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 is the second-most abundant element in the universe, after hydrogen. Most helium. is recovered from natural gas, so it is not a renewable resource. The demand for helium is. increasing. Many industries use it, including science and healthcare, metal fabrication, electronics and aviation. Uses and Benefits. Helium is a multipurpose molecule with many.