You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Thermal and electrical conduction in 6.4 nm thin gold films. For sub-10 nm thin metallic films, very little knowledge is available so far on how electron scattering at surface and grain boundaries reduces the thermal transport. This work reports on the first time characterization of the thermal and electrical conductivities of gold films of 6.4 nm average thickness. The electrical (σ) and thermal (k) conductivities of the Au film are found to be reduced dramatically from their bulk counterparts by 93.7% (σ) and 80.5% (k). Its Lorenz number is measured as 7.44 × 10(-8) W Ω K(-2), almost a twofold increase from the bulk value. The Mayadas-Shatzkes model is used to interpret the experimental results and reveals very strong electron reflection (77%) at grain boundaries.
{"Chemical": ["Au"]}