• Journal of applied mathematics & informatics
• /
• 제15권1_2호
• /
• pp.485-493
• /
• 2004

This paper presents the interesting properties of a certain patterned matrix that plays an significant role in the statistical analysis. The necessary and sufficient condition on the existence of the inverse of the patterned matrix and its determinant are derived. In special cases of the patterned matrix, explicit formulas for its inverse, determinant and the characteristic equation are obtained.

• Communications for Statistical Applications and Methods
• /
• 제2권1호
• /
• pp.89-98
• /
• 1995

This paper presents the interesting properties of a certain patterned matrix that plays an significant role in the multi-way balanced designs. The necessary and sufficient condition on the existence of the inverse of the patterned matrix and its determinant are described. In special cases of the pattermed matrix, explicit formulas for its inverse, determinant and the characteristic equation are obtained.

• 대한의용생체공학회:의공학회지
• /
• 제40권1호
• /
• pp.1-6
• /
• 2019

Human mesenchymal stem cells (hMSC) are multipotent stromal cells that have great potential to differentiate into a variety of cell types such as osteocytes, chondrocytes, and myocytes. Although there have been many studies on their clinical availability, little is known about how intracellular signals can be modulated by topographic features of the extracellular matrix (ECM). In this study, we investigated whether and how microwavy-patterned extracellular matrix (ECM) could affect the signaling activity of focal adhesion kinase (FAK), a key cellular adhesion protein. The fluorescence resonance energy transfer (FRET)-based FAK biosensor-transfected cells are incubated on microwavy-patterned surfaces and then platelet derived growth factor (PDGF) are treated to trigger FAK signals, followed by monitoring through live-cell FRET imaging in real time. As a result, we report that PDGF-induced FAK was highly activated in cells cultured on microwavy-patterned surface with L or M type, while inhibited by H type-patterned surface. In further studies, PDGF-induced FAK signals are regulated by functional support of actin filaments, microtubules, myosin-related proteins, suggesting that PDGF-induced FAK signals in hMSC upon microwavy surfaces are dependent on cytoskeleton (CSK)-actomyosin networks. Thus, our findings not only provide new insight on molecular mechanisms on how FAK signals can be regulated by distinct topographical cues of the ECM, but also may offer advantages in potential applications for regenerative medicine and tissue engineering.

• Journal of Periodontal and Implant Science
• /
• 제47권6호
• /
• pp.402-415
• /
• 2017

Purpose: The aim of this study was to determine the effects of patterned human periodontal ligament stem cell (hPDLSC) sheets fabricated using a thermoresponsive substratum. Methods: In this study, we fabricated patterned hPDLSC sheets using nanotopographical cues to modulate the alignment of the cell sheet. Results: The hPDLSCs showed rapid monolayer formation on various surface pattern widths. Compared to cell sheets grown on flat surfaces, there were no significant differences in cell attachment and growth on the nanopatterned substratum. However, the patterned hPDLSC sheets showed higher periodontal ligamentogenesis-related gene expression in early stages than the unpatterned cell sheets. Conclusions: This experiment confirmed that patterned cell sheets provide flexibility in designing hPDLSC sheets, and that these stem cell sheets may be candidates for application in periodontal regenerative therapy.

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2011년도 춘계학술발표대회
• /
• pp.8.2-8.2
• /
• 2011

This talk demonstrates diverse patterned structures utilizing in-situ self-organization and phase separation of the materials into an ordered fashion. The patterned structures in this talk include electrospun nanofibers and electrosprayed microparticles embedding small particles. The positions of the small particles are in-situ controlled during the electrohydrodynamic process by the interaction with the polymer matrix. Another topic of the talk includes selective deposition of spin-coated materials on a corrugated surface that was prepared by buckling of polymer thin films. Solution are strong tendency to be positioned in the trench area of the surface, which facilitates the fabrication of micropatterns of diverse materials.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2012년도 추계학술대회 논문집
• /
• pp.343-344
• /
• 2012

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2003년도 생물공학의 동향(XII)
• /
• pp.643-643
• /
• 2003

• 한국광학회:학술대회논문집
• /
• 한국광학회 2008년도 동계학술발표회 논문집
• /
• pp.397-398
• /
• 2008

We have developed simplified processes for the formation of insulators, cathode separators and bus electrodes in PMOLEDs. The insulators and cathode separators are patterned simultaneously by a single layer of image reversal photoresist. And, the bus electrodes of low resistance are formed by the cathode separator and cathode metal. Using these simplified processes, we fabricated 1.17" $96{\times}RGB{\times}96$ panels and analyzed their performance and reliability.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.1455-1457
• /
• 2008

Cell adhesion is a coordinated process involving initial binding of integrin receptors to extracellular matrix (ECM), recruitment of adhesion proteins, and focal adhesion assembly. The formation of mechanically stable focal adhesion assembly of cells within surrounding ECM is a key parameter to direct numerous cellular functions including cell migration, differentiation, and apotosis. With current cell adhesion assays, it is difficult to understand contributions of each coordinated event on evolution of cell adhesion strengthening since cells spontaneously spread upon their adhesion to the substrate, thus remodeling their cytoskeletal structure. In this presentation, novel approaches for analysis of cell adhesion strengthening process based on the combination of mechanical device, micro-patterned substrates, and molecular biological techniques will be discussed.

• 한국진공학회지
• /
• 제16권5호
• /
• pp.366-370
• /
• 2007

밀도가 높고 주기적으로 배열된 나노 크기의 기공이 25nm 두께의 실리콘 산화막 기판위에 형성 되었다. 나노미터 크기의 패턴을 형성시키기 위해서 자기조립물질을 사용했으며 폴리스티렌(PS) 바탕에 벌집형태로 평행하게 배열된 실린더 모양의 폴리메틸메타아크릴레이트(PMMA)의 구조를 형성하였다. 폴리메틸메타아크릴레이트를 아세트산으로 제거하여 폴리스티렌만 남아있는 나노크기의 마스크를 만들었다. 폴리스티렌으로 이루어진 나노패턴의 지름은 $8{\sim}30nm$ 였고 높이는 40nm였으며, 패턴과 패턴사이의 간격은 60nm였다. 형성된 패턴을 실리콘 산화막 위에 전사시키기 위해 불소 기반의 화학 반응성 식각을 사용하였다. 실리콘 산화막에 형성된 기공의 지름은 $9{\sim}33nm$였다. 실리콘 산화막을 불산으로 제거하여 실리콘에 형성된 기공을 관찰하였고, 실리콘기판에 형성된 기공의 지름은 $6{\sim}22nm$였다. 형성된 기공의 크기는 폴리메틸메타아크릴레이트의 분자량과 관계가 있음을 알 수 있었다.