A fibre actuator that generates a large strain with high specific power represents a promising strategy to develop novel wearable devices and robotics. We propose a new coiled-fibre actuator based on highly drawn, hard linear low-density polyethylene (LLDPE) fibres. Driven by resistance heating, the actuator can be operated at temperatures as low as 60 °C and uses only 20% of the power consumed by previously coiled fibre actuators when generating 20 MPa of stress at 10% strain. In this temperature range, 1600 W kg−1 of specific work (8 times that of a skeletal muscle) at 69 MPa of tensile stress (230 times that of a skeletal muscle) with a work efficiency of 2% is achieved. The actuator generates strain as high as 23% at 90 °C. Given the low driving temperature, the actuator can be combined with common fabrics or stretchable conductive elastomers without thermal degradation, allowing for easy use in wearable systems. Nanostructural analysis implies that the lamellar crystals in drawn LLDPE fibres are weakly bridged with each other, which allows for easy deformation into compact helical shapes via twisting and the generation of large strain with high work efficiency.

Aims-To determine the eVect of intact corneal epithelium on stromal haze and myofibroblast cell formation after excimer laser surgery. Methods-Denuded epithelium alone, photorefractive keratectomy (PRK), laser in situ keratomileusis (LASIK), or LASIK with denuded epithelium was performed in rabbit eyes. Postoperative anterior stromal haze was assessed employing a standard scale. Immunohistochemical methods were used to detect alpha smooth muscle actin ( -SMA), a marker for myofibroblastic cells, and type III collagen in subepithelial corneal tissue. Results-Three weeks after surgery, the presence of -SMA positive long extended and spindle-shaped stromal cells, and synthesis of type III collagen were observed in the subepithelial stromal layer corresponding to corneal haze in PRK and LASIK with denuded epithelium, but not in denuded epithelium alone and LASIK. Conclusion-The intact corneal epithelium may play an important part curbing subepithelial haze and diVerentiation of myofibroblasts in corneal wound healing. (Br J Ophthalmol 2001;85:209-213)

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After LASIK to correct myopia of greater than -6.0 D, there may be a persistent decrease in intermediate and low CVA. Patients should be informed preoperatively of this possible decrease in CVA.

The intact corneal epithelium might play an important role in curbing differentiation of myofibroblasts in corneal wound healing. Injured epithelial cells stimulate fibroblast myodifferentiation through one or more soluble factors, including TGF-beta.

Homogeneous surface alignment of liquid crystals (5CB) is observed for films formed by coating with aqueous solutions of hydroxypropylcellulose (HPC) for high coating speeds and thin coating thicknesses. On the other hand, for films formed with isotropic ethanol solutions of HPC, 5CB molecules retain the flow-induced alignment created at the formation of the 5CB droplet. The microstructures responsible for the homogeneous surface alignment are not confirmed in the morphological measurement of the film surface with an atomic force microscope, although large grooves corresponding to the banded texture perpendicular to the coating direction exist on the films formed with liquid crystalline solutions of HPC. The possibility of highly oriented HPC molecules in the coating flow is pointed out using the Doi model. These results suggest that the flow-induced anisotropic orientation of HPC molecules is responsible for the homogeneous surface alignment of 5CB.

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