Do Yoon Kim

Incheon National University, Sŏul, Seoul, South Korea

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Publications (34)87.47 Total impact


  • No preview · Article · Dec 2015 · Advanced Energy Materials
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    ABSTRACT: Neutrons over a wide range of energies are produced by bombarding a 1.05 cm thick beryllium target with protons of different energies delivered by the MC 50 Cyclotron of the Korea Institute of Radiological Medical Sciences (KIRAMS). The neutron flux Phi(E-n) versus neutron energy E-n produced by protons of 30, 35, and 40 MeV energies, was obtained by using the GEANT4 code with a data based hadronic model. For the experimental validation of the simulated neutron spectra, a number of pure aluminum and iron oxide samples were irradiated with the neutrons produced by 30, 35, and 40 MeV protons at 20 mu A beam current. The gamma ray activities of Na-24 and Mn-56 produced, respectively, through Al-27(n,alpha)Na-24 and Fe-56(n,p)Mn-56 reactions were measured by a HPGe detector. The neutron flux Phi(E-n) at each neutron energy from the simulation was multiplied with the evaluated cross-sections sigma(E-n) of the respective nuclear reaction, and the summation Sigma Phi(E-n)sigma(E-n) was calculated over the neutron spectrum for each proton energy of 30, 35, and 40 MeV. The measured gamma ray activities of Na-24 and Mn-56 were found in good agreement with the activities estimated by using the summed values of Sigma Phi(E-n)sigma(E-n) along with other parameters in a neutron activation method.
    Full-text · Article · Oct 2015 · Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
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    ABSTRACT: Ferromagnetic-like properties of cuprous oxide (Cu2O) are induced through its interaction with chemisorbed surfactant, poly(N-vinyl-2-pyrrolidone) (PVP), which alters the intrinsic d10 configuration of Cu ions. Structural and magnetism-related properties of Cu2O crystals intact (i-Cu2O) and capped with PVP (c-Cu2O) were examined using various analytical instruments. SEM, TEM (corresponding SAED), and XRD of i-Cu2O and c-Cu2O showed cubic and hexagonal shapes of single crystallinity with facets of {200} and {111}, respectively, resulting from the differential growth rates of the original identical crystals along the facets over time. Bulk magnetic susceptibility (χ) of i-Cu2O and c-Cu2O in field-dependent magnetization and the difference in their magnetic moment at room temperature in temperature-dependent magnetization showed diamagnetic and ferromagnetic properties, respectively. The difference in the fluorescence mode of XANES spectra between i-Cu2O and c-Cu2O, showing no quadruple pre-edge peak for the transition of 1s → 3d in Cu (II) ions with d9 electronic configuration, indicates an orbital alteration on the surface of c-Cu2O due to an interaction with PVP. Two peaks for c-Cu2O at higher binding energies in O 1s XPS may be indicative of the ligand to metal charge transfer (LMCT) from O atoms of PVP to Cu ions of Cu2O, generating a chemical interaction through coordination bonding. Large hyperfine splitting constants in electron paramagnetic resonance (EPR) spectra of c-Cu2O support this interpretation, with septet hyperfine splitting suggestive of Cu-Cu interactions on the surface of c-Cu2O via the interaction with O atoms of PVP. These results demonstrate that PVP capping of Cu2O crystal (c-Cu2O) induces ferromagnetism of Cu (I) ions through coordination with O atoms of chemically adsorbed PVP. This may induce LMCT and Cu-Cu interactions that lead to changes in electronic configurations, deriving the ferromagnetic moments of c-Cu2O.
    No preview · Article · May 2015 · The Journal of Physical Chemistry C
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    ABSTRACT: The latent tracks formed on CR-39 solid state track detector on exposure of alpha radiations emanating from a collimated 241Am source were developed by a chemical etching method. Alpha track images were captured by an optical microscope and were processed by using Image Pro-Plus (6.0) software. GEANT4 simulations were carried out to obtain the angular and energy distribution profiles of the alpha particles. Apart from fluence, geometric parameters like aspect ratio (the ratio of the major to minor axis) and the depth profiles of etched tracks were measured experimentally and correlated with simulated angular and energy profile of incident radiations. Reasonable agreement was observed in the fluence and depth profile information obtained from experiments and simulations.
    Full-text · Article · May 2015 · Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms
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    Seung Yeop Oh · Do Yoon Kim · Kwang Wook Suh
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    ABSTRACT: We performed a comparative analysis of the clinicopathologic features and oncologic outcomes of colorectal cancer patients with metachronous versus synchronous metastasis, according to the prognostic factors. Ninety-three patients who underwent curative resection for distant metastatic colorectal cancer were included in the study between December 2001 and December 2011. We assessed recurrence-free survival and overall survival in patients with distant metastasis who underwent curative surgery. The most common site of distant metastasis was lung alone (n = 19, 51.4%) in patients with metachronous metastasis, while liver alone was most common in those with synchronous metastasis (n = 40, 71.4%). Overall survival rate was significantly different between patients with synchronous metastasis and metachronous metastasis (34.0% vs. 53.7%; P = 0.013). Incomplete resection of the metastatic lesion was significantly related to poor overall survival in both, patients with synchronous metastasis, and metachronous metastasis. Our study indicates that patients developing distant metastasis after initial treatment show a different metastatic pattern and better oncologic outcomes, as compared to those presenting with distant metastasis. Resection with tumor free margins significantly improves survival in patients with metachronous as well as synchronous metastasis.
    Preview · Article · May 2015 · Annals of Surgical Treatment and Research
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    ABSTRACT: Recently, we reported n-type graphene can be achieved simply using H2 molecules. It was understood by the attachment of hydrogen atoms dissociated on the surface of graphene. However, the amount of attached hydrogen has not been yet investigated. Here, we show the possibility of the formation of CH bonds due to the H2 exposure theoretically and the mass of the attached hydrogen atoms on graphene experimentally. The amount of the attached hydrogen atoms has been measured by a quartz crystal microbalance (QCM). After exposure of a multilayer graphene (MLG) to 20 bar of H2 pressure at 353 K for 20 h, the resonance frequency (RF) of QCM decreased. It indicates that the mass of the MLG increases. On the basis of the RF variation, we concluded that the hydrogen atoms were bonded to 3.84% of carbon atoms in the MLG. In order to confirm the CH bonding of MLG, Raman spectroscopy was performed before and after exposure to H2 pressure. On exposure, the D peak developed and the peak for 2-D graphite in 2D band increased. The experimental results and theoretical calculation demonstrate that the H2 molecules on the surface of the graphene are dissociated and that some of dissociated H atoms are attached on graphene.
    No preview · Article · Feb 2015 · Synthetic Metals
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    ABSTRACT: The performance and photocatalytic activity of the well-known CdS/ZnO nanorod array system were improved significantly by the layer-by-layer heterojunction structure fabrication of a transparent conductive oxide (TCO) CdO layer on the CdS/ZnO nanorods. Accordingly, a CdO layer with a thickness of approximately 5–10 nm can be formed that surrounds the CdS/ZnO nanorod arrays after annealing at 500 °C under air. At an external potential of 0.0 V vs. Ag/AgCl, the CdO/CdS/ZnO nanorod array electrodes exhibit an increased incident photon to conversion efficiency, which is significantly higher than that of the CdS/ZnO nanorod array electrodes. The high charge separation between the electrons and holes at the interfaces of the heterojunction structure results from the specific band energy structure of the photoanode materials, and the unique high conductivity of the CdO layer is attributed to the suppression of electron–hole recombination; this suppression enhances the photocurrent density of the CdO/CdS/ZnO nanorod arrays. The photoresponse of the electrodes in an electrolytic solution without sacrificial agents indicated that the CdO layer also has the ability to suppress the well-known photocorrosive behavior of CdS/ZnO nanorods.
    Full-text · Article · Dec 2014 · ChemSusChem
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    ABSTRACT: Artemisia montana Pampan (Compositae) (AMP) contains various compounds, including phenolic acids, alkaloids, and essential oil. It has been widely used in oriental medicine due to a variety of biological effects. However, the biological activity of the essential oil from AMP (AMPEO) on skin has not been investigated. In the present study, AMPEO was evaluated for its composition and its effect on cellular events (migration and proliferation) related to skin regeneration using normal human keratinocytes (HaCats). AMPEO, which was extracted by steam distillation, contained 42 components. AMPEO increased proliferation in HaCats in a dose-dependent manner (EC 50, 8.5 ng/mL) and did not affect migration. AMPEO also enhanced the phosphorylation of Akt and ERK 1/2 and induced the synthesis of type IV collagen, but not type I collagen in HaCats. In addition, AMPEO promoted wound closure in the dorsal side skin of rat tail. These results demonstrated that AMPEO extracted by steam distillation induced proliferation and synthesis of type IV collagen in human skin keratinocytes, and may thereby exert positive effects on skin regeneration and wound healing in human skin.
    No preview · Article · Nov 2014 · Natural product communications
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    ABSTRACT: Single crystalline orthorhombic phase tungsten trioxide monohydrate (O-WO3•H2O, space group: Pmnb) nanoplates with clear morphology and uniform size distribution have been synthesized by hydrothermal method, and fabricated on the surface of fluorine doped tin oxide (FTO) coated glass substrates with selective exposure of crystal-facet by finger rubbing method. The rubbing method can easily arrange the O-WO3•H2O nanoplates along (020) facet on FTO substrate. The O-WO3•H2O nanoplate can be converted to monoclinic phase WO3 (γ-WO3, space group: P21/n) with dominant crystal facet of (002) without destroying the plate structure. Crystal morphologies, structures, and components of the films have been determined by SEM, TEM, XRD, Raman, XPS, etc. The band gap energies of the O-WO3•H2O and γ-WO3 nanoplates are determined as ca. 2.26 and 2.49 eV, respectively. Photoelectrochemical properties of the films the films with (002) dominant crystal facet have also been checked for discussion of further application in water oxidation. The advantage of rubbed (020) facet dominant film is investigated by comparing to one spin-coated γ-WO3 thin film with same thickness via photoelectrochemical characterizations such as photocurrent, IPCE and EIS.
    Full-text · Article · Oct 2014 · Crystal Growth & Design
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    ABSTRACT: Purpose Clinical usefulness of sentinel lymph node (SLN) mapping in colorectal cancer remains controversial. The aim of this study is to evaluate the accuracy of the SLN mapping technique using serial sectioning, and to compare the results between ex vivo and in vivo techniques. Methods From February 2011 to October 2012, 34 colon cancer patients underwent SLN mapping during surgical resection. Eleven patients were analyzed with the in vivo method, and 23 patients with the ex vivo method. Patient characteristics and results of SLN mapping were evaluated. Results The SLN mapping was performed in 34 patients. Mean age was 67.3 years (range, 44-81 years). Primary tumors were located in the following sites: 13 in the right colon (38.2%) and 21 in the left colon (61.8%). SLN mapping was performed successfully in 88.2% of the patients. There was no significant difference in the identification rate between the two methods (90.9% vs. 87.0%, P = 1.000). Both the mapping methods showed a low sensitivity and high rate of skip metastasis. Conclusion This study showed that SLN evaluation using serial sectioning could not predict the nodal status with clinically acceptable accuracy despite the high detection rate.
    Preview · Article · Sep 2014 · Annals of Surgical Treatment and Research
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    ABSTRACT: Monte Carlo simulations are performed by using the GEANT4 and the PHITS for studying the neutron-shielding abilities of several materials, such as graphite, iron, polyethylene, NS-4-FR and KRAFTON-HB. As a neutron source, Cf-252 is considered. For the Monte Carlo simulations by using the GEANT4, high precision (G4HP) models with the G4NDL 4.2 based on ENDF/B-VII data are used. For the simulations by using the PHITS, the JENDL-4.0 library is used. The neutron-dose-equivalent rates with or without five different shielding materials are estimated and compared with the experimental values. The differences between the shielding abilities calculated by using the GEANT4 with the G4NDL 4.2 and the PHITS with the JENDL-4.0 are found not to be significant for all the cases considered in this work. The neutron-dose-equivalent rates obtained by using the GEANT4 and the PHITS are compared with experimental data and other simulation results. Our neutron-dose-equivalent rates agree well with the experimental dose-equivalent rates, within 20% errors, except for polyethylene. For polyethylene, the discrepancies between our calculations and the experiments are less than 40%, as observed in other simulation results.
    No preview · Article · Sep 2014 · Journal- Korean Physical Society
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    ABSTRACT: We investigated the effect of essential oil from the flower of Chrysanthemum boreale Makino (CBMEO) on growth of human keratinocytes (HaCaTs) and explored a possible mechanism for this response. CBMEO was extracted using the steam distillation method. CBMEO contained a total of 33 compounds. CBMEO stimulated HaCaT proliferation (EC50, 0.028 μg/mL) and also induced phosphorylation of Akt and ERK1/2 in HaCaTs (EC50, 0.007 and 0.005 μg/mL, for phosphorylated Akt and ERK1/2, respectively). Moreover, CBMEO promoted wound closure in the dorsal side skin of rat tail. This study demonstrated that CBMEO can stimulate growth of human skin keratinocytes, probably through the Akt and ERK1/2 pathways. Therefore, CBMEO may be helpful in skin regeneration and wound healing in human skin, and may also be a possible cosmetic material for skin beauty.
    No preview · Article · Aug 2014 · Natural Product Research
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    ABSTRACT: Purpose Preoperative localization is the most important preparation for laparoscopic surgery. Preoperative marking with India ink has widely been used and is considered to be safe and effective. However, India ink can cause significant inflammation, adhesions and bowel obstruction. Therefore, we have used the patient's blood instead of the ink since 2011. In this retrospective study, we wanted to examine the feasibility of preoperative localization by using the patient's blood. Methods Twenty-five patients who underwent preoperative localization in which 10 mL of their own venous blood was used as a tattooing agent were included in this study. The characteristics of the patients, the anatomy of the colon cancer, and the efficacy and the side effects of using this procedure were analyzed. Results In 23 cases (92%), through the laparoscope, we found perfectly localized bloody smudges in the serosa. However, in 2 cases (8%), we could not find the exact location of the lesion. No patients showed any complications. Conclusion Preoperative localization of early colon cancer or a malignant polyp by using patient's blood is feasible, safe and simple. We think that using the patient's blood for localization of a lesion is better than using some other foreign material such as India ink.
    Preview · Article · Jun 2014 · Annals of Coloproctology
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    ABSTRACT: Metastatic colon cancer patients are treated with the chemotherapy regimens, FOLFOX and FOLFIRI, in either order. So far, we cannot predict the response of chemotherapeutic agent, so it is necessary to find which regimen is adequate before starting chemotherapy. Enrolled patients are randomized into either conventional treatment or planned treatment preceded by pretreatment genetic analysis. Blood samples of patients in planned treatment group (N = 53) were analyzed for the genetic polymorphism before selection of chemotherapeutic agents. Target genes were XPD-751, GSTP-1-105, XRCC1-399 for oxaliplatin, UGT1A1 for irinotecan. The response was measured by computed tomographic scan after completion of three cycles of chemotherapy. Overall response rate was significantly higher in planned group (67.9% vs. 46.3%, P = 0.020). In FOLFOX group, response rate was significantly improved in the planned patients(77.1% vs. 50%, P = 0.018). In FOLFIRI group, the difference didn't reach statistical significance (50% vs. 42.5%, P = 0.776). We found significantly improved response rates in the chemotherapy of metastatic colon cancer by pretreatment genetic analysis, especially in FOLFOX group. J. Surg. Oncol. © 2013 Wiley Periodicals, Inc.
    No preview · Article · Mar 2014 · Journal of Surgical Oncology
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    ABSTRACT: Membranes with nano-apertures are versatile templates that possess a wide range of electronic, optical and biomedical applications. However, such membranes have been limited to silicon-based inorganic materials to utilize standard semiconductor processes. Here we report a new type of flexible and free-standing polymeric membrane with nano-apertures by exploiting high-wettability difference and geometrical reinforcement via multiscale, multilevel architecture. In the method, polymeric membranes with various pore sizes (50-800 nm) and shapes (dots, lines) are fabricated by a hierarchical mould-based dewetting of ultraviolet-curable resins. In particular, the nano-pores are monolithically integrated on a two-level hierarchical supporting layer, allowing for the rapid (<5 min) and robust formation of multiscale and multilevel nano-apertures over large areas (2 × 2 cm(2)).
    No preview · Article · Jan 2014 · Nature Communications
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    ABSTRACT: Background: Little is known of the oncological outcomes after adjuvant FOLFOX chemotherapy in patients with stage III colon cancer showing microsatellite instability high (MSI-H). In the present study we investigated the prognostic impact of MSI-H in patients with stage III colon cancer receiving FOLFOX chemotherapy. Methods: We analyzed the MSI status in 127 patients with stage III colon cancer who underwent curative surgical resection followed by FOLFOX chemotherapy between January 2003 and December 2010. We assessed disease-free and overall survival (OS) in patients with MSI-H colon cancer compared with those showing microsatellite instability low or microsatellite stable (MSI-L/MSS) disease. Results: Sixteen of the patients (12.6 %) were MSI-H, and 111 patients (87.4 %) were MSI-L/MSS. There was no significant difference between patients showing MSI-H and MSI-L/MSS except for age (P = 0.030), tumor location (P < 0.001), and differentiation (P = 0.031). Compared with MSI-L/MSS colon cancer, patients with MSI-H colon cancer had no significant difference in 5-year disease-free and OS (72.2 vs 68.5 %, P = 0.874; 68.1 vs 71.1 %, P = 0.437). Conclusions: Our study indicates that FOLFOX chemotherapy can be considered to treat stage III colon cancer patients with MSI-H after surgery, although the study was not randomized and included only a limited number of patients.
    No preview · Article · Jun 2013 · World Journal of Surgery
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    ABSTRACT: The Korea Rare Isotope Accelerator, currently referred to as KoRIA, is briefly presented. The KoRIA facility is aimed to enable cutting-edge sciences in a wide range of fields. It consists of a 70 kW isotope separator on-line (ISOL) facility driven by a 70 MeV, 1 mA proton cyclotron and a 400 kW in-flight fragmentation (IFF) facility. The ISOL facility uses a superconducting (SC) linac for post-acceleration of rare isotopes up to about 18 MeV/u, while the SC linac of IFF facility is capable of accelerating uranium beams up to 200 MeV/u, 8 pμA and proton beams up to 600 MeV, 660 μA. Overall features of the KoRIA facility are presented with a focus on the accelerator design.
    Full-text · Article · Mar 2013 · Few-Body Systems
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    ABSTRACT: The aim of this study was to investigate the clinical and radiological incidence of parastomal hernia and to analyze the risk factors for parastomal hernia. We reviewed retrospectively 108 patients with end colostomy from January 2003 to June 2010. Age, sex, surgical procedure type, body mass index (kg/m(2)), stoma size, and respiratory comorbidity were documented. There were 61 males (56.5%) and 47 females (43.5%). During an overall median follow-up of 25 months (range, 6 to 73 months), 36 patients (33.3%) developed a radiological parastomal hernia postoperatively and 29 patients (26.9%) presented with a clinical parastomal hernia. In multivariate analysis, gender (odds ratio [OR], 6.087; P = 0.008), age (OR, 1.109; P = 0.009) and aperture size (OR, 6.907; P < 0.001) proved to be significant and independent risk factors after logistic regression analysis. This study showed that the incidence of radiological parastomal hernia is higher than clinical parastomal hernia. Risk factors for parastomal hernia proved to be female, age, and aperture size.
    Preview · Article · Jan 2013 · Journal of the Korean Surgical Society
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    ABSTRACT: Background: The role of neoadjuvant chemotherapy for resectable colorectal liver metastases is a subject of debate. We compared the oncologic outcomes between neoadjuvant chemotherapy and adjuvant chemotherapy combined with surgery for resectable synchronous colorectal liver metastases. Methods: We analyzed 30 patients who underwent liver resection for resectable colorectal liver metastases combined with oxaliplatin-based neoadjuvant or adjuvant chemotherapy between May 2003 and August 2010. We assessed recurrence-free and overall survival in patients treated using neoadjuvant chemotherapy compared with those who received adjuvant chemotherapy. Results: Of the 30 patients with colorectal liver metastases, 15 underwent neoadjuvant chemotherapy and 15 underwent adjuvant chemotherapy. Nine (60%) patients in the adjuvant group relapsed and nine (60%) patients in the neoadjuvant group relapsed. The neoadjuvant chemotherapy group had no significant difference in recurrence-free and overall 3-y survival (37.5% versus 45.0%, P = 0.938; 44.0% versus 66.7 %, P = 0.466) compared with the adjuvant chemotherapy group. Conclusion: Our results indicate that neoadjuvant chemotherapy is not inferior to adjuvant chemotherapy for resectable colorectal liver metastases, although the study was not randomized and included a limited number of patients.
    No preview · Article · Nov 2012 · Journal of Surgical Research
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    ABSTRACT: The interesting electrochemical performances and magnetic properties of hierarchical NiO hollow microspheres were investigated. A rational formation mechanism of NiO hollow spheres from Ni(OH)2 was proposed on the basis of agglomerated-mediated growth.
    No preview · Article · Oct 2012 · RSC Advances

Publication Stats

264 Citations
87.47 Total Impact Points

Institutions

  • 2015
    • Incheon National University
      • Department of Physics
      Sŏul, Seoul, South Korea
  • 2012-2015
    • Sogang University
      • Department of Chemistry
      Sŏul, Seoul, South Korea
    • University of Ulsan
      Ulsan, Ulsan, South Korea
  • 2006-2015
    • Ajou University
      • • Department of Surgery
      • • Department of Medicine
      Sŏul, Seoul, South Korea
    • Yale University
      New Haven, Connecticut, United States
  • 2003-2015
    • Sungkyunkwan University
      • Department of Physics
      Sŏul, Seoul, South Korea
  • 2014
    • Hoseo University
      • College of Natural Sciences
      Onyang, Chungcheongnam-do, South Korea
    • Gachon University
      • College of BioNano Technology
      Sŏngnam, Gyeonggi Province, South Korea
  • 2008
    • Yonsei University
      • Department of Medical Engineering
      Sŏul, Seoul, South Korea
  • 2007-2008
    • Seoul National University
      • • Research Institute of Pharmaceutical Sciences
      • • College of Pharmacy
      Sŏul, Seoul, South Korea
    • Ajou University Medical Center
      수원시, Gyeonggi-do, South Korea