• Progress in Medical Physics
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• v.30 no.4
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• pp.128-138
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• 2019

Purpose: Segmental analysis of volumetric modulated arc therapy (VMAT) is not clinically used for compositional error source evaluation. Instead, dose verification is routinely used for plan-specific quality assurance (QA). While this approach identifies the resultant error, it does not specify which machine parameter was responsible for the error. In this research study, we adopted an approach for the segmental analysis of VMAT as a part of machine QA of linear accelerator (LINAC). Methods: Two portal dose QA plans were generated for VMAT QA: a) for full arc and b) for the arc, which was segmented in 12 subsegments. We investigated the multileaf collimator (MLC) position and dosimetric accuracy in the full and segmented arc delivery schemes. A MATLAB program was used to calculate the MLC position error from the data in the dynalog file. The Gamma passing rate (GPR) and the measured to planned dose difference (DD) in each pixel of the electronic portal imaging device was the measurement for dosimetric accuracy. The eclipse treatment planning system and a MATLAB program were used to calculate the dosimetric accuracy. Results: The maximum root-mean-square error of the MLC positions were <1 mm. The GPR was within the range of 98%-99.7% and was similar in both types of VMAT delivery. In general, the DD was <5 calibration units in both full arcs. A similar DD distribution was found for continuous arc and segmented arcs sums. Exceedingly high DD were not observed in any of the arc segment delivery schemes. The LINAC performance was acceptable regarding the execution of the VMAT QA plan. Conclusions: The segmental analysis proposed in this study is expected to be useful for the prediction of the delivery of the VMAT in relation to the gantry angle. We thus recommend the use of segmental analysis of VMAT as part of the regular QA.

• Journal of Ecology and Environment
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• v.44 no.2
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• pp.106-114
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• 2020

Background: Determining patterns of habitat use is key to understanding of animal ecology. Approximately 1% of bird species use brood parasitism for their breeding strategy, in which they exploit other species' (hosts) parental care by laying eggs in their nests. Brood parasitism may complicate the habitat requirement of brood parasites because they need habitats that support both their host and their own conditions for breeding. Brood parasitism, through changes in reproductive roles of sex or individual, may further diversify habitat use patterns among individuals. However, patterns of habitat use in avian brood parasites have rarely been characterized. In this study, we categorized the habitat preference of a population of brood parasitic lesser cuckoos (Cuculus poliocephalus) breeding on Jeju Island, Korea. By using compositional analyses together with radio-tracking and land cover data, we determined patterns of habitat use and their sexual and diurnal differences. Results: We found that the lesser cuckoo had a relatively large home range and its overall habitat composition (the second-order selection) was similar to those of the study area; open areas such as the field and grassland habitats accounted for 80% of the home range. Nonetheless, their habitat, comprised of 2.54 different habitats per hectare, could be characterized as a mosaic. We also found sexual differences in habitat composition and selection in the core-use area of home ranges (third-order selection). In particular, the forest habitat was preferentially utilized by females, while underutilized by males. However, there was no diurnal change in the pattern of habitat use. Both sexes preferred field habitats at the second-order selection. At the third-order selection, males preferred field habitats followed by grasslands and females preferred grasslands followed by forest habitats. Conclusions: We suggest that the field and grassland habitats represent the two most important areas for the lesser cuckoo on Jeju Island. Nevertheless, this study shows that habitat preference may differ between sexes, likely due to differences in sex roles, sex-based energy demands, and potential sexual conflict.

• Journal of Microbiology and Biotechnology
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• v.28 no.10
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• pp.1626-1634
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• 2018

Ginseng (the root of Panax ginseng Meyer) fermented by Lactobacillus plantarum has been found to attenuate allergic responses in in vitro and in vivo experimental models. Ginseng has been reported to also possess various biological functions including anti-inflammatory activity. The present study was aimed at comparing the anti-allergic effect of ginseng and fermented ginseng extracts on IgE-mediated passive cutaneous anaphylaxis in vitro in a murine cell line and in vivo in mice. Fermented ginseng extract (FPG) showed higher inhibitory effect against in vitro and in vivo allergic responses when compared with ginseng extract (PG). The secretion of ${\beta}$-hexosaminidase and interleukin (IL)-4 from the IgE-DNP-stimulated RBH-2H3 mast cells were significantly (p < 0.05) inhibited by FPG treatment, and this effect was concentration-dependent. Further, MKK4 activation and subsequent JNK phosphorylation were attenuated by FPG treatment. The inhibitory effect of FPG on the in vitro allergic response was verified in vivo against IgE-DNP-induced passive cutaneous anaphylaxis in a mouse model. These data indicated that the fermentation of ginseng with L. plantarum enhanced its anti-allergic effects both in vitro and in vivo. We predict that compositional changes in the ginsenosides caused by the fermentation may contribute to the change in the anti-allergic effects of ginseng. The results of our study highlight the potential of the use of FPG as a potential anti-allergic agent.

• Journal of Korean Society on Water Environment
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• v.33 no.6
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• pp.754-768
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• 2017

Polybrominated diphenyl ethers (PBDEs) are a group of industrial aromatic organobromine chemicals that have been used since the 1970s as flame retardants in a wide range of consumer products and articles, including plastics, computers, textiles and upholstery. Commercial PBDEs were added to Annex A of the Stockholm Convention as persistent organic pollutants in May 2009. PBDEs are still frequently found in sludge and effluent from wastewater treatment plants, even though commercial PBDEs were prohibited or voluntarily phased out several years ago. Conventional wastewater treatment processes are not designed to effectively remove PBDEs. This indicates that there is an urgent need for new developments and improvements to enhance upon the treatment techniques which are currently available. Several studies have suggested the potential removal and degradation technologies for PBDEs in wastewater. In this study, the concentrations and compositional profiles of PBDE congeners in sludge and effluent are investigated by analyzing the relevant literature data in relation to their usage patterns in commercial products in North America and South Korea. The strengths and weaknesses of the current PBDEs removal techniques (i.e., biodegradation, zero-valent iron, photolysis, sorption, etc.) are discussed critically. In addition, future research direction regarding the treatment and removal of PBDEs from wastewater is also suggested, based on the literature review.

• Journal of Applied Biological Chemistry
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• v.62 no.4
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• pp.315-322
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• 2019

Seasonal ginsenoside flux in the leaves of 5-year-old Panax ginseng was analyzed from the field-grown ginseng, for the first time, to study possible biosynthesis and translocation of ginsenosides. The concentrations of nine major ginsenosides, Rg1, Re, Rh1, Rg2, R-Rh1, Rb1, Rc, Rb2, and Rd, were determined by UHPLC during the growth in between April and November. It was confirmed total ginsenoside content in the dried ginseng leaves was much higher than the roots by several folds whereas the composition of ginsenosides was different from the roots. The ginsenoside flux was affected by ginseng growth. It quickly increased to 10.99±0.15 (dry wt%) in April and dropped to 6.41±0.14% in May. Then, it slowly increased to 9.71±0.14% in August and maintained until October. Ginsenoside Re was most abundant in the leaf of P. ginseng, followed by Rd and Rg1. Ginsenosides Rf and Ro were not detected from the leaf. When compared to the previously reported root data, ginsenosides in the leaf appeared to be translocated to the root, especially in the early vegetative stage even though the metabolite translocated cannot be specified. The flux of ginsenoside R-Rh1 was similar to the other (20S)-PPT ginsenosides. When the compositional changes of each ginsenoside in the leaf was analyzed, complementary relationship was observed from ginsenoside Rg1 and Re, as well as from ginsenoside Rd and Rb1+Rc. Accordingly, ginsenoside Re in the leaf was proposed to be synthesized from ginsenoside Rg1. Similarly, ginsenosides Rb1 and Rc were proposed to be synthesized from Rd.

• Journal of the Korean Ceramic Society
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• v.32 no.12
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• pp.1392-1400
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• 1995

WC-10wt%Co-Al2O3 ceramic composites, using both the SHS (Self-propagating High Temperature Synthesis) synthesized WC powder method and commercial WC powder, were prepared by varing WC-Co/Al2O3 vol% ratio and sintering temperature (1350℃∼1650℃) for 1 hr in Ar atmosphere. Mechanical characterization has been investigated by Instron meterial testing system and Vicker's hardness test. Compositional and structural chracterizations were carried out by energy-dispersive analysis of X-ray (EDAX) data and scanning electron microscope (SEM). Electrical characterization was carried out by the electrical resistivity measurement using 4-point probe method. As sintering period increased and Al2O3 contents decreased in WC-10wt%Co-Al2O3 ceramic composite, shrinkage and relative density increased, resulting in maximum values at 1600℃. Also the major matrix phase changed with increasing Al2O3 content from 0 to 100 vol%. It was also identified by SEM, EDAX, and electrical resistivity measurement. Based on the results of analysis of flexural strength, toughness and hardness, the mechanical properties of WC-10wt%Co-Al2O3 ceramic composites using the SHS synthesized WC powder were better than those WC-10wt%Co-Al2O3 ceramic composites using commercial WC powder because WC-10wt%Co-Al2O3 ceramic composites using the SHS synthesized WC powder were sintered very well due to small initial particle size. By the addition of 40 vol% Al2O3 [60(WC=10wt%Co)-40Al2O3], it was possible to obtain a proper candidate as a superalloy.

• Smart Media Journal
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• v.3 no.2
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• pp.20-28
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• 2014

The issues of generation, delivery, and processing of information which have been treated importantly in information design field have evolved along with the evolution of the humankind. In the modern society, the vast amount of, complex, and artificial forms of information such as big-data is accounted for the majority and claims of interest focusing on how to effectively design those kinds of information are being increased. This study explored the visualization methods applied with the natural objects as motives as one of the ways for users to easily get their perception and cognition to the information. Nature has long influenced on the human figural activities. The natural objects take the optimum visual shapes and provide the diverse inspiration and emotion to the designers in the various design fields such as product design, architecture design, and so on. Through the literature studies, we suggested the compositional principles of natural objects and the principles for observing and analysing natural objects as a principle to use the natural objects for information design domain. We, also, suggested the information design approach model which is inspired the natural objects by linking those two kinds of principles to the information design's visual realization factors and explored the possibilities of utilizing of the approach model by the case studies.

• Journal of the Korean Institute of Gas
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• v.9 no.2 s.27
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• pp.50-55
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• 2005

The compositional and structural properties of alkali metal ion exchanged Y-zeolites have been investigated by la number of analytical techniques and their catalytic activities were tested for NOx reduction in combination with a non-thermal plasma. The NOx conversion data for LiY, NaY, KY and CsY were measured by chemiluminiscent NOx meter in the temperature range of 100 to $350^{\circ}C$. The initial activities of the catalyst at $150^{\circ}C$ increased in the order LiY < KY < NaY < CsY in alkali series. The activity of CsY and NaY were increased and showed maximum at $200^{\circ}C$ and then decreased in the plasma reactor, as the temperature increased. The activity of KY maintained same by $200^{\circ}C$ and then decreased, whereas the activity of LiY decreased with the increasing temperature. The CsY catalyst, which showed the highest activity in alkali metal series, exhibits a NOx conversion efficiency of $80\%$ between $170{\~}220^{\circ}C$.

• Transactions on Electrical and Electronic Materials
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• v.16 no.3
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• pp.130-134
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• 2015

This research proposes the use of a composition modulated (ZrO₂)_x(Al₂O₃)_1-x film as a charge trapping layer for charge trap flash memory; this is possible when the Zr (Al) atomic percent is controlled to form a variable bandgap as identified by the valence band offsets and electron energy loss spectrum measurements. Compared to memory devices with uniform compositional (ZrO₂)_0.1(Al₂O₃)_0.9 or a (ZrO₂)_0.92(Al₂O₃)_0.08 trapping layer, the memory device using the composition modulated (ZrO₂)_x(Al₂O₃)_1-x as the charge trapping layer exhibits a larger memory window (6.0 V) at the gate sweeping voltage of ±8 V, improved data retention, and significantly faster program/erase speed. Improvements of the memory characteristics are attributed to the special energy band alignments resulting from non-uniform distribution of elemental composition. These results indicate that the composition modulated (ZrO₂)_x(Al₂O₃)_1-x film is a promising candidate for future nonvolatile memory device applications.

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.594-599
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• 2003

By using the spectroscopic ellipsometry, we have measured and analyzed the optical characteristics of P $r^3$$^{+}$-doped selenide glasses of Ge-Sb-Se system, a strong candidate material for U band fiber amplifiers. The ellipsometric spectra measured in the transparent wavelengths range of the material were all fitted to a model consisting of ambient/roughness/thin fil $m_strate structures to obtain simultaneously the optical properties such as refractive index, in terms of Sellmeier parameters and film structure of P $r^3$$^{+}$-doped selenide glasses. Repeated measurements on different positions in both polished faces rendered to verify positional dependence of measured spectre-ellipsometric data. Hence, the model made possible the analysis of the optical characteristics of the glasses. Even though surface roughness was mainly responsible for the position dependencies, the averaged refractive indexes were as precise as to reflect the minute compositional change tantamount to 1 mol%. The measured refractive indexes are useful for design of core and clad compositions of single-mode selenide optical fibers.