• Composites Research
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• 제14권6호
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• pp.1-8
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• 2001

본 연구에서는 샌드위치 패널 구성 요소인 면재와 심재를 변화시켜 4종류의 샌드위치 패널을 제작하였다. 그리고 제작된 샌드위치 패널의 기계적 특성과 철도차량 개발시 중요한 요인으로 작용하는 음향투과 특성 그리고 화재에서의 안정성을 확인하기 위하여 난연특성 실험을 통하여 샌드위치 패널의 특성을 검토하고자 하였다. 샌드위치 패널의 기계적 특성은 알루미늄 면재 + 알루미늄 하니컴 심재로 구성된 샌드위치 패널이 면방향 인장강도와 변방향 압축강도 특성에서 우수하며 알루미늄 면재 + 노멕스 하니컴 심재로 구성된 샌드위치 패널은 면방향 압축강도와 굽힘 강도가 우수한 것으로 확인되었다. 알루미늄 면재 + PMI 포옴 심재로 구성된 샌드위치 패널은 심재의 전단강도 및 면재의 굽힙강도가 우수하였다. 난연성 시험에서는 phenol 수지 면재와 2종의 외국 면재는 모든 시험 결과에서 유사한 견과를 확인하였다.

• 혜화의학회지
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• 제19권1호
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• pp.49-54
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• 2010

Inhalational drug is an attractive modality for local therapy of pulmonary diseases as well as systemic drug delivery. Flower of Lonicera japonica (FLJ) and flower of Tussilag farfara (FTF) are medicinal herbs for respiratory disease in traditional Korean medicine. As a preliminary study for effective inhalable formulation of FLJ and FTF, this study was to provide the toxicity and anti-inflammatory effect on murine macrophages. The dried FLJ and FTF were extracted with distilled water, filtered and freeze-dried. After treatment with FLJ and FTF extract on RAW 264.7 cells, the cell viabilities were measured by MTT assay. FLJ and FTF did not show cytotoxicity on RAW 264.7 cells. LPS stimulated RAW 264.7 cells were treated with 3 and $30\;{\mu}g/ml$ of FLJ or FTF. FLJ and FTF did not inhibit TNF-a and IL-6 secretion in both concentration of treatment. We suggest that FLJ and FTF may be useful drugs for respiratory disease. Future work will focus on the physical characteristics for inhalable formulation.

• Bulletin of the Korean Chemical Society
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• 제34권1호
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• pp.174-178
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• 2013

A highly reliable dealkylation protocol of alkyl aryl ethers, whose alkyl groups are longer than methyl group, has been developed. We report that various ethyl, n-propyl, and benzyl aryl ethers are successfully cleaved using an ionic liquid, 1-n-butyl-3-methylimidazolium bromide, [bmim][Br], under microwave irradiation. Despite many characteristics such as lower cost and less toxicity of the alkylating agents, and greater hydrophobicity of the products, longer alkyl ethers have been significantly less exploited than methyl ethers, probably due to more difficulty in the deprotection step. Since it has the same advantages as the demethylation method developed by this group including mild conditions, short reaction time, and small use of the ionic liquids, the dealkylation protocol can greatly encourage the broader use of longer alkyl groups in the protection of phenolic groups. As with our previous study of demethylation using [bmim][Br], the microwave irradiation is crucial for the deprotection of longer alkyl aryl ethers. Unlike the conventional heating, which causes either low conversion or decomposition, the microwave irradiation seems to more effectively provide energy to cleave the ether bonds and therefore suppresses the undesired reactions.

• Journal of Microbiology and Biotechnology
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• 제12권2호
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• pp.235-241
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• 2002

Sophorolipid, a biosurfactant produced from Candida bombicola ATCC 22214, showed antimicrobial activity against Bacillus subtilis, Staphylococcus xylosus, Streptococcus mutans, and Propionibacterium acne at 4, 1, 1, 0.5 ppm, respectively. Also, 100 ppm of sophorolipid inhibited $50\%$ of cell growth of plant pathogenic fungus, Botrytis cineria. However, sophorolipid showed no effect on Escherichia coli, indicating that its selective antimicrobial activity depended on the cell wall structure. Treatment of B. subtilis with sophorolipid increased leakage of intracellular enzyme, malate dehydrogenase, indicating a possible interaction of sophorolipid with a cellular membrane. Comparing lactone-type and acid-type sophorolipids, the former showed a higher antimicrobial activity. Supplementing other surfactants showed no significant effects on the antimicrobial activity. Animal study showed that 5 g of sophorolipid per kg body weight by oral administration caused no toxicity, and sophorolipid induced no irritation on the skin. These results show potential use of sophorolipid as an active ingredient in healthcare products.

• Environmental Engineering Research
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• 제15권1호
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• pp.15-21
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• 2010

This study was conducted to evaluated seawater bacteria and their seasonal characteristics in the arsenic contaminated coastal seawater of Yeosu Bay, the Republic of Korea. Arsenite-oxidizing bacteria play an important role in the seawater of the arsenic contaminated bay, with a variety of arsenic resistance system (ars) genotypes being present during summer. Specifically, Bacillus sp. strain SeaH-As22w (FJ607342), isolated from the bay, were found to contain the arsB, arrA and aoxR type operons, which are involved in arsenic resistance. The isolated bacteria showed relatively high tolerance to sodium arsenite (III; $NaAsO_2$) at concentrations as high as 50 mM. Additionally, batch seawater experiments showed that Bacillus sp. strain SeaH-As22w completely oxidized 1 mM of As (III) to As (V) within 10 days. Ecologically, the arsenic-oxidizing potential plays an important role in arsenic toxicity and mobility in As-contaminated coastal seawater of Yeosu Bay during all seasons because it facilitates the activity of Bacillus sp. groups.

• 대한금속재료학회지
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• 제50권1호
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• pp.86-91
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• 2012

Ti-6Al-4V extra low interstitial (ELI) alloy has been widely used as an orthopedic implant material because of its excellent biocompatibility, corrosion resistance and mechanical properties. However, V-free titanium alloys such as Ti-6%Al-7%Nb and Ti-5%Al-2.5%Fe have recently been developed because of the toxicity of V. Hydroxyapatite (HA) is used as a coating material on Ti or Ti biomaterials due to its good biocompatibility. However, HA coated on Ti alloy causes a problem for tissue by peeling off during usage. Therefore, such peeling off during long time usage can be suppressed by adding HA in Ti or Ti alloy composites. The aim of this study was to manufacture an ultra fine grained (UFG) Ti-Nb-HA bulk alloy, which is usually difficult to fabricate using melting and casting technology, by rapid sintering process using high energy mechanical milled (HEMM) powder.

• 한국미생물·생명공학회지
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• 제47권2호
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• pp.269-277
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• 2019

In the present study, we have studied the bioremediating capability of bacterial strain against six heavy metals. The strain was isolated from river Yamuna, New Delhi which is a very rich repository of bioremediating flora and fauna. The strain was found to be Gram positive as indicated by Gram staining. The strain was characterized using 16s rRNA gene sequencing and the BlastN result showed its close resemblance with the Cellulosimicrobium sp. As each treatment has its own toxicity eliciting expression of different factors, we observed varied growth characteristics of the bacterial isolate and its protein content in response to different heavy metals. The assessment of its bioremediation capability showed that the strain Cellulosimicrobium sp. has potential to consume or sequester the six heavy metals in this study in the following order iron > lead > zinc > cooper > nickel > cadmium. Thus, the strain Cellulosimicrobium sp. isolated in the present study can be a good model system to understand the molecular mechanism behind its bioremediating capabilities under multiple stress conditions.

• 한국환경복원기술학회지
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• 제22권1호
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• pp.47-59
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• 2019

This study was composed of four treatments [no treatment, phosphate + limestone layer treatment, phosphate + sodium bicarbonate + cement layer treatment, and phosphate + sodium bicarbonate + limestone layer treatment] for figuring out vegetation effects on the acid drainage slope. Treated acid neutralizing techniques were effective for neutralizing acidity and vegetative growth in order of [first: phosphate + sodium bicarbonate + limestone layer treatment, second: phosphate + sodium bicarbonate+cement layer treatment, third: phosphate + limestone layer treatment and fourth: no treatment] on the acid drainage slope. We found out that sodium bicarbonate treatment was additory effect on neutralizing acidity and increasing vegetaive growth besides phosphate and neutralizing layer treatments. In neutralizing layer treatments, Limestone layer was more effective for vegetation and acidity compared to cement layer treatment. Cement layer showed negative initial vegetative growth probably due to high soil hardness and toxicity in spite of acid neutralizing effect. Concerning plants growth characteristics, The surface coverage rates of herbaceous plants, namely as Lotus corniculatus var. japonicus and Coreopsis drummondii L were high in the phosphate + sodium bicarbonate + limestone layer treatment while Festuca arundinacea was high in the phosphate + sodium bicarbonate + cement layer treatment. We also figured out that soil acidity affected more on root than top vegetative growth.

• 한국응급구조학회지
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• 제24권3호
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• pp.117-128
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• 2020

Purpose: This study analyzed the information and accessibility of toxic substances provided to Internet websites. Methods: From August 1, 2020, to August 31, 2020, we analyzed eight internet websites regarding toxic pharmaceuticals, pesticides, and chemicals. The website-evaluation criteria were divided into five categories for information and five categories for website convenience. Results: All eight websites about toxic substances were hosted by reliable institutions or organizations and provided accurate information in terms of informational relevance. The website run by the Safety and Health Corporation scored the highest with 100points. Analysis of the websites' accessibility to non-members' revealed that six (75.0%) were accessible, but two (12.5%) provided only limited information. Access to information through mobile apps was only available in three of the eight cases (37.5%). Conclusion: This study can be used as a reference for Internet websites about toxic substances. Toxicological information that can be viewed only with membership and manager approval requires membership in advance of viewing. In addition, emergency medical personnel working at a site or hospital should be familiar with the characteristics of toxicity information retrieval.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.283.2-283.2
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• 2002

Organochlorine pesticides and polychlorinated biphenyls (PCBs) have been used intensively in agriculture and industry for a long time. They belong to a group of contaminants whose occurrence in the environment is a serious concern to environmental chemists and toxicologists due to their resistance to degradation in the environment as well as their potential toxicity. Also. the lipophilic characteristics of these substances are responsible for their ability to bioaccumulate in tissues and organs rich in lipids of men and animals through food chain. Therefore, the measure of the levels of organochlorine pesticides and PCBs in human tissues are good markers in detemining the extent to exposure and evaluating the hazards. This study was preformed to compare concentrations of organochlorine pesticides(${\alpha}-BHC, {\beta}-BHC, {\gamma}-BHC, {\delta}-BHC$, p.p'-DDT,p.p'-DDD,p.p.'-DDE. endrin. dieldrin. aldrin) and seven marker PCBs(PCB nos. 28. 52. 101. 118. 138. 153. 180) in liver. kidney cortex, lung blood and adipose tissue collected at autopsies of 10men and 10 women using gas chromatography equipped with electron capture detector to express the data on a lipid adjusted basis. From the results, the significant differences in the levels of organochlorines of PCBs between sexes, districts where they had lived and ages were also investigated.