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Selenium
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Selenium is also able to convert ac electricity to dc and is extensively, used in rectifiers. Below its melting point, selenium is a p-type semiconductor, and is finding many uses in electronic and solid state applications.[4] Selenium is available in soluble forms including chlorides, nitrates and acetates . These compounds are also manufactured as solutions at specified stoichiometries.[5] Selenium is often associated with marine shales and therefore South Dakota has areas of high selenium concentration in soil and water. Soils that are high in concentration of selenium are referred to as "seleniferous" soils.[6]
Selenium is used by the body to aid in metabolism. Selenium supplements have been widely promoted for conditions such as cold sores, shingles, arthritis and multiple sclerosis.[7] Selenium is an essential trace element in the human diet, and exposures may occur through the use of dietary supplements as well as via exposure to industrial compounds. Serious acute poisoning is reported most commonly from ingestion of selenious acid in gun bluing (coating) solutions.[8] Selenium is found in Brazil nuts and whole grain cereals, as well as in some meats and seafood. The selenium content of foods is related to the selenium content in the soil in which the foods are grown or the animals graze.[9] Selenium is an antioxidant and appears to regenerate vitamins E and C so that they can continue to fight free radicals. Selenomethionine is its best form.[10] Selenium is a mineral found in vegetables and grains grown in selenium rich soil, such as that found in northern Nebraska and the Dakotas. Mushrooms, snapper, halibut, cod, tuna and salmon have high selenium levels, a serving providing 50-90 percent of the recommended daily intake.[11] Selenium is essential for the conversion of Synthroid (T4) into triiodothyronine (T3) which is the hormone that affects metabolism. I would think that if your selenium were adequate you?d feel the Synthroid right away.[12]
Selenium is one such nutrient element. Toxicology is the branch of pharmacology that deals with the nature, effects, detection and treatment of poisons.[13] Selenium is a bioaccumulative pollutant, meaning that it accumulates in the food chain through uptake and consumption by plants and wildlife, and can cause adverse effects on fish and birds. There are different forms of selenium, some more harmful than others.[14] Selenium is an interesting compound as it is classified as an essential nutrient so it appears in all kinds of health food supplements and yet there are severe limitations on the discharge of this compound. Selenium forms as many as five different oxidation states.[15] Selenium is not meant for unit testing. [16] Selenium is another nutrient often linked to the immune system. Selenium deficiency is associated with impaired immune response, and supplementation to replete the deficiency stimulates the immune system.[17] Selenium is a trace element essential for life, but is also toxic at relatively low concentrations. If present in water, selenium is known to bioaccumulate in aquatic flora and fauna resulting in the decimation of fish and bird populations. Selenium is required for incorporation into selenocysteine, which is the 21st amino acid identified in ribosomal-mediated peptide synthesis (reviewed by Allmang and Krol, 2006 ). Selenoproteins have been described in animals (including humans), bacteria and archaea, and the green alga Chlamydomonas reinhardtii (Novoselov et al., 2002 ), but not in higher plants or fungi (Allmang and Krol, 2006 ).[19] Selenium is very important because it forms part of the structure of the important antioxidant enzyme glutathione peroxidase, which in turn recycles glutathione. Selenium may also protect against cancers and cardiovascular disease.[20] Selenium is necessary for growth and fertility in animals and for the prevention of a variety of diseases. The minimum intake requirement of Se for a given species varies with the form of Se ingested and dietary composition.[21] Selenium is an essential nutrient , which we require in tiny quantities - 70 micrograms for an adult male, 55 for an adult female, less for children. It was discovered to be a toxin causing dermatologic lesion s, diarrhoea and death almost twenty-five years before people realised that it is a nutrient; doses only ten times the RDA can have toxic effects, while selenium deficiency is relatively uncommon.[22] Selenium is an essential micronutrient for several species, including humans, and is part of several enzymes such as glutathione peroxidase, an enzyme involved in cellular defense against oxidative damage, and heme oxidase. While low doses of selenium are essential, high doses of selenium or a deficiency of dietary selenium may cause a toxic response.[23] Selenium is also essential for normal functioning of the immune system and thyroid gland. Selenium is found in many foods such as seafood, lean meats, grains, eggs and garlic. It is unknown that how much selenium is enough for men.[25] Selenium is a trace element supplied by certain foods and dietary supplements. The study showed that men with low blood levels of selenium are four to five times more likely to develop prostate cancer. Selenium is an web app functional testing tool written by ThoughtWorks. Selenium uses JavaScript and Iframes to embed a test automation engine in your browser, allowing Selenium to execute in any JavaScript-enabled browser.[27] Selenium is found in the earth?s crust, but its concentration is lower than gold?s. Selenium finds its way into plants, then works its way up the food chain.[28] Selenium is now just coming into its own, . The book, published in 1924, referred, of course, to its value as a conductor of electricity when illuminated.[29] Selenium is an essential trace mineral and is necessary for normal health and productivity in animals. When fed in excess, selenium is toxic to tissue cells and becomes an environmental contaminant through fecal excretion.[30] Selenium is found in many foods, but it can be hard to know if you're getting the recommended 55 mcg a day because amounts vary based on the soil in which food is grown and the feed livestock consume. To meet your requirement, try a supplement or eat a varied diet and opt for foods grown in different areas such as nuts from California.[31] Selenium is truly a critical thing to keep an eye on. Levels can be determined by blood test. Selenium is part of an enzyme called glutathione peroxidase that has been shown to reduce the rates of cancer in humans (Clark et al.) [33] Selenium is thought to prompt possibly prompt cancer cells to self-destruct, promoting DNA repair and boost immunity. And a little goes a long way.[34] Selenium is necessary for the production of the seleno enzyme needed to convert T4 into T3. Selenium and zinc are also used in the production of thyroid hormone.[35] Selenium is extensively used in the vulcanization of rubber, in the manufacture of red glass and some enamels, as a decolorizer of glass to counteract the green of iron compounds, in electronics, and in xerography. [36] Selenium is an essential trace element and is involved in antioxidant protection and redox-regulation in humans. Several adverse effects of radiotherapy and chemotherapy in cancer patients as well as cellular processes that maintain chronic lymphoedema have been linked to oxidative cell damage in the human body.[37] Selenium is toxic in large amounts. Selenosis (chronic selenium toxicity) results in symptoms such as gastrointestinal and nervous system disturbances, brittleness and loss of hair and nails, a garliclike odour to the breath, and skin rash.[38] Selenium is now known to be part of several enzymes and also plays a role in thyroid hormone metabolism. [39] Selenium is used in free radical elimination and other antioxidant enzymes, and also plays a role in the functioning of the thyroid gland. Selenium is the central element in glutathione peroxidase (GPx), an antioxidant enzyme that protects cells against the oxidative damage caused by peroxides and free radicals.[40] Selenium is an essential trace element that occurs naturally in the environment. Selenium is widely distributed in rocks, soils, water and living organisms. Selenium is one such element. In large quantities, selenium is toxic, but, in trace amounts, it is absolutely essential for life in many organisms, including humans.[42] Selenium is enjoying growing prominence as a cancer chemopreventive agent and is also of great interest in the AIDS arena. Unfortunately, it gets toxic at levels not terribly far above those required for nutritional uses, and rather high amounts appear to be required, at least for cancer prevention.[43] Selenium is passed from the placenta to the fetus during late gestation, and proper selenium supplementation to ewes will assist in preventing white muscle disease in lambs. Selenium is often provided in complete mineral mixes offered free-choice (provide mineral specifically formulated for sheep).[44]
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