Ankylosing spondylitis. Ankylosing spondylitis (AS) is a type of arthritis in which there is long term inflammation of the joints of the spine. Typically the joints where the spine joins the pelvis are also affected. Occasionally other joints such as the shoulders or hips are involved. Eye and bowel problems may also occur.
The allotropes of carbon. Three forms (or 'allotropes') of pure carbon are diamond, graphite and buckminster fullerene (or 'buckyballs'). In all three allotropes the carbon atoms are joined by strong covalent bonds but in such different arrangements that the properties of the allotropes are very different.he allotropes of carbon. Three forms (or 'allotropes') of pure carbon are diamond, graphite and buckminster fullerene (or 'buckyballs'). In all three allotropes the carbon atoms are joined by strong covalent bonds but in such different arrangements that the properties of the allotropes are very different.
The four common allotropes of phosphorus. Elemental phosphorus can exist in several allotropes, the most common of which are white and red solids. Solid violet and black allotropes are also known. Gaseous phosphorus exists as diphosphorus and atomic phosphorus.