| photonosus | Any disease caused by excessive exposure to or unusual intensity of light, or resulting from phototoxicity or photoallergy. Synonym: photopathy. Origin: photo-+ G. Nosos, disease (05 Mar 2000) |
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| photons | Discrete concentrations of energy, apparently massless elementary particles, that move at the speed of light. They are the unit or quantum of electromagnetic radiation. Photons are emitted when electrons move from one energy state to another. (12 Dec 1998) |
| photooxidase | <enzyme> Rhodoquinone accepts electrons from ubiquinone during chromatophore photooxidase activity Registry number: EC 1.6.99.- Synonym: rhodoquinone photooxidase (26 Jun 1999) |
| photopathy | Synonym: photonosus. Origin: photo-+ G. Pathos, suffering (05 Mar 2000) |
| photopeak | The characteristic energies of photons emitted by a radionuclide, used to set scanning parameters. (05 Mar 2000) |
| photoperceptive | Capable of both receiving and perceiving light. (05 Mar 2000) |
| photoperiod | <ecology> Recurring cycle of light and dark periods. The natural photoperiod is approximately 24 hours, and the ratio of light to dark hours slowly changes over the course of a year. In controlled experiments, the photoperiod is usually (but not necessarily) retained at 24 hours, and the light:dark ratio is typically constant. (09 Oct 1997) |
| photoperiodism | <biology> Events triggered by duration of illumination or pattern of light/dark cycles: often the wavelength of the illuminating light is important as for example in control of circadian rhythm in plants. See: phytochromes. (18 Nov 1997) |
| photopheresis | A process in which peripheral blood is exposed in an extracorporeal flow system to photoactivated 8-methoxypsoralen (methoxsalen) and ultraviolet light - a procedure known as puva therapy. Photopheresis is at present a standard therapy for advanced cutaneous T-cell lymphoma; it shows promise in the treatment of autoimmune diseases. (12 Dec 1998) |
| photophobia | <psychology, symptom> An abnormal visual intolerance of light. Origin: Gr. Phobos = fear (16 Mar 1998) |
| photophobic | Relating to or suffering from photophobia. (05 Mar 2000) |
| photophone | <physics> An apparatus for the production of sound by the action of rays of light. Origin: Photo- + Gr. Sound. Source: Websters Dictionary (01 Mar 1998) |
| photophore | 1. A lamp with reflector used in laryngoscopy and in the examination of other internal parts of the body. 2. In bacteriology, the organ producing intracellular bioluminescence in certain organisms. Origin: photo-+ G. Phoros, bearing (05 Mar 2000) |
| photophoresis | See: extracorporeal photophoresis. Extracorporeal photophoresis, destruction of cells separated from blood in an extracorporeal flow system by ultraviolet activation of chemotherapeutic agents such as psoralens. (05 Mar 2000) |
| photophosphorylation | <plant biology> The synthesis of ATP that takes place during photosynthesis. In noncyclic photophosphorylation the photolysis of water produces electrons that generate a proton motive force which is used to produce ATP, the electrons finally being used to reduce NADP to NADPH. When the cellular ratio of reduced to nonreduced NADP is high, cyclic photophosphorylation occurs and the electrons pass down an electron transport system and generate additional ATP, but no NADPH. (31 Dec 1997) |
| photic sneezing |
Photic sneeze reflex (also whimsically called ACHOO, a backronym for Autosomal dominant Compelling Helio-Ophthalmic Outburst) is a medical condition by which people exposed to bright light involuntarily sneeze. It has been suggested that the photic sneeze reflex occurs only after someone has been adapted to the dark for at least five minutes, although this is not certain, and is not uniform amongst people with the photic sneeze reflex. ...
출처: en.wikipedia.org/wiki/Photic_sneezing
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| photoluminescence |
Fluorescence is a luminescence, i.e. optical phenomenon in cold bodies, in which a molecule absorbs a high-energy photon, and re-emits it as a lower-energy (longer-wavelength) photon. The energy difference between the absorbed and emitted photons ends up as molecular vibrations (heat). Usually the absorbed photon is in the ultraviolet, and the emitted light (luminescence) is in the visible range, but this depends on the absorbance curve and Stokes shift of the particular fluorophore. ...
출처: en.wikipedia.org/wiki/Photoluminescence
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| photometry |
Photometry is a technique of astronomy concerned with measuring the flux, or intensity of an astronomical object's electromagnetic radiation. Usually, photometry refers to measurement over large wavelength bands of radiation; but, when not only the amount of radiation but its spectral distribution are measured the term spectrophotometry is used. ...
출처: en.wikipedia.org/wiki/Photometry_(astronomy)
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| photon |
Photon was a live action series based on the infrared tag game popular in the 1980s. The series took place on Earth and in space on various worlds and involved a young human teen named Christopher Jarvis who is a champion player of Photon. He receives a mysterious message one day while playing and is transported to the ship of Mother One, the leader of the Federation of Light a galactic amalgam of beings dedicated to playing Photon and the power of good over evil. ...
출처: en.wikipedia.org/wiki/Photon_(TV_series)
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| photoautotroph |
Phototrophs or photoautotrophs are photosynthetic algae, fungi, bacteria and cyanobacteria which build up carbon dioxide and water into organic cell materials using energy from sunlight. One product of this process is starch, which is a storage or reserve form of carbon, which can be used when light conditions are too poor to satisfy the immediate needs of the organism. ...
출처: en.wikipedia.org/wiki/Photoautotroph
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