ASBESTOS |
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Asbestos (a misapplication of Latin: asbestos "quicklime" from Greek ἄσβεστος: a-, "not"; sbestos, "extinguishable") describes any of a group of fibrous metamorphic minerals of the hydrous magnesium silicate variety. The name is derived for its historical use in lamp wicks; the resistance of asbestos to fire has long been exploited for a variety of purposes. It was used in fabrics such as Egyptian burial cloths and Charlemagne's tablecloth, which, according to legend, he threw in a fire to clean. Asbestos occurs naturally in many forms (see below); it is mined from metamorphic deposits.
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CANCER - GENERAL |
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Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these cells to invade other tissues, either by direct growth into adjacent tissue through invasion or by implantation into distant sites by metastasis. This unregulated growth is caused by damage to DNA, resulting in mutations to genes that encode for proteins controlling cell division. Many mutation events may be required to transform a normal cell into a malignant cell. These mutations can be caused by chemicals or physical agents called carcinogens, by close exposure to radioactive materials, or by certain viruses that can insert their DNA into the human genome. Mutations occur spontaneously, or are passed down generations as a result of germ line mutations.
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