A pulmonary nodule is a discrete opacity in the lung which may be caused by: 1  Neoplasm: benign or malignant. 2  Granuloma: tuberculosis. 3  Infection: roundish pneumonia. 4  Vascular: infarct, varix, granulomatosis with polyangiitis, rheumatoid arthritis.
1 Helium is also commonly used to pressurize and purge systems of unwanted gases. 2  It is also used in controlled atmospheres when the levels of different gases have to be kept constant. 3  It is used as a protective gas when growing silicon and germanium crystals and when producing titanium and zirconium.
helium can be used for many different things. It can be used for advertising purposes, recreation, purge systems, and low-temperature cooling systems. Objects that float in â¦ the air, such as balloons, blimps, Other uses of helium include: - being a protective shield while growing silicon and germanium crystals.