• 한국화재소방학회논문지
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• 제18권2호
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• pp.67-72
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• 2004

본 연구는 작업장의 건축물이나 구조물의 구성요소로 사용되어지는 섬유강화플라스틱의 연소특성을 평가하였다. 섬유강화플라스틱의 연소특성은 ISO 5660에 따라 콘칼로리미터를 사용하여 수행하였다. 섬유 강화플라스틱의 착화시간과 열방출율은 복사열과 난연제의 함량에 따라 달랐다. 섬유강화플라스틱의 열방출율은 복사열의 증가에 따라 증가하였다. 섬유강화플라스틱의 착화시간과 최대 열방출율을 이용하여 플래쉬오버(Flashover)의 가능성을 Petrella가 제시한 분류방법에 따라 검토하였다.

• Archives of Pharmacal Research
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• 제8권3호
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• pp.159-168
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• 1985

In attempt to develop a drug delivery system using serum albumin microspheres, bovine serum albumin microspheres containing antitumor agent, cytarabine, were prepared. The shape, surface characteristics, size distribution, behavior of in vitro distribution, drug release behaior, and degradation of albumin microspheres in animal liver tissue homogenate and proteolytic enzyme were investigated. The shape of albumin microspheres was spherical and the surface was smooth and compact. The size distribution of the albumin microspheres was affected by dispersion forces during emulsification and albumin concentration. Distribution of albumin mirospheres after intravenous administration in rabbit was achieved immediately. In vitro, albumin microsphere matrix was so hard that it retained most of cytarabine except initial burst during the first 10 minutes, and the level of drug release during the initial burst was affected by heating temperature, drug/albumin concentration ratio and size distribution. After drug release test, the morphology of albumin micropheres was not changed. Albumin microsphere matrix was degraded by the rabbit liver tissue homogenate and proteolytic enzyme. The degree of degradation was affected by heating temperature.

• 대한화장품학회지
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• 제24권1호
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• pp.113-126
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• 1998

Inner nutshell of Castanea crenata has been used as an anti-aging and anti-wrinkle agent from the ancient time in east Asia. In order to develop new anti-aging and anti-wrinkle, ethanolic extract of inner nutshell of Castanea crenata was prepared and various biological activities were evaluated. Cor-285 possessed potent tree radical scavenging activity in vitro compared to gallic acid. Cor-285 showed the preventive effect against UV-induced cytotoxicity of fibroblast at concentration of 25-250mg/ml. When Cor-285 was evaluated for its anti-allergic activity, it effectively inhibited histamine release from mast cells induced by compound 48/80. The inhibitory activity was stronger than that of glycyrrhizinate. Cor-285 also showed on vivo inhibition against delayed hypersensitivity as well as croton-oil induced ear edema in mice when topically applied. These results strongly suggest that Cor-285 may reduce immunoregulatory/inflammatory skin trouble. From the attempts to isolate the scavenger, were isolated. In a clinical trial of twenty healthy volunteers with aged skin, 6 weeks application of Cor-285 decreased wrinkle about 26% and increased moisturizing 20% on the skin. All of these results indicate that Cor-285 may be an effective anti-aging and anti-wrinkle agent.

• 약학회지
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• 제41권3호
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• pp.305-311
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• 1997

Sustained release-microspheres and immediate release-pellets were prepared to develop a controlled release multiparticulate system containing both water soluble and insoluble dr ug. Pseudoephedrin.HCl (EPD) and terfenadine (TRF) were used as model drugs, respectively. Sustained release-EPD microspheres were prepared by solvent evaporation method using Eudragit RL or RS as a matrix combined with pH-insensitive film coating. Smaller EPD microspheres were obtained when smaller amount of Eudragit as a matrix material or larger amount of magnesium stearate as a dispersing agent was used. However the obtained microspheres did not show syfficient sustained release characteristics. About 97% of EPD was released after 1 hr irrespective of matrix material used. Subsequent coating of the microspheres with pH-insensitive polymer such as Eudragit RS or ethylcelulose (EC) resulted good sustained in 37.5, 73.3 and 92.0% release of encapsulated EPD in distilled water after 1, 3 abd 7 hr, respectively. It corresponds to mean dissolution time (MDT) of 2.3 hr, which is much larger than that of un-coated EPD microspheres (0.0048 hr). Immediate release TRF pellets were prepared by spherically agglomerated crystallization using Eudragit E as an inert matrix and methylene chloride as a liquid binder. Using Eudragit E alone as a matrix resulted in satisfactory physical properties of the pellets such as sphericity, surface texture and flowability, but led to slower release of TRF from pellets than un-modified TRF powder (MDT of 1.70 vs 1.43 hr in pH 1.2 dissolution medium). Introducing propylene glycol or sodium lauryl sulfate as an emulsifier brought about faster release of TRF from pellets (MDT of 1.14 and 0.95 hr, respectively). In conclusion, microencapsulation by solvent evaporation combined with film coating and spherically agglomerated crystallization were successfully utilized to prepare controlled release multiparticulate system composed of sustained release EPD-microspheres and immediate release TRF pellets.

• Journal of Animal Science and Technology
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• 제63권1호
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• pp.114-124
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• 2021

The objective of this study was to characterize the enzymatic hydrolysis of lipopolysaccharide (LPS) by wheat phytase and to investigate the effects of wheat phytase-treated LPS on in vitro toxicity, cell viability and release of a pro-inflammatory cytokine, interleukin (IL)-8 by target cells compared with the intact LPS. The phosphatase activity of wheat phytase towards LPS was investigated in the presence or absence of inhibitors such as L-phenylalanine and L-homoarginine. In vitro toxicity of LPS hydrolyzed with wheat phytase in comparison to intact LPS was assessed. Cell viability in human aortic endothelial (HAE) cells exposed to LPS treated with wheat phytase in comparison to intact LPS was measured. The release of IL-8 in human intestinal epithelial cell line, HT-29 cells applied to LPS treated with wheat phytase in comparison to intact LPS was assayed. Wheat phytase hydrolyzed LPS, resulting in a significant release of inorganic phosphate for 1 h (p < 0.05). Furthermore, the degradation of LPS by wheat phytase was nearly unaffected by the addition of L-phenylalanine, the inhibitor of tissue-specific alkaline phosphatase or L-homoarginine, the inhibitor of tissue-non-specific alkaline phosphatase. Wheat phytase effectively reduced the in vitro toxicity of LPS, resulting in a retention of 63% and 54% of its initial toxicity after 1-3 h of the enzyme reaction, respectively (p < 0.05). Intact LPS decreased the cell viability of HAE cells. However, LPS dephosphorylated by wheat phytase counteracted the inhibitory effect on cell viability. LPS treated with wheat phytase decreased IL-8 secretion from intestinal epithelial cell line, HT-29 cell to 14% (p < 0.05) when compared with intact LPS. In conclusion, wheat phytase is a potential therapeutic candidate and prophylactic agent for control of infections induced by pathogenic Gram-negative bacteria and associated LPS-mediated inflammatory diseases in animal husbandry.

• 공업화학
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• 제32권3호
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• pp.299-304
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• 2021

본 연구에서는 mung bean starch (MBS), polyvinyl alcohol (PVA), sodium benzoate (S), glycerol (GL), melanin (MEL)을 이용하여 광열 효과가 있는 기능성 acetaminophen (AP) 각인 MBS 기반 바이오 소재를 제조하고 약물 방출 특성을 조사하였다. 제조된 AP 각인 바이오 소재의 물리화학적 특성은 FE-SEM과 FT-IR을 통해 분석하였다. 또한, NIR (near infrared) laser (1.5 W/cm²) 조사에 따른 기능성 바이오 소재의 광열 효과 및 AP 방출 특성을 조사하였다. 바이오 소재에 NIR laser를 조사하였을 때, MEL이 첨가 바이오 소재는 첨가하지 않은 바이오 소재보다 2배 이상 높은 온도상승을 보였다. 표준 버퍼 용액과 인공 피부를 사용하여 기능성 AP 각인 바이오 소재의 AP 방출 특성 조사결과, NIR laser를 조사하였을 때, MEL 첨가 바이오 소재는 첨가하지 않은 바이오 소재보다 AP 방출율이 1.2배 높은 것을 확인하였다. 이 결과로부터, 기능성 바이오 소재는 급성 진통 치료를 위한 바이오 소재로 활용될 수 있을 것으로 판단된다.

• 한국정보통신학회논문지
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• 제16권7호
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• pp.1567-1574
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• 2012

이동에이전트의 노드 이주 방법은 분산 시스템의 전체 성능에 큰 영향을 줄 수 있는 요소가 되므로, 이러한 이동 에이전트의 센서 네트워크 내에서의 효율적 이주를 위한 방법이 요구되며, 이를 위하여 다양한 센서 네트워크 구성요소들(서버, 싱크 및 센서노드들) 관련 데이터들을 수집 및 저장하여 일관된 네이밍 서비스를 제공해야 할 필요가 있다. 따라서 본 논문에서는 센서데이터 서버의 정보가 저장되는 MetaData와 싱크노드들과 그들에 연결되어있는 센서노드들의 다양한 정보가 저장되는 SubMetaData 부분으로 나누어 메타테이블을 설계 구현하고, 이러한 메타테이블의 정보들을 이용한 RMI 기반의 네이밍 기법을 적용하여 능동규칙 이동에이전트의 정 방향 이주 방법을 구현함으로써 효율적인 센서 네트워크 응용 환경 구축 가능성을 제시하였다. 또한, 본 논문에서는 네이밍 에이전트를 J2EE 모델 기반의 RMI-IIOP(Internet Inter-ORB Protocol) 기술을 적용하여 설계 및 구현함으로써, 새로운 센서 네트워크 환경에 적합한 등록, 해제 및 검색 등을 수행할 수 있도록 하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제1권3호
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• pp.225-231
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• 1997

As it has been reported that the depolarization-induced norepinephrine (NE) release is modulated by activation of presynaptic $A_1-adenosine$ heteroreceptor and various lines of evidence indicate the involvement of adenylate cyclase system in $A_1-adenosine$ post-receptor mechanism in hippocampus, it was attempted to delineate the role of adenylate cyclase system in the $A_1-receptor-mediated$ control of NE release in this study. Slices from rat hippocampus were equilibrated with $[^3H]-NE$ and the release of the labelled products was evoked by electrical stimulation.(3 Hz, $5Vcm^{-1}$, 2 ms, rectangular pulses). The influence of various agents on the evoked tritium-outflow was investigated. $N^6-Cyclopentyladenosine$ (CPA), a specific $A_1-adenosine$ receptor agonist, in concentrations Tanging from 0.1 to $10{\mu}M$ decreased the $[^3H]-NE$ release in a dose-dependent mauler without any change of basal rate of release. 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX, $2{\mu}M$), a selective $A_1-receptor$ antagonist, inhibited the CPA effect. The responses to N-ethylmaleimide $(3&10{\mu}M)$, a SH-alkylating agent of G-protein, were characterized by increments of the evoked NE-release and the CPA effects were completely abolished by NEM pretreatment. Forskolin, a specific adenylate cyclase activator, in concentrations ranging from 0.1 to $30{\mu}M$ increased the evoked and basal rate of NE release in a dose-dependent manner and the CPA effects were inhibited by forskolin pretreatment. Rolipram $(1&10{\mu}M)$, a phosphodiesterase inhibitor, did not affect the evoked NE release but reduced the CPA effect. And 8-bromo-cAMP $(100&300{\mu}M)$, a membrane permeable cAMP analogue inhibited the CPA effect significantly. These results suggest that the $A_1-adenosine$ heteroreceptor plays an important role in NE-release via nucleotide-binding protein $G_i$ in the rat hippocampus and that the adenylate cyclase system might be participated in this process.

• Journal of Pharmaceutical Investigation
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• 제39권1호
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• pp.59-63
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• 2009

Soybean phosphatidylcholine microparticles loaded with cyclosporin A (CsA) were prepared by the modified emulsion solvent diffusion and ionic gelation method, in which chitosan on the surface of the microparticles was crosslinked with various concentrations of tripolyphosphate (TPP). The morphology of the particles was characterized by scanning electron microscopy (SEM). The change of particle size and zeta-potential by chitosan on the surface of the lipid microparticles were systematically observed. The encapsulation efficiency and loading capacity of CsA in the particles were determined by high performance liquid chromatography (HPLC). In vitro release kinetics was studied using the dialysis method. In the results, the mean particle size and the zeta-potential of lipid microparticles increased when the attached chitosan was cross-linked (from 2.5 to 6.2 ${\mu}m$ and from -37.0 to +93.0 mV, respectively). The cyclosporin A-loaded lipid microparticles appeared discrete and spherical particles with smooth surfaces. The encapsulation efficiency of CsA was between 79% and 90% while the loading capacity was between 41% and 56%. In vitro release study showed that the crosslinkage of chitosan by TPP significantly delayed the release of CsA from the particles in a concentration-dependent manner. Thus, the release of CsA from the lipid microparticles could be controlled by tripolyphosphate used as a cross-linking agent.

• 약학회지
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• 제36권3호
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• pp.212-219
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• 1992

Although oral route is the most convenient route for drug administration, the short and variable transit of drug through GI tract restricts the sustained drug absorption after oral administration. Thus, for sustained absorption of drugs, it is desirable to prolong the GI transit time by retaining the dosage forms in the stomach. In this study, the enzyme-digestible swelling hydrogel was synthesized by heating the mixed solution of N-vinyl-2-pyrrolidone[monomer], acrylated albumin[crosslinking agent] and proxyphylline[drug] at $65^{\circ}C$ for 10 hours in the cylindrical test tube. The resultant hydrogel tablet (diameter; 0.77 cm, thickness; 0.47 cm) was designed to swell in the gastric fluid after oral administration to such a size that passing through the pylorus could be inhibited during the drug release. After releasing drug, the hydrogel was expected to be degraded by pepsin, an enzyme in the stomach, and eventually solubilized. Actually, the hydrogel synthesized in the study swelled to a size larger than the diameter of the pylorus ($1.3{\pm}0.7$ cm) and slowly digested in the presence of pepsin. Drug release from the hydrogel was prolonged up to about 12 hours. The swelling kinetics was dependent on albumin acrylation time, drug content and gel thickness. Particularly the gel thickness was the most important factor that influences on drug release. By adjusting these factors, the albumin-crosslinked hydrogel was expected to be retained in the stomach for up to 60 hours and used as a potential platform of drugs for long-term GI absorption.