Sung Kil Kang

Pohang University of Science and Technology, Geijitsu, Gyeongsangbuk-do, South Korea

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Publications (16)28.49 Total impact

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    ABSTRACT: Using Ar/Air mixture microwave plasma, we investigated the effects of air and gas temperature on the generation of electrons, ozone (O3), and nitric oxide (NO) through experiments and chemical kinetics simulation. The global model (GM) chemical kinetics simulation was used to validate and complement experimental observations. As the air percentages in Ar plasma increase, electrons are mainly generated by reactive oxygen species (ROS), but electron densities decrease. This is why plasma jet length becomes shorter with the mixture of air to Ar plasma at the same power. The profile of O3 densities has a maximum point because these are affected by oxygen (O2) molecules and gas temperature. O3 densities increase because these are generated via recombination of atomic oxygen (O) and O2 radicals as the air percentages increase. As the gas temperature increases, O3 densities decrease and O3 radicals are mainly destroyed by ROS such as O2−, excited O2, and O, although air percentages increase. NO radicals increase continually with the addition of air mixture and increase in gas temperature. With respect to biomedical applications, in the case of Ar/Air plasma treatment, it takes just 2 d, which has reduced the wound area to 30% because of faster scab formation over the wound and mRNA activation. Abundant NO radicals with ROS in Ar/aAir plasma strongly enhance IL-6 and TGF-β1, which facilitate collagen remodeling and wound recovery effectively.
    Plasma Processes and Polymers 04/2015; DOI:10.1002/ppap.201500017 · 2.96 Impact Factor
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    ABSTRACT: A 1.29-GHz microwave excited atmospheric pressure ambient air plasma jet has been developed as a portable plasma device. A 10-mm stable air plasma jet was generated with a pin-to-hole structure coaxial resonator. Ozone problem was also solved by high temperature of the formed air plasma. Appropriate ambient air flow was supplied to reduce the plasma gas temperature up to 36 °C at treating point. The ozone-free nonthermal portable air plasma system is expected to be useful in biomedical area for its components investigated by optical emission analysis.
    IEEE Transactions on Plasma Science 10/2014; 42(10):2788-2789. DOI:10.1109/TPS.2014.2320266 · 0.95 Impact Factor
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    ABSTRACT: Using surface type air atmospheric pressure plasma, we investigated the amount of ozone and other reactive species generation with variations of the surface temperature of an electrode through an optical emission spectrum and a tube type gas detector. Reduced version of global model (GM) was employed to complement these experimental observations. The results of the model matched well with the experimental data. The amount of ozone generated from the surface type air plasma device was dramatically reduced with increasing temperature. Atomic oxygen (O) and nitric oxide (NO) radicals, which are important agents for biomedical applications, proportionally increased with increasing temperature. We also elucidated the dominant reaction related to the generation or loss of these radicals based on temperature variation through our GM.
    Plasma Processes and Polymers 08/2013; 10(8). DOI:10.1002/ppap.201200163 · 2.96 Impact Factor
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    ABSTRACT: Surface tissue-removal mechanisms, resulting from atmospheric He-H2O2 plasma jet fluxes impinging on tissue surfaces, were investigated. We employed primarily optical emission for cataloging relative concentrations of reactive plasma radicals versus plasma-jet conditions. The reactive radicals were then correlated with measured tissue-removal rates, under varying experimental conditions to determine the dominant role of OH radicals in the tissue removal. Fourier transform infrared (FTIR) molecular spectroscopy was employed to track molecular bond alterations at tissue surfaces, following the plasma irradiation of tissue surfaces. We studied three types of samples: 1) volatilized tissue fragments, filtered out of the effluent; 2) remaining solid-phase tissue samples in the incision region; and 3) nonprocessed contiguous tissue-surface regions. All surface bondings were compared and contrasted by FTIR analysis. In parallel, both the pure electro surgery (ES) with no added plasma radical fluxes and plasma-assisted ES were used as a dual baseline. This three-part study provides evidence that OH radicals drive the observed changes on tissue surfaces both within, and in bordering tissue regions in a He-H2O2 atmospheric plasma jet. Moreover, plasma-assisted ES as compared to pure ES reduces buildup of tissue char on the ES device electrodes, which is a practical advantage in ES surgery. FTIR measurement of the surgical margins (surrounding the removed tissue) is possible in pure plasma-jet tissue removal, via measuring changes in amide A bonds, which are indicators of the level of thermal damage to surrounding tissue, and may be a possible control means to achieve minimum collateral damage.
    IEEE Transactions on Plasma Science 04/2013; 41(4):907-914. DOI:10.1109/TPS.2013.2251906 · 0.95 Impact Factor
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    ABSTRACT: form only given. Microwave plasma technique for biomedical applications has been studied and applied to several fields such as blood coagulation and sterilization. The microwave plasmas generally showed high electron temperature and high electron density, consequently the gas temperature higher than low frequency plasmas. For biomedical applications, especially for human body, it is required to have low temperature and high concentration of reactive species. Pulse modulation technique is one of possible methods to achieve the needs. Finger-size microwave generator and pulsed microwave power module using palm-size power module were developed. Gas temperature and emission spectra were measured with several duty ratios and a fixed average power. Gas temperature of Ar and Air plasmas reduced as the duty ratio reduced. In the case of Air plasma, the gas temperature reduced from 100° C to ~55° C. This caused by off-phase of the pulse modulated signal which was proportional to the reduction of duty ratio. On the other hand, the portion of reactive species including O and OH increased as the duty ratio reduced. This related to the momentary high power excitation. The technique embedded to a skin care system (Medipl Corp.) and blood coagulation experiment was conducted. While natural coagulation time was about 18 min, treated blood drops were coagulated in 2.5 min. Numerical analysis such as global and fluid modeling will also be presented.
    Plasma Science (ICOPS), 2013 Abstracts IEEE International Conference on; 01/2013
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    ABSTRACT: Electrosurgery (ES) is widely used by surgeons to dissect tissue and control bleeding. Electrosurgical devices achieve these effects through resistive heating of tissue that vaporizes cellular fluid to rupture cells and denatures proteins to produce a hemostatic coagulum. In this paper, the powered electrode of a 13.56?MHz atmospheric pressure plasma jet was employed in contact with tissue samples to vaporize or ablate tissue. In effect, monopolar ES was combined with plasma. We report both significantly higher tissue removal rate and lower electrical current flow through the tissue sample with plasma-assisted ablation compared to conventional electrosurgical ablation at the same generator output power.
    Plasma Processes and Polymers 10/2012; 9(10). DOI:10.1002/ppap.201200003 · 2.96 Impact Factor
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    ABSTRACT: Energy-based surgical devices are widely used to fuse tissues and seal vessels, but tissue adhesion to the instrument complicates the procedure. We deposit a robust non-stick coating on the jaws of LigaSureTM tissue fusion devices by employing an atmospheric pressure RF-driven plasma with hexamethyldisiloxane (HMDSO) entrained in argon carrier gas. The hydrophobicity, surface energy, surface topography, and chemical characteristics of deposited films are characterized by water contact angle measurements, surface energy test pens, atomic force microscopy, and Fourier transform infrared spectroscopy, respectively. We demonstrate significantly reduced tissue adhesion to HMDSO polymer film-coated instruments during the tissue fusion procedure in comparison with uncoated and chromium nitride-coated instruments.
    Plasma Processes and Polymers 04/2012; 9(4). DOI:10.1002/ppap.201100155 · 2.96 Impact Factor
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    ABSTRACT: Unique striations were observed in the formation of 900-MHz microwave argon atmospheric-pressure plasma jet in air. The striated patterns are easily observed even with the naked eyes at a flow rate of above 3 slm and an input power of below 3 W. Moreover, the striated patterns, which were associated with shortening in the plasma jet length, are obtained by adding less than 1 vol.% of O2 gas to Ar. Index Terms—Droplet striation patterns, intensified charge- coupled device (ICCD) image, microwave argon atmospheric- pressure plasma jet.
    IEEE Transactions on Plasma Science 11/2011; 39(11):2318-2319. DOI:10.1109/TPS.2011.2128343 · 0.95 Impact Factor
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    ABSTRACT: We demonstrated bacterial (Streptococcus mutans) inactivation by a radio frequency power driven atmospheric pressure plasma torch with H2O2 entrained in the feedstock gas. Optical emission spectroscopy identified substantial excited state •OH generation inside the plasma and relative •OH formation was verified by optical absorption. The bacterial inactivation rate increased with increasing •OH generation and reached a maximum 5-log10 reduction with 0.6% H2O2 vapor. Generation of large amounts of toxic ozone is drawback of plasma bacterial inactivation, thus it is significant that the ozone concentration falls within recommended safe allowable levels with addition of H2O2 vapor to the plasma.
    Applied Physics Letters 04/2011; 98(14):143702-143702-3. DOI:10.1063/1.3574639 · 3.52 Impact Factor
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    ABSTRACT: A portable microwave-excited atmospheric pressure plasma jet (APPJ) using a coaxial trans-mission line resonator is introduced for applications of plasma biomedicine. Its unique feature includes the portability and no need for matching network and cooling system with high power efficiency, operating at 900 MHz with low ignition power less than 2.5 W in argon at atmospheric pressure. The temperature at the downstream of the APPJ stays less than 470°C (≈320 K) during 5 min of continuous operation. The optical emis-sion spectrum of the APPJ shows various reactive radicals such as OH, NO, and O which are respon-sible for biomedicine. The APPJ was applied to investigate the acceleration of blood coagulation, which occurred within 20 s of plasma treatment in vitro and within 1 min in vivo. This is significantly faster than the natural coagulation.
    Plasma Processes and Polymers 03/2010; 7(3‐4):258 - 263. DOI:10.1002/ppap.200900079 · 2.96 Impact Factor
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    ABSTRACT: It is known that early childhood wheezing associated with sensitization to allergens, including food, has an increased risk of developing asthma later during school age. Gastroesophageal reflux (GER) is well known to be associated with asthma. The purpose of this study was to determine whether there is an association between silent GER and food sensitization in infants and young children with recurrent wheezing. Eighty-five infants or young children with recurrent wheezing, and no gastrointestinal symptoms, underwent 24 hr esophageal pH monitoring, as well as total serum IgE and specific IgE testing for eggs and milk. Among the 85 subjects, 48.2% had significant GER. There was no significant difference in the GER between atopic and non-atopic recurrent wheezers (41.7% and 50.8%, respectively). The sensitization rate to food (eggs or milk) was 12.2% and 20.5% in the GER and non-GER groups, respectively and showed no statistically significant difference between the two groups (P=0.34). In conclusion, about half of infants and young children with recurrent wheezing and no gastrointestinal symptoms have silent GER. The silent GER may not contribute to food sensitization in infants and young children with recurrent wheezing.
    Journal of Korean medical science 03/2010; 25(3):425-8. DOI:10.3346/jkms.2010.25.3.425 · 1.25 Impact Factor
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    ABSTRACT: We present in this article the effect of alternating electric field at kilohertz (kHz) and megahertz (MHz) frequencies on the biological cells in presence and absence of nanoparticles. The induced electric field strength distribution in the region around cell membrane and nucleus envelope display different behavior at kHz and MHz frequencies. The attachment of gold nanoparticles (GNPs), especially gold nanowires around the surface of nucleus induce enhanced electric field strengths. The induced field strengths are dependent on the length of nanowire and create varying field regions when the length of nanowire is increased from 2 to 4 mum. The varying nanowire length increased the induced field strengths inside nucleoplasm and region adjacent to the nucleus in the cytoplasm. We investigated a process of electrostatic disruption of nucleus membrane when the induced electric field strength across the nucleus exceeds its tensile strength.
    Japanese Journal of Applied Physics 08/2009; 48(8). DOI:10.1143/JJAP.48.087001 · 1.06 Impact Factor
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    ABSTRACT: We report a case of acute severe hepatitis with Mycoplasma pneumoniae (M. pneumoniae) infection and transient depression of multiple coagulation factors. A 5-year-old boy, previously healthy, was admitted with pneumonia. M. pneumoniae infection was confirmed by serology testing. Liver enzymes were elevated on admission without any past medical history. After treatment with azithromycin for 3 days, pneumonia improved, but the hepatitis was acutely aggravated. Partial thromboplastin time (PTT) was prolonged and depression of multiple coagulation factors developed. Liver biopsy revealed features consistent with acute hepatitis. A week later, liver enzymes were nearly normalized spontaneously. Normalization of prolonged PTT and coagulation factors were also observed several months later. This may be the first case of transient depression of multiple coagulation factors associated with M. pneumoniae infection.
    Yonsei Medical Journal 01/2009; 49(6):1055-9. DOI:10.3349/ymj.2008.49.6.1055 · 1.26 Impact Factor
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    ABSTRACT: Although it is a rare condition, breast-feeding may result in hypernatremic dehydration. However, incidences might be increasing with more mothers breast-feeding. Although the early detection and management of hypernatremic dehydration from breast-feeding is important, its prevention is even more important on account of its serious complications. In order to prevent hypernatremic dehydration secondary to breast-feeding, it is essential to educate mothers in successful breast-feeding methods. An early follow-up after discharge is recommended. We report a case of hypernatremic dehydration secondary to breast-feeding in a full-term newborn that was corrected without any complications.
    Korean Journal of Pediatrics 01/2007; 50(1):85. DOI:10.3345/kjp.2007.50.1.85
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    ABSTRACT: The prevalence of rickets in the world is on the rise not only in developing but also in developed countries. In Korea, breastfeeding has increased. There have been few studies on the possible association of rickets with breastfeeding. The purpose of this study was to identify the development and the clinical presentation of subclinical rickets in breastfed infants.
    Korean Journal of Pediatrics 01/2007; 50(12). DOI:10.3345/kjp.2007.50.12.1188
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    ABSTRACT: The objective was to investigate the role of Helicobacter pylori infection in iron-deficiency anemia (IDA) of pubescent athletes. Blood sampling and a questionnaire survey were performed on 440 regular high school students and 220 athletes of a physical education high school. Hemoglobin, serum iron, total iron-binding capacity, ferritin, and immunoglobulin G antibody to H. pylori were measured to compare the prevalence of IDA and H. pylori infection in the groups. Nutritional analysis and a questionnaire survey for socioeconomic status were undertaken to compare and control for other risk factors that might influence IDA and H. pylori infection in the groups. In those with IDA coexistent with H. pylori infection, we also determined whether IDA can be managed by H pylori eradication. The prevalence rates of IDA, H pylori infection, and H. pylori -associated IDA in female athletes were higher than in the control group. The relative risk of IDA was 2.9 (95% CI, 1.5 to 5.6) for those with H. pylori infection. Athletes who exhibited H. pylori -associated IDA showed significant increases in hemoglobin, iron, and ferritin levels after H. pylori eradication. The subjects in the control group who were treated orally with iron alone showed no significant changes. Adolescent female athletes may have development of H. pylori -associated IDA, which can be managed by H. pylori eradication.
    Journal of Pediatrics 08/2001; 139(1):100-4. DOI:10.1067/mpd.2001.114700 · 3.74 Impact Factor

Publication Stats

135 Citations
28.49 Total Impact Points

Institutions

  • 2009–2014
    • Pohang University of Science and Technology
      • Department of Electronic and Electrical Engineering
      Geijitsu, Gyeongsangbuk-do, South Korea
  • 2012
    • Colorado State University
      • Department of Electrical & Computer Engineering
      Fort Collins, Colorado, United States
  • 2009–2010
    • Inha University
      • • College of Medicine
      • • Department of Pediatrics
      Chemulpo, Incheon, South Korea