ABSTRACT
An extremely simple structural design of a composite material composed of an elastomer sheet and hard beads embedded at the surface is proposed to realize a shape-tunable surface; it reversibly forms bumps/undulations in response to in-plane tensile strain applied to the surface. Tribological properties such as adhesion therefore become switchable.
ABSTRACT
Wrinkling of a soft elastomer surface capped by a relatively hard thin film or modified by some physical treatments to induce hardening has been widely studied for applications in fields such as low-cost micro-fabrication, optics and tribology. Here we show that a biaxial textile sheet embedded on the surface of an elastomer buckles and selectively forms anisotropic wrinkles when experiencing a compressive strain in the fibre axial direction. The wrinkles also possess a fine surface structure that originates from the periodic structure of the biaxial textile sheet. Depending on whether the surface is wrinkled or not, the unique frictional property due to which the friction on wrinkles significantly decreases by a factor of less than 0.1 because of the localized contact regions on the protrusions originating from the textile structure is shown.
ABSTRACT
A new structural design is proposed for wrinkling to improve mechanical durability by exploiting a porous polymer film embedded on the surface of an elastomer, which acts as a hard layer, buckles into wrinkles and effectively suppresses fatal failures such as delamination and cracking.
ABSTRACT
The dewetting of a surfactant droplet, induced by the adsorption of surfactants on a hydrophilic glass substrate, was observed experimentally. After being dropped onto the substrate, the droplet began shrinking and the speed of shrinkage increases with the surfactant concentration. We explained this dynamics, which is known as reactive dewetting, semi-quantitatively by expanding a simple theoretical model originally proposed and discussed qualitatively by M. E. R. Shanahan and P.-G. de Gennes [Start-up of a reactive droplet, C. R. Acad. Sci. Paris, 1997, 324, 261-268]. In addition, for the surfactant droplet with a concentration near or higher than the critical micelle concentration (CMC), we found that it maintains a large final contact area compared with that in the case of the low surfactant concentration. We discussed this phenomenon by taking the decrease in the vapor-liquid and solid-liquid interfacial tensions into consideration.
ABSTRACT
Three double negative (BoCD4-, BoCD8-) bovine T cell lines, BTL-PC3, BLT2, and Pr2181, which have been established from bovine lymphosarcomas, were examined for expression and molecular function of bovine c-myb genes. BTL-PC3 expressed 4.0- and 3.6-kilobase c-myb transcripts, and BLT2 and Pr2181 expressed a 3.8-kilobase c-myb message. The c-Myb protein (75 kDa) was detected in Pr2181 but not as a clear band in BLT2, while BTL-PC3 exhibited a 65-kDa c-Myb band in immunoprecipitation tests with anti-Myb antiserum. Nucleotide sequences for c-myb cDNA clones from BTL-PC3 and BLT2 indicated that the predicted bovine wild-type c-Myb from BLT2 consists of 640 amino acids whereas that from BTL-PC3 consists of 555 amino acids lacking 85 internal amino acids. This deleted DNA region (255 base pairs consisting of 85 amino acids) corresponds to the human genomic exon 9 encoding a negative regulatory domain in the c-myb gene. Upon cotransfections with reporter plasmids containing myb binding sites, the internally deleted c-Myb exhibited a 3-fold higher transcriptional activity than the wild-type c-Myb in chloramphenicol acetyltransferase assays. These results indicate that internal DNA deletion in the c-myb gene is directly involved in the enhancement of transcriptional activation in bovine T lymphoma cells.
