Provided is a fiber for rubber reinforcement that can be produced using a bio-derived raw material and hardly breaks even when compounded with a rubber material. A first fiber for rubber reinforcement uses a protein fiber containing a hydrophobic protein. A second fiber for rubber reinforcement uses a protein fiber having an initial tensile modulus of elasticity of 2.0 GPa or more when wet. These fibers for rubber reinforcement preferably have a coating layer made of a water-based adhesive composition on the surface thereof.

An object of the present invention is to provide a method capable of producing a protein fiber in which shrinkage at the time of first contact with moisture after production is more reliably suppressed and generation of crimp is also suppressed. A method for producing a protein fiber according to the present invention includes: a pre-shrinking step of shrinking a protein fibril in a relaxed state after drawing and before being wound; a winding step of winding the protein fibril subjected to the pre-shrinking step to obtain a wound product; and a post-shrinking step of shrinking the protein fibril subjected to the winding step in a relaxed state.

An object of the present invention is to provide a method capable of producing a protein fiber in which shrinkage at the time of first contact with moisture after production is more reliably suppressed and generation of crimp is also suppressed. A method for producing a protein fiber according to the present invention includes: a pre-shrinking step of shrinking a protein fibril in a relaxed state after drawing and before being wound; a winding step of winding the protein fibril subjected to the pre-shrinking step to obtain a wound product; and a post-shrinking step of shrinking the protein fibril subjected to the winding step in a relaxed state.

Devices for radiative cooling and optical waveguiding are provided, wherein the devices comprise a fabric including one or more fibers extending for a length in a longitudinal direction and a plurality of void structures positioned within each of the one or more fibers and extended over the length of each of the one or more fibers. Each of the plurality of void structures is configured to scatter at least a portion of an electromagnetic radiation received thereon to thereby radiatively cool the object.

Devices for radiative cooling and optical waveguiding are provided, wherein the devices comprise a fabric including one or more fibers extending for a length in a longitudinal direction and a plurality of void structures positioned within each of the one or more fibers and extended over the length of each of the one or more fibers. Each of the plurality of void structures is configured to scatter at least a portion of an electromagnetic radiation received thereon to thereby radiatively cool the object.

The present invention relates to a modified fibroin including a domain sequence represented by Formula 1: [(A).sub.nmotif-REP].sub.m or Formula 2: [(A).sub.nmotif-REP].sub.m−(A).sub.n motif, in which the domain sequence has an amino acid sequence with a reduced content of a glutamine residue equivalent to an amino acid in which one or a plurality of glutamine residues in REP are deleted or substituted with other amino acid residues, as compared with a naturally occurring fibroin.

The present invention relates to a modified fibroin including a domain sequence represented by Formula 1: [(A).sub.nmotif-REP].sub.m or Formula 2: [(A).sub.nmotif-REP].sub.m−(A).sub.n motif, in which the domain sequence has an amino acid sequence with a reduced content of a glutamine residue equivalent to an amino acid in which one or a plurality of glutamine residues in REP are deleted or substituted with other amino acid residues, as compared with a naturally occurring fibroin.

An object of the present invention is to provide an agent for imparting a cool touch feeling property and a water-absorbing and quick-drying property. The agent for imparting a cool touch feeling property and a water-absorbing and quick-drying property contains a modified fibroin as an active ingredient.

An object of the present invention is to provide an agent for imparting a cool touch feeling property and a water-absorbing and quick-drying property. The agent for imparting a cool touch feeling property and a water-absorbing and quick-drying property contains a modified fibroin as an active ingredient.

One embodiment of the present invention provides a nonwoven fabric containing silk fibers in which an abs intensity ratio [abs (1650)/abs (1620)], which is a ratio of an intensity of a peak positioned in a vicinity of 1650 cm.sup.−1 [abs (1650)] in an infrared absorption spectrum to an intensity of a peak positioned in a vicinity of 1620 cm.sup.−1 [abs (1620)] in an infrared absorption spectrum, is larger than 0.65 and 1.90 or less, and a method for producing the nonwoven fabric containing silk fibers.