Before revision:  The underling structure of this asymmetrical heat flow is the hydrogen bond of normal length (~2.85 {\AA}) , that can act as a thermal diode. Also asymmetrical heat diffusion is due, in } a higher scale, to local URLanization of residues  .
After revision:  The underling structure of this asymmetrical heat flow is the hydrogen bond of normal length (~2.85 {\AA}) , that can act as a thermal rectifier. In contrast, thermal rectification was compromised in short hydrogen bonds (~2.60 } a higher scale, to local URLanization of residues .