21. The APF for negative pressure half mask respirators are twofold. 22. The UL181 test requires a negative pressure of 200 Pa. 23. These units create no negative pressure in the room. 24. That's a negative pressure _ a horrible pressure ." 25. The child actor may experience unique and negative pressures when working under tight production schedules. 26. When breathing, downward motion of the thoracic diaphragm creates negative pressure in the thoracic cavity. 27. The difference of the APF for air purifying negative pressure full-facepiece masks are not large. 28. No longer is the Clinton administration striking a balance between positive inducements and negative pressures . 29. Hospitals do not have large numbers of negative pressure rooms, designed to contain infected air. 30. Without proof that sizable negative pressures exist in the xylem, the pull theory remains speculative.
