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)
Pleurisy, also known as pleuritis, is swelling of the thin lining around the chest cavity and lungs, also known as the pleura. This lining creates a smooth surface so the lungs glide easily in the chest while breathing. When the lining swells, the lungs rub painfully against the chest, causing swelling and chest pain. In some cases, fluid can collect between the pleura. This is called pleural effusion. When there is no fluid, the condition is called dry pleurisy.