• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.77-78
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• 2018

Form-work is a must for construction work. In order to secure the best condition of the form surface and to increase the number of times, the form releasing agent is applied during the process of the form-work. The base oil of the form release agent which has been used already uses the oil which directly or indirectly affects the natural environment and the concrete. In this study, the basic study on the form release agent for concrete was carried out only for the effect of adhesion. The adhesive force of the tile is measured by the mortar to determine the change of the releasing agent and the adhesive strength.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.969-972
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• 2008

본 연구는 온도변화에 따라 기초영향인자가 콘크리트와 알루미늄 거푸집간의 표면 마감성에 미치는 영향에 대하여 분석한 것으로 그 결과를 요약하면 다음과 같다. 육안관찰상 코팅합판과 무손상 알루미늄 거푸집의 경우 비슷한 결과를 나타냈으며, 온도변화에 따라서는 알루미늄 거푸집을 사용한 경우 온도가 높아질수록 표면품질이 약간씩 저하하는 것을 확인할 수 있었다. 표면조도의 경우 온도변화에 따른 차이는 거의 나타나지 않았으며, 박리제의 도포여부에 따른 차이가 발생하였다. 온도변화에 따른 표면공극분포는 온도가 증가할수록 $0.1{\sim}1mm$ 범위의 미세한 기포가 증가하여 화학반응이 촉진됨을 확인할 수 있었으며, 다른 범위의 공극도 증가하였다. 또한, 온도가 증가할수록 다른 인자들의 영향이 더욱 커지는 것을 확인할 수 있어 온도증가에 의해 알루미늄 거푸집을 이용하는 콘크리트의 표면품질이 저하함을 확인할 수 있었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 춘계 학술논문 발표대회
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• pp.47-50
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• 2008

This study analyzed the effect of increasing the number of times using aluminum form to the surface quality of concrete through small sized test, and the result was summarized as following. At the early stage, there was no remarkable change between aluminum and coated plywood form, and the surface quality of concrete both forms slightly declined corresponding with increasing the number of times using.As void on the surface corresponding to the number of times, the voids ranged 0.1~1mm were increased corresponding to increasing the number of times using forms, and the other range voids were also increased according to increasing the number of times using forms. It was confirmed that the surface of concrete was damaged gradually. For comparison with aluminum and coated plywood form though this experimental results, there might be no difference, if release agent was used properly.

• Journal of Pharmaceutical Investigation
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• 제40권3호
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• pp.181-185
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• 2010

The objective of this study was to improve the extent of drug release as well as the dissolution rate of TD49, a novel algicidal agent, via the preparation of solid dispersion (SD). Among the various carriers tested, $Solutol^{(R)}$ HS15 was most effective to enhance the solubility of TD49. Subsequently, SDs of TD49 were prepared by using $Solutol^{(R)}$ HS15 and their solubility, dissolution characteristics and drug crystallinity were examined at various drug-carrier ratios. Solubili ty of TD49 was increased significantly in accordance with increasing the ratio of $Solutol^{(R)}$ HS15 in SDs. Compared to untreated powders and physical mixtures (PMs), SDs facilitated the faster and greater extent of drug release in water. Particularly, SD having the drug-carrier ratio of 1:20 exhibited approximately 90% of drug release within 1 hr. Differential scanning calorimetry (DSC) thermograms and X-ray diffraction (XRD) patterns suggested that SDs might enhance the dissolution of TD49 by changing the drug crystallinity to an amorphous form in addition to the increased solubilization of drug in the presence of $Solutol^{(R)}$ HS15. In conclusion, SD using $Solutol^{(R)}$ HS15 appeared to be effective to improve the extent of drug release and the dissolution rate of poorly water soluble TD49.

• Archives of Pharmacal Research
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• 제5권2호
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• pp.61-70
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• 1982

Sulfisoxazole, a chemotherapeutic agent, was microencapsulated with ethylcellulose by means of phase separation form cyclohexane by temperatture change. The size distribution was determined by use of standard sieves and the effect of core to wall ratio was noted. To examine their shapes and usrface characteristics, the microcapsules were observed with a scanning electron microscope. Release of the drug from microcapsules into pH 7.5 buffer medium was studied. The release pattern was found to have similar properties to the release of a drug from an insoluble porous matrix reported. The apparent diffusion coefficient of sulfisoxazole was measured for the transport of the drug from the core of microcapsules into the surronding sink condition. The apparent diffusion coefficient increased with increasing capsule size.

• 한국산학기술학회논문지
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• 제16권11호
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• pp.7838-7843
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• 2015

본 논문에서는 제 2형 당뇨병의 1차 선택약으로 사용되는 메트포르민 염산염이 통상적으로 1일 1000mg~2000mg의 고용량으로 투여되고 동시에 매우 높은 수성용해도를 가지므로 1일 1회 복용을 위한 약물방출제어시스템에 다량의 서방성 부형제를 필요로 하여 제형의 크기가 커져 복용이 어려운 문제점이 있다. 따라서 이를 개선하고자 상대적으로 수성용해도가 낮은 새로운 메트포르민 산부가염을 합성하여 서방성 정제에 적용하여 메트포르민의 방출을 확인하고자 하였다. 이를 위해 메트포르민 염산염을 원료로 하여 NaOH하에서 메트포르민 base를 만들고 여기에 산부가염을 반응시켜 6개의 새로운 메트포르민 산부가염들을 합성하였다. 또한 이들의 수성용해도를 측정하여 메트포르민 염산염에 비해 현저히 낮은 수성용해도를 가지는 메트포르민 스테아린산염을 확인하였고 메트포르민 서방성 제형에 적용하여 실제 약물의 방출제어에도 용출시험 결과, 12시간에서 약 2배의 약물방출제어 효과를 확인하였다. 결론적으로 새로운 메트포르민 산부가염을 통해 서방성 부형제의 양을 줄여 제형의 크기를 줄임으로써 보다 높은 환자의 복약순응도를 기대할 수 있을 것이다.

• Archives of Pharmacal Research
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• 제27권3호
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• pp.314-318
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• 2004

Microglia are the major inflammatory cells in the central nervous system and become activated in response to brain injuries such as ischemia, trauma, and neurodegenerative diseases including Alzheimer's disease (AD). Moreover, activated microglia are known to release a variety of proinflammatory cytokines and oxidants such as nitric oxide (NO). Minocycline is a semi-synthetic second-generation tetracycline that exerts anti-inflammatory effects that are completely distinct form its antimicrobial action. In this study, the inhibitory effects of minocycline on NO and prostaglandin E$_2$ (PGE$_2$) release was examined in lipopolysaccharides (LPS)-challenged BV2 murine microglial cells. Further, effects of minocycline on inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression levels were also determined. The results showed that minocycline significantly inhibited NO and PGE$_2$ production and iNOS and COX-2 expression in BV2 microglial cells. These findings suggest that minocycline should be evaluated as potential therapeutic agent for various pathological conditions due to the excessive activation of microglia.

• Journal of Dairy Science and Biotechnology
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• 제23권2호
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• pp.115-123
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• 2005

Microcapsules consisting of natural, biodegradable polymers for controlled and/or sustained core release applications are needed. Physicochemical properties of whey proteins suggest that they may be suitable wall materials in developing such microcapsules. The objectives of the research were to develop water-insoluble, whey protein-based microcapsules containing a model water-soluble drug using a chemical cross-linking agent, glutaraldehyde, and to investigate core release from these capsules at simulated physiological conditions. A model water soluble drug, theophylline, was suspended in whey protein isolate (WPI) solution. The suspension was dispersed in a mixture of dichloromethane and hexane containing 1% biomedical polyurethane. Protein matrices were cross-linked with 7.5-30 ml of glutaraldehyde-saturated toluene (GAST) for 1-3 hr. Microcapsules were harvested, washed, dried and analyzed for core retention, microstructure, and core release in enzyme-free simulated gastric fluid (SGF) and simulated intestinal fluid(SIF) at $37^{\circ}C$. A method consisting of double emulsification and heat gelation was also developed to prepare water-insoluble, whey protein-based microcapsules containing anhydrous milkfat (AMF) as a model apolar core. AMF was emulsified into WPI solution (15${\sim}$30%, pH 4.5-7.2) at a proportion of 25${\sim}$50%(w/w, on dry basis). The oil-in-water emulsion was then added and dispersed into corn oil ($50^{\circ}C$) to form an O/W/O double emulsion and then heated at $85^{\circ}C$ for 20 min for gelation of whey protein wall matrix. Effects of emulsion composition and pH on core retention, microstructure, and water-solubility of microcapsules were determined. Overall results suggest that whey proteins can be used in developing microcapsules for controlled and sustained core release applications.

• Journal of Pharmaceutical Investigation
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• 제36권4호
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• pp.271-276
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• 2006

Felodipine, a calcium-antagonist of dihydropyridine type, is a poorly water soluble drug and has very low bioavailability. As preceding studies, use of solid dispersion systems and surfactants(solubilizers) has been suggested to increase dissolution and to improve bioavailability of felodipine. But in case of solid dispersion systems, large amount of toxic organic solvents should be used and manufacturing process time become longer than conventional process. In case of using surfactants, as time elapsed, decreasing of dissolution rate of felodipine due to crystallization has been reported. In this study, Copovidon as a hydrophilic polymer and $Transcutol^{\circledR}$ as a surfactant were combined to formulations if order to increase dissolution of felodipine and conventional wet granulation process were applied to manufacturing of formulations. The effect of Copovidon and $Transcutol^{\circledR}$ on the dissolution oi felodipine was investigated in-vitro. When Copovidon and $Transcutol^{\circledR}$ used simultaneously, the dissolution rate of felodipine was prominently increased compared with when used separately and the maximum increase in the dissolution of felodipine was 5.8 fold compared to control. This is most probably due to synergy effect by combination of Copovidon and $Transcutol^{\circledR}$. Felodipine sustained release tablets were successfully formulated using several grades of HPMC as a release retarding agent. The stability of felodipine sustained release tablet was evaluated after storage at accelerated condition($40^{\circ}C/75%\;RH$) for 6months in HDPE(High density polyethylene) bottle. Neither significant degradation nor change of dissolution rate for felodipine was observed after 6months. In conclusion, felodipine sustained release tablet was successfully formulated and dissolution of felodipine, poorly water soluble drug, was prominently increased and also stability was guaranteed by using combination system of hydrophilic polymer and surfactant.

• Journal of Nutrition and Health
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• 제36권4호
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• pp.382-388
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• 2003

(-)-Epigallocatechin-3-gallate (EGCG) is a polyphenolic compound found in peen tea leaves, and has been known to be one of the most potent catechin species which inhibits cell growth most possibly through an apoptotic cell death. We investigated the apoptotic activity of (-)-EGCG on the human myeloid leukemia cell line, HL-60. Our results of MTT test indicated that (-)-EGCG had a significant antiproliferation effect in HL-60 cells with $IC_{50}$/ (50% inhibition concentration) value of 65 $\mu$M. Giemsa statining of HL-60 cells treated with (-)-EGCG (100 $\mu$M) for 6hrs showed a typical apoptosis-specific morphological change including shrinkage of the cytoplasm, membrane blobbing and compaction of the nuclear chromatin. The DNA fragmentation was observed from the agarose gel electrophoresis of cells treated with (-)-EGCG for 3hrs or longer, and was progressed to a greater degree as treatment time increases. Treatment of the cells with (-)-EGCG (100 $\mu$M) resulted in a rapid release of mitochondrial cytochrome c into the cytosol, and a subsequent cleavage of caspase-3 to an active form in a treatment-time dependent manner. (-)-EGCG (100 $\mu$M) also stimulated proteolytic cleavage of poly-(ADP-ribose) polymerase (PARP) to an active form in HL-60 cells. Tlken together, (-)-EGCG appears to induce the apoptosis in human myeloid leukemia cells via a caspase-dependent pathway. These results suggest the possible application of (-)-EGCG, the major active compound in green tea, as an antiproliferative agent for cancer prevention.