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Study design. The evening shift (E) was from 15:45 to 0:30; the night shift (N) was from 0:00 to 8:45; and the off duty (O) was the first half period during intervention or control (T1) and the second half period during intervention or control (T2). Black circles represent the timing of measurement; gray arrows represent repeated measurement; and black dash arrows represent measurement after each shift.
