Which preposition to use with upturn

in Occurrences 2%

Well, you can't wait for the upturn in here.

of Occurrences 1%

" When they entered the edge of the Miette clearing and saw the glow of lights ahead of them, Aldous caught the sudden upturn of his companion's face, laughing at him in the starlight.

to Occurrences 1%

He caught her eyes, turned swiftly to him, and they were laughing at him, and there came a sudden pretty upturn to her chin as he continued to stare, and he saw again the colour deepening in her face.

Which preposition to use with  upturn