• Korean Journal of Materials Research
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• v.8 no.6
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• pp.532-537
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• 1998

The purpose of this study was to investigate the behavior of ozone in DI water and the reaction with wafers during the semiconductor wet cleaning process. The solubility of ozone in DI water was not only dependent on the temperature but also directly proportional to the input concentration of ozone. The lower the initial ozone concentration and the temperature, the longer the half-life time of ozone. The reaction order of ozone in DI water was calculated to be around 1.5. The redox potential reached a saturation value in 5min and slightly increased as the input ozone concentrations increased. The completely hydrophilic surface was created in Imin when HF etched silicon wafer was cleaned in ozonized DI water containing higher ozone concentrations than 2ppm. Spectroscopic ellipsometry measurements showed that the chemical oxide formed by ozonized DI water was measured to be thicker than that by piranha solution. The wafers contaminated with a non-ionic surfactant were more effectively cleaned in ozonized DI water than in piranha and ozonized piranha solutions.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.54-54
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• 2018

억새(Miscanthus spp.)는 우리나라 등 동아시아가 원산이며 바이오매스량이 많아 바이오에너지 원료작물로서 잠재성이 크기 때문에 2세대 바이오에탄올 생산 원료로 주목을 받고 있고, 축산깔개 및 토양개량제 등으로도 이용되고 있다. 미국과 유럽 등에서는 생태계 교란 방지를 위해 4배체 물억새(M. sacchariflorus)와 2배체 참억새(M. sinensis)의 종간 교잡 이질 3배체인 불임성 억새(M. x giganteous)을 주로 재배하고 있으나, 단일 유전형의 품종으로 병해충과 자연재해에 취약하여 다양한 억새 품종의 개발이 시급한 실정이다. 본 연구는 억새를 재료로 하여 반수체 및 배수체 확보를 통한 배수성 별 특성 평가와 함께 기내배양을 통해 탈분화 및 재분화 시스템을 구축하여 억새의 육종 효율을 높이기 위해서 실시하였다. 억새 종자로부터 캘러스의 유도는 MS배지와 N6배지에 1mg/L 2.4-D를 첨가하였을 때 비배발생 캘러스(nonembryogenic callus)가 유도되었고, N6배지에 3~5 mg/L 2,4-D를 첨가하였을 때 배발생 캘러스(embryogenic callus)가 발생하였다. MS배지보다는 N6배지에서 캘러스 유도율이 높았으며, 식물생장조절제로 2,4-D와 BA 조합처리 보다 2,4-D 단용 처리하였을 때 캘러스 유도율이 더 높았다. 억새 종에 따른 캘러스 유도율은 물억새가 25.2~49.3%, 참억새는 30.3~52.0%였고 거대억새는 62.6~81.1%로 나타났다. 억새 신초 및 줄기로부터의 캘러스 유도율은 물억새가 4.4~17.2%, 참억새는 1.8~7.7%, 거대억새는 15.3~19.9%로 나타나 종자에 비해 매우 낮았다. 미성숙화기로부터의 캘러스 유도는 억새 종에 따른 차이가 없었으며, 3mg/L 2,4-D 첨가 배지에서 캘러스 유도율이 비교적 낮았고(60~80%), 1mg/L와 5mg/L의 2,4-D가 첨가된 배지에서 캘러스 유도율이 높게(90~95%) 나타났다.

• Korean Journal of Clinical Pharmacy
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• v.9 no.2
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• pp.81-87
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• 1999

췌장이식의 성공률은 지난 10년 동안 상당히 상승되었다. International Pancreas Transplant Registry에 따르면 1995년 이래 미국에서만 매년 1,000건 이상의 췌장이식이 실시되고 있다. 장기이식후 나타나는 급성 거부반응은 이식 후 6개월 이내에 가장 높은 빈도수로 나타난다. 췌장이식환자에서는 신장을 이식한 것보다 두배나 높은 거부반응을 나타나며 이로 인한 입원율의 증가 항림프제(antilyinphocyte) 사용과 감염의 증가로 이환율이 높다. 더구나 Cyclosporine (CsA)을 기초로 한 면역억제제요법의 사용은 높은 급성 거부반응률(acute graft rejection)을 초래하여 이식한 장기의 조직손실이 문제가 되고 있다. 새로운 면역억제제인 Tacrolimus (FK506)의 사용은 이식환자에서의 거부반응을 감소시켜 생존율을 증가시키는 것으로 알려져 있다. Tacrolimus는 neutral macrolide로 cyclic peptide인 CsA과는 화학 구조는 매우 다르나 비슷한 면역억제 효과를 보인다. 하지만 Tacrolimus의 사용시 신경독성, 신독성, 특히 고혈당증의 발생률이 높아 일부 이식센터에서는 장기 이식 후에 사용하기를 꺼리기도 한다. 하지만 여러 연구논문에서 간과 신장 이식 후 급성 거부반응 예방에 Tacrolimus는 CsA에 비해 이점이 있는 결과를 발표하였다. 결과적으로, 현재 췌장이식 후 Tacrolimus를 기초로 한 면역억제의 효과에 대한 연구가 활발히 진행중이다. 따라서 본 연구에서는 1994-1996년 사이에 Tacrolimus 또는 CsA를 기초로 한 면역억제요법을 투여 받은 췌장이식환자 101명을 후향적으로 조사하여 Tacrolimus (n=54)와 CsA(n=57)의 급성 거부반응 예방 효과와 신부전 발생률을 비교하였다. 모든 환자는 항림프구 약물, Azathioprine, Prednisone을 이식 후 면역억제제로 투여 받았다 기준선으로부터 $20\%$ 이상의 혈청 creatinine의 상승이 있는 환자에서는 급성 신부전으로 정의하였고 신장생검법으로 거부반응을 진단하였다 Matched-pair analysis에 따르면 췌장이식환자의 6개월 생존율은 CsA군에서 $97\%$, Tacrolimus군에서 $96\%$로 별다른 차이가 없었으며 (p=0.57), 6개월간의 이식한 췌장의 보존율은 CsA군에서는 $88\%, Tacrolimus에서 $91\%$. 유의한 차이는 없었다(p=0.29). 췌장이식 후 6개월 동안 Tacrolimus의 사용은 생검으로 증명되는(biopsy-proven) 급성 거부반응의 발생빈도는 CsA보다 유의하게 낮았을 뿐만 아니라 (p<0.05) 거부반응 증상의 심각도 또한 감소시켰다 (p=0.03). 급성거부반응 발생빈도의 감소로 Tacrolimus군에서 antilymphocyte 치료가 유의하게 줄어들었다(p=0.01). CsA군에서 Tacrolimus보다 신부전의 발생률이 높았으나 통계학적 차이는 없었다. 췌장이식후의 최적의 면역억제요법의 결정하기 위해서는 향후 Tacrolimus와 CsA을 비교하는 전향적 무작위 연구가 필요하다.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.244-252
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• 2006

The aims of this study were to determine if flowable composites can be used as pit and fissure sealants without bonding agents. Three flowable composites(Filtek Flow, Tetric Flow, Charmfil Flow) and a filled sealant (Ultraseal XT plus) were used. The pattern of resin tag formation in the four sealant materials were compared using SEM. For the microleakage assessment, 54 extracted human premolar teeth were randomly divided into 3 groups containing 18 premolars each. In each group, a conventional filled sealant and one of the three flowable composites were applied to occlusal fissures. The teeth were thermocycled(1200 cycles between $5^{\circ}{\pm}2^{\circ}C\;and\;55^{\circ}{\pm}2^{\circ}C$ with a dwell time of 30 seconds) and immersed in a 1% methylene blue solution for 48 hours. Each tooth was sectioned and examined to determine the extent of dye penetration. Three flowable composites and a filed sealant showed a similar resin tag formation pattern. The three flowable composites showed significantly more microleakage in each group than the filled sealant. The level of microleakage was similar in the three flowable composites. Flowable composites are not recommended as pit and fissure sealants because more microleakage can occur even when occlural fissures are mechanically widened.

• Journal of the Korean Geographical Society
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• v.36 no.5
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• pp.578-592
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• 2001

Based on a survey sample of farm households in three provinces of Korea, this article reports the perspectives of fuel-time farmers regarding trade liberalization, its effects on their lives, and the future of small-scale farming. While the agricultural sector is being transformed under neoliberal policies, farmers, with life or no preparation for a global market order, are forced to modernize their farming operations. The findings from the survey indicate that farmers accede to terms of global integration in principle while disapproving state rural policies in practice. The survey data also confirm that intra-regional differences in farmers'perceived satisfaction with living conditions, government farm policies, and socio-economic/labor issues. Disparities in the degree of discontent with government policies and socio-economic well-being are explicit between the relatively diversified region of Kyonggi Province and the farming-dependent regions of Chunbuk and Kyongbuk Provinces. The overall findings uphold that most farmers who have not been fully exposed to free market mechanisms are confronted by increased uncertainties and economic hardships. The findings propound that agricultural/rural policies need to reflect long-term, macroeconomic changes, and regionally/locally-based agricultural structure.

• Korean journal of applied entomology
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• v.44 no.3 s.140
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• pp.243-249
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• 2005

We investigated the repellency of eight mosquito repellents against Culex pipiens pallens and Aedes albopictus, and the quantity of DEETs were analysed by using gas chromatography. Ae. albopictus showed higher bloodsucking efficacy than Cx. pipiens pallens of the two subjects mouse and human hands, and human hand was more efficacious method for mosquito bloodsucking efficacy than mouse. Among the eight repellents were tested with mouse as subjects for eight hours, product C, G, and H were high repellency than others. In the case of human hands as subject, product C was highly effective than above other products. The DEET quantities of eight repellants varied from 7.31 g to 38.9 g in 100 g contents and we ascertained that there was a correlation between mosquito repellency and the DEET quantities remained after the treatments. It was evidenced from the long term test with shirt piece, in this test the Ae. albopictus attack was increased when the DEET quantity decreased below 40%.

• Journal of Adhesion and Interface
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• v.2 no.3
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• pp.25-32
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• 2001

Ethyl cyanoacrylate (ECA) is used as an instant adhesive, and it can be readily polymerized by moisture in air without any initiator and applied for industrial products and ohome use. However, pure ECA monomer is low-viscosity liquid at room temperature that flows into substrate surface. To thicken the instant adhesive, poly(methyl methacylate)(PMMA) is often added in it commercially. Another disadvantage of instant adhesive polymer is its brittleness In this study, functional polymers including PMMA for an additive of ECA were prepared to increase viscosity of the monomer and flexibility of the adhesive atthe same time The additives, P(MMA-VAc-EVE), were synthesized by radical copolymerization of MMA with VAc and EVE having low glass transition temperature (Tg). The additives were added to ECA to get functional instant adhesives. The chemical structures of the additives and ECA polymers were confirmed by $^1H$ NMR and FTIR, and their physical and mechanical properites were also evaluated. The Tg of the obtained additives decreased with increasing the content of VAc or VAc-EVE, indicating more improved flexibility. In addition, functional instant adhesive containing the additives showed higher bonding strength than that of the existing one.

• Journal of Veterinary Clinics
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• v.31 no.6
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• pp.502-506
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• 2014

Recently nano particles have proven for wide array of bioactive properties. In the present study, antibacterial properties of chitosan silver nano composites (CAgNCs) were investigated against fish pathogenic Edwardsiella tarda. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CAgNCs against E. tarda were $25{\mu}g/mL$ and $125{\mu}g/mL$, respectively. The field emission scanning electron microscope (FE-SEM) image of CAgNCs treated E. tarda showed the strongly damaged bacteria cells than non-treated bacteria. Furthermore, treatment of CAgNCs induced the level of intracellular reactive oxygen species (ROS) in E. tarda cells in concentration and time dependent manner suggesting that it may generate oxidative stress leading to bacterial cell death. In addition, MTT assay results showed that the lowest cell viability at $100{\mu}g/mL$ of CAgNCs treated E. tarda. Overall results of this study suggest that CAgNCs is a potential antibacterial agent to control pathogenic bacteria.

• Journal of Life Science
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• v.18 no.4
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• pp.494-502
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• 2008

The anaphylaxis shock reaction on the whole cells of H. pylori exhibited a symptom of slight illness for the first and second medication of causing antigen at an antigen concentration of WC (H) $60\;{\mu}g/100\;{\mu}l$ for WC (H) and no anaphylaxis shock symptom was observed at an antigen concentration of $20\;{\mu}g/100\;{\mu}l$ for WC (L). In the case of anaphylaxis shock reaction on the crude urease, no symptom was observed at an antigen concentration of $20\;{\mu}g/100\;{\mu}l$ for both urease (L) and urease (H). In the heterologous passive cutaneous anaphylaxis (PCA) test using a guinea pig-rat, no positive reaction was detected in all the medication groups of WC (H), WC (L), urease (H) and urease (L). In the skin sensitization test, it was observed that the best antigen concentration not causing skin disorder at each of $80\;{\mu}g/100\;{\mu}l$, $40\;{\mu}g/100\;{\mu}l$, $20\;{\mu}g/100\;{\mu}l$, and $20\;{\mu}g/100\;{\mu}l$ was $40\;{\mu}g/100\;{\mu}l$.

• Korean Journal of Food Science and Technology
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• v.33 no.5
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• pp.582-588
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• 2001

To control the growth of Salmonella on raw chicken supplied in food service, they were isolated and analysed for their physiological characteristics. Total viable microbe counts under the skin of the chicken amounted to 10% of numbers on their skin. Fifty one of Salmonella were isolated and identified from 75 chicken carcass samples. About 70% of the isolates showed resistance to more than four antibiotics, which indicated very high resistance among the strains ever reported in Korea. Lactic acid and trisodium phosphate(TSP) as sanitizing agent were applied to the Salmonella spp. isolates by agar diffusion method. The resistance by isolates to those sanitizing agents was compared with type strains of S. typhimurium ATCC 14028, S. typhimurium ATCC 12023, S. heidelberg and S. enteritidis. The isolates showed similar or less resistance to the type strains as for the lactic acid. However, as for trisodium phosphate known recently as a good sanitizer, 50% of the isolates showed more resistant compared with the type strains. Also, the treatment time and regeneration medium affected significantly the resistance of the isolates, which indicates that more careful test might be needed for TSP's practical application to raw chicken. Therefore, From the results, it is suggested that antibiotic treatment during breeding broiler and contamination after slaughtering should be minimized along with careful use of sanitizing agent in order to ensure more safe raw chicken supply.