Category: X
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Xerophyte
A plant that grows well in dry conditions. A plant that is adapted to, and needs, dry desert climate or is particularly hardy in periodic droughts.
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Xerophthalmia
A medical condition in which the eye fails to produce tears. Advanced vitamin A deficiency in which the epithelium of the cornea and conjunctiva of the eye deteriorate because of impairment of the tear glands, resulting in dryness then ulceration, leading to blindness. Excessive dryness of the conjunctiva. A condition of the eye, in which…
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Xenobiotics
A chemical (as a drug, pesticide, or carcinogen) that is foreign to a living organism. Substances foreign to the body, including drugs and some food additives. An antibiotic not produced by the body, and thus foreign to it.
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Xanthones
Unique class of biologically active phenol compounds with the molecular formula C13H8O2 possessing antioxidant properties, discovered in the mangosteen fruit.
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Xanthine oxidase
A flavoprotein enzyme containing a molybdenum cofactor (Moco) and (Fe2S2) clusters, involved in purine metabolism. In humans, inhibition of xanthine oxidase reduces the production of uric acid, and prevent hyperuricemia and gout. An enzyme responsible for production of free radicals in the body.
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X-linked agammaglobulinemia
Also known as X-linked hypogammaglobulinemia, XLA, Bruton type agammaglobulinemia, Bruton syndrome, or sex-linked agammaglobulinemia; a rare x-linked genetic disorder that affects the body’s ability to fight infection.
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X‐ray tube
Vacuum tube designed to produce X‐ray photons. In the tube, there is a cathode to emit electrons into the vacuum and an anode to collect the electrons, where the X‐rays are produced by bremsstrahlung.
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X‐ray
Limited part of the spectrum of electromagnetic radiation; a self‐propagating transverse oscillating wave of electric and magnetic fields.
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Xerostomia
Dryness of the mouth due to lack of or inadequate secretions (e.g., inadequate salivary secretions). Dry mouth; reduced amount of saliva. Dry mouth may be caused by disease, some medications, radiation therapy, or aging. The condition may be treated by the administration of a saline substitute. Dryness of the mouth, caused by lack of a…
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Xeroradiography
The dry photoelectric process by which an X‐ray image is captured using metal plates coated with a semiconductor, such as selenium. A diagnostic technique to detect breast cancer in its early developmental stages. photoelectric process for producing an X-ray image that uses lower radiation and shorter exposure time than conventional X-ray techniques; it is used…