• 생명과학회지
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• 제29권11호
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• pp.1227-1234
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• 2019

매실은 한국, 일본 및 중국 등지에서 섭취하여온 과실로서 유기산이 풍부하며, 다량의 무기질 및 폴리페놀 성분을 함유한 것으로 알려져 있다. 이러한 매실을 이용하여 예로부터 절임이나 청 등으로 가공하여 섭취할 뿐만 아니라 구토, 해독 및 해열에 효능이 있는 한약재로서 사용해왔다. 본 연구에서는 매실을 이용하여 분획물을 제조하고 각각의 인체 대장암세포에 대한 성장 억제효과를 확인하였으며, colony 형성능, 형태학적 관찰, apoptotic body 형성, 단백질 변화 및 환경호르몬에 대한 방어 효과를 평가하였다. 매실 분획물의 인체 대장암세포 HT-29에 대한 증식 억제효과는 매실 메탄올 분획물(maesil methanol fraction, MMF) 및 매실 부탄올 분획물(maesil, butanol fraction, MBF)이 가장 뛰어난 효능을 나타내었다. MMF 및 MBF의 처리에 따라 colony 형성능 또한 농도의존적으로 감소하는 것으로 나타났으며 형태학적 변화 또한 확인할 수 있었다. 핵의 형태학적 변화를 관찰한 결과 $125{\mu}g/ml$의 MMF 및 MBF 처리에 따라 apoptotic body의 형성 및 핵 응축을 관찰하였다. MMF 및 MBF의 처리에 따른 인체 대장암세포의 성장 억제효과가 apoptosis 와 관련이 있는지 단백질의 변화를 확인한 결과, pro-apoptotic 단백질은 Bax, caspase-3, PARP의 발현이 농도의존적으로 증가하는 경향을 나타내었으며, anti-apoptotic 단백질인 Bcl-2의 발현은 감소하는 경향을 나타냈다. 또한, 환경호르몬의 일종은 bisphenol A (BPA)에 의해 성장이 증식된 HT-29세포는 MMF의 처리에 따라 유의적인 성장억제 효과를 갖는 것을 확인할 수 있었다. 따라서 본 연구를 통해 얻은 결과는 매실 분획물을 이용한 기능성 식품 소재화에 대한 기초 자료로 활용될 수 있을 것으로 판단된다.

• 상하수도학회지
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• 제21권2호
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• pp.203-214
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• 2007

This study aimed at researching the process selection for two-stage and dual media filtration system, as a technology substituting the existing sand filter without expanding the site when retrofitting an old filter bed or designing a new one. In order to select the process for optimum complex filtration system, three running conditions have been tested. Test results demonstrated that Run 3 in which the 1st stage was filled with anthracite and coarse sand, and the 2nd stage was filled up with activated carbon and fine sand reduced the head loss and the load of turbidity substances. Also, Run 3 showed better performance in removing TOC, particle counts, THMFP and HAAFP, compared to other two conditions. 99 % of Cryptosporidium was removed. Bisphenol-A was rarely removed from the 1st stage of coarse sand and 2nd stage of fine sand, but 99 % of it was removed from the 2nd stage of activated carbon. In conclusion, when it is required to retrofit an old rapid filter bed or design a new one for the purpose of improving filtration performance, the following two-stage and dual media filtration system is suggested: the 1st stage of filter bed needs to be filled up with coarse sand to remove turbidity as the pretreatment for extending duration of filtering, the top part of 2nd stage needs to be filled up with granular activated caron to remove dissolved organic matters and others as the main process, and finally the bottom part of 2nd stage needs to be filled up with fine sand as the finishing process.

• Asian Pacific Journal of Cancer Prevention
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• 제13권12호
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• pp.5937-5946
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• 2012

The term endocrine disruptors is used to describe a variety of natural and manmade substances that have the capacity to potentially interfere with and modify the normal physiology of endocrine system either by mimicking, blocking or modulating the actions of natural endogenous hormones. The rising incidence of breast cancer over the last 50 years and the documented higher incidence in urban as compared to rural areas suggest a relationship to the introduction and increased use of xenoestrogens in our environment. The literature has developed over the last decades where initial experiments on endocrine disruptors did not support an involvement in breast cancer, and then evidence mounted implicating various environmental factors including hormones, endocrine disrupting chemicals and non-endocrine disrupting environmental carcinogens in the pathogenesis of breast cancer. Available data support the hypothesis that exposure to endocrine disruptors in utero leaves a signature on mammary gland morphogenesis so that the resulting dysgenic gland becomes more predisposed to develop tumors upon exposures to additional insults later on during life. Exceptionally, exposure to phytoestrogens could be beneficial to human health. Most of the available data are from well developed countries while the developing countries are still understudied regarding these issues. Here, we raise a note of caution about potential role of environmental toxins including endocrine disruptors in breast cancer development and call for serious measures to be taken by all involved parties in the developing world.

• 대한수의학회지
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• 제45권4호
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• pp.545-552
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• 2005

The major protocol features of the rodent uterotrophic assay have been evaluated using a range of reference chemicals. The protocol variables considered include the selection of the test species and route of chemical administration, the age of the test animals, the maintenance diet used, and the specificity of the assay for estrogens. The rodents were ovariectomized under general anesthesia via bilateral flank incisions and randomly assigned to groups of 5 animals. Chemicals were DEHP, DBP, BPA and NP, were injected sc once daily with combinations of chemicals treatments for 3 days. In the results, the reported estrogenic chemicals DEHP and DBP were both negative in the single dose treatments. But, in the combinations of chemicals treatments, DEHP and DBP increased in bud number of mammary gland. Treatment of ovariectomized mice with combinations of other chemicals resulted in uterine and vaginal hyperplasia. The additive estrogenic effects were seen with the combinations of $17{\beta}$-Bestradiol and DBP treatment. the competitive estrogenic effects were seen with the combinations of $17{\beta}$-Bestradiol and nonylphenol, $17{\beta}$-Bestradiol and bisphenol-A treatments. These results offers a sysmatic and mechanistically informative approach to assessing estrogenicity. it provides a useful profile of activity using a reasonable amount of resources and is compatible with the study of individual chemicals as well as the investigation of interactions among combinations of chemicals. The results described illustrate the intrinsic complexity of evaluating chemicals for estrogenic activities and conform the need for rigorous attention to experimental design and criteria for assessing estrogenic activity.

• 한국대기환경학회지
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• 제34권4호
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• pp.616-624
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• 2018

In this study, a previous DNPH (2,4-dinitrophenylhydrazine) coupled with high performance liquid chromatography (HPLC) method to measure the concentration of formaldehyde in ambient and source environments has been improved. To improve the disadvantage of the previous HPLC method, an appropriate composition ratio of mobile phase (water: acetonitrile (ACN)) was determined and an isocratic analysis was conducted. Furthermore, limit of detection (LOD), limit of quantitation(LOQ), accuracy, and precision were investigated to verify the reliability of the analytical conditions determined. Finally, samples of exhaust gases from five different industrial facilities were applied to HPLC analytial method proposed to determine their formaldehyde concentrations. The appropriate composition ratio of the mobile phase under the isocratic condition was a mixture of water(40%) and ACN(60%). As the volume fraction of the organic solvent ACN increases, retention time of the formaldehyde peak was reduced. Detection time of formaldehyde peak determined using the proposed isocratic method was reduced from 7 minutes(previous HPLC method) to approximately 3 minutes. LOD, LOQ, accuracy, and precision of the formaldehyde determined using standard solutions were 0.787 ppm, 2.507 ppm, 93.1%, and 0.33%, respectively, all of which are within their recommended ranges. Average concentrations of the formaldehyde in five exhaust gases ranged from 0.054 ppm to 1.159 ppm. The lowest concentration (0.054 ppm) was found at samples from waste gas incinerator in a bisphenol-A manufacturing plant. The highest was observed at samples from the absorption process in manufacturing facilities of chemicals including formaldehyde and hexamine. The analytical time of the formaldehyde in ambient air can be shortened by using the isocratic analytical method under appropriate mobile phase conditions.

• Restorative Dentistry and Endodontics
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• 제24권4호
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• pp.604-613
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• 1999

This study was performed to evaluate the effect of resin and filler type on the fracture toughness of light-activated composites. Experimental composites were prepared using urethane tetramethacrylate(UTMA) and bisphenol glycidylmethacrylate(Bis-GMA) monomers and five different types of silica fillers. Fracture toughness was measured by a single edge V-notched beam(SEVNB) method, which was discussed from ASTM E399-78. Rectangular bars of $2.5{\times}5{\times}26mm$ were prepared with experimental composites and a notch about 2.25mm deep was carved at the center of the long axis of the specimen using a dental diamond disk driven by a dental micro engine. The flexural test was carried out at a crosshead speed of 0.05mm/min and fracture surfaces were observed under scanning electron microscope. The results obtained were summarized as follows: 1. The fracture toughness values of UTMA-based composites were relatively higher than those of Bis-GMA-based composites. 2. The highest fracture toughness value was observed in the UTMA-based composite containing the $1.5{\mu}m$-spherical fillers. 3 Aging in the distilled water at $37^{\circ}C$ for 10 days showed the increase of fracture toughness, which was severer in the Bis-GMA-based composites than those of UTMA-based composites. 4. The AE amplitude occurring during the fracture toughness tests was the highest at the point of macroscopic fracture.

• Reproductive and Developmental Biology
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• 제35권4호
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• pp.475-478
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• 2011

In the present study, the effect of cysteine and NT or bisphenol A(BP) on in vitro aturation(IVM) of porcine oocytes were examined. COCs was cultured in NCSU-23 medium supplement with 10% FCS which had previously been covered with mineral oil and equilibrated in a humidified atmosphere of 5% $CO_2$ and 95% air at $38^{\circ}C$. The IVM rate of oocytes cultured for 48 hrs in NCSU-23 medium supplement with 0.5~10.0 mM cysteine were $34.0{\pm}3.2%$, $36.0{\pm}3.5%$, $48.0{\pm}3.8%$, $22.0{\pm}3.2%$, respectively. The IVM rate of oocytes cultured in NCSU-23 medium supplement with 0.5~5.0mM NT for 48 hrs were $24.0{\pm}4.2%$, $18.0{\pm}4.9%$, $8.0{\pm}2.2%$, respectively. NT affects oocyte in vitro maturation rate in a dose-dependent. This result were significantly lower than the control group. The IVM rate of oocytes cultured for 48 hrs in NCSU-23 medium supplement with 1.0 mM NT+5.0 mM cysteine($38.0{\pm}4.3%$) were significantly higher than that of NT treatment. The IVM rate of oocytes cultured in NCSU-23 medium supplement with 0.05~5.0 mM BP for 48 hrs were $20.0{\pm}4.7%$, $10.0{\pm}5.3%$, $6.0{\pm}3.2%$, respectively. The IVM rate of oocytes cultured in NCSU-23 medium supplement with BP was significantly lower cultured non supplement of BP ($44.0{\pm}3.5%$). BP affects porcine oocyte maturation rate in a dose-dependent manner. The IVM rate of oocytes cultured for 48 hrs in NCSU-23 medium supplement with 1.0 mM BP+5.0 mM cycteine ($32.0{\pm}3.2%$) were increased than that of BP treatment.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3706-3710
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• 2012

A novel silicon-containing arylacetylene resin (MSAR) modified by dipropargyl ether of bisphenol A (DPBPA) and dipropargyl ether of perfluorobisphenol A (DPPFBPA) was prepared separately. The curing behaviors of modified resins, DPBPA/MSAR and DPPFBPA/MSAR, were characterized with differential scanning calorimeter (DSC). The kinetic parameters of modified resins were obtained by the Kissinger and Ozawa methods. The results of dynamic mechanical analysis (DMA) revealed that the glass transition temperature ($T_g$) of the cured DPBPA/MSAR reached $486^{\circ}C$. According to the thermogravimetric analysis (TGA), the decomposition temperature ($T_{d5}$) of the cured resins and char yield ($Y_c$, $800^{\circ}C$) decreased as the dipropargyl ether loadings increased, especially in air. With the same weight loading, thermal stability of DPBPA/MSAR was better than that of DPPFBPA/MSAR. The carbon fiber (T300) reinforced composites exhibited excellent flexural properties at room temperature with a high property retention at $300^{\circ}C$.

• 한국재료학회지
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• 제3권3호
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• pp.215-222
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• 1993

에폭시 수지를 개질하기 위하여 반응성 첨가제 Malononitrild(MN)을 Diglycidy1 ether fo vispenol A (CGEBA)/Methylene dianiline(MDA)계를 첨가하여 이 계의 경화 반응속도론과 경화반응메카니즘을 시차주사 열분석(DSC)과 적외선 흡수 분광법을 통해 관찰하였다. 경화반응속도론으로부터 MN으로 개질된 DGEBA/MDA는 완전히 경화를 이루기 위하여 $80^{\circ}C$로 부터 $170^{\circ}C$까지 $30^{\circ}C$간격으로 경화시킨 시료로 반응메카니즘을 고찰한 결과 PA(primary amine)-E(epoxide)그리고 E(epoxide)-OH(hydroxy1 group)반응 이외에 PA(primary amine)-CN(nitrile)과 CN(nitrile)-OH(hydroxy1 group)반응이 일어남을 알았다.

• 한국응용과학기술학회지
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• 제31권3호
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• pp.486-491
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• 2014

본 연구에서는, 유기용매를 사용하지 않는 친 환경적인 건식 공정과 초임계 공정을 이용한 Thin-multiwalled carbon nanotube (TWNTs)/아민계 에폭시 첨가제의 복합체 제조에 관하여 연구를 하였다. 제조된 TWNTs/아민계 에폭시 첨가제의 복합체는 우레탄기반의 비스페놀 A 타입의 에폭시 레진의 경화제로 사용하였다. TWNTs/아민계 에폭시 첨가제의 복합체를 경화제로 사용하여 제조된 에폭시 레진의 열적 성질을 Dynamic mechanical analysis (DMA)를 이용하여 분석 하였으며, 메트릭스상의 carbon nanotube의 높은 분산성은 SEM을 통하여 확인 하였다. 그 결과, 초임계 공정을 이용하여 제조된 에폭시 레진의 열적 성질과 매트릭스내의 carbon nanotube 분산성이 건식 공정을 사용 하였을 때 보다 더욱 증가된 결과를 확인 할 수 있었다.