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.
There are a variety of uses for Hydrogen. It is the lightest element and can be used as a lifting agent in balloons. Since Hydrogen gas is highly flammable, it can be dangerous to use.But this property and others make Hydrogen suitable for use as a fuel.The most common use of Hydrogen is in chemical processes and reactions.here are a variety of uses for Hydrogen. It is the lightest element and can be used as a lifting agent in balloons. Since Hydrogen gas is highly flammable, it can be dangerous to use.