ビスベンゾチエニルエテンのフォトクロミズムに関する研究

第1章 序論 第2章 高繰り返し耐久性ビスベンゾチエニルエテン 第3章 ジナフチルエテン閉環体の熱安定性 第4章 黄色に着色するジチエニルエテン 第5章 ジチエニルエテンの置換基効果-吸光係数の増大- 第6章 鍵機構をもつビスベンゾチエニルエテン 第7章 総括Made available in DSpace on 2012-09-06T02:19:46Z (GMT). No. of bitstreams: 2 uchida1.pdf: 10605977 bytes, checksum: 59c29e8f340ee23bd3ae3928bb62216e (MD5) uchida2.pdf: 12937363 bytes, checksum: d7a0e2f9a303ebb7c7491e8a76b7e32a (MD5) Previous issue date: 1996-03-2

Object Transportation System Mimicking the Cilia of Paramecium aurelia Making Use of the Light-Controllable Crystal Bending Behavior of a Photochromic Diarylethene

The design of an object transportation system exploiting the bending behavior of surface-assembled diarylethene crystals is reported. A photoactuated smart surface based on this system can transport polystyrene beads to a desired area depending on the direction of the incident light. Two main challenges were addressed to accomplish directional motion along a surface: first, the preparation of crystals whose bending behavior depends on the direction of incident light; second, the preparation of a film on which these photochromic crystal plates are aligned. Nuclei generation and nuclear growth engineering were achieved by using a roughness-controlled dotted microstructured substrate. This system demonstrates how to achieve a mechanical function as shown by remote-controlled motion along a surface

Photoinduced swing of a diarylethene thin broad sword shaped crystal:a study on the detailed mechanism

We report a swinging motion of photochromic thin broad sword shaped crystals upon continuous irradiation with UV light. By contrast in thick crystals, photosalient phenomena were observed. The bending and swinging mechanisms are in fact due to molecular size changes as well as phase transitions. The first slight bending away from the light source is due to photocyclization-induced surface expansion, and the second dramatic bending toward UV incidence is due to single-crystal-to-single-crystal (SCSC) phase transition from the original phase I to phase IIUV. Upon visible light irradiation, the crystal returned to phase I. A similar SCSC phase transition with a similar volume decrease occurred by lowering the temperature (phase IIItemp). For both photoinduced and thermal SCSC phase transitions, the symmetry of the unit cell is lowered; in phase IIUV the twisting angle of disordered phenyl groups is different between two adjacent molecules, while in phase IIItemp, the population of the phenyl rotamer is different between adjacent molecules. In the case of phase IIUV, we found thickness dependent photosalient phenomena. The thin broad sword shaped crystals with a 3 mu m thickness showed no photosalient phenomena, whereas photoinduced SCSC phase transition occurred. In contrast, large crystals of several tens of mu m thickness showed photosalient phenomena on the irradiated surface where SCSC phase transition occurred. The results indicated that the accumulated strain, between isomerized and non-isomerized layers, gave rise to the photosalient phenomenon

Potential Energy Surfaces and Quantum Yields for Photochromic Diarylethene Reactions

molecule

Deposition transfection technology using a DNA complex with a thermoresponsive cationic Branched polymer

A novel non-viral gene transfection method in which DNA complexes were kept in contact with a deposition surface (deposition transfection) was developed. We designed a novel aqueous thermoresponsive adsorbent material for DNA deposition, which was a star-shaped copolymer with 4-branched chains. Each chain is comprised of a cationic poly(N,N-dimethylaminopropyl acrylamide) (PDMAPAAm) block (Mn: ca. 3000 g center dot mol(-1)), which formed an inner domain for DNA binding and a thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) block (Mn: ca. 6000 g center dot mol(-1)), which formed an outer domain for surface adsorption. Complex formation between the copolymer and the luciferase-encoding plasmid DNA occurred immediately upon simple mixing in an aqueous medium; polyplexes approximately 100 nm in size were formed. Because the lower critical solution temperature of the polyplexes was approximately 35 degrees C, they could deposit on the substrate by precipitation from an aqueous solution upon warming, which was confirmed by quartz crystal microbalance (QCM) method and water contact angle measurement. When COS-I cells were cultured on the polyplex-deposited substrate in a culture medium, the luciferase activity observed was higher than that observed on a DNA-coated substrate with or without the cationic polymer before and after complete adhesion and by conventional solution transfection using the polyplexes. The activity was enhanced with an increase in the charge ratio (surfactant/pDNA) with permissible cellular cytotoxicity. (c) 2007 Elsevier B.V. All rights reserved