• Journal of Microbiology and Biotechnology
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• v.19 no.5
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• pp.502-510
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• 2009

Although the Escherichia coli heat-labile enterotoxin B subunit (LTB) has already been expressed in several different systems, including prokaryotic and eukaryotic organisms, studies regarding the synthesis of LTB into oligomeric structures of pentameric size in the budding yeast Saccharomyces cerevisiae have been limited. Therefore, this study used a functional signal peptide of the amylase 1A protein from rice to direct the yeast-expressed LTB towards the endoplasmci reticulum to oligomerize with the expected pentameric size. The expression and assembly of the recombinant LTB were confirmed in both the cell-free extract and culture media of the recombinant strain using a Western blot analysis. The binding of the LTB pentamers to intestinal epithelial cell membrane glycolipid receptors was further verified using a GM1-ganglioside enzyme-linked inmmunosorbent assay (GM1-ELISA). On the basis of the GM1-ELISA results, pentameric LTB proteins comprised approximately 0.5-2.0% of the total soluble proteins, and the maximum quantity of secreted LTB was estimated to be 3 mg/l after a 3-day cultivation period. Consequently, the synthesis of LTB monomers and their assembly into biologically active aligomers in a recombinant S. cerevisiae strain demonstrated the feasibility of using a GRAS microorganism-based adjuvant, as well as the development of carriers against mucosal disease.

• Journal of Powder Materials
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• v.15 no.1
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• pp.6-12
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• 2008

[ $YBa_2Cu_3O_{7-y}$ ](123) powders were synthesized by the solid state reaction method using two different purity $BaCO_3$ powders (99.75% and 99.7% purity) and $Y_2O_3$ (99.9%) and CuO (99.9%) powders. The effect of $BaCO_3$ purity on the formation of a 123 phase and the superconducting properties were investigated. The mixtures of raw powders were calcined at temperature ranges of $800^{\circ}C-880^{\circ}C$ in air and finally made into a single grain samples by a melt processing with top seeding. It was found that a 123 phase was well formed at temperature above $870^{\circ}C$, but the purity effect on the 123 formation was negligible. The single-grain 123 samples prepared from the different $BaCO_3$ powders showed the same $T_c$ value of 90.5 K and similar $J_c$ values about $10^4\;A/cm^2$ at 0 T and 77 K, and $10^3\;A/cm^2$ at 2 T and 77 K. This result indicates that the low purity, cheap price $BaCO_3$ powder can be used as a raw material for the fabrication of single-grain, high-$J_c$ superconducting levitator.

• Applied Biological Chemistry
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• v.48 no.4
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• pp.388-393
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• 2005

This study was conducted to experiment the removal efficiency of 6 pesticides in fruits and vegetables using various washing solutions. As results, the average removal efficiencies of pesticides washed with tap-water were 68.3%, whereas those washed by ultrasonic cleaning for 2 and 5 minutes were 73.7% and 82.5%, respectively. Using different washing solutions with various additional materials such as 0.5% detergent, 5% vinegar, 5% salt and flour, the removal rates were 82.9%, 76.9%, 75.8% and 75.7%, respectively. With 0.5% detergent, pesticides were 20% more removed when washed by ultrasonic cleaning than tap-water washing; moreover, Chlorthalonil in cherry tomato showed the highest removal efficiency while EPN in grape washed with tap-water showed the lowest. The order of removal efficiencies of pesticides were Chlorthalonil (90.0%)>Procymidone (81.3%)>Chlorpyrifos (76.6 %)>Endosulfan (75.7%)>Fenitrothion (75.5%)>EPN (73.8%).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.626-631
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• 2018

An emergency evacuation support system is used to maintain evacuation routes by pressurizing a space inside screens. In cases of fire, it is important to understand the thermal distributions in the tunnel for preventing system failure. In this study, we numerically investigated the effect of fire on an emergency evacuation support system in a large fabric store with some fire scenarios with different combustibles. The critical temperature for system failures was assumed to be $200^{\circ}C$. As a result, the highest temperature was predicted in the ceiling part due to the effect of a ceiling jet, and the fire safety of the screen was secured at distances of 20 to 30 m according to the heat release rate. To prevent the inflow of smoke into the system, it is necessary to maintain more than 5 Pa if positive pressure inside the smoke screen. The results of this study could be useful for designing an emergency evacuation support system.

• Clinical and Experimental Pediatrics
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• v.45 no.3
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• pp.413-417
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• 2002

Gitelman's syndrome is an autosomal recessive disorder characterized by hypokalemic metabolic alkalosis, hypomagnesemia, and hypocalciuria that has recently been reported to be linked to thiazide- sensitive Na-Cl cotransporter gene mutation. In this study, we performed renal clearance studies to differentiate Gitelman's from Bartter's syndrome and to confirm the diagnosis in two patients clinically diagnosed with Gitelman's syndrome. Each patient was hydrated by 20 mL/kg body weight of oral water within 30 minutes, which was followed by intravenous half saline. When urinary flow reached 10 mL/min, samples of urine and serum were obtained to calculate the osmolar clearance, free water clearance, chloride clearance, and distal fractional chloride reabsorption. Subsequently, furosemide or hydrochlorothiazide was administered. Samples were collected and the same parameters were calculated. In our patients, chloride clearance was increased more than 10 times after furosemide administration(2.1 : 25.7 and 2.2 : 27.4 mL/min/100 mL GFR), but not increased after hydrochlorothiazide treatment(2.1 : 1.6 and 2.2 : 2.6 mL/min/100 mL GFR). And the distal fractional chloride reabsorption was significantly decreased by furosemide injection (73% : 15% and 75% : 4.6%), whereas hydrochlorothiazide had no effect on it(73% : 63% and 75% : 78%). These findings indicate that our patients have a defect in thiazide-sensitive Na-Cl cotransporter in the distal tubule, which is compatible with the pathophysiology of Gitelman's syndrome.

• Radiation Oncology Journal
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• v.29 no.3
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• pp.206-213
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• 2011

Purpose: Intensity modulated radiation therapy (IMRT) is a high precision therapy technique that can achieve a conformal dose distribution on a given target. However, organ motion induced by respiration can result in significant dosimetric error. Therefore, this study explores the dosimetric error that result from various patterns of respiration. Materials and Methods: Experiments were designed to deliver a treatment plan made for a real patient to an in-house developed motion phantom. The motion pattern; the amplitude and period as well as inhale-exhale period, could be controlled by in-house developed software. Dose distribution was measured using EDR2 film and analysis was performed by RIT113 software. Three respiratory patterns were generated for the purpose of this study; first the 'even inhale-exhale pattern', second the slightly long exhale pattern (0.35 seconds longer than inhale period) named 'general signal pattern', and third a 'long exhale pattern' (0.7 seconds longer than inhale period). One dimensional dose profile comparisons and gamma index analysis on 2 dimensions were performed. Results: In one-dimensional dose profile comparisons, 5% in the target and 30% dose difference at the boundary were observed in the long exhale pattern. The center of high dose region in the profile was shifted 1 mm to inhale (caudal) direction for the 'even inhale-exhale pattern', 2 mm and 5 mm shifts to exhale (cranial) direction were observed for 'slightly long exhale pattern' and 'long exhale pattern', respectively. The areas of gamma index >1 were 11.88 %, 15.11%, and 24.33% for 'even inhale-exhale pattern', 'general pattern', and 'long exhale pattern', respectively. The long exhale pattern showed largest errors. Conclusion: To reduce the dosimetric error due to respiratory motions, controlling patient's breathing to be closer to even inhaleexhale period is helpful with minimizing the motion amplitude.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.44-44
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• 2018

경상북도 봉화군에 위치한 각화산(1,177m)은 태백산맥에서 소백산맥으로 갈라지는 기점을 이루는 산으로 구령산, 청옥산, 옥석산 등과 함께 백두대간 일대의 중요한 산으로 인식된다. 특히 각화산은 조선왕조실록을 보관했던 태백산 사고지터(사적 제 348호)를 품고 있는 역사적인 장소이기도 하다. 본 연구는 각화산 일대 관속식물의 분포상을 파악하고자 2017년 5월부터 2018년 9월까지 진행되었다. 연구 결과 조사지 내 관속식물은 92과 291속 413종 4아종 38변종 6품종으로 총 461분류군이 확인되었다. 이는 경상북도 관속식물 1,684분류군(Korea National Arboretum, 2016)의 27.4%, 한반도 관속식물 4,499분류군(Korea National Arboretum, 2018; Http://www.nature.go.kr/kpni/)의 10.2%에 해당되는 것으로 분석되었다. 각화산 일대의 주요 식물 가운데 한국특산식물은 12분류군(할미밀망, 진범, 처녀치마, 지리대사초 등)이 확인되었고, 산림청 지정 희귀식물은 VU등급(꼬리진달래, 노랑무늬붓꽃) 2분류군, LC등급(너도바람꽃, 쥐방울덩굴, 도깨비부채) 3분류군으로 총 5분류군의 희귀식물이 분포하는 것으로 조사되었다. 또한, 식물구계학적 특정식물 IV등급 5분류군, III등급 13분류군, II등급 21분류군, I 등급 25분류군이 확인되었고, 외래식물은 총 24분류군으로 도시화지수(%) 6.8%, 귀화율은 5.2%에 해당되는 것으로 분석되었다. 조사된 식물의 유용성 분석 결과, 식용식물 348분류군(75.5%), 섬유용식물 1분류군(0.2%), 약용식물 기분류군(15.4%), 관상용식물 18분류군(3.9%), 목초용식물 102분류군(22.1%) 목재용식물 14분류군(3.0%) 등으로 확인되었다. 본 연구 결과물은 각화산의 식물 현황을 제시함과 동시에 생태축으로 연결된 백두대간 일대의 효율적인 관리 및 보전 방안을 마련하기 위한 기초자료로 활용 될 것이라 기대한다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.45-45
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• 2018

경상북도 봉화군에 위치한 갈방산(712m)은 백두대간 옥석산(1,244m)에서 분기한 문수지맥의 산지 가운데 하나다. 본 연구는 갈방산 일대 관속식물의 분포상을 파악하고자 2017년 5월부터 2018년 9월까지 진행되었다. 연구 결과 92과 265속 373종 4아종 44변종 5품종으로 총 426분류군의 관속식물이 조사지에서 확인되었다. 이는 경상북도 관속식물 1,684분류군(Korea National Arboretum, 2016)의 25.3%, 한반도 관속식물 4,499분류군(Korea National Arboretum, 2018; Http://www.nature.go.kr/kpni/)의 9.5%에 해당되는 것으로 분석되었다. 갈방산 일대의 주요 식물 가운데 한국특산식물은 11분류군(키버들, 병꽃나무, 처녀치마 등)이 확인되었고, 산림청 지정 희귀식물은 VU등급(세잎승마) 1분류군, LC등급(도깨비부채, 태백제비꽃) 2분류군으로 총 3분류군의 희귀식물이 분포하는 것으로 조사되었다. 또한, 식물구계학적 특정식물 V등급 1분류군, IV등급 2분류군, III등급 10분류군, II등급 16분류군, I 등급 23분류군이 확인되었고, 외래식물은 총 22분류군으로 도시화지수(%) 6.3%, 귀화율은 5.2%에 해당되는 것으로 분석되었다. 조사된 식물의 유용성 분석 결과, 식용식물 345분류군(81%), 섬유용식물 4분류군(0.9%), 약용식물 85분류군(20.0%), 관상용식물 18분류군(4.2%), 목초용식물 109분류군(25.6%) 목재용식물 15분류군(3.5%) 등으로 확인되었다. 요컨대 갈방산 일대의 식물 현황을 제시함으로써 본 연구 결과물이 갈방산 일대의 희귀특산식물과 유용식물의 보전 및 활용 방안을 마련하기 위한 기초자료로 활용 될 것이라 기대한다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.90-97
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• 2006

We report our research work on the millimeter-wave broadband amplifier integrating the shunt peaking technology with the cascode configuration. The millimeter-wave broadband cascode amplifier on MIMIC technology was designed and fabricated using $0.1{\mu}m\;{\Gamma}-gate$ GaAs PHEMT, CPW, and passive library. The fabricated PHEMT has shown a transconductance of 346.3 mS/mm, a current gain cut off frequency ($f_T$) of 113 GHz, and a maximum oscillation frequency ($f_{max}$) of 180 GHz. To prevent oscillation of designed cascode amplifier, a parallel resistor and capacitor were connected to drain of common-gate device. For expansion of the bandwidth and flatness of the gain, we inserted the short stub into bias circuits and the compensation transmission line between common-source device and common-gate device, and then their lengths were optimized. Also, the input and output stages were designed using the matching method to obtain the broadband characteristic. From the measurement, we could confirm to extend bandwidth and flat gain by integrating the shunt peaking technology with the cascode configuration. The cascode amplifier shows the broadband characteristic from 19 GHz to 53.5 GHz. Also, the average gain of this amplifier is about 6.5 dB over the bandwidth.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.835-842
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• 2009

DVB-SSP is a new broadcasting system for hybrid satellite communications, which supports mobile handheld systems and fixed terrestrial systems. However, a critical factor must be considered in upper layer decoding which including erasure Reed-Solomon error correction combined with cyclic redundancy check. If there is only one bit error in an IP packet, the entire IP packet is considered as unreliable bytes, even if it contains correct bytes. IF, for example, there is one real byte error, in an If packet of 512 bytes, 511 correct bytes are erased from the frame. Therefore, this paper proposed two kinds of upper layer decoding methods; LLR-based decoding and hybrid decoding. By means of simulation we show that the performance of the proposed decoding algorithm is superior to that of the conventional one.