• Tuberculosis and Respiratory Diseases
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• v.85 no.1
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• pp.25-36
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• 2022

Background: Only a few studies directly compared the therapeutic efficacy and safety of two pressurized metered-dose inhalers (pMDIs) in asthma. We analyzed the asthma treatment outcomes, safety, and patient preferences using formoterol/beclomethasone (FORM/BDP), a pMDI with extra-fine particles, compared with formoterol/budesonide (FORM/BUD), another pMDI with non-extra-fine particles. Methods: In this randomized, double-blind, double-dummy parallel group study, 40 adult asthmatics were randomized to FORM/BDP group (n=18; active FORM/BDP and placebo FORM/BUD) or FORM/BUD group (n=22; active FORM/BUD and placebo FORM/BDP). During the two visits (baseline and end of 8-week treatment), subjects were asked to answer questionnaires including asthma control test (ACT), asthma control questionnaires (ACQ), and Quality of Life Questionnaire for Adult Korean Asthmatics (QLQAKA). Lung function, compliance with inhaler, and inhaler-handling skills were also assessed. Results: Ten subjects in the FORM/BDP group and 14 in the FORM/BUD group completed follow-up visits. ACT, ACQ, QLQAKA (a primary outcome), and adverse events did not differ between two groups. We found that the increase in forced expiratory volume in 1 second/forced vital capacity and forced expiratory flow at 25% to 75% of the pulmonary volume in the FORM/BDP group was higher than in the FORM/BUD group. Regarding preference, subjects responded that the flume velocity of FORM/BDP was higher, but more adequate than that of FORM/BUD. They also answered that FORM/BDP reached the trachea and bronchus and irritated them significantly more than FORM/BUD. Conclusion: The use of pMDI with extra-fine particles may relieve small airway obstruction more than the one with non-extra-fine particles despite no significant differences in overall treatment outcomes. Some asthmatics have a misconception about the adequacy of high flume velocity of pMDIs.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.2
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• pp.91-97
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• 2018

High-energy charged particles are comprised of galactic cosmic rays and solar energetic particles which are mainly originated from the supernova explosion, active galactic nuclei, and the Sun. These primary charged particles which have sufficient energy to penetrate the Earth's magnetic field collide with the Earth's upper atmosphere, that is $N_2$ and $O_2$, and create secondary particles and ionizing radiation. The ionizing radiation can be measured at commercial flight altitude. So it is recommended to manage radiation dose of aircrew as workers under radiation environment to protect their health and safety. However, it is hard to deploy radiation measurement instrument to commercial aircrafts and monitor radiation dose continuously. So the numerical model calculation is performed to assess radiation exposure at flight altitude. In this paper, we present comparison result between measurement data recorded on several flights and estimation data calculated using model and examine the characteristics of the radiation environment in the atmosphere.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.7
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• pp.328-334
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• 2002

The DNA chips are devices associating the specific recognition properties of two DNA single strands through hybridization process with the performances of the microtechnology. In the literature, the "Gene chip" or "DNA chip" terminology is employed in a wide way and includes macroarrays and microarrays. Standard definitions are not yet clearly exposed. Generally, the difference between macro and microarray concerns the number of active areas and their size, Macroarrays correspond to devices containing some tens spots of 500$\mu$m or larger in diameter. microarrays concern devices containing thousnads spots of size less than 500$\mu$m. The key technical parameters for evaluating microarray-manufacturing technologies include microarray density and design, biochemical composition and versatility, repreducibility, throughput, quality, cost and ease of prototyping. Here we report, a new method in which minute particles are arranged in a random fashion on a chip pattern using random fluidic self-assembly (RFSA) method by hydrophobic interaction. We intend to improve the stability of the particles at the time of arrangement by establishing a wall on the chip pattern, besides distinction of an individual particle is enabled by giving a tag structure. This study demonstrates the fabrication of a chip pattern, immobilization of DNA to the particles and arrangement of the minute particle groups on the chip pattern by hydrophobic interaction.ophobic interaction.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.29-29
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• 2014

A fundamental problem in space physics is to explain the origin of energetic charged particles in space close to the Earth and the significant temporal variations of their flux. The particles are primarily electrons and protons although energetic heavy ions such as O+ are sometimes non-negligible. By "energetic" we mean a rather broad energy range of particles from a few tens of keV to well above MeV. Drastic variations of the particle fluxes (by >3 orders of magnitude) occur over both a short time scale like a few minutes and a long time scale like the 11-year sunspot cycle. In this talk I will focus on relativistic energy electrons (~MeV) trapped within the Earth's magnetosphere. They are a primary element of the space weather since they can cause damage to satellites, so often called "killer electrons". Considering that the source particles in both the solar wind and the ionosphere are relatively cold (~eV), the quasi-permanent existence of these very energetic particles close to the Earth has been a surprise to space physicists for decades. Complex electromagnetic processes such as wave-particle interactions within the magnetosphere are believed to play a major role in generating these killer electrons. While detailed physics remains an active research area, for this lecture I will introduce a synthesized picture of how solar activities are related to wave-particle interaction physics inside the magnetosphere. This can be applied to other astrophysical systems.

• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1141-1146
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• 2012

Ce-doped $Y_3Al_5O_{12}$ (YAG:Ce) phosphor powder was prepared using a ${NO_3}^-$-malonic acid-$NH_4NO_3-NH_3{\cdot}H_2O$ system. The YAG:Ce precursor was ignited at $240^{\circ}C$ and the resulting powder contained YAG:Ce crystallites (42%) - active in the visible region at 460 nm - amorphous particles (53%) - inactive at visible wavelengths - and less than 3% oxide (3%) crystallite impurities. The impurities transformed to acitive YAG:Ce crystallites at above $800^{\circ}C$. At above $1000^{\circ}C$, the amorphous phase became YAG phase and isolated $Ce_2O$ crystallites emerged. The powder particles comprised < $4{\mu}m$ secondary aggregates of 20 nm primary particles. The thermal dusting of the secondary particles coincided with the aggregation of the secondary particles at above $900^{\circ}C$.

• Biomolecules & Therapeutics
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• v.20 no.1
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• pp.75-80
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• 2012

The aim of this study was to explore the role and effect of ginsenosides Rg1 on osteoblasts cultured with Ti particles. Osteoblasts from neonatal rats were cultured with particles and different doses of Rg1, the main active ingredient in ginsenosides Rg1. We found that the COX-2, $PGE_2$, TNF-${\alpha}$, IL-1, and IL -6 concentrations in the medium of cells cultured with Ti particles significantly increased as compared with that of the control cells (p<0.05 or p<0.01). In addition, cells cultured with Ti particles alone exhibited the highest concentrations of these molecules. The $PGE_2$, TNF-${\alpha}$, IL-1, and IL-6 levels in the medium of cells cultured with Rg1 were in between those of the control cells and the cells cultured with Ti particles alone. The IL-1ra level in the group cultured with Ti and medium-dose Rg1 was the highest followed by the cells cultured with Ti and high-dose Rg1 and those cultured with Ti and low-dose Rg1 (p<0.05). In conclusion, ginsenosides can reduce the levels of infl ammatory cytokines produced by osteoblasts on induction with Ti particles and can prevent prosthesis loosening.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.87.1-87.1
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• 2010

Main-belt comets (hereafter MBCs) are one of the hottest topics in the solar system astronomy. They are objects orbiting in the main asteroid belt which show cometary activity. Unlike most comets, which spend most of their orbit beyond 5AU from the Sun, MBCs follow near-circular orbits within the asteroid belt that are indistinguishable from the orbits of major population of the asteroids. P/2010 A2, the fifth MBC, was discovered by on January 6, 2010 by Lincoln Near-Earth Asteroid Research. It passed its perihelion at 2.01AU on December 3, 2009, about a month before it was discovered. With an aphelion of only 2.6 AU, P/2010 A2 spends all of its time inside of the frostline ~2.7 AU. We made observations of P/2010 A2 with Nishi-Harima Astronomical Observatory 2-m telescope only a week after the discovery. From the observed images, we found that the dust cloud was composed of large particles (>1mm) impulsively ejected between March and June, 2009. No coma was detected by our observations, suggesting that this object was no longer active. Consequently, we conjecture that these dust particles could be released by the impact collision among asteroids.

• Journal of Powder Materials
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• v.6 no.4
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• pp.320-324
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• 1999

The formation, microstructure and properties of novel ceramic composite materials manufactured by active-filler-controlled polymer pyrolysis were investigated. In the presence of active filler particles such as transition metals, bulk components of various geometry could be fabricated from siliconorganic polymer. Molybdenum- and tungsten-filled polymer suspensions were prepared and their conversion to ceramic composites by annealing in $CH_4$ atmosphere were studied. Dimensional change. porosity and phase distribution (filler network) were analyzed and correlated to the resulting hardness values. Molybdenum and tungsten as active filler were carburized completely to $Mo_2C$, $W_2C$ and WC in $CH_4$ atmosphere. Consequently, microcrystalline composites with the filler reaction products embedded in a silicon oxycarbide glass matrix were formed. Hardness was increased with increasing carburization and reached 8.6-9.5 GPa in the specimen pyrolyzed in $CH_4$ atmosphere.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.97-97
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• 2003

Chemists must take into consideration more factors to formulate with inorganic sunscreens than many other active ingredients including organic sunscreens. Because the UV radiation attenuation grade particles of Titanium Dioxide and Zinc Oxide are in the nanometer range, the state of their dispersion in the product film on the skin governs their efficacy and aesthetics.(omitted)

• Particle and aerosol research
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• v.4 no.2
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• pp.51-67
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• 2008

In this study, we devoted to kinetic measurement of the catalytic oxidation of iron-containing flame soot particles and better understanding the role of catalytic particles on carbon oxidation in particular at low temperature, targeting on autothermal regeneration of diesel particulate filter by diesel exhaust gas. Carbon-based Fe-containing particles generated by spraying ferrocene-doped diesel fuel in an oxy-hydrogen flame are tested and compared with a commercial carbon black powder for thermogravimetric analysis (TGA), secondary ion mass spectrometry (SIMS), Fourier-transform infrared spectroscopy (FTIR), Induced coupled plasma-Atomic emission spectroscopy (ICP-AES), and High-resolution transmission electron microscopy (HR-TEM). As a result, we found that a small amount of the ferrocene addition led to significant reductions in a on-set temperature and an activation energy of the carbon oxidation as well. An oxygenated surface complex forming at the particle surface could be thought as active species that would be readily consumed in particular at low temperature.