Crossword clues for selenium
selenium
Longman Dictionary of Contemporary English
The Collaborative International Dictionary
Selenium \Se*le"ni*um\, n. [NL., from Gr. selh`nh the moon. So called because of its chemical analogy to tellurium (from L. tellus the earth), being, as it were, a companion to it.] (Chem.) A nonmetallic element of the sulphur group of atomic number 34, analogous to sulphur in its compounds. It is found in small quantities with sulphur and some sulphur ores, and obtained in the free state as a dark reddish powder or crystalline mass, or as a dark metallic-looking substance. It exhibits under the action of light a remarkable variation in electric conductivity, and is used in certain electric apparatus. Symbol Se. Atomic weight 78.96.
Douglas Harper's Etymology Dictionary
element name, Modern Latin, from Greek selene "moon" (see Selene). Named by Berzelius (1818), on analogy of tellurium, with which it had been at first confused, and which was named for the earth. Despite the -ium ending it is not a metal and a more appropriate name selenion has been proposed.
Wiktionary
n. A nonmetallic chemical element (''symbol'' Se) with an atomic number of 34.
WordNet
n. a toxic nonmetallic element related to sulfur and tellurium; occurs in several allotropic forms; a stable gray metallike allotrope conducts electricity better in the light than in the dark and is used in photocells; occurs in sulfide ores (as pyrite) [syn: Se, atomic number 34]
Wikipedia
Selenium is a chemical element with symbol Se and atomic number 34. It is a nonmetal with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium. It rarely occurs in its elemental state or as pure ore compounds in the Earth's crust. Selenium ( Greek σελήνη selene meaning "Moon") was discovered in 1817 by Jöns Jacob Berzelius, who noted the similarity of the new element to the previously discovered tellurium (named for the Earth).
Selenium is found in metal sulfide ores, where it partially replaces the sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores, most often during production. Minerals that are pure selenide or selenate compounds are known but rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells. Applications in electronics, once important, have been mostly supplanted by silicon semiconductor devices. Selenium is still used in a few types of DC power surge protectors and one type of fluorescent quantum dot.
Selenium salts are toxic in large amounts, but trace amounts are necessary for cellular function in many organisms, including all animals. Selenium is an ingredient in many multivitamins and other dietary supplements, including infant formula. It is a component of the antioxidant enzymes glutathione peroxidase and thioredoxin reductase (which indirectly reduce certain oxidized molecules in animals and some plants). It is also found in three deiodinase enzymes, which convert one thyroid hormone to another. Selenium requirements in plants differ by species, with some plants requiring relatively large amounts and others apparently requiring none.
Selenium is a portable software testing framework for web applications. Selenium provides a record/playback tool for authoring tests without learning a test scripting language (Selenium IDE). It also provides a test domain-specific language (Selenese) to write tests in a number of popular programming languages, including Java, C#, Groovy, Perl, PHP, Python and Ruby. The tests can then be run against most modern web browsers. Selenium deploys on Windows, Linux, and Macintosh platforms. It is open-source software, released under the Apache 2.0 license, and can be downloaded and used without charge.
Usage examples of "selenium".
Oxygen, sulfur, selenium, and tellurium made up another, while lithium, sodium, and potassium were placed in a third.
Lycopene, folate, and perhaps selenium, found in tomato products and garlic have anticancer properties.
Besides that, the ore also contained other valuable metals like cobalt and the platinum-group metals, as well as nonmetals like sulfur, arsenic, selenium, germanium, phosphorus, carbon.
Perhaps it picked up iron from the soil, as horsetails pick up calcium oxalate, or some prairie grasses pick up selenium.
It also serves to prevent cancer and heart disease, and low selenium has also been found to be a factor in cot deaths.
That parabolic mirror gathers in the scattered rays, focusses them on the selenium cell which you saw in the middle of the reflector, and that causes the cell to vary the amount of electric current passing through it from a battery of storage cells.
Analysis of the dirt once again showed the lack of certain rare earths, minerals: chitin, Vitamin A and E, most of the rare earths and selenium, although sulphur was present in quantity.
Whatever creatures had lived here before had had different requirements for there were significant basic elements lacking in the soil: chitin, selenium, most of the rare earths, and a paucity of calcium, though quantities of that would have been available from sea creatures.
There was not a soul in the room, nothing but the selenium cell, the chairs, the desk.
The faithful little selenium cell burglar alarm had done the trick.
Upon this dry call of selenium cell (that horn of lunghalloon, Riland's in peril!
In addition to mystical and spiritual matters, the subjects that she chose to discuss with this plump deity included her opinions of the newest boy bands, whether her daily intake of selenium was sufficient, recipes for tofu, what hair styles were likely to be the most flattering to the shape of her face, and whether Pooh of Pooh Corners was a secret opium smoker with a secondary Prozac habit.