• 멤브레인
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• 제27권6호
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• pp.511-518
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• 2017

막유화(membrane emulsification, ME)는 SPG 막과 같이 균일한 크기의 세공을 갖는 막을 사용하여 좁은 입도분포의 에멀젼을 제조하는 기술이다. 본 연구에서는 막유화법으로 형성시킨 다중 에멀젼을 사용하여 폴리카프로락톤(PCL) 마이크로캡슐의 제조를 연구하였다. 먼저 초음파 유화기로 $W_1/O$ 단일 에멀젼을 제조한 후, premix 막유화를 적용하여 $W_1/O/W_2$ 다중 에멀젼을 형성시킨 후 용매 증발을 통해 모델 약물인 BSA가 담지된 PCL 마이크로캡슐을 제조하였다. 연속상에 대한 분산상의 비율(D/C ratio), PCL 농도, 유화제 농도, 모델 약물의 농도, 막간 압력차 등 막유화 변수가 제조된 마이크로캡슐의 입경과 입도 분포에 미치는 영향을 실험하였다. Premix-ME를 적용하여 평균 입경 $5{\sim}6{\mu}m$의 균일한 크기를 갖는 모델 약물 BSA의 함침량이 약 26%인 다중 코어형 PCL 마이크로캡슐을 제조할 수 있었다.

• 대한기계학회논문집A
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• 제38권4호
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• pp.371-377
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• 2014

조직 공학에 있어 인공지지체는 손상된 조직 및 기관의 기능을 재생하기 위한 거푸집으로 제공되며 3 차원 구조물이다. 인공지지체의 재료 중에서 폴리카프로락톤(Polycaprolactone, PCL)과 삼인산칼슘(${\beta}$-tricalcium phosphate, ${\beta}$-TCP)은 생분해성과 생체적합성을 가지고 있다. 본 연구에서는 다축 인공지지체 제작 시스템을 이용하여 3 차원 PCL, blended PCL(60 wt %)/${\beta}$-TCP(40 wt %), 그리고 ${\beta}$-TCP 인공지지체를 제작하였다. 제작된 인공지지체는 주사전자현미경 분석을 통해 $600{\pm}20{\mu}m$의 공극 크기로 잘 제작되었다. 기계적 특성 평가를 통해 3 차원 PCL, blended PCL(60 wt %)/${\beta}$-TCP(40 wt %), 그리고 ${\beta}$-TCP 인공지지체의 효과는 분석되었다. 게다가 Saos-2 세포를 이용한 in vitro 연구를 수행하여 세포 증착 및 증식과 같은 세포 거동에 의한 3 차원 인공지지체의 효과를 확인하였다. 요컨대 3D blended PCL(60 wt %)/${\beta}$-TCP(40 wt %) 인공지지체가 압축 강도와 생체적합성 그리고 골전도성에 있어서 인체의 해면골에 더욱 적합하였다. 따라서 3D 인공지지체의 제작에 있어 PCL과 ${\beta}$-TCP를 혼합하는 것은 효과적인 골 재생을 위해 촉망되는 전략이 될 것이다.

• 폴리머
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• 제38권2호
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• pp.150-155
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• 2014

Polycaprolactone(PCL)은 생분해성 고분자로 인장강도, 신장률, 충격강도 등의 기계적 물성이 우수하다. $TiO_2$ (titanium dioxide) nanoparticle은 친수성으로 밀도가 높고 생체적합성이 우수하다. 본 연구에서는 PCL과 $TiO_2$(titanium dioxide) nanoparticle을 이용하여 salt-leaching방법으로 3차원 다공성 지지체를 제작하였다. 제작한 지지체를 FESEM, FTIR, TGA, 압축강도 측정 등을 통해 물성을 분석하였다. $TiO_2$ nanoparticle에 의해 물흡수도와 팽윤도는 감소하였으나 압축강도는 증가하였다. CCK-8 assay를 통해 세포의 증식률을 확인한 결과, $TiO_2$ nanoparticle에 의한 세포 독성은 없는 것으로 확인되었다. 이러한 연구결과는 PCL/$TiO_2$ nanoparticle 지지체의 생체재료로 사용가능성을 제시하였다.

• 한국진공학회지
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• 제6권1호
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• pp.61-68
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• 1997

$In/PCI_3/H_2$계 chloride VPE법을 이용하여 반절연(semi-insulating) Fe-doped InP 기 판위에 undoped InP 에피층(epilayer) 성장시 중요한 변수인 성장온도와 $PCl_3/H_2$몰비가 에피층 성장에 미치는 영향을 조사하였다. 성장온도를 $620^{\circ}C$에서 $650^{\circ}C$까지 변화시켰고, $PCl_3/H_2$ 몰비는 $2.5{\times}10^{-2}$에서 4.5$\times$10-2까지 변화시켰다. 성장온도가 $640^{\circ}C$이고 $PCl_3/H_2$ 몰비가 $3.0{\times}10^{-2}$에서 표면결함이 최소가 되었고, $PCl_3/H_2$ 몰비가 증가할수록 표면결함이 증가하는 경향을 나타내었다. photoluminescence(PL), Hall, electrochemical capacitance-voltage(ECV) 측정을 통해 모든 undoped InP 에피층의 상온 이동자 농도가 $1{\times}10^{14}cm^{-3}$ 보다 이하인 것을 확인하였고, four point probe method를 이용하여 측정한 비저 항(resistivity)은 성장온도가 $640^{\circ}C$, PCl3/H2 몰비가 $3.0{\times}10^{-2}$에서 $3.0{\times}10^6{\Omega}\textrm{cm}$으로 가장 높 은 값을 보였다.

• Macromolecular Research
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• 제14권5호
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• pp.565-572
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• 2006

Recombinant human bone morphogenic protein-2 (rhBMP-2), which is known as one of the major local stimuli for osteogenic differentiation, was immobilized on the surface of hyaluronic acid (HA)-modified poly$(\varepsilon-caprolactone)$ (PCL) (HA-PCL) scaffolds to improve the attachment, proliferation, and differentiation of human bone marrow stem cells (hBMSCs) for bone tissue engineering. The rhBMP-2 proteins were directly immobilized onto the HA-modified PCL scaffolds by the chemical grafting the amine groups of proteins to carboxylic acid groups of HA. The amount of covalently bounded rhBMP-2 was measured to 1.6 pg/mg (rhBMP/HA-PCL scaffold) by using a sandwich enzyme-linked immunosorbant assay. The rhBMP-2 immobilized HA-modified-PCL scaffold exhibited the good colonization, by the newly differentiated osteoblasts, with a statistically significant increase of the rhBMP-2 release and alkaline phosphatase activity as compared with the control groups both PCL and HA-PCL scaffolds. We also found enhanced mineralization and elevated osteocalcin detection for the rhBMP-2 immobilized HA-PCL scaffolds, in vitro.

• Investigative Magnetic Resonance Imaging
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• 제25권2호
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• pp.93-100
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• 2021

Purpose: (1) To evaluate the trabecular pattern at the femoral attachment of the posterior cruciate ligament (PCL) in patients with a PCL injury; (2) to analyze bone microarchitecture by applying gray level co-occurrence matrix (GLCM)-based texture analysis; and (3) to determine if there is a significant relationship between bone microarchitecture and posterior instability. Materials and Methods: The study included 96 patients with PCL tears. Trabecular patterns were evaluated on T2-weighted MRI qualitatively, and were evaluated by GLCM texture analysis quantitatively. The grades of posterior drawer test (PDT) and the degrees of posterior displacement on stress radiographs were recorded. The 96 patients were classified into two groups: acute and chronic injury. And 27 patients with no PCL injury were enrolled for control. Pearson's correlation coefficient and one-way ANOVA with Bonferroni test were conducted for statistical analyses. This protocol was approved by the Institutional Review Board. Results: A thick and anisotropic trabecular bone pattern was apparent in normal or acute injury (n = 57/61;93.4%), but was not prominent in chronic injury and posterior instability (n = 31/35;88.6%). Grades of PDT and degrees of posterior displacement on stress radiograph were not correlated with texture parameters. However, the texture analysis parameters of chronic injury were significantly different from those of acute injury and control groups (P < 0.05). Conclusion: The trabecular pattern and texture analysis parameters are useful in predicting posterior instability in patients with PCL injury. Evaluation of the bone microarchitecture resulting from altered biomechanics could advance the understanding of PCL function and improve the detection of PCL injury.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.39.2-39.2
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• 2009

In this work, Poly($\varepsilon$-Caprolactone)(PCL) andpoly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV) mats were fabricated usingelectrospinning process. The electrospinning process is a simple and efficient method to fabricate the nanofibrous mats. PCL and PHBV is a kind of biodegradable polymer but their mechanical properties aren't good. For improving mechanical properties, PHBV mats were coated by TCP. Using PCL mats and TCP-coated PHBV composite mats, a bio-resorbablebone plate were made by pressing. Detailed micro-structural characterization was done by SEM techniques. Tensile strength and bending strength were also evaluated for mechanical properties. The cytotoxicity evaluation ofPCL/TCP-coated PHBV composite multilayer was done by MTT assay. The evidence obtained in this work implies the potential for use as a biodegradable boneplate.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.262-262
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• 2006

Biodegradable and amphiphilic di-block and tri-block copolymers, prepared with monomethoxy poly ethylene glycol (MPEG) and ${\varepsilon}-caprolactone\;({\varepsilon}-CL)$, were used for the application of W1/O/W2 multi- emulsion capsules. The effects of topology and the ratio of hydrophilic moiety of PCL-based polymers on the encapsulation efficiency of the $W_{1}/O/W_{2}$ multi-emulsion capsules containing Ascorbic Acid-2-Glucoside (AA-2-G) were investigated. The ratio of PEG and PCL was 1:0.5, 1:0.75, 1:1, and 1:1.25. PEG-PCL block copolymers were added to the first step of the preparation of $W_{1}/O$ emulsions. The dispersion stability, the particle size, the morphology of the $W_{1}/O/W_{2}$ multi-emulsion capsules were observed using an on-line turbidity meter, dynamic light scattering (DLS), a confocal microscopy (with FITC) and an optical microscopy. Biodegradable behavior of the PEG-PCL block copolymers and release behavior of AA-2-G were also observed by Gel Permeation Chromatography (GPC) and High Performance Liquid Chromatography (HPLC).

• 한국군사과학기술학회지
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• 제24권2호
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• pp.165-174
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• 2021

This study describes a method of measurement and verification of array manifold of uniform circular array antenna applicable to multistatic Passive Coherent Location(PCL) system using FM broadcasting. In an environment of outdoor test where FM broadcast signals are scattered, array manifold measurement methods using network analyzer and multi-channel digital receiver are introduced. Also, the descriptions and solutions for the test limits of each measurement method and the considerations affecting the measurement accuracy are presented. In addition, to verify the validity of the measured array manifold, the gain and phase difference were compared with the array manifold data obtained by EM simulation, and the effectiveness and accuracy of the measured array manifolds were compared and analyzed by estimating the direction of arrival of the FM broadcast signal received from the multistatic PCL system.

• 방사선산업학회지
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• 제5권2호
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• pp.107-112
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• 2011

Electron beam-induced crosslinking of polycaprolactone (PCL) films containing various crosslinking agents (CAs) was investigated in this study. PCL films containing various CAs prepared by a solution casting method were irradiated by electron beams at various absorption doses and the irradiated PCL films were investigated in terms of their crosslinking degree, thermal and mechanical properties, and biodegradability. Based on the results of the crosslinking degree measurement, triallyl isocyanurate was found to be most effective for the electron-beam induced crosslinking of PCL films. The results of the UTM, DMA, and TMA revealed that the thermal and mechanical properties of the crosslinked PCL films were greatly improved in comparison to those of the pure PCL. The results of the enzymatic degradation test revealed that the biodegradability of the crosslinked PCL films was reduced in comparison to that of the pure PCL.