News tagged with selenium

Diet may reduce risk of prostate cancer

A new review published in the Journal of Human Nutrition and Dietetics assessed whether certain modifications in diet have a beneficial effect on the prevention of prostate cancer. Results suggest that a diet low in fat and ...

Jun 03, 2009
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Antioxidants do help arteries stay healthy: study

Long-term supplementation with dietary antioxidants has beneficial effects on sugar and fat metabolism, blood pressure and arterial flexibility in patients with multiple cardiovascular risk factors. Researchers writing in ...

Jul 05, 2010
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Selenium protects men against diabetes

The role of selenium in diabetes has been controversial, with some studies suggesting that it raises diabetes risk and others finding that it is protective. Now, research published in BioMed Central's open access journal ...

Mar 17, 2010
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Selenium shows no benefit in prevention of lung cancer

Selenium, a supplement taken daily by millions in hopes of protection against cancer and a host of other diseases, has proven to be of no benefit in reducing a patient's risk of developing lung cancer - either a recurrence ...

Jun 05, 2010
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Sugar is good for a sweet heart: new study

(Medical Xpress) -- A new type of sugar could help prevent heart disease, according to latest research by Dr Corin Storkey and Professor Carl Schiesser from the ARC Centre of Excellence for Free Radical Chemistry and Biotechnology ...

Dec 05, 2011
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Selenium

Selenium (pronounced /səˈliːniəm/) is a chemical element with the atomic number 34, represented by the chemical symbol Se, an atomic mass of 78.96. It is a nonmetal, chemically related to sulfur and tellurium, and rarely occurs in its elemental state in nature.

Isolated selenium occurs in several different forms, the most stable of which is a dense purplish-gray semi-metal (semiconductor) form that is structurally a trigonal polymer chain. It conducts electricity better in the light than in the dark, and is used in photocells (see allotropes section below). Selenium also exists in many non-conductive forms: a black glass-like allotrope, as well as several red crystalline forms built of eight-membered ring molecules, like its lighter chemical cousin sulfur.

Selenium is found in economic quantities in sulfide ores such as pyrite, partially replacing the sulfur in the ore matrix. Minerals that are selenide or selenate compounds are also known, but all are rare. The chief commercial present uses for selenium are in glassmaking and in chemicals and pigments. Electronic uses for selenium, once important, have been supplanted by silicon semiconductor devices.

Selenium salts are toxic in large amounts, but trace amounts of the element are necessary for cellular function in most, if not all, animals, forming the active center of the enzymes glutathione peroxidase and thioredoxin reductase (which indirectly reduce certain oxidized molecules in animals and some plants) and three known deiodinase enzymes (which convert one thyroid hormone to another). Selenium requirements in plants differ by species, with some plants apparently requiring none.

This text uses material from Wikipedia, licensed under CC BY-SA

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