8542
Both compressive and tensile mechanical stress were applied continuously and reversibly to the nanowire , resulting in a remarkable decrease of the bandgap of up to 296 meV at 3 . 5 % of strain .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 None