How to use Selenium in a sentence
Owing to the variable illumination of the selenium thus produced, the resistance of the latter, and therefore the intensity of the current sent through the line to the receiving station by the battery, will be altered accordingly.
The mineral nearly always contains a small amount of silver, and sometimes antimony, arsenic, copper, gold, selenium, &c. Argentiferous galena is an important source of silver; this metal is present in amounts rarely exceeding %, and often less than o 03% (equivalent to 104 ounces per ton).
By means of this " light-relay " the intensity of the light acting at any moment upon the sensitized paper is made proportional to the illumination of the selenium in the transmitter.
When there is appreciable absorption as in the case of the vapours of chlorine, bromine, iodine, sulphur, selenium and arsenic, luminosity begins at a red heat.
It combines readily with fluorine, chlorine and bromine, and also with sulphur, selenium, phosphorus, &c.Advertisement
A totally reflecting prism placed inside the glass cylinder projects the light which penetrates the film upon a selenium cell situated at the end of the cylinder.
To eliminate the sluggish action of the selenium transmitter a selenium cell similar to that at the transmitting station is arranged at the receiving apparatus, and exposed to precisely similar variations of light, the arrangement being such that the lag of this cell counteracts the lag of the transmitting cell.
Hittorf, who carefully investigated the effects produced by heat; crystalline selenium possesses a very striking property, viz.
The elements which go to form heterocyclic rings, in addition to carbon, are oxygen, sulphur, selenium and nitrogen.
The three primary members are furfurane, thiophene and pyrrol, each of which contains four methine or CH groups, and an oxygen, sulphur and imido (NH) member respectively; a series of compounds containing selenium is also known.Advertisement
Now consider the effect of replacing sulphur by selenium.
Antimony, bismuth, selenium, tellurium, chromic iron ore, tin, nickel, cobalt, vanadium, titanium, molybdenum, uranium and tantalum are produced in the United States in small amounts, but such production in several cases has amounted to only slight discoveries, and in general they are of little importance in the market.
In the same year Berzelius discovered selenium in a deposit from sulphuric acid chambers, his masterly investigation including a study of the hydride, oxides and other compounds.
If, on the other hand, the sulphur system be replaced by a corresponding selenium system, an element of higher atomic weight, it would be expected that a slight increase would be observed in the vertical parameter, and a greater increase recorded equally in the horizontal parameters.
It may conveniently be extended to similar mixtures of sulphur and selenium or tellurium, of bismuth and sulphur, of copper and cuprous oxide, and of iron and carbon, in fact to all cases in which substances can be made to mix in varying proportions without very marked indication of chemical action.Advertisement
Bismuth forms compounds similar to the trisulphide with the elements selenium and tellurium.
Small quantities are occasionally met with in iron pyrites, and hence tellurium is found with selenium in the flue dust, or chamber deposits of sulphuric acid works.
These substances, and also carbon, sulphur, selenium and tellurium, render the metal very brittle.
Such, for instance, were those of Spindler and Wrangell in the Black Sea by sinking an electric lamp, those of Paul Regnard by measuring the change of electric resistance in a selenium cell or the chemical action of the light on a mixture of chlorine and hydrogen, by which he found a very rapid diminution in the intensity of light even in the surface layers of water.
Crookes presumed that his thallium was something of the order of sulphur, selenium or tellurium; but Lamy, who anticipated him in isolating the new element, found it to be a metal.Advertisement
The best raw materials for the preparation of thallium are the flue-dusts produced industrially in the roasting of thalliferous pyrites and the "chamber muds" accumulating in vitriol-chambers wrought with such pyrites; in both it is frequently associated with selenium.
Traces of gold, silver, selenium or thallium are sometimes present, and the mineral is sometimes worked as an ore of gold or silver.
The impurities contained in coarse-copper are mainly iron, lead, zinc, cobalt, nickel, bismuth, arsenic, antimony, sulphur, selenium and tellurium.
The principles have long been known on which is based the electrolytic separation of copper from the certain elements which generally accompany it, whether these, like silver and gold, are valuable, or, like arsenic, antimony, bismuth, selenium and tellurium, are merely impurities.
In this process, the residues are boiled with a dilute sulphuric acid to which nitric acid and potassium chlorate are added in order to transform the element into selenic acid, H 2 Se0 4, which is then reduced to selenious acid, H 2 Se0 3, by boiling with hydrochloric acid, and finally to selenium by sulphur dioxide.Advertisement
The red crystalline variety is obtained by crystallization of selenium from carbon bisulphide, or by leaving the amorphous form in contact with the same solvent.
A colloidal selenium was obtained by C. Paal and C. Koch (Ber., 1905, 38, p. 526) by reducing selenious acid dissolved in an aqueous solution of sodium protalbate with hydrazine hydrate and hydrochloric acid, the precipitate obtained being then dissolved in sodium carbonate.
The specific gravity of selenium is 4.8; the specific heat varies from 0.0716 to 0.1147, depending upon the particular form.
Selenium combines directly with hydrogen when heated in the gas, and with fluorine in the cold.
Its aqueous solution is unstable, gradually depositing red selenium on standing.Advertisement
It dissolves selenium.
Selenium dioxide, Se02, is prepared by burning selenium in oxygen, or by oxidizing selenium with nitric acid and heating the residue.
It is decomposed by hydriodic acid with liberation of selenium and iodine, and by ammonia with formation of selenium and nitrogen.
Selenious acid, H 2 SeO 3, is obtained in the crystalline form when a solution of selenium dioxide in water is concentrated over sulphuric acid.
Oxidizing agents readily convert it into selenic acid, whilst reducing agents transform it into selenium.Advertisement
Selenium sulphoxide, SeS0 3, is formed as a yellowish crystalline mass when selenium is warmed with sulphur trioxide.
Selenosulphuric acid, H 2 SeS0 3, is only known in the form of its salts, which are usually obtained by the action of selenium on solutions of the metallic sulphites, a selenotrithionate being simultaneously produced.
It is readily decomposed by acids with liberation of sulphur dioxide and selenium.
It crystallizes in needles, possesses an alkaline reaction, and is readily decomposed by acids with liberation of selenium.
Numerous determinations of the atomic weight of selenium have been made.Advertisement
The element combines directly with the halogens, sulphur and selenium, and most of the metals burn in its vapour forming phosphides.
All the thallium and selenium on the market is obtained from this source.
Arsenic compounds containing selenium and sulphur are known, such as arsenic seleno-sulphide, AsSeS2, and arsenic thio-selenide, AsSSe2.
Gross deficiency of dietary selenium may cause many heart problems, including arrhythmia.
Interactions Vitamin E exerts antioxidant effects in combination with other antioxidants including beta carotene, vitamin C and selenium.Advertisement
Vitamin E and selenium supplements may prevent prostate cancer, although the evidence is not yet conclusive.
Lambs seriously deficient in copper, selenium or cobalt will fail to thrive.
I had the vet and it was mineral deficiency of cobalt, selenium and zinc, together with parasitic gastroenteritis caused by worms.
Selenium, itself an antioxidant, is required to activate one of the most important antioxidants found in the body, called glutathione.
Selenium Selenium is also important in the process of destroying hydrogen peroxide.Advertisement
When eaten by the animal, these PUFAs are converted into the toxic peroxides, the antagonists of vitamin E and selenium.
Its selenium product will contain sodium selenate rather than the banned selenium yeast.
Manufacturers are expected to replace organic selenium with sodium selenite.
However UK wheat still contains more selenium than European grown wheat.
Minerals important to the look and to the health of the skin include selenium, copper and zinc.
In other words, most UK citizens aren't getting nearly enough selenium in their diets.
In addition, subjects who took selenium cleared the virus from their bodies faster than the placebo subjects.
For the time being, you have the option to supplement with as much selenium as you please.
Less than optimal intake of selenium may have adverse effects on psychological function, even in the absence of signs of frank selenium deficiency.
Mushrooms, one of my favorite foods, are a good source of the antioxidant selenium as well as potassium and B vitamins.
Foster argues that the fall of selenium levels trigger the reduction in CD4 cells, which in turn cause further decline in serum selenium.
Brazil nuts These are rich in the mineral selenium, which has antioxidant effects that may help protect against cancer.
Diets based mainly on silage could be deficient in vitamin E and the trace element selenium.
You'll also be introduced to suitable developers, as well as basic sepia, selenium and blue toning of fibre-based prints.
If these are not adequate, I dispense selenium sulfide or benzyl peroxide shampoos.
The most common additives are sulfur and lead, other elements used include tellurium, selenium and bismuth.
The Korn telephotographic apparatus is based on the principle of an apparatus devised by Shelford Bidwell in 1881 for the electrical transmission of pictures to a distance, in which use was made of the change in electrical resistance which selenium undergoes when acted upon by light.
An illumination of variable intensity (according to the deeper or lighter shades of the portion of the picture on which the light falls) thus takes place on the selenium cell.
As the glass cylinder, driven by a motor, revolves upon its axis while also advancing (by means of a screw thread on the axis), all portions of the picture are successively brought under the beam or pencil of light and cause a beam of varying intensity to fall on the selenium cell.
Metallic selenium is a conductor of electricity, and its conductivity is increased by light; this property has been utilized in apparatus for transmitting photographs by telegraphy (see Telegraph).
Selenium fluoride, SeF4, is obtained as a colourless liquid by the direct action of fluorine or selenium (P. Lebeau, Comptes rendus, 1907, 144, p. 1042).
In other words, most UK citizens are n't getting nearly enough selenium in their diets.
Providing there is selenium in the soil there will also be some in your asparagus.
Although topical agents are ineffective on their own, it has been found beneficial to use a selenium sulfide shampoo together with oral griseofulvin.
Not a single case of selenium toxicity was reported in any of the patients studied.
Concerns have been raised that selenium intakes in the UK are falling.
To determine heavy atoms such as Selenium atoms in a protein the atomic resolution data is not needed.
After his discovery, physicists soon discovered the photovoltaic effects of selenium, and in 1904 Einstein published a paper describing the photoelectric effect that later won him the Nobel prize in 1923.
Burdock root contains both vitamin A and the chemical selenium which has been shown to help reduce toxins in the body.
Sunflower seeds are good sources of Vitamin B as well as the mineral selenium which acts as an anti-oxidant.
Adequate levels of selenium can prevent a host of health conditions over time.
Certain studies suggest that cancer incidence is lower in areas where soil and foods are rich in the mineral selenium.
As far as human nutrition is concerned, the inorganic nutrients include water, sodium, potassium, chloride, calcium, phosphate, sulfate, magnesium, iron, fluorine, copper, zinc, chromium, manganese, iodine, selenium, and molybdenum.
A daily intake of 0.75 to 5.0 mg selenium may occur in these regions due to the presence of selenium in foods and water.
Early signs of selenium toxicity include nausea, weakness, and diarrhea.
In the case of selenium toxicity resulting from high-selenium soils, toxicity can be prevented by relying on food and water acquired from a low-selenium region.
The minerals that are relevant to human nutrition are water, sodium, potassium, chloride, calcium, phosphate, sulfate, magnesium, iron, copper, zinc, manganese, iodine, selenium, and molybdenum.
Selenium is needed for proper thyroid function.
Selenium supplements are not normally required except in children with phenylketonuria receiving a low-protein diet, although it may sometimes be associated with thyroid problems.
Shampoo containing selenium sulfide can help prevent spread of scalp ringworm, but prescription shampoo or oral medication is usually needed to cure the infection.
Selenium deficiency occurs in regions of the world where soils are selenium-poor and low-selenium foods are produced.
Premature infants are naturally low in selenium with no known serious effects.
Selenium deficiency may occur in premature infants who naturally tend to have about one-third the selenium levels of full-term infants.
Selenium deficiency occurs in regions of the world containing low-selenium soils, including parts of China, New Zealand, and Finland.
Keshan disease, which may be fatal, is thought to result from a combination of selenium deficiency and a virus.
Selenium can be measured in plasma or red blood cells and compared to normal values.
The activity of an enzyme (glutathione peroxidase) in platelets (small blood cells essential in blood clotting) may be evaluated to assess selenium status.
Selenium deficiency can be treated by supplementation.
Nutritional supplements that may be beneficial include large amounts of antioxidants (vitamins C, A, E, zinc, selenium, and flavenoids), as well as B vitamins and a full complement of minerals (including boron, copper, and manganese).
Selenium is found in tuna, whole grains, and other foods.
The same goes for minerals like selenium, zinc and other common antioxidants.
Strengthens immune system - Bee pollen has both mono and polyunsaturated fats, proteins, vitamins B, C, D, E, and beta-carotene, calcium, magnesium, selenium, nucleic acids, lecithin, and cysteine.
With no artificial colors or artificial flavors, Super C is also full of minerals such as selenium and zinc.
Take time to check the facts about selenium and you'll see this trace mineral offers a number of health benefits.
Selenium is available in fruits, vegetables and whole grains because it is present in the soil in which they grow.
Along with these plant-based sources, selenium is also found in a variety of meats, seafood, wheat germ and yeast.
Another thing to factor in the equation is that when foods are processed much of the selenium is lost.
These two factors make selenium deficiency more possible than first imagined, but for those who don't get enough selenium through diet, it is also found in supplements.
However some experts believe that organic selenium consumed through a healthy diet is better absorbed by the body.
When looking over facts about selenium you'll note deficiencies are relatively uncommon in the US.
Researchers suggest that because selenium fights free radicals, that it may help lower the risk of clogged arteries and decrease heart inflammation.
In addition to helping prevent cancer, some studies show that selenium may also help decrease mortality rates for those who do have cancer.
Our bodies need selenium to create glutathione peroxidase which is used as an antioxidant and promotes a healthy immune system.
With all these benefits there's no real reason to suffer from a selenium deficiency.
In some cases you may think you're getting the selenium you need through the foods you eat, but if they have been grown in selenium deficient soil there's a good chance you may also be lacking in this essential trace mineral.
Selenium is a mineral, and it is an antioxidant nutrient that plays an important role in good vision.
Selenium helps protect against the development of macular degeneration of the eye.
Like the other antioxidant nutrients, it helps prevent oxidative damage to the eye.Food sources of selenium include Brazil nuts, whole wheat, wheat germ, tuna, Swiss chard, and oats.
You can meet your daily recommended intake of selenium by eating just one Brazil nut.
Selenium is required only in trace amounts and can be toxic, so care in supplementation is suggested.
If you're tired of being a slave to extensions and are looking to take your short locks long, popping a selenium supplement can dramatically increase hair growth in black hair.
Selenium works by helping the body utilize protein and since hair is primarily made of protein, a selenium supplement can encourage hair growth and improve hair's strength over time.
Nature Made Selenium Supplement tablets contain 200 micrograms of selenium per capsule, which will promote healthy hair and result in noticeable hair growth.
It's important to remember that taking large amounts of selenium will not contribute to more hair growth and excess amounts can be toxic.
A trial sponsored by the National Cancer Institute is studying the effect of selenium and vitamin E as a means of protecting against prostate cancer is ongoing and is scheduled to conclude in 2013.
Selenium is another supplement said to help fight prostate cancer, but a recent study published in the Journal of Clinical Oncology suggested it is not the right supplement for everyone.
Findings indicate that taking selenium put some at a higher risk for a more aggressive cancer.
Another group studying results of various trials found no evidence that selenium supplements prevent cancer, but suggest further study is necessary.
Vitamin A, C, E and the mineral, selenium, known as the ACES, have been found to be the answer to destroying free radical activity.
Many minerals are thought to play a role in depression, such as calcium, magnesium, iron, zinc and selenium.
Additional nutrients necessary for optimum nutrition include chloride, potassium, sodium, chromium, copper, iodine, fluoride, manganese, molybdenum, selenium, and zinc.
Finally, selenium is found in seafood, grain products and seeds.
Antioxidant functions are derived from vitamins A, C and E, beta carotene, selenium, zinc and a host of other ingredients commonly found in skincare products.
These rocks store a natural reserve of selenium, which is a powerful antioxidant known for its ability to protect the skin from early aging.
Sulphur containing selenium, such as occurs in the isle of Vulcano in the Lipari Isles, may be orange-red; and a similar colour is seen in sulphur which contains arsenic sulphide, such as that from La Solfatara near Naples.