The mole is the basic unit of substance.
Definition: The amount of substance that contains as many elementary units as there are atoms in 0.012 kg of carbon-12.

(Osm) A unit of osmotic pressure used in physical chemistry, cell biology, and medicine.
Definition: 1 osmole is the osmotic pressure of a one molar solution (that is, a solution with a concentration of one mole per liter of solvent) of a substance that does not dissociate.
If chemical solutions are separated by a semipermeable membrane (a membrane that resists the passage of dissolved substances but permits the passage of the solvent, usually water), then the solvent will diffuse across the membrane to equalize the concentrations. This process is called osmosis.
Solutions with higher concentrations of dissolved substances are said to have higher osmotic pressure than solutions having lower concentrations; thus the solvent moves from an area of low osmotic pressure to an area of higher osmotic pressure.
Osmotic pressure depends on the total number of dissolved particles, so for a substance that dissociates into two ions, such as ordinary salt (sodium chloride), a one molar solution has an osmotic pressure of 2 osmoles. In practice, most measurements are in milliosmoles (mOsm). Typical values range from 20 mOsm for fresh water through 290 mOsm for typical human blood plasma to 1010 mOsm for salt water from the open ocean.

Structure formed of atoms of various elements.

Molecular Imaging is a new diagnostic discipline to visualize biological processes.
Molecular magnetic resonance imaging (mMRI) offers the potential to image tissues at the cellular and subcellular level. Targeted MR contrast agents enhance the diagnostic specificity and range of molecular magnetic resonance imaging.
Other modalities that can be used for noninvasive molecular imaging:

See also Nanoparticle, Monocrystalline Iron Oxide Nanoparticle, Polycrystalline Iron Oxide Nanoparticles, Liposomes, Monoclonal Antibodies, Bimodal Imaging, Tumor Specific Agents, and Intracellular Contrast Agents.

(MT) Magnetization Transfer was accidentally discovered by Wolff and Balaban in 1989. Conventional MRI is based on the differences in T1, T2 and the proton density (water content and the mobility of water molecules) in tissue; it relies primarily on free (bulk) water protons. The T2 relaxation times are greater than 10 ms and detectable. The T2 relaxation times of protons associated with macromolecules are less then 1 ms and not detectable in MRI.
Magnetization Transfer Imaging (MTI) is based on the magnetization interaction (through dipolar and/or chemical exchange) between bulk water protons and macromolecular protons. By applying an off resonance radio frequency pulse to the macromolecular protons, the saturation of these protons is then transferred to the bulk water protons. The result is a decrease in signal (the net magnetization of visible protons is reduced), depending on the magnitude of MT between tissue macromolecules and bulk water. With MTI, the presence or absence of macromolecules (e.g. in membranes, brain tissue) can be seen.
The magnetization transfer ratio (MTR) is the difference in signal intensity with or without MT.

See also Magnetization Transfer Contrast.