• Korean Journal of Plant Tissue Culture
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• v.25 no.3
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• pp.183-187
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• 1998

Chlorophyll mutants were produced by treating the rhizome of Cymbidium kanran with mutagen, EMS(ethyl methan sulfonate). The germination ratio of Cymbidium kanran seeds was 5.5 times higher when the seeds were treated with ultrasonic treatment for 20 minutes than untreated control. Fifty to sixty percent of the rhizomes became dark brown when they were cultured in a liquid growth medium containing 0.2% EMS for three weeks. When the dark-brown rhizomes were cultured in a solified MS medium, new rhizomes were developed from a part of the old ones. Chlorophyll mutant rhizomes were obtained from a meristem tissue by a subculturing the cuts of these new rhizomes for a year. Of the chlorophyll mutants, a zigzag-striped type of rhizome was dominant and light-yellow and albino ones were also produced. While the zigzag-striped type rhizomes were differentiated into green and striped plant, the light yellow and the white rhizomes produced yellow-striped and albino plants repectively.These results indicate that the EMS treatment on the rhizome is an effective means to induce a chlorophyll mutant. We believe that this method may be useful to produce variegated plants chlorophyll mutants from other orchids.

• Korean Journal of Remote Sensing
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• v.19 no.3
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• pp.223-231
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• 2003

With the negative influences and damage from Asian dust increasing, it's getting important to investigate the climate and soil condition of the source region of Asian dust. There is a high possibility that the desertification and the drastic decrease of plants in China and Mongolia make worse the situation (bad effects of Asian Dust). To detect the movement of Asian dust caused by air circulation, we need to watch the state of the source region to get useful information for the prevention of the dust pollution, and to predict what part of China will become the source region. Therefore, using TOMS aerosol index data, NCEP reanalysis data that is Remote Sensing data from 1981 to 2000 (except 1993~1996, 4 years), for 16 years, examined the relation between the dust occurrence and weather elements. Dust occurrence appeared much in spring season from March to May in study areas. It had a dry climate during that season as follows : relative humidity about 20~40%, temperature about -5~5$^{\circ}C$, precipitation about 33-180 mm, wind speed about 4-10 ms-1. Dust occurrence and weather element annual change in study areas decreased gradually till 1990, but in Gobi desert the incidence of dust occurrence increased since 1997. As a result, found out that the more the precipitation, the less dust occurrence, because the precipitation and surface wind speed had a direct influence on the soil of the source region of dust.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.266-276
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• 2002

A red ginseng acidic polysaccharide(RGAP) with immunomodulating antitumor activities was isolated from Korean red ginseng, The molecular weight of RGAP was estimated to be 12-450 kDa by gel filtration chromatography, RGAP was found to increase survival rate and to inhibit of tumor growth significantly in a dose dependent manner in mice transplanted with tumor cells. RGAP significantly promoted nitric oxide(NO) production from peritoneal macrophages bothin vivo and in vitro. Western blot analysis exhibited a newly synthesized inducible nitric oxide synthase(iNOS) protein band in the RGAP treated group. It seems likely that immunomodulating antitumor activities of RGAP are mainly mediated by NO production of macrophage. RGAP was further purified by ultrafiltration and anion exchange chromatography on DEAE-sepharose, followed by gel filtration on Sephacryl S-300 to give an active fraction(GFP) with stronger NO production in murine macrophages. GFP increased survival rate ten times compared to RGAP in male ICR mice transplanted with sarcoma 180 and also showed more potent tumoricidal activities of natural killer cells than RGAP. Sugar $composition(mol\%)$ of GFP was found to be arabinose:rhamnose:xylose:galacturonic acid:mannose:galactose:glucose(10:9:1:25:8:20:27) by GC/MS. The results suggest that clinical trials of RGAP in immunotherapy against cancer are highly feasible.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3406-3412
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• 2021

A real-time digital time-stamp sorting algorithm used in the In-Beam positron emission tomography (In-Beam PET) is presented. The algorithm is operated in the field programmable gate array (FPGA) and a small amount of registers, MUX and memory cells are used. It is developed for sorting the data of annihilation event from front-end circuits, so as to identify the coincidence events efficiently in a large amount of data. In the In-Beam PET, each annihilation event is detected by the detector array and digitized by the analog to digital converter (ADC) in Data Acquisition Unit (DAQU), with a resolution of 14 bits and sampling rate of 50 MS/s. Test and preliminary operation have been implemented, it can perform a sorting operation under the event count rate up to 1 MHz per channel, and support four channels in total, count rate up to 4 MHz. The performance of this algorithm has been verified by pulse generator and ²²Na radiation source, which can sort the events with chaotic order into chronological order completely. The application of this algorithm provides not only an efficient solution for selection of coincidence events, but also a design of electronic circuit with a small-scale structure.

• Journal of Korea Port Economic Association
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• v.36 no.4
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• pp.107-120
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• 2020

This study analyzed the competitiveness of major export industries following the FTA between Korea and five Central American countries. Findings revealed that Korea mainly exports industrial products such as ships, automobiles and parts, steel, and electronic devices, and it imports raw materials and agricultural products such as coffee and copper, indicating a complementary trade structure. Similarly, the trade specialization index analysis revealed that Korea specialized in exporting industrial products such as ships, automobiles, steel, and machinery, and in importing primary products such as copper and coffee. Products such as ships, steel, and machinery, which are major export items to Central America, are expected to further strengthen their competitiveness due to tariff cuts. In addition, it is expected that the demand for medicines and medical supplies could increase in future due to the COVID-19 pandemic. This study attempted to present implications for establishing export strategies by analyzing the competitiveness of Korea's major export industries in the Central American market, in accordance with the Korean-Central American FTA. These findings could be used as basic data for future entry into South America as a bridgehead in the Central American market.

• Journal of ILASS-Korea
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• v.23 no.4
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• pp.185-191
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• 2018

Benzene, toluene, ethylbenzene and xylene (BTEX) were well known as ozone precursors from photochemical reactions and contribute to the formation of photochemical smog which pose health hazards. Also, some of these compounds directly affect the human health due to their toxicity such as benzene. In this study, BTEX ratios and correlation of $C_2$-benzenes (xylenes, ethylbenzene) in vehicle exhaust from recreational vehicle (RV) and multi-purpose vehicle (MPV) were characterized using a chassis dynamometer. VOCs were collected by tedlar bag and a GC/MS system was used for their quantification. Among all of the BTEX, toluene has the highest concentration(more than 30% in composition of BTEX). The average ratio of toluene to benzene emissions (T/B ratio=2.2) was found in vehicle exhaust. The average m,p-xylene/ethylbenzene and m,p-xylene/o-xylene ratios were 1.0 and 3.0 respectively. As a result, it showed a good correlation between the $C_2$-benzenes ($R^2=0.98{\sim}0.99$). In the future, it can be used as a marker for effect evaluation to atmospheric environment by vehicle exhaust.

• Journal of Microbiology and Biotechnology
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• v.29 no.1
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• pp.79-90
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• 2019

Lichens are generally known as self-sufficient, symbiotic life-forms between fungi and algae/cyanobacteria, and they also provide shelter for a wide range of beneficial bacteria. Currently, bacterial-derived biodegradable polyhydroxyalkanoate (PHA) is grabbing the attention of many researchers as a promising alternative to non-degradable plastics. This study was conducted to develop a new method of PHA production using unexplored lichen-associated bacteria, which can simultaneously degrade two ubiquitous industrial toxins, anthracene and naphthalene. Here, 49 lichen-associated bacteria were isolated and tested for PHA synthesis. During the GC-MS analysis, a potential strain of EL19 was found to be a 3-hydroxyhexanoate (3-HHx) accumulator and identified as Pseudomonas sp. based on the 16S rRNA sequencing. GC analysis revealed that EL19 was capable of accumulating 30.62% and 19.63% of 3-HHx from naphthalene and anthracene, respectively, resulting in significant degradation of 98% and 96% of naphthalene and anthracene, respectively, within seven days. Moreover, the highly expressed phaC gene verified the genetic basis of $PHA_{mcl}$ production under nitrogen starvation conditions. Thus, this study strongly supports the hypothesis that lichen-associated bacteria can detoxify naphthalene and anthracene, store energy for extreme conditions, and probably help the associated lichen to live in extreme conditions. So far, this is the first investigation of lichen-associated bacteria that might utilize harmful toxins as feasible supplements and convert anthracene and naphthalene into eco-friendly 3-HHx. Implementation of the developed method would reduce the production cost of $PHA_{mcl}$ while removing harmful waste products from the environment.

• Microbiology and Biotechnology Letters
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• v.50 no.4
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• pp.522-532
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• 2022

Cheonggukjang is a traditional fermented food in Korea, which is known to exert beneficial effects on health. In this study, we evaluated the effects of cheonggukjang fermented by Bacillus subtilis SCGB 574 (B574) on high fat diet (HFD)-deteriorated large intestinal health. Rats were fed with HFD or HFD supplemented with 10.1% cheonggukjang (B574). Fecal microbiota was analyzed based on 16S rRNA gene sequences, and the fecal and serum metabolome were measured using GC-MS. Our results showed that SCGB574 intake significantly reduced body weight, restored tight junction components, and ameliorated inflammatory cell infiltration. SCGB574 also shifted gut microbiota by increasing the abundance of short chain fatty acid producers such as Alistipes and Flintibacter, although it decreased the abundance of Lactobacillus. Serum and fecal metabolome analyses showed significantly different metabolic profiles between the groups. The top five metabolites increased by SCGB574 were i) arginine biosynthesis, ii) alanine, aspartate, and glutamate metabolism; iii) starch and sucrose metabolism; iv) neomycin, kanamycin, and gentamicin biosynthesis; and v) galactose metabolism. These results showed that cheonggukjang fermented by SCGB574 ameliorates adverse effects of HFD through improving intestinal health.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.3
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• pp.701-720
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• 2023

Aerial objects are more challenging to segment than normal objects, which are usually smaller and have less textural detail. In the process of segmentation, target objects are easily omitted and misdetected, which is problematic. To alleviate these issues, we propose local aggregation feature pyramid networks (LAFPNs) and pyramid integrated context modules (PICMs) for aerial object segmentation. First, using an LAFPN, while strengthening the deep features, the extent to which low-level features interfere with high-level features is reduced, and numerous dense and small aerial targets are prevented from being mistakenly detected as a whole. Second, the PICM uses global information to guide local features, which enhances the network's comprehensive understanding of an entire image and reduces the missed detection of small aerial objects due to insufficient texture information. We evaluate our network with the MS COCO dataset using three categories: airplanes, birds, and kites. Compared with Mask R-CNN, our network achieves performance improvements of 1.7%, 4.9%, and 7.7% in terms of the AP metrics for the three categories. Without pretraining or any postprocessing, the segmentation performance of our network for aerial objects is superior to that of several recent methods based on classic algorithms.

• Journal of Microbiology and Biotechnology
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• v.33 no.11
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• pp.1437-1447
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• 2023

A recently bioinformatic analysis of genomic sequences of fungi indicated that fungi are able to produce more secondary metabolites than expected. Despite their potency, many biosynthetic pathways are silent in the absence of specific culture conditions or chemical cues. To access cryptic metabolism, 108 fungal strains isolated from various sites were cultured with or without Streptomyces sp. 13F051 which mainly produces trichostatin analogues, followed by comparison of metabolic profiles using LC-MS. Among the 108 fungal strains, 14 produced secondary metabolites that were not recognized or were scarcely produced in mono-cultivation. Of these two fungal strains, Myrmecridium schulzeri 15F098 and Scleroconidioma sphagnicola 15S058 produced four new compounds (1-4) along with a known compound (5), demonstrating that all four compounds were produced by physical interaction with Streptomyces sp. 13F051. Bioactivity evaluation indicated that compounds 3-5 impede migration of MDA-MB-231 breast cancer cells.