · Aug 2002 · Applied Physics Letters
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    S-J Han · C.-W Lee · C.-H Hwang · K.-H Lee · M C Yang · H Kang
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    ABSTRACT: We describe an ion-surface scattering apparatus newly developed to investigate the reactive scattering process of low-energy alkali-metal ions at surfaces. The apparatus consists of an alkali-metal ion gun that is rotatable by 360°, a quadrupole mass spectrometer (QMS) with an ion energy analyzer, a sample manipulator with a heating-and-cooling stage, and an ultrahigh vacuum (UHV) chamber that houses these components. Preliminary experimental results obtained from the apparatus are presented on angular and energy distributions of the ions scattered from clean Pt(111) and water-adsorbed Pt surfaces.
    Preview · Article · Aug 2001 · Bulletin- Korean Chemical Society