Medical research

Compact electronic nose to identify human lung diseases

Researchers from Russia and Italy have proposed a compact sensor system that can implement the functionality of an electronic nose device and have developed a reproducible technology for its manufacture. The device is a flexible ...

Medical research

Acoustic growth factor patterning

For optimally engineered tissues, it is important that biological cues are delivered with appropriate timing and to specific locations. To aid in this endeavor, researchers have combined acoustic droplet ejection (ADE) technology ...

Cardiology

Too much salt weakens the immune system

A high-salt diet is not only bad for blood pressure, but also for the immune system. This is the conclusion of a current study under the leadership of the University Hospital Bonn. Mice fed a high-salt diet were found to ...

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Sodium

Sodium (pronounced /ˈsoʊdiəm/) is a metallic element with a symbol Na (from Latin natrium or Arabic natrun) and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals within "group 1" (formerly known as ‘group IA’). It has only one stable isotope, 23Na.

Elemental sodium was first isolated by Sir Humphry Davy in 1806 by passing an electric current through molten sodium hydroxide. Elemental sodium does not occur naturally on Earth, but quickly oxidizes in air and is violently reactive with water, so it must be stored in an inert medium, such as a liquid hydrocarbon. The free metal is used for some chemical synthesis and heat transfer applications.

Sodium ion is soluble in water in nearly all of its compounds, and is thus present in great quantities in the Earth's oceans and other stagnant bodies of water. In these bodies it is mostly counterbalanced by the chloride ion, causing evaporated ocean water solids to consist mostly of sodium chloride, or common table salt. Sodium ion is also a component of many minerals.

Sodium is an essential element for all animal life and for some plant species. In animals, sodium ions are used in opposition to potassium ions, to allow the organism to build up an electrostatic charge on cell membranes, and thus allow transmission of nerve impulses when the charge is allowed to dissipate by a moving wave of voltage change. Sodium is thus classified as a “dietary inorganic macro-mineral” for animals. Sodium's relative rarity on land is due to its solubility in water, thus causing it to be leached into bodies of long-standing water by rainfall. Such is its relatively large requirement in animals, in contrast to its relative scarcity in many inland soils, that herbivorous land animals have developed a special taste receptor for sodium ion.

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