Multiple sclerosisMultiple sclerosis (MS) is the most common demyelinating disease, in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This damage disrupts the ability of parts of the nervous system to transmit signals, resulting in a range of signs and symptoms, including physical, mental, and sometimes psychiatric problems. Specific symptoms can include double vision, visual loss, muscle weakness, and trouble with sensation or coordination.
Acetyl groupIn organic chemistry, acetyl is a functional group with the chemical formula and the structure . It is sometimes represented by the symbol Ac (not to be confused with the element actinium). In IUPAC nomenclature, acetyl is called ethanoyl, although this term is rarely heard. The acetyl group contains a methyl group () single-bonded to a carbonyl (), making it an acyl group. The carbonyl center of an acyl radical has one nonbonded electron with which it forms a chemical bond to the remainder R of the molecule.
Solar spiculeIn solar physics, a spicule, also known as a fibril or mottle, is a dynamic jet of plasma in the Sun's chromosphere about 300 km in diameter. They move upwards with speeds between 15 and 110 km/s from the photosphere and last a few minutes each before falling back to the solar atmosphere. They were discovered in 1877 by Angelo Secchi, but the physical mechanism that generates them is still hotly debated. Spicules last for about 15 minutes; at the solar limb they appear elongated (if seen on the disk, they are known as "mottles" or "fibrils").
Erythrocyte sedimentation rateThe erythrocyte sedimentation rate (ESR or sed rate) is the rate at which red blood cells in anticoagulated whole blood descend in a standardized tube over a period of one hour. It is a common hematology test, and is a non-specific measure of inflammation. To perform the test, anticoagulated blood is traditionally placed in an upright tube, known as a Westergren tube, and the distance which the red blood cells fall is measured and reported in millimetres at the end of one hour.
Solar prominenceA prominence, sometimes referred to as a filament, is a large plasma and magnetic field structure extending outward from the Sun's surface, often in a loop shape. Prominences are anchored to the Sun's surface in the photosphere, and extend outwards into the solar corona. While the corona consists of extremely hot plasma, prominences contain much cooler plasma, similar in composition to that of the chromosphere. Prominences form over timescales of about a day and may persist in the corona for several weeks or months, looping hundreds of thousands of kilometers into space.
