UN Thread Types. UN (Unified) is a specification of the shape and dimensions of the thread for a given size (diameter) of fastener and number of threads per inch of fastener length. UN bolts and machine screws are the type of fastener in everyday use in the US, UK, and Canada. UN, UNR, and UNJ thread dimensions are measured in Imperial units.
Causes The airway can become narrowed or blocked due to many causes, including: Allergic reactions in which the trachea or throat swell closed, including allergic reactions to a bee sting, peanuts, antibiotics (such as penicillin), and blood pressure medicines (such as ACE inhibitors) Chemical burns and reactions. Epiglottitis (infection of the structure separating the trachea from the esophagus)
Posted by Dr. Chris. Tweet. Tracheitis is the inflammation of the windpipe (trachea). Most cases of tracheitis are due to a bacterial infection, however, a number of other factors, both infectious and non-infectious, may also cause inflammation of the trachea.ertussis is caused by the bacteria Bordetella pertussis. Viral infections like croup, which is caused by a number of viral species particularly the parainfluenza species, may cause inflammation of the larynx and trachea (laryngotracheitis) or larynx, trachea and bronchi (laryngotracheobronchitis).