• 대한기계학회논문집B
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• 제36권5호
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• pp.545-551
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• 2012

마이크로 유체구조를 기반으로 하는 약물전달장치는 마이크로 유체 채널형상의 간단한 변형만으로 약물분출량을 쉽게 조절할 수 있는 장점이 있다. 그러나 디바이스 제작에 사용된 생분해성 고분자 85/15poly(lactic-co-glycolic acid) (85/15PLGA)의 소수성 기질 때문에 약물전달 장치내부로의 release medium의 유입이 원활하게 이루어지지 않으며 그 결과, 디바이스의 임플랜트 후 초기의 약물 분출에 영향을 줄 것으로 예상된다. 따라서 surfactant인 polyethylene-glycol600 (PEG600)과 Tween80을 이용하여 micro-channel의 표면처리를 한 디바이스와 surfactant를 사용하지 않은 디바이스를 각각 제작하여 약물 전달 실험을 하였으며, 이를 바탕으로 마이크로 유체 채널의 기하학적 형상에 따른 국소 마취제의 일종인 bupivacaine HCl(BHCl)의 분출속도제어를 입증하였다.

• 한국작물학회지
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• 제32권1호
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• pp.61-66
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• 1987

삼투처리와 무처리의 대두종자(품종 :Williams)에 대하여 두가지 온도(15, 3$0^{\circ}C$)에서 두가지의 종자수분함량(30%, 50%)으로 조절된 조건으로 0. 2, 4 및 8일간 전처리함에 있어서 시간별 세세구배치법 4반복으로 배치하여 발아와 묘신장을 조사하였던 바 주요결과는 다음과 같다. 1. 콩의 묘신장은 30에서 2일간 전처리함으로서 촉진되었으나 같은 온도에서 전처리기간이 길수록 억제되었다. 2. 삼투처리후 전처리된 종자는 수분흡수와 묘신장이 떨어졌다. 3. 종자수분함량이 50%로 조절된 뒤 전처리된 것은 체의 수분함량을 증가시켰으며 4일간까지의 전처리는 묘신장을 크게 하였다. 4. 묘의 건물중에서는 전처리온도가 3$0^{\circ}C$ 일때와 종자수분함량이 50%로 조절되어 8일간 전처리하였을 때 감소되었다.

• Journal of Electrochemical Science and Technology
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• 제7권2호
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• pp.132-138
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• 2016

In this study, we report the fabrication of functional complex fibers, which have been studied widely globally for numerous applications. Here, we fabricated conductive complex fibers with antibacterial properties by coating metal ions on the surface of plastic (polypropylene) fibers using the electroless and electrochemical deposition. First, we polished the polypropylene melt-blown fiber surface and obtained an absorbing Pd seed layer on its surface. Subsequently, we substituted the Pd with Cu. Bis-3-sulfopropyl-disulfide disodium salt (SPS), polyethylene glycol (PEG), and ethylene thiourea (ETU) were used as the brightener, carrier, and leveler, respectively for the electroplating. We focused on most achieving the stable plating condition to remove dendrites, which are normally during electroplating metals so that smooth layer is formed on the fiber surface. The higher the amount of SPS, the higher was the extent of irregular plate-like growth. Many irregularities in the form of round spheres were observed with increase in the amount of PEG and ETU. Hence, when the additives were used separately, a uniform coating could not be obtained. A stable coating was obtained when the three additives were combined and a uniform 5-9 μm thick copper layer with a stable morphology could be obtained around the fiber. We believe that our results can be applied widely to obtain conductive fibers with antibacterial properties and are useful in aiding research on conductive lightweight composite fibers for application in information technology and robotics.

• Journal of the Korean Wood Science and Technology
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• 제27권2호
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• pp.1-6
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• 1999

1995년 충북대 선사문화연구소에 의해 평택시 안중면 현화리 토탄층에서 발굴된 수침고목재(약 2500년전) 63점을 연구대상으로 하였다. 수침고목재는 PEG 2000으로 포매한 후 로타리마이크로톰으로 박편을 제작하여 분석하였다. 대부분의 시료가 오랜 기간동안의 부후로 인하여 조직을 관찰할 수 없었기 때문에 비교적 상태가 양호한 27점만 수종을 식별할 수 있었다. 식별된 수종은 오리나무속(55.6%), 물푸레나무속(33.3%), 참나무속의 상수리나무아속(11.1%)으로 모두 활엽수종이었으며 침엽수종은 발견되지 않았다. 이들 수종의 구성으로 보아 연구지역이 마지막 빙하기이후 서해안 해수면 상승에 의해 형성된 습지나 효수 주변이었던 것으로 해석된다.

• Biomolecules & Therapeutics
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• 제16권4호
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• pp.425-430
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• 2008

The objectives of this study were to prepare PLGA film onto the surface of the capsular tension ring (CTR) for controlled drug release and investigate the influence of plasticizers, the test drug and measurement conditions on flexibility of the film. Film solutions were prepared by dissolving PLGA, plasticizer (triethyl citrate, TEC or polyethylene glycol, PEG), test drug (dexamethasone) in ethyl acetate then films were prepared by spray coating and evaporation method. Then, the flexibility of PLGA film was determined by elongation test. The addition of plasticizer, PEG or TEC to PLGA copolymer caused a depression of glass transition temperature ($T_g$) and the elasticity of PLGA films increased. The addition of dexamethasone to the PLGA/TEC matrix decreased the flexibility of film. Dimensional factors of the PLGA films such as width and thickness were significantly influenced on flexibility of films and film length and elongation speed had no considerable influence on elongation of films. In this study, sufficiently flexible and stable PLGA films capable of being coated onto CTR could be prepared. This PLGA films can be used as a platform for local drug delivery.

• Journal of Pharmaceutical Investigation
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• 제24권2호
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• pp.57-65
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• 1994

To increase the dissolution rate of practically insoluble biphenyl dimethyl dicarboxylate (DDB), various solid dispersions were prepared with water soluble carriers, such as povidone (PVP K-30), poloxamer 407, sodium deoxycholate (SDC) and polyethylene glycol (PEG) 6000, at drug to carrier ratios of 1:3, 1:5 and 1:10 (w/w) by solvent or fusion method. Dissolution test was performed by the paddle method. The dissolution rate of DDB tablets (25 mg) on market was found to be very low (11.44, 9.02 and 6.42% at pH 1.2, 4.0 and 6.5 after 120 min, respectively). However, dissolution rates of DDB from various solid dispersions were very fast and reached supersaturation within 10 min. DDB-PEG 6000 solid dispersion appeared to be better in enhancing the in vitro dissolution rate than others. Furthermore, the incorporation of DDB and phosphatidylcholine (PC) into ${\beta}-cyclodextrin$ at ratios of 1:2:20, 1:5:20 and 1:10:20 resulted in a 4.9-, 11.2- and 19.6-fold increase in DDB dissolution after 120 min as compared with the pure drug, respectively. This might be attributed to the formation of lipid vesicles which entrapped a certain concentration of DDB during dissolution. On the other hand, the permeation of DDB through rabbit duodenal mucosa was examined using some enhancers such as SDC, sod. glycocholate (SGC) and glycyrrhizic acid ammonium salt (GAA). Only trace amounts of DDB were found to permeate through deuodenal mucosa in the absence of enhancer. SDC was found to markedly decrease the permeation flux of DDB, however, SGC and GAA (5 mM) enhanced the flux of DDB 1.6 and 2.4 times higher as compared with no additive, respectively.

• Archives of Pharmacal Research
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• 제18권3호
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• pp.183-188
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• 1995

Polymeric reinforcement and coatings of alginate beads were carried out to control the release rate of drug from alginate beads. A poorly water-soluble ibuprofen (IPF) was selected as a model drug. A commercially available $Eudragit^{\circledR}$ RS100 was also used as a polymer. Effects of polymeric contents, the presence of plasticizers and amount of drug loading on the release rate of drug were investigated. The release rate of drug from alginate beads in the simulated gastric fluid did not occur within 2 h but released immediately when dissolution media were switched to the simulated intestinal fluid. No significant difference of release rate from polymer-reinforced alginate bead without plasticizers was observed when compared to plain (simple) beads. However, the release rate of drug from polymer-reinforced alginate beads was further sustained and retarded when aluminium tristearate (AT) as a plasticizer was added to polymer. However, polyethylene glycol 400 (PEG400) did not change the release rate of drug from alginate beads although PEG400 was used to improve dispersion of polymer and sodium alginate, and plasticize $Eudragit^{\circledR}$ RS100 polymer. The presence of plasticizer was crucial to reinforce alginate gel matrices using a polymer. As the amount of drug loading increased, the release rate of drug increased as a result of decreasing effects of polymer contents in matrices. The significantly sustained release of drug from polymer-coated alginate beads occurred as the amount of polymer increased because the thickness of coated membrane increased so that cracks and pores of the outer surface of alginate beads could be reduced. The sustained and retarded action of polymer-reinforced and coated beads may result from the disturbance of swelling and erosion (disintegration) of alginate beads. From these findings, polymeric-reinforcement and coatings of alginate gel beads can provide an advanced delivery system by retarding the release rate of various drugs.

• 한국재료학회지
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• 제22권7호
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• pp.335-341
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• 2012

Recently, the demand for the miniaturization of printed circuit boards has been increasing, as electronic devices have been sharply downsized. Conventional multi-layered PCBs are limited in terms their use with higher packaging densities. Therefore, a build-up process has been adopted as a new multi-layered PCB manufacturing process. In this process, via-holes are used to connect each conductive layer. After the connection of the interlayers created by electro copper plating, the via-holes are filled with a conductive paste. In this study, a desmear treatment, electroless plating and electroplating were carried out to investigate the optimum processing conditions for Cu via filling on a PCB. The desmear treatment involved swelling, etching, reduction, and an acid dip. A seed layer was formed on the via surface by electroless Cu plating. For Cu via filling, the electroplating of Cu from an acid sulfate bath containing typical additives such as PEG(polyethylene glycol), chloride ions, bis-(3-sodiumsulfopropyl disulfide) (SPS), and Janus Green B(JGB) was carried out. The desmear treatment clearly removes laser drilling residue and improves the surface roughness, which is necessary to ensure good adhesion of the Cu. A homogeneous and thick Cu seed layer was deposited on the samples after the desmear treatment. The 2,2'-Dipyridyl additive significantly improves the seed layer quality. SPS, PEG, and JGB additives are necessary to ensure defect-free bottom-up super filling.

• Advances in concrete construction
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• 제9권1호
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• pp.33-41
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• 2020

In this study, polyethylene glycol (PEG) and polyacrylamide (PAM) have been used as self-curing agents to produce self-curing concrete (SC). Compressive strength, ultrasonic pulse velocity (UPV), bulk electrical resistivity, chloride ion penetrability, water permeability, and main microstructural characteristics were examined under different curing regimes, and compared to those of the control concrete mixture with no self-curing agents. One batch of a control mixture and one batch of a SC mixture were air-cured in the lab to act as non-water-cured samples. The water curing regimes for the control mixture included continuous water curing for 3, 7, and 28 days and periodical moist curing using wetted burlap for 3 and 7 days. Curing regimes for the SC mixtures included 3 days of water curing and periodical moist curing for 3 and 7 days. SC mixtures showed better microstructure development and durability performance than those of the air-cured control mixture. A short water curing period of 3 days significantly improved the performance of the SC mixtures similar to that of the control mixture that was water cured for 28 days. SC concrete represents a step towards sustainable construction due to its lower water demand needed for curing and hence can preserve the limited water resources in many parts of the world.

• Advances in materials Research
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• 제3권4호
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• pp.233-242
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• 2014

Magnetic and conducting aniline sulfide resin cross-linked (ASC-Fe3O4) nanocomposite has been prepared in the presence of aniline sulfide resin (ASR), aniline, $Fe_3O_4$ coated by polyethylene glycol (PEG) and initiator. The magnetic properties of the resulting composites showed ferromagnetic behavior, such as high-saturated magnetization (Ms= 41 emu/g), and coercive force (Hc=1.5 Oe). The saturated magnetization was increased by increasing of $Fe_3O_4$ content and decreased by increasing aniline ratio. The transmission electron micrograph (TEM) and X-ray diffraction proved that nanometer-sized about 20-30 nm $Fe_3O_4$ in the composite. The average size of ASC-$Fe_3O_4$ nanocomposite with core-shell structure was about 50-60 nm, and polydisperse. This approach may also be extended to the synthesis and modification of other polymers. Electrical conductivity of aniline sulfide resin cross-linked (ASC) nanocomposite has been studied by four-point probe method and produced $3.3{\times}10^{-4}S/cm$ conductivity for it. The conductivity of the composites at room temperature depended on the $Fe_3O_4$, aniline ratio and doping degree. The thermogravimetry analysis (TGA) results showed that this resin is thermal resistance near of $500^{\circ}C$. So, It can be used for resistance thermal coating for military applications. $Fe_3O_4$-PASC nanocomposite has been flexible structure with electrical and magnetic properties.