1985
Eight severely obese patients ( 4 M / 4 F , mean age +/- SEM : 22 . 8 +/- 1 . 6 years , body mass index , BMI : 39 . 9 +/- 1 . 1 kg / m2 ) underwent an incremental progressive RMET protocol of 11 daily sessions , obtained through the use of a specifically designed respiratory device ( Spiro Tiger (R) ) .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 None