낭성, 부분적으로 분화된 신아세포종 -1증례 보고

강신광,지제근,함의근 대한병리학회 1980 Journal of Pathology and Translational Medicine Vol.14 No.4

Tyrosol attenuates lipopolysaccharide-induced acute lung injury by inhibiting the inflammatory response and maintaining the alveolar capillary barrier

Kim, Y.Y.,Lee, S.,Kim, M.J.,Kang, B.C.,Dhakal, H.,Choi, Y.A.,Park, P.H.,Choi, H.,Shin, T.Y.,Choi, H.G.,Kwon, T.K.,Khang, D.,Kim, S.H. Pergamon 2017 Food and Chemical Toxicology Vol. No.

Acute lung injury (ALI) is a life-threatening disease characterized by increased pulmonary vascular permeability because of alveolar capillary barrier dysfunction and increased immune responses. This study determined the anti-inflammatory effect of tyrosol on lipopolysaccharide (LPS)-induced ALI and its underlying mechanisms of action. BALB/c mice were orally administered with tyrosol (0.1, 1, and 10 mg/kg) 1 h before an intratracheal injection of LPS (25 μg/50 μL). Oral treatment with tyrosol inhibited lung vascular permeability, histopathological changes, wet/dry lung weight ratio, and pulmonary vascular cell infiltration. The LPS-induced imbalance in the activity of enzymes, such as superoxide dismutase and myeloperoxidase, was regulated by tyrosol. Pro-inflammatory cytokines, such as tumor necrosis factor-α, interleukin (IL)-1β, and IL-6, were reduced by tyrosol in bronchoalveolar lavage fluid and lung tissue. The activation of inflammatory molecules, including inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, and phosphorylated-IκBα, was suppressed by the presence of tyrosol in the lung tissue. In addition, tyrosol attenuated the production of NO, the expression of pro-inflammatory cytokines, the expression of iNOS and COX-2, and the nuclear translocation of nuclear factor-κB in LPS-stimulated RAW 264.7 macrophages. These results suggested that tyrosol is a potential therapeutic agent for treating inflammatory lung diseases.

Biological evaluation of intervertebral disc cells in different formulations of gellan gum-based hydrogels

Khang, G.,Lee, S.K.,Kim, H.N.,Silva-Correia, J.,Gomes, M.E.,Viegas, C.A.A.,Dias, I.R.,Oliveira, J.M.,Reis, R.L. WILEY 2015 JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MED Vol.9 No.3

측정전극의 간격이 감각신경신호의 파라미터에 미치는 영향 연구

이강토(G. T. Lee),황선희(S. H. Hwang),배태수(T. S. Bae),박상혁(S. H. Park),강곤(G. Khang),송동진(T. Song) 한국정밀공학회 2013 한국정밀공학회 학술발표대회 논문집 Vol.2013 No.5월

Experimental investigation on the mechanical buckling of one-dimensional Si nanoribbons with a thickness contrast

Yoon, T.G.,Jiang, H.,Khang, D.Y. Elsevier Sequoia 2017 THIN SOLID FILMS - Vol.640 No.-

The mechanical buckling of one-dimensional Si nanoribbons with a thickness contrast was investigated. For Si stripes with a small thickness difference, each section was found to undergo its own buckling with characteristic wavelengths and wave amplitudes, depending on their thicknesses. On the other hand, unusual buckling occurred for Si ribbons with large thickness differences. For this case, the thinned sections were uniformly buckled, and absorbed a large portion of externally applied strain. On the contrary, the thicker parts of the ribbon were buckled nonuniformly, i.e. buckling occurred in central regions only, with an almost flat configuration at both ends of the thicker parts. Buckling mechanics can qualitatively explain the observed buckling of the Si ribbons with a small thickness contrast, while the finite length effect should be considered for the case of the Si ribbons with a large thickness contrast. Considering the fact that real functional devices are not uniform in thickness, the present work helps to understand the complex buckling behavior of mechanical systems with a wide range of thickness contrasts.

High-performance light diffuser films by hierarchical buckling-based surface texturing combined with internal pores generated from physical gelation induced phase separation of binary polymer solution

Park, H.G.,Khang, D.Y. IPC Science and Technology Press 2016 Polymer Vol.99 No.-

A simple and low-cost process has been demonstrated for the fabrication of high-performance light diffuser films. Instead of polymer composites with light diffusing micro/nanoparticles as in typical approaches, low refractive-index (RI) air pockets or pores have been included inside the diffuser film, which has large RI contrast to host polymer matrix. The generation of such pores has been enabled by elastomeric polydimethylsiloxane (PDMS) assisted fast drying of binary polymer solution, where physical gelation induced phase separation generates pores inside the dried film. To further increase the light scattering and thus the optical haze of such diffuser films, hierarchical buckling of PDMS surface by oxygen plasma treatment has been applied. The buckled PDMS could be directly integrated into the PDMS-assisted drying process, thereby enables one to fabricate high-performance diffuser films having both surface-relief patterns and internal pores at the same time. This unique combination of surface and volume scatterings has yielded high-performance light diffusing films with high transmittance and haze simultaneously.

Asymmetric porous membranes from binary polymer solution by physical gelation induced phase separation

Park, H.G.,Khang, D.Y. IPC Science and Technology Press 2016 Polymer Vol.87 No.-

Phase separation induced by physical gelation has been identified, based on systematic experimental data, as the mechanism responsible for the generation of porous structures in elastomeric polydimethylsiloxane (PDMS) assisted drying of binary polymer solution. Comparative experiments of natural drying have enabled one to clarify the similarities and differences in those different drying processes. Based on experimental observations, qualitative explanatory drying models have been suggested for those drying processes. Slow, equilibrated solvent removal in natural drying has led to the formation of gel-phase skin, and this gel-phase skin undergoes wrinkling instability due to large volume shrinkage. The gelation-induced phase separation has occurred at the very last stage of natural drying, leading to nanoscale pores in very thin bottom-most layer. On the other hand, rapid, instantaneous absorption of solvent into PDMS in PDMS-assisted drying has yielded glassy skin at the initial stage of drying. Then the underlying, trapped solution has been separated, induced by physical gelation, into solvent-rich sub-phases embedded into polymer-rich matrix, leading finally to microporous support layer in asymmetric polymeric membrane structure. Physical gelation-induced phase separation, ahead of vitrification of amorphous polymer, has been found to be the responsible mechanism for the generation of porous structure in elastomeric PDMS-assisted drying process. The elucidated phase separation mechanism involved in PDMS-assisted drying, when combined with quantitative kinetic models for drying processes, can pave the way for the fabrication of asymmetric polymeric membranes using other amorphous polymers.

Rapid effect of TBT upon fish liver hepatocytes

Dmitry L. Aminin,Irina G. Agafonova,Jae Ryoung Oh,Sung-Hyun Khang,Soo-Hyung Lee 한국해양환경·에너지학회 1999 한국해양환경·에너지학회 학술대회논문집 Vol.1999 No.-

Kinematic Analysis of a Mastication Model Employing the 6-DOF Parallel Mechanism

강곤,츠츠미 사다미,Khang, G.,Tsutsumi, Sadami The Korea Society of Medical and Biological Engine 1999 의공학회지 Vol.20 No.4

본 연구에서는 사람의 턱 운동과 턱 사이에 작용하는 힘(혹은 압력)을 그대로 나타낼 수 있는 저작로봇을 개발하는 것을 궁극적인 목표로 한다. 이러한 저작로봇이 개발되면, 치과의사가 환자의 턱운동에 나타나는 병변을 진단하고 치료하는데 큰 도움이 될 것으로 사료된다. 또한 , 본 연구에 채택한 병렬기구(parallel mechanism)에대한 순기구학적( forward kinematics)분석은 일반적인 병렬기구의 실계에도 응용될 것으로 기대된다. 본 연구진이 1차적으로 설계한 모델은 베이스와 플랫폼(platform), 그리고 이 둘을 연결하는 3개의 다리로 구성되어 있다. 다리와 플랫폼은 3자유도의 관절로 다리와 베이스는 1자유도의 경첩 관절로 연결되어 있으며, 이 3개의 경첩 관절은 베이스 위의 수평면에서 직선을 따라 움직인다. 경첩 관절의 수평 변위와 세 다리의 길이가 주어졌을 때 플랫폼의 위치와 오리엔테이션을 구하는 순기구학의 해( 解)를 계산해내는 알고리즘을 개발하였다. 이 알고리즘의 특징은 매 순간 오차를 계산하여 이 오차가 줄어드는 방향으로 나아가도록 시간간격(time step)을 조절하는 것이다. 본 알고리즘은 현재 가장 보편적으로 사용되고 있는 뉴튼-렙슨 방법에 비하여 3가지 장점을 나타내고 있다. 우선 , 초기치(initial guess)에 관계없이 수렴한다는 것이다. 또한, 본 알고리즘은 뉴튼-렙슨 방법에 비하여 수렴속도가 훨씬 빠르며, 연산 시간이 매우 짧아져 실제적인 실시간 적용에 적합하다. 마지막으로, 뉴튼-렙슨 방법에서는 여러 개의 해 가운데 어느 곳으로 수렴할 지 예측 할수 없으나 본 알고리즘에서는 초기치에 가장 가까운 해로 수렴한다. 이러한 순기구학의 다중성(multiplicity)문제를 해결하기 위하여 두 개의 조건을 제시하였으며, 이를 적용한 시뮬레이션 결과에 의하면 항상 원하는 해(true solution)에 수렴할 수 있었다.발생량의 감소를 기대 할 수 있는 친환경기술로 유지관리비를 최소화할 수 있는 장점이 있었다. 않은 사람들 중 미래의 검진실행의지에 건강소식지가 영향을 미친 경우는 48.7%였다. 보건교육을 받은 후 유방암 자가검진 실천율은 사업군에서 53.9%로 받기 전의 27.3%보다 증가하였으나 대조군의 경우는 별 차이가 없었다. 연령별로는 60대가 가장 높았고 사업군에서 검진율의 증가분은 30대가 가장 컸다. 교육수준별로는 사업군은 고졸이, 대조군은 전문대졸이 가장 높았고 사업군에서 검진율의 증가분은 고졸에서 가장 컸다. 보건교육 후 유방암과 관련된 건강지식의 정도는 사업군이 3.7점으로 대조군보다 유의하게 높았으며, 유방암 자가검진법을 실천하는 사람들의 동기는 ‘일반 대중매체의 영향’이 가장 많았으며 건강소식지가 동기인 경우도 20.4%였다. 사업군에서 건강소식지가 유방암 자가검진법 실천에 영향을 미친 경우가 79.6%였으며 유방암 자가검진법에 관한 보건교육을 받고 실천하지 않은 사람들 중 미래의 실천의지에 건강소식지가 영향을 미친 경우는 43.6%였다. 이상의 소견에서 지역주민을 대상으로 인쇄매체를 통한 보건교육은 인쇄물만으로도 쉽게 실천 할 수 있는 유방암 자가검진법이 가장 효과적이었으며, 자궁암검진에 관해서도 검진을 받을 수 있도록 지역사회의 보건의료의 하부구조를 정비하여 제도적 장치를 마련하고 정보를 제공한다면 자궁암검진 실천율도 증가할 것이다.고 12.9% 의 발달율을 보여 유의적인 차이를 보이지 않았다. 이상의 결과로 보아 핵이식

Hot filament chemical vapour deposition processing of titanate nanotube coatings

Godbole, V P,Kim, G S,Dar, M A,Kim, Y S,Seo, H K,Khang, G,Shin, H S IOP Pub 2005 Nanotechnology Vol.16 No.8

<P>In the present paper, we report on the processing of titanate nanotubes using the hot filament chemical vapour deposition (HF-CVD) method to synthesize titania–carbon nanotube–wire composites. The titanate nanotubes are prepared using a chemical route, and then deposited on <img SRC='http://ej.iop.org/images/0957-4484/16/8/035/nano197486ieqn1.gif' ALIGN='MIDDLE' ALT='\langle 100\rangle '/> silicon using an electrodeposition method. The HF-CVD is used to process these coatings at different temperatures in vacuum as well as in different concentrations of hydrogen (H<SUB>2</SUB>) and methane (CH<SUB>4</SUB>) gas mixtures. The evolutions of the surface and precipitation for various phases have been monitored using different characterization techniques. It is observed that titanate nanotubes start disintegrating above <I>T</I><SUB>s</SUB>∼500 ?C, and exhibit different types of phase precipitation depending upon the temperature and gas ambient. Under appropriate conditions, the presence of activated hydrogen and carbon radicals leads to the formation of novel architectures of mixtures of nanophases such as carbide, nonstoichiometric titania, carbon nanotubes, and titania decorated carbon nanowires. The results are discussed in terms of reduction in the thermal reaction barrier due to the presence of atomic hydrogen, and the formation of energetic sites during disintegration of titania nanotubes to facilitate nucleation of nanotube and nanowire structures.</P>